S355JR is a high-strength, low-carbon structural steel grade (EN 10025) known for its good weldability and toughness, with "S" for structural, "355" for its minimum 355 MPa yield strength, and "JR" indicating it passed a Charpy impact test at room temperature (20°C) with 27 Joules of energy absorption. It's used widely in construction, bridges, heavy machinery, and shipbuilding for load-bearing components requiring strength and durability.
Key Characteristics
Strength: High tensile and yield strength (≥355 MPa).
Weldability: Excellent, due to low carbon content, making it easy to weld.
Toughness: Good impact resistance, guaranteed by the "JR" test.
Classification: Non-alloy, hot-rolled structural steel.
Breakdown of the Name
S: Structural Steel.
355: Minimum Yield Strength in MPa (for thicknesses ≤16mm).
JR: Result of the Charpy impact test (27 Joules at +20°C).
What is the yield strength of S355JR?
The minimum yield strength (ReH) of S355JR is 355 megapascals (MPa) for the most common product forms with a nominal thickness ≤ 16 mm.
Important Technical Specification (EN 10025-2):
This minimum yield strength value decreases for thicker material, as standardized for structural steels to account for manufacturing variations. The exact values are:
For nominal thickness ≤ 16 mm: 355 MPa
> 16 mm to 40 mm: 345 MPa
> 40 mm to 63 mm: 335 MPa
> 63 mm to 80 mm: 325 MPa
> 80 mm to 100 mm: 315 MPa
In summary: While S355JR is classified by its 355 MPa minimum yield strength, this precise value is guaranteed only for sections up to 16 mm thick. For design and engineering calculations, it is essential to use the yield strength value corresponding to the actual product thickness as per the standard table above.
Approximate imperial equivalent: 355 MPa ≈ 51,500 psi (for thickness ≤ 16 mm).
Chemical composition % of steel S355JR (1.0045): EN 10025-2-2004
| Nominal thickness =< 30(mm) CEV max = 0.45 |
| C | Si | Mn | P | S | N | Cu | CEV |
| max 0.24 | max 0.55 | max 1.6 | max 0.04 | max 0.04 | max 0.012 | max 0.55 | max 0.47 |
Mechanical properties of steel S355JR (1.0045)
| Nominal thickness (mm): | to 3 | 3 - 100 | 100 - 150 | 150 - 250 |
| Rm - Tensile strength (MPa) Flat and long products | 510-680 | 470-630 | 450-600 | 450-600 |
| Nominal thickness (mm): | to 16 | 16 - 40 | 40 - 63 | 63 - 80 | 80 - 100 | 100 - 150 | 150 - 200 | 200 - 250 |
| ReH - Minimum yield strength (MPa) Flat and long products | 355 | 345 | 335 | 325 | 315 | 295 | 285 | 275 |
| KV - Impact energy (J) longitud., | -20° 27 |
0° 27 |
+20° 27 |
| Nominal thickness (mm): | to 1 | 1 - 1.5 | 1.5 - 2 | 2 - 2.5 | 2.5 - 3 |
| A - Min. elongation Lo = 80 mm (%) parallel, | 14 | 15 | 16 | 17 | 18 |
| Nominal thickness (mm): | 3 - 40 | 40 - 63 | 63 - 100 | 100 - 150 | 150 - 250 |
| A - Min. elongation Lo = 5,65 √ So (%) parallel, | 22 | 21 | 20 | 18 | 17 |
1. What is S355JR steel?
S355JR is a non-alloy structural steel grade per EN 10025-2, with a minimum yield strength of 355 MPa and guaranteed impact toughness at room temperature (+20°C).
2. What is the yield strength of S355JR?
The minimum yield strength of S355JR is 355 MPa for nominal thickness up to 16 mm, decreasing for thicker sections as per EN 10025-2.
3. What does the 'JR' in S355JR mean?
The 'JR' indicates Charpy V-notch impact testing at +20°C, ensuring a minimum absorbed energy of 27 Joules for basic toughness.
4. Is S355JR equivalent to ASTM A572 Grade 50?
Not exactly. While both have similar yield strength (~345 MPa for A572 Gr 50 vs. 355 MPa for S355JR), they belong to different standards and have different chemical and testing requirements.
5. What are the main applications of S355JR?
It is widely used in heavy construction, bridges, industrial buildings, cranes, machinery frames, and offshore structures requiring higher strength than S275 grades.
6. What is the difference between S355JR and S355J2?
S355JR is impact tested at +20°C, while S355J2 is tested at -20°C, making J2 suitable for cold climate applications.
7. Can S355JR be welded?
Yes, S355JR has good weldability using common methods, though preheating may be required for thicker sections or strict service conditions.
8. What is the chemical composition of S355JR?
Typical composition includes max 0.24% Carbon, max 1.60% Manganese, and controlled phosphorus/sulfur (e.g., P ≤ 0.035%, S ≤ 0.035%).
9. Is S355JR corrosion resistant?
No, it is not corrosion-resistant. Protective coatings such as painting or galvanizing are necessary for outdoor or corrosive environments.
10. What is the difference between S355JR and S275JR?
The main difference is strength: S355JR has a higher minimum yield strength (355 MPa vs. 275 MPa), allowing lighter or stronger designs.
11. What are the mechanical properties of S355JR?
Key properties include yield strength ≥355 MPa (t≤16mm), tensile strength 470-630 MPa, and minimum elongation of 20-22% depending on thickness.
Full specification and details are available on request. The above information is provided for guidance purposes only. For specific design requirements please contact our technical sales staff.
