Hardness Effect on Three-Body Abrasive Wear Under Fluid Film Lubrication

Abstract

Under fluid film lubrication, the particulate contaminants in the fluid cause three-body abrasive wear on critical surfaces. The wear not only depends on the hardness of the wearing surface (Hj ), but also on the hardnesses of its opposing surface (Hb ) and the involved abrasives (Ha ). In this paper, the hardness effect, particularly the relationships among these three hardnesses, is studied, by exploring the interdependence between two hardness ratios: the ratio between two rubbing surfaces (Hb /Hj ) and the ratio between the surface to be protected (usually the harder surface) and the abrasives (Hj /Ha ). Three types of journal-bearing pairs (Hb /Hj = 0.75, 0.6, and 0.3) were tested, subjected to four abrasive particles (Hj /Ha ranges from 0.14 to 2.75). The wear linearly varies with the Hj /Ha value at each metal hardness ratio on log-log diagram. The empirical constants in the wear function are obtained. The critical hardness ratio and the wear coefficient are also analyzed.