Impact of Hydrogen Charging Techniques on Hydrogen Embrittlement Behavior of S960MC AHS Steel

The study explores the influence of hydrogen embrittlement on advanced high-strength steel S960MC, focusing on the role of different hydrogen charging techniques. Hydrogen embrittlement poses a critical challenge in high-strength steels, compromising their structural integrity and limiting their applications in demanding environments. The findings indicate that S960MC steel demonstrates intrinsic resistance to hydrogen embrittlement when exposed to a hydrogen-supersaturated environment without external factors like electric current or elevated temperature. However, cathodic hydrogen charging significantly enhances hydrogen diffusion into the material, leading up to a 60% decrease in ultimate tensile strength. In contrast, immersion hydrogen charging showed a minimal effect on the mechanical properties. Fractographic analysis showed that cathodic charging led to severe embrittlement, characterized by mixed transcrystalline quasi-cleavage, intercrystalline fractures, and extensive secondary cracking. Conversely, immersion charging resulted in negligible embrittlement, with minimal changes in fracture morphology. These results highlight the critical role of hydrogen charging methods in the embrittlement behavior of S960MC steel, emphasizing the substantial impact of cathodic charging on material degradation.