Method for manufacturing hot-dip galvanized steel sheet

A method for manufacturing a hot-dip galvanized steel sheet, the method comprising performing a hot-dip galvanizing treatment on a steel sheet containing Si in an amount of 0.2 mass % or more by using a continuous hot-dip galvanizing apparatus including an annealing furnace in which a heating zone, a soaking zone, and a cooling zone are arranged in this order, a snout adjacent to the cooling zone, and hot-dip galvanizing equipment,

• wherein a humidified nitrogen-hydrogen gas mixture containing moisture in such a manner that expression (1) below is satisfied is supplied into a region on the downstream side of the soaking zone,
• wherein gas nozzles are arranged over the entire perimeter of an inner wall of the snout, wherein nitrogen gas or a nitrogen-hydrogen gas mixture is supplied through the gas nozzles downward along the inner wall,
• wherein at least two exhaust ports are disposed in an upper part of the snout to discharge the gas that is supplied through the gas nozzles, and
• wherein the dew point in the snout is controlled to be −50° C. to −35° C.:
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• M
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• X
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• where M denotes the amount of moisture contained in the humidified gas that is supplied into the soaking zone and X denotes a parameter regarding an influence of a surface area of the steel sheet.