Abstract

The contact fatigue of carbon steel gear tooth surfaces under different lubrication conditions has been investigated and a model of the effect of lubrication conditions on contact fatigue has been established. Electrochemical corrosion forms nonferrous oxide on the tooth surface, and the crack corrosion between the nonferrous oxide and the Fe matrix may become the initiation point for contact fatigue. High temperature generated by frictional heat can accelerate the plastic deformation. Micro damage less than Hertzian contact is more likely to expand into macro pitting. The pressure around the micro damage increases when the micro damage partially coincides with the contact width, so the tooth surface around the pit is more likely to produce new pits, and then form the superposition and aggregation. The larger the lubricating oil supply, the larger the contact width, and the larger the width of the micro damage can be activated, the improvement of lubrication can promote the propagation of micro damage.