S355NL vs S355N Toughness Comparison

S355NL vs S355N: Toughness Comparison

S355N vs S355NL is a critical comparison for selecting structural steels under the EN 10025-3 standard, which specifies normalized or normalized rolled weldable fine grain structural steels. Both S355N S355NL grades are high-strength, low-alloy steels with fine-grain properties, but their primary difference lies in low-temperature toughness, making them suitable for different environmental conditions. This article compares their toughness, chemical composition, mechanical properties, weldability, and applications, addressing core keywords s355n vs s355nl and s355n s355nl. For more details, visit our EN 10025-3 S355NL normalized structural steel plate.

Overview of S355NL and S355N

S355NL (EN 10025-3)

S355NL is a fine-grain structural steel, normalized or normalized rolled, with:

• S: Structural steel.
• 355: Minimum yield strength of 355 MPa (≤16 mm).
• NL: Normalized, with impact toughness tested at -50°C.

Its superior low-temperature toughness makes it ideal for cold climates like arctic offshore platforms.

S355N (EN 10025-3)

S355N is also a fine-grain structural steel, normalized or normalized rolled, with:

• S: Structural steel.
• 355: Minimum yield strength of 355 MPa (≤16 mm).
• N: Normalized, with impact toughness tested at -20°C.

S355N is suited for moderate-temperature environments, such as general construction in milder climates.

Toughness Comparison

The primary S355N vs S355NL difference is their low-temperature toughness, assessed via Charpy V-notch impact testing:

• S355NL: ≥27 J at -50°C (longitudinal), ensuring excellent resistance to brittle fracture in sub-zero conditions, ideal for arctic or northern applications.
• S355N: ≥27 J at -20°C (longitudinal), suitable for temperate climates but less effective in extreme cold.

S355NL’s -50°C testing makes it superior for environments like offshore platforms in the Arctic, while S355N’s -20°C testing limits it to milder conditions.

Chemical Composition Comparison

The S355N S355NL chemical compositions are nearly identical, with slight differences in impurity limits:

Carbon Equivalent (CEV):

• S355NL: ≤0.43% (≤63 mm).
• S355N: ≤0.43% (≤63 mm).

The S355N vs S355NL difference shows S355NL’s slightly lower phosphorus (0.025% vs 0.030%) and sulfur (0.015% vs 0.025%), enhancing toughness and weldability for colder conditions.

Mechanical Properties Comparison

The S355N S355NL mechanical properties are similar, except for toughness testing temperature:

Strength: Both grades share identical yield (355 MPa) and tensile strengths (470-630 MPa) for similar thicknesses, ensuring comparable load-bearing capacity.
Toughness: S355NL’s -50°C testing makes it superior for sub-zero environments, while S355N’s -20°C testing suits milder climates.
Thickness Range: Both support up to 250 mm, with consistent properties across thicknesses.

Welding and Heat Treatment

• S355NL: CEV ≤0.43% ensures excellent weldability with GMAW or SAW (EN 1011-2). Preheating (100-150°C) for >20 mm; PWHT optional (550-650°C). Consumables: ER70S-6 (GMAW), EM12K flux with EH14 wire (SAW).
• S355N: Identical CEV (≤0.43%) and welding properties, though slightly higher sulfur and phosphorus may require marginally more care during welding.

The S355N vs S355NL welding difference is minimal, with S355NL’s lower impurities offering a slight advantage in weld quality.

Applications

• S355NL:
  • Offshore platforms in cold marine environments (e.g., Arctic seas).
  • Wind towers in sub-zero climates (e.g., northern Europe).
  • Bridges and cranes in arctic regions.
    Its -50°C toughness ensures reliability in extreme cold. See EN 10025-3 S355NL normalized structural steel plate.
• S355N:
  • Building frameworks in temperate climates.
  • Bridges and machinery in moderate conditions.
  • General structural applications where cold toughness is less critical.

The S355N S355NL application difference highlights S355NL’s suitability for colder environments and S355N’s cost-effectiveness for milder conditions.

Which is Better: S355NL or S355N for Toughness?

• Choose S355NLfor:
  • Sub-zero environments (e.g., arctic offshore platforms, northern bridges).
  • Applications requiring guaranteed -50°C toughness.
  • Structures where maximum toughness is critical for safety.
• Choose S355Nfor:
  • Temperate climates where -20°C toughness is sufficient.
  • Cost-sensitive projects with similar strength requirements.
  • General construction in milder conditions.

The S355N vs S355NL toughness comparison favors S355NL for extreme cold, while S355N is more economical for standard conditions.

Equivalent Grades

• S355NL: ASTM A633 Grade E, Q345E (China), TStE 355 (DIN).
• S355N: ASTM A572 Grade 60, Q345D (China), StE 355 (DIN).

Explore EN 10025-3 S420NL normalized structural steel plate for higher-strength options.

Why Choose Gangsteel?

Gangsteel supplies both S355NL and S355N:

• Inventory: Extensive stock in China for rapid availability.
• Sizes: Thickness 6–250 mm, widths 2000/2500/3000 mm, lengths up to 12,000 mm.
• Delivery: 7-30 days to global markets.
• Certifications: EN 10204 3.1/3.2, UT testing (EN 10160), ABS/LR/BV/DNV approvals.
• Processing: Cutting, welding, bending to meet project specifications.

Contact us for EN 10025-3 S355NL normalized structural steel plate.

FAQ

What is the main toughness difference in S355N vs S355NL?
S355NL offers superior toughness with ≥27 J at -50°C, ideal for sub-zero climates like arctic offshore platforms, while S355N provides ≥27 J at -20°C, suitable for temperate regions like general building frameworks.

How does S355N S355NL toughness affect applications?
S355NL’s -50°C toughness ensures reliability in cold environments like northern wind towers, while S355N’s -20°C toughness suits milder climates, such as temperate bridges, reducing costs where extreme cold is not a concern.

Which is better for cold climates in S355N vs S355NL?
S355NL is better for cold climates due to its -50°C impact toughness (≥27 J), ensuring safety in arctic applications like offshore platforms, compared to S355N’s -20°C limit.

Are S355N S355NL strengths similar?
Yes, both S355NL and S355N have identical yield (355 MPa) and tensile strengths (470-630 MPa) for similar thicknesses, making them equally robust for load-bearing, with toughness being the key differentiator.

What are applications of S355N vs S355NL?
S355NL is used in cold-climate offshore platforms, wind towers, and bridges due to its -50°C toughness. S355N suits temperate building frameworks, bridges, and machinery where -20°C toughness is sufficient, offering cost savings.

Can S355N replace S355NL in cold climates?
S355N can replace S355NL in temperate climates where temperatures stay above -20°C, but not in sub-zero conditions like arctic regions, where S355NL’s -50°C toughness is essential for safety and performance.