PE pipes and fittings are mainly produced by chemical reaction of ethylene monomer, a-olefin monomer, catalyst system and different types of hydrocarbon diluents. The common processing method is slurry and gas-phase processing, but solution processing is also used in the production of very few manufacturers. The slurry reactor is usually a stirred tank or a relatively large annular reactor, which can be stirred circularly in the slurry. In the process of chemical reaction, as soon as ethylene contacts with comonomer and catalyst, it will react and produce polyethylene particles.

The reduction forming of high-pressure reducer is to put the tube blank with the same diameter as the large end of high-pressure reducer into the forming die, and then press along the axial direction of the tube blank to make the metal move and shrink along the die cavity. Due to the different sizes of reducer and reducer, its warping forming can also be divided into one-time pressing forming or multiple pressing forming.
Sometimes, expanding and reducing methods are combined according to the needs of material and product forming. In the process of reducing or expanding deformation pressing, cold pressing or hot pressing is determined according to different materials and reducing conditions. Generally, cold pressing shall be adopted as far as possible, but hot pressing shall be adopted for the manufacture of high-pressure reducer in case of severe work hardening caused by multiple diameter changes, wall thickness deviation or alloy steel materials.

PE water supply pipes are produced in strict accordance with national health standards. The raw materials are high-density polyethylene without any recycled materials and other additives.
1. Pressure
PE water supply pipe is used to transport tap water. Generally, it needs to pump water from underground to the ground and residents' homes. Because PE water supply pipes need to bear pumping pressure, water supply pipes are generally divided into five levels according to pressure, namely 0.6 MPa, 0.8 MPa, 1.0 MPa and 1.25 MPa. They bear 6 kg pressure, 8 kg pressure, 10 kg pressure, 12.5 kg pressure and 16 kg pressure. The higher the pumping pressure, the higher the pressure level of PE water supply pipe.
Polyethylene drainage pipes are generally used to discharge sewage and flow from top to bottom, so polyethylene drainage pipes generally do not need to consider the pressure grade.
2. Price
Since the PE water supply pipe is made of new HDPE, its cost will be higher than that of PE drainage pipe.
3. Materials
PE water supply pipe needs to deliver tap water for people's daily life, so PE water supply pipe must meet the national health standards, and PE water supply pipe must also use high-density polyethylene that meets the national standards.
Polyethylene drainage pipes shall be provided with recycled materials for customers' selection when they meet the applicable conditions and with the permission of customers.

How long is the PE pipe used? When we receive customer consultation, customers often ask such questions, and global plastic pipe supply experts will answer them here. The use time of PE pipe is determined by many factors, such as raw materials, production process, use method, environment, etc. First of all, raw materials, domestic PE raw materials basically can achieve anti-aging for 50 years, but because of different customer needs, so the use of national standard PE material to make PE pipes are not many, so sometimes the material is slightly deficient, then it has certain effect on aging. The second is the production process. Some manufacturers cut corners in production in order to seek high profits. For example, the difference of wall thickness exceeds the range, for example, the mechanical equipment is unstable, resulting in more impurities in the pipe, which affects the pressure bearing capacity of PE pipe itself.
Then, the damage or friction to the pipe itself in the construction of PE pipe will also have a certain impact. The damage to the pipe itself will reduce the service time of PE pipe.
Although PE pipe can resist corrosion, it will also have a great impact on the service time in case of particularly harsh environment, such as strong acid and alkali, high temperature (greater than 60 °), or long-term freezing. In the national standard, the service time of PE pipe is 50 years, which means that when the temperature is 23 °, the change of temperature will reduce the service time of PE pipe in a certain proportion.

PE pipe is a kind of polyethylene plastic, which is the basic plastic. Plastic bags and fresh-keeping films are PE, and HDPE is a thermoplastic resin with high crystallinity. The appearance of the original HDPE is milky white and translucent to a certain extent in the thin section. PE has excellent resistance to most domestic and industrial chemicals.
PE pipe butt weld, this method provides high reliability and diameter range and pressure process: heating the end of the pipe, using a tool called "mirror image" under the definition of contact pressure and temperature. The ends are quickly contacted and maintained under pressure during cooling.
PE pipe includes medium density polyethylene pipe and high density polyethylene pipe. It is divided into sdr11 and sdr17 according to wall thickness 6 series. The former is suitable for transporting gaseous artificial gas, natural gas and liquefied petroleum gas, while the latter is mainly used for transporting natural gas. Compared with steel pipe, the construction is simple and flexible. More importantly, it does not need anti-corrosion treatment, which will save a lot of processes. The disadvantage is that the equipment is not as good as steel pipe. Special attention shall be paid to the spacing of thermal heating during construction, and it shall not be exposed to the air and sunlight, which will cause damage to chemicals and prevent the leakage of sewage pipeline.
China's municipal pipe market, in which sewage pipe and gas pipe are its two major application markets. The Chinese name of PE chemistry is polyethylene. PE material is widely used in the field of water supply and drainage manufacturing because of its high strength, high temperature resistance, corrosion resistance and wear resistance. Because it will not rust, it is an ideal pipe to replace ordinary iron water supply pipe. Therefore, the Bureau of standards has made a lot of amendments in the new GB / t13663 standard, stipulating that different levels of PE80 and PE100 of water supply pipes correspond to different pressure strengths, and the tensile strength performance in the old standard is removed, while the elongation at break (greater than 350%) is increased, that is, the basic toughness is emphasized.

PE pipe is directly produced by extruder, while steel wire mesh skeleton pipe is produced by steel wire and PE material. There are more processes than PE pipe in the process. Since the two are used for the same purpose, why launch two products? In fact, this is due to a defect of PE pipe, that is, the rigidity is not enough. When it is suitable for super pressure and super long-distance water transmission, the pipe often bears a great impact. Under super pressure, the pipe body may break, thus affecting normal life. The steel mesh skeleton pipe just solves the weakness of PE pipe rigidity, So can PE pipes be abandoned with steel wire mesh skeleton pipes? In fact, it is not. Because the steel wire mesh skeleton pipes adopt electrothermal fusion joints, the pipe body and joints will crack due to rigidity in the actual use process. At the same time, due to the strong rigidity of the pipe body, the stretching of the pipe body will be affected and the pipe body will be broken, At the same time, the material development data show that the pipe is suitable for hard soil, but not for soft soil with many water sources. In fact, to put it bluntly, the steel mesh skeleton pipe only makes up for the rigid shortcomings of PE pipe, but in the actual use process, PE pipe can still be competent for various types of projects, municipal, urban and rural water. After all, the toughness, compression resistance, tensile resistance, corrosion resistance, earthquake resistance and installation convenience of PE pipe have been recognized by the society.

At present, the plastic pipe or steel plastic composite pipe is usually welded by heating the plastic to the molten state. The specific welding methods are usually the following two: 1. Hot melting and plug-in: first heat the side wall of the socket of the plastic pipe or steel plastic composite pipe and pipe fitting to the molten state, and then insert the plastic pipe or steel plastic composite pipe into the socket of the pipe fitting to realize the welding; 2. Electric fusion after insertion: electric fuse is embedded in the inner wall of the socket of pipe fittings in advance. After the pipe is inserted into the socket of pipe fittings, the electric fuse is energized to heat the electric fuse and melt the plastic, and finally realize fusion.
The utility model relates to a welding method, which is mostly suitable for the welding of small-diameter pipes because the plastic is in a molten state during insertion, which is prone to deviation and melting tumor;
The two welding methods need to prepare electric fuse in advance in the side wall of pipe fitting socket, so the side wall of pipe fitting socket is required to have a certain thickness to lay electric fuse, so it is suitable for the connection of large-diameter pipeline rather than small-diameter pipeline.
Therefore, the above two methods are difficult to weld the full specification steel plastic composite pipe, and the leakage after welding cannot be remedied.

At present, plastic pipes or steel plastic composite pipes are generally welded by heating the plastic to the molten state. There are usually the following two welding methods:
1. Plug in after hot melting: first heat the side wall of the socket of plastic pipe or steel plastic composite pipe and pipe fitting to the molten state, and then insert the plastic pipe or steel plastic composite pipe into the socket of pipe fitting to realize fusion;
2. Electric fusion after insertion: electric fuse is embedded in the inner wall of the socket of pipe fittings in advance. After the pipe is inserted into the socket of pipe fittings, the electric fuse is energized to heat the electric fuse and melt the plastic, and finally realize fusion.
The utility model relates to a welding method, which is mostly suitable for the welding of small-diameter pipes because the plastic is in a molten state during insertion, which is prone to deviation and melting tumor;
The two welding methods need to prepare electric fuse in advance in the side wall of pipe fitting socket, so the side wall of pipe fitting socket is required to have a certain thickness to lay electric fuse, so it is suitable for the connection of large-diameter pipeline rather than small-diameter pipeline. Therefore, the above two methods are difficult to weld the full specification steel plastic composite pipe, and the leakage after welding cannot be remedied.

Compared with other types of steel plastic pipes (such as PESI pipe and SP pipe), the main pressure bearing layer of steel plastic composite pressure pipe is borne by the welded steel pipe in the negative pressure pipe, and its plastic layer is the auxiliary pressure bearing layer, which also plays the role of anti-corrosion protection. Therefore, the pressure bearing capacity of the pipe is basically not affected by temperature change and aging of plastic layer, and the problem of delamination of steel plastic composite interface is solved at the same time; Steel plastic composite pressure pipe not only inherits the advantages of gold pipe and plastic pipe, but also overcomes their respective disadvantages. It is a new type of pipe integrating the advantages of metal pipe and plastic pipe It has the following characteristics:

PSP steel plastic composite pressure pipe is formed by rolling steel strip and continuous argon arc butt welding. It adopts the composite structure of extruded inner and outer composite plastic layer and reinforced welded steel pipe in the middle. The utility model not only overcomes the problems of easy corrosion, easy scaling and unsanitary of the steel pipe, but also solves the defects of low strength, easy deformation and short service life of the plastic pipe. Combining the advantages of steel pipe and plastic pipe, it has the advantages of high strength, good rigidity, good oxygen isolation, corrosion resistance, scaling resistance, good sanitary performance, easy buried detection and so on. Because of its excellent performance, it is widely used in water supply, drainage, sewage and other projects of building cold and hot water, fire protection, chemical industry, petroleum, machinery, pharmacy, food and HVAC. Because of its good anti signal interference, it can also be used in optical cable threading pipelines such as expressway, high-speed railway, subway and 5g Zhejiang Lianjing company has mastered the core precision forming welding technology of thin-wall metal welding and steel-plastic composite technology. Through the research on the roughness of steel-plastic composite pressure pipe of Zhejiang University, according to the structural characteristics of multiple reinforced steel-plastic composite pressure pipe, it simulates the water flow condition, so as to lay a solid foundation for the practical application of pipes. PSP steel plastic composite pressure pipe is connected with electromagnetic double hot-melt pipe fittings, which makes the pipe construction more convenient and efficient, better anti-corrosion performance, higher pressure and longer service life.