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利用高温高压反应釜模拟油田多相流腐蚀环境,对低Cr X70管线钢CO2腐蚀行为进行了研究。采用失重法计算腐蚀速率,利用SEM、EDS、XRD等手段观察和分析了腐蚀产物膜的形貌、结构和成分。结果表明:随着腐蚀环境温度的升高,X70管线钢平均腐蚀速率和点蚀速率的变化趋势均是先增大后减小,在60℃时平均腐蚀速率达到最大值,而在90℃时点蚀速率达到最大值;基体中的Cr容易生成Cr2O3在金属表面沉积,可以有效阻碍阴离子穿透腐蚀产物膜到达金属表面,大大减少Cl-导致的点蚀;随着环境温度的升高,FeCO3在腐蚀产物膜中占的比例也随温度的升高而增加。
The high temperature and high pressure reactor was used to simulate the multiphase corrosive environment in the oilfield and the CO2 corrosion behavior of low Cr X70 pipeline steel was studied. The corrosion rate was calculated by weight loss method. The morphology, structure and composition of corrosion film were observed and analyzed by SEM, EDS and XRD. The results show that with the increase of corrosion temperature, the average corrosion rate and pitting corrosion rate of X70 pipeline steel first increase and then decrease, and the average corrosion rate reaches the maximum at 60 ℃. At 90 ℃ Pitting rate reaches the maximum; Cr in the matrix is easy to generate Cr2O3 deposition on the metal surface, which can effectively prevent the anion from penetrating the corrosion product film to the metal surface, greatly reducing the pitting corrosion caused by Cl-; as the ambient temperature increases, FeCO3 The proportion of corrosion products in the film also increases with increasing temperature.