US3140205A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for nitriding steels of the low, medium and high alloy types by first removing the passive oxide surface film
Assignee: CHAPMAN DIVISION CRANE CO
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Filing: 1962-07-26
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Granted: 1964-07-07
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Expires: 1982-07-26
Abstract
No abstract record available.
Inventors
- 👤 Vincent T Malcolm
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:37
CPC Classifications
C; C23; C23C; C23C8/00; C23C8/02; C23C8/06; C23C8/08; C23C8/24; C23C8/26
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
102 words
THE IMPROVEMENT IN THE HARDENING OF THE SURFACE OF A METALLIC WORK PIECE CHARACTERIZED BY THE PRESENCE ON THE SURFACE THEREOF A PASSIVE FILM ACTING TO INHIBIT PENETRATION OF NITROGEN INTO THE SURFACE WHEN SUCH WORK PIECE IS HEATED IN A NITROGENOUS ATMOSPHERE COMPRISNG, HEATING THE WORK PIECE AT A TEMPERATURE BETWEEN 400* AND 700* F. DURING A TIME INTERVAL OF AT LEAST 2 HOURS DURATION IN THE PRESENCE OF THE GASEOUS PRODUCTS OF A DECOMPOSED POLYVINYL CHLORIDE RESIN AND SUBSEQUENTLY AT A TEMPERATURE OF 1000*F. DURING A TIME INTERVAL OF APPROXIMATELY 20 HOURS DURATION IN THE PRESENCE OF A NITROGEN-LIBERATING GAS.
Claim 2
Dependent Claim
102 words
THE IMPROVEMENT IN THE HARDENING OF THE SURFACE OF A METALLIC WORK PIECE CHARACTERIZED BY THE PRESENCE ON THE SURFACE THEREOF A PASSIVE FILM ACTING TO INHIBIT PENETRATION OF NITROGEN INTO THE SURFACE WHEN SUCH WORK PIECE IS HEATED IN A NITROGENOUS ATMOSPHERE COMPRISNG, HEATING THE WORK PIECE AT A TEMPERATURE BETWEEN 400* AND 700* F. DURING A TIME INTERVAL OF AT LEAST 2 HOURS DURATION IN THE PRESENCE OF THE GASEOUS PRODUCTS OF A DECOMPOSED POLYVINYL CHLORIDE RESIN AND SUBSEQUENTLY AT A TEMPERATURE OF 1000*F. DURING A TIME INTERVAL OF APPROXIMATELY 20 HOURS DURATION IN THE PRESENCE OF A NITROGEN-LIBERATING GAS.
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) | 1967-07-07 | 1968-01-06 | 1968-07-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1971-07-07 | 1972-01-06 | 1972-07-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1975-07-07 | 1976-01-06 | 1976-07-07 | $7700.00 | Window Closed / Lapsed |