An Attempt To Generate Mechanical White Etching Layer On Rail Surface On A New Rolling Contact Test Bench

This study presents a successful attempt to reproduce White Etching Layer (WEL) under pure mechanical conditions, with the use of a new experimental test bench with tests conditions representative of the wheel-rail contact. The effect of the presence of a run-in or corrosive fuse layer at the rail surface has a great effect on the microstructure evolution. First, a tribological analysis of the effect of the surface preparation on material flows in the contact, hardness evolution, and formation of WEL is presented. Then a multiscale characterization approach combining optical microscopy, scanning electron microscopy and near surface EBSD characterization at the sub-mu m level has been carried out to understand the formation mechanism of such mechanically formed WEL. The different scenarios of the wear behavior and microstructural transformation were drawn. The influence of the conditions of preparation of the sample surfaces, in particular of the presence of a tribological fuse layer (either a run-in layer or a corrosive layer) on the wear fatigue competition and the WEL formation, were also studied.