수소 주입 시간에 따른 SFCM 830S강의 취성파괴 거동 = Hydrogen Embrittlement Behavior of SFCM 830S Steel Depending on Hydrogen Charging Duration

다국어 초록 (Multilingual Abstract)

In this study, the effect of hydrogen charging duration on the hydrogen embrittlement behavior of SFCM 830S steel was investigated using an electrochemical charging method with the durations of 6, 18, and 24 h. Slow-strain-rate tests were performed at room temperature to evaluate mechanical properties, while fracture surfaces of each sample were analyzed using scanning electron microscopy to identify fracture mechanisms. Elongation to failure of the investigated specimens rapidly decreased with increasing hydrogen charging durations, with elongation reduction ratios of 27.2%, 37.7%, and 69.2% for 6, 18, and 24 h, respectively. Such results indicate a substantial influence of hydrogen embrittlement on the mechanical performance of SFCM 830S steel. The deterioration is attributed to the saturation of hydrogen trapping sites, which promotes the transition from trapped hydrogen to diffusible hydrogen and leads to localized hydrogen accumulation at stress concentration regions. Fracture analysis revealed a clear transition from ductile dimple fracture to quasi-cleavage and intergranular fracture with increasing charging duration, along with the formation of secondary cracks under longer charging conditions. This indicates the dominance of hydrogen-assisted fracture mechanisms. This study revealed a critical role of hydrogen charging duration in governing hydrogen trapping and diffusion behavior, thereby significantly affecting the susceptibility of SFCM 830S steel to hydrogen embrittlement and providing important insights for mitigating hydrogen-related degradation in industrial applications.