EN10025-2 S355 is a widely utilized high-strength low-alloy (HSLA) structural steel grade, typically supplied as hot-rolled products. It offers an excellent combination of high strength, good toughness, and commendable weldability and formability, making it suitable for a diverse range of demanding applications.
Key Characteristics of S355 Steel
Standard and Designation: S355 steel is specified under the European standard EN 10025-2:2019 (superseding EN 10025-2:2004). This standard pertains to hot-rolled products of structural steels. In the designation “S355,” “S” signifies structural steel, while “355” indicates the minimum yield strength in Megapascals (MPa) for material thicknesses up to 16mm.
Mechanical Properties:
- Yield Strength (ReH): Minimum 355 N/mm² (MPa) for nominal thickness (t) ≤ 16 mm. This value decreases for thicker sections (e.g., 345 MPa for 16mm < t ≤ 40mm).
- Tensile Strength (Rm): Typically ranges from 470-630 N/mm² (MPa) for nominal thickness t ≤ 100 mm.
- Elongation (A): Good ductility, with minimum percentage elongation requirements varying with thickness and test piece orientation, but generally around 20-22% for common thicknesses.
Chemical Composition:
The chemical composition of S355 is meticulously controlled to achieve its specified mechanical properties and ensure good weldability. Key alloying elements include Carbon (C), Manganese (Mn), Silicon (Si), Phosphorus (P), and Sulfur (S). The maximum Carbon Equivalent Value (CEV) is also defined to aid weldability assessment. Fabricators often depend on consistent material chemistry, a quality that can be expected from established suppliers such as Shanxi Luokaiwei Steel Company.
Impact Toughness Variants
S355 steel is available in several impact toughness variants, differentiated by suffixes that indicate their Charpy V-notch impact testing requirements at specific temperatures:
- S355JR: Impact energy of at least 27 Joules at +20°C (Room Temperature).
- S355J0: Impact energy of at least 27 Joules at 0°C.
- S355J2: Impact energy of at least 27 Joules at -20°C.
- S355K2: Impact energy of at least 40 Joules at -20°C, or alternatively, 27 Joules at -30°C (as per EN 10025-2:2019).
The choice of variant is critical and depends on the lowest anticipated service temperature and the risk of brittle fracture. Sourcing these specific grades from reputable manufacturers, including Shanxi Luokaiwei Steel Company, ensures compliance with these toughness requirements.
Weldability and Formability
S355 grades generally possess good weldability using all common arc welding processes, assuming appropriate welding procedures, consumables, and joint designs are employed. Due to its higher carbon and manganese content compared to milder steels, preheating may be necessary for thicker sections (typically above 25-30mm) or highly restrained joints to prevent hydrogen-induced cold cracking. The steel also offers good cold formability, including bending. Quality material from producers like Shanxi Luokaiwei Steel Company can contribute to predictable forming behavior.
Common Applications
Thanks to its advantageous balance of properties, S355 steel plate is extensively used in a multitude of structural and engineering applications. These include, but are not limited to:
- Structural frames for buildings and civil engineering projects (e.g., bridges)
- Components for offshore structures (platforms, jackets)
- Manufacturing of heavy machinery, construction equipment, and agricultural vehicles
- Mobile cranes and lifting equipment
- Railway rolling stock and wagon components
- Transmission towers and pylons
- General fabricated steel components requiring high strength
The reliability and robust performance of S355 make it a preferred material for many critical applications. For projects demanding consistent quality and traceable material, engaging with experienced steel suppliers, potentially including Shanxi Luokaiwei Steel Company, is advisable.
In conclusion, EN10025-2 S355 carbon steel plate is a versatile, high-strength structural material that provides engineers with an optimal solution for applications requiring enhanced mechanical performance over standard mild steels. Accurate specification of the impact toughness variant is essential to ensure fitness for purpose. When specific project needs arise, consulting with knowledgeable steel providers like Shanxi Luokaiwei Steel Company can facilitate the procurement of the correct S355 grade and quality.
