1992 Volume 78 Issue 10 Pages 1585-1592
Formation of hardfacing clad layers by laser cladding with blown powder and their wear properties have been investigated. Co base hardfacing alloys, and niobium carbides or chromium carbides mixed Co base alloys were deposited on to mild steel substrates with varying laser power and traverse speed under constant amount of powder feeding per unit bead length.
Dilution and area of melted substrate linearly increased with heat input per unit bead length. Melting efficiency for substrate melt in the laser clad was approximately one-sixth of that in laser surface melting, since the substrate was melted indirectly by heat from melting clad layer. This is the reason why low dilution can be obtained easily in the wide range process variables. Dilution in the carbide mixed clads was lower than that in Co base alloy clad, since melting of the former may require higher heat input than that of the latter.
In Co base alloy clads, wear resistance enhanced with increasing hardness of clad layers. In the carbide mixed clads, significantly higher wear resistance was obtained than that estimated from their matrix hardness because of high hardness of carbide particles.
