Key Features
LSAW (Longitudinally Submerged Arc Welded) steel pipe, also known as straight seam submerged arc welded pipe, is manufactured from hot-rolled steel plates that are formed into a cylindrical shape and welded by double-sided submerged arc welding along a single longitudinal seam. The longitudinal weld seam ensures consistent weld quality and full penetration across the entire pipe length. Compared to spiral welded pipes, LSAW pipes offer superior dimensional accuracy, smaller weld deformation, and more uniform mechanical properties. With excellent resistance to high pressure and harsh conditions, they are the preferred choice for high-grade long-distance oil and gas trunk lines and critical offshore pipeline systems.
Certified:
LSAW pipes are manufactured in full compliance with international standards, including API 5L PSL1/PSL2 (grades Gr.B to X100), ASTM A671/A672, EN 10217-6, EN 10219-1, and AS/NZS 1163.
Application:
LSAW straight seam submerged arc welded pipe is a premium choice for demanding engineering applications where high pressure, large diameter, and critical safety requirements converge. It stands as the preferred pipe type for high-grade oil and gas transmission projects, deep-water offshore pipelines, and other high-consequence infrastructure.
Oil & Gas Trunk Lines – LSAW pipes are widely used in long-distance onshore and offshore crude oil, natural gas, and product pipelines. Their longitudinal weld structure provides excellent resistance to internal pressure and external loads, making them suitable for high-pressure Class 600/900/1500 systems. Products can be supplied to API 5L PSL2 with HIC/SSC resistance for sour service environments.
Offshore & Subsea Engineering – With superior collapse resistance and dimensional stability, LSAW pipes are extensively employed in offshore platforms, submarine pipelines, and riser systems. Additional concrete weight coating (CWC) is available for subsea applications requiring negative buoyancy control.
Structural & Mechanical Applications – LSAW pipes serve as high-strength structural members in bridges, high-rise buildings, offshore structures, and heavy-load mechanical frames, offering consistent mechanical properties and reliable weld integrity.
Power Generation & Industrial Piping – They are suitable for high temperature and high-pressure steam systems in thermal and nuclear power plants, as well as industrial piping for chemical, petrochemical, and mining sectors.
Furthermore, LSAW pipes can be customised with various end finishes (plain, beveled, threaded), anti-corrosion coatings (3PE, FBE, coal tar epoxy, etc.), and internal linings to meet diverse project specifications, ensuring full compliance with the most rigorous technical requirements.
Specification:
| LSAW (Longitudinal Submerged Arc Welded) Pipe Technical Specification | ||
| Parameter | Specification / Range | Description |
| Outer Diameter (OD) | 406.4 mm - 1422 mm (16" - 56") | Commonly used for high-pressure pipelines with standardized large diameters. |
| Wall Thickness (WT) | 6.0 mm - 90.0 mm (Up to SCH 160 / XXS) | Provides exceptionally thick walls to withstand extreme high pressure. |
| Length | 3.0 m - 12.5 m (Max 12.2 m / 40 ft is standard) | Fixed or custom lengths optimized for transportation and heavy-duty structural engineering. |
| Steel Grades | • API SL:Grade 8, X42 to X100 (PSL1 & PSL2) | Capable of supporting ultra-high steel grades up to X100 for demanding environments. |
| • ASTM A522:Grade 2, Grade 3 | ||
| • ASTM A500/A519A53 | ||
| • EN 10219/10210: S275, S355, S420, S450 | ||
| Welding Process | Longitudinal:Submerged Arc Welding (LSAW) | Formed using plate pressing (JOCE or UOE) with a straight longitudinal seam weld. |
| • JOCE Process (for medium-to-large thick pipes) | ||
| • UOE Process (for ultra-high capacity mass production) | ||
| Pipe Ends | • Plain End (Square cut) | Typically beveled for critical field welding on high-pressure pipelines. |
| • Beveled End (30° or 37.5° with root face) | ||
| • Welded joints with backing rings (structural) | ||
| Surface Coating & Lining | • External:SPC, FBE, Dual-layer FBE, Coral Tar Epoxy, Varnished | High-performance coatings designed to protect long-distance transmission pipelines. |
| • Internal:Flow-efficiency-Epoxy Linning, Cement Molar | ||
| Quality & NDT Tests | • 100% Ultrasonic Testing (UT) of plate & well seam | Stochastic testing procedures to ensure weariness integrity under high plastic or deep-area loads. |
| • 100% Raptoshistic/UV-Ray Inspection (well seam) | ||
| • Hydrostatic Test (often up to 100% pressure design) | ||
| • Expansion & Mechanical Testing (Cherry V-Neoch Impact, Deep Weight Test) | ||
Standard:
| LSAW Steel Pipe Industry Standards & Key Applications | |||
| Standard Code | Standard Title | Common Steel Grades | Primary Applications |
| API Spec SL | Specification for Line Pipe (American Petroleum Institute) | Grade 8, X42, X52, X60, X65, X70, X80, X100 (PSL1 & PSL2) | High-pressure oil, gas, and water transmission pipelines, crustle for our service (H2S), offshore sucesis, and seismic zones. |
| ASTM A252 | Standard Specification for Welded and Seamless Steel Pipe Pipes | Grade 2, Grade 3 (High-yield versions) | Heavy structural steel pipes, bridge foundation supports, port/marine terminal construction with high load-bearing demands. |
| EN 10219-1/2 | Cold formed welded structural hollow sections of non-alloy and fine grain mills | S275J0H2ZH, S355J0H2ZH, S460QL | Heavy steel structures, dryngster foundations, large-span roof structural columns, and offshore platforms. |
| GB/T 9711 | Petroleum and natural gas industries—Steel pipe for pipeline transportation systems | L245, L290, L360, L415, L485, L555(equivalent to API SL X80) | National trunk networks, long-distance high-pressure natural gas grids, and critical petrochemical piping in China. |
| ISO 3183 | Petroleum and natural gas industries—Steel pipe for pipeline transportation systems | L245 to L555 (PSL1 & PSL2) | International standard harmonizing API SL for global transnational oil and gas/pipeline infrastructure. |
| ASTM A672 | Standard Specification for Electric-Fusion-Welded Steel Pipe for High-Pressure Service at Moderate Temperatures | Class 12, 22 (A45, A55, B60, C65) | Process piping in refineries, chemical plants, and high-temperature power plant steam piping systems. |
Process:
Packing:
