Acetic Acid Corrosion of 13Cr Steel under High Temperature and High Pressure Conditions

The corrosion behavior of 13Cr steel in solution containing acetic acid under high temperature and high pressure conditions was investigated. The corrosion rate of 13Cr increased with the increase of acetic acid concentration. When there was no acetic acid in the solution, the passive film of Cr(OH)3 formed on the surface. Pitting happened because of the existence of chloride ions. When acetic acid was added, the acidity of solution was enhanced. And the stability of the film decreased. Hydrogen ions and chloride ions could pass through the film easily. The local acidity and the concentration of chloride ions increased. Then the process of pitting was accelerated. With the increase of the concentration of acetic acid, the solution became more and more acidic. Then the pitting was promoted obviously. And the corrosion rate increased.