Observations of the Peeling Mode of Failure and Surface-Originated Flaking from a Ring-to-Ring Rolling Contact Fatigue Test Rig

The ring-to-ring rolling contact fatigue rig is a standard test rig for producing rolling contact fatigue. It is suitable for basic research on rolling contact phenomena. Observations of two types of surface cracks, peeling microcracks under moderate contact stress and surface cracks due to excessively high contact stress, are described in this paper. The peeling grade is related to the metallic contact ratio. The running-in property observed in metallic contact monitoring is an important factor in determining the relationship between the lubricant's characteristics and peeling failure. Rolling contact under high contact stress produces surface-originated flaking by a crack initiation mechanism, that is, crack initiation resulting from fatigue by repeated cycles of small tension and large compression.