Study on Electrochemical Corrosion of Nb Microalloy Steel
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摘要: 为了研究含Nb微合金化高速重轨钢的腐蚀性能，在某厂生产的重轨钢U75V （Cr含量为0．45%）的基础上，以不同Nb含量的试验重轨钢为研究对象，采用恒电位测量法，利用CorrView软件对极化曲线进行拟合，对试验钢电化学腐蚀规律进行分析，探究造成高速铁路重轨钢腐蚀的主要原因。研究结果表明：Nb的加入使氧化层更加致密，有利于钢耐蚀性的提高，含Nb 0．028%的2－Nb试验钢的耐蚀性最好，适量的Nb能提高基体的自腐蚀电位并能使氧化层更致密，从而提高钢的耐蚀性；含Nb 0．028%的2－Nb试验钢的自腐蚀电流密度均低于其他三种试验钢，说明其耐蚀性能最好；对不同腐蚀时间氧化层的物相分析表明，添加合金元素Nb有利于α-FeOOH的快速形成和含量的增加，Nb加入量为0．028%的试验钢的α-FeOOH/γ-FeOOH值比其他三种钢高，表明其耐腐蚀性能相对更好。因此，本研究为重轨钢的成分优化和新钢种的设计提供理论依据。Abstract: In order to study corrosion properties of Nb microalloying high speed rail steel, heavy rail U75V steel (Cr 0.45%) with different Nb content had been investigated.The main causes of corrosion of high speed rail steel are explored by fitting curve analysis using CorrView electrochemical software based on constant potential measurement.The results show that the addition of Nb produces much more compact oxide layer, which is conducive to improvement of steel corrosion resistance.Nb can improve self-corrosion potential of steel substrate and can make oxide layer more dense. Corrosion current density of test steel containing 0.028% Nb is lower than the other test steel.Phase analysis of rust layer with different corrosion time shows that adding Nb is conducive to fast formation and quantity of α-FeOOH. α-FeOOH/γ-FeOOH ratio of test steel containing 0.028% Nb is higher than that of the other three kinds of steel. Therefore, this study provides a theoretical basis for composition optimization of high speed rail steel.
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Key words:
- high speed rail steel /
- Nb microalloying /
- corrosion rate /
- electrochemical
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