EFFECT OF AC CURRENT ON CORROSION POTENTIAL OF Q235 STEEL

With the rapid development of electricity, petroleum and transport industry, more and more pipelines are buried in parallel with high-voltage transmission lines or electrified railways, and the resulting AC corrosion phenomenon has attracted more attentions. In this work, the effects of AC current density, electrolyte composition and AC current frequency on corrosion potential of Q235 steel were studied through simulation experiments, and the results are as follows: AC current makes corrosion potential of Q235 steel deviate positively or negatively depending on polarization rate of anode/cathode within different electrolytes, and the offset of corrosion potential becomes more significant as the AC current density increases or the AC current frequency decreases. Besides, the inherent mechanism of such offset induced by AC current was also studied through double layer model of interface and corrosion products analyses.