Effect of electropulsing and annealing treatment on microstructure and mechanical properties of 316L stainless steel

Abstract

Considering the consumption of time and energy for the traditional heat treatment process, a new heat treatment method with high speed and low energy consumption has always been the direction of researchers. The microstructure and mechanical properties of engineering 316L stainless steel were measured under electropulsing treatment within 400 ns and annealing treatment for 2 h. Compared with the original cold-rolled state, it was found that the yield strength after 3.8 × 103 A/mm2 electropulsing treatment was reduced by 26.2% and that after 800 °C heat treatment was reduced by 27.7%. The nucleation after electropulsing treatment is mainly concentrated at one end of the lamellar grain and finally grows into the square or rhombic grain with an average grain size of 1.5 µm. After annealing, the nucleation is mainly concentrated at the grain boundaries of the lamellae and finally grows into equiaxed grains with an average grain size of 1.8 µm. Under the action of electronic wind, the recrystallization nucleation after electropulsing is mainly dominated by the mechanism of subgrain nucleation and growth. However, under the action of a uniform thermal field, the recrystallization nucleation after annealing is mainly based on the grain boundary bow-out mechanism.