When sourcing structural steel tubing for demanding projects, S355J2H is one of the most widely specified European grades. Known for its high yield strength and low-temperature impact resistance, it serves as a reliable backbone across construction, offshore, and heavy machinery industries.
Here is a breakdown of what the designation means, its chemical and mechanical properties, manufacturing standards, and cross-reference equivalents.
Deciphering the Grade Name: What Does S355J2H Stand For?
Under European steel naming conventions (EN 10027), each character in S355J2H reveals a critical performance capability:
- S — Structural Steel: Engineered primarily for structural and load-bearing applications.
- 355 — Yield Strength: Offers a minimum yield strength of 355 MPa (for wall thicknesses $\le$ 16 mm).
- J2 — Impact Toughness: Guarantees minimum impact energy absorption of 27 Joules at -20°C (-4°F).
- H — Hollow Section: Indicates the material is formed into a hollow structural section (pipe/tube).
Key Standards: Hot-Finished vs. Cold-Formed
S355J2H structural hollow sections generally fall under two main European manufacturing standards:
- EN 10210 (Hot-Finished): Produced at elevated temperatures or heat-treated after forming. Offers lower internal stresses, superior dimensional stability, and thicker wall availability.
- EN 10219 (Cold-Formed): Formed cold without subsequent heat treatment. Typically cost-effective, though wall thickness ranges are more limited.
Manufacturing Specs & Available Shapes
| Feature | Details |
| Manufacturing Types | Seamless, ERW, LSAW (SAWL), and SSAW (HSAW) |
| Available Cross-Sections | Circular (CHS), Square (RHS), Rectangular (RHS), Elliptical (EHS) |
| Outer Diameter Limits | Up to 2500 mm (Circular) |
| Wall Thickness Limits | Up to 120 mm (EN 10210) / Up to 40 mm (EN 10219) |
Chemical Composition (Cast Analysis)
S355J2H is a non-alloy steel with strictly controlled impurities to ensure excellent weldability and toughness.
| Element | Carbon (C) | Silicon (Si) | Manganese (Mn) | Phosphorus (P) | Sulfur (S) |
| Max Concentration (%) | 0.22% | 0.55% | 1.60% | 0.030% | 0.030% |
Mechanical Properties
Because material thickness impacts strength performance, the minimum specified yield and tensile values vary depending on section thickness.
1. Strength Requirements (Hot-Finished EN 10210 vs. Cold-Formed EN 10219)
| Standard | Thickness Range (mm) | Min. Yield Strength (ReH) | Tensile Strength (Rm) |
| EN 10210 | ≤16 | 355 MPa | 510 – 680 MPa |
| > 16 ≤40 | 345 MPa | 510 – 680 MPa | |
| > 40≤ 63 | 335 MPa | 510 – 680 MPa | |
| > 63≤80 | 325 MPa | 510 – 680 MPa | |
| EN 10219 | ≤16 | 355 MPa | 510 – 680 MPa |
| > 16 ≤40 | 345 MPa | 470 – 630 MPa |
2. Elongation & Impact Performance
- Elongation ($A$): Minimum 20% to 22% (varies slightly by thickness range).
- Impact Energy ($KV$): Minimum 27 J tested at -20°C.
S355J2H International Grade Equivalents
If you are replacing S355J2H or working on international projects that use different regional standards, the following grades offer similar mechanical profiles:
| Region / Standard | Equivalent Grade Designation |
| USA (ASTM) | ASTM A500 Grade C / ASTM A501 Grade C |
| API Standard | API 5L X52 |
| Japan (JIS) | JIS G 3444 STK500 |
| China (GB) | GB/T 8162 Q345D |
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Our product portfolio covers carbon steel, stainless steel, alloy steel, and other materials, with sizing specifications ranging from DN15 to DN2800. Main products include slip-on flanges, weld neck flanges, high-pressure flanges, elbows, tees, crosses, reducers, caps, bend pipes, manholes, expansion joints, pipe supports and hangers, anti-corrosion/insulated pipe fittings, and complete pipeline assemblies.
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