Prediction of residual stresses in low carbon bainitic-martensitic railway wheels using heat transfer coefficients derived from quenching experiments

Low carbon bainitic-martensitic (LCBM) steels have been recently developed for railway wheels and have been shown to provide superior properties compared to conventional pearlitic railway wheel steel grades. Pearlitic railway wheels are generally quenched at the tread region to promote the formation of compressive residual stresses in the rim to mitigate the initiation and propagation of cracks due to fatigue. However, this conventional quenching method has been shown to be unsuitable for LCBM railway wheels. Alternative quenching methods were evaluated using a FE model to develop a successful quenching process to produce LCBM railway wheels. Heat transfer coefficients were determined by employing a full scale experimental rig and were used in the FE model to model various coolant spray intensities and configurations. The FE model was used to determine optimal quenching conditions that impart compressive residual stresses to the rim of the LCBM railway wheel and the prediction of residual stresses were verified experimentally.