What is the difference between S355NL and S355J2 N?

S355NL vs S355J2+N is a critical comparison for selecting structural steels under the EN 10025 standard. S355NL, specified under EN 10025-3, is a normalized fine-grain steel optimized for low-temperature toughness, while S355J2+N, under EN 10025-2, is a normalized non-alloy steel for general use.

This article compares their chemical composition, mechanical properties, weldability, and applications to highlight the S355J2 N vs S355NL differences, addressing core keywords s355nl vs s355j2 n and s355j2 n vs s355nl.

For more details, visit our EN 10025-3 S355J2 N normalized structural steel plate.

S355J2+N is classified under EN 10025-2, which is the standard for non-alloy structural steels. The "+N" indicates that the steel has been normalized or subjected to normalized rolling to improve its grain structure and mechanical properties compared to basic hot-rolled steel.

S355NL is governed by EN 10025-3, the standard for weldable fine-grain structural steels in the normalized condition. The "N" stands for normalized, and the "L" stands for Low-temperature. This grade is specifically designed for environments where the steel must maintain its ductility even when the thermometer drops far below freezing.

A close-up of S355NL steel plates in the GNEE warehouse

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.

A close-up of S355J2+N steel plates in the GNEE warehouse

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.

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.

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.

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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.

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.

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.

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

At GNEE, we understand that material traceability and quality consistency are the backbone of your project. We don't just sell steel; we provide peace of mind through:

• Full Certification: Every order comes with an EN 10204 3.1 or 3.2 Mill Test Certificate, detailing the exact chemical and mechanical properties of your batch.
• Advanced Testing: We offer in-house ultrasonic testing (UT), Z-direction testing (Z15, Z25, Z35), and low-temperature impact testing down to -50°C.
• Global Supply Chain: With a massive inventory and strategic location, we can cut, process, and ship your steel to any port worldwide in record time.
• Technical Support: Our metallurgical experts can help you navigate the S355NL vs S355J2+N steel difference to find the specific grade that balances your budget and technical requirements.

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.

In conclusion, the S355NL vs S355J2+N steel difference boils down to environmental endurance. S355J2+N is the perfect all-rounder for standard construction, while S355NL is the specialized choice for high-integrity structures facing extreme cold or complex dynamic loads. Selecting the correct grade ensures your project meets safety codes while avoiding unnecessary material costs.

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Contact GNEE's technical sales team today for a free quote and a detailed material consultation. Let us help you navigate the S355NL vs S355J2+N steel difference to find the perfect fit for your engineering needs.