Effect of laser power and steel and nickel-based alloy substrates on hardness and wear resistance of laser-deposited stellite coatings

Stellite 6 powder was deposited by laser cladding on a variety of ferritic and austenitic steel substrates: medium carbon steel, nickel-based superalloy, martensitic stainless steel, austenitic stainless steel, and the chromium-bearing creep resistant alloys P22 and P91. Two laser powers were used: 1 kW and 1.8 kW. The chemical compositions and microstructures of these coatings were characterized by atomic absorption spectroscopy, optical microscopy and scanning electron microscopy. The microhardness of the coatings was measured and a pin-on-plate (reciprocating) wear testing machine was used to determine the wear rate for each coating.