Purpose Hydrogen embrittlement and stress corrosion cracking have been regarded as major threats to the safe operation of hydrogen transportation pipelines. This study aims to investigate their combined effects on the cracking behavior of specimens simultaneously exposed to gaseous hydrogen and simulated soil solution. Design/methodology/approach Using a hollow cylindrical specimen of 20# seamless steel, the combined effects of internal gaseous hydrogen and external corrosion on cracking behavior are investigated. Findings The findings demonstrate that they can jointly enhance cracking susceptibility, exhibiting greater effects than when considered individually. Under the combined action, the fracture surface after slow strain rate testing exhibits distinct morphologies: quasi-cleavage morphology induced by hydrogen embrittlement and stress corrosion cracking, respectively, as well as dimple morphology caused by sole mechanical fracture. However, the presence of hydrogen embrittlement results in a reduction in both the number and depth of stress corrosion cracks. Furthermore, the area and depth of cracks caused by hydrogen embrittlement are also marginally reduced because of stress corrosion cracking. Originality/value This study introduces a novel method using a hollow cylindrical specimen to investigate the combined effects of internal gaseous hydrogen and external corrosion on cracking behavior in 20# seamless steel. Additionally, this approach offers valuable insights into the interaction between gaseous hydrogen embrittlement and external corrosion.
Du et al. (Fri,) studied this question.