Electrochemical Hydrogen Charging and Tensile Evaluation of C40 Steel: Experimental Study on Hydrogen Embrittlement Susceptibility

Hydrogen embrittlement (HE) is a critical issue affecting the mechanical integrity of metallic components, particularly in the energy sector. This study investigates the influence of hydrogen charging on the mechanical properties of C40 steel specimens through the fundamentals of the electrolysis method, using hydrochloric acid and saline solutions in the preliminary stage, concluding with a final electrolytical solution that included two buffers and one poisoning agent (acetic acid and sodium acetate trihydrate, and sodium sulfide nonahydrate, respectively). The specimens, with a thickness of 3 mm, length of 90 mm, and width of 22 mm (with a central notch and lateral radius R2 mm), at the preliminary stage were subjected to electrochemical hydrogen charging (EHC) at different current conditions for varying durations: 4 h, 6 h, 17 h, and 24 h, concluding with a duration of 24 hours for the final configuration with constant current density of 0.06 mA/cm². After charging, tensile tests were performed immediately to analyze the degradation in mechanical properties. Reference tests were conducted on non-charged specimens for comparison. The initial results show a clear trend where longer charging times lead to reduced elongation percentages, indicating increased embrittlement. Further analysis will focus on quantifying hydrogen absorption through the glycerin bath and furnace method. This research is relevant to renewable energy applications, as hydrogen storage and transport systems must ensure the structural reliability of metallic materials.