Plastic-coated steel pipes, also known as plastic-coated steel pipes, steel-plastic composite pipes, or plastic-coated composite steel pipes, use steel pipes as the base material and PE (modified polyethylene) or EP (epoxy resin) as the main anti-corrosion material through hot-dip plastic coating. A layer of PE anti-corrosion coating is fused to the inner surface of the steel pipe through spraying, rolling, dipping, or suction processes, or an EP anti-corrosion layer is fused to both the inner and outer surfaces. Plastic-coated steel pipes have excellent corrosion resistance. The coating itself also has good electrical insulation properties, preventing electrolytic corrosion. They have low water absorption, high mechanical strength, and a low coefficient of friction, enabling long-term use. They also effectively prevent damage from plant roots and soil stress.

First, Advantages of Plastic-Coated Steel Pipes:
1. Adaptable to buried and humid environments, and resistant to high and extremely low temperatures.
2. Strong anti-interference ability; if used as a cable conduit, plastic-coated steel pipes can effectively shield external signal interference.
3. Good pressure resistance, with a pressure capacity up to 6 MPa.
4. Excellent insulation performance; as a protective conduit for electrical wires, it will never leak electricity.
5. Burr-free, smooth pipe wall, suitable for threading wires or cables during construction.

Second, Application Areas of Plastic-Coated Steel Pipes
1. Various types of circulating water systems (civilian and industrial circulating water), with excellent performance and a corrosion resistance lifespan of up to 50 years.
2. Fire-fighting water supply systems.
3. Water supply and drainage for various buildings (especially suitable for hot and cold water systems in hotels, restaurants, and high-end residential areas).
4. Transportation of various chemical fluids (this product is resistant to acid, alkali, and salt corrosion).
5. Buried conduits and road crossing pipes for electrical wires and cables.
6. Ventilation, water supply, and drainage pipes for mines and shafts.
7. Urban sewage pipelines.

3PE anti-corrosion steel pipe refers to a three-layer polyolefin coating (MAPEC) external anti-corrosion steel pipe. The base material includes seamless steel pipe, spiral steel pipe, and straight seam steel pipe. Its excellent corrosion resistance, water vapor penetration resistance, and mechanical properties have led to its widespread use in industrial steel pipelines. It is a commonly used type of anti-corrosion steel pipe in China. Other anti-corrosion methods include IPN8710, FBE epoxy powder, and epoxy coal tar pitch. Generally, it refers to the external anti-corrosion of the steel pipe. The anti-corrosion layer of 3PE anti-corrosion steel pipe is crucial to the lifespan of buried steel pipelines. Steel pipes of the same material can vary greatly; some can remain uncorroded underground for decades, while others leak within years, due to the different external anti-corrosion layers they employ.
Third, the structure of 3PE anti-corrosion steel pipes:
No.1 layer: Epoxy powder (FBE>100um)
No.2 layer: Adhesive (AD) 170~250um
No.3 layer: Polyethylene (PE) 2.5~3.7mm

Fourth, the advantages of 3PE anti-corrosion steel pipes.
Many people only know part of the uses of 3PE anti-corrosion steel pipes. Ordinary steel pipes will suffer severe corrosion in harsh environments, thus reducing their service life. 3PE anti-corrosion steel pipes have a relatively long service life, generally 30-50 years. Long-term operation can save considerable resources, significantly reduce energy costs, and has strong waterproof and corrosion resistance. They do not require additional pipe trenches and can be directly buried underground or underwater. Construction is simple and quick, and the overall cost is relatively low. They also have good corrosion resistance and impact resistance under low-temperature conditions, and can be directly buried in frozen soil in certain environments.

Fifth, Applications of 3PE Anti-corrosion Steel Pipes
The applications of 3PE anti-corrosion steel pipes are truly extensive. They are suitable for coal mine underground water supply and drainage, underground spraying, positive and negative pressure ventilation, gas extraction, fire sprinkler systems, and other pipeline networks. They are also used in thermal power plants for process water, waste residue, and return water transportation. They have excellent applicability for water supply pipelines in sprinkler and spray systems. They are used as cable protection sleeves in power, communication, and highway projects. They are suitable for steel pipelines for water supply in high-rise buildings, heating networks, tap water projects, gas transmission, and buried water transmission. They are also used in oil transportation pipelines, and process steel pipelines for transporting corrosive media in chemical, pharmaceutical, and printing and dyeing industries. They are used in sewage treatment discharge pipes, sewage pipes, and anti-corrosion projects for biological treatment ponds. They are also used in agricultural irrigation pipes, deep well pipes, drainage pipe networks, and many other applications. It can be said that 3PE anti-corrosion steel pipes are indispensable in current construction, and it is believed that with the advancement of technology, they will achieve even greater success in the future.

Finally, a simple way to distinguish between plastic-coated steel pipes and 3PE anti-corrosion steel pipes is that plastic-coated steel pipes have a very smooth surface, while 3PE steel pipes, because the outer layer of the steel pipe is wrapped with an anti-corrosion polyethylene tape, look like a series of joints.