Tianjin Brisk Steel is one of the manufacturers of Bare LSAW Steel Pipe in China. Our products are mainly exported to the Middle East, Southeast Asia, Europe, New Zealand, and other regions.If you would like to learn more about our products, feel free to contact us and send your purchase list.
The Pipe Body Before The Coating
A coating is only as good as the steel it's bonded to. Order the coating first and the pipe body as an afterthought, and you inherit whatever dimensional inconsistencies or weld defects the mill didn't catch - problems that surface later as coating adhesion failures nobody can trace back to their real cause. LSAW (Longitudinally Submerged Arc Welded) steel pipe is where a reliable pipeline actually starts, whether you're coating it yourself, sending it to a coating subcontractor, or running it bare in a controlled environment.
We supply LSAW pipe as a standalone product - for clients applying their own FBE, 3PE, or 3PP systems, for coating shops sourcing pipe bodies, and for applications where a protective coating isn't part of the spec at all.
Why LSAW, Not Spiral Welded (SSAW), for Large-Diameter Lines
Both processes weld steel into pipe. They are not interchangeable for high-pressure, large-diameter service, and the difference shows up in the weld seam:
- Straight longitudinal seam vs. spiral seam. LSAW pipe is formed from a single flat plate pressed into a U, then an O, then welded along one straight seam. SSAW pipe spirals a steel coil into shape, creating a longer, helical weld path with more opportunity for defects.
- Tighter dimensional tolerance. Plate-formed LSAW pipe holds roundness and wall thickness consistency better than coil-formed spiral pipe, especially at larger diameters and heavier wall thickness.
- Higher pressure rating at the same wall thickness. The straight seam and thicker starting plate let LSAW pipe handle higher-pressure transmission service without over-specifying wall thickness.
- Preferred for thick-wall applications. Above roughly 12mm wall thickness, LSAW becomes the practical standard - SSAW mills struggle to maintain weld quality at that plate thickness.
If your project is high-pressure oil, gas, or long-distance water transmission at 16" OD or larger, LSAW is almost always the spec - check your project's API 5L requirement before assuming SSAW is an acceptable substitute.
How to turn a plate into a tube
- Plate inspection. Incoming steel plate is checked for thickness, chemical composition, and surface defects before it enters forming.
- JCOE or UOE forming. The plate is progressively pressed - J-shape, then C, then O - into a cylindrical pipe body, with UOE forming (adding an expansion step) used for tighter roundness tolerance on critical applications.
- Submerged arc welding, inside and outside. Both the internal and external weld passes are done under a flux layer that shields the weld from atmospheric contamination - this is where "submerged arc" gets its name.
- 100% ultrasonic and X-ray weld inspection. Every meter of weld seam is checked, not sampled, because a missed defect here becomes a pipeline failure later.
- Hydrostatic testing. Each pipe is pressure-tested above its rated operating pressure before it's cleared to ship.
- End facing and beveling. Pipe ends are machined to the bevel angle specified for field girth welding.
Specifications
| Specification | Detail |
|---|---|
| Standard | API 5L |
| Grade | B, X42, X46, X52, X56, X60, X65, X70, X80 |
| Outer Diameter | 406mm – 1420mm |
| Wall Thickness | 6mm – 40mm |
| Length | 6m, 12m, or double random per client requirement |
| Testing | 100% UT/X-ray weld inspection, hydrostatic test, mechanical property testing per heat |
| Surface Condition | Mill finish, ready for FBE, 3PE, or 3PP coating application |
FAQ
Q:What's the maximum diameter available in LSAW pipe?
A:Most LSAW mills produce up to 1626mm (64") OD, though the practical upper limit depends on wall thickness and steel grade - confirm availability against your exact spec before finalizing a project timeline.
Q: Can I order LSAW pipe without any coating at all?
A: Yes. Bare, mill-finish LSAW pipe is a standard product for clients who coat in-house, use the pipe in non-corrosive environments, or require a different coating system than what we apply directly.
Q: How is LSAW pipe tested before shipment?
A: Standard testing includes 100% ultrasonic and X-ray inspection of the weld seam, hydrostatic pressure testing of every pipe, and mechanical property verification (tensile, yield, Charpy impact) per heat number, all documented in mill test certificates.
Q: What grades are available for high-pressure gas transmission?
A: X60 through X80 are the common grades specified for high-pressure gas transmission lines, chosen based on the project's design pressure and wall thickness calculations per API 5L / ISO 3183.
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