Friction induced martensite transformation and wear resistance of 18Cr2Ni4WA steel under boundary lubrication

Different retained austenite contents were obtained in the 18Cr2NiWA steel carburized and quenched by subzero treating at different temperatures. The specimens were tested under boundary lubricated sliding wear against T10 steel plat by the pin on disk method. The results show that friction induced martensite do exist in the course of wear, and the retained austenite with lower carbon content is easier to transform to martensite than that with higher carbon. Friction induced martensite is always benefit to improving the wear resistance, but there exists a threshold stress value σ_c for retained austenite affecting the wear resistance. When the stress is greater than σ_c, the retained austenite is benefit to improving the wear resistance, otherwise it will impair the wear resistance. The wear resistance will reach a maximum when the retained austenite content fits with the external stress.