Galvalume Steel Coil (GL/AZ)
Premium 55% Al-Zn alloy coated steel coil with superior corrosion resistance and heat reflectivity. Widely used in roofing, wall cladding, automotive parts, and appliance manufacturing.
| Base Metal | Cold Rolled Carbon Steel (Q235, SGCC, DX51D) |
| Coating Composition | 55% Aluminum, 43.4% Zinc, 1.6% Silicon |
| Coating Weight (AZ) | AZ50 / AZ70 / AZ100 / AZ150 / AZ185 g/m² |
| Thickness | 0.12mm – 2.0mm (±0.02mm tolerance) |
| Width | 600mm – 1500mm (common: 914mm, 1000mm, 1219mm, 1250mm) |
| Standards | ASTM A792, EN 10346 (DX51D+AZ), JIS G3321 (SGLCC), AS 1397 |
🏗️ Galvalume Steel Coil (GL/AZ)
55% Aluminum-Zinc Alloy Coated Steel — Superior Corrosion Resistance, Heat Reflectivity & Durability for Modern Construction
Product Overview
Galvalume steel coil (also known as GL, Aluzinc, or Zincalume®) is a cold-rolled carbon steel substrate coated with a proprietary alloy of 55% aluminum, 43.4% zinc, and 1.6% silicon through a continuous hot-dip process.
Developed by Bethlehem Steel in 1972, Galvalume has become the global standard for high-performance metal roofing and cladding, offering 2-6 times the corrosion resistance of traditional galvanized steel and exceptional heat reflectivity up to 315°C (600°F).
Our GL steel coils are manufactured to ASTM A792, EN 10346, JIS G3321, and AS 1397 standards with strict quality control at every stage — from substrate selection through coating application to final inspection.
Technical Specifications
| Parameter | Specification |
|---|---|
| Base Metal | Cold Rolled Carbon Steel — Q235B, SGCC, DX51D+AZ, S250GD+AZ |
| Coating Composition | 55% Aluminum + 43.4% Zinc + 1.6% Silicon (Al-Zn alloy) |
| Coating Weight | AZ50 / AZ70 / AZ100 / AZ150 / AZ185 g/m² (total both sides) |
| Thickness Range | 0.12mm – 2.0mm (tolerance ±0.02mm per ASTM A792) |
| Width Range | 600mm – 1500mm (common: 914, 1000, 1219, 1250mm) |
| Coil Weight | 3 – 8 MT per coil (customizable) |
| Inner Diameter | 508mm (20") or 610mm (24") |
| Surface Finish | Regular Spangle, Minimized Spangle, Anti-Fingerprint (AFP) |
| Yield Strength | 275 – 550 MPa (grade dependent) |
| Tensile Strength | 340 – 570 MPa |
| Elongation | ≥16% (0.5mm – 1.0mm), ≥18% (>1.0mm) |
| Standards | ASTM A792, EN 10346, JIS G3321, AS 1397, KS D 3530 |
Coating Weight Selection Guide
| Coating Grade | Weight (g/m²) | Thickness (μm) | Recommended Use |
|---|---|---|---|
| AZ50 | 50 | ~12 | Interior panels, ductwork, appliance backing |
| AZ70 | 70 | ~17 | Light commercial interiors, ceiling panels |
| AZ100 | 100 | ~25 | Standard commercial roofing, wall cladding |
| AZ150 ⭐ | 150 | ~37 | Premium roofing, exposed structures (most popular) |
| AZ185 | 185 | ~46 | Coastal/industrial environments, maximum protection |
Applications
🏠 Roofing & Wall Cladding
The primary application of GL steel. Corrugated, trapezoidal, and standing seam profiles for residential, commercial, and industrial buildings. AZ150 coating provides 25-40 year service life.
🏗️ Structural Steel
Purlins, girts, and light-gauge steel framing for pre-engineered buildings (PEB). The high strength-to-weight ratio of GL enables thinner gauges without sacrificing structural integrity.
🚗 Automotive Components
Heat shields, exhaust system components, and underbody protection panels. Heat reflectivity up to 315°C makes GL ideal for automotive heat management applications.
🏭 HVAC & Ductwork
Air conditioning ducts, ventilation systems, and industrial exhausts. The anti-corrosion properties prevent degradation in humid environments.
☀️ Solar Panel Mounting
GL steel is the preferred substrate for solar panel frames and mounting structures due to its excellent outdoor durability and 25+ year lifespan matching panel warranties.
🔧 Appliance Manufacturing
Oven liners, microwave cavities, toaster housings, and dryer drums. The heat resistance and formability of GL make it ideal for high-temperature appliance components.
Galvalume (GL) vs Galvanized (GI) Comparison
| Property | Galvalume (GL/AZ) | Galvanized (GI/Z) |
|---|---|---|
| Coating Composition | 55% Al + 43.4% Zn + 1.6% Si | 99%+ Pure Zinc |
| Flat Panel Corrosion Life | ⭐ 2-6× longer than GI | Standard baseline |
| Cut-Edge Protection | Good (Al₂O₃ self-healing layer) | ⭐ Excellent (zinc sacrificial) |
| Heat Reflectivity | ⭐ Excellent (up to 315°C) | Limited (~230°C) |
| Surface Appearance | ⭐ Smooth, silver-gray, consistent | Spangled, irregular |
| Paintability | ⭐ Excellent adhesion | Requires primer |
| Weight per m² (same coating) | ⭐ Lighter (lower density) | Heavier |
| Cost (per MT) | ~5-10% higher | ⭐ Lower |
| Best Use Case | ⭐ Roofing, solar, heat applications | ⭐ Post-forming, welding |
Why Choose Our Galvalume Steel?
Factory Direct
Own coating line with 500,000+ MT annual capacity. No middlemen, competitive pricing.
Precision Coating
Air-knife controlled coating thickness with ±3 g/m² accuracy. Consistent quality guaranteed.
Full Certification
ISO 9001:2015, SGS/BV inspected. MTC per EN 10204 Type 3.1 included with every shipment.
Global Logistics
Export to 60+ countries. FOB/CIF/CFR terms. 15-20 day production, sea-worthy packing standard.
Quality Assurance
Every GL coil undergoes 7-stage quality inspection:
- Raw Material Verification — Chemistry analysis and mechanical testing of substrate
- Surface Treatment — Alkaline cleaning + acid pickling + hot-air drying
- Coating Bath Monitoring — Al-Zn alloy composition checked every 4 hours
- Coating Weight Measurement — X-ray fluorescence (XRF) online measurement
- Surface Inspection — Automated vision system + manual spot checks
- Mechanical Testing — Tensile, yield, elongation, bend, and hardness tests
- Final Packaging Audit — Moisture barrier, edge protectors, anti-rust VCI paper
Frequently Asked Questions
Q: What is Galvalume steel and how is it different from galvanized steel?
Galvalume is coated with 55% aluminum-zinc alloy, providing 2-6× longer corrosion life, superior heat reflectivity to 315°C, and better surface consistency compared to pure zinc galvanized coating.
Q: Which coating weight should I choose?
AZ150 is standard for roofing (25-40 year life). AZ100 suits commercial interiors. AZ185 is recommended for coastal/industrial sites. AZ50-70 is for appliance and interior use.
Q: What is the minimum order quantity?
25 MT per specification standard. Mixed containers accepted at 5 MT/spec with 25 MT total minimum.
Q: Can Galvalume be painted?
Yes, GL has excellent paint adhesion and is the preferred substrate for PPGL (prepainted Galvalume). The aluminum-rich surface bonds well with primer and topcoat systems.
Q: How long is production and delivery?
Standard production: 15-20 days. FOB Qingdao/Tianjin delivery: add 3-5 days. CIF to Southeast Asia: total 25-35 days.
📩 Get Your GL Steel Quote Today
Factory direct pricing for Galvalume steel coils. Custom specs welcome. Fast delivery worldwide.