SE470204B - Ways of making a high density alloy and high ductility - Google Patents

Description

However, heavy metal composites have proved less suitable as RSV materials due to insufficient toughness during rapid deformation processes. Interest has therefore recently been focused on the tough binder phase alloy. This alloy can not be made molten metallergically due to its high tendency to win and the accompanying brittleness. Therefore, a production based on powder metallergic methods has been proposed, mainly sintering or HIP: of a fine-grained mixture of the pure metal powders. Gas atomized powder has also been suggested as a possible starting powder. All experiments have focused on alloy compositions with composites with N contents between 15 and 30% and Ni and Fe contents in the ratio 7: 3, as this Ni / Fe ratio has been shown to be optimal for heavy metals from a toughness point of view. In addition, in some cases Co has been included, while elements such as Si, Mn and others have been considered a "poison". However, no particularly good RSV effect results have been reported for these alloys, probably due to the fact that the alloys have not been 100% single-phase, sufficiently pure, had a sufficiently low oxygen content (= low surface oxygen content of the powder), etc. These alloys have been prepared by sintering. The invention relates to a solution to the above and other related problems. The invention relates to a process according to the first paragraph, and it is characterized in that an alloy containing 1--70% by weight of H and / or Ta, 0-25% by weight of Fe, 0-1% by weight of Si and 0-2% by weight of Mn is prepared as a gas atomized powder of pure melt alloys. This should preferably be done in such plants, which give a fine powder grain size. In order to achieve the desired properties for beam-forming RSV (= high density, high ductility), the alloy used should suitably be single-phase. The alloy powder should suitably be prepared by a method which gives a low oxygen content, for example gas atomization. You can, for example, use an alloy with 25-40% by weight N, max 10% by weight Fe, about 0.1% by weight Si (or similar deoxidizing elements) and the rest Ni and a starting powder with high purity and low surface oxygen content. For projectile-forming RSV 30, multi-phase alloys may also be considered, ie alloys with 40-70% by weight of W. The alloys used do not use W and / or Ta as composite material, and these alloys are basically pure melt compositions. The alloy should suitably contain 50-70% by weight of Ni, preferably 55-65%. The alloy used in the process according to the invention must therefore contain 15-70% N, 0-25% Fe, 0-1% Si, 0-2% Mn + customary pollutants. Preferably the alloy should include 25-40% W, max 10% Fe and the rest Ni. (% in% by weight.) As an exemplary embodiment of alloys in process, the type according to the invention can be stated.

Alloy 1: 0.01% C, 0.05% Si, 0.05% Mn, 57% Ni, 22% Fe and 21% N; Alloy 2: 0.03% C, 0.14% Si, 0.23% Mn, 62% Ni, 9% Fe and 29% N; Alloy 3: 0.02% C, 0.12% Si, 0.16% Mn, 65% Ni, and 35% W.

The properties of these alloys can be classified as follows: Tensile strength Elongation Densite "Mpa% g / cm Alloy 1 260 54 10.4 Alloy 2 290 46 11.5 Alloy 3 320 48 12.3 Fine-grained powder of the alloy according to the invention has been prepared as a powder by gas atomization. , and preferably in such plants, which give fine powder grain size and low surface oxygen content. the compacted substances were filtered from 120 ° C and 120 ° C.

The invention thus comprises methods of production which give objects with better properties than the previously known, copper-based etc.

The procedure can be exemplified as follows: Powder metallurgical production, based on high-purity, gas-atomized powder with a low surface oxygen content and a small powder grain size.

Gas atomization in powder plants, which gives powders of the above kind.

Compaction of the powder by cold compaction, sintering or pressure sintering (HIP, sintering-HIP, etc.) to semi-finished products for further cold or hot processing, to almost finished form with some subsequent processing, or to 476 âßå 10 15 20 25 completely finished form without subsequent processing. The right of procedure according to the invention (see above) entails large performance and cost differences, compared with conventional processes.

Experiments with alloys and methods according to the invention have shown the following: The highest possible density of single-phase Ni-Fe-N alloys (ie without the presence of free W in the structure), is achieved in Fe-free or near Fe-free Ni-base alloys. After extinguishing annealing from 1200 ° C, an Fe-free alloy may contain about 40% W in solid solution. The density of such an alloy will be about 13 g / cm.

The highest possible W content, which can be achieved in a melt possible to atomize, amounts to about 65%. A Ni-65% W alloy is two-phase and gives a density of about 15.5 g / cm.

High ductility (> 30%) can be achieved with single-phase Ni-Fe-W alloys with N content of 15-40% and Ni / Fe ratio >> 7: 3 if they are manufactured powder metallurgically as below and extinguished annealed from a temperature of at least approx. 1000-1100 ° C after compaction or quick cooling in connection with compaction.

In order to achieve high ductility, a starting powder with a low surface oxygen content and a fine powder grain size is required. The manufacturing method according to the invention gives such a powder.

The invention also relates to methods of manufacturing operative parts for RSV ammunition. Alloys have been tested in the invention and it has been found that the following applies: These alloys are very well suited for such a purpose and entail a marked increase in the efficiency of such ammunition when used against armored vehicles with directed explosive action. These parts are suitably produced by means of plate encapsulation, followed by hetisostatic compaction, or by means of cold compaction or dynamic compaction (explosion compaction or punch compaction). The intention is to achieve full density.

The alloy can be used as a binder between balls of W or other heavy metal, for example in cylindrical, sleeve-shaped ammunition, or in conical parts, the latter 28 28 being produced by punch compaction or pressure turning.

The compaction can possibly be followed by sintering.

The invention can be varied in many ways within the scope of the following claims.

Claims (8)

470 204 10 15 20 25 30 Patent claim Process for producing a high-density, high-ductility Ni-base alloy, characterized in that an alloy containing 15-70% by weight of W and / or Ta, 0-25% by weight of Fe, O- 1% by weight Si and 0-2% by weight Mn, are prepared as a gas atomized powder of pure melt compositions of the alloy. 2. A method according to claim 1, characterized in that the alloy powder is prepared by a method which gives a low oxygen content. 3. A method according to claim 1 or 2, characterized in that the produced alloy in powder form is consolidated into action parts in highly efficient ammunition, such as for directed explosive action. 4. A method according to any one of the preceding claims, characterized in that the objects produced, for example the parts of action, are produced by means of sheet metal enclosure and hetisostatic compaction (HIP). Method according to one of Claims 1 to 3, characterized in that the manufactured objects, for example the parts of action, are produced by means of cold compaction, possibly followed by HIP, in order to achieve full density. 6. A method according to claim 4 or 5, characterized in that the active ingredients are prepared as blanks by hot or cold compaction of powder, and that these blanks are then formed into a final form by cold flow pressing, pressure turning and similar methods. 7. A method according to any one of claims 4-6, characterized in that the active parts are produced with the alloys as a binder between balls and fragments, which in turn contain W or other heavy metal, for example in cylindrical, tubular ammunition, or in conical ammunition parts. Method according to one or more of the preceding claims, characterized in that the objects, such as the parts of action, are produced by hot or cold compaction or by dynamic compaction (explosion or punch compaction) to full density, possibly followed by sint - ring.