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Granges Nyby Ab

Claes Tornberg

Christer Aslund

Hans Eriksson

The invention relates to the production of a metallic powder consisting of surface-fissured, so-called irregular particles, namely a water-atomised metallic powder. The aim of the invention is to obtain an irregular surface form of powder grains () in a narrow weight class and to impart a high porosity with a homogeneous distribution to the sintered body. To this end, in a first step, the pouring stream () is deviated in its flow direction and is enlarged on its surface, and in a second step, the surface-enlarged pouring stream () is deviated again its flow direction and is divided, and the liquid metallic particles () formed are accelerated, and in a third step, the displaced liquid metallic particles () are applied and divided, at an angle &#x3b3; of between 10 and 90&#xb0; in relation to the displacement direction of the same, with a high speed current () formed at least partially from a liquid medium, and the particles () are then solidified. According to one embodiment of the invention, in order to reduce the overheating of the metal melt and/or to improve the quality of the metallic powder produced, the pouring stream () is deviated in its flow direction and a surface enlargement of the same () is carried out, in a first method step, and/or the surface-enlarged pouring stream () is deviated and divided, and the formed liquid metallic particles () are accelerated, in the second method step, with at least one current () formed from at least one heated gas or heated gas mixture.

Method for producing metallic powders consisting of irregular particles

A method of making pipes by powder metallurgy, in which powder of metal and/or metal alloys (17) is filled into a thin-walled casing consisting of inner pipe wall (12), outer pipe wall (11) and a bottom (13), subsequently the casing is closed on its side remote from the bottom (13) by an annular cover (14) and is subjected to a cold-isostatic pressure whereby the powder (17) is compacted within the casing to produce a solid or dimensionally stable pipe blank or compact (10), which is then hot-worked, e.g. extruded. In order to prevent thermal cracks on the inner pipe or inner pipe wall (12), especially in the region of the ends thereof, the inner pipe or inner pipe wall (12) is provided prior to hot-working on at least one end region thereof with at least one circumferentially extending bulge (15 or 16, respectively).

Method of making pipes by powder metallurgy and pipe blanks

A method of making powder-metallurgical articles, in which powder of metal and/or metal alloys is filled into a thin-walled casing, whereupon the casing is closed and subjected to cold-isostatic pressure. Thereby the powder within the casing is compacted to form a strong or, respectively, dimensionally stable article. When the casing wall includes a joining weld seam, said casing wall is provided with an elastically expandable layer in the close vicinity of the weld seam in order to prevent formation of a fold, preferably in such a way that an approximately uniform prestress is applied to the wall surface.

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Torshalla, Sweden

Claes Tornberg