Evaluation of the Contact Durability of 65G Steel by the Criterion of Exfoliation

Abstract

We proposed numerical algorithms and use these algorithms to determine the stress intensity factors for the subsurface cracks in a half plane. We also constructed the paths of their propagation under the action of moving model (elliptic) contact loads. The fatigue-fracture diagrams were experimentally established for the model 65G wheel steel under the mode II and mode I conditions. The residual contact durability was estimated according to the formation of exfoliations in the near-surface zone of railroad wheels made of 65G-type steel. We also studied the dependence of residual service life on the operating and geometric parameters, such as friction/lubrication in the zone of contact between the wheel and the rail, friction between the crack faces, the depth of location of initially rectilinear cracks, and the intensity of loading of the rolling couple. The shapes and dimensions of exfoliations are also predicted.