Different Between SAW and ERW Pipe?

What different between SAW and ERW pipe? There are many kinds of pipes in the carbon steel pipe. You will see the weld steel pipe and seamless steel pipe. And in the welded steel pipe, you will find different methods of forming processes, such as ERW, LSAW, SSAW. So first, let’s see what the differences between SAW pipes and ERW pipe are?

Compare SAW and ERW

In manufacturing processes, we can see SAW pipes (LSAW, SSAW) and ERW pipes are very different. Seeing it right from the formation and welding method.

SAW Welded Steel Pipe Manufacturing Process:

In a single seam SAW steel pipe, the wedding do with the help of the submerged arc welding process. In this method, a welding arc submerged in welding flux. A Continues solid filler wire fed from the outside. The pipe is welding two sides, first is inside, and then welding from the outside.

ERW Welded Steel Pipe Manufacturing Method:

Two electrodes usually made from copper used to apply pressure and current. The electrodes are disc-shaped and rotate as the material passes between them. This allows the electrodes to stay in constant contact. In which with the material to make long continuous welds.

And hence, the performance of both the pipes different in the following aspects. You will see the details in five aspects following:

First, Different Definition.

We see the differences between SSAW pipe and ERW pipe from the definition. SAW pipe means Submerged Arc Welded pipe. And from different weld seam, there are two saw pipes, including LSAW and SSAW. As the name suggests, SSAW has a spiral weld seam. And LSAW has a longitudinal weld seam. ERW pipe means Electric Resistance Welded pipe.

Second, Different Weld Seam Between SAW and ERW Pipe

The surface quality is very important for pipes. Though both SAW and ERW pipes all have a weld seam. But for weld seam of ERW pipe is flat.

ERW pipe weld seam

ERW pipe weld seam.

SAW weld seam

SSAW pipe weld seam.

LSAW weld seam

LSAW pipe weld seam.

And the weld seam of the SAW pipe is not flat.

You will see the weld seam of the LSAW pipe and SSAW pipe is higher than the steel plate. And the tolerance of weld seam height specified in specifications. If compare ERW pipes with SAW pipes, ERW pipes surface quality is better. ERW pipes are smooth and have a better finish. In most of the SAW pipes, it is about the weld reinforcement internal and external.

Third, the Defects Found in ERW Pipes Are Lesser Than SAW Pipes.

We will see it from the defects. As there is a solvent deposit in SAW. It results in more defects apart from the defects in the volume. The defects found in ERW pipes are only confined to wire-line and straight welds. it can inspected.

The defects can noticed. And the ultrasonic reflection on the surface makes it easier to detect. But for saw pipe, inspections are not only for weld seam but also for raw material. As the SAW pipes are all larger than 219 mm, and usually have thick wall thickness.

Forth, Residual Stress Ratio.

The residual stress ratio in ERW is lower than SAW pipes.

As ERW pipe deformation happens more in ERW followed by sizing of flat oval. It results in elliptical vertical changes and necking, thereby making the stress smaller.

The displacement of ERW pipes was smaller. It compares the axial and transverse incisions for comparison with SAW pipe built. When using the same material and it was also easy to detect.

Fifth, Performance.

Although the performance of both ERW and SAW pipe are the same. Once the pipes have a defect, the steel scrap and welding can do on ERW. while it is not the same in case of SAW, which would result in cracking or corrosion, making the ERW more durable.

From these five aspects we see differences between SAW and ERW. You already have some impression about SAW pipe and ERW pipe. Though we are professional LSAW pipe manufacturer, we learned ERW and SAW pipes as well.

If you have any other questions, or advices, please feel free to contact with us.