Carbon Steel Welded Pipes Categories Explained: LSAW/DSAW/SSAW/ERW/EFW/CDW

Today at Trio Steel we will explain the difference between various welded pipes. Carbon Steel Pipes like API 5L Pipes, ASTM A671 Pipes, ASTM A672 Pipes, ASTM A691 Pipes generally come in LSAW/DSAW/SSAW/HSAW/CDW/ERW/EFW Categories
The categories are as below:
1) LSAW – Longitudinal Submerged Arc Welding : LSAW (Longitudinal Submerge arc welding steel pipe is a type of SAW pipe made of steel plates that were hot rolled by JCOE or UOE forming technology. JCOE technology represents the shaping and forming processes involved during manufacturing as well as the inner and outer welding and cold expansion carried out after welding. Similarly UOE Method starts with crimping the edges of a plate to form a U shape, followed by U-pressing and O-pressing to form a J shape. The final step is expanding the J-shaped pipe to form the finished product. LSAW pipes are produced by molding steel sheets to a cylinder and joining the ends together by welding in a straight line.

2) DSAW – Double Submerged Arc Welding – DSAW Pipe is similar to LSAW Pipe. The only difference being the Pipes have double welding i.e. on the outside and well as inside. This is generally done for higher OD greater than 36’’. Both inside and outside welds are required and are usually accomplished in separate processes, hence the word “double.”

3) SSAW/HSAW– Spiral Submerged Arc Welding/Helical Submerged Arc Welding – SSAW pipe takes form by rolling and welding a steel strip in a way that the pivotal direction is oblique to the axis or pipe center, making the weld seam in a spiral line. If the welding is done in Spiral Direction, it is called SSAW and it the direction is Helical then it is called HSAW. Spiral Welded Pipes take less time to manufacture and are cheaper compared to LSAW Pipes but it is the least preffered options due to the low weld quality. They are used for non-critical applications like water transport. A typical application for spiral welded pipe would be for power station cooling water systems (non-toxic, high volume, low pressure). For systems operating with very high volumes and low pressures, a spiral welded pipe may be used.

4) CDW – Cold Drawn Welding – CDW pipes are produced by expelling the metal to the required length and hence are superior and more expensive to ERW Pipes

5) ERW – Electric Resistance Welding – Electric resistance welded (ERW) pipes are longitudinally welded from metal after moving it afterward

6) EFW – Electric Fusion Welding – EFW steel pipe (Electric Fusion Welding) refers to an electron beam welding, the use of high-speed movement of the electron beam directed impact kinetic energy is converted to heat the workpiece so that the workpiece leaving the melt, the formation of the weld. EFW steel pipe is formed by rolling plate and welding the seam. The weld flash can be removed from the outside or inside surfaces using a scarfing blade. The weld zone can also be heat treated to make the seam less visible.

We at Trio Steel Supply all the above welded pipe categories, We generally prefer to offer LSAW Pipes and EFW Pipes to our customers due to their high quality and reliability of the weld. We generally cater to clients in critical sectors like oil & gas, defence, marine offshore etc.
The various pipes we offer are:
API 5L LSAW Pipes
API 5L DSAW Pipes
API 5L Seamless Pipes
ASTM A671 EFW Pipes
ASTM A672 EFW Pipes
And many more options.
Please feel free to contact us to understand the differences in more detail and for pricing and size availability.