采用电化学性能测试、半浸泡试验及SEM、EDS分析研究了铬含量对薄壁高强度桩管钢耐腐蚀性能的影响。结果表明, 试样在3.5%盐溶液中一直处于活化状态; 随着铬含量增加, 薄壁高强度桩管钢试样自腐蚀电位相差不大, 但腐蚀电流密度降低, 电荷转移电阻增大; 试样在盐溶液-大气界面处腐蚀最为剧烈。随着铬含量的增加, 钢的耐蚀性不断提高, 当铬质量分数为2%时, 试样耐蚀性最好, 年腐蚀速率为0.023 4 mm/a。铬元素在锈层中出现富集现象, 但在液-气界面区和浸泡区表现出不同的特征: 铬元素在浸泡区富集于与基体接触的内锈层区, 而在液-气界面区富集于远离基体的外锈层区。

Effects of Cr on corrosion behavior of thin-wall high strength pile pipe steels were studied with electrochemical test, half-immersion, SEM and EDS. The results showed that the specimens were activated in 3.5% NaCl solution, the corrosion current density reduced with the increase of Cr while the charge transfer resistance increased. The most serious corrosion area of thin-wall high strength pile pipe steel specimens in half-immersion tests was the interface between NaCl solution and air. Corrosion resistance of the specimens was improved with the increase of Cr content. The specimen with 2% Cr had the best corrosion resistance, and the corrosion rate was 0.0234mm/a. Cr element was enriched in the rust layer in different ways at the immersion area and the interface area between NaCl solution and air. Cr was enriched in the inner area of rust layer contacting with the substrate at the immersion area, while enriched in the outer area of rust layer at the interface area between NaCl solution and air.