US3756870A
Expired / Lapsed
US
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Induction heating method of case hardening carbon steel rod
Assignee: Park Ohio Holdings Corp
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Filing: 1971-05-10
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Granted: 1973-09-04
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Expires: 1991-05-10
Abstract
Abstract A METHOD OF CASE HARDENING TO A DESIRED DEPTH A ROD FORMED FROM CARBON STEEL WHICH METHOD INCLUDES THE STEPS OF MOVING THE ROD LONGITUDINALLY, INDUCTIVELY HEATING THE ROD AT A RATE THAT CREATES A HEAT PROFILE WITHIN THE ROD WHICH PROFILE EXCEEDS THE UPPER CRITICAL HEATING TRANSFORMATION TEMPERATURE ADJACENT THE SURFACE OF THE ROD AND TO A DEPTH GENERALLY CORRESPONDING TO THE DESIRED DEPTH TO BE HARDENED WITH THE AVERAGE TEMPERATURE OF THE HEATING PROFILE BEING LESS THAN THE LOWER CRITICAL HEATING TRANSFORMATION TEMPERATURE OF THE ROD, ALLOWING THE ROD TO SOAK, AND, THEN QUENCHING THE ROD WITHIN LESS THAN ABOUT 50 SECONDS AFTER THE HEATING STEP.
Inventors
- 👤 R Kasper
- 👤 J Snyder
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:43
CPC Classifications
C; C21; C21D; C21D9/00; C21D9/02; C21D1/00; C21D1/06; C21D1/09; C21D1/10; Y; Y02; Y02P; Y02P10/00; Y02P10/25; Y10; Y10S; Y10S148/00; Y10S148/902; Y10S148/908
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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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) | 1976-09-03 | 1977-03-05 | 1977-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-03 | 1981-03-05 | 1981-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-03 | 1985-03-05 | 1985-09-04 | $7700.00 | Window Closed / Lapsed |