Dynamic Recrystallization under Hot Deformation of a PH Stainless Steel

Dynamic recrystallization, DRX, behaviour of a precipitation hardened, PH, stainless steel was studied in connection with microstructural developments in a compression test. The experimental results showed that the dominant mechanism of softening is DRX, but at high strain rates and low temperatures, ie, high Zener-Holman parameter, Z, work hardening and dynamic recovery, DRV, produced a pancked structure. When Z values decreased, the flow curves displayed DRX in two ways: single peak behavior observed at low Z values and multiple peak behavior at the lowest ones. In addition, the peak strain, εp, necessary for DRX is also determined as a function of peak stress, sp, and Z. According to the observed and calculated data, at low sp values, εp is directly proportional to sp, while in higher amounts, εp rarely depends on it. Besides, εp expotenentially depends on Z.