Modelling Microstructure Evolution During Hot Rolling: A Practical Expert System

摘要

Microstructure evolution during hot rolling determines to a large degree the mechanical properties that the hot rolled steel will achieve when tested at room temperature. Hot rolling is a complex process involving several passes or deformations at different temperatures, strains, strain rates and delay times, all of which influence how the austenite microstructure evolves. During phase transformation from austenite to ferrite, the strain accumulated by austenite prior to transformation and the cooling rate define the type and size of the final microstructure when the steel is returned to room temperature. Therefore, a better understanding of how microstructure can evolve during hot rolling is critical in the sense of being able to control the process and design schedules which are appropriate to yield an optimum product.Modelling of microstructure evolution is presented here as a practical expert tool to be used in the design and improvement of hot rolling schedules. First, the fundamentals of the model are introduced. Then, case studies are described to illustrate how to use the model from the perspective of schedule design and schedule improvements. Finally, "what if" scenarios are presented and discussed aiming at increasing familiarity of end users with the model.