Surface diffusion hardening of metals in fused salt bath - by injecting diffusing element as gaseous cpd. into the bath

    公开(公告)号:FR2416272A1

    公开(公告)日:1979-08-31

    申请号:FR7803726

    申请日:1978-02-03

    Applicant: SERVIMETAL

    Abstract: In a method of diffusing one or more elements into a metal surface by immersing the metal in a fused salt bath into which the element(s) is introduced as a compound in the gaseous or vapour state or is liberated by pyrolyis of the cpd., the cpd. introduced in admixture with an inert gas in the form of fine bubbles. The method is es. useful for carburising, nitriding, carbonitriding, sulphidising or boridising steel and other metals such as Ti and Zr. It avoids toxic cpds. (cyanides) in the bath, makes use of molten alkali (ne earth) halides which are removed easily from metal surfaces, improves control of carburising potential, gives surface hardnesses of >700 HV in small steel components after oil quenching, consumes less of the diffusing element, has low investment and maintenance costs, avoids salt regeneration and solid waste disposal problems, and gives more flexible operation (e.g. preheating and surface diffusion can be carried out in the same bath as well as successive different surface diffusion processes). Residual carbon in the bath, can be easily removed, e.g. by passing air or oxygen through the bath.

    50.
    发明专利
    未知

    公开(公告)号:NO155396B

    公开(公告)日:1986-12-15

    申请号:NO802511

    申请日:1980-08-22

    Applicant: SERVIMETAL

    Abstract: The invention concerns an apparatus for active filtration and treatment of liquid metals and alloys and particularly to the purification of aluminum, magnesium, or alloys based on aluminum or magnesium, prior to molding. It comprises a detachable cartridge, closed at at least one end by a porous block based on grains of fritted flux and filled with grains of flux, solid at the temperature of the metal to be filtered. The cartridge may include a means for injecting an active or inert gas into the grains; it may be arranged in a heated, heat insulated ladle.

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