The evolution process of fluting damage on bearing outer races during rolling with a shaft current

This study focuses on the evolution of fluting damage in bearing outer races. Fluting damage first occurred at the loading position and then extended along outer races. This non-uniform distribution of fluting damage is related to the non-uniform load inside bearing. It is speculated that the alteration of bright and dark areas in fluting is related to the periodic destruction and reconstruction of lubricating film. The phase transition from α′-Fe to α-Fe is observed beneath erosion surface. At microscale, non-uniform damage of the fluting appears as the dark area exhibiting more severe erosion, lower oxidation, greater roughness, deeper depth, and lower hardness. The results can provide deeper understanding of the failure process and damage mechanism of bearings in electric fields.