Patent ID: 11571769

Abstract:
In a brazing sheet manufacturing method, a cladding slab is prepared by overlaying at least a core-material slab composed of an aluminum material and a filler-material slab composed of an Al—Si series alloy, in which a metal element that oxidizes more readily than Al is included in at least one of the slabs. A clad sheet is prepared by hot rolling this cladding slab, which then has at least a core material layer composed of the core-material slab and a filler material layer composed of the filler-material slab and disposed on at least one side of the core material. Then, a surface of the clad sheet is etched using a liquid etchant that contains an acid. Subsequently, the clad sheet is cold rolled to a desired thickness. In flux-free brazing, such a brazing sheet is capable of curtailing degradation in brazeability caused by fluctuations in dew point and oxygen concentration.