EN S355J2 Structural Steel — Low-Temperature Impact Properties & International Equivalents
EN 10025-2:2019 · Published: 2026-06-14 · Updated: 2026-06-17
S355J2 is the most widely specified structural steel grade in Europe, the workhorse of European construction and heavy engineering. The 'J2' designation is the critical detail: it guarantees a minimum Charpy impact energy of 27 Joules at -20°C —...
S355J2 is the most widely specified structural steel grade in Europe, the workhorse of European construction and heavy engineering. The 'J2' designation is the critical detail: it guarantees a minimum Charpy impact energy of 27 Joules at -20°C — meaning this steel won't brittle-fracture in cold weather. The non-J2 variant (S355JR) only guarantees impact properties at +20°C and should never be used for outdoor structures in climates that experience freezing temperatures.
The S355 family (S355JR, S355J0, S355J2, S355K2) represents increasing low-temperature toughness through increasingly strict control of phosphorus and sulfur content and finer grain size through controlled rolling or normalizing. S355J2 is the minimum grade specifiable for outdoor structures in most of Europe; S355K2 (40 Joules at -20°C) is required for bridges and safety-critical applications.
For North American engineers specifying S355J2: its properties are nearly identical to ASTM A572 Grade 50, with two key differences: (1) S355J2 has a guaranteed impact test at -20°C — A572 Gr 50 does not unless specifically ordered with supplementary requirement S5; (2) S355J2 has tighter phosphorus and sulfur limits (0.025 max each). Always specify the impact test requirement when substituting A572 for S355J2.
Quick Facts
| Category | Carbon Steel |
| Standard | EN 10025-2:2019 |
| Density | 7850 |
| Yield Strength | 355 MPa (≤16mm), 345 MPa (16-40mm), 335 MPa (40-63mm) |
| Tensile Strength | 470-630 MPa |
Global Equivalents & Cross-Reference
| Alternative Standard / Grade | Action |
|---|---|
| ASTM A572 Grade 50 | Compare |
| JIS SM490A | Compare |
| GB Q355D | Compare |
| ISO S355J2 | Compare |
Related Materials
🧮 Material Weight Calculator
Calculate the weight based on this material's density: 7850
Frequently Asked Questions
S355J2 vs S355JR — can I substitute JR for J2?
If the structure will EVER experience temperatures below +20°C — no. S355JR's impact guarantee is at +20°C, meaning it has no guaranteed toughness below room temperature. An outdoor S355JR structure in a climate that freezes is a brittle fracture waiting to happen. The cost difference between JR and J2 is typically only 5-10% — never worth the risk for outdoor applications.
How does S355 compare to S275?
S355 is approximately 30% stronger than S275 (355 MPa vs 275 MPa yield). This means you can use thinner sections for the same load, saving weight and material cost. However, S355's higher strength comes with reduced ductility — S275 typically has 20-23% elongation vs 18-20% for S355. For structures where deformation capacity is critical (seismic design, for example), the S275's extra ductility may be worth the weight penalty.
References & International Standards
- ASTM International. Standard Specifications for Steel & Metal Alloys. astm.org
- International Organization for Standardization (ISO). Metallic Materials — Cross-Reference Database. iso.org
- American Iron and Steel Institute (AISI). Steel Grade Designations & Equivalents. steel.org
- European Committee for Standardization (CEN). EN Steel Standards & Numbering System. cencenelec.eu