Effect of shaft voltage on electric damage of GCr15 bearing material

Electrical erosion pit is a fundamental manifestation of electrical bearing damage. As the shaft voltage increased, the degree of electrical damage became more severe, and the residual compressive stress and hardness of bearing surface decreased. The transition of martensite into ferrite induced by high discharge temperature was found at the edge of the erosion pit using a transmission electron microscopy. This phenomenon has not been observed below the mechanically rolled surface under the same conditions. Electrical penetration harmed the bearing through surface erosion, lubrication deterioration and martensite decomposition. The electrical pit could be observed when current density exceeded 0.95 A/mm². The results can help understand bearing failure in the fields of railways, wind turbines, and new-energy vehicles.