MANUFACTURE OF SUPPORT ROLL-LESS HOT DIP GALVANIZED STEEL SHEET

PURPOSE:To correct the shape of a steel sheet in the width direction, to prevent the stickup of dross and to manufacture a galvanized steel sheet having good appearance by spraying molten zinc to the steel sheet directly in the width direction at the standing up part from a hot dip galvanizing bath. CONSTITUTION:The steel sheet 1 is introduced into the hot dip galvanizing bath 3 and turned over the direction with a pot roll 2 and vertically drawn upward and N2 or Ar gas is blown from a wiping nozzle 6 to remove the excess plating zinc. In the manufacturing method for support roll-less galvanized steel sheet preventing slipping flaw, dross biting flaw, etc., at the standing-up part from the hot dip galvanizing bath, the molten zinc is sprayed directly in the width direction of the drawn-up steel sheet 1 from a zinc discharging hole 5 through a discharging pump 4. Then, the zinc discharging quantity is made to be adjustable and the discharging hole 5 is desirable to be possible to shift in the width direction according to the variation of the sheet width by adding a sheet width detecting function. By this method, the shape of the steel sheet 1 in the width direction is corrected and the stickup of the dross can be prevented.