Prediction of interference current of buried pipeline and study on corrosion of Q235A steel

Abstract

Interference current will cause severe electrochemical corrosion to buried pipes. However, the interference current flowing into the buried pipeline cannot be directly measured, and the influence of interference current on the corrosion of the buried pipeline cannot be directly observed. In this paper, the combined analysis methods of finite element analysis, partial least square method and electrochemical measurement technique are used to predict the interference current of buried pipeline and to study the effect of dynamic interference current and chloride ion concentration on the corrosion of Q235A steel. The prediction results show that increasing the input variables of the prediction model and changing the position of the input variables can effectively improve the accuracy of the model. Electrochemical measurements show that an increase in chloride ion concentration increases the corrosion current density in the polarization curve of Q235A steel and decreases the capacitive reactance arc radius in the electrochemical impedance spectroscopy. In addition, on the basis of the rail-to-ground potential monitoring points in the actual project, the number of rail-to-ground potential monitoring points was increased to improve the prediction accuracy of the buried pipeline interference currents, which indicates that the analysis method is an effective way to monitor and evaluate the influence of stray currents on the corrosion of buried pipelines.