LSAW vs SSAW Steel Pipe: Key Differences and Applications

At a Glance

• LSAW and SSAW pipes serve large-diameter pipeline applications exceeding 24 inches, with LSAW dominating the high-pressure transmission segment
• LSAW pipes offer superior dimensional accuracy and weld quality, making them essential for oil and gas transmission
• SSAW pipes provide cost efficiency for low to medium-pressure applications and projects with flexible diameter requirements
• The global SSA/LSAW market is driven by oil and gas infrastructure development, with Asia-Pacific holding the largest market share at 45%

Overview

When projects require large-diameter steel pipes exceeding 24 inches, engineers typically select between Longitudinal Submerged Arc Welded (LSAW) and Spiral Submerged Arc Welded (SSAW) pipes. These two manufacturing processes produce pipes with distinct characteristics, cost profiles, and application suitability. Understanding their differences is crucial for pipeline project planning and procurement decisions.

The oil and gas sector accounts for approximately 32% of the total steel pipes market by 2035, according to ResearchNester, driving significant demand for both LSAW and SSAW products in pipeline infrastructure worldwide.

Manufacturing Processes Compared

LSAW Pipe Manufacturing

LSAW pipes are manufactured by bending steel plates into cylindrical shapes and welding the longitudinal seams using the submerged arc welding (SAW) process. The manufacturing workflow includes:

1. Plate Preparation: Heavy steel plates (typically 12-50mm thick) are inspected and edge-prepared through milling or grinding

2. Forming: Plates pass through UOE, JCOE, or RB (Roll Bending) forming lines to create C-shapes, U-shapes, or O-shapes

3. Inside Welding: The first SAW pass completes the inside longitudinal seam

4. Outside Welding: The second SAW pass completes the outside longitudinal seam

5. Expanding: Mechanical or hydraulic expansion improves roundness and relieves welding stresses

6. Testing: Comprehensive NDT including ultrasonic testing, radiographic testing, and hydrostatic testing

LSAW pipes typically range from 16 inches to 100 inches in diameter, with wall thicknesses from 6mm to 40mm.

SSAW Pipe Manufacturing

SSAW pipes are produced by helically winding steel strips at an oblique angle, creating a continuous spiral seam. The SSAW process involves:

1. Strip Preparation: Steel coils are slitted to required widths and inspected

2. Forming: Strip passes through consecutive forming rolls arranged helically

3. Welding: Inside and outside SAW passes complete the spiral weld

4. Cutting: Pipes are cut to specified lengths

5. Testing: Similar NDT protocols as LSAW, though weld complexity requires enhanced inspection

SSAW pipes range from 16 inches to 300 inches in diameter, offering superior flexibility for varied diameter requirements.

Key Differences Summary

Characteristic	LSAW Pipe	SSAW Pipe
Maximum Diameter	100 inches (2,540mm)	300 inches (7,620mm)
Weld Type	One longitudinal seam	Continuous helical seam
Dimensional Accuracy	Superior	Moderate
Wall Thickness Capability	Up to 40mm+	Up to 25mm
Production Efficiency	Lower	Higher
Cost Efficiency	Lower	Higher
Hydrostatic Performance	Superior	Good

Application Suitability

LSAW Pipe Applications

LSAW pipes are preferred for:

1. High-Pressure Oil and Gas Transmission: Critical long-distance pipelines requiring superior pressure containment

2. Subsea Pipeline Systems: Deepwater applications demanding enhanced mechanical properties

3. Sour Service Lines: Environments with hydrogen sulfide exposure requiring rigorous quality control

4. Onshore Transmission Mains: High-capacity pipelines spanning hundreds of kilometers

5. Critical Infrastructure: Projects with stringent safety and reliability requirements

LSAW pipes dominate the API 5L X70 and X80 high-grade pipeline market, where their superior weld quality and dimensional accuracy are essential.

SSAW Pipe Applications

SSAW pipes serve:

1. Low to Medium-Pressure Water Transmission: Municipal water distribution systems

2. Structural Piling: Foundation support for buildings and marine structures

3. Slurry Pipelines: Mining and mineral processing applications

4. Low-Pressure Oil Lines: Gathering systems and storage terminal connections

5. Flexible Diameter Projects: Applications where exact diameters may vary or require custom sizing

The SSAW process’s flexibility makes it particularly suitable for projects requiring non-standard diameters or those with variable flow capacity requirements.

Weld Quality and Structural Integrity

The structural implications of weld geometry are significant:

LSAW Weld Characteristics

• Single longitudinal seam: Easier to inspect and verify
• Accessible weld position: Optimal welding conditions achieved
• Lower residual stress: Controlled expansion process reduces stress concentrations
• Superior fracture toughness: Critical for high-pressure service

Industry standards including API 5L and ISO 3183 specify stringent requirements for LSAW weld quality, including mandatory ultrasonic testing and radiographic examination.

SSAW Weld Characteristics

• Continuous helical seam: More complex weld geometry
• Variable weld angle: Changes along pipe circumference
• Higher residual stress: Spiral welding introduces circumferential stress components
• Challenging NDT access: Internal weld inspection more difficult

For high-pressure applications, SSAW welds require enhanced inspection protocols including automatic ultrasonic testing (AUT) systems capable of detecting defects in the complex spiral geometry.

Cost Considerations

The cost differential between LSAW and SSAW reflects manufacturing efficiency and material utilization:

Factor	LSAW	SSAW
Raw Material Utilization	85-90%	95-98%
Manufacturing Complexity	Higher	Lower
Production Speed	Slower	Faster
Quality Control Costs	Higher	Moderate
Total Pipe Cost	Higher	10-20% lower

For large-diameter pipelines extending over 100 kilometers, the 10-20% cost savings from SSAW selection can translate to millions of dollars in project savings, provided application requirements permit.

Quality Standards and Testing

Both pipe types must comply with international standards:

API 5L Requirements

• PSL1 and PSL2 product specification levels define quality tiers
• Chemical composition and mechanical property requirements
• Mandatory testing including tensile, impact, and flattening tests
• Weld seam inspection protocols

ISO 10893 Standards

• Part 6: Radiographic testing of weld seams
• Part 8: Ultrasonic testing for laminar imperfections
• Part 11: Ultrasonic testing for longitudinal/transverse weld defects

Project-Specific Requirements

Critical pipeline projects often impose additional requirements:

• Stringent charpy impact testing at design temperature
• Fracture toughness testing using CTOD methodology
• Corrosion testing for sour service applications
• Third-party inspection during manufacturing

Conclusion: Making the Right Selection

The LSAW versus SSAW decision depends on several factors:

Select LSAW pipes when your project involves high-pressure transmission, critical service conditions, or stringent safety requirements. The superior weld quality, dimensional accuracy, and mechanical properties of LSAW pipes make them the industry standard for oil and gas transmission pipelines. At Createel International Limited, our LSAW manufacturing facilities produce API 5L grade pipes with comprehensive NDT verification.

Select SSAW pipes when your application involves low to medium pressures, flexible diameter requirements, or budget constraints. SSAW pipes deliver reliable performance for water transmission, structural piling, and non-critical industrial applications at significantly reduced costs.

For pipeline projects, always consult with engineering specialists and consider total lifecycle costs including installation, maintenance, and potential failure consequences. The initial cost savings from SSAW selection must be weighed against long-term reliability requirements.

LSAW and SSAW Pipe Supply from CREATEEL

We supply both LSAW (longitudinal submerged arc welded) and SSAW (spiral submerged arc welded) steel pipes for long-distance oil, gas, water, slurry, and structural/piling applications. Both processes use double-submerged arc welding (DSAW) for deep-penetration, high-integrity welds.

Parameter	LSAW (JCOE / UOE)	SSAW (Spiral / HSAW)
Forming Process	Steel plate pressed into U then O shape (JCOE/UOE), longitudinally welded ID+OD	Hot-rolled coil formed helically, spiral welded ID+OD
Diameter Range	16″ – 100″ (406 – 2540 mm)	16″ – 120″ (406 – 3050 mm), up to 300″ for piling
Wall Thickness	6 – 40 mm (up to 100 mm for heavy-wall)	5 – 25.4 mm
Lengths	6 m, 12 m, 18 m, up to 24 m on request	6 m, 12 m, 18 m (long lengths due to coil)
Standards	API 5L PSL1/PSL2, ISO 3183, EN 10217/10219, ASTM A252/A572/A671/A672, AS/NZS 1163, CSA Z245	API 5L PSL1/PSL2, ISO 3183, EN 10217/10219, ASTM A252/A139, AWWA C200
Grades	Gr.B, X42–X80, S235/S275/S355JR/J0/J2, P235/P265/P355	Gr.B, X42–X70, S235/S275/S355
Ends	Beveled for welding; plain ends on request	Beveled or plain ends
Coatings	FBE, 3PE/3PP, CWC (concrete weight coating), internal epoxy	FBE, 3PE, IPN8710 internal lining for water
Primary Applications	Long-distance oil/gas transmission, deep-water risers, high-pressure cross-country pipelines, structural columns	Water transmission, low-medium pressure oil/gas, piling, structural, slurry pipelines

Common Buyer Questions

Q: Can SSAW pipes be used for high-pressure natural gas transmission?

A: While technically possible, SSAW pipes are rarely specified for high-pressure transmission above 1,000 psi due to weld complexity and inspection challenges. LSAW or seamless pipes are preferred for such applications.

Q: What is the typical cost difference between LSAW and SSAW pipes?

A: SSAW pipes typically cost 10-20% less than comparable LSAW pipes, primarily due to higher material utilization and manufacturing efficiency.

Q: How do I verify weld quality for large-diameter pipes?

A: Request documentation of ultrasonic testing (UT), radiographic testing (RT), and hydrostatic testing per applicable standards. For critical applications, consider third-party inspection during manufacturing.

Q: What diameter ranges do LSAW and SSAW pipes cover?

A: LSAW pipes typically range from 16″ to 100″ (406mm to 2,540mm), while SSAW pipes can reach up to 300 inches (7,620mm) in diameter.