Corrosion Law of N80 Carbon Steel in High CO₂ Containing System

The effects of CO₂ partial pressure, temperature and corrosion time on the corrosion behavior of N80 steel in high CO₂ containing corrosion environment were studied by immersion test and electrochemical test. The results showed that the corrosion rate of N80 steel decreased with the increase of corrosion time. When the temperature was 80℃, the corrosion rate of N80 steel appeared to be the maximum. Under different CO₂ partial pressure conditions, the corrosion of N80 carbon steel had a transitional stationary period. Due to the different surface states of the electrodes, the surface of N80 steel exhibited different electrochemical impedance characteristics. The corrosion product of FeCO₃ film on N80 steel was a three-layer film structure.