Low alloyed wire electrode for GMA (MIG/MAG) welding of creep resistant boiler and pipe steels subjected to operating temperatures up to 530°C. Also suitable for joining C-Mn steels, which will be postweld heat treated. CO₂ or mixed shielding gases can be used depending on the thickness of the base metal. A thin and homogeneous copper coating increases electrical conductivity and protects the wire from rusting.