Local Plastic Indentation Resistance of Retained Austenite in Bearing Steel

抄録

This paper concerns the function of retained austenite to resist local plastic indentation deformation in bearing steel. Three austenitizing temperatures were used to adjust the morphology, volume fraction and carbon content of retained austenite in samples. The volume fraction of retained austenite was measured by magnetic method. The higher austenitizing temperature result in higher fraction of retained austenite and higher carbon content in it, and changes the morphology of retained austenite from film-like to blocky. Resistance to plastic indentation of retained austenite was measured by nanoindentation on samples with different heat treatments. Strain induced martensite transformation was observed by pop-in phenomena on indentation curves. Results showed that indentation resistance depends mostly on the local stability of retained austenite rather than the fraction and morphology. Furthermore, the local stability of retained austenite under indentation deformation is mainly attributed to the carbon content.