Laser cladding of nickel-based hardfacing alloys

The effects of powder feed rate (PFR) and translation speed (TS) of a laser beam were investigated on laser cladding with three nickel-based hardfacing alloys: Colmonoy 6, Colmonoy 88 and AI-1236. The width-to-height ratio of single clad passes and the extent of dilution were found to decrease with increasing PFR and decreasing TS. Microstructurally, Colmonoy 6 clad layers consisted of a nickel-based structure of primary gamma-nickel dendrites and interdendritic eutectics of y-nickel, nickel borides and nickel silicides, Colmonoy 88 of mixed carbides and AI-1236 of partially melted WC particles and mixed carbides embedded in similar nickel-based microstructures. Block-on-ring wear tests showed that the wear mechanism is largely abrasive in nature for all three alloys studied. The wear resistance was found to correlate better with the type and amount of the main hard phase present in the clad layer: AI-1236 clad layers were much superior to those of Colmonoy 6 and Colmonoy 88 clad layers owing to WC particles in the alloy. (C) 1998 Published by Elsevier Science S.A.