Factors Affecting the Hydrogen Embrittlement Resistance of Ni-Cr-Mn-Nb Welds

摘要

Nickel based alloys are often welded with argon/hydrogen shielding gas mixtures to minimize oxidation and improve weld quality. However, shielding gas mixtures with (ge) 1% hydrogen additions can result in hydrogen concentrations greater than 5 wt. ppm in the weld metal and reduce ductility via hydrogen embrittlement. For the conditions investigated, the degree of hydrogen embrittlement is highly variable between 5 and 14 wt. ppm. investigation of hydrogen embrittlement of EN82H GTAW welds via tensile testing, light microscopy, transmission electron microscopy, orientation imaging microscopy, and thermal desorption spectroscopy shows that this variability is due to the inhomogeneous microstructure of the welds, the presence of recrystallized grains, and complex residual plastic strains.