EP0637477B1 - Supplying system in a continuous aluminium casting system - Google Patents

Supplying system in a continuous aluminium casting system Download PDF

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Publication number
EP0637477B1
EP0637477B1 EP94108061A EP94108061A EP0637477B1 EP 0637477 B1 EP0637477 B1 EP 0637477B1 EP 94108061 A EP94108061 A EP 94108061A EP 94108061 A EP94108061 A EP 94108061A EP 0637477 B1 EP0637477 B1 EP 0637477B1
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EP
European Patent Office
Prior art keywords
nozzle
plug
inlet
section
supplying system
Prior art date
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Expired - Lifetime
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EP94108061A
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German (de)
French (fr)
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EP0637477A2 (en
EP0637477A3 (en
Inventor
C.J. Dipl.-Ing. Moritz
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Vereinigte Aluminium Werke AG
Vaw Aluminium AG
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Vereinigte Aluminium Werke AG
Vaw Aluminium AG
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Publication of EP0637477A2 publication Critical patent/EP0637477A2/en
Publication of EP0637477A3 publication Critical patent/EP0637477A3/en
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22DCASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D41/00Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
    • B22D41/50Pouring-nozzles
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22DCASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/16Controlling or regulating processes or operations
    • B22D11/18Controlling or regulating processes or operations for pouring
    • B22D11/181Controlling or regulating processes or operations for pouring responsive to molten metal level or slag level
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22DCASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/10Supplying or treating molten metal
    • B22D11/103Distributing the molten metal, e.g. using runners, floats, distributors
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22DCASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D41/00Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
    • B22D41/14Closures
    • B22D41/16Closures stopper-rod type, i.e. a stopper-rod being positioned downwardly through the vessel and the metal therein, for selective registry with the pouring opening

Definitions

  • the invention relates to an inlet system for continuous aluminum casting plants, consisting of a gutter, one in gutter 1 used inlet nozzle 2, in which a plug 3 for regulation of the melt inlet 4 is inserted, the stopper 3 the narrowest cross section of the feed nozzle 2 is the melt feed closes and a control system with which the immersion depth the stopper is controllable within predetermined limits and a method for regulating an enema system.
  • the object of the invention is therefore in the enema system To optimize aluminum continuous casting plants so that under Maintaining the essential installations of negative pressure is minimized at the nozzle inlet and at the nozzle outlet and optimized the flow conditions in the inlet nozzle become.
  • a procedure for operating the enema system is said to reduce the vortex formation in the melt, so that both on the melt surface in the gutter as well no melt formation in the mold in the mold occur.
  • the nozzle contour according to the invention provides that in the The narrowest cross section is in the middle of the inlet nozzle and thus the highest speed in the middle of the nozzle is produced.
  • the nozzle shape prevents flow which could reduce the cross-section through which avoided.
  • the nozzle is thus evenly over the flows through the entire cross-section, resulting in a optimal volume flow can be set.
  • the inlet system consists of one in the channel 1 used inlet nozzle 2 into which a plug 3 for regulation of the melt inlet 4 is used.
  • a metal level H is formed above the inlet nozzle 2 in the Channel 1, which is preferably at least 5 cm.
  • the melt reaches the mold 5 via the pouring nozzle, where it is formed into an ingot 6, which is placed on the runner 7 is held.
  • a lowering device 9 the ingot 6 is down from the mold 5 pulled out.
  • nozzles 2 and plugs 3 are shown in FIG remove. It can be seen that the cross sections at the nozzle inlet (X) and nozzle outlet (Y) in relation to the other cross sections the inlet nozzle are chosen large, so that there are low Flow velocities occur.
  • the inlet nozzle according to the invention consists of two Cut A1, A2 from the narrowest cross section of the nozzle to the Nozzle entry or exit are measured.
  • section A2 In the upper part of the nozzle 2 (section A2) forms between Plug 3 and inner wall of the inlet nozzle from an annular space D, the narrows in the direction of flow.
  • the pressure ratios are also increased by an Level difference - in the example 26 cm and 34 cm - hardly changed.
  • the closely spaced curves for different level differences show that the flow conditions are very stable and even with high negative pressure the flow in the nozzle does not stop. It follows that the available cross section is relatively even is flowed through and no speed peaks occur.
  • FIGS. 6a, b and 5a, b known inlet systems exemplified.
  • a downward closing inlet system according to FIG. 4a the vacuum at the nozzle outlet can no longer be reduced as the available cross section at the nozzle outlet very strong due to the stall under the stopper is reduced.
  • FIG. 4b shows a known upward closing inlet system shown.
  • the negative pressure increases increasing level difference strongly (see Figure 5b).
  • This has the consequence that the above the nozzle inlet in the Gutter standing metal column and the associated static Pressure is insufficient to reach the nozzle inlet to compensate for the resulting negative pressure.
  • Pressure curves depend on the position of the measuring points dependent.
  • the representations in Figure 5a, b are as look at two-dimensional representations and therefore say nothing about the uniformity of the flow over the Circumference of the inlet nozzle. As shown at the beginning, but can be uneven with conventional infeed systems keiten occur over the circumference of the inlet nozzle, whereby Speed peaks arise, which in turn create the negative pressure increase.
  • the volume flow can be dosed much more precisely and that Avoid occurrence of instabilities. It showed the glass model that an optimized nozzle also over the Flow is relatively even.
  • the known inlet system tends to Turbulence formation. This is shown in FIG. 7 and is explained in more detail below.
  • the melt 4 reaches the inlet nozzle in the direction of the arrow through the channel 1 2.
  • the resulting at the nozzle inlet and outlet The melt surface becomes underpressure from the air pressure dented, which can tear open the oxide layer and Oxide or dirt particles are sucked into the melt can.
  • the non-deformable impurities are in the solidification front installed. In the later rolling process they come to the surface and lead to tearing open of the rolled strip or damage to the rolls.
  • FIG 8 is a mechanical control of the mold casting system shown schematically for aluminum ingots. Via a float 14, which on the metal surface of the Barrens is positioned using a mechanical redirector 15 of the stopper 3 by means of a push rod 16 moved up or down.
  • the term "swimmer” is used for a piece of refractory material that is on the metal surface floats and the metal stand via a lever reports. In the present case, it becomes the annular gap between nozzle and stopper enlarged or reduced, each after which direction the melt level from the set point deviates. The feed rate of the molten metal is thus regulated by different plug heights.
  • the metal level in the mold 5 can be different Reasons fluctuate. For example, the inclination of the Melting furnace not continuously, so that gushing occurs in the channel 1. Even the metal stand in the gutter is usually regulated with a float, so that normally two control systems are coupled together are. This leads to a dynamic control behavior, that during the pouring phase of a constant correction of the each plug height required.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)
  • Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
  • Molds, Cores, And Manufacturing Methods Thereof (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Coating With Molten Metal (AREA)
  • Manufacture And Refinement Of Metals (AREA)

Description

Die Erfindung betrifft ein Einlaufsystem für Aluminiumstranggußanlagen, bestehend aus einer Rinne, einer in die Rinne 1 eingesetzten Zulaufdüse 2, in die ein Stopfen 3 zur Regulierung des Schmelzezulaufs 4 eingesetzt ist, wobei der Stopfen 3 am engsten Querschnitt der Zulaufdüse 2 den Schmelzezulauf verschließt und einem Regelsystem, mit dem die Eintauchtiefe des Stopfens innerhalb vorgegebener Grenzen steuerbar ist sowie ein Verfahren zur Regelung eines Einlaufsystemes.The invention relates to an inlet system for continuous aluminum casting plants, consisting of a gutter, one in gutter 1 used inlet nozzle 2, in which a plug 3 for regulation of the melt inlet 4 is inserted, the stopper 3 the narrowest cross section of the feed nozzle 2 is the melt feed closes and a control system with which the immersion depth the stopper is controllable within predetermined limits and a method for regulating an enema system.

Die Regelung des Schmelzezulaufs mit Hilfe von Düse und Stopfen ist aus verschiedenen Veröffentlichungen bekannt. So ist beispielsweise von der Deutschen Gesellschaft für Metallkunde e.V. ein Symposium unter dem Titel "Stranggießen-Schmelzen-Gießen-Überwachen" veranstaltet worden, bei dem das Prinzip der Gießspiegelregelung nach dem Wirbelstromprinzip erläutert wurde. Bei den 1986 herausgegebenen Vortragstexten findet sich auf Seite 331 die Abbildung eines Regelsystems unter Verwendung von Düsen und Stopfen. Die Düse ist am Boden einer Rinne befestigt und ragt mit ihrem unteren Ende in die Kokille hinein.The regulation of the melt feed with the help of nozzle and plug is known from various publications. So is for example from the German Society for Metallurgy e.V. a symposium entitled "Continuous casting-melting-casting-monitoring" has been held where the principle of the mold level control according to the eddy current principle explained has been. The lecture texts published in 1986 include on page 331 the illustration of a control system using of nozzles and plugs. The nozzle is at the bottom of a gutter attached and protrudes with its lower end into the mold inside.

Ändert sich unter bestimmten Voraussetzungen die Geschwindigkeit der Aluminiumschmelze in der Einlaufdüse, so verändert sich auch der statische Druck. Bei sehr hohen Geschwindigkeiten der Aluminiumschmelze werden bei den dann auftretenden Unterdrucken am Düseneintritt oder Düsenaustritt Oxyd- und schmutzteilchen von der Metalloberfläche der Rinne oder des Barrens in die Schmelze eingesogen, was sich nachteilig bei der erzeugten Barrenqualität bemerkbar macht. The speed changes under certain conditions the molten aluminum in the inlet nozzle, so changed static pressure. At very high speeds of the aluminum melt are then those that occur Negative pressure at the nozzle inlet or nozzle outlet particles of dirt from the metal surface of the gutter or Barrens sucked into the melt, which is disadvantageous the quality of the bars produced.

Aufgabe der Erfindung ist es daher, das Einlaufsystem bei Aluminiumstranggußanlagen derart zu optimieren, daß unter Beibehaltung der wesentlichen Installationen der Unterdruck am Düseneintritt und am Düsenaustritt minimiert wird und die Strömungsverhältnisse in der Zulaufdüse optimiert werden. Ein Verfahren zum Betrieb des Einlaufsystems soll die Wirbelbildung in der Schmelze herabsetzen, so daß sowohl an der Schmelzeoberfläche in der Rinne als auch an der Schmelzeoberfläche in der Kokille keine Wirbelbildungen auftreten.The object of the invention is therefore in the enema system To optimize aluminum continuous casting plants so that under Maintaining the essential installations of negative pressure is minimized at the nozzle inlet and at the nozzle outlet and optimized the flow conditions in the inlet nozzle become. A procedure for operating the enema system is said to reduce the vortex formation in the melt, so that both on the melt surface in the gutter as well no melt formation in the mold in the mold occur.

Diese Aufgabe wird erfindungsgemäß durch die in den Ansprüchen angegebenen Merkmale gelöst. Es hat sich gezeigt, daß durch eine besondere Formgebung der Innenkontur der Düse sowie durch die Einhaltung bestimmter Eintauchtiefen in die oberhalb des Sumpfes sich ausbildende Schmelzzone das Mitreißen von Oxyd- und anderen Schmutzteilchen von der Metalloberfläche vermieden werden kann. Ferner muß für einen ausreichenden Metallstand in der Rinne gesorgt werden.Im ersten Schritt wird der am Düsenaustritt herrschende Unterdruck minimiert und dann die Eintauchtiefe so gemessen, daß eine Metallsäule von mindestens 2 cm den verbleibenden Unterdruck kompensiert.This object is achieved by the claims specified features solved. It has shown, that by a special shape of the inner contour of the Nozzle and by adhering to certain immersion depths into the melting zone that forms above the sump the entrainment of oxide and other dirt particles from the metal surface can be avoided. Furthermore, for sufficient metal level in the gutter The first step is the one at the nozzle outlet Vacuum minimized and then the immersion depth like this measured that a metal column of at least 2 cm remaining negative pressure compensated.

Die erfindungsgemäße Düsenkontur sieht vor, daß in der Mitte der Zulaufdüse der engste Querschnitt vorliegt und damit die höchste Geschwindigkeit in der Mitte der Düse erzeugt wird. Durch die Düsenform werden Strömungsabrisse, die den durchströmten Querschnitt verringern könnten, vermieden. Die Düse wird somit gleichmäßig über den gesamten Querschnitt durchströmt, wodurch sich ein optimaler Volumenstrom einstellen läßt.The nozzle contour according to the invention provides that in the The narrowest cross section is in the middle of the inlet nozzle and thus the highest speed in the middle of the nozzle is produced. The nozzle shape prevents flow which could reduce the cross-section through which avoided. The nozzle is thus evenly over the flows through the entire cross-section, resulting in a optimal volume flow can be set.

Bei den herkömmlichen Rinnenanordnungen ergeben sich am Einlaufsystem unterschiedliche Strömungsverhältnisse, je nachdem, welche Düsenseite von der in der Rinne fließenden Schmelze zuerst angeströmt wird. Unter bestimmmten Voraussetzungen führt dies bei herkömmlichen Einlaufsystemen zu einer ungleichmäßigen Verteilung der Flüssigkeitsströmung an der Düseninnenwand, mit der Folge, daß an bestimmten Düsenquerschnitten sehr große Strömungsgeschwindigkeiten und an anderen Stellen ein Strömungsschatten entsteht. Diese Zustände störten bisher die Gleichmäßigkeit der Strömung und wirkten sich auch auf die Einlauf- und Auslaufverhältnisse an der Zufuhrdüse aus.In the conventional channel arrangements result in Inlet system different flow conditions, each according to which side of the nozzle is flowing from the channel Melt is poured on first. Under certain conditions this leads to conventional infeed systems an uneven distribution of the liquid flow on the inner wall of the nozzle, with the result that certain Nozzle cross sections very high flow velocities and in other places a flow shadow is created. These conditions have so far disturbed the uniformity of the Flow and also affected the inlet and outlet conditions at the feed nozzle.

Zusammenfassend lassen sich die erfindungsgemäßen Merkmale wie folgt darstellen:

  • 1. Ausbildung der Düse derart, daß am Düseneintritt und am Düsenaustritt nur geringe Unterdrucke entstehen.
  • 2. Ausbildung der Düsenkonfiguration derart, daß die Düse über den Querschnitt gleichmäßig durchströmt wird und die Strömung an keiner Stelle abreißt.
  • 3. Drosselung der Strömung im mittleren Bereich der Düse, sodaß die vorhandene Strömungsenergie vermindert wird und an den Ein- und Austrittsenden der Düse praktisch keine Turbulenz auftritt.
  • The features according to the invention can be summarized as follows:
  • 1. Formation of the nozzle in such a way that only slight negative pressures arise at the nozzle inlet and outlet.
  • 2. Formation of the nozzle configuration in such a way that the cross-section flows through the nozzle uniformly and the flow does not stop at any point.
  • 3. Throttling the flow in the middle area of the nozzle so that the existing flow energy is reduced and practically no turbulence occurs at the inlet and outlet ends of the nozzle.
  • Im folgenden wird die Erfindung anhand mehrerer Ausführungsbeispiele näher erläutert. Es zeigen:

    Figur 1
    Gesamtansicht eines erfindungsgemäßen Einlaufsystem
    Figur 2
    Erfindungsgemäße Zulaufdüse mit Stopfen im Querschnitt
    Figur 3
    Druckverlauf in einem erfindungusgemäßen Einlaufsystem (Wassermodell)
    Figur 4
    Düsen/Stopfensystem nach dem Stand der Technik
    Figur 5
    Druckverlauf bei einem herkömmlichen Einlaufsystem im Wassermodell
    Figur 6
    Schematische Darstellung einer elektronischen Gießspiegelregelung
    Figur 7
    Gesamtansicht eines Einlaufsystems nach dem Stand der Technik
    Figur 8
    Schematische Darstellung einer mechanischen Gießspiegelregelung
    The invention is explained in more detail below with the aid of several exemplary embodiments. Show it:
    Figure 1
    General view of an enema system according to the invention
    Figure 2
    Inlet nozzle according to the invention with stopper in cross section
    Figure 3
    Pressure curve in an inlet system according to the invention (water model)
    Figure 4
    State-of-the-art nozzle / plug system
    Figure 5
    Pressure curve in a conventional inlet system in the water model
    Figure 6
    Schematic representation of an electronic mold level control
    Figure 7
    General view of an intake system according to the state of the art
    Figure 8
    Schematic representation of a mechanical mold level control

    Nach Figur 1 besteht das Einlaufsystem aus einer in die Rinne 1 eingesetzten Zulaufdüse 2, in die ein Stopfen 3 zur Regulierung des Schmelzezulaufs 4 eingesetzt ist. Am Düseneintritt über der Zulaufdüse 2 bildet sich ein Metallstand H in der Rinne 1 aus, der vorzugsweise mindestens 5 cm beträgt.According to Figure 1, the inlet system consists of one in the channel 1 used inlet nozzle 2 into which a plug 3 for regulation of the melt inlet 4 is used. At the nozzle inlet A metal level H is formed above the inlet nozzle 2 in the Channel 1, which is preferably at least 5 cm.

    Über die Gießdüse gelangt die Schmelze in die Kokille 5, wo sie zu einem Barren 6 geformt wird, der auf dem Angußstein 7 gehalten wird. Durch Absenken eines Gießtisches 8 mittels Absenkvorrichtung 9 wird der Barren 6 nach unten aus der Kokille 5 herausgezogen.The melt reaches the mold 5 via the pouring nozzle, where it is formed into an ingot 6, which is placed on the runner 7 is held. By lowering a casting table 8 using a lowering device 9 the ingot 6 is down from the mold 5 pulled out.

    Die Formen von Düsen 2 und Stopfen 3 sind aus der Figur 2 zu entnehmen. Man erkennt, daß die Querschnitte am Düsenein- (X) und Düsenaustritt (Y) im Verhältnis zu den übrigen Querschnitten der Einlaufdüse groß gewählt sind, damit dort geringe Strömungsgeschwindigkeiten auftreten. The shapes of nozzles 2 and plugs 3 are shown in FIG remove. It can be seen that the cross sections at the nozzle inlet (X) and nozzle outlet (Y) in relation to the other cross sections the inlet nozzle are chosen large, so that there are low Flow velocities occur.

    Die erfindungsgemäße Zulaufdüse besteht gemäß Figur 2 aus zwei Abscbnitten A1, A2, die vom engsten Querschnitt der Düse zum Düsenein- bzw. zum Düsenaustritt gemessen werden.According to FIG. 2, the inlet nozzle according to the invention consists of two Cut A1, A2 from the narrowest cross section of the nozzle to the Nozzle entry or exit are measured.

    Im oberen Teil der Düse 2 (Abschnitt A2) bildet sich zwischen Stopfen 3 und Innenwand der Zulaufdüse ein Ringraum D aus, der sich in Strömungsrichtung verengt.In the upper part of the nozzle 2 (section A2) forms between Plug 3 and inner wall of the inlet nozzle from an annular space D, the narrows in the direction of flow.

    Im unteren Teil der zulaufdüse 2 (Abschnitt A1) bildet sich zwischen Stopfen 3 und der Innenwand der Düse 2 nach Durchtritt durch den engsten Querschnitt ein Ringraum E aus, der sich zum Düsenaustritt hin erweitert. Die Erweiterung wächst mit zunehmender Annäherung an die Spitze S des Stopfens 3. Forms in the lower part of the inlet nozzle 2 (section A1) between plug 3 and the inner wall of the nozzle 2 after passage through the narrowest cross-section an annular space E, which widens towards the nozzle outlet. The expansion is growing with increasing approach to the tip S of the plug 3.

    Aus Figur 2 ist auch zu erkennen, wie der Stopfen 3 in die Düse 2 eintaucht. Der zwischen der Düse 2 und dem Stopfen 3 verbleibende Raum ist als Ringspalt C anzusehen und ist so ausgelegt, daß die Strömung den gesamten Querschnitt gleichmäßig ausfüllt. Von der Einlaufseite aus gesehen verjüngt sich der Ringspalt C, sodaß sich im strömenden Metall ein Staudruck aufbaut, der einer Verringerung des statischen Drucks in der Schmelze entgegenwirkt.From Figure 2 can also be seen how the plug 3 in the Immerses nozzle 2. The between the nozzle 2 and the Plug 3 remaining space is to be regarded as an annular gap C. and is designed so that the flow is the entire cross section fills evenly. From the inlet side seen the annular gap C tapers, so that in pouring metal builds up a back pressure, which is a reduction counteracts the static pressure in the melt.

    Im fast parallelen Teil des Ringspaltes C wird die für die Drosselung nötige Reibung erzeugt. Der Ringspalt C erweitert sich sodann geringfügig zum Stopfen 3 hin, sodaß sich die Strömung hier besser an den Stopfen 3 anlegt. Bei abnehmendem Querschnitt tritt durch die sich verjüngende Düse 2 eine Vergleichmäßigung der Strömung über den Querschnitt auf.In the almost parallel part of the annular gap C the for Throttling creates the necessary friction. The annular gap C expanded then slightly towards the plug 3, so that the flow here fits better on the stopper 3. At decreasing cross section occurs through the tapered Nozzle 2 an equalization of the flow over the cross section on.

    Hinter der engsten Stelle, etwa in der Düsenmitte, erweitert sich der Querschnitt, sodaß die Strömung ohne Abriß wieder abgebremst wird. Um auch an dem Stopfen 2 einen Strömungsabriß zu vermeiden, ist dieser an der Spitze zu einem Radius von im Beispiel 11,5 mm ausgezogen.Expanded behind the narrowest point, for example in the middle of the nozzle the cross section so that the flow without Demolition is slowed down again. To also on the plug 2 to avoid a stall, this is the Tip extended to a radius of 11.5 mm in the example.

    Zur Überprüfung der tatsächlichen Strömungsverhältnisse in der erfindungsgemäßen Düse wurde ein Wassermodell des bei der Herstellung eines Walzbarrens herrschenden Zustandes geschaffen. In diesem Wassermodell konnten die Verhältnisse in der Rinne, in der Düse und im Walzbarren, bei verschiedenen Düsen-Stopfen-Systemen simuliert werden. Mit diesem Wassermodell wurden die Druckverläufe im optimierten Einlaufsystem untersucht. Das Ergebnis ist in Figur 3 dargestellt. To check the actual flow conditions in the nozzle of the invention was a water model of the the production of a rolling ingot prevailing condition created. In this water model the conditions in the trough, in the nozzle and in the rolled bar, at different nozzle-plug systems can be simulated. With this water model, the pressure profiles were optimized Inlet system examined. The result is in Figure 3 shown.

    Man erkennt, daß am Düseneintritt (Düsenlänge = 0) ein positiver oder nur leicht negativer Druck herrscht. In der Düsenmitte werden durch die hohen Strömungsgeschwindigkeiten sehr hohe Unterdrucke erreicht. Am engsten Querschnitt werden hohe Unterdrucke gemessen, die zeigen, daß die Strömung nicht abreißt, sondern an den Wandungen anliegt. Danach erfolgt innerhalb kürzester Zeit ein Abbau der sehr hohen Unterdrucke, sodaß am Düsenaustritt bei etwa 17 cm Düsenlänge nur noch sehr geringe Unterdrucke verbleiben.It can be seen that at the nozzle inlet (nozzle length = 0) there is positive or only slightly negative pressure. In the The middle of the nozzle is due to the high flow velocities very high negative pressure reached. Narrowest cross section high negative pressures are measured, which show that the flow does not stop, but lies against the walls. Thereafter, it is dismantled within a very short time the very high negative pressure, so that at the nozzle outlet about 17 cm nozzle length only very low negative pressure remain.

    Die Druckverhältnisse werden auch durch einen vergrößerten Niveauunterschied - im Beispiel 26 cm und 34 cm - kaum verändert. Die dicht beieinander liegenden Kurven für verschiedene Niveauunterschiede zeigen, daß die Strömungszustände sehr stabil sind und auch bei hohen Unterdrucken die Strömung in der Düse nicht abreißt. Daraus folgt, daß der zur Verfügung stehende Querschnitt relativ gleichmäßig durchströmt wird und dabei keine Geschwindigkeitsspitzen auftreten.The pressure ratios are also increased by an Level difference - in the example 26 cm and 34 cm - hardly changed. The closely spaced curves for different level differences show that the flow conditions are very stable and even with high negative pressure the flow in the nozzle does not stop. It follows that the available cross section is relatively even is flowed through and no speed peaks occur.

    In den Figuren 6a, b und 5a, b sind die Druckverläufe bekannter Einlaufsysteme exemplarisch dargestellt. Bei einem nach unten schließenden Einlaufsystem gemäß Figur 4a kann der Unterdruck am Düsenaustritt nicht mehr abgebaut werden, da der verfügbare Querschnitt am Düsenaustritt durch den Strömungsabriß unter dem Stopfen sehr stark verkleinert wird. Somit entstehen hohe Unterdrucke am Düsenaustritt, die nicht mehr durch eine Vergrößerung der Eintauchtiefe der Düse kompensiert werden können (siehe Figur 5a).The pressure profiles are shown in FIGS. 6a, b and 5a, b known inlet systems exemplified. At a downward closing inlet system according to FIG. 4a the vacuum at the nozzle outlet can no longer be reduced as the available cross section at the nozzle outlet very strong due to the stall under the stopper is reduced. This creates high negative pressures on Nozzle outlet, which can no longer be achieved by enlarging the Immersion depth of the nozzle can be compensated (see Figure 5a).

    In Figur 4b ist ein bekanntes nach oben schließendes Einlaufsystem dargestellt. Hier Steigt der Unterdruck bei zunehmendem Niveauunterschied stark an (siehe Figur 5b). Dies hat zur Folge, daß die über dem Düseneintritt in der Rinne stehende Metallsäule und der damit verbundene statische Druck nicht ausreicht, um den am Düseneintritt entstehenden Unterdruck zu kompensieren. Ferner entsteht unter dem Stopfen ein Strömungsabriß, der den zur Verfügung stehenden Querschnitt vermindert. Bei größerem Niveauunterschied kann sich dieser Strömungsabriß bis zum Düsenaustritt hin auswirken, sodaß dort eine Verstärkung des Unterdruckes mit den eingangs genannten nachteiligen Folgen auftritt.FIG. 4b shows a known upward closing inlet system shown. Here the negative pressure increases increasing level difference strongly (see Figure 5b). This has the consequence that the above the nozzle inlet in the Gutter standing metal column and the associated static Pressure is insufficient to reach the nozzle inlet to compensate for the resulting negative pressure. Furthermore arises under the stopper there is a stall that is available standing cross section reduced. With larger ones This stall can differ in level up to Impact nozzle outlet, so that there is a reinforcement of the negative pressure with the above-mentioned disadvantageous Consequences occurs.

    Die zu den vorstehenden Betrachtungen herangezogenen Druckverläufe sind von der jeweiligen Lage der Meßpunkte abhängig. Die Darstellungen in Figur 5a, b sind als zweidimensionale Darstellungen anzusehen und sagen daher nichts über die Gleichmäßigkeit der Strömung über den Umfang der Einlaufdüse aus. Wie eingangs dargestellt, können aber bei üblichen Einlaufsystemen Ungleichmäßig keiten über den Umfang der Zulaufdüse auftreten, wodurch Geschwindigkeitsspitzen entstehen, die wiederum den Unterdruck erhöhen.The ones used for the above considerations Pressure curves depend on the position of the measuring points dependent. The representations in Figure 5a, b are as look at two-dimensional representations and therefore say nothing about the uniformity of the flow over the Circumference of the inlet nozzle. As shown at the beginning, but can be uneven with conventional infeed systems keiten occur over the circumference of the inlet nozzle, whereby Speed peaks arise, which in turn create the negative pressure increase.

    Hinzu kommt, daß in der Praxis häufig schief stehende oder krumme Stopfen die Strömungsverhältnisse noch weiter beeinflussen, in der Weise, daß die Inhomogenitäten vergrößert werden. Bei den bekannten Systemen kommt es vor, daß nur eine Häfte des Düsenumfanges durchströmt wird. Somit ergeben sich auch Probleme bei der Regulierung des Volumenstroms, die sich insbesondere bei einer automatischen Niveauregelung nachteilig bemerkbar machen.In addition, in practice, crooked or curved plugs further influence the flow conditions, in such a way that the inhomogeneities are increased become. In the known systems it happens that only half of the nozzle circumference is flowed through. This also creates problems in regulating the Volume flow, which is particularly the case with an automatic Make level control disadvantageously noticeable.

    Bei der erfindungsgemäßen Veränderung der Querschnitte kann der Volumenstrom sehr viel genauer dosiert und das Auftreten von Instabilitäten vermieden werden. Es zeigte sich am Glasmodell, daß eine optimierte Düse auch über den Umfang relativ gleichmäßig durchströmt wird.When changing the cross sections according to the invention the volume flow can be dosed much more precisely and that Avoid occurrence of instabilities. It showed the glass model that an optimized nozzle also over the Flow is relatively even.

    Im Gegensatz dazu neigt das bekannte Einlaufsystem zur Turbulenzbildung. Dies ist anhand der Figur 7 dargestellt und wird im folgenden näher erläutert. Die Schmelze 4 gelangt in Pfeilrichtung durch die Rinne 1 zur Zulaufdüse 2. Durch die an Düsenein- und austritt entstehenden Unterdrucke wird die Schmelzeoberfläche vom Luftdruck eingedellt, wodurch die Oxydschicht aufreißen kann und Oxyd- oder Schmutzteilchen in die Schmelze gesogen werden können. Die nicht verformbaren Verunreinigungen werden in die Erstarrungsfront eingebaut. Beim Späteren Walzprozeß gelangen sie an die Oberfläche und führen zum Aufreißen des Walzbandes oder zu Beschädigungen der Walzen.In contrast, the known inlet system tends to Turbulence formation. This is shown in FIG. 7 and is explained in more detail below. The melt 4 reaches the inlet nozzle in the direction of the arrow through the channel 1 2. The resulting at the nozzle inlet and outlet The melt surface becomes underpressure from the air pressure dented, which can tear open the oxide layer and Oxide or dirt particles are sucked into the melt can. The non-deformable impurities are in the solidification front installed. In the later rolling process they come to the surface and lead to tearing open of the rolled strip or damage to the rolls.

    In Figur 8 ist eine mechanische Regelung des Kokillengießsystems für Aluminiumwalzbarren schematisch dargestellt. Über einen Schwimmer 14, der auf der Metalloberfläche des Barrens positioniert ist, wird über eine mechanische Umlenkung 15 der Stopfen 3 mittels einer Druckstange 16 nach oben oder unten bewegt. Der Begriff "Schwimmer" steht dabei für ein Stück Feuerfestmaterial, das auf der Metalloberfläche schwimmt und über einen Hebel den Metallstand meldet. Im vorliegenden Fall wird damit der Ringspalt zwischen Düse und Stopfen vergrößert oder verkleinert, je nachdem in welche Richtung das Schmelzeniveau vom Sollwert abweicht. Die Zulaufmenge der Metallschmelze wird somit durch unterschiedliche Stopfenhöhen geregelt.In Figure 8 is a mechanical control of the mold casting system shown schematically for aluminum ingots. Via a float 14, which on the metal surface of the Barrens is positioned using a mechanical redirector 15 of the stopper 3 by means of a push rod 16 moved up or down. The term "swimmer" is used for a piece of refractory material that is on the metal surface floats and the metal stand via a lever reports. In the present case, it becomes the annular gap between nozzle and stopper enlarged or reduced, each after which direction the melt level from the set point deviates. The feed rate of the molten metal is thus regulated by different plug heights.

    Andere Methoden bestehen in der Laserabtastung des Metallstandes in der Kokille. Das entstehende Signal wird hier auf elektronischem Wege verarbeitet und zu einer Stellgröße für den Stopfen 3 umgebildet (siehe Figur 6). Other methods consist in laser scanning of the metal stand in the mold. The resulting signal is here processed electronically and to a manipulated variable reshaped for the plug 3 (see Figure 6).

    Der Metallstand in der Kokille 5 kann aus verschiedenen Gründen schwanken. Beispielsweise erfolgt die Neigung des Schmelzeofens nicht kontinuierlich, sodaß eine Schwallbildung in der Rinne 1 auftritt. Auch der Metallstand in der Rinne wird üblicherweise mit einem Schwimmer geregelt, sodaß im Normalfall zwei Regelsysteme miteinander gekoppelt sind. Dies führt zu einem dynamischen Regelverhalten, das während der Gießphase einer ständigen Korrektur der jeweiligen Stopfenhöhe bedarf.The metal level in the mold 5 can be different Reasons fluctuate. For example, the inclination of the Melting furnace not continuously, so that gushing occurs in the channel 1. Even the metal stand in the gutter is usually regulated with a float, so that normally two control systems are coupled together are. This leads to a dynamic control behavior, that during the pouring phase of a constant correction of the each plug height required.

    Schwankungen des Metallstands verändern die thermischen Bedingungen, was zu einer ungünstigen Ausbildung der Barrenoberfläche führt. Die Dicke der Randschale, die vor dem Walzen vollständig abgefräst werden muß, vergrößert sich.Fluctuations in the metal level change the thermal Conditions, leading to unfavorable training of the Ingot surface leads. The thickness of the rim shell that before the rolling must be completely milled, enlarged yourself.

    Claims (7)

    1. A supplying system for continuous aluminium casting plants, consisting of a launder, an inlet nozzle (2) which is inserted into the launder (1) and into which there is inserted a plug (3) for regulating the melt inlet (4), with the plug (3) closing the melt inlet at the narrowest cross-section of the inlet nozzle (2), and furthermore consisting of a control system by means of which the immersion depth of the plug is controllable within predetermined limits,
      characterised in
      that from the narrowest cross-section of the nozzle (2) to the nozzle entry (X) and nozzle exit (Y), a distance (A1, A2) of at least 7 cm is observed, and that at the nozzle entry, the space between the nozzle (2) and the plug (3) is narrowed along a length B which ranges from greater 0 to 10 cm.
    2. A suppling system according to claim 1,
      characterised in
      that narrowing takes place along a length of 1 - 10 cm.
    3. A supplying system according to any one of the preceding claims,
      characterised in
      that above the narrowest nozzle cross-section between the nozzle (2) and the plug (3), there is formed an annular space D which becomes narrower in the direction of flow, whereas below the narrowest nozzle cross-section, the space between the nozzle (2) and the plug (3) is widened by an opening angle of at least 4°, with the plug point S being rounded with a radius of 10 - 14 mm.
    4. A supplying system according to any one of the preceding claims,
      characterised in
      that the edges at the entry and exit are rounded with a radius of 5 - 25 mm.
    5. A supplying system according to any one of the preceding claims,
      characterised in
      that the annular space D is formed by an annular gap between the nozzle (2) and the plug (3), with the side walls forming the annular gap extending nearly parallel relative to one another.
    6. A supplying system according to claim 5,
      characterised in
      that the nearly parallel side walls of the annular space D become narrower in the direction of flow with a difference in angles of approximately 1°.
    7. A method of regulating a supplying system for continuous aluminium casting plants according to any one of the preceding claims 1 to 6,
      characterised in
      that there are set a metal level H in the launder (1) of at least 5 cm above the nozzle entry X and an immersion depth T of the nozzle (2) of least 2 cm.
    EP94108061A 1993-07-05 1994-05-26 Supplying system in a continuous aluminium casting system Expired - Lifetime EP0637477B1 (en)

    Applications Claiming Priority (2)

    Application Number Priority Date Filing Date Title
    DE4322316 1993-07-05
    DE4322316A DE4322316C1 (en) 1993-07-05 1993-07-05 Infeed system for an aluminum continuous casting plant

    Publications (3)

    Publication Number Publication Date
    EP0637477A2 EP0637477A2 (en) 1995-02-08
    EP0637477A3 EP0637477A3 (en) 1996-04-03
    EP0637477B1 true EP0637477B1 (en) 1999-03-24

    Family

    ID=6491984

    Family Applications (1)

    Application Number Title Priority Date Filing Date
    EP94108061A Expired - Lifetime EP0637477B1 (en) 1993-07-05 1994-05-26 Supplying system in a continuous aluminium casting system

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    US (1) US5490554A (en)
    EP (1) EP0637477B1 (en)
    KR (1) KR970005376B1 (en)
    AU (1) AU674749B2 (en)
    BR (1) BR9402624A (en)
    CA (1) CA2127321C (en)
    CZ (1) CZ285017B6 (en)
    DE (2) DE4322316C1 (en)
    ES (1) ES2133443T3 (en)
    HU (1) HU216124B (en)
    NO (1) NO300034B1 (en)
    PL (1) PL177723B1 (en)
    RU (1) RU2091193C1 (en)
    SK (1) SK78394A3 (en)
    TW (1) TW289002B (en)
    YU (1) YU41294A (en)

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    Publication number Priority date Publication date Assignee Title
    DE19504009A1 (en) * 1995-02-08 1996-08-14 Vaw Ver Aluminium Werke Ag Infeed system for an aluminum continuous casting plant
    DE19706151C2 (en) * 1997-02-18 2000-12-07 Sms Demag Ag Process and dip tube for continuous metal casting
    KR100330352B1 (en) * 1999-07-02 2002-04-01 유현식 Syndiotactic Polystyrene Compositions having Improved Impact Strength
    NL1014024C2 (en) * 2000-01-06 2001-07-09 Corus Technology Bv Apparatus and method for continuous or semi-continuous casting of aluminum.
    US7041171B2 (en) * 2003-09-10 2006-05-09 Kastalon, Inc. Nozzle for use in rotational casting apparatus
    US7270711B2 (en) * 2004-06-07 2007-09-18 Kastalon, Inc. Nozzle for use in rotational casting apparatus
    US6989061B2 (en) * 2003-08-22 2006-01-24 Kastalon, Inc. Nozzle for use in rotational casting apparatus
    JP5621737B2 (en) * 2011-09-15 2014-11-12 新日鐵住金株式会社 Flow rate adjustment method in continuous casting
    WO2014164911A1 (en) 2013-03-12 2014-10-09 Novelis Inc. Intermittent molten metal delivery
    JP2018536085A (en) * 2015-09-15 2018-12-06 リテック システムズ エルエルシー Laser sensor for melt control in furnace-type blast furnaces
    CA3049465C (en) 2017-11-15 2021-10-12 Novelis Inc. Metal level overshoot or undershoot mitigation at transition of flow rate demand

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    * Cited by examiner, † Cited by third party
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    GB917565A (en) * 1960-05-13 1963-02-06 Didier Werke Ag Improvements relating to pouring nozzles for liquid metal
    US4523624A (en) * 1981-10-22 1985-06-18 International Telephone And Telegraph Corporation Cast ingot position control process and apparatus
    FR2639267B1 (en) * 1988-11-23 1991-02-22 Clecim Sa PROCESS AND ASSEMBLY FOR SUPPLYING MOLTEN METAL TO THE LINGOTIERE OF A CONTINUOUS CASTING INSTALLATION OF THIN BLANKS
    US5205343A (en) * 1989-06-03 1993-04-27 Sms Schloemann-Siemag Aktiengesellschaft Pouring tube for feeding molten steel into a continuous casting mold
    US5339885A (en) * 1993-05-07 1994-08-23 Wagstaff Inc. Integrated non-contact molten metal level sensor and controller

    Also Published As

    Publication number Publication date
    CZ285017B6 (en) 1999-05-12
    TW289002B (en) 1996-10-21
    HU9401732D0 (en) 1994-09-28
    KR950002888A (en) 1995-02-16
    DE59407993D1 (en) 1999-04-29
    PL303861A1 (en) 1995-01-09
    SK78394A3 (en) 1995-09-13
    CZ160694A3 (en) 1997-05-14
    HUT67850A (en) 1995-05-29
    RU94024564A (en) 1996-04-20
    EP0637477A2 (en) 1995-02-08
    AU674749B2 (en) 1997-01-09
    HU216124B (en) 1999-04-28
    KR970005376B1 (en) 1997-04-15
    CA2127321A1 (en) 1995-01-06
    DE4322316C1 (en) 1995-03-16
    CA2127321C (en) 1999-05-11
    US5490554A (en) 1996-02-13
    BR9402624A (en) 1995-04-04
    NO300034B1 (en) 1997-03-24
    AU6613294A (en) 1995-01-12
    RU2091193C1 (en) 1997-09-27
    NO941868D0 (en) 1994-05-19
    NO941868L (en) 1995-01-06
    PL177723B1 (en) 2000-01-31
    ES2133443T3 (en) 1999-09-16
    YU41294A (en) 1996-10-09
    EP0637477A3 (en) 1996-04-03

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