Hot galvanized steel sheet and galvanized sheet has two types: electric galvanized sheet. Hot galvanized sheet with wet method and dry method, lead and zinc, REDOX, etc. The primary difference between different hot galvanizing method in steel pickling after cleaning, with what method activation improve the quality of galvanized pipe body surface. Mainly used in production of dry and REDOX process, its characteristics are shown in table. The galvanized zinc layer surface is very smooth and dense and uniform organization; Has good mechanical properties and corrosion resistance; Zinc consumption by 60% ~ 75% lower than the hot dip galvanized. Electric galvanized in technology has certain complexity, but for single-sided coating, plating thickness of different internal and external surface double plating, and thin-walled tube galvanized shall be adopted.