US4340420A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing stainless steel
Assignee: SKF Steel Engineering AB
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Filing: 1980-10-24
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Granted: 1982-07-20
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Expires: 2000-10-24
Abstract
Abstract A method of manufacturing stainless steel comprising the steps of injecting a starting material containing chromium oxide and iron oxide into the lower portion of a reactor, said reactor containing a solid reducing agent, passing said starting material into a reduction zone within said lower portion, said reduction zone being maintained by the use of a plasma generator adjacent thereto, substantially instantaneously reducing and melting said starting material in said reduction zone, and removing the melted and reduced chromiferous product from the bottom of the reactor. The chromiferous product may then be further refined in an AOD convertor or the like.
Inventors
- 👤 Sven Santen
- 👤 John O. Edstrom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 03:06
CPC Classifications
C; C21; C21B; C21B13/00; C21B13/12; C21B13/125; C22; C22B; C22B4/00; B; B60; B60T; B60T15/00; B60T15/02; B60T15/36; B60T15/42; C21B13/006; Y; Y02; Y02P; Y02P10/00; Y02P10/10; Y02P10/134
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
127 words
A two step method of manufacturing chromium steel comprising the first step of injecting a starting material in the form of fine grains and containing chromium oxide and iron oxide into the lower portion of a reactor having an upper and a lower portion; said reactor containing a solid reducing agent, passing said starting material into a reduction zone within said lower portion, said reduction zone being maintained by the use of a plasma generator adjacent thereto, simultaneously injecting carbon and/or hydrocarbon fuel into said reduction zone, substantially instantaneously reducing and melting said starting material in said reduction zone, and removing the melted and reduced chromiferous product from the bottom of the reactor, and a second step of further refining the chromiferous product to produce chromium steel.
Claim 2
Dependent Claim
127 words
A two step method of manufacturing chromium steel comprising the first step of injecting a starting material in the form of fine grains and containing chromium oxide and iron oxide into the lower portion of a reactor having an upper and a lower portion; said reactor containing a solid reducing agent, passing said starting material into a reduction zone within said lower portion, said reduction zone being maintained by the use of a plasma generator adjacent thereto, simultaneously injecting carbon and/or hydrocarbon fuel into said reduction zone, substantially instantaneously reducing and melting said starting material in said reduction zone, and removing the melted and reduced chromiferous product from the bottom of the reactor, and a second step of further refining the chromiferous product to produce chromium steel.
Claim 3
Dependent Claim
32 words
A method according to claim 1 including the step of maintaining the temperature of the melted product in the reactor at a temperature of from about 1500° C. to about 1650° C.
Claim 4
Dependent Claim
15 words
A method according to claim 1 wherein the starting material also includes a slag former.
Claim 5
Independent Claim
23 words
A method according to claims 1, 2, or 3 wherein the starting material is blown into the reactor together with a carrier gas.
Claim 6
Dependent Claim
23 words
A method according to claim 4 wherein a portion of the reaction gas generated in the reactor is used as a carrier gas.
Claim 7
Dependent Claim
23 words
A method according to claim 4 wherein a portion of the reaction gas generated in the reactor is used as a plasma gas.
Claim 8
Dependent Claim
29 words
A method according to claim 1 wherein a portion of the silicon content of the chromiferous crude iron product is regulated by controlling the temperature level in the reactor.
Claim 9
Dependent Claim
18 words
A method according to claim 1 wherein the chromiferous product is further refined after removal from the reactor.
Claim 10
Dependent Claim
17 words
A method according to claim 8 wherein the chromiferous product is further refined in an AOD convertor.
Claim 11
Dependent Claim
14 words
A method according to claim 1 including the step of prereducing the starting material.
Claim 12
Dependent Claim
16 words
A method according to claim 1 wherein the starting material is flue-gas dust containing chromiferous materials.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-07-19 | 1986-01-18 | 1986-07-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-07-19 | 1990-01-18 | 1990-07-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-07-19 | 1994-01-18 | 1994-07-20 | $7700.00 | Window Closed / Lapsed |