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　　China has built 68,000 km oil and gas pipelines, in which large diameter steel pipes are often stored in the open air due to engineering suspension, construction surplus, engineering reserve and other factors. If the open-air storage time is long, there will be problems such as corrosion pits, wall thickness thinning after corrosion, anticorrosive coating edge warping, anticorrosive coating aging and so on, which will lead to the degradation of the use of carbon steel pipes, rejection or re-treatment, resulting in waste of resources.

　　The main reason is that the ASTM API 5L Black Carbon Steel Pipe body has no cover, no cover protection is ideal, no support, part of the pile-up layer is too many problems, and most coastal areas belong to marine climate, annual rainfall, air humidity, carbon steel pipe and steel pipe contact parts of water accumulation. The protection method should be:

　　1. If bare or anticorrosive carbon steel pipes need long-term storage, opaque cover should be used to protect the pipes from corrosion, aging of anticorrosive coating and warping.

　　2, covering should be strong and durable, prevent long time sun and rain, rot and leakage.

　　3. When the carbon steel pipe is covered, the surface of the steel pipe should be ventilated to prevent water vapor from being vaporized and collect on the surface.

　　4. When the carbon steel pipe is stored, there should be a support and a certain distance from the ground to ensure that the steel pipe is ventilated.

　　5. After stacking and storing, the pipe end protector should be removed to avoid moisture gathering at the interface between the pipe end protector and the carbon steel pipe and difficult to volatilize.

　　6. Pay attention to the number of layers of carbon steel pipes in storage, so as to avoid the local stress at the end of the pipe caused by too many layers, thus causing radial plastic deformation of steel pipes and damage to the anticorrosive coating.

　　7. Avoid contacting with pollutants such as oil and copper when storing steel pipes.

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