Inspect the coating of the steel and if it's soft and easily scratched, it's most likely galvanized.
Can the steel sheet be formed into intricate shapes without any loss in coating adhesion to the steel? If so, it's galvanized coating.
Is the coating on the steel sheet hard, brittle? Is there powdering when the sheet is formed in a way that causes high compressive strain? If so, it's galvannealed steel.
If the sheet metal has signs of reddish-colored corrosion, it has a galvannealed coating. This occurs because of the iron in the coating, which is not found in galvanized steel.
Is the sheet of steel painted? If so, it's probably galvannealed, as most galvannealed steel is painted thickly in order to slow down corrosion.
Things You Will Need
- If you're trying to decide whether you should use galvanized or galvannealed steel for a particular project, you will want to consider whether spot welding will be involved, whether it will be painted, and whether deep drawing will be involved.