Influence of microstructure on the frictional behavior of 316LN austenitic stainless steel under cryogenic condition

Traditional austenitic stainless steels (ASS) face difficulties in safely operating under low-temperature sliding wear conditions due to their relatively low strength and hardness. To address this issue, this study investigates 316LN ASS, designing and preparing non-recrystallized (NG), heterogeneous (HS), and fully recrystallized (CG) structures through rolling and annealing processes. The effect of structure on the tribological behavior and wear mechanisms of 316LN ASS was analyzed. The results indicate that, unlike NG and CG structures, the HS structure exhibits the lowest coefficient of friction (CoF) due to the reduction of wear debris particles, which decreases direct contact between the wear surface and the counterface. Compared to NG and HS structures, the CG structure exhibits the lowest wear rate. This is attributed to its low stacking fault energy, which induces martensitic transformation, and the formation of a nanostructured/ultrafine-grain hardened layer on the worn surface, effectively preventing crack propagation and significantly enhancing wear resistance. The HS structure also undergoes martensitic transformation and forms a similar surface hardened layer during wear, but the wear debris generated during the process acts as third-body abrasives, further exacerbating the wear and reducing wear resistance. In addition, due to its excellent low-temperature plastic deformation ability, the CG structure exhibits slight abrasive wear characteristics during the wear process.