Toward a 2D/3D Finite‐Element–Based Digital Shadow for the Approximation of Metrologically Inaccessible Dynamic Fields of State Variables during Heavy Plate Rolling

Abstract

Heavy plates are products of global economic relevance. Due to the high requirements for this semifinished product, the trend in heavy plate processing is toward providing ever higher quality steels that, for instance, combine a predefined yield point, good weldability, and, at the same time, predefined toughness properties. Unprecedented quality requirements in steel processing can only be met if technologically relevant parameters, such as temperature, are guaranteed to be kept within a narrow tolerance range during the hotrolling process, one of the most decisive steps within the production chain for heavy plates. Within the heavy plate hot-rolling process, often performed in a reversing four-high mill stand consisting of a pair of work rolls and a pair of backup rolls, various production steps like rolling passes, descaling sequences, and cooling periods, determine the plate's temperature evolution. [1] In parallel, temperature evolution affects the microstructure and, thus, associated physical properties of the final product, such as hardness and toughness. [2] It is, therefore, of utmost importance to consider the evolution of the temperature field inside the heavy plate as a specification when planning the entire process that reaches from the slab's exit from the furnace to the last pass.All in all, the production steps of hot rolling govern the plate temperature in two fundamentally different scenarios: sufficiently far from the roll bite, the plate temperature decreases moderately through air cooling or abruptly on the surface of the plate through contact with water which is applied locally in the form of high-pressure jets provided by a water descaling unit. Inside the roll bite, the plastic deformation is accompanied by heat generation inside the plate, and simultaneously the contacting cooler work rolls reduce the temperature at its surfaces. These and other thermomechanical effects can hardly be measured, which is the reason why models are utilized for better insight. As digital transformation has become a significant innovation driver, a digital representation of the process in the form of an integrated digital model, digital shadow, or digital twin has to cover these potentially interfering thermomechanical aspects. [3,4] Modeling and simulation have been integral to the research and development of rolling processes for decades. An incomplete but representative selection of milestones, in chronological order, is intended to outline the road to comprehensive modeling approaches available today: The journey started with basic

Modular Finite Element Modeling of Heavy Plate Rolling Processes Using Customized Model Reduction Approaches

“…From then on, the rolling stock is no longer referred to as a slab but as a plate. After the plate has left the roll stand, it is taken over again by the roller table, and the process becomes, to a good approximation, purely thermal again [24]. From this consideration, the class's first essential attribute ("load case attribute") follows to define the type of load case (thermal/thermo-mechanical).…”

“…Afterwards, the plate is turned back to its original orientation. Suppose the rolling process includes no rotations; a symmetric model could be used to simulate the process [24]. Then, in the sense of model reduction, only the right or the left half of the system is modeled.…”

“…A holistic model that covers the efficient, application-oriented simulation of the thermo-physical behavior of the plate along whole rolling schedules has not been detected. A 3D modular FE approach for the purpose of tracking the fillet of a heavy plate throughout a longitudinal rolling process consisting of several passes was published in 2023 [24]. The benefit of the modular modeling strategy shown in [24] is its ability to investigate the temperature distribution across the plate's width direction.…”

“…A 3D modular FE approach for the purpose of tracking the fillet of a heavy plate throughout a longitudinal rolling process consisting of several passes was published in 2023 [24]. The benefit of the modular modeling strategy shown in [24] is its ability to investigate the temperature distribution across the plate's width direction.…”

“…The model introduced in the present article is an advancement of this modular modeling strategy [24]. Integrating new routines into the model allows for the comprehensive simulation of a heavy plate rolling process, including both longitudinal and spreading passes.…”