Galvanized steel coil is cold-rolled sheet that passes through molten zinc, bonding a protective layer to both surfaces. The zinc blocks moisture and sacrifices itself at cut edges and scratches, so the base steel resists rust. Standard coils run 0.12–6.0 mm thick, 600–1500 mm wide, 3–25 t per coil, with zinc coatings from Z30 to Z275 g/m². Thinner coatings suit indoor and dry service; heavier coatings suit roofing and coastal sites. Each coil should arrive with a mill certificate stating grade, coating mass, and mechanical properties.
