What is S420NL material?

S420NL is a high-strength low-alloy (HSLA) structural steel grade specified in EN 10025-3, the European standard for hot-rolled normalized or normalized rolled weldable fine-grain structural steels. It is designed for applications requiring excellent weldability, high yield strength, and superior toughness at low temperatures down to -50°C, making it ideal for welded constructions in harsh environments. The designation "S420NL" breaks down as follows: "S" for structural steel, "420" for a minimum yield strength of 420 MPa (for thicknesses ≤ 16 mm), and "NL" for normalized delivery with low-temperature impact testing (27 J minimum at -50°C in the longitudinal direction).

This grade is commonly used in heavy engineering, infrastructure, and construction projects where resistance to brittle fracture is critical, such as bridges, cranes, offshore platforms, and pressure vessels. S420NL offers a balance of strength and ductility, outperforming non-fine-grain steels like S420JR in sub-zero conditions.

Gangsteel produces S420NL plates in thicknesses up to 250 mm, with precise control over composition for optimal performance. Our plates are rigorously tested to comply with international standards, ensuring reliability for global projects. For a comprehensive overview of our en 10025 3 normalized steel plate offerings, explore our full range.

Chemical Composition of S420NL Material

The chemical composition of S420NL is tightly controlled to achieve low carbon equivalent (CEV ≤ 0.48) for excellent weldability and fine-grain structure through microalloying (ladle analysis, max % unless noted, ≤100 mm thickness).

*Note: For long products, P and S may be 0.005% higher. If N-binding elements are present, the Al minimum does not apply. Cu above 0.4% may affect hot forming. This composition ensures minimal welding cracks and fine-grain refinement.

Mechanical Properties of S420NL Material

S420NL offers high yield strength and excellent low-temperature ductility, with properties varying by thickness (normalized condition, minimum values).

*Note: Elongation per Lo = 5.65 √So. Impact values increase at higher temperatures. These properties make S420NL ideal for cold-resistant structures.

Heat Treatment Guide for S420NL Material

S420NL is supplied in normalized (+N) condition, involving heating to 880–920°C, soaking, and air cooling to refine grain structure.

• Preheating for Welding: Not required ≤50 mm; 100–150°C for thicker (CEV ≤0.48).
• PWHT: Optional 550–650°C stress-relief.
• Hot Forming: >850°C; re-normalize if <720°C.

Follow EN 1011-2. Gangsteel optimizes for minimal heat treatment.

Applications of S420NL Material

• Heavy Engineering: Cranes, frameworks.
• Infrastructure: Bridges, offshore.
• Construction: Shipbuilding, vessels.

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Why Gangsteel for S420NL Material?

With ISO-certified quality, Gangsteel delivers S420NL plates tailored to specifications, stocked for immediate export. Visit our en 10025 3 s420nl normalized structural steel plate page for details.

Summary

S420NL material is a high-strength normalized fine-grain structural steel (EN 10025-3) with 420 MPa yield, 520–680 MPa tensile, and 27 J impact at -50°C. Its controlled chemistry (CEV ≤ 0.48) and fine-grain structure make it ideal for welded structures in cold environments like bridges and offshore platforms. S420NL from Gangsteel ensures reliability for global projects.

FAQ

What is the difference between S420N and S420NL material?

S420N provides impact testing down to -20°C (40 J longitudinal), while S420NL extends this to -50°C (27 J longitudinal). Both are normalized fine-grain steels under EN 10025-3, but S420NL is ideal for arctic or sub-zero conditions.

What are the maximum thicknesses available for S420NL plates?

Gangsteel supplies S420NL plates up to 250 mm thick, with mechanical properties adjusted for thicker sections to maintain structural integrity.

Is S420NL suitable for welding without preheating?

Yes, due to its low CEV (max 0.48), S420NL exhibits excellent weldability. Preheating is typically not required for thicknesses under 50 mm, but consult project specifications for optimal procedures.

What certifications does Gangsteel provide with S420NL plates?

All plates come with EN 10204 3.1 mill certificates, including chemical analysis, mechanical test results, and impact testing. We also offer third-party inspections like Lloyd's Register or DNV upon request.

Can S420NL be used in offshore structures?

Absolutely—its high toughness at -50°C and corrosion resistance (with proper coatings) make it a preferred material for offshore platforms, as per EN 10025-3 standards.