Laser cladding of WC-dispersed stellite on carbon steel

Abstract

CO2 laser cladding of Stellite, in which tungsten carbide WC is dispersed, is done on carbon steel. Microhardness HV of the Stellite clad layer is 600-700, which is obtained under the conditions of the laser power of 2.3 to 2.9 kW, cladding repetition number of 1 or 2 (layer thickness of 0.8 or 1.6 mm), cladding speed of 400 mm/min, defocusing distance of 30 mm, oscillation width of 7 mm of laser beam and shielding argon gas. The layer is formed by the fine dendrite structure (secondary dendrite arm spacing of 3 μm) and eutectic structure due to the rapid solidification; tungsten carbide particles are uniformly dispersed in the layer matrix. A heat affected zone is also produced on the surface layer of the base metal with the martensitic structure. For removing the residual stress in the base metal, the sample is annealed by lower power beams; the martensite of the heat affected zone is transformed into troostite. The hardness of the clad layer is not changed. EΡMΑ analysis indicates that an alloyed layer of the thickness of 30 μm is produced between the clad layer and base metal.CO2 laser cladding of Stellite, in which tungsten carbide WC is dispersed, is done on carbon steel. Microhardness HV of the Stellite clad layer is 600-700, which is obtained under the conditions of the laser power of 2.3 to 2.9 kW, cladding repetition number of 1 or 2 (layer thickness of 0.8 or 1.6 mm), cladding speed of 400 mm/min, defocusing distance of 30 mm, oscillation width of 7 mm of laser beam and shielding argon gas. The layer is formed by the fine dendrite structure (secondary dendrite arm spacing of 3 μm) and eutectic structure due to the rapid solidification; tungsten carbide particles are uniformly dispersed in the layer matrix. A heat affected zone is also produced on the surface layer of the base metal with the martensitic structure. For removing the residual stress in the base metal, the sample is annealed by lower power beams; the martensite of the heat affected zone is transformed into troostite. The hardness of the clad layer is not changed. EΡMΑ analysis indicates that an alloyed layer...