Effect of Temperature on Hardening and Residual Stress Development During Wheel/Rail Rolling Contact

Brake heating of Railroad Wheels has been known to accelerate shelling, soften the wheel tread and contribute to stress reversal which is a requisite for generating thermal cracks. The effect brake heating has on shakedown has been investigated to a lesser extent, yet even here brake heating can be very important. This research combines field investigations and laboratory work in an attempt to quantify the thermal effects on wheel performance, especially as it relates to sub-surface shelling, microstructural changes and hardening mechanisms. Cyclic tensile tests were conducted at three temperatures to show the relationship between deformation at elevated temperatures and hardening response. Ductility measurements from both monotonic and cyclic tests were used to estimate residual stresses.