An Electron Fractographic Study of Spalls Formed During Rolling Contact.

摘要

A technique is described for making fractographs of fatigue spalls formed in bearings during rolling contact. Results are given which illustrate the usefulness of the method in identifying the fracture modes encountered in spalls. All of the fractures observed were transgranular with no evidence of any intergranular fractures. Regions of fatigue striations, cleavage, dimpled rupture and quasi-cleavage were identified in each spall examined. In a spall which initiated at a surface defect (grinding furrow), the region at the initiation point failed by forming fatigue striations. Fractographic analysis showed that the final stages of fracture were by cleavage and quasi-cleavage. (Author)