Describe galvanizing process with suitable diagram.
It is the process of coating iron or steel sheets with a thin coat of zinc to prevent it from rusting.
Process: The iron or steel sheet to be galvanized is first cleaned with dilute H2SO4 to remove any oxide layer or impurities. It is then washed with water to remove acid completely. It is then passed through drier to dry it completely. Then it is dipped in a bath of ammonium chloride solution which helps in adhesion of the molten zinc particles to steel sheet . It is then dipped in a bath of molten zinc at 4250C to 4600C temperature and passed through series of rollers to remove excess zinc and in order to get uniform coating. Finally it is annealed at 6500C.