Comparing and analysing the characterisation of laser cladding of CrNiW and CrNiFeAlZr powders on H13 tool steel

Cladding-based repair has been found to be superior than welding or flame spraying repair approaches in terms of extending die life. In this work, two different alloy powders, that is, CrNiW and CrNiFeAlZr were coated on H13 steel using laser cladding. The laser power, powder feed rate and scanning speed were varied and the clad dimensions, aspect ratio and dilution percentage were measured. The microhardness found in the CrNiW clad is 834 +/- 20 HV0.5, which is higher than that of the CrNiFeAlZr clad (780 +/- 20 HV0.5) as well as the substrate clad (548 +/- 20 HV0.5). CrNiW clad has a higher microhardness than CrNiFeAlZr clad and substrate, indicating that CrNiW laser cladding has a significant impact on microhardness. The interface region for CrNiFeAlZr has 8.33% of C, which is less than the interface region for CrNiW (10.65% of C) so that the microhardness at the interface in CrNiW clad is high. The XRD patterns identified the common phase creation of Ni3C and Fe3C for CrNiFeAlZr and CrNiW coatings, while the oxide formation was only seen in CrNiFeAlZr coatings and the addition of carbon content in the CrNiW clad layer forms WC, Cr23C6, Ni3C and Fe3C. A response surface methodology with a Box-Behnken design is used in the optimisation process.