目的 确定 API X65、 316L 不锈钢及 inconel625 相互偶接后的电偶腐蚀风险。 方法 采用电化学测试、标准电偶腐蚀评价实验和腐蚀模拟实验对电偶腐蚀进行分析研究。 结果 在模拟地层水中，经过电化学测试， X65 的自腐蚀电位在-0.75 V 左右， 316L 和 625 的电位在-0.35 V 左右。对于标准电偶腐蚀评价实验，敞口溶液及 CO2 分压分别为 100 kPa 和 500 kPa 的溶液中， X65 与 316L 之间的电偶电流最大，其次是 X65 与 625， 316L 和 625 之间的电偶电流最小，几乎为零。通过电偶腐蚀模拟试验可知， X65 与316L 或 625 偶接，都发生了明显的电偶腐蚀，而且 X65 侧靠近焊接接头位置发生了严重的沟槽腐蚀，未偶接异金属时 X65 的平均腐蚀速率为 1.24 mm/a，异金属接触导致的电偶腐蚀使 X65 的腐蚀速率增加，X65 与 316L 偶接后的平均腐蚀速率为 1.49 mm/a， X65 与 625 偶接后的平均腐蚀速率为 1.75 mm/a。 X65与 316L 偶接后的局部腐蚀速率最大为 16.8 mm/a， X65 与 625 偶接后的局部腐蚀速率高达 26.4 mm/a，由于电偶腐蚀导致的局部腐蚀速率要比 X65 的自腐蚀速率超出十几倍。 X65 与 316L 偶接的电偶腐蚀的速率要比 X65 和 625 偶接的大， 316L 和 625 间几乎没有电偶腐蚀发生。 结论 X65、 316L 和 625 间偶接的电偶腐蚀风险大于 X65 与 316L 的， 316L 和 625 间偶接的电偶腐蚀风险较小。

Objective To determine the galvanic corrosion risk among API X65, 316L and inconel 625. Methods Electrochemical corrosion test, standard galvanic corrosion evaluation experiment and simulation experiment were carried out to analyze the corrosion risk. Results The corrosion potential of X65 was around -0.75 V, while that of 316L and 625 potential was both around -0.35 V. For standard galvanic corrosion evaluation experiment, in the open solution or 100 kPa and 500 kPa CO2 solution, the galvanic current of X65-316L was the largest, followed by X65-625 and then 316L-625. Galvanic corrosion occurred when X65 met either 316L or 625. For simulation experiment, obvious galvanic corrosion occurred among X65, 316L and 625. There was a serious groove corrosion near the weld joint position in X65. The corrosion rate of X65 without galvanic corrosion was 1.24 mm/a. The galvanic corrosion increased this value. The average galvanic corrosion rate of X65-316L was 1.49 mm/a and that of X65-625 was 1.75 mm/a. The local galvanic corrosion rate of X65-316L was 16.8 mm/a and that of X65-625 was 26.4 mm/a, which was over ten times as high as the corrosion rate of X65 without galvanic corrosion. The galvanic corrosion rate of X65 and 316L was larger than that of X65 and 625. There was almost no galvanic corrosion between 316L stainless steel and 625 nickel base alloy. Conclusion Galvanic corrosion risk between X65 and 316L was larger than that between X65 and 625. Galvanic corrosion risk between 316L and 625 was very small.