Thomas Hansmann, SMS group GmbH , Germany

Abstract:
Steel is the backbone of the future low-carbon society. As the demand for steel is set to increase for several reasons such as steel intensity of renewable energy infrastructure and further developments of emerging markets, steel is also unique in its ability to be almost infinitely recyclable. In addition, steel can plot credible technological pathways for significant reductions in greenhouse gas emissions. However, the decarbonization of the iron and steel industry faces very different regional challenges. Among the others, clear incentives lead to decisive action in Europe, with pathways mainly based on direct reduction followed by various types of electric (s)melting. The transition towards green steel though is not limited to the European steel industry but has become a global priority. In different regions of the world we are facing various initiatives to convert existing steel plants into low carbon steel production, our experience reaches from greenfield fully hydrogen based steel production up to innovative solutions for existing integrated facilities. As a global player, the SMS group faces indeed the challenge of serving these diverse conditions. Thanks to 150 years of experience we have developed a deep understanding of all the technologies and processes. Continuously searching for innovative products and methods we have made our mission to create a carbon neutral metal industry.

Bernd Wemhöner, thyssenkrupp Steel Europe AG, Germany

Abstract:
The presentation describes the structure of the process control system of the Schwelgern coking plant, starting with the initial planning, the implementation and the continuous further development during ongoing operation. The complete system, starting from the field level, which is exclusively connected to the control systems via bus systems, to the extensive visualisation of the complex processes and the database system for long-term data storage, will be explained.

Anna-Katharina Hofecker, thyssenkrupp Steel Europe AG, Germany

Abstract:
The identification of weaknesses and the analyse of production losses is crucial to ensure the stable output and the proper production planning of a coke plant. This is, compared to other steel production plants, faced by two main challenges that make the analysis complex: It never completely stops production and the redundancies of all important production components multiply information input. Coke plant Schwelgern started to implement a Digital Failure Reporting and Analyzing System to address this complexity.

Fabian Rupp, Danieli Corus B.V, Germany

Co-Author:
Miguel Furlaneto, Danieli Corus B.V

Abstract:
Whereas originally, coke plant lifetime would be determined by its technical integrity and in more recent decades by its environmental compliance, steel producers who are developing their decarbonization strategies currently face the necessity to have both these aspects match the projected termination of coke consumption at their site. Coke plant technology has been developed to such a level of maturity that lifetime extension at minimum emissions to the environment is feasible under any scenario. However, with the potentially limited lifetime requirement dictated by the selected decarbonization scenario, applying modern technology may easily stretch the plant’s lifetime beyond requirement while requiring excess capex allocation. A coke plant comprises a large multitude of refractory constructions as well as mechanical equipment, all of which are connected to the plant’s lifetime capability, process performance and environmental performance. Based on comprehensive knowledge of coke plant technology as well as decades of experience in the design, construction and maintenance of coke plants, Giprokoks and Danieli Corus have developed condition assessment and lifetime extension strategies that allow for extending a plant’s lifetime to match plant lifecycle requirements while minimizing direct cost and production loss. These strategies may include minor or major repairs of and modifications to refractories as well as repairs of and modernization of mechanical equipment such as doors, valves, hoods and mains/ducting. In any scenario, a program for minimizing emissions to the environment and to comply with regulations will be advised.

Murat Yaman, Ereğli Iron and Steel Works, Co., Turkey

Co-Author:
Bülent Öztürk, Ereğli Demir ve Çelik Fabrikaları
Viorel Patriche, Fosbel GmbH
Tuna Keskinel, Ereğli Demir Çelik Fabrikaları
Christophe Leborgne, Fosbel GmbH

Abstract:
Oven walls in coke batteries that are in production for a long time can be damaged due to various reasons. To ensure production continuity, it is important to select a low-cost, short-time requiring, and effective method. Gunning, ceramic welding, and hot repair methods are the methods that can be selected in the repair process. Methods such as ceramic welding and gunning can be selected as a solution to light damages, but the repair of deepest damages reaching to middle section of the oven can be done by the hot repair method. Between battery wall repair methods, the most effective solution is the process of removing the bricks and knitting from it which is called hot repair. In this article, the methods that can be selected in the repair process of the oven refractory structure in batteries that have been manufactured for more than fifty years have been reviewed. It has been described that the repair of light and severe damages occurring to these batteries is possible in a short time with the recently developed material (Fused Silica Gunning Material). With this material, the life of the ovens was extended to 6 months by casting (gunning) to the depths of four and six combustion chambers in heavily damaged ovens requiring hot repair, which is deepest repair in the world. In these ovens production is continued thanks to this application. The existing refractory structure of ERDEMIR coke batteries, which continued to be in production since 1964 and which is one of the oldest batteries in the world, and the formation process of the structural damages have been demonstrated.

Katja Windt, SMS group, Germany

Abstract:
Today, remote operation of entire plant complexes is no longer a vision. Fundamental technological developments from the field of digitization and automation, such as, 5G or hybrid process modelling or self-learning capabilities, make it possible to fundamentally re-design the operation of highly complex, industrial plants. They offer the possibility to bundle highly qualified experts in centralized control centers. For manufacturers operating at multiple locations, this can bring major benefits. In addition to business benefits such as increased productivity and product quality, centralized training centers can improve the quality of employee education, while the physical distance between the plant and centralized training or control centers increases employee safety. The use of advanced predictive technologies in the fields of plant maintenance, energy, emissions and product quality also makes it possible to further increase production sustainability by increasing plant availability, lowering overall energy consumption, reducing emissions and improving product quality. To get there it means to change the way production plants are operated and operator teams work. First, it needs transparency. Data and insights into the current planned operation, equipment and process condition and production plans are a crucial prerequisite. All information must be gathered, suitably stored and presented in centralized control rooms in which one control pulpit operates several production steps centrally. Additional AR/VR tools support both operators and on-site crews in the way they interact and communicate. Ultimately, it needs operator teams with a diverse skill set. Data science like AI, metallurgical process knowhow and operator experience need to come together in order to understand the gathered data, derive matching actions and execute those successfully.

Jan Eisbacher-Lubensky, Montanuniversität Leoben , Austria

Co-Author:
Christina Brus, voestalpine Stahl Donawitz GmbH
Stefan Wegscheider, voestalpine Stahl Donawitz GmbH
Christian Weiß, Montanuniversität Leoben

Abstract:
In the sintering of iron ores, the chemical composition and the physical properties of coke breeze has a significant effect on the sinter process and the sinter quality. This paper is focused on the influence of coke breeze from different deposits and coking plants respectively, on the sinter process in particular on the off gas composition and the sinter quality. Laboratory-scale sinter feed mixtures with various sorts of coke breeze are produced, whereby the particle size distribution of the investigated coke breeze is constant as well as the coke breeze content with respect to the fixed carbon content. The small scale sinter experiments are performed in cylindrical packings of sinter mix. During the sintering the emissions of CO, CO2, NOx and SO2 in the off gas are monitored, as well as specific sintering parameters e.g. the sinter yield and strength. The results of the off-gas analysis are compared with the chemical elemental analysis of the coke breeze. The investigations demonstrate that a high carbon content of the coke breeze leads to a higher pressure loss across the sinter bed, thus to a shorter sintering time and correspondingly to higher productivity. Changes in the nitrogen concentration in the coke breeze cause significant NOx variations in the off gas. As expected, the total sulfur in the off gas cannot be entirely attributed to the coke breeze. The findings obtained on a laboratory scale enable a coke breeze characterization close to an industrial sinter belt, demonstrating the expected process parameters.

Johan Martinsson, Swerim AB, Sweden

Co-Author:
Niklas Kojola, Hybrit Development AB
Oscar Hessling, Swerim AB

Abstract:
In view of transforming the heavily fossil-dependent iron and steel production into a fossil-free hydrogen-based production, the iron ore pellet could be modified to better suit the fossil-free iron and steel production, including the whole value chain. Considering the higher production cost associated with green hydrogen, the pellet could be optimized to save both material and energy costs during the melting and refining processes of the hydrogen direct reduced iron (H-DRI). At the same time, the modified pellet must keep sufficient mechanical properties as well as reduction properties. A preliminary study is therefore conducted, where the effect of varying CaO/SiO2-ratio was studied with regards to mechanical properties of the pellet, the reduction rate, as well as the dephosphorization ability (wt% P in iron) of the resulting autogenous slag. For this purpose, pellets with three different CaO/SiO2-ratios were studied, ranging from 0.8-1.4. In addition, two iron ore discs were made to broaden the CaO/SiO2-ratio range from 0.2 to 2.4 for the dephosphorization study. The three pellets were supplied by LKAB. Cold compression tests were made to determine the mechanical property. A high temperature resistance furnace was then employed to both follow the reduction of the iron ore using 100% hydrogen, and for melting the H-DRI to study the dephosphorization. While the reduction rate and mechanical properties did not vary significantly within the studied CaO/SiO2-ratio range, it was found that small differences in basicity in the autogenous slag could affect the dephosphorization significantly. The present work therefore finds it highly possible to optimize an iron ore pellet to save material and energy costs during the melting and phosphorus refining.

Maycon Athayde, Minerai de fer Quebec, Canada

Co-Author:
François Lavoie, Champion Iron
Josiane Caron, Quebec Iron Ore

Abstract:
Cold bonding pellet can turn into and important process in the ironmaking industry, eliminating carbon intensive process. However, this route presents high-temperature metallurgical challenges due the behavior in the blast furnace process. The ability of the material to maintain its strength and structure and resist degradation is crucial for producing high-quality h-CBP. In the last years, Champion Iron, a high-grade iron ore concentrate producer in Quebec, Canada have been developing a solution to supply to the ironmaking industry. Previous technologies focused on either organic or inorganic binder systems. A hybrid inorganic-organic binder was formulated, to overcome the weaknesses of the other. Unlike cementitious binders, no thermal conversion is occurring around 750°C, leaving much more leeway to maintain cohesion up to the cohesive zone. Organic portion of the binder provides bonding with both the iron oxides and the inorganic binder, to give the required physical properties. Additionally, the organic content aids the manufacturing process and aids stability, when in the unhardened phase. The 10 m drop test results of 86.9% -6.3 mm and 2.0 % -0.5 mm are slightly below the range of seaborne trade pellets values of 92.4 %-6.3mm and 1.5 %-0.5mm. The reducibility of 0.67 %O2/min is higher traded acid pellets value for BF (0.4-0.6 %O2/min). In this work a modified BRASS test is presented to better characterise the behavior of the h-CBP’s in the non-isothermal blast furnaces. Also, the test was interrupted in different zone to evaluate the progression of the reaction. The results presented also satisfactory reduction rate at the end of thermal reserve zone, and lower fine generation as compared with traded pellet. Champion Iron has been successfully designing a new concept that supports decarbonized hot metal production from a blast furnace with a stable contribution to the ferrous burden, like a traditional product.

Tobias Stefan, Métal 7 inc., Canada

Co-Author:
Steve Beaudin, Métal 7 inc.
Alexandre Goncalves Andrade, Métal 7 inc.

Abstract:
The iron and steel industry is one of the largest industrial emitters of Greenhouse-gas emissions. Most companies are currently undertaking unprecedented steps to transform their production from the traditional blast furnace route to DRI-EAF based steelmaking using hydrogen. At the same time, the required raw material qualities become more and more scarce. Consequently, the key input material for iron making will gradually shift to pellets. In anticipation of a growing demand, more pellet plants are expected to be built in the coming years We would like to discuss the possibilities to decarbonize this important part of the value chain and the possibilities to impact the downstream reduction processes. Up to 20% on energy savings in the pelletizing plants are possible by the correct combination of equipments and technolgoies. In addition, fired pellet quality can be positively influenced by green pellets quality, shape, homogeneous size distribution and reducibility. All those parameters can help save significant amounts of reductant and heating energy in the downstream processes leading to a multiplication of direct CO2 savings.

Faisal Qayyum, Technische Universität Bergakademie Freiberg, Germany

Co-Author:
Ulrich Prahl, Technische Universität Bergakademie Freiberg
Seigfried Schmauder, University of Stuttgart
Sergey Guk, Technische Universität Bergakademie Freiberg
Ali Cheloee Darabi, University of Stuttgart

Abstract:
This study aims to investigate the effect of chromium and molybdenum on the formation of pearlitic microstructure in 1% carbon steels. To obtain experimental data, 12mm wires of one benchmark (Fe-1C) and two trial alloys (Fe-1C-1.5Cr and Fe-1C 1.5Mo) are manufactured in-house by casting and hot caliber rolling. These wires are homogenized at a temperature of 1200°C for a holding time of 12 hours. MatCalc and JMatPro software are used to identify the time-temperature and transformation curves for each alloying system. The effects of transformation times and holding temperatures on the pearlite morphology in each alloying system are systematically analyzed and compared by examining the resulting microstructures under an electron microscope. The microstructural features such as lamella length, lamella thickness and inter-lamella spacing for each case are quantitatively analyzed by post-processing the image data using FiJi-ImageJ and Python scripts. The probability and cumulative distribution plots of the microstructural features allow for the comparison and selection of optimal process routes for obtaining similar pearlitic microstructures across all alloying systems. Furthermore, a phase field simulation is performed to find an optimized heat treatment. The accuracy of the phase field models is validated through experiments. The heat treatment routine for pearlite formation in all three steels is simulated using the MICRESS software and the resulting microstructures are compared with the experimental results. To reduce computational cost, the heat treatment simulations are started from the fully austenitic microstructure and the morphology for this condition is calculated using MatCalc software. The pearlite formation heat treatment is simulated and the thermodynamic parameters are extracted using MatCalc software and literature. With the validated models, microstructures under different heat-treatment processes can be predicted and an optimized heat-treatment condition for all three materials can be obtained.

Niklas Fehlemann, RWTH Aachen University, Germany

Co-Author:
David Lenz, RWTH Aachen University
Yannik Sparrer, RWTH Aachen University
Markus Könemann, RWTH Aachen University
Sebastian Münstermann, RWTH Aachen University

Abstract:
High-strength structural steels (from 960 MPa upwards) are becoming increasingly important in modern steel construction applications. These steel grades are particularly suitable for reducing sheet thicknesses of components and thus enabling more sustainable construction. The low-temperature properties are also of great importance, and a profound understanding is necessary in order to exclude the risk for catastrophic failure due to cleavage fracture in the component design. In this study, the low-temperature properties of a structural steel of type S960 were investigated. For this purpose, specimens of different stress states (including shear, plane strain and notched round bar) were quasi-static tested in a bath of liquid nitrogen at -196°C. The resulting properties were analyzed in terms of ductility and strength and compared with the same properties at room temperature. For this purpose, a failure locus based on stress triaxiality and lode angle parameter and equivalent plastic strain was fitted to the data. In addition, the critical cleavage fracture stress of the material is identified. The probabilistic nature of the low-temperature properties was captured using a cumulative Weibull distribution so that a locus for different failure probabilities can be determined. The results show a pronounced dependence on the stress state, which is more pronounced at cryogenic temperatures than at room temperature. In the last step, a comparison was made with a high strength a pipeline steel. Comparable tendencies were found at room temperature, but a clearly different behavior at low temperatures. This shows that the stress state dependence of the low-temperature failure properties is clearly material-dependent and large deviations can occur for different steel classes. These results can be used to calibrate damage mechanics simulation models, which can significantly accelerate efficient design of steel components for various applications.

Silke Klitschke, Fraunhofer Institute for Mechanics of Materials , Germany

Co-Author:
Andreas Trondl, Fraunhofer Institute for Mechanics of Materials
Florence Andrieux, Fraunhofer Institute for Mechanics of Materials
Dennis Revin, Fraunhofer Institute for Mechanics of Materials

Abstract:
AHSS are widely used in crashrelevant components of automotive structures. Because of their low ductility an accurate failure prediction is mandatory for this class of materials. Hence, in the past different complex failure models have been developed. The calibration of those failure models is usually based on experiments with defined stress states, partly at different strain rates. Though, there is still a lack of suitable experiments for the validation of those calibrated failure models from quasi-static up to crash relevant strain rates cover-ing different complex loading situations. These validation experiments should be suitable for a wide range of test speeds, lead to nearly plane stress states from compression/shear to multiaxial tension and should show characteristic damage. In this contribution experimental validation concepts were developed and applied to a DP1000 steel sheet and a ZStE 340 steel sheet. These validation experiments are appropriate for quasi-static and highspeed testing. The key of these validation tests is to develop specimens with different potential critical areas. De-pending on the failure behavior of the material, failure occurs in the shear or in the nearly plane strain re-gion. Especially the safety-critical negative strain rate effect concerning the shear failure strain of advanced high strength steel sheets can be validated by the proposed new material dependent shear-tensile validation test. The specimen geometries are designed depending on the ductility of the material and the manufactur-ing is performed without any joining procedure. Local failure initiation on the surface of the specimens is observed by highspeed video recording and verified by FE-simulations. With these experimental concepts the validation procedure of failure models can be performed cost-efficient and reliable over a wide range of stress states and strain rates. This leads to an improvement in failure prediction and utilization of the light-weight construction potential of AHSS sheets in automotive applications.

Vahid Javaheri, University of Oulu, Finland

Co-Author:
Jukka Kömi, University of Oulu
Saeed Sadeghpour, University of Oulu
Sakari Pallaspuro, University of Oulu

Abstract:
Abstract: Isothermal bainitic transformation below the Martensite start temperature (MS) has been reported in previous works [1,2]. The current study investigates the effect of bainite formation below the MS temperature where the athermal martensite formation is interrupted, on the final tensile properties. The studied material is a 0.4 (wt.%) carbon, low-alloy steel subjected to different thermal cycles in order to produce different fractions of martensite and bainite. Gleeble 3800 thermo-mechanical simulator machine was employed to perform all the cycles as well as to provide the dilatometric data. In the experiments, each sample was heated to the temperature of 850 °C at a rate of 50 °C/s and was held for the 30s. Then, the samples were quenched to a temperature between MS and MF followed by a subsequent isothermal holding in the MS–MF temperature window. A field emission scanning electron microscopy equipped with an electron back-scatter detector was used for microstructural characterization. The results showed that low-temperature bainite formation below the MS significantly improved the ductility of the samples although the strength decreased slightly. References: [1] S. Samanta, P. Biswas, S. Giri, S.B. Singh, S. Kundu, Formation of bainite below the M temperature: Kinetics and crystallography, Acta Mater. 105 (2016) 390–403. https://doi.org/10.1016/j.actamat.2015.12.027. [2] S.M.C. van Bohemen, M.J. Santofimia, J. Sietsma, Experimental evidence for bainite formation below Ms in Fe–0.66C, Scr. Mater. 58 (2008) 488–491. https://doi.org/10.1016/j.scriptamat.2007.10.045.

Renata Latypova, University of Oulu, Finland

Co-Author:
Jukka Komi, University of Oulu
Vahid Javaheri, University of Oulu

Abstract:
Abstract: This study investigates the effect of rapid tempering and cementite morphology on hydrogen permeation and diffusion in a medium carbon steel. Three materials were tested: (1) direct-quenched, (2) direct-quenched and rapid tempered at 420°C, and (3) direct-quenched and rapid tempered at 720°C. The results showed that rapid tempering at 420°C and 720°C led to a significant decrease in the dislocation density of studied materials compared to the direct-quenched sample. In addition, higher tempering temperature resulted in a higher fraction of cementite precipitation as well as a change in the cementite morphology from the continuous stick-like structure to a more fragmented, discontinued, and globular type. Electrochemically hydrogen permeation tests revealed that direct-quenched samples could reach the saturation level much faster than the other two tempered samples and also had the lowest diffusion coefficient. It means less trapping site to be occupied but stronger to hinder the hydrogen mobility. Direct-quenched and rapid tempered at 720 °C needed a relatively longer time to reach the saturation level but on the other hand, it showed the highest diffusion rate among all samples. Overall, this research highlights the morphology of cementite and dislocation density of the studied samples in the hydrogen permeation and diffusion properties which is very important when developing of hydrogen-resistant steels.

Vasile Danut Cojocaru, University Politehnica of Bucharest, Romania

Co-Author:
Elisabeta Mirela Cojocaru, University Politehnica of Bucharest
Nicoleta Zarnescu-Ivan, University Politehnica of Bucharest
Nicolae Serban, University Politehnica of Bucharest
Mariana Lucia Angelescu, University Politehnica of Bucharest

Abstract:
The influence of solution treatment duration on the microstructure and mechanical properties of a hot-rolled UNS S32750 / F53 / 1.4410 Super Duplex Stainless Steel (SDSS) alloy was investigated in this study. The UNS S32750 / F53 / 1.4410 SDSS alloy was thermomechanical (TM) processed by hot-rolling deformation at a temperature of 1100°C with a total deformation degree (total applied thickness reduction) of 70%, followed by a solution treatment. The solution treatment was performed at temperatures between 1080°C to 1180°C, in 20°C increments, with a fix treatment duration of 20min. The microstructure evolution during TM processing was investigated by XRD and SEM-EBSD techniques, while the mechanical properties by tensile and impact testing techniques. The following microstructural characteristics were analysed: constituent phases, weight fraction, grain-size and phase morphology. The mechanical behaviour was assessed through the following properties: absorbed energy, ultimate tensile strength, yield strength and, elongation to fracture. The performed solution treatments induced significant changes in relation to alloy's microstructure and showed a direct influence on the exhibited mechanical behaviour.

Dennis Fischer, D.A.R. Metall AG, Germany

Co-Author:
Felix Kaiser, RWTH Aachen University
Tim Reichel, RWTH Aachen University
Vladimir Vakulchuk , D.A.R. Metall AG
Pioh Cho, Genco Co. Ltd.
Herbert Pfeifer, RWTH Aachen University

Abstract:
The steel industry produces with approx. 1,7 t Greenhouse Gas (GHG) emissions per 1 t crude steel around 10 % of all GHG-emissions worldwide. Thus, a transformation towards green steel production by replacing fossil- or carbon-based energy supply as well as feedstock by alternative resources, like renewable energy and hydrogen gas, is inevitable. However, this transformation is facing challenges since it requires significant technological changes and developments, which need expensive investments and will take around 10 to 15 years until they are completely implemented. To reduce the GHG-emissions already during this transition phase it is essential to modify individual processing steps and materials. Modifications in these process sections can be realised in short time and require low investments but can have a high impact on the reduction of GHG-emissions. Moreover, when the perspective of producing GHG-emissions is expanded beyond the borders of a local production facility onto the supply chain of input materials for steel production processes, there is an additional high potential reducing GHG-emissions. For instance, the replacement of natural resources by alternative input material with a low carbon footprint (CFP), like recycled or secondary raw material, will support lowering the GHG-emissions as well as conservation of resources. This contribution presents three possibilities to lower the GHG-emissions: The substitution of fossil coal by recycled plastic waste with a low CFP, utilization of recycled aluminium granules with a low CFP in combination with an efficient deoxidation injection method as well as innovative refractory materials, which does not contain carbon nor cement and show a higher durability in comparison to usual material. Based on various use cases within steel production considering blast furnace and electric arc furnace routes, the emission savings of the different solutions are presented.

Robert Claußnitzer, AKW Apparate + Verfahren GmbH, Germany

Abstract:
Almost all the iron and steel manufactured in the world is made from pig iron produced by the blast furnace process (BF). However, the dust and especially the sludge generated during the process, do constitute a great challenge for the improvement of the overall sustainability of this highly material and energy intensive industry. During the production of pig iron in blast furnace, a Zn- and Pb-containing sludge is generated in the exhaust air cleaning system. More than 50 % of the mass input becomes outputs in form of off-gas and solid wastes/by-products. This toxic waste can be landfilled after dewatering and pretreatment, which is very costly. The sludge particles contain large amounts of Fe and C that could be recycled in the furnace. However, the Zn content of the sludge is high, and the Zn input to the blast furnace must be limited. There are no standard processing concepts for a BF-sludge treatment plant. The process design and plant arrangement will primarily depend on the nature of the feed sludge and therefore will be based on analysis and pilot test work that is being performed in AKW Equipment + Process Design technical laboratory. On basis of the test results, the suitable and customized process solution will be developed, discussed and later on engineered and executed by AKW Equipment + Process Design. This unique process concept is presented in the following paper: multi-stages hydrocycloning, combined with thickening and filter pressing. Key Words Blast Furnace Sludge, Zn-reduction, Hydrocyclones, Thickeners, Filter Press,

YongWoo Kim, Chosun University, Korea, Republic of

Co-Author:
Sun–Joong Kim, Chosun University

Abstract:
The consumption amount of plastic has increased over the past. Generally, the waste plastics are landfilled or incinerated, which caused environmental problems. Waste polymers, whose main components are carbon and hydrogen, partially replace coke as a carbon source in the EAF process and have the potential for savings of electricity and carbon resources. It is necessary to effectively utilize the waste polymer as a reducing agent by comparing the various properties of waste polymer with those of pure plastics (PE, PP, and PS). In this study, the effect of waste polymers addition on the reduction behaviors of iron-containing by-products was conducted. In addition, the metallurgical properties of the pure polymers and waste polymer were investigated by FT-IR, DSC, and pyrolysis analysis for by-product gas during the reduction reaction.

Manuel Mosconi, Tenaris S.A., Italy

Co-Author:
Cesare Giavani, Tenova S.p.A.
Fabio Melloni, Tenova S.p.A.
Enrico Malfa, Tenova S.p.A.
Marta Guzzon, Tenova S.p.A.
Filippo Cirilli, Rina Consulting – Centro Sviluppo Materiali S.p.A
Loredana Di Sante, Rina Consulting – Centro Sviluppo Materiali S.p.A
Fabio Praolini, Tenaris S.A.

Abstract:
Plasma Reactor to Recover Valuable Metal and Mineral Fraction from Steelmaking Residues Marta Guzzon, Enrico Malfa, Fabio Melloni, Cesare Giavani, Tenova S.p.A. Fabio Praolini, Manuel Mosconi, Tenaris Dalmine Loredana Di Sante, Filippo Cirilli, RINA CSM The EU production of steel in 2021 was more than 150 million tons: 56% from BF/BOF route and 44% from EAF route. This process produced several million tons of residues containing iron oxide, zinc oxide and other valuable metals. Tenova, according to the mission to develop sustainable solutions for the steelmaking, designed a stand-alone process, that can be operated in EU steel shop, to recover the valuable elements present in the steel making residues contributing to a reduced demand of primary resources in a circular economy approach. In the frame of Horizon EU – REMFRA project, Tenova together with Tenaris Dalmine and RINA- CSM will test at the industrial scale a Plasma Reactor for the recovery of iron oxides from different residues, implementing the use of secondary carbon carrier materials. The Tenova Plasma Reactor is based on plasma technology (electrical arc generated by graphite electrodes) working in reducing atmosphere. This pyrometallurgical process has been selected since it can: • treat a large variety of waste streams: by-products coming from the steel industry (slag, scale, dust, sludge), incinerator ashes, catalyst for vanadium (V, Ni, Mo, Co), Mn-sludge, Ni-dust, Al dross and red mud. • use as reducing agent residuals containing C (i.e. biomass, waste polymers, petro-chemical residues) • accept residual containing Si (ceramic, refractory and glass). In the paper, the status of activities and development of Plasma reactor in the frame of the REMFRA project will be presented.

Winfried Ruhkamp, Loesche GmbH, Germany

Co-Author:
Holger Wulfert, Loesche GmbH
Andreas Jungmann, Cala Aufbereitungstechnik GmbH & Co. KG

Abstract:
The development of recycling processes for the use of material resources from industrial waste products or by-products is becoming more and more important. To this end, comminution processes play a key role in processing the material in such a way that recyclable materials become exposed for subsequent separation processes. It was therefore only a matter of time before LOESCHE GmbH, with its decades of experience in fine comminution processes, became the centre of attention for prospective customers who would like to develop and optimize recycling processes. Worldwide three digit mio. tons of steel slags are being produced yearly. The paper/presentation focuses on the development of a dry grinding process for the metal recovery from stainless steel slags. The first production plant worldwide for the dry processing of stainless steel slags with a vertical roller mill was commissioned in Charleroi/Belgium in 2012. The throughput of the plant is ~ 20 t/h. The ground slag has a fineness of approx. 3500 Blaine. The metal recovery is bigger than 90%, the metal content of the concentrate is between 85 to 95% (recoverable metal bigger than 63µm). In addition, the presentation will highlight further possibilities for slag processing and provide an outlook on future technologies that close the steel production loop and increase sustainability.

Joerg Bollmann, John Cockerill, Germany

Abstract:
Authors: Jörg Bollmann, John Cockerill UVK GmbH, Sergej Faber, John Cockerill UVK GmbH  Eco-friendly Acid Regeneration to help decarbonize the steel industry Acid regeneration systems are to reduce pickling process plants’ fresh acid demands and waste streams in general. With both, environmental protection and operating expenditure having substantially expanded in their importance, total acid regeneration plants based on the fluidized bed (FB) technology became today’s state of the art technology for premium steel suppliers increasingly committed to reducing their environmental footprint. In response to this trend, John Cockerill’s latest FB acid regeneration plants (ARP) come with an innovative and environmentally friendly concept, particularly in terms of emissions and waste energy recovery, along with smart and Industry 4.0 technologies. In combination with a perfectly matched tank farm guaranteeing the efficient management of all consumables, today’s highly automated ARPs allow the effective recycling of close to 100% of the spent acid generated in the steel manufacturing process, all while providing the highest possible process security, throughput, and plant availability. What is more, it is considerably reducing the steel complex’s annual dust and mist emissions and lowering or even eliminating other waste streams.  An eloquent testimony of the of the above, is the world’s largest ARP recently supplied to Chinese steel giant Baowu. It allows Baowu to achieve emissions that are only 1/3 of the very latest stringent Chinese standards. Namely the reduction of its steel plant’s dust emissions by 25 tons and its carbon footprint by a significant 4,800 tons per year. Simplified processes, such as quick-change spray/burner nozzles, our maintenance free venturi, our smart plant control system, or our Air Preheating System reducing fuel consumption and the CO2 footprint by a minimum of 10%, are only some of the many sustainable features that will be presented.

Elina Fernö, Swerim AB, Sweden

Co-Author:
Elina Fernö, Swerim AB
Xianfeng Hu, Swerim AB

Abstract:
The ironmaking process utilising the blast furnaces releases a significant amount of CO2 into the atmosphere due to using coke/coal as reductants and fuels. Innovative technologies are needed to meet the Paris agreement and reduce CO2 emissions in the ironmaking process. Electrolysis, which employs electrons generated from electricity as the reductants, is one of these alternative technologies. When electricity produced from renewable sources is applied, and an inert anode is employed in the electrolysis process, the process will be completely green, yielding iron as a product and oxygen as a byproduct; meanwhile, no CO2 is released. In this study, we investigated the electrolytic reduction behaviors of pure chemicals (or synthetic chemicals) of wustite, hematite, and magnetite, as well as magnetite-type iron ore in the molten NaOH salt (kept at 500 °C). There was at Swerim (Luleå, Sweden) established a pilot-scale electrolysis reactor, in which the materials of interest up to 60 grams were tested at the cathode, and a graphite electrode was applied as the anode. A series of electrolysis reduction trials were conducted at a constant cell voltage of 1.7V to understand how iron oxides with different valence statuses are reduced and how the gangue materials in the iron ore can affect the electrolytic reduction process. The results show that iron oxides/ore can be reduced into metallic iron electrolytically in molten NaOH salt. There is a stepwise reduction of iron oxides from a high valence to a low one. The knowledge obtained in this study provides a better understanding of the electrolytic reduction behaviors of iron oxides/ore, thus assisting in developing a CO2-free molten salt electrolysis process for ironmaking when an inert anode is applied. Also, this study provides knowledge for the electrolytic reduction of other transition metal oxides in molten salt.

Ryota Higashi, Tohoku University, Japan

Co-Author:
Daisuke Maruoka, Tohoku University
Taichi Murakami, Tohoku University
Eiki Kasai, Tohoku University
Yuji Iwami, JFE Steel Corporation

Abstract:
The iron making industry consumes a large amount of fossil fuel derived carbon as heat source, reducing agent of iron ores and carburizing agent of reduced iron. Carbon is an essential element for an efficient ironmaking, although hydrogen is expected to be the substitution. The carbon recycling ironmaking process by circulating CO gas has been already proposed to achieve carbon neutrality. However, the production of hot metal is not considered in this process because CO gas is not utilized as a carburizing agent. In order to apply the carbon recycling ironmaking process to the production of the hot metal, new ironmaking process of carbon solidification using porous iron whisker and production of hot metal using recovered carbon-iron ore composite is proposed in this study. The lumps of iron whisker with high porosity, approximately 95% were obtained by heating the mixture of fine hematite reagent and biomass char at 950℃ for 75 min. The lumps were utilized as the catalyst of the carbon solidification reaction under the gas flow of CO at 600℃. The recovered solid carbon samples with different cementite/free carbon ratio were obtained by changing the reaction time. The composite made of the obtained carbon powder and hematite reagent was heated in order to proceed the reduction of the iron oxide and carburization of reduced iron. The molar ratio of carbon to oxygen in the composite was set as from 0.8 to 1.0. The composite started to be reduced at 700℃ and then reduction degree increased sharply at 900℃. The molten iron nuggets were observed on the surface of the composite samples heating up to 1300℃. These results indicate that the suggested carbon recycling ironmaking process may contribute to forward not only carbon neutrality but also rapid hot metal production.

Simon Wölfelschneider, VDEh-Betriebsforschungsinstitut GmbH, Germany

Co-Author:
Thomas E. Müller, Ruhr-Universität-Bochum
Dennis Panke, Ruhr-Universität-Bochum
Michael Hensmann, VDEh-Betriebsforschungsinstitut GmbH

Abstract:
This work presents the melt-recrystallisation process as a possible solution for the sustainable use of carbon-containing materials, that would otherwise be burned or landfilled. Of interest are for example residuals or carbonaceous co-products from pyrolysis processes. Although these materials consist almost exclusively of carbon, they are lacking major fields of application. The melt-recrystallisation process provides a pathway towards these applications, as the low-grade carbon products can be upcycled to a graphitic carbon nano material, generally referred to as graphene nano platelets (GNP). GNP are sheets of hexagonally arranged and covalently bonded carbon atoms in µm-scale, forming stacks of about ten atomic layers. There is a wide spectrum of applications for GNP, ranging from high end electronics to corrosion protection and industrial lubricants. However, the most promising field for large scale application are composite materials, especially as additives in polymers and cement, in which GNP can induce an improvement of the mechanical properties. The process concept is based on dissolving defined amounts of carbon residual in molten alloys containing Fe or Ni. Afterwards the carbon is precipitated under defined conditions, forming the GNP at the melt surface. The formed GNP must then be removed from the surface of the liquid melt, to avoid prolonged growth of the crystallites into larger graphite particles. Therefore, a concept for removing the GNP from the melt surface is designed and tested. Furthermore, the influence of alloy composition, annealing time, and cooling rate on the crystal structure of the produced carbon nano material are evaluated. Analysis methods include Raman microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. The results indicate that indeed various types of GNP can be produced via melt-recrystallisation. Nonetheless, the separation of the produced GNP from the melt surface provides a challenge and is also affecting the product quality.

Marco Rische, ABP Induction Systems GmbH, Germany

Co-Author:
Josef Gahleitner, Primetals Technologies Austria GmbH
Axel Walther, ABP Induction Systems GmbH
Martin Ennen, ABP Induction Systems GmbH

Abstract:
The steel industry is the second largest industrial emitter of CO2 emissions worldwide. The increasing pressure to reduce these emissions is leading to a move away from fossil fuels in the future. Alternatives are the use of green energy via the generation of DRI/HBI for pig iron production with green hydrogen. In further processing, this opens up new possibilities for alternative applications in the steel making and rolling mill processes, which offer almost CO2-free heating of the material, both in the melting process and in reheating. One of these alternative processes is induction. The energy input is achieved directly via the electromagnetic field into the material to be heated. The process is dynamic, easily controllable and, if green energy is used, almost CO2-neutral. Both in the melting process and in the area of reheating, the established processes can thus be complemented and thereby reduce the emissions of the overall process. The hybrid addition of induction heating systems not only improves the emission behavior in the overall process at manageable investment costs: Due to lower burning rates of the aggregates and an extremely good stirring effect during the melting process, the process is excellently suited for melting aggregates at the lowest possible energy consumption with good mixing of the target analysis in the melt and with higher yields as conventional processes contribute. With the dynamic behavior in the heating process due to the direct energy input into the material, the induction heating process is also a good alternative to the existing gas furnace for reheating. The induction furnace can be positioned complementarily upstream or downstream of the gas furnace. Both variants enable a reduction of the total energy consumption as well as the gas consumption and thus a directly measurable CO2 reduction in the reheating process.

Fabian Krause, SMS group, Germany

Co-Author:
Andreas Kemminger, SMS group
Hans-Jürgen Odenthal, SMS group
Johannes Wilkomm, RWTH Aachen University
Johannes Henrich Schleifenbaum, RWTH Aachen University
Christian Goßrau, RWTH Aachen University
Manfred Wirsum, RWTH Aachen University
Florence Cameron, RWTH Aachen University
Huanhuan Xu, RWTH Aachen University
Heinz Pitsch, RWTH Aachen University

Abstract:
Electric steelmaking using scrap generates 80% less greenhouse gases than the blast furnace route. The electric arc furnace (EAF) is usually equipped with natural gas (NG) burners that melt down the scrap and decarburize the melt. Many activities are underway to replace NG, at least to a large extent, with hydrogen. Hydrogen has complex combustion properties, e.g. high burning velocity, low ignition energy, low volumetric energy density, and wide flammability limits, which places high demands on the burner design. Here, additively manufactured (AM) burners open up new avenues with regard to the gas/water routing, and thus show significant advantages over conventional burners when using hydrogen. These avenues are being explored within the HyInnoBurn project. This project is part of the German Clusters4Future initiative (supported by the German Federal Ministry of Education and Research, BMBF) with partners from the entire hydrogen value chain and focuses on the development of additively manufactured burners for flexible use of NG and hydrogen. The presentation gives an overview of Computational Fluid Dynamics (CFD) simulations, manufacturing approaches and experiments at small-scale 50 kW and 450 kW burners. All burners are additively manufactured with a new and pure copper powder. High resolution combustion simulations show the fundamental flame structure, temperature and species distribution as well as the influence of increasing hydrogen amounts. While the 50 kW burner is examined with advanced laser diagnostics, the 450 kW burner is tested in an industrial sized furnace at the Gas- und Wärme-Institut (GWI) Essen. Difficulties and possible solutions for the change from NG to hydrogen are discussed.

Itsaso Auzmendi, Sarralle, Spain

Abstract:
Success stories towards CO2 neutral steelmaking via hydrogen-based technologies Sarralle has decades of experience on helping steelmaking companies in the challenge of decarbonization and sustainability. Moreover, through their division Environment & Energy, we can offer technological solutions for industrial sectors related to the Circular Economy and Energy, including the integration of green hydrogen technologies in the industry. Sarralle offers oxy-combustion and hydrogen technology applicable to EAFs, Ladle and Tundish Preheaters, Reheating Furnaces and Oxyfuel-Cutting, thus enabling savings in natural gas consumption and the total decarbonization of these equipment. Sarralle, together with one of its European customers, has implemented their oxy-combustion and hydrogen technology in a ladle pre-heater, using 100% hydrogen. The Spanish company owns also a prototype of a reheating furnace at scale, designed to operate with 100% hydrogen, both with air and oxy-combustion burners, and they are currently working on the conversion of an industrial reheating furnace in a European steelmaking plant, for the installation of their oxy-combustion and hydrogen technology in one furnace zone. The goal of this cutting-edge technology offered by Sarralle is to optimize the process efficiency as well as to reduce the emissions generated in existing installations, replacing the air used as an oxidizer with oxygen, being able to keep natural gas as a fuel, or taking a step further by using 100% green hydrogen. By using green hydrogen, all CO2 emissions are eliminated as only water vapor is generated in its combustion.

Martin Fein, Andritz AG, Austria

Co-Author:
Andreas Rechberger, Andritz AG
Vasile Jechiu, Andritz AG
Philippe Reynes, Andritz AG

Abstract:
This paper reports on a strategy of alternative heating solutions for a continuous galvanizing line in order to prevent any direct CO2 emissions, increase efficiency and production at the same time. This is possible by replacing common natural gas-fired radiant tubes with a new electrical heating system without modification of existing furnace setup, minimizing down-time and reducing the OPEX (lifetime increase and easier maintenance). The system – developed by ANDRITZ - is based on existing and reliable technologies and eliminates NOx emissions completely. In addition, to electrical heating, an advanced type of hydrogen-ready burners was developed to replace the consumption of natural gas on direct fired furnaces – combined with decreasing respective CO2 emissions – potentially using green hydrogen. The performance of the new Green Hydrogen burners has been validated with CFD simulations, confirmed by laboratory tests with full hydrogen operation. This internal development started 2 years ago has been confronted to customers, then validated during detail study in partnership with one of our long term and key clients. The study confirmed the expected results and even more, leading us to go further, building dedicated test furnaces and schedule industrial tests. The electrical test furnace is already in use to validate customer specific configurations in real operating conditions.

Andrea Turolo, SMS group, Italy

Co-Author:
Pietro Della Putta, SMS group
Umberto Zanusso, SMS group
Jimmy Fabro, SMS group

Abstract:
An important area of application for hydrogen in steel production is the field of reheating and heat treatment furnaces. On the way to more environmentally friendly steel production SMS group has developed a flameless, extra-low NOx burner: the SMS ZeroFlame HY2. This burner can work with outstanding process and environmental performances on any given mixture of hydrogen and natural gas up to 100% of H2, thus accompanying step-by-step the transition to the hydrogen economy from the present paradigm based on fossil fuels combustion. Besides the CO2 emission reduction due to the use of hydrogen as an energy carrier – that reaches a net zero at 100% of hydrogen - the SMS ZeroFlame HY2 confirmed its high performance in terms of flame thermal profile and extra-low NOx emissions, and its high flexibility as it can operate in flame, flameless and over-boost mode at any percentage of hydrogen in the gas mixture. SMS ZeroFlame HY2 burner design was optimized with the help of Ansys computational fluid dynamics simulation software. The first set of burners was then tested in an experimental test furnace. Through this procedure, SMS was able to confirm the behavior of the burners and to experimentally validate the theoretical model. The first lot of SMS ZeroFlame HY2 burners will be installed and started up in the first half of 2023.

Alexander Spatzker, thyssenkrupp Steel Europe AG, Germany

Co-Author:
Hai-Thong Ho, thyssenkrupp Steel Europe AG
Andrej Johnen, thyssenkrupp Steel Europe AG
Markus Wischermann, thyssenkrupp Steel Europe AG

Abstract:
In times of energy crisis, shortage of natural gas and geopolitical challenges the constant supply of electrical energy presents a great obstacle. During the last years, prices for electricity and natural gas were under constant fluctuations and even stable energy supply for households cannot be guaranteed anymore. Recently blackout plans were developed for the worst cases.In integrated steel works, the blast furnace (BF) and the coking plant contribute to the energy network. Beside hot metal and slag, the top gas of the BF is used as an energy source for various processes e.g. heating of hot stoves, coking plant or hot rolling mills. Surplus amounts of gas are used in the nearby power plants to produce electrical and thermal energy for district heating of surrounding households. For tk SE the produced electric energy covers more than the consumption of the entire plant and supplies the surplus to the electrical grid. This raises the question if this surplus can be further increased to save other fossil resources and help the electrical grid in times of power shortages. A project has been started to investigate possible operating conditions to increase either the amount of top gas or the calorific value of the BF top gas. This paper will show the theoretical and practical results of this project and discuss advantages and disadvantages of these parameters.

Michael Alter, ALTER Blast Furnace Consulting, United States

Co-Author:
Andrii Moskalyna, ISI NASU
Bohdan Kornilov, ISI NASU
Oleksii Chaika, ISI NASU

Abstract:
For the last 100 years, trends and classification of blast furnaces blow-in have been discussed. Development of blow-in subdivided into 3 periods: 1st - continued until end of 30s of XX century, characterized by lack of scientific knowledge, mysticism and based on previous experiences; 2nd - until the beginning of 70s, when "traditional" blow-in technology was mastered with one problem - difficulties with opening first casts and simultaneously overheating top; 3rd period is in progress nowadays, it includes developments of new methods for intensifying heat transfer during blow-in and scientifically generalize blow-in techniques. Major objectives of blow-in are to bring the blast furnace to normal operation, observing safety rules, in a short time, without significant costs, and to protect blast furnace and auxiliary equipment for long-term productive operation. These objectives are closely related to design features of blast furnaces, including the cooling system, type of lining, and furnace sizes, which have steadily increased from less than 500m3 to 5600m3. Complexity of understanding the processes of burden column heating during blow-in period that forms a gas flow and cohesive zone in it is the reason for numerous discussions about rational blow-in techniques: methods for calculating and placing burden layers in a blast furnace, usage of various additives to hot blast (nitrogen, natural gas, blast furnace or coke oven gases, oxygen, steam, etc.), the rate of hot blast volume increasing, its temperature ramp up and pressure drops trend along the burden column. In addition, a potential usage of wood in the blow-in burden, installation of narrowing rings into tuyeres or plug part of tuyere for blow-in are discussed. Recommendations for blast furnaces blow-ins and comparison of "Traditional" blow-in vs. "Progressive" and blow-in with nitrogen, developed by ISI NASU, is presented.

Reinoud van Laar, Danieli Corus B.V, Netherlands

Co-Author:
Peter Klut, Danieli Corus B.V
Victor Van Straaten, Danieli Corus B.V
Bart De Graaff, Danieli Corus B.V

Abstract:
Conversion of BF and BOF to DRP and EAF to reduce industrial CO2 emissions disguises the fact that BF technology is very efficient and economical and isn’t constrained by the availability and prices of scrap, DR-grade pellets, natural gas and hydrogen. It is therefore important to continue BF plant engineering and technological developments. This paper will address recent developments in our modern BF plant engineering and technology, which will be included in current projects in India. These include modern hydraulic top charging, dome combustion, dry gas cleaning system, alternative fuel and automation level II process control systems, but also allowances for future shaft injection to minimize CO2 emissions.

Shungo Natsui, Tohoku University, Japan

Co-Author:
Mizuki Tanaka, Tohoku University
Ryusho Honda, Tohoku University
Andrey Stephan Siahaan, Tohoku University
Hiroshi Nogami, Tohoku University

Abstract:
A numerical model of sintered iron ore deformation during ironmaking blast furnace processes helps to achieve superior process operations, particularly with the current goal of decarbonization. In this study, the high-temperature softening behavior of sintered iron ore characterized by a low-melting-point molten slag core and solid iron-rich phase shell structure was modeled using the Bingham plastic fluid model with an additional structural force that expresses the stiffness. The shape matching (SM) method was incorporated into the framework of the smoothed particle hydrodynamics (SPH) method, the stiffness parameter in the SM scheme was varied, and consistency with experimentally observed results was confirmed. The model was verified by comparing the simulated and experimentally determined 3D shape of sintered ore particles with different reduction rates after heating to various temperatures from 1473 to 1673 K. Furthermore, case studies simulating the softening and melting of the sintered ore particle bed in the cohesive zone were performed. We can expand this model's applicable range by experimental investigation of the effect of the composition of various types of ores on deformation behavior, and the mixing effect of various ores on bed deformation behavior could be clarified in detail.

Özgür Aslan, Erdemir Oyak Mining Metalluryg Turkey, Turkey

Co-Author:
Aytaç Altan, Zonguldak Bulent Ecevit University
Rıfat Hacıoğlu, Zonguldak Bulent Ecevit University

Abstract:
Pulverized coal injection (PCI) plants play significant role in reducing the blast furnace total energy consumption. Injecting desired amount of pulverized coal to a blast furnace is important not only for energy saving but also for process health. Pulverized coal injection rates from a PCI plant to a blast furnace is automatically controlled by logical algorithms and PID controllers of the automation system libraries. Since industrial plants do not have exact mathematical model, parameters of PID controller are determined according to the system dynamic response observed as a result of the experimental tests. Due to the system dynamics changes by time, the controller can not provide desired proves variable and parameters of PID controller need to be re-configured. Model reference adaptive controllers (MRAC) are used in many industrial applications in which the mathematical model of the system is unknown and the dynamic response of the system is changing over time. In this study, MIT and Lyapunov based model reference adaptive controller is applied in a pulverized coal injection tank pressure control system of a PCI facility, which is the critical process ironmaking energy consumption. In addition, fuzzy based adaptation gain regulation is proposed to improve MRAC performance. Adaptation speed and performance of MRAC is analyzed under disturbance effect. Control performance results of fuzzy based gain regulation MRAC is compared with PID controller and It is observed that MRAC shows better performance.

Bharath Rangavittal, KTH Royal Institute of Technology , Sweden

Co-Author:
Michael Vynnycky, University of Limerick
Björn Glaser, KTH Royal Institute of Technology

Abstract:
Development of mathematical models which include complex multiphase flow, coupled with heat exchange and chemical reactions, is necessary for understanding the inner state of the blast furnace. In this work, a novel approach using asymptotic methods is developed to model the transient gas-solid flow behaviour in the blast furnace. This is done by reducing the earlier developed Euler-Euler models with scaling assumptions that are based on the fact that the residence time of gas in the blast furnace is usually smaller than that of solid by several orders of magnitude. Results from this reduced model yield gas and solid flow patterns inside the blast furnace. In parallel, another model is developed by combining Discrete Element Method (DEM) and Computation Fluid Dynamics (CFD) to precisely simulate the gas flow and solid motion in the blast furnace. A qualitative comparative study between velocity patterns obtained from both the models is carried out. It is believed that asymptotic modelling could possibly open the doors to a computationally efficient approach for predicting the inner state of the blast furnace.

Horst Hill, Deutsche Edelstahlwerke Specialty Steel GmbH & Co. KG, Germany

Co-Author:
Frank van Soest, Deutsche Edelstahlwerke Specialty Steel GmbH & Co. KG
Hans-Günter Krull, Deutsche Edelstahlwerke Specialty Steel GmbH & Co. KG
Andreas Mohr, Deutsche Edelstahlwerke Specialty Steel GmbH & Co. KG

Abstract:
Additive manufacturing technologies like the laser powder bed fusion (LPBF) process are used in various industrial applications. The advantages like a possible complex shaped geometry or small lot sizes offers a high degree in freedom, for products as well as for research and development topics. But, in most cases materials with a low amount of carbon like the 1.4404 are used for LPBF. This material exhibits and easy processing with LPBF, but these kind of materials are not suitable for tooling applications. Tool steels like 1.2343 or 1.2344 offer a higher hardness and wear resistance, but the defect-free processing is complicated. And in addition, the small lot sizes of the different AM-processes are also a drawback for this technology. Especially regarding a scale-up to a mass-production with focus on tooling. Therefore, the aim of this paper is to identify chemical compositions that provides both: a good processing with LPBF and steel shop together with properties like wear resistance. This covers the whole life-time of a part, beginning from prototyping, to mass production and finally, spare-part production

Andreas Mohr, Deutsche Edelstahlwerke Specialty Steel GmbH & Co. KG, Germany

Co-Author:
Janosch Conrads, Deutsche Edelstahlwerke Specialty Steel GmbH & Co. KG
Karlheinz Hoeren, Deutsche Edelstahlwerke Specialty Steel GmbH & Co. KG
Horst Hill, Deutsche Edelstahlwerke Specialty Steel GmbH & Co. KG

Abstract:
Additive manufacturing offers the possibility of producing geometrically complex components that cannot be manufactured by conventional machining routes. Due to this advantage, additive manufacturing is already being used in many fields of application such as medical technology or aviation. In general tooling for example, additive manufacturing can be used to realize optimized cooling channels, which can increase the production rate. However, there is currently a lack of tool steels that can be processed crack-free via additive manufacturing. As a result of their good processability, maraging steels such as 1.2709 have established as tool steels for additive manufacturing. These steels however are free from carbides, which results in lower wear properties than typical carbon tool steels. In the present work, it is shown how the tool steel 1.2083 can be optimized for use in additive manufacturing by an adapted chemical composition. The developed alloy can be easily processed in the Laser Powder Bed Fusion process and offers a hardness of 53 HRC already in the as-built condition. Furthermore, the tempering behavior is identical to that of 1.2083. Thus it is possible to produce additively manufactured components with properties comparable to a conventional carbon tool steel in mold making.

Tobias Brune, SMS group, Germany

Co-Author:
Yannik Wilkens, SMS group
Peter Weiland, SMS group

Abstract:
SMS group supplies plant technology for the production of high-quality metal powder for Additive Manufacturing (AM) and other technologies. Cost-effective and high-quality powders will be one of the main drivers for the development of metal AM towards a sustainable industrial technology. By operating a gas atomization plant (VIGA - Vacuum Induction Gas Atomization) integrated in the SMS 3D-Test Center, the SMS group has optimized the classical powder production for the requirements in AM over the last years. In addition to conventional gas atomization plants, the SMS group, together with a customer, has developed another innovative powder production process. The conventional batch-wise process is transformed into a continuous process. The continuous powder production plant enables cost-effective and large-scale production of up to 4,000 tons per year. Compared to the traditional gas atomization process the capacity is increased by a multiple. Production costs for spherical, high-quality metal powders are significantly reduced. The increase in capacity results in enormous economies of scale. Set-up times, melting and cooling times are reduced. In the new process developed by SMS group, two Vacuum Induction Melting (VIM) furnaces continuously hold liquid melt, which is atomized successively through the nozzle. The nozzle can be exchanged during operation. Melting is done under vacuum to guarantee highest quality levels like in the conventional process. In addition to the VIM route, where pure scrap is used as feedstock, the new process can also work with an existing liquid material supply. A metallurgical route with basic scrap as feedstock is also possible.

Yuriy Lytvynyuk, Elkem ASA, Norway

Co-Author:
Antonio De Pretto , Elkem
Bjørnar Larsen, Elkem

Abstract:
A transition of the steelmaking industry towards the green steel making and the reduction of CO2 emissions includes the substitution of the blast furnace route of pig iron production by melting of the Direct Reduced Iron (DRI) in electric furnaces, typically employed in ferroalloy smelting. Two types of furnace designs are presently offered by engineering companies, which operate in either an immersed electrode or brush arc mode configuration, but all of them are based on the application of Søderberg electrodes. Elkem Carbon Solutions, as the inventor of the Søderberg electrode technology, has over a century of experience in the operation of Søderberg electrodes in various pyrometallurgical processes and diverse configurations of electric furnaces. This paper provides an overview of the current features and latest trends in Søderberg electrodes, and their application within ferroalloy smelting, with a focus on the electrode operation under similar conditions to those envisaged for DRI smelters.

Mohammed Alzayer, SABIC, Saudi Arabia

Co-Author:
Mohamed Bahgat Saddik, SABIC

Abstract:
As indicated by the principles of green chemistry, synthesis of materials must be done in a way that avoids hazards. One of the challenges in producing DRI (direct reduced iron) in shaft furnace reactors is ignition of the DRI pellets after discharge. In this study, the oxidation behavior of DRI pellets was examined using different sources of raw iron ore. Each type was reduced in lab using different conditions of reduction temperatures, reducing gas compositions, and pellets’ sizes. After generating reduction curves and comparing the reduction behavior of these pellets, they were exposed to severe oxidizing environment in order to compare how each condition responds to oxidation.

Julia Fogelström, Swerim AB, Sweden

Co-Author:
Du Sichen, Hybrit Development AB

Abstract:
Direct reduction of iron ore using hydrogen is one process that can produce iron from virgin materials and at the same time reduce CO2 emissions. In a shaft furnace, iron ore pellets are loaded at the top while hydrogen is introduced at the lower part. Pellets are slowly passing through the reactor and experience a temperature gradient ranging from low to high, i.e., non-isothermal reduction. Only a handful of studies have been performed to investigate the effect of non-isothermal reduction, and none focus on systematic analysis. Very few comparisons between isothermal and non-isothermal reductions have been made. To better understand the kinetics of non-isothermal reduction for process optimization, a preliminary study including both non-isothermal and isothermal experiments using pure hydrogen is conducted. The reduction experiments are performed in a resistance-heated furnace at 1173 K or between 723-1173 K for the isothermal and non-isothermal experiments, respectively. Non-isothermal reduction is much slower than isothermal reduction, as expected. The heating rate greatly affects the reduction rate, increasing with increasing heating rate. The mechanisms during the isothermal and non-isothermal reductions are discussed and compared. The reduction rate slows down at the later stage of reduction. At this point, the non-isothermal reduction rate is lower compared to isothermal reduction. To further examine the effect of heating rates, the microstructure of reduced samples is studied using a scanning electron microscope. The microstructure develops over time as the pellet is reduced, this is true for both isothermal and non-isothermal reduction. The heating rates have a limited effect on the microstructure. It would be difficult to capture and model the reduction behavior using only isothermal reduction experiments. Thus, studying non-isothermal reduction is needed. When optimizing the reduction in a shaft furnace, considerable attention should be directed toward the effect of the heating rates.

Oscar Hessling, Swerim AB, Sweden

Co-Author:
Du Sichen, Hybrit Development AB
Niklas Kojola, Hybrit Development AB
Julia Brännberg Fogelström, Swerim AB
Johan Martinsson, Swerim AB

Abstract:
Hydrogen reduction of iron ore, to reduce carbon emissions in the steel industry, is a plausible way forward as focus on fossil free production increase. The CO2 byproduct, generated by carbon reduction, is negated and replaced with H2O. In a Hydrogen Direct Reduction shaft, both temperature and pH2O will vary over the shaft height. Lower temperature and higher pH2O found at the top. The reduction reaction with hydrogen is highly dependent on the temperature and pH2/pH2O ratio. Lower temperature and higher pH2O would result in a lower reduction rate. Since only a few systematic studies have been conducted, this work aims to study the effect of pH2O over a temperature range relevant to industrial practice. A resistance heated furnace and a water vapor generator is employed to investigate the 0-15% pH2O range, in the 600 °C – 900 °C temperature range. To produce reliable data, the water content in the gas must be accurately controlled. A system is carefully designed to ensure precise control of the water content in the reaction gas. To further the industrial context, industrially produced iron ore pellets are utilized. Thermal Gravimetric Analysis (TGA) is used to follow the reduction. To understand the reaction mechanisms, SEM is used to study the microstructure of partially reduced pellets. Results suggest the reduction rate is profoundly affected by water at low temperatures, less so when the temperature is increased. The microstructure is highly affected by pH2O at 600 °C, at higher temperatures the microstructure is largely unaffected. Reaction mechanisms are discussed based on the reduction curves and micrographs. The impacts of gas dilution and chemical reaction rate are evaluated.

Theresa Overbeck, VDEh-Betriebsforschungsinstitut GmbH, Germany

Co-Author:
Gregor D. Wehinger, Clausthal University of Technology
Martin Kutscherauer, Clausthal University of Technology
Michael Hensmann, VDEh-Betriebsforschungsinstitut GmbH

Abstract:
Increasing the use of hydrogen as reducing gas in direct reduction changes the reaction and operating conditions of the plant. Particle resolved computational fluid dynamics (PRCFD) offer insights into the surrounding gas flow and the reaction-diffusion mechanisms inside each pellet. As a first step, in this work a three-dimensional model of a single porous iron ore pellet is developed. The model represents the pore diffusion and internal stepwise reduction reactions from iron(III)-oxide to iron with hydrogen and carbon monoxide. The reactions are implemented in the gas and solid species and energy conservation equations. The model is flexible regarding the operating conditions (e.g. temperature), the initial pellet morphology, the initial gas and pellet composition and the gas composition at the pellet surface. The model allows the locally resolved investigation of the reduction progress inside a single porous iron oxide pellet. Radial differences in solid mass fractions go along with a varying porosity of the pellet. The influences of diffusion and reaction kinetics are investigated depending on temperature and gas and pellet composition. Especially, the diffusion of the produced water to the pellet surface can be a limiting factor and is further investigated. We will discuss these results with literature data and own analyzations of direct reduction pellets. In perspective, the model will be used for a PRCFD simulation of different reactor sections.

Noel Ladenthin, RWTH Aachen University , Germany

Co-Author:
Dieter Senk, RWTH Aachen University
Rongrong Wang, RWTH Aachen University
Hannes Drippe, RWTH Aachen University
Alexander Babich, RWTH Aachen University

Abstract:
In order to reduce CO2 emissions and make steel production more sustainable, many steel producers are currently planning to produce metallic iron for steel production using hydrogen-based direct reduction instead of carbon based reduction gas. Melting in electric arc furnaces demands low amounts of gangue in DRI to keep the slag volume low. In respect to this DR pellets with high iron concentration are required. On the other hand highly concentrated iron ore with increased basicity is less available compared to medium iron containing BF pellets with low basicity. IEHK at RWTH Aachen University is characterizing different BF-grade pellets and investigating the influence of texture on reducibility using hydrogen. The characterization is carried out with the aid of chemical analyses of the composition and investigations of the microstructure by microscopy. The reducibility of individual BF-grade pellets is studied in a laboratory furnace using different hydrogen concentrations. In addition, direct reduction tests were carried out using a test plant with a capacity of approx. 20 kg of iron ore pellets. This allows the consideration of mechanisms that may be observed in the reduction of a bulk but not in individual pellets and allows use for upscaling considerations. The results of the investigation can be applied to design further direct reduction processes with low-grade iron ore pellets.

Aidin Heidari, University of Oulu, Finland

Co-Author:
Timo Fabritius, University of Oulu
Mikko Iljana, University of Oulu

Abstract:
The study aimed to compare the reduction behavior of DRI (direct reduced iron) and blast furnace pellets in a CO-H2 atmosphere. The experiments were conducted under controlled conditions to evaluate the effect of temperature and CO-H2 ratio on the reduction process. The reduction rate and final degree of reduction were used as the main parameters to compare the performance of DRI and blast furnace pellets. The results showed that the reduction rate of DRI was much faster than that of blast furnace pellets, and the final degree of reduction was also higher for DRI. This can be attributed to the higher reactivity and porosity of DRI, which facilitates the transfer of gaseous reduction agents and results in a more complete reduction process. The study also found that increasing the temperature and CO-H2 ratio improved the reduction rate for both DRI and blast furnace pellets. However, DRI still showed better reduction performance compared to blast furnace pellets under all experimental conditions. The comparison of the reduction behavior of DRI and blast furnace pellets in a CO-H2 atmosphere highlights the advantages of using DRI as a raw material in the iron and steel industry. The results of this study demonstrate that DRI is a more favorable alternative to blast furnace pellets in the CO-H2 reduction process due to its higher reactivity, porosity, and reduction rate. The findings of this study can help optimize the reduction process and improve efficiency and could have important implications for the iron and steel industry, particularly for the production of high-quality steel products.

Breno Maia, Lumar Metals, Brazil

Abstract:
The practice of Slagplashing is already consolidated industrially. However, there are still uncertainties about the relationship of the boom parameters and their effects on the slag. This article presents a comparison of the similarity of two 300t converters, one in Ukraine and the other in Brazil, with the 1/10 scale acrylic model of the LASIP located at the Federal University of Minas Gerais and their respective slagsplashing patterns. The results will be compared using an improved version of the equation of motion in determining the jet penetration over the slag layer and the ejection of material to cover the refractory walls.

Bernhard Mitas, K1-MET GmbH , Austria

Co-Author:
Ville Visuri, University of Oulu
Johannes Schenk, Montanuniversität Leoben

Abstract:
The significance of iron droplets dispersed in BOF slag is researched regarding their contribution to overall refining kinetics. The droplet generation in the hot spot vicinity and their behaviour during their residence in the slag is modelled. Previously the consensus has been to focus on fine droplet dispersion when modelling BOF emulsion refining processes. This research indicates that the focus should be on mass transfer between the larger droplets and the slag when modelling emulsion refining.

Xiaomeng Zhang, K1-MET GmbH, Austria

Co-Author:
Stefan Pirker, Johannes Kepler University
Mahdi Saeedipour, Johannes Kepler University

Abstract:
Inclusion removal via slag absorption is considered a common way of lowering the inclusion amount in steel melt. However, the stage of inclusion separation at the steel-slag interface and further integration into the slag has been overlooked, leading to an overestimated inclusion removal efficiency. The current work conducts numerical simulations to investigate the interactions between a micron-sized spherical particle and steel-slag interfaces. By using the volume of fluid (VOF) method in combination with the dynamic overset mesh, this study is able to visualize the separation process, including the formation and evolution of a meniscus due to the wetting property of the system and the resulting capillary force-driven particle motion. The results indicate that the wetting angle and slag viscosity govern the interfacial separation. The role of capillary force is closely associated with the meniscus shape. It mainly acts as a driving force for particle motion arising from a decurved meniscus attached to the particle. It also imposes resistance when the meniscus is upcurved in the later stage of particle separation. In a low-viscosity environment, the positive capillary force results in significant particle acceleration and high enough particle displacement, thus separating the particle into the upper fluid. Whereas with the resistance from high viscous slag, no complete separation is observed, which corresponds to most situations in realistic steel-slag systems. It concludes that the dissolution of the particle happens near the steel-slag interface. Further, the effect of the dissolution-induced dynamic interfacial phenomenon, i.e., the Marangoni convection, is discussed. This study provides insight into the physics of inclusion removal at the interface which is essential for steel quality control.

Elizaveta Cheremisina, K1-MET GmbH, Austria

Co-Author:
Johannes Schenk, Montanuniversität Leoben
Emmanuel de Bilbao, CNRS, CEMHTI, University of Orleans
Zheng Zhang, CNRS, CEMHTI, University of Orleans

Abstract:
Density, surface tension and viscosity of the slag are key properties in steel refining. The accurate measurement of these properties is required for better process control of metallurgical operations. Aerodynamic levitation was employed to derive density, surface tension and viscosity of CaO-SiO2 and CaO-SiO2-Fe2O3 slags under contactless conditions. The levitation experiment was carried out under mixture of argon (80%) and oxygen (20%) gas atmosphere in the temperature range between 800 °C and 2000 °C for the density and 1500 °C and 2000 °C for surface tension and viscosity measurements. The quenched slag samples were analysed by Raman spectroscopy to provide information on the anionic structure of the silicate slag. It was observed that the addition of Fe2O3 to the silicate did not affect surface tension, while it influenced the density due to the reduction of non-bridging oxygens and viscosity due to the increase in the polymerization degree, especially for high silica-containing slag.

Jelena Brankov, Carmeuse SA, Belgium

Co-Author:
Dana Baricova, Technical University of Košice
Peter Demeter, Technical University of Košice
Jaroslav Legemza, Technical University of Košice
Róbert Findorák, Technical University of Košice
Branislav Buľko, Technical University of Košice
Sorinel Nafornita, Carmeuse SA
Francois Ponchon, Carmeuse SA

Abstract:
An ultimate goal of oxygen steelmaking process is formation of a basic slag using fluxes (lime, dolime) to remove impurities, like phosphorus and sulphur. Fluxes dissolution efficiency is important to achieve basic slag at the early stage of the process and protection of refractory lining. Limiting step in the slag formation process in the BOF represents lime dissolution kinetics in the primary acidic slag. Lime for the steelmaking process must be soft-burnt, as only this type has a high reactivity - ability to transition to the slag phase. Experimental work was carried out in a Marsh furnace to determine the mechanism of lime dissolution in the slag. Dissolution rate of different types of lime (soft, medium, and hard-burnt lime) in the typical BOF slag were compared. It has proven an excellent solubility for the soft-burnt lime, which is related to its high reactivity and a lower solubility for the hard-burnt lime. After determining the mechanism of lime dissolution in the steel slag, high-temperature experiments were performed in the induction furnace. Results were used to quantify the level of lime dissolution in the steel slag, compare it with a standard lime reactivity measurement, and for development of Value in Use Model. This in-depth study was conducted to understand the importance and to evaluate the influence of lime characteristics on BOF steelmaking process and their quantification through total cost of ownership. Besides lime dissolution, thermodynamic and the fluid dynamic approach was used, together with mass and heat balance. Value in Use Model proves the importance of lime characteristics and its impact on steel cleanliness, metallurgical results, productivity, and total cost of steel production including notably energy and CO2 balance. Model can calculate the savings and cost benefits for a given inputs, including lime and dolime,and operating parameters for respected case.

Oleksandr Kharchenko, Zaporizhzhia National University, Ukraine

Co-Author:
Oleksiy Smirnov, National Academy of Sciences of Ukraine
Olena Volkova, Iron and Steel Institute, TU Bergakademie Freiberg

Abstract:
The work is devoted to the analysis of physical and chemical processes in the high-temperature reaction zone (HTRZ), which is formed in steelmaking processes with oxygen blowing, such as converter production. Detailed thermodynamic analysis of HTRZ has been conducted, and parameters of liquid steel bath HTRZ have been determined: temperature, masses and chemical composition of metal, slag and gas phases. It is concluded that the carbon contained in the metal of HTRZ behaves as a catalyst for the transition of the iron into the gas phase and, accordingly, the irrevocable loss of iron in the steelmaking process. The results of the study allowed to build previously unknown fragments of equilibrium phase diagrams of the high-temperature region of systems "iron-oxygen" and «iron-oxygen-carbon». Another aspect of this study is removal of impurities from HTRZ. It is important process in which chemical elements are irretrievably removed from the space of the steelmaking unit. According to the temperature and the degree of removal into the gas phase, studied impurities can be divided into three groups: a) carbon, which is almost completely removed at a relatively low total oxygen content in the HTRZ and temperatures up to 2000°C; b) silicon, calcium, magnesium and phosphorus, which are almost completely removed into the gas phase in the temperature range of 2100...2800°C; c) manganese, sulfur, iron and aluminum, which are partially removed at temperatures above 2600°C. With an increase in the total oxygen content in the HTRZ above 15%, temperature increase sharply slows down, reaching limit of 2900°C at a total oxygen content of 20%. In this case, iron intensively escapes into the gas phase along with impurities. Therefore, blowing the steelmaking bath with oxygen at a very high rate is inappropriate, since it does not lead to a significant increase in the productivity of steelmaking unit.

Sourav Kumar Panda, Tata Steel IJmuiden B.V., Netherlands

Co-Author:
Aart Overbosch, Tata Steel Nederland Technology B.V

Abstract:
Lime is added during the converter process to remove phosphorus from steel. At the end of the converter process, some heats were found to contain undissolved lime, especially, the low phosphorous aim grades. The undissolved lime issue can be due to insufficient time after flux additions before the slag is tapped, formation of C3S/C2S layer on top of CaO flux which prevents further dissolution, and flux reach saturation limit which prevents further dissolution. One way to increase the lime dissolution is to increase the FeO content locally during the converter process. Dolomite is also added to the converter slag to control the MgO-C refractory dissolution by aiming right MgO-saturation level. Thermodynamic studies were performed using FactSage to determine “minimum FeO” content required within the converter slag which dissolves all lime that is added during the process. And, to determine the “minimum MgO” content required during converter slag to reach the MgO saturation level. The assumption in the current work is the fast kinetics of transfer of solid lime and dolomite to liquid slag when fluxes are added. FactSage-Macro function was used for determining the lime and MgO saturation limit for ~15,000 synthetic slag compositions within a specific range of composition and temperature. Regression formulas was then developed using the FactSage calculations which can calculate the “minimum FeO” and “minimum MgO” content for any given slag composition and temperature within that range. The formula will help design the local slag composition to avoid the undissolved lime issue and MgO-saturation level of the converter process.

Paulo Hopperdizel, Lumar Metals, Brazil

Co-Author:
Paulo Hopperdizel, Lumar Metals
Atul Dubey, Jindal Steel & Power Limited
Raju Psjkk, Lumar Metals

Abstract:
JSPL Angul is a integrated steel plant with the capacity to produce 6,000,000 tonnes of steel per year, located in the city of Angul, Odisha, India. Its industrial complex consists of a one Midrex direct reduction plant, with the capacity to produce 2 MILLION MT of Hot DRI / tonnes year, one Blast Furnace whith the capacity to produce 4 million MT of HotMetal / tonnes year, two melt shops, one meltshop with 1 electric arc furnaces of 250 tonnes, 1 ladle furnaces, 1 continuous casting and one melt shop with 1 BOF of 250 tonne 2 continuous casting and rolling mills. JSPL Angul during the hot commissioning of EAF meltshop worked with high amount of Hot Metal charged (around 85%), completing the charge with DRI (around 15%), for this mix of charge only chemical energy is required, and the efficiency of oxygen injectors instaled at EAF were not able to reach the performance required by JSPL Angul in these cases. The injectors installed not allow the use of all injector in the early moments of process, due high FeO generation, high height of foaming slag and slopping of slag through slag door. Due this, JSPL Angul planned the revamp of the chemical power package of EAF with the aim of reducing oxygen blow time and have high metallic yield of the heat. This work will present the equipment used, the concepts used in the remodeling project of the chemical package, as well as some of the results obtained after the implementation of this new equipment.

Gerald Hohenbichler, Primetals Technologies Austria, Austria

Co-Author:
Manuel Sattler, Primetals Technologies Austria
Wolfgang Wichert, Lech-Stahlwerke GmbH

Abstract:
Electric Arc Furnaces have always been the core plant and core process of Minimills, all over the world, because an EAF is THE scrap-based process of steelmaking. And it has always been a rather cheap production step as being based on electricity and not too complex, since the base material is already steel. The challenge however is to optimize the melting process, irrespective of the input material mix - and this is the biggest pain for most steel producers - for any type of target steel grade, as well as irrespective of the shift team, of the furnace lining, of environmental prescriptions and so on. Primetals Technologies has developed the Heat Cloning App, a preferred cloud based digital system to assure such operational optimization, using the real Level2 and Level 1 data of the EAF, hence using the real historical data of an EAF plant. Optimization objectives are stable tap-to-tap times, charge temperatures adapted to the needed overheating for the ladle furnace or the VOD and for the casting operations, and last not least the minimum operating cost. More than ever minimizing electrical energy per ton of liquid steel and minimizing the total amount of required specific energy are typical optimization objectives as well. Real data are showing that 5 - 10% better operations, reduced cost, higher margins are achievable by using Primetals' Heat Cloning App.

Jaemin Lee, Hyundai Steel Co. , Korea, Republic of

Co-Author:
Joohyun Park, Hanyang University
Jongoh Jo, Hyundai Steel Co.
Daehoon Shin, Hyundai Steel Co.

Abstract:
In these day, Carbon Neutrality is important issue in the world. And iron&steelmaking industry is also undergoing process change to achieve carbon neutrality. The biggest change is process transitions from BF-BOF to DRI-EAF. In case of BF-BOF process, They can produce from normal grade of steel to AHSS grade steel. But this process need to generate a plenty of CO2 emission, 1.85tCO2/steel ton.[1,2]. On the other hands, DRI-EAF process is also possible to produce from normal to AHSS, But this process CO2 emission is just half of BF-BOF, 0.97tCO2/steel ton. In other words, producing steel using an EAF is more effective in terms of CO2 emission compared to BF-BOF process. And by using DRI in EAF, They are able to produce high grade steel. EAF technology is developing from 1968 to 2010 in the direction of saving EAF energy consumption. The use of industrial wastes in EAF technology is important part in terms of diversifying raw materials for EAF in the future, and this technology can meet another jump up in saving EAF energy consumption. And using industrial wastes also decrease CO2 emission. In this study, I share some case of using industrial wastes in EAF especially Al dross. In case of Al dross, we put the Al dross in EAF with Fe powder and Na2CO3. Fe powder aim to increase density of Al dross product and Na2CO3 is for stabilizing P2O5 activity coefficient in slag. In this paper, we share our experience of using industrial waste in EAF and we also share our future works related to use wastes.

Doug Zuliani, Tenova Goodfellow Inc., Canada

Co-Author:
Babak Babaei, Tenova Goodfellow Inc.

Abstract:
Water Leaks represent a serious concern in EAF steelmaking for both. This paper describes a comprehensive Water Leak Mitigation Technology package designed to solve the EAF water leak problem. This technology can be installed as a complete package or as separate independent parts in tune with individual steel plant priorities and includes cooling panel designs to minimize the impact of leaks; three technology options to rapidly detect and alarm when a water leak occurs; inspection technology to safely determine the location & severity of the leak; and finally, mitigation technology to safely turn-off water flow to the damaged panel. This paper will discuss each of the above technologies and make reference to actual plant confirmatory results.

Emmanuel Placier, AMI Automation, Czech Republic

Co-Author:
Emmanuel Placier, AMI Automation
Saul Gonzalez, AMI Automation
Jesus Andrade, AMI Automation

Abstract:
Since the introduction of Off Gas analysis instrumentation in the Electric Arc Furnace, different applications have been developed using this information to improve the process efficiency and safety. Using the CO, CO2, temperature, and flow of the gas, the AMI SmartFurnace modules for Chemical Energy optimization calculate the optimal setpoints of the EAF burners and lances. The chemical energy modules are complemented dynamic process models and algorithms for electrical energy providing an integral furnace control of the Oxygen, Natural Gas, and Carbon Injection, as well as continuous raw material feeding. Using artificial intelligence, the Abnormal Water Vapor Detection module uses the gas temperature, flow, and water vapor content to identify unexpected sources of water in the off-gas which could pose a potential safety hazard, distinguishing it from the normal amount of water present in the furnace environment. Finally, the efforts to reduce emissions in the steel industry require accurate and reliable measurements of CO2. Understanding the influence of different conditions such as raw materials, melting profiles and practices, plays a major role in defining strategies to lower the environmental impact of the production. The latest implementations of this technology in plants with a wide range of raw materials, EAF mechanical characteristics, and production needs are described in this paper, and the achieved results.

Georg Gaiser, Montanuniversität Leoben, Austria

Co-Author:
Peter Presoly, Montanuniversität Leoben
Christian Bernhard, Montanuniversität Leoben

Abstract:
Reducing CO2 emissions in steel production is one of the major challenges for the European steel industry in the upcoming years, whereby the remelting of scrap in electric arc furnaces is the most important bridging technology. Depending on the scrap type, steel scrap contains different levels of undesirable by-elements, also referred to as tramp elements. Technical and economic limitations lead to non-negligible tramp element contents in the steel. Those can affect high-temperature oxidation mechanisms in casting, rolling and annealing processes, leading to various types of internal oxidation phenomena and the formation of (liquid) phases at the interface. Within the scope of the present publication, oxidation experiments for different steels containing tramp elements were performed by means of thermogravimetric analyses. The influence of several time-temperature cycles and atmospheres were analysed. Particularly noteworthy are the experiments with an oxidation atmosphere simultaneously consisting of synthetic air and water vapour. In the presence of water vapour, oxidation intensifies, leading to a higher accumulation and formation of metallic copper phases at the interface and along grain boundaries. The results provide meaningful data to improve the understanding of high-temperature oxidation mechanisms in steel processing with a particular focus on continuous casting and serve as a basis for further experiments.

Minjoo Lee, Hanyang University, Korea, Republic of

Co-Author:
Jongoh Jo, Hyundai Steel Co.
Joohyun Park, Hanyang University

Abstract:
In order to reduce CO2 gas emission, steel companies are trying to develop the EAF steelmaking process instead of BF(–BOF) route by employing high amounts of DRI/HBI. DRI/HBI as a substitute for virgin scrap in EAF have been used because DRI/HBI does not have tramp elements. Unfortunately, however, commercially available DRI contains a relatively high level of phosphorus, which adversely affects the properties of steels. Although the previous studies on melting and phosphorus removal behavior in an EAF process involving partial use of DRI/HBI in conjunction with virgin scrap have been studied, the melting and dephosphorization behavior in EAF process conditions employing the 100% DRI/HBI have been less frequently investigated. Hence, we observed the morphology and distribution of elements with gangue oxides in HBI and investigated the phenomena occurred in EAF process using fully HBI as an alternative iron source using a high-frequency induction furnace at 1550oC. Main composition on gangue oxide in HBI was SiO2, Al2O3, and CaO in conjunction with unreduced iron oxide. Various size distribution of SiO2-(Al2O3-CaO) particles were entrapped in reduced iron matrix as well as in unreduced iron oxide phase. Small amount of siliceous slag was formed when HBI was melted, thus, phosphorus content in steel was not varied during the melting stage. This is possibly due to the formation of relatively acidic slag chemistry. To increase the dephosphorization efficiency, the distribution ratio of phosphorus between metal and slag was calculated using FactSage software by adding CaO in the furnace. The distribution ratio of phosphorus increases by adding CaO up to about 50% beyond which the melting point of slag is over 1500oC. So, the optimization of CaO content in the slag are required not only for maximum dephosphorization efficiency with good foamability but also for minimum slag volume with less refractory corrosion.

Joar Huss, Swerim AB , Sweden

Co-Author:
Du Sichen, Hybrit Development AB
Niklas Kojola, Hybrit Development AB

Abstract:
Phosphate capacity data has been used by steelmakers for many decades to optimize the dephosphorization praxis in various reactors, e.g. the BOF and the EAF. The data is commonly gathered in a laboratory where the partial pressure of oxygen can differ significantly from the industry. The use of this data in the industrial case requires careful consideration. For slag systems containing multivalent slag species, e.g. Fe and Cr, the slag structure will be dependent on the valence state of the ions. This will lead to a variation in the thermochemical properties with the oxygen potential. For instance, the presence of Fe+2 and Fe3+ could lead to a substantial dependence of the phosphate capacity on the oxygen potential. To illustrate the effect of oxygen potential on the phosphate capacity, experiments were carried out in a resistance heated furnace at 1873K. In the experiments, vanadium oxide was used as the multivalent species, to limit the reaction with the crucible. The phosphorus partition between liquid copper and a fully liquid, MgO-saturated, SiO2-MgO-VyOx slag was determined at different oxygen potentials in a controlled atmosphere. To set oxygen potential in the system (1.72 × 10-8 – 1.73 × 10-11 atm), CO-CO2 mixtures were used. The resulting phosphate capacity change one order of magnitude over the investigated oxygen potential range. Based on the present results, the applicability of phosphate capacity data gathered at a different oxygen potential than the prevailing in an industrial process is questionable. In effect the data could even mislead the engineer in its implementation. This is especially the case considering that the oxygen potential in the reactor slag varies with position and even time. Using phosphate capacity data for the process should as such be done cautiously even if the data is gathered at a relevant oxygen potential.

Bernhard Voraberger, Primetals Technologies Austria, Austria

Co-Author:
Hagen Fuchs, Primetals Technologies Germany
Naci Arun, Primetals Technologies Germany
Gerald Wimmer, Primetals Technologies Austria
Tilo Schulz, Primetals Technologies Austria
Willi Bühler, Primetals Technologies Germany
Andreas Viertauer, Primetals Technologies Austria

Abstract:
"The majority of worldwide steel production is still dominated by the integrated route via blast furnace (BF) and basic oxygen furnace (BOF). Due to rising costs for CO2 emissions as well as rising market requirements for green steel, the integrated steel plants are under pressure to reduce CO2 emissions drastically. The fact that the optimization potential for the coke-based blast furnace is limited, alternatives like increased scrap rate in BOF and especially DRI / scrap based electric steelmaking, which have a considerably lower CO2 footprint, are in the focus for green transition of the steel industry. The integration of an EAF into a brownfield plant is already challenging in respect to e.g. layout, logistics, productivity and environmental aspects; however, the fact that there are fundamental changes to the steelmaking and secondary metallurgy processes is often overseen. In this paper the differences between the two steel production routes via BOF and EAF including corresponding secondary metallurgy are described and compared regarding tramp elements (Cu, Sn etc.) as well as impurities (P, S, N). Limits, challenges and solutions for both routes will be explained for different charge mixes and final steel grade requirements. Special focus is given to demanding steel grades (IF, Si-grades, ULC automotive exposed) which have been mainly produced by converter steelmaking in the past and an outlook is given how to produce these grades via the EAF route in future. Finally recent references for secondary metallurgy will be presented."

Murat Günerdi, Çolakoglu Metalurji A.S., Turkey

Co-Author:
Andreas Fischer, Primetals Technologies Germany
Talip Kücük, Çolakoğlu Metalurji A.Ş.
Burhan Gündogan, Çolakoğlu Metalurji A.Ş.
Dincer Demircioglu, Çolakoğlu Metalurji A.Ş.
Naci Arun, Primetals Technologies Germany
Zafer Cetin, Primetals Technologies Germany

Abstract:
"As the request for ultra low carbon (ULC) steel and stainless steel is rising in the Turkish market, Colakoglu Metalurji A.S decided to increase the production capability for mentioned steel grades. Accordingly, the 300 tons capacity vacuum degassing (VD) plant was modernized by Primetals Technologies in 2020. In this paper, the modernization of the VD plant to the world's largest capacity vacuum oxygen degassing (VOD) plant will be explained. The 304L stainless steel production process and encountered problems with new equipment commissioned, updates of the automation and the level 2 systems will be described. As a result of this modernization work, the production of 304L was performed successfully in the VOD plant. The highest stainless steel heat size with 294 tons and the lowest Carbon level of 5 ppm in the world were achieved with the developed metallurgical patterns during the commissioning of VOD plant."

Barbara Costa Braga, Vallourec, United States

Co-Author:
Aurelien Fabas, Vallourec
Charles Delvaux, Vallourec
Michael Kan, Vallourec
Andre Assis, Vallourec

Abstract:
Steel cleanliness has become increasingly important throughout the years, bringing steelmaker’s attention to operational parameters that can optimize and fulfill these quality requirements. Argon stirring at the LMF is one of the key steps on achieving optimized steel cleanliness, especially if rinsing is performed before CaSi addition (pre-rinse). Trials were performed at Vallourec Star (Youngstown-Ohio) and heats were produced in 2 different scenarios: with and without pre-rinse. Lollipop samples analyzed on ASPEX demonstrates that pre-rinsed heats presented a strong drop on inclusion density (by -50%) when compared to heats that were not pre-rinsed (inclusion density stable). Pre-rinse practice was standardized at VStar.

Enzo Chiarullo, Tenova S.p.A., Italy

Co-Author:
Enrico Malfa, Tenova S.p.A.
Mattia Bissoli, Tenova S.p.A.
Sergio Porisiensi, Pittini S.p.A.
Marta Guzzon, Tenova S.p.A.
Marco Fulgosi, Pittini S.p.A.

Abstract:
Valorization of LF slag: the Pittini Group tests Tenova's air granulation process S. Porisiensi, M. Fulgosi – Ferriere Nord S.p.A. M.Guzzon, M.Bissoli, E.J.Chiarullo, E. Malfa - Tenova S.p.A. The Pittini Group has historically been active and committed to the reduction and valorization of steelshop residues and, in particular, Ferriere Nord plant in Osoppo was the first in Europe in 2000 to implement the recycling of LF slag by injecting it into EAF in lime replacement. In last two years, the Pittini Group tested, at Acciaierie di Verona and Ferriere Nord sites, an industrial-scale pilot plant for the valorization of the ladle furnace slag through an air granulation process developed and designed by Tenova S.p.A. Tenova developed a methodology for the design of dry slag granulation process based on Computational Fluid Dynamic modelling validated by the laboratory testing in a pilot plant. The present work shows the results of the dry slag granulation industrial testing, performed at Ferriere Nord plant, their consistency with the Tenova methodology in the process design together with validation through testing at laboratory scale pilot plant facility. In addition, the first study for the industrialization of the dry slag granulation process is presented, along with the various opportunities for valorization of the final product.

Alexander Schlemminger, QuantoLux Innovation GmbH, Germany

Abstract:
Energy consumption and refractories wear are the major cost drivers of ladle furnace treatment. In addition to factors such as the composition and temperature of the melt, these main cost factors depend strongly on duration of treatment. Long treatment times in particular, as they are common for extremely low Sulfur grade, can require a reheating of the melt. This is unfavorable in several respects. First of all, there can be no treatment work carried out during reheating. Therefore, the holding time of the melt in the ladle is prolonged. Secondly, compared to the EAF the absence of a foaming slag, leads to an overheating of the slag. This excessively hot slag now radiates a considerable amount of energy into the surrounding area, which downgrades energy efficiency. Thirdly, the very hot slag has a negative effect on especially the slag zone of the refractory lining, which has a particularly negative impact on the refractory service life. Precise process control based on in-situ slag analysis results can reliably avoid reheating and the associated unwanted effects. With the Laser Optical Emission Spectroscopy (Laser OES), an enhancement of the well-established spark OES, the physical homogenization of samples becomes obsolete. Instead, an immense amount of measurements allow a digital homogenization. Slag analysis times reduced by up to 90% allow significantly more slag samples to be taken and analyzed in-situ. Thus, the LF treatment can reach the required degree of desulfurization faster and more safely. In addition, the selection of a narrower process window, closer to the desirable optimum, leads to reduced lime consumption and fewer inclusions in the product. This reduces CO2 emissions and optimizes the use of resources.

Veit Humer, Primetals Technologies Austria, Austria

Co-Author:
Josef Watzinger, Primetals Technologies Austria
Michael Speher, Primetals Technologies Austria
Markus Nolan, Primetals Technologies Austria

Abstract:
Product quality, machine throughput and process safety are certainly the most important parameters in continuous casting. One crucial precondition to support those parameters is a stable mold level. If unstable, often non-uniform shell growth and casting powder inclusions occur. This can lead to various slab defects like cracks or bad slab surface quality. A totally new technology offers a proven solution in mold level stabilization: Unsteady bulging compensation via casting gap modification. Great results have been achieved in producing a very steady meniscus position and in the improvement of the mold flow conditions. This has an immediate effect on product quality. An analysis of production data and quality indicators like slab downgradings supports this statement. More specifically, all the data is put into relation to those quality defects and the results are compared to conditions with less performant mold level control.

Afranio Costa, Gerdau Acominas S.A. , Brazil

Co-Author:
Andre Nascimento, Gerdau Acominas S.A.
Gilberson Storck, Gerdau Acominas S.A.
Jose Maria Ibabe, Asseco CEIT a.s.
Gabrielly Oliveira, Universidade Federal de Minas Gerais
Antonio Gorni, Companhia Brasileira de Metalurgia e Mineração
Alisson Oliveira, NSigma Consulting
Gilberson Melo, Gerdau Acominas S.A.

Abstract:
Macro and microsegregation play an important role in understanding the solidification behavior of continuously cast steels. Both affects directly critical applications, which requires a higher degree of homogeneity since as cast stage. This study applied macro and micro approaches to perform a comprehensive characterization of the solidification microstructure of a slab with U-shape centerline segregation. In the macro-approach, a width-wise chemical analysis was performed using OES-PDA on whole centerline. Thickness-wise analysis was also implemented at 300 mm intervals in width direction. Carbon content in centerline was almost 3 times higher than at a point 37.5 mm below the surface. The same behavior happenned with P, S, Ti and Nb. The micro-approach in this study considered SDAS (Secondary Dendrite Arm Spacing) and second phase particles. Calculated figures presented very good correspondence with measured ones for both micro-approach features. Mushy zone was calculated using CON1D model and phase fraction was calculated both by CON1D and FactSage 8.2. NbC, TiN and MnS were the most relevant second phase particles calculated by Factsage. This finding matches to the analysis carried out by SEM-EDS. Based on these results, which measured values were in good agreement with calculated ones, it is possible to estimate the internal quality of slabs in a higher degree of confidence.

Gernot Hackl, RHI Magnesita GmbH, Austria

Co-Author:
Gerald Nitzl, RHI Magnesita GmbH
Wolfgang Fellner, RHI Magnesita GmbH

Abstract:
The quality of continuously cast steel is greatly influenced by the flow conditions in the mould, particularly at the meniscus, where the liquid steel is in direct contact with the casting flux. Stable conditions within a defined velocity range need to be achieved to avoid slag entrainment, one of the causes for product defects such as slivers on cold rolled sheets or defects on heavy plates, as well as an increasing breakout risk, due to uneven mould lubrication. Determination of the flow inside the mould therefore is an important aspect in order to assess the status of the system and derive possible measures for improvement, such as by the design of submerged entry nozzles. This paper presents the application of a method to continuously measure the sub meniscus velocity in the mould of slab casters using immersed paddles. Information about the velocity distribution as well as the general flow pattern trend and stability can be gathered. This goes beyond standard nail dipping tests, which typically only provide a snapshot but lack information about transient phenomena. In combination with modern simulation technology the described system can support general design optimization of refractory solutions for the continuous casting process and in particular provide criteria for tailor made customer solutions. Several examples are shown in this paper.

Johann Winkler, K1-MET GmbH, Austria

Co-Author:
Susanne Hahn, Primetals Technologies Austria
Sergiu Ilie, voestalpine Stahl GmbH
Christian Bernhard, Montanuniversität Leoben
Roman Krobath, voestalpine Wire Rod Austria GmbH

Abstract:
The in-situ bending test IMC-B provides the characterization of the crack sensitivity of steel after controlled solidification and subsequent cooling. The present study investigates the influence of varying cooling conditions on the surface defect sensitivity of low and medium carbon steel with 0.02-0.04 wt.-% Nb. Standard cooling as well as “soft cooling” and “hard cooling” strategies for slab casting are investigated. The results indicate a significantly higher crack sensitivity for hard cooling than the soft cooling strategy. The simulation of the corner temperature history also considerably shifts the ductility trough towards lower temperatures. The findings confirm the experience of slab casting operation. Finally, the bending test results and grain size measurement are applied for benchmarking the recently developed commercial defect monitoring tool for continuous casting, SQI. The results point to excellent correspondence and show the high potential of smart online quality prediction based on thermodynamics and process data for the future.

Matthias Taferner, Montanuniversität Leoben, Austria

Co-Author:
Daniel Kavic, Montanuniversität Leoben
Michael Bernhard, Montanuniversität Leoben
Julian Laschinger, K1-MET GmbH
Sergiu Ilie, voestalpine Stahl GmbH
Christian Bernhard, Montanuniversität Leoben
Michael Bernhard, Montanuniversität Leoben

Abstract:
Secondary cooling of the strand is one of the key issues in achieving the demanded surface quality in casting defect-sensitive steel grades. Numerous laboratory setups characterize heat transfer coefficients (HTC) between the air-mist cooling sprays and the strand surface. The recently developed nozzle measuring stand (NMS) at “Montanuniversitaet Leoben” provides the measurement of water distribution, impact pressure and local heat transfer coefficients for a wide variety of spray parameters. The quantification of these parameters in the overlap region between two sprays is a unique feature. The embedment of the NMS into an in-house developed 2D-FV-solidification simulation software called m²CAST provides the direct transformation of the measurements via a neural network-based HTC database towards surface temperature control in continuous casting (CC). The presentation will exemplify the influence of cooling parameters on the water distribution, impact pressure and local HTC. The spraying parameters include the distance between the nozzle and strand surface, the inter-distance of nozzles, the water flow rate, and air pressure. All these parameters may have a significant impact on the spray characteristics and the local strand surface temperature. The presentation will also connect this information with considerations of strand surface quality, including defect sensitivity, microstructural parameters and internal oxidation phenomena.

Ji Joon Kim, POSCO, Korea, Republic of

Co-Author:
Young-Wook Jun, AIcraft Inc.
Jong-Chul Kim, POSCO

Abstract:
Reducing the slab width widening around the 400 series stainless steel is very necessary to improve the yield rate by reducing the amount of slab edge in the hot rolled coil. The amount of slab edge is multiple linear defects that occur within 20mm of both edges of the coil due to the widening of the slab narrow side during rough rolling of hot-rolling. In this study, a factory applied on-line model for the development of an artificial intelligence (AI)-based slab width prediction model is proposed. The proposed model collects operation data in units of 1 second during continuous casting and includes everything from the data preprocessing process to the learning and evaluation of the artificial intelligence model. A multilayer perceptron (MLP) model was used. The most important thing in the data pre-processing process is to align the working data by the position of the width of the slab. The developed width control model shows more than 95% of slab width prediction accuracy for both the learning data and the evaluation data. It is expected that the research model proposed in this study can be applied to the development of various predictive models with time series characteristics.

Riccardo Bono, Università degli Studi di Milano, Italy

Co-Author:
Marco Alloni, Prosimet S.p.A.
Riccardo Carli, Prosimet S.p.A.
Monica Dapiaggi, Università degli studi di Milano
Camilla Giada Baroni, Università degli studi di Milano
Andrea Bernasconi, Università degli Studi di Torino

Abstract:
The change in structure in casting powders as a function of their basicity is well known to have important effects on their rheology, and therefore on their success in casting. Different compositions of casting powders were prepared in the form of glasses, by melting the appropriate mixture and fast quenching. The structure of the glasses was studied by means of neutron total scattering at the spallation neutron source ISIS (UK), at the beamline NIMROD [1]. Even though amorphous materials do not possess a long range order, they do have a short range order, whose variations may be responsible for the change in properties. The total scattering data were corrected for all the scattering not produced by the sample and Fourier transformed into a Pair Distribution Function, which provides peaks in correspondence of interatomic bonds. The figure shows an example for 4 of the samples, with a different fluorine content: sample 10 has the highest fluorine content, while sample 11 has the lowest. The shoulder in the plot, at about 2.3 Å, corresponds to the Ca-F bond length. The data were analysed through the software EPSR (Empirical Potential Structure Refinement) [2], which allows the creation of a 3D model of the system under study. From the model, various geometrical and structural information can be gained, such as the distribution of coordination numbers, bond lengths and bond angles. This allows to fully understand the subtle differences in the local structure of the glasses, and therefore to produce casting powders with a better performance. References [1] https://www.isis.stfc.ac.uk/Pages/nimrod.aspx [2] Soper AK (2010) EPSRshell: a users guide. ISIS DisorderedMaterial Group, Didcot

Yongseok Cho, POSCO, Korea, Republic of

Co-Author:
Younhee Kang, POSCO

Abstract:
The ZRM (Sendzmir Mill) is the cold rolling mill which consists of 20 rolls to produce the stainless steels and the electrical steels. The work roll of the ZRM is so small to reduce the thickness of the strip efficiently. At the beginning of the rolling, the roll force set-up was performed for the desired thickness of the strip. If the set value of the roll force is not correct for the outlet thickness, the thickness deviation is high, furthermore the strip is broken during rolling. For the ZRM process, sound prediction of the roll force is vital for achieving the desired thickness because the stability of the rolling substantially affected by it. In this paper, mathematical model is presented for the prediction of the roll force at the beginning of the rolling. The model consists of a numerical model for the prediction of the roll force, a sub-model for the prediction of the mechanical property of the strip by the deep learning, which is the deep neural networks. It is called numerical model based deep learning. From the combination of these models, the roll force at the beginning of the rolling can be predicted to produce the desired thickness of the strip. The numerical model based deep learning has several advantages compared with typical deep learning. The prediction accuracy has been improved from the physical tendency of the numerical model. In addition, from reduced number of inputs of the deep learning model, the learning time was decreased. The prediction accuracy of the proposed model is examined through comparison with actual data.

Michael Breuer, SMS group, Germany

Co-Author:
Falk Töpfer, SMS group

Abstract:
When speaking of cold strip rolling, especially carbon strips, normally final gauges between 1.5 mm and 0.40 mm are referred to. Cold rolling of thinner strips keeps special challenges for the plant technology and the process control. In addition to the targeted final thicknesses, it is also important to attain the strip quality and the required product properties, such as flatness or surface quality. Rolling jobs which involve special challenges are preferred performed in reversing mills because here the rolling process is more manageable and a strip break has less impact on the production. The limitation on reversing cold mills, however, is the limited production capacity which, in the case of single-stand mills, is around 300,000 tons per year and in the case of two-stand Compact Cold Mills, around 600,000 tons, depending on the processed strip widths and strip gauges. A tandem mills productivity is even higher at a better yield rate together with a more simple process steps. There are regions on the world market - and this includes the Asia/Pacific region - which have a very high demand for cold-rolled thin strip in a thickness range of 0.50 mm to 0.15 mm. Two of the main applications for this material are roofing and packaging. With the capacities installed in this region alone, the demand cannot be met completely. SMS group supplied two coupled pickling and tandem roll mills especially for this demand. This paper provides an overview on the challenges and experiences we made during commissioning of this two PLTCMs. Focus is on mechanical equipment and process control items.

Jean-Pierre Robinet, CLECIM SAS, France

Co-Author:
Stanislas Mauuary, CLECIM SAS

Abstract:
Megatrends such as Electromobility shape the industrial world, this is today a well-known direction for steel producers’ development. For decades since the 80ies, Clecim has been present in Rolling and Processing of high silicon steels, always reinventing its products to fit with the new requirements. From industrial transformers to electromobility, the tolerances of silicon steel have gone more drastic in shape, flatness, thermal treatments and rolling precision. Of course, Clecim SAS remains true to its origins of rolling mill builder with the evolution of its Power 6-Hi mill for those products: smaller rolls, powerful coilers and torque, adaptive cooling solutions and of course, the necessary work roll and intermediate roll actuation with bending and shifting allow our mills to cope with flatness and quality in thin high strength gauges - always wider. The experience at the root of the edge drop management lies in process knowledge already acquired between 2004 and 2010 and enable Clecim to propose revamps of customers 4 Hi mills adapting the necessary actuators to limit edge losses. On Processing Lines, the advanced side trimmer and scrap choppers, able of online width adjustment complete the care for smooth edges and Asolid-state welding machines able to cut and weld laser wise have been the trademark and specialty of Clecim for more than one decade. Now, the new LW21L is designed for silicon very thin gauges and can match the sharp edge of the tolerances demands for final products dedicated to car motors, especially on stack of stator & rotor. The SIAS® DeepLearning including its pinhole channel offers the full set of analysis tools to detect the smallest defect. Today, Clecim SAS is proud to present you the evolution of its machines for electromobility business in details and the results achieved.

Sebastian Richard, SMS group, Germany

Co-Author:
Matthias Krüger, SMS group
Karsten Rues, SMS group
Christoph Helle, SMS group

Abstract:
In cold rolling mills vibrations of mechanical parts and/or strip can interfere several quality parameters like thickness, shape or surface quality. Since vibrations tend to occur at higher speeds, the rolling speed of single- or multi-stand mills for steel and aluminum has to be limited quite often. Among other mechanisms at cold rolling mills the so-called 3rd Octave and 5th Octave Chatter are the most important vibration issues. They are introduced by explaining related mechanisms and showing results of operational measurements. Subsequently some well-known measures against chatter issues and their consequences are listed and explained, like online Chatter monitoring with Auto-Slow-Down (ASD-) functionality. After giving a general survey about vibration issues in cold rolling mills and related conventional counter measures, the paper focusses on the development of SMS group to counteract 3rd Octave Chatter. The so-called X-Pact® Active Chatter Damping (ACD) uses Piezo electric elements as actuators which are located in an actuator box placed underneath the bottom backup roll chocks of a mill stand. A first pilot unit was put into operation in 2017 in a four-stand aluminium tandem cold rolling mill from SMS group. The optimization of the system and its integrated force measurement, including related tests and improvements to the mechanical design, was completed by April 2018. Permanent operation of the system is ongoing until today. The paper provides an overview of various operating results of the system during its normal operation. These are showing the reduction of vibration amplitudes and the increase of rolling speed with an active system. Beside of this, also the behavior of the system in the context of different vibration and excitation mechanisms is shown by practical examples. The parallel product development, with focus on product series implementation and improvements regarding performance and durability, is already applied in the actually sold applications.

Mehmet Burak Atan, İskenderun Iron and Steel Co., Turkey

Co-Author:
Gökhan Güngör, İskenderun Iron and Steel Co.
Arif Aksoy, İskenderun Iron and Steel Co.
Koray Aray, İskenderun Iron and Steel Co.
Onur Marti, İskenderun Iron and Steel Co.
Serdar Günbay, İskenderun Iron and Steel Co.
Erkin Yekda Gedik, İskenderun Iron and Steel Co.

Abstract:
In the iron and steel industry, water is one of the most significant inputs for production. The most common uses of water in the iron and steel industry are product surface cleaning, cooling, protecting equipment and improving working conditions for employees. The water which uses for surface cleaning contacts with the final products. Therefore, water quality has tremendous importance at this point. The quality of the water that comes into contact with the product can cause undesirable impacts in the quality of the material from time to time. Variables such as the chemical structure of the water, the residence time on the material, and the chemical type used in the treatment of the water affect the product quality. During the coil production in the hot rolling mill, it was determined that white spots on the coil and in detail examination, the element S broke the layer in the scale and and a white spot formation was detected with Cl reacted with AgNO3. After the occurrence of this situation, the limit values of the circulation water in contact with the product, the water source to be used and the chemical treatment of the circulation water were overhauled, and the problem’s repetition was prevented. Key Words: Water Quality, Coil Production

Łukasz Wójcik, Lublin University of Technology, Poland

Co-Author:
Grzegorz Winiarski, Lublin University of Technology
Tomasz Bulzak, Lublin University of Technology
Konrad Lis, Lublin University of Technology

Abstract:
The prediction of cracks in metal forming processes is a very important issue. It is very important from the point of view of designing the technologies in which these cracks may occur. One such manufacturing technology in which material cracking is very common is cross wedge rolling process. A rotary compression test was used to determine the limits of the fracture criterion. In order to determine the values needed to describe the fracture criterion, it was necessary to carry out laboratory tests and numerical simulations of the in-channel pressing process for discs made of EA1T steel under hot forming conditions. Experimental tests were carried out for forming processes at 950°C, 1050°C and 1150°C. The material tested was a disc shape with a diameter of 40 mm and a length of 20 mm; during pressing, the disc diameter was reduced to a diameter of 38 mm. The increase in forming temperature resulted in a significant increase in the forming path until fracture occurred. Numerical investigations were carried out in the finite element calculation environment Simufact.Forming 2021. Computer simulations were carried out for boundary conditions corresponding to laboratory rolling. Stress and strain distribution maps in the specimen axis were analysed during the study, which were then used to calculate the limit value of the hybrid fracture criterion dedicated to cross wedge rolling processes. After calculations according to the hybrid criterion and after statistical analysis, the limiting values of the fracture criterion were obtained, which are equal for a forming temperature of 950 °C - 0.7463; 1050 °C - 0.8936; 1150 °C - 3.1942.

Tomasz Bulzak, Lublin University of Technology, Poland

Co-Author:
Konrad Lis, Lublin University of Technology
Łukasz Wójcik, Lublin University of Technology
Grzegorz Winiarski, Lublin University of Technology

Abstract:
Cross wedge rolling is a technology used to produce preforms used in drop forging processes or axle and shaft forgings. The cross wedge rolling process is carried out using flat tools or rolls with wedges that, by cutting into the billet, progressively give it the shape of a forging. The technology has a lot of advantages, the most important of which are the high process efficiency and good accuracy of the forgings produced. A significant limitation of the use of cross wedge rolling technology, in particular for the production of responsible parts, is the adverse phenomenon of material cracking in the central part of the forgings during rolling. The advantages of cross wedge rolling can be exploited in the production of railway axles, which are currently produced by less efficient and less accurate technologies. Unfortunately, the phenomenon of material fracture introduces serious limitations to the implementation of this technology in industry. The paper presents the results of a study with the primary aim of eliminating material fracture. Numerical simulations using the finite element method were carried out prior to the experimental tests. Using cross wedge rolling technology and specially designed tools, a railway axle forging was rolled at various temperatures. The results of this study confirmed that the rolling temperature has a significant effect on the material fracture phenomenon in the cross wedge rolling process. By increasing the rolling temperature, the material cracking phenomenon can be eliminated.

Min-Seok Baek, Hyundai Steel Co. , Korea, Republic of

Co-Author:
Yong Soo Jeong, Hyundai Steel Co.
Seung Min Hur, Hyundai Steel Co.
Daeho Yun, Hyundai Steel Co.
Kwan Wook Kim, Hyundai Steel Co.

Abstract:
Recently, the steel applied to car bodies continuously requires high- and ultra-high strength steels. Accordingly, many researchers have conducted research on the development and strength improvement of dual & complex phase steel. As various studies progressed, the strength of steels increased, but a serious problem of edge cracks was formed, and many researchers made efforts to solve the problem. In the past, the cooling temperature was improved during the hot rolling process to reduce the martensite fraction, which directly affects edge crack formation. In addition, our company has conducted tests on various cooling temperatures and pattern changes to effectively roll steel plates. However, a unique phenomenon was observed in which edge cracking occurred at higher cooling temperatures. Therefore, in this study, the effect of ROT condition on edge crack formation was investigated, and the edge crack formation mechanism was discussed in connection with the microstructure analysis.

Gerhard Richter, ONEMET Technology Trading GmbH, Austria

Co-Author:
Xavier Rafael, Groupe IMCG SAS
Thierry Marlot, Groupe IMCG SAS

Abstract:
To reliably prevent material defects occuring in the course of downstream production processes such as e. g. hot rolling, cold rolling, etc. as well as in the final product, a corresponding treatment of the surfaces of the starting products like continuously cast slabs, blooms or billets is essential. While in the past cracks and other surface defects were mostly removed by means of scarfing, high-pressure grinding has now established itself as the superior technology for this purpose. Thanks to a controlled, even material removal (only as much as necessary, also on curved products) without any thermal impact on the material structure, no material losses due to the possibility of collecting the chips resulting from grinding by alloy and to recycle them, the environmental friendliness of the process (fossil-free, no CO2 emissions, clean exhaust air by filtering-out residual dusts which can also be recycled, etc.), as well as the excellent quality of the ground surfaces and high throughput capacity that can be achieved, high-pressure grinding is superior compared to scarfing but also milling. In order to ensure optimum operating results reliably and cost-effectively, a state-of-the-art grinding equipment tailored to the specific application and a profound user know-how for the grinding operation are necessary. Both can be guaranteed by Groupe IMCG as a specialized manufacturer and supplier of top-quality grinding machines (which also allow the utilization of the data and coordinates of surface defects detected beforehand by inspection systems for an automated flaw grinding) and experienced provider of conditioning services to the steel and special metal industries. As described in this paper, Groupe IMCG has also developed a powerful material data management system that allows all important material and process data to be acquired in real time and subsequently evaluated for process optimization and reporting purposes.

Özgün Yakar, Resonance Institute, Turkey

Co-Author:
murat ışık, isdemir

Abstract:
Hot rolling mill is a key section of a steel plant. The section produces vast amounts of steel sheet with different sizes and grades which are used extensively on automotive, pipe, construction and white goods industry. With respect to these high production rates, machinery reliability is on top importance for the plant. Rolling mills which need to work continuously without a flaw, consist of machinery that must be reliable in long term. Hot rolling mills usually have one or two rougher mills with an attached edger and 6 or 7 stand finishing mill. Each of these divisions contain nearly the same machine elements which are mostly a main drive motor, a gearbox to reduce speed and increase the load and a pinion stand to get a double output which are turning different direction to be able to drive the rolling stands. Each of these machines have very critical parts like roller bearings and reducers that have to be perfectly and continuously monitored in order to prevent developing failures. The article contains the detailed structure of the online condition monitoring system which is implemented on the hot rolling mill plant in Isdemir – Iskenderun/TURKEY. In the last section of the article a bearing failure which was detected with the help of the online system has been shared. Key Words: hot rolling, condition monitoring, vibration analysis, bearing fault, advanced diagnostic analysis, process parameters

Matteo Tomba, PERT Srl, Italy

Co-Author:
Nicola Tomba, PERT Srl

Abstract:
The reduction of energy consumption and the use of low-impact facilities, are now issues that every steel producer faces, since plants that pollute generate high costs and a high degree of mistrust on behalf of civil society, that perceives these works as a threat to its health.This article takes into account the electricity consumption resulting from the use of different types of rolling stands currently on the market, as well as the environmental impact due to their operation and considering the different technical characteristics of each type of stand. As well as introducing several advantages at a technical and economic level (reduction of CAPEX and OPEX) the new revolutionary PERT BS stands also lead to considerable savings in electricity, drastically reducing consumption. In the first analysis, we take into account the greater difference between BS and housingless — i.e. the absence of spindles with regards to the BS. From the point of view of energy saving, it is clear that the elimination of spindles involves a considerable simplification of the kinematic chain that allows the transmission of motion from the electric motor to the rolls.

Christian Overhagen, University of Duisburg-Essen, Germany

Co-Author:
Linfeng Zhu, University of Duisburg-Essen
Wanyun Mao, University of Duisburg-Essen
Maolin Liu, University of Duisburg-Essen
Sichen Zhou, University of Duisburg-Essen
Kaiqi Fu, University of Duisburg-Essen

Abstract:
Classical approaches of roll pass design (RPD) for finished full sections require a two-step method. First, main grooves are designed according to a predefined elongation distribution to meet the requirements of the intended process in terms of temperature evolution, power demand and section tolerances. In the second step, the intermediate grooves are designed in order to fulfill prescribed filling ratios, taking into account the specific spread behaviour of the rolling process. This process is a trial-and-error method and often requires a high number of iterations to yield a satisfying solution for all passes. Extra complexity exists for diamond-diamond pass sequences in which a final square section is produced in few passes without predefined main grooves with similarities to the three-roll process, suffering from the same restrictions. To speed up the design process and to initiate a framework for a fully-automated solution, the RPD problem is solved by a machine-learning method in the present study. Using the industrially approved RPD software MPC developed at our research group, we generated training data for the pass sequences round-oval-round, square-diamond-square and diamond-diamond-square in the two-roll process, as well as round-round and round-hexagon in the three-roll process, each for a range of roll diameters and total reductions. The fully-connected neural network trained with these data is able to predict pass designs within the trained data ranges. Verification data was generated which does not coincide with the training data to test the network against overfitting. Model results are presented and cross-validated against the analytical RPD model. The resulting ML pass design model is implemented in Python using the PyTorch library. Source code for including the parameters of the neural network will be published for third-party evaluation.

Amit Ahsan, SECOPTA analytics gmbh, Germany

Co-Author:
Christian Bohling, SECOPTA analytics GmbH

Abstract:
Due to modern days automation processes inside rolling mills, the risk of material mix-ups is pretty low. However, given the rising demand for smaller production lots and the constantly growing number of steel grades, reliable material identification along the entire process chain is still one of the highest concerns. The current state-of-the technologies (e.g., spark, magnetic induction testing) fall short to guarantee a 100% reliable check at the end of the rolling process (e.g., before shipment). On the other hand, at the beginning of the rolling process, manual activities such as picking input or semi-finished material from the storage to charge into reheating furnace often leads to material mix-ups as well. Particularly, when safety-critical components are concerned, a mix-up can have catastrophic consequences (e.g. shipment cancellation, penalty charges, loss in reputation). With fully integrated precleaning (e.g. scale, decarbonization layers), SECOPTA developed LIBS (laser-induced breakdown spectroscopy) based sensor can analyze every moving bar (bright or black) more precisely (with respect to heat/ melt shop value) at the speed of 2 m/sec. Additionally, it can check each billet or ingot before the charging of reheating furnace assuring maximum safety without any human interference. Depending on the risk of mix-up, fiberLIBS can be integrated into the existing process (e.g., finishing line, NDT line, before reheating furnace) and fully compatible with Manufacturing Execution System Systems (MES), ensuring industry 4.0, 100% mix-up testing with significantly low maintenance and operating costs. Since 2019, SECOPTA has carried out multiple successful installations in highly reputable special steel manufacturer facilities and years of 24/7 process operation have proven that fiberLIBS can detect out-of-spec material with more than 99,9 percent reliability. The paper followed by the Estad presentation will introduce this inline LIBS-based Positive Material Identification (PMI) technology and discuss its reliability with real-life process data.

Mark Kreso, EMG Automation GmbH, Germany

Co-Author:
Timo Gemmer, EMG Automation GmbH
Jens Bublitz, EMG Automation GmbH

Abstract:
Electrical sheets - along with magnets and lacquered copper wires - are key components for the manufacturing of electric drives. The projected growth of e-mobility will increase the demand for electrical sheets for the automotive industry from 100 thousand tonnes in 2018 to about 1.2 million tonnes in 2030. Quality assurance and the control of quality costs for electrical sheets thus determine the profitability of motor manufacturers to a large extent. The thickness and homogeneity of the insulating coating play a special role here. Beta transmission, used until now to determine mass per unit area, thickness, and density, will soon reach the limit of its availability. Different isotopes (krypton, strontium, promethium) are used for different weight ranges, but Promethium can only be purchased for the next 1 - 2 years. The EMG SOLID® systems, so far used for the quantitative determination of lubricant layers on sheet metal, offer an ideal replacement. Especially laser-induced fluorescence (LIF) can be used to reliably determine the desired measuring data online. The system parameters, e.g., laser excitation and observation wavelength of the fluorescence, detector sensitivity or signal timing are specifically adjusted to guarantee an optimal system adaptation to the respective type of coating. An additional reference measurement on uncoated sheet surfaces, e.g., by a suitable backscatter method, represents a further possibility for optimising this application. Coating thicknesses between 0 - 7 µm (incl. dark pigmented coatings) could be successfully determined. The methods are designed for inline or online measurement operation, also in traversing mode with typical travel speeds of up to 1 m/s. The EMG results clearly show that quantitative detection of insulating varnishes on electrical sheet in the micrometre layer thickness range is reliable possible. This paper describes the technological background of the method and shows laboratory as well as first application results.

Jorge Martinez, Tenova HYL, Mexico

Co-Author:
Jorge Martinez, Tenova HYL

Abstract:
Among the various approaches for decarbonization of the steelmaking industry, Direct Reduction has proven to be the right solution, thanks to the readiness of the technology, effectiveness in abatement of the GHG emissions and cost effectiveness. When using DRI, two main routes should be considered, based on the intensive use of hydrogen (H2) (CDA) and capture and use of CO2 (CCU). One consists of the progressive conversion of the BF-BOF facilities to direct reduction-electric arc furnace (DRI-EAF). The second alternative is the production of hot metal (HM) by installing a gas-based direct reduction plant feeding DRI to an open slag bath furnace (DRI-OSBF). ENERGIRON®, the DRI technology by Tenova and Danieli, is the benchmark for sustainability and provides the needed flexibility during the current historic period of energy transition. Schemes for liquid steel production with reduced or practically nil carbon input by using H2, its equivalent cost for DRI production and the reduction of CO2 emissions are analyzed

Gerald Wimmer, Primetals Technologies Austria, Austria

Co-Author:
Bernhard Voraberger, Primetals Technologies Austria
Johannes Rosner, Primetals Technologies Austria

Abstract:
"Today the iron and steel industry is the largest global industrial CO2 emitter, its main emissions coming from iron making via the blast furnace. Direct reduction using low-carbon hydrogen is at the moment the most promising solution to achieve the industry target of climate neutrality. However, the common solution to use EAF for processing of DRI is only beneficial for high grade ores, while most of the iron ores globally available is of lower grade with higher gangue content. New solutions for profitable processing of such lower grade direct reduced iron are required. A two-step process combining a Smelter for green hot metal production with a BOF converter can handle such lower grade ores and might become a prefered solution for an implementation in existing integrated plants. The Smelter is designed to handle wide range of direct reduced materials coming from MIDREX, HyREX or HYFOR plants. The Smelter allows for efficient separation of slag and metal; after granulation the slag from the Smelter can be used in the cement industry as an latent hydraulic active binder similar to blast furnace slag today, promoting the circularity of ironmaking. The Smelter is designed for continuous operation with a large hot heel and charging and tapping during power on. Annual productivity up to 1,5mta can be achieved with one Smelter, for higher productivity two Smelters will be operated in parallel. In the paper the principles of the two-step process as well as the main design features of the Smelter will be presented together with an outlook on the implementation and upscaling plan."

Hagen Fuchs, Primetals Technologies Germany, Germany

Co-Author:
Ali Hegazy, Primetals Technologies GmbH
Michel Hein, Primetals Technologies Germany
Hans-Jörg Krassnig, Primetals Technologies Germany

Abstract:
Fueled by net-zero prompts and to comply with the most stringent environmental targets, the world is about to witness a fast-paced transition into green steelmaking. DRI-based EAF route will play a crucial role in this green steel transition due to its significantly lower carbon footprint compared to the integrated route, while still ensuring the highest product quality. This paper will illustrate the position of DRI and EAFs within the green steel market regarding raw material quality, feedstock market, and CO2 emissions. The paper will also discuss the process design for DRI-based EAFs and provide an inside on the combination with multiple direct reduction technologies such as MIDREX, HyREX, and HYFOR. Features of the latest state of the art 220-t DRI-EAF by Primetals Technologies for Salzgitter Flat Steel in the heart of Europe will be highlighted (start-up in Y2025). Latest operational results will be reviewed, including project execution, productivity, consumption figures, slag control, product quality, and maintenance for cold and hot DRI-based EAFs from Primetals Technologies.

Ian Cameron, Hatch Ltd., Canada

Co-Author:
Mitren Sukhram, Hatch Ltd.
Nicholas Aubry, Hatch Ltd.
Takshi Sachdeva, Hatch Ltd.
Pauli Baumann, Hatch Ltd.
Sa Ge, Hatch Ltd.
Terrance Koehler, Hatch Ltd.
Richard Elliott, Hatch Ltd.

Abstract:
Many steel producers are focused on replacing their blast furnaces with direct reduced ironmaking (DRI) as a greenhouse gas (GHG) reduction strategy. While several producers have announced plans to smelt DRI with a standard electric arc furnace (EAF), others are considering electric smelting furnace (ESF) technology to produce hot metal suitable for basic oxygen furnace (BOF) steelmaking. Drivers for the adaption of the DRI-ESF-BOF route include the ability to use traditional higher gangue iron ore, slag valorization for cement manufacturing, better impurity control such as nitrogen and phosphorous in the liquid steel and to avoid stranding existing BOF steelmaking assets. Most producers have selected the DRI route for its potential to start with the well-understood natural gas-based technologies and then transition to greater amounts of green hydrogen as this becomes available. Carbon in hot metal will be essential for the ESF and BOF stages of the new process route even as natural gas is replaced with hydrogen. How best to carburize the ESF hot metal when iron ore is reduced to metallic iron using hydrogen is an open opportunity for technical innovation. Little attention has been paid to the re-use of the CO and CO2 rich gases generated from the ESF and BOF to carburize the DRI prior to smelting. The authors will present technical approaches to re-use these off-gases in-plant to minimize the GHG emissions from the DRI-ESF-BOF value chain, especially in the context of a transition to green hydrogen-based iron ore reduction. Needed technologies such as effective gas separation, methanation, reverse water gas shift, and carbon cycling will be discussed, and a new integrated flow sheet will be proposed.

Peter Kinzel, Paul Wurth S.A., Germany

Co-Author:
Fernand Didelon, Paul Wurth S.A.
Miriam Valerius, Paul Wurth S.A.
Jihong Ji, Paul Wurth S.A.

Abstract:
In view of the new economic reality, Paul Wurth has reassessed the existing integrated steel plant assets in the light of the European CO2 emission ambitions. Natural gas not being available in the short term and seeing the scarce scrap and high grade pellet availability after 2030, it will be of the essence for cost efficient European steel plants to count on a CO2 lean process for massive steel production based on the well established reduction melting process. Paul Wurth has in this respect come up with a concept allowing the easy substitution of the traditional blast furnace by a compact direct reduction and melting furnace. This new furnace, EASyMelt™ can be the key in existing steel plant set ups allowing highly cost efficient steel production as well as satisfying the net zero carbon target

Alexander Thekale, Primetals Technologies Germany, Germany

Co-Author:
Christian Horn, Primetals Technologies Germany
Martin Kerschensteiner, Primetals Technologies Germany
Dominik Wassermann, Primetals Technologies Germany
Andreas Bauer, Primetals Technologies Germany

Abstract:
In steel manufacturing a core task of operators today is plant supervision. Cameras are a cost-effective way of displaying crucial parts of the plant to give operators an overview of ongoing production processes. However, the sheer overload of information by dozens of simultaneous video streams can be a challenge for workers and could lead to delayed interventions upon problems. Machine learning as a part of artificial intelligence has proven to be an effective solution for addressing this problem. By applying computer vision models and techniques, machines can gain a high-level understanding from input images and videos. Enriched with domain specific knowledge and additional plant information, it becomes a digital assistant or digital expert. It enables detecting and notifying operators on critical conditions of involved processes and components to increase quality and reduce downtime; digital experts can even actively interact with the process. In order to be able to use machine learning based digital assistants in an industrial environment, a robust framework must be created that is suitable for continuous operation. With this paper we present an approach on how digital assistants can be deployed for industrial applications. We describe the various challenges and outline an intuitive process to build a production-ready solution which is integrated into the existing plant software infrastructure. In addition, we illustrate how several aspects like monitoring and versioning can be realized. Using a real-world example of a digital assistant, we demonstrate the successful realization of our solution.

Roman Markus Holler, PSI Metals Austria GmbH, Germany

Co-Author:
Joachim Gnauk, PSI Metals GmbH
Hannes Sperl, PSI Metals GmbH

Abstract:
Blockchain technology is a potential game changer for the entire chain of the manufacturing industry. Over the past years, reliable tracking of goods using blockchain technology has become a major topic as it enhances transparency and traceability of products while revealing information like the history and origin of the products. While it is important to use blockchain technology to create a reliable and transparent traceability, such transparency partly reveals confidential information about production processes. This kind of scenario is not peculiar to special steel producers supplying sensitive industries, but also to conventional production chains where confidential information might be derived from the published information. In our paper, we will reveal how zero-knowledge proofs (ZK proofs) create increased transparent tracking while keeping confidential data. The standard EN 10373 describes certification of metallic products complying with EN 10204 using computational models based on sensor data captured during the production processes. By combining EN 10373 with blockchain technology and ZK proofs, producers can successfully compute the product’s quality without revealing anything about the production details. Keywords: Blockchain, Zero-Knowledge Proofs, Product Tracking, Transparency, Computational Models

Marcus Neuer, VDEh-Betriebsforschungsinstitut GmbH, Germany

Co-Author:
Andreas Wolff, VDEh-Betriebsforschungsinstitut GmbH

Abstract:
Modern process industries is driven by decision making, decisions which need solid factual understanding of a situation. Through the recent successes of artificial intelligence, mainly due to its subfield of machine learning, prediction and knowledge models are available to support those decisions. Explainable AI (XAI) developed techniques for fusing expert knowledge, existing physical equations and easily to interpret relations to provide more insight into the result generation of machine learning models. Counterfactual AI provides a way to work with the available data and to introduce straightforward means of mathematical logic and conditional probability into real. Such systems can answer hypothetical question like „if the tension at the rolling would not have been too high, would the strip would still have been damaged“. This requires the AI system to first adopt a perspective that is not present in the current data set evaluated, second, to utilise all previously learned information and third to combine it in form of Bayesian conditional probabilities to actually predict the scenario in which the questioned parameters would have occurred. Counterfactual AI is therefore able to scan its own machine learning input variables for „what-if“ scenarios, which can be straightforwardly applied to selected use cases in steel processing and process industry in general. In more global context, Counterfactual thinking in autonomous systems is one step towards Causal AI. The latter combines common machine learning approach on data, causal inferences on the found relationships including counterfactual questions and lastly physics-informed approaches with analytical process models. The talk will give details on the described techniques and presents real world applications of the discussed methods. It will cover different processes of the steel production route like continuous casting and rolling, to display the advantages brought by Causal and Counterfactual AI.

Niklas Reinisch, RWTH Aachen University, Germany

Co-Author:
Tarik Viehmann, RWTH Aachen University
David Bailly, RWTH Aachen University
Gerhard Lakemeyer, RWTH Aachen University
Gerhard Hirt, RWTH Aachen University

Abstract:
In recent years, many production processes, including open-die forging, have been digitalized, resulting in process data and process knowledge being available in many places. However, this knowledge is often decentralized, e.g., in individual companies, and cannot be consolidated in one database easily due to stakeholder interests (secrecy, ownership, etc.) or the volume of data. In order to nevertheless draw added value from all available process data, a multi-agent system (MAS) is presented using the example of an open-die forging. Based on an ontology, the individual agents can communicate semantically with each other to exchange information. A top-level service broker manages the available services and forms the link between agents and user interface. In this manuscript, a MAS-demonstrator is presented that provides two example services, the material choice of a forging as well as the design of an optimal pass schedule. For this, the MAS uses process data along the production chain of an open-die forging as well as an ontology designed to represent this production related data. In the MAS multiple agents are included, representing different stake holders along the production chain like the steel retailer, the steel producer and the open-die forge.

Luca Neri, SMS group, Italy

Co-Author:
Luca Neri, SMS group Spa
Andrea Lanari, SMS group Spa

Abstract:
Reduction of CO2 emission in steel production and transformation to green energy sources demand a highly efficient and flexible power supply for electric arc furnaces (EAF). Integrated BOF routes usually provide very weak grids, which do not allow the connection of demanding EAFs without major changes in the power network topology. The new family of IGBT based electrical modules is capable of feeding EAFs from 5 MVA up to 350 MVA. A fully modular technology concept provides the demanded efficiency and power density in order to serve the needs of the green steel transformation. Using this innovative modulation, technologies and proprietary control algorithms, which take full advantage of the power electronic capabilities, ensure highest power transfer and lowest impact on the grid’s power quality. A real project case is showing the challenges and needs of the implementation of EAFs for green steel production, and how the fully modular technology allows our journey into a CO2 reduced and green energy powered steel production.

Wolfgang Linden, SMS group, Germany

Co-Author:
Alexander Feldermann, SMS group
Volker Paersch, SMS group

Abstract:
The metals industry is on its way to replace the high CO2 emissions generated by the use of fossil fuels with renewable energies in order to achieve climate-neutral steel production. Rising prices for fossil fuels and the increase in CO2 taxes are further incentives for switching to a climate-friendly energy supply. The time is now for SMS group to make the most of its unique core competencies, technologies, and partnerships to provide all climate-neutral processes from a single source. With its pooled expertise in process and energy management, SMS group is able to connect all plant areas to a cost-efficient power supply network. This is achieved through a central connection to the public AC grid and available renewable energy sources, for instance solar or wind energy, as well as to energy storage units that include battery storage systems. The paper explains, how DC ECO GRID from SMS group connects these to hybrid power networks (AC and DC), thus improving the plants' energy efficiency. Thereby a holistic solution from SMS group combines energy management consulting services, a defined business case, the development of concepts and solutions, and the integration of systems – all from a single source. The DC ECO GRID helps to provide a greener, more energy-efficient power supply for steel plants, both new and existing. In this way, it creates a link between a more environmentally friendly metals industry and new green energy supply systems.

Todd Astoria, Midrex Technologies, Inc., United States

Co-Author:
Matt Hargreaves, TUTCO SureHeat

Abstract:
The iron and steelmaking industry is experiencing rapid market change and technology developments. One of the key drivers for the market change is the need to improve the environmental impact of the processing routes. The reduction of CO2 emissions is one of the most important environmental goals facing the industry. The Direct Reduction (DR) – Electric Arc Furnace (EAF) is one of the most promising technologies to achieve CO2 reductions. In order to achieve the reduction, the DR plants are extending their fuel options to include green hydrogen. Hydrogen has great promise for the direct avoidance of CO2 from the DR route when used as the process fuel; however, hydrogen has drawbacks when applied as a fuel for heating the Process Gas in the conventional combustion-based heating unit operation. Generally, green hydrogen is produced from electrolysis. If hydrogen is used as a fuel in a combustion system, then it can reduce the CO2 emission compared to a typical fossil-based fuel. However, inefficiencies are introduced when electricity is used to produce hydrogen, which must then be transported to the facility. In order to overcome the inefficiencies then it is advantageous to use electricity to directly heat the Process Gas. This paper focuses on the advancements that are being made in the field of electrical heating of process gases in the Direct Reduction facility.

Miriam Laubrock, Fachhochschule Münster, Germany

Abstract:
One essential criterion for the design of joints in many applications is the fatigue behaviour with a coincident focus on lightweight design. In this case an increase of load cycles by the use of high strength steels in combination with welding is limited. Experiences from sectors like automotive engineering show, that bonded joints exhibit excellent behaviour under cyclic loads. Nevertheless, there is only a low use of adhesive bonding in sectors like agricultural engineering, commercial vehicles or plant engineering. One important reason for that is mainly a lack of regulations and standards, as they already exist for the design of welded joints. Typical standards used are for example IIW-guidelines, the Eurocode or the FKM-guideline. They allow the determination of Woehler curves for welded joints, while a design method for adhesive joints is not included. In addition to that, the boundary conditions in these sectors are different to those seen in automotive engineering. They can be characterized by a lot of small and medium sized companies using a large proportion of manual manufacturing methods. Further differences arise from the wall thickness of the steel sheets used, tolerances and the corrosive conditions caused by the respective environment. In order to fill this gap, a design method for load-bearing adhesive joints in applications using thicker steel sheets was developed according to the FKM-guideline. The method is based on only few input variables to create a Woehler curve and to estimate the operational stability of an adhesive joint as it can be used in the sectors mentioned.

Maxime Monnoyer, Fives Keods, France

Co-Author:
Stéphane Mehrain, Fives Stein
David Barbier, Fives Keods

Abstract:
UHSS and 3rd generation AHSS remain the best cost-effective solution for lightweighting of Automotive body in white applications, providing excellent combination of strength and formability. These steel grades are developed and processed in order to obtain multiphase microstructures with a substantial amount of retained austenite in order to achieve best possible ductility and in-use properties. Their processing imposes some constraints compared to conventional steels among which increased alloying contents, increased soaking temperatures, higher cooling rates, coatability and operational flexibility limitations. Such metallurgical and operational challenges can now be overcome thanks to key, newly developed, technologies whose advantages and features will be further presented. Induction technologies (Transverse and Longitudinal flux) allow rapid heating over a large temperature range as requested for the management of multiphase materials, thus avoiding the implementation and management of long conventional heating sections. Moreover, they allow efficient strip re-heating in the case of complex annealing cycles such as for example Q&P concepts. Application of wet cooling technologies achieve several objectives: first, high cooling rates enable managing all the product dimensional ranges without changing the metallurgical recipe whatever the strip thickness. Also, they allow fast and continuous cooling rate between high temperature soaking down to low quenching temperature as required by 3rd generation AHSS metallurgical concepts. Moreover, newly developed wet quenching technologies allow UHSS strip coatability even with high amount of Mn and Si. Overall, it can be demonstrated that new processing technologies dedicated to 3rd generation AHSS allow leaner metallurgical concepts and present high potential for cost and quality improvements.

Hans-Günter Krull, Deutsche Edelstahlwerke Specialty Steel GmbH & Co. KG, Germany

Co-Author:
Jamila Adem, Ugitech SA
Frank van Soest, Deutsche Edelstahlwerke Specialty Steel GmbH & Co. KG
Clara Herrera, Deutsche Edelstahlwerke Specialty Steel GmbH & Co. KG

Abstract:
The number of steel grades used for high pressure componentsis in a hydrogen environment is very limited. The effect on Hydrogen on the mechanical properties of steels are shown. An overview of the RRA values (relative reduction of area) of stainless and engineering steel grades will be presented and recomandation for grades regading cost and mechanical properties are given.

Alexander Gramlich, RWTH Aachen University, Germany

Co-Author:
Hauke Springer, RWTH Aachen University
Ulrich Krupp, RWTH Aachen University

Abstract:
The steel industry is a major contributor to global carbon emissions, with the production process being energy-intensive and relying heavily on fossil fuels. It is therefore crucial to find ways to reduce the carbon footprint of the industry in order to mitigate its impact on the environment. One such method is through scrap recycling, where existing steel products are reused instead of producing new steel from raw materials, saving on energy and resources. However, pronounced material integration and multi-material use in technical products lead to a contamination of steel scrap. Some of these contaminations cannot be economically removed during remelting and refining in the electric arc furnace and therefore, a gradual accumulation of detrimental impurities, like Cu or Sn, causes a deterioration of quality. Accordingly, the respective recycling steel grades are not sufficient to fulfil the demanding specifications of flat products, e.g. in the packaging or automotive industry. Strong segregations at the prior austenite grain boundaries leads to the problem of hot shortness, i.e., massive embrittlement of hot-formed steel products. Therefore, a need for the investigation of the influence of elements like Cu on the properties and processability of different steel grades exists and new approaches for tolerating higher Cu concentrations must be developed. The study presents the effects of adding 0.5% and 1.0% copper to reference alloy 42CrMo4 on its transformation behavior and mechanical properties. To investigated the risk of Cu-embrittlement, hot tensile tests were performed. Microstructures are investigated with light optical, scanning electron, and transmission electron microscopy. The results show that copper contamination, which is unavoidable in steel recycling, has the potential to increase the hardness and strength of high strength steels, if it can be controlled during the processing.

Rabi Lahdo, Laser Zentrum Hannover e.V., Germany

Co-Author:
Stefan Kaierle, Laser Zentrum Hannover e.V.
Frank Riedel, Fraunhofer Institute for Machine Tools and Forming Technology
Markus Puschmann, Fraunhofer Institute for Machine Tools and Forming Technology
Patrick Urbanek, Fraunhofer Institute for Machine Tools and Forming Technology
Jörg Hermsdorf, Laser Zentrum Hannover e.V.
Sarah Nothdurft, Laser Zentrum Hannover e.V.

Abstract:
Duplex stainless steels are utilized for many applications in oil, gas and hydrogen industry due to their excellent properties regarding strength, toughness and corrosion resistance. This outstanding performance is realized owing to a two-phase micro-structure of ferrite and austenite with a portion of at least of 30 % austenite. During welding, this microstructure ratio can be lost because of unfavorable heat input. Arc welding processes have become established in practice for welding duplex steels. These welding processes can produce joints with the required microstructure ratio, but the productivity is low. Beam welding processes exhibit high productivity, however cannot produce welded joints with the required microstructure ratio. Laser beam-submerged arc hybrid welding combines the advantages of both welding processes and can be a good alternative with high productivity. In this study, laser beam-submerged arc hybrid welding processes are developed for butt joints of duplex stainless steel S31803 with different thicknesses of 16 mm, 20 mm and 30 mm using a disc laser beam source with a max. output power of PL = 16 kW. In this context, the parameters laser beam power, welding speed, wobble amplitude and the edge preparation are investigated to achieve a good weld appearance, 30 % austenite content and an impact energy of at least of 40 J at a test temperature of −40 °C. By means of visual inspections, metallographic analysis and Charpy impact tests, it can be proven that the weld seams meet these requirements. As results, efficient high-performance welding processes with welding speeds of up to vS = 1.0 m/min are achievable. Based on these results, laser beam-submerged arc hybrid welding has been shown to be a welding method with high productivity, which can play an important role in the future for the welding production of duplex steel parts.

Gabriel Korkmaz, Paul Wurth S.A., Luxembourg

Co-Author:
Mathias Hoffmann, Paul Wurth S.A.
Wolfgang Kern, Paul Wurth Italia S.p.A.

Abstract:
Decarbonization route for most steelmakers is already described for the next decades. However, the remaining operation time of the existing coke oven plants will be a challenging task for the coke producers. The more and more stringent requirements of local and national authorities force the coke producers to continuously update the operation and equipment. In light of this situation various technologies have been developed to support the coke producers in order to meet the environmental requirements. Environment and safety aspects are to be respected and therefore it is necessary to keep attention on typical areas of coke oven plants to ensure a continuous and safe plant operation. Several new technologies have been developed over the last years and proven to be very effective in order to fulfil the requirements with regards to environmental protection. This paper will highlight the areas of concern in the different sections of a coke oven plant: from the coke oven battery, moving machines and by-product plant. Moreover, it will demonstrate effective solutions as upgrades or adjustments implemented in various coke oven plants all over the world to ensure the environmental protection performance. These technologies can be applied for new coke oven plants and for modernization of existing coke oven plants.

Sebastian Riethof, thyssenkrupp Steel Europe AG, Germany

Abstract:
The Climate change, which is becoming increasingly evident, has an impact on our plants worldwide. Temperature-sensitive processes in particular are significantly impaired by the longer periods of hot weather. Higher cooling capacity is becoming unavoidable for constant production. The raw coke oven gas (COG), generated at Coke Plant Schwelgern, is treated in the by-product plant and its valuable by-products are recovered by multi-stage absorbers. These processes are temperature-sensitive. The governmental permit limits the environment relevant concentration of substances like hydrogen sulphur in the purified COG and controls the limits via online monitoring. The efficiency of COG-treatment is sufficient, if the process is operated following the design parameters. The efficiency decreases during hot summer times which becomes more and more relevant. The original design of Coke Plant Schwelgern was not able to guarantee full production at hot summer times without violation of the environmental COG-limits. The necessary cooling capacity for the absorption processes at the Schwelgern coke plant is provided by cooling towers. Thus, the cooling capacity depends on the ambient conditions, the installation of additional chiller cooling capacity becomes necessary. Conventional chillers have a very high electrical energy requirement and, in addition, the coolant is harmful to the environment, alternative energy sources must be tapped. At Coke Plant Schwelgern, the by-product plant generates a steady flow of hot waste water, which is an untapped potential for chiller water generation. The so-called absorption chillers can use this heat source to generate cooling water for cooling down COG and circulating water feeds to optimize the COG-treatment during hot periods, guaranteeing full coke production without violation of environmental COG-limits. This presentation illustrates the theoretical considerations for this project, reflects about commissioning and presents first results.

Wolfgang Kern, Paul Wurth Italia S.p.A., Italy

Co-Author:
Alessio Ferraris, Paul Wurth Italia S.p.A.
Fabio Cerutti, Paul Wurth Italia S.p.A.
Gabriel Korkmaz, Paul Wurth S.A.

Abstract:
For many countries, steel production will rely for the foreseeable future, on the blast furnace route. There will be optimization processes taking place at the blast furnace, from PCI injection, coke rate reduction to Syngas injection to limit the carbon footprint. Nevertheless, availability of good quality coke at a reasonable price level will be required to ensure a stable operation of the Blast furnace in some regions for years to come. To produce good quality coke it is required to utilize high quality coking coals with excellent coking behavior to ensure a continuous and stable carbonization process through traditional top charged coke oven batteries. Due to the limited availability of good coking coals on the world market and the ever increasing cost for these coals, a trend can be seen with more and more coke producers changing from top charged coke oven battery operation to stamp charged coke oven battery operation in several parts of the world. When applying the stamp charging coke making process the selected coal blend will be compacted before charging into the coke oven. Such compacting will allow the coke producers to apply coals with less favorable carbonization behavior and still enable them to produce the desired high quality coke for the blast furnace operation at a lower cost. The stamp charging technology is particularly interesting in countries with large coal reserves, however the coals having lower or limited coking and carbonization characteristics. Through the introduction of the stamp charging process, these countries will be less dependent on the import of expensive coking coals. The paper will provide an overview on the coke making trends in several regions of the world.

Thomas Taylor, thyssenkrupp Steel Europe AG, Germany

Abstract:
This presentation contains the key data of coking plant Schwelgern including coke demand of Thyssenkrupp steel Europe at different stages. Short overview of the different D.R.I.-processes, chosen location in the “past” and “future”. Gas supply D.R.I taking both increasing gas prices and decreasing availability in Europe into account. The presentation will also give a closer look to the coking plant Schwelgern as bridging technology providing coke oven gas to D.R.I-processes and the effect on Thyssenkrupp Steel Europe as the result of reduced COG supply to other processes in the steel plant.

Peter Liszio, thyssenkrupp Steel Europe AG, Germany

Abstract:
Coking plant Schwelgern set the state of the art of cokemaking after commissioning in March 2003. This presentation is reflecting over the last 20 years and gives a resume about its pro and cons of design, production, environmental and management developments, raw material optimization and a future outlook.

Joaquín B. Ordieres Meré, Universidad Politécnica de Madrid, Spain

Co-Author:
Andreas Wolff, VDEh-Betriebsforschungsinstitut GmbH
Antonio Bello-García, Universidad de Oviedo
Stefano Dettori, Scuola superiore di studi universitari e di perfezionamento Sant'Anna

Abstract:
Productivity in modern metals plants and processes depends on sophisticated computer-controlled automation systems that have become powerful, and ubiquitous. It is part of the Internet of Things (IoT). In the case of automation, the computers that make production smarter also make it more vulnerable to external interference. Manufacturers have become more vulnerable to cyber-attacks after shifting to Cloud infrastructure and services, since from 2017, there have been approximately 382 new vulnerabilities, and additionally, the crackers have had the tendency of exploring targeting vulnerabilities before the security research team and responsible software vendors realize their presence. After reviewing several RFCS research projects in the context of the RFCS EU funded dissemination project named ControlInSteel, it becomes clear that many of the created models for forecasting can be useful for estimating bias between expectations and measured values. Unlike earlier analytical attempts to find more effective model representations, the cloud oriented Operational Technologies provide scalable solutions enabling different applications. Such applications not only are useful for low level monitoring activities, but also to create higher level of representation of data, mainly product oriented with high traceability on the low-level data. This paper wants to present the different capabilities that cloud OT solutions enable, both in process monitoring, OT oriented cybersecurity, and high-level data representation. All the analysis will be carried out by using a case study from the hot strip mill for long products in the context of the EU funded Autosurveillance project.

Sheetal Birla, Falkonry, United States

Abstract:
Steel manufacturing processes are heavily instrumented, generating large volumes of automation data in the form of time series to the tune of over 5 million data points per second per plant. The time series data contain adequate information to represent the state of a physical system and production process at any given point in time. However, prevalent data-driven fault detection methods require significant setup efforts and expert inputs for modeling every known state of the system. This paper presents a novel self-supervised AI approach that does not require any setup effort and is capable of monitoring every existing process parameter and asset metric at high speed. Our approach utilizes a deep learning architecture based on Convolutional Variational Autoencoders (CVAE) that can start learning from small amounts of data to identify excursions, can automatically and incrementally learn as the underlying behavior of the asset changes and can process millions of measurements a second across thousands of time series. The automated time series AI informs plant operations of conditions that require human attention and provides diagnostics of underlying issues - leading to informed production and maintenance decision-making. Self-supervised AI overcomes the challenge the conventional machine learning method faces scaling to the needs of steel manufacturing by accommodating the challenges of constant equipment, environment, and product changes that hinder classical supervised learning methods. This paper will show this new AI in commercial steel manufacturing operations today.

Tarun Mathur, ABB AB, India

Abstract:
Artificial Intelligence (AI) is a key enabler for amplifying return on investment for digital technologies. There are many examples of big data, cloud platforms and data integration investments in the steel industry though much fewer for intelligent applications that convert this data into value. The complex nature of operations in a steel plant along with unavailability of large historical data pose a significant challenge to deploying artificial intelligence projects. This paper details several applications of AI in steel manufacturing for operational excellence, process performance and reliability improvement. The first application concerns improvement of manual and complex operation of the steelmaking shop using data from all meltshop processes, ladles, cranes etc. to build a machine learning model that predicts temperature losses for heats. It then prescribes the lifting temperature to the ladle furnace operator resulting in better superheat compliance, thus improving average caster speed and reducing energy input at ladle furnace. The second application uses data-based models to predict and control process performance by utilizing the well-known Model Predictive Control framework. This kind of application works in a closed loop with the automation system, correcting PID setpoints towards a more profitable operating range. These applications work well for slower and continuous processes such as those in pellet or sinter plant, grinding, reheat furnaces etc. The third application relates to how reliability can be improved by combining asset and process information. It’s applied in downstream rolling processes to analyze coil and process data in different phases, make correlations and label the operations data, and then use this labeled data to make predictive models. Some of these models are also prescriptive, providing the operator with exact action needed to avoid an anomalous situation.

Nikolaos Matskanis, CETIC ASBL, Belgium

Co-Author:
Guillaume Ginis, CETIC ASBL
Sebastien Dupont, CETIC ASBL
Rami Sellami, CETIC ASBL

Abstract:
Steel production involves separate manufacturing sites for each production phase and various stakeholders in the supply chain. All these sites are consuming and producing heterogeneous data that is often not efficiently exploited (no data aggregation, coalition), which impede the added value of a global overview of processes, quality and security assessment. In addition the growing use of automation and interconnection of Cyber-Physical Systems causes an increase of the attack surface and new challenges and security risks for industrial control systems.A platform with global overview of production quality and security over multiple sites that is multi-tenant and multi-actor and supports the aggregation/integration of data, would facilitate the anomaly detection in all stages of production and plants involved. Additionally allow application of remediation strategies to all involved sites. We propose a solution based on the FADI framework for deploying and orchestrating a Big Data management and analysis platform for each plant in the production chain. Such platform instance is called a federated FADI instance. Then, a global, federal FADI instance will be configured in order to communicate with the federated instances and combine received data for ensuring an overall overview on the production chain and anomalies detection. By interconnecting these instances, we will obtain a FADI Federation. FADI leverages the Collaboration, Automation, Lean, Measurement and Sharing principles of the DevOps approach to ensure that software is produced with a high level of quality and speed by integrating development (Dev) and operations activities (Ops). In order to address the new security threats, the FADI framework will be augmented with security services to secure the software development life cycle, improving the immunity of the system. This DevSecOps approach automates security activities in the software continuous integration and deployment pipeline including security response processes for assisting operators and security remediation processes using the FADI Vacsine tool.

Joachim Gnauk, PSI Metals GmbH, Germany

Co-Author:
Jonas Meinke, PSI Metals GmbH
Jan Guhl, Gestalt Robotics GmbH
Robert Piontek, GEFERTEC GmbH

Abstract:
The KIKA-IPK project (funded by the German Federal Ministry of Education and Research) aims to provide a cloud platform as a standard for industrial AI applications. This platform will interconnect industry partners and AI third party service providers in such a way that specific problems in production can be analyzed via this platform in a standardized way. The resulting AI application either will be available to the industrial customer remotely or deployed to the on premise system for offline use. The research project aims at developing an AI cognition support system for in-process control, which will enable a more resource efficient process and material configuration through self-learning correlations of signal characteristics with process properties. The machine operator's empirical knowledge of the connection between tangible quality features on the one hand and process characteristics on the other is modelled by machine learning methods. This is demonstrated by the example of additive manufacturing of steel parts.

Dieter Bettinger, Primetals Technologies Austria, Austria

Co-Author:
Martin Schaler, Primetals Technologies Austria
Petra Krahwinkler, Primetals Technologies Austria
Christian Tauber, Primetals Technologies Austria
Angelika Klinger, voestalpine AG
Harald Fritschek, Primetals Technologies Germany
Christoph Feilmayr, voestalpine AG
Magdalena Schatzl, K1-MET GmbH
Clemens Staudinger, voestalpine AG
Ross Goldberg, Midrex Technologies, Inc.

Abstract:
When using AI-based results for decision making or decision support, the reliability and a basic understanding of the underlying reasoning process is essential. Due to the involved complex metallurgy, thermodynamics and material parameters, modelling ironmaking processes with first principles methods is demanding. Artificial Intelligence (AI) and other data driven methods offer solutions for such complex systems. While AI- Algorithms are powerful, they tend to be black boxes. This can be overcome with Explainable AI and by considering Meta-Information. In this paper we present, how successful AI based applications for sinter plants, blast furnaces and direct reduction plants are built using such transparency techniques and how they are integrated into state-of-the art decision-support systems.

Guylaine Laforest, Corem, Canada

Co-Author:
Mathieu Dubé, Corem

Abstract:
The global context of action against climate change brought the iron ore producers and steelmakers to engage in ambitious plan for GHG reduction. The direct reduction process is part of numerous steelmaker’s GHG reduction plans consequently this topic is increasingly studied - especially cases where green hydrogen would be used. To ensure that various iron ore products will be performing adequately in either typical or future alternative DR reduction processes, a test evaluating readily their quality, under industrial representative conditions, should be available. This paper presents an updated laboratory scale test method allowing to study direct reduction of iron ore products under conditions close to industrial scale. The updated test allows the use of simulations as input conditions, is non-isothermal, allows for changes in gas concentrations and includes less typical species such as water vapor and CH4. The updated test method follows the impact of direct reduction on pellet performance such as reducibility, metallization, fines generation, pellet deformation, clustering, microstructure, and carbon pick-up.

Suneeti Purohit, Swinburne University of Technology, Australia

Co-Author:
Mark Pownceby, Commonwealth Scientific and Industrial Research Organisation
Akbar Rhamdhani, Swinburne University of Technology
Isis Ignacio, Swinburne University of Technology
Geoffrey Brooks, Swinburne University of Technology

Abstract:
Magnetite ores have the significant advantage of being able to be easily concentrated via magnetic separation, which is now becoming even more important as there is general shift towards DRI processes away from Blast Furnace ironmaking. For many DRI processes, any gangue in the ore is retained in the product, which is expensive to remove via electric melting, so minimising gangue in the ore is an economic priority. In the current ironmaking technologies, it is common to prepare magnetite ores for processing by firstly oxidising to hematite during pelletisation and sintering. This oxidation is carried to improve the reducibility of the iron ore for the subsequent ironmaking process. This improvement in the kinetics comes at a cost in terms of CO2 generation and/or consumption of Hydrogen (an expensive reductant). It is estimated that up to 130 kg of CO2 could be saved by not oxidising magnetite if the issue of reducibility could be addressed. Researchers at Swinburne University of Technology, in collaboration with CSIRO, has been studying how to improve the reducibility of magnetite ore by combining magnetite with lime and measuring the subsequent physical properties and reducibility. Lime is required in the steelmaking process, so introducing lime in the agglomeration step should not necessarily add cost. Substantial testing under laboratory conditions of different combination of magnetite with lime and other gangue oxides (alumina and silica) to form both pellets and sinter have shown that addition of lime (up to 7 wt.%) can significantly increase the reducibility of magnetite without sacrificing important mechanical properties required for subsequent ironmaking operations. Studies using Hydrogen as a reductant, have come to similar conclusions. This paper will summarise the key findings of this work and explore how these findings could be commercially exploited.

Alexandre GonÇalves Andrade, Métal 7 inc., Canada

Co-Author:
Alexandre Goncalvez Andrade, Métal 7 inc.
Steve Beaudin, Métal 7 inc.
Gaetan Lavoie, ArcelorMittal Mining Canada

Abstract:
The roller screening process plays a crucial role in determining the efficiency of the overall pelletizing operation. The screening efficiency directly impacts the pellet bed permeability in the induration furnace, which in turn affects its performance. The segregation concept is a recent innovation in the industry that has proven to increase productivity and quality of fired pellets, while also reducing energy consumption. The implementation of this concept can lead to significant financial benefits, but also turn out as an efficient way to help pelletizing plants to reduce their carbon footprint. The paper will highlight the principles of these technologies and present its real operational performance compared to a typical screening equipment.

Mohammed Liaket Ali, German Aerospace Center, Germany

Co-Author:
Uwe Riedel, German Aerospace Center
Quentin Fradet, German Aerospace Center

Abstract:
Full-fledged computational modeling of Direct Reduction (DR) reactors encompasses single pellets models and the step-wise scaling-up to industrial-scale reactors. The specific focus lies here on scale-up from a single iron ore pellet to a fixed-bed reactor model. However, this process poses several challenges like, a) Synthetic packed-bed structures need to be generated instead of a realistic image-based method due to the high cost, b) Good quality mesh for multi-pellet fixed bed is difficult to generate and c) Scaling up to a CFD environment is cost-intensive. Furthermore, the correct modeling of transport and kinetics-related processes for a single pellet is a prerequisite for a meaningful scale-up. This has not yet been demonstrated. In this work, the chemistry and transport data for the reduction of single iron oxide pellets with H2 gas, obtained from a previously developed 1D solid porous model will be used. The purposes of this article are 1) Proposing a CFD model that reproduces single pellet reduction experiments with H2 gas for wide experimental conditions in a 3D-CFD environment. 2) Computationally generating a random packing of 212 industrial pellets (0.5 kg) by applying the discrete element method (DEM) to simulate a lab-scale fixed-bed reactor. 3) Creating a 3D domain, based on the particle position data from the previous step and meshing the pellets and the voids among them in different refinements. 4) Reproducing a multi-pellet fixed-bed experiment with pure H2 from literature. 5) Investigating the effects of temperature variations in the bed. In this way, the concept of scaling up to multi-pellet fixed bed model simulation with H2 will be demonstrated successfully.

Aintzane Soto, Sidenor Investigación y Desarrollo, Spain

Co-Author:
Ivan Muñoz, 2.0 LCA Consultants
Maren Sollbach, Forschungsgemeinschaft Feuerfest e.V.
Christian Dannert, Forschungsgemeinschaft Feuerfest e.V.
Maria Arostegui, Tecnalia Research and Innovation
Abel Calepastegui, Tecnalia Research and Innovation
David Maza, Sidenor Investigación y Desarrollo

Abstract:
Management of ladle refractory waste in European steelworks currently often lacks systematic and integral solutions, with a great part of it being dumped into landfills in many countries. At the same time steelmakers are worried about ladle refractory costs but the improvements are achieved by partial assumptions or trial and error. A RFCS Circular Economy project, based on a 4R´s model, answers to this situation by combining the reduction of refractory consumption with the reuse, remanufacture and recycle of ladle refractory brick waste. The first scientific approach of the European E-CO-LadleBrick project is based on the Reduction of the refractory waste from ladles by optimising the ladle life. To this aim, a “low cost” 3D laser scanner that integrates the technologies Time-of-Flight and Phase-based has been developed. The information of the ladle refractory remaining thickness, obtained heat by heat in hot conditions, was combined with process variables to develop a prediction model of the ladle useful life and wear rate. A commercial equipment was used in order to generate additional data to feed the prediction model, and analyse the performance of the new 3D laser scanner. The second approach aims to optimize the valorization of worn ladle bricks after their use by means of finding suitable applications and calculating their benefits and restrictions, and implementing a data-based decision mechanism for best valorization in either Reuse, Remanufacture or Recycle. A total of 32 new applications were identified and implemented in two Decision Algorithms (one for magnesia materials and one for alumina based refractory waste) that include information about the optical and technical assessment of the refractories and the economic and environmental impact of the possible applications. LCA and LCC were used throughout the project to determine the environmental and economic benefits associated to this 4R approach.

Bruno Touzo, Calderys Belgium, Belgium

Co-Author:
emmanuelle Henry Lanier, Imerys S.A.
Laurence Canton, Calderys

Abstract:
Sustainability has become an integral part of products and processes. Refractories and other minerals used in the iron and steel manufacturing play an important role and need to bring their contribution to help reduce the environmental impact of the industry. A methodology was developed in Calderys to assess the life cycle of their product, from cradle to gate. It is aligned with the WBCSD framework, consistent with ISO standards and used quantitative and qualitative indicators. This paper will present the methods, some results and how this can help Calderys optimize new products and solutions sustainability.

Alexander Schlemminger, QuantoLux Innovation GmbH, Germany

Abstract:
Make the slag and the steel makes itself. This phrase illustrates the important role of slag in steel making. In particular, the increasing efforts in the direction of resource efficiency lead to an increasing demand for accurate slag work. DRI, alternate fuels and secondary raw materials on all routes lead to the import of more and more undesirable elements into the manufacturing process. On the other hand the composition of the slag was one of the last great unknowns of the steelmaking process (at least in-situ). Various workarounds tried to mitigate this issue more or less successfully. However, workarounds can not meet the ideal solution and they do not solve to the actual problem. For this reason, the confidential_steel_plant_disclosure_in_spring_23 has decided to test the fast slag analysis with laser OES. First in the context of a test setup in the central laboratory. After an adaptation period of approx. 2 months, slag samples are analyzed in daily use within approximately 17 seconds. Including sampling, sample shipment In this way, slag work can be carried out virtually without any waiting time on the basis of precise analysis results. In this way, slag work can be carried out virtually without any waiting time on the basis of precise analysis results. Due to the substantial added value, 2 devices have been purchased in spring 2023. The associated fast and precise adjustment of the slag has been proven to increase the cleanliness of the steel which lead to a reduced scrap rate in the end of the line. Furthermore, the tap-to-tap time in the ladle furnace has been reduced by an average of around 4 minutes, which in turn results in corresponding energy savings and increased yield. All in all, the investment in the fast slag analysis thus paid for itself within 5-6 months.

Sanjeev Manocha, LanzaTech, United States

Co-Author:
Tobias Plattner, Primetals Technologies Austria
Alexander Fleischanderl, Primetals Technologies Austria
Wim Van Der Stricht, ArcelorMittal

Abstract:
The Iron & Steel industry is in the decarbonisation era facing significant regulatory, political and technical challenges. Moreover, with aging Blast furnaces due for reline, steel mills are at critical decision-making moment to pick the most economic and sustainable solution. We believe that eliminating carbon emissions will be achieved through the integration of multiple technologies to deliver bespoke solutions suited to local conditions. Amongst the options is an innovative carbon capture and use technology developed by LanzaTech. LanzaTech converts carbon-rich gases into sustainable fuels and chemicals by a process of gas fermentation, with biocatalyst that feed on gases. LanzaTech’s naturally-occurring biocatalyst has been optimized to provide economic routes to ethanol and other chemicals from a variety of carbon-rich gas streams, including industrial off-gases from steel and ferroalloy mills, agricultural or MSW waste, and even CO2 from Direct Air Capture (DAC). By capturing the carbon contained in these gas streams, LanzaTech’s gas fermentation process reduces industry carbon emissions whilst producing chemical building blocks like ethanol that can be used directly for cleaning products or fragrances or converted to sustainable aviation fuels or the key ingredients needed for a broad range of consumer products including detergents, packaging and textile fibers. Products made with LanzaTech’s process offer an improved environmental profile and reduce greenhouse gas emissions by over 70% when compared to equivalent products derived from fossil fuels. This is the circular economy in action. LanzaTech technology has been successfully deployed in 3 commercial operating facilities at a steel and 2 ferro alloy mills, with 7 additional commercial plants in construction and several more in the engineering phase. The first European commercial scale plant, Steelanol, is soon due for commissioning at the ArcelorMittal Ghent combined with the Torero biomass project, with the objective of producing 80 million liters of bio-ethanol/year.

Stephane Mehrain, Fives Group, France

Abstract:
In current fast-evolving markets, Steelmakers are facing two types of simultaneous challenges. The first is related to new products and processes which require higher performance technologies and new digital solutions whereas a second challenge is overlapped with the need for green operations. Deep emission reductions are not achievable without innovation in technologies and materials. While innovative technologies are under development to use hydrogen, electrification and carbon capture, use and storage (CCUS), most of potential emission reductions are today coming from improvements in technology performances and in material efficiency. This paper presents the technology pathways to decarbonization and how innovations in technologies and materials contributes to both challenges through some examples in various fields of carbon steel and electrical steel processing. These advanced process technologies and digital solutions offer new avenues for steelmakers to expand their portfolio to higher-added value products, and to boost the productivity and environmental performance of their operations.

Alessandro Della Rocca, Tenova S.p.A., Italy

Co-Author:
Claudio Leoncini, Tenova S.p.A.

Abstract:
The European Green Deal, the Paris Cop21 agreement and the ‘Fit for 55’ climate package all set ambitious targets in terms of greenhouse gas emissions reduction. Consequently, European iron and steel producers need a paradigm shift to fulfill environmental regulations and to carefully evolve their processes towards low-carbon footprint technologies without losing competitiveness or profitability. To this end, both steel production stages, Upstream (up to liquid steel) and Downstream (from liquid to solid steel), need to implement an evolution or replacement of current technologies. Reduction of iron ores remains the most carbon intensive process and several technologies are currently under scrutiny for minimizing its carbon footprint. Anyway, more than 40% of European steel comes from scrap recycling with direct carbon emission intensity of about 130 kgCO2e/ton for the Upstream portion. In this case, reheating and heat treatment processes in Downstream, accounting for 50-190 kgCO2e/ton depending upon the product type, cover a relevant fraction of total direct carbon footprint of steel products. Consequently, the decarbonization of electric steel production must also take into account hot rolling and heat treatment processes. In this energy transition scenario, Tenova proposes a stepwise solution to the decarbonization of heating furnaces. After a first step of thermal efficiency optimization of existing equipment, electrification is pursued as far as possible to maximize energy efficiency. This is possible only up to a critical temperature, where other process constraints (scale formation, heating efficiency, production flexibility) come into play. Hydrogen and non-fossil fuels combustion are required for the final temperature increase, while also providing a protective atmosphere against surface oxidation. The sequence of implementation of these energy transition steps follows the availability of resources as foreseen in the energy transition scenario for Europe, thus providing to steelmakers a low-risk implementation of steel production decarbonization.

Sergio Martinez Muniz, Fives Stein, France

Abstract:
Following the global trend towards higher environmental sustainability/green industry, steel processing plants continue to develop new technologies, with new slab reheating process technologies offering major opportunities to help reach green steel targets, not only to minimize the carbon footprint but also to reduce plant operational expenditure. This paper introduces new equipment and services for reheating furnaces to reduce energy consumption, scale production and emissions. Multi-fuel combustion (including hydrogen) and energy recovery systems are fundamental new technologies that will also be reviewed.

Sethu Ramalingam, Danieli Corus B.V, Netherlands

Co-Author:
Peter Klut, Danieli Corus B.V

Abstract:
Blast furnace top gas contains dust particles which are removed in two stages in order to use it further as fuel gas. Coarser dust particles are removed in the first step using gravity or cyclone dustcatchers and the finer particles are removed in the second step (dry bag filter). The temperature in the first step should be in the range of 115°C to allow optimum separation efficiency and avoid condensation of moisture. For the secondary cleaning, the temperature window is narrow that it shall neither damage the filter bags nor the gas loses its calorific value, requiring a conditioning tower in-between to cool the gas in case of surges of hot gas. The top gas is transported to the gas cleaning plant via various refractory pipes (offtakes, uptakes, downcomer and raw gas main). Hence the choice of the insulating refractory is critical for the smooth and optimal performance of the entire gas cleaning process. In this study the effect of GCP refractory is investigated through series of three-dimensional CFD models using commercial software Ansys Fluent. The physical refractories and the steel shells are included in the flow model enabling conjugate heat transfer (CHT) from the hot gas to the solid walls. As the flow field and boundary layers are predicted in better fashion the heat transfer coefficients are predicted near accurately in CFD. Performance of the refractory is studied through steady-state calculations but during blast furnace operations a peak in the gas temperature occurs for short period of time, which are analyzed through series of transient state calculations. The solid wall time scales are too low bottlenecking the computation time, which is tackled by several modelling techniques. Eventually the model is validated with an overheating (of the refractory) incident that occurred recently at a blast furnace.

Peter Klut, Danieli Corus B.V, Netherlands

Abstract:
Dry blast furnace gas cleaning technology offers great economic advantages when compared to traditional wet gas cleaning owing to its improved energy efficiency, lower cost, reduced plot space, and practically eliminated water consumption. Given the improved operational economics and – in some areas – the physical or economic scarcity of water, steel producers are shifting towards the application of blast furnace gas cleaning systems, in which the wet scrubber is replaced with a dry second gas treatment stage. The Danieli Corus solution is based upon proven technology that has been applied numerous times for cleaning aluminium smelter gases and anode baking fumes. The system consists of a gas conditioning tower, reagent injection system and (pressurized) filter modules with low pressure pulse cleaning. Currently, Danieli Corus is implementing this technology for three greenfield blast furnaces in India. This article presents the advantages of the proven technology as well as some improvements that will be applied during the ongoing projects. These improvements include steam reheat of (cold) blast furnace gas, single phase water injection in the conditioning tower and two stage countercurrent absorbent injection.

Ritesh Mishra, Jindal Steel & Power Angul Odisha, India

Co-Author:
Damodar Mittal, Jindal Steel & Power Angul Odisha India
Nadeem Khan, Jindal Steel & Power Angul Odisha India

Abstract:
Jindal Steel and Power, Angul commissioned its first blast furnace of 4554 m3 in May 2017 at Odisha, India. This Blast Furnace has achieved productivity of 3.16 t/m3 of working volume/day by producing more than 12000 tons of hot metal in a day. Productivity improvement of large blast furnace is achieved by improving permeability inside the cylindrical structure of furnace by changing Sinter chemistry based on alumina percentage as higher alumina deteriorate the physical properties of Sinter, reducing fines and moisture input in terms of kg/thm, Modifying burden mix blending in main charging conveyor. This approach helped to increase oxygen enrichment with coal injection in the furnace to increase productivity.

Alexander Schmitz, Paul Wurth S.A., Luxembourg

Co-Author:
Lijia Wu, AG der Dillinger Hüttenwerke
Juraj Micák, Paul Wurth S.A.
Cédric Schockaert, Paul Wurth S.A.
Rongshan Lin, AG der Dillinger Hüttenwerke
Dieter Senk, RWTH Aachen University
Alexander Babich, RWTH Aachen University
Jean-Paul Simoes, RWTH Aachen University

Abstract:
The ironmaking industry is nowadays facing the great challenge of process optimization and transformation regarding the current ecological and economic requirements. Since the blast furnace is still the main facility for metallic iron production, a stable blast furnace operation aiming at lowering reducing agent consumption remains the main target in the daily business. Thus, a well-controlled blast furnace thermal state should base on a reliable thermal state prediction. Compared to the silicon content in hot metal, the hot metal temperature is considered to be more representative of the current thermal state. Hence, for model fine-tuning, many thermal state prediction models especially data-driven models require not only high measurement accuracy of hot metal temperature measurement but also enough datasets. After the successful commissioning of the multi-wavelength pyrometer for continuous hot metal temperature measurement on ROGESA blast furnace NO. 5, a new machine learning model is developed and its performance is compared with the model that is based on traditional immersion lance measurement. This newly developed machine learning model will be integrated into the current running expert system (BFXpert) platform for developing a rule-based thermal control model

Jörg Adam, VDEh-Betriebsforschungsinstitut GmbH, Germany

Co-Author:
Christoph Thaler, voestalpine AG
Ramona Eßbichl, voestalpine AG
Christian Rittenschober, voestalpine AG
Andrej Johnen, thyssenkrupp Steel Europe AG

Abstract:
The damage of a blast furnace tuyere is an unpredictable incident, happening in average between 30 and 100 times a year. As a result, two hours, in some cases up to eight hours shut down are necessary to change such cooling elements. Production loss, extra coke and steam for shut down increase the costs of hot metal (HM) production. Unplanned stoppages due to damages at the blast furnace tuyeres also cause additional emissions like CO2 etc. In the last decade BFI, in cooperation with various national and international partners, developed innovative systems for the observation of BF tuyere operation and the protection of BF tuyeres. The objectives were to generate advanced knowledge about tuyere damage mechanisms by the development of innovative systems for the monitoring of BF tuyeres during operation and to point out measures to extend BF tuyere operating life. The presentation will focus on:  BF measuring tuyeres with fibre optical temperature measurement  Optical monitoring system The presentation gives an overview about the investigations, findings and results of different national and international projects.

Hauke Bartusch, VDEh-Betriebsforschungsinstitut GmbH, Germany

Co-Author:
Andreas Feiterna, AG der Dillinger Hüttenwerke
Dan Iulian Durneata, AG der Dillinger Hüttenwerke
Thorsten Hauck, VDEh-Betriebsforschungsinstitut GmbH
Yalcin Kaymak, VDEh-Betriebsforschungsinstitut GmbH

Abstract:
The wear of the blast furnace hearth lining defines its campaign life. Due to the excessive costs of the relining, this is one of the most important economic factors of blast furnace ironmaking. As current state of art, hearth wear cannot reliably be measured directly. It is deduced from the temperature measurements in the refractory wall. Increases in the maximum observed temperatures are interpreted as additional wear. Nevertheless, the analysis of hearth wall temperatures suggests that other operational factors such as thermal hearth state and liquid flow also affect those temperature readings. Due to the harsh environment inside the hearth, it is impossible to directly measure factors describing such hearth processes. Dillinger BF5 is equipped with deep thermocouples reaching more than 1.6m inside the refractory. Dillinger and BFI have developed data streaming techniques enabling analysis of data from such thermocouples with comparable high time resolution of a few seconds. In parallel, Dillinger has performed continuous temperature measurements of the tapped hot metal. Applying methods from data science like analysis of data clusters and search for correlations, repeating temperature fluctuation patterns have been found. These patterns were related to either the tapping regime or to hot blast stove changes. The comparison of the process data distributions with and without such patterns provided valuable information on the inner hearth processes and the health of the hearth lining. This enables better and more reliable monitoring of the blast furnace hearth state.

Thiago Wandekoken, Lumar Metals, Brazil

Co-Author:
Paulo Hopperdizel, Lumar Metals
Igor Rana, ArcelorMittal Barra Mansa
Gerson Morais, ArcelorMittal Barra Mansa
Fábio Moreira, ArcelorMittal Barra Mansa
Marco Almeida, ArcelorMittal Barra Mansa
Arthur Ramalho, ArcelorMittal Barra Mansa

Abstract:
After about two and a half years of interruption in production, encouraged by the growing global demand for steel consumption and the prospects for economic growth, the ArcelorMittal Group decided to resume operations at the AMSF Barra Mansa steel mill. The AMSF Barra Mansa plant is equipped with two Electric Arc Furnaces (EAF), each with a capacity to produce 50 tons of steel per heat and a Continuous Casting Machine (CCM). However, the ArcelorMittal Group's planning was to carry out the resumption of the plant operations gradually and according to market movements, so, at first, the plan was to restart only one of these two furnaces, the EAF #2. The first month operation showed that several KPIs were out of goals combined, like power on, tap to tap, electric energy consumption, oxygen consumption and others. This paper aims to present the teamwork carried out between Lumar Metals and ArcelorMittal after the commissioning of EAF #2, implementing the reengineering of the chemical package equipment and adjustments of the electrical and chemical program until the achievement of the results committed to the board of the ArcelorMittal.

Iraj Salehi Arashloo, BARSOO Engineering Company, Iran, Islamic Republic of

Co-Author:
Farnaz Niknam Moghaddam, BARSOO Engineering Company
Delaram Radmehr, BARSOO Engineering Company
Ali Mohammad Monfared, BARSOO engineering company
Iraj Salehi Arashloo, BARSOO Engineering Company
,

Abstract:
In Electrical Arc Furnace (EAF) melting process, foamy slag quality has a key role in green steel production. A good quality of foamy slag helps to save energy, decreases graphite electrode consumption and enhance the refectory service life. Foamy slag quality is defined by its chemical and physical properties such as basicity and viscosity. By control of additives injection rate, good quality foamy slag could be obtained. In our research, a neural network model is designed and trained to estimate the rate of additives injection for achieving good quality foamy slag in the DRI based steel making, results of the research is presented in this paper. Due to effect of multiple variables in making of fully foamy slag, the “Multi Task Learning Model” has been considered. The neural network has been designed and trained with a specific architecture using real historical data which are related to those heats that had good basicity of slag. The data are belong to a steel making plant in Iran. There are three key factors that indicate quality of the foamy slag, one is noise made during melting process, another is slag height and the last is the total harmonic distortion (THD) Therefore, the network is trained by: - Additive weights - THD of voltage and current - the 7th current harmonic. The foamy slag process has been simulated using this model. The result shows that the trained multi task neural network improved remarkable percent of additive injection rate compared with the operator decision.

Marcus Kirschen, RHI Magnesita, Germany

Co-Author:
Uxia Dieguez, RHI Magnesita
Jan Lueckhoff, RHI Magnesita
Verena Schmidt, RHI Magnesita
Markus Gruber, RHI Magnesita

Abstract:
The mandatory transformation of European steel production towards Green steel routes requires an increasing use of steel scrap and direct reduced iron. Consequently, new EAFs with large melt volumes are expected to meet the required production capacity at minimum CO2 intensity. With increasing melt volumes the impact of oxygen injectors to bath mixing decreases and additional stirring technologies are required for an optimum EAF process. Inert gas stirring is an established method to improve process control, energy efficiency, metal yield and melting time. In the following paper, the benefits of RHI Magnesita´s gas purging technology in EAFs are highlighted by means of transient CFD simulations; with special focus on the influence of the steel flow on refractory wear and hearth mix consumption. The observed process improvements are presented by industrial case studies covering EAFs fed by steel scrap, direct reduced iron and/or hot metal. The here shown process benefits are achieved at the same refractory consumption figures in contrast to competing EAF stirring technologies.

Thiago Wandekoken, Lumar Metals, Brazil

Co-Author:
Marssal Victorino, ArcelorMittal Resende
Hélio Oliveira, ArcelorMittal Resende
Iury Silva, ArcelorMittal Resende

Abstract:
The problem of electrode broken becomes frequent during the heats along 2020 during Electric Arc Furnace (EAF) operation, which had a very negative impact on the specific consumption of electrodes (kg/t) of the EAF. Given the strangeness of the events and the high cost of this raw material, a working group was formed to analyze the data and find the cause of the excessive amount of electrode breakage. This working group found a strong relationship between skull formation in some regions of the EAF and the electrode breakage. This paper aims to present the methodology used teamwork carried out between Lumar Metals and ArcelorMittal Resende in the characterization of the problem, planning and execution of actions to avoid the formation of skulls in the EAF and consequently to avoid electrode breakages. The gain was the reductions of 66% in the electrode consumption.

Randall Stone, Valmet Automation Inc., United States

Co-Author:
John Lewis, Connors Industrials Inc.
Chuck Krcmaric, Connors Industrials Inc.
Tom Connors, Connors Industrials Inc.

Abstract:
The vacuum tank degassing process (VTD) is used by steel makers worldwide to produce steel grades that must meet stringent customer quality requirements. Balancing VTD productivity while achieving the proper vacuum treatment level is a challenge, especially for deep vacuum treatment (~ 1 Torr or 133 Pa). Maintaining the proper freeboard is an important process parameter. If the rate of gas evolution is too great, the steel can foam up and over the ladle lip causing an overflow event resulting in safety concerns and downtime for cleanup or maintenance. This paper will discuss implementation and operational results of specialized Infrared (IR) camera/lens technology coupled with IR imaging and process control software for VTD operations. The system provides a real time view of critical molten metal behavior, stirring intensity, freeboard, metal level and rate of rise during the VTD process thereby enabling control software to avoid an overflow event. The specialized IR camera/lens system provides a clear image of the ladle and molten metal undisturbed by flame and flare. This requires strategic placement of the lens tip within the vacuum chamber, maximizing survivability while not compromising the gas-tight seal required to achieve deep vacuum treatment conditions. The IR image processing is performed real time. This yields an accurate determination of the metal level with respect to the ladle lip. The rate of rise is measurable, enabling a prediction of an imminent overflow event. Thereby the operator is alerted to the situation in time for corrective actions to be taken. Computer model verification is achieved by comparing alarm predictions to actual overflow events. Adjustable settings tune the model’s sensitivity to the specific installation. Future work includes implementing closed loop control to avoid the overflow event.

Bernd Kleimt, VDEh-Betriebsforschungsinstitut GmbH, Germany

Co-Author:
Waldemar Krieger, VDEh-Betriebsforschungsinstitut GmbH
Diana Mier Vasallo, Sidenor Investigación y Desarrollo
Asier Arteaga Ayarza, Sidenor Investigación y Desarrollo
Inigo Unamuno Iriondo, Sidenor Aceros Especiales

Abstract:
The Electric Arc Furnace (EAF) for scrap-based steelmaking will play an important role in near future to realise the transition towards Green Steel production due to its more efficient use of resources, lower carbon emissions and inherent circularity compared to the iron ore-based steelmaking. This work presents a practical approach for a Decision Support System for the EAF with real-time heat state monitoring and control setpoint optimization which has been developed within the EU funded project REVaMP and applied at the EAF of Sidenor in Basauri, Spain. The system consists of a dynamic process model based on energy and mass balances, including thermodynamic calculations for the most important metallurgical reactions like dephosphorisation and decarburisation, and a scrap characterization and scrap mix optimisation tool to estimate the scrap properties, which are critical for reliable process performance and accurate online process control. The underlying process models and control functions were validated on the basis of historical production and measurement data of a large number of heats produced at the Sidenor plant. Also, the applied model parameters were fitted using this data to further increase the prediction accuracy and to account for influences, e.g. during melting, that are otherwise difficult to model precisely. The model calculations are adapted in real-time to the performed measurements and analysis values to make best use of the information available during EAF heat production. Particular attention is paid to the modelling of the dephosphorisation reaction and the end-point control of the phosphorus content, as this is a critical parameter for production of high-quality steel grades along the EAF process route. The developed tools for Decision Support are integrated within a web application to facilitate their utilization and to provide impactful support for the plant engineers and operators.

Ion Rusu, BM GROUP POLYTEC S.p.A., Italy

Abstract:
Depending on furnace, BF/BOF/AOD or EAF or LF/VD/VOD, a tailor made robotic cell can replace human operator in sampling and measurement operations. The fully automated solution is able to perform complex trajectory based on the space available and Repetitive and reliable tasks like measurement, sampling, automatic charging of cartridges from dispenser, precise bath level measurement using the robots coordinates, steel sample separation for the sample laboratory. A lances warehouse allows to easily manage the different tools. The robot for EAF sampling and measurement can also be equipped with a lance, developed by Tenova & Polytec, with a camera able to perform the internal inspection of the EAF furnace. In the refining area, the system is engineered for the process and the footprint available (LF/VOD/RH). It can perform multiple tasks like: temperature measurement, sampling, level measurement, hydrogen measurement.

Anna Mayrhofer, Primetals Technologies Austria, Austria

Co-Author:
Xuedi Schmoelzer Deng, Primetals Technologies Austria
Thomas Reindl, Primetals Technologies Austria

Abstract:
"In a ladle treatment station or ladle furnace station, calculation of desulfurization, aluminum fading and homogenization is a difficult task due to the dynamic nature of molten steel/slag movement controlled by bottom stirring. In traditional model, those parts are normally calculated separately with individual parameter setting. The traditional way needs a lot of parameter adjustment work for different project, due to different ladle size and plug conditions. In the recent developed level 2 model by Primetals Technologies, the reactions, which are led by kinetic movement of molten steel/slag, are considered as a whole part. The key to the new method is a kinetic model which predicts circulation movement of molten steel/slag with regard to ladle size, plug condition, bottom stirring flow rate and height of steel/slag. The result of the new kinetic model gives on average a more precise prediction of sulfur and aluminum value during treatment."

Nicholas Walla, Purdue University Northwest, United States

Co-Author:
Chenn Zhou, Purdue University Northwest
Steve Ryan, NLMK Indiana
Xipeng Guo, Purdue University Northwest

Abstract:
In this work, a 3D transient Computational Fluid Dynamics (CFD) model is developed to simulate arc heating process in a steel ladle. Three phases, air, slag and steel, are considered using Volume of Fluid (VOF) model. Temperature dependent material property are considered. Two off center slit plugs are placed at bottom of ladle. Discrete Phase Model (DPM) model is used to calculate bubble movement, coalescence and breakup during rising process. Heat transfer including radiation from electric arc to multiphases are modeled. Three electrodes are placed at top of ladle. Electrodes submerge length in slag layer is 3 inches. The channel arc model is employed to calculate the characteristics of electric arc. Al2O3 refractory brick and MgO-C refractory brick are include to calculate the heat loss through refractory wall. Based on the results, the dead zone of fluid flow is identified. Flow induced wall shear stress and multiphase distribution are observed. Temperature evolution in the bulk steel and slag are investigated. Temperature profile on refractory wall are studied. As for validation, temperature historical data is provided by industrial. Temperature measured at 2 ft away from refractory, 1 ft below steel surface and above one of the plug. Simulation shows good agreement on temperature between CFD prediction and industrial measurements.

A .Nicholas Grundy, Thermo-Calc Software AB, Sweden

Co-Author:
Lina Kjellkvist, Thermo-Calc Software AB
Ralf Rettig, Thermo-Calc Software AB

Abstract:
There is currently a distinct trend in AI / ML type simulations of the steelmaking and -refining process. Such approaches can very accurately predict the outcome of steel processing, however there are 2 major drawbacks: 1) They only work well in the limits, within which the algorithms have been trained. 2) They are largely a black-box approach, where cause and effect remain hidden. The alternative approach are physical models, that are based on general principles like conservation of mass, conservation of energy, etc… that hold true far outside the narrow window, inside which steel processing is mostly constrained. This means predictions can be made on what happens when the process leaves this window. While such an event might be rare in a well-controlled industrial environment, it is crucial to know what happens, as the potential damage caused if appropriate action is not taken, can be massive. A further advantage of physical models is that the influence of distinct steps in the processing can be analysed separately, as they need to be explicitly implemented in the physical model. Finally -unlike an AI / ML model, a physical model will also provide information for properties for which no experimental measurements have ever been performed. In this paper, a physical model for steelmaking and -refining is presented, that uses thermodynamic equilibria calculated with Thermo-Calc and the CALPHAD type steel and slag database TCOX12. Reaction kinetics are accounted for using the Effective Equilibrium Reaction Zone (EERZ) model. The model is commercially available as the Process Metallurgy Module within the Thermo-Calc Software package and already being used in academic and commercial research. Some application examples are given and if it shown how simulations can be run, directly using process data stored in a Level 2 system.

Mario Gelmini, BM GROUP POLYTEC S.p.A., Italy

Co-Author:
Ion Rusu, BM GROUP POLYTEC S.p.A.
Tiziano Bagozzi, BM GROUP POLYTEC S.p.A.

Abstract:
The fully automated robot performs safely, remotely and autonomously different tasks on the casting floor. The system is able to identify the nozzle position into the space using a 3D machine vision system, to position the ladle shroud, oxygen lance the nozzle in case of corks, to take temperature and sampling and to distribute powder on the tundish. A smart solution that improves operator's safety on red zone area and efficiency.

Alma Olivos, Tata Steel IJmuiden B.V., Netherlands

Co-Author:
Sonja Strasser, Primetals Technologies Austria
Oliver Lang, Primetals Technologies Austria
Martin Schuster, Primetals Technologies Austria
Dirk van der Plas, Tata Steel IJmuiden B.V.
Stephen Carless, Tata Steel IJmuiden B.V.

Abstract:
Mold thermal monitoring in continuous casting is essential for breakout prevention and to monitor process stability. Whilst useful, the number of thermocouples and coverage has been limited. Owing to these limitations, a mold containing Fiber Bragg Gratings (FBG) was developed to increase measurement resolution. This high-resolution grid provides the basis for various data analytics approaches to get a clear heat transfer picture and to characterize casting mold phenomena that until now have remained only accessible through modelling. We will present 3 main focus areas to gain better insights into the heat transfer picture. Firstly, an accurate temperature-based mold level measurement along the entire mold width has allowed to link mold flow with meniscus shape. Describing the meniscus shape has proven central to relate process parameters such as argon, throughput, and electromagnetic flow control to surface quality. Secondly, the information on heat transfer along the slag pool and meniscus area has allowed to observe localized performance of the melting powder behavior. This has served as accelerator to evaluate mold powder performance. Third, having the full heat transfer picture has allowed to observe in a very early-stage other process problems such as uneven mold powder infiltration and possible rim formation. Among the advantages of using FBGs as thermal monitoring tool is the ability to collect the process status in real-time. This enables the analysis of the process with statistical and other data analytics methods in a shorter amount of time. For this we have developed an interactive app where the results of the analysis are summarized and visualized. This allows faster and better-informed decision making for process optimization and incident prevention. The information, knowledge and algorithm development coming from FBG mold monitoring has allowed to capitalize the use of FBG as thermal probes in form of process reliability and product quality improvement.

Sina-Maria Elixmann, RWTH Aachen University, Germany

Co-Author:
Dieter Senk, RWTH Aachen University
Markus Schäperkötter, Salzgitter Flachstahl GmbH
Peter Müller, Salzgitter Flachstahl GmbH

Abstract:
Surface quality of semi-finished products is mainly formed in the mold. Thus, the quality of the slab can be well adjusted by the correct setup of the mold. To be able to analyze the dynamics of solidification of the strand in the mold during the process, fiber optics were implemented in the mold plates of the narrow and broad faces. In total 476 measuring points provide a good monitoring of the temperature field of all four faces of the mold. Measurements were carried out using the new fiber optic measurement technology. Local heat fluxes can be determined from temperature measurements, if the geometrical und physical properties of the heat transfer layers in the mold region are known. During the use of measurement technology, process parameters were varied, which lead to a different development of the temperature field. Thus, based on the temperature data, it can be estimated which deformation of the strand shell happen in the mold during casting. At the end, the significance and transferability of measured cold and hot spots in the copper plate for the strand shell is discussed.

Johannes Minovsky , Vesuvius Europe, Germany

Co-Author:
Matthias Schmitz, Hüttenwerke Krupp Mannesmann GmbH
Thomas Heerink, Vesuvius
Thorsten Bolender, Hüttenwerke Krupp Mannesmann GmbH
Martin Kreierhoff, Vesuvius

Abstract:
The achievement of a sufficiently homogeneous solidification structure in the as-cast state already represents a decisive qualitative aspect in the production of high-alloy steel grades that are used for applications such as roller bearings, crankshafts, or components for the engine. The production of these applications belongs to the engineering long segment. Specific standards for round, square, and rectangular formats have been developed by the end customers to achieve the requirements for internal quality and mechanical properties. Over the years, when casting high carbon & high alloy grades, the use of an EMS (Electromagnetic stirrer) has become a standard. The declared goals for the semi-finished product of high-carbon grades are to achieve a high proportion of equiaxed area, to reduce segregation, and to avoid cavities in the as-cast product. A new generation of swirl designs was tested on the HKM round-caster, and the optimization was underpinned using CFD. The casting texture evaluation was analysed with the help of an Ultrasonic-Device and amazing features - achieved with Super Swirl - could be proved. Keywords: Engineering Long, Round-Caster, EMS, Equiaxed area, High Carbon grades, Stirring Effect, Super-Swirl, HKM, Crankshaft

Oliver Lang, Primetals Technologies Austria, Austria

Co-Author:
Martin Schuster, Primetals Technologies Austria
Bernhard Winkler-Ebner, Primetals Technologies Austria
Alma Olivos, Tata Steel IJmuiden B.V.
Krister Fröjdh , Proximion AB

Abstract:
"The installation of optical fibers with Fiber Bragg Grating sensors in the copper plates of a continuous casting mold, used for temperature sensing is getting more and more common. It has been proven to work in all types of casters like slab casters, casters with funnel molds for endless strip production and even in bloom casters. With several thousand of measurements points, optical fibers offer completely new insights into the casting process. With small distances between the Fiber Bragg Gratings and advanced evaluation algorithms, the mold level can be determined for the complete mold perimeter. The advantages of a temperature-based calculated mold level compared to electro-magnetic measured mold levels are shown. Electromagnetic mold brakes and stirrers are becoming state of the art to reduce inclusions and to achieve better surface quality results. Based on simulations, these electromagnetic devices are usually tuned to the desired operating conditions. However, in reality, there are many more influencing factors and disturbances such as clogging, so the actual steel flow is not known. With an indication of sub-meniscus speed and analysis of mold level and temperature distribution in the mold the Mold Expert fiber can help to characterize real steel flow and evaluate the influence of the electric field. Another area where this large number of measurement points can help is cast start. It will be presented how this critical event is monitored and how cast start breakouts can be prevented."

Mirko Javurek, Johannes Kepler University, Austria

Co-Author:
Sergiu Ilje, voestalpine Stahl GmbH

Abstract:
In bow-type continuous slab casters, non metallic macro-inclusions (size 50 to 200 μm) are concentrated in a small band over the strand thickness, also called „quarter depth inclusion band“. This effect was observed in measurements and can be explained theoretically by the bow geometry in combination with the upwards drift velocity of inclusions in the liquid steel due to the density difference. Measurements also showed that the inclusion distribution is often significantly inhomogeneous and asymmetric over the strand width. Theoretical considerations explain this effect by an inhomogeneous flow pattern in the bending zone of the strand. In this contribution, transient numerical flow simulations of the liquid steel inside of the strand with the scale resolving SAS turbulence model in combination with non-metallic particle transport are presented. The time scales of the flow fluctuations in the bending zone showed to be quite large. Therefore, one hour of the casting process was simulated, which requires about one year of computation time. Two cases without and with argon gas injection at the stopper rod tip were considered. The injected gas is assumed to form bubbles, that are transported with the liquid steel flow into the mold and influence the mold flow by their buoyancy forces. The results show irregular fluctuations of the inclusion distribution with alternating asymmetric profiles over the strand width, with time scales in the order of magnitude of several minutes, corresponding to strand length distances of several meters. The case with argon injections shows slightly lower peak concentrations than the case without gas injection.

Bahareh Najafian Ashrafi, K1-MET GmbH, Austria

Co-Author:
Alija Vila, Primetals Technologies Austria
Felix Lindbauer, Primetals Technologies Austria
Martin Barna, Johannes Kepler University

Abstract:
Continuous casting is the main method of steel production, with over 96 percent worldwide. Thus, optimizing this process can heavily impact the steel manufacturing costs. The application of electromagnetic fields in the continuous casting of slabs is a well-known method to control the flow field inside the cast strand. If applied properly, electromagnetic fields can result in an improved flow behaviour, consequently, minimizing the product defects. Electromagnetic fields are divided into two major categories: static and traveling magnetic fields. Electromagnetic Braking (EMBr) systems use static magnetic fields to stabilize the flow, especially in high casting speed situations. To control the molten steel flow more actively, travelling magnetic field systems with their greater capability to impact the steel flow were developed. Three different moving fields can be generated: Electromagnetic Level Stabilizer (EMLS), Electromagnetic Level Accelerator (EMLA), and Electromagnetic Rotating Stirrer (EMRS). Depending on the flow situation in the mould region, and the need for acceleration, deceleration, or stirring, each of these modes can be activated. Any combination of these traveling magnetic fields with static magnetic field is also possible. Although this combination makes the flow field much more complex, it provides the simultaneous flow control in the whole mould region (both above and below the submerged jets). The impact of EMRS without and with EMBR (combined mode) on the mould flow pattern were investigated in the current work. The results show that the surface velocities can be homogenized and increased due to EMRS. The combination with EMBr can cause homogenized surface velocities and reduced jet penetration length.

Qifeng Shu, University of Oulu, Finland

Co-Author:
Timo Fabritius, University of Oulu
Tuomas Alatarvas, University of Oulu

Abstract:
Non-metallic inclusions have critical effects on the properties and manufacturing process of steels. The amount, composition, morphology and size distribution of inclusions define the cleanliness of steel, which is the key to “clean steel”. In this work, a modelling framework for describing the evolution of amount, composition and size distribution of inclusions during refining and casting is established based on the thermodynamic-kinetic models and nucleation models. In order to calculate the evolution of size distribution of inclusions, the nucleation, growth and coarsening of inclusions are described by Kampmann-Wagner numerical model and the collisions and agglomerations are modelled by the population balance model. Both homogeneous and heterogeneous nucleation are accounted for. The model can be also employed to describe the evolution of inclusions during cooling and solidification by combining a solidification model. The models have been validated using both laboratory- and process-scale experimental data for aluminum deoxidation, reoxidation and inclusion precipitation during solidification. It is found that the supersaturation is the key for determining the dominant nucleation. During the inclusion precipitation with a high concentration of deoxidizing elements, e.g. Al, the homogeneous nucleation is dominant. In comparison, the heterogeneous nucleation and following diffusion is the most probable way to modify alumina into spinel and solid and liquid calcium aluminates. The present modelling framework will make it possible to calculate the evolution of amount, composition and size distribution inclusions during the whole process chain in steelmaking and casting, and therefore provide a valuable tool for process control in steel plants. Owing to the wide range of applicable cooling rates, the model is applicable not only for slabs but also for blooms, billets or thin slabs.

Keiji Mizuta, Primetals Technologies Japan, Japan

Co-Author:
Takanori Nagai, Primetals Technologies Japan
Hirokazu Kose, Primetals Technologies Japan

Abstract:
The cooling speed over a certain level and the consistency of temperature profile are essential for the thermal cycle in the continuous annealing line (CAL) for an advanced high-strength steel strip (AHSS.) Because this particular cycle usually involves multiple water sprays, optimization of the spray pattern and nozzle arrangement, which affect the cooling speed and temperature, is expected to complete the requirements.The test to cool a rotating hot drum is conducted numerous times with various spray patterns and nozzle arrangements on the experimental equipment that replicates the process in the subject cycle as necessary and sufficient. A heated steel drum is rotated at the speed corresponding to the running speed of the strip. The water films formed on the inner surface and the intermittent cooling process are produced under the almost same conditions as in the actual cycle in the CAL. For the horizontal cooling pass, the drum is placed in an inverted position and given an appropriate taper angle so that the vertical distribution of the water film thickness formed by centrifugal force due to the rotation simulates the distribution of the water film across the width of the steel strip.Through those trials performed enough times, the ideal spray pattern and nozzle arrangement to cool an 800℃ strip of 1 mm in thickness to 100℃ at 1000K/sec or better and within ±10K of temperature consistency are identified.

Simon Mittlboeck, Primetals Technologies Austria, Austria

Co-Author:
Georg Keintzel, Primetals Technologies Austria
Konrad Krimpelstaetter, Primetals Technologies Austria

Abstract:
"This paper deals with the development of a new technology for reducing and eliminating resonance vibrations in hot strip mills and thin-slab casting and rolling plants. The new system – called Vibration Dissipator - allows to stabilize and improve the overall process stability by reducing the vibration behavior of single finishing mill stands. The Vibration Dissipator is based on two combined physical effects. First effect represents the impact of a classical absorber, being an added vibratory element that is designed to “swallow” the resonance vibration. Second, an energy dissipating element which broadens the effective suppressing frequency range. The solution consists of special designed hydraulic elements, such as a combination of a capacity, a resistance and an inductance. This arrangement of design elements can be realized as a passive or semi-active energy dissipating hydraulic solution. A pure passive Vibration Dissipator was already successfully implemented on finishing stand 3 of an industrial hot rolling mill. The actual development targets focus on a semi-active concept with an adaptable hydraulic capacity. With this concept, it is possible to adjust the desired frequency of the Vibration Dissipator in a defined range. Since the frequency of these vibrations can change during the production, our concept allows a smooth adjustment to the actual frequency within seconds, in order to achieve an optimized damping effect. With our developed frequency identification system, it is possible to identify the actual frequency of the vibration which is currently appearing at the stand. Such a system consists of accelerometers and a sophisticated algorithm to evaluate the frequency. This frequency identification system is already implemented at another technological package from Primetals Technologies."

Ossama Sharaf El-Din, Al Ezz Dekheila Steel Co., Egypt

Co-Author:
Abd El-Moneim Sewaif, EZDK

Abstract:
Improvement of Material Yield in EZDK Wire Rod Mill Plant EZDK wire rod mill plant was supplied by the German plant producer SMS, started commissioning in 1986 with one strand which was upgraded in 1996 with the second strand to reach over 900,000-ton annual production for sizes ranging between 5.5~16 mm for low, medium and high carbon steel products. The improvement of the material yield in any rolling mill plant is crucial for improving efficiency and reducing costs. In EZDK wire rod mill plant, starting in 2019 an ambitious campaign was launched to optimize the wire rod yield figures. As yield is dependent upon many factors, such as cobbles, total scrap generation, crop loss and scale loss the campaign focused on many aspects in order to achieve its target. Both technical and managerial techniques were put into practice in order to minimize the wastes created during the product's manufacturing process, how to get sure that your getting the maximum output of the inputs (billets) through controlling the reheating furnace settings to reduce the generated scale, reducing the material cobbles, and minimizing the no. of defected/scrapped coils was the challenge. We are committed to providing accurate and timely information on the material wastes on daily/ weekly and monthly basis through developing a daily monitoring system that allows us to track material wastes in real-time, it wasn’t only about the technical points only but also how to change the minds of the people to believe that the reducing the wastes will make the difference. By doing this, we could reach to a worldwide figure in the material yield (98.0%) for two consecutive years (2020, 2021) according to Badische best practice study, achieving the second place worldwide, looking forward to do better through applying further improvements.

Michael Breuer, SMS group, Germany

Co-Author:
Georg Padberg, SMS group
Wolfgang Fuchs, SMS group
Heiko Reichel, SMS group

Abstract:
CO2-neutrality is the imperative of this time to protect and preserve our environment. The steel industry is particularly focused on it, because by its very nature the manufacturing processes are energy-intensive. For steel manufacturers, this requirement leads to strategic reorientation. As plant supplier, SMS group is challenged to develop and offer innovative solutions right across the entire process chain. One challenge is to identify and utilize all energy saving potentials in the production process. The second and major task is to substitute fossil fuels by electrification and by use of green fuels. The hot rolling process is comparatively energy-intensive. The largest consumer of energy is the heating process. A major focus thus needs to be placed on the interface between the upstream processes and the hot rolling process, where optimization measures for energy saving can be made. Also for the hot rolling process itself, it is important to evaluate each individual energy consumer for his optimization potential. For some process stages and components there are already proven solutions which gain new significance in the context of fossil free production and to tap into their inherent potential. One example is the installation of mandrel-less coilbox in the roughing mill area. A coilbox comes with numerous advantages and improves the process control. However, a coilbox reduces the overall plant length and the energy consumption in the finishing mill. Another example is smart descaling, which takes place in the roughing and in the finishing mill area. Smart descaling means width and steel-grade dependent descaling. The water pressure and the water volume are specifically controlled and applied, resulting in water and energy savings. These are just two examples, among other things - including new developments, which we intend to evaluate as part of the paper with regard to their energy saving potential.

Tim-Oliver Mattern, Carl Bechem GmbH, Germany

Abstract:
This paper covers the practical improvements that have been achieved in a tube mill just from changing from traditional grease to Polyurea technology. Tubes are either formed and welded or seamless rolled. Both processes require many steps and mill equipment that is exposed to load, heat and cooling fluids. In this harsh environment the equipment needs to work reliably without unexpected and expensive breakdowns. Most of the equipment is grease lubricated and while traditional greases have provided predictable performance in the past, their deficiencies often result in increased consumption to simply maintain basic reliability expectations.

Tizian Rotherm, SMS group, Germany

Co-Author:
Christian Dornscheidt, SMS group

Abstract:
In strip processing lines, the ends of the strip have to be joined together to form an endless strip, which is necessary for a continuous process. Laser welding fulfills this task perfectly. The X-Roll® laser welder is capable of welding a wide field of steel grades, even those deemed as hard-to-weld. This is possible due to the patented inductive heat treatment system. Other technical highlights are a low cycle time, automatic welding parameter calculation, the quality assurance system, and a fast knife cassette exchange-procedure. The laser source can be either a carbon dioxide or a solid-sate laser resonator. The solid-state laser offers advantages such as less operational costs and a more flexible design. Yet the carbon dioxide laser is the more established technology on the market. As part of our processing lines, the X-Roll® laser welder utilizes synergy effects to optimize and stabilize the production. The X-Roll® laser welder is not only confined to new lines, it can also be suited for a revamp in an existing processing line. Due to the slim design of the machine, the replacement of obsolete flash butt welding machines or older laser welding machines can be done with low effort. This enhances the variety of input material. Older welding machines are often not capable of welding modern steel grades in a reliable manner, since the alloying content of the strip material effects its weldability. The paper will include information about solid state lasers, weld-seam heat treatment, revamps, preventive maintenance and possibilities of digitization. Reference implementations will be shown as well.

Ryouta Kumagai, JP Steel Plantech Co., Japan

Co-Author:
Ryuta Kumagai, JP Steel Plantech Co.
Keizo Abe, JP Steel Plantech Co.

Abstract:
Recent metal plate and/or sheet, including ultra-high-strength steel for automobiles, are remarkably becoming high-performance (high-end). These materials tend to be conducted special treatment such as heat treatment which has not been performed in the past in the production process, and their flatness tends to be deteriorated. Consequently, the flattening ability of high-performance (high-end) metal plate/sheet, especially ultra-high-strength steel, has been insufficient in conventional leveling facilities, and more powerful and more accurate flattening facilities have been required. In response to this requirement, a new type hybrid roller/tension leveler and slitter combination facility (super hybrid leveler/slitter line), which has both tension leveler function and roller leveler function capable of handling a wide range of metal plate/sheet, was developed and put into the commercial operation. This document introduces the technology and outline of the new facility.

Karola Gurrath, Primetals Technologies Germany, Germany

Co-Author:
Matthias Kurz, Primetals Technologies Germany
Raphael Twardowski, thyssenkrupp Steel Europe AG
Klaus Loehe, Primetals Technologies Germany
Andrea Schmidt, Primetals Technologies Germany

Abstract:
By upgrading individual software components, steelmakers can continuously modernise their plants and achieve more sustainable quality production. An example of this is thyssenkrupp's recent upgrade of an advanced profile, flatness and contour control system into an existing third-party automation system. The new configuration consists of a level 2 set-up system and a level 1 real-time controller. In addition to fundamental quality improvements, the focus is on flatness guarantees, which are increasingly in demand from end customers. This article describes the virtualised system, the analysis tools and the digital twin in detail. Results are also shared, including the improvements to strip quality and the reduction in the number of further downstream processing steps required to achieve the desired product quality.

Friedrich Lücking, SMS group, Germany

Co-Author:
Helga Evers, SMS group / QuinLogic
Thorsten Claff, SMS group / QuinLogic
Michael Raus, SMS group / QuinLogic

Abstract:
Despite high capacities, the industry is heavily investing in new equipment for reasons of better product quality, additional grades, reduced CO2 and energy footprints. Given the complexity of new lines, regardless if it’s about Caster Host Strip Mill, PLTCM or CGL ensembles, achieving optimal production settings with all required processing variants and the typically reduced lot sizes in the Industry 4.0 world requires huge efforts and often takes longer than before. Fortunately, with all the instrumentation, measurement, and data capture technologies, advanced software concepts can be used to significantly speed up the start-up time. These software methods involve big data type of IT infrastructure as well as some of the most advanced machine learning methods. A unique aspect in this paper is the fact, that these advanced methods are not applied by specialists but directly through the operating personal – to achieve the best output of the new processing line. This paper will also use aspects from a new CSP® Nexus caster as well as a new CGL line.

Babak Taleb-Araghi, SMS group, Germany

Abstract:
Herringbone and diagonal-wrinkles / cross-buckles are related members of a family of non-trivial, visually stunning, and terribly confounding flatness defects. This family encompasses a spectrum of cascading complexity, ranging from a relatively simple, full width diagonal wrinkles to several varieties of multi-facetted, high-fidelity crosshatch patterns. These distortions form when a region of near flat (or lightly centerbuckled / loose) strip is subjected to planar shearing. The shearing stems from a variety of unrelated, and possibly cooperative causes (e.g., misalignments, camber straightening, asymmetric roll bite lubricity, transverse thermal gradients, etc.), forming an angled field of compressive strain (with respect to the strip’s longitudinal / rolling axis). Localized buckling spontaneously occurs when the work done in compressive straining (the act of physically displacing the material) exceeds the threshold condition of the strain energy required to deform the material (thereby achieving a minimum energy equilibrium). The most general form of manifest buckling is a highly ordered, self-assembling checkerboard-like pattern associated with classical thin plate buckling. The simplest variants manifest in a diagonal or chevron pattern. While the visual appearance of these lesser variants may have reduced complexity, the entire herringbone family shares the same underlying framework and physics. This paper examines the underlying physics and mechanics of the herringbone family by analyzing the formation mechanisms of relatively simple diagonal buckling. Classical mechanics and Mohr’s circle are employed to provide insight into how increased exit tension suppresses defect formation in the presence of the possibly cooperative causes.

Tae Jun Park, Hyundai Steel Co., Korea, Republic of

Co-Author:
Gang Won Lee, Hyundai Steel Co.
Hyeon Woo Park, Hyundai Steel Co.
Myoung Hwan Choi, Hyundai Steel Co.
Yun Kyum Kim, Hyundai Steel Co.

Abstract:
So far, many researchers have made various efforts to improve the surface quality for automotive exterior sheet steel. Dross and Ash defects, which are major defects, must be effectively controlled to ensure the surface quality of automotive exterior sheet steel. In order to control these defects, various factors such as chemical composition, thermal equilibrium, and level management of galvanizing bath must be considered. This research relates to a process performed within a dam type snorkel included in the lower part of the snout facility, and this research improved an area where it was difficult for workers to monitor and control in real time and made the process smart. For this purpose, we’ll use camera and computing vision technology to analyze floating matter and flow rate of molten zinc on snorkel with optical technology to develop alarm system for operational risk, develop automatic control system linked to other facilities, and use it for process analysis. We’ll introduce the current status of technology development and additional process digitization plans using optical analysis technology of computing vision for the production of high-quality automotive exterior materials.

Enrique Frixione, OG Technologies, Inc., United States

Co-Author:
Chang Tzyy-Shuh, OG Technologies, Inc.
Michal Podermanski, Moravia Steel a.s

Abstract:
In 2018 and 2019, Třinecké Železárny implemented a project to replace the surface inspection equipment using eddy currents in the two-strand wire rod rolling mills. The imaging-based surface inspection system was selected for installation in the wire rod mill based on its proven defect detection capabilities in many SBQ wire mills. The first unit was installed in 2018, with a second installation to follow in 2019. The wire rod mill quality team at Třinecké Železárny found the range of quality data, including images of defects, to be beneficial. In addition to real-time detection and alarms resulting in mitigation of quality failures, the newly available surface quality data has led to the resolution of various surface quality issues and the development and implementation of a coil grading model based on customer requirements, wire diameter, material grades and surface quality data. The results of the quality scorecard, along with images of defects, are displayed on a large screen at the quality control station, providing all line operators across all mill shifts with a clear, consistent and repeatable assessment of the quality of each rolled coil. The introduction of imaging-based surface inspection systems, coupled with improvements to the rolling process that enable surface quality data, has contributed to the best quality performance in 2021 since the wire rod mill began operations in the mid-1970s. This document maps the processes, experiences and successes of surface quality improvement at the wire rod mills of Třinecké Železárny.

Alberto Nardini, POMINI Long Rolling Mills Srl, Italy

Co-Author:
Daniele Biagini, POMINI Long Rolling Mills S.r.l.

Abstract:
The uses of long quality products (SBQ) increasingly require high metallurgical properties and excellent tolerances. Rolling these products therefore entails a fast process that requires high speed control and communication capabilities, with fast response electromechanical-hydraulic control systems. To offer high process stability, POMINI Long Rolling Mills has developed a finishing-sizing unit equipped with an AGC (Automatic Gap Control) system for the automatic control of the gap between the rolls, able to dynamically maintain the required dimensional tolerances. The finishing-sizing unit is placed at the end of the continuous train and consists of two vertical and horizontal two-roll stands. To control the size of the bar, the AGC system manages the dynamic positioning of the rolls, whose light variation is applied by means of synchronous screws operated by a hydraulic servomotor with proportional valve. With the finishing-sizing unit enslaved to the AGC system, a minimum tolerance of 1/5 DIN for round bars can be obtained. The same system is applicable, with the applicable changes in the product characterization, even with flat bars, for which a minimum tolerance of 1/4 DIN can be obtained. This paper describes the main process and features of the system. KEYWORDS: HYDRAULIC POSITION CONTROL, AUTOMATIC GAP CONTROL, FINISHING SIZING STAND GROUP, AGC CONTROL

Pavel Vitoslavský, UVB TECHNIK s.r.o., Czech Republic

Abstract:
There are continuous contact and noncontact thickness gauges used in cold rolling process. The spectrum of noncontact measuring instruments has considerably expanded thanks to the development of new technologies and implementation of wide range of physical principles. The paper briefly reviews the types of noncontact measuring devices most frequently used today including laser thickness gauges. However environment including vapour, presence of oil or any liquid on the strip, chemical composition of the material, type of strip surface can be critical for noncontact measurement against the contact type. We will also mention an example of a unique application where contact thickness gauge is used for calibration of noncontact measuring gauge, e.g. for rolling aluminium or bimetal strips to provide safe, fast and accurate measurement. Consequently more detailed attention is given to the most important parameters and advantages of a contact thickness gauges that show us this measurement can still successfully compete with the noncontact measuring instruments and in some applications may even be the only one solution.

Nicole Voigt, Boston Consulting Group, Germany

Abstract:
Growing pressures from consumers and regulators, and as a result downstream producers, are driving a push to de-carbonize supply chains. Steel is often one of the largest emitters in supply chains. Stakeholders along the steel value chain have an opportunity to capture value by abating emissions and communicating lower than competitor emissions using Product Carbon Footprint (PCF), cradle to gate LCA. By using PCF to differentiate green goods, companies can drive P&L gains: 1) gain a price premium and 2) capture market share. PCF also drives second-order value: a) allows for portfolio optimization toward green products, b) facilitates supplier ecosystem management, c) provides continued access to sell into markets with increasingly restrictive regulatory and carbon pricing landscapes, d) improves trust in brand. This value from PCF is expected to be transient, reaching a maximum in the mid-term (2025-2035). To gain this value, businesses must begin measuring PCF in the near-term. Long-term, PCF will become commoditized and required for market participation. Calculating PCF can be challenging. Best practice is to leverage estimates where needed (BOMs preferred), to build capabilities and a leadership position. Initial PCF estimates will be based on emission factors, leveraging digital tools, such as CO2 AI, Ellipse, etc. Companies should try to progressively improve the quality of their estimates using direct measures and PCF of their inputs, shared by suppliers. Inter-company data sharing tools are required to achieve this, such as CO2 AI x CDP Product Ecosystem, Integrity Next, etc. Finally, gaining value requires PCF be high-quality, verifiable, and communicable. In this paper, we take a deep dive into how PCF drives value and explore best practices for calculating PCF using a case study. We describe challenges in deriving PCF for a complex steel value chain, considering technologies, and various forms of final product

Martin Theuringer, German Steel Federation, Germany

Abstract:
Green lead markets are a central policy component to flank the decarbonisation of the steel industry. The aim is to provide regulatory support for the demand side in order to relieve state start-up financing and replace it in the medium term. The problem, however, is that a definition of low-CO2 and near-zero steel in the long term is not yet available. Therefore, despite the Steel Action Plan and the National Hydrogen Strategy, no progress has been made on "green lead markets" in Germany (or in the EU). Internationally, the discussion is being conducted in a multitude of initiatives with high dynamics. There is a danger that regionally different standards will emerge with disadvantages for Germany / the EU as an industrial location. The proposal of the International Energy Agency within the framework of the G-7 is also a robust starting point from the point of view of the steel industry: However, further development is necessary.

Agnes Ritter, McKinsey & Company , Austria

Co-Author:
Marlene Weimer, McKinsey & Company, Inc.

Abstract:
Steel industry is under pressure as climate targets aim for net-zero GHG emissions by 2045 in EU. Doing so requires increasing annual investment into new technology and assets. Demand for low-CO2—or “green”—products is ramping up as end customers, manufacturers, and governments push for increased sustainability and circularity. Primary materials processing makes up the majority of GHG emissions for many industrial products, which has led to increased attention on decarbonizing core contributing commodities and will strengthen the need for recycling materials. In turn, time-bound green premiums are emerging for certain steel applications. This paper lays out the observed and potential supply–demand balances across four core commodities: Understanding where the extra cost for green steel can be captured will influence industry transition path and needed innovation. We assessed premiums for low-CO₂ materials premiums by modelling the expected demand, supply of green steel by technology, and green premiums required. McKinsey steel team – authors and presentation tbd BZ or Agnes

Saptarshi Bhattacharya, M. N. Dastur & Co., India

Co-Author:
Arnab Adak, M. N. Dastur & Co.
Atanu Mukherjee, Dastur Energy Inc.
Anindya Majumdar, M. N. Dastur & Co.
Arunava Maity, M. N. Dastur & Co.

Abstract:
While global CO2 emissions are set to reach around 40.5 GTPA by 2022, the steel industry alone contributes 7-10% of the total emission. The CO2-intensive BF-BOF route of steel production is pre-dominant and will continue for some time. Decarbonization of BF-BOF is limited by the economics of multi-point post-combustion capture and technology to replace coal. Dastur has designed a novel solution integrating gas conditioning unit, carbon capture unit, and combined heat and power (CHP) plant. Gas conditioning unit helps to increase CO2 concentration to >30% and to capture >85% of available CO2 from a single source, enabling carbon capture technology to work efficiently with the lowest $/Te. Additionally, H2 can be recovered from the H2-rich fuel gas stream at a marginal cost of <0.5 $/kgH2. Since CO2 concentration is >30%, a wide range of technologies (from steam-based amine to all-electric PSA/Cryogenic) can be deployed depending on CO2 purity requirement, net CO2 reduction target, electricity, and steam cost. Even steam and power sourcing options could differ depending on available waste recovery options in existing steel plant operations. Additionally, the deployment of carbon capture along with H2 recovery can enable a circular green economy through utilization of CO2 /H2 in downstream industries like aggregates, methanol based chemicals, Enhanced Oil Recovery, etc. The incentives and support from governments can accelerate decarbonization of steel further. This paper discusses the key design aspects, policy support and techno-economics of different options.

Michalis Agraniotis, Mitsubishi Heavy Industries EMEA Ltd., Germany

Co-Author:
Takashi Kamijo, Mitsubishi Heavy Industries Engineering, Ltd.

Abstract:
Decarbonization in Hard-to-abate industrial sector is considered as one of the key future challenges in Europe and worldwide towards reaching the targets of Paris Agreement. Electrification and use of hydrogen, are two emerging technologies which may become relevant for specific industrial applications. Nevertheless, carbon capture is already proven in the large industrial scale and is expected to play a key role in the decarbonization of these sectors through combination with permanent storage. MHI has more than 30 years’ experience in development and commercialization of its proprietary amine based carbon capture technology and has 14 industrial scale references, including the world’s largest post combustion CO2 capture project, Petra Nova. MHI has recently commercialized the “Advanced KM CDR ProcessTM”, which utilizes the new generation of its proprietary solvent KS-21TM. The new solvent has improved characteristics such as higher stability and lower volatility, and brings competitive advantages in terms of capex and opex for new carbon capture projects. In the present paper the experience from projects in Hard-to-abate sector like steel industry, is assessed. For the development of new large scale projects Feasibility and Pre-FEED study type of activities are combined together with specific test campaigns in dedicated mobile test units. In this way the impact of specific flue gas composition on the performance of the process and quality of captured CO2 from steel industry can be analyzed, so that the outcome can directly facilitate the design of the large scale project.

Kerstin Stenzel, thyssenkrupp Uhde GmbH, Germany

Co-Author:
Holger Thielert, thyssenkrupp Uhde GmbH
Dirk Scheckreiter, thyssenkrupp Uhde GmbH

Abstract:
The process of treating raw coke oven gas (COG) to generate a clean fuelgas is a well-known process nowadays and generates a number of valuable saleable side products. Simultaneously the combustion of clean COG causes CO2 emissions which will be more costly in future at most places. It is worth to think about other types of using COG which help to reduce the greenhouse gas emissions of the coke plant and even of the steel mill. By further upgrading COG can be applied for the production of chemicals or be used as reducing agent in the blast furnace as well as in the process for production of direct reduced iron. In addition to that the CO2 captured at the stack of a coke oven gas battery and the hydrogen extracted from the COG offer a promising opportunity for the production of a new range of chemicals improving the carbon footprint any further.

Sebastian Bock, Rouge H2 Engineering, Austria

Co-Author:
Gernot Voitic, Rouge H2 Engineering

Abstract:
RGH2’s novel chemical looping based system can directly convert CO, CO2 and N2 rich blast furnace gas (BFG), coke oven gas (COG) and basic oxygen furnace gas (BOFG) into high purity H2 with inherent CO2 capture. The produced hydrogen can be utilized to substitute coal in the blast furnace and decarbonize steel plants, or to decarbonize plant-integrated heat and power generation systems. Based upon results in RGH2’s 100 kW OSOD On-Site-On-Demand demo plant (TRL 6) [1], the process produces high-purity H2 (>99.99%) and pure N2 (98.5%) as products, while sequestrating a carbon dioxide rich stream without energy penalty [2, 3]. In the specific case of nitrogen-containing gases (BFG, COG, BOFG), RGH2’s 3-step system enriches the CO2 content up to 50%. Only a downstream separation of nitrogen is required for CO2 sequestration up to 99% capture rate. Thus, the whole system can be an important building block to decarbonize the integrated steel plants. [1] Voitic G, Legerer C, von Hofen F, Beese-Vasbender P. Deponiegas zur Wasserstoffproduktion nutzen. GWF Gas + Energie. Sep. 2022; 163(Sep). https://gwf-gas.de/aktuelle-ausgabe-9/ [2] Bock S, Zacharias R, Hacker V. Co-production of pure hydrogen, carbon dioxide and nitrogen in a 10 kW fixed-bed chemical looping system. Sustain. Energy Fuels Mar. 2020; 4(3):1417–26. https://doi.org/10.1039/C9SE00980A. [3] Bock S, Zacharias R, Hacker V. High purity hydrogen production with a 10 kWth RESC prototype system. Energy Convers. Manag. Sep. 2018; 172(May):418–27. https://doi.org/10.1016/j.enconman.2018.07.020.

Peter Glodek, GEA Bischoff GmbH, Germany

Co-Author:
Jens Lange, GEA Bischoff GmbH
Marcel Zillgitt, GEA Bischoff GmbH

Abstract:
With the goal of reducing greenhouse gases to prevent global warming above 2 °C, industry is facing an unprecedented challenge. In this context, the reduction of CO2, as the main driver of global warming, represents a sensible and sustainable solution from many points of view. On the one hand, there is increasing national and international pressure regarding energy and CO2 saving solutions. On the other hand, there is also an opportunity to reduce operating costs in long term by a new sustainable orientation. Particularly in the context of sharply rising certificate costs for CO2, a trend is emerging that a decisive step must be taken in the direction of sustainable and ecological industrial processes. The iron & steel industry is well aware of these issues; many plants have already taken the first step to energy and decarbonization optimization. A much-discussed approach is to substitute coke or natural gas with hydrogen, preferably produced climate-neutral, for the reduction of iron ore. Despite these process optimizations, the direct emission of CO2 should still be avoided. Chemical absorption by means of amine solution has become established as a commercially proven downstream solution. The absorption process requires a very low content of residual impurities in the off gas, which can be ensured by using advanced gas cleaning technologies. In addition to indirect CO2 reduction, direct heat recovery from the energy-rich process is particularly well suited here for solvent regeneration, whereby surpluses can still be used to cover the company's own electricity consumption and / or compressed air generation. In this context, an overview of the sustainability goals described above is given to focus on the expanded importance of emission control.

Yul Hong, Hyundai Steel Co., Korea, Republic of

Co-Author:
Yun Mo Lee, Hyundai Steel Co.
Byong Chul Kim, Hyundai Steel Co.

Abstract:
Suitable quality of sintered ore is a crucial factor for stable blast furnace process. However, it is difficult to predict various properties of sintered ore by identifying characteristics of blending ores such as ore size and chemical composition due to its complex reaction mechanism. Sintered ore is generated by assimilation process of granule particles composed of adhering fines and nuclei ores and its reactivity is changed by physical and chemical properties of iron ores. Especially, assimilation between coarse ores and fines is able to influence the sinter bonding strength. Therefore, this study aims to clarify influencing factors on assimilation process and identify correlation between sinter bonding strength and characteristics of coarse ore. To simulate sintering, pseudo particles were granulated with coarse ore (1-3 mm) and adhering fines which form primary melt and then sintered at 1623 K. The simplified Tumbler Index test (TI) was conducted to assess bonding strength of sintered ore particles. Iron ore Reactivity Indices (IRI) were obtained by evaluating TI values of 11 kinds of iron ore brands, respectively. As a result, physico-chemical properties of coarse ores such as gangue, LOI (Loss On Ignition) content and melting point influenced distinct assimilation properties. Coarse ore brand that undergoes intense assimilation reaction has higher IRI value and this phenomenon causes improving sinter bonding strength. Considering the association between Iron Blending ore Reactivity Index (IBRI) and quality of sintered ore generated in the sinter plant, we figured out that higher IBRI increases Shatter Index (SI) of sintered ore. This result shows that not only the comparison of the degree of iron ore assimilation reaction is able to rank each iron ore brands, but also it could predict quality of sintered ore dependent on IBRI.

Bárbara Dornelas, CRM Group, Belgium

Co-Author:
Clément Polato, ArcelorMittal R&D France
Maria Pacheco, Tata Steel Ltd
Laurent Fraiking, CRM Group
Clément Polato, ArcelorMittal R&D France
Maria Pacheco, Tata Steel Ltd
Laurent Fraiking, CRM Group

Abstract:
The dependency to raw materials costs makes the management of sintering plants an everyday challenge to reach the requested sinter quality and production rates while meeting all the environmental constrains (CO2 but also other pollutants like NOx and SOx). The increase of by-products recyclability and recycling rate shall improve both raw materials costs and environmental issues, improving competitiveness and sustainability of European steel industry with limited impact on process KPI’s. SinByOSe RFCS funded project focuses on selective preparation of by-products and solid fuels. The selective preparation of part of the sinter mix is a local countermeasure by means of chemical upgrading (removal of detrimental elements by pre-processing) and by means of particle shaping (pre-granulation). Main solutions investigated in the SinByOSe project consist in : • An innovative pre-processing to increase sinter dust recyclability doing a closed loop washing. The Chlorine abatement obtained is close to 91% and a high %KCl solution is generated, which could be valorized. • Selective pre-granulation of a selected part or whole of the by-products to be recycled through the sinter plant. Current results allows up to 16% productivity increase. • Solid fuel pre-granulation with lime, by intensive mixing, for process and environmental improvement. Results showed an increase of productivity up to 3 tsinter/m².d, a gain of solid fuel of 1 kg/tsinter and constant sinter quality. Environmental results showed a reduction by 15% of SO2 and dust emissions.

Mert Altay, Erdemir, Turkey

Co-Author:
Erdal Ünal, Erdemir
Selda Daldal, Erdemir
Kağan Keler, Erdemir

Abstract:
Iron ore sintering raw blends include various materials such as iron ore, coke, limestone, and recyclable ironmaking and steelmaking byproducts such as return sinter, slags, and sludges. One of these byproducts is basic oxygen furnace (BOF) slag which due to its high calcium and iron content regularly used in sintering by industry. As a recyclable material, it could partially substitute raw materials that include calcium and iron thus could provide sustainability and cost advantages to integrated steel plants. However, due to its impurity content, and physical and phase structure it could also deteriorate process efficiency or product properties. Thus, it is highly beneficial to define the effects of the BOF slag ratio in the raw blend on sintering parameters and sinter product. In this study, pilot scale sintering experiments were conducted with different BOF slag rates in raw blend changing from %0 to %9.25 and changes at the process parameters such as flame front speed, productivity and yield, and product properties such as tumbler index, shatter index and reduction disintegration index are investigated. The result showed that BOF slag usage could increase yield due to its lower loss on ignition compared to limestone however sintering time, productivity, and RDI could worsen with an increase in BOF slag usage rate.

Felix Firsbach, Badische Stahl-Engineering, Germany

Co-Author:
Andrea Pezza, Badische Stahl-Engineering
Per Lückhoff, Badische Stahl-Engineering
Peter van der Velden, Badische Stahl-Engineering
Patrick Hansert, Badische Stahl-Engineering

Abstract:
Decarbonization of iron- and steelmaking needs different approaches for different steel plants and aggregates. It can be categorized into three pillars: 1) process optimization, 2) adapting existing technology, and 3) investing in new technology. This paper addresses the implementation of new EAFs into existing melt shops with a focus on EAF design possibilities, their up- and downsides, and the challenges of switching from BOF to EAF operation.

Eros Faraci, Rina Consulting – Centro Sviluppo Materiali S.p.A, Italy

Abstract:
The steel production trough electric arc furnace (EAF) plays an increasingly important role in modern steelworks concepts. Today the electric arc furnace steel of the overall steel production in the EU-27 is just over 40 % (59 Mtons/year). The share of the global steel production by EAF route is expected to increase due to its more flexibility, less investment and lower environmental impact respects to the BF-BOF steel production route. Moreover, on the ongoing projects, related to green steel production by Direct Reduction, Integration (DRI) of renewable electricity and hydrogen production (as SALCOS and HYBRIT projects) will provide many opportunities to increase the EAF steel production route but in order to catch these opportunities a strategy for decarbonization and thus sustainability for EAF steel production must be implemented. In this frame the main objective of DevH2forEAF, project founded by RFCS, is to set up and test a EAF burner fed with hydrogen to replace natural gas. This project is coordinated by: RINA Consulting – Centro Sviluppo Materiali SPA (RINA-CSM) and the partners are: 1) Rheinisch-Westfaelische Technische Hochschule Aachen (RWTH); 2) Compania Espanola de Laminacion Sl (CELSA); 3) Ferriere Nord SPA (FeNo); 4) Nippon Gases Industrial SRL (NG Ind.) 5) SMS group SPA (SMS) 6) AFV Acciaierie Beltrame SPA (AFV Beltrame) This project provides a comprehensive analysis of H2 hydrogen burner in EAF through the main activities: 1) Design and realization of EAF burners, able to work with NG/H2 mixture, up to 100% hydrogen (SMS) 2) Design and realization of H2 pipeline from the tube trailer to EAF in safety conditions (NG Ind.) 3) Analysis the performance of hydrogen burner in replacement of NG through experimental trials at lab and pilot scale (RWTH and CSM) an at two industrial sites (FeNo and CELSA). The final results of this project will represent a milestone for the utilization of H2 in steelmaking and the first key step for the decarbonization of the steel industry.

Hannes Beile, tripleS GmbH & Co KG, Germany

Co-Author:
Michael Hötzel, SHS - Stahl-Holding-Saar GmbH&Co.KGaA
Dirk Deckers, SHS - Stahl-Holding-Saar GmbH&Co.KGaA
Dominik Schöne, SHS - Stahl-Holding-Saar GmbH&Co.KGaA
Andreas Schneider, SHS - Stahl-Holding-Saar GmbH&Co.KGaA
Markus Abel, tripleS GmbH & Co. KG

Abstract:
A comprehensive process transformation from a conventional integrated steel plant with blast furnace and converter into a modern electric steel plant with the aim of drastically reducing CO2 emissions is technically not easy and requires a careful consideration of all possible solutions. In particular, the effects on both - productivity and the quality of steel grades to be produced should not be underestimated or neglected. This article describes one of several possible solutions for the transformation of integrated steel plants: The implementation of an electric arc furnace - possibly together with a new reduction reactor to use direct reduced iron. Various considerations and challenges are identified in this paper, such as: Maintaining the original tapping weight or working with a different tap weight (partial tapping), is the necessary electrical connection capacity available or the given network stability sufficient and what solutions are available if not, is enough space available in a steel plant that has grown over decades for an integration of a new melting unit with reduction reactor, how will the raw material situation look like in 10 or 20 years? What is possible with an electric arc furnace? Is it realistic to produce actual steel grade qualities using an EAF as melting unit - and if yes - with how much virgin material? Does the possible or needed raw material scenario change the overall productivity? Can existing equipment in secondary metallurgy be reused or is there additional investment needed as well? All these questions and challenges will be explained and described in this article based on existing reference examples in cooperation with Stahl-Holding Saar for the locations in Dillingen and Völklingen.

Maximilian Nagel, thyssenkrupp Hohenlimburg GmbH, Germany

Co-Author:
André Matusczyk, thyssenkrupp Hohenlimburg GmbH
Henrike Bröker, thyssenkrupp Hohenlimburg GmbH
Andreas Tomitz, thyssenkrupp Hohenlimburg GmbH
Max Müntefering, thyssenkrupp Hohenlimburg GmbH
Gerhard Gevelmann, thyssenkrupp Hohenlimburg GmbH
Marisa Taube-Levermann, thyssenkrupp Hohenlimburg GmbH
Stephan Kovacs, thyssenkrupp Hohenlimburg GmbH

Abstract:
Modern applications demand high formability due to increased complexity in part designs. Conventional microalloyed steels are often limited in this respect. The new High Ductility (HD) grades solve that issue. In yield strength ranges from 315 up to 700 MPa, their outstanding local forming reserves enable a reliable production process even for components that require complex forming operations. Especially in the automotive industry easy to weld materials for lightweight applications – with higher strength levels and lower sheet thicknesses – have become more and more important in the recent years. The HD grades fulfill all normative requirements of the EN 10149 and VDA 239-100 respectively and can be used to easily replace conventional HSLA steels. Beneficial for the medium strength grades is also their higher value in scrap commercialization due to specifically designed chemical compositions. All available hot-strip HD grades are fully characterized regarding their local formability, hole expansion ratio, bending radii and welding behavior. Narrow scatter bands in material properties allow a smooth production. With their quasi-single-phase ferritic matrix, they are already applied in automotive safety components and modern axle designs within electric vehicles.

Franz He, Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany

Co-Author:
Marion Merklein, Fraunhofer Institute for Manufacturing Technology and Advanced Materials

Abstract:
Energy conservation and overall vehicle efficiency has been steadily gaining importance in the automotive sector over the years, especially with the technological switch to electrically powered vehicles. Lightweight parts are therefore required to provide safety relevant components with reduced part weight for the automobile while at the same time not compromising in aspects of passenger security. Hot stamping has proven itself to be a suitable process for the generation of automotive components, which meet the contrary requirements by improving mechanical properties and thereby passenger safety while at the same time providing lowered part weight through reduced sheet thickness. Due to increased forming temperatures above 850 °C, the usage of lubricants is not yet viable for hot stamping. To prevent decarburization and scale formation an additional aluminium-silicon based coating is applied to the boron manganese base material. The lack of lubricant usage combined with the coating material results in occurrences of high friction and wear at high temperatures. Previous investigations have shown that process parameters exhibit a significant influence on friction and wear in the process. Furthermore, the workpiece sided austenitization parameters as well as coating thickness have proven to influence the layer formation in the coating layer. Within this study the influence of the initial coating thickness on the friction and wear behaviour as well as interdependencies with other significant parameters is investigated. To this end, strip drawing tests are performed with both coating strengths and analysed in regard to the resulting tribological behaviour. The results of this study help in improving the understanding of the tribological conditions within the hot stamping process and to develop tailored measures for reducing tool and part wear.

Alexander Gramlich, RWTH Aachen University, Germany

Co-Author:
Ulrich Krupp, RWTH Aachen University
Frederike Brasche, RWTH Aachen University

Abstract:
Press hardening of manganese-boron steels is one of the most efficient production processes for high strength automotive sheet components. However, the energy absorption capacity of these components is greatly limited by the formation of fully martensitic microstructure during in-die quenching. In order to extend the application range of press hardened components, the use of third-generation advanced high strength steels, especially medium manganese steels, achieves increasing attention. The alloying concept of these steels allows the critical cooling rate and the Ac3-temperature to be significantly lowered compared to manganese-boron steels, resulting in a lower austenitizing temperature and shorter cycle times. Aim of the presented research is to analyze the potential of press hardening of lean medium manganese steels with an integrated intercritical annealing or quenching & partitioning treatment. Therefore, different heat treatments were performed on Fe-0.3%C-5%Mn-1.5%Si and Fe-0.2%C-7%Mn-0.2%Si. By adjusting the heat treatment parameters, the microstructure and hence the mechanical properties can be modified to fit the application´s load requirements. The results demonstrate that both treatment strategies lead to complex multi-phase microstructures, which have been analyzed in detail by a combination of EBSD and EPMA. Optimization in heat treatment results not only in high tensile strength, comparable to martensitic 22MnB5, but also in significantly improved total elongation. Regarding the ductility, it was shown that besides the adjustment of a sufficient retained austenite content, the reduction of fresh martensite is indispensable to prevent brittle failure. Finally, selected heat treatments were reproduced in a laboratory-scale press hardening with temperature-controlled hat-shaped pressing tool.

Rico Haase, Fraunhofer Institute for Machine Tools and Forming Technology, Germany

Co-Author:
Matthias Nestler, Fraunhofer Institute for Machine Tools and Forming Technology
Julia Schönherr, Fraunhofer Institute for Machine Tools and Forming Technology
Verena Kräusel, Fraunhofer Institute for Machine Tools and Forming Technology

Abstract:
By press hardening of boron-manganese-alloyed steels, extraordinary strength can be achieved. Accordingly, the process is applied for different crash relevant components in the car body structure. Aiming for an outstanding energy dissipation, sections with lower ultimate strength to the benefit of an increased elongation are required. This can be achieved by a tailored tempering process, where the uniform heating and segmented cooling figured out to be the most appropriate process route on an industrial scale. Due to the non-uniform distribution of temperature during the quenching phase and the uneven level of thermal strains in the final cooling subsequent to the forming itself, a higher level of distortion was observed. Thus, a detailed understanding of the thermal effects and flux during the whole process chain is a key condition in order to achieve stable mechanical as well as geometrical properties. Within the recent research project gratefully supported by FOSTA, this detailed analysis of the thermal evolution of the different part sections of a tailor-tempered part were elaborated. By the repetitive crosscheck between process-integrated measurement and FEA prediction, the microstructural evolution and geometric accuracy were investigated. The relation between elastic spring back, thermal shrinkage and their interaction towards parts stress state and geometric deflection was examined. By the more detailed understanding of the underlying mechanisms, the route is opened for well-aimed compensation strategies. While the portion of press-hardened and in particular tailor-tempered components is established and stable in the car body structure, the ongoing development towards large-sized BIW-components such as the door ring concept come into the competition. This amplifies the relevance of the component accuracy and thus of the presented topic.

Ondrej Baco, Thermo Fisher Scientific Inc., Czech Republic

Co-Author:
Roger Maddalena, Thermo Fisher Scientific Inc.

Abstract:
At the end of the hot rolling process, microalloyed steel will form nanoscale precipitates of compounds such as NbC and TiN. These precipitates have the potential to improve properties by grain refinement and precipitation hardening. Precipitates with smaller size and higher number density typically yield higher strength. The rate of cooling after hot rolling will control the precipitation and coarsening of these particles. One of the challenges is to obtain a statistically meaningful distribution of their size, shape and composition as up to now this has only been possible with tedious, manual analysis. In this study an electron microscopy workflow is presented where the acquisition of images and chemical information is fully automated, even for overnight analysis on large area samples. The automated TEM allowed processing and comparing a statistically relevant number of particles (thousands) of steel lamellae samples from the coil head and coil middle. With these workflows, the time to improve processes and to develop a new steel product can be reduced and R&D manpower can be freed up for new responsibilities.

Seiji Morishige, KOBE STEEL, LTD. , Japan

Abstract:
In the Advanced and Ultra High-Strength Steel (AHSS, UHSS) strip annealing line, press flaws, called “Pick-up”, generated on the strip surface are sometimes caused by hard deposits on the surface of the furnace roll. If “Pick-up” occurs, strip line operation is interrupted for maintenance and an exchange of rolls. The investigation of the “Pick-up” mechanism and its suppression have been invented by using an experimental method in which the reaction of the steel surface-layered powder and the thermal spray layer were considered. However, in this experimental method, the contact state between rolls and steel strip was not reproduced. In the actual conditions, we assume that sliding contact is an important factor in the initial adhesion of pickup. We developed a simulator in which the contact state in the annealing line could be reproduced. The simulator has a mechanism to rotate rolls, while pressing the roll against the steel, and slide horizontally at the same time. In this simulator, a new surface of the strip and rolls can be in contact continuously while reproducing the sliding contact. The atmosphere and temperature of the simulator can be reproduced under the conditions of the actual equipment. The contact pressure between the roll and the steel can be controlled based on the load cell measurement. The test results from the simulator, showed that it was possible to reproduce the same adhesion form as the furnace roll deposit. In addition, it was confirmed that the time to initial adhesion differs depending on the steel grade and the conditions under which the film is changed. By using this simulator, we were able to select the optimum thermal spray layer and introduce it into the actual equipment, achieving an extension of the roll life by avoiding “Pick-ups”.

Nicolae Serban, University Politehnica of Bucharest, Romania

Co-Author:
Mariana Lucia Angelescu, University Politehnica of Bucharest
Vasile Dănuţ Cojocaru, University Politehnica of Bucharest
Elisabeta Mirela Cojocaru, University Politehnica of Bucharest
Irina Varvara Balkan, University Politehnica of Bucharest
Dana Mariana Serban, University Politehnica of Bucharest
Ovidiu Tanase, TURBOMECANICA S.A.
Robert Craciun, TURBOMECANICA S.A.

Abstract:
Shot peening is a very efficient treatment in order to increase fatigue resistance and prolong the life of metal components, while reducing tensile stresses induced by machining and heat treatment processes. The objective of the experimental research presented in the paper is to optimize the technology of mechanical treatment through shot-peening of aircraft parts made of 9310 VAR steel, in order to improve the efficiency of the process and obtain products of increased quality. The influence of the following industrial treatment parameters on the microstructural and mechanical characteristics of the samples was studied: the size of the shot balls, the working pressure and the exposure time. Steel metal balls with different diameters were used: d1 = 0.3 mm (ASR 110, 45-52 HRC) and d2 = 0.6 mm (ASR 230, 45-52 HRC). Also, two values were used for the working pressure (compressed air pressure): p1 = 3 bar and p2 = 5 bar. The exposure time of the samples to the shot-peening treatment varied between 5 - 35 minutes, as follows: t1 = 5 min, t2 = 15 min, t3 = 25 min and t4 = 35 min. The samples resulting from the laboratory experimentation of the designed technology were subjected to an advanced structural and mechanical characterization through XRD analysis, optical microscopy, SEM electron microscopy, microhardness tests and static tensile tests. The tensile strength (σUTS), the yield strength (σ0.2) and the elongation at break (εf) were measured. The results are interpreted and will be used for the fine adjustment of the working parameters and finally for establishing the optimal technological variant of mechanical surface treatment by shot-peening.

Kai K. O. Bär, adphos Innovative Technologies GmbH, Germany

Abstract:
Today mostly thermal metal and especially most surface processes are based on fossil heating systems, whether oil or gas fired. These convection heat transfer driven ovens and driers, build very large, provide limited energy efficiency, little size/width power adjustment and show low dynamic power control characteristics. In addition, a systems inherent CO2-emission footprint of 200 – 300 g per thermal kWh heating energy is generated. The proprietary fully electro-thermal aLITE – (advanced Light Initiated Thermal Emission) Technology, a proprietary high power photonic heating and drying system enables now alternative solutions for a wide range of heating processes (e.g. defined heating, even locally focused up to 1,500 °C, air, special atmosphere, vacuum) and various drying and curing applications (e.g. rinse water, water-based coatings, water/solvent even powder based paints and coatings). The aLITE-processing allows instantaneous on/off and fully defined processes. Dynamic adjustable to mass, size and geometry changes. No need for pre-heating or standby operation. The extreme compact and energy efficient systems operation justifies attractive upgrade/replacement projects. Based on an introduction of the work principle of the aLITE-technology, already realized examples in commercial metal processing lines (e.g. pickling, hot roll, annealing, coil coating) are shown and competitive evaluated with traditional solutions.

Stephan Schirdewahn, Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany

Co-Author:
Niels Carstensen, Federal Institute of Materials Research and Testing
Kai Hilgenberg, Federal Institute of Materials Research and Testing
Marion Merklein, Fraunhofer Institute for Manufacturing Technology and Advanced Materials

Abstract:
Hot stamping has been established in the automotive industry as a key technology for lightweight construction, regarding the manufacturing of safety-relevant car body components. Hot stamped parts are commonly made out of boron-manganese steel sheets 22MnB5, which are initially austenized and subsequently formed and quenched simultaneously. However, these cyclic thermo-mechanical loads encourage the formation of severe wear and high friction at the blank-die interface, which in turn leads to a time and cost consuming rework of the tool. For this purpose, a promising new approach named laser implantation process has been investigated for improving the tribological behavior of hot stamping tools. This technique enables the generation of highly wear resistant, separated and elevated features in micrometre range by embedding hard ceramic particles into the tool surface via pulsed laser radiation. As a result, the contact area between tool and surface and thus the tribological and thermal interactions are locally influenced. Within first studies, the effectiveness of the laser implantation process has already been proven in laboratory scale by means of modified pin-on-disk tests. However, the transferability of this surface engineering technology with regard to an industry-related deep drawing process has not been investigated in detail yet. For this purpose, a locally modified as well as a conventional die are utilized for hot stamping rectangular cups, in order to qualify the tribological impact of the laser implantation process by using an industry-related tooling system. To evaluate the tribological performance, the maximum punch forces of both tool configurations were compared in order to draw conclusions about the frictional behavior during the forming operation. In addition, hardness measurements were carried out as well as the resulting part geometry was scanned by means of the topometric 3D-sensor ATOS for analysing the mechanical properties and sheet thickness distribution of the hot stamped cups.

Mario Gelmini, BM GROUP POLYTEC S.p.A., Italy

Co-Author:
Ion Rusu, BM GROUP POLYTEC S.p.A.
Tiziano Bagozzi, BM GROUP POLYTEC S.p.A.

Abstract:
The developed robotic system allows to easily reach the best pick-up point, depending on the plant layout. The cut can be carried out using different techniques, based on the type of material, the cutting quality required or based on the target performance (Circular or band saw, Shear, oxyacetylene cutting torch, Laser) The vision system that performs 2D / 3D scanning, identifies the arrival position of the material to be cut and can integrate a partial control of the sample in terms of size. The option of the robot mounted on an autonomous vehicle allows the automated handling when samples need to be taken from different points of the plate or from different plates and the automated samples’ handling to the lab station.

Ondřej Vitoslavský, UVB TECHNIK s.r.o., Czech Republic

Abstract:
Degreasing equipment is aimed at manufacturers and processors of metal strips. It is designed for removing rest of oils and emulsions off the strips on processing lines, to clean and dry the strip surface. The Degreasing Equipment consists of 3 sections: 1. Wetting section with pressure nozzles (for bottom and upper strip surface). 2. Brushing section with two round brushes rotating against strip movement. 3. Wiping section with 2 pairs of specially shaped plastic wiping slats. In order to remove impurities, the unit is fitted with pressure blasting jets driving the impurities to the sides of the strip. Wiped oil and emulsions with the degreasing liquid are collected through a bath to a tank for waste sludge.

Eric Almquist, Chicago Heights Star Tool & Die Works, Inc., United States

Abstract:
Reliable, continuous, non-contact, online monitoring of metal’s surface cleanliness is a reality after years of challenges with laser reliability within finishing lines. Premium sheet finishing lines (e.g., CGL, CAL/CAPL, tinning) typically utilize cleaning sections to remove surface contamination early in their process to optimize finished product quality and operational reliability. Until today there hasn't been a practical method to continuously monitor surface contamination. Oftentimes, cleaning sections are complex, multi-stage systems with significant operating costs with little, to no, ability to verify results until a problem appears because of insufficient cleaning. This leads to operation mentalities of wastefully operating all cleaning systems ‘flat-out’ no matter the cost or because of some other ‘process control plan’ based of legacy experience, intuition from archaic wipe tests, arbitrary hunches, or even running a ‘trouble-shooting’ scheme of ‘changing-this and adjusting-that’ until some level of satisfactory outcome is attained after generating tons of scrap. The TST.1 systems utilize the elegantly simple technique of laser ablation (LA) to provide real-time evaluation of surface contamination levels along the entire length of the coil, generating high-resolution data as frequent as 10 Hz. Operators can visualize cleanliness trends before they become a problem and even ‘throttle’ the cleaning section to clean the surface ‘sufficiently’ versus running flat-out. The system has ability to display fine changes: differences in electrolytic cleaner phase, individual brush performance, changes in spray sections, etc. Realtime cleaning section optimization is now possible. This practical presentation will provide details of the TST.1 systems being used within customers’ operations including actual results from interesting cases. Other details: fundamentals of why cleanliness is important; various cleanliness tests used over the decades; the difficult path of getting lasers to survive in process lines; along with other technical details of the system.

Patrick Siemann, SMS group, Germany

Co-Author:
Mark Zipf, SMS group, Inc.

Abstract:
High-fidelity flatness defects can plague the surface appearance / aesthetics of cold rolled finished strip, when directly shipped, without further processing (e.g., tension leveling) or inspection. Here, during on-line rolling activities, the high speeds and strip tensions may obscure the visually assessed presence of these defects, leading mill operators to wrongly conclude a defect-free delivered strip, that is ready for direct shipment. It’s not uncommon for the defect pattern’s elements to have longitudinal and transverse dimensions that resides near (or beyond) the spatial sampling capabilities of the typical shapemeter rolls sensing array (leading to aliasing). The shapemeter roll’s “effective” spatial sampling frequency may be degraded by temporal or smoothing filtration within the shape measurement’s signal conditioning. In many respects, one could argue (correctly) that this class of flatness defect will be strongly under-sampled. The defect elements are too fine to be reliably captured by currently available shape measurement systems, leaving no realistic opportunity to correct (in real-time, while rolling) with closed-loop shape controls. While this may be the case, there may be weak, “ghostly”, under-sampled remnants of the defect pattern, hidden within high frequency logs of the shapemeter’s raw (but calibrated) radial force measurements. Being able to detect the presence of these unobservable defects (from the hidden remnants) may offer quality control personnel new opportunities to make post-rolling assessments of the coil’s integrity and acceptability for direct shipment (without off-line inspection). This paper will examine the use of under-sampling reconstruction methods coupled with weak signal extraction / enhancement techniques, to render visually apparent images indicating the presence of this type of defect. This paper will also discuss how pattern recognition strategies can offer the ability to automatically detect these defects, with possible implications for use in on-line / real-time scenarios.

Alessandro Stenico, PSI Metals GmbH, Germany

Co-Author:
Akriti Malla, PSI Metals GmbH
Robert Jäger, PSI Metals GmbH

Abstract:
At the age of Industry 4.0 and complex supply chain ecosystems, production management systems face a double challenge: first, they need to be re-designed to address increasing requirements for supply chain flexibility and resilience: business process flows and manufacturing strategies need to be more adaptive than ever, and this translates to the production management system. Second, they must incorporate technological developments that came along with the fourth industrial revolution, including dedicated industrial artificial intelligence (AI) and data science services, in order to leverage the added value lying in Big Data and support digitally driven manufacturing processes. In Quality Control, for instance, the aim of zero defects and no downgrades can be approached by enhanced process and product insight paired with the capability of fast, smart, and sustainable reactions, including online prediction and prescription, transparently executed. In Production Planning, work-in-progress (WIP) material residence times in stockyards and manufacturing lead times could be predicted by dedicated machine learning services, while smart autonomous agents could automatically adjust planned production schedules based on such results. Yet, to support such capabilities, production management systems must allow metals producers to model their business processes in workflows and integrate plug-and-play services. They demand collaboration between independent solutions, real-time visibility through embedded analytics, business logic configurability and the possibility of scope extensions via low-code approach. All of this needs to be supported by automated deployments, regardless if on-premise or in the cloud, and seamless upgrades ensuring minimal downtime during upgrade processes. Last but not least, they must provide state-of-art encryption mechanisms and resilience to cybersecurity threats. This paper explores the IT infrastructure and business process management functions that a metals production management system 4.0 must provide, to plainly support and leverage the promises of the industrial internet revolution.

Falk-Florian Henrich, Smart Steel Technologies GmbH, Germany

Co-Author:
Lucas Corts, Smart Steel Technologies GmbH

Abstract:
Conventional scheduling methods utilized in the steel production process, primarily semi-manual in their nature, tend to result in operational challenges. They are characterized by a lack of accurate and reliable quality prediction capabilities and cannot cope with the complexity of dynamic synchronization of upstream and downstream operations. An insufficient level of automation and a limited planning horizon present challenges in effectively harmonizing the planning of melt shop, casting and rolling operations. As a result, the direct and hot charging rates of an integrated steel plant are often low, leading to suboptimal energy utilization and high inventory and slab handling costs. To overcome these challenges, advanced scheduling systems that employ a combination of automation and reliable quality prediction have been developed. These systems can adjust dynamically in real-time to mitigate upstream deviations, which leads to increased hot charging rates and improved energy efficiency. By using automated scheduling, high utilization and coordination of equipment across all process stages can be accomplished. Smart Steel Technologies will elaborate on how an advanced scheduler utilizes mixed integer solvers and artificial intelligence models to optimize the scheduling process. Intelligent cost functions take into account quality predictions and all influencing restrictions from relevant aggregates. As a result, precise scheduling that boosts productivity and lowers energy consumption in difficult market conditions can be achieved.

Heinz-Josef Ponten, PSI Metals GmbH, Germany

Co-Author:
Rudolf Felix, PSI Fuzzy Logik & Neuro Systeme GmbH
Sebastian Grob, PSI Metals GmbH

Abstract:
There is no doubt that high-quality steel is indispensable in today's industrialized society, and steel producers have always been confronted with the dilemma of meeting the market requirements for new and thus more complex steel grades in an economically attractive way. A further dimension, the obligation of the steel industry to transform to carbon-neutral and more energy-efficient production, is added, which is becoming a tightrope walk due to the current situation on the energy markets. So how can steel producers optimize production processes, manage their heat schedules, save energy, comply with CO2 regulations and stay competitive with changing market demands? This paper discusses how collaborative smart software helps to optimize energy usage and hence influences CO2 reduction targets while minimizing production and material costs. An Online Heat Scheduler creates a detailed work schedule for all planned heats, including all required treatment and transport steps, their durations, the assignment of required production facilities and operating equipment as well as forecasts for required energy and material demands. Furthermore, it secures the required throughput and eliminates unpredicted discontinuity or sequence interruption at the caster line in case of unplanned standstills or delays. This process ensures efficient process quality by means of intelligent data collection, analysis and balance between target and criteria conflicts. Our approach is a proven industry standard, which helps plant managers flexibly manage planned downtime/maintenance work, plant problems, Hot Metal, DRI or Oxygen availability, Electrical Energy demand forecast and usage which leads to significant reduction in energy consumption and costs. Keywords: Decarbonization; Energy; CO2-Emission; Forecast; Qualicision; Heat Scheduling; Shopfloor

Jens Brandenburger, VDEh-Betriebsforschungsinstitut GmbH, Germany

Co-Author:
Miguel Gutierrez, Universidad Politécnica de Madrid
Joaquin Ordieres, Universidad Politécnica de Madrid
Alessandro Maddaloni, Institut Polytechnique de Paris
Valentina Colla, Scuola superiore di studi universitari e di perfezionamento Sant'Anna
Vincenzo Iannino, Scuola superiore di studi universitari e di perfezionamento Sant'Anna
Christoph Schirm, Thyssenkrupp Rasselstein GmbH
Dirk Müller, Thyssenkrupp Rasselstein GmbH
Erwin Sirovnik, Thyssenkrupp Rasselstein GmbH
Andreas Wolff, VDEh-Betriebsforschungsinstitut GmbH
Ahmad Rajabi, VDEh-Betriebsforschungsinstitut GmbH

Abstract:
Within the RFCS project DynReAct new concepts to improve the flexibility of production scheduling in flat steel production were developed and demonstrated at the tin-plate production site of thyssenkrupp Rasselstein in Andernach providing multiple production steps with free choice of multiple plants for production of a certain product. The selected concept follows a hybrid scheduling approach combining three planning levels with different planning horizons as well as planning accuracies to provide robust production plans on the one hand and flexible reaction strategies in case of unexpected events or decreasing plant performances on the other hand.

Marc Schwarzer, PSI Metals GmbH, Germany

Abstract:
Metals producers with complex routings (e.g. various finishing options, alternative “sister” shops) require reactive Planning and flexible Material Allocation. Dynamic Order Dressing (OD) provides several advanced features, which combined into the proper overall system architecture, can provide the vital inputs for an optimized Planning decision. Initially a Sales Order Item Position is elaborated into multiple alternative Production Order (PO) variants, each of which is representing an individual unique routing. Within each PO variant OD is calculating multiple Material Demand Variants (modelling alternative dimensions and cutting factors) that can lead to additional PO variants. Traditionally, PO Variants had to be pre-determined on Sales Order pre-processing level, e.g. using high level rules that suggest using three PO Variants to model different plant routings. With Dynamic Order Dressing PO Variants can now be determined dynamically during the Material Demand calculation. For instance, the routing determination returns multiple alternatives at certain decision points and after you determined the exact intermediate and final materials, you can dynamically generate additional auxiliary PO’s (first calculate the exact Pipe dimensions and pieces and afterwards generate an according Coupling PO). Finally Due Date Quoting (DDQ) will evaluate all PO Variants and according to configuration determine their potential due date and select the best PO Variant according to optimization criteria. At later time Material Allocation is executed, preferably using the primary Material Demand Variant of the PO Variant selected by DDQ. The additional Variants, however, extend the room for solutions significantly, reducing unassigned stocks for the plant. This comes especially handy when a plant purchases many intermediate materials of different dimensions externally. Once such alternative intermediate material design is selected for allocation, this will automatically trigger a Material PO generated by Forward Dressing to ensure optimal routing, production and quality instructions for this non-standard material.

Fuqiang Wei, Shougang Group Company, China

Co-Author:
Jian Zhang, Shougang Group
Jiangtao Zheng, Shougang Group
Xiangjun Meng, Shougang Group
Chao Wang, Shougang Group
Jiangli Yang, Shougang Group

Abstract:
Abstract：This paper summarizes the change of steel coil transportation technology in strip mill plant in recent 20 years, analyzes the traditional steel coil transportation modes and their technical characteristics, introduces the new intelligent vehicle powered by super capacitor, compares this new type vehicle with the traditional technology, and briefly describes the engineering case and practical application of the new technology, It is concluded that rail transportation and intelligent are the development trends of steel coil transportation in steel plant.

Elyas Ghafoori, Leibniz University of Hannover, Germany

Co-Author:
H. Dahaghin, University of Tehran
C. Diao, Cranfield University
N. Pichler, Empa, Swiss Federal Laboratories for Materials Science and Technology
L. Li, Empa, Swiss Federal Laboratories for Materials Science and Technology
M. Mohri, Empa, Swiss Federal Laboratories for Materials Science and Technology
J. Ding, Cranfield University
S. Ganguly, Cranfield University
S. Williams, Cranfield University

Abstract:
In this study, a directed energy deposition (DED) process called wire arc additive manufacturing (WAAM) is employed for the fatigue strengthening of damaged steel members. Three steel specimens with central cracks were tested under a high-cycle fatigue loading (HCF) regime: (1) the reference specimen; (2) the WAAM-repaired specimen with an as-deposited profile, and (3) the WAAM-repaired specimen machined to reduce stress concentration factors (SCF). The corresponding finite element (FE) simulation of the WAAM process was calibrated using static experimental results, which revealed the main mechanism. The process was found to introduce compressive residual stresses at the crack tip owing to the thermal contraction of the repair. The FE results also revealed that stress concentration exists at the root of the as-deposited WAAM; this stress concentration can be mitigated by machining the WAAM to a pyramid-like shape. The fractography analysis indicated that the cracks were initiated at the WAAM-steel interface, and microscopic observations revealed that the microcracks were arrested by the porosities in the melted interface. The results of this pioneering study suggest that WAAM repair is a promising technique for combating fatigue damage in steel structures.

Karsten Wandtke, Federal Institute of Materials Research and Testing, Germany

Co-Author:
Dirk Schroepfer, Federal Institute of Materials Research and Testing
Ronny Scharf-Wildenhain, University of Technology Chemnitz
André Haelsig, University of Technology Chemnitz
Arne Kromm, Federal Institute of Materials Research and Testing
Thomas Kannengiesser, Federal Institute of Materials Research and Testing
Jonas Hensel, University of Technology Chemnitz

Abstract:
High-strength steels offer great potential in weight-optimised modern steel structures. Additive manufacturing processes, such as Wire Arc Additive Manufacturing (WAAM), enable near-net-shape manufacturing of complex structures and more efficient manufacturing, offering significant savings in costs, time, and resources. Suitable filler materials for WAAM are already commercially available. However, the lack of knowledge or technical guidelines regarding welding residual stresses during manufacturing and operation in connection with cold cracking risk limit their industrial application significantly. In a project of BAM and TU Chemnitz, the influences and complex interactions of material, manufacturing process, design and processing steps on residual stress evolution are investigated. By developing process recommendations and a special cold cracking test, economic manufacturing, and stress-appropriate design of high-strength steel WAAM components are main objectives. The present study focuses on determining the influence of heat control (interpass temperature, heat input, cooling time) and the design aspects of the components on the hardness and residual stresses, which are analysed by X-ray diffraction. Defined reference specimens, i.e., hollow cuboids, are automatically welded with a special WAAM solid wire. The influences of wall length, wall thickness and wall height on the residual stresses are analysed. Geometric properties can be selectively adjusted by wire feed and welding speed but cannot be varied arbitrarily. This was addressed by adapted build-up strategies. The results indicate a significant influence of the heat control and the wall height on the residual stresses. The interpass temperature, wall thickness and wall length are not significant. These analyses allow recommendations for standards and manufacturing guidelines, enabling a safe and economic manufacturing of high-strength steel components.

Elyas Ghafoori, Leibniz University of Hannover, Germany

Co-Author:
N. Pichler, Empa, Swiss Federal Laboratories for Materials Science and Technology
L. Li, Empa, Swiss Federal Laboratories for Materials Science and Technology
C. Huang, Imperial College London
D. Ferrari, Empa, Swiss Federal Laboratories for Materials Science and Technology
E. Chatzi, ETH Zurich
L. Gardner, Imperial College London

Abstract:
Wire arc additive manufacturing (WAAM) is a metal 3D printing technique that is well recognised in the construction sector for its high efficiency, cost-effectiveness and flexibility in build scales. However, there remains a lack of fundamental data on the structural performance of WAAM elements, especially regarding their fatigue behaviour. A comprehensive experimental study into the fatigue behaviour of WAAM steel plates has therefore been undertaken and is reported herein. Following geometric, mechanical and microstructural characterisation, a series of WAAM coupons was tested under uniaxial high-cycle fatigue loading. A total of 75 fatigue tests on both as-built and machined coupons, covering various stress ranges and mean stress levels, have been conducted. The local stress concentrations in the as-built coupons, induced by their surface undulations, have also been studied by numerical simulations. The obtained fatigue test results were analysed using constant life diagrams (CLDs) and S-N (stress-life) diagrams, based on both nominal and local stresses. The CLDs revealed that the fatigue strength of the as-built WAAM steel was relatively insensitive to the different mean stress levels. The S-N diagrams showed that the surface undulations resulted in a reduction of about 35% in the fatigue endurance limit for the as-built material, relative to the machined material, and a reduction of about 60% in the fatigue life for a given stress level. The as-built and machined WAAM coupons were shown to exhibit similar fatigue behaviour to conventional steel butt welds and structural steel S355, respectively. Preliminary local stress-based and nominal stress-based S-N curves are also proposed for the WAAM steel.

Ronny Kühne, RWTH Aachen University, Germany

Co-Author:
Helen Bartsch, RWTH Aachen University
Markus Feldmann, RWTH Aachen University

Abstract:
Scope of this research is the fatigue resistance of additively manufactured steel plates with galvanized surfaces. First the manufacturing process via wire arc additive manufacturing (WAAM) and hot dip galvanizing (HDG) of the specimens is described. In order to determine the influence of HDG on the fatigue resistance next to fatigue tests itself investigations on the surface roughness, the condition of the zinc layer and quasi-static tension on galvanized and ungalvanized specimens are pointed out. Even though, statistically no influence of the zinc coating on the surface roughness has been obtained, the zinc coating influences the surface shape in local areas leading to a reduction in the fatigue resistance due to the unidirectional dentritic growth of the Zn-Fe phase.

Yu-Chiao Lu, KTH Royal Institute of Technology, Sweden

Co-Author:
Christopher Hulme, KTH Royal Institute of Technology
Leyla Koort, KTH Royal Institute of Technology
Viktoria Sutorius Trollbäck, KTH Royal Institute of Technology

Abstract:
Evaluation of non-metallic inclusions in Inconel 718 produced by conventional production and by additive manufacturing A. Karasev, V. Trollbäck, L. Koort, Ch. Hulme It is well known that non-metallic inclusions (NMIs), which are formed during steelmaking processes, can significantly effect on the final properties of steels and alloys. Therefore, it is important to investigate the inclusion characteristics (such as composition, morphology, size and number) in steels and alloys for comparison and optimization of production processes and improvement of product quality. This study focused on evaluation and comparison of main characteristics of NMIs in nickel-based alloy Inconel 718 produced by a conventional production route and by additive manufacturing. Since the common two-dimensional investigations of NMIs on polished metal samples has a number of shortcomings, three-dimensional investigations of NMIs on a film filter and on the metal sample surface after a soft electrolytic extraction were carried out by using scanning electron microscopy equipped with energy-dispersive spectroscopy. It was found, that most inclusions have similar compositions in both samples, However, significant differences were detected in the morphology, size ranges and numbers of the observed inclusions. For instance, the sizes of Nb,Ti-C carbides and Ti,Nb-N nitrides in metal sample produced by additive manufacturing are about 6 and 3 times smaller compared to the conventionally produced sample, respectively. Moreover, the number of inclusions observed in the additive manufactured sample is drastically larger than that in the conventionally produced sample. This is explained by the much higher solidification rate of metal melt in the additive manufacturing process. It was concluded that the electrolytic extraction method with subsequent investigations in the scanning electron microscope can help to determine some significant quantitative differences of NMI characteristics in Inconel 718 samples produced by different production methods. Key words: steelmaking, additive manufacturing, Inconel 718, non-metallic inclusions, electrolytic extraction.

Nella Janáková, Progres Ekotech, s.r.o., Czech Republic

Co-Author:
Martin Gajdzica, Progres Ekotech, s.r.o.

Abstract:
Reducing CO2 Emissions: Industrialization of the hydrogen reduction technology will take some years and further time will pass by until all blast furnaces worldwide will be substituted by hydrogen technology. A bridging technology EcolBriq® offers tremendous value by reducing CO2 emissions on the regular BF production route partially substituting the iron ore sinter process. Recycling of by-products: Recapturing the valuable elements of by products and reducing landfill quantities is another EcolBriq® application creating a cost advantage. The paper presents a cold technology to produce a low-carbon BF feedstock which can be used to supplement the sintering process of iron ore as it is currently known. The implementation of this production process of BF feedstock results in lower energy consumption compared to the high-temperature process of sintering. Thus, there is a significantly lower carbon footprint. In addition, the technology contributes to efficient re-utilization of by-products from metallurgical processes like scale and fractions of dust and slag. A single production line can be utilized for a wide variety of materials as feedstock with different structures, eg: from powder to lumps, minerals like oxide or metal ships with sizes 0-200 mm. The variety of advantages will be discussed: i. Reduction of CO2 emissions for production of the EcolBriq® feedstock compared to sinter ii. Dust reduction for EcolBriq® compared to sinter plant iii. Maximizing the efficiency of the circular economy in BF operations iv. Reducing energy intensity Two case studies will show the results of briquetting two materials which cannot be recycled in sintering plant. First study is focused on briquetting of fine fraction of desulfurization slag and the second one will discuss recycling of oily scales.

Hubert Breukelman, Tata Steel IJmuiden B.V., Netherlands

Co-Author:
Maria Martinez Pacheco, Tata Steel Nederland Technology B.V

Abstract:
The increasingly high demands on European integrated steelworks in terms of sustainability and circularity necessitate the reduction of Greenhouse gas emissions from fossil sources like coke breeze, and require an increase in use of internal waste streams. In this paper, the effect of iron- and steelmaking by-products on sinter productivity and quality are assessed using sinter pot trials. Furthermore, a selective preparation method, the Composite Agglomeration Process (CAP), was used to improve the process characteristics of carbon-rich by-products. This method entails pre-pelletisation of fine-grained components of the sinter mixture on a balling disc, followed by a secondary mixing with the coarse-grained components. To assess the use of the carbon-rich by-products, sinter pot trials were carried out with low (5-10%) and high (15-20%) total by-product content, using the CAP method and conventional granulation. Process monitoring shows that flame front characteristics are strongly influenced by the addition of high carbon by-products when added using conventional granulation, presumably due to combustion kinetics differing significantly from coke breeze. This effect is also observed in the CAP trials, where further effects are observed due to significant differences in sinter bed permeability. The sinter pot trials clearly show that by The CAP method, the replacement factor for coke breeze can be increased, and deterioration of sinter quality caused by high by-product utilization is reduced.

Laura Mariani, Hatch Ltd. , Canada

Abstract:
Electric arc furnace steelmaking now accounts for nearly a third of global steel production. As decarbonization of the industry is pursued through electrification and hydrogen-based direct reduction schemes, the volume of steel produced in EAFs will increase, as will the volume of slag generated as a by-product. Declining ore grades, limited scrap availability, and increased use of DRI will magnify this issue. Valorization of EAF slags has historically met with limited success and many operations simply stockpile or landfill the hundreds of thousands of tonnes of slag they generate each year. Continuation of these strategies is not sustainable and new waste management strategies must be widely adopted. This paper summarizes the factors that will influence future pathways to valorize EAF slags in the context of the development of a truly sustainable steel industry. An outlook for the future of sustainable EAF slag management is also provided.

Mike Duddek, Ruhr West University of Applied Sciences, Germany

Co-Author:
Saulo H. Freitas Seabra da Rocha, Ruhr West University of Applied Sciences

Abstract:
Electrical scrap, particularly battery-powered tools, contain in most cases alloyed steels. These materials are usually incorporated into devices with many other materials, such as copper, aluminium, or magnetic components, making recycling difficult. In traditional recycling approaches, devices are usually shredded as a whole, and the resulting fine fraction is separated in various process steps. This usually generates mixed-metal scrap, as a wide variety of metals are blended. Because of the shredding process, various materials are mechanically bonded (interlocking), making separation difficult, in particular, the separation of softer metals such as copper and aluminium from harder metals such as steel. With a robotised targeted destructive separation of the electrical devices prior to mechanical shredding, this problem can be avoided, and an alloyed steel fraction can be obtained. Using the example of a cordless screwdriver, the separation of the chuck and gearbox from the rest of the device results in a fraction containing only alloyed steel and plastics, without added copper, aluminium or magnetic components, that can be recycled directly in an electric arc furnace. Such targeted destructive fractionation can increase the value of the material stream of electrical scrap and simplify the recovery of high-quality recycled materials. The process of such robotised targeted destructive fractionation and the achieved material qualities are presented in this paper.

Erika Garitaonandia Areitio, AZTERLAN Metallurgy Research Centre, Spain

Co-Author:
Erika Garitaonandia, AZTERLAN Centro de Investigación Metalúrgica

Abstract:
The thermocline Thermal Energy Storage (TES) systems are core elements to boost renewable energies and to improve the efficiency in energy intensive industries. Among TES technologies, air based packed beds storage system represent a promising option since they allow using low-cost materials. The steel slag, a byproduct from the steel production, represents an interesting option as filler material since it fulfils the criteria established in the International Energy Agency (IEA) for TES material, that consist on being inexpensive, available in large quantity without conflict of use, stable up to 1000 °C, compatible with heat transfer fluids and non-toxic. Preceding works have also revealed suitable thermo-physical and mechanical properties to be used as storage material for sensible heat transfer in packed beds. However, one of the critical aspects often not addressed is the durability of the filler material (slag particles) subjected simultaneously to mechanical and thermal stresses over a large quantity of charging and discharging operations. During cyclic thermal charging and discharging, the slag inside the tank is subjected to heavy loads at high temperatures and undergo thermal expansion and shrinkage, which can lead to individual particle degradation and also damage of the tank. For this purpose, different model approaches and tools are addressed in this paper. Specifically designed test rig is introduced in order to test long-term mechanical stability of the steel slag under thermal and mechanical fatigue. Acknowledgements This work has been supported by LIFE programme of the European Union through the Project LIFE20 CCM/ES/001733 ( (https://www.hi4s-life.eu/)

Amanda Vickerfält, Swerim AB, Sweden

Co-Author:
Sichen Du, Hybrit Development AB
Johan Martinsson, Swerim AB
Joar Huss, Swerim AB

Abstract:
The melting progression of hydrogen direct reduced iron pellets containing metallic iron and residual oxides (flux, gangue and unreduced iron oxide) was studied experimentally at 1773-1873 K. It was found that the autogenous slag formed inside the pellet prior to the iron melting. The autogenous slag formation was initiated by the melting of FeO. The liquid FeO dissolved the remaining residual oxides, forming the autogenous slag inside the pellet pores. After the iron melted, the autogenous slag was released from the pores coalescing into droplets. Phase separation occurred as the slag droplets floated up to the liquid iron surface. The melting speed was found to increase with decreased degree of reduction. The reduction degree also affected the partitions of phosphorus and vanadium between slag and metal.

Sa Ge, Hatch Ltd., Canada

Co-Author:
Kamal Joubarani, Hatch Ltd.
Terrence Koehler, Hatch Ltd.
Ian Cameron, Hatch Ltd.
Chris Walker, Hatch Ltd.
Kyle Chomyn, Hatch Ltd.

Abstract:
The future of steelmaking requires changes to existing integrated process flowsheets and application of new technologies to achieve significant reduction of greenhouse gas (GHG) emissions, i.e., green steel production. One such novel approach is the use of direct reduced iron (DRI) coupled with an electrical smelting furnace (ESF) to produce hot metal for downstream steelmaking, and thus replacing the blast furnace (BF) – the biggest GHG emitting process step in the value chain. The DRI-ESF process capitalizes on the lower Scope 1 GHG emissions from direct reduction and electric furnace processes versus BF, as well as the effective gangue rejection and slag valorization capability of ESF to improve raw material flexibility. The complexity of the iron and steel value chain and the rapidly evolving decarbonization technology landscape mean that the implementation of the DRI-ESF concept requires bespoke flowsheet development and thorough assessment of many potential options to be effective. The present study examines various potential flowsheets centred around the DRI-ESF concept, considering the key choices in flowsheet development such as DRI reductant (hydrogen or natural gas or both), specification of intermediate product, grade and type of iron ore, ESF slag valorization, downstream steelmaking technology, and the ultimate transition to ESF-based direct steelmaking. High level process and cost models were developed to simulate archetypal flowsheets, and these flowsheet cases are critically assessed with emphasis on comprehensive economics, overall GHG emission benefits, and level of technical / implementation risks. Potential risk mitigation options, enabling / synergistic technologies, and preferred implementation scenarios were also identified and discussed.

Reinoud van Laar, Danieli Corus B.V, Netherlands

Co-Author:
Bart De Graaff, Danieli Corus B.V

Abstract:
The majority of steel to date is made by BF-BOF, but the iron- and steelmaking industry is more frequently evaluating alternative plant configurations to reduce CO2 emissions. These include DRP and EAF technologies, but also new electric smelter technology to convert low-grade DRI pellets to hot metal to retain BOF steelmaking plants. The development of this technology eliminates future constraints to DR-grade pellets and could allow usage of slag for the production of cement. However, there are many challenges in the process design of industrial electric smelter technology including carburization particularly when hydrogen is used for the production of DRI. This paper will address potential plant configurations including electric smelter technology. It will also address a preliminary assessment of electric smelter technology and metallurgy and identify challenges and risks.

David Rudge, Hatch Ltd., Canada

Co-Author:
Sa Ge, Hatch Ltd
Terry Koehler, Hatch Ltd
Chris Walker, Hatch Ltd

Abstract:
The future of steelmaking requires changes to achieve significant reduction of greenhouse gas emissions, using new process flowsheets. One approach commonly considered is the use of direct reduced iron (DRI) with an electrical arc furnace (EAF); however, this poses significant challenges when using lower grade ores / pellets and in the future when using hydrogen-DRI. This paper describes a method to improve the process yield and efficiency, using an electric smelting furnace technology. The smelting furnace (ESF) efficiently converts DRI into pig iron (hot metal), which can be used downstream in an EAF or basic oxygen furnace (BOF), or cast / granulated for future use. The smelting furnace leverages advanced furnace technology developed over 60+ years for ironmaking and ferro-nickel applications, and has also been demonstrated for direct steelmaking. These furnaces are operated continuously with high power and large throughputs. Technologies have been developed, tested, and optimized to ensure safe and efficient operation, and a long furnace campaign life. This new approach eases the shift to green steelmaking by using existing facilities and pellet supply chains, and provides higher yields and reduced lifecycle costs.

Andre Esterhuizen , Tenova South Africa Pty Ltd, South Africa

Co-Author:
Piet Jonker, TENOVA South Africa Pty Ltd
Marco Corbella, Tenova S.p.A.

Abstract:
With the global steelmaking industry’s focus on the decarburization of the steel making process, Tenova has developed iBlue®, a novel technology that combines conventional smelting furnaces with the Energiron® Direct Reduction technology - jointly developed by Tenova and Danieli - to replace the blast furnace process, using low grade pellets (± 62% FeO) as virgin iron sources. To maximize the yield of the hot metal produced, and provide operators with a flexible plant design that can cater for a wide range of inputs, key design decisions are required to ensure an optimal flow sheet. This paper explains in detail the decision making process in the DRI melter design, touching on raw material feed requirements, metal handling, carbon balancing, electrical system design and management of the off gasses produced in the reducing atmosphere. These concepts will be evaluated from both a control volume and process design point of view. The conduction of the melter process is closely connected to the DRI production process and there are substantial benefits in the interconnection of the ENERGIRON® plant and the melter from an overall quality and efficiency perspectives. The paper analyzes the benefits of a closed furnace design for this application, as it operates in a reducing environment, allowing for minimal losses of FeO to the slag. Lastly, slag conditioning and management is described: matching the chemical composition requirements for the cement industry (not possible using an EAF) is a key benefit of this solution which can be truly considered as the evolution of the blast furnace technology. Key Words Hydrogen, DRI, HBI, BF, BOF, EAF, FMF, H2, reducing gas, carbon footprint, decarburization, ENERGIRON ZR, CCS, CCU, smelting reduction furnace, OSBF, ENERGIRON

Bartosz Mertas, Institute of Energy and Fuels Processing Technology, Poland

Co-Author:
Robert Baron, Koksownia Częstochowa Nowa Sp. z o.o
Sten Yngve Larsen, Eramet AS
Michał Książek, Sintef AS
Anna Rodź, Institute of Energy and Fuel Processing Technology
Grzegorz Gałko, Institute of Energy and Fuel Processing Technology
Małgorzata Wojtaszek-Kalaitzidi, Institute of Energy and Fuel Processing Technology
Michał Rejdak, Institute of Energy and Fuel Processing Technology
Bartosz Mertas, Institute of Energy and Fuel Processing Technology

Abstract:
The carbothermal reduction process is used to produce manganese ferroalloys. One way to reduce CO2 emissions from the process in which coke is used would be to replace fossil carbon with renewable biomass carbon, which is considered to be carbon neutral. One of possibilities is to use bio-coke as a substitute for typical coke made of only fossil coking coal. Bio-coke can be manufactured on the basis of coking coal with the addition of materials of biomass origin. Blends for the production of bio-coke should have acceptable cokemaking properties to allow to produce bio-coke of appropriate quality. The paper presents the results of the on-going research project on the influence of the addition (up to 20%) of bio-materials of different origins to the coal blend on its cokemaking properties, i.e., Gieseler Fluidity, Arnu—Audibert dilatation and caking ability (Roga Index). The bio materials used in the research were raw and thermally processed waste biomass of different origins (forestry: beech and alder woodchips; sawmill: pine sawdust; and the food industry: hazelnut shells and olive kernels) and commercial charcoal. Presented results show that the amount of additive as well as the type of material affect the obtained coking properties. The presentation also contains the results of the quality parameters of bio-coke made on the basis of a coal blend with the addition of up to 20% of thermally processed biomass - charcoal. The evaluated parameters were: reactivity to CO2 (CRI), CSR post-reaction strength, structure and texture parameters. The presentation will also show the results of earlier research conducted at SINTEF: CO/CO2 reactivity, electrical resistivity and reactivity to MnO (slag-reactivity). Studies have shown that the quality parameters of the bio-coke produced on a large-laboratory scale meet the requirements for the reductant in the process of smelting manganese ferroalloys in submerged arc furnaces.

Andrey Stephan Siahaan, Tohoku University, Japan

Co-Author:
Shungo Natsu, Tohoku University
Hiroshi Nogami, Tohoku University

Abstract:
Burden-charged distribution in the top region of the iron-making blast furnace is an important issue, as the non-uniform distribution in this part may affect the gas flow, heat transfer, and chemical reaction inside. The rotary chute plays the role to deliver material from the hopper to the furnace top, and it comes in different sizes, which will eventually establish distinct particle movements while charging. In that regard, it is vital to understand the fundamentals of particle movement that determine burden distribution inside a blast furnace in corresponds to chute sizes. In this study, a three-dimensional model of the furnace-top and rotating chute was established to clarify the material movement and burden distribution of ore and coke (O/C), investigated at the particle scale using the discrete element method (DEM). Case studies of various chute sizes (length and diameter) were varied to analyze their influence on material flow behavior inside the chute during charging. The change of heap profile of O/C centralized or peripheralized layers during charging was analyzed on the effect of various chute sizes. In addition, the cross-section of ore and coke layers was examined, where the layer thickness and volume fractions on radial distance of each case were mapped and compared.

Pietro Cosentino, ArcelorMittal, France

Co-Author:
Sami-Alex Zaïmi, ArcelorMittal

Abstract:
Controlling the charging of the blast furnace is essential to ensure the burden distribution needed for a stable operation, high performance, low coke consumption and low CO2 emissions. The goal of this work is to study the impact of the chute geometry on the stream of particles. DEM has been chosen as the mathematical approach for simulating the granular flow. A series of simulations has been performed with modified geometries to study their impact on the stream of particles. To quantify that impact, the main aspects monitored were the thickness and the speed of the stream at the tip of the chute. The results showed the importance of simulating the proper geometry of the chute, as minor geometrical changes can have a big impact on the results. That approach brings perspectives on how to improve the geometry of the chute and on how it can influence the burden distribution in the furnace.

Jiook Park, POSCO, Korea, Republic of

Co-Author:
Dong-jo Lee, POSCO

Abstract:
To meet the unprecedented demand of environmental issues and tightened production cost, fuel consumption to produce iron and steel must be minimized to the limit. In blast furnace, maintaining circumferentially balanced state is critical for stable operation and minimizing fuel rate. Circumferentially unbalanced state of furnace will result irregular burden decent, thermal level instability and poor gas utilization and so on. Hence, furnace operators carefully monitor circumferential information of furnace and take several actions to keep furnace stable. Among several actions, burden profile control is one of the most effective actions to change inner state of furnace and achieve minimized fuel rate. Generally, optimum burden profile can be attained by rotating chute control (speed, angle, etc.) in bell-less type blast furnace. Unfortunately, in conventional control concept, only radial directional burden control is possible while there is barely no tool to control circumferential burden profile. In this study, circumferential burden stock level balancing system was developed for circumferential burden profile controlling and balancing. To decide when/where to control, furnace circumferential information such as top gas temperature, sounding level and tuyere combustion status were continuously monitored and key control parameters were derived from DEM burden decent simulation of bell-less top charging system. Once burden stock level of specific direction is too low or too high, top charging system was controlled to attain flattened stock level. Developed system was installed and tested at Pohang No.3 Blast furnace and it was found that standard deviation of 4 direction’s stock level can be effectively reduced by the system.

Peer Eric Günther, Hüttenwerke Krupp Mannesmann GmbH, Germany

Co-Author:
Thomas Sturz, Hüttenwerke Krupp Mannesmann GmbH

Abstract:
Within the steel industry it is commonly known that slopping of slag and molten steel occurs in the BOF. Whilst searching for the reasons of slopping is still part of much research, it is also of interest how to manage these events of slopping and how to predict them as slopping events are problematic for environmental reasons and costly in their removal. Within the steel mill of Hüttenwerke Krupp Mannesmann GmbH (HKM) a technology for prediction of slopping is developed using acoustical analysis. The implementation of this technology is described, as well as the results to predict and to prevent excessive slopping of the converter vessel.