Hydrogen effects on cathodically charged twinning-induced plasticity steel

Cathodically charged twinning-induced plasticity (TWIP) steel was evaluated to determine the effects of brief hydrogen charging on the tensile properties. Ductile fracture mechanisms and bulk tensile properties were unaffected by hydrogen contents of up to 9.5 ppm. However, surface microcracks were observed to depths comparable to calculated hydrogen penetration depths, up to 6 μm for samples charged for 6 h. These results highlighted the limited applicability of using pre-charged tensile samples to assess the potential for delayed cracking of austenitic TWIP steels.