ASTM A653 covers both zinc-coated (galvanized) and zinc-iron alloy-coated (galvannealed) steel coils. The galvannealed coating is produced by reheating the galvanized steel to alloy the zinc coating with the iron substrate.The standard specifies different classes of coating weight, ranging from G30 to G235. These classes indicate the amount of zinc coating per unit area, with higher numbers representing thicker coatings.The standard covers several steel grades, such as CS (commercial steel), DDS (drawing quality steel), EDDS (extra deep drawing quality steel), SS (structural steel), and more. The selection of steel grade depends on the intended application and required mechanical properties.ASTM A653 defines various surface finishes, including regular spangle, minimized spangle, and zinc-iron alloy spangle (for galvannealed). The spangle refers to the visible crystalline structure that forms on the surface of the galvanized coating.The standard specifies the maximum allowable levels of elements such as carbon, manganese, phosphorus, sulfur, and others. These limits ensure the desired properties and quality of the galvanized steel.
