A method for predicting ratcheting and wear in rolling contact fatigue, taking technological residual stresses into consideration

Abstract

The main aim of our study is to show the influence of residual stresses on wear and surface ratcheting in the case of line rolling contact. Experiments were carried out on the innovated TUORS (Technical University of Ostrava Rolling Sliding testing machine) testing rig under free rolling and also under a slip ratio of 0,75 %. All specimens used for the experiments were made from R7T steel. A hole-drilling method and an X-ray diffraction method were applied to determine the residual stresses induced by repeated contact loading and technological residual stresses. Mazzu's semi-analytical approach, which makes use of full integration of the Armstrong-Frederick model, was used to simulate ratcheting and wear. The proposed model calibration methodology, based on an inverse approach, allows the model parameters to be determined directly from the measured wear. The results of this study confirm that the observed technological compressive residual stresses lead to lower ratcheting and subsequently also to lower wear rates.