A hot dip coating apparatus for coating a metal wire or strip with a molten metal. A bath of molten metal has at least one guide member immersed therein. A cooling chamber is positioned above the guide member and has, at the bottom thereof, a bore through which the wire passes and also has a cooling liquid in the bottom thereof. A liquid supplier is attached to the cooling chamber, and a liquid level control means in the form of a monitor coupled to the liquid supplier keeps the liquid at a predetermined liquid level. The guide member and the cooling chamber are combined in a unitary body. The wire coated with the molten metal is cooled by the cooling liquid while passing through the bore while being guided by the guide member.
In order to provide a hot-dip aluminized steel sheet with increased peeling resistance of the coating layer, the thickness of the Fe--Al--Si alloy-layer is set to be 1-5 .mu.m, while the maximum differential unevenness of thickness of the Fe--Al--Si alloy layer is set to be 0.5-5 .mu.m. The hot-dip aluminized steel sheet is manufactured by controlling an elapsed time from the beginning of immersion of the basemetal steel sheet into the aluminizing bath to the completion of solidification of the coating-metal layer which has passed through the bath. In addition another elapsed time is controlled from the time after the base-metal steel sheet has been guided out over the bath to the completion of solidification of the coating-metal layer.
A method and apparatus for cooling metal wire or strip being drawn vertically from a hot dip bath and between a pair of refractory wiping pads. The wire or strip passing between the wiping pads directly into a chamber containing a cooling liquid which is supported above and at least in part by the wiping pads. The chamber having inlet and outlet means for the cooling liquid and a removable wall to allow more rapid draining of the chamber and access to the inside of the chamber for changing the wiping pads and/or re-threading the wire.
