Corrosion Resistance of N80 and P110 Steels in High Pressure and High Temperature Steam

The steam environment in thermal recovery was simulated using high temperature and high pressure autoclave, corrosion experiments of N80 steel and P110 steel which were taken from oil field were conducted. Then, the morphology and chemical composition of corrosion product film were studied by scanning electron microscopy (SEM) and X-Ray diffraction (XRD), and the corrosion mechanism in mixture high temperature and high pressure steam was studied. The results showed that the corrosion of mixture steam was serious, both O2 and CO2 were important corrosion factors. The grain size of corrosion products due to O2 was fine while the grain size of corrosion products due to CO2 was course. As temperature rose, the corrosion rate of O2 reduced, while the corrosion rate of CO2 changed little when the temperature rose from 150 ℃ to 250 ℃. With the temperature changed from 250 ℃ to 300 ℃, the corrosion rate of both O2 and CO2 were raised sharply.