ALUMINUM-CLAD MATERIAL FOR HEAT EXCHANGER AND ALUMINUM PIPE AND PLATE USING THE MATERIAL

摘要

PURPOSE:To prevent crevice corrosion of an aluminum alloy material by composing it from a core material layer made of an aluminum alloy containing Cu, a middle metal layer made of an aluminum alloy containing Zn and Cu and a brasing filler metal layer containing Zn and Cu. CONSTITUTION:An aluminum clad material C for heat exchangers consists of a core material layer 1 made of an aluminum alloy containing 0.2wt.% or less Cu, a middle metal layer 2 which is laid on the upside of the core material layer 1 and made of an aluminum alloy containing 1.5wt.% Zn and 0.2wt.% or less Cu, and a brasing filler metal layer 3 which is laid on the upside of the middle metal layer 2 and contains 1.5wt.% Zn and 0.05wt.% or less Cu. Thereby, even when Zn contained in the brasing filler metal layer 3 evaporates into outside air, the progress of corrosion in the direction of plate thickness can be delayed because the brasing filler metal layer 3 contains an enough amount of Zn for sacrificial corrosion effect and corrosion is of face corrosion.