Prediction of Critical Conditions for Dynamic Recrystallization in 316LN Austenitic Steel

Hot compression experiments conducted on a Gleeble-3500 thermo-mechanical simulator and metallographic observation tests were employed to study the critical conditions of dynamic recrystallization (DRX) of 316LN austenitic stainless steel. The true stress-true strain curves of 316LN were obtained at deformation temperatures ranging from 900 °C to 1200 °C and strain rates ranging from 0. 001 s−1 to 10 s−1 . Based on the above tests, the critical conditions of DRX were determined and compared with those obtained from work-hardening theory and the Cingara-McQueen flow stress model. Furthermore, the microstructure was observed to validate the calculated results. The ratio of critical strain to peak strain (ɛc/ɛp) for 316LN was determined, and the quantitative relationship between the critical strain and the deformation parameters of 316LN was elucidated. The results demonstrated that the onset of DRX corresponds to the constant normalized strain hardening rate (Γ), namely, the critical strain hardening rate Γc for 316LN is equal to 0. 65.