高压气井用双相不锈钢的组织特征和耐蚀性
Microstructure and Corrosion Resistance of Duplex Stainless Steels Used for High Pressure Gas Wells
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摘要: 采用金相显微镜、高温高压腐蚀试验和标准点蚀及缝隙腐蚀试验, 研究了UNS S32205和UNS S32750两种双相不锈钢的多相组织特征和在模拟气田腐蚀环境中的腐蚀行为; 并采用X射线能谱仪、X射线衍射等技术和X射线光电子能谱分析了表面钝化膜。结果表明, 两种双相不锈钢均有近等比例的铁素体(α)相和奥氏体(γ)相, 具有较好的耐均匀腐蚀和局部腐蚀性能, 但UNS S32750钢的耐腐蚀性能优于UNS S32205钢, 而后者产生了轻微的局部腐蚀, 局部腐蚀速率在可接受范围内。Abstract: 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.