What is S355NL?
S355NL is a high-strength, non-alloy structural steel grade standardized under EN 10025-3.
"S" = Structural steel
"355" = Minimum yield strength of 355 MPa
"N" = Supplied in normalized condition
"L" = Guaranteed impact energy at –20°C, providing excellent low-temperature toughness
It is widely used in bridges, building structures, heavy engineering, and cold-environment applications, offering high strength, weldability, and dimensional stability.
1. Mechanical Properties
| Property | S355NL Value / Requirement | Standard / Notes |
|---|---|---|
| Yield Strength (ReH) | ≥ 355 MPa | EN 10025-3 |
| Tensile Strength (Rm) | 470–630 MPa | EN 10025-3 |
| Elongation (A5) | ≥ 20% | Typical for structural steel |
| Impact Energy (Charpy V-notch) | ≥ 27 J at –20°C | "L" rating for low temperature |
| Hardness (HB) | 140–190 HB | Brinell hardness |
| Density | 7.85 g/cm³ | Standard steel value |
| Modulus of Elasticity | 210 GPa | Typical for structural steel |
2. Chemical Composition (Typical % by weight)
| Element | C | Si | Mn | P | S | N |
|---|---|---|---|---|---|---|
| % | 0.22 | ≤0.55 | 1.60 | ≤0.035 | ≤0.035 | ≤0.012 |
Note: Carbon equivalent (CE) ≤ 0.45% ensures good weldability.
What standards regulate S355NL?
Key Points of the Standard
Mechanical Properties:
Specifies yield strength, tensile strength, elongation, and Charpy impact energy.
The "L" in S355NL guarantees impact energy ≥27 J at –20°C.
Chemical Composition:
Defines maximum and typical percentages of C, Si, Mn, P, S, N to ensure weldability and toughness.
Delivery Conditions:
"N" = Normalized (mechanically stable)
"L" = Low-temperature impact energy guaranteed
Applications Covered:
Bridges, building frameworks, heavy engineering structures, and cold-environment applications.
What are the typical applications of S355NL?
1. Bridges & Infrastructure
Main beams, trusses, and supporting frameworks
Structural elements exposed to moderate or cold climates
Highway overpasses, viaducts, and pedestrian bridges
2. Heavy Engineering
Machinery bases and industrial equipment frames
Cranes, hoists, and lifting equipment
Storage tanks, silos, and pressure vessels requiring high strength
3. Construction & Building Structures
Roof trusses, columns, and steel frameworks
Multi-story buildings and industrial sheds
Welded frameworks where dimensional stability is critical
4. Cold-Environment Applications
Structures exposed to temperatures down to –20°C
Offshore platforms or coastal constructions in cold regions
Steel components requiring guaranteed low-temperature impact toughness
GNEE Steel also supplies a variety of high-strength steel plates, such as A514 Grade F, A572 Grade 50, A588 Grade A, S355JR, S690Q, SS400, S690QL, Q345B, Q345E, etc. If you want to know more about other types of steel plates, you can call the consultation hotline at +8615824687445 or send an email to info@gneesteels.com. You are welcome to consult us, and we are very willing to answer your questions.
