Grain growth kinetics and hardness empirical model of 253 MA austenitic stainless steel after multi-pass cold rolling

This study investigated changes in the average grain size and hardness values of 253 MA austenitic stainless steel (ASS) and determined the grain growth kinetics as well as a hardness empirical model. A 35% multi-pass cold rolling process was employed to reduce the thickness of a 253 MA austenitic stainless steel pipe. Then, the rolled steel was annealed at 1100 °C for various soaking times of 0, 900, 1800, 2700, and 3600 s in a tubular furnace under a hydrogen atmosphere, followed by quenching to room temperature in the cool zone of the furnace. Then, micro-Vickers hardness measurements were done using a force of 0.3 N and the grain size changes were observed. A line intercept method was applied to measure the change of the 253 MA austenitic grain size. The results show that the average grain size of 253 MA ASS (austenitic stainless steel) increased with soaking time, while the hardness values decreased. Additionally, an equation modeling the predicted grain growth and hardness values was obtained.