Study of AC Corrosion on Coated Pipeline Steel in Simulated Soil Solution

Buried pipelines paralleling or corrosing the high voltage powerlines systems are often subjected to induced AC interference, which may cause seriously corrosion risk. There has so far many conclusions including size of coating defects, AC current density, etc. to estimate corrosion condition, but no perfect evaluation criterion was conducted. In this paper, the AC induced corrosion of coated pipeline was studied with coated specimens in simulated soil solution under various experimental conditions to determine the AC corrosion risk considering the cathodic protection, coating defectes, AC current density, soil acidity/alkalinity, the soil resistivity, etc. integrally.

It has been known that failuer accident in oil and gas transmitting pipeline always performs destructive pitting which was cased by AC interference. Pitting corrosion was also studied in this paper by electrochemical measurements, and AC corrosion mechanism was further analyzed. Specific morphology characteristics of AC corrosion were observed by SEM technical.