US5254181A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of nitriding steel utilizing fluoriding
Assignee: Air Water Inc
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Filing: 1991-07-10
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Granted: 1993-10-19
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Expires: 2011-07-10
Abstract
Abstract This invention relates to a method for forming a uniform, deep nitride layer on and in steel works at low cost, wherein a steel work is fluorided in heated condition in an atmosphere of a mixed gas composed of fluorine gas and inert gas and, then, nitrided in heated condition in an atmosphere of nitriding gas.
Inventors
- 👤 Akira Yoshino
- 👤 Masaki Tahara
- 👤 Haruo Senbokuya
- 👤 Kenzo Kitano
- 👤 Teruo Minato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 00:33
CPC Classifications
C; C23; C23C; C23C8/00; C23C8/06; C23C8/34; C23C8/02; C23C8/08; C23C8/24; C23C8/26; C23C8/36; C23C8/38
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
43 words
A method for nitriding steel comprising fluoriding a steel work in heated condition in an atmosphere of a mixed gas composed of fluorine gas and inert gas and, then, nitriding the fluorided steel work in heated condition in an atmosphere of nitriding gas.
Claim 2
Independent Claim
43 words
A method for nitriding steel comprising fluoriding a steel work in heated condition in an atmosphere of a mixed gas composed of fluorine gas and inert gas and, then, nitriding the fluorided steel work in heated condition in an atmosphere of nitriding gas.
Claim 3
Independent Claim
45 words
A method for nitriding steel comprising fluoriding a steel work in heated condition in an atmosphere of a mixed gas composed of fluorine gas trifluoride gas and inert gas and, then, nitriding the fluorided steel work in heated condition in an atmosphere of nitriding gas.
Claim 4
Independent Claim
45 words
A method for nitriding steel comprising fluoriding a steel work in heated condition in an atmosphere of a mixed gas composed of fluorine gas trifluoride gas and inert gas and, then, nitriding the fluorided steel work in heated condition in an atmosphere of nitriding gas.
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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) | 1996-10-18 | 1997-04-19 | 1997-10-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-10-18 | 2001-04-19 | 2001-10-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-10-18 | 2005-04-19 | 2005-10-19 | $7700.00 | Window Closed / Lapsed |