Effects of CO₂ Partial Pressure on CO₂ Corrosion Behavior of N80 Tubular Steel

The effects of CO2 partial pressure on CO2 corrosion behavior of N80 steel at 100 ℃ were studied by autoclave test, together with weight loss method, SEM, and XRD. The results showed that the corrosion rate of N80 steel rose with the increase of CO2 pressure corresponding to the change of corrosion product film macro-morphology. At the low partial pressure of CO2, the corrosion product film was complete, then with the further increase of CO2 partial pressure, corrosion product film turned from incomplete to complete. Accordingly, at low CO2 partial pressure, the corrosion of N80 steel was general corrosion, and then with the further increase of CO2 partial pressure, corrosion characteristics were transformed from localized corrosion to general corrosion.