Welded Steel Pipes — ERW, LSAW and SSAW Guide
How electric-resistance welded, longitudinal submerged-arc welded and spiral submerged-arc welded pipes are made, tested and specified for structural, fluid and mechanical service.
Start here
Welded steel pipe is coil or plate rolled into a cylinder and joined along a single seam. ERW is fast and economical for smaller diameters; LSAW handles thicker walls and higher pressures; SSAW covers the largest diameters at competitive cost. Each has its own domain — pick the wrong one and the price, weight or pressure rating misses the mark.
This pillar page walks through the three welding routes, the mechanical envelope for each, and the inspection standards that guarantee the pipe you receive matches the pipe you specified.
Go to product rangeHow it's made
ERW forming
Steel coil is roll-formed into a tube and welded along the longitudinal seam by high-frequency electric current — no filler metal.
LSAW forming (JCOE/UOE)
Heavy plate is pressed into a U then O, and submerged-arc welded inside and out along the straight seam.
SSAW forming
Coil is helically formed and submerged-arc welded along the spiral seam — ideal for large diameters.
Inspection & finishing
100% ultrasonic seam inspection, hydrostatic testing to API 5L, end bevelling, coating and marking per spec.
Where it's used
- Oil & gas transmission pipelines
- Water supply & sewage networks
- Structural columns & scaffolding
- Piling & foundation casings
- Fire protection & sprinkler systems
- HVAC & compressed-air distribution
- Handrails, fencing & general fabrication
- Automotive & agricultural tubing
Why buyers specify it
Cost-effective at scale
Welded pipe costs 20–40% less than equivalent seamless pipe — the go-to choice wherever a seam is acceptable.
Wide diameter & wall range
One factory covers 21 mm ERW to 3,000 mm SSAW — a single supplier for a full pipeline BOM.
100% seam inspection
Every metre of weld is ultrasonically inspected; hydrotest and radiography available on request.
Coated and ready to install
3LPE, FBE or epoxy coatings applied in-line — pipe arrives ready for burial or installation.
Codes we build to
- API 5L PSL1/PSL2 line pipe
- ASTM A53 / A252 structural pipe
- ASTM A500 / A501 hollow structural sections
- EN 10217 & EN 10219 welded pipe
- AWWA C200 water transmission pipe
- GB/T 3091 & GB/T 9711 (China)
Technical envelope
Diameter (ERW) | OD 21.3 mm – 660 mm |
|---|---|
Diameter (LSAW) | OD 406 mm – 1,626 mm |
Diameter (SSAW) | OD 219 mm – 3,048 mm |
Wall thickness | 1.5 – 40 mm depending on process |
Grades | Q195/Q235/Q345, S235JR/S355JR, API 5L B/X42-X70, ASTM A53/A252/A500 |
Length | Random 6–12 m; fixed length on request |
Specify with confidence
Match diameter to process
ERW for OD ≤ 660 mm, LSAW for medium-large heavy walls, SSAW for very large diameters at low cost.
Pick the grade
Q235/S235 for general structure; Q345/S355 for higher load; API 5L X-grades for pressure and pipeline service.
Specify the end
Plain end for coupling, bevelled end for welding, threaded & coupled for fluid distribution. State weld map if you need matched heats.
Add coating & marking
3LPE for buried oil & gas, FBE for water, black or galvanised for structure. Marking per API 5L or your buyer's standard.
Common questions
The questions our sales engineers hear most often about this product family.
Datasheets & guides
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