Difference Between Galvalume Sheet and Galvanized Sheet

The main difference between the galvanized steel coil and Galvalume steel coil is the different surface coatings.Galvanized sheets are uniformly plated with a zinc layer on its surface, which plays a role in anode protecting the base metal. That means an alternative corrosion onto the zinc layer takes the protection function for the base metal.  Only when all the zinc layer wholly corroded, then could damage the base metal inside. 

Galvalume surface coating was composed of 55% aluminum, 43.5% zinc and small amounts of other elements. In micro-structure view, the Zinc-Aluminum layer is in a “honeycomb” structure made of aluminum, where zinc was inclusively wrapped in. In this case, although the zinc-aluminum plays an anode protective role, due to the reduced zinc content, on the other hand, as the zinc material was wrapped in the aluminum “honeycomb” structure, which leads zinc is hard to be electrolyzed, so the anode protection is greatly reduced. Therefore, once Galvalume sheet is cut, the cut edge will soon be corrupted. It should be as little cut as possible. But if it has to be cut for application, the cutting edge should use corrosion-resistance paint and zinc rich paint to protect it to be able to extend the service life of the plate.

Galvalume steel coil surface is more beautiful than galvanized sheet, Galvalume price while expensive than galvanized sheet. And small spangle is more expensive than large spangle.

In the air damp rain and more area, once the galvalume sheet of a certain point of rust if not timely take measures, then, slowly rusty will eventually be diffused and even to the entire sheet; Galvanized sheet even if a point of rust will not spread.