A perforation leakage failure occurred in a natural gas pipeline in a gas production plant.In order to determine the cause of the pipeline leak failure,the appearance,chemical composition,metallographic structure,open circuit potential,mechanical properties and microscopic morphology of the leaked steel pipe were analyzed.The results show that the chemical composition of the leaked steel pipe ma-terial meets the requirements of GB/T 8163-2018 standard,and the tensile properties of the material meet the requirements of GB/T 8163-2018 standard.The leakage of the pipeline is caused by the formation of a large cathode and a small anode corrosion battery between the deposition of solid insoluble matter in the transported natural gas and the exposed metal on the inner wall of the pipeline steel pipe,which causes the anode dissolution of the exposed metal.In addition,because the solid particles in the fluid in the steel pipe erode the inner surface of the steel pipe,the metal anode on the inner surface of the steel pipe is quickly dissolved,so that the wall of the steel pipe is grad-ually thinned,and eventually the local corrosion perforation of the steel pipe wall occurs.
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