通过极化曲线、宏观腐蚀形貌、微观腐蚀形貌、腐蚀速率和三维点蚀形貌等,分析了X65钢在海水和淡水以及添加不同种类脱氧剂和缓蚀剂环境中的腐蚀行为。结果表明:在海水中添加缓蚀剂后,X65钢的自腐蚀电位最大正移量为11.6 mV,进一步添加脱氧剂后,其自腐蚀电位最大正移量为51.5 mV;随着浸泡时间的延长,试样表面生长出更为致密的腐蚀产物膜,最大点蚀速率从0.881 2 mm/a降至0.680 4 mm/a,该产物膜对试样表面起到保护作用;在海水中添加脱氧剂和缓蚀剂后,X65钢的最大点蚀速率下降至0.106 8 mm/a,进一步印证了脱氧剂和缓蚀剂的协同作用能更有效缓解溶解氧腐蚀,在X65钢海管封存过程中推荐添加脱氧剂+缓蚀剂HYH-80-SEA;常温下X65钢在海水中的腐蚀速率为淡水中的10倍,而在海水中添加脱氧剂和缓蚀剂HYH-80-SEA后,其腐蚀速率仍为淡水中的2~4倍。

The corrosion behavior of X65 steel in seawater and freshwater and the addition of different kinds of deoxidizers and corrosion inhibitors was analyzed by polarization curve, macro corrosion morphology, micro corrosion morphology, corrosion rate and three-dimensional pitting morphology. The results showed that the maximum positive shift of self-corrosion potential of X65 steel was 11.6 mV after adding corrosion inhibitor in seawater, and the maximum positive shift of self-corrosion potential was 51.5 mV after further adding deoxidizer. With the extension of immersion time, a denser corrosion product film grew on surface of the sample, and the maximum pitting rate decreased from 0.881 2 mm/a to 0.680 4 mm/a, which played a protective role on surface of the sample. After adding deoxidizer and corrosion inhibitor in seawater, the maximum pitting corrosion rate of X65 steel decreased to 0.106 8 mm/a, which further confirmed that the synergistic effect of deoxidizer and corrosion inhibitor could effectively alleviate dissolved oxygen corrosion. It was recommended to add deoxidizer+corrosion inhibitor HYH-80-SEA in the storage process of X65 steel sea pipe. The corrosion rate of X65 steel in seawater was 10 times higher than that in freshwater at room temperature, while the corrosion rate of X65 steel in seawater was still 2-4 times higher than that in freshwater after adding deoxidizer and corrosion inhibitor HYH-80-SEA.