温度对API—X60管线钢HeS／CO2腐蚀行为的影响

Effects of Temperature on H2S/CO2 Corrosion Behavior of API-X60 Steel

利用高温高压反应釜模拟高含硫气田H2S／CO2共存环境，在流动溶液介质中进行腐蚀试验，辅以扫描电子显微镜和X射线衍射仪等研究手段，探讨了温度对API—X60管线钢H2S／CO2腐蚀行为的影响。结果表明，随着温度的升高，API-X60管线钢的腐蚀速率先升高后降低，腐蚀形态由局部腐蚀趋于全面腐蚀，高温区有点蚀倾向。低温时形成的腐蚀产物以马基诺矿型晶体和铁的单硫化物为主，随着温度的升高，腐蚀产物以层片状马基诺矿型晶体为主，并出现少量磁黄铁矿型晶体，高温区则以磁黄铁矿型晶体为主。低温区点蚀的发生是由于腐蚀产物附着力差导致其覆盖率降低，膜层覆盖处的阴极效应促进了局部腐蚀。

Flowing solution environments containing H2S/CO2 are simulated in a high temperature and high pressure autoclave. Corrosion behaviors of API-X60 pipeline steel are investigated with Scanning Electron Microscopy （SEM） and X-ray Diffraction methodology （XRD）. Effects of temperature on corrosion rate and products are discussed. The results show that corrosion rate of API-X60 steel increases at the beginning and then decreases with temperature increasing, and localized corrosion turns into general corrosion obviously, but pitting is observed at the higher temperature. Mackinawite and FeS composite form as corrosion product in low-temperature condition, with temperature increasing, the corrosion products are dominated by lamellar-type Mackinawite crystal and associated with a small amount of pyrrhotite crystal. However, pyrrhotite crystal becomes more dominated at higher temperature region. Poor adhesion of corrosion scale leads to a lower converging rate. Cathodic effect of scale promotes the localized corrosion and a faster anode reaction rate and rapid development of pitting will be achieved without blocked effect.