Mechanical and thermomechanical loadings on train wheels occur during use. Improvements in the thermomechanical properties of wheel materials can help to reduce the incidence of fatigue damage, and thereby reduce the risk of catastrophic failure and derailment.

The project successfully characterized the fatigue behavior of high-load UIC wheel steels at elevated and service relevant temperatures under brakeage and slippage. Besides constant amplitude isothermal fatigue tests, we conducted tests at elevated and time variable temperatures to examine the impact of thermomechanical loadings on fatigue behavior. We sampled actual railway wheels in defined cross-sections in order to assure the best possible mapping of the microstructure-gradients. We examined fatigue behavior and characterized it by mechanical stress-strain hysteresis and electrical measurements.

Using several microscopy techniques, we could identify the correlation between microstructure and physical measurements for characteristic fatigue stages.