EP0275228B1 - Process and device for melting and continuously casting metals - Google Patents

Process and device for melting and continuously casting metals Download PDF

Info

Publication number
EP0275228B1
EP0275228B1 EP88420010A EP88420010A EP0275228B1 EP 0275228 B1 EP0275228 B1 EP 0275228B1 EP 88420010 A EP88420010 A EP 88420010A EP 88420010 A EP88420010 A EP 88420010A EP 0275228 B1 EP0275228 B1 EP 0275228B1
Authority
EP
European Patent Office
Prior art keywords
crucible
zone
metal
wall
sectorised
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP88420010A
Other languages
German (de)
French (fr)
Other versions
EP0275228A1 (en
Inventor
Marcel Garnier
Jean Driole
Annie Gagnoud
Patrick Paillère
Edouard Alhéritière
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Compagnie Europeenne du Zirconium Cezus SA
Original Assignee
Compagnie Europeenne du Zirconium Cezus SA
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Compagnie Europeenne du Zirconium Cezus SA filed Critical Compagnie Europeenne du Zirconium Cezus SA
Priority to AT88420010T priority Critical patent/ATE83597T1/en
Publication of EP0275228A1 publication Critical patent/EP0275228A1/en
Application granted granted Critical
Publication of EP0275228B1 publication Critical patent/EP0275228B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/10—Supplying or treating molten metal
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/22—Furnaces without an endless core
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/04—Continuous casting of metals, i.e. casting in indefinite lengths into open-ended moulds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D23/00—Casting processes not provided for in groups B22D1/00 - B22D21/00
    • B22D23/06—Melting-down metal, e.g. metal particles, in the mould

Definitions

  • the invention relates to a method and a vertical device for melting and continuous casting of metals, of the type called cold crucible with induction heating.
  • the cold crucible has a conductive wall, often of copper, consisting of several longitudinal sectors, in number ranging from 4 to more than 20, juxtaposed, electrically isolated from each other, and traversed by an internal circulation of coolant.
  • This wall is thus maintained at a temperature much lower than that of the melt.
  • the crucible is surrounded, over part of its height, by a cooled coaxial helical inductor, traversed by an alternating current at medium or high frequency.
  • the division into sectors of the wall of the crucible allows the alternating magnetic field of the inductor to induce in the metallic mass to be treated currents which heat it and stir it when it is melted.
  • the molten metal is evacuated progressively by an orifice, generally situated at the bottom of the crucible.
  • the device is then used exclusively for heating, solidification taking place in a separate ingot mold.
  • the contamination of the metal by the wall can be avoided by the formation of a film of solidified slag in contact with the wall, which constitutes a sheath around the liquid metal.
  • the metal is evacuated progressively in the solid state, by pulling down.
  • the metal is never in contact with the vertical cylindrical crucible, because on the one hand it is subjected to electromagnetic confinement forces, on the other hand a layer of solidified slag is interposed between the metal (liquid or solid) and the wall over the entire height of the appliance.
  • a layer of solidified slag is interposed between the metal (liquid or solid) and the wall over the entire height of the appliance.
  • the long contact length between the solid mass and the wall requires a great tensile force, and precautions to avoid tearing of material from the wall of the crucible; on the other hand, it is necessary to peel the layer of slag which adheres to the ingot before transforming it.
  • the slag is delicate to handle, constitutes a risk of metal pollution and corrosion of the crucible, requires additional oven cleaning operations, because it vaporizes when working under vacuum, and prevents the obtaining of an ingot shape. other than circular cylindrical.
  • FR-A-2303774 also discloses a device for melting and continuous casting of crystalline materials based on refractory metal oxides, this device comprising a cold conductive crucible with a vertical axis, the wall of which is formed on at least part of its height by longitudinal sectors electrically isolated from each other and traversed by a cooling fluid, an inductor with helical coils surrounding the crucible over part of its height and supplied with alternating current at medium or high frequency serving both to heating and confinement of the metal, and a system for drawing the ingot down.
  • Its crucible has generators extending downwards over its entire height so as to obtain continuous extraction of the crystalline material from a fusion bed, the unmelted part or lining of which is in contact with the cooled walls and protects the material from contact with these walls. No means of controlling the cross-sectional shape of the extracted material is described.
  • the invention which relates to a method and a corresponding device of the 2nd category above, makes it possible to remedy the drawbacks reported with regard to US-A-3775091 and to obtain a good quality ingot with respect to of a further transformation.
  • the first object of the invention is a method of melting and casting metals in which, according to US-A-3775091, a continuous crucible having a wall comprising longitudinal sectors electrically isolated from one another is continuously supplied with solid metal in divided form , said metal is induction melted by means of an inductor with helical coils surrounding the crucible, the metal thus molten is electromagnetically confined, it is cooled by circulating a coolant in said wall of the crucible, and said metal is extracted with l solidified state by pulling it down at a speed corresponding to said supply.
  • said wall of the crucible is divided into a sectored upper zone with vertical generators and into a sectorized zone with generators moving downwards situated in the lower position and connected to said upper zone, said inductor is placed so that its lowest turn is at the connection of said upper and lower zones, and said molten metal is electromagnetically confined so that this metal is in contact with said crucible wall, in the absence of slag, only over a limited height not exceeding 1 cm above said connection, facilitating the extraction of solidified metal and improving its surface condition.
  • the invention also relates to a melting and casting device, usable for implementing the above method, comprising according to FR-A-2303774 a cold conductive crucible with a vertical axis, the wall of which is formed on at least part of its height by longitudinal sectors electrically isolated from each other and traversed by a cooling fluid, an inductor with helical coils surrounding the crucible over part of its height and supplied with alternating current at medium or high frequency used both for heating and when confining the metal, a system for drawing the ingot downwards, said crucible comprising a sectorized lower zone with generators deviating downwards.
  • This device is characterized in that, being intended for the melting and continuous casting of metals, its said crucible comprises a sectored upper zone with vertical generators, in that this upper zone is connected to said sectored lower zone, and in that the the lowest turn of said inductor is at the level of the connection of said zones, said device thus making it possible to melt and flow without slag and to avoid tearing of metal on said wall of the crucible.
  • This structure allows, by means of the electrical adjustment of the inductor, to obtain the electromagnetic confinement of the liquid mass away of the wall, except in a portion of very low height, preferably not exceeding 1 cm, at the connection of the 2 zones of the crucible, where the side wall or skin of the metal is made to solidify in contact with the cold wall from the crucible. Below this level, the thickness of the solidified metal increases until it concerns the entire section of the ingot. Due to the change in cross section of the crucible passing from the upper zone to the lower zone, the solid metal only touches the wall at the low height indicated.
  • this contact zone is therefore limited to less than 1 cm, preferably 2 to 5 mm.
  • the level of the lowest coil of the inductor is very important. If it is located above the connection between the two zones of the crucible, it is not possible to limit the height of contact of the metal with the wall sufficiently, hence difficulties in the electrical field, and for drawing the ingot. On the other hand, if it is located below the connection, the risk of liquid metal running down the wall increases appreciably.
  • the reference level for the lowest turn of the inductor is that of the intersection of the extensions of these 2 zones.
  • the angle of inclination of the oblique generatrices of the lower zone of the crucible relative to the vertical generatrices of the upper sectorized wall of this crucible depends on the coefficient of contraction of the material on solidification. It must be chosen so that the ingot remains as close as possible to the wall so that it can continue to cool while avoiding touching it. An angle between 1 ° and 5 ° and preferably of the order of 2 ° is generally chosen.
  • the device contains as constant a quantity of metal as possible, the supply and extraction being precisely regulated.
  • the top of the dome of liquid metal (form due to electromagnetic confinement) is maintained at a constant level which depends on the electrical and magnetic characteristics of the system and the nature of the metal.
  • the height of the inductor is preferably chosen such that its upper turn is at the level of the top of the liquid dome. If the height of the inductor is smaller, there is an instability of the dome, with the risk of contact of the metal with the wall in unwanted areas. It is advantageous for the sectored upper zone of the crucible to exceed the top of the liquid dome by an amount of the order of 1/6 of the internal transverse dimension of the crucible.
  • the internal transverse dimension is half of the smallest dimension of the crucible. In the case of a circular section, it is the radius. In the case of an ellipse, it is the half minor axis. In the case of a square, it is the half side. In the case of a rectangle it is half width. Finally, in the case of a complex section, it is half the distance between the closest parallel segments or half the distance between the closest parallel tangent points.
  • the crucible can be extended upward by a non-sectored area. Then, the total height of the crucible above the highest turn of the inductor is at least equal to half of the interior transverse dimension of the crucible. The internal transverse dimension of the crucible is measured in the upper zone with vertical generators surrounded by the inductor.
  • the sectorized lower zone of the crucible has a total height at least equal to half the internal transverse dimension of the crucible to avoid a screen effect causing a drop in energy efficiency. Its wall is either entirely oblique or initially oblique and then extended downwards by a vertical portion.
  • the height of the oblique part is at least equal to a quarter of the internal transverse dimension of the crucible.
  • the crucible can also be extended downwards by a non-sectored zone with a vertical or oblique cooled wall connecting to the sectorized zone which is above it. Its height will preferably be between half the internal transverse dimension of the crucible and this dimension. Its role is above all to continue cooling the ingot.
  • the wall of the crucible is made of a material that is a good thermal and electrical conductor (for example, copper, aluminum) so as to have good energy efficiency.
  • the continuous slag-free casting according to the invention which requires a low metal-wall direct contact zone, requires a connection angle between the liquid and the wall corresponding to poor wetting. It is then necessary in certain cases to provide the internal surface of the crucible with a surface coating, for example metallic, or to subject it to a surface treatment, so as to obtain an excellent surface condition for the ingot.
  • the device of the invention is suitable for the production of cylindrical ingots. It is also suitable for the dairy-free preparation of ingots of non-circular cross-section, for example polygonal, the inner wall of the upper zone of the crucible then being of polygonal cylindrical shape, ingots which cannot be obtained in the presence of slag, because the solidification of this in the angles harms the good filling of the section with metal.
  • the inductors In order to obtain an effective value of the uniform magnetic field along the internal wall of the crucible, the inductors must be modified.
  • the distance between inductor and wall is varied in the vicinity of the angles to reduce the intensity of the field.
  • the magnetic circuit is arranged in the rectilinear parts of the crucible section, for example by partially surrounding the inductor with magnetic sheets or ferrites, possibly cooled, to increase the field in these areas.
  • the device of the invention particularly advantageous for the remelting and casting of refractory metals of groups IV, V and VI or their alloys, is also usable for the remelting and casting of other metals or alloys, in particular earth rare, aluminum, copper, silicon and nickel or cobalt base alloys. It is also suitable for the production of metal by chemical reaction, in particular when the other product formed by this reaction is gaseous or volatile.
  • Figures 1a and 1b show the schematic transverse and axial sections of a cold crucible according to the invention.
  • FIG. 2 represents a semi-continuous melting and casting installation according to the invention in a controlled atmosphere.
  • Figures 3 and 4 show cross-sectional diagrams of polygonal crucibles with suitable inductors.
  • FIG. 1b the electrical and fluid connections have not been shown.
  • 1 is a copper crucible with a circular section 180 mm high.
  • the upper 125 mm (a + b + c) consist of 16 hollow sectors 2 which are each of substantially trapezoidal cross section (Figure 1a), cooled by internal circulation of water, the lower 55 mm (d) being constituted by a skirt 3 also cooled by internal circulation of water ( Figure 1b).
  • the upper zone 4 of the crucible 1 is in the form of a cylinder 80 mm high and 60 mm in internal diameter.
  • the inductor 6 is a copper tube 1 mm thick and 6 mm in internal diameter, wound helically over a height of 7 substantially contiguous and isolated turns, with a diameter of 85 mm. 7 is the false bottom of the cylindrical part of the crucible, on which the solidified metal 8 of the ingot rests and which is drawn downwards in steady state.
  • Titanium shavings are purified by reflow.
  • the titanium false back is in position such that its upper face is located at mid-height of the inductor.
  • the electric power is gradually increased until the upper part of the false bottom melts.
  • the false bottom is pulled slightly, titanium shavings are fed and the power is further increased to its nominal value.
  • FIG 2 shows the semi-continuous casting installation used.
  • the crucible 20 is placed inside the sealed enclosure 21 under argon at atmospheric pressure.
  • the means for introducing inert gas or for placing under vacuum are not shown.
  • the hopper 22 contains the material which is fed into the crucible via the distributor 23.
  • the false bottom 7 which supports the ingot 25 is linked to the rod 26 which is driven by the device 27 and which passes tightly through the wall of the enclosure 21.
  • the operation of the supply and extraction devices are synchronized by means of a regulator not shown, controlled by laser measurement of the level of the dome of liquid metal in the crucible.
  • a crucible was produced having substantially the same dimensions as that of Example 1, with only 2 differences: the angle of the cone was 2.5 ° and the height of the lower conical skirt not sectored was 70 mm.
  • the operating power is 35 kW at the terminals of the inductor, with a frequency current of 9 kHz.
  • a copper crucible with 16 sectors was produced, with an internal diameter of 100 mm, with a total height of 280 mm.
  • the sectors extend over a height of 230 mm from the top.
  • the upper part is cylindrical and 130 mm high, the lower part is tapered with an angle of 2 ° and with a sectored height of 100 mm.
  • the inductor with 10 turns in tube of outside diameter 8 mm, and thickness 1 mm, has a height of 85 mm and an inside diameter of 150 mm.
  • the metal / wall contact height remains between 5 and 10 mm. In 75 min, a 35 kg ingot is obtained.
  • the corresponding internal transverse dimension 1/2 is 9 mm.
  • Its total height is 110 mm. It comprises, from top to bottom, a sectorized cylindrical part of 65 mm in height, a sectorized conical part of 15 mm and a non-sectorized conical part of 30 mm.
  • the angle of the cone is 2 °.
  • the number of sectors is 18.
  • the inductor 106 with 6 turns has a height of 50 mm. It is made of the same copper tube as in the previous examples.
  • the space between crucible and inductor is 10 mm, except in the vicinity of the angles where it is increased.
  • This figure represents a variant of Example 4, where the inductor 206 of substantially constant spacing with the sectors of the crucible 200, is surrounded by magnetic sheets 2060 on its rectilinear parts, so as to increase the field in the corresponding zones.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Crucibles And Fluidized-Bed Furnaces (AREA)
  • Continuous Casting (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
  • Dental Prosthetics (AREA)
  • Manufacture Of Alloys Or Alloy Compounds (AREA)
  • Furnace Details (AREA)
  • Control Of Vending Devices And Auxiliary Devices For Vending Devices (AREA)

Abstract

Apparatus for melting and continuously casting metals, comprising a vertical, conductive cold crucible (1) with at least part of the height of its wall in the form of longitudinal sectors (2) which are electrically insulated from one another and have a cooling fluid running through them; an inductor (6) with coils helically surrounding the crucible (1) over part of its height and supplied with alternating current both for heating and confining the metal; a system for drawing down the ingot; and possibly a chamber with a controlled external atmosphere, separating at least the contents of the crucible (1) from the external atmosphere, characterized in that the crucible (1) has an upper zone (4) divided into sectors, with parallel vertical generating lines, and a lower zone (5) divided into sectors and joined to the upper zone (4), the generating lines of the lower zone spreading apart in a downward direction from the join (45) between the two zones (4 and (5), and that the lowest coil (60) of the inductor (6) is at the level of that join (45). The apparatus of the invention is advantageously used for melting and casting refractory metals and other materials.

Description

L'invention concerne un procédé et un dispositif vertical de fusion et coulée continue de métaux, du type appelé à creuset froid à chauffage par induction.The invention relates to a method and a vertical device for melting and continuous casting of metals, of the type called cold crucible with induction heating.

Le creuset froid a une paroi conductrice, souvent de cuivre, constituée de plusieurs secteurs longitudinaux, en nombre allant de 4 à plus de 20, juxtaposés, isolés électriquement les uns des autres, et parcourus par une circulation interne de fluide réfrigérant.The cold crucible has a conductive wall, often of copper, consisting of several longitudinal sectors, in number ranging from 4 to more than 20, juxtaposed, electrically isolated from each other, and traversed by an internal circulation of coolant.

Cette paroi est ainsi maintenue à une température beaucoup plus basse que celle de la masse fondue.This wall is thus maintained at a temperature much lower than that of the melt.

Le creuset est entouré, sur une partie de sa hauteur, par un inducteur hélicoïdal coaxial refroidi, parcouru par un courant alternatif à moyenne ou haute fréquence. La division en secteurs de la paroi du creuset permet au champ magnétique alternatif de l'inducteur d'induire dans la masse métallique à traiter des courants qui la chauffent et la brassent lorsqu'elle est fondue.The crucible is surrounded, over part of its height, by a cooled coaxial helical inductor, traversed by an alternating current at medium or high frequency. The division into sectors of the wall of the crucible allows the alternating magnetic field of the inductor to induce in the metallic mass to be treated currents which heat it and stir it when it is melted.

Dans une première catégorie d'appareils de coulée continue à creuset foid, le métal fondu est évacué au fur et à mesure par un orifice, situé en général au fond du creuset. L'appareil sert alors exclusivement au chauffage, la solidification ayant lieu dans une lingotière séparée. La contamination du métal par la paroi peut être évitée par la formation d'une pellicule de laitier solidifié au contact de la paroi, qui constitue une gaine autour du métal liquide.In a first category of continuous casting apparatus with cold crucible, the molten metal is evacuated progressively by an orifice, generally situated at the bottom of the crucible. The device is then used exclusively for heating, solidification taking place in a separate ingot mold. The contamination of the metal by the wall can be avoided by the formation of a film of solidified slag in contact with the wall, which constitutes a sheath around the liquid metal.

Une autre solution est le confinement électromagnétique à l'aide d'un champ magnétique alternatif qui développe des forces faisant décoller de la paroi la surface latérale de la masse fondue. Ces deux méthodes sont évoquées dans le brevet FR-A-2497050 (=US-A-4432093).Another solution is electromagnetic confinement using an alternating magnetic field which develops forces causing the lateral surface of the melt to peel off from the wall. These two methods are mentioned in patent FR-A-2497050 (= US-A-4432093).

Dans une deuxième catégorie d'appareils de coulée continue à creuset froid, le métal est évacué au fur et à mesure à l'état solide, par tirage vers le bas.In a second category of cold crucible continuous casting devices, the metal is evacuated progressively in the solid state, by pulling down.

L'appareil assure alors le chauffage (fusion) de la charge, son refroidissement (solidification) et son extraction. C'est le cas du brevet US-A-3775091.
Ce brevet décrit un procédé de fusion et de coulée de métaux, dans lequel on alimente en continu en métal solide sous forme divisée un creuset ayant une paroi comprenant des secteurs longitudinaux isolés électriquement les uns des autres, on fond par induction ledit métal au moyen d'un inducteur à spires hélicoïdales entourant le creuset, on confine électromagnétiquement le métal ainsi fondu, on le refroidit en faisant circuler un fluide réfrigérant dans ladite paroi du creuset, et on extrait ledit métal à l'état solidifié en le tirant vers le bas à une vitesse correspondant à ladite alimentation.
Le métal n'est jamais au contact du creuset cylindrique vertical, car d'une part il est soumis à des forces de confinement électromagnétiques, d'autre part une couche de laitier solidifié est interposée entre le métal (liquide ou solide) et la paroi sur toute la hauteur de l'appareil. Il y a ici plusieurs inconvénients : d'une part, la grande longueur de contact entre la masse solide et la paroi exige une grande force de traction, et des précautions pour éviter l'arrachement de matière sur la paroi du creuset ; d'aute part, il faut écroûter la couche de laitier qui adhère au lingot avant de transformer celui-ci. Enfin, le laitier est délicat à manipuler, constitue un risque de pollution du métal et de corrosion du creuset, impose des opérations supplémentaires de nettoyage de four, car il se vaporise quand on travaille sous vide, et empêche l'obtention de forme de lingot autre que cylindrique circulaire.The device then ensures the heating (melting) of the load, its cooling (solidification) and its extraction. This is the case of patent US-A-3775091.
This patent describes a method of melting and casting metals, in which a solid metal is continuously supplied in divided form to a crucible having a wall comprising longitudinal sectors electrically isolated from each other, said metal is melted by induction by means of an inductor with helical coils surrounding the crucible, the molten metal is electromagnetically confined, it is cooled by circulating a coolant in said wall of the crucible, and said metal is extracted in the solidified state by pulling it downwards to a speed corresponding to said supply.
The metal is never in contact with the vertical cylindrical crucible, because on the one hand it is subjected to electromagnetic confinement forces, on the other hand a layer of solidified slag is interposed between the metal (liquid or solid) and the wall over the entire height of the appliance. There are several drawbacks here: on the one hand, the long contact length between the solid mass and the wall requires a great tensile force, and precautions to avoid tearing of material from the wall of the crucible; on the other hand, it is necessary to peel the layer of slag which adheres to the ingot before transforming it. Finally, the slag is delicate to handle, constitutes a risk of metal pollution and corrosion of the crucible, requires additional oven cleaning operations, because it vaporizes when working under vacuum, and prevents the obtaining of an ingot shape. other than circular cylindrical.

On connaît par ailleurs par FR-A-2303774 un dispositif de fusion et de coulée continue de matériaux cristallins à base d'oxydes réfractaires de métaux, ce dispositif comportant un creuset froid conducteur à axe vertical dont la paroi est constituée sur au moins une partie de sa hauteur par des secteurs longitudinaux isolés électriquement les uns des autres et parcourus par un fluide de refroidissement, un inducteur à spires hélicoïdales entourant le creuset sur une partie de sa hauteur et alimenté en courant alternatif à moyenne ou haute fréquence servant à la fois au chauffage et au confinement du métal, et un système de tirage du lingot vers le bas.
Son creuset a sur toute sa hauteur des génératrices s'écartant vers le bas de façon à obtenir l'extraction continue du matériau cristallin à partir d'un lit de fusioni, dont la partie non fondue ou garnissage est en contact avec les parois refroidies et protège le matériau de tout contact avec ces parois. Il n'est pas décrit de moyen de contrôler la forme en section droite du matériau extrait.FR-A-2303774 also discloses a device for melting and continuous casting of crystalline materials based on refractory metal oxides, this device comprising a cold conductive crucible with a vertical axis, the wall of which is formed on at least part of its height by longitudinal sectors electrically isolated from each other and traversed by a cooling fluid, an inductor with helical coils surrounding the crucible over part of its height and supplied with alternating current at medium or high frequency serving both to heating and confinement of the metal, and a system for drawing the ingot down.
Its crucible has generators extending downwards over its entire height so as to obtain continuous extraction of the crystalline material from a fusion bed, the unmelted part or lining of which is in contact with the cooled walls and protects the material from contact with these walls. No means of controlling the cross-sectional shape of the extracted material is described.

L'invention, qui se rapporte à un procédé et un dispositif correspondant de la 2ème catégorie ci-dessus, permet de remédier aux inconvénients signalés au sujet de US-A-3775091 et d'obtenir un lingot de bonne qualité vis-à-vis d'une transformation ultérieure.The invention, which relates to a method and a corresponding device of the 2nd category above, makes it possible to remedy the drawbacks reported with regard to US-A-3775091 and to obtain a good quality ingot with respect to of a further transformation.

L'invention a pour premier objet un procédé de fusion et coulée de métaux dans lequel, selon US-A-3775091, on alimente en continu en métal solide sous forme divisée un creuset ayant une paroi comprenant des secteurs longitudinaux isolés électriquement les uns des autres, on fond par induction ledit métal au moyen d'un inducteur à spires hélicoïdales entourant le creuset, on confine électromagnétiquement le métal ainsi fondu, on le refroidit en faisant circuler un fluide réfrigérant dans ladite paroi du creuset, et on extrait ledit métal à l'état solidifié en le tirant vers le bas à une vitesse correspondant à ladite alimentation.The first object of the invention is a method of melting and casting metals in which, according to US-A-3775091, a continuous crucible having a wall comprising longitudinal sectors electrically isolated from one another is continuously supplied with solid metal in divided form , said metal is induction melted by means of an inductor with helical coils surrounding the crucible, the metal thus molten is electromagnetically confined, it is cooled by circulating a coolant in said wall of the crucible, and said metal is extracted with l solidified state by pulling it down at a speed corresponding to said supply.

Selon l'invention, on divise ladite paroi du creuset en une zone supérieure sectorisée à génératrices verticales et en une zone sectorisée à génératrices s'écartant vers le bas située en position inférieure et raccordée à ladite zone supérieure, on place ledit inducteur de sorte que sa spire la plus basse soit au niveau du raccordement desdites zones supérieures et inférieures, et on confine électromagnétiquement ledit métal fondu de manière que ce métal soit en contact avec ladite paroi du creuset, en l'absence de laitier, seulement sur une hauteur limitée ne dépassant pas 1 cm au-dessus dudit raccordement, facilitant l'extraction du métal solidifié et améliorant sont état de surface.According to the invention, said wall of the crucible is divided into a sectored upper zone with vertical generators and into a sectorized zone with generators moving downwards situated in the lower position and connected to said upper zone, said inductor is placed so that its lowest turn is at the connection of said upper and lower zones, and said molten metal is electromagnetically confined so that this metal is in contact with said crucible wall, in the absence of slag, only over a limited height not exceeding 1 cm above said connection, facilitating the extraction of solidified metal and improving its surface condition.

Des particularités de ce procédé apparaîtront dans la suite de la description.Special features of this process will appear in the following description.

L'invention a aussi pour objet un dispositif de fusion et de coulée, utilisable pour la mise en oeuvre du procédé précédent, comportant selon FR-A-2303774 un creuset froid conducteur à axe vertical dont la paroi est constituée sur au moins une partie de sa hauteur par des secteurs longitudinaux isolés électriquement les uns des autres et parcourus par un fluide de refroidissement, un inducteur à spires hélicoïdales entourant le creuset sur une partie de sa hauteur et alimenté en courant alternatif à moyenne ou haute fréquence servant à la fois au chauffage et au confinement du métal, un système de tirage du lingot vers le bas, ledit creuset comportant une zone inférieure sectorisée à génératrices s'écartant vers le bas.The invention also relates to a melting and casting device, usable for implementing the above method, comprising according to FR-A-2303774 a cold conductive crucible with a vertical axis, the wall of which is formed on at least part of its height by longitudinal sectors electrically isolated from each other and traversed by a cooling fluid, an inductor with helical coils surrounding the crucible over part of its height and supplied with alternating current at medium or high frequency used both for heating and when confining the metal, a system for drawing the ingot downwards, said crucible comprising a sectorized lower zone with generators deviating downwards.

Ce dispositif est caractérisé en ce que, étant destiné à la fusion et coulée continue de métaux, son dit creuset comporte une zone supérieure sectorisée à génératrices verticales, en ce que cette zone supérieure se raccorde à ladite zone inférieure sectorisée, et en ce que la spire la plus basse dudit inducteur est au niveau du raccordement desdites zones, ledit dispositif permettant ainsi de fondre et couler sans laitier et d'éviter les arrachements de métal sur ladite paroi du creuset.This device is characterized in that, being intended for the melting and continuous casting of metals, its said crucible comprises a sectored upper zone with vertical generators, in that this upper zone is connected to said sectored lower zone, and in that the the lowest turn of said inductor is at the level of the connection of said zones, said device thus making it possible to melt and flow without slag and to avoid tearing of metal on said wall of the crucible.

Cette structure permet, moyennant le régalge électrique de l'inducteur, d'obtenir le confinement électromagnétique de la masse liquide à l'écart de la paroi, sauf dans une portion de hauteur très faible, de préférence ne dépassant pas 1 cm, au niveau du raccordement des 2 zones du creuset, où l'on fait solidifier la paroi latérale ou peau du métal au contact de la paroi froide du creuset.
Au-dessous de ce niveau, l'épaisseur du métal solidifié augmente jusqu'à intéresser toute la section du lingot.
Du fait du changement de section du creuset en passant de la zone supérieure à la zone inférieure, le métal solide ne touche la paroi que sur la faible hauteur indiquée.
De cette façon le tirage du lingot est facilité, la pollution du métal solidifié par le métal du creuset est inexistante, le risque d'arrachement de métal à ladite paroi quasiment nul et le lingot a donc un bon état de surface.
Ce dispositif permet de fonctionner sans laitier, d'où simplification du système d'alimentation, possibilité de travailler facilement sous vide ou sous atmosphère inerte et suppression de l'opération d'écroûtage avant travail du lingot.
Il est nécessaire pour un fonctionnement correct du dispositif, qu'il existe une zone de contact métal-paroi pour former la peau du lingot.This structure allows, by means of the electrical adjustment of the inductor, to obtain the electromagnetic confinement of the liquid mass away of the wall, except in a portion of very low height, preferably not exceeding 1 cm, at the connection of the 2 zones of the crucible, where the side wall or skin of the metal is made to solidify in contact with the cold wall from the crucible.
Below this level, the thickness of the solidified metal increases until it concerns the entire section of the ingot.
Due to the change in cross section of the crucible passing from the upper zone to the lower zone, the solid metal only touches the wall at the low height indicated.
In this way the drawing of the ingot is facilitated, the pollution of the solidified metal by the metal of the crucible is nonexistent, the risk of tearing of metal from said wall almost zero and the ingot therefore has a good surface condition.
This device makes it possible to operate without slag, hence the simplification of the feeding system, possibility of working easily under vacuum or under inert atmosphere and elimination of the peeling operation before ingot working.
It is necessary for correct operation of the device, that there is a metal-wall contact zone to form the skin of the ingot.

On a constaté avec surprise que, tant que la hauteur de cette zone de contact restait faible, le contact électrique que le métal produit entre les secteurs du creuset ne perturbe pas le fonctionnement électrique du système. Aussi limite-t-on la hauteur de cette zone à moins de 1 cm, de préférence à 2 à 5 mm.
Le niveau de la spire la plus basse de l'inducteur est très important. S'il se situe au-dessus du raccordement entre les deux zones du creuset, on ne peut pas limiter suffisamment la hauteur de contact du métal avec la paroi, d'où des difficultés dans le domaine électrique, et pour le tirage du lingot. Par contre, s'il se situe au-dessous du raccordement, le risque des coulures de métal liquide le long de la paroi augmente sensiblement.It has been surprisingly found that, as long as the height of this contact zone remains low, the electrical contact that the metal produced between the sectors of the crucible does not disturb the electrical operation of the system. The height of this zone is therefore limited to less than 1 cm, preferably 2 to 5 mm.
The level of the lowest coil of the inductor is very important. If it is located above the connection between the two zones of the crucible, it is not possible to limit the height of contact of the metal with the wall sufficiently, hence difficulties in the electrical field, and for drawing the ingot. On the other hand, if it is located below the connection, the risk of liquid metal running down the wall increases appreciably.

Lorsqu'on prévoit une zone courbe assez courte de raccordement entre partie cylindrique et partie conique du creuset, le niveau de référence pour la spire la plus basse de l'inducteur est celui de l'intersection des prolongements de ces 2 zones.When a fairly short curved zone of connection between the cylindrical part and the conical part of the crucible is provided, the reference level for the lowest turn of the inductor is that of the intersection of the extensions of these 2 zones.

L'angle d'inclinaison des génératrices obliques de la zone inférieure du creuset par rapport aux génératrices verticales de la paroi supérieure sectorisée de ce creuset dépend du coefficient de contraction du matériau à la solidification. Il doit être choisi de façon que le lingot reste le plus proche possible de la paroi pour qu'il puisse poursuivre son refroidissement tout en évitant de la toucher.
Un angle compris entre 1° et 5° et de préférence de l'ordre de 2° est en général choisi.The angle of inclination of the oblique generatrices of the lower zone of the crucible relative to the vertical generatrices of the upper sectorized wall of this crucible depends on the coefficient of contraction of the material on solidification. It must be chosen so that the ingot remains as close as possible to the wall so that it can continue to cool while avoiding touching it.
An angle between 1 ° and 5 ° and preferably of the order of 2 ° is generally chosen.

En régime de fonctionnement établi, l'appareil contient une quantité de métal aussi constante que possible, l'alimentation et l'extraction faisant l'objet d'une régulation précise. Le sommet du dôme de métal liquide (forme due au confinement électromagnétique) est maintenu à un niveau constant qui dépend des caractéristiques électriques et magnétiques du système et de la nature du métal.
On choisit de préférence une hauteur de l'inducteur telle que sa spire supérieure soit au niveau du sommet du dôme liquide. Si la hauteur de l'inducteur est plus petite, on a une instabilité du dôme, avec risque de contact du métal avec la paroi en des zones non désirées.
Il est avantageux que la zone supérieure sectorisée du creuset dépasse le sommet du dôme liquide d'une quantité de l'ordre de 1/6 de la dimension transversale intérieure du creuset.In established operating conditions, the device contains as constant a quantity of metal as possible, the supply and extraction being precisely regulated. The top of the dome of liquid metal (form due to electromagnetic confinement) is maintained at a constant level which depends on the electrical and magnetic characteristics of the system and the nature of the metal.
The height of the inductor is preferably chosen such that its upper turn is at the level of the top of the liquid dome. If the height of the inductor is smaller, there is an instability of the dome, with the risk of contact of the metal with the wall in unwanted areas.
It is advantageous for the sectored upper zone of the crucible to exceed the top of the liquid dome by an amount of the order of 1/6 of the internal transverse dimension of the crucible.

La dimension transversale intérieure est la moitié de la plus petite dimension du creuset. Dans le cas d'une section circulaire, c'est le rayon. Dans le cas d'une ellipse, c'est le demi petit axe. Dans le cas d'un carré, c'est le demi côté. Dans le cas d'un rectangle c'est la demi largeur. Enfin, dans le cas d'une section complexe, c'est la moitié de la distance entre les segments parallèles les plus rapprochés ou la moitié de la distance entre les points à tangentes parallèles les plus rapprochés.The internal transverse dimension is half of the smallest dimension of the crucible. In the case of a circular section, it is the radius. In the case of an ellipse, it is the half minor axis. In the case of a square, it is the half side. In the case of a rectangle it is half width. Finally, in the case of a complex section, it is half the distance between the closest parallel segments or half the distance between the closest parallel tangent points.

Dans une variante, le creuset peut être prolongé vers le haut par une zone non sectorisée. Alors, la hauteur totale du creuset au-dessus de la spire la plus haute de l'inducteur est au moins égale à la moitié de la dimension transversale intérieure du creuset.
La dimension transversale intérieure du creuset est mesurée dans la zone supérieure à génératrices verticales entourée par l'inducteur.Alternatively, the crucible can be extended upward by a non-sectored area. Then, the total height of the crucible above the highest turn of the inductor is at least equal to half of the interior transverse dimension of the crucible.
The internal transverse dimension of the crucible is measured in the upper zone with vertical generators surrounded by the inductor.

La zone inférieure sectorisée du creuset a une hauteur totale au moins égale à la moitié de la dimension transversale intérieure du creuset pour éviter un effet d'écran provoquant une baisse de rendement énergétique.
Sa paroi est, soit entièrement oblique, soit d'abord oblique puis prolongée vers le bas par une portion verticale.The sectorized lower zone of the crucible has a total height at least equal to half the internal transverse dimension of the crucible to avoid a screen effect causing a drop in energy efficiency.
Its wall is either entirely oblique or initially oblique and then extended downwards by a vertical portion.

Dans ce dernier cas, la hauteur de la partie oblique est au moins égale au quart de la dimension transversale intérieure du creuset. On peut encore prolonger le creuset vers le bas par une zone non sectorisée à paroi refroidie verticale ou oblique se raccordant à la zone sectorisée qui est au-dessus d'elle.
Sa hauteur sera de préférence comprise entre la moitié de la dimension transversale intérieure du creuset et cette dimension. Son rôle est surtout de poursuivre le refroidissement du lingot.In the latter case, the height of the oblique part is at least equal to a quarter of the internal transverse dimension of the crucible. The crucible can also be extended downwards by a non-sectored zone with a vertical or oblique cooled wall connecting to the sectorized zone which is above it.
Its height will preferably be between half the internal transverse dimension of the crucible and this dimension. Its role is above all to continue cooling the ingot.

La paroi du creuset est réalisée en matériau bon conducteur thermique et électrique (par exemple, cuivre, aluminium) de façon à avoir un bon rendement énergétique.The wall of the crucible is made of a material that is a good thermal and electrical conductor (for example, copper, aluminum) so as to have good energy efficiency.

La coulée continue sans laitier selon l'invention, qui nécessite une zone de contact direct métal-paroi de hauteur faible, demande un angle de raccordement entre le liquide et la paroi correspondant à un mauvais mouillage. On est alors amené dans certains cas à munir la surface interne du creuset d'un revêtement superficiel, par exemple métallique, ou à lui faire subir un traitement de surface, de façon à obtenir un excellent état de surface pour le lingot.The continuous slag-free casting according to the invention, which requires a low metal-wall direct contact zone, requires a connection angle between the liquid and the wall corresponding to poor wetting. It is then necessary in certain cases to provide the internal surface of the crucible with a surface coating, for example metallic, or to subject it to a surface treatment, so as to obtain an excellent surface condition for the ingot.

Le dispositif de l'invention convient pour l'élaboration de lingots cylindriques. Il convient aussi pour l'élaboration sans laitier de lingots de section non circulaire, par exemple polygonale, la paroi intérieure de la zone supérieure du creuset étant alors de forme cylindrique polygonale, lingots que l'on ne peut pas obtenir en présence de laitier, car la solidification de celuici dans les angles nuit au bon remplissage de la section par le métal.The device of the invention is suitable for the production of cylindrical ingots. It is also suitable for the dairy-free preparation of ingots of non-circular cross-section, for example polygonal, the inner wall of the upper zone of the crucible then being of polygonal cylindrical shape, ingots which cannot be obtained in the presence of slag, because the solidification of this in the angles harms the good filling of the section with metal.

Pour obtenir alors une valeur efficace du champ magnétique uniforme le long de la paroi interne du creuset, il faut modifier les inducteurs.
Dans un premier mode de réalisation (fig. 3), on fait varier la distance entre inducteur et paroi au voisinage des angles pour y réduire l'intensité du champ.
Dans un second mode de réalisation (fig. 4), on aménage le circuit magnétique dans les parties rectilignes de la section du creuset, par exemple en entourant partiellement l'inducteur de tôles magnétiques ou de ferrites, éventuellement refroidies, pour augmenter le champ dans ces zones.In order to obtain an effective value of the uniform magnetic field along the internal wall of the crucible, the inductors must be modified.
In a first embodiment (fig. 3), the distance between inductor and wall is varied in the vicinity of the angles to reduce the intensity of the field.
In a second embodiment (fig. 4), the magnetic circuit is arranged in the rectilinear parts of the crucible section, for example by partially surrounding the inductor with magnetic sheets or ferrites, possibly cooled, to increase the field in these areas.

Le dispositif de l'invention, particulièrement avantageux pour la refusion et la coulée de métaux réfractaires des groupes IV, V et VI ou de leurs alliages, est aussi utilisable pour la refusion et la coulée d'autres métaux ou alliages, en particulier les terres rares, l'aluminium, le cuivre, le silicium et les alliages bases nickel ou cobalt. Il convient en outre à la production de métal par réaction chimique, en particulier lorsque l'autre produit formé par cette réaction est gazeux ou volatil.The device of the invention, particularly advantageous for the remelting and casting of refractory metals of groups IV, V and VI or their alloys, is also usable for the remelting and casting of other metals or alloys, in particular earth rare, aluminum, copper, silicon and nickel or cobalt base alloys. It is also suitable for the production of metal by chemical reaction, in particular when the other product formed by this reaction is gaseous or volatile.

Les figures 1a et 1b représentent les coupes schématiques transversale et axiale d'un creuset froid selon l'invention.Figures 1a and 1b show the schematic transverse and axial sections of a cold crucible according to the invention.

La figure 2 représente une installation de fusion et coulée semi-continue, selon l'invention en atmosphère contrôlée.FIG. 2 represents a semi-continuous melting and casting installation according to the invention in a controlled atmosphere.

Les figures 3 et 4 représentent des schémas en coupe transversale de creusets polygonaux avec les inducteurs adaptés.Figures 3 and 4 show cross-sectional diagrams of polygonal crucibles with suitable inductors.

EXEMPLE 1EXAMPLE 1

Sur la figure 1b, les connexions électriques et de fluide n'ont pas été représentées.
1 est un creuset en cuivre à section circulaire de 180 mm de haut.
Les 125 mm supérieurs (a+b+c) sont constitués par 16 secteurs creux 2 qui sont chacun de section droite sensiblement trapézoïdale (figure 1a), refroidis par circulation interne d'eau, les 55 mm inférieurs (d) étant constitués par une jupe 3 refroidie aussi par circulation interne d'eau (figure 1b).
La zone supérieure 4 du creuset 1 est en forme de cylindre de 80 mm de haut et 60 mm de diamètre intérieur.
La zone inférieure 5 est en forme de tronc de cône de 100 mm de haut et d'angle au sommet 4°, sectorisée sur une hauteur c = 45 mm, le reste de la hauteur d = 55 mm n'étant pas sectorisée.
L'inducteur 6 est un tube de cuivre de 1 mm d'épaisseur et de 6 mm de diamètre intérieur, enroulé en hélice sur une hauteur de 7 spires sensiblement jointives et isolées, d'un diamètre de 85 mm.
7 est le faux-fond de la partie cylindrique du creuset, sur lequel repose le métal solidifié 8 du lingot et que l'on tire vers le bas en régime permanent.In Figure 1b, the electrical and fluid connections have not been shown.
1 is a copper crucible with a circular section 180 mm high.
The upper 125 mm (a + b + c) consist of 16 hollow sectors 2 which are each of substantially trapezoidal cross section (Figure 1a), cooled by internal circulation of water, the lower 55 mm (d) being constituted by a skirt 3 also cooled by internal circulation of water (Figure 1b).
The upper zone 4 of the crucible 1 is in the form of a cylinder 80 mm high and 60 mm in internal diameter.
The lower zone 5 is in the form of a truncated cone 100 mm high and at an angle at the top 4 °, sectorized over a height c = 45 mm, the rest of the height d = 55 mm not being sectorized.
The inductor 6 is a copper tube 1 mm thick and 6 mm in internal diameter, wound helically over a height of 7 substantially contiguous and isolated turns, with a diameter of 85 mm.
7 is the false bottom of the cylindrical part of the crucible, on which the solidified metal 8 of the ingot rests and which is drawn downwards in steady state.

L'ensemble est dans une enceinte isolée sous argon à la pression atmosphérique. On y purifie des copeaux de titane par refusion. Au démarrage le fauxfond en titane est en position telle que sa face supérieure se situe à mihauteur de l'inducteur.
La puissance électrique est augmentée progressivement jusqu'à fusion de la partie supérieure du faux-fond. Le faux-fond est tiré légèrement, on alimente des copeaux de titane et on augmente encore la puissance jusqu'à sa valeur nominale.The whole is in an enclosure isolated under argon at atmospheric pressure. Titanium shavings are purified by reflow. At start-up, the titanium false back is in position such that its upper face is located at mid-height of the inductor.
The electric power is gradually increased until the upper part of the false bottom melts. The false bottom is pulled slightly, titanium shavings are fed and the power is further increased to its nominal value.

Lorsque le sommet 9 du dôme liquide 10 arrive au niveau du haut 11 de l'inducteur 6, on alimente au débit de fonctionnement normal, soit 200 g/min de copeaux de titane, et on tire le faux-fond 7 à raison de 1,6 cm/min. Pendant toute l'opération la hauteur de contact métal-paroi est restée comprise entre 2 et 5 mm. En 32 min on a obtenu un lingot de 6,5 kg ayant la composition suivante :

O₂
2000 ppm
C
230 ppm
N₂
105 ppm
Cu
< 20 ppm
Ti
reste
et un excellent état de surface.When the top 9 of the liquid dome 10 arrives at the top 11 of the inductor 6, it is supplied at the normal operating rate, ie 200 g / min of titanium shavings, and the false bottom 7 is drawn at the rate of 1 , 6 cm / min. During the whole operation, the metal-wall contact height remained between 2 and 5 mm. In 32 min, a 6.5 kg ingot was obtained having the following composition:
Where
2000 ppm
VS
230 ppm
No.
105 ppm
Cu
<20 ppm
Ti
rest
and an excellent surface finish.

La figure 2 représente l'installation de coulée semi-continue utlisée. Le creuset 20 est placé à l'intérieur de l'enceinte étanche 21 sous argon à la pression atmosphérique. Les moyens d'introduction de gaz inerte ou de mise sous vide ne sont pas représentés. La trémie 22 contient le matériau qui est alimenté dans le creuset par l'intermédiaire du distributeur 23. Le faux-fond 7 qui supporte le lingot 25 est lié à la tige 26 qui est entraînée par le dispositif 27 et qui traverse de façon étanche la paroi de l'enceinte 21. Le fonctionnement des dispositifs d'alimentation et d'extraction sont synchronisés grâce à un régulateur non représenté, commandé par la mesure par laser du niveau du dôme de métal liquide dans le creuset.Figure 2 shows the semi-continuous casting installation used. The crucible 20 is placed inside the sealed enclosure 21 under argon at atmospheric pressure. The means for introducing inert gas or for placing under vacuum are not shown. The hopper 22 contains the material which is fed into the crucible via the distributor 23. The false bottom 7 which supports the ingot 25 is linked to the rod 26 which is driven by the device 27 and which passes tightly through the wall of the enclosure 21. The operation of the supply and extraction devices are synchronized by means of a regulator not shown, controlled by laser measurement of the level of the dome of liquid metal in the crucible.

EXEMPLE 2EXAMPLE 2

Pour traiter des déchets de zirconium, on a réalisé un creuset ayant sensiblement les mêmes dimensions que celui de l'exemple 1, avec seulement 2 différences : l'angle du cône était de 2,5° et la hauteur de la jupe conique inférieure non sectorisée était de 70 mm.To treat zirconium waste, a crucible was produced having substantially the same dimensions as that of Example 1, with only 2 differences: the angle of the cone was 2.5 ° and the height of the lower conical skirt not sectored was 70 mm.

La puissance de fonctionnement est de 35 kW aux bornes de l'inducteur, avec un courant de fréquence 9 kHz. On travaille sous argon à pression atmosphérique.The operating power is 35 kW at the terminals of the inductor, with a frequency current of 9 kHz. We work under argon at atmospheric pressure.

Le mode opératoire est le même que dans l'exemple 1. La hauteur de contact métal-paroi est comprise entre 2 et 8 mm pendant toute l'opération. En régime établi, l'alimentation en copeaux de zirconium est de 175 g/min, la vitesse de tirage de 1 cm/min. En 54 min, on obtient un lingot de 9,4 kg, ayant un bon état de surface et des teneurs en impuretés suivantes :

O₂
700 ppm
C
30 ppm
N₂
80 ppm
Cu
< 10 ppm
The procedure is the same as in Example 1. The height of metal-wall contact is between 2 and 8 mm during the whole operation. In steady state, the supply of zirconium chips is 175 g / min, the drawing speed of 1 cm / min. In 54 min, a 9.4 kg ingot is obtained, having a good surface condition and the following impurity contents:
Where
700 ppm
VS
30 ppm
No.
80 ppm
Cu
<10 ppm

EXEMPLE 3EXAMPLE 3

Pour purifier des copeaux d'alliage de titane TA6V, on a réalisé un creuset en cuivre à 16 secteurs, de diamètre intérieur 100 mm, de hauteur totale 280 mm.
Les secteurs s'étendent sur une hauteur de 230 mm à partir du haut.
La partie supérieure est cylindrique et a 130 mm de hauteur, la partie inférieure est tronconique avec un angle de 2° et avec une hauteur sectorisée de 100 mm.To purify TA6V titanium alloy chips, a copper crucible with 16 sectors was produced, with an internal diameter of 100 mm, with a total height of 280 mm.
The sectors extend over a height of 230 mm from the top.
The upper part is cylindrical and 130 mm high, the lower part is tapered with an angle of 2 ° and with a sectored height of 100 mm.

L'inducteur à 10 spires en tube de diamètre extérieur 8 mm, et d'épaisseur 1 mm, a une hauteur de 85 mm et un diamètre intérieur de 150 mm. On travaille sous argon à la pression atmosphérique, avec une puissance de 50 kW et une fréquence de 3 kHz, une alimentation de 466 g/min et une vitesse d'extraction de 1,3 cm/min. La hauteur de contact métal/paroi reste comprise entre 5 et 10 mm.
En 75 min, on obtient un lingot de 35 kg.The inductor with 10 turns in tube of outside diameter 8 mm, and thickness 1 mm, has a height of 85 mm and an inside diameter of 150 mm. We work under argon at atmospheric pressure, with a power of 50 kW and a frequency of 3 kHz, a supply of 466 g / min and an extraction speed of 1.3 cm / min. The metal / wall contact height remains between 5 and 10 mm.
In 75 min, a 35 kg ingot is obtained.

EXEMPLE 4 (fig. 3)EXAMPLE 4 (fig. 3)

Des barres de section rectangulaires 75 x 18 mm ont été obtenues à partir de copeaux d'alliage TA6V.
Le creuset 100 est rectangulaire, de côtés 75 et 1= 18 mm. La dimension transversale intérieure correspondante 1/2 est 9 mm. Sa hauteur totale est 110 mm. Il comprend, de haut en bas, une partie cylindrique sectorisée de 65 mm de hauteur, une partie conique sectorisée de 15 mm et une partie conique non sectorisée de 30 mm. L'angle du cône est 2°. Le nombre des secteurs est de 18. L'inducteur 106 à 6 spires a une hauteur de 50 mm. Il est constitué du même tube de cuivre que dans les exemples précédents. L'espace entre creuset et inducteur est de 10 mm, sauf au voisinage des angles où il est augmenté.
On travaille sous argon à la pression atmosphérique, avec une puissance de 35 kW aux bornes de l'inducteur, une fréquence de 100 kHz, un débit d'alimentation de 175 g/min et une vitesse de tirage de 2,9 cm/min. La hauteur de contact métal-paroi est entre 5 et 10 mm. En 11 min, on obtient un lingot de 1,8 kg.Bars of rectangular section 75 x 18 mm were obtained from TA6V alloy chips.
The crucible 100 is rectangular, with sides 75 and 1 = 18 mm. The corresponding internal transverse dimension 1/2 is 9 mm. Its total height is 110 mm. It comprises, from top to bottom, a sectorized cylindrical part of 65 mm in height, a sectorized conical part of 15 mm and a non-sectorized conical part of 30 mm. The angle of the cone is 2 °. The number of sectors is 18. The inductor 106 with 6 turns has a height of 50 mm. It is made of the same copper tube as in the previous examples. The space between crucible and inductor is 10 mm, except in the vicinity of the angles where it is increased.
We work under argon at atmospheric pressure, with a power of 35 kW at the terminals of the inductor, a frequency of 100 kHz, a feed rate of 175 g / min and a drawing speed of 2.9 cm / min . The metal-wall contact height is between 5 and 10 mm. In 11 min, a 1.8 kg ingot is obtained.

EXEMPLE 5 (Figure 4)EXAMPLE 5 (Figure 4)

Cette figure représente une variante de l'Exemple 4, où l'inducteur 206 d'espacement sensiblement constant avec les secteurs du creuset 200, est entouré de tôles magnétiques 2060 sur ses parties rectilignes, de façon à augmenter le champ dans les zones correspondantes.This figure represents a variant of Example 4, where the inductor 206 of substantially constant spacing with the sectors of the crucible 200, is surrounded by magnetic sheets 2060 on its rectilinear parts, so as to increase the field in the corresponding zones.

Claims (10)

  1. A method of melting and casting metals, wherein a crucible (1) with a wall comprising longitudinal sectors (2) electrically insulated from one another is continuously fed with solid metal in divided form; wherein the metal is melted by induction, using an inductor (6) with helical windings surrounding the crucible (1); wherein the metal thus melted is confined electromagnetically and cooled by circulating a cooling fluid within the crucible wall; and wherein the metal is extracted in the solidified state by drawing it down at a speed corresponding to the feed, characterised in that the wall of the crucible (1) is divided into an upper sectorised zone (4) with vertical generatrices and a sectorised zone (5) with downwardly diverging generatrices , located in the lower position and connected to the upper zone (4); the inductor (6) is positioned so that its lowest winding (60) is at the level of the join (45) between the upper and lower zones (4,5); and the molten metal is confined electromagnetically, so that the metal is in contact with the wall of the crucible, in the absence of slag, only over a limited height not exceeding 1 cm above the join (45), facilitating extraction of the solidified metal and improving its surface state.
  2. The method of claim 1, wherein the molten metal is confined so that it is in contact with the wall over a height of 2 to 5
  3. The method of claim 1 or 2, wherein the feed and extraction are kept constant, so that the top (9) of the dome of liquid metal (10) is substantially at the level of the highest winding (11) of the inductor (6).
  4. A melting and continuous casting apparatus for use in carrying out the method of any of claims 1 to 3, comprising a cold conductive crucible (1;100) with a vertical axis, the wall of which is formed, over at least part of its height, by longitudinal sectors (2) which are electrically insulated from one another and have a cooling fluid flowing through them; an inductor (6) with helical windings surrounding the crucible (1;100) over part of its height, and supplied with medium or high frequency alternating current which serves both to heat and confine the metal, and a system (7 and 26 and 27) for drawing down the ingot; the crucible (1;100) having a lower sectorised zone (5) with downwardly diverging generatrices, characterised in that, the apparatus being designed for melting and continuous casting of metals, the crucible (1;100) comprises an upper sectorised zone (4) with vertical generatrices, that the upper zone (4) is connected to the lower sectorised zone (5), and that the lowest winding (60) of the inductor (6) is at the level of the join (45) between the zones, the apparatus thus enabling metal to be melted and cast without slag and preventing metal from being pulled off the crucible wall.
  5. The apparatus of claim 4, wherein the lower sectorised zone (5) with downwardly diverging generatrices is extended downwardly by a sectorised zone with vertical generatrices, the height of the first zone being at least equal to 1/4 of the internal transverse dimension of the crucible.
  6. The apparatus of claim 4, wherein the lower sectorised zone (5) of the crucible is extended downwardly by a cooled, nonsectorised zone (3).
  7. The apparatus of any of claims 4 to 6, wherein the angle of inclination of the generatrices of the lower sectorised zone (5) of the crucible (1) is from 1° to 5°.
  8. The apparatus of any of claims 4 to 7, wherein the inner wall of the upper zone (4) of the crucible (1) is of circular cylindrical shape, and wherein the inner wall of the lower sectorised zone (5) is of frustoconical shape.
  9. The apparatus of any of claims 4 to 7, wherein the inner wall of the upper zone (4) of the crucible (100) is of polygonal cylindrical shape.
  10. Use of the apparatus of any of claims 4 to 9 for melting and continuously casting one of the metals or alloys of the group formed by: refractory metals of Groups IV, V and VI and their alloys, rare earths, aluminium, copper, silicon, nickel-based alloys and cobalt-based alloys.
EP88420010A 1987-01-15 1988-01-13 Process and device for melting and continuously casting metals Expired - Lifetime EP0275228B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT88420010T ATE83597T1 (en) 1987-01-15 1988-01-13 PROCESS AND PLANT FOR MELTING AND CONTINUOUS CASTING OF METALS.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8700814 1987-01-15
FR8700814A FR2609655B1 (en) 1987-01-15 1987-01-15 CONTINUOUS MELTING AND CASTING DEVICE, METHOD FOR IMPLEMENTING SAME AND USE THEREOF

Publications (2)

Publication Number Publication Date
EP0275228A1 EP0275228A1 (en) 1988-07-20
EP0275228B1 true EP0275228B1 (en) 1992-12-16

Family

ID=9347226

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88420010A Expired - Lifetime EP0275228B1 (en) 1987-01-15 1988-01-13 Process and device for melting and continuously casting metals

Country Status (10)

Country Link
US (1) US4838933A (en)
EP (1) EP0275228B1 (en)
JP (1) JPS63192543A (en)
KR (1) KR910007297B1 (en)
AT (1) ATE83597T1 (en)
CA (1) CA1326752C (en)
DE (1) DE3876638T2 (en)
ES (1) ES2036275T3 (en)
FR (1) FR2609655B1 (en)
NO (1) NO169877C (en)

Families Citing this family (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5033948A (en) * 1989-04-17 1991-07-23 Sandvik Limited Induction melting of metals without a crucible
FR2648065A1 (en) * 1989-06-12 1990-12-14 Solvay DEVICE FOR RECOVERING BY MELTING THE METAL CONSTITUTING A FUSE CORE
FR2648829B1 (en) * 1989-06-22 1993-12-31 Jeumont Schneider METHOD AND DEVICE FOR SEPARATING THE CONSTITUENTS OF AN ALLOY
DE3923550C2 (en) * 1989-07-15 1997-10-23 Ald Vacuum Techn Gmbh Process and permanent mold for molding electrically conductive materials
US5193607A (en) * 1990-05-15 1993-03-16 Daido Tokushuko K.K. Method for precision casting of titanium or titanium alloy
JP3287031B2 (en) * 1991-10-16 2002-05-27 神鋼電機株式会社 Cold wall induction melting crucible furnace
US5528620A (en) * 1993-10-06 1996-06-18 Fuji Electric Co., Ltd. Levitating and melting apparatus and method of operating the same
US5460642A (en) * 1994-03-21 1995-10-24 Teledyne Industries, Inc. Aerosol reduction process for metal halides
US6158498A (en) * 1997-10-21 2000-12-12 Wagstaff, Inc. Casting of molten metal in an open ended mold cavity
SE512774C2 (en) * 1998-03-06 2000-05-08 Abb Ab Device for casting metal
US6289033B1 (en) 1998-12-08 2001-09-11 Concurrent Technologies Corporation Environmentally controlled induction heating system for heat treating metal billets
FR2808809B1 (en) * 2000-05-11 2003-06-27 Emix CONTINUOUS MANUFACTURING INSTALLATION OF MULTICRYSTALLINE SILICON BAR
JP4496623B2 (en) * 2000-08-18 2010-07-07 シンフォニアテクノロジー株式会社 Induction heating melting furnace
TWI265198B (en) * 2002-12-02 2006-11-01 Univ Nat Taiwan The method and equipments for controlling the solidification of alloys in induction melting using cold crucible
JP4664967B2 (en) * 2005-02-17 2011-04-06 Ｓｕｍｃｏソーラー株式会社 Silicon casting apparatus and silicon substrate manufacturing method
JP5048222B2 (en) * 2005-04-01 2012-10-17 株式会社神戸製鋼所 Method for producing long ingots of active refractory metal alloys
JP2007051026A (en) 2005-08-18 2007-03-01 Sumco Solar Corp Method for casting silicon polycrystal
JP5141020B2 (en) 2007-01-16 2013-02-13 株式会社Ｓｕｍｃｏ Casting method of polycrystalline silicon
JP2008194700A (en) * 2007-02-08 2008-08-28 Shinko Electric Co Ltd Continuous casting device, extraction control device and extraction control method in the same
KR101238144B1 (en) * 2009-02-09 2013-02-28 도호 티타늄 가부시키가이샤 Titanium slab for hot-rolling, and smelting method and rolling method therefor
US9039835B2 (en) * 2009-07-20 2015-05-26 Solin Development B.V. Apparatus for producing multicrystalline silicon ingots by induction method
CN103442825B (en) * 2011-03-14 2017-01-18 康萨克公司 Open bottom electric induction cold crucible for use in electromagnetic casting of ingots
US20170072461A1 (en) * 2015-09-15 2017-03-16 Retech Systems Llc Laser sensor for melt control of hearth furnaces and the like
CN115261663B (en) * 2022-08-01 2023-05-02 江西蓝微电子科技有限公司 Gold alloy bonding wire and preparation method thereof

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3775091A (en) * 1969-02-27 1973-11-27 Interior Induction melting of metals in cold, self-lined crucibles
GB1221909A (en) * 1969-10-01 1971-02-10 Standard Telephones Cables Ltd Improvements in or relating to apparatus for the heat treatment of electrically conductive materials
FR2303774A1 (en) * 1975-03-10 1976-10-08 Fizichesky Inst Im P N Crystalline refractory oxide mfr. by continuous induction melting - suitable for mfg. lanthanum chromite and similar materials
FR2497050A1 (en) * 1980-12-23 1982-06-25 Saphymo Stel COLD CAGE DIRECT INDUCTION FUSION DEVICE WITH ELECTROMAGNETIC CONTAINMENT OF MOLTEN LOAD

Also Published As

Publication number Publication date
EP0275228A1 (en) 1988-07-20
NO880149D0 (en) 1988-01-14
KR880008848A (en) 1988-09-13
DE3876638T2 (en) 1993-06-24
DE3876638D1 (en) 1993-01-28
KR910007297B1 (en) 1991-09-24
US4838933A (en) 1989-06-13
JPS63192543A (en) 1988-08-09
ES2036275T3 (en) 1993-05-16
ATE83597T1 (en) 1993-01-15
FR2609655A1 (en) 1988-07-22
NO169877B (en) 1992-05-11
JPH0258022B2 (en) 1990-12-06
FR2609655B1 (en) 1989-03-24
NO169877C (en) 1992-08-19
NO880149L (en) 1988-07-18
CA1326752C (en) 1994-02-08

Similar Documents

Publication Publication Date Title
EP0275228B1 (en) Process and device for melting and continuously casting metals
US4915723A (en) Apparatus for casting silicon with gradual cooling
JPH09278590A (en) Forming ingot by unidirectionally coagulating molten liquid consisting of silicon in bottomless type crystallization room and device therefor
FR2656552A1 (en) PROCESS FOR THE PRODUCTION OF THIXOTROPIC METALLIC PRODUCTS BY CONTINUOUS CASTING WITH ELECTROMAGNETIC CURRENT POLYPHASE CURING.
FR2688516A1 (en) Device for the manufacture of metals and metal alloys of high purity
EP0351327A1 (en) Method for fabrication of thixotrope metallic products by continuous casting
EP0636848A1 (en) Smelting process of electrically-conductive materials in an induction smelting furnace with a cold crucible and furnace therefor
FR2480154A1 (en) METHOD AND APPARATUS FOR ELECTROMAGNETIC CASTING THIN BANDS
EP0141999B1 (en) Process for making a polycrystalline semiconductor material ingot
EP0092477B1 (en) Process and apparatus for casting hollow steel ingots
EP0907756A1 (en) Processing of electroslag refined metal
EP1753695A2 (en) Silicon refining installation
JPH0230698A (en) Casting device of silicon
JPH01264920A (en) Silicon casting device
CH628544A5 (en) PROCESS AND INSTALLATION FOR THE CONTINUOUS CASTING OF TUBULAR PRODUCTS.
EP0050581A1 (en) Process and apparatus for continuously casting hollow metal ingots
EP0241387B1 (en) Casting mould for the regulation of the free surface level of the molten metal contacting the mould during vertical casting
WO1986001756A1 (en) Method for regulating the level of the contact line of the free metal surface with the ingot mould in a continuous vertical casting
EP0249565B1 (en) Device for regulating the level of the contact line of the free metal surface with the continuous casting mould in a vertical casting
FR3090430A1 (en) Installation and process for obtaining a titanium alloy or titanium intermetallic product
BE894795A (en) Electric melting and refining furnace for glass - where batch flows vertically downwards through melting, refining and conditioning zones
BE1011970A3 (en) Process development of a metal jacket on a tree.
BE1008485A3 (en) Method and four for the manufacture of a product fade.
JP4672203B2 (en) Method for producing ingot for gold bonding wire
EP0452294B1 (en) Method and device for the continuous casting of a metal

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH DE ES GB IT LI NL SE

17P Request for examination filed

Effective date: 19880801

17Q First examination report despatched

Effective date: 19910402

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT BE CH DE ES GB IT LI NL SE

REF Corresponds to:

Ref document number: 83597

Country of ref document: AT

Date of ref document: 19930115

Kind code of ref document: T

ITF It: translation for a ep patent filed
GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)

Effective date: 19921215

REF Corresponds to:

Ref document number: 3876638

Country of ref document: DE

Date of ref document: 19930128

REG Reference to a national code

Ref country code: ES

Ref legal event code: FG2A

Ref document number: 2036275

Country of ref document: ES

Kind code of ref document: T3

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
EAL Se: european patent in force in sweden

Ref document number: 88420010.6

REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CH

Payment date: 20061215

Year of fee payment: 20

Ref country code: AT

Payment date: 20061215

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 20061218

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: SE

Payment date: 20061220

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20070110

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20070112

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: ES

Payment date: 20070123

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: BE

Payment date: 20070201

Year of fee payment: 20

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: IT

Payment date: 20070607

Year of fee payment: 20

BE20 Be: patent expired

Owner name: CIE EUROPEENNE DU ZIRCONIUM *CEZUS

Effective date: 20080113

REG Reference to a national code

Ref country code: GB

Ref legal event code: PE20

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

NLV7 Nl: ceased due to reaching the maximum lifetime of a patent

Effective date: 20080113

EUG Se: european patent has lapsed
REG Reference to a national code

Ref country code: ES

Ref legal event code: FD2A

Effective date: 20080114

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION

Effective date: 20080113

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION

Effective date: 20080112

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: ES

Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION

Effective date: 20080114