understand the occurrence of pitting corrosion of pipeline
Aug 01, 2014 · Pitting corrosion can be induced on pipeline steel by enhanced AC current density in both high pH and neutral pH solutions. Mechanistic models are proposed to illustrate the pitting initiation in the presence of AC based on its effect on the passive film or corrosion product layer as well as the charge distribution in double layer charge.
In fact, the pipeline steel undergoes stress corrosion cracking (SCC) , pitting , or crevice corrosion  in various soils. Red clay soil constitutes one of the major soil types in Understand the occurrence of pitting corrosion of pipeline It was found that corrosion pits could generate on the steel under CP when it encounters a polarization fluctuation. A potential field is generated locally at defects on the steel to result in an electrochemical state conversion, i.e., the cathodic polarized state changing instantly to an anodic polarization. It was proposed that, for pipelines under CP, the generation of pits is highly possible due to the frequent
Jan 15, 2012 · Pitting corrosion could occur on a cathodically polarized pipeline carbon steel when the steel experiences a potential fluctuation, and an instant, reversed potential field is generated locally at surface defects to result in the electrochemical state conversion. Consequently, anodic reaction could take place locally to initiate pitting corrosion.