S355J2 S355J2+N HEA300 hot rolled steel beam
Chemical composition and standards
S355J2 S355J2+N h beam section is a European standard low alloy high strength steel, which complies with the EN 10025 standard.
Typical composition: C≤0.22%, Si≤0.55%, Mn≤1.60%, strictly control P/S≤0.025%, and add micro-alloy elements such as Nb, V, and Ti to improve comprehensive performance.
"+N" means normalized state, through 900-960℃ heat treatment to refine grains, improve anisotropy and weldability.
Mechanical properties
Yield strength: ≥355MPa when thickness ≤16mm, gradually decreases with increasing thickness (such as ≥335MPa when 40-63mm).
Tensile strength: 470-630MPa (S355J2) or 450-680MPa (S355J2+N), with both high strength and good ductility.
Impact toughness: Longitudinal impact energy ≥27J at -20℃, excellent low-temperature fracture resistance.
Corrosion resistance and processability
By adding elements such as Cu and Cr to improve atmospheric corrosion resistance, surface treatment (sandblasting, painting) can adapt to marine or industrial environments.
Low carbon equivalent (CEV≤0.41%), supports arc welding, submerged arc welding and other processes, and has a low risk of welding cracks.
Easy to cut, drill, bend and form, with high processing efficiency.
| parameter | Specifications (typical) | Remark |
|---|---|---|
| Section height (h) | 290 mm | Suitable for heavy load-bearing structure design |
| Flange width (b) | 300 mm | Wide flange for increased stability |
| Web thickness (s) | 9.5 mm | Optimized shear resistance |
| Flange thickness (t) | 14.0 mm | Excellent local compressive performance |
| Unit weight | Approx. 88.3 kg/m | Balance between lightness and strength |
Mechanical properties and design advantages
| Performance Category | Features |
|---|---|
| Fatigue resistance | Low crack growth rate under cyclic loading, suitable for long-term dynamic loading scenarios (such as bridge trusses) |
| Seismic resistance | Elongation after fracture ≥22% (thickness ≤16mm), plastic deformation capacity meets the requirements of seismic design |
| Carrying efficiency | High section modulus (W<sub>y</sub>≈1860 cm³), a single beam can replace multiple sets of ordinary steel |
| compatibility | The flange right angle design is convenient for bolt connection or welding and is suitable for complex steel structure nodes |
