LSAW Pipe Carbon Steel Longitudinal Submerged Arc Welded — Factory Direct Supplier | Huaxia-Steel

LSAW pipe (longitudinal submerged arc welded pipe) is the large-diameter carbon steel pipe made by forming steel plate into a cylinder along its length and welding the seam with a continuous submerged-arc process. The result is a pipe with a single straight weld, tight dimensional tolerance, and consistent mechanical properties suited to oil and gas transmission, structural piling, and pressure service. Huaxia-Steel supplies LSAW pipe from leading Chinese mills to API 5L, ASTM A671, ASTM A672, and EN 10219 standards.

Product Overview

LSAW pipe begins as hot-rolled steel plate or coil that is cut to width, formed into a U-shape by cold forming or press braking, then into an O-shape by a subsequent forming pass. The two edges are joined by submerged-arc welding (SAW) inside and outside to produce a fully penetrated longitudinal seam. The pipe is then expanded to final diameter and stress-relieved or normalized to refine the microstructure. Diameters range from 16 inches (406 mm) up to 60 inches (1524 mm) for line pipe and to 100 inches (2540 mm) and beyond for structural piling.

Specifications

Item	Details
Type	Longitudinal Submerged Arc Welded (LSAW) pipe
Outside diameter	406 mm – 1524 mm (16 in – 60 in); structural piling to 2540 mm (100 in)
Wall thickness	6 mm – 50 mm (heavier on request)
Length	Single random 6-12 m, double random 12-18 m, or cut-to-length
Welding process	Double-sided submerged-arc welding (DSAW); also single-side SAW for thinner walls
Delivery condition	As-welded, normalized, quenched and tempered, stress-relieved
Standard lengths	12 m fixed, 18 m fixed, or cut to project specification
Tolerance	API 5L or EN 10219, depending on order standard

Available Grades and Standards

API 5L PSL1 / PSL2: Grades A, B, X42, X46, X52, X56, X60, X65, X70, X80 – the workhorse grades for oil and gas pipelines.
ASTM A671: EFW pipe for atmospheric and lower-temperature service, classes CC55, CC60, CC65, CC70.
ASTM A672: EFW pipe for moderate-temperature pressure service, classes C55, C60, C65, C70.
EN 10219: Cold-formed welded structural sections, grades S235, S275, S355, S420, S460.
EN 10210: Hot-finished hollow sections for structural use, similar grades.
GB/T 3091: Chinese standard for welded steel pipe for low-pressure liquid delivery.
GB/T 9711: Chinese standard equivalent to API 5L for pipeline transmission.

Manufacturing Standards

API Spec 5L (line pipe specification) – most common for oil and gas transmission.
ASTM A671/A672 (electric-fusion-welded steel pipe for pressure service).
ASTM A139 (electric-fusion-welded medium-grade pipe).
EN 10219-1/2 (cold-formed welded structural hollow sections).
EN 10210-1/2 (hot-finished welded structural hollow sections).
ASME B31.4 / B31.8 (liquid and gas pipeline code).
DNV-OS-F101 (offshore submarine pipelines).

Applications

Long-distance oil and gas trunklines, especially large-diameter gas pipelines.
Offshore platform pilings and jacket leg sections.
Port and marine structural piling (submerged or driven).
Power plant water intake and discharge piping.
Penstocks for hydropower stations.
Large-bore process piping headers at refineries and chemical plants.
Pipe pile foundations for bridges, high-rise buildings, and offshore wind monopiles.
Wind tower cans (sections of large-diameter pipe that are rolled and welded).

LSAW vs SSAW vs ERW

Attribute	ERW	SSAW (HSAW)	LSAW
Typical diameter	60-660 mm	219-2540 mm	406-1524 mm
Weld direction	Longitudinal, high-frequency induction	Helical (spiral), submerged arc	Straight longitudinal, submerged arc
Wall accuracy	Tight	Moderate	Tight
Pressure rating	Up to X60 typically	Up to X65 typically	Up to X80 typically
Best for	Small-diameter line pipe and structural	Large-diameter piling and low-pressure fluid	High-pressure transmission, structural piling
Surface finish	Smooth	Helical weld bead visible	Two straight weld beads visible

Quality Assurance

Every LSAW pipe shipment from Huaxia-Steel is supplied with the following baseline documentation:

Mill test certificate per EN 10204 3.1 traceable to the plate heat number and the pipe serial.
Hydrostatic test at the required pressure (commonly 1.5 times design pressure for line pipe).
100% ultrasonic or radiographic inspection of the longitudinal weld seam.
Dimensional check for OD, wall thickness, length, straightness, and ovality.
Visual and surface inspection for plate defects, dents, and weld appearance.
Charpy impact testing at the specified temperature per PSL2 or per project specification.
Supplementary tests on request: drop-weight tear test (DWTT), hardness survey, HIC testing, strain-aged test, sour-service per NACE MR0175.

EN 10204 3.2 certification by SGS, BV, TUV, or DNV is arranged on request for export orders. Mill audits and witness inspections are standard for major pipeline projects.

Packing and Shipping

Standard export packing for LSAW pipe uses hexagonal bundles with steel strapping, end caps, and internal VCI oil. For large-diameter pipe piling, individual shipping with timber frames and lifting lugs is standard. Each pipe is marked with grade, OD, wall, length, heat number, and standards reference per API 5L or ASTM A671/A672. Shipping from Tianjin, Shanghai, and Qingdao in 20 ft, 40 ft, or flat-rack containers; break-bulk and bulk carriers for piling orders.

Why Buy LSAW Pipe from Huaxia-Steel?

Mill-direct pricing on API 5L, ASTM, and EN standards
Full diameter range from 16 to 60 inches for line pipe, piling to 100 inches
PSL2-ready with sour-service HIC testing and NACE compliance
Coordinated third-party inspection by SGS, BV, TUV, DNV, or Lloyds
Double-sided SAW with 100% NDT for code-stamped projects
Consolidated shipment with structural sections and plate to reduce freight

Need LSAW pipe for a pipeline, structural, or piling project? Send the diameter, wall thickness, length, grade, standard, and quantity. Our team will deliver a detailed proposal within two working days, including heat-treatment, NDT scope, and third-party inspection options.