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Aluzinc steel refers to steel coated with a 55% aluminum-zinc alloy, also known as 55% Al-Zn coated steel. GL steel is well suited for roofing and wall panels, as well as automotive, appliance, and furniture applications. With its versatility, durability, and attractive appearance, Aluzinc steel is widely preferred. Coating specifications range from AZ30 to AZ150, with thicknesses from 0.12 to 2.0 mm and widths up to 1500 mm. We also provide processing services including cut-to-length, slitting, and profile forming.
What Is Aluzinc Steel?
Aluzinc steel is similar to galvanized steel. It uses cold-rolled steel sheet as the substrate and is coated at approximately 600°C with an alloy coating composed of 55% aluminum, 43.4% zinc, and 1.6% silicon. The primary purpose of the Al-Zn coating is to protect the steel from oxidation. Due to the protective effect of aluminum, Aluzinc steel has stronger resistance to rust and corrosion.
If Aluzinc steel and galvanized steel have the same coating thickness, Aluzinc steel will have a longer service life under the same environmental conditions. The commonly used manufacturing process is known as the hot-dip coating process. Let’s take a step-by-step look at how it works.
Pretreatment
The pretreatment system removes contaminants from the surface of the substrate. This process usually includes degreasing, rinsing, pickling, and other treatments.
Hot-Dip Aluzinc Coating Process
After passing through the annealing furnace, the steel sheet is immersed in an aluminum-zinc bath. An air knife then removes excess coating to maintain the required coating thickness.
Inspection and Coiling
The coated steel sheet passes through a quality control system and is then coiled for sale.
Therefore, the structure of Aluzinc steel consists of:
- Substrate (cold-rolled steel sheet)
- Al-Zn coating (top and bottom surfaces)
Aluzinc Steel Specifications
| Chinese Code | European Code | American Code | Japanese Code |
| DC51D+AZ | DX51D+AZ | CS type B, type C | SGLCC |
| DC52D+AZ | DX52D+AZ | DS | SGLCD |
| S250GD+AZ | S250GD+AZ | 255 | – |
| S300GD+AZ | – | – | – |
| S350GD+AZ | S350GD+AZ | 345 Class1 | SGLC490 |
| S550GD+AZ | S550GD+AZ | 550 | SGLC570 |
What Color Is Aluzinc Steel Sheet?
Bare Aluzinc steel sheet has a silvery-white color with a regular spangled pattern. It is not as bright and glossy as galvanized steel sheet, but its surface is smoother.
Product Specifications
| Item | Galvalume Steel coil/sheet/strip |
| Material | DX51D+AZ, DX52D+AZ, DX53D+AZ, S220GD-S550GD |
| Standard | GB, JIS, ASTM, EN |
| Al-Zn Coating | AZ30-AZ150 |
| Thickness | 0.12 mm-2.0 mm |
| Width | ≤ 1500 mm |
| Coil Weight | 3-8 tons or as per your requirements |
| Surface treatment | Spray painting, fingerprint resistance, oiling, passivation, lamination, etc. |
| Aluminum Content | 55% |
| Package | Standard Export Package |
Which Is Better: Galvanized Steel or Aluzinc Steel?
In terms of corrosion resistance, Aluzinc steel offers better resistance than galvanized steel. GI and GL steel are very similar. Both are coated to protect the base metal from rust. The coating can extend the service life of the steel sheet by decades compared with uncoated metal.
The main difference between Aluzinc steel sheet and galvanized steel sheet lies in the composition of their coatings. Aluzinc steel sheet has an aluminum-zinc alloy coating consisting of 55% aluminum, 43.5% zinc, and 1.5% silicon, while the coating on galvanized steel sheet is primarily zinc.
Because aluminum is added to Aluzinc steel, and aluminum has 2–6 times the corrosion resistance of zinc, Aluzinc steel has significantly better corrosion resistance than galvanized steel.
In addition, Aluzinc steel offers better heat resistance and higher heat reflectivity than galvanized steel.
It should be noted that if Aluzinc steel needs to be painted, the available color options may be limited, as the color range for Aluzinc steel is not extensive.
However, in terms of price, Aluzinc steel sheets are more expensive than galvanized steel sheets.
Galvanized Steel vs. Aluzinc Steel Prices
Generally, Aluzinc steel is more expensive. For example, Aluzinc steel with an AZ50 coating is more expensive than galvanized steel with a G50 coating when the other specifications are the same. However, GL steel also has a longer service life. In addition, prices are affected by other factors, such as thickness, width, and packaging, and the two products are suitable for different environments.
Ga / 26 Ga / 29 Ga Aluzinc Steel Sheets
Ga (gauge) is commonly used to describe the thickness of metal sheets or wires. Generally, the higher the gauge number, the thinner the sheet. For example, 24-gauge Aluzinc steel sheet is approximately 0.7 mm thick; 26-gauge Aluzinc steel sheet is approximately 0.55 mm thick; and 29-gauge Aluzinc steel sheet is approximately 0.45 mm thick. You can refer to the specification table below.
| Materials | Stainless Steel | GI/GL | Aluminum |
| Gauge | inches (mm) | inches (mm) | inches (mm) |
| 30 | 0.0125 (0.33) | 0.0157 (0.40) | 0.0100 (0.25) |
| 29 | 0.0141 (0.36) | 0.0172 (0.44) | 0.0113 (0.29) |
| 28 | 0.0156 (0.41) | 0.0187 (0.47) | 0.0126 (0.32) |
| 27 | 0.0172 (0.43) | 0.0202 (0.51) | 0.0142 (0.36) |
| 26 | 0.0187 (0.48) | 0.0217 (0.55) | 0.0159 (0.40) |
| 25 | 0.0219 (0.56) | 0.0247 (0.63) | 0.0179 (0.46) |
| 24 | 0.025 (0.64) | 0.0276 (0.70) | 0.0201 (0.51) |
| 23 | 0.0281 (0.71) | 0.0306 (0.78) | 0.0226 (0.58) |
| 22 | 0.0312 (0.79) | 0.0336 (0.85) | 0.0253 (0.64) |
| 21 | 0.0344 (0.86) | 0.0366 (0.93) | 0.0285 (0.71) |
| 20 | 0.0375 (0.95) | 0.0396 (1.01) | 0.0320 (0.81) |
| 19 | 0.0437 (1.1) | 0.0456 (1.16) | 0.0359 (0.91) |
| 18 | 0.0500 (1.27) | 0.0516 (1.31) | 0.0403 (1.02) |
| 17 | 0.0562 (1.4) | 0.0575 (1.46) | 0.0453 (1.1) |
| 16 | 0.0625 (1.59) | 0.0635 (1.61) | 0.0508 (1.29) |
| 15 | 0.0703 (1.8) | 0.0710 (1.80) | 0.0571 (1.4) |
| 14 | 0.0781 (1.98) | 0.0785 (1.99) | 0.0641 (1.63) |
| 13 | 0.094 (2.4) | 0.0934 (2.37) | 0.072 (1.8) |
| 12 | 0.1094 (2.78) | 0.1084 (2.75) | 0.0808 (2.05) |
| 11 | 0.1250 (3.18) | 0.1233 (3.13) | 0.0907 (2.30) |
| 10 | 0.1406 (3.57) | 0.1382 (3.51) | 0.1019 (2.59) |
| 9 | 0.1563 (3.97) | 0.1532 (3.89) | 0.1144 (2.91) |
| 8 | 0.1719 (4.37) | 0.1681 (4.27) | 0.1285 (3.26) |
How Long Does Aluzinc Steel Last?
Aluzinc steel sheets have an expected service life of approximately 40–60 years. In practice, their service life mainly depends on the thickness of the Al-Zn coating and the service environment. If Aluzinc roofing is installed under suitable conditions, it can last for several decades.
Does Aluzinc Metal Rust?
Aluzinc steel has excellent corrosion resistance. However, Aluzinc steel is still a type of steel, so it will eventually rust if its protective coating is damaged. Rusting often starts at cut edges. Because the Al-Zn coating contains less zinc, its sacrificial anodic protection is weaker. When corrosion occurs at a specific point on a GL sheet, the rusted area may gradually spread across the surface.
Can Aluzinc Steel Be Painted?
Of course. The Al-Zn coating has excellent paint adhesion, making it easy to paint. Like PPGL steel, it can be painted in different colors for decorative or aesthetic purposes.
Aluzinc Steel Price
By comparison, Aluzinc steel sheets are more expensive than galvanized steel sheets due to their excellent properties. In addition, there are fewer manufacturers producing Aluzinc steel sheets. Generally, prices start at around US$800 per ton. In recent months, the price of Aluzinc steel coils has continued to rise.
Advantages of Aluzinc Steel Coils
Excellent Corrosion Resistance
Corrosion resistance is one of the main advantages of Aluzinc steel sheets. The aluminum-zinc coating on the surface protects the base metal. When the coating surface is damaged, the aluminum-zinc alloy layer forms a dense aluminum oxide layer that helps prevent further corrosion of the base metal.
Studies have shown that GL steel can have a service life up to three times that of GI steel. This is why GL steel is widely preferred for use in harsh environments.
Excellent Weather Resistance
Aluzinc steel sheets have excellent weather resistance and can withstand atmospheric pollution, severe weather conditions, ultraviolet radiation, and other environmental factors. They can maintain stable long-term performance even under these climatic conditions.
Excellent Heat Resistance
Aluzinc steel has excellent heat resistance and is not prone to oxidation at high temperatures. It can withstand temperatures above 300°C and is commonly used for chimney ducts, oven lighting, and light fixtures.
High Heat Reflectivity
GL steel has twice the heat reflectivity of galvanized steel and is therefore often used as a thermal insulation material. As a result, it is a better choice for roofing in hot climates.
Attractive Appearance
GL steel has a smooth surface with a spangled finish, giving it an attractive appearance. Therefore, it can be used directly without painting.
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