两种低合金钢在深海环境下腐蚀行为规律研究

Corrosion Behaviors of Two Kinds of Low Alloy Steels in Deep-sea Environments

目的研究两种低合金钢材料在不同深度海水环境下的腐蚀行为规律。方法通过深海实海试验,研究10CrNi3MoV与E47两种船用低合金钢在1200、2000、3000 m深度海水环境下暴露0.5、2 a的腐蚀行为规律。借助于三维视频显微镜和XRD等技术,分别进行腐蚀形貌观察与腐蚀产物成分分析,结合腐蚀动力学数据,对比研究两者深海环境耐蚀性能的优劣。结果不同深度环境下,腐蚀产物分内外两层,锈层下表面形态相对平整,存在大量细小点蚀坑。随深度的增加,点蚀坑数量呈增加趋势。腐蚀初期,2000m腐蚀速率和点蚀深度最低,随暴露时间的推移,锈层中α-FeOOH的含量明显提升,腐蚀速率均呈下降趋势。结论10CrNi3MoV深海耐蚀性劣于E47,初期2000 m深海腐蚀性略差,深度增加有利于两者点蚀形核过程。随着时间的推移,锈层对基体具有一定的保护作用,点蚀纵深发展阻力增大。

Objective To investigate corrosion behaviors and rules of two kinds of low alloy steels in deep-sea environments. Methods Through the deep-sea field exposure test, corrosion behaviors of 10CrNi3MoV and E47 low alloy steels exposed for 0.5 a and 2 a at 1200 m, 2000 m and 3000 m depth of the sea were studied. With the help of 3D video microscope and XRD technology, the corrosion morphology observation and corrosion product composition analysis were done, and the corrosion kinetic data were also used to compare their corrosion resistance performance. Results The corrosion products had a two-layer sructure, and the surface under the rust layers was relatively flat, distributed with a lot of small pits. With the increase of depth, the number of pits increased. In the initial stage of corrosion, the corrosion rate and pitting depths were the lowest at 2000 m. With the exposure time went on, the content of α-FeOOH in the rust layer increased obviously, while the corrosion rate showed a decreasing trend. Conclusion The deep-sea corrosion resistance of 10CrNi3MoV is inferior to that of E47. In the early stage, deep-sea corrosion at 2000 m is slight for both, while the sea depth increase contributes to the pitting nucleation process. Over time, the rust layer has a certain protective effect on the substrate, and the resisitance of pitting growth to depth direction increases.