Hot-dip galvanized defects: off, scratch, plaque passivation, zinc tablets, the thick side, the marks of the air knife, air knife scratches, exposed steel, inclusions, mechanical damage, the bad performance of steel substrate, wave edge, buckling,substandard size, embossing, the zinc layer thickness of the sub-roller printing.

The main reasons of zinc coating off are: the surface oxide, silicon compounds, the cold rolling emulsion fluid is dirty, NOF oxidizing atmosphere and protect the gas dew point is too high, the air-fuel ratio unreasonable, the hydrogen flow is low, stove aerobics penetrate, strip wok temperature is low, the RWP segment low furnace pressure and door suction, NOF, furnace temperature low, oil evaporation is not the low aluminum content of the zinc pot, the unit too fast, not fully restore the zinc solution to stay time is too short, thick coating migraine.