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AssigneeAlcan International Limited
InventorsPierre Henri Marois, Nicholas Parson
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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.
A furnace brazed aluminum alloy extruded product wherein the alloy consists essentially of an aluminum alloy of the AA3000 series containing less than 0.006% by weight copper and less than 0.005% by weight nickel.
A population of aluminum alloy ingots for use in producing extruded heat exchange tubes, said population of ingots consisting essentially of an aluminum alloy of the AA3000 series containing less than 0.006% by weight copper and less than 0.005% by weight nickel.
A process for producing aluminum alloy extruded product having high corrosion resistance which comprises selecting a population of ingots of an aluminum alloy of an AA1000 or AA3000 series whereby the aggregate population contains less than 0.006% by weight copper and less than 0.005% by weight nickel, melting said aggregate population of ingots and extruding the melt into tubing and thereafter subjecting the tubing to a furnace brazing cycle.
Dependencies are inferred from the claim text.