Plastic-coated steel pipe is a new type of pipeline material recently developed in China. It adopts a plastic-coated protective layer inside and outside. The middle of the large-diameter plastic-coated steel pipe is a composite structure of reinforced welded steel pipe or seamless pressure-bearing steel pipe. The defects of easy rust, corrosion, high pollution, low strength and easy deformation of plastic pipes integrate the common advantages of steel pipes and plastic products, and are environmentally friendly products promoted and used by the country. Plastic-coated steel pipe is also called plastic-coated composite pipe, which is a kind of steel-plastic composite pipe. Its process is to melt a layer of polyethylene (PE) resin and epoxy (EP) with a thickness of 0.5 ~ 1.0mm on the inner wall of the steel pipe. The steel-plastic composite pipe is composed of powder, non-toxic polypropylene (PP) or non-toxic polyvinyl chloride (PVC) and other organic substances. It not only has the advantages of high strength, easy connection, and resistance to water impact of steel pipes, but also overcomes the advantages of steel pipes. It is easy to be corroded, polluted, fouled and plastic pipe is not strong in contact with water. The design life can be up to 50 years. Its connection methods are threaded, welded, flanged and clamped. The main specifications are Φ15 -Φ 1200, and larger diameters can also be customized.

The inner and outer plastic-coated composite steel pipe is a steel-plastic composite pipe made of welded steel pipe as the base material, using sandblasting chemical double pretreatment, preheating, internal and external coating, curing, post-treatment and other processes. It has excellent comprehensive performance, strong corrosion resistance and mechanical properties, good chemical resistance and water resistance, and has the functions of drag reduction, corrosion resistance, compression resistance, and antibacterial. It is generally not restricted by the conveying medium, and the plastic-coated layer has a strong bonding force with steel.

Coating material: Epoxy resin (EP) is suitable for working environment below 80℃, steel pipe coating has extremely high adhesion, its coating has high hardness, good impact resistance and good chemical corrosion resistance. Plastic-coated steel composite pipes are much better than plastic-lined, rubber-lined, hot-dip galvanized pipes, etc. The process mainly includes electrostatic spraying and hot dipping. Generally, electrostatic spraying is suitable for pipe requirements in any field. Hot dipping can be used in fields such as fire protection and cable threading pipes.

There are also many details to be paid attention to in the processing technology, such as the coating layer should be uniform, every place should be sprayed, and the control of the dipping time, etc., if you want to make the product the first choice, you must choose high-quality epoxy or poly Ethylene powder then needs advanced process technology, and finally advanced equipment support. Epoxy resin-coated composite steel pipe is based on steel pipe, plastic powder is used as the coating material, and a plastic layer is melt-coated on the inner surface, and a plastic layer or other materials are melt-coated on the outer surface. Steel-plastic composite product with anti-corrosion layer.

Plastic-coated steel pipes are divided into polyethylene-coated steel pipes and epoxy-coated steel pipes according to different inner coating materials. The product mark consists of the code of the plastic-coated composite steel pipe, the code of the inner coating material and the nominal size. The water-supply lining plastic composite steel pipe is on the inner wall of the steel pipe, and is lined with plastic ethylene (PE), heat-resistant polyethylene (PE-RT), cross-linked polyethylene (PE-X), and polypropylene (PP-R) according to the requirements of the conveying medium. , Hard polyvinyl chloride (PVC-U), chlorinated polyvinyl chloride (PVC-C) and other thermoplastic pipes.

Its process is basically as follows. First, the ordinary steel pipe is subjected to a series of pre-treatments including chamfering and deburring, end face leveling, sandblasting and rust removal, etc., and then preheating to bring the temperature to 220 ℃, and then the preheated steel pipe is electrostatically charged. Spraying or dipping in polyethylene powder, if the product is sprayed with epoxy resin, it needs to be sent to the curing oven for curing. The curing temperature should reach about 280℃. The product can be taken out after four hours, and finally after repair, the product is processed.