Influence of the Microstructure on the Subsurface and Surface Damage during Lubricated Rolling–Sliding Wear of Sintered and Sinterhardened 1.5%Mo–2%Cu–0.6%C Steel: Theoretical Analysis and Experimental Investigation

The influence of the microstructure on density on the resistance to subsurface and surface damage, during lubricated rolling–sliding wear of a 1.5%Mo–2%Cu–0.65%C sintered and sinterhardened steel, was investigated. The nucleation of subsurface contact fatigue cracks and the occurrence of surface plastic deformation due to surface stresses were studied through a theoretical analysis and confirmed through wear tests. The expected positive effect of density and sinterhardening was confirmed. Moreover, the resistance of the steel to the two damage mechanisms investigated depends on the microstructural heterogeneity. The theoretical model for subsurface and for surface damage may be used to predict the resistance of the material but, depending on the distribution of the microstructural constituents, either a local or a mean approach in defining the properties of the metallic matrix has to be used.