摘要：High nitrogen stainless steel with nitrogen content of 0.75% was welded by gas metal arc welding with Ar–N 2 -O 2 ternary shielding gas. The effect of the ternary shielding gas on the retention and improvement of nitrogen content in the weld was identified. Surfacing test was conducted first to compare the ability of O 2 and CO 2 in prompting nitrogen dissolution. The nitrogen content of the surfacing metal with O 2 is slightly higher than CO 2 . And then Ar–N 2 -O 2 shielding gas was applied to weld high nitrogen stainless steel. After using N 2 -containing shielding gas, the nitrogen content of the weld was improved by 0.1 wt%. As N 2 continued to increase, the increment of nitrogen content was not obvious, but the ferrite decreased from the top to the bottom. When the proportion of N 2 reached 20%, a full austenitic weld was obtained and the tensile strength was improved by 8.7%. Combined with the results of surfacing test and welding test, it is concluded that the main effect of N 2 is to inhibit the escape of nitrogen and suppress the nitrogen diffusion from bottom to the top in the molten pool.
