Galvalume® is a 55% aluminum–zinc alloy hot dipped metallic coated steel product. Galvalume® is a brand name (owned by BIEC International, Inc.), and a similar product is called Zincalume. The Galvalume® coating nominal composition is as follows: 55% aluminum, 1.6% silicon, balance zinc (approximately 43%). Therefore, some specifications may refer to Galvalume® as 55Al-Zn. Due to the combination of aluminum and zinc, Galvalume® affords both galvanic and barrier protection. Galvalume® is also more resistant to degradation at high temperatures than galvanize. Galvalume® can withstand up to 600 degrees Fahrenheit with out discoloration.
Galvalume® is commonly used for building panels and roofing applications as Structural Steel Grades 50 or 80. Other uses are agricultural buildings, appliances such as toasters, and fireplaces. Galvalume® is not recommended for harshly corrosive environments (such as proximity to sea water, exposure to long wet times, cold climates where overnight condensation is a regular condition, chronic corrosive chemical exposure, or animal confinement).
Galvalume® is available in CS, FS, DS (not DDS), and Structural Steel Grades 33, 37, 40, 50, and 80. Galvalume® coating is comparatively more brittle than galvanize coating; therefore it is uncommon to see FS and DS applications because of adhesion issues during forming. There is also a high temperature grade (HTS) available that resists changes in base metal properties at higher temperatures up to 1250F.
Galvalume® coating weights are designated with a prefix of AZ. Most common coating weights are AZ50 and AZ55, but it is also available as AZ35 and AZ60. As a general statement, AZ55 is normally used for bare applications and AZ50 is used for painted or acrylic coated applications. With regard to coating thickness, AZ50 Galvalume® coating is approximately as thick as G90 galvanize coating. Galvalume® can be ordered as Extra Smooth and as Tension Leveled. Any Prepaint items should be ordered as both Extra Smooth and Tension Leveled.
Galvalume® can be bare (with chem. treat and/or oiled), have an acrylic coating applied, or can be painted. The chem. treat used for Galvalume® is the same as that used for galvanized. Vanishing oil is used on Galvalume® rather than the standard oil that is applied to galvanize. Prepainted Galvalume® can be ordered chem. treat dry from the mill. This is opposite of galvanize which should be without chem. treat and oiled for prepainted applications. Acrylic coating is clear and is applied at the mill.
Acrylic is used in lieu of chem. treat and oil. The acrylic resin blocks oils (from hands), therefore making it less susceptible to finger printing. The acrylic coating also has a lubricity to it that allows for roll forming without additional lubrication. In fact, oiling over the acrylic coating can provide less lubricity than the acrylic coating without oil. Galvalume® with acrylic coating is seen under brand names such as Acrylume, Galvalume® Plus and GALVAL.
A warranty is offered by Galvalume® producers for AZ50 and AZ55. Some Galvalume® producers offer a warranty of 20 years 6 months against perforation (due to corrosion) on bare Galvalume® regardless of coating weight. Neither painting nor acrylic coating will increase the warranty from the mill. Painting must be applied by an approved coater using an approved paint. Paint manufacturers provide separate warranties specific to the paint. The warranty is only valid under normal exposure conditions and does not apply to corrosive environments or when design issues control the product life.
If you would like to inquire about our Galvalume® inventory please contact our Building Products Representatives at 1-800-830-3252.