Hydrogen Entry Behavior into Steel in Immersion Environments

hydrogen overpotential were investigated in wet sour environments and ammonium thiocyanate environments using hydrogen permeation method. Logarithm of hydrogen permeability for 0.04 ％ carbon low alloy steels had a linear relation to hydrogen overpotential in sour environ- ments. This relation is independent of H 2 S partial pressure. The linear relation between hydrogen permeability and hydrogen overpotential was shown by one line for the steels with different carbon concentration and different hydrogen diffusion coefficient in sour environment as well as ammonium thiocyanate environments. Therefore, the hydro- gen permeation performance in steel is largely dependent on the hydrogen overpotential and the linear relation between them supports Gonzalez ’ s equation.