N80套管钢在液固两相流中的冲刷腐蚀行为

Erosion-corrosion behavior of N80 casing steel in liquid-solid two phase flow

为更好地了解液固两相流对N80套管钢的冲刷腐蚀行为,采用旋转圆柱电极配合电化学工作站,通过对失重、动电位极化曲线、电化学阻抗谱等分析,结合电镜扫描,开展了流速和腐蚀时间对N80钢的冲刷腐蚀影响的试验研究。结果表明,两种因素下的极化曲线较平滑,均未出现明显的钝化区和过钝化区,为活性溶解反应,且均受阴极氧扩散控制;不同流速下的冲刷腐蚀速率先缓慢增加后大幅增加,临界流速2 m/s;低流速下以电化学腐蚀控制为主,高流速下以冲刷磨损控制为主;不同腐蚀时间下的冲刷腐蚀速率先缓慢减小后缓慢回升,在9 h达到最小,为冲刷磨损和电化学腐蚀混合控制。

In order to better understand the erosion-corrosion behavior of N80 casing steel in liquid-solid two phase flow,the rotating cylindrical electrode combined with the electrochemical workstation was applied.Based on the analyses of weight loss,potentiodynamic polarization curves and electrochemical impedance spectroscopy,together with electron microscope scanning,the experimental study on the influent factors of flow rate and corrosion time on erosion-corrosion of N80 steel were conducted.The results show that the polarization curves of the two influent factors are smooth,and there is no obvious passivation area or over-passivation area,which is active dissolution reaction and controlled by cathodic oxygen diffusion.At different flow speeds,the erosion-corrosion rate increases slowly at first,then increases significantly,and the critical flow speed is 2 m/s.Electrochemical corrosion is the main control at low flow speed,and erosion wear is the main control at high flow speed.The erosion-corrosion rate in different corrosion time decreases slowly and then rises slowly,reaching the minimum at 9 h,which is under the combined control of erosion wear and electrochemical corrosion.