Abstract: Apparatus for producing metal powders by atomization, the apparatus including melting means for melting the material to be atomized, an atomizing enclosure in which a dispersion head rotating at high speed is disposed to scatter the molten material in atomized form, means for cooling the atomized material and the head, and means for collecting the cooled powder material obtained in this way, said melting means including at least one vertical inductive plasma furnace producing an envelope of plasma-generating gases containing the top face of the dispersion head, and said cooling means comprising both a first series of members for dispensing a cooling fluid disposed in the top portion of the atomizing enclosure to create a cold zone at the periphery of the envelope, and a second series of members for circulating a cooling fluid disposed in the bottom portion of the enclosure to create a cold zone at the bottom face of the head.

Abstract: A low pressure carburization process for metal alloy parts uses a fuel mixture consisting of hydrogen with 2 to 60% by volume ethylene. The fuel mixture is heated to a temperature between 820.degree. and 1100.degree. C. A furnace installation for carrying out the process includes a double vacuum tank or vessel arrangement with internal carburizing gas distribution, an annular space surrounding the vessel, a cover, thermocouples and a microcomputer control arrangement.

Abstract: The invention relates to a method for chromizing metallic pieces such as steel pieces and to chromized metallic pieces obtained thereby, said metallic pieces, particularly steel, comprising a chromized surface layer with a hardness at least equal to 1200 Vickers degrees and a thickness at least equal to 12 microns as well as an adjacent sub-layer with a hardness less than that of the core of said piece. The chromized surface layer has a depth preferably at least equal to 20 microns, more preferably 30 microns, and the hardness of the sublayer presents a maximum variation of 25 Vickers degrees with respect to that of the core of said piece.