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 ltr" Keywords: 17-4 PH stainless steel, Hot deformation, Dynamic recrystallization, Constitutive equations, Flow stress.
