EP0275774A2 - Process for preparing chromium-aluminium agglomerates for adding chromium to a melt of aluminium - Google Patents
Process for preparing chromium-aluminium agglomerates for adding chromium to a melt of aluminium Download PDFInfo
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- EP0275774A2 EP0275774A2 EP87402937A EP87402937A EP0275774A2 EP 0275774 A2 EP0275774 A2 EP 0275774A2 EP 87402937 A EP87402937 A EP 87402937A EP 87402937 A EP87402937 A EP 87402937A EP 0275774 A2 EP0275774 A2 EP 0275774A2
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- Prior art keywords
- powder
- aluminum
- weight
- chromium
- alloy
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- 229910052782 aluminium Inorganic materials 0.000 title claims abstract description 71
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 title claims abstract description 61
- 229910052804 chromium Inorganic materials 0.000 title claims abstract description 42
- 239000011651 chromium Substances 0.000 title abstract description 33
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 title abstract description 26
- 238000004519 manufacturing process Methods 0.000 title description 4
- QQHSIRTYSFLSRM-UHFFFAOYSA-N alumanylidynechromium Chemical compound [Al].[Cr] QQHSIRTYSFLSRM-UHFFFAOYSA-N 0.000 title 1
- 239000004411 aluminium Substances 0.000 title 1
- 239000000155 melt Substances 0.000 title 1
- 239000000843 powder Substances 0.000 claims abstract description 53
- 238000000034 method Methods 0.000 claims abstract description 24
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 20
- 239000000956 alloy Substances 0.000 claims abstract description 20
- 230000004927 fusion Effects 0.000 claims abstract description 5
- 239000013589 supplement Substances 0.000 claims abstract 5
- 239000011230 binding agent Substances 0.000 claims description 14
- 239000002245 particle Substances 0.000 claims description 7
- 229920001342 Bakelite® Polymers 0.000 claims description 5
- 239000004637 bakelite Substances 0.000 claims description 5
- 230000000295 complement effect Effects 0.000 claims description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical group [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims 1
- 229910052799 carbon Inorganic materials 0.000 claims 1
- 238000004090 dissolution Methods 0.000 abstract description 5
- 229910000599 Cr alloy Inorganic materials 0.000 abstract description 4
- 238000005056 compaction Methods 0.000 abstract description 4
- 238000002844 melting Methods 0.000 abstract description 3
- 230000008018 melting Effects 0.000 abstract description 3
- 229910000838 Al alloy Inorganic materials 0.000 description 4
- QRRWWGNBSQSBAM-UHFFFAOYSA-N alumane;chromium Chemical compound [AlH3].[Cr] QRRWWGNBSQSBAM-UHFFFAOYSA-N 0.000 description 4
- 230000006399 behavior Effects 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000011233 carbonaceous binding agent Substances 0.000 description 1
- 239000000788 chromium alloy Substances 0.000 description 1
- 238000010410 dusting Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000005188 flotation Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C1/00—Making non-ferrous alloys
- C22C1/02—Making non-ferrous alloys by melting
- C22C1/03—Making non-ferrous alloys by melting using master alloys
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
Definitions
- the present invention relates to a process for producing chrome-aluminum balls for adding chromium to molten aluminum baths.
- each ball is formed of two heterogeneous components, namely on the one hand aluminum grains and on the other hand grains of chromium possibly alloyed, which exhibit different behaviors; in fact, the generally smaller particle size of the aluminum powder entering for a large part in the composition of the balls makes that part of this powder separates from the rest of the balls to float on the surface of the aluminum bath, to which this powder mixes poorly; in addition, the aluminum grains and the possibly alloyed chromium grains melt at different temperatures, so that their dissolution in the aluminum bath takes place under poor conditions.
- U.S. Patent No. 4,564,393 discloses another method is essentially distinguished from the method described by U.S. Patent No. 3,592,637 in that a flux is added to the mixture of aluminum powder and chromium powder, optionally alloyed , before compacting into balls; the balls made by this process exhibit heterogeneity similar to that of the balls manufactured according to the teachings of U.S. Patent No. 3,592,637, with the same effect, and furthermore have the disadvantage of being more expensive because of the addition of the flow.
- the object of the present invention is to remedy these drawbacks, by proposing a process making it possible to economically produce balls having a precise chromium and aluminum content, with a homogeneity conducive to dissolution under the best conditions when incorporated into a molten aluminum bath.
- the balls resulting from the compacting of the powder thus obtained have all or at least most of their aluminum content in the form of chromium-aluminum alloy grains, having a homogeneous content of these two components and consequently melting at temperatures identical, which we note that they are lower than those of aluminum or chromium considered separately, so that the dissolution of the balls takes place under particularly favorable conditions; the possible addition of finely divided aluminum only intervenes as an adjustment of the aluminum content, in proportions which can be reduced to less than 5% of the weight of crude powder and for example less than 2% or of the order of approximately 2% of the weight of raw powder, thanks to a careful production of the chromium-aluminum alloy, which makes the disadvantages inherent in the presence of aluminum in the form of metallic powder practically negligible, namely the heterogeneity of melting temperature and the risk of flotation of this powder.
- a binder which is advantageously a carbonaceous binder such as bakelite, which binder is added in sufficiently small proportions so as not to have any influence on the behavior of the balls when 'they are immersed in a bath of molten aluminum; naturally, the compaction process is chosen by the skilled person according to the absence of binder or the presence of binder, as well as the nature of the binder.
- the alloy thus produced is then finely ground into a crude powder having a particle size advantageously between approximately 0.250 mm and approximately 0.053 mm, and this crude powder or else the alloy itself is analyzed in order to determine the content of the crude powder and of the alloy by weight of chromium and by weight of aluminum.
- the content of the raw powder or of the alloy by weight of aluminum is less than the 25% sought, an aluminum contribution is made in finely divided form to adjust to the required 25% the aluminum content, and to the required 75% the chromium content; experience shows that, by a good mastery of the aluminothermic technique used to make the alloy of chromium and aluminum, the contribution of aluminum in the form of finely divided aluminum powder can be reduced to 2% about or less than 2%, by weight, of the weight of chromium-aluminum alloy powder; the finely divided aluminum thus optionally added to the raw powder advantageously has a particle size less than 420 ⁇ m, with a proportion of aluminum powder with a particle size less than 53 ⁇ m not exceeding 15% of the total weight of aluminum thus optionally added .
- This powder advantageously has a density of the order of 2.5 ⁇ 0.2.
- bakelite is added to this powder, at a rate of approximately 2 ° / 00 by weight of bakelite relative to the weight of the powder containing 25% chromium and 75% aluminum, then the compacting under a pressure and a temperature easily determinable by a person skilled in the art, capable of imparting to the balls obtained by this compacting a density advantageously of the order of 5.6 ⁇ 0.2 and of causing the setting of the bakelite; the balls are then ready for use.
- a binder is preferred insofar as it makes it possible to avoid dusting of the bou lets; experience has shown that the presence of a small quantity of aluminum in powder form, in the non-alloyed state, makes it possible to considerably reduce the quantity of binder required, and to make the presence of this binder without consequence on the aluminum bath; this quantity of aluminum in powder form, in the non-alloyed state, is for example of the order of 2%, by weight, of the weight of powder of chromium-aluminum alloy.
- the implementation of the method according to the invention is not limited to the production of balls containing 75% chromium and 25% aluminum, and this method can be applied with the same advantages for chromium contents. ranging from 70 to 80%, with the% aluminum complement.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacture Of Metal Powder And Suspensions Thereof (AREA)
- Powder Metallurgy (AREA)
- Manufacture And Refinement Of Metals (AREA)
Abstract
La présente invention concerne un procédé de réalisation de boulets chrome-aluminium pour l'ajout de chrome dans des bains d'aluminium en fusion. Pour obtenir des boulets contenant x% de chrome et y% d'aluminium, où x et y sont des teneurs en poids répondant aux relations suivantes : 70 <= x <= 80 20 <= y <= 30 x+y = 100 on réalise par fusion un alliage de chrome et d'aluminium contenant des teneurs en poids de chrome et d'aluminium approximant respectivement x par excès et y par défaut, puis on broie finement cet alliage en une poudre brute ; on analyse les teneurs en chrome et en aluminium de l'alliage ou de la poudre brute et, si besoin est, on apporte à la poudre brute un complément d'aluminium finement divisé pour obtenir une poudre contenant x% de chrome et y% d'aluminium, le complément d'aluminium finement divisé correspondant à moins de 10% du poids de la poudre brute ; on pratique ensuite un compactage. On obtient ainsi des boulets essentiellement formés de grains d'alliage présentant la même température de fusion et risquant peu de flotter à la surface du bain d'aluminium en fusion, ce qui favorise la dissolution des boulets dans ce dernier.The present invention relates to a process for producing chrome-aluminum balls for adding chromium to molten aluminum baths. To obtain balls containing x% of chromium and y% of aluminum, where x and y are contents by weight answering the following relations: 70 <= x <= 80 20 <= y <= 30 x + y = 100 on produced by fusion an alloy of chromium and aluminum containing contents by weight of chromium and aluminum approximating respectively x by excess and y by default, then this alloy is finely ground into a crude powder; the chromium and aluminum contents of the alloy or of the crude powder are analyzed and, if necessary, finely divided aluminum is added to the crude powder to obtain a powder containing x% chromium and y% d aluminum, the finely divided aluminum supplement corresponding to less than 10% of the weight of the raw powder; compaction is then carried out. Balls are thus obtained which are essentially formed of alloy grains having the same melting temperature and which are unlikely to float on the surface of the molten aluminum bath, which promotes the dissolution of the balls in the latter.
Description
La présente invention concerne un procédé de réalisation de boulets chrome-aluminium pour l'ajout de chrome dans des bains d'aluminium en fusion.The present invention relates to a process for producing chrome-aluminum balls for adding chromium to molten aluminum baths.
Plus précisément, elle concerne la réalisation de tels boulets, contenant x% de chrome et y% d'aluminium où x et y sont des teneurs en poids répondant aux relations suivantes :
70 ≦ x ≦ 80
20 ≦ y ≦ 30
x+y = 100,
par réalisation d'une poudre contenant x% de chrome et y% d'aluminium puis compactage de cette poudre en boulets.More specifically, it relates to the production of such balls, containing x% chromium and y% aluminum where x and y are weight contents corresponding to the following relationships:
70 ≦ x ≦ 80
20 ≦ y ≦ 30
x + y = 100,
by making a powder containing x% chromium and y% aluminum and then compacting this powder into balls.
Selon un procédé connu, décrit par le brevet américain No 3 592 637, on réalise des boulets destines à l'ajout de chrome dans des bains d'aluminium en fusion par compactage d'une poudre que l'on obtient en mélangeant une quantité de l'ordre de 10% à 90% d'un matériau finement divisé formé de chrome ou d'un alliage de chrome, et environ 10 à 90% d'aluminium finement divisé, dont la présence sous cette forme est présentée, dans ce brevet américain, comme indispensable pour assurer la dissolution ultérieure des boulets dans le bain d'aluminium en fusion.According to a known method, disclosed by U.S. Patent No. 3,592,637, is carried balls designed for the addition of chromium in the molten aluminum bath by compaction of a powder obtained by mixing an amount on the order of 10% to 90% of a finely divided material formed from chromium or a chromium alloy, and approximately 10 to 90% of finely divided aluminum, the presence of which in this form is presented, in this American patent, as essential to ensure the subsequent dissolution of the balls in the molten aluminum bath.
Or, il apparant que les boulets obtenus par ce procédé connu ne donnent pas entièrement satisfaction ; en effet, chaque boulet est formé de deux composants hétérogènes, à savoir d'une part des grains d'aluminium et d'autre part des grains de chrome éventuellement allié, lesquels présentent des comportements différents ; en effet, la granulométrie généralement plus faible de la poudre d'aluminium entrant pour une part importante dans la composition des boulets fait qu'une partie de cette poudre se sépare du reste des boulets pour venir flotter à la surface du bain d'aluminium, auquel cette poudre se mélange mal ; en outre, les grains d'aluminium et les grains de chrome éventuellement allié fondent à des températures différentes, si bien que leur dissolution dans le bain d'aluminium s'effectue dans de mauvaises conditions.However, it appears that the balls obtained by this known process are not entirely satisfactory; indeed, each ball is formed of two heterogeneous components, namely on the one hand aluminum grains and on the other hand grains of chromium possibly alloyed, which exhibit different behaviors; in fact, the generally smaller particle size of the aluminum powder entering for a large part in the composition of the balls makes that part of this powder separates from the rest of the balls to float on the surface of the aluminum bath, to which this powder mixes poorly; in addition, the aluminum grains and the possibly alloyed chromium grains melt at different temperatures, so that their dissolution in the aluminum bath takes place under poor conditions.
Le brevet américain No 4 564 393 décrit un autre procédé se distinguant essentiellement du procédé décrit par le brevet américain No 3 592 637 par le fait qu'un flux est ajouté au mélange de poudre d'aluminium et de poudre de chrome éventuellement allié , avant compactage en boulets ; les boulets réalisés par ce procédé présentent une hétérogénéité comparable à celle des boulets fabriqués selon les enseignements du brevet américain No 3 592 637, avec les mêmes conséquences, et présentent en outre l'inconvénient d'être plus coûteux en raison de l'addition du flux.U.S. Patent No. 4,564,393 discloses another method is essentially distinguished from the method described by U.S. Patent No. 3,592,637 in that a flux is added to the mixture of aluminum powder and chromium powder, optionally alloyed , before compacting into balls; the balls made by this process exhibit heterogeneity similar to that of the balls manufactured according to the teachings of U.S. Patent No. 3,592,637, with the same effect, and furthermore have the disadvantage of being more expensive because of the addition of the flow.
Le but de la présente invention est de remédier à ces inconvénients, en proposant un procédé permettant de réaliser économiquement des boulets présentant une teneur précise en chrome et en aluminium, avec une homogénéité propice à une dissolution dans les meilleures conditions lors de leur incorporation à un bain d'aluminium en fusion.The object of the present invention is to remedy these drawbacks, by proposing a process making it possible to economically produce balls having a precise chromium and aluminum content, with a homogeneity conducive to dissolution under the best conditions when incorporated into a molten aluminum bath.
A cet effet, la présente invention propose de réaliser la poudre contenant x% de chrome et y% d'aluminium, où x et y sont définis comme indiqués plus haut, par la succession des étapes consistant à :
- a) réaliser par fusion un alliage de Cr et Al contenant des teneurs en poids de Cr et d'Al approximant respectivement x par excès et y par défaut,
- b) broyer finement ledit alliage en une poudre brute et analyser les teneurs respectives dudit alliage ou de ladite poudre brute en poids de Cr et d'Al,
- c) si la teneur de l'alliage ou de la poudre brute en poids d'Al est inférieure à y, apporter à la poudre brute un complément d'Al finement divisé pour obtenir ladite poudre contenant x% de Cr et y% d'Al, ledit complément d'Al finement divisé correspondant à moins de 10% du poids de poudre brute.
- a) producing by fusion an alloy of Cr and Al containing contents by weight of Cr and Al approximating respectively x by excess and y by default,
- b) finely grinding said alloy into a crude powder and analyzing the respective contents of said alloy or of said crude powder by weight of Cr and Al,
- c) if the content of the alloy or of the crude powder by weight of Al is less than y, supply the crude powder with a finely divided complement of Al to obtain said powder containing x% of Cr and y% of Al, said finely divided Al complement corresponding to less than 10% of the weight of crude powder.
Les boulets résultant du compactage de la poudre ainsi obtenue présente la totalité ou au moins l'essentiel de leur teneur en aluminium sous forme de grains d'alliage chrome-aluminium, présentant une teneur homogène en ces deux composants et fondant par conséquent à des températures identiques, dont on remarque qu'elles sont inférieures à celles de l'aluminium ou du chrome considéré séparément, si bien que la dissolution des boulets s'effectue dans des conditions particulièrement favorables ; l'éventuel complément d'aluminium finement divisé n'intervient qu'à titre d'ajustement de la teneur en aluminium, dans des proportions qui peuvent être réduites à moins de 5% du poids de poudre brute et par exemple inférieures à 2% ou de l'ordre de 2% environ du poids de poudre brute, grâce à une réalisation soignée de l'alliage de chrome et d'aluminium, ce qui rend pratiquement négligeables les inconvénients inhérents à la présence d'aluminium sous forme de poudre métallique, à savoir l'hétérogénéité de température de fusion et le risque de flottation de cette poudre.The balls resulting from the compacting of the powder thus obtained have all or at least most of their aluminum content in the form of chromium-aluminum alloy grains, having a homogeneous content of these two components and consequently melting at temperatures identical, which we note that they are lower than those of aluminum or chromium considered separately, so that the dissolution of the balls takes place under particularly favorable conditions; the possible addition of finely divided aluminum only intervenes as an adjustment of the aluminum content, in proportions which can be reduced to less than 5% of the weight of crude powder and for example less than 2% or of the order of approximately 2% of the weight of raw powder, thanks to a careful production of the chromium-aluminum alloy, which makes the disadvantages inherent in the presence of aluminum in the form of metallic powder practically negligible, namely the heterogeneity of melting temperature and the risk of flotation of this powder.
Au contraire, l'éventuel complément de poudre d'aluminium contribue à la compacité des boulets, c'est- à-dire contribue à éviter une trop grande friabilité de ces derniers.On the contrary, the possible addition of aluminum powder contributes to the compactness of the balls, that is to say, helps to avoid too much friability of the latter.
A cet effet, on peut également ajouter à la poudre, avant compactage, un liant qui est avantageusement un liant carboné tel que la bakélite, lequel liant est ajouté dans des proportions suffisamment faibles pour ne pas avoir d'influence sur le comportement des boulets lorsqu'on les plonge dans un bain d'aluminium en fusion ; naturellement, le procédé de compactage est choisi par l'Homme du métier en fonction de l'absence de liant ou de la présence de liant, ainsi que de la nature du liant.For this purpose, it is also possible to add to the powder, before compacting, a binder which is advantageously a carbonaceous binder such as bakelite, which binder is added in sufficiently small proportions so as not to have any influence on the behavior of the balls when 'they are immersed in a bath of molten aluminum; naturally, the compaction process is chosen by the skilled person according to the absence of binder or the presence of binder, as well as the nature of the binder.
D'autres caractéristiques et avantages de l'invention ressortiront de la description ci-dessous, relative à un mode de mise en oeuvre non limitatif.Other characteristics and advantages of the invention will emerge from the description below, relating to a non-limiting mode of implementation.
Dans cet exemple, on désire réaliser des boulets contenant 75% de chrome et 25% d'aluminium et, à cet effet, on commence par réaliser par fusion, par exemple par aluminothermie, un alliage de chrome et d'aluminium présentant des teneurs en poids de chrome et d'aluminium approximant respectivement 75% par excès et 25% par défaut.In this example, it is desired to produce balls containing 75% of chromium and 25% of aluminum and, for this purpose, one begins by producing by fusion, for example by aluminothermy, an alloy of chromium and aluminum having contents in weight of chromium and aluminum approximating respectively 75% by excess and 25% by default.
L'alliage ainsi réalisé est ensuite broyé finement en une poudre brute présentant une granulométrie comprise avantageusement entre 0,250 mm environ et 0,053 mm environ, et cette poudre brute ou bien l'alliage lui-même est analysé afin de déterminer la teneur de la poudre brute et de l'alliage en poids de chrome et en poids d'aluminium.The alloy thus produced is then finely ground into a crude powder having a particle size advantageously between approximately 0.250 mm and approximately 0.053 mm, and this crude powder or else the alloy itself is analyzed in order to determine the content of the crude powder and of the alloy by weight of chromium and by weight of aluminum.
Si ces teneurs correspondent respectivement aux 75% et 25% recherchés, aucune addition de poudre d'aluminium n'est nécessaire.If these contents correspond respectively to the 75% and 25% sought, no addition of aluminum powder is necessary.
Si, par contre, la teneur de la poudre brute ou de l'alliage en poids d'aluminium est inférieure aux 25% recherché, on réalise un apport d'aluminium sous forme finement divisée pour ajuster aux 25% requis la teneur en aluminium, et aux 75% requis la teneur en chrome ; l'expérience montre que, par une bonne maîtrise de la technique d'aluminothermie utilisée pour réaliser l'alliage de chrome et d'aluminium, l'apport d'aluminium sous forme de poudre d'aluminium finement divisé peut être réduit à 2% environ ou à moins de 2%, en poids, du poids de poudre d'alliage chrome-aluminium ; l'aluminium finement divisé ainsi éventuellement ajouté à la poudre brute présente avantageusement une granulométrie inférieure à 420µm, avec une proportion de poudre d'aluminium d'une granulométrie inférieure à 53µm n'excédant pas 15% du poids total d'aluminium ainsi éventuellement ajouté.If, on the other hand, the content of the raw powder or of the alloy by weight of aluminum is less than the 25% sought, an aluminum contribution is made in finely divided form to adjust to the required 25% the aluminum content, and to the required 75% the chromium content; experience shows that, by a good mastery of the aluminothermic technique used to make the alloy of chromium and aluminum, the contribution of aluminum in the form of finely divided aluminum powder can be reduced to 2% about or less than 2%, by weight, of the weight of chromium-aluminum alloy powder; the finely divided aluminum thus optionally added to the raw powder advantageously has a particle size less than 420 μm, with a proportion of aluminum powder with a particle size less than 53 μm not exceeding 15% of the total weight of aluminum thus optionally added .
Dans l'un et l'autre cas, on obtient ainsi une poudre contenant aussi précisément que possible 25% de chrome et 75% d'aluminium.In both cases, a powder is thus obtained containing as precisely as possible 25% chromium and 75% aluminum.
Cette poudre présente avantageusement une densité de l'ordre de 2,5 ± 0,2.This powder advantageously has a density of the order of 2.5 ± 0.2.
Ensuite, de préférence, on ajoute à cette poudre de la bakélite, à raison d'environ 2°/00 en poids de bakélite par rapport au poids de la poudre contenant 25% de chrome et 75% d'aluminium, puis on pratique le compactage sous une pression et une température aisément déterminables par un Homme du métier, propres à communiquer aux boulets obtenus par ce compactage une densité avantageusement de l'ordre de 5,6 ± 0,2 et à provoquer la prise de la bakélite ; les boulets sont ensuite prêts à l'usage.Then, preferably, bakelite is added to this powder, at a rate of approximately 2 ° / 00 by weight of bakelite relative to the weight of the powder containing 25% chromium and 75% aluminum, then the compacting under a pressure and a temperature easily determinable by a person skilled in the art, capable of imparting to the balls obtained by this compacting a density advantageously of the order of 5.6 ± 0.2 and of causing the setting of the bakelite; the balls are then ready for use.
L'addition d'un liant est préférée dans la mesure où elle permet d'éviter un poudroiement des bou lets ; l'expérience a montré que la présence d'une faible quantité d'aluminium sous forme de poudre, à l'état non allié, permet de réduire considérablement la quantité de liant nécessaire, et de rendre la présence de ce liant sans conséquence sur le bain d'aluminium ; cette quantité d'aluminium sous forme de poudre, à l'état non allié, est par exemple de l'ordre de 2%, en poids, du poids de poudre d'alliage chrome-aluminium.The addition of a binder is preferred insofar as it makes it possible to avoid dusting of the bou lets; experience has shown that the presence of a small quantity of aluminum in powder form, in the non-alloyed state, makes it possible to considerably reduce the quantity of binder required, and to make the presence of this binder without consequence on the aluminum bath; this quantity of aluminum in powder form, in the non-alloyed state, is for example of the order of 2%, by weight, of the weight of powder of chromium-aluminum alloy.
En variante, on peut cependant également se dispenser de tout liant en pratiquant un compactage approprié.Alternatively, one can also dispense with any binder by practicing appropriate compaction.
Naturellement, la mise en oeuvre du procédé selon l'invention n'est pas limitée à la réalisation de boulets contenant 75% de chrome et 25% d'aluminium, et ce procédé peut s'appliquer avec les mêmes avantages pour des teneurs en chrome allant de 70 à 80%, avec le complément % en aluminium.Naturally, the implementation of the method according to the invention is not limited to the production of balls containing 75% chromium and 25% aluminum, and this method can be applied with the same advantages for chromium contents. ranging from 70 to 80%, with the% aluminum complement.
Dans chaque cas, on veille à éviter les inconvénients liés à la présence d'une trop grande quantité d'aluminium non allié sous forme de poudre en ajustant aussi précisément que possible les teneurs, en chrome et en aluminium, de l'alliage pour réduire aussi bas que possible en dessous de 10% le complément d'aluminium non allié ajouté sous forme de poudre à cet alliage ; de préférence, on respecte également dans chaque cas les granulométries et densités indiquées précédemment, actuellement considérées comme préférables bien que d'autres valeurs puissent également être choisies sans que l'on sorte pour autant du cadre de la présente invention.In each case, care is taken to avoid the drawbacks associated with the presence of too large a quantity of unalloyed aluminum in powder form by adjusting the chromium and aluminum contents of the alloy as precisely as possible to reduce as low as possible below 10% the complement of unalloyed aluminum added in powder form to this alloy; preferably, the grain sizes and densities indicated above, which are currently considered preferable, are also respected in each case, although other values can also be chosen without departing from the scope of the present invention.
Claims (12)
70≦ x ≦ 80
20 ≦ y ≦ 30
x+y = 100
pour l'ajout de Cr dans des bains d'aluminium en fusion, par réalisation d'une poudre contenant x% de Cr et y% d'Al puis compactage de cette poudre en boulets, caractérisé en ce que l'on réalise ladite poudre par la succession des etapes consistant à :
70 ≦ x ≦ 80
20 ≦ y ≦ 30
x + y = 100
for adding Cr to molten aluminum baths, by producing a powder containing x% Cr and y% Al and then compacting this powder into balls, characterized in that said powder is produced by the succession of stages consisting in:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT87402937T ATE64762T1 (en) | 1986-12-22 | 1987-12-21 | PROCESS FOR THE MANUFACTURE OF CHROMIUM ALUMINUM BALLS AS CHROMIUM ADDITIVES TO ALUMINUM MELT. |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8617981A FR2608478B1 (en) | 1986-12-22 | 1986-12-22 | PROCESS FOR PRODUCING CHROME-ALUMINUM BALLS FOR THE ADDITION OF CHROME IN MOLTEN ALUMINUM BATHS |
| FR8617981 | 1986-12-22 |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| EP0275774A2 true EP0275774A2 (en) | 1988-07-27 |
| EP0275774A3 EP0275774A3 (en) | 1988-08-03 |
| EP0275774B1 EP0275774B1 (en) | 1991-06-26 |
Family
ID=9342163
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP87402937A Expired - Lifetime EP0275774B1 (en) | 1986-12-22 | 1987-12-21 | Process for preparing chromium-aluminium agglomerates for adding chromium to a melt of aluminium |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US4820483A (en) |
| EP (1) | EP0275774B1 (en) |
| AT (1) | ATE64762T1 (en) |
| DE (1) | DE3771059D1 (en) |
| FR (1) | FR2608478B1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2299099A (en) * | 1995-03-18 | 1996-09-25 | Christopher Duncan Mayes | Process for producing grain refining master alloys. |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5316723A (en) * | 1992-07-23 | 1994-05-31 | Reading Alloys, Inc. | Master alloys for beta 21S titanium-based alloys |
| ATE286990T1 (en) * | 1999-04-15 | 2005-01-15 | Bostlan Sa | ADDITIVE FOR ADDING METALS TO ALUMINUM ALLOYS |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3592637A (en) * | 1968-02-26 | 1971-07-13 | Union Carbide Corp | Method for adding metal to molten metal baths |
| US4104059A (en) * | 1977-05-27 | 1978-08-01 | Reading Alloys, Inc. | Molybdenum-titanium-zirconium-aluminum master alloys |
| WO1984000050A1 (en) * | 1982-06-17 | 1984-01-05 | Pechiney Aluminium | Motor cylinder sleeves based on aluminum alloys and calibrated silicon grains and methods for obtaining them |
| EP0102892A1 (en) * | 1982-08-20 | 1984-03-14 | C. Delachaux | Process for manufacturing high purity metals and alloys |
| EP0229499A1 (en) * | 1985-12-16 | 1987-07-22 | Inco Alloys International, Inc. | Formation of intermetallic and intermetallic-type precursor alloys for subsequent mechanical alloying applications |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA1005220A (en) * | 1974-02-25 | 1977-02-15 | National Research Council Of Canada | Method for producing ball agglomerated particulate material |
| GB2112020B (en) * | 1981-12-23 | 1985-07-03 | London And Scandinavian Metall | Introducing one or more metals into a melt comprising aluminium |
| US4689199A (en) * | 1984-09-27 | 1987-08-25 | Aluminum Company Of America | Process for adding material to molten media |
-
1986
- 1986-12-22 FR FR8617981A patent/FR2608478B1/en not_active Expired
-
1987
- 1987-12-21 AT AT87402937T patent/ATE64762T1/en not_active IP Right Cessation
- 1987-12-21 EP EP87402937A patent/EP0275774B1/en not_active Expired - Lifetime
- 1987-12-21 DE DE8787402937T patent/DE3771059D1/en not_active Expired - Fee Related
- 1987-12-22 US US07/137,661 patent/US4820483A/en not_active Expired - Lifetime
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3592637A (en) * | 1968-02-26 | 1971-07-13 | Union Carbide Corp | Method for adding metal to molten metal baths |
| US4104059A (en) * | 1977-05-27 | 1978-08-01 | Reading Alloys, Inc. | Molybdenum-titanium-zirconium-aluminum master alloys |
| WO1984000050A1 (en) * | 1982-06-17 | 1984-01-05 | Pechiney Aluminium | Motor cylinder sleeves based on aluminum alloys and calibrated silicon grains and methods for obtaining them |
| EP0102892A1 (en) * | 1982-08-20 | 1984-03-14 | C. Delachaux | Process for manufacturing high purity metals and alloys |
| EP0229499A1 (en) * | 1985-12-16 | 1987-07-22 | Inco Alloys International, Inc. | Formation of intermetallic and intermetallic-type precursor alloys for subsequent mechanical alloying applications |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2299099A (en) * | 1995-03-18 | 1996-09-25 | Christopher Duncan Mayes | Process for producing grain refining master alloys. |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0275774B1 (en) | 1991-06-26 |
| US4820483A (en) | 1989-04-11 |
| FR2608478A1 (en) | 1988-06-24 |
| DE3771059D1 (en) | 1991-08-01 |
| EP0275774A3 (en) | 1988-08-03 |
| ATE64762T1 (en) | 1991-07-15 |
| FR2608478B1 (en) | 1989-06-02 |
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