EP0351327A1 - Method for fabrication of thixotrope metallic products by continuous casting - Google Patents

Method for fabrication of thixotrope metallic products by continuous casting Download PDF

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Publication number
EP0351327A1
EP0351327A1 EP89420240A EP89420240A EP0351327A1 EP 0351327 A1 EP0351327 A1 EP 0351327A1 EP 89420240 A EP89420240 A EP 89420240A EP 89420240 A EP89420240 A EP 89420240A EP 0351327 A1 EP0351327 A1 EP 0351327A1
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Prior art keywords
cold zone
zone
mold
axis
wall
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German (de)
French (fr)
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EP0351327B1 (en
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Jean-Luc Meyer
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Rio Tinto France SAS
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Aluminium Pechiney SA
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/10—Supplying or treating molten metal
    • B22D11/11—Treating the molten metal
    • B22D11/114—Treating the molten metal by using agitating or vibrating means
    • B22D11/115—Treating the molten metal by using agitating or vibrating means by using magnetic fields
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/04—Continuous casting of metals, i.e. casting in indefinite lengths into open-ended moulds
    • B22D11/059—Mould materials or platings
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/10—Supplying or treating molten metal
    • B22D11/11—Treating the molten metal
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S164/00—Metal founding
    • Y10S164/90—Rheo-casting

Definitions

  • This invention relates to a process for the production by continuous casting of thixotropic metal products.
  • metal products means any product of elongated shape having a circular or polyhedral cross section constituted by a metal such as aluminum for example or one of its alloys.
  • thixotropic metal product is meant any metal composition having a non-dendritic primary solid phase and more particularly a phase with dendrites degenerated to such an extent that it is in the form of substantially spheroidal particles.
  • thixotropic products provide significant advantages over conventional products during their shaping. This is how the energy required for this operation is much lower, the cooling time is shorter, the shrinkage formed has reduced dimensions and the erosive action of the metal with respect to the dies or shaping molds. is significantly reduced.
  • the metal is poured liquid in a mold provided at one of its ends with a movable bottom and consisting of two adjacent parts of the same axis which, according to the direction of the pouring, form an upstream part called hot zone whose wall is made of a material heat insulator at least on its internal face and a downstream part known as the cold zone, the wall of which is made, at least partially, of a heat-conducting material and where the external surface is cooled by a frigopor fluid so as to cause by solidification within the liquid that said part contains, the appearance of crystals and the formation on contact of the internal surface of a solid crust sufficiently rigid to allow the gradual extraction of the product thus formed on using the movable floor, this process being characterized in that a movement is imparted to the liquid in the course of solidification ensuring at least one transfer from the cold zone to the
  • the invention consists in introducing a liquid metal into a mold composed of an upstream part constituted by a material having heat-insulating properties at least as regards its wall in contact with the metal.
  • This material can be, for example, of the type of those which are commonly used in foundry for the manufacture of chutes or nozzles. Due to the reduced heat exchanges which take place in this part, the metal maintains itself normally, that is to say without any external disturbance, at a temperature sufficient for no crystallization to occur. Hence the designation of this part by the expression "hot zone".
  • This upstream part is connected by means of a suitable joint to a downstream part which, unlike the previous one, is very good conductor of heat at least over a portion of its height located most downstream and which, because of its ability to easily evacuate the calories from the metal it contains to the outside is called the "cold zone".
  • This part is the analog of the ingot mold in a conventional continuous casting and it is within it that the crystallization process is initiated and that from the wall cooled externally cooled by a coolant fluid a crystalline envelope sufficiently rigid to allow progressive extraction using the movable bottom of the cast product, while inside this envelope delimited by the "solidification front", surface having the general profile of a meniscus whose apex is oriented towards the 'downstream, a "swamp" is formed, consisting of a mixture of liquid and generally dendritic solid particles, particles which will gradually integrate into the solidification front and allow the solid part to develop and the flow to progress.
  • the movement of the particles takes place in at least loops, the assembly of which generates a torus with an axis substantially coincident with the axis of the mold.
  • These loops are located in meridian planes of the mold, that is to say passing through its axis, and each is entirely contained in the half-plane limited by said axis.
  • the portion of the loop along which the liquid passes from the cold zone to the hot zone is closest to the axis, the portion corresponding to the return being close to the wall of the mold.
  • two types of means are used: One of them is to pass a single-phase electric current of frequency less than or equal to the industrial frequency within the downstream part of the mold which is known to be made at least partially by an electrically conductive material .
  • the wall of this part must have over its entire thickness and along at least one generator an insert of material insulating from electricity on either side of which are fixed current leads.
  • this part plays the role of whorl and the current which crosses it generates a magnetic field which develops electromagnetic forces generating the desired movement.
  • the internal wall of this part must be covered with an electrically insulating film so that there is no electrical continuity between said metal part and the cast metal because if this were the case it would cause a short circuit and would prevent the development of the magnetic field conducive to movement.
  • the electromagnetic forces being a function of the intensity of the current flowing in the turn, preferably used for making the downstream part of metals of low electrical resistivity but mechanical strength nevertheless compatible with the cast metal. It can be, for example, copper or aluminum and their alloys in the case where aluminum is poured.
  • the insulating film may consist of an oxide layer obtained by anodization in the case of aluminum or an enamel, or even a fluorocarbon resin for example.
  • the thickness of this film is a function of the electrical voltage under which the wall is located relative to the cast metal. We can use an oxide thickness of 1 ⁇ m for a voltage of 100 volts.
  • the downstream parts thus formed can be fitted on their internal face with a graphite ring a few millimeters thick which plays the role of lubricant with respect to the cast metal and can amplify the role of a lubricating agent with which it is sometimes necessary to coat the inner wall of the downstream part to facilitate the casting of certain metals.
  • This ring can be divided according to its generators in at least two sectors to avoid not only any Joule effect in the zone where on the contrary it is desired to cool, but also a reduction in energy which would limit the movement of the metal.
  • the other means of producing the movement of the liquid within the mold consists in placing at the outside of the downstream part of the mold at least one metal coil of axis substantially parallel to the axis of the mold and having it pass through by a single-phase current of frequency less than or equal to the industrial frequency.
  • This turn electrically insulated from the wall of said part in fact creates a magnetic field parallel to the axis of the mold which develops electromagnetic forces generating the desired movement.
  • this movement is more or less wide and a function of the intensity admitted in the turn, but it also depends on other factors such as the composition of the material constituting the wall of the cold zone or the structure of said wall.
  • a material having a resistivity greater than 5 ⁇ .cm it is preferable to use a material having a resistivity greater than 5 ⁇ .cm. It may for example be a non-magnetic stainless steel or titanium or else a ceramic provided that it has sufficient thermal conductivity.
  • the best solution not to break with the habits of the profession is to use aluminum but in the form of an alloy containing by weight about 1.8% Mn; 0.25% Cr; 0.2% Ti and 0.1% V whose resistivity is equal to 9.3 ⁇ .cm instead of less than 3 ⁇ .cm for conventional alloys.
  • This resistivity can however be increased by adding Mg up to 5% in which case, values are reached from 11 to 12 ⁇ .cm.
  • the addition of Li up to 1% or Zr up to 0.15% is also favorable.
  • the wall of the cold zone is divided along its generators into at least two sectors separated from each other by an electrical insulator such as mica, said sectors being kept assembled together by means of stainless steel pins and insulating dowels.
  • All these types of embodiment of the downstream part can also be lined on their internal wall and in the vicinity of the hot zone with a coaxial graphite ring preferably shared along its generatrices in at least two sections, all these particularities always having the aim to improve the efficiency of the electric current in its transformation into electromagnetic forces generating movement.
  • All the turns which surround the downstream part of the mold are designed and mounted so as to be able to adapt to any form of downstream part and to best respond to obtaining both optimum current-force performance. and a distribution of force within the metal which ensures movement of the liquid over the entire section and the entire height of the mold in order to cause the greatest possible degeneration of the dendrites on the greatest possible number of crystals.
  • the cold zone may be surrounded by magnetic yoke elements formed from metal sheets electrically isolated from one another and situated in planes passing through it. mold axis.
  • the cooling of the cold zone is obtained as is known either by means of fluid boxes integrated into the external wall of said zone or by direct application of a peripheral fluid blade on said wall.
  • the fluid is adjusted in flow and / or in temperature while modifying in the case of direct cooling the impact surfaces of the fluid blade.
  • the hot zone or at least its part closest to the cold zone can be surrounded by a sheath in which circulates a gas under pressure and chemically inert with respect to the cast metal because under these conditions it is found that the cast product then presents a better surface appearance.
  • FIG. 1 represents a vertical half-section passing through the axis of a mold applicable to the invention.
  • an upstream part 1 made of a heat insulating material which encloses the liquid metal 2 and forms the hot zone
  • a downstream part 3 made of heat conducting material fitted internally with a graphite ring 4 and cooled externally by a film 5 of water from a supply box 6 which forms the cold zone.
  • the metal solidifies along the front 7 to give the product 8 cast.
  • a coil 9 supplied with alternating current surrounds the cold zone and creates a magnetic field which induces electromagnetic forces so that the liquid metal moves along arrow 10 parallel to the axis of the mold towards the hot zone and returns to the cold zone along the wall of the mold according to arrow 11 causing in its movement the particles 12.
  • An example of a structure obtained at the heart of the billet examined by micrography see fig. 2 under magnification 50) makes it possible to appreciate the effectiveness of the process in obtaining a structure with degenerate dendrites.
  • An alloy 2124 (according to the standards of the Aluminum Association) was cast in the form of a billet with a diameter of 400 mm according to the method described.
  • the overall design of the tool was similar to that described in the previous example, with the exception of the current flow; in this case, it was operated through a whorl independent of the downstream part.
  • the casting speed was 40 mm / min, which is conventionally used for this billet diameter. After micrographic examination, it was found that with the exception of a peripheral zone of the order of 15 mm, the structure of the grains was particularly rounded, practically without dendrite arms and of very fine size, from the 'around 70 ⁇ m.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)
  • Mold Materials And Core Materials (AREA)
  • Compositions Of Oxide Ceramics (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Molds, Cores, And Manufacturing Methods Thereof (AREA)
  • Manufacture Of Metal Powder And Suspensions Thereof (AREA)
  • Glass Compositions (AREA)

Abstract

A method is disclosed for making thixotropic metal products by continuous casting by pouring liquid metal into a mold with a movable end and having upstream and downstream portions. The upstream portion has a wall made of a heat insulating material at least at its inner surface to form a hot zone, and the downstream portion has a wall made at least partially of a heat conducting material to form a cold zone. A movement is imparted to the solidifying liquid to cause circulation between the cold zone and the hot zone in order to bring about surface remelting of crystals formed in the cold zone and degeneration of dendrites.

Description

Cette invention est relative à un procédé de fabrication par coulée continue de produits métalliques thixotropes.This invention relates to a process for the production by continuous casting of thixotropic metal products.

Dans ce qui suit, on entend par produits métalliques tout produit de forme allongée ayant une section circulaire ou polyédrique constitué par un métal comme l'aluminium par exemple ou un de ses alliages.
Par produit métallique thixotrope, on entend toute composition métallique présentant une phase solide primaire non dendritique et plus particulière­ment une phase à dendrites dégénérées à un point tel qu'elle se présente sous forme de particules sensiblement sphéroïdales.In what follows, the term “metallic products” means any product of elongated shape having a circular or polyhedral cross section constituted by a metal such as aluminum for example or one of its alloys.
By thixotropic metal product is meant any metal composition having a non-dendritic primary solid phase and more particularly a phase with dendrites degenerated to such an extent that it is in the form of substantially spheroidal particles.

Ces produits thixotropes procurent lors de leur mise en forme des avantages importants par rapport aux produits classiques. C'est ainsi que l'énergie nécessaire à cette opération est beaucoup plus faible, la durée de refroidiss­ement plus courte, la retassure formée a des dimensions réduites et l'action érosive du métal vis à vis des filières ou des moules de mise en forme est sensiblement atténuée.These thixotropic products provide significant advantages over conventional products during their shaping. This is how the energy required for this operation is much lower, the cooling time is shorter, the shrinkage formed has reduced dimensions and the erosive action of the metal with respect to the dies or shaping molds. is significantly reduced.

De nombreux brevets enseignent des moyens d'obtention de tels produits. On peut citer par exemple, l'US 3948650 et son correspondant français n° 2141979 qui décrit un procédé de coulée consistant à élever la températu­re d'une composition métallique jusqu'à ce qu'elle soit à l'état liquide, à refroidir pour provoquer une certaine solidification du liquide et à agiter énergiquement le mélange liquide-solide jusqu'à ce qu'environ 65% en poids du mélange ainsi formé soit sous forme de solide présentant des dendrites ou nodules dégénérés individuels.Many patents teach means of obtaining such products. We can cite for example, US 3948650 and its French correspondent n ° 2141979 which describes a casting process consisting in raising the temperature of a metallic composition until it is in the liquid state, in cooling for cause a certain solidification of the liquid and vigorously stir the liquid-solid mixture until about 65% by weight of the mixture thus formed is in the form of a solid having individual degenerate dendrites or nodules.

Ce procédé a été perfectionné par la suite pour devenir continu dans l'US 3902544.
Puis, suivant le processus sus-mentionné, on s'est attaché dans l'US 4434837 à réaliser un dispositif d'agitation convenable comprenant un stator à deux pôles qui crée un champ magnétique tournant se déplaçant perpendiculai­rement à l'axe du moule et génère des forces électromagnétiques dirigées tangentiellement au moule et telle qu'elles entraînent un taux de cisail­lement d'au moins 500 sec⁻¹. On a également réalisé dans l'US 4457355 un moule formé de deux parties de conductibilité thermique différente et dans l'EP 71822 un moule formé d'une succession de tôles isolantes et conductrices.This process was later perfected to become continuous in US 3902544.
Then, according to the above-mentioned process, we set out in US 4434837 to produce a suitable stirring device comprising a two-pole stator which creates a rotating magnetic field moving perpendicular to the axis of the mold and generates electromagnetic forces directed tangentially to the mold and such that they cause a shear rate of at least 500 sec⁻¹. We also carried out in US 4457355 a mold formed of two parts of different thermal conductivity and in EP 71822 a mold formed of a succession of insulating and conductive sheets.

Dans des demandes de brevet plus récentes, les améliorations ont consisté dans l'US 4482012 à utiliser un moule formé de deux chambres reliées entre elles par un joint non conducteur, dont la première joue le rôle d'échangeur de chaleur et dans l'US 4565241 on a préconisé des conditions d'agitation telles que le rapport du taux de cisaillement sur le taux de solidification soit compris entre 2.10³ et 8.10³.In more recent patent applications, improvements have consisted in US 4482012 in using a mold formed by two chambers connected to each other by a non-conductive seal, the first of which acts as a heat exchanger and in the US 4565241 stirring conditions have been recommended such that the ratio of the shear rate to the solidification rate is between 2.10³ and 8.10³.

Certes, cette voie d'obtention de produits thixotropes par coulée sous agitation a conduit à des produits convenables.
Toutefois, on en est arrivé dans l'art antérieur à des dispositifs mettant en oeuvre des inducteurs électriques à champ tournant chargés d'imprimer au métal en cours de solidification de grandes vitesses de rotation dans un plan perpendiculaire à l'axe du moule de façon à le brasser et casser les dendrites pour donner aux cristaux la forme de particules sphéroïdales, c'est-à-dire que la structure thixotrope est obtenue par un effet mécanique.Admittedly, this route of obtaining thixotropic products by stirring casting has led to suitable products.
However, we have arrived in the prior art at devices using electrical inductors with rotating field responsible for printing metal during solidification at high rotational speeds in a plane perpendicular to the axis of the mold so to stir it and break the dendrites to give the crystals the shape of spheroidal particles, that is to say that the thixotropic structure is obtained by a mechanical effect.

De plus, comme l'indique l'US 4482012, il est indispensable de pouvoir contrôler étroitement l'extraction de chaleur de la masse en cours de solidification. D'où la réalisation d'échangeurs de chaleur fragiles et compliqués à régler formés par un assemblage savant de parties thermiquement conductrices et isolantes qui amènent le métal à une température la plus proche possible du liquidus tout en évitant la solidification sur les parois du moule.In addition, as US 4482012 indicates, it is essential to be able to closely control the heat extraction from the mass during solidification. Hence the realization of fragile and complicated to regulate heat exchangers formed by a clever assembly of thermally conductive and insulating parts which bring the metal to a temperature as close as possible to the liquidus while avoiding solidification on the walls of the mold.

C'est pourquoi la demanderesse s'intéressant à la fabrication de produits thixotropes mais cherchant à s'affranchir des contingences des techniques de l'art antérieur a mis au point un procédé de coulée dans lequel, selon l'invention, on verse le métal liquide dans un moule muni à l'une de ses extrémités d'un fond mobile et constitué de deux parties adjacentes de même axe qui, suivant le sens de la coulée, forment une partie amont dite zone chaude dont la paroi est réalisée en un matériau isolant de la chaleur du moins sur sa face interne et une partie aval dite zone froide dont la paroi est réalisée, au moins partiellement, en un matériau conducteur de la chaleur et où la surface externe est refroidie par un fluide frigopor­ teur de façon à provoquer par solidification au sein du liquide que contient ladite partie, l'apparition de cristaux et la formation au contact de la surface interne d'une croûte solide suffisamment rigide pour permettre l'extraction progressive du produit ainsi formé à l'aide du fond mobile, ce procédé étant caractérisé en ce que l'on imprime au liquide en cours de solidification un mouvement assurant au moins un transfert de la zone froide vers la zone chaude et vice-versa de durée ≦ 1 seconde pour provo­quer une refusion en surface des cristaux qu'il contient et assurer une dégénérescence des dendrites.This is why the applicant interested in the manufacture of thixotropic products but seeking to overcome the contingencies of the techniques of the prior art has developed a casting process in which, according to the invention, the metal is poured liquid in a mold provided at one of its ends with a movable bottom and consisting of two adjacent parts of the same axis which, according to the direction of the pouring, form an upstream part called hot zone whose wall is made of a material heat insulator at least on its internal face and a downstream part known as the cold zone, the wall of which is made, at least partially, of a heat-conducting material and where the external surface is cooled by a frigopor fluid so as to cause by solidification within the liquid that said part contains, the appearance of crystals and the formation on contact of the internal surface of a solid crust sufficiently rigid to allow the gradual extraction of the product thus formed on using the movable floor, this process being characterized in that a movement is imparted to the liquid in the course of solidification ensuring at least one transfer from the cold zone to the hot zone and vice versa of duration ≦ 1 second to cause reflow on the surface of the crystals it contains and ensure degeneration of the dendrites.

Ainsi, l'invention consiste à introduire un métal liquide dans un moule composé d'une partie amont constituée par un matériau ayant des propriétés calorifuges du moins en ce qui concerne sa paroi en contact avec le métal. Ce matériau peut être, par exemple, du type de ceux qui sont utilisés couramment en fonderie pour la confection de goulottes ou de busettes. En raison des échanges thermiques réduits qui ont lieu dans cette partie, le métal se maintient normalement, c'est-à-dire sans aucune perturbation extérieure, a une température suffisante pour qu'aucune cristallisation ne se produise. D'où la désignation de cette partie par l'expression "zone chaude".
Cette partie amont est reliée par l'intermédiaire d'un joint convenable à une partie aval laquelle, au contraire de la précédente, est très bonne conductrice de la chaleur au moins sur une portion de sa hauteur située la plus en aval et qui du fait de son aptitude à évacuer facilement les calories du métal qu'elle contient vers l'extérieur est désigné sous l'appel­lation de "zone froide". Cette partie est l'analogue de la lingotière dans une coulée classique continue et c'est en son sein que se déclenche le processus de cristallisation et que se développe à partir de la paroi refroidie extérieurement par un fluide frigoporteur une enveloppe cristalli­ne suffisamment rigide pour permettre l'extraction progressive à l'aide du fond mobile du produit coulé, tandis qu'à l'intérieur de cette enveloppe délimitée par le "front de solidification", surface ayant le profil général d'un ménisque dont le sommet est orienté vers l'aval, se forme "un marais" constitué par un mélange de liquide et de particules solides généralement dendritiques, particules qui vont s'intégrer progressivement au front de solidification et permettront à la partie solide de se développer et à la coulée de progresser.
On a ainsi un ensemble zone chaude-zone froide contenant respectivement un liquide et un liquide chargé en particules dendritiques et c'est à ce liquide que l'on imprime un mouvement tel que les particules soient entraînées vers la zone chaude. Dans ces conditions, on constate que les particules perdent au moins une partie de leurs ramifications et ont tendan­ce à se sphéroïdiser. Toutefois, pour que ce phénomène soit suffisamment important, il faut que le transfert d'une zone à l'autre se fasse rapidement et en tout cas pendant une durée inférieure ou égale à une seconde. Plus petite est cette durée, meilleur est le taux de dégénérescence des dendri­tes. Il est évident que ce mouvement de la zone froide vers la zone chaude s'accompagne d'un mouvement inverse de sorte que les particules reviennent dans la zone d'origine et peuvent alors effectuer un nouveau cycle. Au cours de ces cycles, les particules sont amenées à entrer en contact avec le front de solidification et certaines à s'y accrocher de sorte que le produit obtenu se trouve formé au moins en partie de particules dégénérées qui vont lui conférer au moins partiellement des propriétés thixotropes.Thus, the invention consists in introducing a liquid metal into a mold composed of an upstream part constituted by a material having heat-insulating properties at least as regards its wall in contact with the metal. This material can be, for example, of the type of those which are commonly used in foundry for the manufacture of chutes or nozzles. Due to the reduced heat exchanges which take place in this part, the metal maintains itself normally, that is to say without any external disturbance, at a temperature sufficient for no crystallization to occur. Hence the designation of this part by the expression "hot zone".
This upstream part is connected by means of a suitable joint to a downstream part which, unlike the previous one, is very good conductor of heat at least over a portion of its height located most downstream and which, because of its ability to easily evacuate the calories from the metal it contains to the outside is called the "cold zone". This part is the analog of the ingot mold in a conventional continuous casting and it is within it that the crystallization process is initiated and that from the wall cooled externally cooled by a coolant fluid a crystalline envelope sufficiently rigid to allow progressive extraction using the movable bottom of the cast product, while inside this envelope delimited by the "solidification front", surface having the general profile of a meniscus whose apex is oriented towards the 'downstream, a "swamp" is formed, consisting of a mixture of liquid and generally dendritic solid particles, particles which will gradually integrate into the solidification front and allow the solid part to develop and the flow to progress.
We thus have a hot zone-cold zone containing respectively a liquid and a liquid loaded with dendritic particles and it is to this liquid that a movement is imparted such that the particles are entrained towards the hot zone. Under these conditions, it is found that the particles lose at least part of their ramifications and tend to spheroidize. However, for this phenomenon to be significant enough, the transfer from one zone to the other must take place quickly and in any case for a duration less than or equal to one second. The shorter the duration, the better the degeneration rate of dendrites. It is obvious that this movement from the cold zone to the hot zone is accompanied by a reverse movement so that the particles return to the original zone and can then carry out a new cycle. During these cycles, the particles are brought into contact with the solidification front and some of them cling to it so that the product obtained is formed at least in part from degenerate particles which will at least partially give it thixotropic properties.

De préférence, le mouvement des particules s'effectue suivant au moins des boucles dont l'ensemble génère un tore d'axe sensiblement confondu avec l'axe du moule. Ces boucles sont situées dans des plans méridiens du moule, c'est-à-dire passant par son axe, et chacune est entièrement contenue dans le demi plan limité par ledit axe. De préférence, la portion de boucle suivant laquelle le liquide passe de la zone froide vers la zone chaude est la plus proche de l'axe, la portion correspondant au retour étant voisine de la paroi du moule.Preferably, the movement of the particles takes place in at least loops, the assembly of which generates a torus with an axis substantially coincident with the axis of the mold. These loops are located in meridian planes of the mold, that is to say passing through its axis, and each is entirely contained in the half-plane limited by said axis. Preferably, the portion of the loop along which the liquid passes from the cold zone to the hot zone is closest to the axis, the portion corresponding to the return being close to the wall of the mold.

A partir de cette description, on peut constater deux différences fondamen­tales entre le procédé de l'art antérieur et celui de l'invention. Dans le premier, la circulation du liquide s'effectue par rotation autour de l'axe du moule, c'est-à-dire dans un plan perpendiculaire audit axe et la dégénérescence est obtenue par cassage des cristaux maintenus à une température sensiblement constante. Dans le deuxième, la circulation princi­pale du liquide s'effectue parallèlement à l'axe du moule et la dégénéres­cence résulte d'un phénomène thermique et non mécanique. Cela permet de s'affranchir de la contingence du maintien des cristaux à une température toujours voisine du liquidus et donc de l'utilisation d'échangeurs de chaleur sophistiqués d'un réglage délicat et également de recourir à des moyens de production de mouvement beaucoup plus simples que les généra­teurs à champ tournant.From this description, two fundamental differences can be seen between the process of the prior art and that of the invention. In the first, the circulation of the liquid takes place by rotation around the axis of the mold, that is to say in a plane perpendicular to said axis and the degeneration is obtained by breaking the crystals maintained at a substantially constant temperature. In the second, the main circulation of the liquid takes place parallel to the axis of the mold and the degeneration results from a thermal and not mechanical phenomenon. This makes it possible to get rid of the contingency of maintaining the crystals at a temperature always close to the liquidus and therefore of the use of sophisticated heat exchangers with a delicate adjustment and also to resort to means of producing much more movement. simple than rotating field generators.

De préférence, on utilise deux types de moyens :
L'un d'eux consiste à faire passer un courant électrique monophasé de fréquence inférieure ou égale à la fréquence industrielle au sein de la partie avale du moule dont on sait qu'elle est constituée au moins partiel­lement par un matériau conducteur de l'électricité. Toutefois, la paroi de cette partie doit présenter sur toute son épaisseur et suivant au moins une génératrice un insert en matériau isolant de l'électricité de part et d'autre duquel sont fixées des amenées de courant. Ainsi, cette partie joue le rôle de spire et le courant qui la traverse génère un champ magnéti­que qui développe des forces électromagnétiques engendrant le mouvement souhaité. De plus, la paroi interne de cette partie doit être recouverte d'un film isolant de l'électricité afin qu'il n'y ait pas continuité électri­que entre ladite partie métallique et le métal coulé car si c'était le cas cela entraînerait un court-circuit et empêcherait le développement du champ magnétique propice au mouvement.
Les forces électromagnétiques étant fonction de l'intensité du courant qui circule dans la spire, on utilise de préférence pour la confection de la partie aval des métaux de faible résistivité électrique mais de tenue mécanique néanmoins compatibles avec le métal coulé. Ce peut être, par exemple, le cuivre ou l'aluminium et leurs alliages dans le cas où on coule de l'aluminium.Preferably, two types of means are used:
One of them is to pass a single-phase electric current of frequency less than or equal to the industrial frequency within the downstream part of the mold which is known to be made at least partially by an electrically conductive material . However, the wall of this part must have over its entire thickness and along at least one generator an insert of material insulating from electricity on either side of which are fixed current leads. Thus, this part plays the role of whorl and the current which crosses it generates a magnetic field which develops electromagnetic forces generating the desired movement. In addition, the internal wall of this part must be covered with an electrically insulating film so that there is no electrical continuity between said metal part and the cast metal because if this were the case it would cause a short circuit and would prevent the development of the magnetic field conducive to movement.
The electromagnetic forces being a function of the intensity of the current flowing in the turn, preferably used for making the downstream part of metals of low electrical resistivity but mechanical strength nevertheless compatible with the cast metal. It can be, for example, copper or aluminum and their alloys in the case where aluminum is poured.

Mais on a aussi constaté qu'on pouvait utiliser des assemblages constitués de différents matériaux dans lesquels la portion la plus proche de la partie amont est faite sinon avec un matériau isolant du moins en un maté­riau moins bon conducteur de l'électricité tel qu'un acier inoxydable, par exemple. Dans ces conditions, le mouvement du liquide peut être amplifié.But we have also found that we could use assemblies made of different materials in which the portion closest to the upstream part is made if not with an insulating material at least in a material less good conductor of electricity such as stainless steel, for example. Under these conditions, the movement of the liquid can be amplified.

Quant au film isolant, il peut être constitué par une couche d'oxyde obtenue par anodisation dans le cas de l'aluminium ou un émail, ou encore une résine fluorocarbonée par exemple. L'épaisseur de ce film est fonction de la tension électrique sous laquelle se trouve la paroi par rapport au métal coulé. On peut se baser sur une épaisseur d'oxyde de 1 µm pour une tension de 100 volts.As for the insulating film, it may consist of an oxide layer obtained by anodization in the case of aluminum or an enamel, or even a fluorocarbon resin for example. The thickness of this film is a function of the electrical voltage under which the wall is located relative to the cast metal. We can use an oxide thickness of 1 µm for a voltage of 100 volts.

Les parties aval ainsi constituées peuvent être équipées sur leur face interne d'une bague de graphite de quelques millimètres d'épaisseur qui joue le rôle de lubrifiant vis à vis du métal coulé et peut amplifier le rôle d'un agent de lubrification dont il s'avère parfois nécessaire de revêtir paroi interne de la partie avale pour faciliter la coulée de certains métaux.The downstream parts thus formed can be fitted on their internal face with a graphite ring a few millimeters thick which plays the role of lubricant with respect to the cast metal and can amplify the role of a lubricating agent with which it is sometimes necessary to coat the inner wall of the downstream part to facilitate the casting of certain metals.

Cette bague peut être partagée suivant ses génératrices en au moins deux secteurs pour éviter non seulement tout effet Joule dans la zone où au contraire on souhaite refroidir, mais aussi une réduction de l'énergie qui limiterait le mouvement du métal.This ring can be divided according to its generators in at least two sectors to avoid not only any Joule effect in the zone where on the contrary it is desired to cool, but also a reduction in energy which would limit the movement of the metal.

D'une manière tout à fait particulière, on peut utiliser une bague présen­tant un insert placé en regard de l'insert de la partie aval ; dans ce cas, on évite également l'effet Joule mais, on peut alors fretter directe­ment la bague sur la paroi interne de ladite partie sans avoir besoin d'un film isolant intermédiaire.In a very particular way, one can use a ring having an insert placed opposite the insert of the downstream part; in this case, the Joule effect is also avoided, but the ring can then be shrunk directly onto the internal wall of said part without the need for an intermediate insulating film.

L'autre moyen de production du mouvement du liquide au sein du moule consis­te à placer à l'extérieur de la partie aval du moule au moins une spire métallique d'axe sensiblement parallèle à l'axe du moule et à la faire parcourir par un courant monophasé de fréquence inférieure ou égale à la fréquence industrielle. Cette spire isolée électriquement de la paroi de ladite partie crée en effet un champ magnétique parallèle à l'axe du moule qui développe des forces électromagnétiques engendrant le mouvement souhaité. Certes, ce mouvement est plus ou moins ample et fonction de l'intensité admise dans la spire mais il dépend également d'autres facteurs tels que la composition du matériau constituant la paroi de la zone froide ou la structure de ladite paroi.The other means of producing the movement of the liquid within the mold consists in placing at the outside of the downstream part of the mold at least one metal coil of axis substantially parallel to the axis of the mold and having it pass through by a single-phase current of frequency less than or equal to the industrial frequency. This turn electrically insulated from the wall of said part in fact creates a magnetic field parallel to the axis of the mold which develops electromagnetic forces generating the desired movement. Admittedly, this movement is more or less wide and a function of the intensity admitted in the turn, but it also depends on other factors such as the composition of the material constituting the wall of the cold zone or the structure of said wall.

Selon le premier facteur, il est préférable d'utiliser un matériau ayant une résistivité supérieure à 5 µΩ.cm. Ce peut être par exemple un acier inoxydable amagnétique ou du titane ou encore une céramique pour autant qu'elle ait une conductibilité thermique suffisante. Dans le cas de la coulée de l'aluminium, la meilleure solution pour ne pas rompre avec les habitudes de la profession est d'utiliser, de l'aluminium mais sous forme d'un alliage contenant en poids environ 1,8% Mn; 0,25% Cr; 0,2% Ti et 0,1% V dont la résistivité est égale à 9,3 µΩ.cm au lieu de moins de 3 µΩ.cm pour les alliages classiques. Cette résistivité peut cependant être augmentée par ajout de Mg jusqu'à 5% auquelcas, on atteint des valeurs de 11 à 12 µΩ.cm. L'ajout de Li jusqu'à 1% ou de Zr jusqu'à 0,15% est également favorable.According to the first factor, it is preferable to use a material having a resistivity greater than 5 µΩ.cm. It may for example be a non-magnetic stainless steel or titanium or else a ceramic provided that it has sufficient thermal conductivity. In the case of casting aluminum, the best solution not to break with the habits of the profession is to use aluminum but in the form of an alloy containing by weight about 1.8% Mn; 0.25% Cr; 0.2% Ti and 0.1% V whose resistivity is equal to 9.3 µΩ.cm instead of less than 3 µΩ.cm for conventional alloys. This resistivity can however be increased by adding Mg up to 5% in which case, values are reached from 11 to 12 µΩ.cm. The addition of Li up to 1% or Zr up to 0.15% is also favorable.

D'autres solutions consistent à utiliser des matériaux composites tels que par exemple un acier inoxydable revêtu intérieurement par une mince couche d'aluminium.Other solutions consist in using composite materials such as for example stainless steel coated internally with a thin layer of aluminum.

Suivant le deuxième facteur, pour réduire l'intensité nécessaire au mouve­ment, on partage la paroi de la zone froide suivant ses génératrices en au moins deux secteurs séparés l'un de l'autre par un isolant électrique tel que le mica, lesdits secteurs étant maintenus assemblés entre eux au moyen de goupilles en acier inox et de chevilles en matière isolante.According to the second factor, to reduce the intensity necessary for movement, the wall of the cold zone is divided along its generators into at least two sectors separated from each other by an electrical insulator such as mica, said sectors being kept assembled together by means of stainless steel pins and insulating dowels.

Tous ces types de réalisation de la partie aval peuvent également être garnis sur leur paroi interne et au voisinage de la zone chaude d'une bague en graphite coaxiale de préférence partagée suivant ses génératrices en au moins deux sections, toutes ces particularités ayant toujours pour but d'améliorer l'efficacité du courant électrique dans sa transformation en forces électromagnétiques génératrices de mouvement.All these types of embodiment of the downstream part can also be lined on their internal wall and in the vicinity of the hot zone with a coaxial graphite ring preferably shared along its generatrices in at least two sections, all these particularities always having the aim to improve the efficiency of the electric current in its transformation into electromagnetic forces generating movement.

Toutes les spires qui entourent la partie aval du moule sont conçues et montées de manière à pouvoir s'adapter à n'importe quelle forme de partie aval et à répondre au mieux à l'obtention à la fois d'un rendement courant-force optimum et d'une distribution de la force au sein du métal qui assure un mouvement du liquide sur toute la section et toute la hauteur du moule afin de provoquer la plus grande dégénérescence possible des dendrites sur le plus grand nombre possible de cristaux.All the turns which surround the downstream part of the mold are designed and mounted so as to be able to adapt to any form of downstream part and to best respond to obtaining both optimum current-force performance. and a distribution of force within the metal which ensures movement of the liquid over the entire section and the entire height of the mold in order to cause the greatest possible degeneration of the dendrites on the greatest possible number of crystals.

C'est ainsi que ces spires peuvent être déplacées parallèlement à l'axe du moule ou encore formées par un assemblage d'éléments démontables capables de circonscrire des moules de toute section de façon équidistante, ou à des distances différentes. Ces assemblages conviennent parfaitement dans le cas de produits de section rectangulaire.Thus these turns can be moved parallel to the axis of the mold or formed by an assembly of removable elements capable of circumscribing molds of any section equidistantly, or at different distances. These assemblies are perfectly suitable for products with a rectangular section.

D'autres particularités peuvent être incluses dans l'invention ayant tou­jours pour but d'améliorer l'efficacité du mouvement du métal tels que l'adjonction autour de la zone chaude d'au moins une spire métallique parcourue par un courant électrique, cette ou ces spires étant reliées soit à celle(s) de la zone froide, soit à un générateur de courant d'intensi­té, de fréquence et/ou de phase différente du courant alimentant la (ou les) spire(s) de la zone froide.Other particularities can be included in the invention always aiming to improve the efficiency of the movement of the metal such as the addition around the hot zone of at least one metallic turn traversed by an electric current, this or these turns being connected either to that (s) of the cold zone, or to a current generator of intensity, frequency and / or phase different from the current supplying the coil (s) of the cold zone.

En vue de canaliser le champ magnétique créé par la (ou les) spire(s), la zone froide peut être entourée d'éléments de culasse magnétique formés de feuilles métalliques isolées électriquement les unes des autres et situées dans des plans passant par l'axe du moule.In order to channel the magnetic field created by the coil (s), the cold zone may be surrounded by magnetic yoke elements formed from metal sheets electrically isolated from one another and situated in planes passing through it. mold axis.

Le refroidissement de la zone froide est obtenu comme il est connu soit par l'intermédiaire de boîtes à fluide intégrées à la paroi externe de ladite zone ou par application directe d'une lame de fluide périphérique sur ladite paroi.The cooling of the cold zone is obtained as is known either by means of fluid boxes integrated into the external wall of said zone or by direct application of a peripheral fluid blade on said wall.

En fonction du degré de refroidissement souhaité et de sa localisation pour développer plus ou moins rapidement en un endroit donné la formation de cristaux et leur envoi dans la zone chaude à un stade d'évolution plus ou moins grand, on règle le fluide en débit et/ou en température tout en modifiant dans le cas du refroidissement direct les surfaces d'impact de la lame de fluide.Depending on the desired degree of cooling and its location to develop more or less quickly in a given place the formation of crystals and their sending into the hot zone at a more or less large stage of evolution, the fluid is adjusted in flow and / or in temperature while modifying in the case of direct cooling the impact surfaces of the fluid blade.

La zone chaude ou du moins sa partie la plus voisine de la zone froide peut être entourée d'une gaine dans laquelle circule un gaz sous pression et inerte chimiquement vis à vis du métal coulé car dans ces conditions on constate que le produit coulé présente alors un meilleur aspect de surface.The hot zone or at least its part closest to the cold zone can be surrounded by a sheath in which circulates a gas under pressure and chemically inert with respect to the cast metal because under these conditions it is found that the cast product then presents a better surface appearance.

L'invention sera mieux comprise à l'aide de la figure 1 qui représente une demi- coupe verticale passant par l'axe d'un moule applicable à l'inven­tion.
On y distingue : une partie amont 1 réalisée en un matériau isolant de la chaleur qui renferme le métal liquide 2 et forme la zone chaude, une partie aval 3 en matériau conducteur de la chaleur équipée intérieurement d'un anneau en graphite 4 et refroidie extérieurement par un film 5 d'eau issue d'une boîte 6 d'alimentation qui forme la zone froide.
Sous l'effet du refroidissement dû à l'eau le métal se solidifie suivant le front 7 pour donner le produit 8 coulé.
Une bobine 9 alimentée en courant alternatif entoure la zone froide et crée un champ magnétique qui induit des forces électromagnétiques de sorte que le métal liquide se déplace suivant la flèche 10 parallèlement à l'axe du moule vers la zone chaude et revient à la zone froide le long de la paroi du moule suivant la flèche 11 entraînant dans son mouvement les particules 12.
L'invention peut être illustrée à l'aide des exemples d'application suivants:The invention will be better understood using FIG. 1 which represents a vertical half-section passing through the axis of a mold applicable to the invention.
There are: an upstream part 1 made of a heat insulating material which encloses the liquid metal 2 and forms the hot zone, a downstream part 3 made of heat conducting material fitted internally with a graphite ring 4 and cooled externally by a film 5 of water from a supply box 6 which forms the cold zone.
Under the effect of cooling due to water, the metal solidifies along the front 7 to give the product 8 cast.
A coil 9 supplied with alternating current surrounds the cold zone and creates a magnetic field which induces electromagnetic forces so that the liquid metal moves along arrow 10 parallel to the axis of the mold towards the hot zone and returns to the cold zone along the wall of the mold according to arrow 11 causing in its movement the particles 12.
The invention can be illustrated with the aid of the following application examples:

Exemple 1Example 1

Une billette de diamètre 70 mm en alliage d'aluminium du type AS7GO,3 (c'est-à-dire contenant en poids % : Si=7 et Mg=0,3) a été réalisée selon le procédé décrit ci-dessus :
- la partie amont était formée d'un anneau en MONALITE de hauteur 50 mm
- la partie aval en aluminium était revêtue intérieurement d'une fine couche anodisée (5 µm) et d'une bague graphite sectorisée en 12 morceaux, et était fendue sur toute sa hauteur. Le courant circulait directement à travers la partie aval , à laquelle d'ailleurs deux amenées avaient été fixées de part et d'autre de la fente. La tension aux bornes de ces amenées était alors de 1,05V. La vitesse de coulée était de 200 mm/min, ce qui est classiquement utilisé pour ce diamètre de billette. Un exemple de structure obtenue à coeur de la billette examinée par micrographie (voir fig. 2 sous grossissement 50) permet de se rendre compte de l'efficacité du procédé à obtenir une structure à dendrites dégénérées.A 70 mm diameter billet of aluminum alloy of the AS7GO, 3 type (that is to say containing by weight%: Si = 7 and Mg = 0.3) was produced according to the method described above:
- the upstream part was formed by a MONALITE ring 50 mm high
- the downstream aluminum part was coated internally with a thin anodized layer (5 µm) and a graphite ring segmented into 12 pieces, and was split over its entire height. The current flowed directly through the downstream part, to which, moreover, two leads had been fixed on either side of the slot. The voltage across these leads was then 1.05V. The casting speed was 200 mm / min, which is conventionally used for this billet diameter. An example of a structure obtained at the heart of the billet examined by micrography (see fig. 2 under magnification 50) makes it possible to appreciate the effectiveness of the process in obtaining a structure with degenerate dendrites.

Exemple 2Example 2

Un alliage 2124 (suivant les normes de l'Aluminium Association) a été coulé sous forme de billette de diamètre 400 mm selon le procédé décrit. La conception globale de l'outillage était voisine de celle décrite dans l'exemple précédent, à l'exception du passage du courant; dans ce cas, il s'opérait à travers une spire indépendante de la partie avale. La vitesse de coulée était de 40 mm/min, ce qui est classiquement utilisé pour ce diamètre de billette.
Après examen micrographique, on s'est aperçu qu'à l'exception d'une zone périphérique de l'ordre de 15 mm, la structure des grains était particulière­ment arrondie, sans pratiquement de bras de dendrites et de taille très fine, de l'ordre de 70 µm.An alloy 2124 (according to the standards of the Aluminum Association) was cast in the form of a billet with a diameter of 400 mm according to the method described. The overall design of the tool was similar to that described in the previous example, with the exception of the current flow; in this case, it was operated through a whorl independent of the downstream part. The casting speed was 40 mm / min, which is conventionally used for this billet diameter.
After micrographic examination, it was found that with the exception of a peripheral zone of the order of 15 mm, the structure of the grains was particularly rounded, practically without dendrite arms and of very fine size, from the 'around 70 µm.

Example 3Example 3

Une coulée de plaques en format 800 x 300 mm en un alliage 7075 (suivant les normes de l'Aluminium Association) a été réalisée suivant le procédé décrit. Comme dans le cas de la billette ⌀ 400 mm, une spire entourait la face externe de la partie aval , à faible distance (10 mm). Cette spire était constituée en fait de 4 éléments de barre de cuivre, refroidis intérieu­rement par de l'eau, ces éléments étant reliés entre eux dans 3 des coins et reliés aux amenées de courant dans le 4ème. La vitesse de coulée était de 60 mm/min.
L'examen macrographique du produit coulé a révélé une structure homogène et fine, à l'exception des coins, qui présentaient une structure encore plus fine. Par examen micrographique, on a pu constater une modification notable de la morphologie des grains qui prenaient des formes en "patates" au lieu des formes classiques "en choux-fleur". Une attaque sélective destinée à révéler les bras des dendrites a montré que ceux-ci avaient presque complètement disparu.A casting of plates in 800 × 300 mm format in a 7075 alloy (according to the standards of the Aluminum Association) was carried out according to the process described. As in the case of the ⌀ 400 mm billet, a turn surrounded the external face of the downstream part, at a short distance (10 mm). This turn consisted in fact of 4 elements of copper bar, internally cooled by water, these elements being interconnected in 3 corners and connected to the current leads in the 4th. The casting speed was 60 mm / min.
Macrographic examination of the cast product revealed a homogeneous and fine structure, with the exception of the corners, which exhibited an even finer structure. By micrographic examination, one could note a notable modification of the morphology of the grains which took forms in "potatoes" instead of the traditional forms "in cauliflower". A selective attack intended to reveal the arms of the dendrites showed that they had almost completely disappeared.

Claims (21)

1. Procédé de fabrication par coulée continue de produits métalliques, thixotropes et, notamment, de produits en alliages d'aluminium ayant au moins partiellement une structure à dendrites dégénérées, dans lequel on verse le métal (2) liquide dans un moule muni à l'une de ses extrémités d'un fond mobile et constitué de deux parties adjacentes de même axe, qui, suivant le sens de la coulée, forment une partie amont (1) dite zone chaude dont la paroi est réalisée en un matériau isolant de la chaleur du moins sur sa face interne et une partie aval (3) dite zone froide dont la paroi est réalisée, au moins partiellement, en un matériau conduc­teur de la chaleur et où la surface externe est refroidie par un fluide caloporteur (5) de façon à provoquer, par solidification au sein du liquide que contient ladite partie, l'apparition de cristaux et la formation au contact de la surface interne d'une croûte solide suffisamment rigide pour permettre l'extraction progressive du produit (8) ainsi formé à l'aide du fond mobile, caractérisé en ce que l'on imprime au liquide en cours de solidification un mouvement assurant au moins un transfert de la zone froide vers la zone chaude (10) et vice-versa (11) de durée ≦ 1 seconde pour provoquer une refusion en surface des cristaux (12) qu'il contient et assurer une dégénérescence des dendrites.1. Manufacturing process by continuous casting of metallic, thixotropic products and, in particular, of aluminum alloy products having at least partially a structure with degenerate dendrites, in which the liquid metal (2) is poured into a mold provided with the 'one of its ends of a movable bottom and consisting of two adjacent parts of the same axis, which, according to the direction of casting, form an upstream part (1) called hot zone whose wall is made of a material insulating the heat at least on its internal face and a downstream part (3) called cold zone, the wall of which is made, at least partially, of a heat-conducting material and where the external surface is cooled by a heat-transfer fluid (5) so to cause, by solidification within the liquid that said part contains, the appearance of crystals and the formation in contact with the internal surface of a solid crust sufficiently rigid to allow progressive extraction ve of the product (8) thus formed using the movable bottom, characterized in that the liquid being solidified is imparted a movement ensuring at least one transfer from the cold zone to the hot zone (10) and vice -versa (11) of duration ≦ 1 second to cause a reflow on the surface of the crystals (12) it contains and ensure a degeneration of the dendrites. 2. Procédé selon la revendication 1, caractérisé en ce que le mouvement effectue suivant des boucles situées dans des plans méridiens dont l'en­semble génère un tore d'axe sensiblement confondu avec l'axe du moule.2. Method according to claim 1, characterized in that the movement takes place in loops located in meridian planes, the assembly of which generates a torus with an axis substantially coincident with the axis of the mold. 3. Procédé selon la revendication 1 caractérisé en ce que la paroi interne de la zone froide est recouverte d'un agent de lubrification.3. Method according to claim 1 characterized in that the internal wall of the cold zone is covered with a lubricating agent. 4. Procédé selon la revendication 1, caractérisé en ce que le mouvement est obtenu par passage d'un courant électrique monophasé de fréquence inférieure ou égale à la fréquence industrielle au sein de la partie aval du moule dont la paroi présente sur toute son épaisseur et suivant au moins une génératrice un insert en matériau isolant de l'électricité de part et d'autre duquel sont fixées des amenées de courant, ladite partie étant revêtue intérieurement d'un film isolant de l'électricité.4. Method according to claim 1, characterized in that the movement is obtained by passage of a single-phase electric current of frequency less than or equal to the industrial frequency within the downstream part of the mold whose wall has over its entire thickness and along at least one generator, an insert made of an electrically insulating material on either side of which are fixed current leads, said part being coated internally with an electrically insulating film. 5. Procédé selon la revendication 4, caractérisé en ce que la paroi interne de la zone froide est recouverte sur toute sa périphérie et au moins au voisinage de la zone chaude d'une bague en graphite de même axe que lesdites zones.5. Method according to claim 4, characterized in that the internal wall of the cold zone is covered over its entire periphery and at least in the vicinity of the hot zone with a graphite ring of the same axis as said zones. 6. Procédé selon la revendication 5 caractérisé en ce que la bague en graphite est partagée suivant ses génératrices en au moins deux secteurs.6. Method according to claim 5 characterized in that the graphite ring is divided along its generatrices in at least two sectors. 7. Procédé selon la revendication 1, caractérisé en ce que le mouvement est obtenu au moyen d'au moins une spire métallique placée à l'extérieur de la zone froide du moule dont l'axe est sensiblement parallèle à l'axe dudit moule et parcourue par un courant monophasé de fréquence inférieure ou égale à la fréquence industrielle.7. Method according to claim 1, characterized in that the movement is obtained by means of at least one metal coil placed outside the cold zone of the mold whose axis is substantially parallel to the axis of said mold and traversed by a single-phase current of frequency lower or equal to the industrial frequency. 8. Procédé selon la renvendication 7, caratérisé en ce que la zone froide est constituée par un matériau solide ayant une résistivité supérieure à 5 µΩx cm.8. Method according to claim 7, characterized in that the cold zone consists of a solid material having a resistivity greater than 5 µΩx cm. 9. Procédé selon la revendication 7, caractérisé en ce que la zone froide est partagée suivant ses génératrices en au moins deux secteurs séparés l'un de l'autre par un isolant électrique.9. Method according to claim 7, characterized in that the cold zone is divided along its generators in at least two sectors separated from each other by an electrical insulator. 10. Procédé selon la revendication 7, caractérisé en ce que la zone froide est constituée par un assemblage de différents matériaux.10. Method according to claim 7, characterized in that the cold zone is constituted by an assembly of different materials. 11. Procédé selon la revendication 7, caractérsé en ce que la paroi interne de la zone froide est recouverte sur toute sa périphérie et au moins au voisinage de la zone chaude d'une bague en graphite de même axe que lesdites zones.11. Method according to claim 7, characterized in that the internal wall of the cold zone is covered over its entire periphery and at least in the vicinity of the hot zone with a graphite ring of the same axis as said zones. 12. Procédé selon la revendication 11 caractérisé en ce que la bague en graphite est partagée suivant ses génératrices en au moins deux secteurs.12. Method according to claim 11 characterized in that the graphite ring is divided along its generatrices in at least two sectors. 13. Procédé selon la revendication 7, caractérisé en ce que l'on déplace la (ou les) spire(s) parallèlement à l'axe du moule.13. Method according to claim 7, characterized in that one moves (or the) turn (s) parallel to the axis of the mold. 14. Procédé selon la revendication 7 caractérisé en ce que l'on règle la distance de la (ou des) spire(s) par rapport à la paroi externe de la zone froide.14. The method of claim 7 characterized in that one adjusts the distance of the (or) turn (s) relative to the outer wall of the cold zone. 15. Procédé selon la revendication 1, caractérisé en ce que la zone chaude renferme au moins une spire métallique alimentée en courant électrique.15. Method according to claim 1, characterized in that the hot zone contains at least one metal turn supplied with electric current. 16. Procédé selon les revendications 4 et 15, caractérisé en ce que la spire est reliée à la zone froide.16. Method according to claims 4 and 15, characterized in that the turn is connected to the cold zone. 17. Procédé selon la revendication 4, caractérisé en ce que la zone froide est entourée d'éléments de culasse magnétique feuilletés dont les feuilles sont situées dans des plans passant par l'axe des zones.17. The method of claim 4, characterized in that the cold zone is surrounded by laminated magnetic yoke elements whose sheets are located in planes passing through the axis of the zones. 18. Procédé selon la revendication 1, caractérisé en ce que le refroidisse­ment de la zone froide est obtenu à l'aide d'un fluide frigoporteur de débit variable.18. The method of claim 1, characterized in that the cooling of the cold zone is obtained using a refrigerant fluid of variable flow. 19. Procédé selon la revendication 1, caractérisé en ce que le refroidisse­ment de la zone froide est obtenu à l'aide d'un fluide frigoporteur de température variable.19. The method of claim 1, characterized in that the cooling of the cold zone is obtained using a coolant of variable temperature. 20. Procédé selon la revendication 1, caractérisé en ce que le refroidisse­ment de la zone froide est obtenu à l'aide d'un fluide frigoporteur qui refroidit localement ladite zone.20. The method of claim 1, characterized in that the cooling of the cold zone is obtained using a coolant which locally cools said zone. 21. Procédé selon la revendication 1 caractérisé en ce que l'on injecte un gaz sous pression au niveau de la zone froide.21. The method of claim 1 characterized in that a gas is injected under pressure at the cold zone.
EP89420240A 1988-07-07 1989-07-05 Method for fabrication of thixotrope metallic products by continuous casting Expired - Lifetime EP0351327B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT89420240T ATE72527T1 (en) 1988-07-07 1989-07-05 PROCESS FOR THE MANUFACTURE OF THIXOTROPIC METALLIC PRODUCTS BY CONTINUOUS CASTING.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8809616A FR2634677B1 (en) 1988-07-07 1988-07-07 PROCESS FOR THE MANUFACTURE BY CONTINUOUS CASTING OF THIXOTROPIC METAL PRODUCTS
FR8809616 1988-07-07

Publications (2)

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EP0351327A1 true EP0351327A1 (en) 1990-01-17
EP0351327B1 EP0351327B1 (en) 1992-02-12

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US (1) US4964455A (en)
EP (1) EP0351327B1 (en)
JP (1) JPH0255650A (en)
AT (1) ATE72527T1 (en)
AU (1) AU609690B2 (en)
CA (1) CA1334474C (en)
DE (1) DE68900825D1 (en)
ES (1) ES2029382T3 (en)
FR (1) FR2634677B1 (en)
GR (1) GR3003797T3 (en)
NO (1) NO170796C (en)
NZ (1) NZ229804A (en)

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FR2656552A1 (en) * 1990-01-04 1991-07-05 Pechiney Aluminium PROCESS FOR THE PRODUCTION OF THIXOTROPIC METALLIC PRODUCTS BY CONTINUOUS CASTING WITH ELECTROMAGNETIC CURRENT POLYPHASE CURING.
FR2758101A1 (en) * 1997-01-09 1998-07-10 Charles Vives Refining microstructure of metals continuously cast by Hot Top
FR2761624A1 (en) * 1997-04-07 1998-10-09 Charles Vives Refining microstructure of metals continuously cast by Hot Top technique
AU715447B2 (en) * 1996-03-20 2000-02-03 Aluminium Pechiney Thixotropic aluminium-silicon-copper alloy for forming in the semisolid state

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JP2772765B2 (en) * 1994-10-14 1998-07-09 本田技研工業株式会社 Method of heating casting material for thixocasting
US5911843A (en) * 1995-04-14 1999-06-15 Northwest Aluminum Company Casting, thermal transforming and semi-solid forming aluminum alloys
US5968292A (en) * 1995-04-14 1999-10-19 Northwest Aluminum Casting thermal transforming and semi-solid forming aluminum alloys
US5571346A (en) * 1995-04-14 1996-11-05 Northwest Aluminum Company Casting, thermal transforming and semi-solid forming aluminum alloys
US5887640A (en) * 1996-10-04 1999-03-30 Semi-Solid Technologies Inc. Apparatus and method for semi-solid material production
US5881796A (en) * 1996-10-04 1999-03-16 Semi-Solid Technologies Inc. Apparatus and method for integrated semi-solid material production and casting
US6470955B1 (en) 1998-07-24 2002-10-29 Gibbs Die Casting Aluminum Co. Semi-solid casting apparatus and method
US6428636B2 (en) 1999-07-26 2002-08-06 Alcan International, Ltd. Semi-solid concentration processing of metallic alloys
US6269537B1 (en) 1999-07-28 2001-08-07 Methode Electronics, Inc. Method of assembling a peripheral device printed circuit board package
US6964199B2 (en) * 2001-11-02 2005-11-15 Cantocor, Inc. Methods and compositions for enhanced protein expression and/or growth of cultured cells using co-transcription of a Bcl2 encoding nucleic acid
US20050126737A1 (en) * 2003-12-04 2005-06-16 Yurko James A. Process for casting a semi-solid metal alloy
US20070227688A1 (en) * 2004-06-15 2007-10-04 Tosoh Smd, Inc. Continuous Casting of Copper to Form Sputter Targets
US7822522B2 (en) * 2006-05-31 2010-10-26 Techno-Sciences, Inc. (corporation) Adaptive energy absorption system for a vehicle seat
JP4907248B2 (en) * 2006-07-14 2012-03-28 三協マテリアル株式会社 Continuous casting method of Al-Si aluminum alloy
US8139364B2 (en) 2007-01-31 2012-03-20 Robert Bosch Gmbh Electronic control module assembly
JP5360591B2 (en) * 2009-01-08 2013-12-04 日本軽金属株式会社 Aluminum alloy ingot and method for producing the same
JP6105312B2 (en) * 2013-02-13 2017-03-29 リンテック株式会社 Support device and data management method

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Also Published As

Publication number Publication date
NO892807D0 (en) 1989-07-06
FR2634677A1 (en) 1990-02-02
JPH0255650A (en) 1990-02-26
US4964455A (en) 1990-10-23
DE68900825D1 (en) 1992-03-26
GR3003797T3 (en) 1993-03-16
NO892807L (en) 1990-01-08
ATE72527T1 (en) 1992-02-15
AU609690B2 (en) 1991-05-02
NO170796B (en) 1992-08-31
CA1334474C (en) 1995-02-21
JPH0338019B2 (en) 1991-06-07
FR2634677B1 (en) 1990-09-21
NZ229804A (en) 1992-04-28
EP0351327B1 (en) 1992-02-12
ES2029382T3 (en) 1992-08-01
NO170796C (en) 1992-12-09
AU3783589A (en) 1990-01-11

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