Patent US2538239A successfully refreshed from Google Patents.
US2538239A
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Method for hardening cast iron
Assignee: THOMAS E PIPER
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Filing: 1947-09-20
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Granted: 1951-01-16
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Expires: 1967-09-20
Abstract
No abstract record available.
Inventors
- 👤 George B Farnsworth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 22:32
CPC Classifications
C; C23; C23C; C23C8/00; C23C8/06; C23C8/08; C23C8/20; C23C8/22; C21; C21D; C21D5/00
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
183 words
THE METHOD OF HARDENING A NON-MALLEABLE GRAY IRON CASTING WHICH COMPRISES HEATING THE CASTING TO A TEMPERATURE OF 1700* F. AT A RATE SLOW ENOUGH TO MINIMIZE EXPANSION STRESSES DUE TO HEATING, MAINTAINING THE CASTING AT SAID TEMPERATURE FOR A LENGTH OF TIME SUFFICIENT TO OPEN THE GRAIN STRUCTURE IN THE CASTING, SUCH TIME BEING LONGER FOR CASTING OF GREATER MASS AND BEING OF THE ORDER OF ONE HOUR FOR A CASTING HAVING MAXIMUM THICKNESS OF TWO INCHES, COOLING THE CASTING SLOWLY TO A TEMPERATURE BETWEEN 450* F. AND 700* F., HEATING THE CASTING WHILE AT LEAST PARTIALLY ENCLOSED IN A CARBURIZING MATERIAL TO A TEMPERATURE OF 1700* F., MAINTAINING SAID CASTING WHILE SO ENCLOSED AT SAID LATTER TEMPERATURE FOR A LENGTH OF TIME DETERMINED BY THE DEPTH TO WHICH IT IS DESIRED TO HARDEN THE CASTING, SLOWLY COOLING THE CASTING TO A TEMPERATURE SLIGHTLY OVER 450* F., REMOVING THE CASTING FROM THE CARBURIZER, HEATING THE CASTING TO A TEMPERATURE BETWEEN 1450* F. AND 1500* F., QUENCHING THE CASTING IN OIL, AND DRAWING THE CASTING AT TEMPERATURE APPROXIMATING 400* F. TO 500* F.
Claim 2
Independent Claim
183 words
THE METHOD OF HARDENING A NON-MALLEABLE GRAY IRON CASTING WHICH COMPRISES HEATING THE CASTING TO A TEMPERATURE OF 1700* F. AT A RATE SLOW ENOUGH TO MINIMIZE EXPANSION STRESSES DUE TO HEATING, MAINTAINING THE CASTING AT SAID TEMPERATURE FOR A LENGTH OF TIME SUFFICIENT TO OPEN THE GRAIN STRUCTURE IN THE CASTING, SUCH TIME BEING LONGER FOR CASTING OF GREATER MASS AND BEING OF THE ORDER OF ONE HOUR FOR A CASTING HAVING MAXIMUM THICKNESS OF TWO INCHES, COOLING THE CASTING SLOWLY TO A TEMPERATURE BETWEEN 450* F. AND 700* F., HEATING THE CASTING WHILE AT LEAST PARTIALLY ENCLOSED IN A CARBURIZING MATERIAL TO A TEMPERATURE OF 1700* F., MAINTAINING SAID CASTING WHILE SO ENCLOSED AT SAID LATTER TEMPERATURE FOR A LENGTH OF TIME DETERMINED BY THE DEPTH TO WHICH IT IS DESIRED TO HARDEN THE CASTING, SLOWLY COOLING THE CASTING TO A TEMPERATURE SLIGHTLY OVER 450* F., REMOVING THE CASTING FROM THE CARBURIZER, HEATING THE CASTING TO A TEMPERATURE BETWEEN 1450* F. AND 1500* F., QUENCHING THE CASTING IN OIL, AND DRAWING THE CASTING AT TEMPERATURE APPROXIMATING 400* F. TO 500* F.
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) | 1954-01-15 | 1954-07-17 | 1955-01-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-01-15 | 1958-07-17 | 1959-01-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-01-15 | 1962-07-17 | 1963-01-16 | $7700.00 | Window Closed / Lapsed |