US4160664A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing ultra-low carbon stainless steel
Assignee: Nippon Steel Nisshin Co Ltd
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Filing: 1978-01-13
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Granted: 1979-07-10
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Expires: 1998-01-13
Abstract
Abstract A process for producing an ultra-low carbon stainless steel, which comprises preparing a molten metal of low carbon stainless steel by means of top-blowing of oxygen onto the surface of said molten metal contained in a vessel under reduced pressure, and while maintaining said molten metal under reduced pressure, blowing a mixed gas of an oxidizing gas and an inert gas into the low carbon stainless steel molten metal through a lance immersed in the melt.
Inventors
- 👤 Shigeaki Maruhashi
- 👤 Yoshio Kobayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:27
CPC Classifications
C; C21; C21C; C21C7/00; C21C7/04; C21C7/068; C21C7/0685; C21C7/10
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
76 words
A process for producing an ultra-low carbon stainless steel which comprises preparing a molten metal melt of low carbon stainless steel by top-blowing an oxidizing gas onto the surface of said molten metal contained in a vessel under reduced pressure, and while maintaining said molten metal under reduced pressure, blowing a mixed gas of an oxidizing gas and an inert gas into the low carbon stainless steel molten metal through a lance immersed in the melt.
Claim 2
Dependent Claim
76 words
A process for producing an ultra-low carbon stainless steel which comprises preparing a molten metal melt of low carbon stainless steel by top-blowing an oxidizing gas onto the surface of said molten metal contained in a vessel under reduced pressure, and while maintaining said molten metal under reduced pressure, blowing a mixed gas of an oxidizing gas and an inert gas into the low carbon stainless steel molten metal through a lance immersed in the melt.
Claim 3
Dependent Claim
35 words
A process according to claim 1, in which the mixing ratio of the oxidizing gas and the inert gas is controlled so that the ratio of V co /(V co +V) is less than 0.7.
Claim 4
Dependent Claim
39 words
A process according to claim 1, in which the carbon content of said low carbon stainless steel is in the range of from 0.01 to 0.02%, and the carbon content of said ultra-low carbon stainless steel is below 0.01%.
Claim 5
Dependent Claim
50 words
A process according to claim 1, in which the said low carbon stainless steel is prepared by blowing said oxidizing gas onto the surface of the molten metal through a lance, then immersing the lance in the melt and blowing said mixed gas into the melt through the immersed lance.
Claim 6
Dependent Claim
21 words
A process according to claim 1, in which said oxidizing gas is oxygen gas and said inert gas is argon gas.
Claim 7
Dependent Claim
98 words
A process for producing an ultra-low carbon stainless steel, which comprises preparing a molten metal melt of low carbon stainless steel top-blowing an oxidizing gas onto the surface of said molten metal contained in a vessel under reduced pressure, bubbling said molten metal by introducing an inert gas into the melt from the bottom of said vessel, and while maintaining said molten metal under reduced pressure and bubbling said molten metal, blowing a mixed gas of an oxidizing gas and an inert gas into the low carbon stainless steel molten metal through a lance immersed in the melt.
Claim 8
Dependent Claim
98 words
A process for producing an ultra-low carbon stainless steel, which comprises preparing a molten metal melt of low carbon stainless steel top-blowing an oxidizing gas onto the surface of said molten metal contained in a vessel under reduced pressure, bubbling said molten metal by introducing an inert gas into the melt from the bottom of said vessel, and while maintaining said molten metal under reduced pressure and bubbling said molten metal, blowing a mixed gas of an oxidizing gas and an inert gas into the low carbon stainless steel molten metal through a lance immersed in the melt.
Claim 9
Dependent Claim
35 words
A process according to claim 6, in which the mixing ratio of the oxidizing gas and the inert gas is controlled so that a ratio of V co /(V co +V) is less than 0.7.
Claim 10
Dependent Claim
39 words
A process according to claim 6, in which the carbon content of said low carbon stainless steel is in the range of from 0.01 to 0.02%, and the carbon content of said ultra-low carbon stainless steel is below 0.01%.
Claim 11
Dependent Claim
49 words
A process according to claim 6, in which said low carbon stainless steel is prepared by blowing said oxidizing gas onto the surface of the molten metal through a lance, then immersing the lance in the melt and blowing said mixed gas into the melt through the immersed lance.
Claim 12
Dependent Claim
21 words
A process according to claim 6, in which said oxidizing gas is oxygen gas and said inert gas is argon gas.
References Cited (Backward Citations)
US3953199A
Cited
US3854932A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-07-09 | 1983-01-08 | 1983-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-07-09 | 1987-01-08 | 1987-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-07-09 | 1991-01-08 | 1991-07-10 | $7700.00 | Window Closed / Lapsed |