The corrosion forms of seamless buried pipes are divided into local corrosion and uniform corrosion, which have the advantage of local corrosion and the greatest harm. In the process of soil erosion, pipelines are mainly electrochemically dissolved, and the formation of corrosive cells leads to pipeline perforation and corrosion. Corrosion between anode and cathode batteries can also form corrosive batteries to corrode steel, which can be divided into micro-batteries and macro-batteries. The so-called corrosion of micro-batteries refers to the corrosion caused by the separation of micro-batteries from the anodes and cathodes of several microns. Its shape is very uniform, also known as uniform corrosion. Because the distance between the micro-anode and the cathode is very close, the corrosion rate of the micro-battery does not depend on the resistivity of the soil, but only on the micro-process of the anode and the cathode. Micro-corrosion of buried steel pipe.



The so-called macrocell corrosion refers to the current action, which means that the pipeline is corroded by anode and cathode areas several centimeters or even several meters away. Macro battery corrosion is also called local corrosion. In addition to anode and cathode electrode processes, the corrosion rate of macrocells is related to soil resistivity, because the anode and cathode regions account for a large proportion of the total resistance of corroded cell circuits. Large cell erosion rate reduces soil resistivity. This is due to large cell erosion in buried pipelines or patchy corrosion on the surface, which can be very destructive.