EP0229589A1 - Device and process for continuous casting of metals - Google Patents

Device and process for continuous casting of metals Download PDF

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Publication number
EP0229589A1
EP0229589A1 EP86810520A EP86810520A EP0229589A1 EP 0229589 A1 EP0229589 A1 EP 0229589A1 EP 86810520 A EP86810520 A EP 86810520A EP 86810520 A EP86810520 A EP 86810520A EP 0229589 A1 EP0229589 A1 EP 0229589A1
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EP
European Patent Office
Prior art keywords
screen
coolant
counter screen
counter
inductor
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
EP86810520A
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German (de)
French (fr)
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EP0229589B1 (en
Inventor
Raoul Sautebin
Jean-Claude Weber
Carlo Alborghetti
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Alcan Holdings Switzerland AG
Original Assignee
Alusuisse Holdings AG
Schweizerische Aluminium AG
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Application filed by Alusuisse Holdings AG, Schweizerische Aluminium AG filed Critical Alusuisse Holdings AG
Priority to AT86810520T priority Critical patent/ATE49361T1/en
Publication of EP0229589A1 publication Critical patent/EP0229589A1/en
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    • 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
    • B22D11/01—Continuous casting of metals, i.e. casting in indefinite lengths without moulds, e.g. on molten surfaces
    • B22D11/015—Continuous casting of metals, i.e. casting in indefinite lengths without moulds, e.g. on molten surfaces using magnetic field for conformation, i.e. the metal is not in contact with a mould

Definitions

  • the invention relates to a device for contactless, vertical downward casting of metals in an alternating electromagnetic field, with an inductor, a coolant box with a device for supplying a coolant to the surface of the cast strand and an electrically conductive, non-ferromagnetic, tapered downward screen above the level defined by the lowest inductor lower edges.
  • molten metal is poured onto a start-up base attached within an inductor loop.
  • the approach floor is lowered at the specified speed.
  • High-frequency alternating current in the inductor generates an electromagnetic force field which limits the metal melt introduced horizontally within the inductor in a form which is essentially determined by the inner contours of the inductor loop.
  • a coolant for example water
  • the near-surface layer of the sinking strand rapidly solidifies.
  • the screen for example made of stainless steel, also designed as a loop, attached.
  • a major advantage of the electromagnetic over the conventional continuous casting plants is the much more uniformly formed surface of the cast strand, which is free of cold running, exudation and surface segregation, so that in most cases there is no need to overcut it.
  • DE-C-2 848 808 describes a mold which, by means of the special shape of the inductor, prevents concavity in the case of wide ingots.
  • EP-B-0 015 870 proposes a fine regulation of the coolant impingement angle and impingement range by a controlled deflection of the coolant jet in order to be able to optimally adapt the solidification conditions to the different casting alloys and casting speeds.
  • EP-B-062 606 in order to avoid a convex curvature of the strand base due to non-stationary cooling conditions in the sprue phase, a deflection surface with recesses that can be moved parallel to the cast strand axis is provided, which is inserted into the path of the coolant at least in the sprue phase.
  • EP-B-0 082 810 describes a further method for reducing the curvature of the strand foot that occurs when the strand is cooled too abruptly.
  • the coolant becomes a sub at least during the pouring phase stamped admixed, which emits a gas as a decomposition product when it hits the hot strand surface, which forms an insulating film there to reduce heat flow.
  • EP-B-0 109 357 describes the construction of an electromagnetic continuous casting mold which can be adjusted to different casting cross sections without impairing the dimensional accuracy of the casting contour.
  • the electromagnetic force field emanating from the inductor stimulates a melt circulation in the liquid head of the cast strand, which among other things Detachment of the oxide skin can cause. In sensitive cases, this leads to an impairment of the solidification conditions and the melt quality in the area of the solidifying strand surface, which manifests itself, for example, in an accumulation of oxide inclusions, in longitudinal folds and in such surface defects which only occur in the form of surface slate, looper lines and the further processed material similar things emerge. With such casting strands, the surface usually has to be milled over, so that the general advantages of electromagnetic casting cannot be fully exploited.
  • the invention is based on the object of creating a device of the type mentioned at the outset by means of which the surface quality of the casting strand and the products produced therefrom is improved, and in particular the melt circulation in the liquid head of the casting strand can be reduced.
  • an electrically conductive, non-ferromagnetic counter-taper which tapers upwards is arranged in the casting direction at a distance from the screen which is at least 2 mm and at most the height of the inductor. Screen-to-screen distances of more than the inductor height do not contribute to the desired effect. Distances of less than 2 mm hinder the general function of the continuous caster.
  • the counter screen must be attached to the other tele of the continuous casting system in an electrically insulated manner.
  • the counter screen is arranged as a non-closed loop around the cast strand and the open ends are connected to an AC power source.
  • the counter-shield loop can also be divided into several non-connected sections which are individually connected at their ends to AC sources. The electromagnetic alternating field emanating from these currents, in cooperation with the alternating field emanating from the inductor, produces liquid heads of the cast strand which are opposed to the eddy forces. This reduces the intensity of the melt circulation.
  • the object is achieved according to the invention by casting in a device according to the invention and reducing the melt circulation in the liquid head of the cast strand, at least in the stationary casting phase.
  • the melt circulation should preferably not be significantly influenced by the counter screen and the inductor should enclose the melt without any noticeable restriction by the counter screen, but in the subsequent stationary casting phase, the counter screen must exert the circulation-reducing effect.
  • the counter screen for receiving a coolant is provided with a cavity. Circulating coolant is used to cool the counter screen.
  • a counter screen preferably has coolant passages that start from the cavity and are directed towards the cast strand surface.
  • the coolant of the counter screen can thus be used as additional cast strand cooling. In coordination with the usual cast strand cooling system starting from the coolant box, this enables an optimal, step-by-step configuration of the cooling and thus contributes to improving the surface quality.
  • the casting device is designed in such a way that the counter screen is vertically adjustable and the distance to the top screen is so is changeable with.
  • the counter screen is anchored vertically adjustable on the coolant box.
  • Dielectric coolant flow baffles are placed on the vertically adjustable counter screen at selected points, which project vertically above the counter screen by a height that corresponds at most to the distance of the screen from the counter screen. This means that the coolant supply can also be changed locally by adjusting the counter screen.
  • the locations of the counter screen are selected according to those locations of the cast strand circumference that have a lower cooling requirement, for example the corner areas in the case of continuous cast ingots with a rectangular cross section.
  • a device is within the scope of the invention in which the screen is rigidly connected to the counter screen via at least one dielectric intermediate piece.
  • the intermediate piece can extend over the entire horizontal circumference of the counter screen and can essentially be broken only by coolant passage openings.
  • the counter screen forms a loop around the cast strand, which is not closed, but is interrupted by electrically non-conductive sections. These sections are intended to be short and can also be formed, for example, by an air gap between the counter-shield parts.
  • This counter screen is with movable, electrically conductive To provide contact elements, which in one position electrically bridge the non-conductive sections and can thus close the counter-shield loop. These bridging contact elements can be designed, for example, like the clamping devices described in EP-B-109 357.
  • An alternative method of influencing the action of the counter screen in the context of the invention is to start with a casting device in which the counter screen is interrupted by electrically non-conductive sections and which has movable, electrically conductive contact elements which can assume a position in which the bridged non-conductive sections and the counter-shield loop is closed.
  • the contact elements In the pouring phase, at least one contact element is in the open position so that the loop is not closed and the counter screen does not carry any eddy currents induced by the inductor.
  • the contact elements In the stationary phase, the contact elements must then be brought into the closed position so that the counter screen has its full effect on the melt circulation in the head of the Cast strand unfolded. This method offers the possibility of dispensing with vertical adjustability of the counter loop.
  • a counter-shield which forms a loop interrupted at one or more points.
  • the ends of these loop sections are connected in pairs, at least in the stationary phase, to an alternating current source which has the same frequency as the inductor current and the alternating electromagnetic field emanating from it.
  • Such a current fed directly into the counter-shield loop enables an optimal setting of the counter-shield effect on the melt circulation in the cast strand head.
  • a method according to the invention has proven to be particularly suitable here, in which a phase shift of 150 to 180 ° is set in the stationary phase between the current fed from the AC power source in the counter-shield and the current flowing in the inductor.
  • the amplitude of the counter-shield current should be less than the amplitude of the inductor current.
  • a preferred embodiment of this method is to let a liquid emerge from the coolant box sen, which - for example as described in EP-B-0 082 810 - has been admixed with a substance which releases a gas when it strikes the strand surface, for example nitrogen or carbon dioxide, which forms an insulating film.
  • a substance which releases a gas when it strikes the strand surface for example nitrogen or carbon dioxide, which forms an insulating film.
  • the method according to the invention is particularly suitable for the continuous casting of aluminum alloys with a magnesium content of at least 2%.
  • this process has brought about a decisive improvement in the strand surface, so that thin strips for the manufacture of beverage can lids, which have the undesirable surface slate only to an extremely small extent, can be produced from rolled bars produced in this way without over-milling.
  • the electromagnetic continuous casting installation shown in FIGS. 1 to 4 has an inductor 1 which is hollow for internal cooling.
  • the inductor 1 is embedded on one side in a coolant box 3.
  • the coolant (not shown) circulates in this coolant box 3 and is supplied to the surface of the cast strand 4 by means of a device.
  • the screen 2 is attached to the coolant box 3. Its lower edge is about a third of the height of the inductor 1 lower than the upper edge of the inductor 1.
  • Below the cooling box 3, a counter screen 5 is arranged. It is provided with a cavity for receiving a coolant (not shown).
  • the medium circulating therein cools the counter screen 5; in addition, it emerges from the coolant passages 6, which are directed toward a deeper zone of the surface of the cast strand 4.
  • the counter screen 5 which tapers upwards at an angle of 20 ° (should be: 10 to 45 °) lies with its upper edge higher than the lower edge of the inductor 1.
  • the distance 9 of this upper edge from the lower edge of the Screen 2 is about 45% of the height of inductor 1, which has a height of 60 mm.
  • the counter screen 5 is vertically adjustable on the coolant box 3 by means of a plate fastened by anchoring (not shown).
  • the distance 9 can hereby be varied between 2 and 60 mm.
  • the continuous casting installation shown in FIG. 2 combines two further devices which serve to influence the action of the counter screen 5 on the liquid head of the casting strand 4.
  • the counter screen 5 is interrupted in the area of at least one system corner by a gap as a non-conductive section 7.
  • a schematically drawn, electrically conductive contact element 8 is attached to the counter screen 5 on one side of the section 7 and bridges this section in a closed position in which the contact element 8 on the other side of the section 7 connects to the counter screen 5 in an electrically conductive manner. If no induced current is to flow in the counter screen 5 in the pouring phase, the contact element 8 is brought into a position which does not represent a bridging of the section 7.
  • FIG. 3 shows an alternative embodiment of the continuous casting installation shown in FIG. 1.
  • the counter screen 5 with the screen 2 is rigid via a dielectric Intermediate piece 11 connected. This is provided with coolant passage openings which are arranged at a suitable distance along the circumference of the cast strand.
  • FIG. 4 again shows a continuous caster with a vertically adjustable counter screen 5.
  • the cross section runs through an area in the vicinity of a vertical edge of the cast strand 4.
  • a dielectric coolant flow baffle 13 is placed on the upper edge of the counter screen 5. After the transition to the stationary casting phase, this covers the distance 9 between the screen 2 and the counter screen 5 to three quarters and thus deflects a large part of the cooling liquid emerging from the cooling box 3.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Manufacture Of Alloys Or Alloy Compounds (AREA)
  • Preventing Corrosion Or Incrustation Of Metals (AREA)
  • Superconductors And Manufacturing Methods Therefor (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Powder Metallurgy (AREA)

Abstract

A device for contactless, vertically downwards continuous casting of metals in an electromagnetic alternating field, has an inductor and an electrically conductive, non-ferromagnetic screen that tapers downwards and features at a vertical distance 9 from this screen an electrically conductive, non-ferromagnetic counter screen that tapers upwards, the distance 9 between the said screen and counter screen being at least 2 mm, at most equal of the height of the inductor and in a continuous process which employs this device the circulation of the melt in the molten head of the ingot is reduced at least in the steady-state phase of casting. The process is particularly suitable for continuous casting aluminum alloys having a magnesium content of at least 2%.

Description

Die Erfindung betrifft eine Vorrichtung zum berührungslo­sen, vertikal abwärts gerichteten Stranggiessen von Metal­len im elektromagnetischen Wechselfeld, mit einem Induktor, einem Kühlmittelkasten mit einer Vorrichtung zur Zuleitung eines Kühlmittels auf die Oberfläche des Gussstranges und einem elektrisch leitenden, nicht-ferromagnetischen, nach unten sich verjüngenden Schirm oberhalb der durch die tiefstliegenden Induktorunterkanten definierten Ebene.The invention relates to a device for contactless, vertical downward casting of metals in an alternating electromagnetic field, with an inductor, a coolant box with a device for supplying a coolant to the surface of the cast strand and an electrically conductive, non-ferromagnetic, tapered downward screen above the level defined by the lowest inductor lower edges.

Zudem liegt im Rahmen der Erfindung ein Verfahren zum be­rührungslosen, vertikal abwärts gerichteten Stranggiessen von Metallen in einer solchen Vorrichtung, sowie eine An­wendung dieses Verfahrens.In addition, within the scope of the invention is a method for the contactless, vertically downward continuous casting of metals in such a device, and an application of this method.

Bei derartigen elektromagnetischen Stranggiessanlagen wird Metallschmelze auf einen innerhalb einer Induktorschleife angebrachten Anfahrboden gegossen. Der Anfahrboden wird mit vorgegebener Geschwindigkeit gesenkt. Hochfrequenter Wech­selstrom im Induktor erzeugt ein elektromagnetisches Kraft­feld, welches die eingeführte Metallschmelze innerhalb des Induktors horizontal in einer Form begrenzt, welche im we­sentlichen durch die Innenkonturen der Induktorschleife be­stimmt wird. Durch Beaufschlagung mit einem Kühlmittel, beispielsweise Wasser, erfolgt eine rasche Erstarrung der oberflächennahen Schicht des sinkenden Stranges. Innerhalb der Induktorschleife ist zur Anpassung der magnetischen Feldstärke an den metallostatischen Druck im flüssigen Teil des Gussstranges der beispielsweise aus rostfreiem Stahl bestehende Schirm, ebenfalls als Schleife ausgebildet, an­gebracht.In such electromagnetic continuous casting plants, molten metal is poured onto a start-up base attached within an inductor loop. The approach floor is lowered at the specified speed. High-frequency alternating current in the inductor generates an electromagnetic force field which limits the metal melt introduced horizontally within the inductor in a form which is essentially determined by the inner contours of the inductor loop. When a coolant, for example water, is applied, the near-surface layer of the sinking strand rapidly solidifies. Inside the inductor loop is to adapt the magnetic field strength to the metallostatic pressure in the liquid part of the cast strand, the screen, for example made of stainless steel, also designed as a loop, attached.

Ein wesentlicher Vorteil der elektromagnetischen gegenüber den konventionellen Stranggiessanlagen besteht in der we­sentlich gleichmässiger ausgebildeten Oberfläche des Guss­stranges, welche frei von Kaltlauf, Ausschwitzungen und Oberflächenseigerungen ist, so dass sich eine Ueberfräsung derselben in den meisten Fällen erübrigt.A major advantage of the electromagnetic over the conventional continuous casting plants is the much more uniformly formed surface of the cast strand, which is free of cold running, exudation and surface segregation, so that in most cases there is no need to overcut it.

Weitere Ausgestaltungen solcher elektromagnetischer Strang­giesskokillen dienen der allfälligen Korrektur von Plan­heitsfehlern und mangelhaften Erstarrungsbedingungen. Bei­spielsweise beschreibt die DE-C-2 848 808 eine Kokille, welche durch spezielle Formgebung des Induktors eine Konka­vität bei breiten Walzbarren verhindert. Die EP-B-0 015 870 schlägt eine feine Regulierung des Kühlmittel-Auftreffwin­kels und -Auftreffbereichs durch eine kontrollierte Umlen­kung des Kühlmittelstrahls vor, um damit die Erstarrungsbe­dingungen den verschiedenen Giesslegierungen und Giessge­schwindigkeiten optimal anpassen zu können. In der EP-B-­062 606 ist zur Vermeidung einer konvexen Wölbung des Strangfusses durch nicht-stationäre Kühlbedingungen in der Angiessphase eine parallel zur Gussstrangachse bewegbare Ablenkfläche mit Ausnehmungen vorgesehen, welche zumindest in der Angiessphase in die Bahn des Kühlmittels eingescho­ben wird. Die EP-B-0 082 810 beschreibt eine weitere Metho­de zur Verminderung der bei zu schroffer Abkühlung des Stranges auftretenden Wölbung des Strangfusses. Dabei wird dem Kühlmittel zumindest während der Angiessphase eine Sub­ stanz beigemischt, die beim Auftreffen auf die heisse Strangoberfläche ein Gas als Zersetzungsprodukt abgibt, welches dort einen den Wärmeabfluss vermindernden Isolier­film bildet.Further configurations of such electromagnetic continuous casting molds serve to correct any flatness errors and inadequate solidification conditions. For example, DE-C-2 848 808 describes a mold which, by means of the special shape of the inductor, prevents concavity in the case of wide ingots. EP-B-0 015 870 proposes a fine regulation of the coolant impingement angle and impingement range by a controlled deflection of the coolant jet in order to be able to optimally adapt the solidification conditions to the different casting alloys and casting speeds. In EP-B-062 606, in order to avoid a convex curvature of the strand base due to non-stationary cooling conditions in the sprue phase, a deflection surface with recesses that can be moved parallel to the cast strand axis is provided, which is inserted into the path of the coolant at least in the sprue phase. EP-B-0 082 810 describes a further method for reducing the curvature of the strand foot that occurs when the strand is cooled too abruptly. The coolant becomes a sub at least during the pouring phase stamped admixed, which emits a gas as a decomposition product when it hits the hot strand surface, which forms an insulating film there to reduce heat flow.

In der EP-B-0 109 357 wird der Aufbau einer elektromagneti­schen Stranggusskokille beschrieben, welche auf verschie­dene Gussquerschnitte eingestellt werden kann, ohne die Massgenauigkeit der Gusskontur zu beeinträchtigen.EP-B-0 109 357 describes the construction of an electromagnetic continuous casting mold which can be adjusted to different casting cross sections without impairing the dimensional accuracy of the casting contour.

Das vom Induktor ausgehende elektromagnetische Kraftfeld regt im flüssigen Kopf des Gussstranges eine Schmelzezir­kulation an, welche u.a. Ablösungen der Oxidhaut bewirken kann. In diesbezüglich empfindlichen Fällen führt dies zu einer Beeinträchtigung der Erstarrungsbedingungen und der Schmelzequalität im Bereich der erstarrenden Strangober­fläche, welche sich beispielsweise in einer Anhäufung von Oxideinschlüssen, in Längsfalten sowie in solchen Oberflä­chenfehlern äussert, welche erst beim weiterverarbeiteten Material in Form von Oberflächenschiefer, looper lines und ähnlichem hervortreten. Bei derartigen Giesssträngen muss die Oberfläche meist überfräst werden, wodurch die gene­rellen Vorzüge des elektromagnetischen Giessens nicht voll ausgenützt werden können.The electromagnetic force field emanating from the inductor stimulates a melt circulation in the liquid head of the cast strand, which among other things Detachment of the oxide skin can cause. In sensitive cases, this leads to an impairment of the solidification conditions and the melt quality in the area of the solidifying strand surface, which manifests itself, for example, in an accumulation of oxide inclusions, in longitudinal folds and in such surface defects which only occur in the form of surface slate, looper lines and the further processed material similar things emerge. With such casting strands, the surface usually has to be milled over, so that the general advantages of electromagnetic casting cannot be fully exploited.

Der Erfindung liegt angesichts dieser Gegebenheiten die Aufgabe zugrunde, eine Vorrichtung der eingangs genannten Gattung zu schaffen, mittels welcher die Oberflächenquali­tät des Giessstranges und der daraus hergestellten Produkte verbessert, sowie insbesondere die Schmelzezirkulation im flüssigen Kopf des Gussstranges vermindert werden kann.In view of these circumstances, the invention is based on the object of creating a device of the type mentioned at the outset by means of which the surface quality of the casting strand and the products produced therefrom is improved, and in particular the melt circulation in the liquid head of the casting strand can be reduced.

Weiter soll ein Verfahren geschaffen werden, welches beim berührungslosen, vertikal abwärts gerichteten Stranggiessen von Metallen die Oberflächenqualität verbessert.Furthermore, a method is to be created which improves the surface quality in the contactless, vertically downward casting of metals.

In bezug auf die Vorrichtung wird die Aufgabe erfindungsge­mäss dadurch gelöst, dass ein elektrisch leitender, nicht-­ferromagnetischer, nach oben sich verjüngender Gegenschirm in Giessrichtung in einem Abstand zum Schirm angeordnet ist, welcher mindestens 2 mm und höchstens die Höhe des In­duktors beträgt. Schirm-Gegenschirm-Abstände von mehr als der Induktorhöhe tragen nichts zur gewünschten Wirkung bei. Abstände von weniger als 2 mm behindern die generelle Funktion der Stranggiessanlage. Der Gegenschirm ist gegen die übrigen Tele der Stranggiessanlage elektrisch isoliert anzubringen.With regard to the device, the object is achieved according to the invention in that an electrically conductive, non-ferromagnetic counter-taper which tapers upwards is arranged in the casting direction at a distance from the screen which is at least 2 mm and at most the height of the inductor. Screen-to-screen distances of more than the inductor height do not contribute to the desired effect. Distances of less than 2 mm hinder the general function of the continuous caster. The counter screen must be attached to the other tele of the continuous casting system in an electrically insulated manner.

Während des Giessvorganges werden innerhalb des Gegen­schirms durch das Magnetfeld des Induktors Wirbelströme in­duziert, sofern der Gegenschirm um den Gussstrang eine elektrisch leitende geschlossene Schleife bildet. In einer anderen zweckmässigen Ausführung wird der Gegenschirm als nicht-geschlossene Schleife um den Gussstrang angeordnet und die offenen Enden an einer Wechselstromquelle ange­schlossen. Die Gegenschirmschleife kann hierbei auch in mehrere nicht in Verbindung stehende Abschnitte unterteilt sein, welche einzeln mit ihren Enden an Wechselstromquellen angeschlossen sind. Das von diesen Strömen ausgehende elektromagnetische Wechselfeld erzeugt in Zusammenwirkung mit dem vom Induktor ausgehenden Wechselfeld flüssigen Kopf des Gussstranges den Wirbelkräften entgegengesetzte Kräfte. Damit verringern sie die Intensität der Schmelze­ zirkulation.During the casting process, eddy currents are induced within the counter screen by the magnetic field of the inductor, provided the counter screen forms an electrically conductive closed loop around the cast strand. In another expedient embodiment, the counter screen is arranged as a non-closed loop around the cast strand and the open ends are connected to an AC power source. The counter-shield loop can also be divided into several non-connected sections which are individually connected at their ends to AC sources. The electromagnetic alternating field emanating from these currents, in cooperation with the alternating field emanating from the inductor, produces liquid heads of the cast strand which are opposed to the eddy forces. This reduces the intensity of the melt circulation.

In bezug auf das Verfahren wird die Aufgabe erfindungsge­mäss dadurch gelöst, dass in einer erfindungsgemässen Vor­richtung gegossen und zumindest in der stationären Giess­phase die Schmelzezirkulation im flüssigen Kopf des Gussstranges verringert wird.With regard to the method, the object is achieved according to the invention by casting in a device according to the invention and reducing the melt circulation in the liquid head of the cast strand, at least in the stationary casting phase.

In der Angiessphase soll die Schmelzezirkulation bevorzugt nicht wesentlich durch den Gegenschirm beeinflusst werden und der Induktor soll die Schmelze ohne spürbare Einschrän­kung durch den Gegenschirm einschliessen, in der anschlies­senden stationären Giessphase jedoch muss der Gegenschirm die zirkulationsverringernde Wirkung ausüben.In the pouring phase, the melt circulation should preferably not be significantly influenced by the counter screen and the inductor should enclose the melt without any noticeable restriction by the counter screen, but in the subsequent stationary casting phase, the counter screen must exert the circulation-reducing effect.

In einer besonders zweckmässigen Ausführung der Giessvor­richtung ist der Gegenschirm zur Aufnahme eines Kühlmittels mit einem Hohlraum versehen. Darin zirkulierendes Kühlmit­tel dient der Kühlung des Gegenschirms. Bevorzugt weist ein solcher Gegenschirm vom Hohlraum ausgehende, gegen die Gussstrangoberfläche gerichtete Kühlmitteldurchlässe auf. Damit kann das Kühlmittel des Gegenschirms als zusätzliche Gussstrangkühlung genutzt werden. In Abstimmung mit der üblichen, vom Kühlmittelkasten ausgehenden Gussstrangküh­lung ermöglicht dies eine optimale stufenweise Ausgestal­tung der Kühlung und trägt somit zur Verbesserung der Ober­flächenqualität bei.In a particularly expedient embodiment of the casting device, the counter screen for receiving a coolant is provided with a cavity. Circulating coolant is used to cool the counter screen. Such a counter screen preferably has coolant passages that start from the cavity and are directed towards the cast strand surface. The coolant of the counter screen can thus be used as additional cast strand cooling. In coordination with the usual cast strand cooling system starting from the coolant box, this enables an optimal, step-by-step configuration of the cooling and thus contributes to improving the surface quality.

In einer im Rahmen der Erfindung bevorzugten Ausführung ist die Giessvorrichtung so gestaltet, dass der Gegenschirm vertikal verstellbar und der Abstand zum oberen Schirm so­ mit veränderbar ist. In einer entsprechenden zweckmässigen Ausführung ist der Gegenschirm am Kühlmittelkasten vertikal verstellbar verankert.In a preferred embodiment within the scope of the invention, the casting device is designed in such a way that the counter screen is vertically adjustable and the distance to the top screen is so is changeable with. In a corresponding expedient embodiment, the counter screen is anchored vertically adjustable on the coolant box.

Auf dem vertikal verstellbaren Gegenschirm sind an ausge­wählten Stellen dielektrische Kühlmittelflussschikanen auf­gesetzt, welche den Gegenschirm vertikal um eine höchstens dem Abstand des Schirms vom Gegenschirm entsprechende Höhe überragen. Damit kann lokal durch das Verstellen des Ge­genschirms auch die Kühlmittelzufuhr geändert werden. Die Stellen des Gegenschirms werden entsprechend derjenigen Stellen des Gussstrangumfangs gewählt, welche einen ge­ringeren Kühlbedarf aufweisen, beispielsweise die Eckbe­reiche bei Stranggussbarren mit rechteckigem Querschnitt.Dielectric coolant flow baffles are placed on the vertically adjustable counter screen at selected points, which project vertically above the counter screen by a height that corresponds at most to the distance of the screen from the counter screen. This means that the coolant supply can also be changed locally by adjusting the counter screen. The locations of the counter screen are selected according to those locations of the cast strand circumference that have a lower cooling requirement, for example the corner areas in the case of continuous cast ingots with a rectangular cross section.

Alternativ zu den Ausführungsformen mit verstellbarem Ab­stand des Gegenschirms liegt im Rahmen der Erfindung eine Vorrichtung, bei welcher der Schirm mit dem Gegenschirm über mindestens ein dielektrisches Zwischenstück starr ver­bunden ist. Dabei kann sich das Zwischenstück über den ge­samten horizontalen Umfang des Gegenschirms erstrecken und im wesentlichen nur von Kühlmitteldurchtrittsöffnungen durchbrochen sein.As an alternative to the embodiments with adjustable spacing of the counter screen, a device is within the scope of the invention in which the screen is rigidly connected to the counter screen via at least one dielectric intermediate piece. In this case, the intermediate piece can extend over the entire horizontal circumference of the counter screen and can essentially be broken only by coolant passage openings.

Eine weitere erfindungsgemässe Lösung beinhaltet, dass der Gegenschirm um den Gussstrang eine Schleife bildet, welche nicht geschlossen ist, sondern durch elektrisch nichtlei­tende Abschnitte unterbrochen ist. Diese Abschnitte sollen kurz sein und können beispielsweise auch durch einen Luft­spalt zwischen den Gegenschirmteilen gebildet werden. Die­ser Gegenschirm ist mit beweglichen, elektrisch leitenden Kontaktelementen zu versehen, welche in der einen Lage die nichtleitenden Abschnitte elektrisch überbrücken und so die Gegenschirmschleife schliessen können. Diese überbrückenden Kontaktelemente können beispielsweise wie die in der EP-B-­109 357 beschriebenen Klemmvorrichtungen ausgestaltet sein.Another solution according to the invention includes that the counter screen forms a loop around the cast strand, which is not closed, but is interrupted by electrically non-conductive sections. These sections are intended to be short and can also be formed, for example, by an air gap between the counter-shield parts. This counter screen is with movable, electrically conductive To provide contact elements, which in one position electrically bridge the non-conductive sections and can thus close the counter-shield loop. These bridging contact elements can be designed, for example, like the clamping devices described in EP-B-109 357.

Als zweckmässige Art, die Wirkung des Gegenschirms im er­findungsgemässen Stranggiessverfahren zu beeinflussen, hat sich das Verändern des vertikalen Abstandes zwischen der untersten Kante des Schirms und der obersten Kante des Ge­genschirms erwiesen. Hierbei ist die Relation zwischen der Höhe des Induktors und des Schirmabstandes entscheidend. Zu guten Resultaten führt eine Einstellung des Abstandes in der Angiessphase auf mindestens die halbe und höchstens die ganze Höhe des Induktors und eine Verringerung dieses Ab­standes nach dem Uebergang in die stationäre Phase auf zwi­schen 2 mm und der halben Induktorhöhe.Changing the vertical distance between the bottom edge of the screen and the top edge of the counter screen has proven to be an expedient way of influencing the action of the counter screen in the continuous casting process according to the invention. The relationship between the height of the inductor and the distance between the shields is decisive. Setting the distance in the pouring phase to at least half and at most the entire height of the inductor and reducing this distance after the transition to the stationary phase to between 2 mm and half the inductor height lead to good results.

Eine alternative Methode, die Wirkung des Gegenschirms im Rahmen der Erfindung zu beeinflussen, besteht darin, von einer Giessvorrichtung auszugehen, bei welcher der Gegen­schirm durch elektrisch nichtleitende Abschnitte unterbro­chen ist und welche bewegliche elektrisch leitende Kontakt­elemente aufweist, die eine Position einnehmen können, in welcher die nichtleitenden Abschnitte überbrückt und die Gegenschirmschleife geschlossen ist. In der Angiessphase ist hierbei mindestens ein Kontaktelement in der offenen Position, sodass die Schleife nicht geschlossen ist und der Gegenschirm keine vom Induktor induzierten Wirbelströme führt. In der stationären Phase sind die Kontaktelemente dann in Schliesslage zu bringen, damit der Gegenschirm seine volle Wirkung auf die Schmelzezirkulation im Kopf des Gussstranges entfaltet. Dieses Verfahren bietet die Mög­lichkeit, auf eine vertikale Verstellbarkeit der Gegen­schleife zu verzichten.An alternative method of influencing the action of the counter screen in the context of the invention is to start with a casting device in which the counter screen is interrupted by electrically non-conductive sections and which has movable, electrically conductive contact elements which can assume a position in which the bridged non-conductive sections and the counter-shield loop is closed. In the pouring phase, at least one contact element is in the open position so that the loop is not closed and the counter screen does not carry any eddy currents induced by the inductor. In the stationary phase, the contact elements must then be brought into the closed position so that the counter screen has its full effect on the melt circulation in the head of the Cast strand unfolded. This method offers the possibility of dispensing with vertical adjustability of the counter loop.

In einer bevorzugten Methode zur Beeinflussung der Gegen­schirmwirkung wird ein Gegenschirm benutzt, der eine an einer oder mehreren Stellen unterbrochene Schleife bildet. Die Enden dieser Schleifenabschnitte sind zumindest in der stationären Phase paarweise an eine Wechselstromquelle an­geschlossen, welche dieselbe Frequenz wie der Induktorstrom und das von ihm ausgehende elektromagnetische Wechselfeld aufweist. Ein derart direkt in die Gegenschirmschleife ein­gespiesener Strom ermöglicht eine optimale Einstellung der Gegenschirmwirkung auf die Schmelzezirkulation im Guss­strangkopf. Als besonders geeignet hat sich hierbei ein er­findungsgemässes Verfahren erwiesen, bei dem in der statio­nären Phase zwischen dem von der Wechselstromquelle im den Gegenschirm eingespiesenen Strom und dem im Induktor flies­senden Strom eine Phasenverschiebung von 150 bis 180° ein­gestellt wird. Die Amplitude des Gegenschirmstroms soll kleiner als die Amplitude des Induktorstroms sein.In a preferred method for influencing the counter-shield effect, a counter-shield is used which forms a loop interrupted at one or more points. The ends of these loop sections are connected in pairs, at least in the stationary phase, to an alternating current source which has the same frequency as the inductor current and the alternating electromagnetic field emanating from it. Such a current fed directly into the counter-shield loop enables an optimal setting of the counter-shield effect on the melt circulation in the cast strand head. A method according to the invention has proven to be particularly suitable here, in which a phase shift of 150 to 180 ° is set in the stationary phase between the current fed from the AC power source in the counter-shield and the current flowing in the inductor. The amplitude of the counter-shield current should be less than the amplitude of the inductor current.

Im Rahmen der Erfindung liegt eine Verbesserung der Guss­strangoberfläche durch eine Verfeinerung der Abkühlbeding­ungen, indem zusätzlich zum Kühlstrahl aus dem Kühlmittel­kasten die Strangoberfläche in einer tieferen Zone mit ei­nem Kühlmittel beaufschlagt wird, das aus Kühlmitteldurch­lässen des Gegenschirms austritt.Within the scope of the invention is an improvement of the cast strand surface by a refinement of the cooling conditions, in addition to the cooling jet from the coolant box, the strand surface is acted upon in a deeper zone with a coolant which emerges from coolant passages of the counter screen.

Eine bevorzugte Ausführung dieses Verfahrens liegt darin, aus dem Kühlmittelkasten eine Flüssigkeit austreten zu las­ sen, welcher -- beispielsweise wie in der EP-B-0 082 810 beschrieben -- eine Substanz beigemischt wurde, die beim Auftreffen auf die Strangoberfläche ein Gas freisetzt, bei­spielsweise Stickstoff oder Kohlendioxid, welches ein Iso­lierfilm bildet. Zur besseren Kühlung in einer tieferen Zone bricht der dort auftreffende, aus den Kühlmitteldurch­lässen des Gegenschirms strömende Kühlmittelstrahl diese Isolierschichten auf.A preferred embodiment of this method is to let a liquid emerge from the coolant box sen, which - for example as described in EP-B-0 082 810 - has been admixed with a substance which releases a gas when it strikes the strand surface, for example nitrogen or carbon dioxide, which forms an insulating film. For better cooling in a deeper zone, the coolant jet that strikes there and flows out of the coolant passages of the counter screen breaks up these insulating layers.

Das erfindungsgemässe Verfahren eignet sich in besonderer Weise zum Stranggiessen von Aluminiumlegierungen mit einem Magnesiumgehalt von mindestens 2%. Insbesondere beim Gies­sen der Legierung AA 5182 hat dieses Verfahren eine ent­scheidende Verbesserung der Strangoberfläche gebracht, so­dass aus derart hergestellten Walzbarren ohne Ueberfräsung Dünnbänder zur Herstellung von Getränkedosendeckeln gefer­tigt werden können, welche den unerwünschten Oberflächen­schiefer nur in äusserst geringem Masse aufweist.The method according to the invention is particularly suitable for the continuous casting of aluminum alloys with a magnesium content of at least 2%. In particular when casting the alloy AA 5182, this process has brought about a decisive improvement in the strand surface, so that thin strips for the manufacture of beverage can lids, which have the undesirable surface slate only to an extremely small extent, can be produced from rolled bars produced in this way without over-milling.

Weitere Vorteile, Merkmale und Einzelheiten der Erfindung ergeben sich aus der nachfolgenden Beschreibung eines be­vorzugten Ausführungsbeispiels sowie anhand der Zeichnung; diese zeigt in

  • Figur 1 einen schematisierten Querschnitt durch einen Teil einer erfindungsgemässen Stranggiessvorrichtung mit Gussstrang, mit vertikal verstellbarem Gegenschirm,
  • Figur 2 eine schematisierte Schrägsicht auf eine erfin­dungsgemässe, rechteckige Stranggiessanlage, welche durch eine durch die Gussstrangachse verlaufende Ebene geschnitten ist,
  • Figur 3 einen schematisierten Querschnitt durch eine erfin­dungsgemässe Ausführungsform der Stranggiessvor­richtung mit starrer Verbindung zwischen Schirm und Gegenschirm,
  • Figur 4 einen schematisierten Querschnitt durch eine wei­tere Ausführungsform der erfindungsgemässen Strang­giessvorrichtung mit verstellbarem Gegenschirm mit aufgesetzter Kühlmittelflussschikane.
Further advantages, features and details of the invention result from the following description of a preferred exemplary embodiment and from the drawing; this shows in
  • FIG. 1 shows a schematic cross section through part of a continuous casting device according to the invention with a cast strand, with a vertically adjustable counter screen,
  • FIG. 2 shows a schematic oblique view of a rectangular continuous casting installation according to the invention, which is cut through a plane running through the axis of the cast strand,
  • FIG. 3 shows a schematic cross section through an embodiment of the continuous casting apparatus according to the invention with a rigid connection between the screen and counter screen,
  • FIG. 4 shows a schematic cross section through a further embodiment of the continuous casting device according to the invention with an adjustable counter screen with an attached coolant flow baffle.

Die in den Figuren 1 bis 4 dargestellte elektromagnetische Stranggiessanlage weist einen Induktor 1 auf, welcher zur inneren Kühlung hohl ausgebildet ist. Der Induktor 1 ist einseitig in einen Kühlmittelkasten 3 eingebettet. In die­sem Kühlmittelkasten 3 zirkuliert die -- nicht eingezeich­nete -- Kühlflüssigkeit, welche mittels einer Vorrichtung auf die Oberfläche des Gussstranges 4 zugeleitet wird. Am Kühlmittelkasten 3 ist der Schirm 2 befestigt. Seine untere Kante liegt etwa um einen Drittel der Höhe des Induktors 1 tiefer als die obere Kante des Induktors 1. Unterhalb des Kühlkastens 3 ist ein Gegenschirm 5 angeordnet. Er ist zur Aufnahme einer -- nicht eingezeichneten -- Kühlflüssigkeit mit einem Hohlraum versehen. Das darin zirkulierende Medium kühlt den Gegenschirm 5; zusätzlich tritt es aus den Kühl­mitteldurchlässen 6, welche auf eine tiefere Zone der Ober­fläche des Gussstrangs 4 gerichtet sind. Der sich nach oben mit einem Winkel von 20° (soll: 10 bis 45°) verjüngen­de Gegenschirm 5 liegt mit seiner oberen Kante höher als die untere Kante des Induktors 1. Der in Figur 1 eingezei­chnete Abstand 9 dieser oberen Kante von der unteren Kante des Schirmes 2 beträgt etwa 45 % der Höhe des Induktors 1, welcher eine Höhe von 60 mm aufweist. Diese Konfiguration entspricht der stationären Giessphase. Der Gegenschirm 5 ist mittels einer Platte vertikal verstellbar am Kühlmit­telkasten 3 durch eine -- nicht eingezeichnete -- Veranke­rung befestigt. Der Abstand 9 kann hiermit zwischen 2 und 60 mm variiert werden. Nebst dieser, vereint die in der Figur 2 dargestellte Stranggiessanlage zwei weitere Ein­richtungen, welche der Beeinflussung der Wirkung des Gegen­schirms 5 auf den flüssigen Kopf des Gussstrangs 4 dienen. Der Gegenschirm 5 ist in der Gegend mindestens einer Anla­genecke durch eine Lücke als nichtleitenden Abschnitt 7 unterbrochen. Ein schematisiert eingezeichnetes, elektrisch leitendes Kontaktelement 8 ist am Gegenschirm 5 auf der einen Seite des Abschnitts 7 befestigt und überbrückt die­sen Abschnitt in einer Schliesslage, in welcher das Kon­taktelement 8 auf der anderen Seite des Abschnitts 7 am Ge­genschirm 5 elektrisch leitend anschliesst. Soll in der An­giessphase im Gegenschirm 5 kein induzierter Strom flies­sen, wird das Kontaktelement 8 in eine Position gebracht, welche keine Ueberbrückung des Abschnitts 7 darstellt.The electromagnetic continuous casting installation shown in FIGS. 1 to 4 has an inductor 1 which is hollow for internal cooling. The inductor 1 is embedded on one side in a coolant box 3. The coolant (not shown) circulates in this coolant box 3 and is supplied to the surface of the cast strand 4 by means of a device. The screen 2 is attached to the coolant box 3. Its lower edge is about a third of the height of the inductor 1 lower than the upper edge of the inductor 1. Below the cooling box 3, a counter screen 5 is arranged. It is provided with a cavity for receiving a coolant (not shown). The medium circulating therein cools the counter screen 5; in addition, it emerges from the coolant passages 6, which are directed toward a deeper zone of the surface of the cast strand 4. The counter screen 5 which tapers upwards at an angle of 20 ° (should be: 10 to 45 °) lies with its upper edge higher than the lower edge of the inductor 1. The distance 9 of this upper edge from the lower edge of the Screen 2 is about 45% of the height of inductor 1, which has a height of 60 mm. This configuration corresponds to the stationary casting phase. The counter screen 5 is vertically adjustable on the coolant box 3 by means of a plate fastened by anchoring (not shown). The distance 9 can hereby be varied between 2 and 60 mm. In addition to this, the continuous casting installation shown in FIG. 2 combines two further devices which serve to influence the action of the counter screen 5 on the liquid head of the casting strand 4. The counter screen 5 is interrupted in the area of at least one system corner by a gap as a non-conductive section 7. A schematically drawn, electrically conductive contact element 8 is attached to the counter screen 5 on one side of the section 7 and bridges this section in a closed position in which the contact element 8 on the other side of the section 7 connects to the counter screen 5 in an electrically conductive manner. If no induced current is to flow in the counter screen 5 in the pouring phase, the contact element 8 is brought into a position which does not represent a bridging of the section 7.

Zur direkten Einspeisung eines zusätzlichen Wechselstroms in die Schleife des Gegenschirms 5 ist dieser beidseitig des Abschnitts 7 mit Stromanschlüssen versehen, welche an die Wechselstromquelle 10 geschlossen werden können. Das Kontaktelement 8 befindet sich hierbei nicht in Schliess­lage.For the direct feeding of an additional alternating current into the loop of the counter screen 5, this is provided on both sides of the section 7 with current connections which can be connected to the alternating current source 10. The contact element 8 is not in the closed position.

Die Figur 3 stellt eine alternative Ausführung der in Figur 1 gezeigten Stranggiessanlage dar. Dabei ist der Gegen­schirm 5 mit dem Schirm 2 starr über ein dielektrisches Zwischenstück 11 verbunden. Dieses ist mit Kühlmitteldurch­trittsöffnungen versehen, welche längs des Gussstrangum­fangs in geeignetem Abstand angeordnet sind.FIG. 3 shows an alternative embodiment of the continuous casting installation shown in FIG. 1. The counter screen 5 with the screen 2 is rigid via a dielectric Intermediate piece 11 connected. This is provided with coolant passage openings which are arranged at a suitable distance along the circumference of the cast strand.

In Figur 4 ist wiederum eine Stranggiessanlage mit vertikal verstellbarem Gegenschirm 5 dargestellt. Der Querschnitt verläuft durch einen Bereich in der Nähe einer Vertikal­kante des Gussstranges 4. Auf der oberen Kante des Gegen­schirms 5 ist eine dielektrische Kühlmittelflussschikane 13 aufgesetzt. Diese deckt nach dem Uebergang in die statio­näre Giessphase den Abstand 9 zwischen dem Schirm 2 und dem Gegenschirm 5 zu drei Vierteln zu und lenkt damit einen Grossteil der aus dem Kühlkasten 3 tretenden Kühlflüssig­keit ab.FIG. 4 again shows a continuous caster with a vertically adjustable counter screen 5. The cross section runs through an area in the vicinity of a vertical edge of the cast strand 4. A dielectric coolant flow baffle 13 is placed on the upper edge of the counter screen 5. After the transition to the stationary casting phase, this covers the distance 9 between the screen 2 and the counter screen 5 to three quarters and thus deflects a large part of the cooling liquid emerging from the cooling box 3.

Claims (20)

1. Vorrichtung zum berührungslosen, vertikal abwärts ge­richteten Stranggiessen von Metallen im elektromagneti­schen Wechselfeld, mit einem Induktor (1), einem Kühl­mittelkasten mit einer Vorrichtung zur Zuleitung eines Kühlmittels (3) auf die Oberfläche des Gussstranges (4) und einem elektrisch leitenden, nicht-ferromagneti­schen, nach unten sich verjüngenden Schirm (2) oberhalb der durch die tiefstliegenden Unterkanten des Induktors (1) definierten Ebene,
dadurch gekennzeichnet,
dass in Giessrichtung in einem Abstand (9) zum Schirm (2) ein elektrisch leitender, nicht-ferromagnetischer, nach oben sich verjüngender Gegenschirm (5) derart an­geordnet ist, dass der Abstand (9) mindestens 2 mm und höchstens die Höhe des Induktors (1) beträgt.1. Device for contactless, vertically downward casting of metals in an alternating electromagnetic field, with an inductor (1), a coolant box with a device for supplying a coolant (3) to the surface of the cast strand (4) and an electrically conductive, non- ferromagnetic shield (2) tapering downwards above the plane defined by the deepest lower edges of the inductor (1),
characterized,
that an electrically conductive, non-ferromagnetic counter-screen (5) tapering upwards is arranged at a distance (9) from the screen (2) in such a way that the distance (9) is at least 2 mm and at most the height of the inductor ( 1). 2. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, dass der Gegenschirm (5) zur Aufnahme eines Kühlmittels mit einem Hohlraum versehen ist.2. Device according to claim 1, characterized in that the counter screen (5) for receiving a coolant is provided with a cavity. 3. Vorrichtung nach Anspruch 2, dadurch gekennzeichnet, dass der Gegenschirm (5) gegen den Gussstrang (4) ge­richtete Kühlmitteldurchlässe (6) aufweist.3. Device according to claim 2, characterized in that the counter screen (5) against the cast strand (4) directed coolant passages (6). 4. Vorrichtung nach wenigstens einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, dass der Schirm (2) mit dem Gegenschirm (5) über mindestens ein dielektrisches Zwischenstück (11) starr verbunden ist.4. The device according to at least one of claims 1 to 3, characterized in that the screen (2) with the counter screen (5) via at least one dielectric intermediate piece (11) is rigidly connected. 5. Vorrichtung nach Anspruch 4, dadurch gekennzeichnet, dass das Zwischenstück (11) sich über den gesamten horizontalen Umfang des Gegenschirms (5) erstreckt und mit Kühlmitteldurchtrittsöffnungen (12) versehen ist.5. The device according to claim 4, characterized in that the intermediate piece (11) extends over the entire horizontal circumference of the counter screen (5) and is provided with coolant passage openings (12). 6. Vorrichtung nach wenigstens einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, dass der Gegenschirm zur Veränderung des Abstandes (9) vertikal verstellbar ist.6. The device according to at least one of claims 1 to 3, characterized in that the counter screen for changing the distance (9) is vertically adjustable. 7. Vorrichtung nach Anspruch 6, dadurch gekennzeichnet, dass der Gegenschirm (5) am Kühlmittelkasten (3) verti­kal verstellbar verankert ist.7. The device according to claim 6, characterized in that the counter screen (5) on the coolant box (3) is anchored vertically adjustable. 8. Vorrichtung nach Anspruch 6 oder 7, dadurch gekenn­zeichnet, dass dem Gegenschirm (5) an ausgewählten Stellen, entsprechend den Stellen des Gussstrangumfangs mit geringerem Kühlbedarf, dielektrische Kühlmittel­flussschikanen (13) aufgesetzt sind, welche den Gegen­schirm (5) vertikal um eine höchstens dem Abstand (9) entsprechende Höhe überragen.8. The device according to claim 6 or 7, characterized in that the counter screen (5) at selected locations, corresponding to the locations of the cast strand circumference with lower cooling requirements, dielectric coolant flow baffles (13) are placed, which the counter screen (5) vertically by a maximum of Surpass distance (9) by the appropriate height. 9. Vorrichtung nach wenigstens einem der Ansprüche 1 bis 8, dadurch gekennzeichnet, dass der Gegenschirm (5) um den Gussstrang (4) eine geschlossene Schleife bildet.9. The device according to at least one of claims 1 to 8, characterized in that the counter screen (5) around the cast strand (4) forms a closed loop. 10. Vorrichtung nach wenigstens einem der Ansprüche 1 bis 8, dadurch gekennzeichnet, dass der Gegenschirm (5) um den Gussstrang (4) eine Schleife bildet, welche durch elektrisch nichtleitende Abschnitte (7) unterbrochen ist und diese durch bewegliche, elektrisch leitende Kontaktelemente (8) in einer Schliesslage überbrückt sind.10. The device according to at least one of claims 1 to 8, characterized in that the counter screen (5) around the cast strand (4) forms a loop which is interrupted by electrically non-conductive sections (7) and this by movable, electrically conductive contact elements ( 8) are bridged in a closed position. 11. Vorrichtung nach wenigstens einem der Ansprüche 1 bis 8, dadurch gekennzeichnet, dass der Gegenschirm (5) um den Gussstrang (4) eine Schleife bildet, die an ei­ner Stelle unterbrochen ist und mit ihren offenen Enden an eine Wechselstromquelle (10) angeschlossen ist.11. The device according to at least one of claims 1 to 8, characterized in that the counter screen (5) forms a loop around the cast strand (4), which is interrupted at one point and is connected with its open ends to an AC power source (10) . 12. Vorrichtung nach wenigstens einem der Ansprüche 1 bis 8, dadurch gekennzeichnet, dass der Gegenschirm (5) um den Gussstrang (4) eine Schleife bildet, die an mehre­ren Stellen unterbrochen und dadurch in isolierte Ab­schnitte unterteilt ist, welche jeweils mit ihren Enden an Wechselstromquellen (10) angeschlossen sind.12. The device according to at least one of claims 1 to 8, characterized in that the counter screen (5) around the cast strand (4) forms a loop, which is interrupted at several points and thereby divided into isolated sections, each with their ends on AC power sources (10) are connected. 13. Verfahren zum berührungslosen, vertikal abwärts gerich­teten Stranggiessen von Metallen, bestehend aus einer Angiess- und einer stationären Phase, dadurch gekenn­zeichnet, dass durch Giessen in einer Vorrichtung nach wenigstens einem der Ansprüche 1 bis 12 die Schmelze­zirkulation im flüssigen Kopf des Gussstranges (4) zu­mindest in der stationären Giessphase verringert wird.13. A method for non-contact, vertically downward continuous casting of metals, consisting of a casting and a stationary phase, characterized in that by casting in a device according to at least one of claims 1 to 12, the melt circulation in the liquid head of the cast strand (4) is reduced at least in the stationary casting phase. 14. Verfahren nach Anspruch 13, dadurch gekennzeichnet, dass bei der Angiessphase der Abstand (9) mindestens die halbe und höchstens die ganze Höhe des Induktors (1) beträgt und nach dem Uebergang in die stationäre Phase der Abstand (9) auf zwischen 2 mm und der halben Höhe des Induktors (1) verringert wird.14. The method according to claim 13, characterized in that in the pouring phase, the distance (9) at least is half and at most the entire height of the inductor (1) and after the transition to the stationary phase the distance (9) is reduced to between 2 mm and half the height of the inductor (1). 15. Verfahren nach Anspruch 13, dadurch gekennzeichnet, dass in der Angiessphase die Kontaktelemente (8) in einer Position stehen, welche die nichtleitenden Ab­schnitte (7) nicht überbrücken, sodass der Gegenschirm (5) in der Angiessphase um den Gussstrang (4) keine elektrisch leitend geschlossene Schleife bildet.15. The method according to claim 13, characterized in that in the casting phase the contact elements (8) are in a position which does not bridge the non-conductive sections (7), so that the counter screen (5) in the casting phase around the cast strand (4) is none forms an electrically conductive closed loop. 16. Verfahren nach Anspruch 13, dadurch gekennzeichnet, dass zumindest in der stationären Phase die Schleife des Gegenschirms (5), gegebenenfalls die isolierten Ab­schnitte des Gegenschirms (5), von einer Wechselstrom­quelle (10) direkt gespiesen wird, welche dieselbe Fre­quenz wie das vom Induktor () ausgehende elektromagne­tische Wechselfeld aufweist und deren Stromamplitude geringer als diejenige des Induktors (1) ist.16. The method according to claim 13, characterized in that at least in the stationary phase, the loop of the counter screen (5), optionally the isolated sections of the counter screen (5), is fed directly from an AC power source (10) which has the same frequency as that of Inductor () has outgoing alternating electromagnetic field and whose current amplitude is less than that of the inductor (1). 17. Verfahren nach Anspruch 16, dadurch gekennzeichnet, dass in der stationären Phase zwischen dem von der Wechselstromquelle (10) in den Gegenschirm (5) einge­spiesenen Strom und dem im Induktor (1) fliessenden Strom eine Phasenverschiebung von 150 bis 180° einge­stellt wird.17. The method according to claim 16, characterized in that a phase shift of 150 to 180 ° is set in the stationary phase between the current fed by the alternating current source (10) into the counter screen (5) and the current flowing in the inductor (1). 18. Verfahren nach wenigstens einem der Ansprüche 13 bis 17, dadurch gekennzeichnet, dass der Gussstrang (4) zu­sätzlich zur Kühlung aus dem Kühlmittelkasten (3) mit einem aus den Kühlmitteldurchlässen (6) tretenden Kühl­mittel beaufschlagt wird.18. The method according to at least one of claims 13 to 17, characterized in that the cast strand (4) in addition to cooling from the coolant box (3) with a coolant emerging from the coolant passages (6) is applied. 19. Verfahren nach Anspruch 18, dadurch gekennzeichnet, dass beim Aufbringen des Kühlmittels aus dem Kühlmit­telkasten (3) auf die Oberfläche des Gussstrangs (4) ein Gas freigesetzt wird und daraus entstehende Iso­lierschichten durch das aus den Kühlmitteldurchlässen (6) tretende Kühlmittel aufgebrochen werden.19. The method according to claim 18, characterized in that when the coolant is applied from the coolant box (3) to the surface of the cast strand (4), a gas is released and insulating layers resulting therefrom are broken up by the coolant emerging from the coolant passages (6). 20. Anwendung des Verfahrens nach wenigstens einem der An­sprüche 13 bis 19 zum Stranggiessen von Aluminiumlegie­rungen mit einem Magnesiumgehalt von mindestens 2 Gew.-%.20. Application of the method according to at least one of claims 13 to 19 for the continuous casting of aluminum alloys with a magnesium content of at least 2 wt .-%.
EP86810520A 1985-11-25 1986-11-17 Device and process for continuous casting of metals Expired - Lifetime EP0229589B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT86810520T ATE49361T1 (en) 1985-11-25 1986-11-17 DEVICE AND METHOD FOR CONTINUOUS CASTING OF METALS.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH5007/85 1985-11-25
CH500785 1985-11-25

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EP0229589A1 true EP0229589A1 (en) 1987-07-22
EP0229589B1 EP0229589B1 (en) 1990-01-10

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US (1) US4699204A (en)
EP (1) EP0229589B1 (en)
JP (1) JPS62130746A (en)
AT (1) ATE49361T1 (en)
AU (1) AU589704B2 (en)
CA (1) CA1275779C (en)
DE (1) DE3668124D1 (en)
ES (1) ES2012356B3 (en)
NO (1) NO166624C (en)
ZA (1) ZA868762B (en)

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EP0592360A1 (en) * 1992-10-06 1994-04-13 Alusuisse-Lonza Services Ag Machine for vertical continuous casting in a magnetic field

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JPH0270361A (en) * 1988-09-02 1990-03-09 Nippon Steel Corp Apparatus and method for continuously casting molten metal
US6491087B1 (en) 2000-05-15 2002-12-10 Ravindra V. Tilak Direct chill casting mold system

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US4158379A (en) * 1978-07-03 1979-06-19 Olin Corporation Electromagnetic casting method and apparatus
US4215738A (en) * 1979-03-30 1980-08-05 Olin Corporation Anti-parallel inductors for shape control in electromagnetic casting
EP0015870A1 (en) * 1979-03-07 1980-09-17 Schweizerische Aluminium AG Electro-magnetic mould for continuous casting
EP0022649A2 (en) * 1979-07-11 1981-01-21 Olin Corporation Process and apparatus for the electromagnetic casting of metals and non-magnetic screen for use therein
EP0109357A1 (en) * 1982-11-12 1984-05-23 Schweizerische Aluminium Ag Electromagnetic continuous casting mould

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US4508160A (en) * 1981-11-20 1985-04-02 Swiss Aluminium Ltd. Process for cooling in ingot during continuous casting
US4544016A (en) * 1983-04-21 1985-10-01 Yetselev Zinovy N Continuous casting process and apparatus
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US4158379A (en) * 1978-07-03 1979-06-19 Olin Corporation Electromagnetic casting method and apparatus
EP0015870A1 (en) * 1979-03-07 1980-09-17 Schweizerische Aluminium AG Electro-magnetic mould for continuous casting
US4215738A (en) * 1979-03-30 1980-08-05 Olin Corporation Anti-parallel inductors for shape control in electromagnetic casting
EP0022649A2 (en) * 1979-07-11 1981-01-21 Olin Corporation Process and apparatus for the electromagnetic casting of metals and non-magnetic screen for use therein
EP0109357A1 (en) * 1982-11-12 1984-05-23 Schweizerische Aluminium Ag Electromagnetic continuous casting mould

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0592360A1 (en) * 1992-10-06 1994-04-13 Alusuisse-Lonza Services Ag Machine for vertical continuous casting in a magnetic field
CH688129A5 (en) * 1992-10-06 1997-05-30 Alusuisse Lonza Services Ag Casting machine for the vertical continuous casting in a magnetic field.

Also Published As

Publication number Publication date
AU6491886A (en) 1987-05-28
ES2012356B3 (en) 1990-03-16
NO166624B (en) 1991-05-13
EP0229589B1 (en) 1990-01-10
ATE49361T1 (en) 1990-01-15
AU589704B2 (en) 1989-10-19
JPS62130746A (en) 1987-06-13
ZA868762B (en) 1987-09-30
US4699204A (en) 1987-10-13
CA1275779C (en) 1990-11-06
NO864633D0 (en) 1986-11-20
NO166624C (en) 1991-08-21
DE3668124D1 (en) 1990-02-15

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