Alcoa Inc.

Arconic Technologies LLC

Arconic Corporation

Baolute Ren

Raymond J Kilmer

Stephen F Baumann

Harry R Zonker

Michael P Danz

Andreas K Kulovits

Marvin Goins

John F Butler, Jr

Tao Zhou

Andreas Kulovits

An apparatus, material and method for forming a brazing sheet has a high strength core bonded with corrosion protection layer on the coolant side and/or layers on both airside and coolant side. The material enables heat exchanger components, such as tube, header, plate, etc., for applications, such as automotive heat exchangers, that require high fatigue life as well as high service life in a corrosive environment.

Corrosion resistant high strength brazing sheet

New aluminum alloy brazing sheets are disclosed. The new aluminum alloy brazing sheets may include a core, an interliner layer adjacent the core, and a braze liner adjacent the interliner layer. The interliner layer may include a first aluminum alloy having at least 0.35 wt. % Si and from 0.05 to 2.0 wt. % Mg. The braze liner may include a second aluminum alloy having 0.05 to 2.0 wt. % Mg. The first aluminum alloy and the second aluminum alloy may include an amount of magnesium sufficient to achieve T(IL)&#x2265;5&#xb0; C. T(BL). The new aluminum alloy brazing products may be useful, for instance, in fluxfree brazing.

Aluminum alloy brazing sheets for fluxless brazing

An apparatus, material and method for forming a brazing sheet has a composite braze liner layer of low melting point aluminum alloy and 4000 series braze liner. The low melting point layer of the composite braze liner facilitates low temperature brazing and decrease of the diffusion of magnesium from the core into the composite braze liner. The reduction of magnesium diffusion also lowers the formation of associated magnesium oxides at the braze joint interface that are resistant to removal by Nocolok flux, thereby facilitating the formation of good brazing joints through the use of low temperature controlled atmosphere brazing (CAB) and Nocolok flux. The apparatus also enables the production of brazing sheet materials with high strength and good corrosion property.

Composite braze liner for low temperature brazing and high strength materials

In one embodiment, a brazing sheet comprises: a core layer, a braze liner on the first side of the core layer; and a waterside liner on the second side of the core layer. The core layer is comprised of a 3xxx series aluminum alloy. The waterside liner is an aluminum alloy comprising: 7-20 wt % Zn; up to 0.25 wt % Si; up to 0.1 wt % Cu; up to 0.25 wt % Mn; up to 0.1 wt % Mg; and up to 0.1 wt % Cr. In some embodiments, the brazing sheet has a thickness of 60-180 microns. In some embodiments, the waterside liner comprises 1-15% of the thickness of the brazing sheet.

Brazing sheet

A five layer sheet for vacuum brazing has a core layer of 3XXX aluminum alloy and two interliner layers of 5XXX aluminum alloy bonded to the core layer. Two layers of 4XXX aluminum alloy are bonded to the two interliner layers. An elevated quantity of Mg in the interliner layers can provide enhanced strength, facilitate brazing and provide corrosion protection. A low zinc composition for the sheet also facilitates vacuum brazing.

Multilayer brazing sheet for vacuum braze applications

An aluminum sheet product comprises: a core layer comprising one of a 3xxx, 5xxx and 6xxx aluminum alloy; and a liner layer comprising one of a 3xxx aluminum alloy having an additive of 0.5-5% Zn, and a 7xxx aluminum alloy. In some embodiments, the aluminum sheet product r has an O temper pre-braze tensile strength of at least 20 Ksi. In some embodiments the corrosion potential difference between the liner and core is at least 30 millivolts. In some embodiments, the aluminum sheet product further comprises an inner layer comprising one of a 3xxx and a 4xxx aluminum alloy.

Multi-layer aluminum alloy sheet product for tubes for heat exchangers

Various illustrative embodiments of a multi-layer brazing sheet are provided. The multi-layer brazing sheet demonstrates improved corrosion resistance on its exposed air side surface.

Multi-layer brazing sheet

A heat exchanger tube having enhanced corrosion resistance and improved resistance to high burst pressures. The heat exchanger tube comprises an aluminum alloy that consists essentially of about 0.01-1.5% silicon, up to about 1.2% copper, up to about 2.0% manganese, about 0.01-1.0% iron, about 0.01-5.0% zinc, up to about 0.02% titanium and the balance substantially aluminum and incidental elements and impurities.

Heat exchanger tubing by continuous extrusion

A heat exchanger tubing includes at least a pair of tubes () that are connected to and separated by a connecting member (). The connecting member () has a number of fin projections () extending at an angle from the member (), each fin projection () having an opening () to allow air to pass through the member. The tubing is arranged between headers () of a heat exchanger () in an angled configuration so that the fins align with the air flow (A) passing across the tubing for enhanced heat exchange. The connecting member () can also be multivoid tubing (), which has the fin projections for heat transfer or uses the passageways () in the multivoid tubing and fluid flowing through the channels for heat exchange.

Heat exchanger tubing with connecting member and fins and methods of heat exchange

A heat exchanger tubing has one or more channels formed therein for fluid flow, with channel walls between the channels having openings extending between two opposing surfaces of the tubing. The channel walls are angled with respect to the opposing surfaces to increase the surface area of the openings. The tubing is tilted with respect to the headers in a heat exchanger assembly so that the openings in the tubing align with the direction of airflow passing over the heat exchanger. A heat exchanger assembly employing the tubing is effective without conventional fin stock, thus reducing the cost and manufacturing time when making the heat exchanger assemblies but without sacrificing heat exchange capability.

Heat exchanger tubing and heat exchanger assembly using said tubing

A corrosion resistant aluminum alloy has controlled amounts of iron, manganese, chromium, and titanium along with levels of copper, silicon, nickel, and no more than impurity levels of zinc. The alloy chemistry is tailored such that the electrolytic potential of the grain boundaries matches the alloy matrix material to reduce intergranular corrosion. The alloy is particularly suited for the manufacture of tubing for heat exchangers using extrusion and brazing techniques.

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Lititz, PA, United States of America

Baolute Ren