S355NH Steel Overview and Uses

S355NH Steel Overview and Uses

At Gangsteel, we’re excited to provide a comprehensive overview of S355NH steel, a high-strength, low-alloy structural steel under EN 10210-1 and EN 10219-1, designed for hollow sections in demanding structural applications. Renowned for its fine-grain structure, 355 MPa yield strength, and -20°C toughness, S355NH is a top choice for structural hollow sections used in construction, infrastructure, and cold-climate projects like pipelines and offshore structures.

Unlike the normalized plate grades in the en 10025 3 normalized steel plate family, S355NH is tailored for hot-finished (EN 10210-1) or cold-formed (EN 10219-1) hollow sections. Gangsteel explores S355NH’s specifications, chemical composition, mechanical properties, and uses, comparing it to grades like en 10025 3 s355n normalized structural steel plate and en 10025 3 s460n normalized structural steel plate. For more details, contact us or visit our en 10025 3 s355n normalized structural steel plate page for related grades.

What is S355NH Steel?

S355NH is a high-strength structural steel for hollow sections under EN 10210-1 (hot-finished) and EN 10219-1 (cold-formed), with a minimum yield strength of 355 MPa. Its designation breaks down as:

• S: Structural steel.
• 355: Minimum yield strength in MPa.
• NH: Normalized or normalized rolled, with impact toughness tested at -20°C.

S355NH is optimized for tubular structures, offering excellent strength, toughness, and weldability for cold climates. Compared to en 10025 3 s355n normalized structural steel plate, S355NH is specifically for hollow sections, while S355N is for plates, but both share similar strength and toughness properties.

Chemical Composition of S355NH Steel

Gangsteel ensures S355NH meets EN 10210-1 and EN 10219-1 chemical composition standards for optimal performance:

Carbon Equivalent (CEV): Capped at 0.43% for both EN 10210-1 and EN 10219-1, calculated as CEV = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15, ensuring excellent weldability. S355NH’s lower sulfur and phosphorus in EN 10219-1 enhance toughness, similar to en 10025 3 s420n normalized structural steel plate.

Mechanical Properties of S355NH Steel

Gangsteel guarantees S355NH’s mechanical properties excel in structural applications:

• Yield Strength: 355 MPa for both hot-finished and cold-formed sections, ideal for moderate-load structures.
• Tensile Strength: 470-630 MPa ensures durability under tensile forces.
• Elongation: ≥22% supports complex tubular designs.
• Impact Toughness: ≥27 J at -20°C ensures reliability in moderate climates, comparable to en 10025 3 s355n normalized structural steel plate.
• Hardness: Typically 150-190 HB, balancing machinability and durability.

Delivery Conditions and Specifications

Gangsteel provides S355NH with specifications outlined in EN 10210-1 (hot-finished) or EN 10219-1 (cold-formed):

• Standards: EN 10210-1:2006 (hot-finished), EN 10219-1:2006 (cold-formed).
• Condition: Normalized or normalized rolled for consistent microstructure.
• Shapes: Circular, square, or rectangular hollow sections.
• Dimensions: Wall thickness 3–40 mm; outer diameter (circular) up to 2500 mm; side lengths (square/rectangular) up to 500 mm.
• Surface: Hot-finished or cold-formed, with optional coating for corrosion protection.
• Certifications: EN 10204 3.1/3.2 certificates, ultrasonic testing (UT) per EN 10160, and approvals from ABS, LR, BV, or DNV.
• Tolerances: Per EN 10210-2 or EN 10219-2 for dimensional accuracy.

S355NH’s hollow section specifications differ from plate grades like en 10025 3 s275n normalized structural steel plate.

Welding and Heat Treatment

S355NH’s low CEV (≤0.43%) ensures excellent weldability:

• Welding: Compatible with GMAW and SAW per EN 1011-2. Preheating typically not required for wall thickness <20 mm; optional for thicker sections (100-150°C); PWHT at 550-650°C optional.
• Consumables: ER70S-6 for GMAW, EM12K flux with EH14 wire for SAW.
• Weld Quality: Enhanced by low sulfur/phosphorus, similar to en 10025 3 s355nl normalized structural steel plate.

Uses of S355NH Steel

Gangsteel supplies S355NH for projects leveraging its properties:

• Construction: Hollow sections for building frameworks, columns, and trusses in moderate climates, benefiting from 355 MPa yield strength.
• Infrastructure: Structural tubing for bridges and railings, supported by ≥22% elongation for complex designs.
• Pipelines: Tubular components in oil, gas, or water systems, leveraging -20°C toughness.
• Offshore Structures: Hollow sections for platforms, relying on 470-630 MPa tensile strength.

For colder climates requiring -50°C toughness, consider en 10025 3 s355nl normalized structural steel plate for plates or S355NLH (EN 10210-1/EN 10219-1) for hollow sections.

Why Choose Gangsteel?

Gangsteel is your trusted source for S355NH:

• Inventory: Extensive stock in China for rapid delivery.
• Sizes: Wall thickness 3–40 mm, diameters/sides up to 2500/500 mm.
• Delivery: Ships globally in 7-30 days.
• Certifications: EN 10204 3.1/3.2, UT testing (EN 10160), ABS/LR/BV/DNV approvals.
• Processing: Cutting, welding, and bending tailored to your needs.

Contact us for S355NH or related grades at en 10025 3 s355n normalized structural steel plate.

FAQ

What is S355NH steel?
S355NH is a high-strength structural steel for hollow sections under EN 10210-1/EN 10219-1, with ≥355 MPa yield strength and -20°C toughness, ideal for construction and pipelines.

What are the key properties of S355NH steel?
S355NH offers a yield strength of ≥355 MPa, tensile strength of 470-630 MPa, ≥22% elongation, and ≥27 J impact toughness at -20°C.

Is S355NH steel weldable?
Yes, S355NH’s CEV ≤0.43% enables easy welding with GMAW or SAW, often without preheating for thinner sections.

What are the uses of S355NH steel?
S355NH is used in building frameworks, bridges, pipelines, and offshore structures in moderate climates, leveraging its strength and toughness.

How does S355NH compare to S355N?
S355NH (hollow sections, EN 10210-1/10219-1) matches S355N’s (plates, EN 10025-3) 355 MPa yield and -20°C toughness but is optimized for tubular applications.

What certifications support S355NH steel?
Gangsteel provides S355NH with EN 10204 3.1/3.2, UT testing (EN 10160), and ABS/LR/BV/DNV approvals.

Summary

S355NH is a high-strength, low-alloy structural steel for hollow sections under EN 10210-1 (hot-finished) and EN 10219-1 (cold-formed), offering a minimum yield strength of 355 MPa and -20°C toughness (≥27 J).

Its fine-grain structure and low CEV (≤0.43%) ensure excellent weldability and durability for applications like building frameworks, bridges, pipelines, and offshore structures in moderate climates.

Gangsteel’s extensive inventory supports wall thicknesses from 3–40 mm and diameters/sides up to 2500/500 mm, with global delivery in 7-30 days and certifications like EN 10204 3.1/3.2.

Compared to S355N (plates), S355NH is tailored for tubular applications, offering similar strength and toughness but optimized for hollow section designs, making it a versatile choice for structural projects.