Microstructure and Corrosion Resistance of Duplex Stainless Steels Used for High Pressure Gas Wells

The microstructure and corrosion behavior of duplex stainless steels UNS S32205 and UNS S32750 were studied by microscopy, high tempercture and high pressure (HTHP) test, pitting corrosion test and crevice corrosion test. The passive film was analyzed by energy dispersive X-ray spectrometer, X-ray diffraction and X-ray photoelectron spectroscopy. The results showed that these two steels had nearly equal proportion double phases of α-ferrite and γ-austenite, uniform corrosion and localized corrosion performance of the two duplex stainless steels were well. The corrosion resistance of UNS S32750 steel is better than UNS S32205 steel. The localized corrosion rate of UNS S32205 steel is acceptable.