To prepare a brazing sheet made of Al alloy, suitable for heat exchanger, etc., and excellent in corrosion resistance, by providing an intermediate layer between a brazing filler metal and a core material in order to prevent the diffusion of mutual elements between them and also specifying an alloy composition, a thickness, and a cladding rate of the intermediate layer, respectively.
In a sheet for a heat exchanger, for constituting a tank part and a refrigerant passage by being press-formed and joined by means of vacuum brazing, an Al alloy core material 5 has a composition consisting of, by mass, 0.5-2.0% Mn, 0.1-1.0% Cu, 0.05-0.5% Mg, 0-0.3% Ti, and the balance Al. Both sides of the core material 5 are clad with Al-Si-Mg alloy brazing filler metals 3, 3', respectively, at a cladding rate of 5-20% per side. Further, an intermediate layer 4, which is composed of an Al alloy having a composition consisting of 0.5-2.0% Mn, 0.05-0.5% Mg, 0-0.3% Ti, further either or both of 0.05-0.5% Sn and 0.05-10.0% Zn, and the balance Al and also has ≥30μm thickness and ≤35% cladding rate, is formed between the brazing filler metal 3, on the side corresponding to the outer side of the tank part and refrigerant passage of a heat exchanger, and the core material 5.
SOGA NOBORU
KANO HIROSHI
MIYAJI HARUHIKO
TORIGOE EIICHI
DENSO CORP