The Influence of Wheel/Rail Contact Conditions on the Microstructure and Hardness of Railway Wheels

The susceptibility of railway wheels to wear and rolling contact fatigue damage is influenced by the properties of the wheel material (microstructure and hardness). These properties are influenced by the steel composition, wheel manufacturing process, and by the stresses experienced during operation. The in-service properties can therefore vary with depth below the surface, and with position across the wheel tread. This paper discusses the stress history at the wheel/rail contact (derived from dynamic simulations) and the variation in hardness and microstructure with depth from the wheel tread (measured on wheels removed from service). The results are linked to the observed rolling contact fatigue resistance of railway wheels.