US4407775A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pressureless consolidation of metallic powders
Assignee: United States Department of the Interior
•
Filing: 1981-04-27
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Granted: 1983-10-04
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Expires: 2001-04-27
Abstract
Abstract Pressureless consolidation of metallic powders is achieved by sintering, in a nonoxidizing atmosphere, a blend of the metallic powder with a small amount of finely divided lithium tetraborate.
Inventors
- 👤 James L. Holman, Jr.
- 👤 John F. McIlwain
- 👤 L. A. Neumeier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 02:03
CPC Classifications
B; B22; B22F; B22F3/00; B22F3/10; B22F3/1003
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
71 words
A process for pressureless consolidation of alloy powders, said alloys containing a ferrous alloy, consisting essentially of: blending the alloy powder with about 0.25 to 1 percent of lithium tetraborate powder; and placing the resulting admixture in an open mold, and heating in a nonoxidizing atmosphere at an elevated temperature that is below the solidus temperature of the powder for a time sufficient to effect substantial consolidation of the powder particles.
Claim 2
Dependent Claim
71 words
A process for pressureless consolidation of alloy powders, said alloys containing a ferrous alloy, consisting essentially of: blending the alloy powder with about 0.25 to 1 percent of lithium tetraborate powder; and placing the resulting admixture in an open mold, and heating in a nonoxidizing atmosphere at an elevated temperature that is below the solidus temperature of the powder for a time sufficient to effect substantial consolidation of the powder particles.
Claim 3
Dependent Claim
18 words
The process of claim 1 in which the non-oxidizing atmosphere consists of a vacuum or an inert gas.
Claim 4
Dependent Claim
16 words
The process of claim 1 in which the elevated temperature is about 1200° to 1250° C.
Claim 5
Dependent Claim
22 words
The process of claim 1 in which the elevated temperature is within about 100° C. of the solidus temperature of the powder.
Claim 6
Dependent Claim
36 words
The process of claim 1 in which the admixture is heated at a temperature and for a time sufficient to cause a densification of the powder particles of at least about 90 percent of theoretical density.
References Cited (Backward Citations)
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US3166833A
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US3704508A
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US4227927A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-10-03 | 1987-04-04 | 1987-10-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-10-03 | 1991-04-04 | 1991-10-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-10-03 | 1995-04-04 | 1995-10-04 | $7700.00 | Window Closed / Lapsed |