Reynolds Metals Company

The United States of America as Represented by the Administrator of the

Subhasish Sircar

William A Cassada, Iii

Baolute Ren

Joel M Stoltzfus

Rajeev G Kamat

An aluminum alloy article containing the alloying amounts of iron, silicon, manganese, titanium, and zinc has controlled levels of iron and manganese to produce an alloy article that combines excellent corrosion resistant with good formability. The alloy article composition employs a controlled ratio of manganese to iron and controlled total amounts of iron and manganese to form intermetallic compounds in the final alloy article. The electrolytic potential of the intermetallic compounds match the aluminum matrix of the article to minimize corrosion. The levels of iron and manganese are controlled so that the intermetallic compounds are present in a volume fraction that allows the alloy article to be easily formed. The aluminum alloy composition is especially adapted for extrusion processes, and tubing that are used in heat exchanger applications.

Aluminum alloys with optimum combinations of formability, corrosion resistance, and hot workability, and methods of use

A free machining aluminum alloy contains an effective amount of one or more high melting point constituents that provide enhanced machining capability. The high melting point constituents occupy from about 0.1 to about 3.0 volume percent of the aluminum alloy. The constituents can be any material that is essentially insoluble in the aluminum alloy matrix so as to form a discontinuity and one that will resist deformation during machining to enhance the formation of voids between the matrix and the free machining constituents. The constituents include elements, nitrides, oxides, borides, carbides, silicides, aluminides and combinations thereof that have a high melting point and high strength and low solubility in aluminum at the elevated temperature so that the constituents resist deformation during the machining operation. The free machining aluminum alloy can be formed as a workpiece and subjected to any machining operation.

Free machining aluminum alloy with high melting point machining constituent

An aluminum alloy composition includes controlled amounts of iron, manganese, zinc, zirconium, vanadium, and titanium to effectively inhibit grain growth during exposure to elevated temperatures while maintaining extrudability and corrosion resistance. The composition is especially adapted for use as micro-multivoid tubing for brazed heat exchanger applications and has a post-braze grain structure that is more resistant to intergranular corrosion so as to reduce or eliminate heat exchanger failures during service.

Corrosion and grain growth resistant aluminum alloy

Free machining aluminum alloy with high melting point machining constituent and method of use

One free machining aluminum alloy includes bismuth as a free machining elemental constituent that functions as a discontinuity in the aluminum alloy matrix rather than a low melting point compound. Using bismuth in weight percents of the total composition ranging between 0.1% and 3.0% improves both machinability and mechanical properties. The bismuth can act as a substitute for another free machining constituent in a free machining aluminum alloy or can be added to an aluminum alloy to improve its machinability. Another free machining aluminum alloy has bismuth and tin as free machining constituents for improved machining. When using bismuth and tin, the bismuth ranges between 0.1 and 3.0% by weight and the tin ranges between 0.1 and 1.5% by weight.

Free machining aluminum alloy containing bismuth or bismuth-tin for free machining and a method of use

Methods of improving the corrosion resistance and hot working productivity of AA7000 series aluminum alloys include, in one mode, the steps of treating a stock material to form a globular microstructure, preferably by a thermal conversion treatment, and subsequently hot working the treated stock material, quenching it and aging it. The globular microstructure permits increasing the hot working rate to attain T6 properties using only a T5 temper practice and without adverse effect on the surface of the hot worked product as a result of the increased hot working rate. Consequently, an acceptable product is made at a significantly lower cost due to the increased hot working rates and fewer processing steps. The method also improves the corrosion resistance, particularly exfoliation corrosion resistance, of the product such that corrosion resistance generally attainable using only a T7 temper practice is achieved using only a T5 temper practice.

Methods of improving hot working productivity and corrosion resistance in AA7000 series aluminum alloys and products therefrom

A free-machining alloy is disclosed containing bismuth and indium. The free-machining constituents act as low melting point compounds for machining and are specially adapted for use in aluminum alloys such as AA6000 series and AA 2000 series alloys. The bismuth and indium are effective replacements for the lead and bismuth addition used previously to improve machinability while providing a high impact energy free machining alloy.

Free-machining aluminum alloy and method of use

An aluminum alloy article consisting essentially of controlled amounts of iron, silicon, copper, manganese, magnesium, titanium, zinc, zirconium and free machining elements with the balance being aluminum and incidental impurities is adapted for use as a connector block in a heat exchanger assembly. The connector block has a connector block body with at least one machined portion therein and is configured to be brazed to a portion of the heat exchanger, particularly the heat, exchanger header. The aluminum alloy combines the properties of machinability, corrosion resistance, strength and brazeability. A connector block made from the aluminum alloy can be machined to the right configuration and can be brazed to the heat exchanger header to form a high quality brazed joint. In addition, the connector block can withstand the corrosive environment associated with the heat exchanger and has the necessary mechanical properties to interface with other heat exchanger components.

Aluminum alloy article and method of use

An aluminum-based alloy composition having improved combinations of corrosion resistance, drawability, bendability and extrudability consists essentially of, in weight percent, not more than about 0.03% copper, between about 0.1 and up to about 1.5% manganese, between about 0.03 and about 0.35% titanium, an amount of magnesium up to about 1.0%, less than 0.01% nickel, between about 0.06 and about 1.0% zinc, an amount of zirconium up to about 0.3%, amounts of iron and silicon up to about 0.50%, up to 0.20% chromium, with the balance aluminum and inevitable impurities. A process of making an aluminum alloy article having high corrosion resistance, drawability, bendability and hot deformability is also provided.

Corrosion resistant, drawable and bendable aluminum alloy, process of

An aluminum-based alloy composition having improved corrosion resistance and extrudability consists essentially of, in weight percent, an amount of copper up to about 0.03%, between about 0.1 and 0.5% manganese, between about 0.03 and 0.30% titanium, between about 0.06 and 1.0% zinc, an amount of iron up to about 0.50%, between about 0.05 and 0.12% Si, less than 0.01% manganese, less than 0.01% nickel, up to 0.5% chromium with the balance aluminum and incidental impurities. A process of making an aluminum alloy article having high corrosion resistance also is provided.

Corrosion resistant aluminum alloy

A method of improving the corrosion properties of an aluminum alloy product containing solid solution alloying elements includes the step of rapidly quenching the alloy product after it has been heated or hot deformed so as to maintain the alloying elements in solid solution to avoid microsegregation of the solid solution alloying elements and minimize preferential sites for corrosion onset.

Method of improving the corrosion resistance of aluminum alloys and

Apparatus and method are disclosed for producing oxides of metals and of metal alloys. The metal or alloy is placed in an oxygen atmosphere in a combustion chamber and ignited. Products of the combustion include one or more oxides of the metal or alloy in powdered form. In one embodiment of the invention a feeder is provided whereby material to be oxidized by combustion can be advanced into a combustion chamber continuously. A product remover receives the powder product of the combustion.

Method and apparatus for production of powders

A temperature profile is determined of a metal sample for the metal to be converted to establish a temperature range indicative of a partially solid and partially liquid state of the metal. With this temperature profile, a metal preform is heated at a controlled rate from a temperature below the temperature range to a temperature within the range defined by the temperature profile to achieve a select percent by volume of liquid in the metal. This controlled heating to a desired temperature, which may be at a uniform rate, followed by holding at the desired temperature, thermally converts a dendritic structure of the material into a globular structure. The thermally converted metal preform is then recovered for subsequent use such as shaping into a desired article.

Method of forming product having globular microstructure

A free-machining alloy is disclosed containing bismuth, tin and indium. The free-machining constituents act as low melting point compounds for machining and are specially adapted for use in aluminum alloys such as AA6000 series and AA 2000 series alloys. The bismuth, tin and indium are effective replacements for the lead and bismuth addition used previously to improve machinability.

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Richmond, VA, United States of America

Subhasish Sircar