EP0528723B1 - Method for bottom pouring with controlled mould filling and mould - Google Patents

Method for bottom pouring with controlled mould filling and mould Download PDF

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Publication number
EP0528723B1
EP0528723B1 EP19920402256 EP92402256A EP0528723B1 EP 0528723 B1 EP0528723 B1 EP 0528723B1 EP 19920402256 EP19920402256 EP 19920402256 EP 92402256 A EP92402256 A EP 92402256A EP 0528723 B1 EP0528723 B1 EP 0528723B1
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EP
European Patent Office
Prior art keywords
mould
basin
sprue
level
underpressure
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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EP19920402256
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German (de)
French (fr)
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EP0528723A1 (en
Inventor
Alain Pellerier
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Automobiles Peugeot SA
Automobiles Citroen SA
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Automobiles Peugeot SA
Automobiles Citroen SA
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Publication of EP0528723A1 publication Critical patent/EP0528723A1/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/08—Features with respect to supply of molten metal, e.g. ingates, circular gates, skim gates
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D35/00—Equipment for conveying molten metal into beds or moulds

Definitions

  • the present invention relates to a molding or foundry process and also relates to a mold for carrying out a casting of liquid or molten material according to this process.
  • Molds have long been known in which a molding cavity is made, the shape of which corresponds to that of the part which it is desired to obtain.
  • a vertical conduit known as a descent well, which opens onto the upper face of the mold, is connected to the molding cavity to allow it to be filled using, for example, a molten metal.
  • the descent well is connected to the upper part or top of the molding cavity.
  • the molten metal falls directly into the cavity, which can damage the latter and cause jolts during filling, in particular because of the difficulties of evacuating the gases forming in the cavity during casting. .
  • Document GB-A-1582519 describes a molding process and a mold corresponding to the preamble of claims 1 and 5 respectively.
  • the present invention aims to provide a mold for example foundry and an improved source casting process by which the filling of the molding cavity is more regular, in order to overcome in a simple and economical manner the drawbacks encountered in prior art.
  • the vacuum tank fills up as and when it is poured, up to a given level where the supply of molten material is interrupted, this level being determined so that the quantity of molten material contained in the basin is sufficient to finish filling all the cavities of the mold.
  • step (b) further comprises the detection of the level given in the depression basin, and the control of the interruption of said supply when this level is reached.
  • the present invention also relates to a mold for implementing a so-called source casting process, of the type comprising at least one molding cavity whose shape corresponds to that of a part to be produced, and at least one downspout which extends substantially vertically from a bottom or base of said cavity with which it communicates, up to an upper part of the mold where it opens, characterized in that regulating means capable of creating a reduction in the flow pressure in the downpipe are formed in the latter and are constituted by a depression basin in the lower part of which opens the descent well by outlet orifices which are offset relative to the orifice or the orifices of entry of the well in the upper part of the basin.
  • the depression basin has a section which is greater than that of the descent well and into which the latter opens on either side.
  • the depression basin is arranged at a level substantially above that of the upper part of the molding cavity.
  • the mold is characterized in that it comprises detection means capable of determining whether a given level of molten material is reached in the vacuum tank.
  • FIG. 1 there is a foundry device 10 for the production of parts (not shown) with a liquid or molten material, according to the so-called "source” casting technique.
  • a foundry device 10 for the production of parts (not shown) with a liquid or molten material, according to the so-called "source” casting technique.
  • source casting technique
  • the example illustrated relates to foundry, the invention can also be applied to other molding techniques.
  • a ladle 20 made of refractory material containing a molten material or metal 30 such as for example a spheroidal graphite cast iron (cast iron GS).
  • the ladle 20 comprises, at the level of a wall 21 which constitutes its lower part or bottom, on the one hand a material conduit 22 and on the other hand a pouring opening 23.
  • the opening in the bottom wall 21 of the pocket 20 is constituted by a nozzle 23.
  • the reference 24 designates a movable stopper or stopper, which can move up and down in the direction of the axis of the nozzle 23. In the position illustrated in FIGS. 1 and 3, a part immersed in the metal 30 of the stopper 24 is in contact with the opening of the nozzle 23 in order to prevent the metal 30 contained in the pocket 20 from flowing through of the nozzle. On the other hand, when the stopper 24 is not in contact with the nozzle 23 (FIG. 2), the metal 30 flows out of the pocket 20 through the casting opening.
  • any other similar feeding equipment such as a pressurized oven for example, can also be used.
  • a mold 40 is arranged below the pocket of casting 20, and comes into contact with the nozzle 23.
  • This mold 40 which can be produced according to any conventional technique, for example in sand, is placed on a holding and displacement mechanism 50 of known type, and comprises at least one cavity molding 41 whose shape corresponds to that of a part to be produced.
  • FIG 2 there is shown four molding cavities 41 which are connected to each other, by their lower part or base opposite the pocket 20, using a horizontal distribution duct 42 formed in the mold.
  • a descent well designated at 43 extends substantially vertically, from the base of the cavity where the horizontal conduit 42 with which it communicates is located, to an upper part of the mold 40 where it opens facing the nozzle. 23. Obviously, it is also possible to provide several descent wells 43 in each mold, for example one per molding cavity.
  • the downcomer 43 At its junction with the distribution duct 42, that is to say at its lower end, the downcomer 43 comprises in known manner a braking chamber 43a which makes it possible to slow down the flow of metal 30 so as not to damaging the mold cavities 41.
  • a wire 33 filled with an additive such as a silicon alloy which allows to perform near the nozzle 23 a treatment of the molten metal 30, so as to improve the microstructure of the casting once solidified after cooling.
  • regulating means 60 are formed in the downcomer 43, in order to create a reduction in the pressure metal flow or pouring 30 during filling of the mold cavities 41.
  • these regulating means 60 are in particular constituted by a depression chamber 61 in the form of a basin.
  • the metal passage section in the vacuum chamber 61 (in other words the cross section to the longitudinal axis of the well 43) is significantly greater than that of the well.
  • the downpipe opens on either side of the chamber 61.
  • the downcomer 43 opens into the lower part of the vacuum tank 61 through outlet orifices 63a and 63b.
  • the upper part, facing the nozzle 23, of the well 43 opens to the upper part or top of the chamber 61 through an inlet port 63c.
  • the outlet orifices 63a, 63b are offset axially -that is to say are not facing each other-with respect to the inlet orifice 63c.
  • Such an offset arrangement of the inlet orifices makes it possible to brake the flow of metal 30 coming from the nozzle 23.
  • the number of inlet and outlet orifices is not limited to three, as long as provision is made an axial misalignment capable of breaking the flow in the chamber 61.
  • the regulating means 60 are formed in the mold 40, so that the vacuum chamber 61 is above the top of the cavities 41.
  • the outlet orifices 63a and 63b are arranged in the mold at a level A which is higher than the level B of the top of the cavities 41.
  • a bent conduit 44 is formed in the mold 40.
  • One end of this conduit opens, similarly to the well 43, at the upper part or face of the mold 40.
  • the other end of the conduit 44 communicates with one of the molding cavities 41, at a level C which is substantially below the level B corresponding to the top of the cavities 41.
  • a device 70 for detecting or aiming by optical fiber for example is placed in line with the mold 40, facing the conduit 44.
  • the conduit 44 which therefore acts as a viewing conduit.
  • a light beam 74 emitted by the device 70 is reflected again towards the latter so as to indicate a filling of the cavities 41 up to level C.
  • other principles of detection can be chosen.
  • FIG. 1 also shows a detector 80 which makes it possible to permanently measure the level of metal 30 in the pocket 20.
  • This detector 80 may advantageously include a laser beam emitter 81 and be connected to means making it possible to keep the level constant (designated in D in Figure 2) of metal 30 in the ladle.
  • the cross section of the opening of the nozzle 23 is greater than that of the well 43 into which it opens.
  • the reduction in cross-section between the nozzle 23 and the well 43 allows impurities 25 to be fixed during the pouring of the metal 30 on the internal walls of the nozzle, without causing significant irregularities in flow or jolts. in the flow.
  • step (a) of preparation of the mold 40 further comprises the formation in the downhole 43 of regulating means 60 capable, during step (b) of casting, to create a reduction the flow pressure of the molten material 30 inside the well 43.
  • step (b) the vacuum tank 61 fills as it is poured up to a given level which is illustrated at E in the figure. 2.
  • the supply of molten material 30 is interrupted by placing the stopper 24 in the position visible in FIG. 3.
  • step (b) further comprises the detection of the given level E in the depression basin 61, and the control of the interruption of said supply when this level E is reached.
  • this detection is done indirectly by the detection of level C using the device 70, the levels C and E being determined so that when one is reached, the other is also reached.

Description

La présente invention se rapporte à un procédé de moulage ou de fonderie et concerne également un moule pour effectuer une coulée de matériau liquide ou en fusion suivant ce procédé.The present invention relates to a molding or foundry process and also relates to a mold for carrying out a casting of liquid or molten material according to this process.

On connait depuis longtemps des moules dans lesquels est réalisée une cavité de moulage dont la forme correspond à celle de la pièce que l'on désire obtenir. Un conduit vertical dit puits de descente, qui débouche sur la face supérieure du moule, est relié à la cavité de moulage pour permettre son remplissage à l'aide par exemple d'un métal en fusion.Molds have long been known in which a molding cavity is made, the shape of which corresponds to that of the part which it is desired to obtain. A vertical conduit, known as a descent well, which opens onto the upper face of the mold, is connected to the molding cavity to allow it to be filled using, for example, a molten metal.

Suivant une technique dite de coulée "en chute", le puits de descente est raccordé à la partie supérieure ou sommet de la cavité de moulage. Avec un tel puits, le métal en fusion chute directement dans la cavité, ce qui peut endommager cette dernière et provoquer des à-coups lors du remplissage, notamment à cause des difficultés d'évacuation des gaz se formant dans la cavité lors de la coulée.According to a so-called "falling" casting technique, the descent well is connected to the upper part or top of the molding cavity. With such a well, the molten metal falls directly into the cavity, which can damage the latter and cause jolts during filling, in particular because of the difficulties of evacuating the gases forming in the cavity during casting. .

Afin d'améliorer le dégazage et de réduire les à-coups lors du remplissage, on a prévu dans l'art antérieur de raccorder le puits de descente à la base d'une ou plusieurs cavités de moulage pour que le remplissage s'effectue par le bas. Cette technique dite de coulée "en source" oblige cependant à freiner le métal en fusion en bas du puits, afin de diminuer la pression avec laquelle le métal pénètre dans la cavité, surtout en début de coulée, puisque cette pression correspond au moins à la hauteur de métal dans le puits de descente.In order to improve degassing and reduce jolts during filling, provision has been made in the prior art to connect the downpipe to the base of one or more molding cavities so that filling is carried out by the bottom. This so-called "source" casting technique, however, requires braking the molten metal at the bottom of the well, in order to reduce the pressure with which the metal enters the cavity, especially at the start of casting, since this pressure corresponds at least to the height of metal in the downpipe.

On comprend donc que suivant la coulée "en source", la pression dans le puits de descente varie durant le remplissage de la cavité de moulage, de sorte que des risques d'endommagement du puits de descente persistent en début de coulée et que la fin du remplissage, où la pression est réduite, ne permet pas d'obtenir une bonne précision de la pièce de fonderie.It can therefore be understood that, depending on the "source" flow, the pressure in the downpipe varies during the filling the molding cavity, so that risks of damage to the downhole persist at the start of casting and that the end of filling, where the pressure is reduced, does not allow good accuracy of the workpiece to be obtained foundry.

Dans le document GB-A-1582519, sont décrits un procédé de moulage et un moule correspondant au préambule des revendications 1 et 5 respectivement.Document GB-A-1582519 describes a molding process and a mold corresponding to the preamble of claims 1 and 5 respectively.

La présente invention a pour but de proposer un moule par exemple de fonderie ainsi qu'un procédé de coulée en source améliorés grâce auxquels le remplissage de la cavité de moulage est plus régulier, afin de pallier de façon simple et économique les inconvénients rencontrés dans l'art antérieur.The present invention aims to provide a mold for example foundry and an improved source casting process by which the filling of the molding cavity is more regular, in order to overcome in a simple and economical manner the drawbacks encountered in prior art.

A cet effet, l'un des objets de l'invention est un procédé de moulage pour la réalisation d'une pièce selon la technique de coulée dite en source, et consistant à :

  • (a) préparer un moule comprenant au moins une cavité de moulage de forme correspondant à celle de la pièce à réaliser, ainsi qu'au moins un puits de descente qui s'étend sensiblement à la verticale depuis une partie inférieure ou base de ladite cavité, avec laquelle il communique, jusqu'à une partie supérieure du moule où il débouche ; et
  • (b) couler un matériau liquide ou en fusion dans le puits de descente jusqu'au remplissage au moins de la cavité,
caractérisé en ce que l'étape (a) de préparation du moule comprend en outre la formation dans le puits de descente de moyens de régulation qui sont aptes, lors de l'étape (b) de coulée, à créer une diminution de la pression d'écoulement du matériau en fusion à l'intérieur du puits, et qui consistent à réaliser une chambre de dépression en forme de bassin traversée par le puits sensiblement au-dessus du niveau de la partie supérieure de la cavité de moulage, lequel puits de descente débouche dans la partie inférieure du bassin de dépression par des orifices de sortie qui sont décalés par rapport à l'orifice ou aux orifices d'entrée du puits dans la partie supérieure du bassin.To this end, one of the objects of the invention is a molding process for the production of a part according to the so-called source casting technique, and consisting in:
  • (a) preparing a mold comprising at least one molding cavity of shape corresponding to that of the part to be produced, as well as at least one descent well which extends substantially vertically from a lower part or base of said cavity , with which it communicates, to an upper part of the mold where it opens; and
  • (b) pouring a liquid or molten material into the downpipe until at least the cavity is filled,
characterized in that the step (a) of preparation of the mold further comprises the formation in the downpipe of regulating means which are capable, during the step (b) of casting, of creating a reduction in the pressure flow of molten material inside the well, and which consists in providing a depression chamber in the form of a basin crossed by the well substantially above the level of the upper part of the molding cavity, which well descent opens into the lower part of the depression basin through outlet orifices which are offset from the orifice or inlet orifices of the well in the upper part of the basin.

Suivant une caractéristique de ce procédé, lors de l'étape (b), le bassin de dépression se remplit au fur et à mesure de la coulée, jusqu'à un niveau donné où l'alimentation de matière en fusion est interrompue, ce niveau étant déterminé pour que la quantité de matière en fusion contenue dans le bassin suffise à finir de remplir toutes les cavités du moule.According to a characteristic of this process, during step (b), the vacuum tank fills up as and when it is poured, up to a given level where the supply of molten material is interrupted, this level being determined so that the quantity of molten material contained in the basin is sufficient to finish filling all the cavities of the mold.

Suivant une autre caractéristique, l'étape (b) comprend en outre la détection du niveau donné dans le bassin de dépression, et la commande de l'interruption de ladite alimentation quand ce niveau est atteint.According to another characteristic, step (b) further comprises the detection of the level given in the depression basin, and the control of the interruption of said supply when this level is reached.

On précisera ici que, si le moule est alimenté par une poche de coulée ou analogue, équipée à sa partie inférieure d'une busette venant en contact avec le moule en regard du puits de descente, lors de l'étape de coulée (b), le niveau de matériau en fusion dans la poche est maintenu constant.It will be specified here that, if the mold is supplied by a ladle or the like, equipped at its lower part with a nozzle coming into contact with the mold opposite the downpipe, during the casting step (b) , the level of molten material in the pocket is kept constant.

La présente invention a également pour objet un moule pour la mise en oeuvre d'un procédé de coulée dite en source, du type comprenant au moins une cavité de moulage dont la forme correspond à celle d'une pièce à réaliser, et au moins un puits de descente qui s'étend sensiblement à la verticale depuis une partie inférieure ou base de ladite cavité avec laquelle il communique, jusqu'à une partie supérieure du moule où il débouche, caractérisé en ce que des moyens de régulation aptes à créer une diminution de la pression d'écoulement dans le puits de descente sont formés dans ce dernier et sont constitués par un bassin de dépression dans la partie inférieure duquel débouche le puits de descente par des orifices de sortie qui sont décalés par rapport à l'orifice ou aux orifices d'entrée du puits dans la partie supérieure du bassin.The present invention also relates to a mold for implementing a so-called source casting process, of the type comprising at least one molding cavity whose shape corresponds to that of a part to be produced, and at least one downspout which extends substantially vertically from a bottom or base of said cavity with which it communicates, up to an upper part of the mold where it opens, characterized in that regulating means capable of creating a reduction in the flow pressure in the downpipe are formed in the latter and are constituted by a depression basin in the lower part of which opens the descent well by outlet orifices which are offset relative to the orifice or the orifices of entry of the well in the upper part of the basin.

Le bassin de dépression possède une section qui est supérieure à celle du puits de descente et dans laquelle ce dernier débouche de part et d'autre.The depression basin has a section which is greater than that of the descent well and into which the latter opens on either side.

On précisera que le bassin de dépression est disposé à un niveau sensiblement au-dessus de celui de la partie supérieure de la cavité de moulage.It will be noted that the depression basin is arranged at a level substantially above that of the upper part of the molding cavity.

En outre, le moule se caractérise en ce qu'il comporte des moyens de détection aptes à déterminer si un niveau donné de matériau en fusion est atteint dans le bassin de dépression.In addition, the mold is characterized in that it comprises detection means capable of determining whether a given level of molten material is reached in the vacuum tank.

Mais d'autres avantages et caractéristiques de l'invention ressortiront mieux de la description détaillée d'un mode de réalisation donné uniquement à titre d'exemple, qui suit et se réfère aux dessins annexés, dans lesquels :

  • La figure 1 est une vue schématique en coupe d'un dispositif de fonderie équipé d'un moule pour coulée en source conforme à l'invention.
  • La figure 2 est une vue en coupe suivant la ligne II-II de la figure 1.
  • La figure 3 est une vue agrandie d'un détail de la figure 2, avec la quenouille en position d'obturation de la busette.
However, other advantages and characteristics of the invention will emerge more clearly from the detailed description of an embodiment given solely by way of example, which follows and refers to the appended drawings, in which:
  • Figure 1 is a schematic sectional view of a foundry device equipped with a mold for source casting according to the invention.
  • Figure 2 is a sectional view along line II-II of Figure 1.
  • Figure 3 is an enlarged view of a detail of Figure 2, with the stopper rod in the closed position of the nozzle.

En se reportant à la figure 1, on voit un dispositif de fonderie 10 pour la réalisation de pièces (non représentées) avec un matériau liquide ou en fusion, selon la technique de coulée dite "en source". Bien que l'exemple illustré se rapporte à la fonderie, l'invention peut également s'appliquer à d'autres techniques de moulage.Referring to Figure 1, there is a foundry device 10 for the production of parts (not shown) with a liquid or molten material, according to the so-called "source" casting technique. Although the example illustrated relates to foundry, the invention can also be applied to other molding techniques.

A la partie supérieure du dispositif 10, on a représenté une poche de coulée 20 en matériau réfractaire contenant un matériau ou métal en fusion 30 tel que par exemple une fonte à graphite sphéroïdal (fonte GS). La poche de coulée 20 comprend, au niveau d'une paroi 21 qui en constitue la partie inférieure ou fond, d'une part un conduit à matériau 22 et d'autre part une ouverture de coulée 23.At the upper part of the device 10, there is shown a ladle 20 made of refractory material containing a molten material or metal 30 such as for example a spheroidal graphite cast iron (cast iron GS). The ladle 20 comprises, at the level of a wall 21 which constitutes its lower part or bottom, on the one hand a material conduit 22 and on the other hand a pouring opening 23.

L'ouverture dans la paroi de fond 21 de la poche 20 est constituée par une busette 23. La référence 24 désigne un bouchon mobile ou quenouille, pouvant se déplacer de haut en bas suivant la direction de l'axe de la busette 23. Dans la position illustrée sur les figures 1 et 3, une partie immergée dans le métal 30 de la quenouille 24 est en contact avec l'ouverture de la busette 23 afin d'empêcher le métal 30 contenu dans la poche 20 de s'écouler au travers de la busette. Par contre, quand la quenouille 24 n'est pas en contact avec la busette 23 (figure 2), le métal 30 s'écoule hors de la poche 20 au travers de l'ouverture de coulée.The opening in the bottom wall 21 of the pocket 20 is constituted by a nozzle 23. The reference 24 designates a movable stopper or stopper, which can move up and down in the direction of the axis of the nozzle 23. In the position illustrated in FIGS. 1 and 3, a part immersed in the metal 30 of the stopper 24 is in contact with the opening of the nozzle 23 in order to prevent the metal 30 contained in the pocket 20 from flowing through of the nozzle. On the other hand, when the stopper 24 is not in contact with the nozzle 23 (FIG. 2), the metal 30 flows out of the pocket 20 through the casting opening.

Bien que l'exemple illustré comprenne une poche de coulée 20, tout autre équipement d'alimentation analogue tel qu'un four sous pression par exemple, peut également être utilisé.Although the example illustrated includes a ladle 20, any other similar feeding equipment such as a pressurized oven for example, can also be used.

Un moule 40 est disposé en dessous de la poche de coulée 20, et vient en contact avec la busette 23. Ce moule 40 qui peut être réalisé suivant toute technique conventionnelle, par exemple en sable, est disposé sur un mécanisme de maintien et de déplacement 50 de type connu, et comporte au moins une cavité de moulage 41 dont la forme correspond à celle d'une pièce à réaliser. Sur la figure 2, on a représenté quatre cavités de moulage 41 qui sont raccordées les unes aux autres, par leur partie inférieure ou base opposée à la poche 20, à l'aide d'un conduit horizontal de répartition 42 formé dans le moule.A mold 40 is arranged below the pocket of casting 20, and comes into contact with the nozzle 23. This mold 40 which can be produced according to any conventional technique, for example in sand, is placed on a holding and displacement mechanism 50 of known type, and comprises at least one cavity molding 41 whose shape corresponds to that of a part to be produced. In Figure 2, there is shown four molding cavities 41 which are connected to each other, by their lower part or base opposite the pocket 20, using a horizontal distribution duct 42 formed in the mold.

Un puits de descente désigné en 43 s'étend sensiblement à la verticale, depuis la base de la cavité où se trouve le conduit horizontal 42 avec lequel il communique, jusqu'à une partie supérieure du moule 40 où il débouche en regard de la busette 23. Evidemment, on peut aussi prévoir plusieurs puits de descente 43 dans chaque moule, par exemple un par cavité de moulage. A sa jonction avec le conduit de répartition 42, c'est-à-dire à son extrémité inférieure, le puits de descente 43 comporte de façon connue une chambre de freinage 43a qui permet de ralentir l'écoulement de métal 30 afin de ne pas endommager les cavités 41 du moule.A descent well designated at 43 extends substantially vertically, from the base of the cavity where the horizontal conduit 42 with which it communicates is located, to an upper part of the mold 40 where it opens facing the nozzle. 23. Obviously, it is also possible to provide several descent wells 43 in each mold, for example one per molding cavity. At its junction with the distribution duct 42, that is to say at its lower end, the downcomer 43 comprises in known manner a braking chamber 43a which makes it possible to slow down the flow of metal 30 so as not to damaging the mold cavities 41.

On remarque également sur la figure 1 un fil 33 fourré d'un additif tel qu'un alliage de silicium, qui permet d'effectuer à proximité de la busette 23 un traitement du métal en fusion 30, de façon à améliorer la microstructure de la pièce coulée une fois solidifiée après refroidissement.Note also in Figure 1 a wire 33 filled with an additive such as a silicon alloy, which allows to perform near the nozzle 23 a treatment of the molten metal 30, so as to improve the microstructure of the casting once solidified after cooling.

Conformément à la présente invention, des moyens de régulation 60 sont formés dans le puits de descente 43, afin de créer une diminution de la pression d'écoulement ou de coulée du métal 30 lors du remplissage des cavités de moulage 41.According to the present invention, regulating means 60 are formed in the downcomer 43, in order to create a reduction in the pressure metal flow or pouring 30 during filling of the mold cavities 41.

Comme visible sur les figures 2 et 3, ces moyens de régulation 60 sont notamment constitués par une chambre de dépression 61 en forme de bassin. La section de passage du métal dans la chambre de dépression 61 (autrement dit la section transversale à l'axe longitudinal du puits 43) est nettement supérieure à celle du puits. Le puits de descente débouche de part et d'autre de la chambre 61.As shown in Figures 2 and 3, these regulating means 60 are in particular constituted by a depression chamber 61 in the form of a basin. The metal passage section in the vacuum chamber 61 (in other words the cross section to the longitudinal axis of the well 43) is significantly greater than that of the well. The downpipe opens on either side of the chamber 61.

Plus précisément, le puits de descente 43 débouche dans la partie inférieure du bassin de dépression 61 par des orifices de sortie 63a et 63b. La partie supérieure, en regard avec la busette 23, du puits 43 débouche à la partie supérieure ou sommet de la chambre 61 par un orifice d'entrée 63c. On voit bien sur la figure 3 particulièrement que les orifices de sortie 63a, 63b sont décalés axialement -c'est-à-dire ne sont pas en regard- par rapport à l'orifice d'entrée 63c. Une telle disposition décalée des orifices d'entrée permet de freiner le flux de métal 30 provenant de la busette 23. Evidemment, le nombre d'orifices d'entrée et de sortie n'est pas limité à trois, tant que l'on prévoit un désalignement axial apte à casser l'écoulement dans la chambre 61.More specifically, the downcomer 43 opens into the lower part of the vacuum tank 61 through outlet orifices 63a and 63b. The upper part, facing the nozzle 23, of the well 43 opens to the upper part or top of the chamber 61 through an inlet port 63c. It can be seen clearly in FIG. 3 in particular that the outlet orifices 63a, 63b are offset axially -that is to say are not facing each other-with respect to the inlet orifice 63c. Such an offset arrangement of the inlet orifices makes it possible to brake the flow of metal 30 coming from the nozzle 23. Obviously, the number of inlet and outlet orifices is not limited to three, as long as provision is made an axial misalignment capable of breaking the flow in the chamber 61.

Par ailleurs, pour permettre un remplissage efficace des cavités de moulage 41, les moyens de régulation 60 sont formés dans le moule 40, de façon que la chambre de dépression 61 soit au-dessus du sommet des cavités 41. Comme on le voit bien sur la figure 2, les orifices de sortie 63a et 63b sont disposés dans le moule à un niveau A qui est supérieur au niveau B du sommet des cavités 41.Furthermore, to allow efficient filling of the mold cavities 41, the regulating means 60 are formed in the mold 40, so that the vacuum chamber 61 is above the top of the cavities 41. As can be seen on In FIG. 2, the outlet orifices 63a and 63b are arranged in the mold at a level A which is higher than the level B of the top of the cavities 41.

On voit sur les figures 1 et 2 qu'un conduit coudé 44 est formé dans le moule 40. Une extrémité de ce conduit débouche, similairement au puits 43, à la partie ou face supérieure du moule 40. L'autre extrémité du conduit 44 communique avec l'une des cavités de moulage 41, à un niveau C qui est sensiblement en dessous du niveau B correspondant au sommet des cavités 41.It can be seen in FIGS. 1 and 2 that a bent conduit 44 is formed in the mold 40. One end of this conduit opens, similarly to the well 43, at the upper part or face of the mold 40. The other end of the conduit 44 communicates with one of the molding cavities 41, at a level C which is substantially below the level B corresponding to the top of the cavities 41.

Un dispositif 70 de détection ou de visée par fibre optique par exemple, est disposé au droit du moule 40, en regard du conduit 44. Ainsi, quand le métal en fusion 30 atteint le niveau C dans les cavités 41, il pénètre dans le conduit 44 qui agit donc comme un conduit de regard. Quand le métal remplit la section horizontale du conduit de regard 44, un faisceau lumineux 74 émis par le dispositif 70 est réfléchi à nouveau vers ce dernier de façon à indiquer un remplissage des cavités 41 jusqu'au niveau C. Evidemment d'autres principes de détection peuvent être choisis.A device 70 for detecting or aiming by optical fiber for example, is placed in line with the mold 40, facing the conduit 44. Thus, when the molten metal 30 reaches level C in the cavities 41, it enters the conduit 44 which therefore acts as a viewing conduit. When the metal fills the horizontal section of the manhole 44, a light beam 74 emitted by the device 70 is reflected again towards the latter so as to indicate a filling of the cavities 41 up to level C. Obviously other principles of detection can be chosen.

On voit également sur la figure 1 un détecteur 80 qui permet de mesurer en permanence le niveau de métal 30 dans la poche 20. Ce détecteur 80 peut avantageusement comporter un émetteur de faisceau laser 81 et être relié à des moyens permettant de maintenir constant le niveau (désigné en D sur la figure 2) de métal 30 dans la poche de coulée.FIG. 1 also shows a detector 80 which makes it possible to permanently measure the level of metal 30 in the pocket 20. This detector 80 may advantageously include a laser beam emitter 81 and be connected to means making it possible to keep the level constant (designated in D in Figure 2) of metal 30 in the ladle.

Sur la figure 3, la section transversale de l'ouverture de la busette 23 est supérieure à celle du puits 43 dans lequel celle-ci débouche. La réduction de section entre la busette 23 et le puits 43 permet à des impuretés 25 de se fixer lors de la coulée du métal 30 sur les parois internes de la busette, sans provoquer d'importantes irrégularités de débit ou des à-coups dans l'écoulement.In FIG. 3, the cross section of the opening of the nozzle 23 is greater than that of the well 43 into which it opens. The reduction in cross-section between the nozzle 23 and the well 43 allows impurities 25 to be fixed during the pouring of the metal 30 on the internal walls of the nozzle, without causing significant irregularities in flow or jolts. in the flow.

Les particularités du procédé de coulée en source, qui consistent usuellement à (a) réaliser un moule avec au moins une cavité de moulage et au moins un puits de descente débouchant à la base d'une cavité, puis à (b) couler un matériau en fusion 30 dans le puits de descente 43, jusqu'au remplissage au moins de la cavité 41, vont maintenant être brièvement expliquées.The particularities of the source casting process, which usually consist in (a) making a mold with at least one molding cavity and at least one downhole opening at the base of a cavity, then in (b) casting a material molten 30 in the descent well 43, until at least filling of the cavity 41, will now be briefly explained.

Conformément à l'invention, l'étape (a) de préparation du moule 40 comprend en outre la formation dans le puits de descente 43 de moyens de régulation 60 aptes, lors de l'étape (b) de coulée, à créer une diminution de la pression d'écoulement du matériau en fusion 30 à l'intérieur du puits 43.According to the invention, step (a) of preparation of the mold 40 further comprises the formation in the downhole 43 of regulating means 60 capable, during step (b) of casting, to create a reduction the flow pressure of the molten material 30 inside the well 43.

Avec des moyens de régulation 60 tels que ceux décrits précédemment, lors de l'étape (b), le bassin de dépression 61 se remplit au fur et à mesure de la coulée jusqu'à un niveau donné qui est illustré en E sur la figure 2. Quand le métal en fusion 30 atteint ce niveau E, l'alimentation de matière en fusion 30 est interrompue en plaçant la quenouille 24 dans la position visible sur la figure 3.With regulating means 60 such as those described above, during step (b), the vacuum tank 61 fills as it is poured up to a given level which is illustrated at E in the figure. 2. When the molten metal 30 reaches this level E, the supply of molten material 30 is interrupted by placing the stopper 24 in the position visible in FIG. 3.

Afin d'obtenir un excellent remplissage des cavités 41, le niveau E est déterminé pour que la quantité de matière en fusion 30 contenue dans le bassin 61 ne remplisse pas entièrement celui-ci, mais suffise à finir de remplir toutes les cavités du moule 40. Par conséquent, l'étape (b) comprend en outre la détection du niveau donné E dans le bassin de dépression 61, et la commande de l'interruption de ladite alimentation quand ce niveau E est atteint. Dans l'exemple décrit ici, cette détection se fait indirectement par la détection du niveau C à l'aide du dispositif 70, les niveaux C et E étant déterminés pour que lorsque l'un est atteint, l'autre le soit aussi. Bien entendu, on ne sortirait pas du cadre de l'invention en utilisant d'autres moyens pour détecter le niveau E. On peut ainsi éviter les coups de bélier qui survenaient dans l'art antérieur lorsque le moule 40 était plein, et s'assurer que la quantité de métal en fusion 30 contenue dans le bassin est juste suffisante pour finir de remplir les cavités.In order to obtain an excellent filling of the cavities 41, the level E is determined so that the quantity of molten material 30 contained in the basin 61 does not completely fill the latter, but is sufficient to finish filling all the cavities of the mold 40 Consequently, step (b) further comprises the detection of the given level E in the depression basin 61, and the control of the interruption of said supply when this level E is reached. In the example described here, this detection is done indirectly by the detection of level C using the device 70, the levels C and E being determined so that when one is reached, the other is also reached. Of course, it would not go beyond the scope of the invention by using other means to detect the level E. It is thus possible to avoid the water hammer which occurred in the prior art when the mold 40 was full, and s' ensure that the quantity of molten metal 30 contained in the basin is just sufficient to finish filling the cavities.

On comprend que grâce aux caractéristiques de l'invention, et notamment à la présence d'une surface libre dans le bassin de dépression 61, on peut éviter les surpressions de métal dues à la hauteur métallostatique dans la poche de coulée. De plus, en coupant l'alimentation en métal grâce à la visée effectuée par le dispositif 70, on peut remplir calmement à la fin des cavités 41 (c'est-à-dire l'espace entre le niveau C et le sommet B de ces cavités) ce qui permet de réduire la mise au mille.It is understood that thanks to the characteristics of the invention, and in particular to the presence of a free surface in the vacuum tank 61, it is possible to avoid metal overpressures due to the metallostatic height in the ladle. In addition, by cutting off the metal supply thanks to the sighting carried out by the device 70, it is possible to calmly fill at the end of the cavities 41 (that is to say the space between the level C and the apex B of these cavities) which reduces the mileage.

On obtient conformément à l'invention une excellente maîtrise du débit permettant des temps de remplissage constants et une précision de dosage importante.In accordance with the invention, excellent control of the flow rate is obtained, allowing constant filling times and high dosing precision.

Claims (8)

  1. Method of moulding for making a part according to the so-called bottom casting process and consisting :
    (a) in preparing a mould (40) comprising at least one moulding cavity (41) with a shape corresponding to that of the part to be made as well as at least one down-gate sprue (43) which extends substantially in the vertical direction from a lower portion or base of the said cavity (41) with which it communicates to an upper portion of the mould (40) where it opens out; and
    (b) in pouring a liquid or molten material (30) into the down-gate sprue (43) until the filling up of at least the cavity (41),
    characterized in that the step (a) of preparation of the mould (40) further comprises the formation, in the down-gate sprue (43), of regulation means (60) which are adapted during of the pouring step (b) to create a decrease in the pressure of flow of the molten material (30) inside of the sprue (43) and which consist in providing a basin-shaped underpressure chamber (61) through which extends the sprue (43) substantially above the level of the upper portion of the moulding cavity (41), which down-gate sprue (43) opens into the lower portion of the underpressure basin (61) through outlet apertures (63a, 63b) which are offset with respect to the inlet aperture or apertures (63c) of the sprue (43) in the upper portion of the basin (61).
  2. Method according to claim 1, characterized in that during the step (b), the underpressure basin (61) is filling up in proportion as the casting proceeds up to a given level (E) where the feed with molten material is discontinued, this level (e) being determined in order that the amount of molten material (30) contained in the basin (61) be sufficient for finishing to fill up all the cavities (41) of the mould (40).
  3. Method according to claim 1 or 2, characterized in that the step (b) further comprises the detection of the given level (E) in the underpressure basin (61) and the control of the discontinuance of the said feed when this level (E) is reached.
  4. Method according to one of claims 1 to 3, according to which the mould is fed by a pouring ladle or the like fitted at its lower portion with a nozzle (23) coming in contact with the mould in front of the down-gate sprue (43), characterized in that during the step (b), the level of the molten material (30) in the ladle is kept constant.
  5. Mould for carrying out a method of so-called bottom casting, of the type comprising at least one moulding cavity the shape of which corresponds to that of a part to be made and at least one down-gate sprue (43) which extends substantially in the vertical direction from a lower portion or base of the said cavity (41) with which it communicates up to an upper portion of the mould (40) where it opens out, characterized in that regulation means (60) adapted to create a decrease in the pressure of flow in the down-gate sprue (43) are formed in the latter and are constituted by an underpressure basin (61) into the lower portion of which opens the down-gate sprue (43) through outlet apertures (63a, 63b) which are offset with respect to the inlet aperture or apertures (63c) of the sprue (43) in the upper portion of the basin (61).
  6. Mould according to claim 5, characterized in that the underpressure basin (61) has a section which is greater than that of the sprue (43) and into which the latter opens on either side.
  7. Mould according to claim 6, characterized in that the underpressure basin (61) is disposed at a level (A) substantially above the upper portion (B) of the moulding cavity (41).
  8. Mould according to claim 6 or 7, characterized in that it comprises detection means (70, 44) adapted to determine whether a given level (E) of liquid or molten material (30) poured into the sprue is reached in the moulding cavity (41).
EP19920402256 1991-08-09 1992-08-07 Method for bottom pouring with controlled mould filling and mould Expired - Lifetime EP0528723B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9110190 1991-08-09
FR9110190A FR2680124B1 (en) 1991-08-09 1991-08-09 SOURCE PROCESS WITH REGULATED AND MOLDED FILLING FOR THE IMPLEMENTATION OF THIS PROCESS.

Publications (2)

Publication Number Publication Date
EP0528723A1 EP0528723A1 (en) 1993-02-24
EP0528723B1 true EP0528723B1 (en) 1996-09-25

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EP19920402256 Expired - Lifetime EP0528723B1 (en) 1991-08-09 1992-08-07 Method for bottom pouring with controlled mould filling and mould

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EP (1) EP0528723B1 (en)
DE (1) DE69214067T2 (en)
FR (1) FR2680124B1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2832357B1 (en) * 2001-11-21 2004-02-27 Peugeot Citroen Automobiles Sa DEVICE FOR TRANSMITTING POWER TO AT LEAST TWO EPICYCLOIDAL TRAINS

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2216040A1 (en) * 1973-02-01 1974-08-30 Sigma Lutin Casting system - for vertically sepd moulds
GB2016327B (en) * 1978-02-10 1982-04-21 Rolls Royce Metal pouring apparatus
GB1582519A (en) * 1978-05-24 1981-01-07 British Steel Corp Teeming into ingots

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FR2680124A1 (en) 1993-02-12
DE69214067T2 (en) 1997-05-15
EP0528723A1 (en) 1993-02-24
DE69214067D1 (en) 1996-10-31
FR2680124B1 (en) 1993-10-15

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