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How to Choose the Right Galvalume Steel Coil (GL)
Choosing the right Galvalume Steel Coil (GL) is essential for ensuring long-term durability, corrosion resistance, and performance in construction and manufacturing projects.
In this professional guide by Hengze Steel Group, you’ll learn how to evaluate coating grades (AZ50–AZ150), compare Galvalume vs Galvanized Steel, and understand the role of standards like ASTM A792 / EN 10346.
Whether for roofing, wall cladding, or industrial applications, Hengze Steel provides high-quality Aluzinc and pre-painted GL coils (PPGL) that combine strength, longevity, and cost efficiency — making them the ideal choice for modern engineering and architectural needs.
Table of Contents
- 1. Introduction: Why Choosing the Right GL Coil Matters1. Introduction: Why Choosing the Right GL Coil Matters
- 2. What Is Galvalume Steel Coil (GL)?2. What Is Galvalume Steel Coil (GL)?
- 3. Galvalume vs Galvanized Steel — Key Differences3. Galvalume vs Galvanized Steel — Key Differences
- 4. Key Factors to Consider When Choosing Galvalume Steel Coils4. Key Factors to Consider When Choosing Galvalume Steel Coils
- 5. Application-based Selection Recommendations5. Application-based Selection Recommendations
- 6. Common Mistakes and Potential Risks6. Common Mistakes and Potential Risks
- 7. Conclusion: How to Make a Smart Choice7. Conclusion: How to Make a Smart Choice
1. Introduction: Why Choosing the Right GL Coil Matters
In today’s construction and manufacturing industries, Galvalume Steel Coils (GL) — also known as Aluzinc Steel Coils — are increasingly replacing traditional galvanized steel due to their excellent corrosion resistance and extended lifespan.
As one of the leading Galvalume Steel Coil manufacturers in China, Hengze Steel Group provides high-performance GL coils that meet ASTM, EN, and JIS standards, ensuring durability and reliability across industrial and architectural applications.
Selecting the right GL coil helps prevent premature corrosion, ensures structural safety, and optimizes long-term cost efficiency. This guide offers detailed insights on how to choose the right Galvalume Steel Coil for your project.
2. What Is Galvalume Steel Coil (GL)?
Galvalume Steel Coil is a hot-dip aluminum-zinc coated steel product. Its coating consists of:
55% Aluminum (Al) for barrier protection
43.4% Zinc (Zn) for sacrificial corrosion resistance
1.6% Silicon (Si) for adhesion and heat resistance
This Al-Zn alloy coating offers both the corrosion resistance of zinc and the heat reflectivity of aluminum, making it ideal for roofing, cladding, and industrial equipment.
Common Standards: ASTM A792 / EN 10346 / JIS G3321
Alternative Names: Aluzinc Steel Coil, GL Coil, 55% Al-Zn Coated Steel
3. Galvalume vs Galvanized Steel — Key Differences
| Feature | Galvanized Steel Coil | Galvalume (GL) Steel Coil |
|---|---|---|
| Coating Composition | 100% Zinc | 55% Al + 43.4% Zn + 1.6% Si |
| Corrosion Resistance | Moderate (15–20 years) | Excellent (40–60 years) |
| Heat Resistance | Up to 200 °C | Up to 315 °C |
| Surface Appearance | Bright, spangled | Smooth, metallic silver |
| Edge Protection | Weak | Strong self-healing ability |
| Cost Efficiency | Lower upfront | Lower lifetime cost |
✅ Conclusion:
Galvalume Steel outperforms galvanized steel in durability, corrosion protection, and heat resistance, making it the ideal choice for roofing, wall panels, and long-term structures.
4. Key Factors to Consider When Choosing Galvalume Steel Coils
4.1 Steel Grade
The mechanical strength and forming capability depend on the steel grade:
CS: Commercial forming applications
FS: Deep drawing applications
SS: Structural use requiring higher tensile strength
Hengze Steel Group offers customized GL coils in different grades and tensile strengths to meet diverse construction and industrial needs.
4.2 Coating Weight & Composition
Coating weight is crucial for long-term performance. Common grades include:
AZ50 / AZ100 / AZ150 (representing coating weight in g/m² or oz/ft²)
For outdoor or coastal applications, AZ150 or higher is recommended.
4.3 Surface Treatment & Pre-painted Options
Bare GL Coil: Ideal for later painting or indoor applications.
Pre-painted GL Coil (PPGL): Factory-applied color coatings with excellent UV and corrosion resistance.
Optional finishes: Anti-fingerprint, Matte, or Chromate-free.
Hengze Steel Group’s PPGL coils are available in PVDF, SMP, and polyester coatings, providing both functional and aesthetic advantages for modern architecture.
4.4 Dimensions & Processing
Typical specifications:
Thickness: 0.13 – 1.5 mm
Width: 600 – 1250 mm
Coil Weight: 3 – 10 MT
Confirm processability for bending, shearing, or punching to ensure coating integrity.
4.5 Manufacturing Standards & Certifications
Select coils that comply with:
ASTM A792 / EN 10346 / JIS G3321
Quality systems: ISO 9001, CE, SGS certified
Hengze Steel Group strictly implements these standards, ensuring stable coating thickness, adhesion, and salt-spray resistance across all shipments.
5. Application-based Selection Recommendations
Roofing & Wall Cladding
Use AZ150 coating for maximum corrosion protection.
Choose PVDF pre-painted GL coils for long-term color stability.
Industrial & Agricultural Buildings
Opt for AZ100 coatings for cost-effective protection.
Consider anti-fingerprint finishes for ammonia or moisture exposure.
HVAC & Equipment Enclosures
Choose heat-resistant GL coils (up to 315 °C).
Recommended thickness: 0.4–0.8 mm for precision fabrication.
6. Common Mistakes and Potential Risks
❌ Selecting based on price only — ignoring coating or steel grade.
❌ Missing certifications or supplier quality checks.
❌ Using indoor-grade coils in coastal areas.
✅ Hengze Steel Group recommends evaluating environmental exposure, coating type, and supplier reliability before purchase to ensure long-term performance.
7. Conclusion: How to Make a Smart Choice
When choosing Galvalume Steel Coils, always consider:
Standard compliance (ASTM A792 / EN 10346).
Coating grade suitable for the application (AZ150+ for exterior).
Supplier credibility and quality assurance.
Hengze Steel Group, with advanced production lines and international certifications, delivers high-quality Galvalume and Pre-painted Galvalume Coils (PPGL) trusted by clients in Europe, the Middle East, and Southeast Asia.
In short:
Choose Hengze Steel Group’s Galvalume Steel Coils — combining long lifespan, corrosion resistance, and superior cost performance for your next project.
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