US3844768A
Expired / Lapsed
US
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Process for refining alloy steels containing chromium and including stainless steels
Assignee: Creusot Loire SA
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Filing: 1972-04-25
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Granted: 1974-10-29
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Expires: 1992-04-25
Abstract
Abstract An alloy steel containing chromium is refined by blowing fluids into the molten steel through double or triple feed tuyeres. Each tuyere first provides a flow of an oxidizing fluid, a second flow of a fluid for diluting the carbon monoxide in the bath and a third peripheral flow of a carbon make-up liquid.
Inventors
- 👤 J Morlet
- 👤 J Saleil
- 👤 P Leroy
- 👤 M Cadart
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 02:25
CPC Classifications
C; C21; C21C; C21C5/00; C21C5/005; C21C7/00; C21C7/04; C21C7/068; C21C7/0685
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
86 words
A PROCESS FOR REFINING AN ALLOY STEEL CONTAINING CHROMIUM WHICH COMPRISES BLOWING FLUIDS INTO THE MOLTEN STEEL THROUGH AT LEAST ONE FEED TUYERE, EACH TUYERE PROVIDING A FIRST FLOW OF AN OXIDISING FLUID, A SECOND FLOW OF A FLUID FOR DILUTING THE CARBON MONOXIDE IN THE BATH, AND A THIRD PERIPHERAL FLOW, WHICH IS PHYSICALLY DISTINCT AND SEPARATE FROM THE SAID FIRST AND SECOND FLOWS IN THE TUYERE, OF A HYDRO-CARBON CONTAINING LIQUID, SAID THIRD FLOW REMAINING IN THE LIQUID STATE UNTIL AFTER LEAVING THE TUYERE.
Claim 2
Dependent Claim
86 words
A PROCESS FOR REFINING AN ALLOY STEEL CONTAINING CHROMIUM WHICH COMPRISES BLOWING FLUIDS INTO THE MOLTEN STEEL THROUGH AT LEAST ONE FEED TUYERE, EACH TUYERE PROVIDING A FIRST FLOW OF AN OXIDISING FLUID, A SECOND FLOW OF A FLUID FOR DILUTING THE CARBON MONOXIDE IN THE BATH, AND A THIRD PERIPHERAL FLOW, WHICH IS PHYSICALLY DISTINCT AND SEPARATE FROM THE SAID FIRST AND SECOND FLOWS IN THE TUYERE, OF A HYDRO-CARBON CONTAINING LIQUID, SAID THIRD FLOW REMAINING IN THE LIQUID STATE UNTIL AFTER LEAVING THE TUYERE.
Claim 3
Dependent Claim
39 words
A process according to claim 1, wherein at least one double tuyere is used, to the inner circuit of which is supplied a mixture of the diluent fluid and oxidising fluid physically distinct and separate from said third flow.
Claim 4
Dependent Claim
50 words
A process according to claim 1, wherein at least one triple tuyere is used and the oxidizing fluid and the diluent fluid are introduced separately into and maintained physically distinct and separate in two separate inner circuits of each triple tuyere and physically distinct and separate from said third flow.
Claim 5
Dependent Claim
68 words
A process according to claim 3, wherein a primary flow of the oxidising fluid is supplied to the centre of the tuyere, a secondary flow of the diluent fluid is supplied in a separate circuit around the primary flow, and a tertiary flow of the hydro-carbon containing liquid is supplied to the periphery of said tuyere the three flows being maintained physically distinct and separate in said tuyere.
Claim 6
Dependent Claim
67 words
A process according to claim 3, wherein a primary flow of the diluent fluid is supplied to the centre of the tuyere, a secondary flow of the oxidising fluid is supplied in a separate circuit around the primary flow, and a tertiary flow of the hydro-carbon containing liquid is supplied to the periphery of said tuyere said flows being maintained physically distinct and separate in said tuyere.
Claim 7
Dependent Claim
14 words
A process according to claim 1, wherein the oxidising fluid is industrially pure oxygen.
Claim 8
Dependent Claim
15 words
A process according to claim 1, wherein the oxidising fluid is air or oxygen-enriched air.
Claim 9
Dependent Claim
14 words
A process according to claim 1, wherein the diluent fluid is an inert gas.
Claim 10
Dependent Claim
12 words
A process according to claim 8, wherein the inert gas is argon.
Claim 11
Dependent Claim
24 words
A process according to claim 1, wherein the diluent fluid dissociates or reacts to produce a diluent gas on contact with the molten metal.
Claim 12
Dependent Claim
17 words
A process according to claim 10, wherein the diluent fluid supplied to the tuyere is water vapour.
Claim 13
Dependent Claim
24 words
A process according to claim 10, wherein the diluent fluid supplied to the tuyere is a spray of water droplets in a vehicle gas.
Claim 14
Dependent Claim
53 words
A process according to claim 1, wherein the steel is refined in two stages, and in the first stage the flow of diluent fluid is zero, being replaced by an oxidising fluid flow, and, in the second stage, the diluent fluid flow increases until it is more than twice the oxidising fluid flow.
Claim 15
Dependent Claim
45 words
A process according to claim 13, wherein the carbon content of the molten metal at the end of the first stage is from 0.150 to 0.600 percent, the molten metal temperature is approximately 1,600*C and the chromium content of the metal is approximately 18 percent.
Claim 16
Dependent Claim
25 words
A process according to claim 14, wherein the carbon content of the molten metal at the end of the first stage is approximately 0.4 percent.
Claim 17
Dependent Claim
14 words
A process according to claim 1, wherein the hydro-carbon containing liquid is fuel oil.
Claim 18
Dependent Claim
32 words
A process according to claim 1, wherein the carbon make-up liquid is an emulsion of a component selected from the group consisting of argon, water vapour and water droplets in fuel oil.
Claim 19
Dependent Claim
33 words
A process according to claim 16, wherein the proportion by weight of fuel oil flow relative to oxygen flow rate is controlled during the refining operation and is from 1 to 10 percent.
Claim 20
Dependent Claim
16 words
A process according to claim 18, wherein the said proportion is from 2.5 to 4 percent.
Claim 21
Dependent Claim
16 words
A process according to claim 1, which is Performed in vacuo or at a reduced pressure.
Claim 22
Dependent Claim
13 words
A process according to claim 1, wherein the alloy steel is stainless steel.
References Cited (Backward Citations)
US3003865A
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US3046107A
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US3330645A
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US3556773A
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US3706549A
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US3725041A
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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) | 1977-10-28 | 1978-04-29 | 1978-10-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-28 | 1982-04-29 | 1982-10-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-28 | 1986-04-29 | 1986-10-29 | $7700.00 | Window Closed / Lapsed |