What is Al-Zn-Mg Steel Coil?

Aluminum-zinc-magnesium (Al-Zn-Mg) coated steel coil is a type of alloy-coated sheet material made by applying aluminum, magnesium, zinc, and other metals through advanced coating technologies.
Composition and Properties
The SuperDyma variant of Al-Zn-Mg coating incorporates additional elements such as aluminum, magnesium, and silicon into the traditional zinc coating. The combined effect of these elements significantly enhances corrosion resistance. Specifically, the addition of magnesium offers notable improvements over previous aluminum additions, while silicon not only improves the workability of the aluminum-containing coating but also enhances corrosion inhibition through its synergistic action with magnesium.
Corrosion Resistance Mechanism on Flat Surfaces
Al-Zn-Mg coated steel exhibits excellent anti-corrosion properties, making it suitable for harsh environments like large community substations, electrical cabinets, evaporative condensers, HVAC ducts, and automotive applications. These environments are often exposed to prolonged moisture and acidic or alkaline conditions, which ordinary galvanized or aluminum-zinc-coated steel cannot withstand as effectively. Al-Zn-Mg coated steel has a corrosion resistance up to 10-20 times greater than that of galvanized steel, withstanding 4500 hours of salt spray testing without red rust formation at a coating weight of 275 g/m². Moreover, since no post-coating or painting is required, costs are reduced, and delivery times are shortened. In alkaline or coastal environments, its corrosion resistance can rival that of stainless steel.
Corrosion Resistance Mechanism on Cut Edges and Welded Areas
Initially, red rust may appear on the cut edges of Al-Zn-Mg coated steel due to the exposure of the base metal. However, over time, protective layers composed primarily of zinc hydroxide, basic zinc chloride, and magnesium hydroxide form around the cut edges. These layers develop within a few months and provide a dense protective film that reduces conductivity and inhibits corrosion. Additionally, the silicon content in the coating promotes the formation of this protective layer. Therefore, Al-Zn-Mg coated steel has self-healing properties at cut edges and punched holes, preventing the spread of red rust.
Processing Performance
Al-Zn-Mg coated steel utilizes unique international production processes that ensure high plasticity and stable processing performance. It can be easily cut, bent, and stamped to meet various design requirements. This material can replace post-galvanizing treatments and even substitute stainless steel in certain industries.
Strength Grades
Al-Zn-Mg coated steel has yield strengths ranging from 235 MPa to 600 MPa, making it suitable for lightweight structural applications. Its coating density is very high, with a hardness of 135 HV, which is 2.5 times that of post-galvanized coatings (50 HV). This increased hardness enhances scratch resistance and surface smoothness.
Suitable Industries
Al-Zn-Mg coated steel is widely used in industries requiring high rust resistance, such as photovoltaic supports, corrugated pipe culverts, automotive parts, refrigeration equipment, livestock farming, construction, and sheet metal fabrication.