Study on the Effect of Hydrogen in Argon-Nitrogen Shielding Gas on Pitting Corrosion for Austenitic Stainless Steel by GTA Welding Process

The addition of hydrogen in shielding gas has been found to contribute to increasing the productivity of gas tungsten arc (GTA) welding compared to the processes using argon-nitrogen shielding gas. In this report, the GTA welding joints of AISI 304 stainless steel with Ar-N 2 and Ar-N 2 -H 2 addition were fabricated. The microstructure and pitting corrosion resistance were studied in this work. The corrosion characterisation of welds metal was investigated by a potentiodynamic method in NaCl solution. It was found that H 2 addition also had effects on delta-ferrite microstructures and corrosion behaviour. Increasing hydrogen in argon-nitrogen shielding gas increased the delta-ferrite content and improved pitting corrosion resistance.