Corrosion resistant clad aluminum alloy brazing stock

In an automotive air conditioner evaporator formed from an aluminum alloy brazing stock material, as recited in claim 6, said aluminum alloy core layer being characterized by a tensile strength of about twenty thousand pounds per square inch and a yield strength of about nine thousand pounds per square inch.

In the method for forming an automotive air conditioner evaporator comprising complementary tubeplate members where said tubeplate members are respectively stamped at ambient temperatures from an aluminum alloy brazing sheet stock material and corresponding members brazed together in vacuum, said aluminum alloy brazing stock material comprising an aluminum alloy core layer which is clad on at least one surface with an aluminum-silicon brazing alloy;

• the improvement wherein said aluminum alloy core layer consists essentially of the following by weight, about 0.4 to about 0.5 percent copper, about 0.5 to about 0.9 percent manganese, about 0.2 to about 0.4 percent iron, up to about 0.2 percent silicon, up to about 0.05 percent titanium, about 0.2 to about 0.6 weight percent magnesium, and the balance being substantially all aluminum with trace amounts of ordinarily present elements;
• such that the aluminum alloy brazing stock material containing said aluminum alloy core layer is sufficiently ductile to be readily stamped at room temperature and brazeable in vacuum so as to form the air conditioner evaporator, and said elements within said aluminum alloy core layer sufficiently cooperate together so as to provide enhanced corrosion resistance of said aluminum alloy core layer relative to the environment and relative to said aluminum-silicon brazing alloy.