Exploration of Initial Corrosion Behaviors of U71Mn Steel Rails in Neutral NaCl Solution

Abstract

In order to study the relationship between the corrosion behavior of steel rails and the concentration and corrosion time of NaCl solution, U71Mn steel rails were taken as the object, and the initial corrosion behavior and mechanism of steel rail materials immersed in neutral NaCl solutions (different concentrations of 1.0%, 2.0%, 2.5%, 3.5%, 4.0% and 5.0%) for 144 h, and in neutral 3.5% NaCl solutions for various immersion times (12, 48, 96, 144, 192, 288 h) were investigated by full immersion test and electrochemical tests.Results showed that the average corrosion rate of initial steel rail materials was positively correlated with NaCl concentration and immersion time.With the increase of NaCl concentration, the Ecorr of the steel rail specimen moved negatively from－0.651 V to－0.717 V, and the Jcorr increased from 5.71 μA/cm2 to 67.48 μA/cm2.With the increase of corrosion time, the Ecorr of the steel rail specimen moved negatively from－0.692 V to－0.720 V, and the Jcorr increased from 7.54 μA/cm2 to 74.59 μA/cm2.Furthermore, the reduction of corrosion products γ-FeOOH could destroy the original stable rust layer structure, and finally causing the acceleration of corrosion.

Keywords

• u71mn steel rail； total immersion test； neutral nacl solution； corrosion behavior； electrochemistry