Influence of hydrogen on the mechanical properties of some medium-strength Ni-Cr-Mo steels

Our recent work is reviewed on the influence of hydrogen on the mechanical properties of four medium-strength Ni-Cr-Mo steels, studied using the linearly increasing stress test (LIST). Cathodic hydrogen charging at different negative potentials was used to produce the different hydrogen conditions. All four steels have good resistance to hydrogen up to the yield stress, especially NiCrMo1. Somewhat lower ductility occurred due to the presence of alumina oxides inclusions. Their performance in a hydrogen environment may be improved by reducing the density or the size of inclusions.