Hot deformation behavior of austenitic stainless steel for a wide range of initial grain size

The hot deformation behavior of AISI 304L stainless steel with a wide range of initial grain size was studied using hot compression tests corresponding to the temperature range of 900–1100 °C under strain rates ranging from 0.001 to 1 s−1. All flow curves showed typical single peak dynamic recrystallization (DRX) behavior. By increasing the initial grain size, the range of flow stress became tighter and the characteristic DRX peak tended to vanish. The application of constitutive equations to determine the hot working constants of this material was critically discussed and the values of 0.010 and 392 kJ/mol were determined for stress multiplier and deformation activation energy, respectively. It was also found that the conventional value of 0.012 for stress multiplier and the calculated activation energy based on the chemical composition (398 kJ/mol in this case) are applicable in hot deformation studies of AISI 304 stainless steel. The normalized critical stress and strain for initiation of DRX were found to be 0.92 and 0.53, respectively. These values were within the reported ranges for steels.