渗铬P110钢在CO2饱和模拟油田采出液中的耐蚀性

摘要

In order to improve the surface properties of P110 oil casing tube steel and meet the service requirements in oilfield environment,the chromizing treatment was performed for P110 steel with an embedding method.The surface morphology,microstructure,element distribution and phase structure of the chromizing layer were analyzed and characterized with scanning electron microscope（SEM）,energy dispersive spectrometer（EDS） and X-ray diffractometer（XRD）.The electrochemical testing technique was used to measure the open circuit potential,polarization curve and alternating current impedance spectroscopy of P110 steel and its chromizing layer in CO2-saturated simulated oilfield produced liquid.The results reveal that the chromizing layer is composed of Cr23C6,Cr7C3 and（Cr,Fe）7C3 phases,and is uniform and continuous.In comparison with the P110 steel,the chromizing layer exhibits higher open circuit potential and charge transfer resistance as well as lower current density and corrosion rate.The chromizing process improves the corrosion resistance of P110 steel significantly.%为了提高P110油套管钢的表面性能,以满足其在油田环境下服役的要求,采用包埋法对P110钢进行渗铬处理.借助扫描电镜、能谱仪和x-射线衍射仪,对渗铬层的表面形貌、显微组织、成分分布和相结构进行了分析和表征,利用电化学测试技术测定P110钢及其渗铬层在CO2饱和模拟油田采出液中的开路电位、极化曲线和交流阻抗谱.结果表明：渗铬层由Cr23C6、Cr7C3和（Cr,Fe）7C3等相构成,且均匀、连续,与P110钢相比,具有更高的开路电位和电荷转移电阻及更低的电流密度和腐蚀速率.渗铬处理显著提高了P110钢的耐蚀性.