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EP0961665A1 - How to avoid contact between oxygen and molten metal - Google Patents

How to avoid contact between oxygen and molten metal

Info

Publication number
EP0961665A1
EP0961665A1 EP98910649A EP98910649A EP0961665A1 EP 0961665 A1 EP0961665 A1 EP 0961665A1 EP 98910649 A EP98910649 A EP 98910649A EP 98910649 A EP98910649 A EP 98910649A EP 0961665 A1 EP0961665 A1 EP 0961665A1
Authority
EP
European Patent Office
Prior art keywords
casting
suction
chamber
inert gas
oxygen
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
EP98910649A
Other languages
German (de)
French (fr)
Other versions
EP0961665B1 (en
Inventor
Gerald Hohenbichler
Stefano Pellissetti
Romeo Capotosti
Giuseppe Guasto
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Primetals Technologies Austria GmbH
Acciai Speciali Terni SpA
Original Assignee
Voest Alpine Industrienlagenbau GmbH
Acciai Speciali Terni SpA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Voest Alpine Industrienlagenbau GmbH, Acciai Speciali Terni SpA filed Critical Voest Alpine Industrienlagenbau GmbH
Publication of EP0961665A1 publication Critical patent/EP0961665A1/en
Application granted granted Critical
Publication of EP0961665B1 publication Critical patent/EP0961665B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
    • B22D11/0622—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars formed by two casting wheels
    • 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
    • B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
    • B22D11/0637—Accessories therefor
    • B22D11/0697—Accessories therefor for casting in a protected atmosphere
    • 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
    • B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
    • B22D11/0637—Accessories therefor
    • B22D11/064—Accessories therefor for supplying molten metal
    • B22D11/0642—Nozzles
    • 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
    • B22D11/12—Accessories for subsequent treating or working cast stock in situ
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D27/00—Treating the metal in the mould while it is molten or ductile ; Pressure or vacuum casting
    • B22D27/003—Treating the metal in the mould while it is molten or ductile ; Pressure or vacuum casting by using inert gases

Definitions

  • the invention relates to a method for preventing the contact of oxygen with a molten metal during continuous casting, the molten metal flowing into a casting space delimited by walls and emerging from it as a strand, and a device for carrying out the method.
  • Continuous casting results in the accumulation of molten metal in the casting room, which must be protected against reoxidation and its bath level from excessive heat radiation.
  • the bath level is covered with casting powder or with an oil for this purpose.
  • the invention aims to avoid these disadvantages and difficulties and has the object to provide a method of the type described above and a device for continuous casting, with which contact of oxygen with a molten metal can be prevented, which completely prevents reoxidation, u .zw. even if there is severe wear on the gaps between the walls forming the casting space.
  • This object is achieved in a method of the type described in the introduction in that any gaps that may be trying to penetrate between the walls and / or oxygen adhering to the walls are suctioned off.
  • a particularly efficient removal of the oxygen can advantageously be achieved in that the suction in several from the outside to the inside Suction stages arranged one behind the other take place, whereby the suction is expediently carried out with decreasing pressure from stage to stage from the outside inwards towards the casting chamber.
  • the suction pressure in the suction stage closest to the casting chamber is set below 50 mbar, preferably below 10 mbar.
  • an inert gas is expediently allowed to flow against the wall directly adjacent to the suction zone closest to the casting chamber on a wall delimiting the casting chamber, the pressure of the inert gas advantageously being increased by at least 10 mbar, preferably by more than 200 mbar the pressure of the neighboring suction stage.
  • the inert gas is preferably blown against the wall in a plurality of inert gas stages which are arranged adjacent to the outside of the casting chamber.
  • the inert gas is expediently blown onto the wall at a speed of at least 0.5 m / s, at most 10 m / s, preferably at more than 2 m / s.
  • a casting method in which at least one wall is moved relative to the casting chamber in which at least one wall is moved relative to the casting chamber, according to a preferred embodiment, wall regions of this wall which are newly entering the casting chamber are freed of oxygen adhering to them by suction before the entry.
  • the continuous casting is then advantageously carried out in the roll casting process, preferably in the two-roll casting process, that is to say that roll casting processes with only one casting roll, as described, for example, in EP-B-0 040 072, are also suitable for the process according to the invention.
  • the method according to the invention can also be used when casting a molten metal on any moving heat sink, for example a caterpillar chain according to DE-A-36 02 594. It may also be for Chill molds with rigid walls are advantageous, for example, if the application of a mold powder is not possible or would be too expensive.
  • a device with which contact of oxygen with a molten metal can be prevented during continuous casting wherein a casting space bounded by walls is filled with molten metal and a strand emerges from the casting space via a pouring gap in the pouring space, is characterized in that any between adjacent ones Walls existing gaps a suction device is provided for trying to penetrate through the gaps and / or for oxygen adhering to the walls.
  • a device for the continuous casting of a metal strip preferably a steel strip, with two counter-rotating casting rolls with parallel adjacent roller axes and two side dams, which together form a casting space for the reception of molten metal and with a covering hood which is arranged above the casting space and this closes at the top, as well as with a sealing device that prevents the entry of air into the casting space along a gap formed by the cover and the rotating casting rollers
  • the object on which the invention is based is advantageously achieved in that the sealing device has at least one atmospheric side in the vicinity of the Gap is arranged between the rotating casting rolls and the cover and extending parallel to the roll axis suction chamber.
  • This sealing device has a particularly effective effect if it is formed by a plurality of suction chambers arranged next to one another in the circumferential direction of the casting rolls. It is advantageous here if each suction chamber is connected to an assigned suction pump or to a stage of a multi-stage suction pump via a suction line.
  • the sealing device is designed as a serial multi-chamber system. This measure reduces the suction pressure in the direction of movement of the casting rolls from the suction chamber to the suction chamber. By a Corresponding coordination of the number of suction chambers to the peripheral speed of the casting rolls, a complete removal of the entrained air can be achieved.
  • the sealing device is arranged at a defined distance from the casting roll surface and the gap formed by the sealing device and the casting roll surface is sealed at least on the input and output sides with touching seals, preferably brush or rubber lip seals.
  • At least one of the suction chambers is additionally equipped with an inert gas purge.
  • the device is improved in that an inert gas supply is arranged between the cover and the suction device, this inert gas supply being designed as a vacuum chamber with an opening directed against the casting rolls.
  • the opening is advantageously designed as a nozzle which is directed obliquely towards the casting roll surface and inclined to the adjacent suction chamber.
  • FIG. 1 shows a cross section through the two-roll zeng screenstrom with a sealing device according to a first embodiment
  • Fig. 2 shows a second embodiment of the sealing device according to the invention
  • FIG 3 shows a third embodiment of the sealing device according to the invention.
  • the two-roll casting installation as shown schematically in section in FIG. 1, has two driven casting rolls 1, 2, the roll axes 3, 4 of which are arranged parallel to one another and are arranged in a horizontal plane.
  • the two casting rolls 1, 2 rotating in opposite directions in the direction of the arrow 5, 6 are provided with internal cooling (not shown) for the casting roll shell, which forms the casting roll surface 7.
  • side dams 8 are arranged sufficiently close to the casting rolls 1, 2.
  • a casting chamber 9 is formed by the casting rolls 1, 2 and the side dams 8, into which melt 20 is introduced from a melt container or a distribution vessel (not shown) through a supply nozzle 11 provided with outlet openings 11, which forms a melt sump 12.
  • the casting chamber 9 is bounded at the top, with respect to the casting rollers 1, 2 and with respect to the side dams 8 by a cover 13 which has a refractory lining 14 on the melt side in order to protect the melt 20 against excessive heat losses and against reoxidation from the atmospheric oxygen.
  • a desired minimum gap 18 between the cover 13 and the casting rollers 1, 2 is set with a support device 15 for the cover 13, which is adjustable with respect to a stationary frame 16 with setting elements 17.
  • the cover 13 is penetrated by the feed nozzle 10, with the smallest possible gap being provided between these components, which may be covered by a seal.
  • a two-roll caster of this configuration it is possible to cast a thin metal strip, in particular a steel strip, in the thickness range from 1 mm to 12 mm, the melt 20 to be cast being introduced continuously into the casting space 9, as described at the beginning.
  • the casting rolls 1, 2 rotating and cooling in opposite directions are increasingly formed Stronger shells, which are connected in the narrowest cross section between the casting rolls to form a band formed by the casting rolls.
  • the thickness of the strip fed out by the casting rolls is determined by the distance between the two casting rolls.
  • a sealing device 23 formed by a suction chamber 24 is on the atmosphere side in the vicinity of the gap 18 and at a short distance from the casting roll surface 7 arranged.
  • the suction chamber 24 is open to the casting roll surface 7 and is connected to a suction line 25 and a suction pump, not shown.
  • the suction chamber 24 is formed in a simple manner by a U-profile open to the casting roll surface, which extends parallel to the roll axis 3, 4 at a short distance from the casting roll surface over the entire length of the casting roll.
  • the gap between the suction chamber 24 and the casting roll surface 7 is covered with seals attached to the U-profile and the casting roll surface 7 touching seals 27, which are preferably designed as brush or rubber lip seals.
  • the suction device 23 is formed by a plurality of suction chambers 24 arranged side by side in the circumferential direction of the casting rolls 1, 2, and each suction chamber is via an associated suction line 25, each with a stage of a multi-stage suction pump, not shown connected.
  • This designed as a serial multi-chamber sealing device 23 makes it possible to operate the introduced air in several suction stages with the chamber pressure gradually decreasing in the direction of casting.
  • the pressure in the last suction chamber 31 in the direction of casting rotation is set to a value below 50 mbar, preferably below 10 mbar, in order to achieve optimal air suction.
  • an inert gas supply 28 is additionally between the suction chamber 24 and the cover 13 arranged, which is formed by a vacuum chamber 29 and has an opening 32 directed towards the casting roll surface. In addition, it is connected to a supply line 30 for inert gas.
  • the vacuum chamber 29 is designed in the same way as the suction chamber 24, and both are combined in one structural unit in order to prevent entry of false air. For the same reason, the vacuum chamber 29 is connected to the cover 13 in an airtight manner.
  • the vacuum chamber 29 is formed with an outlet opening directed against the casting roller surface 7, the vacuum chamber being combined with the serial multi-chamber system of the sealing device 23 to form a structural unit and being sealed against air access.
  • Inert gas is introduced into the vacuum chamber 29 in order to build up a flow boundary layer of inert gas on the casting roll surface 7, which is introduced into the casting chamber 9 instead of the air through the gap 18 between the casting rolls 1, 2 and the covering hood 13.
  • the pressure in the vacuum chamber 29 is set at least 10 mbar, preferably more than 200 mbar, above the pressure of the upstream suction device 23.
  • FIG. 3 shows an embodiment in which a plurality of vacuum chambers 29, which are connected to a common inert gas supply 28, are arranged within a suction chamber 24, connected to a suction line 25, for the fresh air suction.
  • the inert gas pressure is set to a value above atmospheric pressure.
  • Last residues of the atmospheric oxygen adhering to the casting roll surface 7 in the boundary layer can be removed with the inert gas purging if the inert gas is blown directly against the casting roll surface 7 is, for which the flow velocity is set to at least 0.5 m / s, preferably to more than 2 m / s. Flow velocities of more than 10 m / s bring no additional effect.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
  • Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)
  • Investigating Or Analysing Materials By The Use Of Chemical Reactions (AREA)
  • Spark Plugs (AREA)
  • Coupling Device And Connection With Printed Circuit (AREA)
  • Manufacture Of Switches (AREA)

Abstract

Method of preventing contact of oxygen with a metal melt during continuous casting, the metal melt flows into a casting chamber bounded by rolls and a hood and leaves this chamber as a stream. To completely prevent contact of oxygen with the metal melt and thus reoxidation, oxygen attempting to enter via any gaps between the walls and/or adhering to the walls is removed by suction applied at a succession of suction stages at the periphery of each roll before a gap between the hood and the roll at the top of the casting chamber. Inert gas may then flow to the rolls near the gap.

Description

Verfahren zum Verhindern des Kontaktes von Sauerstoff mit einer MetallschmelzeProcess for preventing contact of oxygen with a molten metal
Die Erfindung betrifft ein Verfahren zum Verhindern des Kontaktes von Sauerstoff mit einer Metallschmelze beim Stranggießen, wobei die Metallschmelze in einen von Wänden begrenzten Gießraum einströmt und aus diesem als Strang austritt, sowie eine Vorrichtung zur Durchführung des Verfahrens.The invention relates to a method for preventing the contact of oxygen with a molten metal during continuous casting, the molten metal flowing into a casting space delimited by walls and emerging from it as a strand, and a device for carrying out the method.
Beim Stranggießen kommt es im Gießraum zur Ansammlung von Metallschmelze, die gegen Reoxidation und deren Badspiegel vor starker Wärmeabgabe durch Strahlung geschützt werden muß. Beim konventionellen Stranggießen wird zu diesem Zweck der Badspiegel mit Gießpulver oder mit einem Öl bedeckt.Continuous casting results in the accumulation of molten metal in the casting room, which must be protected against reoxidation and its bath level from excessive heat radiation. In conventional continuous casting, the bath level is covered with casting powder or with an oil for this purpose.
Zum Gießen dünner Bänder sind verschiedene Gießverfahren bekannt, bei denen der Gießraum nicht von starren Wänden, sondern von einer sich mit dem Strang bewegenden Wand oder von mehreren sich mit dem Strang bewegenden Wänden gebildet ist, beispielsweise von einer Raupenkette gemäß EP-A - 0 526886 oder von einer Walze gemäß EP-A - 0 568 211 oder EP-B - 0 040 072 oder von zwei sich gegenläufig bewegenden Gießwalzen gemäß US-A - 4,987,949 oder EP-B - 0 430841. Bei diesen Verfahren ist es nicht möglich, die Metallschmelze durch ein Gießpulver oder Öl zuverlässig gegen Reoxidation bzw. Wärmeabgabe zu schützen, wie dies bei Gießräumen bzw. Kokillen mit starren Wänden meist der Fall ist.Various casting methods are known for casting thin strips, in which the casting chamber is not formed by rigid walls, but by a wall moving with the strand or by a plurality of walls moving with the strand, for example by a caterpillar chain according to EP-A-0 526886 or from a roller according to EP-A - 0 568 211 or EP-B - 0 040 072 or from two counter-rotating casting rollers according to US-A - 4,987,949 or EP-B - 0 430841. With these methods it is not possible to use the Protect molten metal reliably against reoxidation or heat emission with a casting powder or oil, as is usually the case with casting rooms or molds with rigid walls.
Aus der EP-B - 0 430841 ist es bei einer Zweiwal zengießanlage bekannt, den Badspiegel durch Vorsehen einer Abdeckhaube vor zu starker Wärmeabgabe durch Strahlung und gegen Reoxidation zu schützen. Bei dieser Lösung hat sich jedoch herausgestellt, daß es an den Kontaktflächen zwischen Abdeckhaube und Gießwalzen sowohl an der Abdeckhaube als auch an den Gießwalzen zu starkem Verschleiß kommt und durch thermische Verformung der Bauteile der Durchtritt von Luft und damit von Sauerstoff durch Spalte zwischen den den Gießraum begrenzenden Wänden nicht verhindert werden kann. Es kommt zu einer Reoxidation der Schmelze mit allen Nachteilen. Um den Durchtritt von Luft durch den Spalt zwischen Abdeckhaube und Gießwalzen zu minimieren, wird in der US-A - 4,987,949 und der EP-A - 0 714 716 vorgeschlagen, in einen definierten Spalt zwischen Abdeckhaube und Gießwalzen ein inertes Gas, vorzugsweise Stickstoff oder Argon einzublasen und so eine Sperre gegen eindringende Luft zu errichten. Diese Maßnahme reicht jedoch nicht aus, um den Zutritt von Luft in den Gießraum und damit zum Badspiegel restlos zu verhindern, so daß einerseites nach wie vor an der Badoberfläche Metalloxide gebildet werden, die zu Fehlstellen im Inneren des Metallbandes führen. Andererseits werden an der Oberfläche der sich bildenden Strangschale Metalloxide gebildet bzw. diffundiert Sauerstoff in die Randschicht des Metallbandes und bildet dort Einschlüsse, was die Rißanfälligkeit steigert. Trotz der Inertgaszuführung wird in der sogenannten laminaren Unterschicht der Strömungsgrenzschicht die in der Mikrorauhigkeit der Walzenoberfläche anhaftende Luft in den Gießraum eingeschleppt. Diese Unterschicht haftet in der Mikrorauhigkeit der Walzenoberfläche und läßt sich weder durch berührende gleitende Dichtungen noch durch berührungslose Dichtungen abstreifen.From EP-B - 0 430841 it is known in a two-roll zengießanlage to protect the bath level by providing a cover against excessive heat emission by radiation and against reoxidation. With this solution, however, it has been found that there is heavy wear on the contact surfaces between the covering hood and casting rollers, both on the covering hood and on the casting rollers, and the thermal deformation of the components causes air and thus oxygen to pass through gaps between the casting space bounding walls cannot be prevented. The melt reoxidizes with all disadvantages. In order to minimize the passage of air through the gap between the cover and casting rolls, US Pat. No. 4,987,949 and EP-A - 0 714 716 propose an inert gas, preferably nitrogen or argon, in a defined gap between the cover and casting rolls to blow in and thus establish a barrier against the ingress of air. However, this measure is not sufficient to completely prevent the entry of air into the casting chamber and thus to the bath level, so that on the one hand metal oxides are still formed on the bath surface, which lead to defects in the interior of the metal strip. On the other hand, metal oxides are formed on the surface of the strand shell that forms or oxygen diffuses into the edge layer of the metal strip and forms inclusions there, which increases the susceptibility to cracking. Despite the supply of inert gas, the air adhering to the micro-roughness of the roll surface is dragged into the casting chamber in the so-called laminar lower layer of the flow boundary layer. This sub-layer adheres to the micro-roughness of the roller surface and cannot be wiped off by touching sliding seals or by non-contact seals.
Die Erfindung bezweckt die Vermeidung dieser Nachteile und Schwierigkeiten und stellt sich die Aufgabe, ein Verfahren der eingangs beschriebenen Art sowie eine Vorrichtung zum Stranggießen, mit der ein Kontakt von Sauerstoff mit einer Metallschmelze verhindert werden kann, zu schaffen, welche eine Reoxidation gänzlich verhindert, u.zw. auch dann, wenn es zu einem starken Verschleiß an den zwischen den den Gießraum bildenden Wänden vorhandenen Spalten kommt. Insbesondere soll es möglich sein, auch die sogenannte laminare Unterschicht der an den den Gießraum bildenden Wänden anhaftenden bzw. mitgeschleppten Luftschicht zu entfernen.The invention aims to avoid these disadvantages and difficulties and has the object to provide a method of the type described above and a device for continuous casting, with which contact of oxygen with a molten metal can be prevented, which completely prevents reoxidation, u .zw. even if there is severe wear on the gaps between the walls forming the casting space. In particular, it should also be possible to remove the so-called laminar underlayer of the air layer adhering to the walls forming the casting space or being carried along.
Diese Aufgabe wird bei einem Verfahren der eingangs beschriebenen Art dadurch gelöst, daß über allfällige Spalte zwischen den Wänden einzudringen versuchender und/oder an den Wänden anhaftender Sauerstoff abgesaugt wird.This object is achieved in a method of the type described in the introduction in that any gaps that may be trying to penetrate between the walls and / or oxygen adhering to the walls are suctioned off.
Eine besonders effiziente Entfernung des Sauerstoffs läßt sich vorteilhaft dadurch erzielen, daß das Absaugen in mehreren von außen nach innen zum Gießraum hin hintereinander angeordneten Absaugstufen erfolgt, wobei zweckmäßig das Absaugen mit von Stufe zu Stufe von außen nach innen zum Gießraum hin abnehmendem Druck erfolgt.A particularly efficient removal of the oxygen can advantageously be achieved in that the suction in several from the outside to the inside Suction stages arranged one behind the other take place, whereby the suction is expediently carried out with decreasing pressure from stage to stage from the outside inwards towards the casting chamber.
Hierbei wird gemäß einer bevorzugten Ausführungsform der Absaugdruck in der dem Gießraum nächstliegenden Absaugstufe unter 50 mbar, vorzugsweise unter 10 mbar, eingestellt.According to a preferred embodiment, the suction pressure in the suction stage closest to the casting chamber is set below 50 mbar, preferably below 10 mbar.
Um einen Druckausgleich gegenüber dem Gießraum sicherzustellen, wird zweckmäßig unmittelbar benachbart zur dem Gießraum nächstliegenden Absaugzone an einer den Gießraum begrenzenden Wand ein Inertgas gegen die Wand strömen gelassen, wobei vorteilhaft der Druck des Inertgases um mindestens 10 mbar, vorzugsweise um mehr als 200 mbar, über dem Druck der benachbarten Absaugstufe liegt.In order to ensure pressure equalization with respect to the casting chamber, an inert gas is expediently allowed to flow against the wall directly adjacent to the suction zone closest to the casting chamber on a wall delimiting the casting chamber, the pressure of the inert gas advantageously being increased by at least 10 mbar, preferably by more than 200 mbar the pressure of the neighboring suction stage.
Vorzugsweise wird das Inertgas in mehreren von außen nach innen zum Gießraum hin benachbart angeordneten Inertgasstufen gegen die Wand geblasen.The inert gas is preferably blown against the wall in a plurality of inert gas stages which are arranged adjacent to the outside of the casting chamber.
Zweckmäßig wird das Inertgas mit einer Geschwindigkeit von mindestens 0,5 m/s, maximal 10 m/s, vorzugsweise mit mehr als 2 m/s, auf die Wand aufgeblasen.The inert gas is expediently blown onto the wall at a speed of at least 0.5 m / s, at most 10 m / s, preferably at more than 2 m / s.
Bei einem Gießverfahren, bei dem mindestens eine Wand gegenüber dem Gießraum bewegt wird, werden gemäß einer bevorzugten Ausführungsform in den Gießraum neu eintretende Wandbereiche dieser Wand vor dem Eintrten von an diesen anhaftendem Sauerstoff durch Absaugen des Sauerstoffes befreit. Das Stranggießen erfolgt dann vorteilhaft im Walzgießverfahren, vorzugsweise im Zweiwalzengießverfahren, d.h., daß auch Walzgießverfahren mit nur einer Gießwalze, wie beispielsweise in der EP-B - 0 040 072 beschrieben, für das erfindungsgemäße Verfahren in Frage kommen. Selbstverständlich läßt sich auch das erfindungsgemäße Verfahren beim Gießen einer Metallschmelze auf einem beliebigen bewegten Kühlkörper, beispielsweise einer Raupenkette gemäß der DE-A - 36 02 594, anwenden. Unter Umständen ist es auch für Kokillen mit starren Wänden von Vorteil, z.B., wenn das Aufbringen eines Gießpulvers nicht möglich ist oder zu aufwendig wäre.In a casting method in which at least one wall is moved relative to the casting chamber, according to a preferred embodiment, wall regions of this wall which are newly entering the casting chamber are freed of oxygen adhering to them by suction before the entry. The continuous casting is then advantageously carried out in the roll casting process, preferably in the two-roll casting process, that is to say that roll casting processes with only one casting roll, as described, for example, in EP-B-0 040 072, are also suitable for the process according to the invention. Of course, the method according to the invention can also be used when casting a molten metal on any moving heat sink, for example a caterpillar chain according to DE-A-36 02 594. It may also be for Chill molds with rigid walls are advantageous, for example, if the application of a mold powder is not possible or would be too expensive.
Eine Vorrichtung, mit der ein Kontakt von Sauerstoff mit einer Metallschmelze beim Stranggießen verhindert werden kann, wobei ein von Wänden begrenzter Gießraum mit Metallschmelze gefüllt ist und aus dem Gießraum ein Strang über einen Gießspalt des Gießraumes austritt, ist dadurch gekennzeichnet, daß an allfälligen zwischen benachbarten Wänden vorhandenen Spalten eine Absaugeinrichtung für über die Spalte einzudringen versuchenden und/oder für an den Wänden anhaftenden Sauerstoff vorgesehen ist.A device with which contact of oxygen with a molten metal can be prevented during continuous casting, wherein a casting space bounded by walls is filled with molten metal and a strand emerges from the casting space via a pouring gap in the pouring space, is characterized in that any between adjacent ones Walls existing gaps a suction device is provided for trying to penetrate through the gaps and / or for oxygen adhering to the walls.
Bei einer Vorrichtung zum kontinuierlichen Gießen eines Metallbandes, vorzugsweise eines Stahlbandes, mit zwei gegenläufig rotierenden Gießwalzen mit parallel nebeneinanderliegenden Walzenachsen und zwei Seitendämmen, die zusammen einen Gießraum für die Aufnahme von schmelzflüssigem Metall bilden und mit einer Abdeckhaube, die oberhalb des Gießraumes angeordnet ist und diesen nach oben abschließt, sowie mit einer Abdichteinrichtung, die den Zutritt von Luft entlang eines von der Abdeckhaube und den rotierenden Gießwalzen gebildeten Spaltes in den Gießraum verhindert, wird die der Erfindung zugrundeliegende Aufgabe vorteilhaft dadurch gelöst, daß die Abdichteinrichtung von mindestens einer atmospährenseitig im Nahbereich des Spaltes zwischen den rotierenden Gießwalzen und der Abdeckhaube angeordneten und sich parallel zur Walzenachse erstreckenden Absaugkammer gebildet ist.In a device for the continuous casting of a metal strip, preferably a steel strip, with two counter-rotating casting rolls with parallel adjacent roller axes and two side dams, which together form a casting space for the reception of molten metal and with a covering hood which is arranged above the casting space and this closes at the top, as well as with a sealing device that prevents the entry of air into the casting space along a gap formed by the cover and the rotating casting rollers, the object on which the invention is based is advantageously achieved in that the sealing device has at least one atmospheric side in the vicinity of the Gap is arranged between the rotating casting rolls and the cover and extending parallel to the roll axis suction chamber.
Besonders effektiv wirkt diese Abdichteinrichtung, wenn sie von mehreren nebeneinander in Umfangsrichtung der Gießwalzen angeordneten Absaugkammern gebildet ist. Hierbei ist es von Vorteil, wenn jede Absaugkammer über eine Absaugleitung mit einer zugeordneten Absaugpumpe oder einer Stufe einer mehrstufigen Absaugpumpe verbunden ist. Nach einer konstruktiv einfachen Ausführungsform ist die Abdichteinrichtung als serielles Mehrkammersystem ausgebildet. Durch diese Maßnahme nimmt der Saugdruck in Bewegungsrichtung der Gießwalzen von Absaugkammer zu Absaugkammer ab. Durch eine entsprechende Abstimmung der Anzahl der Absaugkammern auf die Umfangsgeschwindigkeit der Gießwalzen ist eine vollständige Entfernung der mitgeschleppten Luft erzielbar.This sealing device has a particularly effective effect if it is formed by a plurality of suction chambers arranged next to one another in the circumferential direction of the casting rolls. It is advantageous here if each suction chamber is connected to an assigned suction pump or to a stage of a multi-stage suction pump via a suction line. According to a structurally simple embodiment, the sealing device is designed as a serial multi-chamber system. This measure reduces the suction pressure in the direction of movement of the casting rolls from the suction chamber to the suction chamber. By a Corresponding coordination of the number of suction chambers to the peripheral speed of the casting rolls, a complete removal of the entrained air can be achieved.
Nach einer verbesserten Ausführungsform ist die Abdichteinrichtung im definierten Abstand zur Gießwalzenoberfläche angeordnet und der von der Abdichteinrichtung und der Gießwalzenoberfläche gebildete Spalt zumindest eingangs- und ausgangsseitig mit berührenden Dichtungen, vorzugsweise Bürsten- oder Gummi lippendichtungen abgedichtet. Dadurch wird der Luftzutritt bereits vor der ersten Absaugkammer weitgehend auf die mit der Grenzschicht mitgeschleppte Luft begrenzt.According to an improved embodiment, the sealing device is arranged at a defined distance from the casting roll surface and the gap formed by the sealing device and the casting roll surface is sealed at least on the input and output sides with touching seals, preferably brush or rubber lip seals. As a result, the air access is largely limited to the air entrained with the boundary layer even before the first suction chamber.
Nach einer anderen Ausführungsform ist zumindest eine der Absaugkammern zusätzlich mit einer Inertgasspülung ausgestattet.According to another embodiment, at least one of the suction chambers is additionally equipped with an inert gas purge.
Verbessert wird die Einrichtung dadurch, daß zwischen der Abdeckhaube und der Absaugeinrichtung eine Inertgaszuführung angeordnet ist, wobei diese Inertgaszuführung als Unterdruckkammer mit einer gegen die Gießwalzen gerichteten Öffnung ausgebildet ist. Vorteilhaft ist die Öffnung als Düse ausgebildet, die schräg gegen die Gießwalzenoberfläche und zur benachbarten Absaugkammer geneigt gerichtet ist. Durch diese Maßnahme wird eine walzennahe Inertgasschicht auf die Gießwalze aufgebracht und so ein hervorragender Schutz vor Sauerstoff- bzw. Luftzutritt erzeugt. Wird eine Inertgasschicht von einigen Millimetern Stärke auf der Gießwalze aufgebracht und ein Inertgas verwendet, welches schwerer als Luft ist, so ist es nicht notwendig, daß die Abdeckhaube unmittelbar an die Inertgaszuführung und Absaugeinrichtung anschließt.The device is improved in that an inert gas supply is arranged between the cover and the suction device, this inert gas supply being designed as a vacuum chamber with an opening directed against the casting rolls. The opening is advantageously designed as a nozzle which is directed obliquely towards the casting roll surface and inclined to the adjacent suction chamber. As a result of this measure, an inert gas layer close to the roll is applied to the casting roll, thus providing excellent protection against the ingress of oxygen or air. If an inert gas layer of a few millimeters thick is applied to the casting roll and an inert gas which is heavier than air is used, it is not necessary for the cover hood to be connected directly to the inert gas supply and suction device.
Weitere Merkmale und Vorteile ergeben sich aus der nachstehenden Beschreibung der Vorrichtung und des Verfahrens zum Gießen eines Metallbandes in mehreren Ausführungsformen:Further features and advantages result from the following description of the device and the method for casting a metal strip in several embodiments:
Fig. 1 zeigt einen Querschnitt durch die Zweiwal zengießanlage mit einer Abdichteinrichtung nach einer ersten Ausführungsform; Fig. 2 zeigt eine zweite Ausführungsform der erfindungsgemäßen Abdichteinrichtung;Fig. 1 shows a cross section through the two-roll zengießanlage with a sealing device according to a first embodiment; Fig. 2 shows a second embodiment of the sealing device according to the invention;
Fig. 3 zeigt eine dritte Ausführungsform der erfindungsgemäßen Abdichteinrichtung.3 shows a third embodiment of the sealing device according to the invention.
Die Zweiwalzengießanlage, wie sie in Fig. 1 schematisch im Schnitt dargestellt ist, weist zwei angetriebene Gießwalzen 1, 2 auf, deren parallel zueinander angeordnete Walzenachsen 3, 4 in einer horizontalen Ebene angeordnet sind. Die beiden gegenläufig in Pfeilrichtung 5, 6 rotierenden Gießwalzen 1, 2 sind mit einer nicht dargestellten Innenkühlung für den Gießwalzenmantel versehen, der die Gießwalzenoberfläche 7 bildet. Stirnseitig sind Seitendämme 8 hinreichend nahe an den Gießwalzen 1, 2 angeordnet. Von den Gießwalzen 1, 2 und den Seitendämmen 8 wird ein Gießraum 9 gebildet, in welchen von einem nicht dargestellten Schmelzenbehälter oder einem Verteilergefäß durch eine mit Austrittsöffnungen 11 versehene Zufuhrdüse 10 Schmelze 20 eingebracht wird, die einen Schmelzensumpf 12 bildet. Der Gießraum 9 ist nach oben, gegenüber den Gießwalzen 1, 2 und gegenüber den Seitendämmen 8 mit einer Abdeckhaube 13 begrenzt, die schmelzenseitig eine feuerfeste Auskleidung 14 aufweist, um die Schmelze 20 vor zu großen Wärmeverlusten und gegen Reoxidation aus dem Luftsauerstoff zu schützen. Mit einer Trageinrichtung 15 für die Abdeckhaube 13, die gegenüber einem stationären Gestell 16 mit Einstellelementen 17 justierbar ist, wird ein gewünschter minimaler Spalt 18 zwischen der Abdeckhaube 13 und den Gießwalzen 1, 2 eingestellt. Die Abdeckhaube 13 ist von der Zufuhrdüse 10 durchsetzt, wobei zwischen diesen Bauteilen ein möglichst geringer Spalt vorgesehen ist, der gegebenenfa ls von einer Dichtung abgedeckt wird.The two-roll casting installation, as shown schematically in section in FIG. 1, has two driven casting rolls 1, 2, the roll axes 3, 4 of which are arranged parallel to one another and are arranged in a horizontal plane. The two casting rolls 1, 2 rotating in opposite directions in the direction of the arrow 5, 6 are provided with internal cooling (not shown) for the casting roll shell, which forms the casting roll surface 7. On the face side, side dams 8 are arranged sufficiently close to the casting rolls 1, 2. A casting chamber 9 is formed by the casting rolls 1, 2 and the side dams 8, into which melt 20 is introduced from a melt container or a distribution vessel (not shown) through a supply nozzle 11 provided with outlet openings 11, which forms a melt sump 12. The casting chamber 9 is bounded at the top, with respect to the casting rollers 1, 2 and with respect to the side dams 8 by a cover 13 which has a refractory lining 14 on the melt side in order to protect the melt 20 against excessive heat losses and against reoxidation from the atmospheric oxygen. A desired minimum gap 18 between the cover 13 and the casting rollers 1, 2 is set with a support device 15 for the cover 13, which is adjustable with respect to a stationary frame 16 with setting elements 17. The cover 13 is penetrated by the feed nozzle 10, with the smallest possible gap being provided between these components, which may be covered by a seal.
Mit einer Zweiwalzengießanlage dieser Konfiguration ist es möglich, ein dünnes Metallband, insbesondere ein Stahlband, im Dickenbereich von 1 mm bis 12 mm zu gießen, wobei die zu vergießende Schmelze 20, wie eingangs beschrieben, kontinuierlich in den Gießraum 9 eingebracht wird. An den gegensinnig rotierenden und gekühlten Gießwalzen 1, 2 bilden sich zunehmend stärker werdende Strangschalen aus, die im engsten Querschnitt zwischen den Gießwalzen zu einem von den Gießwalzen geformten Band verbunden werden. Die Dicke des von den Gießwalzen ausgeförderten Bandes wird vom Abstand der beiden Gießwalzen bestimmt.With a two-roll caster of this configuration, it is possible to cast a thin metal strip, in particular a steel strip, in the thickness range from 1 mm to 12 mm, the melt 20 to be cast being introduced continuously into the casting space 9, as described at the beginning. The casting rolls 1, 2 rotating and cooling in opposite directions are increasingly formed Stronger shells, which are connected in the narrowest cross section between the casting rolls to form a band formed by the casting rolls. The thickness of the strip fed out by the casting rolls is determined by the distance between the two casting rolls.
Um den Zutritt von Luft entlang eines von der Abdeckhaube 13 und den rotierenden Gießwalzen 1, 2 gebildeten Spalten 18 in den Gießraum zu verhindern, ist eine von einer Absaugkammer 24 gebildete Abdichteinrichtung 23 atmosphärenseitig im Nahbereich des Spaltes 18 und im geringen Abstand von der Gießwalzenoberfläche 7 angeordnet. Die Absaugkammer 24 ist zur Gießwalzenoberfläche 7 offen und mit einer Absaugleitung 25 sowie einer nicht dargestellten Absaugpumpe verbunden. Die Absaugkammer 24 ist in einfacher Weise von einem zur Gießwalzenoberfläche offenen U-Profil gebildet, welches sich parallel zur Walzenachse 3, 4 im geringen Abstand von der Gießwalzenoberfläche über die gesamte Gießwalzenlänge erstreckt. Der Spalt zwischen Absaugkammer 24 und der Gießwalzenoberfläche 7 ist mit an den U-Profil schenkein befestigten die Gießwalzenoberfläche 7 berührenden Dichtungen 27 abgedeckt, die vorzugsweise als Bürsten- oder Gummi lippendichtungen ausgebildet sind.In order to prevent air from entering the casting space along a gap 18 formed by the covering hood 13 and the rotating casting rolls 1, 2, a sealing device 23 formed by a suction chamber 24 is on the atmosphere side in the vicinity of the gap 18 and at a short distance from the casting roll surface 7 arranged. The suction chamber 24 is open to the casting roll surface 7 and is connected to a suction line 25 and a suction pump, not shown. The suction chamber 24 is formed in a simple manner by a U-profile open to the casting roll surface, which extends parallel to the roll axis 3, 4 at a short distance from the casting roll surface over the entire length of the casting roll. The gap between the suction chamber 24 and the casting roll surface 7 is covered with seals attached to the U-profile and the casting roll surface 7 touching seals 27, which are preferably designed as brush or rubber lip seals.
Nach einer weiteren Ausführungsform, wie sie in Fig. 2 dargestellt ist, wird die Absaugeinrichtung 23 von mehreren nebeneinander in Umfangsrichtung der Gießwalzen 1, 2 angeordneten Absaugkammern 24 gebildet und jede Absaugkammer ist über eine zugeordnete Absaugleitung 25 mit je einer Stufe einer nicht dargestellten mehrstufigen Absaugpumpe verbunden. Diese als serielles Mehrkammersystem ausgebildete Abdichteinrichtung 23 ermöglicht es, die eingeschleppte Luft in mehreren Absaugstufen mit in Gießwal zendrehrichtung stufenweise abnehmenden Kammerdruck zu betreiben. Der Druck in der in Gießwal zendrehrichtung letzten Absaugkammer 31 ist zur Erzielung einer optimalen Luftabsaugung auf einen Wert unter 50 mbar, vorzugsweise unter 10 mbar, eingestellt.According to a further embodiment, as shown in Fig. 2, the suction device 23 is formed by a plurality of suction chambers 24 arranged side by side in the circumferential direction of the casting rolls 1, 2, and each suction chamber is via an associated suction line 25, each with a stage of a multi-stage suction pump, not shown connected. This designed as a serial multi-chamber sealing device 23 makes it possible to operate the introduced air in several suction stages with the chamber pressure gradually decreasing in the direction of casting. The pressure in the last suction chamber 31 in the direction of casting rotation is set to a value below 50 mbar, preferably below 10 mbar, in order to achieve optimal air suction.
In der Ausführungsform gemäß Fig. 1 ist zusätzlich zwischen der Absaugkammer 24 und der Abdeckhaube 13 eine Inertgaszuführung 28 angeordnet, die von einer Unterdruckkammer 29 gebildet ist und einen gegen die Gießwalzenoberfläche gerichtete Öffnung 32 aufweist. Zusätzlich ist sie mit einer Zufuhrleitung 30 für Inertgas verbunden. Im Detail ist die Unterdruckkammer 29 gleichermaßen wie die Absaugkammer 24 ausgebildet und um Falschluftzutritt zu vermeiden, sind beide in einer Baueinheit zusammengefaßt. Aus gleichem Grund ist auch die Unterdruckkammer 29 luftdicht mit der Abdeckhaube 13 verbunden.In the embodiment according to FIG. 1, an inert gas supply 28 is additionally between the suction chamber 24 and the cover 13 arranged, which is formed by a vacuum chamber 29 and has an opening 32 directed towards the casting roll surface. In addition, it is connected to a supply line 30 for inert gas. In detail, the vacuum chamber 29 is designed in the same way as the suction chamber 24, and both are combined in one structural unit in order to prevent entry of false air. For the same reason, the vacuum chamber 29 is connected to the cover 13 in an airtight manner.
In der Ausführungsform, wie sie in Fig. 2 dargestellt ist, ist die Unterdruckkammer 29 mit einer gegen die Gießwalzenoberfl che 7 gerichteten Austrittsöffnung ausgebildet, wobei die Unterdruckkammer mit dem seriellen Mehrkammersystem der Abdichteinrichtung 23 zu einer Baueinheit zusammengefaßt und gegen Luftzutritt abgedichtet ist.In the embodiment, as shown in FIG. 2, the vacuum chamber 29 is formed with an outlet opening directed against the casting roller surface 7, the vacuum chamber being combined with the serial multi-chamber system of the sealing device 23 to form a structural unit and being sealed against air access.
Inertgas wird in die Unterdruckkammer 29 eingebracht, um an der Gießwalzenoberfläche 7 eine Strömungsgrenzschicht aus Inertgas aufzubauen, die durch den Spalt 18 zwischen den Gießwalzen 1, 2 und der Abdeckhaube 13 anstelle der Luft in den Gießraum 9 eingebracht wird. Hierzu genügt es, wenn der Druck in der Unterdruckkammer 29 um mindestens 10 mbar, vorzugsweise um mehr als 200 mbar, über dem Druck der vorgelagerten Absaugeinrichtung 23 eingestellt wird.Inert gas is introduced into the vacuum chamber 29 in order to build up a flow boundary layer of inert gas on the casting roll surface 7, which is introduced into the casting chamber 9 instead of the air through the gap 18 between the casting rolls 1, 2 and the covering hood 13. For this it is sufficient if the pressure in the vacuum chamber 29 is set at least 10 mbar, preferably more than 200 mbar, above the pressure of the upstream suction device 23.
In Fig. 3 ist eine Ausführungsform dargestellt, bei der mehrere Unterdruckkammern 29, die mit einer gemeinsamen Inertgaszuführung 28 verbunden sind, innerhalb einer mit einer Absaugleitung 25 verbundenen Absaugkammer 24 für die Frischluftabsaugung angeordnet sind. Bei der in Gießwalzendrehrichtung letzten und direkt vor der Abdeckhaube 13 positionierten Unterdruckkammer 29a wird im Gegensatz zu den vorgeordneten Unterdruckkammern 29 der Inertgasdruck auf einen Wert über dem Atmosphärendruck eingestellt.FIG. 3 shows an embodiment in which a plurality of vacuum chambers 29, which are connected to a common inert gas supply 28, are arranged within a suction chamber 24, connected to a suction line 25, for the fresh air suction. In the vacuum chamber 29a, which is last in the casting roll rotation direction and positioned directly in front of the cover 13, in contrast to the upstream vacuum chambers 29, the inert gas pressure is set to a value above atmospheric pressure.
Letzte Reste des in der Grenzschicht an der Gießwalzenoberfläche 7 anhaftenden Luftsauerstoffes können mit der Inertgasspülung entfernt werden, wenn das Inertgas direkt gegen die Gießwalzenoberfl che 7 geblasen wird, wozu die Anströmgeschwindigkeit auf mindestens 0,5 m/s, vorzugsweise auf mehr als 2 m/s, eingestellt wird. Anströmgeschwindigkeiten von mehr als 10 m/s bringen keinen zusätzlichen Effekt. Last residues of the atmospheric oxygen adhering to the casting roll surface 7 in the boundary layer can be removed with the inert gas purging if the inert gas is blown directly against the casting roll surface 7 is, for which the flow velocity is set to at least 0.5 m / s, preferably to more than 2 m / s. Flow velocities of more than 10 m / s bring no additional effect.

Claims

Patentansprüche: Claims:
1. Verfahren zum Verhindern des Kontaktes von Sauerstoff mit einer Metallschmelze (20) beim Stranggießen, wobei die Metallschmelze (20) in einen von Wänden (1, 2, 13) begrenzten Gießraum einströmt und aus diesem als Strang austritt, dadurch gekennzeichnet, daß über allfällige Spalte (18) zwischen den Wänden (1, 2, 13) einzudringen versuchender und/oder an den Wänden (1, 2) anhaftender Sauerstoff abgesaugt wird.1. A method for preventing the contact of oxygen with a molten metal (20) during continuous casting, the molten metal (20) flowing into a wall of (1, 2, 13) limited casting space and emerging from it as a strand, characterized in that about any gaps (18) between the walls (1, 2, 13) trying to penetrate and / or oxygen adhering to the walls (1, 2) is suctioned off.
2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß das Absaugen in mehreren von außen nach innen zum Gießraum hin hintereinander angeordneten Absaugstufen erfolgt.2. The method according to claim 1, characterized in that the suction takes place in several suction stages arranged one behind the other from the outside towards the casting chamber.
3. Verfahren nach Anspruch 2, dadurch gekennzeichnet, daß das Absaugen mit von Stufe zu Stufe von außen nach innen zum Gießraum hin abnehmendem Druck erfolgt.3. The method according to claim 2, characterized in that the suction is carried out with decreasing pressure from level to level from the outside inwards towards the casting space.
4. Verfahren nach Anspruch 2 oder 3, dadurch gekennzeichnet, daß der Absaugdruck in der dem Gießraum nächstliegenden Absaugstufe unter 50 mbar, vorzugsweise unter 10 mbar, eingestellt wird.4. The method according to claim 2 or 3, characterized in that the suction pressure in the next to the casting chamber suction stage is set below 50 mbar, preferably below 10 mbar.
5. Verfahren nach einem oder mehreren der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß unmittelbar benachbart zur dem Gießraum nächstliegenden Absaugzone an einer den Gießraum begrenzenden Wand (1, 2) ein Inertgas gegen die Wand (1, 2) strömen gelassen wird.5. The method according to one or more of claims 1 to 4, characterized in that an inert gas is allowed to flow against the wall (1, 2) immediately adjacent to the suction zone closest to the casting chamber on a wall delimiting the casting chamber (1, 2).
6. Verfahren nach Anspruch 5, dadurch gekennzeichnet, daß der Druck des Inertgases um mindestens 10 mbar, vorzugsweise um mehr als 200 mbar, über dem Druck der benachbarten Absaugstufe liegt.6. The method according to claim 5, characterized in that the pressure of the inert gas by at least 10 mbar, preferably by more than 200 mbar, is above the pressure of the adjacent suction stage.
7. Verfahren nach Anspruch 5 oder 6, dadurch gekennzeichnet, daß das Inertgas in mehreren von außen nach innen zum Gießraum hin benachbart angeordneten Inertgasstufen gegen die Wand geblasen wird. 7. The method according to claim 5 or 6, characterized in that the inert gas is blown against the wall in a plurality of inert gas stages arranged adjacent to the outside of the casting chamber.
8. Verfahren nach einem oder mehreren der Ansprüche 5 bis 7, dadurch gekennzeichnet, daß das Inertgas mit einer Geschwindigkeit von mindestens 0,5 m/s, maximal 10 m/s, vorzugsweise mit mehr als 2 m/s, auf die Wand (1, 2) aufgeblasen wird.8. The method according to one or more of claims 5 to 7, characterized in that the inert gas at a speed of at least 0.5 m / s, maximum 10 m / s, preferably with more than 2 m / s, on the wall ( 1, 2) is inflated.
9. Verfahren nach einem oder mehreren der Ansprüche 1 bis 8, dadurch gekennzeichnet, daß mindestens eine Wand (1, 2) gegenüber dem Gießraum bewegt wird und in den Gießraum neu eintretende Wandbereiche dieser Wand (1, 2) vor dem Eintreten von an diesen anhaftendem Sauerstoff durch Absaugen des Sauerstoffes befreit werden.9. The method according to one or more of claims 1 to 8, characterized in that at least one wall (1, 2) is moved relative to the casting space and in the casting space newly entering wall areas of this wall (1, 2) before the entry of these adhering oxygen can be freed by suction of the oxygen.
10. Verfahren nach Anspruch 9, dadurch gekennzeichnet, daß das Stranggießen im Walzgießverfahren, vorzugsweise Zweiwalzen-Gießverfahren, durchgeführt wird.10. The method according to claim 9, characterized in that the continuous casting in the roll casting process, preferably two-roll casting process, is carried out.
11. Vorrichtung zum Verhindern des Kontaktes von Sauerstoff mit einer Metallschmelze beim Stranggießen, wobei ein von Wänden begrenzter Gießraum mit Metallschmelze gefüllt ist und aus dem Gießraum ein Strang über einen Gießspalt des Gießraumes austritt, dadurch gekennzeichnet, daß an anfälligen zwischen benachbarten Wänden vorhandenen Spalten eine Absaugeinrichtung für über die Spalte einzudringen versuchenden und/oder für an den Wänden anhaftenden Sauerstoff vorgesehen ist.11. Device for preventing the contact of oxygen with a molten metal during continuous casting, wherein a casting space delimited by walls is filled with molten metal and a strand emerges from the casting space through a casting gap of the casting space, characterized in that there are gaps between fragile walls between adjacent walls Suction device is provided for trying to penetrate through the gaps and / or for oxygen adhering to the walls.
12. Vorrichtung nach Anspruch 11, zum kontinuierlichen Gießen eines Metallbandes, vorzugsweise Stahlbandes, mit zwei gegenläufig rotierenden Gießwalzen (1, 2), mit parallel nebeneinanderliegenden Walzenachsen (3, 4) und zwei Seitendämmen (8), die zusammen einen Gießraum (9) für die Aufnahme von schmelzflüssigem Metall bilden und mit einer Abdeckhaube (13), die oberhalb des Gießraumes (9) angeordnet ist und diesen nach oben abschließt, sowie mit einer Abdichteinrichtung (23), die den Zutritt von Luft entlang eines von der Abdeckhaube (13) und den rotierenden Gießwalzen (1, 2) gebildeten Spaltes (18) in den Gießraum (9) verhindert, dadurch gekennzeichnet, daß die Abdichteinrichtung (23) von mindestens einer atmospährenseitig im Nahbereich des Spaltes (18) zwischen den rotierenden Gießwalzen (1, 2) und der Abdeckhaube (13) angeordneten und sich parallel zur Walzenachse erstreckenden Absaugkammer (24) gebildet ist.12. The device according to claim 11, for the continuous casting of a metal strip, preferably steel strip, with two counter-rotating casting rolls (1, 2), with parallel roller axes (3, 4) and two side dams (8), which together form a casting space (9) form for the reception of molten metal and with a cover (13) which is arranged above the casting space (9) and closes it off at the top, and with a sealing device (23) which prevents the entry of air along one of the cover (13 ) and the rotating casting rolls (1, 2) formed gap (18) in the casting space (9), characterized in that the sealing device (23) of at least one on the atmosphere side The vicinity of the gap (18) between the rotating casting rolls (1, 2) and the cover (13) is arranged and extends parallel to the roll axis of the suction chamber (24).
13. Vorrichtung nach Anspruch 11 oder 12, dadurch gekennzeichnet, daß diese Abdichteinrichtung (23) von mehreren nebeneinander in Umfangsrichtung der Gießwalzen angeordneten Absaugkammern (24) gebildet ist.13. The apparatus according to claim 11 or 12, characterized in that this sealing device (23) is formed by a plurality of suction chambers (24) arranged side by side in the circumferential direction of the casting rolls.
14. Vorrichtung nach einem der Ansprüche 11 bis 13, dadurch gekennzeichnet, daß jede Absaugkammer (24) über eine Absaugleitung (25) mit einer zugeordneten Absaugpumpe oder einer Stufe einer mehrstufigen Absaugpumpe verbunden ist.14. Device according to one of claims 11 to 13, characterized in that each suction chamber (24) via a suction line (25) is connected to an associated suction pump or a stage of a multi-stage suction pump.
15. Vorrichtung nach einem der Ansprüche 11 bis 14, dadurch gekennzeichnet, daß die Abdichteinrichtung (23) als serielles Mehrkammersystem ausgebildet ist.15. Device according to one of claims 11 to 14, characterized in that the sealing device (23) is designed as a serial multi-chamber system.
16. Vorrichtung nach einem der Ansprüche 11 bis 15, dadurch gekennzeichnet, daß die Abdichteinrichtung (23) im definierten Abstand zur Gießwalzenoberfl che (7) angeordnet ist und der von der Abdichteinrichtung und der Gießwalzenoberfläche gebildete Spalt (18) zumindest eingangs- und ausgangsseitig mit berührenden Dichtungen (27), vorzugsweise Bürsten- oder Gummi lippendichtungen abgedichtet ist.16. Device according to one of claims 11 to 15, characterized in that the sealing device (23) is arranged at a defined distance from the Gießwalzenoberfl surface (7) and the gap formed by the sealing device and the casting roll surface (18) at least on the input and output sides Touching seals (27), preferably brush or rubber lip seals is sealed.
17. Vorrichtung nach einem der Ansprüche 11 bis 16, dadurch gekennzeichnet, daß zumindest eine der Absaugkammern (24) zusätzlich mit einer Inertgasspülung ausgestattet ist.17. Device according to one of claims 11 to 16, characterized in that at least one of the suction chambers (24) is additionally equipped with an inert gas purge.
18. Vorrichtung nach einem der Ansprüche 11 bis 17, dadurch gekennzeichnet, daß zwischen der Abdeckhaube (13) und der Absaugkammer (24) eine Inertgaszuführung (28) angeordnet ist. 18. Device according to one of claims 11 to 17, characterized in that an inert gas supply (28) is arranged between the cover (13) and the suction chamber (24).
19. Vorrichtung nach Anspruch 18, dadurch gekennzeichnet, daß die Inertgaszuführung (28) als Unterdruckkammer (29) mit einer gegen die Gießwalzenoberfl che gerichteten Öffnung (32) ausgebildet ist.19. The apparatus according to claim 18, characterized in that the inert gas supply (28) is designed as a vacuum chamber (29) with a surface directed against the casting roller surface (32).
20. Vorrichtung nach Anspruch 20, dadurch gekennzeichnet, daß die Öffnung (31) als Düse ausgebildet ist, die schräg gegen die Gießwalzenoberfläche und zur benachbarten Absaugkammer (24) geneigt gerichtet ist.20. The apparatus according to claim 20, characterized in that the opening (31) is designed as a nozzle which is inclined towards the casting roll surface and to the adjacent suction chamber (24).
21. Vorrichtung nach einem der Ansprüche 11 bis 20, dadurch gekennzeichnet, daß zwischen Absaugkammer (24) und Abdeckhaube (13) eine Lamellendichtung angeordnet ist. 21. Device according to one of claims 11 to 20, characterized in that a lamellar seal is arranged between the suction chamber (24) and cover (13).
EP98910649A 1997-02-14 1998-02-12 How to avoid contact between oxygen and molten metal Expired - Lifetime EP0961665B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
IT97RM000082A IT1290932B1 (en) 1997-02-14 1997-02-14 PROCEDURE AND DEVICE FOR PREVENTING OXYGEN CONTACT WITH A MOLTEN METAL MASS.
ITRM970082 1997-02-14
PCT/EP1998/000788 WO1998035773A1 (en) 1997-02-14 1998-02-12 How to avoid contact between oxygen and molten metal

Publications (2)

Publication Number Publication Date
EP0961665A1 true EP0961665A1 (en) 1999-12-08
EP0961665B1 EP0961665B1 (en) 2001-06-20

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US (1) US6415849B1 (en)
EP (1) EP0961665B1 (en)
JP (1) JP2001512371A (en)
KR (1) KR100525035B1 (en)
CN (1) CN1072056C (en)
AT (1) ATE202304T1 (en)
AU (1) AU744243B2 (en)
BR (1) BR9807225A (en)
CA (1) CA2281703A1 (en)
DE (1) DE59800886D1 (en)
ES (1) ES2160406T3 (en)
ID (1) ID22429A (en)
IT (1) IT1290932B1 (en)
PL (1) PL335252A1 (en)
RU (1) RU2199416C2 (en)
UA (1) UA48296C2 (en)
WO (1) WO1998035773A1 (en)

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JP2002113555A (en) * 2000-10-10 2002-04-16 Castrip Llc Twin-roll type continuous caster and its using method
AT414103B (en) * 2003-05-19 2006-09-15 Voest Alpine Ind Anlagen METHOD FOR PRODUCING A CAST METAL STRIP AND TWO ROLLER CASTING DEVICE THEREFOR
CN103451371B (en) * 2013-09-10 2016-01-20 泰州鑫宇精密铸造有限公司 Induction furnace molten steel covers blowing argon pouring technology and device
AT520033B1 (en) 2017-06-02 2022-01-15 Asmag Holding Gmbh extrusion machine
CN113231610B (en) * 2021-04-30 2022-09-23 中冶赛迪工程技术股份有限公司 Arc vibration thin strip continuous casting method and thin strip continuous casting and rolling production line

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AU744243B2 (en) 2002-02-21
BR9807225A (en) 2000-04-25
ITRM970082A1 (en) 1998-08-14
ATE202304T1 (en) 2001-07-15
PL335252A1 (en) 2000-04-10
RU2199416C2 (en) 2003-02-27
IT1290932B1 (en) 1998-12-14
CN1072056C (en) 2001-10-03
KR100525035B1 (en) 2005-11-01
UA48296C2 (en) 2002-08-15
EP0961665B1 (en) 2001-06-20
ES2160406T3 (en) 2001-11-01
WO1998035773A1 (en) 1998-08-20
DE59800886D1 (en) 2001-07-26
CN1247488A (en) 2000-03-15
AU6496398A (en) 1998-09-08
CA2281703A1 (en) 1998-08-20
KR20000070345A (en) 2000-11-25
ID22429A (en) 1999-10-14
JP2001512371A (en) 2001-08-21
US6415849B1 (en) 2002-07-09

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