What is S420n 1.8902 steel plate?

What is S420N 1.8902 Steel Plate?

As a premier exporter and manufacturer of high-quality structural steel plates, Gangsteel specializes in producing EN 10025-3 compliant materials, including the versatile S420N steel grade.

S420N 1.8902 steel plate is a normalized fine-grain structural steel designed for welded constructions requiring high strength and toughness at moderate low temperatures. It is widely used in heavy-duty applications such as bridges, cranes, offshore platforms, and pressure vessels. Our S420N 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 S420N 1.8902 Steel?

S420N steel, designated as 1.8902 under the European standard EN 10025-3, belongs to the family of weldable fine-grain steels. The "N" suffix indicates its suitability for normalized delivery with a minimum impact energy of 40 Joules at -20°C in the longitudinal direction, making it suitable for moderate cold climates and demanding environments. Compared to similar grades like en 10025 3 s420nl normalized structural steel plate, S420N offers balanced low-temperature performance without compromising on strength.

Gangsteel produces S420N 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 S420N 1.8902 Steel Plate

The chemical makeup of S420N 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 S420N 1.8902 Steel Plate

S420N 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 -20°C minimums).

*Notes: Elongation based on Lo = 5.65 √So. Impact values are minimums; higher at warmer temperatures (e.g., longitudinal at 20°C: 63 J). These properties position S420N as a cost-effective choice for structures needing high toughness, outperforming standard S420JR in sub-zero conditions.

Heat Treatment Guide for S420N 1.8902 Steel Plate

S420N steel is 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 S420N 1.8902 Steel Plate

S420N is 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 S420N 1.8902

Why Choose Gangsteel for S420N 1.8902 Steel Plate?

With state-of-the-art mills and a commitment to ISO-certified quality, Gangsteel delivers S420N 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 s420n normalized structural steel plate product page or contact our sales team today.

Summary

S420N 1.8902 steel plate is a high-strength normalized fine-grain structural steel conforming to EN 10025-3, offering exceptional weldability and moderate-temperature toughness. With a yield strength ranging from 340–420 MPa, controlled chemical composition, and superior impact resistance down to -20°C, S420N 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 S420N plates?

Gangsteel supplies S420N plates up to 250 mm thick, with mechanical properties adjusted for thicker sections to maintain structural integrity.

Is S420N suitable for welding without preheating?

Yes, due to its low CEV (max 0.48), S420N 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 S420N 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 S420N be used in offshore structures?

Absolutely—its high toughness at -20°C and corrosion resistance (with proper coatings) make it a preferred material for offshore platforms, as per EN 10025-3 standards.