Abstract: Stellite6+WC composite coating was deposited on the surface of 17-4PH stainless steel by using laser cladding method. The optimal cladding parameters suitable for Stellite6 alloy were obtained through orthogonal experiments, and then different contents of WC powder were added to the coating under these cladding parameters. By using optical microscope, microhardness tester and salt spray corrosion test chamber, the effects of WC addition and laser quenching technology on the microstructure, Vickers hardness, and salt spray corrosion resistance of the clad coating were compared and studied. The results indicate that the optimal cladding parameters are laser power of 1500 W, laser scanning speed of 18 mm/s, and focal distance of 13 mm. When the mass fraction of WC is within 30%, the microhardness and salt spray corrosion resistance of the Stellite6+WC clad coating gradually increase with the increase of WC content. However, when the mass fraction of WC is higher than 30%, the microhardness and salt spray corrosion resistance of the clad coating are not significantly improved compared to that of the cladding with 30%WC. Although the laser quenching process improves the microhardness and salt spray corrosion resistance of the cladding to some extent, the salt spray corrosion resistance of the coating after laser quenching at 3000 W is not further improved compared to that after laser quenching at 1000 W.

Key words: laser cladding, laser quenching, microstructure, microhardness, salt spray corrosion resistance