Spiral Welded SAW Pipe

Complete Guide: What It Is, How It's Made, Dimensions and Standards (EN 10217 | API 5L)

Spiral welded pipe with SAW (Submerged Arc Welding) is the reference solution for transporting natural gas, oil, industrial water, and other pressurized fluids on a large scale. The combination of the spiral forming process and the submerged arc welding technique makes it one of the most reliable and efficient options available on the market. In this guide you will find complete information about how this pipe works, how it is produced, what dimensions are available, and what international standards govern it.

What Is SAW Spiral Welded Pipe?

SAW spiral welded pipe is manufactured by continuously winding a flat hot-rolled steel strip (hot-rolled coil) in a spiral, followed by welding the brought-together edges using the SAW process — submerged arc welding under a flux layer.

Unlike other methods of producing welded pipes, in spiral pipe the weld seam follows a spiral path along the pipe body. This geometry distributes mechanical stresses evenly around the pipe's circumference, providing excellent resistance to internal pressure, especially at large diameters.

The SAW process is distinguished by depositing filler material beneath a layer of granular flux, which protects the weld pool from oxidation and ensures a seam with deep penetration, high strength, and superior metallurgical properties. In high-quality spiral SAW pipes, welding is performed in two passes: first on the inside (interior weld – ISAW), then on the outside (exterior weld – OSAW), guaranteeing complete integrity of the joint throughout the full wall thickness.

The Production Process of SAW Spiral Pipe

The production of SAW spiral pipe is a continuous and highly automated process, structured in several distinct stages:

Step 1 – Receipt and Preparation of the Steel Strip (Coil) The raw material is hot-rolled steel strip, delivered in coils with width and thickness pre-specified according to the order. Before entering the production line, the strip is inspected dimensionally and chemically, verifying conformity with the required material grades (e.g.: L360, L415, L450, L485 per API 5L; or P235, P265 per EN 10217).

Step 2 – Uncoiling, Straightening, and Edge Preparation The coil is unrolled and passed through a straightening roller system to eliminate any residual deformation. Subsequently, the strip edges are milled or ground to achieve a precise geometric profile, ensuring optimal contact between the edges to be welded.

Step 3 – Spiral Forming The steel strip is fed into a forming device (forming head) that progressively bends it, imparting a spiral path at the angle corresponding to the desired outer diameter. The helical angle is precisely calculated based on the strip width and the targeted pipe diameter. This flexibility allows production of a wide range of diameters without a complete equipment change.

Step 4 – Interior and Exterior SAW Welding Immediately after forming, the edges of the spiraled strip are continuously welded. The SAW process involves an electric arc generated between a consumable electrode (welding wire) and the workpiece, the entire assembly being covered by a granular protective flux. This prevents oxidation and ensures the metallurgical quality of the seam.

• Interior weld (ISAW): first pass, secures the weld root

• Exterior weld (OSAW): second pass, completes and reinforces the joint

• Result: full penetration seam, with no gaps or lack of fusion

Step 5 – Quality Control and Non-Destructive Testing (NDT) Each finished pipe is subjected to a rigorous inspection program, including:

• Ultrasonic inspection (UT) along the entire length of the spiral seam – detecting cracks, inclusions, or lack of fusion

• Ultrasonic inspection of the pipe body (body UT) – detecting defects in the base material

• Hydraulic pressure testing (hydrotest) at the pressure specified by the standard

• Dimensional measurements: outer diameter, ovality, wall thickness, length

• Visual interior and exterior inspection of the surface and seam

• Mechanical testing on samples: tensile, guided bend, Charpy impact

Step 6 – Marking, Documentation, and Dispatch Conforming pipes are marked with full traceability data: manufacturer, standard, material grade, dimensions, steel heat number, lot number. Technical documentation accompanies each delivery and includes material certificates and inspection reports required by the standard.

International Standards: EN 10217 and API 5L

SAW spiral pipe can be manufactured and certified in accordance with several international standards, depending on the final application, geographic region, and project requirements. The most important are the European standard EN 10217 and the American standard API 5L, both widely accepted in the global market.

European Standard EN 10217

EN 10217 is the European reference standard for welded steel pipes intended for pressure applications. It is structured in several parts, of which the most relevant for SAW spiral pipe are:

EN 10217-1 – Welded steel tubes for pressure purposes; non-alloy steel tubes with specified properties at room temperature. Covered by this part are pipes used in industrial water networks, HVAC circuits, compressed air, technical gases, and other applications at ambient temperatures. Typical material grades are P235TR1, P235TR2, P265TR1, and P265TR2.

EN 10217-5 – Welded steel tubes for pressure purposes; electric welded non-alloy and alloy steel tubes with specified elevated temperature properties. This part applies to pipes used in thermal installations, steam generators, boilers, and any systems operating at elevated temperatures. Typical material grades include P235GH and P265GH.

Technical documentation provided in accordance with EN 10217 must obligatorily include:

• Material certificate EN 10204 – Type 3.1 (inspection carried out by the manufacturer's laboratory) or Type 3.2 (inspection carried out by an independent third party)

• CE Declaration of Conformity

• NDT and hydrotest inspection reports

American Standard API 5L

API 5L (American Petroleum Institute – Line Pipe Specification) is the worldwide reference standard for pipelines used in the oil and gas industry. It is recognized and used in projects on all continents, from onshore gas and oil pipelines to offshore submarine pipelines.

API 5L defines two Product Specification Levels (PSL):

PSL1 – standard quality level, with basic requirements regarding mechanical and chemical properties. Suitable for applications with moderate pressure and temperature requirements.

PSL2 – higher quality level, with additional strict requirements regarding: toughness at low temperatures (Charpy testing), maximum tensile strength limits, chemical composition control (carbon equivalent), extended non-destructive inspection, and weldability requirements. PSL2 is mandatory in offshore projects, high-pressure gas pipelines, and any application involving elevated safety risks.

The most commonly used API 5L material grades for SAW spiral pipe are presented in the table below:

Values are indicative; exact requirements differ between PSL1 and PSL2 and may vary depending on the applicable edition of the standard.

A key aspect of API 5L is the material traceability system – each pipe delivered under this standard must be traceable back to the steel heat from which it was manufactured, and material certificates must reflect all tests performed on the batch.

Available Dimensions for SAW Spiral Pipe

One of the main advantages of the spiral SAW process is the ability to produce extremely large diameters, difficult or impossible to achieve by other methods. The typical dimensional range available is:

• Outer diameter: from 21.3 mm (½") to 1016 mm (40") and even larger on special order

• Wall thickness: from 2 mm to 20 mm (greater thicknesses available on request)

• Delivery length: 6–12 metres standard (non-standard lengths available on order)

• EN 10217 materials: P235TR1, P235TR2, P265TR1, P265TR2, P235GH, P265GH

• API 5L materials: Grade B, X42, X52, X60, X65, X70, X80 – PSL1 and PSL2

The table below presents indicative dimensions and weights for SAW spiral welded pipe for liquid and gas transport:

Weights are approximate and may vary depending on tolerances, execution, and supplier.

Fields of Application

SAW spiral pipe is the solution of choice across a wide range of industrial and infrastructure applications where high reliability, large diameters, and certification to international standards are required:

• Natural gas transport – main and secondary gas pipelines, distribution at low, medium, and high pressures (API 5L PSL2, EN 10217-1)

• Crude oil and petroleum product transport – onshore and offshore pipelines, including submarine pipelines

• Industrial and pressurized drinking water networks – water mains, pumping stations, industrial distribution

• Large-capacity district heating and HVAC systems – heat carrier transport at elevated temperatures (EN 10217-5, GH grades)

• Offshore installations – continental shelf pipelines, risers, seabed pipelines (API 5L PSL2, special toughness requirements)

• Compressed air and industrial technical gases – nitrogen, CO2, oxygen, hydrogen (subject to material compatibility)

• Large-capacity industrial drainage and sewerage

Why SAW Spiral Pipe?

• Large diameters at efficient cost – the spiral process allows fabrication of very large diameters from a narrow strip, without requiring large-scale pressing equipment

• High-quality SAW seam – full penetration, superior mechanical strength, minimal defects due to granular flux protection

• Dual interior and exterior welding – eliminates the risk of internal defects and ensures integrity throughout the entire wall section

• Online NDT inspection – ultrasonic control is performed in real time on the production line, prior to delivery

• Dimensional flexibility – diameter can be adjusted by modifying the forming angle, without a complete line changeover

• Dual EN 10217 and API 5L certification – the same pipe can be certified to both standards, simplifying procurement for international projects

• Complete traceability – EN 10204 certificate (3.1 or 3.2), NDT reports, hydrotest, steel heat data

• Compatibility with standard EN and ASME fittings, flanges, and valves – rapid integration into existing assemblies

Request a Quote for SAW Spiral Welded Pipe

Titan Steel Trading supplies SAW spiral welded pipes in accordance with EN 10217-1, EN 10217-5, and API 5L (PSL1 and PSL2), across an extensive dimensional range, with complete technical documentation. Our team of specialists will analyse the technical requirements of your project and provide a customised offer with optimal delivery timelines.

We invite you to contact us for technical specifications, availability, and pricing:

https://titansteelco.ro/welded-steel-pipes-pressure

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