Effect of phase transformation on wear of high-nitrogen austenitic 18Cr–18Mn–2Mo–0.9N steel

Dry sliding wear behavior of the high-nitrogen austenitic 18Cr–18Mn–2Mo–0.9N steel has been investigated at room temperature. Sliding wear tests of the steel were carried out using a pin-on-disk wear tester at various loads of 1–10 N under a constant sliding speed condition of 0.15 m/s against AISI 52100 bearing steel balls. The effect of heat treatments (solution treatment and isothermal aging) of the high-nitrogen steel on the wear was investigated. The wear rate of the solution-treated high-nitrogen steel remained low until 5 N, and then increased abruptly at loads above 5 N. However, the wear rate of the aged specimen increased gradually with the applied load. Worn surfaces, their cross-sections and wear debris of the steel were examined with a scanning and transmission electron microscopy together with an X-ray diffractometer. Effects of strain-induced phase transformation during the wear and nitride precipitates formed by the isothermal aging on the wear were discussed.