Dislocation Slip and Damage Evolution Behavior in the Dent-Induced Pitting Process of M50 Bearing Steel

Pitting is a typical failure behavior in rolling contact fatigue. Generally, there are two different pitting cases. One is the corrosion-induced pitting, and the other is the dent-induced pitting. This study focused on the dent-induced pitting. The surface dent is caused by the particle compression on the ring surface. During the compression process, grain distribution affects the dent geometry and the damage evolution behavior. However, researchers have almost ignored the effects of grain distribution on surface defect-induced RCF. Therefore, the authors proposed a crystal plasticity continuum damage method (CP-CDM) model by combining crystal plasticity constitutive equations with continuum damage equations to study the grain distribution effects on the damage evolution of the surface defect-induced RCF. The results show that the proposed model can simulate the crack propagation characteristics of the RCF. Grain distribution has effects on the damage propagation behavior randomly. However, the lead cracks have little difference for different grain distribution microstructures. The damage evolution behavior of pitting is affected by the interaction between stress concentration from the shoulder and the crack tip and strain localization from the grain boundaries. Moreover, the cracks in the surface pitting and the subsurface spalling evolve simultaneously.

Graphical abstract