An Experimental Investigation of Micropitting Using a Roller Disk Machine

Micropitting is a microscopic form of progressive fatigue wear. It is most often associated with case hardened gears although such failures have also been reported for rolling element bearings. This paper reviews the micropitting phenomenon and reports the results of an experimental study conducted using a roller disk machine. Analysis of the micropitted test specimens confirmed that the roller disk machine experiments faithfully reproduce the failure mode as found on full size gears. The effect of various operating parameters was investigated. The results show that increasing load, decreasing specific film thickness and maintaining negative relative sliding all increased the rate of micropitting wear. The authors also found that micropitting is almost completely eliminated at a very low, but non-zero, slide-to-roll ratio.