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.

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."

David Smart, Materials Processing Institute, United Kingdom

Co-Author:
David Stamp, Materials Processing Institute
Andrew Chown, Materials Processing Institute

Abstract:
For all caster operators, the challenge is to cast both established and new steel grades at ever increasing casting speeds, whilst maximising prime cast product and ensuring the security of the casting machine, that is, no strand breakouts. Consequently, the requirement to monitor and control solidification in the casting mould continues to be the focus of a multitude of research and development activities. This paper details the development and testing, at the UK's Materials Processing Institute’s pilot caster, of two novel technologies, both applied to the hot face of the casting mould. Firstly, the innovative application of a thin film thermocouple array for direct temperature measurement of the liquid and/or solid mould slag, and secondly use of intumescent coatings to reduce heat extraction at the meniscus region. These research and development activities have been supported by the European Research Fund for Coal and Steel,

Rodrigo Madrona Dias, Usiminas S. A., Brazil

Co-Author:
Fabiano Moreira, Vesuvius
Saku Kaukonen, SAPOtech Oy
Rodrigo Seara, Usiminas S.A.
Rodrigo Madrona, Usiminas S.A.
Maria Maria Carolina Campos, Vesuvius
Márcia Maria da Silva Monteiro Pereira, Vesuvius
Hannu Suopajärvi, SAPOtech Oy
Fernando Quinelato, Vesuvius
Gabriel Ribeiro, Vesuvius
Joilson Moreira, Vesuvius
Moises Miranda, Vesuvius
Vasco Esteves, Vesuvius
Hervé Tavernier, Vesuvius
Maxwell Rogana , Vesuvius

Abstract:
One of the most important functions of mold fluxes is to maintain and improve semi-product (slab, bloom, billet) surface quality through a continuous lubrication, and a controlled heat transfer between the solidifying steel shell and the mold. Typically, the evaluation of the mold flux performance and impact on the semi-product surface quality is conducted manually by a skilled professional. There are many drawbacks with this current approach. Manually conducted visual inspection takes a lot of time, there is a long delay as the surface cannot be inspected until the semi-product has cooled down, and the documentation of the findings is many times insufficient. In some cases, it is not even possible to inspect the surface if the semi-product is directly forwarded to a conditioning step (scarfing/grinding) or to a hot rolling mill. To overcome the inefficiencies described above, this paper presents an approach where automatic surface inspection system is used to evaluate the slab surface quality and the performance of mold fluxes. It is shown that the system can be easily and effectively used to evaluate casting fluxes behavior on both peritectic and ultra-low carbon steel grades, allowing to reduce operational and quality risks and to go faster in the qualification of new and improved mold fluxes

Stefan Senge, Tata Steel Ltd , Netherlands

Co-Author:
Wilfried Klos, SMS group
Matthias Vogd, SMS group
Artemy Krasilnikov, SMS group
Rudi Kalter, Tata Steel Ltd
Arnoud Kamperman, Tata Steel Ltd
Jan Kromhout, Tata Steel Ltd
Claire Dwyer, Tata Steel Ltd
Ton Spierings, Tata Steel Ltd
Jacco van 't Hul, Tata Steel Ltd
Mariëlle Wiegman, Tata Steel Ltd

Abstract:
Wear of the copper mold plates has a major contribution on maintenance costs of thin slab casters. In the upper part of the mold, this wear is caused by high heat loads which leads to crack formation in the copper surface. In the lower part of the mold, mechanical load resulting from the interaction with the strand passing by is the main reason for wear. Trials were performed in the thin slab caster at Tata Steel in IJmuiden, using a variable thickness nickel coated mold plate. In the upper part of the mold this is combined with a specific surface roughness to reduce the thermal load locally. In the lower part of the mold the coating layer is thicker and is applied without any surface structure with the aim to reduce the mechanical wear. During these trials, optical fibers (FBG) were used to assess the local temperatures and heat flux in the copper mold. The overall geometry of the mold plate was measured during the trials to evaluate the effect on wear of the mold plate. Analyzing the heat flux, it was shown that modifying the surface of the copper mold plate resulted in a reduced heat transfer. The thermal resistance of the coating layer and surface roughness measured using the integral heat flux, is comparable to 10 mm of copper thickness. Comparing casting situations with similar process conditions, the local heat flux measured just below the meniscus showed a reduction of up to 26 %.

Marc Köster, VDEh-Betriebsforschungsinstitut GmbH, Germany

Co-Author:
Piero Frittella, Feralpi Group
Jörg Bellmann, ESF Elbe Stahlwerke Feralpi GmbH
Ralf Schuster, ESF Elbe Stahlwerke Feralpi GmbH
Matthias Groll, ESF Elbe Stahlwerke Feralpi GmbH
Waldemar Krieger, VDEh-Betriebsforschungsinstitut GmbH
Martin Schlautmann, VDEh-Betriebsforschungsinstitut GmbH

Abstract:
For the first time, a laser vibrometer system in combination with appropriate artificial intelligence methods for clustering of the measured vibration spectra has been tested at a continuous casting machine to receive information on the solidification status of the strand. Measurements with the laser vibrometer at a fixed strand position of the billet caster of ESF under conditions of incrementally increasing casting speeds revealed a transition in the population of the identified vibration clusters as a footprint of the passed crater end position with a change from a fully solidified strand to a strand with some liquid core at the measurement position. This was in accordance with the results from a three-dimensional dynamic temperature and solidification model which has been set up based on a state-of-the-art approach for solution of the heat flow equation with tailored sub-models for the different boundary zones of the ESF billet caster (i.e., mould, secondary spray water zones and radiation zones) and installed at the steel plant for online monitoring and control of the casting process. The application of the newly installed measurement and model-based information systems at ESF revealed significant improvements of their billet casting process in terms of reduced strand breakout rates and increased productivity.

Volodymyr Omelchneko, thyssenkrupp Steel Europe AG, Germany

Co-Author:
Sven Karrasch, thyssenkrupp Steel Europe AG
Christoph Toulouse, thyssenkrupp Steel Europe AG
Sascha Lang, thyssenkrupp Steel Europe AG

Abstract:
The Continuous Casting Machine (CCM) Bruckhausen is part of an integrated steel plant of thyssenkrupp Steel Europe in Duisburg. The main customers are the market leaders in the packaging, automotive and electrical industries, who set high standards regarding the surface quality of their products. Due to the closeness of CCM and hot-rolling mill in Bruckhausen, the transition time of the slabs from CCM to the hot-rolling mill is quite short. This shortness has two main advantages. Firstly, it allows to save energy which is needed for reheating of slabs. Secondly, slabs with short transition time have fewer micro cracks on the slab surface. The short transition time, however, brings a big challenge for the production process, since it limits the time available for the quality control of the slab surface and exclusion, if defects are detected. The most frequent defects on slabs are longitudinal and transversal flame-cutting burrs/beads and different types of cracks. In the past, the slab surface was controlled by means of thermal camera to detect those surface defects. This technique has reached its limits regarding the present challenges for the quality of the slab surface. To fulfill continuously increasing customers surface quality requirements, in March 2022 we implemented the first slab surface inspection system of thyssenkrupp Steel. It is a 3D Surface Inspection System (SIS) supplied by IMS Messsysteme. Within six months after the installation of the 3D SIS the internal quality costs as well as quality KPIs of our customers had been improved. After giving a brief introduction in the principals of 3D SIS technique we will present the main advantages of the 3D SIS in comparison to a basic thermal camera detection system, the recent impacts on quality results and next planned development steps.

Reinhold Leitner , Primetals Technologies Austria, Austria

Co-Author:
Christoph Aigner, Primetals Technologies Austria
Thomas Zauner, Primetals Technologies Austria

Abstract:
"The entire steel industry is going through the irreversible process of digital transformation and increasing plant automation to meet the requirements in terms of productivity, safety, quality as well as increased flexibility in production. A digital caster has many challenges and sub-tasks that must be achieved along the way to end up with a fully digitalized plant operation. The fully integrated casting platform with automatic controlled sequence operations starting from connecting the ladle on the turret to fully automatic tundish operation and start cast by means of robots and highly integrated automations systems limits the need of operator interventions to an absolute minimum. Thus, not only results in a reproduceable high quality caster operation but also increase operator and machine safety. One crucial aspect is controlling the casting speed of the plant by an advanced expert system right from start cast until the last slab has been cut. All influencing factors such as optimal soft reduction, the casting practice or machine restrictions are brought together to calculate an optimal casting speed throughout the entire casting process. The paper gives an overview about a digital caster and outlines the latest innovations in continuous casting automation on the way to a fully automated caster. "

Gerald Hohenbichler, Primetals Technologies Austria, Austria

Co-Author:
Marvin Zemni, Primetals Technologies Austria

Abstract:
Predictive Maintenance starts with IIoT. Excellent and reliable sensorics are the first hardware basement for lifetime and failure prediction for production machinery and plants. Therefore Primetals Technologies started technology development programs in data mining as well as condition monitoring and smart sensoric, even though the first approach has always been to perform condition monitoring without additional sensor implementation, where possible. A major source of unplanned downtimes of continuous slab casting plants are stuck bearings in the strand guide area. Hence Primetals Technologies has been realizing a prototype development creating a new middle bearing block with embedded sensors and an onboard tiny central processing unit, able to wirelessly transfer all interesting load data and performance indicators to the operators of the plant and to the maintenance personnel. The plant manager gets an overview about the overload events shift-by-shift or daily, weekly, and monthly, respectively. This paper provides a great insight into the first industrial prototype results.

Pierpaolo Rivetti, SMS Concast AG , Switzerland

Co-Author:
Stephan Feldhaus, SMS Concast AG
Shuai Niu, Nanjing Iron & Steel Co., Ltd.
Xinghua Chen, Nanjing Iron & Steel Co., Ltd.
Wei Deng, Nanjing Iron & Steel Co., Ltd.
Zhiyong Hu, Nanjing Iron & Steel Co., Ltd.

Abstract:
The present study focusses on the internal quality improvement of the spring (54SiCr6) and bearing (GCr15) steel blooms by optimizing the MSR (Mechanical Soft Reduction) and MHR (Mechanical Hard Reduction) process parameters on the continuous casting machine supplied by SMS Concast AG at Nanjing Iron &Steel Co. In addition to MSR and MHR, the caster is equipped with electromechanical stoppers, mold electromagnetic stirrer (M-EMS), final electromagnetic stirrer (F-EMS) and air-mist spray cooling. State of the art L1 and L2 software complete the technological packages for this machine. Solidification status of the blooms with sections of 255 mm x 300 mm and 330 mm x 420 mm were determined by using the verified FEMS solidification model provided by SMS Concast AG. Theoretical effective reduction region was proposed based on the simulated crater end position of the blooms. Intensive industrial trials were conducted to study the effect of the reduction rate on the V-shaped and centerline segregation of the blooms. The results show that obvious improvement of internal quality of the spring and bearing steel blooms of both sections could be obtained by increasing the reduction amount and applying a suitable reduction rate in the effective reduction region during casting.

Michael Riedler, Primetals Technologies Austria, Austria

Co-Author:
Gerald Hrazdera, Primetals Technologies Austria
Thomas Lengauer, Primetals Technologies Austria
Josef Watzinger, Primetals Technologies Austria
Denijel Burzic, Primetals Technologies Austria

Abstract:
"In order to maintain a sustainable planet for our children, the objective of decarbonization is drastically reducing carbon dioxide emissions. In the steel industry this leads to the replacement of classical BOF production as well as a change in raw material towards HBI and DRI. This changed process routes confront continuous slab production with new challenges. While liquid steel input is changed in composition and residual elements, cast products have to maintain the same quality level as expectations on final product remain unchanged. These challenges require new, flexible sensors and actuators integrated into the continuous slab caster. In addition to the support provided by advanced automation systems, this includes, among other things, an increasingly fine setting of the casting gap and the application of innovative cooling practices, as well as an active flow control through electromagnetic actuators. In terms of immediate adaptation to the changing requirements, these systems and actuators should be selected in such a way that they can be integrated also into existing continuous casting machines. This article discusses successfully implemented systems in process routes with non-BOF steel production in combination with continuous casting plants."

Peter Presoly, Montanuniversität Leoben, Austria

Co-Author:
Daniel Kavic, Montanuniversität Leoben
Christian Bernhard, Montanuniversität Leoben
Susanne Hahn, Primetals Technologies Austria
Sergiu Ilie, voestalpine Stahl GmbH

Abstract:
Modern steel grades are subjected to constant development to perform weight reduction, energy-saving, and automobile safety performance. In the last decades, high strength and ductile steels were developed with increasing quantities of silicon and manganese. Three of these alloying concepts are Dual-Phase (DP), TRansformation Induced Plasticity (TRIP) and even TWinning Induced Plasticity (TWIP) steels. All these steel grades are based on the iron-carbon-manganese system with additions of ferrite former such as silicon and/or alumina, followed by micro-alloying elements. The main difference compared to previous steel grades are the significantly higher levels of ferrite formers. Apart from the research on these new steels' material and product properties, the knowledge about the production process, particularly the continuous casting (CC) and the initial solidification in a water-cooled copper mold, is of significant importance. In this regard, the high-temperature phase transformation temperatures and the thermodynamic properties play a particular role. An efficient pre-identification of hypo-peritectic steel grades by experiments or thermodynamics is relevant to ensure surface quality, productivity, and operational safety in the casting process. The potential of different laboratory experimental methods and thermodynamic approaches is critical evaluated in comparison with operational experience from voestalpine Stahl Linz. Since process data in the continuous casting process often overlap with different operating influences (e.g. casting speed changes, width adjustments…), a new approach is presented to identify the process behavior of peritectic steels without additional effects. For this purpose, operating data from the mold monitoring were processed statistically, and only data areas with a steady-state casting length of more than 100 m were used for further consideration. Using this data preparation method, the peritectic area in the continuous casting process can be clearly described. Statistically prepared process data and experimentally verified thermodynamic data are the basis for the development and validation of demanding process models.

Eloy Martinez Rehlaender, SvMet Engineering S.A., Mexico

Abstract:
Casting operating temperatures for thin slab casting are key to achieve production levels that are comparable to conventional slab casting. Casting temperatures also determine key quality factors like internal segregation. Even more important is the effect of superheat on mold powder behavior during casting. It is well known that mold powders can have critical transformations in the mold which in turn change the heat transfer characteristics. In this paper it is shown that achieving superheat control for thin slab casters can be done with the use of hybrid models. Hybrid models results show clear advantages such as very narrow window of operation for any steel grade. {15~30 C and 20~30 C}. It is also shown that heat sequence transition is much faster with the use of hybrid models.

Pavel E. Ramirez Lopez, Swerim AB, Sweden

Co-Author:
Anton Sundström, Swerim AB
Joakim Eck, Swerim AB

Abstract:
Steelmaking processes occur at high temperatures (in excess of 1500° C) which makes experiments and measurements on liquid steel very difficult. A good alternative to model the behaviour of liquid steel is to use low-melting point alloys with similar density and viscosity (for example: Bi-Sn, Tmelting: 150°C). SWERIM is home to one of the most advanced facilities for physical modelling with liquid metal for casting in the world. This facility is used as benchmark to test flow control devices such as nozzles, stoppers and sliding gates during continuous casting operations. The present manuscript describes recent work to increase the size of the simulator to full-scale for wide and thick slabs as well as reaching casting speeds and Argon flow rates equal to those applied in the Industry. The Simulator has been also equipped with a series of measurement techniques to monitor pressure, velocity, temperature, level fluctuations and vibration in order to fully characterize the metal flow in CC moulds. Finally, the present paper enumerates the main findings, challenges and limitations derived from extensive tests in the simulator with real ceramic nozzles/stoppers and their counterparts in stainless steel.

Simone Cicutto, ergolines Lab s.r.l., Italy

Co-Author:
Isabella Mazza, ergolines lab s.r.l.
Giovanni Schiavon, ergolines lab s.r.l.
Stefano Spagnul, ergolines lab s.r.l.

Abstract:
Ergolines’ Ultrasonic Level Detector technology is an innovative technological solution for the contactless measurement of steel level in open stream casting. This technological solution is based on real-time measurement of the thermal profile in discrete points, based on the time of fly of ultrasonic waves in the copper tube. This technology, contrary to thermocouples and optical fibres, is contactless and, being installed on the water jacket, requires no machining of the copper tube. UT-LEVEL is the application of this innovative technology finalized to measure the copper temperature in the meniscus area, generally covering a length of 210mm. Based on the thermal profile data gathered, a dedicated algorithm extracts the steel level position, namely meniscus. Thanks to the fast response of the sensor and the high-performance electronic computation, the dynamic of the solution is aligned with the radiometric technology, utilized for the steel level control in most of the continuous casting machines worldwide. In detail, UT-LEVEL field of application is open stream casting process. An additional advantage of this solution is that the data of the thermal profile are visible in a dedicated HMI, and the rear data are available to the CCM for process optimization. Some systems of this not-radioactive technological solution for steel level control have already been installed and are currently operative.

Hongliang Yang, ABB AB, Sweden

Co-Author:
Jan Erik Eriksson, Proximion AB
Gunnar Hedin, Proximion AB
Krister Fröjdh, Proximion AB
Dieudonne Nkulikiyimfura, ABB AB
Peter Rybing, ABB AB
Fredrik Axelsson, Alleima AB
Karin Hansson Antonsson, Alleima AB

Abstract:
Understanding of heat transfer mechanisms in a bloom caster mould allows producers to find optimal casting conditions to improve quality and avoid remedial conditioning for different cast formats and grades. A method to produce optimization measures to avoid cracking by modifying mould heat transfer to increases the flexibility and enhances the resource efficiency during CC. To achieve this Alleima (former Sandvik Materials Technology) installed a newly designed fibre optical sensor system from Proximion. The new Fibre Bragg Grating sensors system gives high density measurements of mould temperature and reduces maintenance costs of industrial application in bloom casters using sensors for long term use and measurements that are easy to move between different moulds. The system gives possibility to in detail follow mould temperature on all four bloom sides in real time during casting using 1380 sensor points. ABB has developed and installed an advanced OptiMold Monitor® for the caster with a high potential to increase both yield and quality. This is accomplished through an enhanced understanding of relationships between the measured mould temperature, process parameters and final product quality. The installation opens new opportunities for real-time control and monitoring of the CC process giving the operators and plant engineers possibilities to visualize what is happening in mould during casting for different steel qualities. By using the installed system, it has become possible to characterize thermo-physical properties of casting powders in detail which is used to improve thermal conditions at the meniscus.

Thomas Griessacher, Stahl- und Walzwerk Marienhütte GmbH, Austria

Co-Author:
Daniel Ott, Primetals Technologies Austria
Helmut Hlobil, Primetals Technologies Austria
Oliver Lang, Primetals Technologies Austria

Abstract:
For more than one and a half years ShapeMon Billet Bloom is installed now at Stahl- und Walzwerk Marienhütte GmbH in Graz. The system inspects their two lines of billet production. While the starting focus was on reliable length measurement and weight calculation, the modular design of the system with laser line projection, and cameras for evaluation of laser line and surface, shows more and more tasks, that can be fulfilled by the measurement device. With the high data acquisition frequency strand jerking is detected by the system and a warning is generated in case of excessive jerking. It indicated that the mold taper does not fit to main parameters like casting speed, oil or powder used for lubrication. At best the jerking detection can help to prevent sticker breakouts. The second use case for quality inspection via data analysis of the system, is the detection of surface cracks. With image analysis it is possible to detect longitudinal as well as transverse cracks, classified into two categories. Severe ones that may cause breakouts while being straightened and smaller ones that reduce the quality of billets and may create problems in the rolling process. Also, when cracks are detected, alarms are generated to inform operators and assist them in deciding on appropriate actions such as adjusting casting speed, water flows, etc. Marienhütte was able to reduce breakout rates by approximately 80% and transverse crack surface defects close to zero with this system installed at the billet caster.

Lothar Fischer, SMS group, Germany

Co-Author:
Martin Friedrich, SMS group
Stephan Six, SMS group
Jochen Wans, SMS group
Matthias Kampf, SMS group

Abstract:
SMS group presents an overview of intelligent technologies. HD LASr [strand], HD mold and HD scan are essential instruments for the sustainable improvement of slab quality. HD stands for High Definition or the possibility to get a more detailed insight into the process with the action option. The HD products accompany you throughout the entire process. The positive feedback from our customers clearly shows the intensity with which SMS group develops continuous casting for current and future challenges. With the aim of making the checking easier, more precise and reliable the digital aligning assistant HD LASr [strand] has been developed basing on the well-proven 3D Lasertracker measuring technology. HD LASr [strand] can be used for measuring the strand guide in the caster itself: the position of the surface of mold copper plates, mold foot rollers and segment rollers of the vertical strand guide part. The HD moldFO - fiber optcal mold monitoring system from SMS group provides high-resolution view insight into the solidification process. Operator guiding assistance of the HD moldFO contributes to a safe plant protection serving for high yield production of prime quality slabs. The next generation HD moldFO+ stands out with crucial enhancement, namely permanent connection between fiber optics and evaluation unit. A fiber optical cabling between the mold and PLC-Room is not needed, so it is more maintenance-friendly. HD scan is the ultrasonic measuring system of the future for classifying the internal quality of cast products. The quality of cast products is the crucial economic factor not only for manufacturers and for retailers, but for further processing companies and consumers too. The software to evaluate the data produces objective, valuable reports on the internal quality of cast products. HD scan is easy to operate, the method is reliable, and the results are reproducible.

Simone Cicutto, ergolines Lab s.r.l., Italy

Co-Author:
Isabella Mazza, ergolines lab s.r.l.
Giovanni Schiavon, ergolines lab s.r.l.
Stefano Spagnul, ergolines lab s.r.l.

Abstract:
During the last years, the importance of powder feeding has become more and more central for the optimization of the continuous casting process with submerged stream. A first technological step ahead has been the introduction of the powder feeder enabling to keep constant the addition of lubricating powder and keep homogenous its distribution. A huge added value is given by the powder thickness control in close loop. This is possible thanks to the integration in the system of a dedicated sensor which operates by comparison with the main sensor for steel level control. The advantages of this solution are several, as keeping constant the thickness of lubricating powder, reducing the steel level fluctuation, reducing break-outs risks, reducing powder entrapments into liquid steel. The solutions for the powder thickness control here reported are classifiable in two families: sensors to be installed on the casting floor (as for example laser triangulation) and sensors installed in the mould assembly (as UT-POWDER installed in the water jacket/backplate). The sensor for powder thickness control installed on the casting floor presents the advantage that one sensor is common for more casting sizes, but there are limitations due to geometrical dimensions, to steel level sensor characteristics, and also to the operativity, being installed on the casting floor. The UT-POWDER, ergolines solution installed in the mould assembly, presents several advantages such as non-interference on the operativity of personnel on the casting floor, a wider application range, and the possibility to gather some additional information as thermal profile in the meniscus area.