S235JRH spiral welded steel pipe is a non-alloy structural steel pipe produced by forming steel strip into a helix and welding the seam with submerged arc welding. The JR designation means the material guarantees 27 J impact energy at 20 C, and the H suffix indicates a hollow section per EN 10219-1. Because the pipe is formed from strip, spiral welding can economically produce large diameters that are difficult or impossible to make as seamless pipe, which makes it a workhorse for water transmission, piling and structural applications.
How S235JRH Spiral Welded Pipe Is Manufactured
The production line starts with hot-rolled strip or plate. The strip is uncoiled, leveled and edge-trimmed, then fed into a forming machine that bends it into a continuous spiral at a fixed helix angle. The spiral seam is welded by submerged arc welding from the outside and usually from the inside as well, producing a full-penetration weld. After welding, the pipe is expanded to size, hydrostatically tested, and examined by ultrasonic or X-ray equipment at the seam. Final steps include end beveling, dimensional measurement and marking.
Material Properties of S235JRH
S235JRH is defined in EN 10219-1, which covers cold-formed welded structural hollow sections of non-alloy and fine-grain steels. The guaranteed mechanical properties for the base material are given below.
| Property | Value |
|---|---|
| Minimum yield strength ReH | 235 MPa (for wall thickness up to 16 mm) |
| Tensile strength Rm | 360-510 MPa |
| Impact energy KV | 27 J at 20 C (JR quality) |
| Elongation | Per EN 10219-1, decreasing with wall thickness |
For thicker walls the yield strength steps down slightly, following the standard's table. S235JRH can be welded by all conventional processes and is suitable for painted, galvanized or otherwise coated service.
Key Advantages of Spiral Welded Pipe
Large diameters: spiral mills routinely produce pipe from 219 mm up to 3000 mm in diameter, sizes that seamless mills cannot reach economically.
Flexible wall thickness: the same forming line handles a wide range of wall thicknesses by changing strip width and helix angle.
Cost effectiveness: lower material and forming cost per tonne than seamless or LSAW pipe at large diameters.
Favourable stress distribution: the spiral weld lies at an angle to the main hoop stress, so the load on the weld is a combination of hoop and longitudinal components, which tests have shown to be well handled by full-penetration SAW joints.
Consistent quality: strip feedstock has uniform thickness and surface quality, and the automated SAW process gives reproducible weld properties.
Spiral Welded vs ERW vs LSAW at Large Diameters
| Process | Diameter Range | Seam | Typical Use |
|---|---|---|---|
| Spiral (SAWH) | 219-3000 mm | One continuous spiral SAW seam | Water mains, piling, structural, low-pressure gas |
| ERW | up to about 660 mm | Longitudinal high-frequency weld | Line pipe, casing, general service |
| LSAW | 406-1500 mm | One or two longitudinal SAW seams | High-pressure line pipe, offshore |
Typical Applications
S235JRH spiral welded pipe is used in structural engineering for building frames, bridges and lattice structures, and in civil engineering for water supply mains, sewage and drainage lines, foundation piling and sheet-pile works. With a protective coating it gives decades of service in buried water systems, and its large-diameter capability suits intake and outfall lines, cooling water circuits and agricultural irrigation schemes.
FAQ
What does S235JRH mean?
Per EN 10027-1, S means structural steel, 235 is the minimum yield strength in MPa, JR designates a minimum impact energy of 27 J at 20 C, and H indicates a hollow section supplied per EN 10219-1.
How is spiral welded pipe manufactured?
Steel strip is unrolled, leveled and edge-trimmed, then formed into a continuous helix at a controlled angle. The spiral seam is welded by double-sided submerged arc welding, after which the pipe is expanded, hydrostatically tested and non-destructively examined at the seam.
What is the load-bearing capacity of S235JRH spiral welded pipe?
It depends on diameter, wall thickness and application, not on a single figure. The base material guarantees 235 MPa minimum yield and 360-510 MPa tensile strength; the allowable load is then calculated from the pipe geometry and the governing structural or pressure code.
Why choose spiral welded over seamless or LSAW pipe?
For large diameters, spiral welded pipe is the most economical route because it is formed from strip with a single continuous weld, whereas seamless pipe cannot be made in large sizes and LSAW requires plate and multiple longitudinal seams. The spiral seam also distributes stress over a longer path.
Where is S235JRH spiral welded pipe used?
It is used in structural projects such as building frames and bridges, and in civil engineering for water supply, sewage systems, foundation piling and large-diameter transmission lines where high strength, pressure resistance and cost efficiency are required.
What quality tests are applied to spiral welded pipe?
Standard tests include hydrostatic testing of every joint, ultrasonic or radiographic examination of the spiral seam, tensile and bend testing of the base material and weld, and dimensional checks of diameter, ovality and straightness, per EN 10219-1 and the project specification.
