Tong Zhu, Marek Smaga, Stefan Thielen, H. Hotz, Benjamin Kirsch, Jan C. Aurich, Bernd Sauer, Oliver Koch, Tilmann Beck

• Cryogenic turning of metastable austenitic stainless steels can improve wear resistance of the resulting surface due to the phase transformation of γ-austenite into α’- and/or ϵ-martensite in the near surface layer. By using a cryogenic two-step turning process, the amount of deformation-induced α’-martensite in the subsurface regime can be further increased. To determine the influence of the implemented and optimized two-step turning strategy on the tribological properties of countersurfaces for radial shaft seals, an evaluation of wear behavior of the shaft seal countersurface as well as microstructural analyses in subsurface regime is presented and compared to the cryogenic single step turning process. The results show that not only the integral phase transformation in the overall subsurface region, but also the local phase distribution plays an important role when it comes to the surface performance in tribological applications.