Effect of magnetic field characteristics on dynamic stray current corrosion behavior of U75V steel

Abstract

The leakage of stray current (SC) in urban rail transit systems represents a prevalent engineering issue that contributes to electrochemical corrosion of rails, thereby posing significant safety risks and economic losses. Currently, the corrosion behavior of rails and its influencing factors under complex electromagnetic field conditions remain poorly understood. To investigate this issue further, this study employs a combined approach involving finite element simulation and experimental techniques. Initially, the characteristics of the magnetic field distribution during the rail return current process are analyzed. Based on this analysis, an experiment is planned to explore the electrochemical corrosion characteristics of U75V steel subjected to the combined effects of dynamic SC and magnetic fields. The corrosion behavior of U75V steel under static and dynamic magnetic fields is systematically analyzed using techniques such as polarization curves, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The results indicate that the size, direction, and dynamic characteristics of the magnetic field significantly influence the corrosion rate and the morphology of corrosion products. Notably, when the static magnetic field strength is 80 mT, the corrosion rate reaches its peak value. Furthermore, the influence of magnetic field strength on corrosion current density and charge transfer resistance demonstrates a distinct nonlinear behavior, thereby promoting the formation of Fe₂O₃ and Fe₃O₄. In conclusion, the findings of this study establish a solid theoretical foundation for understanding the corrosion behavior of rails in complex electromagnetic environments.