Study on hydrogen absorption of pipeline steel under cathodic charging

The hydrogen electrochemical oxidation method was used to determine the total amount of hydrogen absorbed by pipeline steels under cathodic charging. The oxidation currents were obtained for the hydrogen pre-charged specimen maintained at a certain positive potential in dilute NaOH electrolyte. The area under the current curve demonstrated a relationship with the hydrogen concentration. Hydrogen concentrations in pre-charged X70 and 16Mn steels were estimated using this method. It is shown clearly that hydrogen concentration in specimens increase as the applied current density increased, but the sensitivities of different materials to hydrogen are different. The effect of solution pH and pre-charging time on absorbed hydrogen is also studied.