Patent US3871870A successfully refreshed from Google Patents.
US3871870A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of adding rare earth metals or their alloys into liquid steel
Assignee: JFE Engineering Corp
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Filing: 1973-05-01
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Granted: 1975-03-18
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Expires: 1993-05-01
Abstract
Abstract When one or more rare earth metals or their alloys are added into liquid steel in an intermediate vessel disposed between a ladle and a mold, the resulting steel exhibits excellent impact property.
Inventors
- 👤 Hidetaro Nemoto
- 👤 Takaho Kawawa
- 👤 Hideki Sato
- 👤 Eiichi Sakamoto
- 👤 Takayuki Koyano
- 👤 Takanori Anzai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:14
CPC Classifications
C; C21; C21C; C21C7/00; C21C7/0056; B; B22; B22D; B22D11/00; B22D11/10; B22D11/11; C21C7/04; C21C7/064
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
158 words
IN A CONTINUOUS CASTING PROCESS USING A SUCCESSION OF SEPARATE LADLE, TUNDISH AND MOLD, THE STEPS COMPRISING SUBSTANTIALLY COMPLETELY DEOXIDIZING MOLTEN STEEL IN SAID LADLE BY ADDITION OF ALUMINUM, SILICON, MANGANESE OR ANY COMBINATION THEREOF; THEREAFTER POURING SAID MOLTEN STEEL INTO SAID SEPARATE TUNDISH HAVING MEANS FOR PREVENTING OXIDATION OF SAID STEEL THEREIN; ADDING A RARE EARTH METAL SELECTED FROM THE GROUP CONSISTING OF LA, CE, PR AND ND, ANY ALLOY THEREOF OR ANY COMBINATION THEREOF, IN THE RATIO OF RARE EARTH METAL TO SULFUR OT BETWEEN 1.2 AND 2.0 AND IN THE FORM OF A WIRE OF A DIAMETER OF AT LEAST 2.0 TO 4.0 MM, DEEPLY INTO SAID SUBSTANTIALLY COMPLETELY DEOXIDIZED STEEL CONTAINED IN SAID TUNDISH, WITHOUT BEING EXPOSED TO OXIDATION, SAID ADDING BEING AT THE RATE OF AT LEAST 0.05 M/SEC,AND THEREAFTER PASSING SAID MOLTEN STEEL TO SAID SEPARATE MOLD HAVING MEANS FOR PREVENTING OXIDATION THEREOF, THEREBY TO PRODUCE A STEEL HAVING IMPROVED IMPACT STRENGTH.
Claim 2
Dependent Claim
158 words
IN A CONTINUOUS CASTING PROCESS USING A SUCCESSION OF SEPARATE LADLE, TUNDISH AND MOLD, THE STEPS COMPRISING SUBSTANTIALLY COMPLETELY DEOXIDIZING MOLTEN STEEL IN SAID LADLE BY ADDITION OF ALUMINUM, SILICON, MANGANESE OR ANY COMBINATION THEREOF; THEREAFTER POURING SAID MOLTEN STEEL INTO SAID SEPARATE TUNDISH HAVING MEANS FOR PREVENTING OXIDATION OF SAID STEEL THEREIN; ADDING A RARE EARTH METAL SELECTED FROM THE GROUP CONSISTING OF LA, CE, PR AND ND, ANY ALLOY THEREOF OR ANY COMBINATION THEREOF, IN THE RATIO OF RARE EARTH METAL TO SULFUR OT BETWEEN 1.2 AND 2.0 AND IN THE FORM OF A WIRE OF A DIAMETER OF AT LEAST 2.0 TO 4.0 MM, DEEPLY INTO SAID SUBSTANTIALLY COMPLETELY DEOXIDIZED STEEL CONTAINED IN SAID TUNDISH, WITHOUT BEING EXPOSED TO OXIDATION, SAID ADDING BEING AT THE RATE OF AT LEAST 0.05 M/SEC,AND THEREAFTER PASSING SAID MOLTEN STEEL TO SAID SEPARATE MOLD HAVING MEANS FOR PREVENTING OXIDATION THEREOF, THEREBY TO PRODUCE A STEEL HAVING IMPROVED IMPACT STRENGTH.
Claim 3
Dependent Claim
39 words
Process of claim 1, wherein said wire is added at the rate of 0.03% per ton of said molten steel and at the speed of addition of 0.10 m/sec with the rate of casting being at about 1.24 t/min.
Claim 4
Dependent Claim
14 words
Process of claim 1, wherein cerium is used and the cerium/sulfur ratio is 1.5.
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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) | 1978-03-17 | 1978-09-16 | 1979-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-17 | 1982-09-16 | 1983-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-17 | 1986-09-16 | 1987-03-18 | $7700.00 | Window Closed / Lapsed |