description
3PP steel pipes are corrosion-resistant pipes coated with three layers of polypropylene, including epoxy primer, adhesive copolymer, and polypropylene top layer. The system has excellent resistance to mechanical damage, chemical corrosion and high temperatures (up to 110°C). It is mainly used in harsh environments such as subsea pipelines, chemical transportation, and high-temperature industrial applications, extending pipeline life to 30-50 years while reducing maintenance costs. The coating is applied by automatic electrostatic spraying, and each layer is subject to strict quality control.
Product Name: 3PP Coated Pipe, 3-Layer PP Steel Pipe, Polypropylene Anti-Corrosion Pipe.
Specifications:
- Outer Diameter: 60mm-3000mm
- Wall Thickness: 5-40mm
- Length: 6m / 6m / 12m / 12.5m (customizable)
Standard and Steel Grade:
| API SPEC 5L | Gr.B, X42, X52, X60, X65, X70 (PSL1/PSL2) |
| EN 10217-1 | P235GH, P265GH, P355NH |
| ASTM A106/A53 | Grade B |
| GB/T 9711 | L245, L290, L360, L415 |
Ends: Bevelled ends / Cap-protected / Flange-ready
Surface Treatment: Sandblasted to Sa 2.5 (ISO 8501-1),Coating: 3PP (Fusion-Bonded Epoxy + Adhesive + PP Overwrap)
Specification
| Category | Parameter | FBE Steel Pipe | 3PE Steel Pipe | 3PP Steel Pipe |
| Basic Specs | OD (mm/in) | 60-3000 (2″-118″) |
60-3000 (2″-118″) |
60-3000 (2″-118″) |
| Wall Thickness (mm) | 5.0-40 | 6.0-45 | 6.0-45 | |
| Length (m/ft) | 6-18 (20′-60′) |
6-18 (20′-60′) |
6-18 (20′-60′) |
|
| Coating Color | Green/Beige/Custom | Black (Std) | Yellow/Custom | |
| Temp. Range (°C) | -40~100 (150°C DL*) |
-40~80 | -40~140 | |
| Coating Structure | Base Layer | FBE Primer | FBE Primer | FBE Primer |
| Intermediate Layer | N/A | Copolymer Adhesive | Copolymer Adhesive | |
| Top Layer | N/A | Polyethylene (2-4mm) | Polypropylene (2-4mm) | |
| Certifications | Intl. Standards | ISO 21809-2 CSA Z245.20 |
ISO 21809-1 DIN 30670 |
ISO 21809-3 GB/T 23257 |
| Special Certs | NSF/61 (Potable Water) | – | – | |
| Performance | Cathodic Compatibility | Excellent | Good | Excellent |
| Abrasion Resistance | Moderate | Good | Superior | |
| Chemical Resistance | Good | Moderate | Superior | |
| Packaging | End Protectors | Beveled/Plain End Caps | Same as FBE | Same as FBE |
| Interlayer Padding | Specialty Spacers | Reinforced Spacers | Reinforced Spacers | |
| Max. Stack Height | 3.5m | 3.0m | 3.0m | |
| Commercial Terms | Delivery Time | 30-60 days | 45-75 days | 45-75 days |
| Payment Terms | 30% Deposit 70% Pre-ship |
Same as FBE | Same as FBE | |
| 20’GP Container Loading | 28 MT | 25 MT | 25 MT |
production process
3LPP Steel Pipe Manufacturing
Detailed 3LPP Coating Steel Pipe Manufacturing Process
1.Surface Pre-heating & Decontamination: Substrate steel pipes (LSAW, SSAW, or ERW) are pre-heated using high-capacity induction heaters to eliminate surface moisture, rust, and organic residues prior to grit blasting.
2.High-Speed Shot Blasting: The steel pipe surface is cleaned via centrifugal shot blasting to achieve Sa 2.5 cleanliness, creating a uniform anchor profile (50–90 µm) for optimal epoxy chemical bonding.
3.MF Induction Heating (High Temp): The cleaned pipe passes through medium-frequency (MF) induction coils to reach elevated application temperatures required for polypropylene processing (typically 200°C–240°C).
4.FBE Primer Spraying: Thermosetting Fusion-Bonded Epoxy (FBE) powder is electrostatically applied to form the high-adhesion corrosion barrier primer (≥80 µm).
5.PP Copolymer Adhesive Application: Before the FBE layer fully cures, a dedicated polypropylene copolymer adhesive layer (170–250 µm) is extruded directly over the epoxy to create an unbreakable inter-layer bond.
6.Polypropylene (PP) Topcoat Extrusion: High-density polypropylene (PP) topcoat (1.5–3.7 mm) is continuously wrapped or cross-head extruded around the pipe to form a extremely tough, heat-resistant outer shield.
7.Water Quenching & Cooling: The three-layer PP coated pipe enters a continuous water cooling bath to rapidly solidify the polypropylene shell and lock the coating geometry.
8.Spark Testing, End Cutback & Marking: 100% of the pipe surface passes through inline high-voltage spark testing (typically 25 kV) to verify zero defects. Pipe ends are cut back by 150mm with beveled edges, followed by stencil marking and end cap installation.
application
- 3PP coated steel pipes are widely used in transportation and structural engineering in harsh environments:
- Oil and gas transportation: submarine crude oil/natural gas trunk lines, city gas pipeline network
- Chemical industry: acid and alkaline medium transportation pipelines, chemical plant reaction area pipelines
- Energy engineering: steam pipelines for thermal power plants, casing for geothermal wells, carbon capture systems
- Water conservancy projects: seawater desalination pipes, municipal water supply and drainage trunk pipes, hydropower station pressure pipelines
- Mining and metallurgy: slurry transportation pipelines, high-temperature flue gas pipes in smelters, tailings backfill pipes
- Infrastructure engineering: anti-corrosion support pipes for cross-sea bridges, pile pipes for port wharves, and tunnel support structures
- Environmental protection projects: flue gas treatment pipes for garbage incineration plants, aeration pipes for sewage treatment plants
- Special use: steam pipes for food industry, clean media conveying pipes for pharmaceutical factories
advantages
Triple-layer protection, withstanding harsh environments
A three-layer composite structure builds a robust defense against seawater corrosion, fluctuating soil pH values, and chemical penetration, designed specifically for severe corrosion conditions.
Superior impact resistance, durable and long-lasting
The polypropylene outer layer provides excellent impact resistance, effectively reducing the risk of surface damage caused by rock excavation or mechanical construction.
Stable performance under high temperatures
Suitable for high-temperature working conditions, it is an ideal choice for the transportation of thermal fluids and geothermal applications, ensuring the performance stability of the coating in thermal environments.
Environmentally safe and certified
Meets international drinking water safety standards, uses environmentally friendly materials, and is suitable for ecologically sensitive areas.
Cost optimization throughout the entire lifecycle
Reduces long-term maintenance needs and significantly enhances the economic benefits of the project throughout its entire lifecycle.
packing
When transporting large-diameter 3PP corrosion-resistant steel pipes, the main focus is on effectively preventing pipe deformation and ensuring coating integrity. For this, it is necessary to use dedicated transport brackets for reliable fixation and strengthen protection at both ends of the pipe. The main transportation methods are as follows:
Container transportation: Suitable for short pipe sections, featuring cost-effectiveness and operational convenience.
Bulk carrier transportation: Suitable for large-volume transportation, requiring the development of strict pipe fixation plans.
Specialized pipeline transport vessels: Equipped with custom support systems, providing the highest level of transportation safety for long-distance maritime transport.
Protective measures during transportation:
Apply a protective film to the outer surface of the pipeline to prevent scratches and damage.
Install special protective covers at both ends of the pipeline.
When stacking multiple layers, cushioning pads must be placed between each layer.
FAQ
Q1: What is the main difference between 3LPP and 3LPE coated steel pipes?
While both utilize a three-layer anti-corrosion structure, 3LPP uses Polypropylene (PP) for its outer layer instead of Polyethylene (PE). 3LPP offers significantly higher operating temperature resistance (up to +110°C to +140°C vs. +70°C for 3LPE) and far superior mechanical hardness, making 3LPP superior for rocky soils, directional drilling, and deepwater subsea pipelines.
Q2: What is the maximum continuous operating temperature for 3LPP steel pipes?
Standard 3LPP coated steel pipes are rated for continuous service temperatures ranging from -20°C up to +110°C (+230°F), with specialized high-temperature polypropylene formulations capable of withstanding peak operating temperatures up to +140°C (+284°F).
Q3: Which international standards do your 3LPP coated pipes comply with?
Our 3LPP coated pipes strictly comply with major international pipeline coating specifications, including ISO 21809-3, DIN 30678, CAN/CSA Z245.21, and NACE RP0185. Substrate steel pipes are supplied to API 5L (PSL1/PSL2), ASTM A53/A106, and EN 10219.
Q4: Why is 3LPP preferred for subsea pipelines and horizontal directional drilling (HDD)?
Polypropylene has an extremely high indentation resistance and impact strength. During subsea pipe-laying or trenchless HDD pulling through abrasive rock formations, 3LPP effectively prevents gouges, cuts, and mechanical penetration that would otherwise breach standard PE coatings.
