Noboru Yahata1 and Fusao Hayama2
1Department of Mechanical Engineering, Faculty of Technology, Tokyo University of Agriculture and Technology, Koganei
The nature and mechanism of the formation of the hard patch formed on the rubbed surface of carbon steels under a moderate sliding condition in air have been studied.
The results obtained are as follows:
(1) The hardness of the hard patch increased with carbon content, and this change with tempering temperature decreased more slowly than the conventional martensite.
(2) In general the hard patch contained fine oxide fragments. The hard patch was not observed in pure iron and austenitic stainless steel unhardened by the normal heat treatment.
(3) The hard patch formed a sharp boundary with the substrate, but electron microscopy revealed that the transition was continuous.
(4) It was suggested that the hard patch might bring about a reduction in the wear rate of the steels.
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