Sliding Wear of Rail and Wheel Steels: Effect of Hardness Ratio, Normal Load and Lubrication

The pin-on-disc test model system was used to simulate contact wear between wheel flange and rail gauge corner. Pins were extracted from a class C cast steel wheel and discs were extracted from premium and intermediate steel grades rail, both hypereutectoid and with hardness between 321 and 392 HB. Rails are pearlitic and the bainitic wheel is in its first life. Dry and lubricated tests were performed with normal load variation (40, 80 and 120 N). Under dry condition, there was no influence of the pair hardness to mass loss of the tribosystem studied, contrary to what is stated by literature. For the lubricated tests, mass loss was significantly lower and regardless of both, hardness ratio and normal load, than in the other tests. This shows the technological importance of: (i) implementing wheel flange lubrication (locomotive embedded process); (ii) improving rail lubrication techniques (mobile or way side process) and/or friction coefficient measurement techniques and (iii) need for revision of wheel standards and/or specifications.