LSAW Steel Pipe (Longitudinal Submerged Arc Welded)
LSAW pipe is produced by cold-forming a single steel plate into a ‘J’, ‘C’, or ‘O’ shape, then welding the longitudinal seam internally and externally using the submerged arc welding process.
Material
Carbon Steel and High-Strength Low-Alloy Steel. Common grades include API 5L PSL1/PSL2 (X42-X100), ASTM A671/A672 (pressure vessel grades), EN 10217-1 P235-P460, GB/T 9711 L245-L830.
Model
UOE Pipe, JCOE Pipe, SAWL Pipe
Size
Outer Diameter (OD) range: typically from 16 inches (406 mm) to 64 inches (1626 mm) and larger with special equipment.
Thickness
Wall thickness typically from 6 mm to 40 mm, with capabilities for even thicker walls for special applications.
Standard
API 5L, ASTM A671, ASTM A672, EN 10217-1, GB/T 9711, ISO 3183.
MOQ
10 Metric Tons (project-dependent).
Delivery Time
Standard lead time is 10 to 16 weeks from order confirmation, dependent on diameter, wall thickness, grade, and required testing/coating.
Long Description
LSAW (Longitudinal Submerged Arc Welded) steel pipe is manufactured from steel plates, which are first beveled on the edges and then formed into a cylindrical shape through various methods such as the UOE process (U-ing, O-ing, Expansion), JCOE (J-ing, C-ing, O-ing, Expansion), or roll bending. The key characteristic is its single, straight longitudinal weld seam. After forming, the seam is welded from the inside and outside using the submerged arc welding (SAW) technique, which produces deep penetration, high-quality welds with excellent mechanical properties. This manufacturing process allows for precise control over dimensions and wall thickness, making LSAW pipe suitable for high-pressure applications and large diameters where dimensional accuracy and weld integrity are critical. It is the preferred choice for major onshore and offshore oil and gas transmission pipelines, as well as for high-value structural projects.
Key Product Highlights
LSAW pipes feature a single, straight longitudinal weld seam, which is easier to inspect and offers predictable performance under hoop stress.
The UOE/JCOE forming process ensures excellent roundness, straightness, and dimensional consistency, especially in large diameters.
Capable of handling higher wall thicknesses compared to spiral weld pipes, making them suitable for high-pressure and deep-water applications.
The submerged arc welding process results in superior weld quality with high toughness and resistance to cracking.
Often supplied with beveled ends and precise length, optimized for automatic welding during pipeline construction.
Product Advantages
Superior mechanical properties, particularly in the weld heat-affected zone (HAZ), due to controlled welding and potential post-weld heat treatment.
Excellent dimensional tolerances on diameter, wall thickness, and length facilitate efficient pipeline laying and joining.
Comprehensive non-destructive testing (NDT), including ultrasonic and radiographic inspection, is standard to ensure weld integrity.
The production process is well-suited for applying internal and external anti-corrosion coatings in-line or at adjacent facilities.
Full traceability from plate to finished pipe, with extensive certification packages meeting the strictest project specifications.
Industry Application
This pipe is used for long-distance high-pressure oil and gas pipelines, offshore platform risers and conductors, subsea pipelines, piling for ports and bridges, structural columns in large buildings, and high-pressure penstocks.
Technical Specifications
| Parameter | Unit | High-Pressure Line Pipe (e.g., API 5L X65 PSL2) | Pressure Vessel Pipe (e.g., ASTM A671 CL70) | Offshore Structural Pipe (e.g., API 2H Gr.50) | Notes |
|---|---|---|---|---|---|
| Carbon Content (C) | % | ≤ 0.16 (Max, per Sour Service) | ≤ 0.30 | ≤ 0.22 | Strictly controlled, especially for PSL2 and low-temp service. |
| Manganese (Mn) | % | ≤ 1.60 | 0.50 – 1.35 | ≤ 1.60 | Alloying element critical for strength and toughness. |
| Phosphorus (P) | % | ≤ 0.025 | ≤ 0.035 | ≤ 0.030 | Very low limits for high-grade line pipe. |
| Sulfur (S) | % | ≤ 0.015 | ≤ 0.035 | ≤ 0.030 | Very low limits to prevent HIC/SSC in sour service. |
| Tensile Strength | MPa | 535 – 760 (X65) | ≥ 485 (CL70) | ≥ 455 | Strictly specified range for pipeline grades. |
| Yield Strength | MPa | 450 – 600 (X65) | ≥ 260 (CL70) | ≥ 345 | Minimum and maximum often specified (Rounded). |
| Elongation | % | See API 5L Table 8 | ≥ 20 | ≥ 22 | |
| Hardness | HV10 | ≤ 250 (Typical for Sour Service) | N/A | N/A | Hardness control is critical for sour service pipelines. |
| Outer Diameter (OD) | mm | 406 – 1626 | 406 – 1626 | 406 – 1626 | Core range for major pipeline projects. |
| Wall Thickness | mm | 6 – 40 | 6 – 40 | 10 – 40 | Thick-wall capability is a key feature. |
| Length | m | 10 – 12.2 (Standard), up to 18.3 | 6 – 12 | 6 – 18 | Length optimized for transport and field welding. |
| Surface Treatment | – | Bare, Beveled Ends (Protected) | Bare, Beveled/Plain Ends | Bare, Plain Ends | Typically bare for subsequent coating; bevels per welding specs. |
| Coating / Finish | – | Plain/Beveled End, Internally Coated | Plain/Beveled End | Plain End | Ends prepared for specific joining methods (welding, flange). |
| Welding Process | – | Longitudinal Submerged Arc Welding (SAWL) | Longitudinal Submerged Arc Welding (SAWL) | Longitudinal Submerged Arc Welding (SAWL) | Defines the product category and quality level. |
| Standard Example | – | API 5L PSL2 X65 SAWL, UOE | ASTM A671 CL70 CC Class 1 | API 2H Grade 50 | Representative high-demand specifications. |
Packaging & Surface Treatment
Pipes are handled with extreme care to prevent damage to the beveled ends and pipe body. They are often stored and shipped on wooden saddles or cradles, secured with heavy-duty straps or chains. Beveled ends are protected with durable plastic or steel caps. The pipe is typically supplied bare (with light mill scale) for external coating (e.g., FBE, 3LPE, concrete) and internal lining at a specialized coating plant, which is standard practice for major pipeline projects.
Aliases Names
SAWL Pipe, UOE Pipe, JCOE Pipe, Longitudinal Seam Welded Pipe, Plate Pipe, Heavy Wall Pipe.
