EN10025-3 S420NL alloy special structural steel plates

EN10025-3 S420NL Alloy Special Structural Steel Plates

As a premier exporter and manufacturer of high-quality structural steel plates, Gangsteel specializes in producing EN10025-3 compliant materials, including the versatile S420NL alloy special structural steel plates.

S420NL is a normalized fine-grain alloy special structural steel designed for welded constructions requiring enhanced toughness at low temperatures, down to -50°C.

Ideal for heavy-duty applications in bridges, cranes, and offshore structures, our S420NL alloy special structural steel plates are delivered in normalized or normalized rolled conditions to ensure superior weldability and impact resistance.

For a comprehensive overview of our en 10025 3 normalized steel plate offerings, explore our full range.

What is EN10025-3 S420NL Alloy Special Structural Steel Plates?

EN10025-3 S420NL alloy special structural steel plates refer to S420NL (designated as 1.8912 under EN 10025-3), a high-strength low-alloy (HSLA) fine-grain structural steel. The "NL" suffix indicates normalized delivery with low-temperature impact testing at -50°C (27 J minimum longitudinal), making it suitable for arctic or sub-zero environments. This grade is optimized for welded structures where brittle fracture resistance is critical, distinguishing it from milder variants like S355NL.

Compared to en 10025 3 s420n normalized structural steel plate, S420NL alloy special structural steel plates offer improved low-temperature performance without compromising on strength. Gangsteel produces these plates in thicknesses up to 250 mm, with precise control over chemical composition to meet CEV limits for optimal weldability. Our plates are rigorously tested to comply with international standards, ensuring reliability for global projects.

Chemical Composition of EN10025-3 S420NL Alloy Special Structural Steel Plates

The chemical makeup of S420NL is carefully balanced to provide excellent strength, ductility, and resistance to brittle fracture. Below is the product analysis for nominal thicknesses ≤ 100 mm, with a maximum Carbon Equivalent Value (CEV) of 0.48 (or up to 0.50 in some specifications).

*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 low carbon and controlled alloying ensure minimal risk of cracking during welding.

Mechanical Properties of EN10025-3 S420NL Alloy Special Structural Steel Plates

S420NL exhibits robust mechanical characteristics, with properties varying by thickness to accommodate diverse fabrication needs. All values are for normalized (+N) condition. The table below consolidates yield strength, tensile strength, elongation, and Charpy V-Notch impact energy (longitudinal and transverse at key temperatures, with focus on -50°C minimums).

*Notes: Elongation based on Lo = 5.65 √So. Impact values are minimums; higher at warmer temperatures. These properties position S420NL as a cost-effective choice for structures needing high toughness, outperforming standard S420JR in sub-zero conditions.

Heat Treatment Guide for EN10025-3 S420NL Alloy Special Structural Steel Plates

S420NL alloy special structural steel plates are primarily supplied in the normalized (+N) or normalized rolled condition as per EN 10025-3, which refines the grain structure for improved toughness and weldability.

Normalization Process

• Heating Temperature: Austenitize at 880–920°C (uniform throughout the thickness).
• Soaking Time: Hold for approximately 1 hour per 25 mm of thickness, minimum 30 minutes.
• Cooling: Air cool to room temperature at a controlled rate to avoid excessive hardening.
• Purpose: Refines ferrite-pearlite structure, enhances ductility, and ensures compliance with mechanical properties post-delivery.

If post-delivery heat treatment is needed (e.g., after hot forming), re-normalize to maintain properties. Avoid quenching unless specified, as it may alter toughness.

Welding Heat Treatment Guidelines

• Preheating: Not required for thicknesses ≤ 50 mm; recommend 100–150°C for thicker sections to prevent cold cracking, based on CEV ≤ 0.48.
• Interpass Temperature: Maximum 200°C to preserve fine grain.
• Post-Weld Heat Treatment (PWHT): Optional stress-relief at 550–650°C for 1 hour per 25 mm thickness, followed by slow cooling. Not typically needed due to low hardenability.
• Hot Forming: Perform above 850°C; re-normalize if forming temperature drops below 720°C.

Always consult EN 1011-2 for welding recommendations. Gangsteel provides plates optimized for these processes to minimize heat treatment needs.

Applications of EN10025-3 S420NL Alloy Special Structural Steel Plates

EN10025-3 S420NL alloy special structural steel plates are widely used in:

• Heavy Engineering: Cranes, earthmoving equipment, and load-bearing frameworks.
• Infrastructure: Bridges, viaducts, and offshore platforms where low-temperature ductility is critical.
• Construction: Welded structures in shipbuilding and pressure vessels.

For higher strength needs, consider upgrading to en 10025 3 s460n normalized structural steel plate or en 10025 3 s460nl normalized structural steel plate.

Equivalent Grades to EN10025-3 S420NL

Why Choose Gangsteel for EN10025-3 S420NL Alloy Special Structural Steel Plates?

With state-of-the-art mills and a commitment to ISO-certified quality, Gangsteel delivers S420NL plates tailored to your specifications. Stocked in various sizes and ready for immediate export worldwide. For detailed pricing and availability, visit our en 10025 3 s420nl normalized structural steel plate product page or contact our sales team today.

Summary

EN10025-3 S420NL alloy special structural steel plates offer exceptional weldability and low-temperature toughness, making them a reliable choice for demanding structural applications. With a yield strength ranging from 340–420 MPa, controlled chemical composition, and superior impact resistance down to -50°C, S420NL from Gangsteel ensures durability in bridges, cranes, and offshore projects. Explore our range for customized solutions and competitive global supply.

FAQ

What is the difference between S420N and S420NL steel?

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.