Galvanized and Aluminized Steel Sheets
Galvanized Steel Sheet
A galvanized sheet is a steel sheet coated with a layer of metallic zinc to prevent corrosion and extend its service life. This protective zinc coating is what gives the steel its characteristic resistance to rust.
AluminizedSteel Sheet
Also known as aluminized or hot-dip aluminized steel sheet, this material consists of a steel sheet coated with an aluminum-silicon alloy (90% aluminum and 10% silicon). The aluminized steel sheet offers superior heat resistance, reflectivity, and corrosion resistance compared to cold-rolled steel. It is widely used in various applications, including car mufflers and household appliances.
Properties of AluminizedSteel Sheet
High Temperature Resistance
Due to the unique combination of steel and aluminum in the coating, an iron-aluminum alloy forms, providing excellent high-temperature resistance. At 450°C, the aluminum coating retains high reflectivity. Even at temperatures up to 650°C, the protective layer remains intact without peeling, ensuring the steel plate is protected from oxidation.
Heat Reflectivity
At 480°C, the aluminum coating can reflect 80% of incoming heat, making it an efficient thermal insulation barrier or heat reflector. This property is especially useful in high-temperature applications where rapid heat reflection is necessary.
Mechanical Strength
At room temperature, the aluminized steel sheet has the same mechanical strength as its base material. At 480°C, the strength is ten times that of the aluminum coating, allowing for a reduction in steel plate thickness by at least 30%.
Corrosion Resistance
During the hot-dip coating process, molten aluminum reacts with oxygen to form a stable Al₂O₃ protective layer. This layer is resistant to water and is self-healing, even if the steel plate is scratched. As a result, the aluminized steel exhibits excellent resistance to chemical corrosion.
Ecological Benefits
Aluminum-coated sheets, when not chemically passivated, are safe for human health and can be used in food processing. They are fully recyclable, making them an eco-friendly material. Compared to stainless steel, aluminized sheets offer similar performance at about one-third of the cost.
Applications
Aluminum-coated steel sheets are used in a variety of industries, including:
- Automotive: Mufflers, exhaust pipes, and fuel tanks.
- Industrial Equipment: Combustion furnaces, heat exchangers, dryers, and air conditioners.
- Household Appliances: Water heaters, gas stoves, bread boxes, chimneys, microwave ovens, food processing machinery, electric ovens, and cookers.
- Building Materials: Roof coverings, wall panels, ceilings, and insulation components.
