Abstract

Stray current corrosion has become one of the important failure factors of buried steel pipelines. In this paper, the propagation law of stray current in soil was simulated and analyzed based on Comsol Multiphysics software, and the relationship between the decay law of stray current potential and soil resistivity was obtained. The effect of the damaged area of the anticorrosive layer, soil oxygen concentration, soil pore saturation and other factors on the pipeline ground potential at the inflow and outflow point of stray current is simulated and analyzed. The damaged area of the anticorrosive layer has a more obvious effect, the current density at the defect edge is higher than that at the center, and the outflow stray current density at the damaged point of the anticorrosive layer increases with the decrease of the damaged area of the anticorrosive layer, and the corrosion becomes more intense. Oxygen is mainly consumed at the inflow of stray current, and oxygen reduction reaction occurs. With the increase of soil porosity, the diffusion coefficient of oxygen decreases, while the conductivity of soil electrolyte increases. As the influence of soil electrolyte conductivity is larger than that of oxygen diffusion coefficient, the corrosion becomes more intense with the increase of soil porosity. The research in this paper has important guiding significance for further understanding of stray current corrosion mechanism of buried steel pipelines.