低Cr X70管线钢在多相流腐蚀环境中CO2腐蚀行为研究
CO2 Corrosion Behavior of Low Cr X70 Pipeline Steel in Oil-water-gas Multiphase Flow
孙锐艳1, 王立东2, 李 想3, 杨智超4
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作者单位：(1. 吉林油田公司 勘察设计院, 吉林 松原 138001; 2. 北京科技大学 冶金工程研究院, 北京 100083; 3. 浙江大学 电气工程学院, 浙江 杭州 310058; 4. 吉林油田乾安采油厂, 吉林 乾安 131400)
中文关键字：管线钢； CO2腐蚀； 多相流； 腐蚀产物膜
英文关键字：pipeline steel; CO2 corrosion; multiphase flow; corrosion product scale
中文摘要：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。
英文摘要：The oil-water-gas multiphase flow environment was simulated at high temperature and high pressure autoclave, the CO2 corrosion behavior of low Cr X70 pipeline steel was studied. The corrosion rate of the steel was calculated by the mass-loss method, and the micrograph, microstructure and component of the corrosion scales were observed and analyzed by scanning electron microscopy, energy dispersive spectrometer and X-ray diffraction techniques. The results show that, with the increase of environmental temperature, the average and pitting corrosion rates of X70 steel increase first and then decrease. The average corrosion rate and the pitting corrosion rate is up to the highest valum at 60 ℃ and 90 ℃, respectively. Cr exists mainly as amorphous compound Cr2O3 in specific layer of the corrosion scales which can hinder anionic to penetrate corrosion products and reach metal matrix, and gradually reduce the pitting corrosion led to Cl-. The proportion of FeCO3 in corrosion product scale increases gradually with the increase of environmental temperature.