S355NL vs S355J2+N Structural Use

S355NL vs S355J2+N: Structural Use

S355NL vs S355J2+N and S355J2+N vs S355NL comparisons are crucial for structural engineers selecting steels under the EN 10025 standard for construction projects. S355NL, specified under EN 10025-3, is a normalized fine-grain structural steel optimized for low-temperature toughness, while S355J2+N, under EN 10025-2, is a normalized non-alloy structural steel for general use in milder conditions. This article compares their properties, focusing on structural use, including chemical composition, mechanical properties, weldability, and applications, addressing core keywords s355nl vs s355j2 n and s355j2 n vs s355nl. For more details, visit our EN 10025-3 S355NL normalized structural steel plate.

Overview of S355NL and S355J2+N

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.

It’s designed for cold climates, ideal for offshore platforms and arctic bridges.

S355J2+N (EN 10025-2)

S355J2+N is a non-alloy structural steel, normalized, with:

• S: Structural steel.
• 355: Minimum yield strength of 355 MPa (≤16 mm).
• J2: Impact toughness tested at -20°C.
• +N: Normalized condition, improving toughness over hot-rolled S355J2.

S355J2+N is cost-effective for general structural applications in temperate climates.

Chemical Composition Comparison

The S355NL vs S355J2+N comparison shows differences in composition affecting toughness and weldability:

Carbon Equivalent (CEV):

• S355NL: ≤0.43% (≤63 mm).
• S355J2+N: ≤0.45% (≤40 mm).

Key Difference: S355NL has lower carbon (0.18% vs 0.20%), sulfur (0.015% vs 0.025%), and includes grain-refining elements (Al, Nb, V), enhancing low-temperature toughness and weldability compared to S355J2+N.

Mechanical Properties Comparison

The S355J2+N vs S355NL mechanical properties differ primarily in toughness:

• Strength: Both grades share identical yield (355 MPa) and tensile strengths (470-630 MPa) for similar thicknesses, ensuring comparable load-bearing capacity for structural use.
• Toughness: S355NL’s -50°C impact testing (≥27 J) makes it superior for sub-zero climates, while S355J2+N’s -20°C testing suits milder conditions.
• Hardness: S355NL has slightly higher hardness (150-190 HB) due to fine-grain structure, compared to S355J2+N (140-180 HB), both supporting machinability.
• Thickness Range: Both support up to 250 mm, but S355NL’s fine-grain structure enhances cold performance.

Weldability for Structural Use

• S355NL: CEV ≤0.43% supports 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). Lower impurities reduce weld imperfections.
• S355J2+N: CEV ≤0.45% requires more preheating (125-175°C for >25 mm) due to higher carbon and sulfur. Same consumables. Slightly higher CEV increases cracking risk.

Key Difference: S355NL’s lower CEV and fine-grain structure make it more weldable, ideal for complex structural welds in cold conditions.

Applications in Structural Use

• 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, meeting Eurocode 3 standards. See EN 10025-3 S355NL normalized structural steel plate.
• S355J2+N:
  • Building frameworks in temperate climates (e.g., commercial structures).
  • Bridges and machinery in moderate conditions.
  • General fabrication where cost is a priority.

The S355NL vs S355J2+N application difference highlights S355NL’s superiority in cold climates and S355J2+N’s affordability for standard conditions.

Which is Better for Structural Use?

• Choose S355NLfor:
  • Cold climates requiring -50°C toughness (e.g., arctic offshore platforms).
  • Structures needing superior weldability and toughness.
  • Thicker sections with consistent low-temperature performance.
• Choose S355J2+Nfor:
  • Temperate climates where -20°C toughness is sufficient.
  • Cost-sensitive projects with standard structural requirements.
  • General construction with less extreme conditions.

The S355J2+N vs S355NL choice depends on environmental conditions and budget.

Equivalent Grades

• S355NL: ASTM A633 Grade E, Q345E (China), TStE 355 (DIN).
• S355J2+N: ASTM A572 Grade 50, Q345B (China), SM490A (JIS).

Explore EN 10025-3 S420NL normalized structural steel plate.

Why Choose Gangsteel?

Gangsteel supplies both grades:

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

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

FAQ

What is the main difference in S355NL vs S355J2+N for structural use?
S355NL is fine-grain, tested at -50°C for cold climates, with better weldability (CEV ≤0.43%); S355J2+N is non-alloy, tested at -20°C, suited for temperate regions with CEV ≤0.45%.

Which is better for cold climates in S355J2+N vs S355NL?
S355NL is superior for cold climates due to its -50°C toughness (≥27 J), ideal for arctic offshore platforms and bridges, unlike S355J2+N’s -20°C limit.

How does weldability compare in S355NL vs S355J2+N?
S355NL (CEV ≤0.43%) requires less preheating (100-150°C vs 125-175°C for >20 mm) than S355J2+N (CEV ≤0.45%), reducing weld imperfections for structural use.

What are applications of S355J2+N vs S355NL?
S355NL is used in cold-climate offshore platforms, wind towers, and bridges; S355J2+N suits temperate building frameworks and general fabrication where cost is key.

Can S355J2+N replace S355NL in structural use?
S355J2+N can replace S355NL in temperate climates with careful welding, but not in sub-zero conditions due to inferior -20°C toughness.

How do strengths compare in S355NL vs S355J2+N?
Both S355NL and S355J2+N have identical yield (355 MPa) and tensile strengths (470-630 MPa) for similar thicknesses, but S355NL’s fine-grain structure enhances cold performance.