1. Mechanical Properties
S355J0H is a low-alloy high-strength structural steel designed for hollow sections under the EN 10210-1 standard . Key mechanical characteristics include:
Yield Strength: ≥355 MPa (for thickness ≤16mm), decreasing to ≥275 MPa for thicker sections (e.g., 250mm) .
Tensile Strength: 470–630 MPa, ensuring durability under high-stress conditions .
Elongation: ≥21% (longitudinal), demonstrating excellent ductility .
Impact Toughness: ≥27J at 0°C, making it suitable for moderate低温 environments .
2. Chemical Composition
The alloy’s composition balances strength and weldability:
| Element | Range (%) | Role |
|---|---|---|
| Carbon (C) | ≤0.22 | Enhances hardness |
| Manganese (Mn) | 1.00–1.60 | Strengthens and refines grain |
| Silicon (Si) | ≤0.55 | Improves deoxidation |
| Phosphorus (P) | ≤0.035 | Reduces brittleness |
| Sulfur (S) | ≤0.035 | Enhances machinability |
| Niobium (Nb) | ≤0.09 (optional) | Refines grain for toughness |
| Additional trace elements (e.g., Cr ≤0.30%, Cu ≤0.55%) improve corrosion resistance . |
3. Physical Properties
Density: 7.85 g/cm³, typical for structural steels .
Thermal Conductivity: ~45 W/m·K, suitable for heat dissipation .
Thermal Expansion: 11.2×10⁻⁶/°C (20–100°C), ensuring dimensional stability .
4. Processing and Fabrication
Welding: Requires preheating (100–150°C) to avoid cracking. Compatible with arc welding and gas-shielded methods .
Cold Forming: Can bend up to 180° without cracking, ideal for complex structural shapes .
Heat Treatment: Often supplied in hot-rolled or normalized states to optimize microstructure .
5. Applications
S355J0H is widely used in:
Construction: High-rise buildings, bridges (non-Arctic regions) .
Machinery: Crane booms, excavator frames .
Infrastructure: Pressure vessels, pipelines (moderate zones) .
Standards and Equivalents
EN 10210-1: Primary manufacturing standard .
China GB/T Equivalent: Q355C (tested at 0°C) .
Key Advantages
Superior balance of strength, ductility, and weldability.
Cost-effective for projects where extreme performance is unnecessary
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