US3982927A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of blowing to obtain a very low amount of carbon in chrome steels
Assignee: Creusot Loire SA
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Filing: 1975-01-23
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Granted: 1976-09-28
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Expires: 1995-01-23
Abstract
Abstract Chromium-containing steels are decarburised without substantial losses of chromium by blowing simultaneously into the molten steels, below the surface thereof, water vapor and a non-oxidising gas such as hydrogen, nitrogen, argon or helium. A triple feed tuyere is used, with the water vapor in the central or intermediate tube, and the non-oxidizing gas in the other inner tube, and with a protective fluid in the outer tube. The proportions of water vapor and non-oxidizing gas are selected so that the temperature of the steel bath is thereby controlled and also the desired decarburisation occurs without substantial chromium loss.
Inventors
- 👤 Jean Saleil
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:21
CPC Classifications
C; C21; C21C; C21C7/00; C21C7/04; C21C5/00; C21C5/005; C21C7/068
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
101 words
A method of refining a chromium-containing steel which comprises the steps of separately and simultaneously blowing into the steel, below its surface, controlled amounts of water vapour and a non-oxidizing gas to reduce loss of chromium, to reduce the carbon content of the steel to less than 0.015%, and to control the temperature of the bath, the water vapour and non-oxidizing gas each being blown into the steel through one of the two inner tubes of a nozzle comprising three concentric tubes, and a fluid for protecting the nozzle against wear is blown into the steel through the outer concentric tube.
Claim 2
Independent Claim
101 words
A method of refining a chromium-containing steel which comprises the steps of separately and simultaneously blowing into the steel, below its surface, controlled amounts of water vapour and a non-oxidizing gas to reduce loss of chromium, to reduce the carbon content of the steel to less than 0.015%, and to control the temperature of the bath, the water vapour and non-oxidizing gas each being blown into the steel through one of the two inner tubes of a nozzle comprising three concentric tubes, and a fluid for protecting the nozzle against wear is blown into the steel through the outer concentric tube.
Claim 3
Dependent Claim
13 words
A method according to the claim 1, wherein the non-oxidising gas is hydrogen.
Claim 4
Dependent Claim
25 words
A method according to the claim 1, wherein the non-oxidising gas is a neutral gas selected from the group consisting of nitrogen, argon and helium.
Claim 5
Dependent Claim
30 words
A method according to the claim 3, wherein the non-oxidising gas is nitrogen and its flow rate produces chrome-steels with a nitrogen content on the order of 0.100% to 0.250%.
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) | 1979-09-28 | 1980-03-29 | 1980-09-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-09-28 | 1984-03-29 | 1984-09-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-09-28 | 1988-03-29 | 1988-09-28 | $7700.00 | Window Closed / Lapsed |