Effect of alternating current density on corrosion behaviour of X65 steel in weakly alkaline soil environment without cathodic protection

The corrosion behaviour of X65 steel in Shijiazhuang soil-simulated solution was investigated under different alternating current (AC) interference. Results show X65 pipeline steel presented weak passivation characteristics in this weakly alkaline solution, in which case AC interference could activate the anodic dissolution reaction and greatly accelerate uniform corrosion and pitting corrosion. AC interference could easily induce corrosion pits initiation and propagation in this weakly alkaline solution because of unstable passive film on steel surface and low pitting potential. Both the average corrosion rate and corrosion pits depth presented a power function with the increase of AC density.