Corrosion Behavior of X80 Pipeline Steel in Simulated Manzhouli Soil Solution with Different pH

The corrosion behavior of X80 pipeline steel in simulated Manzhouli soil solution with pH of 6.2, 7.35, 8.5, 9.65, 10.8 was investigated by potentiodynamic polarization and electrochemical impedance technologies, besides, corrosion morphology of tested steel was observed. The results show that, when the solution′s pH was lower(pH was in the range from 6.2 to 9.65), the polarization curve was smooth, when the pH raised 10.8, the polarization curve appeared transient activation passive transition zone, X80 pipeline steel presented typical active dissolution characteristics in five kinds of solution with different pH; With solution′s pH rosing, the electrode polarization resistance increased, and corrosion took on a decrease trend;When the solution′s pH was 6.2, the corrosion product film was damaged, steel′s corrosion was serious; When pH was in the range from 7.35 to 9.65, pits on the steel′s surface had a similar numbers, this showed pH had little effect on corrosion; When pH was 10.8, a dense product film formed on the steel′s surface, and the corrosion of the steel was relative slight.