US3892597A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of nitriding
Assignee: Surface Combustion Corp
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Filing: 1973-11-01
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Granted: 1975-07-01
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Expires: 1993-11-01
Abstract
Abstract A process for the nitriding of ferrous work utilizing a carrier gas consisting essentially of nitrogen with controlled low quantities of hydrogen. A ductile, wear resistant, hardened part is obtained by nitriding with a carrier gas containing 2-4 percent hydrogen, the balance being nitrogen, to which ammonia gas is added in quantities sufficient to prevent more than 10 percent hydrogen being present. Additionally, the ferrous parts are treated over a relatively short period of time, thereby obtaining a thin iron nitride layer on the surface of the work.
Inventors
- 👤 Joseph A Lincoln
- 👤 Iii Joseph A Riopelle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 13:45
CPC Classifications
C; C23; C23C; C23C8/00; C23C8/06; C23C8/08; C23C8/24; C23C8/26
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
168 words
A PROCESS FOR NITRIDING FERROUS PARTS TO PRODUCE A THIN COMPOUND LAYER OF COMPLEX NITRIDES CONTAINING PRINCIPALLY EPSILON PHASE WITHOUT THE PRESENCE OF FE4N COMPRISING THE STEPS OF: PLACING SAID PARTS IN A FURNACE CONTAINING AN ATMOSPHERE DEFINED AS A NONCOMBUSTIBLE CARRIER GAS CONSISTING ESSENTIALLY OF 95-97 PERCENT NITROGEN, 1/2 TO 1 1/2 PERCENT CARBON MONOXIDE AND 2-4 PERCENT HYDROGEN, HEATING SAID PARTS TO AN APPROXIMATE TEMPERATURE 1,000*F, INTRODUCING AMMONIA GAS TO SAID CARRIER GAS TO FORM A NITRIDING ATMOSPHERE WITHIN THE FURNACE , SAID NITRIDING ATMOSPHERE CONTAINING 5-25 PERCENT AMMONIA GAS BY VOLUME, MAINTAINING THE HYDROGEN GAS IN SAID NITRIDING ATMOSPHERE AT A VALUE NO GREATER THAN 10 PERCENT BY VOLUME IN SAID NITRIDING ATMOSPHRE BY INTRODUCING ADDITIONAL QUANTITIES OF CARRIER GAS WHILE WITHDRAWING PORTIONS OF SAID NITRIDING ATMOSPHERE, AND SUBJECTING SAID PARTS TO SAID NITRIDING ATMOSPHERE FOR A PERIOD BETWEEN 1/2 TO 10 HOURS UNTIL A COMPOUND LAYER OF APPROXIMATELY 0.0005 INCH THICKNESS AND COMPOSED PRINCIPALLY OF EPSILON PHASE EXISTS AT THE SURFACE OF SAID PARTS.
Claim 2
Dependent Claim
168 words
A PROCESS FOR NITRIDING FERROUS PARTS TO PRODUCE A THIN COMPOUND LAYER OF COMPLEX NITRIDES CONTAINING PRINCIPALLY EPSILON PHASE WITHOUT THE PRESENCE OF FE4N COMPRISING THE STEPS OF: PLACING SAID PARTS IN A FURNACE CONTAINING AN ATMOSPHERE DEFINED AS A NONCOMBUSTIBLE CARRIER GAS CONSISTING ESSENTIALLY OF 95-97 PERCENT NITROGEN, 1/2 TO 1 1/2 PERCENT CARBON MONOXIDE AND 2-4 PERCENT HYDROGEN, HEATING SAID PARTS TO AN APPROXIMATE TEMPERATURE 1,000*F, INTRODUCING AMMONIA GAS TO SAID CARRIER GAS TO FORM A NITRIDING ATMOSPHERE WITHIN THE FURNACE , SAID NITRIDING ATMOSPHERE CONTAINING 5-25 PERCENT AMMONIA GAS BY VOLUME, MAINTAINING THE HYDROGEN GAS IN SAID NITRIDING ATMOSPHERE AT A VALUE NO GREATER THAN 10 PERCENT BY VOLUME IN SAID NITRIDING ATMOSPHRE BY INTRODUCING ADDITIONAL QUANTITIES OF CARRIER GAS WHILE WITHDRAWING PORTIONS OF SAID NITRIDING ATMOSPHERE, AND SUBJECTING SAID PARTS TO SAID NITRIDING ATMOSPHERE FOR A PERIOD BETWEEN 1/2 TO 10 HOURS UNTIL A COMPOUND LAYER OF APPROXIMATELY 0.0005 INCH THICKNESS AND COMPOSED PRINCIPALLY OF EPSILON PHASE EXISTS AT THE SURFACE OF SAID PARTS.
References Cited (Backward Citations)
US2452915A
Cited
US3399085A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-06-30 | 1978-12-30 | 1979-07-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-30 | 1982-12-30 | 1983-07-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-30 | 1986-12-30 | 1987-07-01 | $7700.00 | Window Closed / Lapsed |