EP0408453A1 - Apparatus for an electromagnetic nozzle for controlling a jet of liquid metal - Google Patents
Apparatus for an electromagnetic nozzle for controlling a jet of liquid metal Download PDFInfo
- Publication number
- EP0408453A1 EP0408453A1 EP90402006A EP90402006A EP0408453A1 EP 0408453 A1 EP0408453 A1 EP 0408453A1 EP 90402006 A EP90402006 A EP 90402006A EP 90402006 A EP90402006 A EP 90402006A EP 0408453 A1 EP0408453 A1 EP 0408453A1
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- EP
- European Patent Office
- Prior art keywords
- crucible
- electromagnetic
- jet
- liquid metal
- magnetic field
- 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.)
- Granted
Links
- 229910001338 liquidmetal Inorganic materials 0.000 title claims abstract description 32
- 239000002184 metal Substances 0.000 claims description 13
- 229910052751 metal Inorganic materials 0.000 claims description 13
- 239000000843 powder Substances 0.000 claims description 10
- 229910000601 superalloy Inorganic materials 0.000 claims description 9
- 238000000889 atomisation Methods 0.000 claims description 7
- 239000000463 material Substances 0.000 claims description 7
- 239000007788 liquid Substances 0.000 claims description 6
- 230000008602 contraction Effects 0.000 claims description 5
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 4
- 229910052802 copper Inorganic materials 0.000 claims description 4
- 239000010949 copper Substances 0.000 claims description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 3
- 238000002844 melting Methods 0.000 claims description 2
- 230000008018 melting Effects 0.000 claims description 2
- 230000035699 permeability Effects 0.000 claims description 2
- 230000000977 initiatory effect Effects 0.000 claims 1
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 12
- 238000009434 installation Methods 0.000 description 6
- 229910052759 nickel Inorganic materials 0.000 description 6
- 238000000034 method Methods 0.000 description 5
- 238000005266 casting Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 230000009467 reduction Effects 0.000 description 4
- 239000000919 ceramic Substances 0.000 description 3
- 238000005339 levitation Methods 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 239000011819 refractory material Substances 0.000 description 3
- 238000010894 electron beam technology Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000007670 refining Methods 0.000 description 2
- 238000005299 abrasion Methods 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 230000001143 conditioned effect Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010891 electric arc Methods 0.000 description 1
- 230000005674 electromagnetic induction Effects 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 238000005058 metal casting Methods 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 230000002028 premature Effects 0.000 description 1
- 230000010349 pulsation Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 210000003462 vein Anatomy 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
- B22D41/08—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like for bottom pouring
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D39/00—Equipment for supplying molten metal in rations
- B22D39/003—Equipment for supplying molten metal in rations using electromagnetic field
Definitions
- the present invention relates to an electromagnetic nozzle device which can be used in particular at the outlet of a crucible for the stabilized casting of a liquid metal with variable flow rate in the form of ultra-clean material intended in particular for the atomization of metal powders such as for manufacture of superalloy parts for aeronautical applications.
- the known and currently used methods for the preparation of superalloys involve melting operations in a crucible of refractory material of ceramic type carried out in a vacuum furnace . During this operation, a metal / ceramic reaction takes place, which inevitably results in the presence of ceramic inclusions in the material obtained. A refining of the superalloy is therefore made necessary each time the application conditions impose the obtaining of a so-called super-clean superalloy. This is particularly the case for nickel-based superalloys intended for aeronautical applications, such as parts of aeronautical turbine engines or other propulsion assemblies.
- Various known techniques are used to obtain such an inclusive refining, for example by remelting in a cooled crucible, the fusion being obtained either by electric arc, or by electron beam or by plasma beam.
- the contact between liquid metal and solid walls of the nozzle leads to double pollution of the metal: - On the one hand, chemical pollution due to the reaction of the liquid metal at high temperature with the oxides contained in the refractory materials constituting the walls; - on the other hand, physical pollution due to abrasion of the walls of the nozzle by the passage of molten metal.
- FR-A-2 316 026, FR-A-2 396 612 and FR-A-2 397 251 have thus described electromagnetic devices operating at high frequency in which a copper screen is necessary to obtain the desired confinement.
- the industrial implementation of such devices such as on an installation for atomizing powders of nickel-based superalloys, however presents serious difficulties.
- FR-A-2 457 730 can eliminate the copper screen, but the device operating at low frequency requires in many applications to use significant powers, not compatible with industrialization, as soon as significant reductions in the jet of liquid metal are becoming necessary, especially in powder atomization techniques.
- An electromagnetic nozzle device making it possible to avoid the drawbacks of known prior devices is characterized in that the electromagnetic induction with turns is associated with a magnetic field concentrator device disposed between said coil inductor and the outlet walls of the crucible which it surrounds externally, said magnetic field concentrator device consisting of four to eight three-dimensional sectors separated by radial slots, each sector comprising a diametrically external semi-cylindrical wall and a semi-wall -cylindrical diametrically internal, coaxial and of smaller height, the respective four edges of these walls being joined by planar portions and the cavity thus formed being cooled by water, said internal and external walls comprising turns forming an electromagnetic inductor.
- FIGS. 1 a and 1 b show detailed views of an electromagnetic nozzle device produced in accordance with the invention usable for controlling the jet of liquid metal, in particular at the outlet of the crucible of a installation for casting molten metal as partially shown in FIG. 2.
- the nozzle comprises an electromagnetic inductor 1, of a type known per se, comprising several turns 1 a and the implementation of which (power supplies, etc.) is also known per se and does not will not be the subject of a more detailed description.
- the inductor 1 is disposed at the outlet of a crucible 2 and externally surrounds the walls of said crucible. Between said inductor 1 and said walls of the crucible 2 is placed a device 3 magnetic field concentrator.
- the field concentrator 3 is sectorized and in fact, the field concentration effect appears as soon as a slot is present. To avoid deformation or deflection of the jet due to a higher magnetic field intensity in front of a slot, the field concentrator 3 is produced in an even number of equal sectors distributed symmetrically. For ease of production and in the applications targeted by the invention for the casting of metals or the atomization of superalloys, in particular based on nickel, the number of sectors provided is eight but it can be reduced to four.
- each sector 4 is made of copper plates and has a radially outer wall 4 has a semi-cylindrical wall arranged vertically relative to the crucible 2 and a wall radially internal 4b semi-cylindrical, coaxial with the previous one but of lower height.
- the respective four edges of these wall elements 4a and 4b are joined by four planar wall portions, upper 4c, lower 4d and lateral 4e and 4f. the internal cavity 5 thus formed inside each sector 4 is filled with cooling water.
- Each semi-cylindrical wall 4a and 4b has turns 6a and 7a so as to form an electromagnetic inductor.
- the sectors 4 of the magnetic field concentrator 3 are separated by radial slots 3a.
- the crucible 2 of a type known per se has walls 8 whose particular geometry makes it possible to keep most of the liquid metal 9 in levitation. Said walls 8 include cooling tubes 10 supplied by a water box 11. The liquid metal is discharged at the outlet of the crucible 2 through an orifice 12 masked by a cooled finger 13 capable of being retracted.
- the detail of the lower part of the crucible 2, opened after retraction of the finger 13, shown in FIG. 3 shows the evacuation of a jet of liquid metal from the crucible.
- the jet of liquid metal has a diameter coincident with that of the material nozzle 14 located at the bottom of the crucible 2.
- the metal jet has a reduction in section 15.
- the lower part of this crucible 20 schematically represented in the FIG. 4 comprises an orifice 31 at the level of which the concentrator 3 of magnetic fields is positioned which causes a reduction in section 15 which separates the metal from contact with the wall 32a of the material nozzle 32.
- the restoring force is obtained when the magnetic field generates an increasing force in the radial direction from the surface of the jet, which causes, in conservative flux, a similar variation in the axial direction.
- the efficiency of the device increases with frequency. Increasing the frequency also has the advantage of reducing the mixing effects of the liquid metal.
- practical limits which can be determined experimentally for each application are imposed on the frequencies.
- a maximum frequency f2 is thus determined from the following criteria: - limitation of the powers used; - risks of electric strikes between the different sectors 4 of the magnetic field concentrator 3 or between them and the metal jet:; - increase with the frequency of losses in the inductor 1 and the field concentrator 3; - device efficiency measured by the contraction coefficient X, expressed in percent and defined by: X (de - ds) / de with de, diameter of the liquid stream at the inlet of the nozzle and ds, diameter of the liquid stream at the outlet of the nozzle.
- a frequency domain f such as: 100 Hz ⁇ f, ⁇ 106 Hz in which the jet of liquid metal is not only channeled but also contracted is thus obtained.
- the electromagnetic nozzle device with field concentrator device thus makes it possible to ensure, by means of a choice of implementation parameters adapted to each application according to the criteria which have been indicated. the desired results and in particular a separation of the liquid metal from the walls of the reflow crucible, in particular at the level of the material nozzle leaving the crucible, thus avoiding any contact between walls and liquid metal and thereby any risk of pollution.
- the device also has the advantage of ensuring stability of the jet of liquid metal contracted over a significant distance and thus a laminar flow is obtained over a distance which can be greater than ten times the outlet diameter of the electromagnetic nozzle.
- the compactness of the device according to the invention facilitates the installation at the outlet of the crucible of an installation of the "super clean" type of reflow by electron beam, by plasma beam or, as in the example described, by reflow in a cold crucible, a casting installation (in a mold for example) or finally a powder atomization installation.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Manufacture Of Metal Powder And Suspensions Thereof (AREA)
- Continuous Casting (AREA)
- Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
Abstract
Description
La présente invention concerne un dispositif de busette électro-magnétique utilisable notamment à la sortie d'un creuset pour la coulée stabilisée d'un métal liquide à débit variable sous forme de matériau ultrapropre destiné notamment à l'atomisation de poudres métalliques telles que pour la fabrication de pièces en superalliages pour applications aéronautiques.The present invention relates to an electromagnetic nozzle device which can be used in particular at the outlet of a crucible for the stabilized casting of a liquid metal with variable flow rate in the form of ultra-clean material intended in particular for the atomization of metal powders such as for manufacture of superalloy parts for aeronautical applications.
Les procédés connus et actuellement utilisés pour l'élaboration de superalliages, notamment à base de nickel tels que ceux qui sont particulièrement visés par la présente invention, font intervenir des opérations de fusion en creuset en matériau réfractaire de type céramique réalisées dans un four sous vide. Lors de cette opération il se produit une réaction métal/céramique d'où il résulte inévitablement la présence d'inclusions céramiques dans le matériau obtenu. Un affinage du superalliage est par conséquent rendu nécessaire à chaque fois que les conditions des applications imposent l'obtention d'un superalliage dit super-propre. C'est notamment le cas pour des superalliages à base de nickel destinés à des applications aéronautiques, telles que des pièces de moteurs aéronautiques à turbine ou d'autres ensembles de propulsion. Diverses techniques connues sont employées pour obtenir un tel affinage inclusionnaire, par exemple par refusion en creuset refroidi, la fusion étant obtenue soit par arc électrique, soit par faisceau d'électrons ou par faisceau plasma.The known and currently used methods for the preparation of superalloys, in particular based on nickel such as those which are particularly targeted by the present invention, involve melting operations in a crucible of refractory material of ceramic type carried out in a vacuum furnace . During this operation, a metal / ceramic reaction takes place, which inevitably results in the presence of ceramic inclusions in the material obtained. A refining of the superalloy is therefore made necessary each time the application conditions impose the obtaining of a so-called super-clean superalloy. This is particularly the case for nickel-based superalloys intended for aeronautical applications, such as parts of aeronautical turbine engines or other propulsion assemblies. Various known techniques are used to obtain such an inclusive refining, for example by remelting in a cooled crucible, the fusion being obtained either by electric arc, or by electron beam or by plasma beam.
Quelle que soit la technique employée, toutefois, lors de la coulée des métaux en fusion pour utilisation, qu'il s'agisse du remplissage d'un moule ou d'une atomisation du métal liquide pour obtenir des poudres, il devient nécessaire soit d'opérer un basculement du four, dans un premier cas, soit d'utiliser à la sortie du métal liquide une busette en matériau réfractaire, dans un second cas. Dans le premier cas, le contrôle du débit et de la masse du métal en fusion ne peut guère être obtenu et dans le second cas où ce problème est résolu, d'autres inconvénients apparaissent :
- des diamètres de busette assez importants sont imposés afin d'éviter le risque de bouchage ;
- instabilité du jet de métal liquide ;
- difficultés importantes pour faire varier le diamètre du jet liquide en cours d'opération.Whatever technique is used, however, when casting molten metals for use, whether filling a mold or atomizing the liquid metal to obtain powders, it becomes necessary either 'operate a tilting of the oven, in a first case, or to use at the outlet of the liquid metal a nozzle of refractory material, in a second case. In the first case, the control of the flow rate and the mass of the molten metal can hardly be obtained and in the second case where this problem is solved, other drawbacks appear:
- fairly large nozzle diameters are imposed in order to avoid the risk of clogging;
- instability of the liquid metal jet;
- significant difficulties in varying the diameter of the liquid jet during operation.
Par ailleurs, le contact entre métal liquide et parois solides de la busette entraîne une double pollution du métal :
- d'une part, une pollution chimique dûe à la réaction du métal liquide à haute température avec les oxydes contenus dans les matériaux réfractaires constituant les parois ;
- d'autre part, une pollution physique dûe à l'abrasion des parois de la busette par le passage du métal en fusion.Furthermore, the contact between liquid metal and solid walls of the nozzle leads to double pollution of the metal:
- On the one hand, chemical pollution due to the reaction of the liquid metal at high temperature with the oxides contained in the refractory materials constituting the walls;
- on the other hand, physical pollution due to abrasion of the walls of the nozzle by the passage of molten metal.
Dans des applications particulières notamment de techniques connues d'élaboration par atomisation par gaz de métaux liquides, ces pollutions entraînent la présence de nombreuses inclusions dans les poudres métalliques et il est notamment reconnu que la présence de telles inclusions dans des pièces tournantes de moteurs aéronautiques, par exemple à base de nickel, peut être à l'origine de défauts de tenue en service de ces pièces soumises à des sollicitations en fatigue oligocyclique et entraîne notamment des ruptures prématurées de pièces soumises à de fortes contraintes à haute température. Ces problèmes ont conduit à réduire la taille des grains des poudres, ce qui aboutit à des rendements granulométriques très médiocres dans l'élaboration de ces poudres. Des tentatives de solution ont été proposées, sur la base de l'utilisation d'une busette électromagnétique qui permet le confinement du jet de métal liquide sans contact avec les parois. FR-A-2 316 026, FR-A-2 396 612 et FR-A-2 397 251 ont ainsi décrit des dispositifs électro-magnétiques fonctionnant à haute fréquence dans lesquels un écran en cuivre est nécessaire pour obtenir le confinement souhaité.
La mise en oeuvre industrielle de tels dispositifs, telle que sur une installation d'atomisation de poudres de superalliages à base de nickel, présente toutefois de sérieuses difficultés. FR-A-2 457 730 peut éliminer l'écran en cuivre, mais le dispositif fonctionnant à fréquence basse impose dans de nombreuses applications de faire appel à des puissances importantes, peu compatibles avec l'industrialisation, dès que des réductions importantes du jet de métal liquide deviennent nécessaires, notamment dans les techniques d'atomisation de poudres.In particular applications, in particular of known techniques of preparation by atomization by gas of liquid metals, these pollutions cause the presence of numerous inclusions in the metallic powders and it is in particular recognized that the presence of such inclusions in rotating parts of aeronautical engines, for example based on nickel, can be the cause of defects in service performance of these parts subjected to oligocyclic fatigue stresses and in particular causes premature ruptures of parts subjected to high stresses at high temperature. These problems have led to a reduction in the grain size of the powders, which results in very poor particle size yields in the preparation of these powders. Attempts at a solution have been proposed, on the basis of the use of an electromagnetic nozzle which allows the confinement of the jet of liquid metal without contact with the walls. FR-A-2 316 026, FR-A-2 396 612 and FR-A-2 397 251 have thus described electromagnetic devices operating at high frequency in which a copper screen is necessary to obtain the desired confinement.
The industrial implementation of such devices, such as on an installation for atomizing powders of nickel-based superalloys, however presents serious difficulties. FR-A-2 457 730 can eliminate the copper screen, but the device operating at low frequency requires in many applications to use significant powers, not compatible with industrialization, as soon as significant reductions in the jet of liquid metal are becoming necessary, especially in powder atomization techniques.
Un dispositif de busette électromagnétique permettant d'éviter les inconvénients des dispositifs antérieurs connus est caractérisé en ce que l'induction électromagnétique à spires est associé à un dispositif concentreur de champ magnétique disposé entre ledit inducteur à spires et les parois de sortie du creuset qu'il entoure extérieurement, ledit dispositif concentreur de champ magnétique étant constitué de quatre à huit secteurs tridimensionnels séparés par des fentes radiales, chaque secteur comportant une paroi hémi-cylindrique diamétralement externe et une paroi hémi-cylindrique diamétralement interne, coaxiale et de plus faible hauteur, les quatre bords respectifs de ces parois étant réunis par des portions planes et la cavité ainsi formée étant refroidie par eau, lesdites parois interne et externe comportant des spires formant un inducteur électromagnétique.An electromagnetic nozzle device making it possible to avoid the drawbacks of known prior devices is characterized in that the electromagnetic induction with turns is associated with a magnetic field concentrator device disposed between said coil inductor and the outlet walls of the crucible which it surrounds externally, said magnetic field concentrator device consisting of four to eight three-dimensional sectors separated by radial slots, each sector comprising a diametrically external semi-cylindrical wall and a semi-wall -cylindrical diametrically internal, coaxial and of smaller height, the respective four edges of these walls being joined by planar portions and the cavity thus formed being cooled by water, said internal and external walls comprising turns forming an electromagnetic inductor.
Les résultats remarquables obtenus sont également conditionnés par le choix de paramètres spécifiques de dimensionnement ainsi que par des paramètres déterminés de définition du champ magnétique appliqué, notamment la fréquence et l'intensité du champ.
D'autres caractéristiques et avantages de l'invention seront mieux compris à la lecture de la description qui va suivre d'un mode de réalisation de l'invention, en référence aux dessins annexés sur lesquels :
- - la figure 1a représente, selon une demi-vue schématique en coupe par un plan vertical passant par l'axe de symétrie, un dispositif de busette électromagnétique conforme à l'invention,
- - la figure 1b représente, selon une demi-vue schématique en coupe par un plan horizontal, le dispositif concentreur de champ magnétique de la busette électromagnétique représentée à la figure 1a ;
- - la figure 2 représente, selon une vue schématique en coupe par un plan vertical, un creuset d'un type connu dit creuset refroidi de lévitation équipé du dispositif de busette électromagnétique représenté sur les figures 1a et 1b ;
- - La figure 3 montre un détail de la figure 2 lors de l'évacuation d'un jet de métal liquide hors du creuset;
- - La figure 4 montre un détail analogue à celui de la figure 3 dans le cas de l'application du dispositif de busette électromagnétique conforme à l'invention à un creuset réfractaire classique.
Other characteristics and advantages of the invention will be better understood on reading the description which follows of an embodiment of the invention, with reference to the appended drawings in which:
- - Figure 1 a is a diagrammatic half-view in section through a vertical plane passing through the axis of symmetry, an electromagnetic nozzle device according to the invention,
- - Figure 1 b shows, in a schematic half sectional view in a horizontal plane, the magnetic field concentrator device of electromagnetic nozzle shown in Figure 1a;
- - Figure 2 shows, in a schematic sectional view through a vertical plane, a crucible of a known type said cooled crucible levitation equipped with the electromagnetic nozzle device shown in Figures 1 a and 1 b;
- - Figure 3 shows a detail of Figure 2 during the evacuation of a jet of liquid metal out of the crucible;
- - Figure 4 shows a detail similar to that of Figure 3 in the case of the application of the electromagnetic nozzle device according to the invention to a conventional refractory crucible.
Les figures 1a et 1b montrent des vues de détail d'un dispositif de busette électromagnétique réalisé conformément à l'invention utilisable pour le contrôle de jet de métal liquide, notamment en sortie de creuset d'une installation de coulée de métal en fusion telle que partiellement représentée sur la figure 2. La busette comporte un inducteur électromagnétique 1, d'un type connu en soi, comportant plusieurs spires 1a et dont la mise en oeuvre (alimentations etc...) est également connue en soi et ne fera pas l'objet d'une description plus détaillée. L'inducteur 1 est disposé à la sortie d'un creuset 2 et entoure extérieurement les parois dudit creuset. Entre ledit inducteur 1 et lesdites parois du creuset 2 est placé un dispositif 3 concentreur de champ magnétique. Le concentreur de champ 3 est sectorisé et en fait, l'effet de concentration du champ apparaît dès la présence d'une fente. Pour éviter une déformation ou une déviation du jet dues à une intensité de champ magnétique plus élevée en face d'une fente, le concentreur de champ 3 est réalisé en un nombre pair de secteurs égaux répartis symétriquement. Pour des facilités de réalisation et dans les applications visées par l'invention à la coulée de métaux ou à l'atomisation de superalliages, notamment à base de nickel, le nombre de secteurs prévus est de huit mais il peut être réduit à quatre. selon le mode de réalisation d'une géométrie particulière des secteurs 4 du concentreur de champ 3 conforme à l'invention et représenté sur les figures 1a, 1b, et 2, chaque secteur 4 est réalisé en plaques de cuivre et présente une paroi radialement externe 4a hémi-cylindrique disposée verticalement par rapport au creuset 2 et une paroi radialement interne 4b hémi-cylindrique, coaxiale à la précédente mais de hauteur plus faible. Les quatre bords respectifs de ces éléments de paroi 4a et 4b sont réunis par quatre portions de paroi planes, supérieure 4c, inférieure 4d et latérales 4e et 4f. la cavité interne 5 ainsi formée à l'intérieur de chaque secteur 4 est remplie d'eau de refroidissement. Chaque paroi hémi-cylindrique 4a et 4b comporte des spires 6a et 7a de manière à former un inducteur électromagnétique. Les secteurs 4 du concentreur de champ magnétique 3 sont séparés par des fentes radiales 3a. Le creuset 2 d'un type connu en soi comporte des parois 8 dont la géométrie particulière permet de maintenir la majeure partie du métal liquide 9 en lévitation. Lesdites parois 8 comportent des tubes 10 de refroidissement alimentés par une boîte à eau 11. Le métal liquide est évacué à la sortie du creuset 2 par un orifice 12 masqué par un doigt refroidi 13 susceptible d'être escamoté.FIGS. 1 a and 1 b show detailed views of an electromagnetic nozzle device produced in accordance with the invention usable for controlling the jet of liquid metal, in particular at the outlet of the crucible of a installation for casting molten metal as partially shown in FIG. 2. The nozzle comprises an
Le détail de la partie inférieure du creuset 2, ouvert après escamotage du doigt 13, représenté sur la figure 3 montre l'évacuation d'un jet de métal liquide hors du creuset. A l'origine, à la partie supérieure de la sortie du creuset, le jet de métal liquide a un diamètre confondu avec celui de la busette matérielle 14 située en bas du creuset 2. Dès que la veine de métal liquide arrive à la hauteur du concentreur 3 de champ magnétique de la busette électromagnétique, le jet de métal a une réduction de section 15.The detail of the lower part of the crucible 2, opened after retraction of the
Si on utilise au lieu d'un creuset froid de lévitation, tel que représenté sur les figures 2 et 3, un creuset réfractaire classique, destiné par exemple à l'atomisation de poudres, la partie inférieure de ce creuset 20, schématiquement représentée sur la figure 4 comporte un orifice 31 au niveau duquel est positionné le concentreur 3 de champs magnétique qui provoque une réduction de section 15 qui écarte le métal du contact avec la paroi 32a de la busette matérielle 32.If, instead of a cold levitation crucible, as shown in FIGS. 2 and 3, a conventional refractory crucible, intended for example for the atomization of powders, is used, the lower part of this
Ce résultat est obtenu grâce à la création d'un champ magnétique intense sur une zone très localisée qui résulte de l'emploi de la busette électromagnétique à concentreur 3 de champ magnétique conforme à l'invention. Un inducteur classique à spires devant produire le même résultat aurait un encombrement très important, incompatible avec les contraintes imposées par le contrôle du jet de métal liquide. En fait, par le choix adapté à l'application de paramètres de dimensionnement et de position adéquate de la busette électromagnétique et notamment du concentreur 3 de champ magnétique, des forces axisymétriques dirigées vers l'axe du jet de métal liquide sont engendrées. Si le jet se rapproche de la paroi 14a, ladite busette électromagnétique crée une force de rappel qui recentre le jet dans l'axe de la busette. Cette force de rappel nécessite un champ magnétique intense dont la fréquence minimale doit être telle que la profondeur de pénétration du champ magnétique et de ses courants induits dans le jet soit inférieur au rayon R du jet de métal liquide, ce qui est exprimé par la relation suivante :
µ σ ω R² > 2
dans laquelle : - µ est la perméabilité magnétique dans le vide
- σ est la conductivité électrique du métal liquide,
- R est le rayon du jet de métal liquide,
- ω est la pulsation du champ magnétique, reliée à la fréquence f par ω = 2 π f,
La fréquence minimale f₁ obtenue est donc :
f₁ = 1 /π ω σ R²This result is obtained by the creation of an intense magnetic field over a very localized area which results from the use of the electromagnetic nozzle with
µ σ ω R²> 2
in which: - µ is the magnetic permeability in a vacuum
- σ is the electrical conductivity of the liquid metal,
- R is the radius of the liquid metal jet,
- ω is the pulsation of the magnetic field, connected to the frequency f by ω = 2 π f,
The minimum frequency f₁ obtained is therefore:
f₁ = 1 / π ω σ R²
La force de rappel est obtenue lorsque le champ magnétique engendre une force croissante dans la direction radiale à partir de la surface du jet, ce qui entraîne, à flux conservatif, une variation semblable dans la direction axiale. Compte tenu de l'exploitation d'un effet de pression essentiellement surfacique, l'efficacité du dispositif augmente avec la fréquence. L'augmentation de fréquence a également l'avantage de réduire les effets de brassage du métal liquide. Des limites pratiques qui peuvent être déterminées expérimentalement pour chaque application sont toutefois imposées aux fréquences. Une fréquence maximale f₂ est ainsi déterminée à partir des critères suivants :
- limitation des puissances mises en oeuvre ;
- risques d'amorçages électriques entre les différents secteurs 4 du concentreur 3 de champ magnétique ou entre ceux-ci et le jet métallique :;
- augmentation avec la fréquence des pertes dans l'inducteur 1 et le concentreur de champ 3 ;
- efficacité du dispositif mesurée par le coefficient de contraction X, exprimé en pourcents et défini par :
X ( de - ds) / de
avec de, diamètre de la veine liquide en entrée de la busette et ds, diamètre de la veine liquide en sortie de la busette.The restoring force is obtained when the magnetic field generates an increasing force in the radial direction from the surface of the jet, which causes, in conservative flux, a similar variation in the axial direction. Taking into account the exploitation of an essentially surface pressure effect, the efficiency of the device increases with frequency. Increasing the frequency also has the advantage of reducing the mixing effects of the liquid metal. However, practical limits which can be determined experimentally for each application are imposed on the frequencies. A maximum frequency f₂ is thus determined from the following criteria:
- limitation of the powers used;
- risks of electric strikes between the
- increase with the frequency of losses in the
- device efficiency measured by the contraction coefficient X, expressed in percent and defined by:
X (de - ds) / de
with de, diameter of the liquid stream at the inlet of the nozzle and ds, diameter of the liquid stream at the outlet of the nozzle.
Un domaine de fréquences f tel que :
100 Hz < f, < 10⁶ Hz dans lequel le jet de métal liquide est non seulement canalisé mais aussi contracté est ainsi obtenu.A frequency domain f such as:
100 Hz <f, <10⁶ Hz in which the jet of liquid metal is not only channeled but also contracted is thus obtained.
L'intensité B du champ magnétique appliqué est déterminée en fonction de la pression magnétique Pm exercée à la périphérie du jet de métal liquide pour contrebalancer les effets de la tension superficielle et les forces d'inertie et qui est recherchée dans l'application concernée, suivant la relation :
Pm = B² / 2 µThe intensity B of the applied magnetic field is determined as a function of the magnetic pressure P m exerted on the periphery of the jet of liquid metal to counterbalance the effects of surface tension and the forces of inertia and which is sought in the application concerned , depending on the relationship:
Pm = B² / 2 µ
L'application de ces conditions à un échantillon de superalliage à base de nickel refondu dans le creuset 2, représenté sur la figure 2, dans lequel le diamètre de la busette matérielle 14 est de 15 mm a permis d'obtenir un diamètre 2R de métal liquide en sortie de la busette électromagnétique de 6mm, soit un coefficient X de contraction, tel que défini précédemment, de 60 %.The application of these conditions to a sample of nickel-based superalloy melted in crucible 2, shown in FIG. 2, in which the diameter of the
Les résultats suivants sont obtenus, exprimés en valeurs du coefficient X de contraction en fonction de la plage des fréquences appliquées :
Pour 10² Hz < f < 10⁶ Hz, X > 10 %
pour f < 10² Hz ou f > 10⁶ Hz, X < 10 %
et pour 5.10³ Hz < f < 5.10⁵ Hz, X > 50 %.The following results are obtained, expressed in values of the coefficient X of contraction as a function of the range of frequencies applied:
For 10² Hz <f <10⁶ Hz, X> 10%
for f <10² Hz or f> 10⁶ Hz, X <10%
and for 5.10³ Hz <f <5.10⁵ Hz, X> 50%.
Le dispositif de busette électromagnétique à dispositif concentreur de champ conforme à l'invention et qui vient d'être décrit permet ainsi d'assurer au moyen d'un choix de paramètres de mise en oeuvre adaptés à chaque application selon les critères qui ont été indiqués les résultats recherchés et notamment un décollement du métal liquide des parois du creuset de refusion, notamment au niveau de la busette matérielle de sortie du creuset, évitant ainsi tout contact entre parois et métal liquide et par là, tout risque de pollution.The electromagnetic nozzle device with field concentrator device according to the invention and which has just been described thus makes it possible to ensure, by means of a choice of implementation parameters adapted to each application according to the criteria which have been indicated. the desired results and in particular a separation of the liquid metal from the walls of the reflow crucible, in particular at the level of the material nozzle leaving the crucible, thus avoiding any contact between walls and liquid metal and thereby any risk of pollution.
Le dispositif présente en outre l'avantage d'assurer une stabilité du jet de métal liquide contracté sur une distance importante et ainsi un écoulement laminaire est obtenu sur une distance qui peut être supérieure à dix fois le diamètre de sortie de la busette électromagnétique.Enfin, la compacité du dispositif conforme à l'invention facilite la mise en place en sortie de creuset d'une installation de type "superpropre" de refusion par faisceau d'électrons, par faisceau plasma ou, comme dans l'exemple décrit, de refusion en creuset froid, d'une installation de coulée (en moule par exemple) ou enfin d'une installation d'atomisation de poudres.The device also has the advantage of ensuring stability of the jet of liquid metal contracted over a significant distance and thus a laminar flow is obtained over a distance which can be greater than ten times the outlet diameter of the electromagnetic nozzle. , the compactness of the device according to the invention facilitates the installation at the outlet of the crucible of an installation of the "super clean" type of reflow by electron beam, by plasma beam or, as in the example described, by reflow in a cold crucible, a casting installation (in a mold for example) or finally a powder atomization installation.
Claims (6)
f1 = 1 / π µ σ R²
dans laquelle µ est la perméabilité magnétique dans le vide ;
σ , la conductivité électrique du métal liquide concerné
R , le rayon du jet de métal liquide,
et une fréquence maximale f₂ déterminée expérimentalement en tenant compte des facteurs suivants :
- puissance disponible,
- risques d'amorçage,
- limitation des pertes dans l'inducteur et dans le concentreur de champ
- efficacité mesurée par le coefficient de contraction X, tel que : X = (de - ds) / de avec de, diamètre de la veine liquide en entrée de la busette, et ds, diamètre de la veine liquide en sortie de la busette.
tandis que l'intensité B du champ magnétique appliqué est relié à la pression magnétique Pm recherchée s'exerçant à la périphérie du jet par la relation :
Pm = B² / 2 µ4. Electromagnetic nozzle device according to any one of the preceding claims, in which the magnetic field applied to the jet of molten metal has a frequency situated in an optimal range which is defined for each application between a minimum frequency f₁ given by the following formula:
f1 = 1 / π µ σ R²
in which µ is the magnetic permeability in a vacuum;
σ, the electrical conductivity of the liquid metal concerned
R, the radius of the liquid metal jet,
and a maximum frequency f₂ determined experimentally taking into account the following factors:
- available power,
- risk of initiation,
- limitation of losses in the inductor and in the field concentrator
- Efficiency measured by the contraction coefficient X, such that: X = (de - ds) / de with de, diameter of the liquid stream entering the nozzle, and ds, diameter of the liquid stream leaving the nozzle.
while the intensity B of the applied magnetic field is related to the desired magnetic pressure Pm exerted on the periphery of the jet by the relation:
Pm = B² / 2 µ
5.10³ Hz < f < 5.10⁵ Hz5. An electromagnetic nozzle device according to claim 4, in which said optimal range of frequencies f of the magnetic field for a contraction coefficient X greater than 50% is located in:
5.10³ Hz <f <5.10⁵ Hz
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8909369A FR2649625B1 (en) | 1989-07-12 | 1989-07-12 | ELECTROMAGNETIC NOZZLE DEVICE FOR THE CONTROL OF A LIQUID METAL JET |
| FR8909369 | 1989-07-12 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0408453A1 true EP0408453A1 (en) | 1991-01-16 |
| EP0408453B1 EP0408453B1 (en) | 1993-03-31 |
Family
ID=9383711
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP90402006A Expired - Lifetime EP0408453B1 (en) | 1989-07-12 | 1990-07-12 | Apparatus for an electromagnetic nozzle for controlling a jet of liquid metal |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US5074532A (en) |
| EP (1) | EP0408453B1 (en) |
| JP (1) | JPH0645810B2 (en) |
| DE (1) | DE69001217T2 (en) |
| FR (1) | FR2649625B1 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0486830A2 (en) * | 1990-11-17 | 1992-05-27 | Eckart-Werke Standard Bronzepulver-Werke Carl Eckart Gmbh & Co. | Process for the atomisation of molten metal to produce metal powders |
| EP0539051A1 (en) * | 1991-10-21 | 1993-04-28 | General Electric Company | Direct processing of electroslag refined metal |
| EP0549984A2 (en) * | 1991-12-20 | 1993-07-07 | National Research Institute For Metals | Levitating and fusing device |
| EP0636848A1 (en) * | 1993-07-29 | 1995-02-01 | Imphy S.A. | Smelting process of electrically-conductive materials in an induction smelting furnace with a cold crucible and furnace therefor |
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| US5272718A (en) * | 1990-04-09 | 1993-12-21 | Leybold Aktiengesellschaft | Method and apparatus for forming a stream of molten material |
| DE4222399C2 (en) * | 1992-07-08 | 2001-06-07 | Ald Vacuum Techn Ag | Pouring nozzle guide funnel |
| US5261611A (en) * | 1992-07-17 | 1993-11-16 | Martin Marietta Energy Systems, Inc. | Metal atomization spray nozzle |
| DE4319128C1 (en) * | 1993-06-09 | 1995-02-23 | Fraunhofer Ges Forschung | Method and device for the free-forming production of three-dimensional components of a predetermined shape |
| US5598200A (en) * | 1995-01-26 | 1997-01-28 | Gore; David W. | Method and apparatus for producing a discrete droplet of high temperature liquid |
| US6217825B1 (en) * | 1996-08-03 | 2001-04-17 | Dider Werke Ag | Device and fireproof nozzle for the injection and/or casting of liquid metals |
| FR2773820B1 (en) * | 1998-01-22 | 2000-02-25 | Snecma | LIQUID METALLIC FIBER COATING PROCESS |
| FR2779363B1 (en) * | 1998-06-08 | 2001-01-19 | Bruno Jean Marie Aubert | METHOD FOR ACCELERATING AND GUIDING FLUIDS IN AN ELECTROMAGNETIC FIELD. IMPLEMENTATION ON A FIRE HOSE TO INCREASE THE SCOPE |
| FR2788709B1 (en) * | 1999-01-21 | 2001-02-23 | Snecma | PROCESS FOR FEEDING A LEVITATION CRUCIBLE |
| EP1632593B1 (en) * | 2003-04-23 | 2014-11-12 | Stella Chemifa Corporation | Method for producing fluoride crystal |
| JP4902119B2 (en) * | 2005-01-12 | 2012-03-21 | デジタルパウダー株式会社 | Method for producing metal silicon particles |
| CN100357049C (en) * | 2005-09-29 | 2007-12-26 | 赫冀成 | Electromagnetic eddy flow downspout |
| DE102008037259A1 (en) * | 2008-08-08 | 2010-02-25 | Doncasters Precision Castings-Bochum Gmbh | Electromagnetic plug |
| RU2014138997A (en) | 2012-02-29 | 2016-04-20 | Эрастил Клостер Аб | METAL SPRAYING SYSTEM AND METAL POWDER SPRAYING METHOD |
| FR3044748B1 (en) * | 2015-12-03 | 2019-07-19 | Commissariat A L'energie Atomique Et Aux Energies Alternatives | COLD HOLLOW OVEN HEATED BY TWO ELECTROMAGNETIC INDUCERS, USE OF THE OVEN FOR THE FUSION OF A MIXTURE OF METAL (UX) AND OXIDE (S) REPRESENTATIVE OF A CORIUM |
| CN105945271B (en) * | 2016-07-06 | 2018-10-26 | 上海华培动力科技股份有限公司 | A kind of automatic controllable ration casting device and its pouring technology |
| CN106334799A (en) * | 2016-11-21 | 2017-01-18 | 张森 | Method for producing metal powder |
| CN106363188A (en) * | 2016-11-21 | 2017-02-01 | 张森 | Device for forming stable metal liquid flow |
| EP3363560A1 (en) * | 2017-02-20 | 2018-08-22 | ABB Schweiz AG | A method and stirring system for controlling an electromagnetic stirrer |
| WO2019246255A1 (en) * | 2018-06-20 | 2019-12-26 | Ultraflex International, Inc. | Melting and controlling the flow of molten metal by electromagnetic force utilizing multiple induction coils |
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| EP0021889A1 (en) * | 1979-05-31 | 1981-01-07 | ANVAR Agence Nationale de Valorisation de la Recherche | Process for confining molten metals by applying an electromagnetic field |
| EP0153205A1 (en) * | 1984-01-18 | 1985-08-28 | UNION SIDERURGIQUE DU NORD ET DE L'EST DE LA FRANCE par abréviation "USINOR" | Process and device for elaborating metallic and semi-metallic thin strip |
| US4572279A (en) * | 1984-02-27 | 1986-02-25 | Olin Corporation | Electromagnetic shaping of thin ribbon conductor strip cast onto a chill wheel |
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| FR2316026A1 (en) * | 1975-07-04 | 1977-01-28 | Anvar | ELECTROMAGNETIC DEVICE FOR CONTAINING LIQUID METALS |
| FR2396612A2 (en) * | 1977-07-08 | 1979-02-02 | Anvar | Electromagnetic device for controlling liq. metal flow - from a container by restricting the exit orifice |
| FR2397251A1 (en) * | 1977-07-12 | 1979-02-09 | Anvar | METHOD AND DEVICE FOR DIRECTING, IN THE ABSENCE OF WALLS, LIQUID METALLIC VEINS, IN PARTICULAR FOR CENTERING, GUIDING OR CHECKING THEIR CIRCULAR SHAPE |
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- 1989-07-12 FR FR8909369A patent/FR2649625B1/en not_active Expired - Fee Related
-
1990
- 1990-07-09 JP JP2181373A patent/JPH0645810B2/en not_active Expired - Lifetime
- 1990-07-10 US US07/550,491 patent/US5074532A/en not_active Expired - Lifetime
- 1990-07-12 EP EP90402006A patent/EP0408453B1/en not_active Expired - Lifetime
- 1990-07-12 DE DE9090402006T patent/DE69001217T2/en not_active Expired - Fee Related
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|---|---|---|---|---|
| EP0021889A1 (en) * | 1979-05-31 | 1981-01-07 | ANVAR Agence Nationale de Valorisation de la Recherche | Process for confining molten metals by applying an electromagnetic field |
| EP0153205A1 (en) * | 1984-01-18 | 1985-08-28 | UNION SIDERURGIQUE DU NORD ET DE L'EST DE LA FRANCE par abréviation "USINOR" | Process and device for elaborating metallic and semi-metallic thin strip |
| US4572279A (en) * | 1984-02-27 | 1986-02-25 | Olin Corporation | Electromagnetic shaping of thin ribbon conductor strip cast onto a chill wheel |
| EP0260617A1 (en) * | 1986-09-16 | 1988-03-23 | Centrem S.A. | Process and apparatus for preparing and finishing metallic materials |
| EP0345146A1 (en) * | 1988-05-30 | 1989-12-06 | Ugine S.A. | Inductor for an apparatus used in shaping liquid metal by electromagnetic forces |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0486830A2 (en) * | 1990-11-17 | 1992-05-27 | Eckart-Werke Standard Bronzepulver-Werke Carl Eckart Gmbh & Co. | Process for the atomisation of molten metal to produce metal powders |
| EP0486830A3 (en) * | 1990-11-17 | 1993-08-18 | Eckart-Werke Standard Bronzepulver-Werke Carl Eckart Gmbh & Co. | Process for the atomisation of molten metal to produce metal powders |
| EP0539051A1 (en) * | 1991-10-21 | 1993-04-28 | General Electric Company | Direct processing of electroslag refined metal |
| EP0549984A2 (en) * | 1991-12-20 | 1993-07-07 | National Research Institute For Metals | Levitating and fusing device |
| EP0549984A3 (en) * | 1991-12-20 | 1993-09-15 | National Research Institute For Metals | Levitating and fusing device |
| EP0636848A1 (en) * | 1993-07-29 | 1995-02-01 | Imphy S.A. | Smelting process of electrically-conductive materials in an induction smelting furnace with a cold crucible and furnace therefor |
| FR2708725A1 (en) * | 1993-07-29 | 1995-02-10 | Imphy Sa | Process for melting an electroconductive material in a melting furnace by induction in a cold crucible and melting furnace for the implementation of this process. |
| US5563904A (en) * | 1993-07-29 | 1996-10-08 | Tecphy | Process for melting an electroconductive material in a cold crucible induction melting furnace and melting furnace for carrying out the process |
Also Published As
| Publication number | Publication date |
|---|---|
| US5074532A (en) | 1991-12-24 |
| JPH0645810B2 (en) | 1994-06-15 |
| JPH03115508A (en) | 1991-05-16 |
| FR2649625B1 (en) | 1994-05-13 |
| DE69001217D1 (en) | 1993-05-06 |
| DE69001217T2 (en) | 1993-09-23 |
| FR2649625A1 (en) | 1991-01-18 |
| EP0408453B1 (en) | 1993-03-31 |
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