Plastic-coated composite steel pipes are also called plastic-coated steel pipes. Plastic-coated steel pipes are based on steel pipes and use plastic powder as the coating material. The inner surface is melt-coated with a plastic layer, and the outer surface is coated with a plastic layer. Or steel-plastic composite products with anti-corrosion layer of other materials. Plastic-coated steel pipes not only have the advantages of high strength, easy connection, and resistance to water impact, but also overcome the corrosion of steel pipes when exposed to water. , Pollution, scaling, low strength of plastic pipes, poor fire-fighting performance and other shortcomings, the design life can be up to 50 years.