Corrosion Behavior of Super 13Cr Stainless Steel in High CO₂/H₂S Partial Pressure Ratio Environment

The corrosion behavior of super 13Cr stainless steel in low H₂S partial pressure and high CO₂ partial pressure environment was analyzed by immersion corrosion test in high temperature and high pressure reactor. The sensitivity of the steel to stress corrosion cracking (SCC) was analyzed by uniaxial tensile test and three-point bending test. The results showed that the temperature had the most significant effect on the corrosion rate and corrosion morphology of the steel in the environment of low H₂S partial pressure and high CO₂ partial pressure. With the increase of temperature, the passivation film on the steel surface gradually changed into a corrosion product film, and the corrosion rate increased first and then decreased slowly. At high temperature, the effect of CO₂ partial pressure on the corrosion rate of the steel was obvious, showing a trend of increasing first and then decreasing. Under the condition of high CO₂/H₂S partial pressure ratio, the effect of H₂S partial pressure on the corrosion rate of the steel was not significant. The steel had high SSCC sensitivity at 24 ℃ and low SCC sensitivity at 60 ℃ and 220 ℃.