This is a process in which a protective coating of zinc and iron-zinc alloys is applied to steel by dipping into a bath of molten zinc. Most sheet steel is done on a continuous galvanizing line.
Regular spangle is coated on continuous lines to specific coating designations. During normal solidifications, regular spangles are the result of the unrestricted growth of zinc crystals.
Minimized spangle is the result of treating regular galvanized sheet during the zinc solidification to restrict the normal spangle formation. Product usually has a dull appearance not characterized by a high degree of uniformity and dissimilarity from coil to coil is not unusual.
Extra smooth is the result of skin passing coated galvanized sheet material to impart a higher degree of smoothness. It is usually supplied in a coating designation G-90 only and is used for exposed, critical surfaces that are to be painted. If fluting or stretcher strains are a hazard, extra smooth should be specified.