Abstract: Three kinds of welding wires with different nitrogen content are used for tungsten inert gas (TIG) welding of 316L austenitic stainless steel. Microstructure, ferrite content and mechanical properties of weld metal are analyzed, and the effects of nitrogen solution and microstructure change on the strength of weld metals are investigated. Experiment results show that, with the increase of nitrogen content, the ferrite number (FN) decreases and austenite grains grow remarkably. The strength of the weld metals increases with increasing nitrogen content and it seems that the effect of nitrogen is more remarkable in the range of 0.081% to 0.10%. Both ductility and impact toughness of the weld metals decrease with increasing nitrogen content.

Key words: Mechanical properties, Microstructure, Nitrogen, Welding