Laser cladding for railway repair and preventative maintenance

Rolling contact fatigue, amongst other mechanisms of wear, between railway track and train wheel ensures that periodic replacement of worn track and other key components such as switches must be undertaken. The cost associated with repairing/replacing track is significant. This places a financial burden upon the rail network provider, creates a significant carbon footprint associated with remanufacture of track, and also interruption to train services. It is proposed that laser cladding, when deployed strategically, can reduce the costs associated with replacing worn track by enhancing the longevity of new rail components (preservice) and also for the repair of sections of track which are prone to excessive wear (in service). This will lead to a cheaper, more reliable, and sustainable rail network. This paper details a series of investigations undertaken to laser clad with premium wear resistant alloys (nickel alloy, Stellite 6, maraging steel, and hadfield steel) to much cheaper rail material substrates. The methodology for process optimization is presented, and the specimens are characterized for suitability. Laser cladding is demonstrated to be a viable solution to repair worn track, and a deposition process for actual track sections is presented. (C) 2012 Laser Institute of America.