Spangle is the grainy appearance on galvanized steel. It is formed when liquid zinc cools and solidifies during hot dip galvanizing. Full sequins look like snowflakes or six-pointed stars. Its size, brightness and morphology depend on a range of factors, such as the composition of the zinc layer, the cooling method, etc.

When the zinc liquid is close to the solidification temperature, spray water droplets with a diameter of less than 0.1mm on the surface of the galvanized sheet immediately. It will then form small, uniform nuclei, which will help in the formation of small sequins. It is then temper-rolled with a reduction of less than 1% to obtain smooth sequins. The smallest sequins are good for painting, and the smooth ones are good for deep drawing.

The shape of the spangles depends on the type of alloy added to the zinc solution. For example, adding lead and antimony creates a phoenix-shaped sequin. And adding lead and tin produces fern-shaped sequins, etc.

In fact, spangles only provide a different surface appearance but do not affect the quality of the zinc coating. However, as the base metal of PPGI, sequins can affect its paint adhesion and corrosion resistance. Therefore, small or zero-sequin products are more suitable for the home appliance and automotive industries. Whereas regular spangle galvanized steel is commonly used in general-purpose and construction industries.

Zero spangles galvanized steel coil products mainly refer to special production processes, generally controlling lead to a certain level in the zinc pot, or special treatment after the steel coil is out of the zinc pot, such as the treatment of small spangles. The method of spraying zinc powder to control the spangle to less than a certain level can get zero spangle galvanized steel coil products. Compared to zero spangle galvanized coils, regular/big spangle galvanized coils are more susceptible to corrosion.