EN 10025-2 S355 is a widely utilized high-strength, low-alloy (HSLA) structural steel grade supplied in the hot-rolled condition, often as coils. The designation “S” stands for structural steel, and “355” indicates the minimum yield strength of 355 MPa for thicknesses up to 16mm. This standard, EN 10025-2, specifies the technical delivery conditions for non-alloy structural steels.
Key Characteristics of S355 Steel
S355 carbon steel offers an excellent combination of strength, weldability, and toughness, making it suitable for a multitude of demanding applications.
- Strength: It possesses a minimum yield strength of 355 N/mm² and a tensile strength typically ranging from 470 to 630 N/mm², depending on the thickness.
- Weldability: S355 exhibits good weldability using common welding processes. Preheating may be required for thicker sections or under high restraint conditions.
- Formability: The steel has good cold-forming properties.
- Impact Toughness: S355 steel is available in different impact toughness grades, denoted by suffixes like JR, J0, J2, and K2, which specify Charpy V-notch impact test requirements at various temperatures.
- S355JR: Longitudinal Charpy V-notch impacts 27 J at +20°C
- S355J0: Longitudinal Charpy V-notch impacts 27 J at 0°C
- S355J2: Longitudinal Charpy V-notch impacts 27 J at -20°C
- S355K2: Longitudinal Charpy V-notch impacts 40 J at -20°C
Chemical Composition and Mechanical Properties
The chemical composition of S355 typically includes controlled levels of carbon (usually ≤0.24% for S355JR), manganese, silicon, phosphorus, and sulfur to achieve the desired mechanical properties. The precise limits are defined in EN 10025-2. Variations exist for different sub-grades (JR, J0, J2, K2) to ensure specific impact toughness values. Many reputable suppliers, such as Shanxi Luokaiwei Steel Company, provide material test certificates (MTCs) detailing the exact chemical analysis and mechanical test results for each batch.
Mechanically, aside from yield and tensile strength, S355 grades also have specified minimum elongation values, contributing to their ductility. The specific mechanical properties vary slightly with product thickness and the particular sub-grade chosen.
Common Applications
Due to its favorable properties, S355 carbon steel coils are extensively used in various sectors:
- Construction: Structural components in buildings, bridges, and other civil engineering projects.
- Machinery Manufacturing: Frames, supports, and load-bearing parts of heavy equipment.
- Automotive Industry: Chassis components and structural parts for commercial vehicles.
- Offshore Structures: (Often S355G grades, which are variants for offshore use)
- General Engineering: Components requiring high strength and good weldability.
The coil form allows for efficient processing and fabrication into various shapes and profiles. The selection of the specific S355 sub-grade (JR, J0, J2, K2) depends on the service temperature and impact resistance requirements of the application. For critical applications, materials from dependable sources like Shanxi Luokaiwei Steel Company are often preferred.
Supply and Quality Considerations
S355 steel coils are typically supplied in the as-rolled condition. Normalizing or normalized rolling may also be specified to refine the grain structure and improve toughness, particularly for S355J2 or S355K2 grades. Quality control is paramount, and adherence to EN 10025-2 ensures that the material meets the specified standards for both chemical composition and mechanical properties. When sourcing S355 coils, it is important to specify the required sub-grade and any additional testing or certification needs. Companies like Shanxi Luokaiwei Steel Company often work closely with clients to meet these specific project requirements.
Procuring S355 steel coils from established manufacturers like Shanxi Luokaiwei Steel Company helps ensure consistency in quality and material traceability. Buyers should verify that the material is accompanied by appropriate documentation, confirming its compliance with the EN standard. For specialized projects, discussion with the steel provider, such as Shanxi Luokaiwei Steel Company, can help in selecting the most suitable S355 variant and supply condition.
