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Found results for
 patents
1.
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PROCESSES FOR PRODUCING LOW NITROGEN, ESSENTIALLY NITRIDE-FREE CHROMIUM AND CHROMIUM PLUS NIOBIUM-CONTAINING NICKEL-BASED ALLOYS AND THE RESULTING CHROMIUM AND NICKEL-BASED ALLOYS
| Document Number |
02960576 |
| Status |
In Force |
| Filing Date |
2015-10-05 |
| Open to Public Date |
2016-07-14 |
| Grant Date |
2023-04-11 |
| Owner |
CBMM-COMPANHIA BRASILEIRA DE METALURGIA E MINERACAO (Brazil)
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| Inventor |
Sernik, Kleber A.
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Abstract
Processes for producing low nitrogen, essentially nitride-free chromium or chromium plus niobium-containing nickel-based alloys include charging elements or compounds which do not dissolve appreciable amounts of nitrogen in the molten state to a refractory crucible within a vacuum induction furnace, melting said elements or compounds therein under reduced pressure, and effecting heterogeneous carbon-based bubble nucleation in a controlled manner. The processes also include, upon cessation of bubble formation, adding low nitrogen chromium or a low nitrogen chromium-containing master alloy with a nitrogen content of below 10 ppm to the melt, melting and distributing said added chromium or chromium-containing master alloy throughout the melt, bringing the resulting combined melt to a temperature and surrounding pressure to permit tapping, and tapping the resulting melt, directly or indirectly, to a metallic mold and allowing the melt to solidify and cool under reduced pressure.
IPC Classes ?
- C22B 5/04 - Dry processes by aluminium, other metals, or silicon
- C22B 9/04 - Refining by applying a vacuum
- C22C 1/03 - Making non-ferrous alloys by melting using master alloys
- C22C 19/05 - Alloys based on nickel or cobalt based on nickel with chromium
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2.
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PROCESSES FOR PRODUCING LOW NITROGEN METALLIC CHROMIUM AND CHROMIUM-CONTAINING ALLOYS AND THE RESULTING PRODUCTS
| Document Number |
02960711 |
| Status |
In Force |
| Filing Date |
2015-10-05 |
| Open to Public Date |
2016-07-14 |
| Grant Date |
2023-09-26 |
| Owner |
CBMM-COMPANHIA BRASILEIRA DE METALURGIA E MINERACAO (Brazil)
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| Inventor |
- Sernik, Kleber A.
- Vieira, Alaercio Salvador Martins
- Rios, Adriano Porfirio
- Fridman, Daniel Pallos
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Abstract
Processes for producing low-nitrogen metallic chromium or chromium-containing alloys, which prevent the nitrogen in the surrounding atmosphere from being carried into the melt and being absorbed by the metallic chromium or chromium-containing alloy during the metallothermic reaction, include vacuum-degassing a thermite mixture comprising metal compounds and metallic reducing powders contained within a vacuum vessel, igniting the thermite mixture to effect reduction of the metal compounds within the vessel under reduced pressure i.e., below 1 bar, and conducting the entire reduction reaction in said vessel under reduced pressure, including solidification and cooling, to produce a final product with a nitrogen content below 10 ppm. The final products obtained, in addition to low-nitrogen metallic chromium in combination with other elements, can be used as raw materials in the manufacture of superalloys, stainless steel and other specialty steels whose final content of nitrogen is below 10 ppm.
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