G90 Galvanized Coil Product Overview
The G90 Galvanized Coil (ASTM A653 designation) features a total zinc coating weight of 0.90 oz/ft² (≈275 g/m²), delivering 15–25 years of corrosion resistance in harsh industrial and coastal environments. Manufactured via continuous hot-dip galvanizing at 450–465°C with a line speed of 120–150 m/min, this cold-rolled carbon steel substrate achieves 240–550 MPa yield strength and ≥15% elongation, making it ideal for structural components, agricultural machinery, and offshore infrastructure. Compliant with ASTM A653 (G90) and EN 10346 (Z275), it outperforms standard galvanized coatings by 40–50% in salt spray resistance (2,000–3,000 hours per ASTM B117).
Key Technical Specifications
1. Dimensional & Coating Properties
- Base Steel Thickness: 0.12–3.5 mm (±3% tolerance per ASTM A924)
- Width: 600–1,500 mm (custom slitting for roll-forming compatibility)
- Zinc Coating:
- Total Weight: 275 g/m² (≈40 µm total thickness)
- Adhesion Strength: ≥4.0 N/mm² (ISO 2409 cross-cut test)
- Surface Finish:
- Zero Spangle (Z): Smooth, spangle-free (Ra ≤0.7 µm) for powder coating
- Minimized Spangle (M): Fine crystalline texture (Ra 1.0–2.0 µm)
2. Mechanical & Chemical Performance
| Grade | Yield (MPa) | Tensile (MPa) | Elongation (%) | Bendability |
|---|---|---|---|---|
| G90 (ASTM) | 240–550 | 300–600 | ≥15 | 0T–3T (1.5 mm) |
| S550GD+Z (EN) | ≥550 | ≥550 | ≥12 | 2T–4T (2.0 mm) |
| SGCD4 (JIS) | ≥220 | ≥300 | ≥22 | 0T–2T (1.0 mm) |
Chemical Composition:
| Element | G90 (ASTM) | S550GD (EN) | SGCD4 (JIS) |
|---|---|---|---|
| Carbon (C) | ≤0.15% | ≤0.25% | ≤0.06% |
| Manganese (Mn) | ≤0.80% | ≤2.50% | ≤0.45% |
| Phosphorus (P) | ≤0.08% | ≤0.10% | ≤0.03% |
Functional Advantages:
- High Manganese Content: Enhances tensile strength for load-bearing applications.
- Zinc-Iron Alloy Layer: 5–8 µm Fe-Zn intermetallic bond prevents coating peel-off during deep drawing.
Corrosion Resistance by Application
| Environment | Recommended Coating | Service Life | Key Industries |
|---|---|---|---|
| Industrial Zones | G90 + Chromate Passivation | 20–25 years | Chemical Tanks, Bridges |
| Coastal (0–500m) | Z275 Overcoat + Paint | 15–18 years | Offshore Platforms |
| Agricultural | G90 (Unpainted) | 12–15 years | Grain Silos, Tractors |
| Urban Infrastructure | G90 + 2-Layer Epoxy | 25–30 years | Highway Guardrails |
Surface Treatment Options
| Code | Treatment | Benefits | Applications |
|---|---|---|---|
| C | Chromate-Free Passivation | RoHS-compliant, enhances salt spray resistance by 35% | Solar panel frames |
| P | Zinc Phosphate + Sealing | Paint adhesion >9 MPa (ISO 2409) | Pre-painted structural beams |
| Q | Oiling + Phosphating | Prevents white rust during海运 transit | Export-ready machinery parts |
| M | Mill Finish | Ready for post-fabrication painting | Custom industrial components |
Global Standard Equivalents
| USA (ASTM) | Europe (EN) | Japan (JIS) | China (GB) |
|---|---|---|---|
| G90 | Z275 | SGCC Z27 | DC51D+Z275 |
| SS550 | S550GD+Z | SGHC550 | B550VK+Z |
Sustainability & Certifications
- Recycled Content: 30–40% (ISO 14021-certified)
- Carbon Footprint: 1.5 tons CO₂/ton (EPD verified)
- Certifications: RoHS, REACH, LEED v4.1, ISO 9001
Packing And Delivery
