Possibility of Hydrogen Embrittlement Occurrence After Cadmium Plating According to Industry-Specific Standards

Hydrogen embrittlement is a complex phenomenon that remains difficult to systematize. Despite years of research, the impact of hydrogen on metallic materials is still not fully characterized. Highstrength steels are particularly vulnerable, which has serious implications for the aerospace, automotive, shipbuilding, and energy industries. With increasing global focus on climate neutrality, hydrogenbased technologies are gaining attention, further highlighting the need for materials that combine mechanical strength with resistance to hydrogen-induced degradation. Hydrogen ingress can occur at nearly every stage of manufacturing, making planned and systematic research into hydrogen embrittlement essential for quality control. This study examines the susceptibility of AISI 4340 high-strength steel to hydrogen embrittlement after cadmium electroplating at three cathodic current densities: 0.7 A/dm², 2.25 A/dm², and 7.5 A/dm². Twelve notched specimens underwent sustained load tensile (SLT) testing over 200 hours. Surface morphology was characterized using scanning electron microscopy (SEM), and fracture surfaces were analyzed for embrittlement features. Results showed significant morphological differences in the cadmium coatings and confirmed brittle fracture zones across all conditions. The study highlights the role of current density in influencing coating integrity and susceptibility to embrittlement. The combination of mechanical and fractographic analysis provides valuable insight into how embrittlement initiates and progresses. Findings confirm that cadmium plating, regardless of current density, promotes hydrogen embrittlement in AISI 4340 steel. Thus, precise control of electroplating parameters is critical to minimize risk in industrial applications.