The metadynamic recrystallization(MDRX)model is established,and the coefficients determined by multiple linear regression analysis are used to describe the microstructure evolution of SA508Gr.4N steel.The effects of compression temperature of 950–1150℃,strain rate of 0.001–0.1 s^(-1),pre-strain of 0.3–0.6,initial austenite grain size(IAGS)of 136–552 lm,and interval time of 1–300 s on the MDRX kinetics and microstructure evolution were analyzed,using twopass compression test method on Gleeble thermo-mechanical simulator.The results show that MDRX kinetics and austenite grain size are strongly dependent on compression temperature and strain rate,MDRX volume fraction increases with increasing compression temperature and strain rate,and the grain size decreases with increasing strain rate and decreasing compression temperature,while less affected by the pre-strain and IAGS.Meanwhile,the values predicted using MDRX model and the ones calculated from experiment are compared,and the results show that the proposed model can give a reasonable estimate of MDRX behavior for SA508Gr.4N steel.
