目的 揭示45#钢、3Cr钢在高温高压CO2/O2/SO2体系中的腐蚀行为及力学性能规律，为新疆油田注蒸汽管道的安全运行提供理论支撑。方法 基于注蒸汽管道现场运行工况，结合高温高压釜、结合扫描电子显微镜、3D显微镜、X射线衍射仪(XRD)等手段，进行失重测试、产物表征及拉伸测试试验。结果 随着温度(100~250 ℃)升高，45#钢、3Cr钢的腐蚀速率呈减小的趋势;随着O2含量(物质的量分数，0~3%)升高，45#钢、3Cr钢的腐蚀速率呈先增大后减小的趋势，在O2含量2%~3%时腐蚀受到抑制。XRD测试结果表明45#钢在CO2/O2/SO2体系中腐蚀产物主要包括FeSO4.H2O、FeCO3、Fe2O3，3Cr钢的腐蚀产物主要有Cr2O3、FeSO4.H2O、FeCO3、Fe2O3。3D显微镜结果显示45#钢基体表面存在较为明显的局部腐蚀缺陷，3Cr钢未出现局部腐蚀现象;力学性能结果显示45#钢腐蚀后抗拉强度减小1.36%，延伸率减小6.85%，3Cr钢腐蚀后抗拉强度减小0.39%，延伸率减小21.34%。结论 在高温高压CO2/O2/SO2环境中，SO2在腐蚀过程中占据主导地位;高温(100~250 ℃)下腐蚀产物膜致密，抑制腐蚀;O2参与阴极反应，在低浓度氧(0~2%)时腐蚀产物膜被破坏从而促进腐蚀，高浓度氧(2%~3%)时钢材基体钝化抑制腐蚀;腐蚀后钢材力学性能退化，腐蚀对钢材延伸率影响较大，对抗拉强度影响较小。

In order to reveal the corrosion behavior and mechanical properties of 45# steel and 3Cr steel in the high temperature and pressure CO2/O2/SO2 system, and provide theoretical support for the safe operation of steam injection pipelines in Xinjiang Oilfield. Based on the on-site operating conditions of the steam injection pipeline, combined with high temperature autoclave, combined with scanning electron microscope, 3D microscope, X-ray diffractometer (XRD) and other means, weight loss test, product characterization and tensile test are carried out. With the increase of temperature (100-250 ℃), the corrosion rate of 45# steel and 3Cr steel shows a decreasing trend; with the increase of O2 content (0-3mol%), the corrosion of 45# steel and 3Cr steel rate first increases and then decreases, and the corrosion is inhibited when the O2 content is 2mol%-3mol%. The XRD test results show that the corrosion products of 45# steel in the CO2/O2/SO2 system mainly include FeSO4.H2O, FeCO3, Fe2O3, and the corrosion products of 3Cr steel mainly include Cr2O3, FeSO4.H2O, FeCO3, and Fe2O3. The 3D microscope results show that 45# there are obvious local corrosion defects on the surface of the steel substrate, and 3Cr steel does not appear local corrosion; the mechanical properties show that the tensile strength of 45# steel after corrosion is reduced by 1.36%, the elongation is reduced by 6.85%, and the tensile strength of 3Cr steel after corrosion Reduced by 0.39%, elongation reduced by 21.34%. In the high temperature and pressure CO2/O2/SO2 environment, SO2 dominates the corrosion process; the corrosion product film is dense at high temperature (100-250 ℃), which inhibits corrosion; O2 participates in the cathodic reaction, and in the low concentration of oxygen (0-2mol%), the corrosion product film is destroyed to promote corrosion. When high concentration oxygen (2mol%-3mol%), the steel matrix is passivated to inhibit corrosion; after corrosion, the mechanical properties of the steel are degraded, and corrosion has a greater impact on the elongation of the steel. The tensile strength is less affected.