Dry sliding wear of nanostructured carbide-free bainitic steels – Effect of oxidation-dominated wear

Abstract The microstructure has a profound impact on sliding wear behaviour. This paper aims to understand the effect of carbide-free bainitic microstructure on oxidation-dominated wear in a self-mated dry sliding contact and compare the results with quenched and tempered martensitic microstructure. The results show improved wear resistance of the carbide-free bainitic steel austempered at low temperature. Hence, the retained austenite content of the carbide free bainitic microstructure is not the only indicator of excellent wear resistance. Compared to tempered martensitic microstructure, the carbide-free bainite offers a higher resistance against the formation of brittle white etching layer during the sliding wear. In summary, the formation of a thin and mechanically stable compositional mixed layer on top of the surface together with a hard underlying substrate are the main reasons behind the improved wear performance of carbide-free bainitic steel austempered at low temperature.