Preparation method of spangle-free hot galvanized plate

The invention relates to the technical field of production of hot-dip galvanized steel plates, in particular to a preparation method of a spangle-free hot-dip galvanized plate. The method comprises the following steps: (1) uncoiling a cold and hard coil steel plate, and degreasing and cleaning after welding; (2) performing continuous annealing after degreasing and cleaning; (3) the annealed strip steel enters a zinc pot, the temperature of hot-dip galvanizing liquid is 480-520 DEG C, and the hot-dip time is 5-10 s; and (4) a gas injection forced cooling method is adopted for rapidly cooling the sample subjected to hot dipping, the cooling speed is larger than or equal to 30 DEG C/s, the cooling time is 10-15 s, the high-span temperature is smaller than or equal to 230 DEG C, and the temperature in a water dipping tank is smaller than or equal to 90 DEG C. According to the spangle-free hot-dip galvanized plate, the surface of a plating layer is smooth and clean, the surface is free of any macroscopic defects,