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MagnaGuard Steel Coil & Sheet Metal

Pre-Painted Aluminum-Zinc-Magnesium Carbon Steel


MagnaGuard is an alloy-coated carbon steel offering advanced protection for today's metal roofing and metal wall panel systems. Similar to Galvalume® but with the added strength of Magnesium, MagnaGuard features a coated layer of 55% aluminum, 43.4% zinc-magnesium and 1.6% silicone over carbon steel delivering improved resistance to corrosion in extreme environments and enhanced protection against failure from cuts and scratches. Available pre-painted with Fluropon® 70% PVDF with Kynar 500® in nearly 40 colors.

MagnaGuard from Metal Alliance meets or exceed ASTM A1046 requirements.


Grades: 50, 80 and CS-B

Coating Weight: ZM150

Thickness: 24ga

Finish: Pre-Painted PVDF w/ Kynar 500


  • Coil - 20”, 24” 

  • Flats - 4’ x 10’


  • Up to 25 years† on substrate

  • Up to 40 years† on coating


  • Improved resistance to corrosion from salt spray

  • Advanced protection at cut edges and scratches

  • High heat resistance

  • Outstanding coating adhesion

  • Excellent formability

  • Available in nearly 40 colors



Magnaguard Quick Reference Guide

†For warranty information, including detailed coverages and exclusions, contact a Metal Alliance representative. MagnaGuard™ is a registered trademark of Metal Alliance Supply LLC. Galvalume® is a registered trademark of BIEC International Inc. Fluropon® is a registered trademark of The Sherwin Williams Corporation. Kynar 500® is a registered trademark of Arkema Inc. 


How is MagnaGuard Different?

Each type of protective alloy has its own physical and mechanical properties, all with important factors in determining the longevity, strength, and overall performance of the coating. While Galvalume is a premium product with many advantages, it's protection of the underlying metal from corrosion is reduced at scratches and cut edges which can ultimately lead to premature substrate failure. AL-ZN coated steel is also not recommended in coastal environments since the sodium chloride in salt spray will prematurely break down the coating and compromise the underlying metal roof or wall system.

MagnaGuard offers all the protective properties of aluminum and zinc in prolonging the life of underlying steel. Adding magnesium to the formula works to intensify the beneficial effects of both zinc and aluminum at just the right time to produce a self-healing reaction that offers advanced protection of the substrate at cut edges and scratches.

Magnaguard Chemical Composition

Why is MagnaGuard Better?

Al-Zn coated steel, or Galvalume, is a protective alloy containing aluminum-rich areas in a zinc-rich matrix with trace amounts of silicone. MagnaGuard improves on this formula with the addition of two important magnesium compounds, Magnesium-Zinc (MgZn2)and Magnesium-Silicone (Mg2Si). Carefully positioned to enhance the corrosion protection properties of aluminum and zinc, MgZn2 is located near the top of the alloy coating, while Mg2Si is situated toward the base steel. 

As MagnaGuard is exposed to the elements, the zinc begins the sacrificial galvanic process of corroding first in favor of aluminum to protect underlying steel. As a thin oxidized film by-product of zinc corrosion develops, the presence of MgZn2 works to stablize this action making the corrosion product less permeable. This stabilizing reaction is accelerated when the steel becomes exposed at a cut edge or scratch as the oxidized film spreads more quickly in the exposed areas, creating an even more compact layer of protection. 

As zinc and MgZn2 are consumed by self- sacrificial corrosion, the scratches and cut edges are sealed off more efficiently. At the same time, Mg2Si particles closer to the substrate act as additional barriers both slowing corrosion and restricting corrosion pathways to the underlying steel substrate. As the barrier protection of aluminum is depleted more slowly, the result is prolonged protection of steel and longer-term performance of the metal panel system.

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