Patent US4295901A successfully refreshed from Google Patents.
US4295901A
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Method of imparting a fine grain structure to aluminum alloys having precipitating constituents
Assignee: Boeing North American Inc
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Filing: 1979-11-05
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Granted: 1981-10-20
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Expires: 1999-11-05
Abstract
Abstract A method is provided to impart a fine grain structure to aluminum alloys which have precipitating constituents. The alloy is overaged to form coarse precipitates, and then plastically deformed at least 40%. Deformation is accomplished at a temperature above the alloy's recrystallization temperature and below its solvus temperature at a sufficiently high rate to introduce strain energy into the alloy before complete recovery can occur. The alloy is subsequently held at a recrystallization temperature to form a new fine grain structure.
Inventors
- 👤 Wayne M. Robertson
- 👤 John A. Wert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:04
CPC Classifications
C; C22; C22F; C22F1/00; C22F1/04
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
170 words
An improvement in a method of imparting a fine grain structure to an aluminum alloy having a precipitating constituent, said method having steps of: providing an aluminum alloy having a precipitating constituent; dissolving at least some of said precipitating constituent in said alloy by heating said alloy to a solid solution temperature; cooling said alloy to a temperature below said solid solution temperature; overaging said alloy at an overaging temperature to form precipitates; plastically straining said alloy; and recrystallizing said alloy by heating it above the minimum recrystallization temperature, whereby said precipitates form nuclei for the recrystallization and controlled growth of a fine grain structure; said improvement being characterized in that said step of plastically straining said alloy comprises: heating said alloy to a temperature in the range above said overaging temperature and below said alloy's solvus temperature and reducing its cross-sectional area a total of 40% minimum at a sufficiently high rate to introduce strain energy into said alloy so that complete recovery of said alloy does not occur.
Claim 2
Dependent Claim
170 words
An improvement in a method of imparting a fine grain structure to an aluminum alloy having a precipitating constituent, said method having steps of: providing an aluminum alloy having a precipitating constituent; dissolving at least some of said precipitating constituent in said alloy by heating said alloy to a solid solution temperature; cooling said alloy to a temperature below said solid solution temperature; overaging said alloy at an overaging temperature to form precipitates; plastically straining said alloy; and recrystallizing said alloy by heating it above the minimum recrystallization temperature, whereby said precipitates form nuclei for the recrystallization and controlled growth of a fine grain structure; said improvement being characterized in that said step of plastically straining said alloy comprises: heating said alloy to a temperature in the range above said overaging temperature and below said alloy's solvus temperature and reducing its cross-sectional area a total of 40% minimum at a sufficiently high rate to introduce strain energy into said alloy so that complete recovery of said alloy does not occur.
Claim 3
Dependent Claim
28 words
The improvement as claimed in claim 1, wherein heating said alloy for said recrystallizing step is accomplished while said alloy is still hot from said plastic straining step.
Claim 4
Dependent Claim
32 words
The improvement as claimed in claim 1, wherein said alloy is cooled to below said minimum recrystallization temperature after said step of plastically straining and before said step of recrystallizing said alloy.
Claim 5
Dependent Claim
28 words
The method as claimed in claim 1 wherein said step of reducing its cross-sectional area comprises passing said alloy between a pair of rolls in a rolling mill.
Claim 6
Dependent Claim
19 words
The method as claimed in claim 1, wherein said step of reducing its cross-sectional area comprises a forging operation.
References Cited (Backward Citations)
US4092181A
Cited
US4092181B1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-10-19 | 1985-04-20 | 1985-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-10-19 | 1989-04-20 | 1989-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-10-19 | 1993-04-20 | 1993-10-20 | $7700.00 | Window Closed / Lapsed |