Implementation of Experimental Static Recrystallization of High Strength Steel into Computational Simulation of Multi-pass Slab Hot Rolling

Microstructural changes and softening due to static recrystallization have a critical influence on thermo-mechanical behavior of high strength steels during industrial multi-pass hot rolling. Numerical simulation using finite element analysis (FEA) can be used to accurately predict the softening behavior during the hot rolling process. Therefore, the implementation of an experimentally defined static recrystallization model into FEA is necessary to get realistic simulation prediction. In this study, the extent of softening during static recrystallization in Si and Mn alloyed high strength steel was measured using double hit tests. A Gleeble (TM) thermo-mechanical simulator was used to perform the double hit tests with variations in temperature, strain rate, and interpass time. The kinetics of static recrystallization was developed based on the experimental results and implemented into a finite element model of a multi-pass plate hot rolling process using explicit subroutines. Three different modeling approaches were implemented in Abaqus to predict the fraction of static recrystallization and softening during multi-pass hot rolling. Simulation results showed that the fraction of recrystallization significantly depends on the extent of thickness reduction during rolling at a typical industrial multi-pass schedule. Additionally, an increase in temperature greatly increased the fraction of recrystallization and static softening. The suggested approach could be used for the optimization of the hot rolling process for Si and Mn alloyed high strength steels.