S355NL Steel Chemical Analysis

S355NL Steel Chemical Analysis

S355NL chemical composition is a key factor defining the performance of this high-strength, low-alloy structural steel under EN 10025-3, which specifies normalized or normalized rolled weldable fine grain structural steels. The S355NL composition is carefully controlled to ensure excellent weldability, toughness, and strength, making it ideal for applications in cold climates like offshore platforms and bridges. This article provides a detailed chemical analysis of S355NL, its impact on properties, and applications, addressing core keywords s355nl chemical composition and s355nl composition. For more details, visit our EN 10025-3 S355NL normalized structural steel plate.

What is S355NL Steel?

S355NL is a fine-grain structural steel under EN 10025-3, designed for high strength and low-temperature performance. Its designation indicates:

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

The S355NL chemical composition is tailored to achieve a refined microstructure, enhancing toughness and weldability for demanding applications.

S355NL Chemical Composition

The S355NL composition is specified by EN 10025-3 for both ladle and product analysis, ensuring consistency and performance:

Key Elements and Their Roles

• Carbon (C): Limited to ≤0.18% to minimize hardness, enhancing weldability and toughness, reducing the risk of brittle fracture in cold environments.
• Manganese (Mn): Range of 0.90-1.65% boosts strength and toughness, contributing to the steel’s load-bearing capacity.
• Phosphorus (P) and Sulfur (S): Low levels (≤0.025% and ≤0.015%) reduce inclusions, improving weld quality and low-temperature performance.
• Aluminum (Al): Minimum 0.02% promotes fine-grain structure, enhancing toughness at -50°C.
• Niobium (Nb) and Vanadium (V): Microalloying elements refine grain size, improving strength and toughness for structural applications.

Carbon Equivalent (CEV): ≤0.43% for thicknesses ≤63 mm, calculated as CEV = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15, ensures excellent weldability, minimizing cold cracking risks during fabrication. The S355NL chemical composition supports its use in demanding welded structures.

Impact on S355NL Properties

The S355NL composition directly influences its mechanical properties:

• Strength: Low carbon and high manganese achieve a minimum yield strength of 355 MPa and tensile strength of 470-630 MPa, ideal for load-bearing structures.
• Toughness: Low sulfur, phosphorus, and nitrogen, combined with grain-refining elements (Al, Nb, V), ensure ≥27 J impact energy at -50°C, critical for cold climates.
• Weldability: Low CEV (≤0.43%) supports efficient welding with minimal preheating, reducing fabrication costs.
• Ductility: Fine-grain structure enhances elongation (≥22%), allowing flexibility in structural designs.

Mechanical Properties Overview

To contextualize the impact of the S355NL chemical composition, here are its key mechanical properties:

These properties, driven by the S355NL composition, ensure reliability in high-stress, cold-climate applications.

Welding and Heat Treatment

The S355NL chemical composition supports excellent weldability:

• Welding: Compatible with GMAW (Gas Metal Arc Welding) and SAW (Submerged Arc Welding) per EN 1011-2. Preheating (100-150°C) is recommended for thicknesses >20 mm to prevent hydrogen-induced cracking; no preheat is needed for thinner plates.
• Post-Weld Heat Treatment (PWHT): Optional at 550-650°C for critical welds, rarely required due to low CEV.
• Consumables: ER70S-6 (GMAW), EM12K flux with EH14 wire (SAW).

The low carbon and impurity levels in the S355NL composition minimize weld imperfections, ensuring robust joints for structural applications.

Applications of S355NL Steel

The S355NL chemical composition enables its use in:

• Offshore Platforms: Resists fatigue and brittle fracture in cold marine environments, such as the North Sea or Arctic regions, with corrosion-resistant coatings for added durability.
• Wind Turbine Towers: Supports heavy loads in sub-zero climates, ideal for northern wind farms, with excellent fatigue resistance.
• Bridges and Cranes: Load-bearing components in cold regions like Scandinavia, meeting Eurocode 3 standards for safety and design.
• Pressure Vessels: Suitable for low-temperature storage or processing systems, such as LNG tanks, due to its -50°C toughness.

Explore related grades like EN 10025-3 S420NL normalized structural steel plate for higher-strength applications.

Equivalent Grades

The S355NL composition aligns with international equivalents:

For a related grade, see EN 10025-3 S355N normalized structural steel plate.

Why Choose Gangsteel for S355NL Steel?

Gangsteel is a leading supplier of S355NL:

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

Request a quote for EN 10025-3 S355NL normalized structural steel plate.

FAQ

What defines the S355NL chemical composition?
The S355NL chemical composition includes low carbon (≤0.18%), manganese (0.90-1.65%), low sulfur (≤0.015%), and grain-refining elements (Al, Nb, V) to ensure toughness, strength, and weldability, with CEV ≤0.43% for fabrication ease.

How does the S355NL composition affect its properties?
The S355NL composition provides a yield strength of ≥355 MPa, tensile strength of 470-630 MPa, elongation ≥22%, and impact toughness ≥27 J at -50°C, ideal for cold-climate structural applications due to its fine-grain structure.