EP0049238A2 - Method of controlling the discharge of billets - Google Patents

Method of controlling the discharge of billets Download PDF

Info

Publication number
EP0049238A2
EP0049238A2 EP81890155A EP81890155A EP0049238A2 EP 0049238 A2 EP0049238 A2 EP 0049238A2 EP 81890155 A EP81890155 A EP 81890155A EP 81890155 A EP81890155 A EP 81890155A EP 0049238 A2 EP0049238 A2 EP 0049238A2
Authority
EP
European Patent Office
Prior art keywords
strand
mold
skin
contraction
casting
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
EP81890155A
Other languages
German (de)
French (fr)
Other versions
EP0049238B1 (en
EP0049238A3 (en
Inventor
Max Ahrens
Manfred Dipl.-Ing Haissig
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.)
Boehler AG
Original Assignee
Boehler AG
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 Boehler AG filed Critical Boehler AG
Priority to AT81890155T priority Critical patent/ATE9656T1/en
Publication of EP0049238A2 publication Critical patent/EP0049238A2/en
Publication of EP0049238A3 publication Critical patent/EP0049238A3/en
Application granted granted Critical
Publication of EP0049238B1 publication Critical patent/EP0049238B1/en
Expired legal-status Critical Current

Links

Images

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
    • B22D11/16—Controlling or regulating processes or operations
    • B22D11/20—Controlling or regulating processes or operations for removing cast stock

Definitions

  • the invention relates to a method for controlling the strand withdrawal from a horizontal continuous casting mold cooled with a cooling medium with a material of higher thermal conductivity, the strand being withdrawn step by step from the mold and the metal melt, e.g. Steel melt, discontinuously enters the mold and, after forming a strand skin, the strand is pulled off again by one step and then pushed back by a partial step.
  • the metal melt e.g. Steel melt
  • the strand that is formed is gradually withdrawn from metals that have a higher melting point from a stationary or movable horizontal mold. There is either a downtime between the individual steps or the strand is pushed back by a partial step. This procedure is followed in order to bring about a welding of the strand skin which forms directly from the melt with the strand skin which has already been formed and has already been removed by one step. If no complete welding has taken place, there is a risk that the strand skin remains at the beginning of the mold and that there is liquid melt between it and the strand skin that has been pulled off with the strand, which has already been partially solidified, which can escape from the mold when the strand is withdrawn further.
  • a control of the strand withdrawal can be carried out as a function of the strand skin formation, but the delays between non-welding of the strand skin sections and the measurement of the temperature drop are so great that a breakthrough of the melt from the mold cannot be prevented with certainty.
  • a disadvantage of this method is that the temperature is measured on the wall of the mold, but this is dependent on the amount of heat reaching the measuring point. The amount of heat does not get through Heat radiation, but through heat conduction, which takes a considerable amount of time, to the measuring point.
  • the invention has for its object to provide a method for controlling the strand withdrawal, in which the above. Disadvantages are avoided and it is easy to carry out.
  • the process according to the invention essentially consists in that the strand withdrawal is controlled as a function of the expansion or contraction of the mold wall in contact with the strand skin.
  • the stretching or contraction is caused by forces. In contrast to heat, these forces propagate immediately into an area where they can be measured, etc. at a point in time at which no temperature change has yet occurred at the measuring location.
  • the strand withdrawal is controlled as a function of the expansion or contraction of the mold wall which alternately contacts the molten metal or the skin of the strand.
  • the measurement of the expansion or contraction can be carried out particularly advantageously in the space through which the cooling medium flows, since the measurement there can be carried out particularly simply at an approximately constant temperature.
  • FIG. 1 shows a schematic illustration of a horizontal continuous casting installation in section
  • FIG. 2 shows two diagrams
  • FIG. 3 shows a block diagram.
  • 1 means the melt container, which has a channel 2. Between this and the mold 3, a two-part nozzle block 4 and 5 is arranged, through which the melt reaches the mold from the melt container.
  • the nozzle block 5 extends with its cylindrical extension into the channel 2, whereas the nozzle block 4 has a conical lumen which opens into the mold cavity.
  • the mold is detachably connected to the melt vessel by screws (not shown). It has a jacket 6 through which the cooling water flows, the inlet and outlet taking place through the pipe sockets 7 and 8.
  • a take-off roller 9 is provided, which is driven by a motor, not shown. The strand 10 is pressed against the take-off roller 9 by the pivotably mounted roller 11 and the compression spring 12.
  • the strand has an outer, already solidified strand skin, within which liquid melt is still present.
  • the strand skin is formed immediately after the nozzle block 4, the liquid melt reaching the mold wall in each case in a withdrawal step, thus heating and expanding it.
  • a strand skin ring is formed, which has a taper.
  • a strain gauge 13 is arranged in the jacket 6 through which the cooling water flows, on the wall forming the strand skin. This strain gauge is arranged in the transverse direction of the strand. This arrangement is particularly advantageous for small strands to be formed and small step lengths.
  • the strain gauge is soldered or welded to the surface of the wall and coated with an epoxy resin. It has an external power line (not shown).
  • the strand is pushed back by a partial step, which is approximately 10% of the forward-facing step, which on the one hand compensates for the lengthwise shrinkage of the strand, which is caused by the cooling thereof, and furthermore a collision of the strand skin is reached. If there is no welding of the strand skin sections, a strand skin section remains in the area of the first solidification, whereas the further strand skin sections are pulled off with the strand, as a result of which the liquid melt also reaches the mold wall outside of the area in which the strand skin is usually formed.
  • FIGS. 2a and 2b The typical time and voltage profiles are given in FIGS. 2a and 2b.
  • the diagram of FIG. 2a relates to a measurement result which is obtained when the strain gauge or the pressure-sensitive quartz crystal is arranged in an area in which no melt comes to the inner wall in the case of trouble-free continuous casting. Such a trouble-free course is given in the area x 1 .
  • the step lasts in each case one second, with a slight change in the elongation taking place in accordance with the tapering in the respective strand skin sections, as is represented in the area x 1 by the respective maxima.
  • the area Xz is significant for a beginning strand break, in which the liquid melt reaches the inside wall of the mold and thus causes a greater expansion of the same.
  • the entire strand is pushed back until the strand skin section which has remained in the mold has been welded to the rest of the strand skin, which can usually be achieved with less than one step back. This pushing back is shown in section x3. After the strand skin sections have been welded together, the usual strand withdrawal takes place again.
  • the stress states on the outer mold wall are shown by specifying the change in length in the area of the strand skin formation.
  • the section x l relates to a trouble-free strand withdrawal, with the melt reaching the mold wall when the newly formed strand skin section is withdrawn, which causes a tension on the outer wall, which is steadily reduced by the simultaneous cooling.
  • the strand is then moved back by approximately i 0 of the step, so that the change in voltage through the arbitrarily determined zero point reaches the negative range.
  • the strand is drawn off again immediately, whereupon liquid melt reaches the mold inner wall again.
  • the strain or tension measuring strip can be arranged in any region, since a break in the strand represents a particularly significant event, by means of which the normal course of the change in tension is changed.
  • 14 means the mold wall, which is surrounded by the jacket 6, with the cooling water flowing through the intermediate space.
  • two strain gauges 13 are arranged, one of which measures the tension or elongation in the longitudinal direction and the other in the transverse direction to the strand.
  • the strain gauges are connected to a current source via resistors R1 and R2.
  • the flowing current is in the amplifier V amplified and shown in oscillograph 0.
  • the oscillograph has a further input for the control pulses of the drive control A.
  • the pulses from the amplifier also go to a wave analyzer W, in which an acoustic signal generator S is actuated when a threshold value is exceeded or undershot, and a signal is also output to the drive control, as a result of which the pull-off motor M pushes the string back by less than one step length.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)
  • Forging (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
  • Measurement Of Radiation (AREA)
  • Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
  • Pinball Game Machines (AREA)

Abstract

A process for controllng the withdrawal of a casting from a cooled, horizontal, continuous casting mold involves withdrawing the casting from the mold in a series of steps, between which steps the casting is pushed back by a partial step to insure the welding together of casting sections. A melt breakthrough of the casting skin is prevented by measuring the expansion or contraction of a wall of the mold in contact with the casting and controlling the withdrawal of the casting in response thereto.

Description

Die Erfindung bezieht sich auf ein Verfahren zur Steuerung des Strangabzuges aus einer mit einem Kühlmedium gekühlten horizontalen Stranggußkokille mit einem Material höherer Wärmeleitfähigkeit, wobei der Strang schrittweise aus der Kokille abgezogen wird und die Metallschmelze, z.B. Stahlschmelze, diskontinuierlich in die Kokille gelangt und nach Bildung einer Stranghaut der Strang erneut um einen Schritt abgezogen und sodann um einen Teilschritt zurückgeschoben wird.The invention relates to a method for controlling the strand withdrawal from a horizontal continuous casting mold cooled with a cooling medium with a material of higher thermal conductivity, the strand being withdrawn step by step from the mold and the metal melt, e.g. Steel melt, discontinuously enters the mold and, after forming a strand skin, the strand is pulled off again by one step and then pushed back by a partial step.

Bei dem Horizontal-Strangguß wird aus einer feststehenden oder beweglichen horizontalen Kokille der sich bildende Strang bei höher schmelzenden Metallen schrittweise abgezogen. Zwischen den einzelnen Schritten wird entweder eine Stillstandszeit eingehalten oder der Strang um einen Teilschritt zurückgeschoben. Diese Vorgangsweise wird eingehalten, um ein Verschweißen der sich unmittelbar aus der Schmelze bildenden Stranghaut mit der bereits gebildeten und bereits einen Schritt abgezogenen Stranghaut zu bewirken. Wenn keine vollständige Verschweißung stattgefunden hat, so besteht die Gefahr, daß die Stranghaut am Beginn -der Kokille verbleibt und zwischen dieser und der mit dem bereits teilweise verfestigten Strang abgezogenen Stranghaut flüssige Schmelze vorhanden ist, welche bei einem weiteren Strangabzug aus der Kokille austreten kann. Tritt ein sogenannter Durchbruch des Stranges wie oben beschrieben auf, so muß der Strangguß abgebrochen werden. Neben der erhöhten Unfallsgefahr tritt eine erhebliche Produktionsunterbrechung auf. Zur Vermeidung eines derartigen Strangdurchbruches ist bereits ein Verfahren zum Stranggießen bekannt geworden, bei dem die Temperatur punktförmig an der Kokillenwandung unmittelbar beim Schmelzeneintritt in die Kokille gemessen wird. Fällt die Temperatur um 8° - 25° C unter eine vorbestimmte Temperatur, so wird der Strang solange stillgehalten, bis erneut ein Temperaturanstieg gemessen werden kann. Mit diesem Verfahren kann zwar eine Steuerung des Strangabzuges in Abhängigkeit von der Stranghautbildung durchgeführt werden, jedoch sind die Verzögerungen zwischen Nichtverschweißen der Stranghautabschnitte und dem Messen des Temperaturabfalles so groß, daß trotzdem ein Durchbruch der Schmelze aus der Kokille nicht mit Sicherheit verhindert werden kann. Nachteilig bei diesem Verfahren ist, daß die Temperatur an der Wand der Kokille gemessen wird und diese jedoch in Abhängigkeit von der zum Meßpunkt gelangenden Wärmemenge steht. Die Wärmemenge gelangt nicht durch Wärmestrahlung, sondern durch Wärmeleitung, welche eine erhebliche Zeit in Anspruch nimmt, zum Meßpunkt.In the case of horizontal continuous casting, the strand that is formed is gradually withdrawn from metals that have a higher melting point from a stationary or movable horizontal mold. There is either a downtime between the individual steps or the strand is pushed back by a partial step. This procedure is followed in order to bring about a welding of the strand skin which forms directly from the melt with the strand skin which has already been formed and has already been removed by one step. If no complete welding has taken place, there is a risk that the strand skin remains at the beginning of the mold and that there is liquid melt between it and the strand skin that has been pulled off with the strand, which has already been partially solidified, which can escape from the mold when the strand is withdrawn further. If a so-called breakthrough of the strand occurs as described above, the continuous casting must be stopped. In addition to the increased risk of accidents, there is a significant interruption in production. In order to avoid such a strand breakthrough, a method for continuous casting has already become known in which the temperature is measured in a punctiform manner on the mold wall directly when the melt enters the mold. If the temperature falls by 8 ° - 25 ° C below a predetermined temperature, the strand is kept still until a temperature rise can be measured again. With this method, a control of the strand withdrawal can be carried out as a function of the strand skin formation, but the delays between non-welding of the strand skin sections and the measurement of the temperature drop are so great that a breakthrough of the melt from the mold cannot be prevented with certainty. A disadvantage of this method is that the temperature is measured on the wall of the mold, but this is dependent on the amount of heat reaching the measuring point. The amount of heat does not get through Heat radiation, but through heat conduction, which takes a considerable amount of time, to the measuring point.

Ein weiteres Verfahren zum schrittweisen Abziehen des Stranges aus einer horizontalen Stranggießkokille wird aus der DE-PS 23 40 636 bekannt, wobei der Strangabzug bzw. die Strangstillstandszeiten über das Motordrehmoment gesteuert werden. Bei dieser Steuerung wird davon ausgegangen, daß bei ungenügender Abkühlung der Stranghaut diese noch an der Kokillenwandung anliegt und daher einen größeren Widerstand beim Abziehen bewirkt. Nachteilig bei diesem Verfahren ist, daß bei einem Nichtverschweißen der frisch gebildeten Stranghaut mit der abzuziehenden Stranghaut kein größerer Widerstand, sondern nur ein nennenswert kleinerer Widerstand dem Abzug entgegensteht, sodaß auch hier die Gefahr besteht, daß die Schmelze aus der Kokille austreten kann.Another method for gradually withdrawing the strand from a horizontal continuous casting mold is known from DE-PS 23 40 636, the strand withdrawal or the strand standstill times being controlled via the engine torque. With this control it is assumed that if the strand skin cools insufficiently, it will still rest against the mold wall and therefore cause greater resistance when pulling off. The disadvantage of this method is that if the newly formed strand skin is not welded to the strand skin to be drawn off, there is no greater resistance, but only a noticeably smaller resistance, so that there is also a risk that the melt can escape from the mold.

Die Erfindung hat sich zur Aufgabe gestellt, ein Verfahren zur Steuerung des Strangabzuges zu schaffen, bei dem die o.a. Nachteile vermieden werden und das einfach in der Durchführung ist.The invention has for its object to provide a method for controlling the strand withdrawal, in which the above. Disadvantages are avoided and it is easy to carry out.

Das erfindungsgemäße Verfahren besteht im wesentlichen darin, daß der Strangabzug in Abhängigkeit von der Dehnung bzw. Kontraktion der mit der Stranghaut in Kontakt stehenden Kokillenwandung gesteuert wird. Die Dehnung bzw. Kontraktion wird durch Kräfte bewirkt. Diese Kräfte pflanzen sich zum Unterschied von Wärme sofort in einen Bereich fort, wo sie meßtechnisch erfaßt werden können, u.zw. zu einem Zeitpunkt, zu dem am Meßort noch keine Temperaturänderung eingetreten ist.The process according to the invention essentially consists in that the strand withdrawal is controlled as a function of the expansion or contraction of the mold wall in contact with the strand skin. The stretching or contraction is caused by forces. In contrast to heat, these forces propagate immediately into an area where they can be measured, etc. at a point in time at which no temperature change has yet occurred at the measuring location.

Um eine möglichst frühzeitige Registrierung des Strangdurchbruches zu ermöglichen, wird der Strangabzug in Abhängigkeit von der Dehnung bzw. Kontraktion der mit der Metallschmelze bzw. Stranghaut alternierend in Kontakt stehenden Kokillenwandung gesteuert.In order to enable the strand breakthrough to be registered as early as possible, the strand withdrawal is controlled as a function of the expansion or contraction of the mold wall which alternately contacts the molten metal or the skin of the strand.

Besonders vorteilhaft kann die Messung der Dehnung bzw. Kontraktion im vom Kühlmedium durchflossenen Raum durchgeführt werden, da dort die Messung besonders einfach bei annähernd konstanter Temperatur durchgeführt werden kann.The measurement of the expansion or contraction can be carried out particularly advantageously in the space through which the cooling medium flows, since the measurement there can be carried out particularly simply at an approximately constant temperature.

Es hat sich als vorteilhaft erwiesen, bei einer bleibenden Kontraktion bzw. Dehnung der Kokilleninnenwandung, d.h., daß die Kontraktion nicht mehr von der Dehnung in einem vorgegebenen Intervall abgelöst wird und umgekehrt, den Strang weniger als um eine Schrittlänge zurückzuschieben. Dadurch kann ein sicheres Verschweißen der in der Kokille stehengebliebenen Stranghaut mit jener des abgezogenen Stranges bewirkt werden, wobei eine Beschädigung der Düsensteine vermieden wird.In the case of a permanent contraction or stretching of the inner wall of the mold, i.e. that the contraction is no longer separated from the stretching in a predetermined interval and vice versa, it has proven to be advantageous to push the strand back less than by one step length. As a result, the strand skin remaining in the mold can be securely welded to that of the drawn-off strand, damage to the nozzle stones being avoided.

Im folgenden wird das erfindungsgemäße Verfahren an Hand der Zeichnung näher erläutert:

  • Es zeigen Fig. 1 eine Stranggußkokille mit einem Dehnungsmeßstreifen und Fig. 2 ein Diagramm in welchem die Dehnung bzw. Kontraktion im zeitlichen Verlauf dargestellt ist.
The method according to the invention is explained in more detail below with reference to the drawing:
  • 1 shows a continuous casting mold with a strain gauge and FIG. 2 shows a diagram in which the expansion or contraction is shown over time.

Es zeigen Fig. 1 in schematischer Darstellung eine horizontale Stranggußanlage im Schnitt, Fig. 2 zwei Diagramme und Fig. 3 ein Blockschema.1 shows a schematic illustration of a horizontal continuous casting installation in section, FIG. 2 shows two diagrams and FIG. 3 shows a block diagram.

Bei der in Fig. 1 dargestellten horizontalen Stranggußanlage bedeutet 1 der Schmelzenbehälter, welcher einen Kanal 2 aufweist. Zwischen diesem und der Kokille 3 ist ein zweiteiliger Düsenstein 4 und 5 angeordnet, durch welchen die Schmelze vom Schmelzenbehälter in die Kokille gelangt. Der Düsenstein 5 reicht mit seinem zylindrischen Fortsatz in den Kanal2, wohingegen der Düsenstein 4 ein kegelförmiges Lumen aufweist, das in den Kokillenhohlraum mündet. Die Kokille ist über Schrauben (nicht dargestellt) mit dem Schmelzengefäß lösbar verbunden. Sie weist einen vom Kühlwasser durchflossenen Mantel 6 auf, wobei der Zu- bzw. Ablauf durch die Rohrstutzen 7 und 8 erfolgt. Weiters ist eine Abzugsrolle 9 vorgesehen, die von einem nichtdargestellten Motor angetrieben wird. Der Strang 10 wird durch die schwenkbar gelagerte Rolle 11 und die Druckfeder 12 gegen die Abzugsrolle 9 gepreßt. Der Strang weist, wie strichliert dargestellt, eine äußere, bereits verfestigte Stranghaut auf, innerhalb welcher noch flüssige Schmelze vorhanden ist. Die Stranghaut wird unmittelbar nach dem Düsenstein 4 gebildet, wobei jeweils bei einem Abzugsschritt die flüssige Schmelze an die Kokillenwandung gelangt, diese somit erwärmt und ausdehnt. Während eines Schrittes wird jeweils ein Stranghautring gebildet, welcher eine Verjüngung aufweist. In diesem Bereich ist im vom Kühlwasser durchflossenen Mantel 6 an der die Stranghaut formenden Wandung ein Dehnungsmeßstreifen 13 angeordnet. Dieser Dehnungsmeßstreifen ist in Strangquerrichtung angeordnet. Diese Anordnung ist insbesondere für kleine zu formende Stränge und kleine Schrittlängen von Vorteil. Der Dehnungsmeßstreifen ist auf der Oberfläche der Wandung angelötet bzw. angeschweißt und mit einem Epoxiharz umhüllt. Er weist eine nach außen führende Stromleitung (nicht dargestellt) auf. Am Ende eines nach vorwärts gerichteten Abzugschrittes wird der Strang um einen Teilschritt, der etwa 10 % des nach vorwärts gerichteten Schrittes beträgt, zurückgeschoben, wodurch einerseits die Längenschrumpfung des Stranges, welche durch das Abkühlen desselben verursacht wird, ausgeglichen wird und weiters ein Zusammenstoßen der Stranghaut erreicht ist. Tritt kein Verschweißen der Stranghautabschnitte ein, so verbleibt ein Stranghautabschnitt im Bereich der ersten Verfestigung, wohingegen die weiteren Stranghautabschnitte mit dem Strang abgezogen werden, wodurch die flüssige Schmelze auch außerhalb jenes Bereiches an die Kokillenwandung gelangt, in welchem üblicherweise die Stranghaut gebildet wird. Es wird somit, wenn in diesem weiteren Bereich, wo üblicherweise keine Schmelze an die Wandung gelangt, die Wandung durch die Wärmedehnung stärker gedehnt als üblich, sodaß dort Spannungen gemessen werden können, die üblicherweise nicht vorhanden sind. Im Bereich, in dem die Stranghaut gebildet wird, erfolgt jedoch eine weitere Kühlung des Stranghautabschnittes, sodaß eine weitere Kontraktion der inneren Kokillenwandung bewirkt wird, wodurch eine Reduktion der Spannung eintritt.In the horizontal continuous casting installation shown in FIG. 1, 1 means the melt container, which has a channel 2. Between this and the mold 3, a two-part nozzle block 4 and 5 is arranged, through which the melt reaches the mold from the melt container. The nozzle block 5 extends with its cylindrical extension into the channel 2, whereas the nozzle block 4 has a conical lumen which opens into the mold cavity. The mold is detachably connected to the melt vessel by screws (not shown). It has a jacket 6 through which the cooling water flows, the inlet and outlet taking place through the pipe sockets 7 and 8. Furthermore, a take-off roller 9 is provided, which is driven by a motor, not shown. The strand 10 is pressed against the take-off roller 9 by the pivotably mounted roller 11 and the compression spring 12. As shown in dashed lines, the strand has an outer, already solidified strand skin, within which liquid melt is still present. The strand skin is formed immediately after the nozzle block 4, the liquid melt reaching the mold wall in each case in a withdrawal step, thus heating and expanding it. During each step, a strand skin ring is formed, which has a taper. In this area a strain gauge 13 is arranged in the jacket 6 through which the cooling water flows, on the wall forming the strand skin. This strain gauge is arranged in the transverse direction of the strand. This arrangement is particularly advantageous for small strands to be formed and small step lengths. The strain gauge is soldered or welded to the surface of the wall and coated with an epoxy resin. It has an external power line (not shown). At the end of a forward-pulling step, the strand is pushed back by a partial step, which is approximately 10% of the forward-facing step, which on the one hand compensates for the lengthwise shrinkage of the strand, which is caused by the cooling thereof, and furthermore a collision of the strand skin is reached. If there is no welding of the strand skin sections, a strand skin section remains in the area of the first solidification, whereas the further strand skin sections are pulled off with the strand, as a result of which the liquid melt also reaches the mold wall outside of the area in which the strand skin is usually formed. It is thus, when in this further area, where usually no melt reaches the wall, the wall is stretched more than usual due to the thermal expansion, so that stresses that are usually not present can be measured there. In the area in which the strand skin is formed, however, the strand skin section is cooled further, so that a further contraction of the inner mold wall is brought about, which leads to a reduction in tension.

In Fig. 2a bzw. 2b sind die typischen Zeit- und Spannungsverläufe angegeben. Zur besseren Vorstellung ist an Stelle der Spannung die Längenänderung, u.zw. an der Außenseite der Kokillenwandung gezeigt. Das Diagramm der Fig. 2a bezieht sich auf ein Meßergebnis, das erhalten wird, wenn der Dehnungsmeßstreifen bzw. der druckempfindliche Quarzkristall in einem Bereich angeordnet ist, in dem bei einem störungsfreien Strangguß keine Schmelze an die Innenwandung kommt. Ein derartiger störungsfreier Verlauf ist im Bereich xl angegeben. Der Schritt dauert jeweils eine Sekunde, wobei entsprechend der eingetretenen Verjüngung in den jeweiligen Stranghautabschnitten jeweils eine geringfügige Änderung der Dehnung erfolgt, wie sie im Bereich xl durch die jeweiligen Maxima dargestellt ist. Der Bereich Xz ist für einen beginnenden Strangdurchbruch signifikant, bei welchem die flüssige Schmelze an die Innenwandung der Kokille gelangt und so eine größere Dehnung derselben bewirkt. Ausgelöst von der unmittelbaren Dehnungsanzeige wird der gesamte Strang zurückgeschoben, bis ein Verschweißen des in der Kokille stehengebliebenen Stranghautabschnittes mit der restlichen Stranghaut erfolgt ist, welches mit weniger als einem Schritt zurück in der Regel erreicht werden kann. Dieses Zurückschieben ist im Abschnitt x3 dargestellt. Nach dem Verschweißen der Stranghautabschnitte erfolgt wieder der übliche Strangabzug.The typical time and voltage profiles are given in FIGS. 2a and 2b. For a better idea, instead of the tension, the change in length, etc. shown on the outside of the mold wall. The diagram of FIG. 2a relates to a measurement result which is obtained when the strain gauge or the pressure-sensitive quartz crystal is arranged in an area in which no melt comes to the inner wall in the case of trouble-free continuous casting. Such a trouble-free course is given in the area x 1 . The step lasts in each case one second, with a slight change in the elongation taking place in accordance with the tapering in the respective strand skin sections, as is represented in the area x 1 by the respective maxima. The area Xz is significant for a beginning strand break, in which the liquid melt reaches the inside wall of the mold and thus causes a greater expansion of the same. Triggered by the immediate stretch indicator, the entire strand is pushed back until the strand skin section which has remained in the mold has been welded to the rest of the strand skin, which can usually be achieved with less than one step back. This pushing back is shown in section x3. After the strand skin sections have been welded together, the usual strand withdrawal takes place again.

Bei dem in Fig. 2b dargestellten Diagramm sind die Spannungszustände an der Kokillenaußenwandung durch Angabe der Längenänderung im Bereich der Stranghautbildung dargestellt. Der Abschnitt xl bezieht sich auf einen störungsfreien Strangabzug, wobei bei Abzug des neu gebildeten Stranghautabschnittes Schmelze an die Kokillenwandung gelangt, wodurch eine Spannung an der Außenwandung bedingt ist, welche durch die gleichzeitige Abkühlung stetig abgebaut wird. Sodann wird der Strang um ca. i0 des Schrittes zurückbewegt, sodaß die Spannungsänderung durch den willkürlich festgelegten Nullpunkt in den negativen Bereich gelangt. Es wird der Strang sofort wieder abgezogen, worauf flüssige Schmelze erneut zur Kokilleninnenwandung gelangt. Bleibt der neu gebildete Stranghautabschnitt jedoch in der Kokille stehen und wird nicht gemeinsam mit dem übrigen Strang abgezogen, so erfolgt, wie im Abschnitt 2 dargestellt, ein weiterer Abbau der Spannungen, d.h. Kontraktion der Kokillenwandung, welche erst mit Einleiten des Zurückschiebens, das im Abschnitt x3 dargestellt ist, zum früheren, bereits im Bereich xl dargestellten Spannungsverlauf, führt.In the diagram shown in FIG. 2b, the stress states on the outer mold wall are shown by specifying the change in length in the area of the strand skin formation. The section x l relates to a trouble-free strand withdrawal, with the melt reaching the mold wall when the newly formed strand skin section is withdrawn, which causes a tension on the outer wall, which is steadily reduced by the simultaneous cooling. The strand is then moved back by approximately i 0 of the step, so that the change in voltage through the arbitrarily determined zero point reaches the negative range. The strand is drawn off again immediately, whereupon liquid melt reaches the mold inner wall again. If, however, the newly formed strand skin section remains in the mold and is not pulled off together with the rest of the strand, then, as shown in section 2, the stresses are further reduced, i.e. contraction of the mold wall, which only takes place when the pushing back is initiated in the section x 3 is shown, leads to the earlier voltage curve already shown in area x l .

Der Dehnungs- bzw. Spannungsmeßstreifen kann, wie aus den Ausführungen ersichtlich, in jedem beliebigen Bereich angeordnet werden, da ein Durchbruch des Stranges ein besonders signifikantes Ereignis darstellt, durch welches der normale Spannungsänderungsverlauf geändert wird.As can be seen from the explanations, the strain or tension measuring strip can be arranged in any region, since a break in the strand represents a particularly significant event, by means of which the normal course of the change in tension is changed.

In Fig. 3 bedeutet 14 die formende Kokillenwandung, welche vom Mantel 6 umgeben ist, wobei der Zwischenraum vom Kühlwasser durchflossen ist. Auf dieser Wandung 14 sind zwei Dehnungsmeßstreifen 13 angeordnet, von welchen einer die Spannung bzw. Dehnung in Längs- und der weitere in Querrichtung zum Strang mißt. Die Dehnungsmeßstreifen sind mit einer Stromquelle über Widerstände Rl und R2 verbunden. Der fließende Strom wird im Verstärker V verstärkt und im Oszillographen 0 dargestellt. Der Oszillograph weist einen weiteren Eingang für die Steuerimpulse der Antriebssteuerung A auf. Die Impulse aus dem Verstärker gehen weiters zu einem Wellenanalysator W, in welchem bei Überschreiten bzw. Unterschreiten eines Schwellenwertes ein akustischer Signalgeber S betätigt wird und weiters an die Antriebssteuerung ein Signal abgegeben wird, wodurch der Abzugsmotor M den Strang um weniger als eine Schrittlänge zurückschiebt.In Fig. 3, 14 means the mold wall, which is surrounded by the jacket 6, with the cooling water flowing through the intermediate space. On this wall 14 two strain gauges 13 are arranged, one of which measures the tension or elongation in the longitudinal direction and the other in the transverse direction to the strand. The strain gauges are connected to a current source via resistors R1 and R2. The flowing current is in the amplifier V amplified and shown in oscillograph 0. The oscillograph has a further input for the control pulses of the drive control A. The pulses from the amplifier also go to a wave analyzer W, in which an acoustic signal generator S is actuated when a threshold value is exceeded or undershot, and a signal is also output to the drive control, as a result of which the pull-off motor M pushes the string back by less than one step length.

Claims (4)

1. Verfahren zur Steuerung des Strangabzuges aus einer mit einem Kühlmedium gekühlten horizontalen Stranggußkokille mit einem Material höherer Wärmeleitfähigkeit, wobei der Strang schrittweise aus der Kokille abgezogen wird und die Metallschmelze, vorzugsweise Stahlschmelze, diskontinuierlich in die Kokille gelangt und nach Bildung einer Stranghaut der Strang erneut um einen Schritt abgezogen und sodann um einen Teilschritt zurückgeschoben wird, dadurch gekennzeichnet, daß der Strangabzug in Abhängigkeit von der Dehnung bzw. Kontraktion der mit der Stranghaut in Kontakt stehenden Kokillenwandung gesteuert wird.1. A process for controlling the strand withdrawal from a horizontal continuous casting mold cooled with a cooling medium and having a material having a higher thermal conductivity, the strand being withdrawn step by step from the mold and the molten metal, preferably molten steel, coming discontinuously into the mold and, after forming a strand skin, the strand again withdrawn by one step and then pushed back by a partial step, characterized in that the strand withdrawal is controlled as a function of the expansion or contraction of the mold wall in contact with the strand skin. 2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß der Strangabzug in Abhängigkeit von der Dehnung bzw. Kontraktion der mit der Metallschmelze oder Stranghaut alternierend in Kontakt stehenden Kokillenwandung gesteuert wird.2. The method according to claim 1, characterized in that the strand withdrawal is controlled in dependence on the expansion or contraction of the mold wall alternately in contact with the molten metal or strand skin. 3. Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß die Messung der Dehnung bzw. Kontraktion im vom Kühlmedium durchflossenen Raum durchgeführt wird.3. The method according to claim 1 or 2, characterized in that the measurement of the expansion or contraction is carried out in the space through which the cooling medium flows. 4. Verfahren nach Anspruch 1, 2 oder 3, dadurch gekennzeichnet, daß bei einer bleibenden Kontraktion bzw. Dehnung der Kokille der Strang um weniger als eine Schrittlänge zurückgeschoben wird.4. The method according to claim 1, 2 or 3, characterized in that in the event of a permanent contraction or expansion of the mold, the strand is pushed back by less than one step length.
EP81890155A 1980-10-01 1981-09-24 Method of controlling the discharge of billets Expired EP0049238B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT81890155T ATE9656T1 (en) 1980-10-01 1981-09-24 METHOD OF CONTROLLING THE STRING DRAW-OFF.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3037048 1980-10-01
DE19803037048 DE3037048A1 (en) 1980-10-01 1980-10-01 METHOD FOR CONTROLLING THE STRAND DRAWER

Publications (3)

Publication Number Publication Date
EP0049238A2 true EP0049238A2 (en) 1982-04-07
EP0049238A3 EP0049238A3 (en) 1982-05-05
EP0049238B1 EP0049238B1 (en) 1984-10-03

Family

ID=6113327

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81890155A Expired EP0049238B1 (en) 1980-10-01 1981-09-24 Method of controlling the discharge of billets

Country Status (9)

Country Link
US (1) US4437509A (en)
EP (1) EP0049238B1 (en)
JP (1) JPS5785661A (en)
AT (1) ATE9656T1 (en)
BR (1) BR8106302A (en)
CA (1) CA1176818A (en)
DE (2) DE3037048A1 (en)
ES (1) ES8206232A1 (en)
ZA (1) ZA815683B (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0111000A1 (en) * 1982-05-31 1984-06-20 Nippon Kokan Kabushiki Kaisha Method of monitoring for damage to solidified shell of metal casting produce during removal of casting from horizontal continuous casting machine
EP0174146A2 (en) * 1984-09-05 1986-03-12 Nippon Kokan Kabushiki Kaisha Billet control method in a horizontal continuous casting system
EP0426501A1 (en) * 1989-11-03 1991-05-08 Steel Casting Engineering, Ltd. Motion control system E.G. for horizontal continuous caster

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58209455A (en) * 1982-05-31 1983-12-06 Nippon Kokan Kk <Nkk> Method for monitoring drawing of horizontal and continuous casting ingot
DE3426169C2 (en) * 1984-07-16 1986-06-05 Mannesmann AG, 4000 Düsseldorf Process and horizontal continuous casting mold for the horizontal continuous casting of metal, especially steel, into thin and wide strands
DE4137588C2 (en) * 1991-11-15 1994-10-06 Thyssen Stahl Ag Process for casting metals in a continuous caster
EP1582600A1 (en) * 2004-03-29 2005-10-05 Fata Aluminium S.p.A. Method and apparatus for cooling foundry castings
JP4690419B2 (en) 2004-11-12 2011-06-01 エルジー エレクトロニクス インコーポレイティド Discharge valve and valve assembly of reciprocating compressor provided with the same

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2504986B2 (en) * 1975-02-04 1977-05-18 Mannesmann AG, 4000 Düsseldorf METHOD AND DEVICE FOR CONTROLLING AND AVOIDING CRITICAL DEFORMATION OF THE STRAND SHELL
DE2501868B2 (en) * 1975-01-15 1977-12-08 Mannesmann AG, 4000 Düsseldorf PROCEDURE FOR CONTROLLING AND MONITORING CONTINUOUS STEEL CASTING
US4134440A (en) * 1974-09-16 1979-01-16 Nippon Kokan Kabushiki Kaisha Method of continuously casting steel
EP0008692A1 (en) * 1978-08-11 1980-03-19 Concast Holding Ag Method to avoid damage to cast guide elements in a continuous steel casting assembly
DE2340636C3 (en) * 1973-08-10 1980-04-24 Siemens Ag, 1000 Berlin Und 8000 Muenchen Device for the step-by-step extraction of a strand from a horizontal continuous casting mold

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2340636C3 (en) * 1973-08-10 1980-04-24 Siemens Ag, 1000 Berlin Und 8000 Muenchen Device for the step-by-step extraction of a strand from a horizontal continuous casting mold
US4134440A (en) * 1974-09-16 1979-01-16 Nippon Kokan Kabushiki Kaisha Method of continuously casting steel
DE2501868B2 (en) * 1975-01-15 1977-12-08 Mannesmann AG, 4000 Düsseldorf PROCEDURE FOR CONTROLLING AND MONITORING CONTINUOUS STEEL CASTING
DE2504986B2 (en) * 1975-02-04 1977-05-18 Mannesmann AG, 4000 Düsseldorf METHOD AND DEVICE FOR CONTROLLING AND AVOIDING CRITICAL DEFORMATION OF THE STRAND SHELL
EP0008692A1 (en) * 1978-08-11 1980-03-19 Concast Holding Ag Method to avoid damage to cast guide elements in a continuous steel casting assembly

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0111000A1 (en) * 1982-05-31 1984-06-20 Nippon Kokan Kabushiki Kaisha Method of monitoring for damage to solidified shell of metal casting produce during removal of casting from horizontal continuous casting machine
EP0111000A4 (en) * 1982-05-31 1984-09-19 Nippon Kokan Kk Method of monitoring for damage to solidified shell of metal casting produce during removal of casting from horizontal continuous casting machine.
EP0174146A2 (en) * 1984-09-05 1986-03-12 Nippon Kokan Kabushiki Kaisha Billet control method in a horizontal continuous casting system
EP0174146A3 (en) * 1984-09-05 1987-01-21 Nippon Kokan Kabushiki Kaisha Billet control method in a horizontal continuous casting system
EP0426501A1 (en) * 1989-11-03 1991-05-08 Steel Casting Engineering, Ltd. Motion control system E.G. for horizontal continuous caster

Also Published As

Publication number Publication date
EP0049238B1 (en) 1984-10-03
BR8106302A (en) 1982-06-22
ZA815683B (en) 1983-08-31
DE3037048A1 (en) 1982-04-29
CA1176818A (en) 1984-10-30
ATE9656T1 (en) 1984-10-15
EP0049238A3 (en) 1982-05-05
ES505707A0 (en) 1982-08-16
DE3166496D1 (en) 1984-11-08
ES8206232A1 (en) 1982-08-16
JPS5785661A (en) 1982-05-28
US4437509A (en) 1984-03-20

Similar Documents

Publication Publication Date Title
DE2207001A1 (en) Injection molding apparatus and method for synthetic resin
EP0049238B1 (en) Method of controlling the discharge of billets
DE3880095T2 (en) METHOD FOR QUALITY ASSESSMENT OF AN INJECTION MOLDED PRODUCT.
DE2414514A1 (en) CONTINUOUS CASTING
EP0353402B1 (en) Method for producing steel strip with a thickness of less than 10 mm
DE2104616B2 (en) Continuous casting mold for metals
DE2637311A1 (en) PROCESS FOR SINTERING OR MELTING CERAMIC OR REFRACTORY PRODUCTS
EP0026812B1 (en) Apparatus for producing amorphous metal strips
DE2122049C3 (en) Arrangement of a pair of insulated, electrical contact wires in a crawler mold to start the casting machine
DE2501868A1 (en) Controlling billet speed in continuous casting of steel - by measuring expansion of several sections on the mould wall
DE3215798A1 (en) METHOD AND DEVICE FOR SHEARING WARMED METAL RODS IN PRESSING BARS
DE2044855A1 (en) Method and device for the manufacture of sheet glass
EP0144795A2 (en) Method of oscillating a horizontal continuous-casting mould for metals, especially steel
DE69123036T2 (en) Process for pulling a cast strand in a horizontal continuous caster
DE4121611C1 (en)
DE2261176B2 (en) Device for detecting the tensile stress of strand-like material running between individual roll stands of a rolling mill and for changing the speed of the rolls of the individual roll stands
DE870324C (en) Method and device for the automatic feeding of the cast material during continuous casting
DE4137588C2 (en) Process for casting metals in a continuous caster
DE3523025A1 (en) Method and apparatus for bending elongated metallic workpieces
DE2156382B2 (en) Method for guiding a layer of slag floating on the bath level within a continuous casting mold
DE3307176C2 (en)
DE3521670A1 (en) METHOD AND DEVICE FOR PUMPING STEEL
DE3706490C2 (en) Device and method for EDM wire cutting with a wire electrode made from a melt
DE3207091A1 (en) CONTINUOUS METHOD
DE3232662C2 (en)

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Designated state(s): AT BE CH DE FR GB IT LU NL SE

AK Designated contracting states

Designated state(s): AT BE CH DE FR GB IT LU NL SE

17P Request for examination filed

Effective date: 19821102

ITF It: translation for a ep patent filed
GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Designated state(s): AT BE CH DE FR GB IT LI LU NL SE

REF Corresponds to:

Ref document number: 9656

Country of ref document: AT

Date of ref document: 19841015

Kind code of ref document: T

REF Corresponds to:

Ref document number: 3166496

Country of ref document: DE

Date of ref document: 19841108

ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19850930

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: AT

Payment date: 19860814

Year of fee payment: 6

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 19870930

Year of fee payment: 7

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19880924

Ref country code: AT

Effective date: 19880924

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Effective date: 19880925

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Effective date: 19880930

Ref country code: CH

Effective date: 19880930

Ref country code: BE

Effective date: 19880930

BERE Be: lapsed

Owner name: BOHLER A.G.

Effective date: 19880930

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Effective date: 19890401

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19890531

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

GBPC Gb: european patent ceased through non-payment of renewal fee
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19890601

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

EUG Se: european patent has lapsed

Ref document number: 81890155.5

Effective date: 19890614