Effects of directionality of initial roughness on running-in behavior of sliding surface

Abstract

Running-in processing is an effective method to improve the tribological characteristics of the sliding surface. For example, it is possible to suppress surface damage even under more severe conditions (even if the film thickness of lubricating oil is very thin) by smoothing the surface roughness by running-in. Besides, it is known that macroscopic conformability improves the fluid loading ability on sliding guide surfaces and the like. In this research, we focus on the directionality of the initial roughness aiming at the further optimization of this running-in process. Specifically, using a four-cylinder rolling-slip tester, rollers with different directions of initial roughness with respect to the rolling direction were made to slide, and the surface changes that occurred during the running-in process were investigated, and the mechanism was examined. As a result, damage occurred before and after the valley of the roughness protrusion in the fitting process only when the initial roughness was orthogonal to the rolling direction.