In this work, the effect of DC interference generated by HVDC ground electrode discharging on hydrogen embrittlement sensitivity of pipeline was investigated on X70 and X80 steels, which are frequently used as materials for oil and gas pipelines. The simulated negative interferences with different amplitudes and duration were applied on X70 and X80 steel in soil environment and the hydrogen embrittlement sensitivity of X70 and X80 steels was evaluated by means of slow strain rate test (SSRT). The results show that the elongation and reduction of area, decreased with the increase of interference current amplitude and duration for X70 and X80 steels. The results indicate that the hydrogen embrittlement sensitivity increased under negative interference.

HVDC, interference current, pipeline, hydrogen embrittlement