二相ステンレス鋼溶接部における水素割れに及ぼす微視組織形態の影響に関する検討

抄録

In this study, the hydrogen cracking initiation characteristics of duplex stainless steel weld metal were investigated from microstructure level stress and hydrogen concentration. The duplex stainless steel weld metal was electrochemically charged with hydrogen and subjected to a slow strain rate tensile (SSRT) test. The cross-sectional observation was carried out after the test to investigate the relationship between the microstructure and the location of hydrogen cracking in the duplex stainless steel weld metal. A finite element model of the microstructure was generated, and elastoplastic analysis and hydrogen diffusion analysis considering the stress gradient as the driving force was conducted. The results showed that the stress concentration and hydrogen accumulation position at the microstructure level corresponded to the hydrogen crack initiation position. In addition, the characteristics of stress distribution and hydrogen concentration distribution in the case of varying ferrite/austenite fractions were investigated using a numerical analysis method.