Emploi du vide lors du traitement thermique des metaux

Jean-Jacques Huet

    Research outputpeer-review


    The vacuum heat treatment of metals brings new possibilities to the metallurgy. Vacuum is a very pure inert atmosphere; indeed, the partial pressure of gaseous impurities may be orders of magnitude lower than the one existing in inert gases, even if they are carefully purified. Moreover, a dynamic vacuum allows the
    evacuation of volatile compounds present in the pieces undergoing heat treatment. It is so possible to outgas very effectively a great number of metals ; aluminium, steels, electrolytic nickel...
    Vacuum heat treatments can be done on finished or nearly finished pieces practically without modification of the surface of the treated material. This is the case for instance for nickel base refractory alloys. If the vacuum heat treatment is interesting for the common metals, the technique has been largely developped for the less common metals, generally very reactive with the atmospheric gases. For these new metals, an inert atmosphere is an absolute necessity. Nevertheless, the use of vacuum has its limits. All the mechanisms installed inside the furnaces are more complicated and, for instance, there are limited possibilities for quenching. Large losses of metals are recorded when their vapour pressure at the working temperature is higher than the pressure of the laboratory of the furnace. Vacuum promotes also reaction by contact between two stable compounds which may give volatile compounds. Finally, the vacuum quality has a very big influence when very reactive metals are treated and when a very high purity is needed.
    Original languageEnglish
    PublisherSCK CEN
    Number of pages13
    StatePublished - Jun 1965

    Publication series

    NameSCK CEN Reports
    PublisherSCK CEN

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