Unalloyed wire electrode for GMA (MIG/MAG) welding of unalloyed steels by using CO₂ or mixed gases, depending on thickness of the base metal. Characterized by a reduced slag formation and smooth welding deposit. Particularly suitable for welding of galvanized and pre-paint steels, welding unalloyed steels in pipe-lines, boilers and tank construction. Suitable also welding thin metal plates and repair welds. A thin and homogeneous copper coating increases electrical conducvitiy and protects the wire from using.