1993 年 11 巻 4 号 p. 531-537
A type 329Jl duplex stainless steel was welded by gas tungsten arc welding in argon-nitrogen gas mixture atmospheres. The tensile properties and microstructures of the weld metals were examined. The nitrogen content increased and the ferrite content decreased with an increase of the nitrogen partial pressure of atmosphere. The ferrite content decreased linearly with an increase of nitrogen content. The tensile strength and elongation of the weld metal made with argon atmosphere were remarkably lower than those of the base material, but they increased with the increase of nitrogen content and were close to those of the base material at about 0.4 mass% nitrogen content. The fractography indicated that only the base material and high-nitrogen weld metals showed dimple patterns clearly. The crack paths in tensile-tested base material and high-nitrogen weld metals were complicated while those in the other weld metals were relatively straight. The tensile properties of weld metal were affected by the ferrite content and chromium nitride.