Abstract: A welding wire for automatic arc welding, which is particularly suitable for use in build-up welding operation for the purpose of providing hard surface to a metal die. The welding wire consists of a continuous tubular metal casing and a core composition charged in the interior of the casing and comprises such amounts of Ni, Si, B, Nb and C as essential alloying elements that the deposited metal contains at least 40% of Ni, 3-8% of Si, 0.1-0.4% of B, 0.3-1.8% of Nb and 0.2-1.5% of C, all by weight. Preferably, either a practically pure Ni strip or an Fe-Ni alloy strip is used as the material of the casing, and the core composition in the form of a powder mixture contains necessary amounts of Ni, Si, B, Nb and C, optionally with the addition of a small amount of Zr. The deposited metal given by this welding wire has high wear resistance and good antifrictional property and seldom suffers from weld cracks.

Abstract: A covered electrode for shielded metal arc welding, which is particularly suitable for use in build-up welding operation for the purpose of providing hard surface to a metal die. The covered electrode comprises such amounts of Ni, Si, B, Nb, C and Zr as essential alloying elements that the deposited metal contains at least 40% of Ni, 3-8% of Si, 0.1-0.5% of B, 0.3-2.0% of Nb, 0.2-1.5% of C and 0.01-0.20% of Zr, all by weight. In a preferred form, either Ni wire or Fe--Ni wire is used as the core wire, and the covering contains necessary amounts of all the essential alloying elements except Ni. The deposited metal has high wear resistance and good antifrictional property, and the presence of Zr is highly effective for preventing the occurrence of weld cracks.