Investigation of hydrogen embrittlement behavior in X65 pipeline steel under different hydrogen charging conditions

The hydrogen effect on a X65 carbon steel was investigated by tensile tests under both ex-situ and in-situ charging conditions. fractured samples were characterized compared using combination of scanning electron microscopy, backscattering diffraction, energy-dispersive spectroscopy. work highlights that the is necessity for investigation detrimental effects studied material, where pronounced reduction in fracture elongation, evolution secondary cracks gauge surface, corresponding brittle fractography thoroughly after testing. reason resides rapid outgassing effect, which proved Fick's law-based diffusion models. Then interrupted performed to track crack initiation propagation behavior. results show majority initiated at interfaces MnS Al 2 O 3 inclusions or between matrix, attributes elevated stress concentration around inclusions. Moreover, found propagate along {110} slip planes. • Ex-situ H method steel. In-situ more suitable embrittlement. H-induced initiate non-metallic due concentration. transgranular manner