Railway axles are one of the most critical components in rail industry since their failure can lead to the derailment of railway vehicles and loss of lives and properties. These components suffer from a wide range of damage including corrosion, electrical arcing, and fatigue and most importantly wear due to excessive loading. Every year rail operators around the world scrap thousands of railway axles due to the size of their two bearing journals being under tolerances and sizes defined for them. The current standards for manufacturing and maintenance of rail axles only allow for non-thermal processes such as brush plating to be used to repair the worn rail axles as thermal processes as they may create heat affected zones with degraded properties in these components. In this study the possibility of using laser cladding which is a thermal process as a repair technology for refurbishment of railway axles is investigated which was proposed for the first time in 2010 by Hardchrome Engineering Pty Ltd, Melbourne, Australia. The economic rationale behind this idea was that replacing each worn axle would cost 2500 Australian dollars whereas repairing them with laser cladding would cost only 1000 Australian dollars per axle, provided that the feasibility of this technology and suitability for railway axle applications is proven. Mild steel which is one of the most widely used materials in the manufacturing of rail axles was used to prepare hour glass fatigue samples to be tested under rotary bending fatigue condition using a dedicated testing machine which was designed and used at Hardchrome Engineering. These samples were tested without any laser deposition to demonstrate the fatigue data of axles which were not worn. To simulate worn railway axles, a groove was machined in each fatigue sample which was later filled by laser cladding as a simulation of a refurbished rail axle. Two different cladding materials were used to build up undersize machined samples which were 420 stainless steel and CrMoV. The laser clad samples were then heat treated at a wide range of temperatures to investigate the effect of post-clad heat treatment conditions on the fatigue properties of laser clad samples. The fatigue results of the clad samples were compared to those of the non-clad samples to investigate the effect of laser cladding on the fatigue properties of the samples
