US3885958A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of producing chromium containing alloys
Assignee: Sandvik AB
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Filing: 1973-12-21
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Granted: 1975-05-27
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Expires: 1993-12-21
Abstract
Abstract A chromium-containing alloy, having very low contents of nitrogen and carbon, is produced by refining with a small but effective addition of aluminum, or an aluminum alloy, preferably an aluminum-lithium alloy.
Inventors
- 👤 Gunnar Grunbaum
- 👤 John Erik Wallen
- 👤 John Kjell Gustafsson
- 👤 Gustaf Widmark
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 19:25
CPC Classifications
C; C22; C22C; C22C33/00; C22C33/04
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
123 words
METHOD OF PRODUCING A CHRONIUM-CONTAINING ALLOY HAVING VERY LOW CONTENTS OF NITROGEN AND CARBON NOT AMOUNTING IN TO TOO MORE THAN 0.01 PERCENT BY WEIGHT, WHICH COMPRISES MELTING A CHARGE CONTAINING AT LEAST 1 PERCENT BY WEIGHT OF CARBON AND CONSISTING ESSENTIALLY OF A CHRONIUM-CONTAINING INITIAL MATERIAL TOGETHER WITH A BASE METAL AND DESIRED ALLOYING ELEMENTS; ADDING TO THE MELT A NITRIDABLE MEMBER OF THE GROUP CONSISTING OF ALUMINIUM AND ALUMINIUM ALLOYS, IN AN AMOUNT CORRESPONDING TO AT LEAST 3 PERCENT BY WEIGHT OF SAID MELT THEREBY CONVERTING NITROGEN TO ALUMINIUM NITRIDE IN THE FORM OF A CONSTITUENT OF THE RESULTING SLAG; AND THEREAFTER REFINING THE MOLTEN CHARGE BY OXIDIZING CARBON AND RESIDUAL ALLIMINUM AND REMOVING SLAG CONTAINING ALUMINUM NITRIDE AND ALUMINUM OXIDE.
Claim 2
Dependent Claim
123 words
METHOD OF PRODUCING A CHRONIUM-CONTAINING ALLOY HAVING VERY LOW CONTENTS OF NITROGEN AND CARBON NOT AMOUNTING IN TO TOO MORE THAN 0.01 PERCENT BY WEIGHT, WHICH COMPRISES MELTING A CHARGE CONTAINING AT LEAST 1 PERCENT BY WEIGHT OF CARBON AND CONSISTING ESSENTIALLY OF A CHRONIUM-CONTAINING INITIAL MATERIAL TOGETHER WITH A BASE METAL AND DESIRED ALLOYING ELEMENTS; ADDING TO THE MELT A NITRIDABLE MEMBER OF THE GROUP CONSISTING OF ALUMINIUM AND ALUMINIUM ALLOYS, IN AN AMOUNT CORRESPONDING TO AT LEAST 3 PERCENT BY WEIGHT OF SAID MELT THEREBY CONVERTING NITROGEN TO ALUMINIUM NITRIDE IN THE FORM OF A CONSTITUENT OF THE RESULTING SLAG; AND THEREAFTER REFINING THE MOLTEN CHARGE BY OXIDIZING CARBON AND RESIDUAL ALLIMINUM AND REMOVING SLAG CONTAINING ALUMINUM NITRIDE AND ALUMINUM OXIDE.
Claim 3
Dependent Claim
18 words
Method according to claim 1, wherein the melt has a content of Cr between 15 and 30 percent.
Claim 4
Dependent Claim
21 words
Method according to claim 1, in which the melt is heated to a temperature between 1,3001,500* C., before Al is added.
Claim 5
Dependent Claim
33 words
Method according to claim 1, wherein the added aluminum is in the form of an alloy consisting essentially of Al and a member of the group consisting of Li, Ba, Ca and Mg.
Claim 6
Dependent Claim
26 words
Method according to claim 4, in which carbon and aluminum remaining in the melt after the nitrogen refining operation are removed from the melt by oxidation.
Claim 7
Dependent Claim
24 words
Method according to claim 5, in which the oxidation of carbon and aluminum is effected with the aid of added chromium ore or scrap.
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) | 1978-05-26 | 1978-11-25 | 1979-05-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-26 | 1982-11-25 | 1983-05-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-26 | 1986-11-25 | 1987-05-27 | $7700.00 | Window Closed / Lapsed |