Different types of welded steel pipes: LSAW VS SSAW

Different types of welded steel pipes: LSAW VS SSAW

Welded steel pipes can be divided into many types according to the welding process and use, including straight seam submerged arc welded pipe (LSAW) and spiral submerged arc welded pipe (SSAW). Here are the main differences:

1. Welding method
From the perspective of welding methods, the welding methods of straight seam steel pipe and spiral steel pipe are the same, and the welding method of submerged arc welding is adopted. However, in the actual welding process, the straight steel pipe often has a large number of T-welds, in such welds, there are often some residual stresses, although this will not cause too much impact on the use, but it is the impact of these residual stresses, which increases the possibility of cracks in the steel pipe.

2. Molding process
LSAW (straight seam submerged arc welding pipe) : The steel plate is bent and formed and welded in a straight line weld. The weld is distributed along the length of the steel pipe.
Process: The steel plate is rolled into a cylinder, and then welded by double-sided submerged arc welding process.
Features: Fewer welds, high welding strength, suitable for large diameter and high pressure applications.

SSAW (spiral submerged arc welding pipe) : The steel strip is rolled into a cylinder at a certain Angle (usually a spiral Angle), and the weld is spiral distributed.
Process: The steel strip is rolled and welded with spiral Angle through the forming machine.
Features: Long weld, but high production efficiency, suitable for long-distance pipeline.

3. Structural characteristics and advantages

peculiarity	LSAW	SSAW
Weld distribution	Straight weld	Spiral weld
Number of welds	Few, usually 1-2	Many, spiral distribution, long weld
Dimensional accuracy	taller	Slightly inferior to LSAW
intensity	Fewer welds, uniform welding strength inside and outside	Long weld
cost	higher	Relatively low
Applicable pipe diameter	Usually used for large diameters	Can accommodate a larger diameter range

4. Application field

LSAW: Suitable for high demand projects, such as high pressure transportation, deep sea pipelines, bridge construction and high-rise buildings, especially suitable for large diameter, high pressure environment.
SSAW: Commonly used in low and medium pressure transportation, suitable for long distance transportation, such as water, oil, natural gas, etc., especially suitable for long distance transportation projects.