Differences between ERW and LSAW steel pipes
When selecting steel pipes for large-scale oil, gas, and water transmission projects, two common types are ERW (Electric Resistance Welded) pipes and LSAW (Longitudinal Submerged Arc Welded) pipes.Each type has distinct features, manufacturing processes, and application scenarios. At Haihao Group, with decades of production and export experience, we help you understand these differences to make the best choice for your project.
Haihao ASME B36.10 ASTM A53 GR.B ERW pipe manufacturing line for oil and gas projects
Quick Comparison Table: ERW vs. LSAW Steel Pipes
| Feature | ERW Steel Pipes | LSAW Steel Pipes |
|---|---|---|
| Manufacturing Process | High-frequency electric resistance welding of hot-rolled coils | Submerged arc welding of medium-thick single steel plates |
| Pipe Shape | Continuous, rolled from coil strips | Individually formed and welded from steel plates |
| Weld Type | Single straight weld seam | Double-sided weld seam using SAW |
| Diameter Range | Small to medium (up to 24 inches) | Medium to large (up to 56 inches or more) |
| Wall Thickness | Thinner walls | Suitable for thick-wall pipes |
| Length Accuracy | Higher dimensional precision | Slight variation, requires post-processing sizing |
| Surface Finish | Smooth surface due to coil-based production | May require grinding or additional finishing |
| Pressure Tolerance | Ideal for moderate pressure pipelines | Suitable for high-pressure, high-load applications |
| Application Examples | Urban water supply, heating pipelines, general oil transport | Long-distance gas pipelines, subsea pipelines, structural columns |
| Cost | Lower production cost | Higher cost due to complex process |
What is ERW Steel Pipe?
ERW pipes are made by cold-forming steel coils into a cylindrical shape, followed by high-frequency electric resistance welding. The result is a pipe with a short, direct weld seam running longitudinally.
Advantages:
- Precise diameter control
- Smooth surface finish
- Lower weight, easier handling
Limitations:
- Restricted to thinner walls
- Not suitable for extreme pressure or offshore deep-sea applications
High-diameter LSAW pipe supplied by Haihao for offshore LNG project
What is LSAW Steel Pipe?
LSAW pipes are produced by bending and welding individual steel plates using submerged arc welding technology. This method produces pipes of larger diameter and thicker walls, suitable for heavy-duty projects.
Advantages:
- High strength and durability
- Consistent weld quality on both sides
- Good for high-pressure or corrosive environments
Limitations:
- Higher production cost
- Heavier weight requires more transport and installation effort
Real Project Applications from Haihao Group
ERW Pipes for City Gas Pipeline Projects in Southeast Asia: Haihao’s ASTM A53 Grade B ERW pipes have been successfully delivered for urban natural gas projects in Singapore and Malaysia, providing efficient and reliable service in city-wide distribution networks.
LSAW Pipes for Oil and Gas Transmission to the Middle East: Haihao’s LSAW pipes—manufactured in accordance with API 5L and DNV standards—are used in high-pressure oil transmission pipelines in Qatar’s LNG export terminals, ensuring durability under harsh desert and offshore conditions.
Frequently Asked Questions (FAQ)
Q1: Which pipe type is better for offshore oil platforms?
A: LSAW pipes are recommended for offshore applications because of their high strength, double-weld seams, and corrosion resistance.
Q2: Are ERW pipes acceptable for high-pressure gas pipelines?
A: Generally no—ERW pipes are more suitable for low to medium pressure. LSAW or seamless pipes are preferred for high-pressure, long-distance gas transmission.
Q3: How does Haihao ensure pipe quality?
A: All products are tested to API, ASTM, and ASME standards with third-party inspections (SGS, BV) and full mill certificates.
Haihao Group offers both ERW and LSAW steel pipes backed by certified manufacturing processes, international shipping experience, and customized technical support. Whether you need precision ERW pipes for municipal projects or robust LSAW pipes for cross-border energy pipelines, our team ensures reliable performance and top-quality delivery.