Laser cladding of rail steel with Co–Cr

Abstract

Degradation and subsequent failure of rail tracks are commonly caused by rolling contact fatigue among other mechanisms of wear. Rail crossings are known to exhibit more of these failures due to increased localised traffic and environmental conditions. A high proportion of the costs associated with the repair of rail tracks was due to the rolling contact fatigue phenomenon. In order to mitigate these costs, laser cladding of worn regions has been proposed for the repair of used tracks in situ to limit the need for them to be replaced and for the preservice protection of newly rolled rails and cast crossings. A Co–Cr, Stellite 6, alloy is chosen to demonstrate repair and also surface coating/protection of R260 rail steel. Results showed that cladded Stellite 6 possessed improved hardness, good tribological performance and excellent workhardening ability when compared with rail steel. These demonstrate laser cladding as a viable solution for repair worn rail track.