Patent US3208844A successfully refreshed from Google Patents.
US3208844A
Expired / Lapsed
US
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Process for producing a low-temperature tough steel
Assignee: Yawata Iron and Steel Co Ltd
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Filing: 1962-08-03
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Granted: 1965-09-28
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Expires: 1982-08-03
Abstract
No abstract record available.
Inventors
- 👤 Kato Takeshi
- 👤 Matsuda Kamematsu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 11:20
CPC Classifications
C; C21; C21C; C21C7/00; C21C7/10; C22; C22C; C22C38/00; C22C38/001
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
132 words
A PROCESS FOR PRODUCING LOW-TEMPERATURE TOUGH STEEL WHICH COMPRISES ADDING A NITRIDE TO A MOLTEN STEEL PREPARED IN AN OPEN-HEARTH FURNACE AND CONTAINING 0.15% BY WEIGHT CARBON TO RAISE THE NITROGEN CONTENT OF SAID MOLTEN STEEL TO BETWEEN ABOUT 0.008 TO ABOUT 0.04% BY WEIGHT FOR EFFECTING ARDENT FOAMING PHENOMENON DURING THE SUBSEQUENT DEGASSING TREATMENT, SUCKING UP SUCCESSIVELY A PART OF THE THUS OBTAINED MOLTEN STEEL INTO A VACUUM DEGASSIFYING VESSEL, DEGASSIFYING THE THUS SUCKED UP MOLTEN STEEL IN SAID VACUUM DEGASSIFYING VESSEL WHILE MAINTAINING A PRESSURE IN SAID VESSEL OF FROM 1 TO 40 MM. HG, SAID DEGASSIFYING REDUCING THE OXYGEN CONTENT OF SAID MOLTEN STEEL TO NOT MORE THAN 0.002% BY WEIGHT AND THE NITROGEN CONTENT TO ABOUT THAT WHICH IT WAS BEFORE ADDING NITROGEN THERETO, AND RECOVERING THE PRODUCT.
Claim 2
Dependent Claim
132 words
A PROCESS FOR PRODUCING LOW-TEMPERATURE TOUGH STEEL WHICH COMPRISES ADDING A NITRIDE TO A MOLTEN STEEL PREPARED IN AN OPEN-HEARTH FURNACE AND CONTAINING 0.15% BY WEIGHT CARBON TO RAISE THE NITROGEN CONTENT OF SAID MOLTEN STEEL TO BETWEEN ABOUT 0.008 TO ABOUT 0.04% BY WEIGHT FOR EFFECTING ARDENT FOAMING PHENOMENON DURING THE SUBSEQUENT DEGASSING TREATMENT, SUCKING UP SUCCESSIVELY A PART OF THE THUS OBTAINED MOLTEN STEEL INTO A VACUUM DEGASSIFYING VESSEL, DEGASSIFYING THE THUS SUCKED UP MOLTEN STEEL IN SAID VACUUM DEGASSIFYING VESSEL WHILE MAINTAINING A PRESSURE IN SAID VESSEL OF FROM 1 TO 40 MM. HG, SAID DEGASSIFYING REDUCING THE OXYGEN CONTENT OF SAID MOLTEN STEEL TO NOT MORE THAN 0.002% BY WEIGHT AND THE NITROGEN CONTENT TO ABOUT THAT WHICH IT WAS BEFORE ADDING NITROGEN THERETO, AND RECOVERING THE PRODUCT.
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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) | 1968-09-27 | 1969-03-29 | 1969-09-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1972-09-27 | 1973-03-29 | 1973-09-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1976-09-27 | 1977-03-29 | 1977-09-28 | $7700.00 | Window Closed / Lapsed |