Electric Resistance Welded Steel Pipe (ERW pipe) is a straight-seam welded steel pipe made by heating and welding steel strips using high-frequency resistance welding. Also called straight-seam resistance-welded pipe. Compared with seamless steel pipes, it has higher precision and lower cost, and is widely used in construction, oil and gas transportation, and urban pipeline networks.
Glory Steel, as a leading ERW pipe manufacturer in China, possesses advanced welding production lines. It can produce pipes with outer diameters ranging from OD 20mm – 610mm and wall thicknesses from 2.0mm to 20mm, and can perform post-processing processes such as oil coating, galvanizing, PE coating, and threading.
Specification
| Item | ERW pipe |
|---|---|
| Material | Q195/Q235/Q345/Q355, St 37/52, ASTM A53 HR/CR Steel Coil |
| Dimensions | OD: 20mm – 610mm |
| WT: 2.0mm – 20mm | |
| Length: 6–12 meters (39.37 ft) | |
| Special Pipe | API Pipe, EMT Pipe, Thick Wall Pipe, Other |
| Certificate | API, SNI, JIS, ISO 9001 |
| Technique | Hot Rolled / Cold Rolled |
| Standard | API 5L, ASTM A53, ASTM A106, GB/T 9711, EN 10217 |
| Place of Origin | Tianjin, China |
| Delivery Time | 15–21 days |
ERW Pipe Size Representation
US Standard (ASTM / API)
- Nominal Pipe Size (NPS): in inches, e.g. 1/2″, 1″, 2″
- Wall Thickness: SCH 10 / SCH 40 / SCH 80 (higher number means thicker wall) | BWG 14 / BWG 16 (lower number means thicker wall)
- Can also be marked directly as OD + WT (mm / inch)
European Standard (EN / BS)
- Nominal Diameter (DN): in millimeters, e.g. DN15, DN50
- Wall Thickness: S series (S1/S2/S3) or direct mm value
- Structural pipes: usually marked as OD × WT × Length
Chinese Standard (GB)
- Fluid pipes: DN + Wall Thickness (mm)
- Structural pipes: marked directly as OD × WT (mm)
- NPS / SCH marking is also acceptable for export
Size Comparison Table
| NPS | DN | OD(mm) | SCH40 (mm) | EN/GB (mm) |
|---|---|---|---|---|
| 1/2″ | 15 | 21.3 | 2.77 | 2.3 / 2.75 |
| 3/4″ | 20 | 26.9 | 2.87 | 2.6 / 2.75 |
| 1″ | 25 | 33.7 | 3.38 | 3.2 / 3.25 |
| 1.25″ | 32 | 42.4 | 3.56 | 3.2 / 3.25 |
| 1.5″ | 40 | 48.3 | 3.68 | 3.2 / 3.5 |
| 2″ | 50 | 60.3 | 3.91 | 3.2 / 3.8 |
| 3″ | 80 | 88.9 | 5.49 | 4.0 |
| 4″ | 100 | 114.3 | 6.02 | 4.0 |
| 6″ | 150 | 168.3 | 7.11 | 4.0 |
Notes
- NPS: Nominal Pipe Size (US, Middle East, Southeast Asia).
- DN: Nominal Diameter (Europe, China, Australia).
- OD: Outside Diameter (universal worldwide).
- SCH40: Standard wall thickness in the US system.
- EN/GB: Common wall thickness for European & Chinese standards.
Key Features
1. Advanced Production Technology
ERW pipes are produced through an electric resistance welding process, using hot-rolled or cold-rolled low-carbon steel coils as raw materials.The welding process ensures stable mechanical properties and reliable quality.
2. High Dimensional Accuracy & Smooth Surface
No extra welding materials are needed during production.The pipes have uniform chemical composition, precise dimensions, and smooth surface, which is good for coating adhesion.
3. Various Surface Treatment Options
Glory Steel provides multiple surface treatments:
- Black pipe
- Galvanized pipe
- Painted / Epoxy / PE coated pipeWe can supply API 5L pipes, EMT pipes, and other special types.
4. Cost-Effective & Customizable
ERW production line features high welding speed (20–200 meters per minute) and low material loss.Sizes, length, material grade, and surface treatment can be customized according to project requirements.
Application Areas
- Oil and Gas Transportation: ERW straight seam welded pipe is one of the mainstream pipe types in natural gas, crude oil, and petroleum product (API 5L grade) pipelines, often used alongside spiral submerged arc welded pipe (SSAW) and straight seam submerged arc welded pipe (LSAW).
- Building Structures: High-rise building frames, bridge load-bearing structures, piling projects, and scaffolding pipes, etc.
- Municipal Pipelines: ERW steel pipes are widely used in urban gas, heating, and water supply and drainage systems due to their good sealing performance and high pressure resistance.
- Industrial Pipelines: Process pipelines in chemical plants, power plants, and mines; furniture and sports equipment pipes, etc.
ERW Steel Pipe Selection Comparison Table
| DN | OD (mm) | WT (mm) | Length(m) | Uses |
|---|---|---|---|---|
| DN15 | 21.3 | 2.75 | 4-12 | Low-pressure fluids such as water and gas |
| DN20 | 26.9 | 2.75 | 4-12 | Municipal pipelines and conduits |
| DN25 | 33.7 | 3.25 | 4-12 | Water supply and drainage, heating and ventilation systems |
| DN50 | 60.3 | 3.6 | 4-12 | Industrial fluid transport |
| DN80 | 88.9 | 4.0-5.0 | 6-12 | Oil and gas transportation |
| DN100 | 114.3 | 4-16 | 6-12 | Main pipelines and structural supports |
| DN150 | 168.3 | 6-12 | 6-12 | High-flow-rate conveying, bridge pipe |
| DN200 | 219.1 | 6-22 | 6-12 | High-pressure fluid, urban main grid |
| DN300 | 323.9 | 8-22 | 6-12 | Long-distance pipelines and industrial pipelines |
| DN400 | 406.4 | 8-22 | 6-12 | Large-diameter conveying and pile foundation |
Our ERW Pipe Categories
1. By Material
- Carbon Steel ERW Pipes
- Alloy Steel ERW Pipes (including Low Alloy Steel)
- Stainless Steel ERW Pipes
2. By Surface Treatment
- ERW Black Steel Pipes (Bare Pipe)
- ERW Galvanized Steel Pipes (Hot Dip Galvanized)
- ERW Pre-Galvanized Pipes
- ERW Coated / Painted Pipes (3PE/FBE/Epoxy)
- 3PE: 3-layer Polyethylene Coating; FBE: Fusion Bonded Epoxy
3. By Standard & Application
- API 5L ERW Pipes: Line Pipe for Oil & Gas.
- ASTM A53 ERW Pipes: General Fluid Service.
- GB/T 3091 ERW pipe: Low-pressure fluid (water, gas) transportation.
- ASTM A500 ERW Structural Pipes: Construction & Structure.
- Boiler Tubes: High Temperature & Pressure.
- Scaffolding Tubes: Construction Scaffolding.
- Greenhouse Tubes: Agricultural Greenhouse.
- Thick Wall ERW Pipes: Heavy Duty Structure.
- EMT / IMC / RMC Conduit: Electrical Conduit, Non-Fluid Use.
- EMT: Electrical Metallic Tubing; IMC: Intermediate Metal Conduit; RMC: Rigid Metal Conduit
4. By Shape
- ERW Round Tubes
- ERW Square Tubes
- ERW Rectangular Tubes
Manufacturing Process of ERW Steel Pipe
Hot-rolled/cold-rolled steel coils → slitting into strips → edge treatment & butt welding → roll bending → high-frequency welding → deburring (internal & external) → sizing & straightening → non-destructive testing & hydrostatic testing → length cutting → surface treatment → marking & packaging.
- Forming technologies: Commonly include FFX flexible forming and URD forming. The former is suitable for various specifications, while the latter is suitable for medium and large diameter pipes.
- Welding methods: Divided into contact welding and induction welding, with frequencies generally between 350-450 kHz; the weld is formed by the fusion of the base material itself.
- Surface treatment: galvanizing, black paint coating, 3PE anti-corrosion coating, etc.
- Non-destructive testing: Ultrasonic testing (UT) and eddy current testing (ET), and hydrostatic testing according to standard requirements. End treatment: Can be finished with flat ends, chamfering, threads, and pre-welded flanges.
Why Choose Our ERW Steel Pipes?
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Glory Steel Plant, located in Tianjin, China, is an ISO 9001, ISO 14001, and CE certified factory with an annual output of 100,000 tons. We specialize in producing galvanized pipes, stainless steel pipes, and alloy steel pipes. With our high-quality products and services, we export to over 120 countries.
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