When selecting steel for roofing, siding, construction, agricultural, and industrial applications, corrosion resistance and long-term durability are often major considerations. GALVALUME® steel is a coated steel product known for its combination of corrosion resistance, durability, heat reflectivity, and attractive appearance.
GALVALUME® is a registered trademark of BIEC International, Inc. and its licensed producers. The trademark refers to steel sheet coated with a 55% aluminum-zinc alloy. The generic description for this type of material is commonly referred to as 55% aluminum-zinc alloy-coated steel.
What Is GALVALUME® Steel?
GALVALUME® steel is carbon steel sheet coated with an aluminum-zinc-silicon alloy using a continuous hot-dip coating process. The coating is commonly composed of approximately 55% aluminum, 43% zinc, and 1–2% silicon, although exact chemistry can vary by product specification and producer.
During production, steel strip passes through a molten aluminum-zinc coating bath. The resulting metallic coating provides the underlying steel with enhanced resistance to atmospheric corrosion while maintaining the strength and formability characteristics of the steel substrate.
The technology was introduced in the early 1970s and has since become widely used in building and industrial applications.
How Does GALVALUME® Work?
The performance of GALVALUME® steel comes from the properties of its aluminum-zinc coating.
Aluminum provides strong corrosion resistance by forming a stable, protective oxide layer on the surface. Zinc, meanwhile, contributes sacrificial protection to exposed areas of the coating. The combination creates a coating system that can provide excellent long-term protection for the steel substrate.
The coating also has a distinctive microstructure consisting of aluminum-rich and zinc-rich phases. This structure contributes to the material's corrosion-resistant performance in many atmospheric environments.
Benefits of GALVALUME® Steel
Excellent Corrosion Resistance
One of the primary advantages of GALVALUME® steel is its resistance to atmospheric corrosion. The aluminum-rich coating provides a protective barrier while the zinc component contributes additional corrosion protection.
This makes 55% aluminum-zinc alloy-coated steel particularly useful where long service life and resistance to weather exposure are important considerations.
Long-Term Durability
GALVALUME® steel is frequently selected for applications where durability and extended service life are priorities. It can be used as bare coated steel or as a substrate for painted and other finished products.
Its combination of a steel substrate and corrosion-resistant coating provides a balance of strength and environmental resistance.
Heat Reflectivity
The aluminum component of the coating also gives GALVALUME® steel good heat-reflective properties. This can make it useful for exterior building applications where solar heat gain is a consideration.
Attractive Appearance
The coating has a distinctive metallic appearance that can be desirable in architectural and commercial applications. GALVALUME® steel can also be used as the substrate for prepainted steel products, providing additional options for color, appearance, and finishing.
Versatility
55% aluminum-zinc alloy-coated steel is used across a broad range of applications, including commercial and industrial buildings, roofing and siding, agricultural structures, appliances, gutters, automotive components, and other fabricated products.
GALVALUME® vs. Galvanized Steel
GALVALUME® and galvanized steel are both coated steel products, but they use different coating systems.
Galvanized steel is coated primarily with zinc. The zinc coating provides barrier protection as well as sacrificial protection when the surface is damaged.
GALVALUME® steel, by contrast, uses a coating containing approximately 55% aluminum, 43% zinc, and a small amount of silicon. The combination of aluminum and zinc provides a different corrosion-protection mechanism and makes the material particularly well suited to many exterior building applications.
The best choice depends on the environment, fabrication requirements, coating specification, appearance, cost, and intended service life of the finished product.
Common Applications for GALVALUME® Steel
GALVALUME® steel can be found in numerous commercial, industrial, construction, and manufacturing applications.
Common uses include:
- Commercial and industrial roofing
- Metal siding and wall panels
- Agricultural buildings
- Pre-engineered metal buildings
- Light-gauge framing
- Construction tubing
- Gutters and downspouts
- Appliances
- Outdoor cabinets and enclosures
- Selected automotive components
- Prepainted steel products
- Architectural applications
Its combination of corrosion resistance, formability, durability, and appearance makes it a versatile coated-steel option.
Understanding GALVALUME® Coating Specifications
When purchasing GALVALUME® or other aluminum-zinc-coated steel, buyers should look beyond the product name. Important considerations can include the steel grade, coating designation, coating weight, thickness, width, mechanical properties, surface finish, and applicable ASTM specification.
For example, ASTM A792 covers steel sheet coated by the hot-dip process with a 55% aluminum-zinc alloy. The specific requirements for a project should be reviewed with the steel supplier and compared with the applicable material specification.
A steel supplier can also help determine whether a particular coated-steel product is appropriate for forming, fabrication, roofing, siding, structural, or other applications.
Why Work With an Experienced Steel Supplier?
Selecting the right coated steel involves more than choosing a corrosion-resistant material. Factors such as steel grade, thickness, coating requirements, dimensions, fabrication processes, environmental exposure, and end use can all affect material selection.
An experienced steel supplier can help customers identify the appropriate product and specification for their application, source material from qualified mills, and provide services such as cutting, processing, slitting, or other value-added operations when available.
For manufacturers, fabricators, contractors, and construction companies, having a reliable source for coated steel can also help simplify purchasing and improve material availability.
Is GALVALUME® Steel Right for Your Application?
GALVALUME® steel has become a widely used coated-steel product because it combines the strength and versatility of steel with the corrosion-resistant characteristics of an aluminum-zinc coating.
Whether the application involves roofing, siding, agricultural buildings, commercial construction, appliances, or industrial fabrication, 55% aluminum-zinc alloy-coated steel can offer a compelling combination of durability, corrosion resistance, heat reflectivity, and appearance.
When comparing GALVALUME® with galvanized steel or other coated-steel products, consider the specific requirements of the application rather than relying on coating type alone. A knowledgeable steel supplier can help evaluate the material specification and determine which coated-steel product best fits the project's performance and fabrication requirements.
Trademark Notice: GALVALUME® is a registered trademark of BIEC International, Inc. and some of its licensed producers. The term refers to 55% aluminum-zinc alloy-coated steel products sold under the GALVALUME® trademark.