MULTILAYER ALUMINIUM SHEET FOR FLUX-FREE HIGH TEMPERATURE BRAZING IN CONTROLLED ATMOSPHERE Russian patent published in 2018 - IPC B23K1/12 B23K35/28 B32B15/01 C22C21/02 C22C21/08 F28F21/08 

FIELD: metallurgy.

SUBSTANCE: multi-layer sheet for flux-free high temperature brazing comprises an aluminium alloy core coated with intermediate layer of aluminium alloy, and solder of aluminium alloy applied on the intermediate layer. The core is made of 3XXX aluminium alloy containing, wt %: Mn<2.0, Cu≤1.2, Fe≤1.0, Si≤1.0, Ti≤0.2, Mg≤2.5, Zr, Cr, V and/or Sc in total ≤0.2, the rest is Al and unavoidable impurities. The intermediate layer is made of aluminium alloy containing, wt %: Mg 0.2-2.5, Mn <2.0, Cu≤1.2, Fe≤1.0, Si≤1.0, Ti≤0.2, Zn≤6, Sn≤0.1, In≤0.1, Zr, Cr, V and/or Sc in total ≤0.2, the rest is Al and unavoidable impurities. The solder is made of an aluminium alloy containing, wt %: Si 5-14, Mg<0.02, Bi 0.05-0.2, Fe≤0.8, Zn≤6, Sn≤0.1, In≤0.1, Cu≤0.3, Mn≤0.15, Sr≤0.05, the rest is Al and unavoidable impurities. The core material and the intermediate layer have higher melting point than the solder, and the intermediate layer is protective relative to the core. The total thickness of the cladding layer consisting of the intermediate layer and solder layer with respect to total sheet thickness is 3-30%. Soldering can be carried out in inert or reducing atmosphere without necessity of for applying the flux.

EFFECT: possibility for soldering complex designs with corrosion potential.

16 cl, 2 tbl