Investigation on metadynamic recrystallization behavior in SA508-Ш steel during hot deformation

The metadynamic recrystallization (MDRX) behavior of SA508-Ш steel was investigated by isothermal double-hit hot compression tests at forming temperatures of 950-1250 °C, strain rates of 0.001-0.1 s−1 and the inter-stage delay time of 1-300 s. Experimental results show that the effects of forming temperature and the strain rate are significant, while the pre-strain and initial grain size are less on metadynamic recrystallization behavior of SA508-Ш steel. Based on the experimental results, the kinetic equations and the grain size model for metadynamic recrystallization of SA508-Ш steel were established. Comparisons between the experimental and predicted results were carried out. The predicted results agree well with the experimental data, which indicates that the proposed kinetic equations can give a reasonable estimation of the softening behavior for this steel. Furthermore, by implementing the established kinetics and microstructural evolution equations of MDRX into commercial FE software, the hot forging process of SA508-Ш steel can be designed and optimized through numerical simulation.