10CrNi3MoV船用钢港口环境腐蚀行为对比研究

Comparison on Marine Corrosion Behavior of 10CrNi3MoV Steel in Typical Harbors of China

目的对比研究10CrNi3MoV船用钢在我国黄海、东海和南海海域具有代表性的港口海水环境中的腐蚀行为。方法在青岛、舟山和三亚港口进行10CrNi3MoV船用钢的实海暴露实验,通过腐蚀形貌观察、腐蚀速率和点蚀深度测量,结合各海域环境因素的监测和腐蚀产物成分的XRD分析,研究材料暴露0.5a的腐蚀规律和腐蚀机制。结果 10CrNi3MoV钢在青岛港口主要发生均匀腐蚀,在舟山和三亚港口以点蚀为主要腐蚀形式。10CrNi3MoV钢腐蚀速率受温度、盐度、溶氧量和泥沙冲刷综合作用的影响,随港口纬度的降低,材料腐蚀速率增大。附着海生物是影响10CrNi3MoV钢点蚀的重要因素,材料在附着率高的三亚和舟山港口具有更高的点蚀深度。结论附着区与非附着区形成的电偶效应使阴阳极反应界面分离,具有保护性的α-FeOOH的阴极去极化加快了附着海生物闭塞区的阳极溶解。

Objective To comparatively research corrosion behaviors of 10CrNi3MoV low alloy steel in the marine environment of typical harbors of the Huanghai Sea, the East China Sea and the South China Sea. Methods The field corrosion tests of 10CrNi3MoV low alloy steel were performed in the harbor seawater of Qingdao, Zhoushan and Sanya. The observation of the corrosion morphology and the measurement of the corrosion rate and pitting depth were conducted. Combined with the monitoring of the marine environment factors and the XRD results of the corrosion product, the corrosion mechanism of 10CrNi3MoV steel was discussed. Results 10CrNi3MoV steel experienced mainly general corrosion in the Qingdao harbor, while pitting was the major corrosion form in Zhoushan and Sanya. The corrosion rate of the steel was influenced under the mixed effect of seawater temperature, salinity, dissolved oxygen concentration and sediment erosion. With the decrease of the harbor latitude, the corrosion rate of the steel increased. The attached fouling organism was a key factor that affected the pitting behavior of the steel. The steel had higher pitting depth in the harbor of Zhoushan and Sanya where the adhesion rate of the fouling organism was high. Conclusion The galvanic couple effect formed between the adhesion region and the non-attached region caused the separation of the interface between the cathodic and anodic reaction. The anodic dissolution in the occluded area beneath the attached organism is accelerated by the cathodic depolarization of the protective α-FeOOH product.