Constitutive modeling of dynamic recrystallization behavior and processing map of Cr5 steel

The hot deformation behaviors of Cr5 steel were investigated. The hot compression tests were conducted in the temperature range of 900−1150 °C under strain rates of 0.01, 0.1 and 1 s−1. The constitutive equation and material constants (Q, n, α lnA) are obtained according to the hyperbolic sine function and Zener-Hollomon parameter. Besides, dynamic recrystallization (DRX) grain size model and critical strain model are acquired. The processing maps with the strain of 0.1, 0.3 and 0.5 are obtained on the basis of dynamic materials model. It has been observed that DRX occurs at high temperature and low strain rate. According to the processing map, the safety region exists in the temperature range of 920−1150 °C with strain rate of 0.01−0.20 s−1.