2017 Volume 2 Pages 82-86
Rolling contact machine elements like bearing, gear wheel and railway rail have a problem of delamination failure such as flaking, pitting and shelling. It is known that this failure is closely related to shear-mode (mode II and mode III) as well as opening-mode (mode I) fatigue crack growth. In general, the shear-mode fatigue crack growth and its threshold behavior can be significantly influenced by the interaction of opposing crack faces. Therefore, understanding of the mechanism of friction and surface damage of crack faces is essential and a novel testing method that can estimate appropriately these properties is required. In this study, the influences of the cyclic reciprocating sliding contact with microscale relative motion on the frictional behavior and the surface damage of a bearing steel were studied under dry condition. The material investigated was a heat-treated high carbon-chromium bearing steel (JIS SUJ2). As a new friction and wear testing method, a cyclic ring-on-ring test was performed by making use of a hydraulic-controlled combined axial and torsional fatigue testing machine. The coefficient of kinetic friction was ranged from 0.4 to 1.0 and its average value was about 0.75.
