This page provides ERW pipe size chart and standard dimension reference for structural, construction, and industrial applications. You can review common ERW steel pipe sizes including outside diameter, wall thickness, and length range.
For manufacturing details and commercial supply information, please visit our ERW steel tube product page.
ERW Pipe Dimensions Overview
ERW (Electric Resistance Welded) pipes are widely used in structural engineering, water transportation, fencing, scaffolding, and general industrial fabrication. Compared with seamless pipes, ERW pipes are often selected for cost efficiency and large-volume structural use.
This page focuses on ERW pipe dimensions and size reference. For pressure-related pipe systems, you may also check our seamless steel pipe solutions.
| DN | Out Diameter | Thickness Chart | |||||||||||||||
| A series | B series | Sch 5s | Sch 10s | Sch 20s | LG | Sch 20 | Sch 30 | STD | Sch 40 | Sch 60 | XS | Sch 80 | Sch 100 | Sch 120 | Sch 140 | Sch 180 | |
| 32 40 50 | 42.4 48.3 60.3 | 38 45 57 | 1.6 1.6 1.6 | 2.8 2.8 2.8 | 3.2 3.2 3.6 | - - - | - - 3.2 | - - - | - - - | 3.6 3.6 4.0 | - - - | - - - | 5.0 5.0 5.6 | - - - | - - - | - - - | 6.3 7.1 8.8 |
| 65 80 90 | 76.1 88.9 101.6 | 76 89 - | 2.0 2.0 2.0 | 3.0 3.0 3.0 | 3.6 4.0 4.0 | - - - | 4.5 4.5 4.5 | - - - | - - - | 5.0 5.6 5.6 | - - - | - - - | 7.1 8.0 8.0 | - - - | - - - | - - - | 10.0 11.0 12.5 |
| 100 125 150 | 114.3 139.7 168.3 | 108 133 159 | 2.0 2.9 2.9 | 3.0 3.4 3.4 | 4.0 5.0 5.0 | - - - | 5.0 5.0 5.6 | - - - | - - - | 5.9 6.3 7.1 | - - - | - - - | 8.8 10.0 11.0 | - - - | 11.0 12.5 14.2 | - - - | 14.2 16.0 17.5 |
| 200 250 300 | 219.1 273.0 323.9 | 219 273 325 | 2.9 3.6 4.0 | 4.0 4.0 4.5 | 6.3 6.3 6.3 | - - - | 6.3 6.3 6.3 | 7.1 8.0 8.8 | - - - | 8.0 8.8 10.0 | 10.0 12.5 14.2 | - - - | 12.5 16.0 17.5 | 16.0 17.5 22.2 | 17.5 22.2 25.0 | 20.0 25.0 28.0 | 22.2 28.0 32.0 |
| 350 400 450 500 550 600 | 355.6 406.4 457.0 508.0 559 610 | 377 426 478 529 - 630 | 4.0 4.0 4.0 5.0 5.0 5.6 | 5.0 5.0 5.0 5.6 5.6 6.3 | - - - | 8.0 8.0 8.0 8.0 8.0 8.0 | 8.0 8.0 8.0 10.0 - - | 10.0 10.0 11.0 12.5 - - | 10.0 10.0 10.0 10.0 10.0 10.0 | 11.0 12.5 14.2 16.0 - 17.5 | 16.0 17.5 20.0 20.0 - - | 13.0 13.0 13.0 13.0 13.0 13.0 | 20.0 22.2 25.0 28.0 30.0 32.0 | 25.8 28.5 30.0 32.0 - - | 28.0 30.0 36.0 40.0 - - | 32.0 36.0 40.0 45.0 - - | 36.0 40.0 45.0 50.0 - - |
Looking for detailed dimensions, schedule charts, wall thickness tables, and weight data? View the complete ERW Pipe Specifications & Size Chart Guide.
| NPS (inch) | Outer Diameter(mm) | SCH 5 | SCH 10 | SCH 40 / STD | SCH 80 / XS | ||||
|---|---|---|---|---|---|---|---|---|---|
| WT (mm) | Wt (kg/m) | WT (mm) | Wt (kg/m) | WT (mm) | Wt (kg/m) | WT (mm) | Wt (kg/m) | ||
| 1/2" | 21.3 | 1.65 | 0.81 | 2.11 | 1.01 | 2.77 | 1.29 | 3.73 | 1.62 |
| 3/4" | 26.7 | 1.65 | 1.03 | 2.11 | 1.30 | 2.87 | 1.71 | 3.91 | 2.20 |
| 1" | 33.4 | 1.65 | 1.31 | 2.77 | 2.12 | 3.38 | 2.54 | 4.55 | 3.29 |
| 1¼" | 42.2 | 1.65 | 1.93 | 2.77 | 3.15 | 3.68 | 3.48 | 4.85 | 4.47 |
| 1½" | 48.3 | 1.65 | 1.93 | 2.77 | 3.15 | 3.68 | 4.05 | 5.08 | 5.41 |
| 2" | 60.3 | 1.65 | 2.42 | 2.77 | 3.98 | 3.91 | 5.44 | 5.54 | 7.48 |
| 2½" | 73.0 | — | — | — | — | 5.16 | 8.63 | 7.01 | 11.41 |
| 3" | 88.9 | 2.11 | 4.58 | 3.05 | 6.54 | 5.49 | 11.29 | 7.62 | 15.27 |
| 3½" | 101.6 | 2.11 | 5.25 | 3.05 | 7.52 | 5.74 | 13.77 | — | — |
| 4" | 114.3 | 2.11 | 5.25 | 3.05 | 7.52 | 6.02 | 16.07 | 8.56 | 22.32 |
| 5" | 141.3 | 2.77 | 9.50 | 3.40 | 11.74 | 6.55 | 21.77 | 9.53 | 30.97 |
| 6" | 168.3 | 2.77 | 11.47 | 3.40 | 14.04 | 7.11 | 28.25 | 10.97 | 42.56 |
| 8" | 219.1 | 2.77 | 14.99 | 3.76 | 20.25 | 8.18 | 42.55 | 12.70 | 64.64 |
| 10" | 273.0 | — | — | — | — | 9.27 | 60.29 | 15.09 | 94.79 |
| 12" | 323.8 | — | — | — | — | 10.31 | 79.62 | 17.48 | 128.07 |
The weight calculation of ERW steel pipe is usually based on the theoretical weight formula for steel pipe. Since ERW steel pipe is a welded pipe, its calculation is the same as that of seamless steel pipe, both calculated based on the principle of unfolding a round pipe into a steel strip.
W (kg/m) = 0.02466 × T × (D − T)
Where:
W = Theoretical weight per meter (kg/m)
T = Steel pipe wall thickness (mm)
D = Steel pipe outer diameter (mm)
0.02466 = Density coefficient of steel pipe material, applicable to ordinary carbon steel, density is taken as 7.85 g/cm³
| Size Classification | Outer Diameter Range | Wall Thickness Characteristics | Main Applications |
| Small Diameter Pipe | 21.3 - 114.3 mm (Approx. 1/2 - 4 inches) | Thinner, typically 2.0 - 6.0 mm | - Water and gas pipelines in buildings - Branch pipes for fire sprinkler systems - Furniture and scaffolding structures - Mechanical parts |
| Medium Diameter Pipe | 114.3 - 323.9 mm (Approx. 4 - 12 inches) | Moderate, typically 4.0 - 12.7 mm | - Urban water supply and heating networks - Oil and gas gathering and transmission pipelines - Building structural support columns - General industrial fluid transportation |
| Large Diameter Pipe | 323.9 - 610 mm (Approx. 12 - 24 inches) | Thicker, up to 19.1 mm | - Long-distance oil and gas trunk pipelines - Marine engineering and structural pile foundations - Large-scale water conservancy and industrial circulating water systems - Municipal main pipeline network |
Notes:
The ERW pipe dimensions above are provided for reference only. Actual size range and tolerance may vary according to production standard and application requirement.
If you need complete size availability, please contact our ERW pipe supplier team for confirmation.
ERW pipe dimensions are generally specified by outside diameter and wall thickness. Different standards may apply depending on structural, fluid, or industrial usage.
Buyers should confirm:
Diameter range
Thickness range
Weld specification
Surface treatment
Length requirement
Application environment
For galvanized applications, you may also review our galvanized steel tube dimension resources.
Advantages of ERW Steel Pipe
ERW steel pipes offer a balanced combination of performance, cost efficiency, and production consistency, making them widely used in various industries.
Cost-effective
Compared with seamless pipes, ERW pipes are more economical due to a more efficient manufacturing process and lower material waste.
Good dimensional accuracy
ERW pipes are produced with tight tolerances, ensuring consistent outer diameter and wall thickness.
Suitable for high-volume projects
The continuous production process allows for large-scale manufacturing with stable quality.
Oil and gas transportation – suitable for low to medium pressure pipeline systems
Water pipelines – used in municipal and industrial fluid transport
Structural applications – applied in construction, scaffolding, and mechanical structures
Q1: What is the difference in wall thickness between ERW pipe and seamless pipe?
A1: Under the same specification, the wall thickness of ERW pipe is more uniform (controlled by cold rolling process), but seamless pipe can produce thicker wall.
Q2: Is ERW pipe strong?
A2: Yes. ERW pipes offer reliable mechanical strength and are suitable for most standard pressure and structural applications when manufactured to standards such as API 5L or ASTM A53.
Q3: Can ERW pipes be supplied with coating?
A3: Yes. Available options may include 3PE coating, FBE coating, black painting, bitumen coating, and galvanized finish based on project requirements.
Q4: Does the wall thickness of galvanized ERW pipe need to be increased?
A4: No, the effect of the galvanized layer (50~100μm) on strength can be ignored, but attention should be paid to the adhesion of the zinc layer.
Q5: How to detect the wall thickness of ERW pipe?
A5: Ultrasonic thickness gauge (UT) or caliper measurement (avoid the weld area).
Q6: Can you provide custom sizes and lengths?
A6: Yes. Custom diameters, wall thicknesses, lengths, and end finishes can be produced depending on order quantity and technical requirements.
Request ERW Pipe Quotation
Need quotation based on specific ERW pipe dimensions? Send us your required OD, thickness, length, and application details.
You can also submit inquiries through our ERW steel tube contact page for faster support.
