Because the coating of the polyethylene three-layer structure anti-corrosion steel pipe is coated with high-density polyethylene (HDPE) by fusion winding process, the pipe has strong corrosion resistance, and does not need anti-corrosion layer anti-corrosion, waterproof, insulation, and the use temperature can reach 70 °C, which is the most ideal gas, water transmission, buried cable casing, sewage treatment, seawater desalination pipe in China, and is also a pipeline anti-corrosion material commonly used all over the world.
The anti-corrosion performance of polyethylene three-layer structure anti-corrosion steel pipe is related to the material, processing technology, spraying process and other factors of the steel pipe. Among them, the choice of spraying material is the key. Commonly used spraying materials are epoxy powder, polyolefin powder, etc. Epoxy powder has high adhesion and corrosion resistance, but ** is higher;Polyolefin powder** is relatively low, but has weak adhesion. Therefore, it is necessary to select the appropriate spraying material according to the specific use environment and requirements.
The production process of polyethylene three-layer structure anticorrosive steel pipe mainly includes the following steps:
1.Steel pipe pretreatment: The surface of the steel pipe is shot blasted and rust removed to remove impurities such as oil stains and rust stains on the surface, and improve the adhesion and durability of the coating.
2.Primer: Apply a layer of primer on the surface of the steel pipe to fill in and improve the adhesion and corrosion resistance of the coating.
3.Spraying the middle coat paint: Before the middle coat is dried, the three layers of co-extruded polyethylene are extruded and wound on the surface of the steel pipe, and a certain pressure and temperature are maintained to make the polyethylene melt on the surface of the steel pipe.
4.Cooling: The surface temperature of the steel pipe is reduced below the melting point of the polyethylene by cooling water, so that the polyethylene layer is fixed on the surface of the steel pipe.
5.Topcoat: A topcoat is applied to the surface of the steel pipe to protect and decorate.
The advantages of three-layer polyethylene coated steel pipes include:
1.High corrosion resistance: Due to the use of high-density polyethylene (HDPE) in the coating, it is highly corrosion-resistant and able to resist various chemicals.
2.Good insulation: The pipe has good insulation properties and can withstand the insulation protection of high voltage.
3.Reliable connection: Reliable connection methods such as hot melt connection or electric fusion connection are adopted to ensure the reliability of pipeline connection.
4.Convenient construction: Because the pipe is lightweight, easy to handle and install, the construction is convenient and fast.
5.Long service life: Because the pipe has good corrosion resistance and insulation, it has a long service life and can keep the pipe in normal use for a long time.
The application of three-layer polyethylene coated steel pipes is very wide, including:
1.Gas pipelines: used for the laying and repair of urban gas pipelines, which can ensure the safe transmission and storage of gas.
2.Water supply pipeline: It is used for the transportation of tap water, industrial water and other water supply pipelines, which ensures the safety and hygiene of water quality.
3.Buried cable casing: used for the laying and protection of buried casing such as power cables and communication optical cables.
4.Sewage treatment: It is used for the transportation and discharge of sewage treatment pipelines, which can ensure the normal operation of sewage treatment.
5.Seawater desalination: It is used for the transportation and storage of seawater desalination pipelines, which can ensure the quality and safety of seawater.
In a word, as a new type of pipeline anti-corrosion material, three-layer polyethylene coated steel pipe has the advantages of good corrosion resistance, insulation, connection reliability and long service life, so it has been widely used and developed. With the continuous progress of science and technology and the continuous expansion of application fields, the pipe will play an increasingly important role.