Abstract: The present invention provides extruded tubes for heat exchangers having improved corrosion resistance when used alone and when part of a brazed heat exchanger assembly with compatible finstock. The tubes are formed from a first aluminum alloy containing 0.4 to 1.1% by weight manganese, up to 0.01% by weight copper, up to 0.05% by weight zinc, up to 0.2% by weight iron, up to 0.2% by weight silicon, up to 0.01% by weight nickel, up to 0.05% by weight titanium and the balance aluminum and incidental impurities. The fins are formed from a second aluminum alloy containing 0.9 to 1.5% by weight manganese or an alloy of the AA3003 type, this second aluminum alloy further containing at least 0.5% by weight zinc.

Abstract: When using AA3000 series and AA1000 series aluminum alloys to produce extruded products for heat exchanger applications, by controlling the level of copper and nickel in the alloy to very low levels it is possible to produce excellent corrosion resistance both before and after a brazing cycle. To achieve these results, the copper content should be no more than 0.006% by weight and the nickel no more than 0.005% by weight. A typical alloy of the invention contains about 0.001-0.5% by weight manganese, 0.001-0.7% by weight iron, 0.001-0.02% by weight titanium, 0.001-0.3% by weight silicon, less than 0.006% by weight copper, less than 0.005% by weight nickel and 0.001-0.02% by weight zinc, with the balance consisting of aluminum and incidental impurities. No zinc addition to the alloy is required either by zinc spraying or by alloy addition.

Abstract: When using AA3000 series and AA1000 series aluminum alloys to produce extruded products for heat exchanger applications, by controlling the level of copper and nickel in the alloy to very low levels it is possible to produce excellent corrosion resistance both before and after a brazing cycle. To achieve these results, the copper content should be no more than 0.006% by weight and the nickel no more than 0.005% by weight. A typical alloy of the invention contains about 0.001-0.5% by weight manganese, 0.001-0.7% by weight iron, 0.001-0.02% by weight titanium, 0.001-0.3% by weight silicon, less than 0.006% by weight copper, less than 0.005% by weight nickel and 0.001-0.02% by weight zinc, with the balance consisting of aluminum and incidental impurities. No zinc addition to the alloy is required either by zinc spraying or by alloy addition.