What is SSAW steel pipes?

In previous articles, we covered the difference between ERW and LSAW steel pipes. Now, let’s introduce another type: spiral submerged arc welded (SSAW) steel pipes.

SSAW steel pipes are manufactured by winding the pipe material at an angle to the centerline of the forming pipe, creating a spiral seam. This angle is adjustable, and the welding occurs simultaneously as the pipe is formed. The main advantage of SSAW pipes is their versatility; the same specifications can produce pipes with various diameters, and the range of compatible raw materials is broader. The spiral seam design also helps to distribute stress effectively, providing better stress resistance.

SSAW steel pipes

However, SSAW pipes have some disadvantages. The geometric shape tends to be less precise, and the weld seam is longer compared to straight seam pipes. This extended seam length increases the likelihood of defects such as cracks, porosity, slag inclusion, and weld misalignment. The welding stress in SSAW pipes is often in a tensile state, which may lead to more susceptibility to welding defects.

According to common design standards for long-distance oil and gas pipelines, SSAW pipes are typically suitable only for less critical areas . However, international advancements in technology have improved the production process of SSAW pipes. By using separated steel plates for forming and welding, combined with pre-welding, final welding, and post-weld cooling expansion, the weld seam quality of SSAW pipes now closely matches that of UOE pipes.