difference between s355nl and s275nl

Difference Between S355NL and S275NL: EN 10025-3 Normalized Steel Grades

As a leading exporter and manufacturer of high-quality structural steel plates, Gangsteel specializes in producing EN 10025-3 compliant materials, including S355NL and S275NL grades.

Both are normalized fine-grain structural steels designed for welded constructions with excellent low-temperature toughness.

However, they differ significantly in strength, impact properties, and application suitability.

Our plates are supplied in normalized or normalized rolled conditions, ensuring superior weldability and performance.

For a comprehensive overview of our en 10025 3 normalized steel plate offerings, explore our full range.

Overview of S355NL and S275NL

S355NL (EN 10025-3, designation 1.0546) and S275NL (designation 1.0491) are low-alloy, fine-grain structural steels under EN 10025-3. The "S" denotes structural steel, "355" or "275" indicates minimum yield strength (MPa), and "NL" specifies normalized delivery with longitudinal Charpy V-notch impact testing at -50°C. Both are suited for cold environments, but S355NL offers higher strength, while S275NL is more cost-effective for less demanding applications. Gangsteel produces both in thicknesses up to 250 mm, with certifications ensuring compliance.

Chemical Composition Differences

Both grades have low-carbon profiles for weldability, but S355NL allows slightly higher alloying elements to achieve greater strength (ladle analysis, max % unless noted, ≤100 mm thickness).

*Note: S355NL’s higher Mn and V content boosts strength; both maintain low P/S for toughness and weldability.

Mechanical Properties Comparison

The primary difference is strength: S355NL has higher yield and tensile values, while both ensure -50°C toughness (normalized condition, minimum values).

*Notes: Elongation per Lo = 5.65 √So; transverse impact at -50°C is 16 J for both. S355NL’s higher strength suits heavier loads.

Applications and Selection Criteria

• S275NL: Cost-effective for moderate loads in cold climates (e.g., standard bridges, cranes). See en 10025 3 s275nl normalized structural steel plate.
• S355NL: Preferred for high-strength needs in demanding structures like offshore platforms, heavy-duty bridges, or wind turbine bases. See en 10025 3 s355nl normalized structural steel plate.

For even higher strength, explore en 10025 3 s420nl normalized structural steel plate.

Weldability

Both grades are weldable due to low CEV (S275NL ≤0.40, S355NL ≤0.43). Preheating is typically not needed for thicknesses ≤40 mm; use low-hydrogen fillers (e.g., E7018) per EN 1011-2. S355NL may require slightly higher preheat (>40 mm) due to increased alloying.

Why Choose Gangsteel?

Gangsteel offers ISO-certified S275NL and S355NL plates in custom sizes with global export readiness. Contact us for dual-certified options.

Summary

S355NL and S275NL are EN 10025-3 normalized fine-grain steels with identical -50°C toughness (27 J) but differ in strength: S355NL offers 355 MPa yield (vs. 275 MPa for S275NL) and higher tensile strength, suiting heavier-duty applications. S275NL is more economical for lighter loads. Both excel in cold welded structures.

FAQ

What is the primary difference between S355NL and S275NL?

S355NL has a higher minimum yield strength (355 MPa vs. 275 MPa for ≤16 mm) and tensile strength (470–630 MPa vs. 370–510 MPa), making it stronger for heavier structural demands, while both maintain 27 J impact at -50°C.

Are S355NL and S275NL equally tough at low temperatures?

Yes, both guarantee 27 J longitudinal (16 J transverse) at -50°C, ensuring comparable resistance to brittle fracture in cold environments like arctic infrastructure.

How do their chemical compositions differ?

S355NL allows higher carbon (0.18% vs. 0.16%), silicon (0.50% vs. 0.40%), manganese (0.90–1.65% vs. 0.50–1.50%), and vanadium (0.12% vs. 0.05%) for increased strength, with slightly higher CEV (0.43 vs. 0.40) but identical low P/S levels for toughness.

When should I choose S275NL over S355NL?

Select S275NL for cost-sensitive projects with moderate loads, such as standard bridges or cranes in cold climates, where 275 MPa yield suffices. It’s lighter and cheaper while maintaining -50°C performance.

When is S355NL a better choice than S275NL?

Choose S355NL for high-strength applications like offshore platforms, heavy bridges, or wind turbine towers, where higher yield (355 MPa) and tensile strength reduce material thickness and weight, optimizing structural efficiency.

Are welding requirements different for S355NL and S275NL?

Both are weldable with low CEV, but S355NL’s higher alloying (CEV ≤0.43) may require 50–100°C preheating for thicknesses >40 mm, compared to S275NL (≤0.40). Follow EN 1011-2 for procedures.