Corrosion Behavior of X80 Pipeline Steel under Different High Voltage DC Interference

The corrosion test of X80 pipeline steel was carried out by simulating high voltage direct current (HVDC) interference with a self-built device. The variation trend of interference current density and corrosion rule of the steel in Sichuan soil under different HVDC interference conditions were investigated by monitoring interference parameters and observing corrosion morphology. The results show that the current density increased rapidly to the peak value at the initial stage of interference, and then decreased rapidly and tended to be stable. The stable value was about 1/10 of the peak value. The interference duration had a certain effect on the corrosion rate, and the corrosion rate decreased with the extension of the interference duration. The interval of HVDC interference also had a significant effect on the corrosion rate. The corrosion rate increased with the extension of the interference interval, and the corrosion rate increased obviously after the interference interval exceeded 3 h. Both the defect area of pipeline corrosion protection layer and soil moisture had a great influence on the corrosion rate. The corrosion rate increased by about 4 times When the defect area decreased from 6.5 cm² to 0.2 cm². When the soil moisture increases from 17% to 34.5%, the corrosion rate increased by tens of times.