Experimental Study on the Corrosion of Buried Pipeline in Coastal Area Under the Interference of Stray Current

To explore the effect of stray current and the concentration of Cl- on corrosion of buried pipeline in coastal area, in this paper, indoor electrochemical experiments were used to change the voltage of AC interference. The electrochemical parameters such as zero current potential error, Tafel constant and corrosion current density error of the polarization curves obtained in three different concentrations of Cl- solutions without alternating current interference and with different intensities of alternating current interference were compared and measured. The results showed that the corrosion potential of the sample was shifted negatively. When the interference ratio of the fixed voltage was not disturbed, the corrosion current increased, and the corrosion process changed from cathode reaction control to hybrid control. AC stray current could aggravate the corrosion process of Q235 steel. In the presence of AC stray current, with the increase of applied AC voltage, the corrosion potential of Q235 steel moved negatively, the corrosion current density increased and the corrosion rate accelerated. The concentration of Cl- had a great influence on the reaction rate, and the higher the voltage, the more obvious the effect. This is of great significance for effectively predicting the life of buried pipelines, improving the reliability of buried pipelines during service and protecting the safety of existing pipeline facilities.