3PE anti-corrosion steel pipe for long-lasting durability
High-performance 3PE anti-corrosion steel pipe
3PE anti-corrosion steel pipe suitable for harsh environments
Quality 3PE anti-corrosion steel pipe for pipeline use

3pe Anti-Corrosion Steel Pipe

Product Specifications

Product Name: 3PE Corrosion-Resistant Steel Pipes、Anti-corrosion Steel Pipe with 3pe Coating

OD: 219mm - 1420mm

WT: 4.5mm - 25.4mm

Length: 6m - 12m

Material: Q195、Q215、Q235、Q345、16Mn、20#、45#

Standard: GB/T 9711、SY/T 5037、GB/T 24186、API 5L、ISO 3183、DIN 30670、EN 10224 / EN 10208

Coating Type: FBE、Adhesive Layer、HDPE

Application: Oil, natural gas, urban water supply, chemical and industrial pipelines, especially suitable for underground long-distance pipelines and corrosive environments.

I. What is 3PE anti-corrosion steel pipe?

3PE anti-corrosion steel pipe refers to a steel pipe with three layers of polyethylene anti-corrosion layer coated on the surface of ordinary steel pipe (seamless, straight seam, spiral steel pipe), which is used to prevent the pipeline from rusting, corroding and being damaged when buried underground or in corrosive environments.

The characteristics of 3PE anti-corrosion steel pipe are as follows:

i. The base pipe for 3PE corrosion-resistant steel pipe is typically seamless carbon steel pipes or low-alloy steel, such as Q235, Q345, and 16Mn, due to their excellent mechanical properties and pressure-bearing capacity. For applications requiring higher pressures, seamless alloy steel pipe can also be used as the base pipe.

ii. To provide reliable corrosion protection, this pipe utilizes a robust three-layer construction:
（1）Base layer (epoxy powder coating (FBE)): First, FBE is applied to the steel pipe surface, providing the necessary corrosion protection.
（2）Intermediate layer (adhesive resin): Subsequently, the adhesive resin layer strengthens the adhesion between the base layer and the outer polyethylene layer, further strengthening the three-layer protective structure.
（3）Outer layer (high-density polyethylene (HDPE)): Finally, the HDPE layer forms the final barrier, effectively protecting against mechanical damage, moisture, and UV rays.

iii. Pipeline engineers widely use this three-layer coated pipe in oil, gas, municipal water supply, chemical, and industrial pipelines. In long-distance underground pipelines and highly corrosive environments, 3PE anti-corrosion steel pipes deliver excellent performance, maintaining the safety and durability of pipelines over a long period.

II. Steel pipe corrosion resistance grade

i. Epoxy Primer (FBE) Layer Thickness

Typical Thickness: ≥ 150 μm
Protective Function: Ensures a tight bond between the steel pipe surface and the polyethylene layer, while providing primary corrosion protection

ii. Adhesive Layer

Thickness: Typically 0.1–0.3 mm
Protective Function: Enhances adhesion between the base layer and the outer polyethylene layer, improving overall corrosion protection

iii. Outer Polyethylene (HDPE) Layer Thickness

Typical Thickness: 2.0–3.5 mm, adjustable based on environmental requirements
Protective Function: Resists mechanical damage, moisture, and UV rays; serves as the primary protective layer for 3PE corrosion protection

iv. Applicable Corrosion Protection Grade Reference

Anti-corrosion Grade Working-pipe Material Coating Structure Total Coating Thickness Applicable Environment Typical Applications
C1 (Light corrosion) Q235 FBE + Adhesive + HDPE 2.0 mm Above-ground pipelines, non-corrosive environments Water-plant transmission lines, urban water-supply branches
C2 (Medium corrosion) Q345 / 16Mn FBE + Adhesive + HDPE 2.5 mm Normal buried pipelines, moist soils Urban water-supply mains, HVAC piping
C3 (High corrosion) Q345 / 16Mn FBE + Adhesive + HDPE 3.0 mm Seawater, acidic/alkaline soils, hot-humid zones Long-distance oil & gas lines, chemical-plant piping
C4 (Extreme corrosion) Low-alloy high-strength steel FBE + Adhesive + HDPE ≥ 3.5 mm Highly aggressive chemical environments or long-life buried pipelines Petrochemical plants, offshore platforms, long-life oil pipelines

III. 3PE anti-corrosion pipe implementation standards

i. Steel Pipe Standards
Domestic Standards:
GB/T 9711 – Steel Pipe for Transportation
GB/T 3087 – Low and Medium Pressure Boiler Tubes
SY/T 5037 – Technical Specification for External Anticorrosion Coatings for Petroleum and Natural Gas Pipelines
International Standards:
API 5L – Steel Pipe for Petroleum and Natural Gas Transportation
ISO 3183 – Steel Pipe for Petroleum and Natural Gas Pipelines
DIN 30670 – German Standard for Anticorrosion Steel Pipes
EN 10224 / EN 10208 – European Steel Pipe and Anticorrosion Requirements

ii. Anticorrosion Coating Application and Testing Standards
FBE Epoxy Powder Primer: Comply with SY/T 0416 or ISO 21809-1
Tie Coat and Polyethylene Outer Layer: Comply with ISO 21809-2
Anticorrosion Performance Testing: Including adhesion, impact testing, heat resistance, and salt spray corrosion resistance.

IV. What are the types of 3PE anti-corrosion steel pipes?

The types of 3PE corrosion-resistant steel pipes can primarily be distinguished based on the production process of the base pipe they envelop.

(1) 3PE corrosion-resistant pipes based on welded steel pipes:
ERW steel pipes + 3PE corrosion protection:
This is a very common combination. ERW steel pipes (resistance welded straight seam pipes) are cost-effective and dimensionally precise. When combined with a 3PE corrosion-resistant coating, they are highly suitable for pipelines transporting media such as oil, natural gas, and water.
LSAW steel pipes (submerged arc welding steel pipes) + 3PE corrosion protection:
LSAW steel pipes typically have larger diameters, thicker walls, and stronger pressure-bearing capabilities. Combined with 3PE corrosion protection, they are primarily used for large-diameter, high-pressure long-distance oil and gas pipelines.
SSAW steel pipes (spiral submerged arc welded pipes) + 3PE corrosion protection:
Spiral welded pipes can also be coated with 3PE corrosion protection. They are commonly used in large-diameter transmission pipelines, especially when flexibility or specific diameter requirements are needed.

(2) 3PE corrosion-resistant pipes based on seamless steel pipes:
Seamless steel pipes + 3PE corrosion protection:
Seamless steel pipes have no weld seams, ensuring better overall uniformity and typically stronger pressure-bearing capacity. In scenarios with extremely high safety requirements, extremely high pressure, or relatively smaller diameters (such as high pressure boiler pipes or critical pipelines in certain chemical plants), seamless steel pipes are selected for 3PE corrosion protection.

V. What is the service life of 3PE corrosion-resistant steel pipes?

i. Basic service life range

Under standard construction and normal operating conditions, 3PE corrosion-resistant steel pipes generally provide a service life of 30 to 50 years, as verified by authoritative testing institutions in the petroleum and natural gas industry. Furthermore, major domestic projects, such as the West-to-East Gas Pipeline (nearly 4,000 kilometers) and the Shaanxi-Beijing Natural Gas Pipeline, have adopted 3PE corrosion protection with a design service life of 50 years, and they continue to operate smoothly to this day.

ii. Key Factors Affecting the Service Life of 3PE Corrosion-Resistant Steel Pipes

（1）Environmental Conditions
Corrosive environments, such as high-salt, high-humidity, or strongly acidic/alkaline soils, can accelerate coating aging and reduce service life. Moreover, if the transported medium contains corrosive components like hydrogen sulfide or high-salt wastewater, internal corrosion protection (e.g., IPN8710 coating) is necessary to prevent internal damage.

（2）Coating Quality
High-quality, enhanced-grade coatings ensure longer durability compared with standard-grade coatings. However, adhesion issues, uneven thickness, or bubbles during production can shorten the service life, so strict quality control is essential.

3PE Corrosion-Resistant Pipe Specifications
Type Corrosion Layer Thickness Application Scenario Expected Lifespan
Standard Grade 3PE 2.0–2.2 mm General soil environment, low-pressure water conveyance 30–40 years
Enhanced Grade 3PE 2.7–3.7 mm Highly corrosive soil, oil and gas mainlines Over 40–50 years

（3）Construction and Maintenance
Proper protection of welded joints and regular inspections, including leak detection and peel strength tests, can significantly extend pipe life. Neglecting maintenance, however, may create corrosion entry points that reduce overall durability.

（4）Temperature Adaptability
3PE pipes perform reliably between -40°C and 120°C. Nevertheless, prolonged exposure above 80°C may accelerate polyethylene layer aging, which can affect long-term performance.

iii. Recommendations for extending service life

(1) Selection and Matching
In highly corrosive or high-pressure environments (such as chemical pipelines and subsea gas transmission), prioritize the use of enhanced-grade 3PE and pair it with seamless steel pipe substrates.
When transporting drinking water, it is recommended to add an IPN8710 food-grade anti-corrosion layer to the inner wall.

(2) Construction Standards
The steel pipe surface must meet the Sa2.5 rust removal standard, and moisture and oil residue must be completely removed.
Joints should be sealed with radiation-crosslinked polyethylene heat-shrinkable tape to ensure equivalent sealing with the main corrosion-resistant layer.

(3) Maintenance Strategy
Corrosion-resistant layer conductivity testing and damage repair should be conducted every five years.
In areas with low soil resistivity, a cathodic protection system (such as sacrificial anodes) is recommended.

Pipe Diameter

20mm-1600mm
Wall Thickness

2-20mm optional, to meet different pressure requirements.
Material

Q235B, Q345B
Anticorrosion layer thickness

General bottom epoxy powder 0.1-0.3mm, intermediate adhesive 0.1-0.2mm, outer polyethylene 1.8-3.7mm.
Coating adhesion

More than 100N/cm to ensure strong coating.
Impact resistance

Above 5J, strong resistance to external impact.
Compressive strength

It can withstand certain pressure and meet the requirements of pipeline operation.
Execution standard

GB/T 23257-2017, ISO, ASTM
Service life

Up to 20-50 years under normal environment.
Connection

Welding, flange connection, groove connection, etc.

Theoretical Weight

1、Theoretical weight LSAW steel pipe theoretical weight table:
OD: mm
Wall thickness: mm
Theoretical weight: Kg/m

OD/WT 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5
32 1.82 2.15 2.46 2.76 3.05 3.33 3.59 3.85 4.09 4.32 4.53
38 2.19 2.59 2.98 3.35 3.72 4.07 4.41 4.74 5.05 5.35 5.64
42 2.44 2.89 3.35 3.75 4.16 4.56 4.95 5.33 5.69 6.04 6.38
45 2.62 3.11 3.58 4.04 4.49 4.93 5.36 5.77 6.17 6.56 6.94
50 2.93 3.48 4.01 4.54 5.05 5.55 6.04 6.51 6.97 7.42 7.86
54 – 3.77 4.36 4.93 5.49 6.04 6.58 7.10 7.61 8.11 8.60
57 – 4.00 4.62 5.23 5.83 6.41 6.99 7.55 8.10 8.63 9.16
60 – 4.22 4.88 5.52 6.16 6.78 7.39 7.99 8.58 9.15 9.71
63.5 – 4.48 5.18 5.87 6.55 7.21 7.87 8.51 9.14 9.75 10.36
68 – 4.81 5.57 6.31 7.05 7.77 8.48 9.17 9.86 10.53 11.19
70 – 4.96 5.74 6.51 7.27 8.01 8.75 9.47 10.18 10.88 11.56
73 – 5.18 6.00 6.81 7.60 8.38 9.16 9.91 10.66 11.39 12.11
76 – 5.40 6.26 7.10 7.93 8.75 9.56 10.36 11.14 11.91 12.67
83 – – 6.86 7.79 8.71 9.62 10.51 11.39 12.26 13.12 13.96
89 – – 7.38 8.38 9.38 10.36 11.33 12.28 13.22 14.16 15.07
95 – – 7.90 8.98 10.04 11.10 12.14 13.17 14.19 15.19 16.18
102 – – 8.50 9.67 10.82 11.96 13.09 14.21 15.31 16.40 17.48
108 – – – 10.26 11.49 12.70 13.90 15.09 16.27 17.44 18.59
114 – – – 10.85 12.15 13.44 14.72 15.98 17.23 18.47 19.70
OD/WT 3.0 3.2 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0
(76) 5.40 5.75 6.26 7.10 7.93 8.75 9.56 10.36 11.14 11.91
80 5.69 6.07 6.60 7.49 8.37 9.24 10.07 10.91 11.75 12.59
(83) 5.92 6.31 6.86 7.79 8.71 9.62 10.51 11.39 12.26 13.12
85 6.06 6.46 7.04 7.98 8.93 9.86 10.75 11.65 12.55 13.45
(89) 6.36 6.77 7.38 8.38 9.38 10.38 11.33 12.28 13.22 14.16
90 6.43 6.86 7.47 8.47 9.49 10.47 11.42 12.39 13.35 14.31
95 6.81 7.26 7.90 8.98 10.04 11.10 12.14 13.17 14.19 15.19
100 7.17 7.65 　8.32 9.46 10.59 11.71 12.77 13.87 14.95 16.03
(102) 7.32 7.81 　8.50 9.67 10.82 11.96 13.09 14.21 15.31 16.40
(108) 7.77 8.29 　9.02 10.26 11.49 12.70 13.90 15.09 16.27 17.44
110 7.92 8.43 　9.19 10.46 11.70 12.93 14.19 15.40 16.60 17.75
120 8.66 9.22 10.06 11.44 12.93 14.30 15.51 16.89 18.20 19.50
125 9.02 9.61 10.50 11.91 13.37 14.80 16.15 17.55 19.02 20.35
130 9.40 10.00 10.92 12.43 13.92 15.48 16.88 18.35 19.80 21.20
(133) 9.59 10.25 11.18 12.75 14.26 15.75 17.29 18.79 20.28 21.75
140 10.11 10.79 11.80 13.42 15.05 16.65 18.24 19.83 21.40 22.96
150 10.85 11.52 12.65 14.39 16.11 17.85 19.55 21.25 23.00 24.68
160 – – 13.53 15.38 17.25 19.09 20.96 22.79 24.60 26.41
170 – – 14.31 16.31 18.35 20.30 22.31 24.27 26.21 28.14
180 – – 15.20 17.30 19.50 21.59 23.67 25.75 27.81 29.87
190 – – – 18.29 20.60 22.80 25.02 27.22 29.41 31.59
200 – – – 19.67 21.65 24.00 26.38 28.70 31.02 33.32

 

2、Seamless steel pipe theoretical weight table:
OD: mm
Wall thickness: mm
Theoretical weight: Kg/m

OD/WT 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5
32 1.82 2.15 2.46 2.76 3.05 3.33 3.59 3.85 4.09 4.32 4.53
38 2.19 2.59 2.98 3.35 3.72 4.07 4.41 4.74 5.05 5.35 5.64
42 2.44 2.89 3.35 3.75 4.16 4.56 4.95 5.33 5.69 6.04 6.38
45 2.62 3.11 3.58 4.04 4.49 4.93 5.36 5.77 6.17 6.56 6.94
50 2.93 3.48 4.01 4.54 5.05 5.55 6.04 6.51 6.97 7.42 7.86
54 – 3.77 4.36 4.93 5.49 6.04 6.58 7.10 7.61 8.11 8.60
57 – 4.00 4.62 5.23 5.83 6.41 6.99 7.55 8.10 8.63 9.16
60 – 4.22 4.88 5.52 6.16 6.78 7.39 7.99 8.58 9.15 9.71
63.5 – 4.48 5.18 5.87 6.55 7.21 7.87 8.51 9.14 9.75 10.36
68 – 4.81 5.57 6.31 7.05 7.77 8.48 9.17 9.86 10.53 11.19
70 – 4.96 5.74 6.51 7.27 8.01 8.75 9.47 10.18 10.88 11.56
73 – 5.18 6.00 6.81 7.60 8.38 9.16 9.91 10.66 11.39 12.11
76 – 5.40 6.26 7.10 7.93 8.75 9.56 10.36 11.14 11.91 12.67
83 – – 6.86 7.79 8.71 9.62 10.51 11.39 12.26 13.12 13.96
89 – – 7.38 8.38 9.38 10.36 11.33 12.28 13.22 14.16 15.07
95 – – 7.90 8.98 10.04 11.10 12.14 13.17 14.19 15.19 16.18
102 – – 8.50 9.67 10.82 11.96 13.09 14.21 15.31 16.40 17.48
108 – – – 10.26 11.49 12.70 13.90 15.09 16.27 17.44 18.59
114 – – – 10.85 12.15 13.44 14.72 15.98 17.23 18.47 19.70
OD/WT 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5
121 – – – 11.54 12.93 14.30 15.67 17.02 18.35 19.68 20.99
127 – – – 12.13 13.59 15.04 16.48 17.90 19.32 20.72 22.10
133 – – – 12.73 14.26 15.78 17.29 18.79 20.28 21.75 23.21
140 – – – – 15.04 16.65 18.24 19.83 21.40 22.96 24.51
146 – – – – 15.70 17.39 19.06 20.72 22.36 24.00 25.62
152 – – – – 16.37 18.13 19.87 21.60 23.32 25.03 26.73
159 – – – – 17.15 18.99 20.82 22.64 24.45 26.24 28.02
168 – – – – – 20.10 22.04 23.97 25.89 27.79 29.69
180 – – – – – 21.59 23.70 25.75 27.70 29.87 31.91
194 – – – – – 23.31 25.60 27.82 30.00 32.28 34.50
203 – – – – – – – 29.14 31.50 33.83 36.16
219 – – – – – – – 31.52 34.06 36.60 39.12
245 – – – – – – – – 38.23 41.09 43.85
273 – – – – – – – – 42.64 45.92 49.10
299 – – – – – – – – – – 53.91
325 – – – – – – – – – – 58.74

3、Theoretical weight table of spiral steel pipe:
Outer diameter: mm
Wall thickness: mm
Theoretical weight: Kg/m

OD/WT 5.0 5.5 6.0 7.0 8.0 9.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0 18.0 20.0 22.0
219 26.39 28.96 31.51 36.60 41.63                      
273 33.04 36.28 39.51 45.92                        
325 39.46 43.33 47.26 54.90 62.54 70.13                    
377 45.88 50.39 54.89 63.87 72.80 81.67                    
426 51.91 57.03 62.14 72.33 82.46 92.55 102.59                  
457 55.73 61.24 66.73 77.69 88.58 99.43 110.23 120.98 131.60 142.34            
508     74.28 86.48 98.64 110.75 122.81 134.82 146.78 158.69            
529     77.38 90.11 102.78 115.41 127.99 140.51 152.99 165.42            
559     81.82 95.29 108.70 122.07 135.38 148.65 161.87 175.04            
610     89.37 104.09 118.76 133.39 147.96 162.48 176.96 191.39            
630     92.33 107.54 122.71 137.82 152.89 167.91 182.88 197.80            
660     96.77 112.72 128.63 144.48 160.29 176.05 191.76 207.42            
720     105.64 123.08 140.46 157.80 175.09 192.32 209.51 226.65            
820       140.34 160.19 179.99 199.75 219.45 239.10 258.71 276.26 297.77 317.23 256.01 394.58 432.96
914         178.74 200.06 222.93 244.95 266.92 288.84 310.72 332.54 354.31 397.74 440.95 483.96
920         179.92 202.19 224.41 246.58 268.70 290.77 312.79 334.76 356.68 400.40 443.91 486.13
1016         198.86 223.49 248.08 272.62 297.10 321.54 345.93 370.27 394.56 443.02 491.26 539.30
1020         199.65 224.38 249.07 273.70 298.39 322.82 347.31 371.75 396.14 44.79 493.23 541.47
1220             296.39 327.95 357.47 386.94 416.36 445.73 475.58 533.58 591.88 649.98
1420             347.71 362.21 416.66 451.06 485.41 519.71 553.96 622.36 690.52 758.49
1620             397.03 436.46 475.84 515.17 554.46 593.60 632.87 711.14 789.17 867.00
1820             446.35 490.71 535.02 579.29 623.50 667.67 711.79 799.92 887.81 975.51
2020             495.67 544.96 594.21 643.40 692.55 741.65 796.70 888.70 986.46 1084.21
2220             544.99 599.21 653.39 707.52 761.60 815.63 869.61 977.48 1085.11 1192.53

Process flow

Base pipe inspection → Shot blasting rust removal → Medium frequency preheating → Epoxy powder spraying → Adhesive extrusion → Polyethylene coating → Water cooling shaping → Online inspection → Pipe end treatment → Finished product inspection → Spray coding identification → Packaging and storage

3PE Corrosion-Resistant Steel Pipe Manufacturing Process

FAQ – 3PE Anti-Corrosion Steel Pipes

1. What is the corrosion resistance of 3PE anti-corrosion steel pipe in different environments (underground, seawater, acidic and alkaline soil)?
3PE anti-corrosion steel pipes provide excellent protection in a wide range of environments. Underground installations in normal soil maintain a service life of 30–50 years. Seawater or highly corrosive soils may accelerate aging, but the three-layer coating (FBE + adhesive + HDPE) ensures long-term durability. For extreme conditions, additional protection or higher-grade coatings can be applied.

2. What is the thickness and grade of the 3PE anti-corrosion layer?
The 3PE coating consists of three layers:
   FBE epoxy primer: typically ≥ 150 μm
   Adhesive layer: 0.1–0.3 mm
   HDPE outer layer: 2.0–3.5 mm
The grade can be selected based on environmental conditions: C1 (light corrosion) to C4 (highly corrosive), ensuring adequate protection for specific project needs.

3. How are the welded joints of 3PE anti-corrosion steel pipes protected against corrosion?
Welded joints are vulnerable to corrosion. Engineers apply heat-shrink sleeves, liquid epoxy coatings, or tape coatings to cover welded areas, ensuring continuity of the anti-corrosion system and preventing corrosion entry points.

4. How does the internal medium affect the lifespan of 3PE anti-corrosion steel pipes?
Highly corrosive media, such as hydrogen sulfide, acidic water, or high-salt wastewater, can accelerate internal corrosion. To prevent damage, internal protective coatings like IPN8710 are recommended, which significantly extend the pipe’s service life.

5. How should installed 3PE anti-corrosion steel pipes be inspected and maintained?
Regular maintenance ensures long-term performance. Recommended practices include:
Leak detection scans
Peel adhesion testing
Visual inspection of exposed joints and bends
Timely repair of damaged coatings or protective layers can extend the service life by over 10 years.

6. Is 3PE anti-corrosion steel pipe suitable for long-distance underground transmission?
Yes. The three-layer coating provides strong mechanical protection and corrosion resistance, making 3PE pipes ideal for long-distance underground pipelines in municipal water supply, oil & gas, and chemical industries.

7. What are the international and domestic standards for 3PE anti-corrosion steel pipes? How do I choose the appropriate standard?
Domestic standards: GB/T 9711, SY/T 5037
International standards: API 5L, ISO 3183, DIN 30670, EN 10208
Selection tip: Choose the standard based on project location, regulatory requirements, operating pressure, and medium type.

8. What are the advantages and limitations of 3PE anti-corrosion steel pipes compared to other anti-corrosion pipes (such as FBE, epoxy-coated pipes, and hot-dip galvanized pipes)?
Advantages:
Superior mechanical and corrosion protection
Long service life (30–50 years) under standard conditions
Excellent performance in underground and high-corrosion environments
Limitations:
Higher cost compared to simple FBE or epoxy coatings
Requires careful handling during transport and installation to avoid coating damage
Limited temperature range for polyethylene outer layer (stable up to 120°C, accelerated aging above 80°C)

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