PURPOSE: To obtain the flux cored wire for MIG welding which is used for welding of Nb-contg. ferritic stainless steels and hardly generates high-temp. weld crack.

CONSTITUTION: This flux cored wire for welding is formed by forming the sheath of the wire of a stainless steel contg. Nb stipulated as SUS 430LX of JIS and filling metallic powder and flux in such a manner that Cr is incorporated, by weight % of the entire part of the wire, at 16 to 25% Cr, Mo at 2.5 to 6% and ≥3×Nb%, Nb at 0.4 to 1.6% and Al at 0.2 to 0.8%. There is no possibility of cracking and the efficient welding at a large heat input is possible if such welding wire is used. The resulted weld metal has the heat resistance (oxidation resistance and thermal fatigue resistance) equiv. to or higher than the heat resistance (oxidation resistance and thermal fatigue resistance) of base metals. This welding material is particularly adequate for welding and assembling the exhaust system parts of automobiles.