Rolling Contact Fatigue Life and Spall Propagation Characteristics of AISI M50, M50 NiL, and AISI 52100, Part III: Metallurgical Examination

This is the third part of a three-part series that investigates the rolling contact fatigue initiation and spall propagation characteristics of three bearing materials, namely, AISI 52100, VIM-VARM50, and VIM-VAR M50 NiL steels. Though there is substantial prior work published on the rolling contact fatigue initiation of these materials, little is known about their spall propagation characteristics after spall initiation. In Part III, 208-size, 40-mm-bore bearings are examined for changes in appearance of the microstructure as well as residual stress as a function of depth in the circumferential direction. The correlations between the experimental results from Part I and computer modeling in Part II are made.