Direct answer
Spiral (SSAW) pipe has a helical seam, is formed from coil and suits large diameter water mains, piling and structural work, 273 to 3,600 mm OD. LSAW pipe has one straight seam, is formed from plate and is chosen where the specification wants one short seam per pipe, 300 to 2,500 mm OD. Gram Bangla Tubes Ltd (GBTL) makes both.
At a glance
| Point | Spiral (SSAW) pipe | LSAW pipe |
|---|---|---|
| Seam | Helical seam, submerged arc welded inside and outside | One straight seam, submerged arc welded inside and outside |
| Raw material | Hot rolled steel coil | Steel plate |
| GBTL outside diameter | 273 to 3,600 mm | 300 to 2,500 mm |
| GBTL wall thickness | 3.0 to 25.0 mm | 3.0 to 17.0 mm |
| Usual uses | Water transmission mains, foundation piling, structural columns, long runs | Piling and transmission lines where the specification calls for a straight seam |
| Length per piece | TODOstandard and maximum length in m | TODOstandard and maximum length in m |
| Testing at GBTL | Hydrostatic, weld, dimensional and mechanical checks on every batch | Hydrostatic, weld, dimensional and mechanical checks on every batch |
| Documents | Mill test certificate on request | Mill test certificate on request |
| Made in Bangladesh by | GBTL, the only SSAW spiral pipe manufacturer in the country | GBTL |
| Reference project | Padma Multipurpose Bridge piling | Padma Multipurpose Bridge piling |
| Indicative lead time | TODOweeks from order to first dispatch | TODOweeks from order to first dispatch |
How spiral and LSAW pipe are made
Spiral (SSAW) pipe starts as hot rolled steel coil. The strip is fed at an angle into a forming mill, rolled into a cylinder and welded along the helical seam, inside and outside, by submerged arc welding. Because the diameter is set by the strip width and the feed angle together, one coil width can make a range of diameters by changing the angle.
LSAW pipe starts as a steel plate cut to the length of the pipe. The plate is formed into a cylinder, the two edges meet in one straight seam, and that seam is welded inside and outside by submerged arc welding. Each diameter needs plate of the right width, so LSAW runs are planned per size.
Where spiral pipe is the better fit
Spiral pipe is efficient for large diameters and long runs. Water transmission mains, foundation piling and structural columns are the usual uses in Bangladesh. GBTL makes spiral pipe from 273 to 3,600 mm OD in 3.0 to 25.0 mm wall, which covers the trunk main and piling diameters most projects call for. GBTL is the only SSAW spiral pipe manufacturer in Bangladesh, so spiral pipe for a local project can be made and tested inside the country.
Length per piece: TODOconfirm standard and maximum spiral pipe length per piece in m.
Where LSAW pipe is the better fit
Engineers ask for a straight seam where they want one short seam per pipe that is simple to inspect on site, or where the design was drawn around plate based pipe. LSAW pipe answers that requirement. GBTL makes LSAW pipe from 300 to 2,500 mm OD in 3.0 to 17.0 mm wall.
In general practice LSAW is also associated with heavy wall pipe. At GBTL the spiral range reaches 25.0 mm wall and the LSAW range reaches 17.0 mm wall, so check the wall you need against both ranges before you fix the seam type. Both spiral and LSAW pipe from GBTL were used for foundation piling on the Padma Multipurpose Bridge.
Size ranges at GBTL
Spiral (SSAW): 273 to 3,600 mm OD, 3.0 to 25.0 mm wall. LSAW: 300 to 2,500 mm OD, 3.0 to 17.0 mm wall. Both are made at the GBTL plant at Sadipur, Mohojampur, Sonargaon, Narayanganj. The right wall for a given diameter depends on the duty: TODOtypical wall per OD for water mains and for piling.
Testing and documentation
Every spiral and LSAW batch goes through hydrostatic, weld, dimensional and mechanical checks at the mill. Mill test certificates are supplied on request. The plant runs under ISO 9001:2015 and BSTI. Steel grade, coating and lining follow the project specification and are confirmed at quote.
How to specify
Send GBTL Engineering the outside diameter, wall thickness, length per piece, total quantity in MT, the seam type if your specification fixes it, any coating or lining requirement and the delivery site. GBTL confirms the route, price and lead time on quote. Indicative lead time: TODOtypical lead time for spiral and LSAW orders in weeks.
Frequently asked questions
Is spiral pipe weaker than LSAW pipe?
Both are submerged arc welded inside and outside, and both are hydrostatically tested at GBTL. The seam pattern alone does not make one weaker. Which one your project accepts is set by the project specification, and both spiral and LSAW pipe from GBTL were used for piling on the Padma Multipurpose Bridge.
What diameters can GBTL make?
Spiral (SSAW) pipe from 273 to 3,600 mm OD with 3.0 to 25.0 mm wall, and LSAW pipe from 300 to 2,500 mm OD with 3.0 to 17.0 mm wall. Above 2,500 mm OD, spiral is the only route at GBTL.
Who makes SSAW spiral pipe in Bangladesh?
Gram Bangla Tubes Ltd (GBTL) is the only SSAW spiral pipe manufacturer in Bangladesh. The plant is at Sonargaon, Narayanganj, and the company has run since 2005.
Can GBTL supply coated or lined pipe?
Coatings and linings follow the project specification. State the requirement in your quote request and GBTL Engineering will confirm how it is met on quote.
What do I send to get a quote?
Outside diameter, wall, length per piece, quantity in MT, seam type if fixed, coating or lining requirement, delivery site and the project name. Call +88 01907 084 261 or email info@grambanglatube.com.