The laser cladding of Hastalloy to critical surfaces of Stainless Steel components

Laser cladding of the nickel alloy Hastalloy, C276 (Ni59-Mo16-Cr15.5-Fe-5-W 3.7) on a stainless steel 316L substrate was investigated. The objective was to establish the feasibility of the deposition of the highly corrosion resistant C-276 alloy on the stainless steel substrate as a means of removing the need for machining parts from solid C-276 alloy in chemical storage and reaction vessel applications. Cladding was carried out with a 2kW carbon dioxide laser using the blown powder method. The process was found to be effective with a high quality clad being deposited on the stainless steel substrate. Microstructural studies indicated that the clad was devoid of cracking, has a low level of porosity and has a microstructure favourable for good corrosion resistance. The quality and nature of the metallurgical bond between the clad layer and the substrate and the degree of dilution were investigated in terms of the laser cladding parameters (powder flow rate, laser power, substrate traverse rate, degree of track overlap). Characterisation was carried out by optical microscopy and SEM.