Plastic-coated composite steel pipe is a new type of pipeline material recently developed in China. It adopts a plastic-coated protective layer inside and outside, and the middle is a composite structure of reinforced welded steel pipe or seamless pressure-bearing steel pipe, which overcomes the easy rust and corrosion of the steel pipe itself. , high pollution, and the defects of low strength and easy deformation of plastic pipes, which integrate the common advantages of steel pipes and plastic products, and are environmentally friendly products promoted by the country. The plastic-coated composite steel pipe is a layer of polyethylene (PE) resin, ethylene-acrylic acid copolymer (EAA), epoxy (EP) powder, and non-toxic polypropylene (PP), or The steel-plastic composite pipe is composed of 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, but also overcomes the corrosion, pollution, scaling and The plastic pipe has the disadvantages of low strength and poor fire performance, and the design life can reach 50 years. The main disadvantage is that when bending, thermal processing, and electric welding cutting are not allowed during installation, the cutting surface should be painted with the non-toxic room temperature curing glue provided by the manufacturer. The main specifications are Φ15-Φ300. To improve the corrosion resistance of steel pipes, general steel pipes are galvanized.
Galvanized steel pipe is divided into two types: hot-dip galvanized and electro-galvanized. The hot-dip galvanized layer is thick, the cost of electro-galvanized is low, and the surface is not very smooth. Oxygen blowing welded pipe: used as oxygen blowing pipe for steelmaking, generally small-diameter welded steel pipe, with eight specifications ranging from 3/8 to 2 inches. It is made of 08, 10, 15, 20, or 195-Q235 steel strips. To prevent corrosion, some need to be aluminized. Most of the old houses use galvanized pipes. Now the iron pipes used for gas and heating are also galvanized pipes. Galvanized pipes are used as water pipes. After a few years of use, a lot of rust is formed in the pipes, and the yellow water that flows out not only pollutes Sanitary ware, and mixed with bacteria that grow on the uneven inner wall, the rust causes the heavy metal content in the water to be too high, which seriously endangers the health of the human body. In the 1960s and 1970s, developed countries in the world began to develop new types of pipes and gradually banned galvanized pipes. Four ministries and commissions including the Ministry of Construction of China have also issued a document stating that galvanized pipes have been banned since 2000. At present, galvanized pipes are rarely used for cold water pipes in newly built communities, and galvanized pipes are used for hot water pipes in some communities.