my country's plastic pipes are developing rapidly, and the quality is constantly improving. Among them, polyethylene PE water supply pipes are widely used in building water supply, building drainage, buried drainage pipes, building heating, gas transmission pipes, electrical and telecommunication protection casings, industrial pipes, agricultural pipes, etc. due to their unique advantages. It is mainly used in the fields of urban water supply, urban gas supply and farmland irrigation. PE (polyethylene) material is widely used in the field of water supply pipe manufacturing due to its high strength, corrosion resistance and non-toxicity; because it does not rust Therefore, it is an ideal pipe material to replace ordinary iron water supply pipes.
Polyethylene (PE) pipes have become the second largest variety of plastic pipes in the world after PVC-U pipes, and are widely used in gas transmission, water supply, sewage, agricultural irrigation, oil fields, mining, chemicals, post and telecommunications and other fields. The application of polyethylene (PE) pipes began in the 1940s. The first generation of polyethylene pipe grade resins had low comonomer content, such as PE32, PE40, and PE63 grade resins. The extruded polyethylene pipes were subjected to long-term hydrostatic pressure. Brittle failure occurs during strength test; the second generation resin is PE80 grade, which provides comonomer content on the basis of the first generation resin, which greatly improves the environmental stress resistance (ESCR) performance of polyethylene pipe grade resin ; The third-generation resin is PE100 grade, PE100 resin has higher density and stiffness, 20 ℃, 50 years of creep resistance, while maintaining good ESCR performance. At present, medium or high-density polyethylene pipes of PE80 and PE100 grades should be used for gas transmission; PE80 and PE100 grades of medium- or high-density polyethylene pipes are usually used for PE water supply pipes, and PE63 has gradually been eliminated; PE32, PE40 low-density polyethylene pipes Ethylene is often used for irrigation.
Polyethylene (PE) pipes are usually classified according to the characteristics of polyethylene materials
1. According to the density of resin: According to the density of polyethylene resin, polyethylene pipes are divided into low density polyethylene (LDPE) pipes; medium density polyethylene (MDPE) pipes; high density polyethylene (HDPE) pipes.
2. According to the long-term hydrostatic strength grade of the material: The ISO standard organization divides the pipe and raw materials into five grades: PE32, PE40, PE63, PE80 and PE100 according to the lower confidence limit of the long-term hydrostatic strength predicted by polyethylene pipes. The physical and mechanical concepts of the category grades are the water temperature 20℃, the service life, and the corresponding static pressure strength (Mpa) of 97.5% probability prediction, which is converted to the minimum required strength (MRS) multiplied by 10. The material classification number, such as PE80, its minimum requirement The strength is 8.0Mpa.
3. According to the use of the pipeline: According to the use of the pipeline, it can be divided into polyethylene pipes for water supply and polyethylene pipes for gas.
