Small amounts of nitrogen have been added to Ar-1% 02 to achieve a completely austenitic microstructure in welds made with type 347 stainless steel filler metal. Nitrogen concentrations in the range of 1.5 to 3% have been used. Quantities above 10% produced considerable fuming but welds are sound. Additions greater than 2% N2 produced porosity in single pass GMAW welds made in mild steel; additions less than 1/2% caused porosity in multi-pass GMAW welds in carbon steel. A few attempts have been made to utilize N2 rich argon mixtures for GMAW welding of copper and its alloys, but spatter percentage is high.