API 5L Large Diameter SAWH & ERW Steel Pipes | SEW Structural & Fluid Tubes

Submerged Arc Welded Helical pipe(SAWH) is manufactured from hot-rolled steel coils formed into a continuous spiral and welded using the submerged arc welding (SAW) process on both internal and external seams. This production method ensures high weld integrity, uniform mechanical properties, and excellent performance under demanding service conditions.

1. Oil & Gas Transmission Pipelines

SSAW steel pipes are widely used in onshore oil and gas transmission projects, particularly for large-diameter and long-distance pipelines.

Key Performance Benefits

High resistance to internal pressure and cyclic loading

Excellent weld toughness and fatigue resistance

Stable mechanical properties along the full pipe length

Suitable for buried and above-ground pipeline systems

Applicable Standards & Grades

Standards: API 5L, ISO 3183

Steel Grades: API 5L Gr. B, X42, X52, X56, X60, X65, X70

Inspection: UT, RT, hydrostatic test, dimensional inspection

Coating Options

External: 3LPE / 3LPP / FBE

Internal: Epoxy or flow-enhancing lining (optional)

2. Water Transmission & Distribution Pipelines

For potable water, raw water, and wastewater transportation, SSAW pipes provide reliable hydraulic performance and long service life.

Key Performance Benefits Large diameter availability for high-flow systems Smooth internal surface for reduced pressure loss High corrosion resistance with appropriate coatings Long-term durability in underground installations

Applicable Standards & Grades Standards: ASTM A139, EN 10219, GB/T 9711

Steel Grades: Carbon steel structural grades as specified

Quality Control: Hydrostatic pressure testing and coating inspection

 Coating & Lining External: Coal tar epoxy, 3LPE, or epoxy paint Internal: Cement mortar lining, epoxy lining (as required)

3. Piling & Foundation Engineering

SSAW steel pipes are extensively used for driven piles, bored piles, and marine foundation structures due to their excellent load-bearing capacity.

Key Performance Benefits

High axial and lateral load capacity Excellent resistance to bending and impact during driving Cost-effective solution for large-diameter piles Suitable for marine, bridge, port, and offshore foundations

Applicable Standards & Grades

Standards: ASTM A252, EN 10219, JIS, GB standards

Steel Grades: Gr. 1 / Gr. 2 / Gr. 3 or equivalent

Optional Processing: Cutting, beveling, end-plate welding

General Technical Specifications

Outer Diameter (OD): 219 mm – 3,820 mm (customizable)

Wall Thickness:5.6mm-28mm Project-specific Length: Fixed or random lengths available Ends: Plain, beveled, or customized Quality Assurance & Certification Fully compliant with international standards Mill Test Certificates (EN 10204 3.1) supplied Third-party inspection (SGS, BV, TUV, etc.) available upon request Complete traceability from raw material to finished product.

                          Hot Stretch-reducing Electric Welding(SEW) pipes

SEW (Hot Stretch-reducing Electric Welding, High Frequency Welding Hot Tension Reduction) casing and tubing, adopting the combination of "High Frequency Straight SeamWelded Pipe & Pipe Hot Tension Reducing & Whole Pipe Body Heat Treatment" technology, is an advanced casing and tubing manufacturing process widely used in Europe andthe United States at present. The strength and size of SEW casing pipe are better than seamless pipe of the same steel grade and specification, and the resistance to extrusion ishigher than that of seamless pipe of the same specification.

Production Scope and Capacity

Production Equipment

SEW pipe production line has a set of coil longitudinal shear unit, a set of HFW unit, a set of hot tensile reduction unit and a set of pre-finishing unit, which are mainly used for pipemaking in the United States ABBEY, hot tensile reduction machine Germany KOCKS, hydraulic testing machine United States (BRONX), pipe processing Belgium (PMC-COLINET),non-destructive testing United States (TUBOSCOPE), hoop turning machine Germany.

                            Eco-Friendly Electric Resistance Welded (ERW) Pipeline & Energy Projects

Product Application

Electric resistance welded(ERW) pipes are mainly used for high-pressue transmission of petroleum,natural gas,refined oil and mineral slurry. We can provide various kinds of steel pipes for different purposes for the industries of machinery, chemical industry,construction,metallurgy,mining,etc. ERW steel pipe take the lead of filling the blank of ERW welded steel pipe in China.

Production Scope and Capacity

Production process

ERW pipe is manufactured by cold forming a flat steel strip into a rounded tube and passing it through a series of forming rollers to obtain a longitudinal seam. The two edges are then simultaneously heated with a high frequency current and squeezed together to produce a bond. The longitudinal ERW seam does not require filler metal while impurities in the heat affected zone are extruded during the welding process

UNCOILING & FLATTENING

Incoming coils are peeled and unwrapped for presentation into the flattener rolls. Flattening removes the coil set to produce a flat steel strip.

COIL JOINING

Coil ends are joined together with a butt weld to produce a continuous strip.

EDGE TRIMMING

Slitter blades and edge milling trims strip edges to provide the precise strip width required during the forming and ERW seam welding process.

FORMING

The forming process begins at the Breakdown Pass where the material is gradually bent from a flat steel strip into a rounded tube for presentation to the ERW seam welder.

WELDING

A high frequency electrical current flows through contact tips into the strip edges to produce the heat required for bonding the strip edges together as the material passes through the weld roll stand.

QUALITY CONTROL

Once the welding is complete, the finished pipe is visually inspected by Quality Control (QC) and, if required, Ultrasonic (UT) testing is performed to ensure the weld is defect-free.

PIPE SIZING/STRAIGHTENING

The Sizing Section squeezes the welded pipe into the precise roundness, outer diameter, and straightness tolerances specified by the customer.

PIPE CUTTING

The flying cut-off saw attaches to the pipe as it is being produced and cuts the pipe to the length specified by the customer.