X80管线钢在模拟液中的电化学行为

Electrochemical Behavior in Chinese Typical Simulated Soil Solutions of X80 Pipeline Steel

采用光学显微镜、扫描电子显微镜,透射电子显微镜系统地表征了X80管线钢的微观结构;采用2273恒电位仪研究了X80管线钢在库尔勒模拟土壤溶液、NS4溶液和鹰潭模拟土壤溶液中的电化学行为。结果表明,X80管线钢的微观结构由多边铁素体、针状铁素体和M/A组元组成;铁素体晶粒内存在位错胞和亚晶粒,铁素体晶界处有大量的位错缠结。X80管线钢在库尔勒模拟土壤溶液、NS4溶液和鹰潭模拟土壤溶液中的极化曲线只有活性溶解区,没有活化-钝化转变区。X80管线钢在库尔勒模拟土壤溶液中的腐蚀电流密度最大,在NS4溶液中次之,在鹰潭模拟土壤溶液中最小;X80管线钢在NS4溶液和鹰潭模拟土壤溶液中的腐蚀电流密度相差不大,但都远小于其在库尔勒模拟土壤溶液中的腐蚀电流密度。

The microstructure of X80 pipeline steel systemically was characterized by optical microscope, scanning electronic microscope, and transmission electron microscope, and studied electrochemical behavior of X80 pipeline steel in Ku＇erle simulated soil solution, NS4 solution and Yingtan simulated soil solution by Potentiostat/Galvanostat model 2273. It is shown that the microstructure of X80 pipeline steel is characterized by polygonal ferrite, acicular ferrite, and martensite--austenite （M/A） constituents. There are dislocation cells and sub--grains in a ferrite grain and a lot of dislocation tangled around ferrite grain boundaries. Only active region, and no active--passive transition region is found in polarization curves of X80 pipeline steel in Ku＇erle simulated soil solution, NS4 solution and Yingtan simulated soil solution. Corrosive current density of X80 pipeline steel is the largest in Ku＇erle simulated soil solution, and less in NS4 solutions, and the least in Yingtan simulated soil solution. Corrosive current density of X80 pipeline steel in Yingtan simulated soil solution is close to that of in NS4 solutions, but both of them much less than that of in Kfferle simulated soil solution.