BOTTOM DROSS REMOVING METHOD FOR MOLTEN Al-ZN ALLOY PLATING BATH, AND METHOD FOR MANUFACTURING MOLTEN Al-ZN ALLOY PLATED STEEL SHEET

摘要

PROBLEM TO BE SOLVED: To provide a bottom dross removing method for a molten Al-Zn alloy plating bath, more easily removable of bottom dross accumulated and solidified on the bath bottom of GL plating bath than in the past, and a method for manufacturing a molten Al-Zn alloy plated steel sheet by use of the bottom dross removing method.;SOLUTION: The bottom dross removing method for a molten Al-Zn alloy plating bath includes a first step of transforming, when removing bottom dross in a plating bath to be used for manufacturing the molten Al-Zn alloy plated steel sheet, the bath containing 50 mass% or more and 60 mass% or less of Al, the bottom dross so that 20% or more of an intermetallic compound of monoclinic crystal structure is contained by changing the composition of the plating bath; and a second step of removing the bottom dross from the plating bath successively to the first step. The method for manufacturing the molten Al-Zn alloy plated steel sheet includes steps of removing bottom dross by use of the method; and adjusting, after the step, the composition of the plating bath.;COPYRIGHT: (C)2012,JPO&INPIT