Sliding wear characteristics of low temperature plasma nitrided 316 austenitic stainless steel

The sliding wear behaviour of plasma nitrided layers produced in AISI 316 type austenitic stainless steel at temperatures between 450 degrees C and 550 degrees C has been investigated in the present work. Both dry sliding test with bearing steel and alumina as the counterface and sliding test in a corrosive solution have been conducted. The results show that the sliding wear behaviour of plasma nitrided 316 steel depends on the nitriding temperature, counterface material and testing conditions. Under dry sliding conditions, plasma nitriding at various temperatures increases the wear resistance of 316 steel by more than two orders of magnitude when sliding against bearing steel. When sliding against alumina under dry conditions, the low temperature (450 degrees C) nitrided layer, which comprises predominantly a single 'S' phase, is more effective in improving the wear resistance of 316 steel. When sliding in a corrosive solution, no improvement in corrosion wear resistance has been observed for the high temperature nitrided layers, whilst the low temperature nitrided layer, as compared with untreated 316 steel, exhibits not only improved corrosion resistance but also much increased corrosion wear resistance under the present testing conditions. Accordingly, combined corrosion and wear resistance of 316 steel can be achieved by plasma nitriding at low temperatures to produce a thin and precipitation-free layer with high hardness and good corrosion resistance. (C) 1998 Elsevier Science S.A. All rights reserved.