提供一种在还原炉和还原炉中控制露点的方法，其中即使在镀锌的Si添加钢的情况下，也可以确保涂层的粘附性，可以在不增加合金化温度的情况下进行合金化处理，以及 可以获得具有优异涂层外观的热浸镀锌钢板。 当使用包括至少辐射管式还原炉的连续热浸镀锌设备对钢板进行退火和热浸镀锌处理时，通过具有水的加湿装置将干燥气体和加湿气体的混合气体 透气膜用作供给到还原炉中的气体。 将混合气体供给到还原炉中，从而控制还原炉中的露点。

Si even-added steel (鋼) securing the coating adhesion, and without the excessive raise the alloying temperature to alloying treatment, the plating appearance is excellent molten zinc to obtain a coated steel sheet, the dew point of the reducing furnace (露点) control method and reduced to provide a. At least a reduction in a continuous hot-dip galvanizing equipment having as a Radiant tube (爐) when subjected to annealing and hot-dip galvanizing treatment to the steel sheet, by a gas supplied to the reducing furnace, humidification by the humidifying device having the water vapor permeable membrane It controls the dew point in the furnace reduced by using a gas mixture of gas and drying gas, fed into the mixed gas to the reduction reactor.