Three-layer polyethylene (3PE) coating is the mainstream external protection system for underground steel pipelines. It employs a three‑layer composite structure consisting of epoxy powder, an adhesive, and polyethylene, offering excellent chemical resistance and impact resistance, with a design service life of 30 to 50 years.
Our factory offers two corrosion‑protection grades—standard and enhanced—fully compliant with domestic and international standards such as GB/T 23257, SY/T 0413, and DIN 30670. These products are suitable for long‑distance oil and gas pipelines, urban gas distribution networks, and underground chemical‑process piping systems operating in various corrosive soil conditions.
The construction process comprises two methods: factory‑prefabricated jacketing and on‑site manual wrapping, with heat‑shrinkable joint‑repair fittings provided for corrosion protection and repair of welds. The protective coating effectively resists soil compaction and corrosive soil media, significantly reducing long‑term operation and maintenance costs.
Product Overview
The 3PE three-layer polyethylene anti-corrosion system is a multilayer composite protective structure whose overall performance far surpasses that of conventional single-layer anti-corrosion materials. Each of the three layers performs its specific function and works in concert to form a complete, tightly sealed protective barrier.
The fusion‑bonded epoxy powder at the base layer, upon high‑temperature melting, forms stable chemical bonds with the steel pipe surface, delivering exceptionally strong adhesion. It effectively isolates water, oxygen, and corrosive ions, thereby preventing electrochemical corrosion at its source and addressing the widespread issue of cathodic disbondment in the industry. The intermediate adhesive layer ensures tight bonding between the inner and outer layers, preventing delamination and coating failure. Meanwhile, the outer high‑density polyethylene layer provides robust physical protection, resisting impacts during installation, soil settlement, and surface abrasion. This comprehensive anti‑corrosion system can reliably serve for 30 to 50 years.
Implementation Standards and Construction Specifications
Applicable Standards
National Standard GB/T 23257-2017, Petroleum Industry Standard SY/T 0413-2002, and European Standard DIN 30670, meeting the procurement requirements of projects worldwide.
Surface Pre-treatment
Forming process
Weld joint repair
Precautions for Use
Corrosion-Resistant Coating Thickness Grades and Applicable Service Conditions
Standard grade
Total thickness: 2.0–2.2 mm; suitable for conventional underground municipal pipelines in soils with low corrosivity and subjected to light external loads.
Enhanced level
With a total thickness of 2.7 to 3.7 mm, it is specifically designed for highly corrosive environments such as saline‑alkali soils, coastal tidal flats, and chemical industrial sites, as well as for high‑pressure long‑distance pipelines that require long‑term stable operation.
Reinforced‑grade layered reference thickness: epoxy primer 50–127 μm, intermediate adhesive layer 170–250 μm, polyethylene outer layer 2.7–3.0 mm.
Core Product Advantages
Comprehensive corrosion protection
A multilayer barrier structure isolates corrosive media while simultaneously resisting chemical corrosion, microbial corrosion, and electrochemical corrosion.
Ultra-long service life
It offers stable performance for 30 to 50 years, reducing costs associated with pipeline maintenance and replacement, and delivering exceptional life-cycle cost-effectiveness.
Strong mechanical durability
The outer polyethylene layer cushions external impacts, reducing the risk of coating damage caused by construction activities and ground settlement.
Flexible construction adaptation
For large‑volume orders, factory‑based prefabrication and coating are available; on‑site manual wrapping is suitable for large‑diameter pipes, custom‑shaped fittings, and the renovation of aging pipelines.
Scope of Application
Although the initial processing costs of 3PE coating are higher than those of simple single-layer anti-corrosion products, its exceptionally low failure rate makes it the most reliable and cost-effective solution for long-term corrosion protection of underground pipelines. It is widely used in long-distance oil and gas pipelines, urban gas distribution networks, chemical‑medium transport lines, coastal underground pipelines, and high‑pressure energy transmission projects.
If you require a customized coating thickness or a tailored weld‑joint repair solution, please provide operating parameters such as pipe diameter, soil conditions, and the conveyed medium. Our company will calculate and select appropriate technical specifications in accordance with the relevant industry standards.
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Three-layer polyethylene anti-corrosion coating
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Hengtong Pipe Fittings Group
Hebei Hengtong Pipe Fitting Group manufactures steel fittings with integrated R&D, production, sales and services. With independent IP rights, we focus on two core product lines: concrete pump components and premium industrial pipe fittings.
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Phone:+86-13283241111
Email: rae@htpipefittings.com
howard@htpipefittings.com
Address: Zhenggang Industrial Park, Yanshan County, Cangzhou City, Hebei Province, China
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