Prediction of the Initial Residual Stresses in Railway Wheels Induced by Manufacturing

Abstract

This article presents a prediction of the residual stresses that are introduced by the heat treatment in the manufacture of railway wheels. It is well known that this treatment induces the formation of a layer of residual circumferential (hoop) compressive stresses on the tread surface. This stress field may be reversed during service loading, especially tread braking. Tensile stresses at the wheel tread that arise from repeated braking may lead to the initiation of surface cracks. The work presented here defines a methodology for determining the as-manufactured residual stress field prior to service loading. A thermal and mechanical finite element model was used to study the residual stress evolution during the heat treatment. The heat transfer coefficient during quenching was determined by means of a dedicated experimental setup. The results show that the numerically computed residual stresses correlate strongly with the experimental residual stresses determined by ultrasound when the model material includes time-dependent effects such as creep or viscoplasticity.