3LPE Coated Carbon Steel Pipe
Manufacturing Process: Steel pipe pre-treatment, blast cleaning, epoxy powder coating, adhesive extrusion & PE outer layer extrusion
Standards: Manufactured in accordance with Chinese GB/T23257 & SY/T0413. Production technical requirements equivalent to ISO 21809 & DIN 30670
Surface: 3LPE coated exterior; pipe ends with bare steel cutback for field welding
Applications: Long-distance oil & gas transmission, water supply pipelines, municipal buried pipelines, onshore crossing projects
Value-added Services: Cut-to-length, pipe end beveling, coating repair, permanent marking
Export Packaging: Bundled with steel strips; waterproof wrapping & end caps on request
Supply: Direct factory supply for pipeline contractors, oil, gas & municipal engineering projects
3LPE Coated Carbon Steel Pipe for Buried and Subsea Pipelines
3LPE Coated Carbon Steel pipe is a pipe system with three coating layers that keep corrosion out. Buried lines use it, and so do trenchless jobs and subsea projects. A carbon steel core sits at the bottom of the build-up. Next comes a Fusion Bonded Epoxy primer. A copolymer adhesive makes up the middle layer, and the top layer is high-density polyethylene. Outer diameters span 89 mm to 2020 mm. Wall thicknesses run from 4.0 mm to 20 mm. Manufacturing follows GB/T 23257, SY/T 0413, ISO 21809-1, and DIN 30670.
How the Three-Layer System Works
Buried pipelines face three main corrosion threats from outside. The 3LPE coating answers all three. Electrochemical attack at the steel surface is one. Another comes from moisture that works its way through the coating. Installation and backfilling can cause mechanical damage, and that is the third.
Each layer performs a distinct function:
- FBE primer: forms a chemical bond with the blasted steel surface and resists cathodic disbondment
- Copolymer adhesive: keeps peel strength above 150 N/cm, holding the FBE and polyethylene layers together
- HDPE outer layer: this layer soaks up impacts and gives a slick surface, which suits trenchless installation methods
In testing, the cathodic disbondment radius stays under 7 mm at 65 °C. Electrical resistivity comes in above 10⁸ Ω·m². Service temperature runs from −40 °C to 80 °C without a break.
Product Specifications
| Parameter | Details |
|---|---|
| Base Pipe Grade | Q235B, Q355B, L245, L290, L360 |
| Outer Diameter | 89 mm – 2020 mm |
| Wall Thickness | 4.0 mm – 20 mm |
| Pipe Length | Random or fixed length; custom cutting available |
| Pipe End | Plain end or bevel end |
| Coating System | Three-layer polyethylene (FBE + Adhesive + HDPE) |
| Manufacturing Standard | GB/T 23257, SY/T 0413 |
| Equivalent Standards | ISO 21809-1, DIN 30670 |
| Operating Temperature | −40 °C to 80 °C |
| Adhesion (Peel) Strength | > 150 N/cm |
| Electrical Resistivity | > 10⁸ Ω·m² |
| Cathodic Disbondment | < 7 mm radius at 65 °C |
| Impact Resistance | Up to 10 J/mm of wall thickness |
| Mill Test Certificate | EN 10204 3.1, issued per heat |
Quality Control
Every pipe gets a spark holiday test and a coating thickness check before it leaves. The inspection rules come from GB/T 23257, which lines up with ISO 21809-1 and DIN 30670.
The following tests are applied at each production stage:
- High-Voltage Spark Test: 25 kV to confirm zero coating porosity across the full pipe length
- Peel Strength Test: V-cut method to verify the bond at both the PE/adhesive and adhesive/FBE interfaces
- DSC Cure Test: We use Differential Scanning Calorimetry to check that the FBE primer has fully cross-linked
- Indentation Resistance Test: verifies PE layer resistance to localized pressure from backfill or bedding materials
- Impact Resistance Test: falling weight method to confirm no cracks reach the steel surface
Heat traceability stays in place through every stage of production. Each shipment ships with an EN 10204 3.1 Mill Test Certificate. That document records raw material compliance and the performance of the finished pipe to GB standards. Need third-party inspection? We can arrange it on request.
Application Areas
Long-distance oil and gas transmission pipelines cross acidic marshland, abrasive rocky soil, and areas with stray electrical currents — conditions where a single FBE layer provides insufficient mechanical and chemical protection.
Municipal water supply and buried distribution trunk lines exposed to aggressive groundwater or stray currents benefit from the polyethylene outer layer as an additional barrier against external attack.
Trenchless crossing installations — including horizontal directional drilling under roads, railways, and river crossings — rely on the HDPE layer's toughness and low coefficient of friction to reduce pulling force and protect the coating during installation.
Offshore riser and tie-back systems use the 3LPE Coated Carbon Steel Pipe configuration where resistance to hydrostatic pressure and seawater ingress at the steel substrate is required.
Customization and Value-Added Processing
Pipes are available with cut-to-length machining, pipe end beveling, and factory-applied coating repair on cutback zones. Pipe ends are supplied with bare steel cutback for field welding unless otherwise specified.
Permanent marking is applied per project requirements. Export packaging uses steel strip bundling with waterproof wrapping; end caps are available on request.
Customization to project-specific dimensions, national standards, or client specifications can be discussed during the inquiry stage.
Supply and Documentation for 3LPE Coated Carbon Steel Pipe
Tianjin Youcheng Technology has been supplying steel products to international markets for 12 years, with distribution to projects in Kuwait, Russia, Ukraine, Greece, Brazil, Mexico, Kenya, and other markets. Approximately 200 tons of steel products are held in stock. Standard production lead time is 7–10 days. Inquiries receive a response within 24 hours.
Documentation provided with each order includes the EN 10204 3.1 Mill Test Certificate for the 3LPE Coated Carbon Steel Pipe per heat.
Packaging and Delivery
Global Clients Visit Our Steel Supplier Factory
FAQ
Q: What service life can be expected from this coating system?
A: The FBE primer forms a chemical bond with the steel, and the HDPE outer layer holds on top of it. Together they stand up to cathodic disbondment and mechanical damage, the two main reasons coatings fail early in buried pipelines. Look at design life claims against the soil conditions at your site and your cathodic protection design.
Q: Can this pipe carry hot fluids?
A: A standard 3LPE coating works for continuous service up to 80 °C. If process temperatures run higher than that, a three-layer polypropylene (3LPP) system is the right pick.
Q: How do crews fix coating damage out in the field?
A: Damage that small gets fixed in the field. Crews normally reach for dual-layer heat shrink sleeves, or they use melt-stick patches. Either one brings the barrier properties back at the spot that was hurt. No factory work is needed.
Q: How does 3LPE compare to single-layer FBE?
A: FBE bonds tightly to steel. Where it comes up short is mechanical protection, meaning impact and abrasion. A 3LPE system puts a copolymer adhesive over the FBE primer, then an HDPE outer layer on top. That gives better results in rocky soil, while the pipe is being moved, and in trenchless installation.
Q: Can the coating hold up against cathodic disbondment?
A: The FBE primer layer is built to stand up to cathodic disbondment. Say the outer PE layer gets damaged in one spot. At the steel interface, the FBE layer then acts as a second barrier.
Q: Which documents come with each shipment?
A: Every shipment comes with an EN 10204 3.1 Mill Test Certificate, issued per heat. It covers raw material compliance and how the finished pipe performs to GB standards. Third-party inspection can be arranged if you ask for it.
Contact Us
Email your inquiry to sales@youchengkjsteel.com. What 3LPE Coated Carbon Steel Pipe diameter do you need? Add the wall thickness and grade. Quantity matters too.
