ERW Welded Pipe
Features of ERW Welded Pipe
1.Uniform wall thickness (tolerance ±0.2 mm).
2.High dimensional accuracy and smooth surface finish.
3.Minimal residual stress due to controlled forming and sizing.
4.Weld seam length equal to pipe length, reducing defect probability compared to spiral welds.
5.Available in circular and rectangular profiles (e.g., 100×50 mm) with outer diameters from φ20mm to φ610mm and wall thicknesses
from 2mm to 36mm.
Technical Advantages of ERW Welded Pipe
Compared to seamless steel pipes, ERW pipes offer:
1.Superior outer diameter control (±0.5% tolerance) due to cold-forming at ambient temperature.
2.Lower production cost and higher efficiency (up to 200 m/min welding speed).
3.Better surface quality for coating adhesion and corrosion protection.
4.Consistent mechanical properties after post-weld heat treatment (e.g., normalizing).
5.Compliance with international standards including API 5L, GB/T 9711, and newly approved ISO/AWI 26340 for groove corrosion testing.
Primary Applications of ERW Welded Pipe
1.Oil & Gas Transportation: Onshore and offshore pipelines operating at pressures of 4-12 MPa; used for natural gas, crude oil, and refined products.
2.Construction & Infrastructure: Structural supports for bridges, piling, docks, roads, and building frameworks.
3.Hydraulic Systems: Cold-drawn ERW tubes serve as precision cylinders for multi-stage hydraulic rams, achieving tensile strengths >600 MPa and surface roughness Ra <0.4 μm.
4.Water & Utility Networks: Municipal water supply, industrial process piping, and drainage systems.
5.Automotive & Machinery: Transmission shafts, steering rods, and fuel tanks requiring high precision and corrosion resistance
Comparison between ERW Welded Pipe and Seamless Pipes
Feature | ERW Pipe | Seamless Pipe |
|---|---|---|
Manufacturing Process | Cold-forming + electric resistance welding | Hot piercing + rolling |
Outer Diameter Tolerance | ±0.5% (high precision) | ±1-2% (variable due to thermal expansion) |
Wall Thickness Uniformity | ±10% (modern strips: ±0.05 mm) | Higher deviation due to perforation |
Production Speed | Up to 200 m/min | Slower, batch-based |
Cost Efficiency | Lower material and energy consumption | Higher raw material and energy cost |
High-Pressure Suitability | Suitable up to 12 MPa | Preferred for >15 MPa and extreme environments (e.g., deep sea, high temp) |
