Ultra-High-Speed Laser Cladding of Stellite® 6 Alloy on Mild Steel

Ultra-high-speed laser cladding, which refers to metal deposition at speeds > 20 m/min or rates of 120 cm2/min, is an emerging technique that extends the conventional laser cladding process envelope without compromising the coating quality. This research investigates the effects of the laser energy density (2.56–15.00 J/mm2) and powder stream focal position relative to the substrate (0.2–0.8 mm) on the clad layer thickness and as-deposited microstructure of Stellite® 6 coating on mild steel substrate. The laser energy density was found to be the dictating factor affecting the coating thickness, chemical composition, as-deposited microstructure, and overall coating quality. The powder stream focal position above the substrate surface determined the heated powder volume above the substrate, leading to increased coating thickness. The clad layer thickness can be controlled via changing the laser energy density and powder stream focal position.