Patent US4968486A successfully refreshed from Google Patents.
Patent US4586964A successfully refreshed from Google Patents.
US4586964A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Corrosion resistant vacuum brazing sheet
Assignee: Kaiser Aluminum and Chemical Corp
•
Filing: 1984-07-26
•
Granted: 1986-05-06
•
Expires: 2004-07-26
Abstract
Abstract A novel process for producing aluminum composite sheet products for roll forming and vacuum brazing is disclosed, which provides an unexpected improvement in the corrosion resistance of the brazed product. According to the process, a composite sheet is annealed to a strain-free state after having been rolled to a thickness which is a critical amount greater than the thickness ultimately sought. Following the annealing step, the sheet is cold worked to the desired thickness, the degree of reduction in this final step being within a critical range which provides the improvement in corrosion resistance to the final product after vacuum brazing.
Inventors
- 👤 Walter D. Finnegan
- 👤 Ralph A. A. Woods
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:04
CPC Classifications
B; B23; B23K; B23K35/00; B23K35/22; B23K35/24; B23K35/28; B23K35/286; Y; Y10; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12736; Y10T428/12764
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
75 words
A method of producing a corrosion resistant wrought aluminum composite sheet product for use in vacuum brazing, which comprises: (a) cladding an aluminum-base core material containing at most a trace amount of chromium with an aluminum-base brazing alloy; (b) rolling said clad material to form a sheet product; (c) annealing said sheet product to a substantially strain-free state; and (d) cold working said sheet product to a reduction of from about 3% to about 20%.
Claim 2
Independent Claim
75 words
A method of producing a corrosion resistant wrought aluminum composite sheet product for use in vacuum brazing, which comprises: (a) cladding an aluminum-base core material containing at most a trace amount of chromium with an aluminum-base brazing alloy; (b) rolling said clad material to form a sheet product; (c) annealing said sheet product to a substantially strain-free state; and (d) cold working said sheet product to a reduction of from about 3% to about 20%.
Claim 3
Dependent Claim
19 words
A method according to claim 1 in which said aluminum-base brazing alloy contains silicon as a primary alloying element.
Claim 4
Dependent Claim
24 words
A method according to claim 1 in which said aluminum-base core material is an alloy containing manganese, magnesium or both as primary alloying elements.
Claim 5
Dependent Claim
21 words
A method according to claim 1 in which said aluminum-base core material is an alloy of the Aluminum Association 3XXX series.
Claim 6
Dependent Claim
21 words
A method according to claim 1 in which said aluminum-base brazing alloy is an alloy of the Aluminum Association 4XXX series.
Claim 7
Dependent Claim
39 words
A method according to claim 1 in which said aluminum-base brazing alloy contains an alkali or alkaline earth metal gettering agent in an amount sufficient to substantially prevent the formation of oxides on the composite surface during vacuum brazing.
Claim 8
Dependent Claim
13 words
A method according to claim 6 in which said gettering agent is magnesium.
Claim 9
Dependent Claim
23 words
A method according to claim 1 in which said brazing alloy occupies from about 0.1% to about 20% of the total composite thickness.
Claim 10
Dependent Claim
23 words
A method according to claim 1 in which said brazing alloy occupies from about 1% to about 15% of the total composite thickness.
Claim 11
Independent Claim
116 words
A method of producing a brazed aluminum composite sheet product having improved resistance to intergranular corrosion, which comprises: (a) cladding an aluminum-base core material containing at most a trace amount of chromium with an aluminum-base brazing alloy containing silicon as a primary alloying element to form a composite having a cladding occupying from about 1% to about 15% of the total composite thickness; (b) rolling said composite to form a sheet product; (c) annealing said sheet product to a substantially strain-free state; (d) cold working said sheet product to a reduction of from about 3% to about 20%; and (e) joining said sheet product at its clad surface to a second aluminum-base material by vacuum brazing.
Claim 12
Independent Claim
116 words
A method of producing a brazed aluminum composite sheet product having improved resistance to intergranular corrosion, which comprises: (a) cladding an aluminum-base core material containing at most a trace amount of chromium with an aluminum-base brazing alloy containing silicon as a primary alloying element to form a composite having a cladding occupying from about 1% to about 15% of the total composite thickness; (b) rolling said composite to form a sheet product; (c) annealing said sheet product to a substantially strain-free state; (d) cold working said sheet product to a reduction of from about 3% to about 20%; and (e) joining said sheet product at its clad surface to a second aluminum-base material by vacuum brazing.
Claim 13
Dependent Claim
46 words
A method according to claim 10 in which said aluminum-base core material is a non-heat-treatable alloy of the Aluminum Association 3XXX series; and said aluminum-base cladding alloy is an alloy of the Aluminum Association 4XXX series and further contains from about 0.1% to about 3.0% magnesium.
Claim 14
Dependent Claim
30 words
A method according to claim 10 in which said aluminum-base core material contains at least one member selected from the group consisting of manganese an magnesium as primary alloying elements.
Claim 15
Dependent Claim
35 words
A method according to claim 10 in which step (e) is conducted at a temperature of from about 1000° F. to about 1200° F. and at a pressure of less than about 10 -2 torr.
Claim 16
Dependent Claim
39 words
A method according to claim 10 in which step (e) is conducted at a temperature of from about 1060° F. to about 1125° F. and at a pressure of from about 10 -4 torr to about 10 -6 torr.
Claim 17
Independent Claim
141 words
A method of producing an aluminum tube-and-fin heat exchanger having improved resistance to corrosion, which comprises: (a) cladding an aluminum-base core material on one side with an aluminum-base brazing alloy containing silicon as a primary alloying element to form a composite having a cladding on one side occupying from about 1% to about 15% of the total composite thickness, said aluminum-base core material containing at most a trace amount of chromium; (b) rolling said composite to form a sheet product; (c) annealing said sheet product to a substantially strain-free state; (d) cold working said sheet product to a reduction of from about 3% to about 20%; (e) roll forming said sheet product into a tube with flattened sides and with the cladding on the exterior; and (f) joining said tube to aluminum-base fin stock at said flattened sides by vacuum brazing.
Claim 18
Independent Claim
141 words
A method of producing an aluminum tube-and-fin heat exchanger having improved resistance to corrosion, which comprises: (a) cladding an aluminum-base core material on one side with an aluminum-base brazing alloy containing silicon as a primary alloying element to form a composite having a cladding on one side occupying from about 1% to about 15% of the total composite thickness, said aluminum-base core material containing at most a trace amount of chromium; (b) rolling said composite to form a sheet product; (c) annealing said sheet product to a substantially strain-free state; (d) cold working said sheet product to a reduction of from about 3% to about 20%; (e) roll forming said sheet product into a tube with flattened sides and with the cladding on the exterior; and (f) joining said tube to aluminum-base fin stock at said flattened sides by vacuum brazing.
Claim 19
Dependent Claim
67 words
A method according to claim 15 in which said aluminum-base core material contains at least one member selected from the group consisting of manganese and magnesium as primary alloying elements and said aluminum-base brazing alloy further contains an alkali or alkaline earth metal gettering agent in an amount sufficient to substantially prevent the formation of oxides on the composite surface during the brazing procedure of step (f).
Claim 20
Dependent Claim
35 words
A method according to claim 15 in which step (e) is conducted at a temperature of from about 1000° F. to about 1200° F. and at a pressure of less than about 10 -2 torr.
Claim 21
Dependent Claim
39 words
A method according to claim 15 in which step (e) is conducted at a temperature of from about 1060° F. to about 1125° F. and at a pressure of from about 10 -4 torr to about 10 -6 torr.
Claim 22
Dependent Claim
63 words
A wrought aluminum vacuum brazing sheet product having improved resistance to intergranular corrosion, formed by: (a) annealing a composite sheet product comprising an aluminum-base core material containing at most a trace amount of chromium clad with an aluminum-base brazing alloy to a substantially strain-free state; and (b) cold working said annealed sheet product to a reduction of from about 3% to about 20%.
Claim 23
Dependent Claim
63 words
A wrought aluminum vacuum brazing sheet product having improved resistance to intergranular corrosion, formed by: (a) annealing a composite sheet product comprising an aluminum-base core material containing at most a trace amount of chromium clad with an aluminum-base brazing alloy to a substantially strain-free state; and (b) cold working said annealed sheet product to a reduction of from about 3% to about 20%.
References Cited (Backward Citations)
US2821014A
Cited
US3498849A
Cited
US3418090A
Cited
US3788824A
Cited
US3881879A
Cited
SU423599A1
Cited
US3994695A
Cited
US3963454A
Cited
US4039298A
Cited
US4172548A
Cited
US4093782A
Cited
US4167410A
Cited
US4172923A
Cited
US4169553A
Cited
US4211827A
Cited
US4339510A
Cited
US4357397A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-05-05 | 1989-11-04 | 1990-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-05-05 | 1993-11-04 | 1994-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-05-05 | 1997-11-04 | 1998-05-06 | $7700.00 | Window Closed / Lapsed |