NONEQUILIBRIUM SYNTHESIS OF FE-CR-C-W ALLOY BY LASER CLADDING

Synthesis of Fe-Cr-C-W alloy using the laser cladding technique offered an opportunity to produce a novel wear-resistant material with fine and uniform microstructure. Use of preheating during laser cladding Fe-Cr-C-W provided crack-free clads. The preheating temperature was very critical to eliminate cracks in the clad. Different complex types of carbide were observed in this research. Overall laser process parameters such as power density or specific energy as well as preheating temperature affected the characteristics of the carbide precipitates in the matrix. The increase of solid solubility and high cooling rate resulted in good metallurgical characteristics. Mostly M6C or M23C6 type carbides were observed. Usually diamond-shaped M6C carbides showed good tribological characteristics. In general, increasing the power density brought an increase of average hardness, while decreasing the power density brought a decrease of wear scar width. The laser-clad Fe-Cr-C-W alloy showed better wear properties than laser-clad Fe-Cr-Mn-C and several times smaller scar width as compared to Stellite 6 hard-facing during line-contact wear testing.