US5041343A — Process for improving the corrosion resistance of…

Claim 1

Independent Claim 125 words

A process for producing a corrosion resistant aluminum composite sheet product for use in brazing, which comprises: (a) casting an aluminum-base ore material containing no more than 0.4% iron, no more than 0.15% silicon, from about 0.1% to about 0.6% copper and from about 0.7% to about 1.5% manganese, (b) cladding the as-cast core material with an aluminum-base brazing alloy containing silicon as the primary alloying element, with hot rolling to form a sheet product, and (c) directly cold rolling said sheet product to final gauge, said cold rolled product being formed without substantial homogenization or interannealing and being capable of forming a corrosion resistant band of dense precipitate in the core alloy immediately adjacent the cladding upon being subjected to a brazing heat cycle.

Claim 2

Dependent Claim 125 words

A process for producing a corrosion resistant aluminum composite sheet product for use in brazing, which comprises: (a) casting an aluminum-base ore material containing no more than 0.4% iron, no more than 0.15% silicon, from about 0.1% to about 0.6% copper and from about 0.7% to about 1.5% manganese, (b) cladding the as-cast core material with an aluminum-base brazing alloy containing silicon as the primary alloying element, with hot rolling to form a sheet product, and (c) directly cold rolling said sheet product to final gauge, said cold rolled product being formed without substantial homogenization or interannealing and being capable of forming a corrosion resistant band of dense precipitate in the core alloy immediately adjacent the cladding upon being subjected to a brazing heat cycle.

Claim 3

Dependent Claim 15 words

A process according to claim 1, wherein the core alloy contains up to 0.8% magnesium.

Claim 4

Dependent Claim 17 words

A process according to claim 1, wherein the core alloy contains about 0.05% to about 0.25% zirconium.

Claim 5

Dependent Claim 43 words

A process according to claim 1, wherein the core alloy comprises no more than 0.2% iron, no more than 0.1% silicon, from about 0.2% to about 0.4% copper, from about 0.2% to about 0.4% magnesium and from about 0.9% to about 1.1% manganese.

Claim 6

Dependent Claim 18 words

A process according to claim 4, wherein the core alloy also contains about 0.1% to about 0.15% zirconium.

Claim 7

Dependent Claim 24 words

A process according to claim 1, wherein the core material is heated to a temperature between 425° and 525° C. prior to hot rolling.

Claim 8

Dependent Claim 24 words

A process according to claim 1, wherein the core material is heated to a temperature between 475° and 500° C. prior to hot rolling.

Claim 9

Dependent Claim 16 words

A process according to claim 1, wherein the product rolled to final gauge is then annealed.

Claim 10

Dependent Claim 27 words

A process according to claim 8, wherein the product rolled to final gauge is either partially annealed at about 250°-350°C. or is fully annealed at about 350°-425°C.

Claim 11

Dependent Claim 33 words

A process according to claim 1, wherein the product obtained is subjected to a brazing heat cycle whereby a band of dense precipitate is formed in the core alloy immediately adjacent the cladding.

Claim 12

Dependent Claim 104 words

An aluminum alloy composite sheet material suitable for forming into parts to be assembled and brazed comprising (a) a cast aluminum-base core containing no more than 0.4% iron, no more than 0.15% silicon, from about 0.1% to about 0.6% copper and from about 0.7% to about 1.5% manganese and (b) an aluminum-base brazing alloy containing silicon as the primary alloying element clad on at least one side of said core, wherein the manganese in the core is substantially in solid solution and/or in the form of a fine, uniformly distributed precipitate of manganese-containing particles having sizes in the range of 0.03 to 0.1 μm.

Claim 13

Dependent Claim 104 words

An aluminum alloy composite sheet material suitable for forming into parts to be assembled and brazed comprising (a) a cast aluminum-base core containing no more than 0.4% iron, no more than 0.15% silicon, from about 0.1% to about 0.6% copper and from about 0.7% to about 1.5% manganese and (b) an aluminum-base brazing alloy containing silicon as the primary alloying element clad on at least one side of said core, wherein the manganese in the core is substantially in solid solution and/or in the form of a fine, uniformly distributed precipitate of manganese-containing particles having sizes in the range of 0.03 to 0.1 μm.

Claim 14

Dependent Claim 28 words

An aluminum alloy composite sheet according to claim 11, wherein the core contains at least 0.6% manganese in solid solution and/or in the form of said fine precipitate.

Claim 15

Dependent Claim 109 words

A brazed aluminum composite produced from a brazable composite comprising (a) a cast aluminum-base core containing no more than 0.4% iron, no more than 0.15% silicon, from about 0.1% to about 0.6% copper and from about 0.7% to about 1.5% manganese and (b) an aluminum-base brazing alloy containing silicon as the primary alloying element clad on at least one side of said core. wherein a silicon-rich band of dense precipitate formed in the core alloy immediately adjacent the brazing alloy cladding, said band having a thickness of about 20-15 μm and characterized by substantially less manganese in solid solution in the band than in the core outside the band.

Claim 16

Dependent Claim 109 words

A brazed aluminum composite produced from a brazable composite comprising (a) a cast aluminum-base core containing no more than 0.4% iron, no more than 0.15% silicon, from about 0.1% to about 0.6% copper and from about 0.7% to about 1.5% manganese and (b) an aluminum-base brazing alloy containing silicon as the primary alloying element clad on at least one side of said core. wherein a silicon-rich band of dense precipitate formed in the core alloy immediately adjacent the brazing alloy cladding, said band having a thickness of about 20-15 μm and characterized by substantially less manganese in solid solution in the band than in the core outside the band.

Claim 17

Dependent Claim 22 words

A brazed aluminum composite according to claim 13, wherein the core outside the band contains at least 0.3% manganese in solid solution.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1994-08-19	1995-02-18	1995-08-20	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1998-08-19	1999-02-18	1999-08-20	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2002-08-19	2003-02-18	2003-08-20	$7700.00	Window Closed / Lapsed

Process for improving the corrosion resistance of brazing sheet

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