EP0166718B1 - Method of and installation for continuous casting of metallic melts - Google Patents

Method of and installation for continuous casting of metallic melts Download PDF

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Publication number
EP0166718B1
EP0166718B1 EP19850890141 EP85890141A EP0166718B1 EP 0166718 B1 EP0166718 B1 EP 0166718B1 EP 19850890141 EP19850890141 EP 19850890141 EP 85890141 A EP85890141 A EP 85890141A EP 0166718 B1 EP0166718 B1 EP 0166718B1
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EP
European Patent Office
Prior art keywords
melt
feed line
cross
chill
melt feed
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Expired
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EP19850890141
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German (de)
French (fr)
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EP0166718A2 (en
EP0166718A3 (en
Inventor
Peter Dipl.-Ing. Machner
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Boehler GmbH
Primetals Technologies Austria GmbH
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Boehler GmbH
Voest Alpine Industrienlagenbau GmbH
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Publication of EP0166718A2 publication Critical patent/EP0166718A2/en
Publication of EP0166718A3 publication Critical patent/EP0166718A3/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
    • B22D11/04—Continuous casting of metals, i.e. casting in indefinite lengths into open-ended moulds
    • B22D11/045—Continuous casting of metals, i.e. casting in indefinite lengths into open-ended moulds for horizontal casting
    • B22D11/047—Means for joining tundish to mould
    • 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

Definitions

  • the invention relates to a method and an apparatus for the continuous casting of metallic melts, in particular of higher melting alloys, e.g. B. steel according to the preamble of claims 1 and 7.
  • melts can be caused to rotate, for example, by electromagnetic stirring devices around the casting direction or around the longitudinal direction of the mold, or it can cause flows from the outer edge of the mold to the inner edge of the mold.
  • Such flows can be achieved by suitably arranged electromagnetic stirring devices and corresponding controls.
  • a process for vertical continuous casting is known from DE-OS-2 903 234, the melt reaching the mold from a melt container via a pouring tube.
  • An electromagnetic stirring device is arranged around the pouring tube, by means of which the molten metal can be stirred, so that it already provides a movement which is superimposed on the direction of flow and enters the mold.
  • the present invention has set itself the goal of a method and an apparatus for the horizontal continuous casting of metallic melts, in particular of higher melting alloys, e.g. As steel, to create, in which or which a particularly high surface quality is achieved, which has the lowest possible equipment, and allows energy-saving operation, and the inner quality of the strand significantly increased.
  • higher melting alloys e.g. As steel
  • the process according to the invention for the continuous casting of metallic melts in particular of higher melting alloys, e.g. B. steel, the metallic melt via at least one melt feed line, e.g. B. channel, from a melt container, pan, or the like.
  • a melt feed line e.g. B. channel
  • a substantially horizontally arranged and connected to this liquid-tight, preferably liquid-cooled mold via a smaller cross-sectional area than the mold having an outlet opening of a nozzle stone is fed, and the partially solidified strand from the Chill mold, preferably gradually, optionally pulled backwards with a partial step, consists essentially in that the melt is introduced into a substantially horizontal part of the melt feed line, essentially tangentially, so that the melt is caused to rotate about its longitudinal axis, after which the rotating melt is introduced into the mold.
  • the melt already rotates into the mold, so that the boundary layers, i.e. Surface layers, which e.g. B.
  • melt feed line has at least two differently shaped and / or large cross sections in the mouth region, the corresponding sections of the melt feed line opening tangentially into one another, then a stirring movement in the melt can be achieved without further energy expenditure and expensive devices.
  • the melt feed line has at least two different, adjacent cross-sectional areas, the melt being introduced approximately tangentially, preferably from that section with the smaller cross-sectional area into the one with the larger cross-sectional area, then rotation of the melt around the essentially horizontal longitudinal axis of the Melt feed in front of the mold without additional energy, e.g. B. by electromagnets or the like., At the same time the entire metal current is set in motion.
  • a particularly homogeneous strand can be obtained if the flow rate of the melt at each point of the melt feed is on average over time, is kept constant.
  • a particularly low overheating of the melt in the melt container can be maintained if the melt is discharged from an essentially vertically arranged melt feed line from the melt container into an inclined, preferably essentially horizontally arranged, short melt feed line.
  • a short melt feed line can also be achieved in that the melt flows faster in the substantially vertically arranged melt feed line than in the melt feed line inclined to it and is introduced therein essentially tangentially to the cross section thereof.
  • a device for the continuous casting of metallic melts, in particular higher melting metals and alloys, e.g. B. steel, with melt container, essentially horizontally arranged, preferably liquid-cooled mold and at least one, arranged between them melt feed line, a smaller cross-sectional area than the mold (4) having nozzle block (3) and a strand extraction device, consists essentially in that the melt feed line has at least two adjoining sections of different shapes, the first section opening in the direction of flow of the melt essentially tangentially opening into the one which is arranged essentially horizontally in front of the mold and, if appropriate, the sections in the opening area are shaped differently and / or have different cross-sectional areas.
  • the axes of the melt feed in the area of the diversion are skewed and preferably have a normal distance of 1/2 to 1/6 of the inner diameter of the essentially horizontal part of the melt feed from one another.
  • the melt feed line in the melt container can be closed with a stopper.
  • FIG. 1 shows the schematic representation of a horizontal continuous casting installation in section and FIG. 2 shows the section through a melt feed line.
  • melt feed line 1 has a melt feed line 2, which opens into the liquid-cooled mold 4 via an outlet opening of the nozzle block 3.
  • the smallest free cross-sectional area of the nozzle stone is smaller than that of the mold.
  • the melt feed line protruding from the melt container is fastened to the melt container 1 by means of a clamp 5.
  • the melt supply to the mold can be prevented by lowering the stopper 6.
  • the melt feed line has different cross sections, the section 7 lying first in the direction of flow opening tangentially into the following section 8. In the mouth area, the cross section 7 is essentially slit-shaped.
  • section 9 shows a further section through a melt feed line, the section 9 with axis 11 of the melt feed line, which has an essentially circular cross section, opening tangentially into section 10 with axis 12 of the melt feed line, which likewise has a circular cross section.
  • the cross-sectional area of section 9 is approximately 15 cm 2 , whereas that of section 10 is 43 cm 2 .
  • the normal distance a is approx. 1/4 of the inner diameter d of the melt feed line with the larger cross-sectional area.
  • iron-based alloys and carbon steels with different compositions were initially cast using the horizontal continuous casting process.
  • the casting cross sections were 0 96 mm and qu. 100 mm.
  • the melt weights were 2.5 and 14 t.
  • the strand material was subjected to extensive quality testing. For this, the examination was carried out in the transverse and longitudinal directions of the strand.
  • the casting speed or average strand withdrawal speed from the mold was 1.4 m / min.
  • the mold had a cross section of 96 mm round.
  • the steel overheated at the beginning of the casting was 75 ° C, accordingly the steel temperature in the melt container was 1570 ° C.
  • the melt feed line had a first section with an inner diameter of 40 mm, which ended tangentially in the second section with an inner diameter of 75 mm.
  • the two cross sections were circular.
  • the normal distance between the axially skewed axes was 17.5 mm.
  • the examination in the transverse and longitudinal directions of the strand gave the following results:
  • the cross-sectional shape of the strands was circular, the strand shell formation in the mold was even.
  • the rotation of the melt had the effect that no cooling stress cracks occurred in the strand zone near the surface even with the high steel overheating.
  • the crystallization form was largely globulitic, the eccentricity of the blow hole could be significantly reduced.
  • the casting speed was 1.6 m / min.
  • the casting cross section was qu. 100 mm.
  • the overheating of the alloy at the beginning of the casting was 80 ° C.
  • the steel temperature in the melt container was accordingly 1540 ° C.
  • the cross-sectional shape of the strands was square, the rotation of the melt having the effect that no cooling stress cracks occurred in the strand even with high steel overheating.
  • the crystallization form was largely globulitic.
  • the eccentricity of the blow hole could be reduced considerably, while at the same time a significant reduction in the notches on the strand surface could be achieved. Subsequent hot deformations showed no cracks after the first deformation stitch.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)

Description

Die Erfindung bezieht sich auf ein Verfahren und eine Vorrichtung zum Stranggießen von metallischen Schmelzen, insbesondere von höher schmelzenden Legierungen, z. B. Stahl gemäß Oberbegriff der Ansprüche 1 und 7.The invention relates to a method and an apparatus for the continuous casting of metallic melts, in particular of higher melting alloys, e.g. B. steel according to the preamble of claims 1 and 7.

Beim Erstarren von metallischen Schmelzen, insbesondere von Legierungen, kommt es zu sogenannten Seigerungen, d.h. unterschiedlichen chemischen bzw. physikalischen Zusammensetzungen bezogen auf den Quer- und gegebenenfalls Längsschnitt des erstarrenden Blockes bzw. Stranges. Um derartige Seigerungen zu verhindern bzw. geringer zu halten, ist es sowohl beim Block- als auch Strangguß bekannt, die Schmelze während des Erstarrens in der Kokille in Bewegung zu halten. Hiebei kann die Schmelze beispielsweise durch elektromagnetische Rühreinrichtungen in Rotation um die Gießrichtung oder um die Kokillenlängsachsrichtung gebracht werden oder es können Strömungen von dem Kokillenaußenrand zu dem Kokilleninnenrand verursacht werden. Derartige Strömungen können durch geeignet angeordnete elektromagnetische Rührvorrichtungen und entsprechende Steuerungen erreicht werden.When metal melts, especially alloys, solidify, so-called segregations occur, i.e. different chemical or physical compositions based on the cross-section and, where appropriate, longitudinal section of the solidifying block or strand. In order to prevent such segregations or to keep them lower, it is known both in block and continuous casting to keep the melt in motion in the mold during solidification. Here, the melt can be caused to rotate, for example, by electromagnetic stirring devices around the casting direction or around the longitudinal direction of the mold, or it can cause flows from the outer edge of the mold to the inner edge of the mold. Such flows can be achieved by suitably arranged electromagnetic stirring devices and corresponding controls.

Einsetzende Schmelzenströmungen vor der Kristallisationsfront können jedoch auch zu Inhomogenitäten bzw. Seigerstreifen führen. Diese bekannten negativen Seigerungen (white bands) beeinträchtigen in hohem Maße die Qualität des Produktes.Melt flows beginning in front of the crystallization front can also lead to inhomogeneities or Seiger stripes. These known negative segregations (white bands) greatly affect the quality of the product.

Aus der DE-OS-2 903 234 wird ein Verfahren zum vertikalen Stranggießen bekannt, wobei die Schmelze von einem Schmelzenbehälter über ein Gießrohr in die Kokille gelangt. Um das Gießrohr ist eine elektromagnetische Rührvorrichtung angeordnet, mit welcher die Metallschmelze gerührt werden kann, sodaß dieselbe bereits mit einer zusätzlich zur Strömungsrichtung überlagerten Bewegung versehen, in die Kokille eintritt.A process for vertical continuous casting is known from DE-OS-2 903 234, the melt reaching the mold from a melt container via a pouring tube. An electromagnetic stirring device is arranged around the pouring tube, by means of which the molten metal can be stirred, so that it already provides a movement which is superimposed on the direction of flow and enters the mold.

Aus DE-G-8 201 246.6, auf welcher die Oberbegriffe der Ansprüche 1 und 7 basieren, wird eine Anlage zum horizontalen Stranggießen von Metall, insbesondere von Stahl bekannt, wobei ein eine Gießmündung aufweisender Verteilerbehälter zur Aufnahme des zu vergießenden Flüssigmetalls mit einer annähernd horizontal ausgerichteten wassergekühlten Kokille verbunden ist.From DE-G-8 201 246.6, on which the preambles of claims 1 and 7 are based, a system for the horizontal continuous casting of metal, in particular steel, is known, wherein a pouring container having a pouring mouth for receiving the liquid metal to be cast with an approximately horizontal aligned water-cooled mold is connected.

Beim horizontalen Strangguß ist es bereits bekannt geworden, vor der Kokille in der Schmelzenzuleitung ein elektromagnetisches Ventil vorzusehen, um den Schmelzenzufluß zu verhindern.In the case of horizontal continuous casting, it has already become known to provide an electromagnetic valve in front of the mold in the melt feed line in order to prevent the melt flow.

Die vorliegende Erfindung hat sich zum Ziel gesetzt, ein Verfahren und eine Vorrichtung zum horizontalen Stranggießen von metallischen Schmelzen, insbesondere von höher schmelzenden Legierungen, z. B. Stahl, zu schaffen, bei welchem bzw. welcher eine besonders hohe Oberflächengüte erreicht wird, das einen möglichst geringen apparativen Aufwand aufweist, und einen energiesparenden Betrieb erlaubt, sowie die Innengüte des Stranges wesentlich erhöht.The present invention has set itself the goal of a method and an apparatus for the horizontal continuous casting of metallic melts, in particular of higher melting alloys, e.g. As steel, to create, in which or which a particularly high surface quality is achieved, which has the lowest possible equipment, and allows energy-saving operation, and the inner quality of the strand significantly increased.

Das erfindungsgemäße Verfahren zum Stranggießen von metallischen Schmelzen, insbesondere von höher schmelzenden Legierungen, z. B. Stahl, wobei die metallische Schmelze über zumindest eine Schmelzenzuleitung, z. B. Kanal, von einem Schmelzenbehälter, Pfanne, od. dgl. einer im wesentlichen horizontal angeordneten und mit diesem flüssigkeitsdicht verbundenen, vorzugsweise flüssigkeitsgekühlten Kokille über eine, eine geringere Querschnittsfläche als die Kokille aufweisende Austrittsöffnung eines Düsensteines zugeleitet wird, und der teilerstarrte Strang aus der Kokille, vorzugsweise schrittweise, gegebenenfalls mit einem Teilschritt nach hinten gezogen wird, besteht im wesentlichen darin, daß die Schmelze in einen, im wesentlichen horizontalen Teil der Schmelzenzuleitung, im wesentlichen tangential eingeleitet wird, sodaß eine Rotation der Schmelze um dessen Längsachse bewirkt wird wonach die rotierende Schmelze in die Kokille eingeleitet wird. Bei einem derartigen Verfahren tritt die Schmelze bereits rotierend in die Kokille ein, sodaß auch die Grenzschichten, d.h. Oberflächenschichten, welche z. B. bei einem schrittweisen Abzug des Stranges Kerben aufweisen können, eine besonders hohe Homogenität besitzen, wobei gleichzeitig über die Querschnittsveränderung eine zusätzliche Verwirbelung in der Metallschmelzenströmungsrichtung aufgebracht wird. Ein weiterer Vorteil besteht darin, daß bereits beim Beginn der Strangschalenbildung eine Rotationsströmung der Metallschmelze gegeben ist.The process according to the invention for the continuous casting of metallic melts, in particular of higher melting alloys, e.g. B. steel, the metallic melt via at least one melt feed line, e.g. B. channel, from a melt container, pan, or the like. A substantially horizontally arranged and connected to this liquid-tight, preferably liquid-cooled mold via a smaller cross-sectional area than the mold having an outlet opening of a nozzle stone is fed, and the partially solidified strand from the Chill mold, preferably gradually, optionally pulled backwards with a partial step, consists essentially in that the melt is introduced into a substantially horizontal part of the melt feed line, essentially tangentially, so that the melt is caused to rotate about its longitudinal axis, after which the rotating melt is introduced into the mold. In such a process, the melt already rotates into the mold, so that the boundary layers, i.e. Surface layers, which e.g. B. can have notches with a gradual withdrawal of the strand, have a particularly high homogeneity, with an additional swirl in the molten metal flow direction being applied simultaneously via the change in cross section. Another advantage is that there is a rotational flow of the molten metal already at the start of the strand shell formation.

Weist die Schmelzenzuleitung zumindest zwei im Mündungsbereich unterschiedlich geformte und/oder große Querschnitte auf, wobei die entsprechenden Abschnitte der Schmelzenzuleitung ineinander tangential münden, so kann eine Rührbewegung in der Schmelze ohne weiteren Energieaufwand und aufwendige Vorrichtungen erreicht werden.If the melt feed line has at least two differently shaped and / or large cross sections in the mouth region, the corresponding sections of the melt feed line opening tangentially into one another, then a stirring movement in the melt can be achieved without further energy expenditure and expensive devices.

Weist die Schmelzenzuleitung zumindest zwei unterschiedliche, aneinander anschließende Querschnittsflächen auf, wobei die Schmelze, vorzugsweise von jenem Abschnitt mit der kleineren Querschnittsfläche in den mit der größeren Querschnittsfläche, etwa tangential eingeleitet wird, so kann ebenfalls eine Rotation der Schmelze um die im wesentlichen horizontale Längsachse der Schmelzenzuleitung vor der Kokille ohne zusätzliche Energie, z. B. durch Elektromagnete od. dgl., erreicht werden, wobei gleichzeitig der gesamte Metallstrom in Bewegung versetzt wird.If the melt feed line has at least two different, adjacent cross-sectional areas, the melt being introduced approximately tangentially, preferably from that section with the smaller cross-sectional area into the one with the larger cross-sectional area, then rotation of the melt around the essentially horizontal longitudinal axis of the Melt feed in front of the mold without additional energy, e.g. B. by electromagnets or the like., At the same time the entire metal current is set in motion.

Ein besonders homogener Strang kann dann erhalten werden, wenn die Strömungsgeschwindigkeit der Schmelze an jedem Punkt der Schmelzenzuleitung im Mittel über die Zeit, konstant gehalten wird.A particularly homogeneous strand can be obtained if the flow rate of the melt at each point of the melt feed is on average over time, is kept constant.

Eine besonders geringe Überhitzung der Schmelze im Schmelzenbehälter kann dann eingehalten werden, wenn die Schmelze von einer im wesentlichen vertikal angeordneten Schmelzenzuleitung vom Schmelzenbehälter in eine hiezu geneigt, vorzugsweise im wesentlichen horizontal angeordnete kurze Schmelzenzuleitung abgeleitet wird.A particularly low overheating of the melt in the melt container can be maintained if the melt is discharged from an essentially vertically arranged melt feed line from the melt container into an inclined, preferably essentially horizontally arranged, short melt feed line.

Eine kurze Schmelzenzuleitung kann auch dadurch erreicht werden, daß die Schmelze in der, im wesentlichen vertikal angeordneten Schmelzenzuleitung schneller strömt, als in der zu dieser geneigt angeordneten Schmelzenzuleitung und in dieser im wesentlichen tangential zum Querschnitt derselben eingeleitet wird.A short melt feed line can also be achieved in that the melt flows faster in the substantially vertically arranged melt feed line than in the melt feed line inclined to it and is introduced therein essentially tangentially to the cross section thereof.

Eine Vorrichtung zum Stranggießen von metallischen Schmelzen, insbesondere höher schmelzenden Metallen und Legierungen, z. B. Stahl, mit Schmelzenbehälter, im wesentlichen horizontal angeordneter, vorzugsweise flüssigkeitsgekühlter Kokille und zumindest einer, zwischen diesen angeordneten Schmelzenzuleitung, einem, eine geringere Querschnittsfläche als die Kokille (4) aufweisenden Düsenstein (3) und einer Strangabzugseinrichtung, besteht im wesentlichen darin, daß die Schmelzenzuleitung zumindest zwei aneinander anschließende Abschnitte unterschiedlicher Form aufweist, wobei in Fließrichtung der Schmelze gesehen, der erste Abschnitt in denjenigen, der im wesentlichen horizontal vor der Kokille angeordnet ist, im wesentlichen tangential mündet und gegebenenfalls die Abschnitte im Mündungsbereich unterschiedlich geformt sind und/oder unterschiedliche Querschnittsflächen aufweisen.A device for the continuous casting of metallic melts, in particular higher melting metals and alloys, e.g. B. steel, with melt container, essentially horizontally arranged, preferably liquid-cooled mold and at least one, arranged between them melt feed line, a smaller cross-sectional area than the mold (4) having nozzle block (3) and a strand extraction device, consists essentially in that the melt feed line has at least two adjoining sections of different shapes, the first section opening in the direction of flow of the melt essentially tangentially opening into the one which is arranged essentially horizontally in front of the mold and, if appropriate, the sections in the opening area are shaped differently and / or have different cross-sectional areas.

Mit einer derartigen Vorrichtung ist eine besonders einfache Vorrichtung zum horizontalen Stranggießen geschaffen, wobei gleichzeitig eine Rotation der in die Kokille eintretenden Schmelze erreicht wird, sodaß Oberflächenschäden des Stranges und auch Seigerungen besonders gering gehalten werden können.With a device of this type, a particularly simple device for horizontal continuous casting is created, wherein at the same time rotation of the melt entering the mold is achieved, so that surface damage to the strand and also segregation can be kept particularly low.

Gemäß einem weiteren Merkmal der Erfindung sind die Achsen der Schmelzenzuleitung im Bereich der Umleitung windschief und weisen vorzugsweise einen Normalabstand von 1/2 bis 1/6 des Innendurchmessers des im wesentlichen horizontalen Teiles der Schmelzenzuleitung voneinander auf. Gemäß einer weiteren vorteilhaften Ausbildung der vorliegenden Erfindung ist die Schmelzenzuleitung im Schmelzenbehälter mit einem Stopfen verschließbar.According to a further feature of the invention, the axes of the melt feed in the area of the diversion are skewed and preferably have a normal distance of 1/2 to 1/6 of the inner diameter of the essentially horizontal part of the melt feed from one another. According to a further advantageous embodiment of the present invention, the melt feed line in the melt container can be closed with a stopper.

Im folgenden wird die Erfindung anhand der Zeichnungen und Beispiele näher erläutert.The invention is explained in more detail below with reference to the drawings and examples.

Es zeigen Fig. 1 die schematische Darstellung einer Horizontalstranggußanlage im Schnitt und Fig. 2 den Schnitt durch eine Schmelzenzuleitung.1 shows the schematic representation of a horizontal continuous casting installation in section and FIG. 2 shows the section through a melt feed line.

Der Schmelzenbehälter 1 gemäß Fig. 1 weist eine Schmelzenzuleitung 2 auf, die über eine Austrittsöffnung des Düsensteines 3 in die flüssigkeitsgekühlte Kokille 4 mündet. Die kleinste freie Querschnittsfläche des Düsensteines ist geringer als jene der Kokille. Die aus dem Schmelzenbehälter herausragende Schmelzenzuleitung ist über eine Schelle 5 am Schmelzenbehälter 1 befestigt. Die Schmelzenzufuhr zur Kokille kann durch Senken des Stopfens 6 unterbunden werden. Wie aus Fig. 1a ersichtlich, weist die Schmelzenzuleitung unterschiedliche Querschnitte auf, wobei der in Strömungsrichtung zuerst liegende Abschnitt 7 in den darauffolgenden Abschnitt 8 tangential mündet. Im Mündungsbereich ist der Querschnitt 7 im wesentlichen schlitzförmig.1 has a melt feed line 2, which opens into the liquid-cooled mold 4 via an outlet opening of the nozzle block 3. The smallest free cross-sectional area of the nozzle stone is smaller than that of the mold. The melt feed line protruding from the melt container is fastened to the melt container 1 by means of a clamp 5. The melt supply to the mold can be prevented by lowering the stopper 6. As can be seen from FIG. 1 a, the melt feed line has different cross sections, the section 7 lying first in the direction of flow opening tangentially into the following section 8. In the mouth area, the cross section 7 is essentially slit-shaped.

In Fig. 2 ist ein weiterer Schnitt durch eine Schmelzenzuleitung dargestellt, wobei der Abschnitt 9 mit Achse 11 der Schmelzenzuleitung, welcher einen im wesentlichen kreisförmigen Querschnitt aufweist, tangential in den Abschnitt 10 mit Achse 12 der Schmelzenzuleitung mündet, welcher ebenfalls einen kreisförmigen Querschnitt aufweist. Die Querschnittsfläche des Abschnittes 9 beträgt ca. 15 cm2, wohingegen jene des Abschnittes 10 43 cm2 beträgt. Der Normalabstand a beträgt ca. 1/4 des Innendurchmessers d der Schmelzenzuleitung mit der größeren Querschnittsfläche.2 shows a further section through a melt feed line, the section 9 with axis 11 of the melt feed line, which has an essentially circular cross section, opening tangentially into section 10 with axis 12 of the melt feed line, which likewise has a circular cross section. The cross-sectional area of section 9 is approximately 15 cm 2 , whereas that of section 10 is 43 cm 2 . The normal distance a is approx. 1/4 of the inner diameter d of the melt feed line with the larger cross-sectional area.

Für eine Horizontalstranggußanlage ist es weiters erforderlich, daß ein Strangabzug vorgesehen wird, wobei dieser nicht Bestandteil der vorliegenden Erfindung ist, sodaß auf dessen Beschreibung hier verzichtet werden kann.For a horizontal continuous casting installation, it is also necessary to provide a continuous take-off, which is not part of the present invention, so that the description thereof can be dispensed with here.

In einer Pilot-Anlage wurden vorerst nach dem Stand der Technik unterschiedlich zusammengesetzte Eisenbasislegierungen und C-Stähle nach dem horizontalen Stranggußverfahren gegossen. Die Gießquerschnitte waren 0 96 mm und qu. 100 mm. Die Schmelzengewichte betrugen 2,5 und 14 t. Das Strangmaterial wurde einer eingehenden Qualitätserprobung unterworfen. Hierfür erfolgte die Untersuchung in Quer- und in Längsrichtung des Stranges.In a pilot plant, iron-based alloys and carbon steels with different compositions were initially cast using the horizontal continuous casting process. The casting cross sections were 0 96 mm and qu. 100 mm. The melt weights were 2.5 and 14 t. The strand material was subjected to extensive quality testing. For this, the examination was carried out in the transverse and longitudinal directions of the strand.

Die Erprobung der nach dem Stand der Technik gegossenen Stränge erbrachten folgende Resultate:

  • Rundstränge wiesen ein unterschiedliches Schalenwachstum auf, welches letztlich zu einer polygonalen Querschnittsform führte. Weiters waren Kühlspannungsrisse festgestellt worden, wobei sich die Strangfehler mit größer werdender Überhitzung des Stahles häuften. Der Lunker und die Erstarrungsstruktur waren im Strang exzentrisch angeordnet.
The testing of the strands cast according to the prior art yielded the following results:
  • Circular strands showed different shell growth, which ultimately led to a polygonal cross-sectional shape. In addition, cooling voltage cracks were found, with the strand defects increasing with increasing overheating of the steel. The blowhole and the solidification structure were arranged eccentrically in the strand.

Durch den Einsatz eines elektromagnetischen Feldes gelang es zwar, im Inneren des Stranges ab ca. 1/2 Radius die Kristallisationsform zu vergleichmäßigen und den exzentrischen Lunker in eine Kernporosität umzuwandeln, es entstanden jedoch konzentrisch angeordnete Streifen, negativer Seigerung, die sogenannten "white bands".By using an electromagnetic field, it was possible to even out the crystallization form inside the strand from approx. 1/2 radius and to convert the eccentric blow hole into a core porosity, but concentrically arranged stripes, negative segregation, the so-called "white bands".

Nach Einbau der erfindungsgemäßen Vorrichtung gemäß Fig. 1 und der Möglichkeit das erfindungsgemäße Verfahren anzuwenden, wurden die Versuche mit den gleichen Legierungen wiederholt. Die Erprobung der nach dem erfindungsgemäßen Verfahren gegossenen Stränge erbrachte folgende Ergebnisse:After installation of the device according to the invention according to FIG. 1 and the possibility of using the method according to the invention, the tests were repeated with the same alloys. Testing the strands cast by the process according to the invention gave the following results:

Beispiel 1:Example 1:

Guß von 2,5 t einer Legierung mit folgender Zusammensetzung in Gew.-%:

  • C 0,38, Si 0,25, Mn 0,7, P 0,021, S 0,012, Rest Eisen und Verunreinigungen.
Cast 2.5 t of an alloy with the following composition in% by weight:
  • C 0.38, Si 0.25, Mn 0.7, P 0.021, S 0.012, balance iron and impurities.

Die Gießgeschwindigkeit bzw. mittlere Strangabzugsgeschwindigkeit aus der Kokille betrug 1,4 m/min. Die Kokille hatte einen Querschnitt von 96 mm rund. Die Überhitzung des Stahles am Beginn des Gusses war 75°C, dementsprechend betrug die Stahltemperatur im Schmelzenbehälter 1570°C. Die Schmelzenzuleitung wies einen ersten Abschnitt mit einem Innendurchmesser von 40 mm auf der in den zweiten Abschnitt mit einem Innendurchmesser von 75 mm tangential mündete. Die beiden Querschnitte waren kreisförmig. Der Normalabstand der zueinander windschief angeordneten Achsen betrug 17,5 mm. Die Untersuchung in Quer- und Längsrichtung des Stranges ergab folgende Ergebnisse:The casting speed or average strand withdrawal speed from the mold was 1.4 m / min. The mold had a cross section of 96 mm round. The steel overheated at the beginning of the casting was 75 ° C, accordingly the steel temperature in the melt container was 1570 ° C. The melt feed line had a first section with an inner diameter of 40 mm, which ended tangentially in the second section with an inner diameter of 75 mm. The two cross sections were circular. The normal distance between the axially skewed axes was 17.5 mm. The examination in the transverse and longitudinal directions of the strand gave the following results:

Die Querschnittsform der Stränge war kreisrund, die Strangschalenbildung schon in der Kokille war gleichmäßig. Die Rotation der Schmelze bewirkte, daß auch bei der hohen Stahlüberhitzung keine Kühlspannungsrisse in der oberflächennahen Strangzone auftraten. Die Kristallisationsform war weitgehend globulitisch, die Exzentrizität des Lunkers konnte wesentlich gemindert werden.The cross-sectional shape of the strands was circular, the strand shell formation in the mold was even. The rotation of the melt had the effect that no cooling stress cracks occurred in the strand zone near the surface even with the high steel overheating. The crystallization form was largely globulitic, the eccentricity of the blow hole could be significantly reduced.

Beispiel 2:Example 2:

In einem weiteren Versuch, welcher mit der gleichen Stahlmarke wie im Beispiel 1 durchgeführt wurde, kamen nach der Kokille elektromagnetische Rührfelder zum Einsatz. Die Untersuchungen dieser Stränge erbrachten, daß eine wesentlich gesteigerte Güte der Stränge vorlag. Entgegen den Erwartungen und bisherigen Erfahrungen waren beim Einsatz des elektromagnetischen Wanderfeldes nach der Kokille keine Seigerstreifen im Strangmaterial aufgetreten. Das elektromagnetische Feld bewirkte eine weitere entscheidende Verbesserung der Stranginnenqualität.In a further experiment, which was carried out with the same steel brand as in Example 1, electromagnetic stirring fields were used after the mold. The examinations of these strands showed that the quality of the strands was significantly increased. Contrary to expectations and previous experience, no Seiger stripes appeared in the strand material when using the electromagnetic traveling field after the mold. The electromagnetic field brought about a further decisive improvement in the internal strand quality.

Als hervorragendes Merkmal der nach dem erfindungsgemäßen Verfahren gegossenen Stränge war die entscheidende Verbesserung der Kristallisation der oberflächennahen Strangzone und die Oberflächengüte. Bei gleichen Abzugsparametern waren die Kerben derart reduziert, daß bei der nachfolgenden Walzung keine Brüchigkeit, selbst bei hohen Verformungsgraden des Stranges im ersten Stich, auftrat.An outstanding feature of the strands cast by the process according to the invention was the decisive improvement in the crystallization of the strand zone near the surface and the surface quality. With the same withdrawal parameters, the notches were reduced in such a way that no fragility occurred in the subsequent rolling, even with high degrees of deformation of the strand in the first pass.

Beispiel 3:Example 3:

Es wurde eine Legierung folgender Zusammensetzung in Gew.-%:

  • C 0,03, Si 0,65, Mn 1,12, Cr 17,90, Ni 9,02, P 0,022 und S 0,012 Rest Eisen gegossen.
An alloy with the following composition in% by weight was:
  • C 0.03, Si 0.65, Mn 1.12, Cr 17.90, Ni 9.02, P 0.022 and S 0.012 balance cast iron.

Die Gießgeschwindigkeit betrug 1,6 m/min. Der Gießquerschnitt betrug qu. 100 mm. Die Überhitzung der Legierung am Beginn des Gusses betrug 80°C. Die Stahltemperatur im Schmelzenbehälter war demgemäß 1540° C.The casting speed was 1.6 m / min. The casting cross section was qu. 100 mm. The overheating of the alloy at the beginning of the casting was 80 ° C. The steel temperature in the melt container was accordingly 1540 ° C.

Die Querschnittsform der Stränge war quadratisch, wobei die Rotation der Schmelze bewirkte, daß auch bei der hohen Stahlüberhitzung keine Kühlspannungsrisse im Strang auftraten. Die Kristallisationsform war weitgehends globulitisch. Die Exzentrizität des Lunkers konnte wesentlich gemindert werden, wobei gleichzeitig eine wesentliche Verringerung der Kerben an der Strangoberfläche erreicht werden konnte. Bei anschließenden Warmverformungen traten nach dem ersten Verformungsstich keine Risse auf.The cross-sectional shape of the strands was square, the rotation of the melt having the effect that no cooling stress cracks occurred in the strand even with high steel overheating. The crystallization form was largely globulitic. The eccentricity of the blow hole could be reduced considerably, while at the same time a significant reduction in the notches on the strand surface could be achieved. Subsequent hot deformations showed no cracks after the first deformation stitch.

Claims (12)

1. A method for extruding molten metals, in particular alloys with a relatively high melting point, e.g. steel, wherein the molten metal is conveyed via at least one melt feed line (2), e.g. a duct, from a melt container (1), a pan or the like, to a substantially horizontally arranged chill (4) connected with the container in a fluid-tight manner and preferably fluid-cooled, through an outlet opening of a nozzle block (3), which opening has a smaller cross-sectional area than the chill (4), and the billet is drawn backwards out of the chill (4), preferably stepwise, possibly with a partial step, characterised in that the melt is conveyed substantially tangentially into a substantially horizontal part (8, 10) of the melt feed line (2), thus effecting rotation of the melt around the longitudinal axis (12) of the part (8), and thereafter the rotating melt is conveyed into the chill (4).
2. A method according to Claim 1, characterised in that.the melt feed line (2) has at least two cross-sections of different sizes and/or shapes in the region of the mouth, the corresponding portions (7, 8, 9, 10) of the melt feed line (2) opening into each other tangentially.
3. A metod according to Claim 1 or 2, characterised in that the melt feed line (2) has at least two different cross-sectional areas adjoining each other, the melt being conveyed more or less tangentially from that portion with the smaller cross-sectional area into that with the larger cross-sectional area.
4. A metod according to Claim 1, 2 or 3, characterised in that the speed of flow of the melt at each point in the melt feed line (2, 7, 8, 9, 10) is kept substantially constant on average over a period of time.
5. A metod according to any one of Claims 1 to 4, characterised in that the melt is conveyed by a substantially vertically arranged melt feed line (7, 9) from the melt container (1) into a melt feed line (8, 10) which is inclined relative to the feed line (7, 9) and preferably arranged substantially horizontally.
6. A method according to any one of Claims 1 to 5, characterised in that the melt in the substantially vertical melt feed line (7, 9) flows more quickly than in the melt feed line which is inclined to the latter, and is conveyed into the latter substantially tangentially to the cross- section of the same.
7. A device for extruding molten metals, in particular alloys with a relatively high melting point, e.g. steel, having a melt container (1), a chill (4) arranged substantially horizontally and preferably fluid-cooled, at least one melt feed line arranged therebetween, a nozzle bloack (24) having a smaller cross-sectional area than the chill (4), and a billet draw-off device, characterised in that the melt feed line (2) has at least two portions (7, 8, 9, 10) adjoining each other and of different shape, the first portion (7, 9), seen in the direction of flow of the melt, opening substantially tangentially into that portion (8, 10) which is arranged substantially horizontally upstream of the chill.
8. A device accoridng to Claim 7, characterised in that the portions (7, 8, 9, 10) opening tangentially into each other have different cross-sectional areas.
9. A device according to Claim 7 or 8, characterised in that the cross-sectional area of the portion (9) is smaller than that of the subsequent portion (10) arranged substantially horizontally upstream of the chill (4).
10. A device according to Claim 7, 8 or 9, characterised in that the axes of the melt feed line in the region of the change in the flow direction of the melt are skew, and preferably spaced at a normal distance from each other (a) of 1/2 to 1/6 of the inner diameter (d) of the melt feed line with the larger cross-sectional area.
11. A divice according to Claim 7, 8, 9 or 10, characterised in that the melt feed line (7) in the melt container (1) can be closed with a plug (6) acting on the inlet opening.
12. A device according to any one of Claims 7 to 11, characterised in that the melt feed line (7) has two portions substantially perpendicular to each other, one being connected with the chill and the other with the melt container.
EP19850890141 1984-06-26 1985-06-25 Method of and installation for continuous casting of metallic melts Expired EP0166718B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AT2060/84 1984-06-26
AT206084A AT387165B (en) 1984-06-26 1984-06-26 DEVICE FOR CONTINUOUSLY METALLIC MELTING

Publications (3)

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EP0166718A2 EP0166718A2 (en) 1986-01-02
EP0166718A3 EP0166718A3 (en) 1986-09-17
EP0166718B1 true EP0166718B1 (en) 1989-05-31

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EP19850890141 Expired EP0166718B1 (en) 1984-06-26 1985-06-25 Method of and installation for continuous casting of metallic melts

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JP (1) JPS619946A (en)
AT (1) AT387165B (en)
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* Cited by examiner, † Cited by third party
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US6298899B1 (en) * 1999-07-13 2001-10-09 Ford Global Tech., Inc. Water jacket core
CN115717208A (en) * 2021-08-24 2023-02-28 昆山晶微新材料研究院有限公司 Aviation aluminum alloy material and production method thereof

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1508799B1 (en) * 1965-10-08 1971-09-16 Calderon Wellman Ltd DEVICE FOR FEEDING A STEEL MELT TO CONTINUOUS CASTING CHILLES
DE1758575A1 (en) * 1967-06-29 1971-02-11 Koppers Co Inc Method and device for producing a cast metal strand
FR2213121B1 (en) * 1972-11-06 1975-04-25 Siderurgie Fse Inst Rech
CH558223A (en) * 1973-08-07 1975-01-31 Fischer Ag Georg PROCESS FOR SEPARATING SLAG AND OTHER CONTAMINATION FROM METAL MELT IN CONTINUOUS CASTING PLANTS AND CONTINUOUS CASTING PLANT FOR PERFORMING THE PROCESS.
DE2342820B1 (en) * 1973-08-24 1974-08-15 Kloeckner Werke Ag Immersion nozzle for a continuous casting mold
CH604956A5 (en) * 1974-12-24 1978-09-15 Fischer Ag Georg Runner system for vertically split casting moulds
US4202397A (en) * 1975-01-20 1980-05-13 Bethlehem Steel Corporation Method of continuously casting molten metal
NL7700977A (en) * 1976-02-24 1977-08-26 Alusuisse METHOD AND DEVICE FOR CONTINUOUS CASTING OF METAL MELT IN CASTING MOLDS.
AT343839B (en) * 1976-08-20 1978-06-26 Voest Ag METHOD AND DEVICE FOR CONTINUOUS CASTING OF A STEEL STRAND
SE410284B (en) * 1978-02-10 1979-10-08 Asea Ab PROCEDURE FOR REMOVAL OF METALLIC MELT AND DEVICE FOR IMPLEMENTATION OF THIS PROCEDURE
DE2825360C2 (en) * 1978-06-09 1983-10-27 Fried. Krupp Gmbh, 4300 Essen Induction heated trough for feeding metal into a continuous casting mold

Also Published As

Publication number Publication date
AT387165B (en) 1988-12-12
JPS619946A (en) 1986-01-17
DE3570613D1 (en) 1989-07-06
EP0166718A2 (en) 1986-01-02
EP0166718A3 (en) 1986-09-17
ATA206084A (en) 1988-05-15

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