An LSAW pipe (“submerged arc welding”) is manufactured by cutting, bending, and welding steel plates (JCOE process). The two main types of LSAW pipes are the longitudinal (with a single or double straight seam weld, DSAW) and the spiral type (called, HSAW, SSAW or SAWL pipe).
Spiral steel pipes are mostly settled by measuring rulers, and the price of straight seam steel pipes is mostly settled by weighing, but the price of spiral steel pipe is about 300 yuan/ton cheaper than that of straight seam steel pipe.
LSAW (Longitudinal Submerged Arc Welded)
It is made by welding steel plates longitudinally, and generally uses UOE, JCOE and other forming processes.
Features: straight seam welding.
SSAW (Spiral Submerged Arc Welded)
The hot rolled coil is welded after forming at a spiral angle, and the weld is distributed in a spiral shape.
Features: Spiral weld.
LSAW: Straight weld, along the axis of the pipe.
SSAW: Spiral weld, wrapped around the pipe at an oblique angle.
LSAW: Short weld, easy for flaw detection, more stable and reliable quality;
Suitable for high pressure, large diameter, key structure projects.
SSAW: Long welds with more potential weld defects;
Slightly lower strength than LSAW, but cheaper to manufacture.
LSAW: Commonly used in high-demand situations such as long-distance high-pressure oil and gas transportation and structural support projects.
SSAW: Widely used in low-pressure fluid transportation, urban pipelines, infrastructure, etc.
In terms of market prospects, LSAW pipes are expected to see greater development space in high-end demand areas as the energy transmission and construction industries develop; SSAW pipes will consolidate their position in the medium and low pressure large diameter transportation market through technological upgrades and seek broader application areas. The two are not substitutes for each other, but complement each other, jointly meeting the diverse needs of industrial production and infrastructure construction.
Advantages
1. Excellent pressure resistance and structural stability, making it ideal for high-pressure oil and gas transportation.
2. Short, straight welds that are easy to inspect, resulting in higher reliability and fewer defects.
3. Outstanding dimensional accuracy, roundness, and straightness, which simplify on-site installation and welding.
4. Good low-temperature and fatigue resistance, allowing it to perform well in harsh working environments.
5. Stable and consistent quality, suitable for key engineering projects and large-diameter high-end applications.
Disadvantages
1. Higher production costs and market price compared with SSAW pipes.
2. Limited by steel plate dimensions, so it is less flexible for producing extra-large diameters.
3. More complex manufacturing process, leading to lower efficiency than SSAW continuous production.
Advantages
1. Lower production cost and more competitive price than LSAW pipes.
2. High production flexibility: can produce a wide range of large-diameter pipes using narrow steel strips.
3. Continuous coil-based production with high efficiency and low material waste.
4. Well-suited for large-diameter, medium- and low-pressure pipelines such as water supply and urban utility lines.
5. Longer spiral welds help distribute stress, providing certain strength benefits under some working conditions.
Disadvantages
1. Long spiral welds increase the chance of potential defects and make inspection more difficult.
2. Lower dimensional accuracy than LSAW pipes, with relatively poorer roundness and straightness.
3. Not the best choice for high-pressure, high-safety long-distance oil and gas pipelines.
4. Weld areas are prone to stress concentration and require stricter anti-corrosion treatment.
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:
For high-pressure oil and gas pipelines, LSAW pipes are preferred due to their straight welded seam, excellent mechanical strength, and superior reliability under extreme service conditions. Compared with ERW pipes, which are typically used for smaller diameters and moderate pressures, LSAW welded pipes can withstand higher internal stresses and provide longer service life.
2. Project budget:
If cost efficiency is a major concern, SSAW pipes offer a more economical choice. Their spiral welding process allows continuous production from steel coils, reducing material loss and manufacturing costs. They are well suited for low-pressure or non-critical systems such as water transmission and structural applications.
3. Pipeline length and diameter:
SSAW pipes provide greater flexibility in diameter and length, as the forming angle can be adjusted to produce large-diameter welded pipes continuously. This makes them practical for long-distance projects where fewer joints and faster installation are required.
4. Dimensional acuracy:
LSAW pipes deliver better roundness, straightness, and dimensional tolerance compared with SSAW or ERW pipe. This precision ensures a tight fit and easier alignment during field welding, which is essential in projects that demand high construction quality.
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.
Q1: What are LSAW and SSAW pipes?
A1: They are two variants of SAW (submerged arc welded) pipes, differing mainly in welding method—LSAW is longitudinal weld, SSAW is spiral weld.
Q2: What’s the main difference in their manufacturing processes?
A2: LSAW uses steel plates welded longitudinally (UOE/JCOE process); SSAW uses hot rolled coils formed at a spiral angle and welded.
Q3: Which has better pressure-bearing capacity, LSAW or SSAW?
A3: LSAW has better strength and reliability, suitable for high-pressure projects; SSAW has slightly lower strength but is more cost-effective.
Q4: How to choose between LSAW and SSAW?
A4: Choose LSAW for high-pressure, high-precision, key projects; choose SSAW for low-pressure, cost-sensitive, large-diameter low-demand projects.
Q5: What are their main application ranges?
A5: LSAW is for long-distance high-pressure oil/gas transportation; SSAW is for low-pressure fluid, urban pipelines and infrastructure.
Read more: Difference between Spiral Steel Pipe and LSAW Steel Pipe
