LSAW vs SSAW Pipe: Differences, Uses & How to Choose

The main difference between LSAW and SSAW pipe is the weld seam. LSAW steel pipe (longitudinal submerged arc welded pipe) is made from steel plate and has a straight seam parallel to the pipe axis. SSAW steel pipe (spiral submerged arc welded pipe, also called HSAW) is made from hot-rolled coil and has a spiral seam wrapped around the pipe. They are two separate types of SAW (submerged arc welded) pipe. This page compares the difference between LSAW and SSAW in manufacturing, weld length, size range and applications.

LSAW vs SSAW Pipe: What’s the Difference?

LSAW and SSAW pipes are both used for large-diameter pipelines and structural applications, but there are clear differences between the two.

1. Different Specifications

Both types are mainly used for large-diameter pipe. SSAW pipes can use strip of the same width to produce pipes with different diameters, and can also use narrower strip to produce larger diameters, by adjusting the forming angle. The size range of LSAW pipes is limited by plate size and forming equipment.

2. Different Manufacturing Processes and Weld Seams

LSAW (Longitudinal Submerged Arc Welded)
It is made by welding steel plates longitudinally, and generally uses UOE, JCOE and other forming processes, which include an expansion step used to size the pipe.

Weld seam: straight, along the axis of the pipe.

SSAW (Spiral Submerged Arc Welded)
The hot rolled coil is welded after forming at a spiral angle.
Weld seam: spiral, wrapped around the pipe at an oblique angle.

SSAW pipe is produced continuously from coil, while LSAW pipe is formed plate by plate.

3. Different Weld Length and Quality Control

LSAW: Shorter weld seam per length of pipe.

SSAW: Longer weld seam per length of pipe, so more weld length must be inspected and controlled.

Neither type is automatically stronger or safer. Strength and pressure rating depend on the steel grade, wall thickness, diameter, design code and product standard.

4. Different Application Ranges

LSAW: Commonly used for oil and gas transmission pipelines and structural support projects.

SSAW: Widely used for water pipelines, urban pipelines, piling, infrastructure and other large-diameter fluid transportation. It can also be used for oil and gas where the project specification permits.

How to Choose between LSAW and SSAW Pipe?

When selecting between LSAW pipe and SSAW pipe, it’s important to evaluate the project’s technical and economic requirements to ensure the most suitable type of welded pipe is used.

1. Operating pressure:

Start with the project specification and applicable standard, which may require a specific seam type.

2. Project budget:

Compare quotations on the same standard, grade, wall thickness and inspection scope. Price depends on size, steel cost and market conditions, not on pipe type alone.

3. Pipeline length and diameter:

SSAW pipes provide greater flexibility in diameter, while LSAW pipe size is limited by plate size and forming capacity. Confirm the manufacturer’s size range. For smaller diameters, ERW pipes are also commonly considered.

4. Dimensional acuracy:

Specify the required roundness, straightness and dimensional tolerance in the order, and confirm that the manufacturer can meet them.

With the continuous advancement of science and technology and the continuous changes in market demand, manufacturers of LSAW pipes and SSAW pipes should continue to increase investment in technological innovation and R&D to improve product quality and performance to adapt to market development trends.

FAQ (Frequently Asked Questions)

 

Q1: Is SSAW pipe a type of LSAW pipe?

A1: No. Both are SAW pipes, but LSAW has a straight longitudinal seam and is made from plate, while SSAW has a spiral seam and is made from coil.

 

Q2: Which has better pressure-bearing capacity, LSAW or SSAW?

A2: Neither is better by pipe type alone. It depends on steel grade, wall thickness, diameter and design code, so follow the project specification.

Q3: Can SSAW pipe be used for oil and gas pipelines?

A3: Line pipe standards such as API 5L include helical-seam SAW pipe, but whether it is accepted depends on the project or owner specification.

Read more: 

Difference between Spiral Steel Pipe and LSAW Steel Pipe

ERW Pipe vs LSAW Pipe: Key Differences, Cost, and Applications