Three-layer-PE corrosion control method for steel outer protective pipe

Abstract

The invention provides a three-layer-PE corrosion control method for a steel outer protective pipe. The method comprises the following steps that S1, the outer surface of the steel outer protective pipe is cleaned; S2, temperature control treatment is conducted on the outer surface of the steel outer protective pipe; S3, rust removal treatment is conducted on the outer surface of the steel outer protective pipe; S4, the outer wall of the steel outer protective pipe is sequentially coated with an epoxy powder coating, an adhesive layer and an outer anti-corrosion layer from inside to outside; S5, after three anti-corrosion layers of the steel outer protective pipe are coated, the three anti-corrosion layers at the end of the pipe are removed; and S6, process evaluation test and quality inspection are conducted on the three anti-corrosion layers. According to the three-layer-PE corrosion control method for the steel outer protective pipe, the steel outer protective pipe of each specification is coated with three corresponding anti-corrosion layers, a medium-frequency heating temperature control treatment mode is adopted for heating, the coating efficiency is improved, and an anti-corrosion pipe has the advantages of being smooth in surface, free of dark bubbles, pits, wrinkles and cracks, uniform in color, free of warped edges of the anti-corrosion pipe end and the like.

Description

technical field [0001] The invention belongs to the technical field of anticorrosion of steel outer protection pipes, and in particular relates to a three-PE anticorrosion method for steel outer protection pipes. Background technique [0002] At present, anti-corrosion steel pipes are mostly used in relatively important occasions, especially in petroleum, chemical industry, natural gas, thermal energy, water conservancy, roads, bridges and water conservancy, etc. Traditional solvent-based coatings have the following disadvantages: First, the formula components are not environmentally friendly and have harmful effects on the environment. Pollution; solvent-based coatings need to be diluted with xylene and other solvents during the coating process before spraying. Xylene has the characteristics of strong odor, flammability, and easy harm to the human body. The second is that the multi-layer spraying construction of liquid paint on the outer wall of the steel pipe is affected b...

AI Technical Summary

Problems solved by technology

[0002] At present, anti-corrosion steel pipes are mostly used in relatively important occasions, especially in petroleum, chemical industry, natural gas, thermal energy, water conservancy, roads, bridges and water conservancy, etc. Traditional solvent-based coatings have the following disadvantages: First, the formula components are not environmentally friendly and have harmful effects on the environment. Pollution; solvent-based coatings need to be diluted with xylene and other solvents during the coating process before spraying. Xylene has the characteristics of strong odor, flammability, and easy harm to the human body. The second is that the multi-layer spraying construction of liquid paint on the outer wall of the steel pipe is affected by the ambient temperature and the site, and the assembly line operation cannot be realized, and the construction efficiency is low; the ordinary anti-corrosion layer currently used on the steel outer protective pipe is generally two to Three-layer polyethylene anti-corrosion layer (3LPE), when the anti-corrosion steel pipe coated with anti-corrosion layer passes through areas with harsh environments such as mountains and rivers, it is very easy to cause large-scale damage to the anti-corrosion layer coated on the outside of the steel outer protection pipe , causing the anti-corrosion function of the steel pipe to weaken or fail, and the insulation resistivity and other properties of the anti-corrosion layer to drop sharply, which makes the maintenance cost of the steel pipe crossing high and difficult.

However, in the existing technology, the pipeline laying site is rough, the process conditions are poor, the construction environment is also very harsh, the forming time is long, the efficiency is low, and it is difficult to form a continuous and dense structural layer, and the anti-corrosion technology at the joint of the pipeline has a great impact on the overall quality of the pipeline. The anti-corrosion effect has a great influence, because it is related to the final anti-corrosion quality of the entire pipeline

No matter how good the quality of the 3LPE and 3LPP anti-corrosion coating in the prefabrication factory is, if the on-site patching effect is not good, it will lead to serious corrosion of the steel pipeline, shorten the service life of the buried pipeline, and even cause serious consequences such as leakage

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