Effects of Thermal Compression Parameters on Dynamic Recrystallization Behavior of M50NiL Bearing Steel

Effects of deformation temperature, deformation amount and strain rate on dynamic recrystallization (DRX) behavior of M50NiL steel were investigated based on thermal compression simulation experiments. Results show that no DRX occurs if the deformation temperature is below 900℃. When the deformation temperature increases to 1 000℃, DRX is not enough and mixed grains microstructure is formed. When the deformation temperature increases to 1 100℃, DRX is fully completed, and the uniform fine equiaxed grains are obtained. However, if the deformation temperature reaches to 1 200℃, the grain tends to coarsen up. DRX nucleation rate increases with the increase of deformation amount under the conditions of deformation temperature of 1 100℃ and strain rate of 10 s^-1; DRX is finished when the deformation amount is up to 60%. DRX nucleation increases with the increase of the strain rate when the deformation temperature and deformation amount are 1 100℃ and 60%, respectively; furthermore, when the strain rate increases to 20 s^-1, DRX is fully completed, and fine and uniformly distributed equiaxed grains are obtained.