Invention Grant
- Patent Title: Processes for producing low nitrogen metallic chromium and chromium-containing alloys and the resulting products
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Application No.: US14533741Application Date: 2014-11-05
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Publication No.: US10041146B2Publication Date: 2018-08-07
- Inventor: Kleber A. Sernik , Alaercio Salvador Martins Vieria , Adriano Porfirio Rios , Daniel Pallos Fridman
- Applicant: Companhia Brasileira de Metalurgia e Mineração
- Applicant Address: BR Araxá
- Assignee: Companhia Brasileira de Metalurgia e Mineraçäo
- Current Assignee: Companhia Brasileira de Metalurgia e Mineraçäo
- Current Assignee Address: BR Araxá
- Agency: Locke Lord LLP
- Agent Alicia J. Carroll
- Main IPC: C22B34/32
- IPC: C22B34/32 ; C22B5/04 ; C22B9/04 ; C22C19/05 ; C22C1/04 ; C22C1/06 ; C22C27/06

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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