Choosing between galvanized steel coil (GI) and galvalume coil (AZ)? Both offer corrosion resistance, but their coating composition, cost, and best applications differ significantly.
This guide compares:
✔ Coating & corrosion resistance
✔ Cost & lifespan
✔ Best use cases
| Feature | Galvanized Coil (GI) | Galvalume Coil (AZ) |
|---|---|---|
| Coating Composition | 100% Zinc | 55% Aluminum, 43.5% Zinc, 1.5% Silicon |
| Corrosion Resistance | Good (Zinc protects against rust) | Excellent (Aluminum adds extra protection) |
| Heat Resistance | Up to 200°C | Up to 315°C (better for high-temp applications) |
| Cost | Lower | 10-20% higher |
| Lifespan | 20-50 years | 30-60 years (in harsh environments) |
✅ Budget-friendly projects (lower cost than Galvalume)
✅ Indoor applications (less exposure to extreme weather)
✅ General construction (roofing, fencing, structural parts)
✅ Coastal or high-humidity areas (superior saltwater resistance)
✅ High-temperature environments (e.g., industrial chimneys)
✅ Long-term outdoor exposure (e.g., solar panel frames)
Q: Which lasts longer, galvanized or Galvalume?
A: Galvalume generally lasts longer (30-60 years vs. 20-50 years for GI).
Q: Can Galvalume be welded like galvanized steel?
A: Yes, but it requires special techniques to avoid coating damage.
Q: Is Galvalume more expensive than galvanized steel?
A: Yes, typically 10-20% higher due to the aluminum content.