Microstructure, Residual Stresses and Mechanical Properties of Laser Clad Rail Components

Increasing rates of railway deterioration requires new maintenance strategies to keep critical railway networks safe and operational. Laser cladding is an additive manufacturing-based technology that can deposit a metallurgically-bonded coating to restore worn rail profiles. An in-depth investigation has been undertaken to assess the resultant microstructure, mechanical properties and residual stresses after laser cladding both train and tram rails using different cladding alloys. A post-cladding heat treatment was found to be more effective at reducing the residual stresses than surface grinding operations. A unique combination of desirable microstructure, low tensile residual stresses and mechanical properties which complement the rail substrate has been achieved on different rail grades. This will assist in the development of a versatile laser cladding-based maintenance technique to repair and maintain essential railway infrastructure.