Method of forming aluminium heat exchangers header tanks

Abstract

The invention relates to a method for producing a heat exchanger header tank comprising the steps of providing a tube having a core made from a AA3XXX-aluminium alloy; optionally pre-heating the tube; inserting the tube into a forming tool having a forming cavity with the shape of the final header tank; plugging the ends of the tube; internally pressurising the tube by the use of a gas so as to make it conform to the shape of the tool cavity, thus obtaining the final header tank; removing the header tank from the tool; and cooling the header tank. This method allows an efficient production of header tanks of irregular shapes made of AA3XXX aluminium alloy. The invention also relates to a method for producing a heat exchanger, where the header tank is connected to a plurality of tubes and corrugated fins inserted between the tubes, followed by brazing of the fins to the tubes.

Description

TECHNICAL FIELD[0001]This invention relates to header tanks and methods of producing header tanks, also called manifold tanks, for brazed automotive or stationary aluminium heat exchangers, with almost arbitrary tank shapes. The invention also relates to a heat exchanger comprising the headers formed and manufacturing methods therefore.BACKGROUND OF THE INVENTION[0002]Today's automotive engineers face increasingly large difficulties to fit and assemble all underhood components in a rational fashion. Engines become more powerful and an increasing amount of different components are fitted to support the engine, and to supply passengers with a continuously increasing level of driving experience, safety and comfort. This makes available underhood space a scant resource. Heat exchangers have, almost by default, a rectangular shape which restricts the automotive engineer concerning suitable locations for heat exchanger assembly into the car. Much of the restrictions on heat exchanger geom...

AI Technical Summary

Benefits of technology

"The present invention provides a method for efficiently producing header tanks for heat exchangers from AA3XXX aluminium alloys. The method allows for the formation of non-homogenised tanks that have improved corrosion and mechanical properties compared to deep-drawn tanks made from the same alloys. The method also allows for the production of tanks with complex shapes and contoured fins, which can be brazed to tubes. The use of a hot metal gas forming process eliminates the need for homogenisation and annealing, resulting in cost savings and improved environmental load. The method also allows for the use of non-homogenised alloys, which have higher strength and improved corrosion resistance compared to deep-drawn tanks. The method can be used with either pre-heated or non-heated tubes, and the resulting tanks have low weight and can be optimised at a low cost compared to competing technology."

Problems solved by technology

The group of alloys commonly used for heat exchanger header tanks, AA3XXX, is difficult to form to desired shapes by means of the methods hitherto typically used for manufacturing header tanks.

Previous methods have not been able to satisfy the long felt need for header tanks, which can be brazed and which can be formed in complicated shapes.

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