LASER CLADDING USING THE POWDER BLOWING TECHNIQUE

A series of laser-clad samples have been produced using a 5 kW CO2 laser and a powder blowing technique. With the correct conditions, a fused bead of allay up to 5 mm wide and 1 mm thick can be formed on a surface. A wide variety of combinations of base plate and clad materials have been used, including base plates of C-Mn steel, SG cast iron and 304L stainless steel and powders made from Stellite 6, Eutrolloy 16262, Cenium Z20, tool steel, chromium white cast iron and bearing-metal alloys. With the correct process parameters the surface layer formed can be very uniform, with no porosity and little dilution by the base plate. The HAZ is small and the interface between the cladding and the substrate is very sharp, with little diffusion of the clad alloy into the base plate. This may be attributed to the very rapid heating and cooling rates produced by the laser irradiation, which also contributes to the production of a very fine as-cast microstructure.