Patent ID: 9487852
Filing Date: 2016-11-08
CPC Classification: C22C,C23C

Claim Text:
1. A manufacturing method of a galvanized steel sheet, the manufacturing method comprising: circulating a coating bath which is a molten metal including a molten zinc and a molten aluminum in order of a coating tub, a separating tub, and an adjusting tub; coating a steel sheet which is dipped in the coating bath at the coating tub in which the coating bath transferred from the adjusting tub is stored at a predetermined bath temperature T separating by a flotation a top-dross which is precipitated at the separating tub in which the coating bath transferred from the coating tub to the separating tub is stored at a bath temperature T dissolving a residual dross at the adjusting tub in which the coating bath transferred from a lower part of the separating tub is stored at a bath temperature T decreasing a temperature of the coating bath of the separating tub to a temperature lower than a temperature of the coating bath of the coating tub, thereby preventing a formation of bottom-dross, and removing top-dross separated by the flotation, wherein an aluminum concentration in the coating bath of the separating tub is more than 0.14% by mass, wherein an aluminum concentration in the coating bath of the coating tub is 0.15% to 0.25% by mass, and wherein a first zinc-included-metal which includes an aluminum with a concentration higher than the aluminum concentration of the coating bath in the coating tub is supplied to the adjusting tub and is not supplied to the separating tub.