A792

ASTM A792 is a coating for steel sheet that combines three metals: steel, aluminum and zinc. Manufacturers begin with a carbon steel base sheet that is then continuously hot-dipped with aluminum and zinc alloys to reach a coating consisting of 55% aluminum, 43.4% zinc and 1.6% silicon. This process enables one finished product to possess some of the top characteristics of each metal, which is why it has become one of the most popular choices in the panel and roofing market and can be used for a variety of other applications.

Yes, A792 is available in painted or unpainted coating weights, including AZ50, AZ55 and AZ60. The A stands for aluminum and the Z stands for zinc, indicating the aluminum-zinc alloy coating of A792. Please see Product Warranty chart above for complete details.

• AZ50 means that there are 0.50 ounces per square foot of aluminum-zinc alloy coating applied to the substrate. AZ50 is the standard coating weight for painted sheet and coil products.
• AZ55 is equal to 0.55 ounces per square foot of aluminum-zinc alloy coating applied to the substrate. AZ55 is the standard coating weight for bare or unpainted (often called acrylic-coated) sheet and coil products.
• AZ60 means that there are 0.60 ounces per square foot of aluminum-zinc alloy coating applied to the substrate. AZ60 offers a superior level of corrosion resistance, often used for projects that must withstand harsher environments.

Built on decades of expertise in galvanized sheet, Nucor’s A792 coated sheet delivers reliable performance across steel building markets. It is entirely produced by Nucor through every step from melting to coating for supply chain efficiency. Manufactured in Indiana and Arkansas, this American steel product offers excellent corrosion resistance, durability and a reliable warranty. Crafted sustainably with EAF steel, A792 provides a dependable, high-performance solution from a trusted source.

Yes, the technical specification of ASTM A792 is known to have “self-healing” properties due to its ability to prevent corrosion on cut edges and scratches on the steel. Rust is caused by oxygen bonding to the steel. Barrier-type coatings like oil and paint block this oxygen from bonding. The aluminum-zinc coating is considered a “sacrificial” coating that slows the oxygen bonding with the steel where the aluminum essentially sacrifices itself to slow down the process.

A792 is adaptable to various market requirements but is primarily used for steel roofing and siding, agricultural buildings, gutters and other steel building components. Its combination of flatness, corrosion resistance and heat reflectivity ensures durability across many industries and applications.

While A792 offers many benefits across the metal building market, it is generally not recommended for animal confinement buildings and coastal environments due to environmental factors. Contact a Nucor teammate for use case recommendations.

These two metal coatings applied to a steel core are similar, but differ in benefits and drawbacks, including durability and performance expectations.

• A792 is a sheet metal coating composed of 55% aluminum, 43.4% zinc and 1.6% silicon. It is offered bare, with an acrylic coating, or painted. It exhibits self-healing properties and is backed by a warranty.
• Galvanization (or galvanized coating) is when zinc is applied to steel substrate through a hot-dip process. Galvanized steel products are not as corrosion-resistant as products coated with A792.

Steel roofing provides benefits such as exceptional durability and longevity, resistance to extreme weather conditions like wind, fire and snow, low maintenance needs and energy efficiency due to its reflective qualities. When made with EAF steel, it is also sustainable and fully recyclable at the end of its long lifespan.

Metal roofs are made from up to 95% recycled materials when produced by an EAF steelmaker like Nucor, and they are 100% recyclable. Alternatively, asphalt shingles generate significant waste, with over 12 billion square feet ending up in landfills annually. Metal roofs also offer a responsible option because a roofer can install them directly over an existing roof, eliminating the debris associated with a traditional roof replacement.

Yes, metal roofs can save homeowners on energy costs, depending on where the home is geographically located. Areas with cooler temperatures typically achieve greater savings with unpainted metal roofs because they absorb more heat from the sun. In contrast, warmer areas might prefer pre-painted options, as they can re-emit up to 90% of solar radiation.

There is a common misconception that metal roofs are more vulnerable in extreme weather. However, metal roofs do not attract lightning during thunderstorms any more than asphalt roofs. Additionally, most metal roofs have a Class A fire rating, indicating resistance to surface flames. Therefore, these roofs are just as safe as asphalt shingles, even in regions prone to wildfires.

Metal building materials coated with A792 should not be used in the following areas or conditions:

• Livestock or animal facilities, due to increased corrosion from animal urine and ammonia gases
• If A792 comes in contact with certain materials (including concrete, bricks, copper, lead, iron and treated lumber) it can cause galvanic corrosion
• Coastal areas with high salt content
• Areas with high heat, strong alkaline or acidic conditions

Nucor’s A792 product is sheet steel having a coating comprising 55% aluminum, 43.4% zinc, and 1.6% silicon. GALVALUME® is advertised as 55% Al-Zn coated sheet steel. We invite you to compare Nucor’s A792 product to aluminum-zinc alloy coated sheet steel sold under the GALVALUME® trademark.