New Alloying Systems for Sintered Steels: Critical Aspects of Sintering Behavior
Autor: | José Manuel Torralba, Herbert Danninger, Christian Gierl-Mayer, Raquel Oro, Mónica Campos |
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Rok vydání: | 2014 |
Předmět: |
Sintered Steels
Inert Materiales Decarburization Materials science Alloy Metallurgy Metals and Alloys Sintering chemistry.chemical_element Química engineering.material Condensed Matter Physics Oxygen Methane Iron powder Thermogravimetry chemistry.chemical_compound Sintering behavior chemistry Mechanics of Materials engineering |
Zdroj: | e-Archivo. Repositorio Institucional de la Universidad Carlos III de Madrid instname |
ISSN: | 1543-1940 1073-5623 |
Popis: | Oxygen-sensitive alloying elements such as Mn, Si, and Cr have a high potential for improving the properties of low alloyed sintered steels while reducing the alloying cost. However, it is necessary to find a way for avoiding, or at least minimizing, the oxidation of these elements especially during the early stages of the sintering cycle. In this study Mn, Si, and Cr were introduced in the form of a master alloy powder designed to be mixed with the iron base powder and provide the final composition of the steel during the sintering process. The reduction/oxidation phenomena taking place during the heating stage were studied by thermogravimetry, dilatometry, and mass spectroscopy, using either reducing (H2) or inert (Ar) atmospheres. The results show how the difference in chemical activity between base iron powder and master alloy causes the so called "internal-getter" effect, by which the reduction of less stable iron oxides leads to oxidation of the elements with higher affinity for oxygen. This effect can be somehow minimized when sintering in H2, since the iron oxides are reduced at lower temperatures at which the reactivity of the elements in the master alloy is lower. However, H2 concentration in the processing atmosphere needs to be carefully adapted to the specific composition of the materials being processed in order to minimize decarburization by methane formation during sintering. Höganäs AB Sweden, financial support provided through the Höganäs Chair IV Publicado |
Databáze: | OpenAIRE |
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