LSAW Carbon Steel Pipe — Factory Direct Supplier | Huaxia-Steel

Longitudinal Submerged Arc Welded (LSAW) carbon steel pipe is the industry answer when large diameters, heavy walls, and high pressure converge — oil and gas transmission lines, offshore piles, hydro schemes, and structural caissons. Formed from single steel plate and welded along one longitudinal seam under flux, LSAW delivers the wall uniformity and toughness that spiral (SSAW) and ERW routes cannot reach at these sizes. Huaxia-Steel supplies LSAW pipe from OD 406 mm (16″) to 1422 mm (56″), wall thickness 6.4–60 mm, to API 5L, ASTM A671/A672, and EN 10217, with full EN 10204 3.1/3.2 certification and third-party inspection welcome.

Product Overview

Forming routes: JCOE (progressive J-C-O forming + expansion) for flexible sizing and heavy walls; UOE for high-volume standardized line pipe; both produce a single longitudinal SAW seam, ID and OD welded.

Size range: OD 406–1422 mm; wall 6.4–60 mm; lengths up to 12.2 m (longer by arrangement up to 18 m for pile work).

Grade range: API 5L PSL1/PSL2 Gr. B through X80; ASTM A671 CC60/CC65/CC70, A672 B60–C75; EN 10217-3/10216 P235–P460; structural to EN 10225 S355 for offshore.

Weld testing: 100% radiographic or automated UT of weld seam, 100% UT of plate body, hydrostatic test per standard.

End finish: plain, beveled to API 5L / ASME B16.25, or flanged; specialty ends machined.

Specification Table

Parameter	Range / Value
Outside diameter	406 mm (16″) – 1422 mm (56″)
Wall thickness	6.4 mm – 60 mm
Length	6–12.2 m standard; fixed lengths to ±50 mm on request
OD tolerance	±0.5% (pipe body, D > 508 mm per API 5L); ±1% smaller sizes
Wall tolerance	±8% (weld zone), ±10% (pipe body) — tighter on request
Out-of-roundness	≤ 1.0% D standard; ≤ 0.5% D for expanded pipe ends (PSL2)
Unit weight (theoretical)	W = 0.02466 × t × (D − t) kg/m (t, D in mm)
Standard lengths & ends	Plain end / bevel 30° +2°, root face 1.6 ± 0.8 mm

Available Grades

Standard	Grades	Typical Use
API 5L PSL1 / PSL2	Gr. B, X42, X46, X52, X56, X60, X65, X70, X80	Gas & oil transmission, distribution
ASTM A671 / A672	CC60, CC65, CC70 / B60, B70, C75	Pressure piping at moderate/low temperature
EN 10217-3 / 10216-3	P235GH, P265GH, P355NH	European pressure pipework
EN 10225	S355G8+M / G10+M	Offshore structural piles and braces
ASTM A252	Gr. 2, Gr. 3	Piling, casings

Manufacturing Standards and Process Control

Plate enters the line with UT-laminar-inspection to ASTM A435 or EN 10160 S2/E2. After JCOE forming, the longitudinal SAW weld runs double-sided (inside + outside passes), then the pipe is either cold-expanded (typ. 0.3–0.8% OD expansion, which straightens, roundifies, and relieves residual stress) or mechanically calipered. PSL2 requires CVN impact testing at the specified design temperature on weld, HAZ, and body, plus hardness max 248–280 HV10 in the weld area depending on grade. Every lot carries heat-number traceability from plate to finished pipe — stenciled and encoded in the MTC.

Applications

Onshore and offshore oil & gas transmission pipelines (PSL2 X52–X80)

Water transmission and hydro penstocks (up to 60 mm wall)

Offshore monopile and jacket piles (EN 10225, API RP 2A welding)

Structural caissons, bridge piles, port engineering

High-pressure plant piping spools and suction/discharge headers

Quality Assurance

100% RT or AUT of longitudinal weld; 100% UT of body plate

Hydrostatic test to 1.5 × design pressure (PSL2: per API 5L tables), 10 s hold

CVN impact tests: body, weld, HAZ at stated temperature (PSL2)

Weld seam UT+RT re-inspection at pipe ends, cut-backs per lot

Dimensional survey: OD, ovality, wall (automated ultrasonic wall profiler), straightness ≤ 0.15% L

EN 10204 3.1 standard; 3.2 (Lloyd’s, DNV, SGS, BV witness) on request

Packaging and Shipping

Pipe is bundled in seaworthy steel-strapped bundles (loose pipe above 20″ OD is shipped loose), with plastic end caps or bevel protectors, external black paint or FBE/3LPE coating available from partner coaters. Marking per API 5L Annex: manufacturer, grade, size, heat number, standard, PSL level stenciled at each end. Containerization possible up to 24″ OD; larger diameters ship break-bulk with lashing plans. Documents: invoice, packing list, MTC, certificate of origin, RT/UT reports — issued in English before shipment for review.