EN S355JRH Double-Sided Submerged Arc Welding (DSAW) Steel Pipe
Basic Overview
EN S355JRH DSAW (Double-Sided Submerged Arc Welding) steel pipe is a high-strength structural hollow section manufactured to European standards, specifically EN 10219 for cold-formed welded structural hollow sections . The "S355JRH" designation indicates a minimum yield strength of 355 MPa (51 ksi) and guaranteed Charpy impact toughness of 27 J at room temperature (+20°C) . The "H" suffix denotes a hollow section conforming to EN 10219 .
DSAW (also known as LSAW - Longitudinal Submerged Arc Welding) is a high-integrity welding process where both inside and outside welds are applied, typically in separate processes, forming a single high-quality weld nugget . This process is specifically designed for large-diameter, thick-wall pipes used in demanding structural applications such as high-rise buildings, bridges, offshore platforms, and piling foundations .
Name Explanation
| Part | Meaning |
|---|---|
| EN | European Norm (standard) |
| S355 | Structural steel grade with minimum yield strength of 355 MPa |
| JR | Impact test requirement: 27 J at room temperature (+20°C) |
| H | Hollow Section – indicates the pipe is a cold-formed welded structural hollow section conforming to EN 10219 |
| DSAW | Double-Sided Submerged Arc Welding – both inside and outside welds are applied; the welding arc is submerged in granular flux during welding |
Key Specifications
| Attribute | Description |
|---|---|
| Product Standard | EN 10219-1/-2 – Cold formed welded structural hollow sections of non-alloy and fine grain steels |
| Material Standard | EN 10025-2 – Defines chemical composition and mechanical properties of the steel plate |
| Steel Grade | S355JRH – Minimum yield strength 355 MPa, 27J impact at +20°C |
| Material Number | 1.0576 (for S355J2H) or 1.0547 (for S355J0H); S355JRH shares similar properties |
| Manufacturing Process | DSAW (Double-Sided Submerged Arc Welding) / LSAW (Longitudinal Submerged Arc Welding) |
| Forming Methods | JCOE (progressive J-C-O forming) or UOE (U-ing, O-ing, Expanding) |
| Size Range | 219 mm to 1829 mm (8" to 72") OD – typical for DSAW |
| Wall Thickness | 5 mm to 50 mm (up to 60 mm for piling applications) |
| Length | 6 m to 12.3 m standard; up to 18.3 m available |
Chemical Composition (EN 10219 / EN 10025-2)
| Element | Maximum % | Notes |
|---|---|---|
| Carbon (C) | 0.22% | Low carbon for good weldability |
| Silicon (Si) | 0.55% | Deoxidizer |
| Manganese (Mn) | 1.60% | Provides strength |
| Phosphorus (P) | 0.035% | Controlled for weldability |
| Sulfur (S) | 0.035% | Controlled for toughness |
| Nitrogen (N) | 0.009% | Controlled; fully killed steel required |
*Note: Fully killed steel (FF) containing nitrogen-binding elements (e.g., min. 0.020% total Al) is required .*
Mechanical Properties (EN 10219)
| Property | S355JRH Requirement | Condition |
|---|---|---|
| Yield Strength (min) | 355 MPa | Thickness ≤ 16mm |
| 345 MPa | 16mm < t ≤ 40mm | |
| Tensile Strength (min) | 510-680 MPa | Thickness ≤ 3mm |
| 470-630 MPa | Thickness > 3mm ≤ 40mm | |
| Elongation (min) | 20-22% | Varies by wall thickness |
| Charpy Impact (JR) | 27 J at +20°C | Guaranteed at room temperature |
S355 Grade Suffixes: Impact Properties
| Designation | Impact Test Temperature | Minimum Impact Energy | Typical Application |
|---|---|---|---|
| S355JRH | +20°C (room temperature) | 27 J | Indoor or warm climate applications, general structural use |
| S355J0H | 0°C | 27 J | Temperate climate outdoor structures |
| S355J2H | -20°C | 27 J | Cold climates, demanding applications |
| S355K2H | -20°C | 40 J | Critical applications requiring higher toughness |
*The "H" suffix indicates Hollow Section, conforming to EN 10219 for cold-formed welded structural hollow sections .*
Dimensional Specifications
| Parameter | Range / Tolerance |
|---|---|
| Outside Diameter | 219 mm to 1829 mm (8" to 72") – typical DSAW range |
| Wall Thickness | 5 mm to 50 mm (up to 60 mm for piling) |
| Diameter Tolerance | ±0.75% of specified OD (typical) |
| Wall Thickness Tolerance | +15% / -12.5% of nominal (typical) |
| Length | 6 m to 12.3 m standard; up to 18.3 m available |
Wall Thickness Availability by Diameter (S355JRH):
| OD (inch) | OD (mm) | Wall Thickness Range (mm) |
|---|---|---|
| 16" | 406 | 6.0 - 14.0 |
| 20" | 508 | 6.0 - 16.0 |
| 24" | 610 | 6.0 - 18.0 |
| 30" | 762 | 7.0 - 21.0 |
| 36" | 914 | 8.0 - 24.0 |
| 40" | 1016 | 8.0 - 26.0 |
| 48" | 1219 | 9.0 - 28.0 |
| 56" | 1422 | 10.0 - 29.0 |
| 60" | 1524 | 10.0 - 29.0 |
| 64" | 1626 | 10.0 - 30.0 |
| 72" | 1829 | 10.0 - 30.0 |
Source:
DSAW/LSAW Manufacturing Process
Double-Sided Submerged Arc Welding (DSAW), also known as Longitudinal Submerged Arc Welding (LSAW), is a high-efficiency process used primarily for large-diameter steel pipes :
Process Description
Welding arc is submerged in granular flux during welding, protecting the weld from atmospheric contamination
Both inside and outside welds are required, usually accomplished in separate processes
The separate welds consume a portion of the other, resulting in a single high-quality weld nugget
Forming Methods
| Method | Description | Typical Diameters |
|---|---|---|
| JCOE | Progressive J-C-O forming steps (J-shape → C-shape → O-shape), expanded after welding | 406-1626 mm (16"-64") |
| UOE | Plate pressed into U-shape, then O-shape, expanded after welding | 508-1118 mm (20"-44") |
Process Steps
Plate Selection – High-quality steel plates chosen according to EN 10219 requirements
Edge Preparation – Edges of the steel plates are beveled to create a V-shaped groove
Forming – Steel plates are formed into cylindrical shapes using JCOE or UOE press or roll bending machines
Tack Welding – Formed plates are tack-welded to maintain the shape
Double Submerged Arc Welding – Pipe seam welded on both interior and exterior surfaces
Cold Expansion – Pipe may be expanded up to 1.5% to achieve final OD dimension; this process can increase yield strength
Ultrasonic Inspection – Seam inspected by continuous ultrasonic automatic flaw detection
Hydrostatic Pressure Test – Each pipe undergoes hydrostatic pressure testing
Finishing – End processing, beveling, coating, and marking according to specifications
Testing & Inspection Requirements
| Test Type | Requirement | Notes |
|---|---|---|
| Chemical Analysis | Per heat lot | Verifies composition limits |
| Tensile Test | Per lot | Verifies yield and tensile strength |
| Flattening Test | Required | Checks ductility and weld integrity |
| Bend Test | Required | Verifies weld integrity |
| Charpy Impact Test | Mandatory for JR | 27 J at +20°C |
| Hydrostatic Test | Each pipe | Pressure integrity verification |
| Ultrasonic Inspection | 100% of weld seam | Continuous automatic flaw detection |
| X-ray Inspection | When specified | For critical applications |
| Dimensional Inspection | 100% | Per EN 10219 tolerances |
| Mill Test Certificate | EN 10204 Type 3.1B | Provided with full test results |
Common Applications
| Application | Description |
|---|---|
| High-Rise Building Construction | Support columns, steel structure frames for skyscrapers and tall buildings |
| Bridge Engineering | Main beams, structural members, bridge piers |
| Offshore Platforms | Marine structures, oil/gas platforms requiring high strength |
| Piling Foundations | Load-bearing piles for buildings and structures |
| Wind Turbine Towers | Large-diameter support structures for wind energy projects |
| Infrastructure Projects | Tunnel supports, retaining walls, highway structures |
| Heavy Machinery | Crane booms, excavator components, agricultural equipment |
| Low-Pressure Fluid Transmission | Water, gas, and oil pipelines |
Product Standard vs. Material Standard
A key conceptual difference exists in the European (EN) standards system:
| Aspect | European System (EN) |
|---|---|
| Philosophy | Modular – Material standards are separate from product standards |
| Material Standard | EN 10025 (defines steel plate properties) |
| Product Standard | EN 10219 (pipe geometry, tolerances, weld quality) |
| Designation | Based on yield strength and toughness (e.g., S355JRH) |
Therefore, a complete specification for EN S355JRH DSAW pipe requires:
Material Standard: EN 10025-2 – S355JR (for the steel plate)
Product Standard: EN 10219-1/-2 (for the finished hollow section)
For DSAW pipe, the correct product standard is EN 10219-1 (cold-formed welded structural hollow sections) . Some manufacturers also produce to EN 10217 (pressure purposes) depending on the application .
S355JRH vs. S355J2H Comparison
| Property | S355JRH | S355J2H |
|---|---|---|
| Impact Test Temperature | +20°C (room temperature) | -20°C |
| Minimum Impact Energy | 27 J | 27 J |
| Typical Application | Indoor or warm climate applications | Cold climates, demanding applications |
| Material Number | 1.0547 (J0H) | 1.0576 |
*S355J2H is specified when guaranteed low-temperature toughness at -20°C is required .*
Coating Options
S355JRH DSAW pipe can be supplied with various coatings for corrosion protection :
| Coating Type | Best For | Key Features |
|---|---|---|
| 3LPE (3-layer polyethylene) | Buried pipelines | Most common; excellent corrosion protection, high impact resistance |
| FBE (Fusion Bonded Epoxy) | Oil & gas pipelines | Strong adhesion, chemical resistance |
| Coal Tar Epoxy | Marine environments | Heavy-duty protection |
| Varnish / Anti-rust oil | Temporary protection | Short-term corrosion protection during transport |
| Bitumen Coating | Buried service | Cost-effective protection |
| Black Oil Coating | Standard mill finish | Temporary protection |
End Finishes
Available end treatments include:
Plain ends (PE) – standard for most applications
Beveled ends (BE) – for field welding (30° bevel angle)
Threaded ends – for mechanical connections
International Equivalents
| Standard | Equivalent Grade | Notes |
|---|---|---|
| ASTM | A572 Grade 50 | Similar yield strength, different impact requirements |
| GB/T | Q355 | Chinese equivalent |
| DIN | St52-3 | Historical German equivalent |
| BS | Grade 50 | Historical British standard |
Key Advantages
| Advantage | Description |
|---|---|
| High Strength | 355 MPa yield – approximately 50% higher than S235 and 30% higher than S275 |
| Excellent Weldability | Low carbon content (≤0.22%) ensures good field weldability |
| Guaranteed Toughness | 27 J at +20°C ensures reliable performance at room temperature |
| Large Diameter Capability | DSAW produces pipes from 8" to 72" OD – ideal for large-diameter applications |
| High Weld Integrity | Double-sided welding creates a single high-quality weld nugget with 100% UT inspection |
| CE/UKCA Marking | Available for construction products under EU/UK regulations |
| Long Service Life | With proper corrosion control, service life can reach 80 to 100 years |
| Versatile Applications | Suitable for structural, piling, and low-pressure fluid applications |
Important Considerations
1. Product Standard Selection
EN 10219 – Structural hollow sections (most common for DSAW)
EN 10217 – Pressure purposes (when hydrostatic testing and pressure ratings are required)
2. Impact Testing Temperature
S355JRH – 27 J at +20°C (room temperature) – suitable for indoor or warm climate applications
For 0°C impact requirements, specify S355J0H
For -20°C impact requirements, specify S355J2H
For higher toughness at -20°C (40J), specify S355K2H
3. Size Limitations
DSAW manufacturing for S355JRH is typically available from 8" to 72" OD
Smaller diameters (under 8") are typically produced by ERW or seamless methods
4. Cold-Formed vs. Hot-Finished
EN 10219 specifically covers cold-formed hollow sections (produced by cold forming without subsequent heat treatment)
Hot-finished structural hollow sections are covered by EN 10210
5. Weld Quality
DSAW produces a single high-quality weld nugget from the combination of inside and outside welds
100% ultrasonic inspection of the weld seam is standard practice
6. Third-Party Inspection
Available inspection services include SGS, BV, Lloyds, TUV
7. Mill Test Certificate
Typically provided as EN 10204 Type 3.1B with full test results
Third-party inspection available upon request
Summary
EN S355JRH Double-Sided Submerged Arc Welded (DSAW) steel pipe is a premium high-strength structural hollow section manufactured to European standards. With minimum yield strength of 355 MPa (51 ksi) – approximately 50% higher than S235 and 30% higher than S275 – and guaranteed Charpy impact toughness of 27 J at room temperature (+20°C), this material offers an excellent balance of strength, weldability, and cost-effectiveness for a wide range of demanding applications .
Key features:
Material standard: EN 10025-2 S355JR
Product standard: EN 10219-1/-2 (cold-formed welded structural hollow sections)
DSAW manufacturing produces pipes from 8" to 72" OD with wall thickness up to 50 mm
Double-sided welding creates a single high-quality weld nugget
JCOE or UOE forming methods ensure precise dimensional accuracy
100% ultrasonic inspection of weld seam ensures quality
"JR" suffix guarantees room temperature impact toughness (27 J at +20°C)
"H" suffix indicates hollow section conforming to EN 10219
Common applications include:
High-rise building construction (support columns, steel frames)
Bridge engineering (main beams, structural members)
Offshore platforms and marine structures
Piling foundations and wind turbine towers
Infrastructure projects (tunnels, retaining walls)
Low-pressure fluid transmission
When ordering, specify: EN 10219-1, Grade S355JRH (or S355J0H/S355J2H if lower temperature impact required), DSAW (Double-Sided Submerged Arc Welded), Size (OD x WT), Length, End Finish (plain/beveled), Coating Requirements, and Mill Test Certificate to EN 10204 Type 3.1 . For applications requiring guaranteed low-temperature toughness, specify S355J2H (-20°C) or S355K2H (40J at -20°C) instead .
