Hydrogen Embrittlement in a Plasma Tungsten Inert Gas-Welded Austenitic CrMnNi Stainless Steel

The study evaluates the effect of electrochemical hydrogen charging on the tensile properties and fracture behavior of the plasma tungsten inert gas weld of the high-alloy austenitic steel X3CrMnNiMoN17-8-4 in comparison to the pure base metal (BM). The weld metal exhibits a higher susceptibility to hydrogen embrittlement than the BM, which is mainly expressed by a loss in ductility. Based on the performed electron backscatter diffraction and X-ray diffraction examinations, this is attributed to the higher amount of delta-ferrite and the higher dislocation density in the weld zone. Furthermore, fractographic analyses reveal a change in the manner of fracture mode from ductile to brittle fracture starting from the edge in the hydrogen charged samples. The wider area of brittle fracture in the weld seam in relation to the BM indicates that hydrogen penetrates deeper into the material. Consequently, the diffusivity of hydrogen in the weld seam is determined to be significantly higher than in the BM.