What is Galvalume?

Protecting steel from oxidation is a must for many projects. While applying a zinc coating to (known as galvanizing) steel is one common method to prevent corrosion, another material type, known as Galvalume, may also be a suitable option. But what is Galvalume?

What is Galvalume?

Galvalume is a coating consisting of zinc, aluminum and silicon that is used to protect a metal (primarily steel) from oxidation. It is similar to galvanizing in that it is a sacrificial metal coating which protects the base metal.

What is Galvalume Used For?

Galvalume is primarily used to protect iron-based alloys that are prone to rust. Galvalume-coated steel is better able to resist oxidation than plain carbon steel because the zinc and aluminum protect the underlying steel from the environment. The zinc also will more readily oxidize than the steel it contacts. This is similar to galvanized steel.

What is the Difference Between Galvanizing and Galvalume?

The main difference between galvanizing and Galvalume is that galvalume is a combination of zinc, aluminum, and silicon, while galvanizing is 100% zinc. The makeup of the three elements in a Galvalume coating is just over 50% aluminum, just under 50% zinc, with trace amounts of silicon.

An advantage that Galvalume has over normal galvanized material is that it has enhanced protection abilities. Over time, Galvalume tends to perform better than galvanized steel, especially when exposed to water or other liquids that can speed up the oxidation process. Even after a few decades, Galvalume-coated steel will be less likely to rust than normal galvanized steel.

Galvalume is also considered more aesthetically pleasing than hot-dipped galvanized materials.

Galvalume Thicknesses

Galvalume is applied to a material using the hot-dipping process. Therefore, a Galvalume coating has similar thicknesses to that of hot-dipped galvanized material. The thickness for the hot-dipping process is around 1 mil thick. The thickness can range somewhat depending on the coating specification. If the coating thicknesses of a Galvalume-coated steel and a galvanized steel are equal, the Galvalume steel will generally outlast the galvanized one, depending on the environment.

What Type of Metal Is Galvalume?

Galvalume coating is most commonly applied to carbon steel. However, most materials that can be galvanized can also be coated with Galvalume. Some additional metal types include:

• Cast Iron
• Ferritic Stainless Steel
• Martensitic Stainless Steel
• Low Alloy Steels

When is Galvalume Used?

One of the most popular applications of Galvalume steel is for outdoor metal paneling and roofing. Galvalume is used because it has superior resistance to corrosion in outdoor environments than standard galvanized steel. It is able to resist corrosion when exposed to snow, ice, and rain.

When Should Galvalume Not Be Used?

Galvalume should not be used in alkaline environments. The aluminum in Galvalume does not hold up well to that type of environment, so galvanized steel may be a better choice in that instance. Also, Galvalume does not do well if it is damaged. If the panel will be subject to scratches and indentation, then galvanized steel may be better suited as the material for the application. Even fastener installation may be enough to damage the Galvalume coating.