Nitrogen absorption of Fe-Cr and Fe-Ni weld metals during gas tungsten arc welding

Fe-Cr and Fe-Ni alloy sheets were welded by gas tungsten are welding in an arc atmosphere-controlled chamber filled with argon-nitrogen gas mixtures in order to study effects of chromium and nickel on the nitrogen absorption of iron alloy weld metal. In Fe-Cr alloys, the nitrogen content of weld metal decreases with increasing welding current. In Fe-Ni alloys, the nitrogen content of weld metal hardly depends on the welding current. In each alloy, the nitrogen content of weld metal increases with the nitrogen partial pressure of the atmosphere in the low nitrogen partial pressure region, and is constant with nitrogen partial pressure more than 0.01MPa. The nitrogen content of weld metal increases with chromium content and decreases slightly with increasing nickel content. The nitrogen absorption of iron alloy weld metals is discussed thermodynamically by comparing data of arc melting and equilibrium.