EN S355J2H Double-Sided Submerged Arc Welding (DSAW) Steel Pipe

✅ Basic Overview

EN S355J2H DSAW (Double-Sided Submerged Arc Welding) steel pipe is a premium high-strength structural hollow section manufactured to European standard EN 10219 for cold-formed welded structural applications . The "S355J2H" designation indicates a minimum yield strength of 355 MPa (51 ksi) and guaranteed Charpy impact toughness of 27 J at -20°C, making it the preferred choice for cold climate applications, offshore structures, and demanding engineering projects where low-temperature performance is critical .

The "H" suffix denotes a hollow section conforming to EN 10219, while "J2" specifies impact testing at -20°C . 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 .

📋 Name Explanation

🔧 Key Specifications

🔬 Chemical Composition (EN 10219 / EN 10025-2)

*Note: Fully killed steel (FF) containing nitrogen-binding elements (e.g., min. 0.020% total Al) is required .*

📊 Mechanical Properties (EN 10219)

📊 S355 Grade Suffixes: Impact Properties Comparison

*The "J2" suffix is the key differentiator – it guarantees impact toughness at -20°C, which is 20 degrees colder than J0 (0°C) and 40 degrees colder than JR (+20°C) .*

📏 Dimensional Specifications

Wall Thickness Availability by Diameter (S355J2H):

🔧 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

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 (≥ 1.5 × working pressure, ≥ 10 seconds)

Finishing – End processing, beveling, coating, and marking according to specifications

🧪 Testing & Inspection Requirements

🏭 Common Applications

🏗️ Product Standard vs. Material Standard

A key conceptual difference exists in the European (EN) standards system:

Therefore, a complete specification for EN S355J2H DSAW pipe requires:

Material Standard: EN 10025-2 – S355J2 (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 .

🌍 International Equivalents

🛡️ Coating Options

S355J2H DSAW pipe can be supplied with various coatings for corrosion 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

✅ Key Advantages

📝 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) – indoor or warm climate applications

S355J0H – 27 J at 0°C – temperate climate outdoor structures

S355J2H – 27 J at -20°C – cold climates, offshore, demanding applications

S355K2H – 40 J at -20°C – critical applications requiring higher toughness

3. Size Limitations

DSAW manufacturing for S355J2H 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

X-ray inspection available for critical applications

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 S355J2H 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 -20°C, this material is the preferred choice for demanding applications in cold climates, offshore environments, and critical infrastructure where low-temperature performance is essential .

Key features:

Material standard: EN 10025-2 S355J2

Product standard: EN 10219-1/-2 (cold-formed welded structural hollow sections)

Material number: 1.0576

DSAW manufacturing produces pipes from 8" to 72" OD with wall thickness up to 60 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

"J2" suffix guarantees -20°C impact toughness (27 J minimum) – the defining characteristic of this grade

Tighter chemistry controls (P ≤ 0.030%, S ≤ 0.030%) compared to J0/JR grades

Fine grain structure with aluminum deoxidation (≥0.020% Al) for consistent low-temperature properties

Common applications include:

Offshore platforms and marine structures

Arctic and cold climate pipelines

High-rise building construction (support columns, steel frames)

Bridge engineering (main beams, structural members)

Wind turbine towers and piling foundations

Heavy machinery and infrastructure projects

When ordering, specify: EN 10219-1, Grade S355J2H, 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 even higher impact toughness at -20°C (40 J), specify S355K2H instead .