US3853540A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Desulfurization of vacuum-induction-furnace-melted alloys
Assignee: Latrobe Steel Co
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Filing: 1973-04-11
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Granted: 1974-12-10
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Expires: 1993-04-11
Abstract
Abstract Nickel-base, cobalt-base and iron-base alloys melted in vacuuminduction furnaces are desulfurized to very low sulfur levels by reacting them with slag-forming mixtures comprising high purity lime and a fluxing agent, under reducing conditions, so as to form a slag no hotter than the melt. The alloys so produced display unexpected improvements in physical properties and in hot workability.
Inventors
- 👤 R Schlatter
- 👤 J Stroup
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:37
CPC Classifications
C; C22; C22B; C22B9/00; C22B9/10; C21; C21C; C21C7/00; C21C7/04; C21C7/064
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
104 words
THE METHOD OF DESULFURIZING AN ALLOY OF THE GROUP CONSISTING OF NICKEL-BASE, COBALT-BASE AND IRON-BASE ALLOYS IN A BASICLINED VACUUM VESSEL UNDER REDUCED PRESSURE COMPRISING BRINGING THE MOLTEN ALLOY INTO CONTACT UNDER REDUCING CONDITIONS WITH A BASIC SLAGE HAVING A TEMPERATURE NO HIGHER THAN THAT OF THE ALLOY, THE SLAG BEING FORMED BY ADDING TO THE ALLOY A SLAGFORMING MIXTURE COMPRISING LIME HAVING A CALCIUM OXIDE CONTENT GREATER THAN ABOUT 98 PERCENT AND A NEUTRAL FLUXING AGENT CAPABLE OF RENDERING SLAG FLUID AND REACTIVE AT RELATIVELY LOW SLAG TEMPERATURES, IN AMOUNT BETWEEN ABOUT 5 PERCENT AND ABOUT 25 PERCENT OF THE MIXTURE BY WEIGHT.
Claim 2
Independent Claim
104 words
THE METHOD OF DESULFURIZING AN ALLOY OF THE GROUP CONSISTING OF NICKEL-BASE, COBALT-BASE AND IRON-BASE ALLOYS IN A BASICLINED VACUUM VESSEL UNDER REDUCED PRESSURE COMPRISING BRINGING THE MOLTEN ALLOY INTO CONTACT UNDER REDUCING CONDITIONS WITH A BASIC SLAGE HAVING A TEMPERATURE NO HIGHER THAN THAT OF THE ALLOY, THE SLAG BEING FORMED BY ADDING TO THE ALLOY A SLAGFORMING MIXTURE COMPRISING LIME HAVING A CALCIUM OXIDE CONTENT GREATER THAN ABOUT 98 PERCENT AND A NEUTRAL FLUXING AGENT CAPABLE OF RENDERING SLAG FLUID AND REACTIVE AT RELATIVELY LOW SLAG TEMPERATURES, IN AMOUNT BETWEEN ABOUT 5 PERCENT AND ABOUT 25 PERCENT OF THE MIXTURE BY WEIGHT.
Claim 3
Dependent Claim
33 words
The method of claim 1 in which the lime contains not more than about 0.5 percent silica, not more than 0.3 percent iron oxide and not more than about 0.3 percent manganese oxide.
Claim 4
Dependent Claim
17 words
The method of claim 2 in which the lime contains not more than 0.05 percent lead oxide.
Claim 5
Dependent Claim
35 words
The method of claim 1 in which the neutral fluxing agent is one or more members selected from the group consisting of calcium fluoride, barium fluoride, magnesium fluoride, sodium-aluminum fluoride and the rare earth fluorides.
Claim 6
Dependent Claim
31 words
The method of claim 4 in which the neutral fluxing agent also includes one or more members selected from the group consisting of alumina, barium oxide, nickel oxide and molybdenum oxide.
Claim 7
Dependent Claim
36 words
The method of claim 1 in which the reducing conditions are obtained by including in the slag-forming mixture a reducing agent in amounts between about 1 percent and about 15 percent of the mixture by weight.
Claim 8
Dependent Claim
39 words
The method of claim 6 in which the reducing agent is one or more of the constituents carbon, calcium carbide, silicon, silicon carbide, calcium, calcium silicide, aluminum, magnesium, the rare earth metals, the rare earth silicides, and alloys thereof.
Claim 9
Dependent Claim
28 words
The method of claim 1 in which the weight of the slag-forming mixture is between about 0.1 percent and about 2 percent of the weight of the melt.
Claim 10
Dependent Claim
12 words
The method of claim 1 in which the vessel is a vacuum-induction-furnace.
Claim 11
Dependent Claim
18 words
The method of claim 9 in which the basic lining of the vacuum-induction-furnace is a magnesia spinel refractory.
References Cited (Backward Citations)
US3099552A
Cited
US3198624A
Cited
US3194649A
Cited
US3218156A
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US3396100A
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US3547622A
Cited
US3695946A
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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) | 1977-12-09 | 1978-06-10 | 1978-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-09 | 1982-06-10 | 1982-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-09 | 1986-06-10 | 1986-12-10 | $7700.00 | Window Closed / Lapsed |