PURPOSE: To decrease the dilution of base materials considerably despite welding of thin sheets and to obtain weld metal of high strength by contg. a small amt. of metallic fluoride together with metallic powder in an Ni-base composite wire.

CONSTITUTION: A titled composite wire wherein a composite wire having an Ni hoop as its sheath contains a filler consisting of 10W30% Mo, ≤15% W, 0.5W 2% metallic fluoride based on the total weight thereof, and the balance unavoidable impurities. Here, the Ni is required at about ≥50% the entire part of the wire in order to assure the toughness of the bond in the weld zone and therefore a hoop is used as the sheath. The Mo prevents the high temp. cracking during welding and increases the tensile strength of the weld zone, but if it is below the lower limit, there is no effect. In excess of upper limit, elongation decreases considerably and low temp. toughness degrades as well. The W has the effect of improving strength of the weld metal, but if it is in excess of the upper limit, low temp. toughness degrades considerably. The metallic fluoride has the effect of controlling the arc state and decreases the dilution of base materials markedly. Below the lower limit, the effect is insufficient, and in excess of the upper limit, adverse influence is given upon welding workability.