Rolling contact fatigue assessment of railway wheel steels with wet contact

The interaction of wear and rolling contact fatigue (RCF) in railway wheel steels under wet contact was studied by means of experiments and numerical simulations. Both surface and subsurface origin fatigue was considered. The experiments were carried out by a two-disc machine with specimens of three different wheel steels, coupled with the same rail steel. Some couples were tested in fully wet contact with different sliding-rolling ratios, others in dry contact and subsequently in wet contact. In the dry-wet tests severe surface damage occurred after a few cycles during the wet phase; in fully wet tests both surface and subsurface origin RCF occurred at higher cycle number than in mixed tests. The role of wear in delaying the occurrence of surface RCF was experimentally proven. The observed phenomena were evaluated by means of a numerical code aimed at simulating different concurrent phenomena in cyclic contact.