AZ steel refers to hot-dip galvalume steel with a 55% aluminum, 43.5% zinc, and 1.5% silicon alloy coating, where "AZ" stands for Aluminum-Zinc. The numbers (AZ50, AZ150, AZ200) denote the total double-sided coating weight in g/m², determining corrosion resistance, durability, and cost-core metrics for construction, roofing, and industrial applications. As a leading supplier, GNEE STEEL provides premium AZ-coated steel coils/sheets with precise coating weights, strict quality control, and competitive pricing for global buyers.
What Is AZ Coating?
AZ coating (galvalume coating) is a hot-dip aluminum-zinc alloy layer applied continuously to steel substrates (cold-rolled or hot-rolled). Its fixed chemical composition delivers dual benefits:
- 55% Aluminum: Provides exceptional long-term corrosion resistance, heat reflectivity, and high-temperature stability (up to 315°C).
- 43.5% Zinc: Offers sacrificial protection for cut edges, scratches, and gaps-critical for fabrication.
- 1.5% Silicon: Prevents alloy fragmentation, ensures uniform coating adhesion, and enhances processability.
This combination makes AZ steel 3–5 times more corrosion-resistant than regular galvanized (Z-coated) steel, with a smooth, silvery spangle finish ideal for exposed applications.
Understanding AZ Coating Weights: AZ50, AZ150, AZ200
The number in AZ grades (50/150/200) represents the minimum total double-sided coating weight (g/m²) per ASTM A792 or GB/T 14978 standards. Below is a professional comparison table of key specifications and applications:
| AZ Grade | Double-Sided Coating Weight (g/m², Min) | Single-Sided Thickness (μm, Min) | Typical Applications | Core Benefits |
|---|---|---|---|---|
| AZ50 | 50 | 8 | Indoor panels, light framing, non-corrosive environments | Lightweight, low cost, easy fabrication |
| AZ150 | 150 | 20 | Roofing, wall cladding, agricultural buildings, general construction | Balanced corrosion resistance & cost (most popular) |
| AZ200 | 200 | 27 | Coastal areas, chemical plants, heavy industrial sites, extreme corrosion environments | Maximum durability, 25+ year service life |
-
Key Notes on Coating Weight:
Higher AZ number = Thicker coating = Better corrosion resistance = Higher cost.
AZ150 is the industry standard for outdoor construction-equivalent to Z275 galvanized steel in corrosion resistance but lighter (lower density of Al-Zn alloy: 3.72 g/cm³ vs. 7.12 g/cm³ for Zn).
All GNEE STEEL AZ products undergo 3-point testing to guarantee coating weight uniformity (per GB/T 14978).
Key Advantages of AZ-Coated Steel
Superior Corrosion Resistance: 3–5x longer life than galvanized steel; aluminum forms a dense oxide layer to block moisture/chemicals.
High Heat Reflectivity: Reflects 70%+ of solar radiation (2x higher than galvanized steel), reducing building energy costs.
Excellent Processability: Supports cutting, bending, stamping, and welding without coating peeling.
Cost-Effectiveness: Lighter weight than galvanized steel at the same coating thickness, lowering transportation and material costs.
Versatile Applications: Suitable for roofing, wall panels, gutters, industrial enclosures, and agricultural equipment.
Aluzinc Coating Specification
| Coating Code | Total Coating Weight | Total Coating Thickness | Approx. Single Side Thickness(μm) | Applicable Standards |
| (g/m², both sides) | (μm, theoretical) | |||
| AZ50 | 50 | 13.16 | 6.58 | GB/T 14978, EN 10346, ASTM A792 |
| AZ70 | 70 | 18.42 | 9.21 | GB/T 14978, EN 10346, ASTM A792 |
| AZ100 | 100 | 26.32 | 13.16 | GB/T 14978, EN 10346, ASTM A792 |
| AZ150 | 150 | 39.47 | 19.74 | GB/T 14978, EN 10346, ASTM A792 |
| AZ180 | 180 | 47.37 | 23.68 | GB/T 14978, EN 10346, ASTM A792 |
| AZ200 | 200 | 52.63 | 26.32 | GB/T 14978, EN 10346, ASTM |
Frequently Asked Questions (FAQ)
1. What does "AZ" stand for in steel?
"AZ" denotes Aluminum-Zinc, referring to the 55% Al-43.5% Zn-1.5% Si alloy coating on galvalume steel.
2. What is the difference between AZ50, AZ150, and AZ200?
The numbers represent double-sided coating weight (g/m²). AZ50 (50 g/m²) for indoor use; AZ150 (150 g/m²) for standard outdoor construction; AZ200 (200 g/m²) for extreme corrosion environments.
3. Is AZ-coated steel better than galvanized steel?
Yes. AZ steel offers 3–5x better corrosion resistance, higher heat reflectivity, and longer service life (25+ years for AZ200) compared to galvanized steel.
4. What standards does GNEE STEEL AZ steel comply with?
Our AZ products meet ASTM A792, GB/T 14978, and AS 1397 standards, with strict 3-point coating weight testing.
5. Can I customize AZ coating weight or substrate grade?
Absolutely. GNEE STEEL offers custom coating weights (AZ50–AZ200) and substrates (DC51D+AZ, S280GD+AZ, G350) to match your project needs.
6. What is the typical lead time for AZ steel orders?
Standard orders (AZ150 coils/sheets) have a 7–15 day lead time. Custom specifications or large volumes may require 20–25 days. Contact us for exact scheduling.
