Hydrogen Permeation Susceptibility and Behavior Related to Applying Pre-Strain on Ultra-High Strength Steels

The Devanathan-Stchurski cell has been successfully used to determine and describe hydrogen permeation behaviour in ultra-high strength steels for automotive car-body. As the tensile strength and ratio of martensitic microstructure increases, diffusivity and permeability of hydrogen in bulk metal is proportionally increased. And the electrochemical permeation tests were performed on tensile straining of several kinds of the low carbon steels for investigating the influence of dislocations generated by plastic deformation on the stationary hydrogen flux. The main parameters were the strain and the hydrogen activity. The behavior about the plastic strain was observed as the decrease of the steady state flux depending on the electrochemical charging conditions. The decrease of the hydrogen flux can be attributed to dynamic trapping to strain-induced dislocations.