Fatigue behaviour of railway wheels at different temperatures

Abstract

Abstract This paper aims at a better understanding of the fatigue behaviour of highly loaded railway wheel materials under special consideration of the microstructural gradients in the wheels/tires due to the industrial heat treatments and elevated temperatures developing in the wheel/rail contact area during service loading. The experiments with specimens machined from original components were performed with servohydraulic testing systems. In addition to mechanical hysteresis measurements, the change of the specimen temperature and the electrical potential (voltage) due to plastic deformation processes were recorded in ambient temperature tests. Besides characteristic cyclic softening and hardening processes, dynamic strain ageing effects were observed in a defined temperature range in constant amplitude tests. The microstructural characterisation of the different material conditions was done by light (LM), scanning (SEM) and transmission (TEM) electron microscopy together with digital image processing.