Galvalume Steel Coil (GL / Aluzinc) – 55% Aluminum-Zinc Coating, AZ30-AZ150, Natural Small Spangle for Roofing & PPGL Substrate
Product Overview
Galvalume (GL) steel coil features a unique coating composed of 55% aluminum, 43.4% zinc, and 1.6% silicon, which forms a dense quaternary crystal structure during solidification. This alloy combines the barrier protection of aluminum (forming Al₂O₃ when exposed) with the sacrificial cathodic protection of zinc. The result is a substrate that offers 3 to 4 times the corrosion resistance of standard galvanized steel of the same coating weight. GL coil is the preferred base material for PPGL (Prepainted Galvalume) and is also used bare in applications requiring high heat reflectivity and salt-spray resistance.
Specification Spotlight: Coating Composition & Performance
Our GL coil uses the globally recognized 55% Al – 43.4% Zn – 1.6% Si formula. Under the same coating weight, AZ150 provides equivalent corrosion resistance to Z275, meaning you can achieve superior lifespan with a lighter, more economical coating.
Key Specifications
| Parameter | Range / Options |
|---|---|
| Coating Alloy | 55% Al – 43.4% Zn – 1.6% Si |
| Coating Weight | AZ30 – AZ150 g/m² (double-sided; AZ30 factory standard ~25g actual) |
| Thickness | 0.2 mm – 2.5 mm |
| Width | 800 mm – 1600 mm |
| Spangle | Naturally small, uniform spangle (unique to galvalume) |
| Surface Finish | Bare, chromated, or oiled |
| Heat Resistance | Withstands up to 300°C without discoloration |
| Coil Weight | 3 – 15 MT |
Core Advantages
Superior Corrosion Resistance – Outperforms GI in salt spray, industrial, and marine environments (3× longer lifespan).
High Heat Reflectivity – Reflects ~80% of solar heat, reducing building cooling costs.
Cut-Edge Protection – The aluminum-rich phase forms a stable oxide at sheared edges, preventing red rust propagation.
Economic Coverage – Lower density than pure zinc means ~3% more coverage area per ton.
Applications
PPGL substrate: Base material for premium prepainted coils.
Roofing & wall cladding: Ideal for factories, warehouses, and agricultural buildings.
Heat-related appliances: Oven liners, heat exchangers, chimney pipes, automotive mufflers.
Solar industry: Mounting structures and frames (coastal projects).
