Abstract: The X70 and X80 steel electrochemical specimens were soaked shortly in NS4 solution which was simulated as a typical neutral soil environment. After that, ulcerlike, loose and easilyfalling rust spots were found on them. Shallow corrosion pits occurred in larger rust spots. The electrochemical behaviors of specimens were investigated with polarization curve method and electrochemical impedance scan method. The results show that the rust spot increased corrosion trend of metals and accelerated the corrosion rate. This was due to the imperfection and separation of the early rust spots reduced the metalenvironmental polarization resistance. The roughness of the surface increased the working area of the specimens and the corrosion current.

Key words: X70 steel, X80 steel, Neutral soil environment, Rust spot, Early corrosion

摘要： 采用 N S 4典型中性土壤模拟溶液模拟中性土壤环境, 将 X 7 0和 X 8 0管线钢电化学试件在模拟溶液
中进行短期浸泡, 发现溃疡状锈斑均匀分布在试件的工作表面, 锈迹疏松易脱落, 微观呈现颗粒状形貌, 面积较大的
锈斑处出现浅腐蚀坑。对带锈件和不带锈件进行了极化曲线、 交流阻抗等电化学实验并进行了对比。对比结果发
现, 金属界面早期锈斑的产生加重金属的腐蚀, 加快腐蚀速率。这是因为早期锈斑的不完整性与稀疏性降低金属基
体与腐蚀环境电化学反应的极化电阻, 其粗糙的表面增加试件的工作面积, 增大腐蚀电流。

关键词: X 7 0钢 ,  , X 8 0钢 ,  中性土壤 ,  , 锈 ,  , 早期腐蚀