The main reasons for zinc layer shedding are: Surface oxidation, silicon compounds, cold bound emulsion is too dirty, NOF section oxidation atmosphere and protective gas dew point is too high, air fuel ratio is unreasonable, hydrogen flow rate is low, furnace aerobic infiltration, strip into the pot temperature is low, RWP section furnace pressure is low and door suction, NOF section furnace temperature is low, Grease evaporation is not enough, zinc pot aluminum content is low, unit speed is too fast, insufficient reduction, zinc liquid residence time is too short, coating thickness.