Characteristics of steel plastic composite pipe: 1, Fittings with excellent sealing performance, anti-pull off, easy to install 2, Smooth wall. Pipe wall roughness is 0.007mm, small fluid resistance, no scaling, small head loss, no water hammer noise, threading does not wear 3, Low coefficient of linear expansion. Pipe line expansion coefficient is 1.2 × 10-5 / ℃, it is 1/10 to 1/12 of pure plastic pipe. 4, High ring stiffness. Plastic composite pressure pipe ring stiffness depending on the diameter of 8 ~ 80kN/m2, much higher than the glass pipes and plastic pipes and ring stiffness pure hole mesh and wire wrapped plastic pipe. 5, Normal temperature, pressure range, can be used for 50 years