Experiment and simulation of static softening behavior of alloyed steel during round bar hot rolling

Abstract Static softening is a crucial mechanism during the hot rolling of steel to relax residual stress and strain, refine microstructure, and improve mechanical properties. In this study, double hit tests with varying temperature, strain rate, interpass time, and pre-strains were performed using a Gleeble machine to investigate static softening behavior. Based on experimental results, a kinetic model of static softening was developed to represent interpass softening behavior during hot rolling. An explicit static softening model was implemented as a subroutine into a three-dimensional finite element model of round bar hot rolling and static softening was simulated. Results show that static softening occurs quickly at the beginning of the interpass time and then slows down. Also, the effects of temperature and rolling speed on static softening were simulated and the results show that temperature has a more significant influence on static softening than rolling speed.