Cladding of Stellite-6 and vanadium carbide on carbon steel using a yttrium–aluminum–garnet laser robot system

In the present work, a laser robot system was setup for cladding and repairing machinery parts using pulsed 300 W Nd:yttrium–aluminum–garnet laser facility, six-axis robot, optical fiber, powder feeding system with a special nozzle for powder supply. A mild steel plate was deposited with powder mixtures of Stellite-6 alloy and vanadium carbide (VC). The shape of clad layer, microstructure, and its wear performance were investigated by changing the weight fraction of VC in the range of 0%–100%. The microstructure observation showed that as the weight fraction of VC in the powder mixture increases, the amount of primary solidified VC phase, penetration depth, and crack susceptibility increased. This also increased the hardness and wear resistance of the clad layer. Depending on the weight fraction of VC in the powder, the resultant microstructures can be divided into two types—hypoeutectic structure containing primary Co-rich γ phase with eutectic mixture and hypereutectic structure containing primary VC, complex carbides, and eutectic mixture.