Patent US3798025A successfully refreshed from Google Patents.
US3798025A
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Vacuum decarburization in rh and dh type degassing systems
Assignee: Allegheny Ludlum Corp
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Filing: 1971-12-29
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Granted: 1974-03-19
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Expires: 1991-12-29
Abstract
Abstract A method for cyclically decarburizing a bath of molten metal such as steel by transferring the molten metal from a first vessel to a second vessel, evacuating the space above the molten metal in the second vessel while subjecting the metal bath in the second vessel to oxygen to decarburize the same, and returning the decarburized metal from the second to the first vessel. The foregoing cycle is repeated while the pressure within the second vessel is progressively reduced and the oxygen introduced into the second vessel varied to decarburize the molten metal bath in steps without substantial oxidation of metal constituents therein.
Inventors
- 👤 S Ramachandran
- 👤 J Fulton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 12:45
CPC Classifications
C; C21; C21C; C21C7/00; C21C7/10
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
50 words
The method of claim 1 wherein a batch of molten metal is transferred to the second vessel, subjected to oxygen, and then returned to the first vessel to complete a cycle, and wherein the pressure is reduced in said second vessel in steps and at the completion of each cycle.
Claim 2
Dependent Claim
33 words
The method of claim 2 wherein said second vessel is above the first vessel and connected thereto through a single snorkel which extends into a molten metal bath contained in said first vessel.
Claim 3
Dependent Claim
35 words
The method of claim 3 including the step of pressurizing the surface of the metal bath in said first vessel to force metal from the first vessel upwardly through said snorkel into the second vessel.
Claim 4
Dependent Claim
30 words
The method of claim 4 wherein the pressure on the surface of the metal bath in the first vessel is reduced as the pressure in the second vessel is reduced.
Claim 5
Dependent Claim
69 words
The method of claim 1 wherein the molten metal continuously flows from said second vessel to said first vessel and is continually returned to said first vessel, and wherein said pressure is continually reduced in said second vessel as the metal moves from the first vessel to the second vessel and then back to the first vessel, until a desired carbon level is reached in said molten metal bath.
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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) | 1977-03-18 | 1977-09-17 | 1978-03-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-18 | 1981-09-17 | 1982-03-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-18 | 1985-09-17 | 1986-03-19 | $7700.00 | Window Closed / Lapsed |