Corrosion behaviors and mechanism of X60 pipe steel in saline and alkali soil

In this paper, the corrosion behavior of X60 pipe steel is studied in the soil of alluvial plain downstream of the Yellow River based on soil property test, indoor simulation experiment, actual pipeline coating insulation test, stray current test and comparison of corrosion morphology at pipe bursting location, and actual buried situation of pipeline. Results show that the soil of alluvial plain downstream of the Yellow River is strong basic, high salt content (mainly including NaCl) and highly corrosive soil. For X60 pipe steel, uniform corrosion is slight but pit corrosion is serious, the corrosion process is that X60 pipe steel undergoes iron oxidation reaction in the soil with high water content even saturated water content and high NaCl content, an FeOOH inner corrosion product film containing water will firstly form on the steel surface and have certain protective functions against base material, but local damage may occur for inner corrosion product film due to Cl^- penetration, and thus resulting in serious pit corrosion, which may develop into pipe bursting damage.