Laser Surface Cladding of EN19 Steel with Stellite 6 for Improved Wear Resistance

The present study concerns the generation of a wear resistant Stellite 6 CO2 laser clad layer on the surface of an EN19 steel substrate by means of laser surface cladding. Laser surface cladding was carried out by melting the Stellite powder (particle size 10 to 40 mu m) supplied through a pneumatically driven powder delivery system (using a 4 MP powder unit) with a 9 kW continuous wave (CW) CO2 laser with the wavelength 10.6 mu m. The microstructure of the clad layer was found to consist of three zones: a clad layer comprised of dendrites of Stellite 6; an alloyed zone comprised of a cellular microstructure, which was a mixture of Fe and Co; and the heat affected zone (HAZ), which was a mixture of pearlite and martensite. Compared to the EN 19 steel substrate, the micro-hardness of the clad layer represented a significant improvement, increasing to 1200 VHN.