Dynamic Recrystallization Behaviors and Kinetic Model of Austenitic Stainless Steel

High-temperature compression tests with multiple parameters coupling, including deformation temperatures （1223, 1323, 1423, 1523 K） and strain rates （0.01, 0.1, 1.0, 10.0 s⁻¹）, were conducted, the evolution law of dynamic softening behavior of 310S stainless steel was studied, the mathematical model of critical strain for dynamic recrystallization based on dislocation annihilation mechanism was established to determine the initiation time of dynamic recrystallization, and the recrystallization fraction prediction model considering strain distribution effect was constructed to characterize the evolution of dynamic softening behavior. The results show that the flow curves at different deformation temperatures and strain rates all presented typical three-stage evolution characteristics, and the core dynamic softening mechanism was dynamic recrystallization. When the deformation temperature was relatively low （1223-1323 K）, the microstructure showed incomplete recrystallization characteristics, with a bimodal distribution of coarse parent phase grains and dispersed fine grains, and the proportion of parent phase grains was relatively high at relatively high strain rates. When the deformation temperature was relatively high （1423-1523 K）, the microstructure showed or approached complete recrystallization. The dynamic recrystallization volume fraction obtained from the constructed critical strain model for dynamic recrystallization and the dynamic recrystallization volume fraction prediction model was positively correlated with the deformation temperature and negatively correlated with the strain rate, which was consistent with the experimental results and coul effectively describe the dynamic recrystallization kinetics characteristics of 310S stainless steel during hot deformation.