US4014685A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Manufacture of steel
Assignee: Foseco International Ltd
•
Filing: 1974-11-14
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Granted: 1977-03-29
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Expires: 1994-11-14
Abstract
Abstract The invention is concerned with the desulphurizing of molten steel by the use of a lime-based flux. In addition to lime the flux includes sodium carbonate, an alkali metal or alkaline earth metal fluoride, typically fluorspar, alumina and a metallic reducing agent. In particular, the reducing agent is aluminium or an alloy thereof and is present in an amount of 2 to 15% by weight. To desulphurize molten metal the flux is added to the molten metal in a vessel, typically by injecting the flux in particulate form into the molten metal.
Inventors
- 👤 Evan Thomas Richard Jones
- 👤 Robert Anthony Fishburn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:43
CPC Classifications
C; C21; C21C; C21C7/00; C21C7/04; C21C7/064
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
63 words
A flux composition for use in desulphurising molten steel in a furnace, which composition comprises 50 to 80% by weight of lime, from 1-20% by weight of sodium carbonate, from 5-30% by weight of a fluoride selected from alkali metal and alkaline earth metal fluorides and mixtures thereof, 5-30% by weight of alumina and from 2-15% by weight of a metallic reducing agent.
Claim 2
Dependent Claim
63 words
A flux composition for use in desulphurising molten steel in a furnace, which composition comprises 50 to 80% by weight of lime, from 1-20% by weight of sodium carbonate, from 5-30% by weight of a fluoride selected from alkali metal and alkaline earth metal fluorides and mixtures thereof, 5-30% by weight of alumina and from 2-15% by weight of a metallic reducing agent.
Claim 3
Dependent Claim
13 words
A flux composition as claimed in claim 1, wherein the fluoride is fluorspar.
Claim 4
Dependent Claim
44 words
A flux composition as claimed in claim 2 which contains from 50 to 80% by weight of lime, from 1 to 15% by weight of sodium carbonate, from 5 to 25% by weight of fluorspar and from 5 to 25% by weight of alumina.
Claim 5
Dependent Claim
18 words
A flux composition as claimed in claim 1, which contains from 60 to 80% by weight of lime.
Claim 6
Dependent Claim
21 words
A flux composition as claimed in claim 1, wherein the metallic reducing agent is selected from aluminium and aluminium containing alloys.
Claim 7
Dependent Claim
18 words
A flux composition as claimed in claim 2 wherein fluorspar is wholly or partly replaced by sodium fluoride.
Claim 8
Dependent Claim
28 words
A method of desulphurising molten steel in an arc furnace under reducing conditions, which method comprises adding to molten steel a flux composition as claimed in claim 1.
Claim 9
Dependent Claim
23 words
A method as claimed in claim 7 wherein a stream of the flux composition in particulate form is injected into the molten steel.
Claim 10
Dependent Claim
31 words
A method as claimed in claim 7 wherein the composition in particulate form is injected into the molten steel in a medium selected from compressed air, nitrogen, argon and mixtures thereof.
Claim 11
Dependent Claim
27 words
A method as claimed in claim 7 wherein the flux composition in particulate form is injected into the molten metal in a medium containing a reducing gas.
Claim 12
Dependent Claim
32 words
A method as claimed in claim 7 wherein the composition in particulate form is injected into the molten metal in a medium containing a reducing gas selected from propane, and natural gas.
Claim 13
Dependent Claim
12 words
Desulphurised steel when manufactured by a method as claimed in claim 7.
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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) | 1980-03-28 | 1980-09-27 | 1981-03-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-03-28 | 1984-09-27 | 1985-03-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-03-28 | 1988-09-27 | 1989-03-29 | $7700.00 | Window Closed / Lapsed |