Effect of post-treatments on the fatigue behaviour of 316L stainless steel manufactured by laser powder bed fusion

This paper investigates the influence of post treatments on the fatigue properties of 316L stainless steel produced by laser powder bed fusion. Miniaturised fatigue samples are built in vertical orientation with optimised process conditions to result in very low porosities and minimal scatter in results. Fatigue performance is evaluated for two different material conditions: as-built and stress-relieved, at a nominal load ratio of -1. Furthermore, the samples are tested with and without surface machining. A thorough microstructural and fractographic analysis is performed to evaluate the impact of the main fatigue influencing factors. The results show that the fatigue behaviour of machined samples with and without stress relief heat treatment exceeds that of conventionally manufactured 316L.