SAW vs SSAW vs LSAW: Submerged Arc Welding Techniques for Large Diameter Pipes

Introduction to SAW Pipe Manufacturing

Submerged Arc Welding (SAW) is the primary manufacturing method for large-diameter steel pipes. The three main variants—SAW (single), SSAW (Spiral SAW), and LSAW (Longitudinal SAW)—each have distinct characteristics suited for different applications.

Welding Process Comparison

SAW (Single Submerged Arc Welding)

Basic submerged arc process using one electrode:

Parameter	Typical Range	Comments
Current	400-1,200 A	DC or AC
Voltage	25-45 V	Adjusted for wire diameter
Wire Diameter	2.0-6.0 mm	Multiple wires possible
Travel Speed	0.3-1.5 m/min	Depending on current
Flux Type	Fused or bonded	Active or neutral

SAWW vs SSAW vs LSAW Comparison

Aspect	LSAW	SSAW
Manufacturing Process
Weld Orientation	Longitudinal (along pipe axis)	Helical/Spiral (at angle)
Forming Method	U/O/E forming presses	Three-roll benders
Number of Welds	1-2 longitudinal seams	1 continuous spiral seam
Weld Position	At 0° and 180° (optional)	Continuous around pipe

Weld Seam Positioning

Type	Weld Position	Weld Bead Count	Internal/External
LSAW (Single)	One longitudinal seam	2-4 passes	Both sides
LSAW (Double)	Two longitudinal seams	2-4 passes each	Both sides
SSAW	Spiral seam	2-4 passes	Both sides

Size Range Comparison

Parameter	LSAW	SSAW
Diameter Range
Typical	406 – 2,134 mm (16″ – 84″)	508 – 3,000 mm (20″ – 118″)
Maximum	6,000 mm	4,000 mm
Wall Thickness
Typical	6.0 – 50 mm	4.0 – 25 mm
Maximum	80 mm	40 mm
Length
Standard	6-12.2 meters	6-12.2 meters

Production Efficiency

Aspect	LSAW	SSAW
Manufacturing Speed
Welding Speed	1.0-3.0 m/min per head	0.5-2.0 m/min
Line Speed (typical)	0.5-2.0 m/min	0.3-1.5 m/min
Material Utilization
Plate/Coil Width	Must match pipe circumference	Flexible (can vary spiral angle)
Yield Rate	88-92%	85-90%
Equipment
Forming Equipment	Heavy presses (U/O/E)	Three-roll benders
Welding Stations	1-4 internal/external	1-2 spiral

Quality Characteristics

Quality Aspect	LSAW	SSAW
Weld Seam Quality	Excellent (straight seam, easy inspection)	Good (continuous, uniform properties)
HAZ (Heat Affected Zone)	Wide due to heavy wall	Narrower due to lower heat input
Residual Stress	Higher in longitudinal direction	More evenly distributed
Buckling Resistance	Better for collapse resistance	Good for external pressure
Roundness Control	Excellent	Good (requires control)

Application Scenarios

LSAW Pipe Applications

• Long-distance oil and gas transmission
• Offshore pipeline platforms
• Deepwater pipelines
• High-pressure transmission lines
• Subsea pipelines
• Cross-country pipelines
• Petrochemical plants

SSAW Pipe Applications

• Water transmission pipelines
• Sewer and drainage systems
• Offshore jacket platforms
• Structural pipe piles
• Low to medium pressure applications
• Large diameter water intake lines
• Marine dolphin structures

Selection Guidelines

Choose LSAW when:

• Very high pressure transmission
• Deepwater or subsea applications
• Thick walls required (above 25mm)
• Maximum diameter control needed
• API 5L PSL2 specifications
• Critical service conditions

Choose SSAW when:

• Water and low-pressure applications
• Large diameter for cost efficiency
• Moderate pressure requirements
• Structural applications
• Flexibility in coil/plate width
• Standard service conditions

Cost Analysis

Factor	LSAW	SSAW
Equipment Investment	Very high (heavy presses)	Moderate (three-roll)
Plate/Coil Cost	Higher (width specific)	Lower (flexible width)
Welding Consumables	Higher (multi-pass)	Standard
Labor Cost	Higher	Lower
Production Speed	Moderate	Moderate
Quality Assurance	Intensive	Standard
Overall Cost	Higher	Baseline to 10% lower

SAW Pipe Supply — LSAW and SSAW at CREATEEL

Both our LSAW and SSAW lines use double-submerged arc welding (DSAW) with internal and external passes, 100% radiographic or ultrasonic weld inspection, and full hydrostatic testing.

Parameter	LSAW (JCOE/UOE)	SSAW (Spiral)
Raw Material	Heavy steel plate (single-width)	Hot-rolled coil (continuous)
Diameter	16″–100″ (406–2540 mm)	16″–120″ (406–3050 mm)
Wall Thickness	6–40 mm (heavy-wall to 100 mm)	5–25.4 mm
Weld Geometry	Straight longitudinal seam, ID+OD passes	Helical seam, ID+OD passes
Standards	API 5L PSL1/PSL2, ISO 3183, EN 10217/10219, ASTM A252/A671/A672, AS/NZS 1163	API 5L PSL1/PSL2, ISO 3183, EN 10217/10219, ASTM A252/A139, AWWA C200
Grades	Gr.B–X80; S235–S355; P235–P355	Gr.B–X70; S235–S355
NDT	100% UT or RT of weld, plus UT of plate edges (PSL2)	100% UT or RT of weld per standard
Best For	High-pressure oil/gas transmission, offshore risers, structural columns	Water transmission, piling, low-mid pressure pipelines, slurry lines

Buyer FAQ

Q1: Which type is better for offshore pipelines?

A: LSAW is preferred for deepwater and subsea pipelines due to thicker walls, better collapse resistance, and superior weld quality for high-pressure service.

Q2: What is the maximum wall thickness for each type?

A: LSAW can achieve up to 80mm wall thickness, while SSAW is typically limited to 25-40mm depending on diameter.

Q3: Does spiral weld affect pipe strength?

A: Properly made SSAW pipe meets the same tensile and yield requirements as LSAW. The spiral weld is oriented at an angle to distribute stress more evenly around the pipe circumference.

Q4: What NDT methods are required for SAW pipes?

A: Typical NDT includes ultrasonic testing (UT) of weld seam, radiographic testing (RT) for weld quality, hydrostatic testing, and electromagnetic testing as specified.

Q5: Can SSAW pipe be used for sour service?

A: Yes, SSAW pipe can be manufactured to PSL2 specifications including sour service requirements, though LSAW is more commonly specified for severe sour service applications.