The metallography of worn surfaces and some theories of wear

Abstract

The experimental difficulties and polishing artefacts associated with near-surface metallography are discussed. Micrographs are presented of sections taken through a hard steel surface lightly rubbed by a grinding wheel to illustrate these difficulties and to show how they may be overcome. The implications for the delamination theory of the subsurface alterations observed here and those reported in the literature are then discussed, and a new classification of wear processes is proposed on the basis of contact stress. Finally, it is suggested that many of the aspects of wear explained by the delamination theory may also be explained in other ways, and that more careful metallography is needed to define how far each theory applies.