Effect of wear particles on the wear rate of unlubricated sliding metals

Abstract

By using the Okoshi wear machine, in which a hard peripheral surface of a rotating disc is pressed against the specimen plane with a load increasing in proportion to the square root of the sliding distance, the effect of wear particles in raising the wear rate K of unlubricated sliding metals is examined. After some preliminary experiments to ascertain the constancy of K during a wear test, velocity dependence, in the range of 005 ~ 3.6 m/sec, and loading dependence, in the range of the end load 1.1 ~ 9.9 kg, of K are determined. In the K vs. sliding speed curve there is a maximum in the low speed range, which shifts to a lower speed when the loading is raised. If the wear particles adhering to the sliding surface of a disc are continuously removed by a wiper, the rise of K in the lower speed range disappears. It is concluded that the abrasive action of wear particles gives rise to the higher K in the lower speed range, where centrifugal force is ineffective in removing the wear particles from the rotating disc periphery.