This method dips the iron or steel into molten zinc, which bonds with the surface and forms a protective layer. It involves the following steps:
Cleaning: This is to remove all forms of oil and dirt with a caustic solution.
Pickling: This next step involves putting the metal into acid to remove rust.
Fluxing: Once pickling is done, the metal goes into a flux solution to stop it from oxidizing before dipping.
Dipping: The steel is then dipped into a molten zinc bath until the temperature is the same as the bath, which is around 450°C.
Cooling: The material is then removed and allowed to cool, typically in air, solidifying the coating. (Quenching in water is sometimes used but is not the standard step; cooling is.)
This process creates a metallurgical zinc-iron alloy layer bonded to the steel, covered by an outer layer of pure zinc which, as it solidifies, can develop a shiny, snowflake look called a spangle.
