US3620719A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of vacuum refining high-temperature alloys
Assignee: Northrop Grumman Space and Mission Systems Corp
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Filing: 1969-11-12
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Granted: 1971-11-16
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Expires: 1989-11-12
Abstract
Abstract Covers a method of making nickel-base alloys characterized by markedly improved rupture ductility particularly in the intermediate temperature range. This includes the steps of charging to a furnace crucible a base charge of carbon and a mixture of nonreactive metals comprising at least nickel, vacuum refining said charge by heating it to a melt at a temperature ranging from about 2,550* F. to about 2,750* F. at a pressure less than 50 microns and completing said refining by further heating the charge to a melt temperature ranging from about 2,800* F. to about 3,000* F. for a period of time until carbon deoxidation is complete. The melt is cooled, at least one reactive metal added thereto, and the nickel alloy is then teemed.
Inventors
- 👤 Harold L Wheaton
- 👤 Edward G Pekarek
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 11:42
CPC Classifications
C; C22; C22C; C22C1/00; C22C1/02; C22C1/023
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
21 words
The method of claim 1 wherein said melt is cooled to about 2600* -2700* F. prior to addition of reactive metal.
Claim 2
Dependent Claim
23 words
The method of claim 1 wherein the total time of heating prior to addition of reactive metal is at least about 3 hours.
Claim 3
Dependent Claim
30 words
The method of claim 1 wherein both the initial heat step and final heat step are carried out at a time ranging from about one-sixth hour to about 5 hours.
Claim 4
Dependent Claim
31 words
The method of claim 1 wherein said basE charge also contains at least one metal selected from the group consisting of cobalt, chromium, tantalum, molybdenum, tungsten, columbium, vanadium, and mixtures thereof.
Claim 5
Dependent Claim
24 words
The method of claim 1 wherein said melt is heated to about 2800* to about 3000* F. after the addition of the reactive metals.
Claim 6
Dependent Claim
24 words
The method of claim 1 wherein said reactive metal is selected from the group consisting of aluminum, zirconium, boron, titanium, hafnium and mixtures thereof.
Claim 7
Dependent Claim
17 words
The method of claim 1 wherein the carbon added is present in the form of graphite powder.
Claim 8
Dependent Claim
21 words
The method of claim 1 wherein said carbon deoxidation is considered complete when the rate of gas evolution essentially reaches equilibrium.
Claim 9
Dependent Claim
68 words
The method of claim 1 wherein the alloy is comprised of, by weight, 0.05 to 0.15 percent carbon, 7 to 9 percent chormium, 9 to 11 percent cobalt, 4 to 8 percent tantalum, 3 to 7 percent molybdenum, 0.75 to 1.25 percent titanium, 5.5 to 6.5 percent aluminum, 0.01 to 0.02 percent boron, 0.05 to 0.10 percent zirconium, up to 3 percent hafnium with the balance essentially nickel.
Claim 10
Dependent Claim
64 words
The method of claim 1 wherein the alloy is comprised of, by weight, 0.10 to 0.20 percent carbon, 8 to 10 percent chromium, 9 to 11 percent cobalt, 0.5 to 1.5 percent columbium, 11 to 14 percent tungsten, 1.5 to 2.5 titanium, 4.5 to 5.5 aluminum, 0.01 to 0.02 boron, 0.03 to 0.08 zirconium, up to 3 percent hafnium, with the balance essentially nickel.
Claim 11
Dependent Claim
57 words
The method of claim 1 wherein the alloy is comprised of, by weight, 0.04 to 15 percent carbon, 14 to 16 percent chromium, 3 to 5 percent molybdenum, 3 to 4 percent titanium, 4 to 5 percent aluminum, 14 to 16 percent cobalt, 0.005 to 0.03 boron, up to 3 percent hafnium, with the balance essentially nickel.
References Cited (Backward Citations)
US3304176A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-15 | 1975-05-17 | 1975-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-15 | 1979-05-17 | 1979-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-15 | 1983-05-17 | 1983-11-16 | $7700.00 | Window Closed / Lapsed |