Microstructural Evolution during Homogenization and Hot Deformation for As‐Cast H13 Steel

The hot compression experiments are accomplished to investigate the microstructural evolution of as‐cast H13 steel during homogenization treatment and hot deformation. At a certain homogenization temperature, the dynamic recrystallization (DRX) volume fraction increases with increasing strain and deformation temperature and decreasing strain rate. However, the DRX is also easy to proceed at a high strain rate of 5 s −1 due to the high shear stress. The recrystallization is inhibited in a dendrite segregation region. The residual dendrite segregation left after homogenization treatment will improve the recrystallization nucleation rate during the subsequent deformation. The recrystallization grains preferentially nucleate in the dendrite region, and the grain growth is inhibited by the dendrite segregation. The partial homogenization before deformation is beneficial to achieve the fine microstructure.