EP0133144B1 - Process for manufacturing extruded bodies from high strength aluminium base alloy powder - Google Patents
Process for manufacturing extruded bodies from high strength aluminium base alloy powder Download PDFInfo
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- EP0133144B1 EP0133144B1 EP84420126A EP84420126A EP0133144B1 EP 0133144 B1 EP0133144 B1 EP 0133144B1 EP 84420126 A EP84420126 A EP 84420126A EP 84420126 A EP84420126 A EP 84420126A EP 0133144 B1 EP0133144 B1 EP 0133144B1
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- Prior art keywords
- powder
- jacket
- aluminium alloy
- hot
- extruded
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- 239000000843 powder Substances 0.000 title claims description 41
- 238000000034 method Methods 0.000 title claims description 32
- 229910045601 alloy Inorganic materials 0.000 title claims description 23
- 239000000956 alloy Substances 0.000 title claims description 23
- 229910052782 aluminium Inorganic materials 0.000 title description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 title description 3
- 238000004519 manufacturing process Methods 0.000 title description 2
- 239000004411 aluminium Substances 0.000 title 1
- 239000011265 semifinished product Substances 0.000 claims description 15
- 229910000838 Al alloy Inorganic materials 0.000 claims description 11
- 239000000047 product Substances 0.000 claims description 10
- 238000000889 atomisation Methods 0.000 claims description 8
- 239000007789 gas Substances 0.000 claims description 7
- 239000003570 air Substances 0.000 claims description 6
- 239000012080 ambient air Substances 0.000 claims description 5
- 229910052744 lithium Inorganic materials 0.000 claims description 5
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 4
- 230000007935 neutral effect Effects 0.000 claims description 4
- 239000001307 helium Substances 0.000 claims description 3
- 229910052734 helium Inorganic materials 0.000 claims description 3
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims description 3
- 238000011068 loading method Methods 0.000 claims description 3
- 229910019086 Mg-Cu Inorganic materials 0.000 claims description 2
- 238000011282 treatment Methods 0.000 claims description 2
- 235000012438 extruded product Nutrition 0.000 claims 2
- 238000001125 extrusion Methods 0.000 claims 2
- 230000032683 aging Effects 0.000 claims 1
- 238000001033 granulometry Methods 0.000 claims 1
- 238000009987 spinning Methods 0.000 description 17
- 238000007906 compression Methods 0.000 description 14
- 230000006835 compression Effects 0.000 description 14
- 238000007872 degassing Methods 0.000 description 8
- 238000010438 heat treatment Methods 0.000 description 5
- IOUVKUPGCMBWBT-QNDFHXLGSA-N phlorizin Chemical compound O[C@@H]1[C@@H](O)[C@H](O)[C@@H](CO)O[C@H]1OC1=CC(O)=CC(O)=C1C(=O)CCC1=CC=C(O)C=C1 IOUVKUPGCMBWBT-QNDFHXLGSA-N 0.000 description 5
- 238000007747 plating Methods 0.000 description 5
- 238000005245 sintering Methods 0.000 description 5
- 230000008901 benefit Effects 0.000 description 3
- 239000002131 composite material Substances 0.000 description 3
- 239000001989 lithium alloy Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 229910000733 Li alloy Inorganic materials 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000005266 casting Methods 0.000 description 2
- 238000000280 densification Methods 0.000 description 2
- 230000001627 detrimental effect Effects 0.000 description 2
- 238000010036 direct spinning Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 238000003754 machining Methods 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 238000004663 powder metallurgy Methods 0.000 description 2
- 206010001488 Aggression Diseases 0.000 description 1
- 229910001148 Al-Li alloy Inorganic materials 0.000 description 1
- 229910000636 Ce alloy Inorganic materials 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 1
- JFBZPFYRPYOZCQ-UHFFFAOYSA-N [Li].[Al] Chemical compound [Li].[Al] JFBZPFYRPYOZCQ-UHFFFAOYSA-N 0.000 description 1
- 230000016571 aggressive behavior Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 230000001050 lubricating effect Effects 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000009702 powder compression Methods 0.000 description 1
- 230000000135 prohibitive effect Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000005496 tempering Methods 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Images
Classifications
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- 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
- C22C1/04—Making non-ferrous alloys by powder metallurgy
- C22C1/0408—Light metal alloys
- C22C1/0416—Aluminium-based 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
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/12—Both compacting and sintering
- B22F3/1208—Containers or coating used therefor
- B22F3/1216—Container composition
-
- 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
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/20—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces by extruding
Definitions
- the present invention relates to the production from high strength aluminum alloy powder of spun semi-finished products intended in particular for applications in the aeronautical industry.
- obtaining extruded semi-finished products may require, in an initial phase, either casting processes or powder compression processes.
- the choice between one or the other of these methods is made mainly according to the composition of the alloy used and the mechanical characteristics sought for the semi-finished product.
- the problem is to spin aluminum alloys in order to obtain semi-finished products intended more particularly for aeronautics and for which we seek both a relatively high breaking strength and generally greater than 500 MPa, and a suitable elongation at least equal to 5%.
- Such characteristics can be achieved by using either alloys which, according to the standards of the Aluminum Association, belong to the 7000 series and in particular the alloys 7090 and 7091, or more recently alloys of the lithium family, such as those which contain in particular 2 to 3% of lithium as well as other elements of addition such as copper, magnesium, zinc, zirconium, etc ...
- the powder obtained then has a particular morphology of spherical grains. These grains have the disadvantage of being poorly suited to compression and give rise to the formation of pieces of poor mechanical quality which tend to crumble.
- the compression ratio of the powder could be increased to avoid this annoyance, but this would therefore reduce the possibilities of subsequent degassing of the hot piece and thus harm the quality of the final product.
- this cold compression rate it is necessary to limit this cold compression rate so that before and during the sheathing, and in any case until they have been densified to 100%, these pieces have the possibility of reacting with the surrounding medium and in particular of capturing the humidity of the air, which causes besides an oxidation of the alloy, the formation of hydrogen within the billet. This hydrogen will cause the presence, in the semi-finished products resulting from the spinning of such plots, of porosities very detrimental to the desired high resistance.
- This process is characterized in that a powder is loaded either with an alloy of the 7000 series (alloy AI-Zn-Mg-Cu) or an alloy AI-Li, in a sheath of aluminum alloy of the series 5000, degas the powder hot under a pressure lower than atmospheric pressure, seals the sheath, spins the assembly in reverse while hot and heat treatment with ambient air.
- the alloy powder used is obtained by atomization in a neutral gas, preferably helium, and optionally by atomization in air in the case of alloys of the 7000 series, which are preferably alloys 7090 and 7091.
- This powder preferably has a particle size of less than 400 ⁇ m so as to obtain a suitable semi-finished product. It is loaded directly into the sheath at the outlet of the bulk atomizer without prior compression so that the cold compression phase provided for in the prior process is thus avoided.
- This has the advantage, while simplifying the process, of eliminating the problems inherent in pollution of the powder during this operation and of facilitating subsequent degassing.
- the powder can be cold pre-compressed before loading it into the sheath.
- the sheath used is made of aluminum alloy which lends itself well to deformation during the spinning operation, and preferably of A-G3 or A-G5. It has the shape of a closed cylindrical box. equipped on one of its bottoms with an appendix intended for filling and subsequent degassing. This sheath has a thickness of the order of a few millimeters which varies according to its diameter.
- the content of the sheath is connected to a gas pumping device via the appendix and under its action, a pressure is established and maintained below atmospheric pressure and in any case less than 0.13 Pa while bringing the sheath and its contents to a temperature between 350 and 550 ° C.
- the sheath is then sealed in a leaktight manner by an appropriate means, and subjected directly to a reverse spinning operation at a temperature between 350 and 500 ° C.
- the step of the prior art consisting of hot compressing and sintering the powder in a matrix before machining the sheath and spinning is omitted.
- the semi-finished product is compact and has a regular continuous plating in intimate contact with the underlying powder. But such a result can only be obtained by reverse spinning.
- the metal is pushed by means of a pestle along the press container, through a fixed die which determines the profile of the semi-finished product.
- the die In reverse spinning, the die is fixed on the pestle and the metal spins in a direction opposite to that of the advance of the pestle.
- the “lubricating action of the sheath eliminates any friction of the powder with the die, so that the spinning speeds usually used in the prior art can be significantly increased and speeds higher than those obtained during spinning products cast in hard alloys without risk of decohesion on the surface of the powder grains insufficiently sintered as was the case with the products obtained in the prior art by spinning after hot compression.
- Such a plated composite semi-finished product then lends itself very well to heat treatment operations, dissolving at 530 ° C. generally carried out on lithium alloys and tempering for 6 to 10 hours between 150 and 200 ° C. in ovens. conventional air without the need to take any special precautions since the waterproof sheath exerts a protective role vis-à-vis the environment.
- the present invention finds its application in obtaining semi-finished products having high mechanical strength, suitable elongation and good environmental resistance, characteristics which make them particularly suitable for applications in the aeronautical industry.
Description
La présente invention est relative à l'obtention à partir de poudre d'alliage d'aluminium à haute résistance de demi-produits filés destinés notamment à des applications dans l'industrie aéronautique.The present invention relates to the production from high strength aluminum alloy powder of spun semi-finished products intended in particular for applications in the aeronautical industry.
Dans le domaine de l'aluminium, l'obtention de demi-produits filés peut faire appel dans une phase initiale, soit à des procédés de coulée, soit à des procédés de compression de poudres. Le choix entre l'un ou l'autre de ces procédés est fait principalement en fonction de la composition de l'alliage mis en oeuvre et des caractéristiques mécaniques recherchées pour le demi-produit.In the aluminum sector, obtaining extruded semi-finished products may require, in an initial phase, either casting processes or powder compression processes. The choice between one or the other of these methods is made mainly according to the composition of the alloy used and the mechanical characteristics sought for the semi-finished product.
Dans la présente invention, le problème est de filer des alliages d'aluminium en vue d'obtenir des demi-produits destinés plus particulièrement à l'aéronautique et pour lesquels on recherche à la fois une résistance à la rupture relativement élevée et généralement supérieure à 500 MPa, et un allongement convenable au moins égal à 5 %.In the present invention, the problem is to spin aluminum alloys in order to obtain semi-finished products intended more particularly for aeronautics and for which we seek both a relatively high breaking strength and generally greater than 500 MPa, and a suitable elongation at least equal to 5%.
De telles caractéristiques peuvent être réalisées en mettant en oeuvre, soit des alliages qui, suivant les normes de l'Aluminium Association, appartiennent à la série des 7000 et notamment les alliages 7090 et 7091, soit plus récemment des alliages de la famille du lithium, tels que ceux qui contiennent notamment 2 à 3 % de lithium ainsi que d'autres éléments d'addition comme le cuivre, le magnésium, le zinc, le zirconium, etc...Such characteristics can be achieved by using either alloys which, according to the standards of the Aluminum Association, belong to the 7000 series and in particular the alloys 7090 and 7091, or more recently alloys of the lithium family, such as those which contain in particular 2 to 3% of lithium as well as other elements of addition such as copper, magnesium, zinc, zirconium, etc ...
Toutefois, les procédés classiques évoqués ci-dessus s'adaptent mal à ces alliages.However, the conventional methods mentioned above are ill-suited to these alloys.
En effet, si l'on opère par coulée, on obtient généralement une forte ségrégation du produit coulé qui présente alors une grande aptitude à la criquabilité, d'où un taux de rebut prohibitif des pièces ainsi réalisées. Quant aux demi-produits filés qui en résultent, leur structure à gros grains et à phases grossières les rendent particulièrement fragiles. Autant d'inconvénients qui rendent ce procédé inadapté au but recherché.Indeed, if one operates by casting, one generally obtains a strong segregation of the cast product which then has a great ability to be crackable, hence a prohibitive reject rate of the parts thus produced. As for the resulting semi-finished products, their coarse grain structure and coarse phases make them particularly fragile. So many drawbacks that make this process unsuitable for the intended purpose.
Si l'on recourt aux procédés de la métallurgie des poudres, on se heurte, notamment avec les alliages au lithium, car cet élément a une très grande réactivité chimique, à un problème de pollution par l'environnement.If we use the powder metallurgy processes, we come up against, especially with lithium alloys, because this element has a very high chemical reactivity, to a problem of pollution by the environment.
Certes, on peut pallier cette difficulté en protégeant momentanément la poudre du milieu extérieur par une gaine par exemple, jusqu'à ce qu'elle ait été densifiée par compression et frittage. Ce moyen a été appliqué aux alliages AI-Fe-Ce dans le brevet US 4 379 719 qui décrit un procédé comprenant les étapes suivantes :
- - pulvérisation de l'alliage par atomisation,
- - compression de la poudre sous forme d'un lopin,
- - mise sous gaine du lopin,
- - dégazage à chaud du lopin, sous pression réduite et fermeture de la gaine,
- - compression de l'ensemble à chaud dans une matrice et frittage de la poudre,
- - usinage de la gaine pour la séparer du lopin,
- - filage à chaud du lopin fritté,
- - application de traitements thermiques, de mise en solution éventuellement et de revenu nécessaire pour atteindre les caractéristiques requises.
- - atomization of the alloy,
- - compression of the powder in the form of a piece,
- - plating the plot,
- - hot degassing of the plot, under reduced pressure and closing of the sheath,
- - compression of the hot assembly in a matrix and sintering of the powder,
- - machining of the sheath to separate it from the piece,
- - hot spinning of the sintered piece,
- - application of heat treatments, optionally dissolving and income necessary to achieve the required characteristics.
Mais un tel procédé, outre le fait qu'il comporte une gamme d'opérations nombreuses et relativement complexes, présente également d'autres inconvénients. C'est ainsi que lorsqu'il s'agit de mettre en oeuvre des poudres très sensibles à l'environnement, on ne peut les fabriquer de façon classique par atomisation dans l'air car elles s'oxyderaient et conduiraient à des produits aux caractéristiques mécaniques inadaptées, Il faut donc recourir à des atmosphères de gaz neutre tel que l'hélium de préférence.However, such a method, apart from the fact that it includes a number of relatively complex operations, also has other drawbacks. Thus, when it comes to using powders which are very sensitive to the environment, they cannot be manufactured in the conventional way by atomization in air because they would oxidize and lead to products with characteristics. unsuitable mechanical properties, therefore use neutral gas atmospheres such as helium preferably.
Dans ces conditions d'atomisation, la poudre obtenue présente alors une morphologie particulière de grains sphériques. Ces grains ont le désavantage de mal se prêter à la compression et donnent lieu à la formation de lopins de mauvaise qualité mécanique qui tendent à s'effriter.Under these atomization conditions, the powder obtained then has a particular morphology of spherical grains. These grains have the disadvantage of being poorly suited to compression and give rise to the formation of pieces of poor mechanical quality which tend to crumble.
Certes, on pourrait augmenter le taux de compression de la poudre pour éviter cet ennui, mais on réduirait de ce fait les possibilités de dégazage ultérieur du lopin à chaud et on nuirait ainsi à la qualité du produit final. C'est pourquoi, on est obligé de limiter ce taux de compression à froid de sorte qu'avant et au cours de la mise sous gaine, et en tout cas jusqu'à ce qu'ils aient été densifiés à 100 %, ces lopins ont la possibilité de réagir avec le milieu environnant et de capter notamment l'humidité de l'air, ce qui provoque outre une oxydation de l'alliage, la formation d'hydrogène au sein du lopin. Cet hydrogène va entraîner la présence, dans les demi-produits résultant du filage de tels lopins, de porosités très préjudiciables à la haute résistance souhaitée.Admittedly, the compression ratio of the powder could be increased to avoid this annoyance, but this would therefore reduce the possibilities of subsequent degassing of the hot piece and thus harm the quality of the final product. This is why, it is necessary to limit this cold compression rate so that before and during the sheathing, and in any case until they have been densified to 100%, these pieces have the possibility of reacting with the surrounding medium and in particular of capturing the humidity of the air, which causes besides an oxidation of the alloy, the formation of hydrogen within the billet. This hydrogen will cause the presence, in the semi-finished products resulting from the spinning of such plots, of porosities very detrimental to the desired high resistance.
De plus, la présence de ce gaz et d'autres produits de la réaction avec l'environnement va limiter le taux de frittage et empêcher d'atteindre une densification finale convenable lors de l'opération de compression à chaud. C'est pourquoi, il est impératif de procéder à un dégazage poussé du lopin.In addition, the presence of this gas and other products of the reaction with the environment will limit the sintering rate and prevent reaching a suitable final densification during the hot compression operation. That is why it is imperative to proceed with a thorough degassing of the plot.
Néanmoins, dans les conditions du procédé évoqué ci-dessus, et en prenant toutes les précautions pour réaliser un bon dégazage, on constate dans la plupart des cas qu'après compression à chaud et frittage du lopin au sein de la gaine, puis élimination de la gaine, le produit obtenu se file mal et conduit à des demi-produits criqués sur lesquels apparaissent des décohésions locales.However, under the conditions of the process mentioned above, and taking all the precautions to achieve good degassing, it is found in most cases that after hot compression and sintering of the slug within the sheath, then elimination of the sheath, the product obtained does not file well and leads to cracked semi-products on which local decohesions appear.
Dans une certaine mesure, on a pu parer à ces défauts en jouant sur la température du filage, la nature de l'outillage ou même en diminuant la vitesse de filage mais c'est alors au détriment de l'économie du procédé.To a certain extent, these defects could be countered by playing on the spinning temperature, the nature of the tooling or even by reducing the spinning speed, but this is to the detriment of the economy of the process.
En outre, dans le cas des alliages aluminium- lithium, il faut prendre des précautions lors des traitements thermiques destinés à améliorer leurs caractéristiques mécaniques, en raison de leur sensibilité à l'environnement. En particulier, on ne peut pas procéder à ces traitements dans des fours à l'air ambiant.In addition, in the case of aluminum-lithium alloys, care must be taken during heat treatments intended to improve their mechanical characteristics, because of their sensitivity to the environment. In particular, we cannot carry out these treatments in ovens with ambient air.
Au vu des difficultés inhérentes à ce procédé de l'art antérieur, mais voulant néanmoins bénéficier des avantages de la métallurgie des poudres, la demanderesse a cherché à le modifier afin de mieux l'adapter au problème posé. En particulier, elle a voulu, tout en simplifiant le procédé, faciliter le dégazage à chaud de la poudre, améliorer les conditions de filage pour éviter les criques et les décohésions et permettre les traitements thermiques sans précaution particulière.In view of the difficulties inherent in this process of the prior art, but nevertheless wishing to benefit from the advantages of powder metallurgy, the applicant sought to modify it in order to better adapt it to the problem posed. In particular, it wanted, while simplifying the process, to facilitate the hot degassing of the powder, to improve the spinning conditions to avoid cracks and decohesions and to allow heat treatments without special precautions.
Elle est arrivée ainsi à obtenir des demi-produits filés sous forme de composites plaqués dans lesquels l'âme en alliage à haute résistance, initialement pulvérulente, a été protégée constamment au cours de sa mise en forme de l'action polluante de l'environnement par une gaine étanche, ce qui confère une structure saine dépourvue de toute porosité et de haute résistance, et où ladite âme se trouve en contact intime avec une gaine qui épouse fidèlement la forme de la filière, ce qui donne au composite une structure compacte et de géométrie régulière.It thus obtained semi-finished products in the form of plated composites in which the core of high resistance alloy, initially powdery, was constantly protected during its shaping from the polluting action of the environment. by a tight sheath, which gives a healthy structure devoid of any porosity and high resistance, and where said core is in intimate contact with a sheath which faithfully follows the shape of the die, which gives the composite a compact structure and of regular geometry.
Ce procédé est caractérisé en ce que l'on charge une poudre soit d'un alliage de la série 7000 (alliage AI-Zn-Mg-Cu) soit un alliage AI-Li, dans une gaine en alliage d'aluminium de la série 5000, dégaze la poudre à chaud sous une pression inférieure à la pression atmosphérique, scelle la gaine, file l'ensemble en inverse à chaud et traite thermiquement à l'air ambiant.This process is characterized in that a powder is loaded either with an alloy of the 7000 series (alloy AI-Zn-Mg-Cu) or an alloy AI-Li, in a sheath of aluminum alloy of the series 5000, degas the powder hot under a pressure lower than atmospheric pressure, seals the sheath, spins the assembly in reverse while hot and heat treatment with ambient air.
La poudre d'alliage utilisée est obtenue par atomisation dans un gaz neutre, de préférence l'hélium, et éventuellement par atomisation dans l'air dans le cas des alliages de la série 7000, qui sont de préférence des alliages 7090 et 7091.The alloy powder used is obtained by atomization in a neutral gas, preferably helium, and optionally by atomization in air in the case of alloys of the 7000 series, which are preferably alloys 7090 and 7091.
Cette poudre a de préférence une granulométrie inférieure à 400 ¡.Lm de façon à obtenir un demi-produit convenable. Elle est chargée directement dans la gaine à la sortie de l'atomiseur en vrac sans compression préalable de sorte qu'on évite ainsi la phase de compression à froid prévue dans le procédé antérieur. Ceci a pour avantage, tout en simplifiant le procédé, de supprimer les problèmes inhérents à la pollution de la poudre lors de cette opération et de faciliter le dégazage ultérieur. Toutefois, pour certaines poudres de densité faible, obtenues à partir des alliages de la série 7000 atomisés dans l'air, on peut procéder à une précompression à froid de la poudre avant de la charger dans la gaine.This powder preferably has a particle size of less than 400 μm so as to obtain a suitable semi-finished product. It is loaded directly into the sheath at the outlet of the bulk atomizer without prior compression so that the cold compression phase provided for in the prior process is thus avoided. This has the advantage, while simplifying the process, of eliminating the problems inherent in pollution of the powder during this operation and of facilitating subsequent degassing. However, for certain powders of low density, obtained from alloys of the 7000 series atomized in air, the powder can be cold pre-compressed before loading it into the sheath.
La gaine utilisée est en alliage d'aluminium se prêtant bien à la déformation lors de l'opération de filage, et de préférence en A-G3 ou en A-G5. Elle a la forme d'une boîte cylindrique fermée. équipée sur l'un de ses fonds d'un appendice destiné au remplissage et au dégazage ultérieur. Cette gaine a une épaisseur de l'ordre de quelques millimètres qui varie suivant son diamètre.The sheath used is made of aluminum alloy which lends itself well to deformation during the spinning operation, and preferably of A-G3 or A-G5. It has the shape of a closed cylindrical box. equipped on one of its bottoms with an appendix intended for filling and subsequent degassing. This sheath has a thickness of the order of a few millimeters which varies according to its diameter.
Après chargement, le contenu de la gaine est relié à un dispositif de pompage de gaz par l'intermédiaire de l'appendice et sous son action, on établit et maintient une pression inférieure à la pression atmosphérique et en tout cas inférieure à 0,13 Pa tout en portant la gaine et son contenu à une température comprise entre 350 et 550 °C.After loading, the content of the sheath is connected to a gas pumping device via the appendix and under its action, a pressure is established and maintained below atmospheric pressure and in any case less than 0.13 Pa while bringing the sheath and its contents to a temperature between 350 and 550 ° C.
Dans ces conditions, le dégazage de l'alliage à haute résistance s'effectue parfaitement sans être entravé par les freinages qui résultaient dans le procédé de l'art antérieur du passage du gaz entre des grains de poudre serrés les uns contre les autres du fait de la compression initiale à froid.Under these conditions, the degassing of the high-strength alloy is carried out perfectly without being hampered by the braking which resulted in the process of the prior art from the passage of gas between grains of powder pressed against each other because of the initial cold compression.
La gaine est alors scellée de façon étanche par un moyen adéquat, et soumise directement à une opération de filage en inverse à une température comprise entre 350 et 500 °C.The sheath is then sealed in a leaktight manner by an appropriate means, and subjected directly to a reverse spinning operation at a temperature between 350 and 500 ° C.
Ainsi, on supprime l'étape de l'art antérieur consistant à comprimer à chaud et à fritter la poudre dans une matrice avant usinage de la gaine et filage.Thus, the step of the prior art consisting of hot compressing and sintering the powder in a matrix before machining the sheath and spinning is omitted.
On constate alors de façon surprenante que le demi-produit obtenu est compact et présente un placage régulier continu en contact intime avec la poudre sous-jacente. Mais un tel résultat ne peut être obtenu que par filage en inverse.It is then surprisingly found that the semi-finished product is compact and has a regular continuous plating in intimate contact with the underlying powder. But such a result can only be obtained by reverse spinning.
On sait, en effet, qu'il existe deux types principaux de filage : le filage direct et le filage inverse.We know, in fact, that there are two main types of spinning: direct spinning and reverse spinning.
- Dans le filage direct, le métal est poussé au moyen d'un pilon le long du conteneur de la presse, au travers d'une filière fixe qui détermine le profil du demi-produit.- In direct spinning, the metal is pushed by means of a pestle along the press container, through a fixed die which determines the profile of the semi-finished product.
Si on applique ce type de filage au lopin comprimé à chaud de l'art antérieur, il se produit un frottement important du métal sur la paroi du conteneur, ce qui entraîne l'apparition de criques et de décohésions locales dont on a parlé plus haut. Par contre, si on file l'ensemble gaine- conteneur suivant l'invention, la gaine sert de lubrifiant et diminue les frottements du produit avec le conteneur. Toutefois, cette gaine se déchire et pénètre à l'intérieur de la poudre de sorte que le demi-produit filé obtenu présente un placage discontinu avec des inclusions de gaine dans l'âme ce qui supprime toute protection ultérieure contre l'environnement et empêche l'obtention d'une haute résistance.If this type of spinning is applied to the hot compressed piece of the prior art, there is a significant friction of the metal on the wall of the container, which leads to the appearance of cracks and local decohesions which have been mentioned above. . On the other hand, if the sheath-container assembly according to the invention is spun, the sheath serves as a lubricant and reduces the friction of the product with the container. However, this sheath tears and penetrates inside the powder so that the spun semi-finished product obtained has a discontinuous plating with sheath inclusions in the core which eliminates any subsequent protection against the environment and prevents the high resistance.
- Dans le filage inverse, la filière est fixée sur le pilon et le métal file dans un sens opposé à celui de l'avance du pilon.- In reverse spinning, the die is fixed on the pestle and the metal spins in a direction opposite to that of the advance of the pestle.
Quand on applique ce type de filage à la poudre gainée, on constate que la densification de la poudre s'effectue correctement, que la gaine ne subit aucune déformation préjudiciable à la bonne étanchéité de la poudre comprimée sous-jacente, c'est-à-dire qu'elle ne se déchire pas, ni ne pénètre à l'intérieur de la poudre compactée mais forme un placage régulier et en contact intime avec toute la périphérie de l'alliage à haute résistance de sorte qu'il en résulte un demi-produit de rectitude convenable épousant parfaitement le profil de la filière utilisée et particulièrement insensible aux agressions de l'environnement. De plus, l'action « lubrifiante de la gaine supprime tout frottement de la poudre avec la filière, de sorte que l'on peut augmenter sensiblement les vitesses de filage habituellement utilisées dans l'art antérieur et atteindre des vitesses supérieures à celles obtenues lors du filage de produits coulés en alliages durs sans risque de décohésion en surface des grains de poudre insuffisamment frittés comme c'était le cas avec les produits obtenus dans l'art antérieur par filage après compression à chaud.When this type of spinning is applied to the sheathed powder, it can be seen that the densification of the powder is carried out correctly, that the sheath does not undergo any deformation detrimental to the good sealing of the underlying compressed powder, that is to say -to say that it does not tear, nor does it penetrate inside the compacted powder but forms a regular plating and in intimate contact with the entire periphery of the high-strength alloy so that it results in a half -product of suitable straightness perfectly matching the profile of the sector used and particularly insensitive to environmental aggressions. In addition, the “lubricating action of the sheath eliminates any friction of the powder with the die, so that the spinning speeds usually used in the prior art can be significantly increased and speeds higher than those obtained during spinning products cast in hard alloys without risk of decohesion on the surface of the powder grains insufficiently sintered as was the case with the products obtained in the prior art by spinning after hot compression.
Un tel demi-produit composite plaqué se prête alors très bien aux opérations de traitement thermique, de mise en solution à 530 °C pratiquées généralement sur les alliages au lithium et de revenu pendant 6 à 10 heures entre 150 et 200 °C dans des fours à l'air classiques sans qu'il soit nécessaire de prendre des précautions particulières puisque la gaine étanche exerce un rôle protecteur vis-à-vis de l'environnement.Such a plated composite semi-finished product then lends itself very well to heat treatment operations, dissolving at 530 ° C. generally carried out on lithium alloys and tempering for 6 to 10 hours between 150 and 200 ° C. in ovens. conventional air without the need to take any special precautions since the waterproof sheath exerts a protective role vis-à-vis the environment.
Les dessins qui accompagnent la présente demande sont relatifs à des méplats de 50 x 22 mm, filés à partir de poudres d'alliages AI-Li-Cu-Mg-Zr et d'une gaine en A-G3 suivant le procédé de l'invention. Ils montrent sur la figure 1 une coupe transversale et sur la figure 2 une coupe longitudinale du méplat.The drawings which accompany the present application relate to flats of 50 x 22 mm, spun from powders of alloys AI-Li-Cu-Mg-Zr and a sheath in A-G3 according to the process of invention. They show in Figure 1 a cross section and in Figure 2 a longitudinal section of the flat.
Sur la figure 1, on peut constater que la gaine (1) est disposée régulièrement tout autour de la partie compactée (2) et ne présente aucune séparation locale. De même, sur la figure 2, on peut également noter, outre la régularité du placage (3) autour de l'âme (4) une parfaite rectitude du profilé.In Figure 1, we can see that the sheath (1) is regularly arranged all around the compacted part (2) and has no local separation. Similarly, in Figure 2, we can also note, in addition to the regularity of the plating (3) around the core (4) a perfect straightness of the profile.
La présente invention trouve son application dans l'obtention de demi-produits ayant une grande résistance mécanique, un allongement convenable et une bonne tenue à l'environnement, caractéristiques qui les rendent particulièrement aptes à des applications dans l'industrie aéronautique.The present invention finds its application in obtaining semi-finished products having high mechanical strength, suitable elongation and good environmental resistance, characteristics which make them particularly suitable for applications in the aeronautical industry.
Claims (16)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8312381A FR2549493B1 (en) | 1983-07-21 | 1983-07-21 | PROCESS FOR OBTAINING HIGH STRENGTH ALUMINUM ALLOY POWDER FROM SPINED SEMI-PRODUCTS |
| FR8312381 | 1983-07-21 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0133144A1 EP0133144A1 (en) | 1985-02-13 |
| EP0133144B1 true EP0133144B1 (en) | 1986-11-12 |
Family
ID=9291139
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP84420126A Expired EP0133144B1 (en) | 1983-07-21 | 1984-07-18 | Process for manufacturing extruded bodies from high strength aluminium base alloy powder |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US4575450A (en) |
| EP (1) | EP0133144B1 (en) |
| DE (1) | DE3461256D1 (en) |
| FR (1) | FR2549493B1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6749926B1 (en) | 1999-07-23 | 2004-06-15 | Nippon Sheet Glass Company, Limited | Curved glass sheet for vehicle window |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3481322D1 (en) * | 1983-12-02 | 1990-03-15 | Sumitomo Electric Industries | ALUMINUM ALLOYS AND METHOD FOR THEIR PRODUCTION. |
| CH675089A5 (en) * | 1988-02-08 | 1990-08-31 | Asea Brown Boveri | |
| US5561829A (en) * | 1993-07-22 | 1996-10-01 | Aluminum Company Of America | Method of producing structural metal matrix composite products from a blend of powders |
| JP4373612B2 (en) | 1998-12-03 | 2009-11-25 | 日本板硝子株式会社 | Method and apparatus for manufacturing bent glass sheet |
| US7625520B2 (en) * | 2003-11-18 | 2009-12-01 | Dwa Technologies, Inc. | Manufacturing method for high yield rate of metal matrix composite sheet production |
| JP5059512B2 (en) * | 2007-02-28 | 2012-10-24 | 株式会社神戸製鋼所 | High strength, high ductility Al alloy and method for producing the same |
| JP5462957B1 (en) * | 2012-06-25 | 2014-04-02 | 株式会社栗本鐵工所 | Long light metal billet and manufacturing method thereof |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1155274A (en) * | 1955-08-18 | 1958-04-24 | Ver Leichtmetallwerke Gmbh | Method of applying a surface metal layer to sintered aluminum parts |
| GB879590A (en) * | 1959-02-27 | 1961-10-11 | Chesterfield Tube Company Ltd | Improvements relating to the forming of sintered articles |
| US3664889A (en) * | 1969-05-26 | 1972-05-23 | Lockheed Aircraft Corp | TERNARY, QUATERNARY AND MORE COMPLEX ALLOYS OF Be-Al |
| US3664008A (en) * | 1969-06-12 | 1972-05-23 | Federal Mogul Corp | Method of producing elongated highly densified powdered metal articles |
| US3954458A (en) * | 1973-11-12 | 1976-05-04 | Kaiser Aluminum & Chemical Corporation | Degassing powder metallurgical products |
| CH599348A5 (en) * | 1975-10-20 | 1978-05-31 | Bbc Brown Boveri & Cie | |
| FR2456783A1 (en) * | 1979-05-16 | 1980-12-12 | Cegedur | COMPOSITE HOLLOW BODY AND MANUFACTURING METHOD |
| US4460541A (en) * | 1980-01-16 | 1984-07-17 | Reynolds Metals Company | Aluminum powder metallurgy |
| DE3167605D1 (en) * | 1980-07-31 | 1985-01-17 | Mpd Technology | Dispersion-strengthened aluminium alloys |
| US4464199A (en) * | 1981-11-20 | 1984-08-07 | Aluminum Company Of America | Aluminum powder alloy product for high temperature application |
| US4379719A (en) * | 1981-11-20 | 1983-04-12 | Aluminum Company Of America | Aluminum powder alloy product for high temperature application |
| CA1230761A (en) * | 1982-07-12 | 1987-12-29 | Fumio Kiyota | Heat-resistant, wear-resistant, and high-strength aluminum alloy powder and body shaped therefrom |
-
1983
- 1983-07-21 FR FR8312381A patent/FR2549493B1/en not_active Expired
-
1984
- 1984-01-12 US US06/570,257 patent/US4575450A/en not_active Expired - Fee Related
- 1984-07-18 DE DE8484420126T patent/DE3461256D1/en not_active Expired
- 1984-07-18 EP EP84420126A patent/EP0133144B1/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6749926B1 (en) | 1999-07-23 | 2004-06-15 | Nippon Sheet Glass Company, Limited | Curved glass sheet for vehicle window |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0133144A1 (en) | 1985-02-13 |
| FR2549493A1 (en) | 1985-01-25 |
| US4575450A (en) | 1986-03-11 |
| FR2549493B1 (en) | 1987-07-31 |
| DE3461256D1 (en) | 1987-01-02 |
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