(1) Good creep resistance and high mechanical strength
As plastic will creep under normal temperature and stress, and brittle fracture will occur under high stress, the allowable stress and bearing capacity of pure plastic pipes are very low (generally within 1.0MPa). The mechanical strength of steel is about 10 times that of thermoplastics. It is very stable within the temperature range of plastics and does not creep. The results show that the steel mesh skeleton can effectively restrain the creep of plastics and improve the fracture strength of plastics. Therefore, the allowable stress of steel wire skeleton polyethylene composite pipe is twice that of plastic pipe.
(2) Good temperature resistance
In the use temperature range, the strength of plastic pipes generally decreases with the increase of temperature. When the temperature rises by 10 ℃, the strength of plastic pipes decreases by more than 10%. As the steel mesh skeleton bears about 2/3 of the strength of the steel mesh skeleton polyethylene composite pipe, its strength decreases less with the increase of service temperature than any pure plastic pipe. The test results show that the strength of the steel mesh skeleton polyethylene composite pipe decreases by less than 5% every 10 ℃.
(3) Good rigidity, impact resistance, dimensional stability and moderate flexibility
The elastic modulus of steel is usually about 200 times that of HDPE. Due to the strengthening effect of the steel mesh framework, the rigidity, impact resistance and dimensional stability of the steel mesh polyethylene composite pipe are superior to any pure plastic pipe. At the same time, because the space truss itself is a flexible structure, the composite pipe also has certain flexibility in the axial direction. Therefore, the pipe has the characteristics of rigid flexible combination, and has excellent performance in loading and unloading, transportation, installation adaptability, operation reliability, etc. Underground devices can effectively bear the sudden impact load caused by settlement, sliding and vehicles. Small diameter pipes can be properly bent and arranged in relief or serpentine form to save pipe fittings.
(4) Small thermal expansion coefficient
Since the linear expansion coefficient of steel wire for plastic pipe is 10.6~12.2 × 10-6 (1/℃), while the linear expansion coefficient of pure plastic pipe is 170 × 10-6 (1/℃), so the thermal expansion coefficient of the composite pipe under the grid constraint is greatly improved, which is lower than that of the general plastic pipe. The test results show that the expansion coefficient of steel skeleton polyethylene composite pipe is 35.49 × 10-6 (1/℃), only 3-3.4 times of ordinary carbon steel pipe. The experimental results show that the thermal compensation device cannot be used for buried installation, and the winding pipe laying can play a role of absorption (or release), thus reducing the installation cost.
(5) No rapid cracking
Pure plastic pipes, especially large diameter pure plastic pipes, are prone to rapid cracking due to local defects and stress concentration (hundreds of meters to more than one kilometer in a flash) under the continuous circumferential stress at low temperature. Therefore, countries all over the world put forward higher requirements for the crack resistance of pipes. However, low carbon steel does not have brittle fracture problem. The existence of wire mesh makes the plastic deformation and stress not reach the critical point of rapid cracking. Therefore, theoretically, there is no problem of rapid cracking of the steel mesh skeleton polyethylene composite pipe.
(6) Steel plastic composite is even and reliable
Because the steel plastic interface is continuous and regular, the steel plastic composite pipe on the market is prone to delamination under long-term alternating stress, resulting in leakage at the joint, bottleneck shrinkage and blockage failure. In contrast, the steel wire skeleton polyethylene composite pipe is a network structure, which closely combines the plastic and the steel wire mesh through a special hot melt adhesive (modified HDPE). The bonding force of the two materials is large and uniform, and the stress concentration is small.
(7) Double sided anti-corrosion
The steel wire mesh frame is compounded by a special hot-melt adhesive layer. The internal and external surfaces of the pipeline have the same anti-corrosion performance, wear resistance, smooth internal wall, small transmission resistance, no scaling and wax deposition, obvious energy-saving effect, and more economical and convenient for underground transportation and corrosive environment.
(8) Good self tracking characteristics
Due to the existence of the steel wire mesh framework, the polyethylene composite pipe buried underground can be positioned by conventional magnetic testing methods, avoiding the damage of other excavation projects. This kind of damage is most serious for pure plastic pipes and other non-metallic pipes.
(9) Easy and flexible adjustment of product structure and performance
The structure and performance of the product can be adjusted to meet different pressure, temperature and corrosion resistance requirements by changing the steel wire diameter, wire spacing, plastic layer thickness, plasticity and type.
(10) Special electric welding joints, with various varieties, are fast and reliable in installation.
