The hot deformation behavior of a 17-4 PH stainless steel was investigated by compression test. A step by step procedure for data analysis in hot compression test was given. Many samples exhibited typical single-peak DRX behavior. However, at low Zener-Hollomon parameter (Z), this material showed a new dynamic recrystallization (DRX) flow behavior, namely Multiple Transient Steady State (MTSS). Two types of constitutive equations were used to study the hot deformation behavior: (1) a conventional method of finding apparent materials constants, and (2) a physically-based approach which accounts the dependence of Young’s modulus and self-diffusion activation energy on temperature. Both methods were critically discussed and some modifications and easy-to-apply methods were also introduced. It was found that when the deformation mechanism is controlled by the glide and climb of dislocations, an exponent of 5 can be set in the A simple constitutive equation was developed in this work for prediction of flow curves. This technique and the artificial neural network (ANN) were found to be suitable for the modeling and prediction of flow curves. However, the hyperbolic sine equation with strain-dependent constants was found to be inappropriate for this purpose. The Avrami analysis was successfully used for extrapolation of flow curves. The DRX rate parameter (DRXRP) was proposed in this work for analyzing the kinetics of DRX. Keywords: 17-4 PH stainless steel, Hot deformation, Dynamic recrystallization, Constitutive equations, Flow stress.
