Effect of flow rate on localized corrosion of X70 steel in supercritical CO2 environments

The effect of flow rate on localized corrosion of X70 steel in supercritical CO2-saturated aqueous phase was studied. Results shown that flow rate changed the predominant type from general corrosion (static condition) to localized corrosion (dynamic condition), and the localized corrosion rate gradually increased with time under dynamic condition. The main localized corrosion type initiated at the early corrosion stage the local spalling amorphous layer transformed to FeCO3 scale, and localized corrosion could also occur due to the broken of dense FeCO3 scale. The critical diameter of the pit for FeCO3 scale growth inside it decreased exponentially with flow rate.