Comparison of welding behavior of SUS316L steel by gas tungsten and gas metal arc processes in high pressure nitrogen atmosphere

Austenitic stainless steels of SUS316L were welded by GTA and GMA methods in high pressure nitrogen atmosphere and have investigated the welding condition, nitrogen absorption and microstructure. Ih the case of GTA welding could not be started are over 2.1MPa of nitrogen atmosphere, because the tungsten electrode was remarkably consumed III high-pressure nitrogen. However, in case of GMA welding, welding could be performed up to 6.1MP of nitrogen atmosphere at constant welding current of 200A and the are length of 7mm. Are voltage increased with increase in pressure of nitrogen atmosphere. Nitrogen content of GMA salidified metal increased from 0.2 to 0.65 mass % with increase in pressure from 0.1 to 6.1 MPa. Bending test indicated formation of a few micro cracks in solidified metal that included more than 0.5% nitrogen content.