Effect of DC Stray Current on Corrosion Behavior of Q235 Steel in Red Soil

Under the interference of simulated DC current, the change law of potential to ground and corrosion behavior of grounding material Q235 steel in Jiangxi red soil environment were studied. The morphology and composition of corrosion products on the surface of the sample were analyzed by scanning electron microscope, energy dispersive spectrometer and X-ray diffractometer. The initial potential offset and stable potential offset were correlated with the corrosion rate obtained by weight loss method. The results show that under the DC current interference of different current densities, the anode-to-ground potential decreased first, then increased slowly, and finally tended to be stable. Under DC interference, the surface of the sample showed the characteristics of localized corrosion. The corrosion products were layered, loose and easy to fall off, and their main components were Fe₂O₃ and FeOOH. The initial potential offset and stable potential offset were linearly related to the measured corrosion rate. Under the experimental conditions, the corrosion rate of Q235 steel grounding material could be indirectly predicted by measuring the anode-to-ground potential.