The Role of Near-Surface Inclusions in the Pitting of Gears

This paper presents the results of a study combining experimental and analytical techniques to characterize the role played by near-surface inclusions in the pitting of gears. Experimental test results pertaining to failures induced by inclusions are presented in photomicrographs and discussed in terms of metallurgical considerations. A model is proposed to explain the phenomena observed in roller test specimens in terms of theoretical subsurface stress distributions that include the effect of inclusions. The model is shown to be qualitatively consistent with test results concerning microstructural alterations and microcrack propagation behavior. Finally, practical considerations pertaining to material selection and further research in this area are discussed in light of the present results. Presented at the 39th Annual Meeting in Chicago, Illinois, May 7–10, 1984