1. Material Classification & Standards
Primary Standard: Japanese Industrial Standard JIS G3114 (Weather-resistant hot-rolled steel).
International Equivalents:
Corten A (ASTM A242, USA)
S355J0WP (EN 10025-5, Europe)
09CuPCrNi-A (GB/T 4171, China).
Type: High-strength low-alloy steel (HSLA) with enhanced atmospheric corrosion resistance.
2. Chemical Composition & Mechanical Properties
Typical Chemical Composition (%)
| Element | C (≤) | Si | Mn | P | S (≤) | Cu | Cr |
|---|---|---|---|---|---|---|---|
| Range | 0.12 | 0.25-0.75 | 0.20-1.50 | 0.07-0.15 | 0.035 | 0.25-0.55 | 0.30-1.25 |
Mechanical Properties
Yield Strength: ≥400 MPa
Tensile Strength: 490-610 MPa
Elongation: ≥18% (50mm gauge length)
Impact Toughness: ≥27J at 0°C (Charpy V-notch).
3. Corrosion Resistance Mechanism
Protective Patina Formation:
Develops a dense, adherent rust layer (FeOOH) when exposed to wet/dry cycles, blocking further oxygen/moisture penetration.
Alloying elements (Cu, Cr, P) catalyze stable rust formation.
Corrosion Rate: 2–8x slower than carbon steel in rural/urban atmospheres.
4. Key Applications
Infrastructure: Bridges, transmission towers, railway wagons.
Architecture: Facades, sculptures (aesthetic rust appearance).
Transport: Shipping containers, highway guardrails.
5. Limitations & Special Considerations
Unsuitable for:
Submerged/constant wet conditions (e.g., underwater structures).
Highly acidic (pH <4) or alkaline (pH >10) environments.
Temperatures >400°C (patina degrades).
Welding: Requires post-weld treatments (tannic acid/primers) to restore corrosion resistance in heat-affected zones.
6. Comparison with Other Weathering Steels
| Property | SMA400AW | Corten A | S355J0WP |
|---|---|---|---|
| Yield Strength | 400 MPa | 345 MPa | 355 MPa |
| Corrosion Resistance | Moderate (urban) | High (industrial) | High (coastal) |
| Cost | Medium | High | Medium-high |
