Prediction Model of Surface Topography Evolution Due to Micropitting

Micropitting is often observed on hardened materials that are involved with rolling/sliding contact. Even though micropitting is not a catastrophic failure, it may lead to excessive wear or macroscopic pitting. Field experiences and lab testing results have demonstrated that micropitting has a strong correlation to surface topography. Surface asperity contact induces elevated stresses that in turn cause near surface material distress. In this study a micropitting prediction model, based on the contact stresses of rough surfaces, is proposed. Surface topography is modified due to micropitting. The modification of the surface topography causes a redistribution of the contact stresses. Consequently, the intervention between surface topography and the stress field may form a course of surface degradation, or the contact surface may reach steady state without generating any further micropits. The evolution of surface topography is demonstrated for different surface finishes. The comparative micropitting wear volumes and depths are summarized for these finishes.