At present, hot-dip galvanized products mainly include steel plate, steel strip, steel wire, steel pipe, etc., of which hot-dip galvanized steel plate accounts for the largest proportion. For a long time, the hot-dip galvanizing process has been favored by people because of its low plating cost, excellent protection characteristics and beautiful appearance. It is widely used in the fields of automobile, construction, household appliances, chemical industry, machinery, petroleum, metallurgy, light industry, transportation, electric power, aviation and marine engineering.