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.

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.

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.

Matthias Schmidtchen, Technische Universität Bergakademie Freiberg , Germany

Co-Author:
Max Weiner, Technische Universität Bergakademie Freiberg
Christoph Renzing, Technische Universität Bergakademie Freiberg
Max Stirl, Technische Universität Bergakademie Freiberg
Ulrich Prahl, Technische Universität Bergakademie Freiberg

Abstract:
New groove pass series for long products must be developed by backward engineering starting with the necessary mechanical properties and geometry of the final shape, with a highly iterative manual effort and with numerous manual decisions. Usually, established groove sequences are adopted in this process with-out consideration of material requirements of the rolled materials and work roll limitations, while other groove shapes may provide better final results. In order to achieve precision in the material flow, time consuming FE-Methods are already being used in the reverse engineering. The aim of the presented fast approach is to obtain an optimal roll contour for simple irregular groove sequences using generalized, roll-technical justified and experimentally evaluated design criteria coupled with a fast 3D approach for stress state, material flow and fast approaches for the assessment of the elastic stress state resp. work safety of the rolls. By direct coupling the material flow calculation e.g. with fast microstructure models the microstructure development and the required end properties are integrated into the optimization process. Examples for selected steel grades will be discussed. Parts of the calculation code shown and discussed are available via the open source project - PyRoll - which is continuously updated by the Center of Groove Pass Design of TU Bergakademie Freiberg and free available within the terms of the license [1, 2]. The Python-based framework package allows maxi-mum adaptability to own needs via a flexible plug-in system for own code additions. [1] https://github.com/pyroll-project [2] https://tu-freiberg.de/en/fakult5/imf/ikz

Axel Rimnac, Primetals Technologies Austria, Austria

Co-Author:
Konrad Krimpelstaetter, Primetals Technologies Austria
Alfred Seyr, Primetals Technologies Austria

Abstract:
"This paper presents a web-based system that describes the interaction of a hot rolling mill and the rolled material. It represents a combined digital twin simulation of the plant and the product in terms of temperature-time deformation behavior resulting from the specific rolling schedule of a customer-specific plant, be it e.g., a hot strip mill, thin-slab casting and rolling facility, Steckel- or heavy plate mill. This tool is combined with a model to describe the microstructure evolution of the processed material. The physical description of the material is based on evolution equations for the austenitic phase regarding recrystallization, grain growth, precipitation of various compounds as well as austenite decomposition including a prediction for as-rolled mechanical properties for the cold material based on the phenomenological description of well-known strengthening mechanisms and their combination for multi-phase steels. The description of the interaction between process equipment and product is considered by using derivates of in-house design models that have precise parametrizations for mechanical as well as thermal interaction with the processed material. Extensive information computed on forces, torques, temperatures, throughput, and microstructural information as well as predictions on capability constraints are available via corresponding visualization including proper export functionality for the generation of e.g., reports. In this way the user is in the position to gain detailed insight in the hot rolling process, e.g. the analysis of already produced materials or performing what-if analysis to acquire information on upcoming products in a development cycle. The computation facilities are hosted by Primetals Technologies. Customer access is established via a standard web browser and customer Know-How is fully protected by using high level state-of the art security mechanisms."

Alessandro Ferraiuolo, Marcegaglia Carbon Steel S.p.A., Italy

Co-Author:
Lorenzo Ferraiuolo, Mathematics - UNIBO

Abstract:
ABSTRACT In the present paper is presented a novel physical approach aimed to evaluate the workpiece work hardening during rolling process. The evaluation of the work hardening offers the possibility to build up an incremental plasticity model to be applied for the investigation of microstructure evolution during actual industrial processing. The proposed approach is articulated into two steps: the first step it consists in introducing a new concept: the effective work hardening that includes the sum of two distinct additive contributions: 1) the microscopic work hardening, due to dislocations interaction with forest dislocation and 2) the plastic hardening/softening related to Von Mises plasticity condition under multiaxial stress state. The effective work hardening of the workpiece in the rolling process under plane strain conditions is evaluated on the basis of classic Orowan-Alexander rolling process equation and assuming the normal stress distribution along the roll bite as described by Bland-Ford equations. Following this approach, the equilibrium equation along the contact arc assumes the form of a differential equation (dk/dε)_eff=Ωk relating the effective work hardening with the workpiece yield stress times a factor Ω, named stability function, that is a function of the rolling process parameters and stress-strain path. The second step it consists in the microscopic work hardening evaluation subtracting, from the effective work hardening, the plastic hardening/softening under perfect plastic assumption. The novel incremental plasticity approach could be applied to many metallurgical applications such as strip microstructure evolution during hot rolling process, to design optimized rolling schedule, to investigate on strip failure in rolling process by plastic stability/instability analysis and finally to realize a smart rolling sensor. KEYWORDS: Effective work hardening, incremental plasticity, stress-strain path, plastic stability, smart rolling.

Thomas Haschke, SMS group, Germany

Co-Author:
Thorsten Huge, SMS group
Michael Lipowski, SMS group
Christian Mengel, SMS group
Bettina Fischer, IMS Messsysteme GmbH
Horst Krauthäuser, IMS Messsysteme GmbH
Ingo Leckel, Salzgitter Flachstahl GmbH

Abstract:
An excellent width performance is indispensable to enable stable, efficient and sustainable production. Since width control in hot rolling mills is almost exclusively possible in the roughing mill, the width measurement in the roughing mill is of particular importance. Radar technology has proven to be suitable for such applications due to its robustness and precision even under the harsh environmental conditions including steam, dust and high temperatures. In the hot strip mill in Salzgitter, a radar width measurement is installed between the slab sizing press and the roughing mill immediately upstream to the edger and used for several tasks in order to optimize the transfer bar and therewith finally the finishing strip width: First, the width error coming from the slab sizing press is calculated by comparing the slab width measured in the radar gauge and the setup width of the press. A possible width error is corrected by an adaption model in the pass schedule model PSC® and given as an additional offset to the slab sizing press for the subsequent slab. Second, the measured strip width is considered in the PSC® within the recalculations of the reversing passes in the roughing mill. Based on the reliable measurements, updated width information are used to calculate new setups for the next subsequent combinations of width- and thickness-reductions in the roughing mill. Third, the information from the radar gauge are used in the level 1 control system for plausibility checks in order to optimize the tracking accuracy and therewith the short stroke control at the slab ends in the edger. With these measures, the width errors and above all the excess width at the strip end could be significantly reduced. Further improvements can be achieved by considering the measurements in the short stroke control to avoid necking respectively excess widths.

Michael Breuer, SMS group, Germany

Co-Author:
Georg Padberg, SMS group

Abstract:
The flat product market increasingly demands hot strip for direct further processing. Thin hot strip is applied in many industries. In general: all cold rolling applications that do not require heavy deep drawing operations and a high surface quality can be replaced by thin hot strip. Plant owners may optimize or reduce the process steps. Cold rolling passes and/or intermediate annealing can be omitted or even be canceled completely, resulting in increased profitability and energy savings. There are special hot mill concepts on the market, which focus specifically on the thin strip demand. However, they come with a drastically reduced product range and weakened flexibility to react on process disturbances. The process control in a hot strip mill has to face special challenges arising with the production of strip with thicknesses of less than 2 millimeters. Some of the typical challenges that occur during thin-strip rolling are: • Ripped strip end • Pinching caused by unflatness • Steering control • Increased roll wear • Save coiling • Speed limitations These challenges may cause a deterioration of the yield due to increased off-gauge lengths and the number of cobbled coils. SMS group is aware of these challenges and offers customers a “toolbox” to improve the behavior of the hot strip mill when “going thin”. The “toolbox” consists of mechanical and automation equipment and software. Beside fast mechanical actuators, a number of strip guiding systems are part of the toolbox. The strip steering control module has an important task in achieving a straight transfer bar and avoiding cobbles and ripped strip ends. Also, the operator is released from the leveling task and can focus on the rolling process. Beside strip steering control, the paper will give insights into other related topics and their impact on the production of thin gauges. Some operational results will be presented as well.

Jakob Schwarzmann, IMS Messsysteme GmbH, Germany

Co-Author:
Horst Krauthäuser, IMS Messsysteme GmbH

Abstract:
Cold rolled steel plate contains a variety of defects. Some optically visible defects cannot be reliably classified by OIS due to missing depth information. Defects not protruding trough the material surface, like non-metallic inclusions (NMI), are invisible for optical inspection systems and can disturb further processing. Therefore, a complete online inspection for hidden defect detection is required to ensure proper material quality, prevent disturbances during further processing and enable defect root cause identification by augmenting OIS data. A proven detection method for hidden defects in ferromagnetic materials is magnetic flux leakage, which is widely used as magnetic powder testing. IMS extended this method to moving material by developing an online MFL inspection system using GMR magnetic field sensors which generate a complete magnetic image of the strip (inclusion detection System – IDS). The generated images are processed by an advanced processing software which reliably finds defects in the background noise and enables their classification based on configurable features. The position of the magnetic field sensors is automatically adapted to varying material thickness. Optical and capacitive sensors permanently check the strip for folds and monitor the gap between the sensors and the material. In case of line disturbances, a rapid retraction of the sensors is contrived by spindle and pneumatic drives. The latter also allows to move the system out of line for maintenance. All relevant elements are liquid-tempered for operation under various ambient conditions. While initially being developed for thin cold rolled plate, tests have shown the suitability of the IDS for usage on thicker material. A promising sensitivity was achieved for thicknesses of up to 2 mm, opening up new applications like automotive cold rolled plate. This paper and presentation show the concept and implementation of this inspection method as well as results for various types of defects and materials.

Ahmet Mithat Avsar, İsdemir, Turkey

Abstract:
The innovative technology and sophisticated control systems for hot rolling mills has opened up new possibilities for designing and engineering of efficient systems and overcome common problems specific to processes. Performance of rolling mills and subsequent processes such as coil box equipment are key to successful production in today’s World of steel manufacturing. In the Coilbox, the transfer bar which is coming out of the roughing mill is coiled. Unwinding is effected in the reverse direction. The tail end of the bar runs first into the finishing mill. The Coil Box Stabilizer 1 is installed on the Cradle Roll 1A/1B that guide the transfer bar into the Coil Box. Stabilizers consist of stabilizer plate and guide rods, and are used for centering the coil position. The stabilizers are operated by means of hydraulic cylinders with position transducer to ensure the stability of a coil during coiling and uncoiling operation. In this paper, When the transfer bar starts coiling to the defined diameter, the stabilizer moves to short stroke position – set point is function of slab width, offset and short stroke value with position control. The control mode is switched to force control when the guide plate comes into contact with the transfer bar. But this process can lead to cobble situation especially tail end starts to open… This paper introduces In this paper …tail ..problem is examined Succesfully applied solution is presented… by improving working principle of stabilizers… intelligent mechanism is adapted o existing working modes… intelligent force control first by sensing if … occurs then prevenitive measure is taken by switching the mode from position control to force control if force level exceeds certain limit .. and then.. stability of tail of transfer bar mqaintained… thus preventing transfer bar to stuck in down stream equipments such as stabilizer 2, FM Stands

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

Abstract:
The robotic workstation allows to cut, remove and break the steel strap used in the binding process of the cut coils entering the ERW Tube Mill. A 3D computer vision system can identify with high precision the position of the strap and the start of the coil to identify the best cutting position in order to avoid any damage of the external surface of the coil. This automated solution allows complete operator safety in the production process.

Paula Reimer, Linz Center of Mechatronics GmbH, Austria

Co-Author:
Jagoba Lekue, Linz Center of Mechatronics GmbH
Erik Parteder, voestalpine Grobblech GmbH
Andreas W. Nemetz, Johannes Kepler University
Thomas Kaltenbrunner, voestalpine Grobblech GmbH
Bodo Heise, voestalpine Grobblech GmbH
Stefan Falkner, voestalpine Grobblech GmbH
Thomas Gross, Linz Center of Mechatronics GmbH
Rupert Egger, voestalpine Grobblech GmbH
Klaus Zeman, Johannes Kepler University

Abstract:
As accuracy requirements for tolerances of heavy plates are continually increasing, precisely tuned process control is indispensable. The aim of this work is to characterize the relevant thermomechanical effects on a heavy plate mill depending on the pass configuration. This was done by performing a parametric study with a high-resolution 2D Finite Element (FE) offline model of the roll gap. Particular attention was paid to thermomechanical coupling. As a cross-section of the heavy plate moves through the roll gap, its temperature distribution is influenced by the heat flow within the plate, the heat exchanged with the work rolls, the heat generated by plastic deformation as well as frictional dissipation at the interface between work rolls and heavy plate. The implemented FE model considers the described effects as well as the elastic flattening of the work rolls. It also contains temperature dependent material behavior, identified by laboratory measurements, and a limit for the transmissible frictional shear stresses as a function of the current yield stress of the rolled material at its contacting surface. The calibration of non-measurable parameters like heat transfer coefficients and friction coefficients was accomplished based on a broad spectrum of measurement data extracted from the process. By incorporating all relevant physical phenomena, the employed FE model represents a benchmark for the prediction of the roll separating force, the roll torque, and the temperature distribution over the plate thickness. The results of the parametric study indicate which thermodynamic effects dominate in which area of the parameter range. Furthermore, they help to improve the overall comprehension of the system and open the door to the condensation of the model to a reduced online model that allows the calculation of one pass within milliseconds without substantial loss of accuracy.

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

Abstract:
A rolling mill plant basically consists of reheating furnaces, rolling mill and accessory devices. The economic efficiency of metal rolling processes is strongly correlated to the quality level of the end-rolled products. Rolling of flat steel products is a complex process where the quality of the product is influenced by a range of factors such as incoming material, mechanical and electrical equipment, operating parameters and automation and control strategies etc. The significant quality parameters are: - material thickness, - material shape and surface, - homogeneity of stress distribution. Product quality can only be effectively optimized if the mechanical, electrical and instrumentation equipment, as well as the control strategy solution combined, work together.

Chitoshi Mochizuki, Primetals Technologies Japan, Japan

Co-Author:
Shinya Kanemori, Mitsubishi Heavy Industries, Ltd.
Gerard Goessens, Tata Steel IJmuiden, B.V.

Abstract:
" Commonly in a commercial hot rolling mill the operator monitors the rolling situation at the mill pulpit. If the operator recognizes some abnormal rolling situation, he/she will intervene by adjusting the appropriate rolling mill actuator. Recognizing abnormal rolling situations and adjusting the actuators depends on the operator skill level. If instead a computer can detect the abnormal rolling situation and can automatically and appropriately correct the situation based on specific controlling logic, it is thought that the rolled strip quality could become better and more stable rolling could be achieved. For this purpose two kinds of rolling condition monitoring systems have been developed using image processing technology and those systems have been verified offline. Those systems are “strip shape trend monitoring system” and “strip pinching detection system”. The former has been achieved by utilizing the shape change of a reflecting light area on the strip, and the later has been achieved by utilizing the difference of the strip surface color between normal and abnormal rolling situation. The final target of this rolling condition monitoring system is to realize automatic intervention such as leveling or bending corrections by computer instead of manual intervention by operator. However, in the case of that the automatic intervention by computer is undesired, only manual intervention guidance indication for operators can be also selected. It enables detecting and notifying operators on critical conditions of rolling processes to increase quality and improve the productivity. With this paper we present an approach on how digital assistants can be deployed for industrial applications, especially hot rolling."

Simon Hain, Primetals Technologies Germany, Germany

Co-Author:
Andreas Maierhofer, Primetals Technologies Germany

Abstract:
"Silicon steel grade sheets are essential to e-mobility. The material is hard, thin, and brittle, especially at the edges. With thinner gauges, magnetic losses are reduced, but the filling factor increases with more sheets. Therefore, the permeability and magnetization diminish. Contactless flatness measurement is beneficial for reducing the risk of strip breaks from edge cracks and to control flatness also at lower rolling speed. Additionally, it helps to get faster into the tolerances at the strip head since the response time due to the measuring principle is constant. Compared with flatness rolls which have to turn to get measurement readings the contactless principle allows to measure independently from a rotating roll or strip movement. Primetals Technologies has developed contactless flatness measurement consisting of actuators to oscillate the strip and eddy current sensors to detect inhomogeneities of the internal tensions. Since there is no contact with the strip, surface quality is maintained, and no wear occurs. Because of the straight forward construction, compared to a flatness roll, a maintenance can be done on site by the service personal in short time."

Alexander Kofler, SMS group, Germany

Co-Author:
Klaus Pronold, SMS group
Christian Mengel, SMS group
Guido Eichert, EMG Automation GmbH

Abstract:
The target of the centerline control is to eliminate the need of manual interventions for steering of the hot strip in a finishing mill. The new system works based on the highly accurate and reliable HotCAM measuring system. It measures the lateral hot strip position between the finishing mill stands. The highly sophisticated steering control philosophy will be explained. Further, we present first results on improved head, body and tail rolling stability, productivity increase, impact on reduced work roll damages and therefore unexpected roll changes and improved strip surface defects of this latest installation. The results will show a tremendous improvement by this technology. These results will be presented as well as future steps to ultimately eliminate permanent human interventions for hot sheet rolling paving the path towards lights-out operation.

Kyoung Sik Woo, Hyundai Steel Co. , Korea, Republic of

Co-Author:
Seung Min Hur, Hyundai Steel Co.

Abstract:
Following the recent trend of weight reduction in car industry, producing high quality cold-rolled UHSS(Ultra High-Strength Steel) strip becomes important. Strip breakage in Tandem Cold Mill(TCM) is one of the biggest problems in cold rolling. When producing UHSS, strip breakage occurs more frequently. When a plate break occurs, the line stops. And productivity decreases. And safety issues can also arise during maintenance work. So we need methods to prevent strip breakage. Most of the strip breakage in TCM occurs near the weld-point between the coils. In general, strip breakage is caused by over rolling force at the weld-point. So in this paper, we propose Soft Rolling Control near the weld-point between the coils. Soft Rolling means a rolling method that makes the weld-point thicker. We propose two methods to makes the weld-point thicker. They are a method using the predicted rolling force and a method using the mass flow theory.

Jörn Sieghart, SMS group, Germany

Co-Author:
Klaus Pronold, SMS group
Wolfgang Hofer, SMS group
Rachid Barkouta, SMS group

Abstract:
X-Pact® Superior Control, as an integrated technological solution that comprises artificial intelligence and expert systems, actively provides optimized rolling strategies for level 1 and level 2 systems and implements the presets in real time for strip changes. The objective is thus to create a technologically self-optimizing plant that continuously enhances its product quality over its whole life cycle. The advantage of this step beyond the limits of the level 1 and level 2 systems is that interlinked and separately runnable structures can be mapped. In concrete terms, this means that the automation system does not require a fixed differentiation between the level 1 and level 2 systems. Both systems work in a closely connected and coordinated manner, thereby opening up a multitude of new technological possibilities. The paper describes, how an expert system, developed as part of X-Pact® Superior Control, automatically calculates the optimum strategy for all product changes, i.e. the optimum combined method of operation from the technology clusters such as flatness, thickness, etc. This look back at the past can now be done as often as needed based on mass data. The next step, therefore, is to supply digital AI systems to provide a forecast for the optimal product change strategy. As soon as the artificial intelligence provides a sufficient hit rate in its prediction, it generates added value in the form of an improved off-gauge length for strip flatness and thickness and increased product change stability. This is because the proposed strategy from the digital AI system can directly be coupled to the control of the technology clusters of level 1 and level 2 systems. These AI systems provide optimized strategies for level 1 and level 2 systems and implement the presets in real time for strip changes.

Matt Anderson, Primetals Technologies US, United States

Co-Author:
Thomas Wojtkowski, Primetals Technologies US
Martin Thiemar, Primetals Technologies US
Peter Osgood, Primetals Technologies US

Abstract:
Optimizing the efficiency and availability of MORGOIL® bearings directly impacts rolling mill productivity and quality. Management is aware of the significant benefits associated with a well-run bearing monitoring program, however few companies have the resources or expertise to implement “predictive technologies” on their own. These systems are the basis for preventing problems and properly planning maintenance, thus achieving long-term mill success. Using condition monitoring technologies, Primetals Technologies has developed a suite of Predictive Maintenance and Monitoring strategies to monitor and assess MORGOIL® backup bearing operations to reduce unscheduled down time and to increase productivity. These techniques utilize a full complement of sensor technologies connected to a Human Machine Interface (HMI) to capture and interpret vital information from operating MORGOIL® bearings. The computer interface provides mill operators a ‘real time’ warning if bearing operating parameters exceed safe limits. Additionally, the system ensures that there is adequate oil flow to the bearings before rolling is started. These systems typically also fully monitor the lubrication system. Examples of existing systems built into new Primetals Technologies hot mills will be shown. Similar systems can be custom implemented in existing mills on an incremental basis depending on existing mill systems. A well implemented and managed MORGOIL® Predictive & Monitoring System, is the most effective method of managing risk, increasing reliability, and ensuring the best possible return on mill operation.