Influence of strain induced grain boundary migration on grain growth of 300M during static and meta-dynamic recrystallization

The microstructural evolution of 300M steel during the isothermal treatment between deformations is studied. Firstly, interrupt compressions of 300M steel at temperature of 1273K and strain rate of 0.01s-1 are conducted to figure out the kinetics of static recrystallization (SRX) and meta-dynamic recrystallization (MDRX), subsequently an in situ heat treatment experiment is designed to measure the amount of strain induced grain boundary migration (SIGBM) and compared with interrupt compressions. The results show that MDRX is verified to have a lower nucleation rate than SRX in 300M steel. In addition, SIGBMs mainly appear at the triple junctions, and the amount of SIGBMs during SRX and MDRX both reach the maximum value between the steady state time and the time of 50% fraction softening. Finally, the grain growth driven by SIGBMs dominates the subsequent isothermal treatment after the new round of nucleation induced by MDRX and SRX.