Plastic Coated Steel Pipe

I Plastic coated composite steel pipe introduction:

Plastic-coated composite steel pipe (also known as fusion bonded epoxy coating steel pipe) is a composite pipe with a steel pipe as the base, and a plastic anti-corrosion layer (such as polyethylene PE, epoxy resin EP) is melt-coated on the inner and outer surfaces through spraying, rolling, dipping, suction and other processes. It has both metal strength and plastic corrosion resistance and is widely used in water supply and drainage, fire protection, chemical industry, electric power and other fields.

II Epoxy coated steel pipe related parameters

III. Advantages of plastic coated composite steel pipe

Coated carbon steel pipes, especially single-layer anti-corrosion epoxy powder pipes, excel in harsh environments (such as direct burial, humid) and critical applications (such as cable sheathing):

i. Strong environmental adaptability: Designed for direct burial, continuous humid environments, and can withstand large temperature changes (high and low temperatures).

ii. Excellent anti-interference: When used as a cable sheath, it can effectively shield external electromagnetic interference (EMI) and ensure signal transmission.

iii. High pressure bearing capacity: The structure is sturdy and can withstand pressures up to 6 MPa (about 870 psi).

iv. Reliable electrical insulation: The epoxy coating provides excellent electrical insulation performance, effectively preventing leakage of wires in the pipe.

v. Convenient construction: The inner wall is smooth and burr-free, which greatly facilitates the threading (pulling) of wires or cables.

IV. Plastic coated composite steel pipe national standard comparison table

Key additional notes

i. Chinese standard subdivision application:

Civil water supply: CJ/T 120 + GB/T 17219 health certification;

Fire protection system: GB/T 5135.20 (red logo + fire resistance);

Oil and gas transportation: SY/T 0442 (high pressure resistance) or ISO 21809 (UV resistance);

Coal mine scene: MT 558.6 (flame retardant and antistatic).

ii. Coating selection basis:

Chemical corrosion resistance: epoxy resin (EP) is preferred;

Buried/low cost: polyethylene (PE) is more economical;

High temperature environment: fire protection pipelines must use EP (resistant to more than 100℃).

iii. Common requirements for detection:

Pinhole test: The voltage is set according to the coating thickness (≤0.4mm uses 1500V, >0.4mm uses 2000V);

Adhesion: China uses the cross-cutting method (1-3 levels are qualified), and the United States uses the peeling method (≥15N/mm).

V. Application areas of plastic coated composite steel pipe:

i. Municipal livelihood field

a. Urban water supply: replace galvanized pipes, used for hot and cold water pipes in residential areas, with smooth inner wall and no scaling, in line with GB/T 17219 sanitary standards, to ensure drinking water safety.

b. Sewage transportation: used for municipal sewage and industrial wastewater pipes, resistant to acid and alkali corrosion, such as sewage treatment plant discharge pipes.

c. Fire protection system: used for fire sprinkler pipes and fire hydrant pipes, resistant to high pressure (≥2.5MPa), excellent fire resistance (resistant to high temperature of 100℃), and certified by GB/T 5135.20.

d. HVAC circulating water: used for building heating/cooling circulating water pipes, applicable temperature range of -30℃~100℃, resistant to thermal expansion and contraction deformation.

ii. Industrial field

a. Chemical fluid transportation: used for conveying acid, alkali, and salt solutions (such as hydrochloric acid and dilute sulfuric acid), resistant to non-oxidizing corrosion, suitable for process pipes and discharge pipes in chemical plants.

b. Mines: used for ventilation pipes, slurry/tailings discharge pipes, wear-resistant and impact-resistant, pipes used underground in coal mines must comply with MT 558.6 flame retardant certification.

c. Oil fields: used for oily sewage and oil-gas mixed transmission pipes, adapted to SY/T 0442 high pressure resistance (≥6MPa) standard.

d. Power engineering: used for power plant chemical water treatment and waste slag transmission pipes, high temperature resistance and excellent insulation.

iii. Power and communication protection

a. Cable threading sleeve: used for underground cable protection pipes (such as municipal power wells and tunnel projects), coating insulation to prevent electrical corrosion, soil stress and plant root damage.

b. Communication pipelines: used for optical fiber and communication line sheath pipes, specifications cover DN15-DN1200, and flexible connection methods (groove/flange).

iv. Emerging and special scenarios

a. Shipping and marine engineering: used for ship ballast water pipes and dock water supply pipes, resistant to seawater corrosion, with a service life of 50 years.

b. Gas transportation: modified coatings are suitable for natural gas transportation and have strong anti-permeability.

c. Agricultural irrigation: used for deep well water pipes and sprinkler systems, wear-resistant and lower cost than stainless steel pipes.