Effect of Stress on Hydrogen Permeation for X70 Carbon Steel in Seawater

Previous studies of hydrogen permeation suggest that deformation associated with uniaxial tensile stress affects this behavior. However, few studies have focused on hydrogen permeation behavior during a slow strain rate test (SSRT). In order to clarify elastic and plastic deformation effects on hydrogen permeation, measurements were made by a Devanathan-Stachurski double cell during SSRT. The results show that the background current density increases in the elastic deformation range during SSRT. The hydrogen permeation current increases slowly in the elastic deformation range and decreases quickly in the plastic range due to the trapping effect by dislocations formed during plastic deformation. Competing mechanisms-dislocation trapping and dislocation transport of hydrogen-affect the hydrogen permeation current.