EP1633512A2 - Continouos casting installation for the electromagnetic rotation of molten metal moving inside the nozzle - Google Patents

Continouos casting installation for the electromagnetic rotation of molten metal moving inside the nozzle

Info

Publication number
EP1633512A2
EP1633512A2 EP04767284A EP04767284A EP1633512A2 EP 1633512 A2 EP1633512 A2 EP 1633512A2 EP 04767284 A EP04767284 A EP 04767284A EP 04767284 A EP04767284 A EP 04767284A EP 1633512 A2 EP1633512 A2 EP 1633512A2
Authority
EP
European Patent Office
Prior art keywords
nozzle
inductor
continuous casting
molten 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
Application number
EP04767284A
Other languages
German (de)
French (fr)
Other versions
EP1633512B1 (en
Inventor
Jean-Marie Galpin
Gérard PERRIN
Marc Anderhuber
Robert Bolcato
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.)
ArcelorMittal France SA
Original Assignee
USINOR 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 USINOR SA filed Critical USINOR SA
Priority to PL04767284T priority Critical patent/PL1633512T3/en
Priority to SI200430240T priority patent/SI1633512T1/en
Publication of EP1633512A2 publication Critical patent/EP1633512A2/en
Application granted granted Critical
Publication of EP1633512B1 publication Critical patent/EP1633512B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

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
    • B22D41/50—Pouring-nozzles
    • B22D41/62—Pouring-nozzles with stirring or vibrating means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/10—Supplying or treating molten metal
    • B22D11/11—Treating the molten metal
    • B22D11/114—Treating the molten metal by using agitating or vibrating means
    • B22D11/115—Treating the molten metal by using agitating or vibrating means by using magnetic fields
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/16—Controlling or regulating processes or operations
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D27/00—Treating the metal in the mould while it is molten or ductile ; Pressure or vacuum casting
    • B22D27/02—Use of electric or magnetic effects
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H2250/00—Electrical heat generating means
    • F24H2250/08—Induction

Definitions

  • Continuous casting apparatus for electromagnetic rotation of the liquid metal in transit through the casting nozzle.
  • the present invention relates to the continuous casting of metals, steel in particular, implementing a submerged casting nozzle which is immersed in a mold placed underneath. More specifically, the invention relates to the axial rotation of the liquid metal in transit in such a nozzle between the tundish and the mold. It is known that the axial rotation of the metal already within the casting nozzle is a recognized means for controlling the flows in the mold by modifying the distribution of the gas bubbles and inclusions present in the liquid metal before it arrives in the mold.
  • the rotation of the flows in the pouring nozzle thus appears as an effective means for combating the appearance of surface appearance defects, such as blistering and exfoliations, on cold-lined sheets of steel grades for application. automotive and packaging steels.
  • This technique therefore enables the reduction of the writing operations on continuously cast slabs (reduction or even elimination of surface defects on exfoliation-type sheets), the elimination of downgrades and disputes for blistered defects, as well as the increase in productivity. machines by lengthening sequences and increasing casting speeds.
  • the rotating of the liquid metal in the pouring nozzle has already been proposed using different types of actuators. Two types of actuators can be schematically distinguished: "passive" actuators and "active" ones.
  • the "passive" actuators are, among other things, the design modifications of the inner wall of the nozzle (for example: spirals), the members such as the helix, the internal helical nozzle, etc. which are implanted in the body of the nozzle itself. , or the modifications of the upper portion of the nozzle at the junction with the distributor (for example: acceleration cone) or the modifications of the actual body for regulating the metal flow in the nozzle.
  • the major disadvantages of this type actuators are to generate a rotation speed directly dependent on the metal flow passing through the nozzle and to constitute preferred sites of deposits of inclusions in the nozzle, resulting in a potential increase in the risk of clogging.
  • the "active" actuators are essentially of electromagnetic nature: a polyphase type static annular electromagnetic inductor surrounds the nozzle at a small distance over part of its length and generates a magnetic field rotating around the casting axis intended to drive in axial rotation with him the liquid metal present in the nozzle. Examples are described in JP 06 023498 or JP 07 108355 or JP 07 148561. However, the electromagnetic devices heretofore proposed are, for the most part, based on the tangential rotating field linear stators technology operating at low or very low frequency ( ⁇ 10 Hz).
  • the others are magnetic field through, so salient poles wound to a pair of poles by phases facing one another on either side of the axis of the nozzle.
  • the invention falls within this category. They make it possible to overcome some of the disadvantages mentioned above, in particular the phenomenon of central depression. However, the smallness of the location combined with a necessarily high electrical power installed, as well as the desired reduction of the air gap by bringing the protruding inward polar tooth protruding beyond the winding and the nozzle to maximize the electromagnetic coupling.
  • the object of the present invention is to propose a solution for an electromagnetic rotation of the liquid metal within a casting nozzle which does not have the drawbacks of known solutions.
  • the subject of the invention is a continuous casting plant for metals, in particular steel, in which the submerged nozzle through which the molten metal to be poured arrives in the mold from a pouring distributor located above is surrounded by an electromagnetic annular magnetic field inductor rotating around the casting axis for driving in axial rotation with it the molten metal, said inductor being of polyphase type with a magnetic field having a pair of poles per phase and each pole of which is formed by an electric winding wound around an inwardly projecting pole tooth terminating in a polar face disposed opposite and in proximity to the nozzle, the pole teeth being interconnected by a bolt external magnetic magnetic flux closing device, characterized in that each polar tooth has a lateral narrowing (a bevel for example) at the end of its projecting portion, which increases the distance separating the polar faces between them.
  • a lateral narrowing a bevel for example
  • the annular inductor is formed in two pivotally articulated half-shells that can close around the nozzle.
  • the invention implements a so-called "through” magnetic field, that is to say passing through the axis of the nozzle without noticeable weakening of its intensity between the edge and the center of that -this. Due to the technological base chosen, namely that with a pair of poles per phase of the power supply supplying a polyphase annular inductor with wound salient poles distributed around the nozzle, the rotating magnetic field produced is of the desired "through” type .
  • the casting axis is at the center of the air gap of the inductor and the produced field prospers in this gap through the casting axis for, from a given magnetic pole, join the magnetic pole paired opposite sign located opposite and not next to it as it would be the case with an inductor with distributed poles or several pairs of poles per phase.
  • this type of technology is not new in itself. It is even quite widely used for the rotation of the liquid metal cast, not in a nozzle, but in the mold itself, so in the case of inductors to rotate (the liquid metal column) much larger apparent diameter than that of the metal jet in the nozzle and with a correspondingly much lower rotational angular velocity requirement (see for example USP 4,462,458).
  • FIG. 1 is a diagram representative, seen in cross section, the inductor in two butted half-shells provided with its internal heat shield bordering the gap
  • - Figure 2 is a diagram similar to the previous one but intended to show the propagation of the lines of force of the magnetic field through the gap as frozen at any given time of the operation of the inductor
  • FIG. 3 is a block diagram showing the articulation of the two half-shells constituting the inductor
  • FIG. 4 shows the map of the velocities of the liquid metal rotating within the casting nozzle under the effect of the magnetic field in a plane of cross section of the nozzle;
  • FIG. 5 shows the evolution of the intensity B of the magnetic field in the air gap along a diameter D of the nozzle taken in a plane situated at half height of the inductor;
  • FIG. 6 shows, in correspondence with the representation of FIG. 5, the correlative evolution of the magnetic force field F B along a diameter D of the nozzle according to a radial profile R and according to a orthoradial profile OR.
  • the same elements are designated by identical references. As can be seen with reference to FIGS.
  • the inductor 1 is a linear motor stator closed on itself, constituted for this purpose by two independent, equal semicubular portions 2a and 2b, shells).
  • Each half-shell comprises three coiled protruding poles 3, the polar face 4 of which faces inwards, these magnetic poles, made of assembled stacked soft iron sheets, being conventionally connected to each other by an outer peripheral hemi-tubular yoke 5, 5b.
  • the set is sized so that the two paired heads come together in the junction plane J when the inductor is in the closed working position shown in Figures 1 and 2.
  • a cap 7a, 7b, also of corresponding hemi-tubular form internally cape the polar faces of each half-shell and form, once the inductor in the closed position, a thermal protection screen 7 which surrounds at a short distance the casting nozzle.
  • This thermal protection is desirable for the electric windings 3 of the inductor with respect to the radiation emitted by the pouring nozzle 8 shown in FIG. 3 and channeling the flow of molten metal towards the mold. Details on the possible constitution of this screen will be given later.
  • the electrical winding 6 of each coiled pole 3 is connected to a phase of a three-phase power supply (not shown) intended to supply the primary current of the inductor.
  • any protruding pole of one of the half-shells 2a is diametrically opposite a projecting pole of the other half-shell 2b.
  • These two poles form a "pair of poles" in the sense that they are both connected to the same phase of the power supply, but in opposition (for example via a different winding direction) so that, at every moment, their active faces are of opposite signs. This condition is necessary for the magnetic field produced to be of the through type.
  • the magnetic flux return poles 3 and 5a, 5b are laminated into grain-oriented Fe-Si plates having an initial thickness of 0.3 mm in order to minimize the hysteresis losses.
  • Their operating height is between 50 (minimum value) and 500 mm, depending on the space available between the distributor and the top of the mold between which the inductor will take place.
  • Their internal diameter is of the order of the outer diameter of the casting nozzle increased by a few tens of mm to preserve a separation but in order to ensure the best possible inductive coupling.
  • the primary windings 6 consist of a large number (several hundred) of very small copper wire turns supporting high current densities (> 10 A / mm). They are provided within them water-cooled copper heat extractors (not shown). These coils are supplied with three-phase currents at medium frequency ranging from 50 Hz to 600 Hz.
  • this static motor constituting the inductor 1 can generate in its gap occupied by the nozzle a transverse electromagnetic field (said through) of high intensity (between 1000 and 1500 gauss) for low values. inductive currents (a few tens of amperes). This field, as seen in the diagram, is almost uniform in the central part of the gap.
  • This essential characteristic of the invention makes it possible to generate in the liquid metal a field of forces uniformly decreasing from the wall to the center, as shown in the diagram of FIG. 6. This allows, as the speed chart also clearly shows. of Figure 4, to rotate the liquid metal with a speed that remains high even in the axial portion of the nozzle. This specificity is necessary to avoid a too strong depression in the central part of the nozzle where the metal would then tend to "leak" and undergo a strong downward vertical acceleration, thus canceling part of the beneficial effect of rotating . As clearly shown in FIG.
  • the intensity of the primary currents can be greatly increased.
  • the proposed technique makes it possible, in a wide range of intensity of the primary currents, to increase very strongly the intensity of the electromagnetic field in the gap, by increasing the intensity of these currents to values well beyond the threshold intensity corresponding to the magnetic saturation of the cylinder head 5. This allows to channel the magnetic field lines and increase, in the air gap of the motor, the intensity of this magnetic field until the latter reaches its saturation value in the cylinder head.
  • the inductor is very close (at about 5 mm distance) from the casting nozzle 8 whose outside temperature is of the order of 1100 to 1200 ° C. Its thermal protection, vis-à-vis the radiation emitted by the nozzle, is then provided by the segmented copper screen 7, of thin thickness, cooled by water circulation and transparent to the electromagnetic field through this segmentation.
  • the inductor is advantageously held by a support consisting of two arms 9 articulated about a pivoting axis 10.
  • the arms are driven by jacks 11 which ensure their closing-opening and allow to exert a sufficient contact force (greater than 200 kgf) between the yokes 5a and 5b of the two hemi-tubular parts 2a and

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)
  • Casting Support Devices, Ladles, And Melt Control Thereby (AREA)

Abstract

The invention relates to a continuous casting installation for metals, particularly steel, in which the submerged nozzle (8) is surrounded by an annular electromagnetic inductor (1) with a magnetic field that rotates around the casting axis, which is intended to drive the molten metal in axial rotation therewith. The invention is characterised in that the aforementioned inductor is of the polyphase type with a magnetic field passing therethrough and is equipped with a pair of projecting poles (3) per phase. Moreover, the end of each projecting pole opposite the nozzle is provided with a lateral narrowing (12) which increases the distance separating the polar ends (4). In this way, the inductor is extremely compact and very powerful and can deliver an intense traversing field into the central part of the nozzle, using a high-frequency primary current, such as to produce the effective rotation of the molten metal moving therein. The invention is particularly suitable for the continuous casting of slabs, using a submerged nozzle with lateral outlets.

Description

Installation de coulée continue pour une mise en rotation électromagnétique du métal liquide en transit dans la busette de coulée. Continuous casting apparatus for electromagnetic rotation of the liquid metal in transit through the casting nozzle.
La présente invention a trait à la coulée continue des métaux, de l'acier en particulier, mettant en œuvre une busette de coulée immergée qui plonge dans une lingotière placée en dessous. Plus précisément, l'invention concerne la mise en rotation axiale du métal liquide en transit au sein d'une telle busette entre le répartiteur de coulée et la lingotière. On sait que la mise en rotation axiale du métal déjà au sein de la busette de coulée est un moyen reconnu de contrôle des écoulements dans la lingotière en modifiant la répartition des bulles de gaz et inclusions présentes dans le métal liquide avant son arrivée en lingotière. On parvient ainsi à: - réduire, voire éliminer, les dépôts d'inclusions le long de la paroi intérieure de la busette ainsi que, en cas de busette à ouies de sortie latérales pour la coulée de brames, au niveau de ses ouïes et de sa cuvette de fond; - réduire fortement la profondeur de pénétration des bulles de gaz et inclusions dans le puits liquide du produit en cours de coulée, donc également le risque de leur piégeage sur la face intrados des produits coulés sur machine courbe - réduire la vitesse de circulation du métal liquide sous le ménisque ainsi que les fluctuations de niveau de celui-ci; - limiter les instabilités d'écoulement, de type balancements de jets, dans la lingotière en générant un effet "gyroscopique" sur les écoulements dans la busette. La mise en rotation des écoulements dans la busette de coulée apparaît ainsi comme un moyen efficace pour lutter contre l'apparition des défauts d'aspect de surface, de type boursouflures et exfoliations, sur les tôles lammées à froid des nuances d'acier pour application automobile et des aciers pour emballage. Cette technique permet donc la réduction des opérations d'écriquage sur les brames coulées en continu (réduction voire suppression des défauts de surface sur tôles de type exfoliation), la suppression des déclassements et des litiges pour défauts boursouflés, ainsi que l'augmentation de productivité des machines par l'allongement des séquences et l'augmentation des vitesses de coulée. La mise en rotation du métal liquide dans la busette de coulée a déjà été proposée en utilisant différents types d'actionneurs. On peut schématiquement distinguer deux types d'actionneurs: les actionneurs "passifs" et les" actifs". Les actionneurs "passifs" sont entre autres les modifications de design de la paroi interne de la busette (par exemple: spirales), les organes tels que hélice, busette interne hélicoïdale, etc... qui sont implantés dans le corps même de la busette, ou les modifications de la partie supérieure de la busette à la jonction avec le répartiteur (par exemple: cône d'accélération) ou encore les modifications de l'organe même de régulation du débit métal dans la busette. Les inconvénients majeurs de ce type d'actionneurs sont de générer une vitesse de rotation directement dépendante du débit métal transitant dans la busette et de constituer des sites privilégiés de dépôts d'inclusions dans la busette, d'où une augmentation potentielle des risques de bouchage. Les actionneurs "actifs" sont essentiellement de nature électromagnétique: un inducteur électromagnétique annulaire statique de type polyphasé entoure la busette à faible distance sur une partie de sa longueur et génère un champ magnétique tournant autour de l'axe de coulée destiné à entraîner en rotation axiale avec lui le métal liquide présent dans la busette. On trouvera au besoin des exemples décrits dans les documents JP 06 023498 ou JP 07 108355 ou encore JP 07 148561. Cependant, les dispositifs électromagnétiques jusqu'ici proposés sont, pour la plupart, basés sur la technologie des stators linéaires à champ tournant tangentiel fonctionnant à basse, voire à très basse fréquence (<10 Hz). Ces dispositifs présentent notamment les inconvénients de: - générer des vitesses de rotation souvent trop faibles, compte tenu des fréquences de courant utilisées, pour obtenir les effets souhaités (par exemple, à 4 Hz triphasé utilisable pour un diamètre interne de busette de 80 mm, la vitesse de rotation théorique maximale est de 80 t/min), - générer dans le métal liquide un champ de force fortement concentré près, de la paroi intérieure de la busette, ce qui a pour conséquence de créer une zone de forte dépression dans la partie centrale de la busette où le métal est alors accéléré dans la direction verticale descendante; - devoir fonctionner avec des courants électriques de forte intensité (>300-500 A), ce qui conduit à des dispositifs de taille importante afin de pouvoir assurer leur refroidissement, donc peu aisés à mettre en œuvre sur une machine de coulée continue et de plus nécessiter l'utilisation de générateur électrique très onéreux. Les autres sont à champ magnétique traversant, donc à pôles saillants bobinés à une paire de pôles par phases en regard l'un de l'autre de part et d'autre de l'axe de la busette. L'invention s'inscrit dans cette catégorie. Ils permettent de s'affranchir de certains des inconvénients prémentionnés, en particulier du phénomène de dépression centrale. Toutefois, l'exiguïté de l'endroit alliée à une puissance électrique installée nécessairement élevée, ainsi que la diminution recherchée de l'entrefer par rapprochement entre la dent polaire saillante vers l'intérieur dépassant l'enroulement et la busette pour maximiser le couplage électromagnétique, conduisent inévitablement en fait à une détérioration du rendement énergétique en même temps qu'à un certain degré de désorganisation possible des mouvements de rotation du métal suite, notamment, à des risques de pontages parasites du flux magnétique entre pôles trop voisins appartenant à des phases différentes de l'alimentation électrique. Le but de la présente invention est de proposer une solution à une mise en rotation électromagnétique du métal liquide au sein d'une busette de coulée qui ne présente pas les inconvénients des solutions connues. A cet effet, l'invention a pour objet une installation de coulée continue des métaux, de l'acier en particulier, dans laquelle la busette immergée par laquelle le métal en fusion à couler arrive en lingotière depuis un répartiteur de coulée situé au-dessus est entourée par un inducteur électromagnétique annulaire statique à champ magnétique mobile tournant autour de l'axe de coulée destiné à entraîner en rotation axiale avec lui le métal en fusion, ledit inducteur étant de type polyphasé à champ magnétique traversant pourvu d'une paire de pôles par phase et dont chaque pôle est formé par un enroulement électrique bobiné autour d'une dent polaire saillante vers l'intérieur se terminant par une face polaire disposée en regard et à proximité de la busette, les dents polaires étant reliées entre elles par une culasse magnétique périphérique extérieure de fermeture du flux magnétique, installation caractérisée en ce que chaque dent polaire présente un rétrécissement latéral (un biseau par exemple) à l'extrémité de sa partie saillante, qui augmente la distance séparant les faces polaires entre elles. Selon une variante avantageuse, l'inducteur annulaire est formé en deux demi- coquilles articulées pivotantes pouvant se refermer autour de la busette. Comme on l'aura sans doute compris, l'invention met en œuvre un champ magnétique dit "traversant", c'est à dire passant par l'axe de la busette sans affaiblissement notoire de son intensité entre le bord et le centre de celle-ci. , Grâce à la base technologique retenue, à savoir celle à une paire de pôles par phase de l'alimentation électrique alimentant un inducteur annulaire polyphasé à pôles saillants bobinés répartis autour de la busette, le champ magnétique tournant produit est du type "traversant" recherché. Autrement-dit, à chaque instant, l'axe de coulée est au centre de l'entrefer de l'inducteur et le champ produit prospère dans cet entrefer en passant par l'axe de coulée pour, depuis un pôle magnétique donné, rejoindre le pôle magnétique apparié de signe contraire situé en face et non à côté de lui comme ce serait le cas avec un inducteur à pôles répartis ou à plusieurs paires de pôles par phase. On rappelle que ce type de technologie n'est pas nouveau en soi. Il est même assez largement utilisé pour la mise en rotation du métal liquide coulé, non pas au sein d'une busette, mais dans la lingotière elle-même, donc dans le cas d'induits à faire tourner (la colonne de métal liquide) de bien plus grand diamètre apparent que celui du jet de métal dans la busette et avec une exigence de vitesse angulaire de rotation corrélativement bien moindre (voir par exemple USP 4 462 458). Or, contrairement aux idées reçues, il s'avère que le transfert de cette technologie depuis la lingotière à la busette de coulée peut, sans nécessairement consentir à une baisse de puissance installée marquée, s'accompagner d'une réduction de taille de l'inducteur compatible avec le montage de dernier autour et au plus près d'une busette de coulée pourvu que l'on conserve le caractère "traversant", en tous cas essentiellement "traversant", du champ magnétique produit, et ce sans nuire alors à son nécessaire refroidissement. Or, c'est précisément là que se trouve l'idée à la base de l'invention: parvenir, sans pénaliser les performances de l'inducteur, préserver ce caractère "traversant" du champ malgré la compacité de l'inducteur et la minimisation de l'entrefer en consentant à une légère perte de masse magnétique localisée à des endroits choisis des pôles saillants, à savoir les bords des faces actives, pour contre-carrer la tendance naturelle du champ magnétique de se propager dans l'entrefer selon les chemins les moins reluctants en bouclant entre des pôles voisins proches les uns des autres. Des tests réalisés sur acier ont confirmé la capacité d'un tel inducteur à mettre en rotation le métal s 'écoulant dans une busette immergée dans des conditions de coulée bien plus sévères que celles qui seront rencontrées dans les machines industrielles de blooms ou de brames. Ces tests ont été effectués en effet avec une busette de type droite (ouïe axiale unique s'ouvrant dans le fond) dans laquelle le métal s'écoulait à une vitesse moyenne de l'ordre de 3.5 à 4.2 m/s, sachant que dans une busette de coulée de brames, les vitesses moyennes débitant sont plutôt comprises entre 1,5 et 2,0 m/s. L'invention sera de toute façon bien comprise et d'autres aspects et avantages apparaîtront au vu de la description qui suit donnée à titre d'exemple de réalisation et en référence aux planches de dessins annexées sur lesquelles: - la figure 1 est un schéma représentant, vu en section droite, l'inducteur en deux demi-coquilles aboutées pourvu de son écran thermique interne bordant l'entrefer; - la figure 2 est un schéma analogue au précédent mais destiné à bien montrer la propagation des lignes de force du champ magnétique traversant dans l'entrefer telles que figées à un instant donné quelconque du fonctionnement de l'inducteur; - la figure 3 est un schéma fonctionnel de principe montrant l'articulation des deux demi-coquilles constitutives de l'inducteur; - la figure 4 montre la carte des vitesses du métal liquide tournant au sein de la busette de coulée sous l'effet du champ magnétique dans un plan de section droite de la busette; - la figure 5 montre l'évolution de l'intensité B du champ magnétique dans l'entrefer le long un diamètre D de la busette pris dans un plan situé à mi hauteur de l'inducteur; - la figure 6 montre, en correspondance avec la représentation de la figure 5, l'évolution corrélative du champ de forces magnétiques FB le long d'un diamètre D de la busette selon un profil radial R et selon un profil orthoradial OR. Sur les figures, les mêmes éléments sont désignés par des références identiques. Comme on le voit en se reportant aux figures 1 à 3 conjointement, l'inducteur 1 est un stator de moteur linéaire refermé sur lui-même, constitué à cet effet de deux parties hémi-tubulaires égales indépendantes 2a et 2b, (les demi-coquilles). Chaque demi-coquille comporte trois pôles saillants bobinés 3 dont la face polaire 4 est tournée vers l'intérieur, ces pôles magnétiques, en tôles de fer doux empilées assemblées, étant classiquement reliés entre eux par une culasse hémi-tubulaire périphérique externe 5 a, 5b. L'ensemble est dimensionné pour que les deux culasses appariées viennent s'abouter dans le plan de jonction J lorsque l'inducteur est en position de travail fermée montrée sur les figures 1 et 2. Une calotte 7a, 7b, également de forme hémi-tubulaire correspondante coiffe intérieurement les faces polaires de chaque demi-coquille et forme, une fois l'inducteur en position fermée, un écran de protection thermique 7 qui entoure à faible distance la busette de coulée. Cette protection thermique est souhaitable pour les enroulements électriques 3 de l'inducteur à l'égard du rayonnement émis par la busette de coulée 8 montrée sur la figure 3 et canalisant le flux de métal en fusion vers la lingotière. Des précisions sur la constitution possible de cet écran seront données par la suite. L'enroulement électrique 6 de chaque pôle bobiné 3 est relié à une phase d'une alimentation électrique triphasée (non représentée) destinée à fournir le courant primaire de l'inducteur. L'inducteur étant en position fermée, un pôle saillant quelconque de l'une des demi-coquilles 2a fait diamétralement face à un pôle saillant de l'autre demi- coquille 2b. Ces deux pôles forment une "paire de pôles" en ce sens qu'ils sont tous deux connectés à la même phase de l'alimentation électrique, mais en opposition (par exemple via un sens de bobinage différent) de manière à ce que, à chaque instant, leurs faces actives soient de signes contraires. Cette condition est nécessaire pour que le champ magnétique produit soit de type traversant. Les pôles 3 et la culasse 5a,5b de retour du flux magnétique sont feuilletés en tôles Fe-Si à grains orientés d'épaisseur initiale 0.3 mm de manière à minimiser les pertes d'hystérésis. Leur hauteur opérationnelle (hauteur de la face active 4) est comprise entre 50 (valeur minimale) et 500 mm, fonction de la place disponible entre le répartiteur et le haut de la lingotière entre lesquels l'inducteur prendra place. Leur diamètre interne (diamètre de l'entrefer) est de l'ordre du diamètre externe de la busette de coulée augmenté d'une dizaine de mm à peine pour préserver une séparation mais de manière à assurer le meilleur couplage inductif possible. Les enroulements primaires 6 sont constitués d'un grand nombre (plusieurs centaines) de spires en fils de cuivre de très faible diamètre supportant des densités de courants élevées (>10 A/mm ). Ils sont munis en leur sein d'extracteurs de chaleur en cuivre refroidis par circulation d'eau (non représentés) . Ces bobinages sont alimentés en courants triphasés à moyenne fréquence allant de 50 Hz à 600 Hz. Dans la technologie proposée, on notera que fonctionner à fréquence élevée, supérieure à 50 ou 60 Hz, permet, à intensité constante des courants, d'augmenter le couple moteur que les forces électromagnétiques exercent sur le métal s'écoulant dans la busette. Toutefois, cette option nécessite l'utilisation de convertisseur de fréquences contrairement au fonctionnement à la fréquence du réseau (50 ou 60 Hz). Comme le montre le diagramme de la figure 5, ce moteur statique que constitue l'inducteur 1 peut générer dans son entrefer occupé par la busette un champ électromagnétique transverse (dit traversant) de forte intensité (entre 1000 et 1500 gauss) pour des valeurs faibles des courants inducteurs (quelques dizaines d'ampères). Ce champ, comme on le voit sur le diagramme, est quasiment uniforme dans la partie centrale de l'entrefer. Cette caractéristique essentielle de l'invention permet de générer dans le métal liquide un champ de forces uniformément décroissant de la paroi jusqu'au centre, comme montré sur le diagramme de la figure 6. Ceci permet, comme le montre clairement également la carte de vitesse de la figure 4, de mettre en rotation le métal liquide avec une vitesse qui reste importante même dans la partie axiale de la busette. Cette spécificité est nécessaire pour éviter une trop forte dépression dans la partie centrale de la busette où le métal aurait tendance alors à "fuir" et à subir une forte accélération verticale descendante, annulant ainsi une partie de l'effet bénéfique de la mise en rotation. Comme il apparaît clairement sur la figure 2, c'est grâce à la forme retrécie des dents magnétiques radiaux 3 à leur extrémité libre 4 (les faces polaires) que, à tout moment, les lignes de force du champ magnétique dans l'entrefer relient pour l'essentiel deux pôles diamétralement opposés et que seule une partie résiduelle du champ boucle entre pôles voisins. Ce résultat, indispensable à la mise en oeuvre de l'invention, est obtenu, en dépit de la compacité nécessaire de l'inducteur, grâce à cette forme retrécie de l'extrémité des pôles, qui fait que malgré leur rapprochement mutuel à mesure que l'on avance vers le centre, la distance qui sépare leurs extrémités libres deux à deux reste suffisante pour éviter un pontage important des lignes de champ entre elles. C'est cela qui, dans le cas d'inducteur compact de petite taille, est garant de la forte intensité relative du champ magnétique dans l'axe (cf. fig. 5), autrement-dit du caractère impérativement "traversant" de ce champ sans lequel l'invention ne produit pas les effets recherchés. Comme on le voit sur la figure 1 et plus visiblement encore sur la figure 2, ce rétrécissement de forme des dents radiales 3 est obtenue grâce à un prédécoupage en biseau 12 des extrémités des tôles à empiler pour former les former. L'angle du biseau est à ajuster en fonction du diamètre externe de la busette à entourer. On retiendra toutefois que la face polaire 4 ne doit pas être, en surface, inférieure à la moitié de la section droite de la dent 3 et que le début du biseau de rétrécissement 12 sur le corps de la dent peut s'initier qu'au deux tiers de la longueur. Il n'est pas nécessaire de débuter avant et c'est même souhaitable de le faire le plus tard possible afin de maximiser la masse magnétique de l'nducteur. En alimentant l'inducteur par un circuit résonant, l'intensité des courants primaires peut être fortement augmentée. La technique proposée permet en effet, dans une large gamme d'intensité des courants primaires, d'augmenter très fortement l'intensité du champ électromagnétique dans l'entrefer, en augmentant l'intensité de ces courants à des valeurs bien au delà de l'intensité seuil correspondante à la saturation magnétique de la culasse 5. Celle-ci permet de canaliser les lignes de champ magnétique et d'augmenter, dans l'entrefer du moteur, l'intensité de ce champ magnétique jusqu'à ce que ce dernier atteigne sa valeur de saturation dans la culasse. Au delà de cette valeur seuil, c'est le champ magnétique généré, par l'inducteur directement dans l'air qui contribue à l'augmentation de l'intensité du champ dans l'entrefer du moteur. En fonctionnement, l'inducteur est très proche (à 5 mm environ de distance) de la busette de coulée 8 dont la température extérieure est de l'ordre de 1100 à 1200°C. Sa protection thermique, vis-à-vis du rayonnement émis par la busette, est alors assurée par l'écran segmenté en cuivre 7, de fine épaisseur, refroidi par circulation d'eau et transparent au champ électromagnétique grâce à cette segmentation. La constitution de l'inducteur 1 en deux parties hémi-tubulaires indépendantesThe present invention relates to the continuous casting of metals, steel in particular, implementing a submerged casting nozzle which is immersed in a mold placed underneath. More specifically, the invention relates to the axial rotation of the liquid metal in transit in such a nozzle between the tundish and the mold. It is known that the axial rotation of the metal already within the casting nozzle is a recognized means for controlling the flows in the mold by modifying the distribution of the gas bubbles and inclusions present in the liquid metal before it arrives in the mold. It is thus possible to: reduce or even eliminate the inclusions deposits along the inner wall of the nozzle and, in the case of a nozzle with lateral outlet openings for the casting of slabs, at its gills and its bottom bowl; - greatly reduce the penetration depth of the gas bubbles and inclusions in the liquid well of the product being cast, thus also the risk of their entrapment on the intrados face of the products cast on a bent machine - reduce the speed of circulation of the liquid metal under the meniscus as well as the level fluctuations thereof; - Limit the flow instabilities, like jets swings in the mold by generating a "gyroscopic" effect on the flows in the nozzle. The rotation of the flows in the pouring nozzle thus appears as an effective means for combating the appearance of surface appearance defects, such as blistering and exfoliations, on cold-lined sheets of steel grades for application. automotive and packaging steels. This technique therefore enables the reduction of the writing operations on continuously cast slabs (reduction or even elimination of surface defects on exfoliation-type sheets), the elimination of downgrades and disputes for blistered defects, as well as the increase in productivity. machines by lengthening sequences and increasing casting speeds. The rotating of the liquid metal in the pouring nozzle has already been proposed using different types of actuators. Two types of actuators can be schematically distinguished: "passive" actuators and "active" ones. The "passive" actuators are, among other things, the design modifications of the inner wall of the nozzle (for example: spirals), the members such as the helix, the internal helical nozzle, etc. which are implanted in the body of the nozzle itself. , or the modifications of the upper portion of the nozzle at the junction with the distributor (for example: acceleration cone) or the modifications of the actual body for regulating the metal flow in the nozzle. The major disadvantages of this type actuators are to generate a rotation speed directly dependent on the metal flow passing through the nozzle and to constitute preferred sites of deposits of inclusions in the nozzle, resulting in a potential increase in the risk of clogging. The "active" actuators are essentially of electromagnetic nature: a polyphase type static annular electromagnetic inductor surrounds the nozzle at a small distance over part of its length and generates a magnetic field rotating around the casting axis intended to drive in axial rotation with him the liquid metal present in the nozzle. Examples are described in JP 06 023498 or JP 07 108355 or JP 07 148561. However, the electromagnetic devices heretofore proposed are, for the most part, based on the tangential rotating field linear stators technology operating at low or very low frequency (<10 Hz). These devices have the disadvantages of: generating rotational speeds that are often too low, given the current frequencies used, to obtain the desired effects (for example, at 4 Hz three-phase usable for an internal nozzle diameter of 80 mm, the maximum theoretical rotation speed is 80 rpm), - generating in the liquid metal a highly concentrated force field close to the inner wall of the nozzle, which has the consequence of creating a zone of strong depression in the central portion of the nozzle where the metal is then accelerated in the downward vertical direction; - must work with high current (> 300-500 A), which leads to large devices in order to ensure their cooling, so not easy to implement on a continuous casting machine and more require the use of very expensive electric generator. The others are magnetic field through, so salient poles wound to a pair of poles by phases facing one another on either side of the axis of the nozzle. The invention falls within this category. They make it possible to overcome some of the disadvantages mentioned above, in particular the phenomenon of central depression. However, the smallness of the location combined with a necessarily high electrical power installed, as well as the desired reduction of the air gap by bringing the protruding inward polar tooth protruding beyond the winding and the nozzle to maximize the electromagnetic coupling. , inevitably lead in fact to a deterioration of the energetic efficiency at the same time as to a certain degree of possible disorganization of the rotational movements of the metal following, in particular, risks of parasitic bridging of the magnetic flux between too close poles belonging to phases different from the power supply. The object of the present invention is to propose a solution for an electromagnetic rotation of the liquid metal within a casting nozzle which does not have the drawbacks of known solutions. To this end, the subject of the invention is a continuous casting plant for metals, in particular steel, in which the submerged nozzle through which the molten metal to be poured arrives in the mold from a pouring distributor located above is surrounded by an electromagnetic annular magnetic field inductor rotating around the casting axis for driving in axial rotation with it the molten metal, said inductor being of polyphase type with a magnetic field having a pair of poles per phase and each pole of which is formed by an electric winding wound around an inwardly projecting pole tooth terminating in a polar face disposed opposite and in proximity to the nozzle, the pole teeth being interconnected by a bolt external magnetic magnetic flux closing device, characterized in that each polar tooth has a lateral narrowing (a bevel for example) at the end of its projecting portion, which increases the distance separating the polar faces between them. According to an advantageous variant, the annular inductor is formed in two pivotally articulated half-shells that can close around the nozzle. As will doubtless be understood, the invention implements a so-called "through" magnetic field, that is to say passing through the axis of the nozzle without noticeable weakening of its intensity between the edge and the center of that -this. Due to the technological base chosen, namely that with a pair of poles per phase of the power supply supplying a polyphase annular inductor with wound salient poles distributed around the nozzle, the rotating magnetic field produced is of the desired "through" type . In other words, at each instant, the casting axis is at the center of the air gap of the inductor and the produced field prospers in this gap through the casting axis for, from a given magnetic pole, join the magnetic pole paired opposite sign located opposite and not next to it as it would be the case with an inductor with distributed poles or several pairs of poles per phase. It is recalled that this type of technology is not new in itself. It is even quite widely used for the rotation of the liquid metal cast, not in a nozzle, but in the mold itself, so in the case of inductors to rotate (the liquid metal column) much larger apparent diameter than that of the metal jet in the nozzle and with a correspondingly much lower rotational angular velocity requirement (see for example USP 4,462,458). However, contrary to popular belief, it turns out that the transfer of this technology from the mold to the pouring nozzle can, without necessarily consenting to a marked decline in installed power, be accompanied by a reduction in size of the inductor compatible with the last assembly around and as close to a casting nozzle provided that one preserves the character "through", in any case essentially "through", the magnetic field produced, and without harming its necessary cooling. However, it is precisely here that lies the idea underlying the invention: to achieve, without penalizing the performance of the inductor, preserve this character "crossing" the field despite the compactness of the inductor and the minimization of the gap by agreeing to a slight loss of magnetic mass localized at selected locations of the salient poles, namely the edges of the active faces, to counter-carrage the natural tendency of the field magnetic to propagate in the gap according to the least reluctant paths by looping between neighboring poles close to each other. Tests performed on steel have confirmed the ability of such an inductor to rotate the metal flowing in a submerged nozzle under casting conditions much more severe than those encountered in industrial bloom or slab machines. These tests were carried out with a nozzle of the straight type (single axial opening opening in the bottom) in which the metal flowed at an average speed of the order of 3.5 to 4.2 m / s, knowing that in a slab casting nozzle, the average flow rates are rather between 1.5 and 2.0 m / s. The invention will in any case be well understood and other aspects and advantages will become apparent from the following description given by way of exemplary embodiment and with reference to the attached drawing plates in which: - Figure 1 is a diagram representative, seen in cross section, the inductor in two butted half-shells provided with its internal heat shield bordering the gap; - Figure 2 is a diagram similar to the previous one but intended to show the propagation of the lines of force of the magnetic field through the gap as frozen at any given time of the operation of the inductor; FIG. 3 is a block diagram showing the articulation of the two half-shells constituting the inductor; FIG. 4 shows the map of the velocities of the liquid metal rotating within the casting nozzle under the effect of the magnetic field in a plane of cross section of the nozzle; FIG. 5 shows the evolution of the intensity B of the magnetic field in the air gap along a diameter D of the nozzle taken in a plane situated at half height of the inductor; FIG. 6 shows, in correspondence with the representation of FIG. 5, the correlative evolution of the magnetic force field F B along a diameter D of the nozzle according to a radial profile R and according to a orthoradial profile OR. In the figures, the same elements are designated by identical references. As can be seen with reference to FIGS. 1 to 3 together, the inductor 1 is a linear motor stator closed on itself, constituted for this purpose by two independent, equal semicubular portions 2a and 2b, shells). Each half-shell comprises three coiled protruding poles 3, the polar face 4 of which faces inwards, these magnetic poles, made of assembled stacked soft iron sheets, being conventionally connected to each other by an outer peripheral hemi-tubular yoke 5, 5b. The set is sized so that the two paired heads come together in the junction plane J when the inductor is in the closed working position shown in Figures 1 and 2. A cap 7a, 7b, also of corresponding hemi-tubular form internally cape the polar faces of each half-shell and form, once the inductor in the closed position, a thermal protection screen 7 which surrounds at a short distance the casting nozzle. This thermal protection is desirable for the electric windings 3 of the inductor with respect to the radiation emitted by the pouring nozzle 8 shown in FIG. 3 and channeling the flow of molten metal towards the mold. Details on the possible constitution of this screen will be given later. The electrical winding 6 of each coiled pole 3 is connected to a phase of a three-phase power supply (not shown) intended to supply the primary current of the inductor. With the inductor in the closed position, any protruding pole of one of the half-shells 2a is diametrically opposite a projecting pole of the other half-shell 2b. These two poles form a "pair of poles" in the sense that they are both connected to the same phase of the power supply, but in opposition (for example via a different winding direction) so that, at every moment, their active faces are of opposite signs. This condition is necessary for the magnetic field produced to be of the through type. The magnetic flux return poles 3 and 5a, 5b are laminated into grain-oriented Fe-Si plates having an initial thickness of 0.3 mm in order to minimize the hysteresis losses. Their operating height (height of the active face 4) is between 50 (minimum value) and 500 mm, depending on the space available between the distributor and the top of the mold between which the inductor will take place. Their internal diameter (diameter of the gap) is of the order of the outer diameter of the casting nozzle increased by a few tens of mm to preserve a separation but in order to ensure the best possible inductive coupling. The primary windings 6 consist of a large number (several hundred) of very small copper wire turns supporting high current densities (> 10 A / mm). They are provided within them water-cooled copper heat extractors (not shown). These coils are supplied with three-phase currents at medium frequency ranging from 50 Hz to 600 Hz. In the proposed technology, it will be noted that operating at a high frequency, greater than 50 or 60 Hz, makes it possible, at constant currents, to increase the current. motor torque that the electromagnetic forces exert on the metal flowing in the nozzle. However, this option requires the use of a frequency converter, unlike the operation at the mains frequency (50 or 60 Hz). As shown in the diagram of FIG. 5, this static motor constituting the inductor 1 can generate in its gap occupied by the nozzle a transverse electromagnetic field (said through) of high intensity (between 1000 and 1500 gauss) for low values. inductive currents (a few tens of amperes). This field, as seen in the diagram, is almost uniform in the central part of the gap. This essential characteristic of the invention makes it possible to generate in the liquid metal a field of forces uniformly decreasing from the wall to the center, as shown in the diagram of FIG. 6. This allows, as the speed chart also clearly shows. of Figure 4, to rotate the liquid metal with a speed that remains high even in the axial portion of the nozzle. This specificity is necessary to avoid a too strong depression in the central part of the nozzle where the metal would then tend to "leak" and undergo a strong downward vertical acceleration, thus canceling part of the beneficial effect of rotating . As clearly shown in FIG. 2, it is thanks to the shrunken shape of the radial magnetic teeth 3 at their free end 4 (the polar faces) that, at any moment, the lines of force of the magnetic field in the air gap connect essentially two diametrically opposed poles and only a residual part of the field loop between neighboring poles. This result, essential to the implementation of the invention, is obtained, despite the necessary compactness of the inductor, thanks to this shrunken shape of the end of the poles, which makes that despite their mutual rapprochement as we move towards the center, the distance between their free ends two to two remains sufficient to avoid significant bridging of the field lines between them. This is what, in the case of a small compact inductor, is a guarantee of the high relative intensity of the magnetic field in the axis (see Fig. 5), otherwise the imperatively "traversing" nature of this field without which the invention does not produce the desired effects. As seen in Figure 1 and more clearly in Figure 2, the shape of the radial teeth 3 is reduced by a pre-cut bevel 12 ends of the sheets to stack to form them. The angle of the bevel is to be adjusted according to the outer diameter of the nozzle to be surrounded. It should be noted, however, that the polar face 4 should not be less than half of the cross-section of the tooth on the surface 3 and that the beginning of the narrowing bevel 12 on the body of the tooth can be initiated only by two thirds of the length. It is not necessary to start before and it is even desirable to do it as late as possible to maximize the magnetic mass of the nducer. By supplying the inductor with a resonant circuit, the intensity of the primary currents can be greatly increased. The proposed technique makes it possible, in a wide range of intensity of the primary currents, to increase very strongly the intensity of the electromagnetic field in the gap, by increasing the intensity of these currents to values well beyond the threshold intensity corresponding to the magnetic saturation of the cylinder head 5. This allows to channel the magnetic field lines and increase, in the air gap of the motor, the intensity of this magnetic field until the latter reaches its saturation value in the cylinder head. Beyond this threshold value, it is the magnetic field generated by the inductor directly in the air which contributes to the increase of the intensity of the field in the gap of the engine. In operation, the inductor is very close (at about 5 mm distance) from the casting nozzle 8 whose outside temperature is of the order of 1100 to 1200 ° C. Its thermal protection, vis-à-vis the radiation emitted by the nozzle, is then provided by the segmented copper screen 7, of thin thickness, cooled by water circulation and transparent to the electromagnetic field through this segmentation. The constitution of the inductor 1 into two independent hemi-tubular parts
5 a et 5b permet aisément sa mise en place autour de la busette et son retrait à tout moment sans aucune modification du procédé standard de coulée. En se reportant à nouveau sur la figure 3, on voit que, pour être mis en place autour de la busette de coulée 8, l'inducteur est avantageusement maintenu par un support constitué de deux bras 9 articulés autour d'un axe pivoteur 10. Les bras sont animés par des vérins 11 qui assurent leur fermeture-ouverture et permettent d'exercer une force de contact suffisante (supérieure à 200 kgf) entre les culasses 5a et 5b des deux parties hémi-tubulaires 2a et5a and 5b allows easy installation around the nozzle and removal at any time without any modification of the standard casting process. Referring again to FIG. 3, it can be seen that, to be put in place around the casting nozzle 8, the inductor is advantageously held by a support consisting of two arms 9 articulated about a pivoting axis 10. The arms are driven by jacks 11 which ensure their closing-opening and allow to exert a sufficient contact force (greater than 200 kgf) between the yokes 5a and 5b of the two hemi-tubular parts 2a and
2b une fois celles-ci aboutées comme le montre la figure 1. D'une part, un contact étroit entre les culasses 5a et 5b est nécessaire à un bon bouclage des lignes de champ magnétique entre les deux parties constitutives de l'inducteur et donc à un bon rendement électromagnétique. D'autre part, une force importante de fermeture de deux hémi-tubes est nécessaire pour empêcher les vibrations qui seraient inévitablement générées par les forces électromagnétiques oscillantes. Il va de soi que l'invention ne saurait se limiter à l'exemple de réalisation décrit mais qu'elle s'étend à de multiples variantes et équivalents dans la mesure où est respectée sa définition donnée par les revendications jointes. 2b once abutted as shown in Figure 1. On the one hand, a close contact between the yokes 5a and 5b is necessary for a good looping of the magnetic field lines between the two constituent parts of the inductor and therefore at a good electromagnetic efficiency. On the other hand, a large force of closing two hemi-tubes is necessary to prevent the vibrations that would inevitably be generated by the oscillating electromagnetic forces. It goes without saying that the invention can not be limited to the embodiment described but that it extends to multiple variants and equivalents to the extent that is respected its definition given by the appended claims.

Claims

REVENDICATIONS 1) Installation de coulée continue des métaux, de l'acier en particulier, dans laquelle la busette immergée (8) par laquelle le métal en fusion à couler arrive en lingotière depuis un répartiteur situé au-dessus est entourée par un inducteur électromagnétique annulaire (1) à champ magnétique tournant autour de l'axe de coulée destiné à entraîner en rotation axiale avec lui le métal en fusion, ledit inducteur (1) étant du type polyphasé à champ magnétique traversant pourvu d'une paire de pôles (3) par phase et dont chaque pôle (3) est formé par un enroulement électrique bobiné (6) autour d'une dent polaire (3) saillante vers l'intérieur se terminant par une face polaire (4) disposée en regard de la busette (8), les dents polaires étant reliées entre elles par une culasse magnétique périphérique extérieure (5a, 5b) de fermeture du flux magnétique, installation caractérisée en ce que chaque dent polaire (3) présente, à l'extrémité de sa partie saillante, un rétrécissement latéral (12) qui augmente la distance séparant les faces polaires (4) entre elles.1) Continuous casting plant of metals, steel in particular, wherein the submerged nozzle (8) through which the molten metal to flow into the mold from a distributor located above is surrounded by an annular electromagnetic inductor (1) magnetic field rotating about the casting axis for driving in axial rotation with it the molten metal, said inductor (1) being of the polyphase type having a magnetic field having a pair of poles (3) per phase and of which each pole (3) is formed by a wound electrical winding (6) around an inwardly projecting pole tooth (3) terminating in a polar face (4) arranged facing the nozzle (8). ), the pole teeth being connected to each other by an outer magnetic peripheral yoke (5a, 5b) for closing the magnetic flux, an installation characterized in that each polar tooth (3) has, at the end of e its protruding part, a lateral narrowing (12) which increases the distance separating the polar faces (4) between them.
2) Installation de coulée continue selon la revendication 1 caractérisée en ce que la busette immergée (8) est une busette à ouies de sortie latérales.2) A continuous casting installation according to claim 1 characterized in that the submerged nozzle (8) is a nozzle with side outlet openings.
3) Installation de coulée continue selon la revendication 1 caractérisée en ce que l'inducteur (1) comporte à sa périphérie intérieure un écran de protection thermique (7) entourant la busette à distance.3) A continuous casting installation according to claim 1 characterized in that the inductor (1) has at its inner periphery a thermal protection screen (7) surrounding the remote nozzle.
4) Installation de coulée continue selon la revendication 1 caractérisée en ce que l'inducteur annulaire (1) est formé en deux demi-coquilles articulées pivotantes (2a, 2b). 5) Installation coulée continue selon la revendication 1 caractérisée en ce qu'elle comprend en outre un circuit électrique résonant dans lequel l'inducteur est monté en série avec une capacité réglable.4) A continuous casting installation according to claim 1 characterized in that the annular inductor (1) is formed in two pivoting articulated half-shells (2a, 2b). 5) Installation continuous casting according to claim 1 characterized in that it further comprises a resonant electrical circuit in which the inductor is connected in series with an adjustable capacity.
6) Installation de coulée continue selon la revendication 4, caractérisée en ce que l'inducteur (1) est monté à l'extrémité de bras-support (9) de maintien en position, ce bras support étant rétractable et pourvu de moyens commandés (11) actionnant chaque demi-coquille (2a, 2b) en pivotement. 6) A continuous casting installation according to claim 4, characterized in that the inductor (1) is mounted at the end of support arm (9) for holding in position, this support arm being retractable and provided with controlled means ( 11) actuating each half-shell (2a, 2b) pivotally.
EP04767284A 2003-06-17 2004-06-08 Continouos casting installation for the electromagnetic rotation of molten metal moving inside the nozzle Expired - Lifetime EP1633512B1 (en)

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PL04767284T PL1633512T3 (en) 2003-06-17 2004-06-08 Continouos casting installation for the electromagnetic rotation of molten metal moving inside the nozzle
SI200430240T SI1633512T1 (en) 2003-06-17 2004-06-08 Continouos casting installation for the electromagnetic rotation of molten metal moving inside the nozzle

Applications Claiming Priority (2)

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FR0307307A FR2856321B1 (en) 2003-06-17 2003-06-17 CONTINUOUS CASTING INSTALLATION FOR ELECTRO-MAGNETIC ROTATION OF LIQUID METAL IN TRANSIT IN THE CASTING BUSH
PCT/FR2004/001418 WO2005002763A2 (en) 2003-06-17 2004-06-08 Continouos casting installation for the electromagnetic rotation of molten metal moving inside the nozzle

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EP1633512A2 true EP1633512A2 (en) 2006-03-15
EP1633512B1 EP1633512B1 (en) 2007-01-10

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JP (1) JP4435781B2 (en)
KR (1) KR101004065B1 (en)
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DE (1) DE602004004270T2 (en)
ES (1) ES2279430T3 (en)
FR (1) FR2856321B1 (en)
PL (1) PL1633512T3 (en)
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Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006031964A1 (en) * 2004-09-13 2006-03-23 Energetics Technologies, L.L.C. Methods and facilities for suppressing vortices arising in tundishes or ladles during their respective discharge
FR2894167A1 (en) * 2005-12-06 2007-06-08 Usinor Sa EQUIPMENT FOR CONTINUOUS METAL CASTING DISTRIBUTION CASTING
ATE504374T1 (en) 2008-05-30 2011-04-15 Abb Ab CONTINUOUS CASTING MACHINE
CN103203450A (en) * 2013-03-20 2013-07-17 河北三方电气设备有限公司 Electromagnetic rotational flow water gap for continuous casting
CN103706772A (en) * 2013-12-20 2014-04-09 鞍钢股份有限公司 Device and method for slowing down impact depth of small casting blank molten steel
CN105268935B (en) * 2014-06-10 2017-10-20 东北大学 A kind of two-flap type submersed nozzle electromagnetic eddy flow device and its support meanss
KR101934495B1 (en) * 2014-06-10 2019-01-02 노스이스턴 유니버시티 Continuous casting method and device with electromagnetic swirling nozzle
CN105195726A (en) * 2014-06-11 2015-12-30 鞍钢股份有限公司 Device and method for slowing down negative pressure of long nozzle and impact force of molten steel
CN104128598B (en) * 2014-07-30 2016-04-20 河北三方电气设备有限公司 A kind of continuous casting mouth pipe swirl-flow devices
EP3363560A1 (en) * 2017-02-20 2018-08-22 ABB Schweiz AG A method and stirring system for controlling an electromagnetic stirrer
CN108421971B (en) * 2018-01-09 2024-02-13 武汉科技大学 Double-sawtooth anti-nodulation device for outlet of continuous casting tundish
US11478979B2 (en) * 2018-12-05 2022-10-25 Xerox Corporation Apparatus and method for variable magnetic alignment in fused deposition modeling (FDM) magnets
KR102440267B1 (en) * 2021-01-04 2022-09-06 한주금속(주) Two-segment electromagnet reaction reactor diecasting apparatus and diecasting method using the same
CN114029463A (en) * 2021-11-25 2022-02-11 山东钢铁股份有限公司 Method for solving segregation of large round billet of special steel

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2828160B2 (en) * 1978-06-23 1981-04-30 Aeg-Elotherm Gmbh, 5630 Remscheid Electromagnetic stirring device for continuous casting plants
FR2448247A1 (en) * 1979-01-30 1980-08-29 Cem Comp Electro Mec ELECTROMAGNETIC INDUCTOR FOR PRODUCING A HELICOIDAL FIELD
JPS5671563A (en) * 1979-11-15 1981-06-15 Sumitomo Metal Ind Ltd Continuous casting method
FR2502996A1 (en) * 1981-04-03 1982-10-08 Rotelec Sa ROTATING FIELD ELECTROMAGNETIC INDUCTOR AND CONTINUOUS CASTING LINGOTIERE EQUIPMENT FOR METALS THEREOF
JPS61115654A (en) * 1984-11-10 1986-06-03 Shinko Electric Co Ltd Continuous casting device
FR2613647B1 (en) * 1987-04-13 1990-11-16 Alsthom ELECTROMAGNETIC MIXING OF LIQUID METAL FOR CONTINUOUS CASTING LINE
JPH0623498A (en) * 1992-07-10 1994-02-01 Sumitomo Heavy Ind Ltd Device for controlling supply of molten steel in continuous casting
JP3186012B2 (en) * 1993-09-28 2001-07-11 株式会社神戸製鋼所 Pouring nozzle for continuous casting and continuous casting method
JPH07108355A (en) * 1993-10-08 1995-04-25 Kobe Steel Ltd Electromagnetic stirrer
JP2000052006A (en) * 1998-08-13 2000-02-22 Mitsubishi Heavy Ind Ltd Equipment and method for continuous casting of metallic pieces

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2005002763A2 *

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WO2005002763A3 (en) 2005-03-17
CA2529384C (en) 2010-03-30
KR20060019594A (en) 2006-03-03
EP1633512B1 (en) 2007-01-10
JP4435781B2 (en) 2010-03-24
FR2856321A1 (en) 2004-12-24
US20060124272A1 (en) 2006-06-15
CN100406165C (en) 2008-07-30
SI1633512T1 (en) 2007-06-30
DE602004004270T2 (en) 2007-05-31
CA2529384A1 (en) 2005-01-13
KR101004065B1 (en) 2010-12-27
DE602004004270D1 (en) 2007-02-22
PL1633512T3 (en) 2007-06-29
ES2279430T3 (en) 2007-08-16
WO2005002763A2 (en) 2005-01-13
FR2856321B1 (en) 2006-05-26
JP2006527661A (en) 2006-12-07
CN1809435A (en) 2006-07-26

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