EN 10025-3 S355NL is a European standard for thermomechanically rolled weldable fine grain structural steel with improved toughness properties at low temperatures.

Standard and Grade Designation

EN 10025-3: Part of the EN 10025 series, which specifies technical delivery conditions for structural steels.

S355NL:

"S" = Structural steel.

"355" = Minimum yield strength (355 MPa at room temperature, thickness ≤16 mm).

"N" = Normalized or normalized rolled (thermomechanical processing).

"L" = Low-temperature impact toughness (suitable for use down to -50°C).

EN 10025-3 S355NL is used in structures requiring high toughness at low temperatures, such as:

1. Construction Machinery: Structural arms and frames of cranes and excavators.

2. Construction and Bridges: Load-bearing components of long-span bridges and steel structures in high-rise buildings.

3. Pressure Vessels and Storage Tanks: Liquid storage tanks and pressure pipelines in low-temperature environments.

4. Marine Engineering: Support structures for offshore platforms (requiring resistance to low-temperature seawater environments).

Processing & Welding:

Weldability: Good (preheat may be required for thick sections).

Heat Treatment: Normalizing improves toughness.

Machinability: Moderate (alloying elements increase hardness).

Comparison with Other S355 Grades:

Conclusion:

EN 10025-3 S355NL is ideal for low-temperature applications where fracture resistance is critical. Its normalized or thermomechanical rolling ensures fine grain structure and consistent performance in harsh environments.