Ceramic rolling elements with ring crack defects—A residual stress approach

Experimental results of rolling contact fatigue on ceramic bearing elements with refrigerant lubrication are presented. Residual stress measurements located on the contact path and other locations on the surface are described. An X-ray method was employed. Residual stress measurements are helpful in predicting rolling contact fatigue life. In addition, analysing the relationship of residual stress with rolling contact fatigue is an important study, which will provide guidelines on the design, process and manufacturing of these elements. During this research, ring crack defects were induced in ceramic rolling contact bearing elements. A compressive residual stress value of −73 MPa near the ring crack and a comparatively lower value of −12 MPa on the contact indicate sub-surface crack initiation and propagation. The average fatigue spall ranges from 100 to 148 μm in depth. Within the spall area residual stress measurements suggest that compressive residual stress is relieved much faster in the region of sub-surface damage.