Hydrogen embrittlement of a HSLA-100 steel in seawater

Hydrogen embrittlement of a copper precipitation strengthened and niobium microalloyed HSLA-1C0 steel on cathodic changing in synthetic seawater has been studied using slow strain rate technique. The effects of potential applied for hydrogen changing, pre-charging with hydrogen and changes in strain rate have been studied. A loss in ductility in terms of drop in percent elongation and percent reduction in area has been observed, the effect being prominent at potentials beyond -900 mV (SCE). SEM fractography shows an increase in brittle quasi-cleavage features with decreasing potential. A hardening effect on hydrogen charging up to -700mV (SCE), followed by a softening effect, has been observed. Precharging has led to a similar behaviour, but an overall increase in the strength values compared to material without precharging.