EP0463910A1 - Process and device for feeding a sand mould with liquid metal using low pressure - Google Patents

Process and device for feeding a sand mould with liquid metal using low pressure Download PDF

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Publication number
EP0463910A1
EP0463910A1 EP91401543A EP91401543A EP0463910A1 EP 0463910 A1 EP0463910 A1 EP 0463910A1 EP 91401543 A EP91401543 A EP 91401543A EP 91401543 A EP91401543 A EP 91401543A EP 0463910 A1 EP0463910 A1 EP 0463910A1
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EP
European Patent Office
Prior art keywords
mold
well
stage
attacks
casting
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Granted
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EP91401543A
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German (de)
French (fr)
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EP0463910B1 (en
Inventor
Pascal Sourlier
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Pont a Mousson SA
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Pont a Mousson SA
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/20—Stack moulds, i.e. arrangement of multiple moulds or flasks
    • 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
    • B22D18/00—Pressure casting; Vacuum casting
    • B22D18/04—Low pressure casting, i.e. making use of pressures up to a few bars to fill the mould

Definitions

  • the present invention relates to the casting of metal under low pressure in a blind sand mold. It relates firstly to a process for feeding several imprints of the same stage of a mold in blind sand, in metal casting under low pressure, the feeding being carried out via a pouring well, at least one intermediate channel and attacks.
  • the low pressure casting technique (see for example FR-A-2 295 808, 2 367 566 and 2 556 996 in the name of the Applicant) is particularly advantageous, compared to gravity casting, for producing metal parts with thin wall and / or of complex shape and / or of large dimensions. Indeed, the pressure exerted by the metal, which results from the injection of a gas into a sealed pocket containing the liquid metal, can be controlled at will so as to push the metal into all the recesses of the imprints.
  • the invention aims to remedy these drawbacks.
  • the method according to the invention is characterized in that only attacks leading to a single imprint are assigned to each channel.
  • the invention also relates to a blind sand mold intended for the implementation of such a method.
  • This mold of the type comprising a pouring well and at least one stage where several imprints are provided, these imprints being supplied via attacks connected to the casting well by at least one intermediate channel, is characterized in that all the attacks fed by the same intermediate channel lead into the same footprint.
  • the invention also relates to an installation for casting metal under low pressure in a blind sand mold, of the type comprising a pouring ladle from which a feed tube opens upwards, a source of pressurized gas connected in the pocket, at least one blind sand mold comprising a pouring well open downwards and at least one stage where several imprints are provided, these imprints being supplied via attacks connected to the casting well by at least one intermediate channel, and means for applying the base of the tapping well to the opening of the supply tube, characterized in that the mold is as defined above.
  • the installation shown in Fig. 1 comprises an enclosure 1 forming a pocket or reserve of liquid metal 2, a frame 3 for mold support and a sand mold 4. It is applied to low pressure casting of cast iron (gray cast iron or spheroidal graphite cast iron) in the mold 4. Apart from the internal configuration of this mold, the installation is identical to that described in the aforementioned FR-A-2 295 808.
  • the fixed pocket 1 comprises an upper cover 5 fixed in leaktight manner to its side walls and locked by appropriate means (not shown).
  • a pouring nozzle 6 passes through an orifice 7 formed in the cover 5.
  • This nozzle 6 comprises a tubular lower part 8 whose outside diameter corresponds to the diameter of the orifice 7 and an upper part 9, of generally frustoconical shape, which s' presses tightly on the periphery of the orifice 7 by its large flat base 10.
  • a seal 11 formed by an asbestos bead is housed in a groove formed in the base 10 of the nozzle.
  • the nozzle 6 is traversed by a conduit or supply tube 12 made of refractory material dipping into the cast iron up to the vicinity of the bottom of the pocket 1; the upper part of the duct 12 opens out at the center of the nozzle 6, at the level of the planar upper face of the latter.
  • the bag 1 is connected to a source 13 of gas under pressure by a conduit 14, the communication of the bag 1 with the pressure source 13 or with the atmosphere being effected by a suitable device 15 outside the bag.
  • a pressure gauge 16 makes it possible to monitor the pressure prevailing inside the pocket during pouring.
  • the frame 3 comprises posts 17 provided at their base with wheels 18 carried by two rails 19.
  • the posts 17 are joined at their upper end by a ceiling 20 carrying a jack 21 directed downwards and whose piston rod 22 carries, articulated at its lower end, a support plate 23.
  • the posts 17 also each carry a flange 24 on which a helical spring 25 rests.
  • a horizontal support plate 26 can slide vertically along a part of the posts 17 situated above the flanges 24; this plate 26 is in constant abutment on the upper end of the springs 25 and is urged by them upwards. When no downward pressure is applied to the plate 26, the latter is at a level higher than that of the upper face of the nozzle 6.
  • a circular opening 27, of sufficient diameter to allow the nozzle 6 to pass is provided in the plate 26.
  • the mold 4 is a solid multi-stage blind mold, for example with three stages, as shown in FIG. 2. It is made of sand and includes a vertical pouring well 28, of circular section roughly equal to that of the supply tube 12. This well is open at its base, which has a housing 29 having a tapered flared shape combined with that of nozzle 6. It extends up to a certain distance from the upper end face of the mold.
  • each stage is identical, and the structure of each stage appears in FIG. 3. From the tapping well 28 there are four intermediate channels horizontally, two of which 30A extend in a first direction, parallel to each other, and the other two 30B extend in the opposite direction and are also parallel l to each other. Each channel 30B extends in the extension of a channel 30A.
  • the stage also comprises two indentations 31 of elongated shape, identical and arranged head to tail, that is to say symmetrically with respect to the vertical axis X-X of the tapping well.
  • Each footprint which extends on either side of the well 28, is fed by three attacks. In the example shown, there is for each fingerprint an attack 32A on one side of the well and two attacks 32B on the other side.
  • Attack 32A connects the imprint to a channel 30A, and the two attacks 32B connect it to channel 30B situated in the extension thereof.
  • Each channel 30A or 30B only connects the pouring well to a single footprint 31.
  • the attacks which feed one of the footprints, being arranged as required metal footprint are located at variable distances from the XX axis and have no reason to be opposite those that feed the other footprint.
  • Channels 30A and 30B have a relatively small section, since each of them feeds only a small number of attacks. More precisely, the sum of the areas of the sections of the intermediate channels 30A, 30B of a stage is much less than the area of the section of the well 28, for example less at 10% of this area. If the channels are of variable section, it is their input section which fulfills this condition.
  • the operation of the installation is as follows: the frame 3 being distant from the pocket 1, an appropriate refractory seal 33 is applied to the bottom of the housing 29 of the mold 4.
  • the mold 4, containing in each cavity a non-core shown, is placed on the plate 26 and centered on the opening 27 thereof, then the frame 3 is brought on the rails 19 above the pocket 1 of liquid iron so that the nozzle 6 is opposite of the housing 29 of the mold.
  • the jack 21 is then extended so as to lower, by means of the plate 23, the mold 4 and its support 26 against the force of the springs 25. This operation tightens the seal 33 between the bottom of the housing 29 and the nozzle 6 and ensures the sealed connection of the pouring well to the supply tube.
  • the bag 1 is then connected to the pressure source 13 by operating the device 15.
  • the pressure acting on the free surface of the cast iron makes it rise in the tube 12.
  • the cast iron fills the well 28 of the mold, the channels 30A and 30B and the imprints 31.
  • the pressure is maintained for a time determined according to the dimensions and the shapes of the parts to be obtained.
  • the well 28 plays during this time the role of reserve or counterweight by providing the footprints with the additional liquid iron intended to compensate for the withdrawals.
  • the attacks and the intermediate channels solidify, the gas pressure is brought back to atmospheric pressure in the pocket 1, by operation of the device 15, and the liquid iron being in the well 28 and in the tube 12 goes back down in the pocket 1 by evacuating these two ducts.
  • the liquid metal rises rapidly in the well 28, ensuring a metallostatic height sufficient to supply each imprint individually by its pair of channels 30A and 30B.
  • the narrowness of the intermediate channels limits the flow of metal flowing therein, which leads on the one hand to a minimal displacement of metal at each pouring, and on the other hand to a better controlled and quieter filling prints. This ultimately results in an improvement in the health of the castings.

Abstract

The mould (4) comprises, at each stage, several impressions (31) fed via runners (32A 32B) connected to the casting pool (28) via at least one intermediate channel (30A, 30B). All the runners fed by one and the same intermediate channel emerge in the same impression. Application to the moulding of thin-wall castings having an elongated shape. <IMAGE>

Description

La présente invention est relative à la coulée de métal sous basse pression en moule en sable borgne. Elle concerne en premier lieu un procédé pour alimenter plusieurs empreintes d'un même étage d'un moule en sable borgne, en coulée de métal sous basse pression, l'alimentation s'effectuant via un puits de coulée, au moins un canal intermédiaire et des attaques.The present invention relates to the casting of metal under low pressure in a blind sand mold. It relates firstly to a process for feeding several imprints of the same stage of a mold in blind sand, in metal casting under low pressure, the feeding being carried out via a pouring well, at least one intermediate channel and attacks.

La technique de coulée sous basse pression (voir par exemple les FR-A-2 295 808, 2 367 566 et 2 556 996 au nom de la Demanderesse) est particulièrement avantageuse, par rapport à la coulée gravitaire, pour réaliser des pièces métalliques à paroi mince et/ou de forme complexe et/ou de grandes dimensions. En effet, la pression exercée par le métal, qui résulte de l'injection d'un gaz dans une poche étanche contenant le métal liquide, peut être commandée à volonté de façon à pousser le métal dans tous les recoins des empreintes.The low pressure casting technique (see for example FR-A-2 295 808, 2 367 566 and 2 556 996 in the name of the Applicant) is particularly advantageous, compared to gravity casting, for producing metal parts with thin wall and / or of complex shape and / or of large dimensions. Indeed, the pressure exerted by the metal, which results from the injection of a gas into a sealed pocket containing the liquid metal, can be controlled at will so as to push the metal into all the recesses of the imprints.

Dans la technique classique, à chaque étage du moule, un canal intermédiaire unique, ou deux canaux intermédiaires diamétralement opposés, relient le puits de coulée à l'ensemble des attaques de l'étage.In the conventional technique, on each stage of the mold, a single intermediate channel, or two diametrically opposite intermediate channels, connect the casting well to all of the attacks on the stage.

Cette manière de faire présente les inconvénients suivants :

  • (1) Lorsque les pièces à couler ont une forme allongée complexe et sont disposées tête-bêche à chaque étage du moule, les attaques ne sont pas disposées symétriquement par rapport au canal de coulée les alimentant et le nombre d'attaques, pour un canal donné, peut varier d'une empreinte à l'autre à un même étage. Le remplissage des deux empreintes n'est donc pas équilibré.
  • (2) Le canal unique a une grande section, favorable à la création de turbulences dans le flot de métal et, par suite, à l'érosion du sable et à l'occlusion de bulles d'air, au détriment de la santé des pièces obtenues ; de plus, un tel canal consomme beaucoup de métal pour son remplissage.
  • (3) Dans le cas d'un moule à plusieurs étages, à cause de la grande section du canal intermédiaire, il n'est par possible de faire monter rapidement le métal jusqu'au sommet du puits de coulée, et le remplissage s'effectue en fait par étage, ce qui ne permet pas de bénéficier de tous les avantages de la coulée basse pression.
  • (4) Lorsque la pression est relâchée, après solidification des attaques qui forment obturateurs (voir le FR-A-2 295 808 précité), le metal contenu dans le canal intermédiaire, représentant un volume relativement grand qui s'est notablement refroidi, retourne dans la poche de coulée. A la coulée suivante, c'est du métal moins chaud qui monte en premier dans le puits de coulée, ce qui nuit à la qualité de certaines pièces moulées. Pour la même raison, un déplacement de métal excessif est necessaire à chaque coulée.
This way of doing things has the following drawbacks:
  • (1) When the parts to be cast have a complex elongated shape and are arranged head to tail on each stage of the mold, the attacks are not arranged symmetrically with respect to the casting channel supplying them and the number of attacks, for a channel given, may vary from one footprint to another on the same floor. The filling of the two imprints is therefore not balanced.
  • (2) The single channel has a large section, favorable to the creation of turbulence in the metal flow and, consequently, to the erosion of the sand and the occlusion of air bubbles, to the detriment of the health of the parts obtained; moreover, such a channel consumes a lot of metal for its filling.
  • (3) In the case of a multistage mold, because of the large cross-section of the intermediate channel, it is not possible to rapidly raise the metal to the top of the casting well, and the filling is actually performs by stage, which does not allow to benefit from all the advantages of low pressure casting.
  • (4) When the pressure is released, after solidification of the attacks which form shutters (see FR-A-2 295 808 cited above), the metal contained in the intermediate channel, representing a relatively large volume which has notably cooled, returns in the ladle. At the next casting, less warm metal rises first in the casting well, which affects the quality of some molded parts. For the same reason, an excessive metal displacement is necessary for each casting.

L'invention a pour but de remédier à ces inconvénients. A cet effet, le procédé suivant l'invention est caractérisé en ce qu'on affecte à chaque canal uniquement des attaques débouchant dans une seule empreinte.The invention aims to remedy these drawbacks. To this end, the method according to the invention is characterized in that only attacks leading to a single imprint are assigned to each channel.

Suivant d'autres caracteristiques :

  • on envoie dans le tube d'amenée un débit de métal liquide adapté pour provoquer une montée de ce métal au-dessus de tous les canaux intermédiaires;
  • on maintient la pression d'alimentation du moule jusqu'à solidification de tous les canaux intermédiaires, puis on relâche cette pression.
According to other characteristics:
  • a flow of liquid metal adapted to cause this metal to rise above all of the intermediate channels is sent into the supply tube;
  • the mold supply pressure is maintained until all the channels solidify intermediaries, then release that pressure.

L'invention a également pour objet un moule en sable borgne destiné à la mise en oeuvre d'un tel procédé. Ce moule, du type comprenant un puits de coulée et au moins un étage où sont prévues plusieurs empreintes, ces empreintes étant alimentées via des attaques reliées au puits de coulée par au moins un canal intermediaire, est caracterisé en ce que toutes les attaques alimentées par un même canal intermédiaire débouchent dans la même empreinte.The invention also relates to a blind sand mold intended for the implementation of such a method. This mold, of the type comprising a pouring well and at least one stage where several imprints are provided, these imprints being supplied via attacks connected to the casting well by at least one intermediate channel, is characterized in that all the attacks fed by the same intermediate channel lead into the same footprint.

Suivant d'autres caractéristiques :

  • chaque empreinte est alimentée par deux canaux intermédiaires s'étendant de part et d'autre du puits de coulée ;
  • la somme des aires des sections d'entrée des canaux intermédiaires d'un étage est nettement inférieure à l'aire de la section du puits de coulée ;
  • le moule est multiétages.
According to other characteristics:
  • each footprint is fed by two intermediate channels extending on either side of the tapping well;
  • the sum of the areas of the inlet sections of the intermediate canals of a stage is much less than the area of the section of the taphole;
  • the mold is multi-stage.

L'invention a encore pour objet une installation de coulée de metal sous basse pression en moule en sable borgne, du type comprenant une poche de coulée d'où part un tube d'amenée ouvert vers le haut, une source de gaz sous pression reliée à la poche, au moins un moule en sable borgne comprenant un puits de coulée ouvert vers le bas et au moins un étage où sont prévues plusieurs empreintes, ces empreintes étant alimentées via des attaques reliées au puits de coulée par au moins un canal intermédiaire, et des moyens pour appliquer la base du puits de coulée sur l'ouverture du tube d'amenée, caractérisée en ce que le moule est tel que défini ci-dessus.The invention also relates to an installation for casting metal under low pressure in a blind sand mold, of the type comprising a pouring ladle from which a feed tube opens upwards, a source of pressurized gas connected in the pocket, at least one blind sand mold comprising a pouring well open downwards and at least one stage where several imprints are provided, these imprints being supplied via attacks connected to the casting well by at least one intermediate channel, and means for applying the base of the tapping well to the opening of the supply tube, characterized in that the mold is as defined above.

Un exemple non limitatif de mise en oeuvre de l'invention va maintenant être décrit en regard des dessins annexés sur lesquels :

  • la Fig. 1 représente schématiquement, en coupe verticale, une installation de coulée conforme à l'invention ;
  • la Fig. 2 représente un moule utilisé dans cette installation, en coupe suivant la ligne II-II de la Fig. 3 ; et
  • la Fig. 3 est une vue prise en coupe suivant la ligne III-III de la Fig. 2.
A nonlimiting example of implementation of the invention will now be described with reference to the appended drawings in which:
  • Fig. 1 schematically represents, in vertical section, a casting installation according to the invention;
  • Fig. 2 shows a mold used in this installation, in section along line II-II of FIG. 3; and
  • Fig. 3 is a view taken in section along line III-III of FIG. 2.

L'installation présentée à la Fig. 1 comporte une enceinte 1 formant une poche ou réserve de métal liquide 2, un bâti 3 de support de moule et un moule en sable 4. Elle est appliquée à la coulée sous basse pression de fonte (fonte grise ou fonte à graphite sphéroïdal) dans le moule 4. A part la configuration interne de ce moule, l'installation est identique à celle décrite dans le FR-A-2 295 808 précité.The installation shown in Fig. 1 comprises an enclosure 1 forming a pocket or reserve of liquid metal 2, a frame 3 for mold support and a sand mold 4. It is applied to low pressure casting of cast iron (gray cast iron or spheroidal graphite cast iron) in the mold 4. Apart from the internal configuration of this mold, the installation is identical to that described in the aforementioned FR-A-2 295 808.

La poche 1, fixe, comporte un couvercle supérieur 5 fixé de façon étanche à ses parois latérales et verrouillé par des moyens appropriés (non représentér). Une buse de coulée 6 traverse un orifice 7 ménagé dans le couvercle 5. Cette buse 6 comporte une partie inférieure tubulaire 8 dont le diamètre extérieur correspond au diamètre de l'orifice 7 et une partie supérieure 9, de forme générale tronconique, qui s'appuie de façon étanche sur la périphérie de l'orifice 7 par sa grande base plane 10. Une garniture d'étanchéité 11 constituée par un cordon d'amiante est logée dans une gorge ménagée dans la base 10 de la buse. La buse 6 est traversée par un conduit ou tube d'amenée 12 en matériau réfractaire plongeant dans la fonte jusqu'au voisinage du fond de la poche 1 ; la partie supérieure du conduit 12 débouche au centre de la buse 6, au niveau de la face supérieure plane de celle-ci.The fixed pocket 1 comprises an upper cover 5 fixed in leaktight manner to its side walls and locked by appropriate means (not shown). A pouring nozzle 6 passes through an orifice 7 formed in the cover 5. This nozzle 6 comprises a tubular lower part 8 whose outside diameter corresponds to the diameter of the orifice 7 and an upper part 9, of generally frustoconical shape, which s' presses tightly on the periphery of the orifice 7 by its large flat base 10. A seal 11 formed by an asbestos bead is housed in a groove formed in the base 10 of the nozzle. The nozzle 6 is traversed by a conduit or supply tube 12 made of refractory material dipping into the cast iron up to the vicinity of the bottom of the pocket 1; the upper part of the duct 12 opens out at the center of the nozzle 6, at the level of the planar upper face of the latter.

La poche 1 est reliée à une source 13 de gaz sous pression par un conduit 14, la mise en communication de la poche 1 avec la source de pression 13 ou avec l'atmosphère s'effectuant par un dispositif approprié 15 extérieur à la poche. Un manomètre 16 permet de surveiller la pression régnant à l'intérieur de la poche lors de la coulée.The bag 1 is connected to a source 13 of gas under pressure by a conduit 14, the communication of the bag 1 with the pressure source 13 or with the atmosphere being effected by a suitable device 15 outside the bag. A pressure gauge 16 makes it possible to monitor the pressure prevailing inside the pocket during pouring.

Le bâti 3 comprend des poteaux 17 munis à leur base de roues 18 portées par deux rails 19.The frame 3 comprises posts 17 provided at their base with wheels 18 carried by two rails 19.

Les poteaux 17 sont réunir à leur extrémité supérieure par un plafond 20 portant un verin 21 dirigé vers le bas et dont la tige de piston 22 porte, articulée à son extrémité inférieure, une plaque d'appui 23.The posts 17 are joined at their upper end by a ceiling 20 carrying a jack 21 directed downwards and whose piston rod 22 carries, articulated at its lower end, a support plate 23.

Les poteaux 17 portent également chacun une collerette 24 sur laquelle s'appuie un ressort hélicoïdal 25. Une plaque de support 26 horizontale peut coulisser verticalement le long d'une partie des poteaux 17 située au-dessus des collerettes 24 ; cette plaque 26 est en appui constant sur l'extrémité supérieure des ressorts 25 et est sollicitée par ceux-ci vers le haut. Lorsqu'aucune pression vers le bas n'est appliquée à la plaque 26, celle-ci se trouve à un niveau supérieur à celui de la face supérieure de la buse 6. Une ouverture circulaire 27, de diamètre suffisant pour laisser passer la buse 6, est ménagée dans la plaque 26.The posts 17 also each carry a flange 24 on which a helical spring 25 rests. A horizontal support plate 26 can slide vertically along a part of the posts 17 situated above the flanges 24; this plate 26 is in constant abutment on the upper end of the springs 25 and is urged by them upwards. When no downward pressure is applied to the plate 26, the latter is at a level higher than that of the upper face of the nozzle 6. A circular opening 27, of sufficient diameter to allow the nozzle 6 to pass , is provided in the plate 26.

Le moule 4 est un moule borgne massif multiétage, par exemple à trois étages, comme représenté sur la Fig. 2. Il est réalisé en sable et comprend un puits de coulée 28 vertical, de section circulaire à peu près égale à celle du tube d'amenée 12. Ce puits est ouvert à sa hase, qui présente un logement 29 ayant une forme évasée tronconique conjuguée de celle de la buse 6. Il s'étend jusqu'à une certaine distance de la face d'extrémité supérieure du moule.The mold 4 is a solid multi-stage blind mold, for example with three stages, as shown in FIG. 2. It is made of sand and includes a vertical pouring well 28, of circular section roughly equal to that of the supply tube 12. This well is open at its base, which has a housing 29 having a tapered flared shape combined with that of nozzle 6. It extends up to a certain distance from the upper end face of the mold.

Les trois étages sont identiques, et la structure de chaque étage apparaît sur la Fig. 3. Du puits de coulée 28 partent horizontalement quatre canaux intermédiaires, dont deux 30A s'étendent dans une première direction, parallèlement l'un à l'autre, et les deux autres 30B s'étendent dans la direction opposée et sont également parallèles l'un à l'autre. Chaque canal 30B s'étend dans le prolongement d'un canal 30A. L'étage comprend encore deux empreintes 31 de forme allongée, identiques et disposées tête-bêche, c'est-à-dire symétriquement par rapport à l'axe vertical X-X du puits de coulée. Chaque empreinte, qui s'étend de part et d'autre du puits 28, est alimentée par trois attaques. Dans l'exemple représenté, il y a pour chaque empreinte une attaque 32A d'un côté du puits et deux attaques 32B de l'autre côté. L'attaque 32A relie l'empreinte à un canal 30A, et les deux attaques 32B la relient au canal 30B situé dans le prolongement de celui-ci. Chaque canal 30A ou 30B ne relie le puits de coulée qu'à une seule empreinte 31. En considérant l'ensemble de l'étage (Fig. 3), les attaques qui alimentent l'une des empreintes, étant disposées en fonction des nécessités d'alimentation de l'empreinte en métal, sont situées à des distances variables de l'axe X-X et n'ont pas de raison de se trouver en face de celles qui alimentent l'autre empreinte.The three stages are identical, and the structure of each stage appears in FIG. 3. From the tapping well 28 there are four intermediate channels horizontally, two of which 30A extend in a first direction, parallel to each other, and the other two 30B extend in the opposite direction and are also parallel l to each other. Each channel 30B extends in the extension of a channel 30A. The stage also comprises two indentations 31 of elongated shape, identical and arranged head to tail, that is to say symmetrically with respect to the vertical axis X-X of the tapping well. Each footprint, which extends on either side of the well 28, is fed by three attacks. In the example shown, there is for each fingerprint an attack 32A on one side of the well and two attacks 32B on the other side. Attack 32A connects the imprint to a channel 30A, and the two attacks 32B connect it to channel 30B situated in the extension thereof. Each channel 30A or 30B only connects the pouring well to a single footprint 31. Considering the entire stage (Fig. 3), the attacks which feed one of the footprints, being arranged as required metal footprint, are located at variable distances from the XX axis and have no reason to be opposite those that feed the other footprint.

Les canaux 30A et 30B ont une section relativement petite, puisque chacun d'eux n'alimente qu'un petit nombre d'attaques. Plus précisément, la somme des aires des sections des canaux intermédiaires 30A, 30B d'un étage est nettement inférieure à l'aire de la section du puits de coulée 28, par exemple inférieure à 10 % de cette aire. Si les canaux sont à section variable, c'est leur section d'entrée qui remplit cette condition.Channels 30A and 30B have a relatively small section, since each of them feeds only a small number of attacks. More precisely, the sum of the areas of the sections of the intermediate channels 30A, 30B of a stage is much less than the area of the section of the well 28, for example less at 10% of this area. If the channels are of variable section, it is their input section which fulfills this condition.

Le fonctionnement de l'installation est le suivant : le bâti 3 étant éloigné de la poche 1, un joint d'étanchéité réfractaire approprié 33 est appliqué au fond du logement 29 du moule 4. Le moule 4, contenant dans chaque empreinte un noyau non représenté, est placé sur la plaque 26 et centré sur l'ouverture 27 de celle-ci, puis le bâti 3 est amené sur les rails 19 au-dessus de la poche 1 de fonte liquide de façon que la buse 6 se trouve en regard du logement 29 du moule. Le vérin 21 est alors mis en extension de façon à abaisser, par l'intermédiaire de la plaque 23, le moule 4 et son support 26 à l'encontre de la force des ressorts 25. Cette opération serre le joint 33 entre le fond du logement 29 et la buse 6 et assure la liaison étanche du puits de coulée au tube d'amenée.The operation of the installation is as follows: the frame 3 being distant from the pocket 1, an appropriate refractory seal 33 is applied to the bottom of the housing 29 of the mold 4. The mold 4, containing in each cavity a non-core shown, is placed on the plate 26 and centered on the opening 27 thereof, then the frame 3 is brought on the rails 19 above the pocket 1 of liquid iron so that the nozzle 6 is opposite of the housing 29 of the mold. The jack 21 is then extended so as to lower, by means of the plate 23, the mold 4 and its support 26 against the force of the springs 25. This operation tightens the seal 33 between the bottom of the housing 29 and the nozzle 6 and ensures the sealed connection of the pouring well to the supply tube.

La poche 1 est ensuite reliée à la source de pression 13 par manoeuvre du dispositif 15. La pression agissant sur la surface libre de la fonte fait monter celle-ci dans le tube 12. La fonte remplit le puits 28 du moule, les canaux 30A et 30B et les empreintes 31. La pression est maintenue pendant un temps déterminé en fonction des dimensions et des formes des pièces à obtenir. Le puits 28 joue pendant ce temps le rôle de réserve ou de masselotte en apportant aux empreintes la fonte liquide supplémentaire destinée à compenser les retraits. Puis les attaques et les canaux intermédiaires se solidifient, la pression de gaz est ramenée à la pression atmosphérique dans la poche 1, par manoeuvre du dispositif 15, et la fonte liquide se trouvant dans le puits 28 et dans le tube 12 redescend dans la poche 1 en évacuant ces deux conduits.The bag 1 is then connected to the pressure source 13 by operating the device 15. The pressure acting on the free surface of the cast iron makes it rise in the tube 12. The cast iron fills the well 28 of the mold, the channels 30A and 30B and the imprints 31. The pressure is maintained for a time determined according to the dimensions and the shapes of the parts to be obtained. The well 28 plays during this time the role of reserve or counterweight by providing the footprints with the additional liquid iron intended to compensate for the withdrawals. Then the attacks and the intermediate channels solidify, the gas pressure is brought back to atmospheric pressure in the pocket 1, by operation of the device 15, and the liquid iron being in the well 28 and in the tube 12 goes back down in the pocket 1 by evacuating these two ducts.

L'action du vérin 21 est alors supprimée, l'ensemble moule-support 26 est écarté de la buse 6 sous l'action des ressorts 25, et l'ensemble du bâti 3 est éloigné horizontalement de la poche sur les rails 19.The action of the jack 21 is then eliminated, the mold-support assembly 26 is moved away from the nozzle 6 under the action of the springs 25, and the assembly of the frame 3 is moved away horizontally from the pocket on the rails 19.

Grâce au dimensionnement des canaux 30A, 30B indiqué plus haut, et en assurant par le conduit 14 un débit de gaz approprié, le metal liquide monte rapidement dans le puits 28, assurant une hauteur métallostatique suffisante pour alimenter chaque empreinte individuellement par son couple de canaux 30A et 30B. Ceci permet d'obtenir un remplissage équilibré et simultané de toutes les empreintes, quel que soit l'étage et quelle que soit leur forme. De plus, l'étroitesse des canaux intermédiaires limite le débit de métal qui s'y écoule, ce qui conduit d'une part à un déplacement minimal de métal à chaque coulée, et d'autre part à un remplissage mieux contrôlé et plus calme des empreintes. Il en résulte finalement une amélioration de la santé des pièces coulées.Thanks to the dimensioning of the channels 30A, 30B indicated above, and by ensuring through the conduit 14 an appropriate gas flow, the liquid metal rises rapidly in the well 28, ensuring a metallostatic height sufficient to supply each imprint individually by its pair of channels 30A and 30B. This makes it possible to obtain a balanced and simultaneous filling of all the imprints, whatever the floor and whatever their shape. In addition, the narrowness of the intermediate channels limits the flow of metal flowing therein, which leads on the one hand to a minimal displacement of metal at each pouring, and on the other hand to a better controlled and quieter filling prints. This ultimately results in an improvement in the health of the castings.

Il faut encore noter que l'utilisation des canaux intermédiaires comme obturateurs évite tout retour de métal notablement refroidi dans la poche, sans réduire le rendement en métal. Ceci est très avantageux pour la reproductibilité des conditions de coulée. De plus, le métal légèrement refroidi contenu dans le puits de coulée est, à la coulée suivante, réparti entre toutes les empreintes du moule, et le bilan thermique est particulièrement favorable.It should also be noted that the use of intermediate channels as plugs prevents any return of significantly cooled metal in the pocket, without reducing the yield of metal. This is very advantageous for the reproducibility of the casting conditions. In addition, the slightly cooled metal contained in the pouring well is, on the next casting, distributed between all of the mold cavities, and the thermal balance is particularly favorable.

Claims (8)

Procédé pour alimenter plusieurs empreintes (31) d'un même étage d'un moule en sable borgne (4), en coulée de métal sous basse pression notamment multiétages, l'alimentation s'effectuant via un puits de coulée (28), au moins un canal intermédiaire (30A, 30B) et des attaques (32A, 32B), caractérisé en ce qu'on affecte à chaque canal uniquement des attaques débouchant dans une seule empreinte.Method for feeding several cavities (31) of the same stage of a blind sand mold (4), in metal casting under low pressure, in particular multi-stage, the supply taking place via a casting well (28), at the at least one intermediate channel (30A, 30B) and attacks (32A, 32B), characterized in that only attacks leading to a single imprint are assigned to each channel. Procédé suivant la revendication 1, caractérisé en ce qu'on envoie dans le tube d'amenée un débit de métal liquide adapté pour provoquer une montée de ce métal au-dessus de tous les canaux intermédiaires (30A, 30B).Method according to claim 1, characterized in that a flow of liquid metal adapted to cause a rise of this metal over all of the intermediate channels (30A, 30B) is sent into the supply tube. Procédé suivant la revendication 1 ou 2, cractérisé en ce qu'on maintient la pression d'alimentation du moule jusqu'à solidification de tous les canaux intermédiaires (30A, 30B), puis on relâche cette pression.Method according to claim 1 or 2, characterized in that the mold supply pressure is maintained until all the intermediate channels (30A, 30B) solidify, then this pressure is released. Moule en sable borgne pour la mise en oeuvre d'un procédé suivant l'une quelconque des revendications 1 à 3,du type comprenant un puits de coulée (28) et au moins un étage où sont prévues plusieurs empreintes (31), ces empreintes étant alimentées via des attaques (32A, 32B) reliées au puits de coulée par au moins un canal intermédiaire (30A, 30B), caractérisé en ce que toutes les attaques alimentées par un même canal intermédiaire débouchent dans la même empreinte.Mold in blind sand for the implementation of a method according to any one of claims 1 to 3, of the type comprising a pouring well (28) and at least one stage where several imprints (31) are provided, these imprints being fed via attacks (32A, 32B) connected to the tapping well by at least one intermediate channel (30A, 30B), characterized in that all the attacks fed by the same intermediate channel lead to the same footprint. Moule en sable suivant la revendication 4, caractérisé en ce que chaque empreinte (31) est alimentée par deux canaux intermédiaires (30A, 30B) s'étendant de part et d'autre du puits de coulée (28).Sand mold according to claim 4, characterized in that each cavity (31) is supplied by two intermediate channels (30A, 30B) extending on either side of the casting well (28). Moule en sable suivant la revendication 4 ou 5, caractérisé en ce que la somme des aires des sections d'entrée des canaux intermédiaires (30A, 30B) d'un étage est nettement inférieure à l'aire de la section du puits de coulée (28).Sand mold according to claim 4 or 5, characterized in that the sum of the areas of the inlet sections of the intermediate channels (30A, 30B) of a stage is significantly less than the area of the section of the taphole (28). Moule suivant l'une quelconque des revendications 4 à 6, caractérisé en ce qu'il est multiétages.Mold according to any one of Claims 4 to 6, characterized in that it is multi-stage. Installation de coulée de métal sous basse pression en moule en sable borgne, du type comprenant une poche de coulée (1) d'où part un tube d'amenée (12) ouvert vers le haut, une source (13) de gaz sous pression reliée à la poche, au moins un moule en sable borgne (4) comprenant un puits de coulée (28) ouvert vers le bas et au moins un étage où sont prévues plusieurs empreintes (31), ces empreintes étant alimentées via des attaques (32A, 32B) reliées au puits de coulée par au moins un canal intermédiaire (30A, 30B), et des moyens (21) pour appliquer la base du puits de coulée sur l'ouverture du tube d'amenée, caractérisé en ce que le moule est conforme à l'une quelconque des revendications 4 à 7.Installation of low pressure metal casting in a blind sand mold, of the type comprising a casting ladle (1) from which a supply tube (12) open upwards, a source (13) of pressurized gas connected to the pocket, at least one blind sand mold (4) comprising a pouring well (28) open at the bottom and at least one stage where several imprints (31) are provided, these imprints being supplied via attacks (32A , 32B) connected to the tapping well by at least one intermediate channel (30A, 30B), and means (21) for applying the base of the tapping well to the opening of the supply tube, characterized in that the mold is in accordance with any of claims 4 to 7.
EP91401543A 1990-06-22 1991-06-11 Process and device for feeding a sand mould with liquid metal using low pressure Expired - Lifetime EP0463910B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9007862 1990-06-22
FR9007862A FR2663572B1 (en) 1990-06-22 1990-06-22 METHOD FOR SUPPLYING LOW PRESSURE METAL OF A CORD SAND MOLD, MOLD AND CORRESPONDING CAST INSTALLATION.

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EP0463910A1 true EP0463910A1 (en) 1992-01-02
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EP (1) EP0463910B1 (en)
JP (1) JPH0798258B2 (en)
AT (1) ATE110998T1 (en)
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CA (1) CA2044880C (en)
CS (1) CS188391A3 (en)
DE (1) DE69103826T2 (en)
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CN104148613A (en) * 2014-08-21 2014-11-19 无锡蠡湖叶轮制造有限公司 One-die-four-cavity die for compressor casing low-pressing casting

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DE19900574A1 (en) * 1999-01-09 2000-07-13 Georg Fischer Disa Ag Method and device for increasing the casting of light metal
DE10033625A1 (en) * 2000-07-11 2002-01-31 Vaw Ver Aluminium Werke Ag Method and device for rising casting with a mold / core package with an open gate
US8770265B2 (en) 2011-12-28 2014-07-08 Bedloe Industries Llc Method and system for manufacturing railcar couplers
JP5646025B2 (en) * 2013-09-27 2014-12-24 三菱重工業株式会社 Turbine blade mold and turbine blade manufacturing method
JP6350050B2 (en) * 2014-07-10 2018-07-04 大同特殊鋼株式会社 Vacuum suction casting method
CN109128041B (en) * 2018-11-09 2019-12-10 重庆擎一模具制造有限公司 Upset casting die
CN109226684A (en) * 2018-11-27 2019-01-18 禹州市昆仑模具有限公司 A kind of punch-pin of uncoupling lever bracket precoated sand mold

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NO179066B (en) 1996-04-22
EP0463910B1 (en) 1994-09-07
FI913011A0 (en) 1991-06-19
MX173081B (en) 1994-01-31
FR2663572B1 (en) 1994-11-25
PL290759A1 (en) 1992-02-24
DE69103826D1 (en) 1994-10-13
ATE110998T1 (en) 1994-09-15
RU2046692C1 (en) 1995-10-27
PL167599B1 (en) 1995-09-30
FI96099B (en) 1996-01-31
DK0463910T3 (en) 1994-10-10
CS188391A3 (en) 1992-06-17
FR2663572A1 (en) 1991-12-27
ES2060322T3 (en) 1994-11-16
NO912405L (en) 1991-12-23
FI96099C (en) 1996-05-10
CA2044880C (en) 1996-10-01
DE69103826T2 (en) 1995-01-05
NO912405D0 (en) 1991-06-20
NO179066C (en) 1996-07-31
JPH0798258B2 (en) 1995-10-25
HU912032D0 (en) 1991-12-30
HU207008B (en) 1993-03-01
US5385197A (en) 1995-01-31
FI913011A (en) 1991-12-23
JPH04251654A (en) 1992-09-08
BR9102617A (en) 1992-01-21
HUT58011A (en) 1992-01-28
CA2044880A1 (en) 1991-12-23

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