The influence of applied load, sliding velocity and martensitic transformation on the unlubricated sliding wear of austenitic stainless steels

In this work, the sliding wear of AISI 304 and AISI 316 austenitic stainless steels was studied as a function of applied load (from 6 to 20 N) and tangential velocity (from 0.07 to 0.81 m s−1). Wear experiments were conducted in a commercial pin-on-disc equipment and were designed with response surface methodology. Worn surfaces and wear debris were analyzed through scanning electron microscopy, X-ray diffraction, Mössbauer spectroscopy, surface temperature and instrumented indentation. Results indicated plasticity-dominated wear (metallic particle oxidation, adhesive wear and mixed wear) as the sliding wear mechanisms. The wear rate was dependent on the interaction between applied load and tangential velocity, and an empirical model of wear rate as a function of applied load and tangential velocity was proposed by means of central composite design. The change in the wear mechanism was associated with the subsurface plastic deformation and surface temperature, which were strongly affected by sliding speed. In addition, strain-induced martensitic transformation was observed on the sliding surface of the austenitic stainless steels.