EP0102937B1 - Gauge control system of a cold rolling mill - Google Patents

Gauge control system of a cold rolling mill Download PDF

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Publication number
EP0102937B1
EP0102937B1 EP19830890081 EP83890081A EP0102937B1 EP 0102937 B1 EP0102937 B1 EP 0102937B1 EP 19830890081 EP19830890081 EP 19830890081 EP 83890081 A EP83890081 A EP 83890081A EP 0102937 B1 EP0102937 B1 EP 0102937B1
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EP
European Patent Office
Prior art keywords
rolling stock
resistance
deformation
thickness
rolling
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EP19830890081
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German (de)
French (fr)
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EP0102937A1 (en
Inventor
Walther Dipl.-Ing. Ossoinig
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Voestalpine AG
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Voestalpine AG
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
    • B21B37/16—Control of thickness, width, diameter or other transverse dimensions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B2261/00—Product parameters
    • B21B2261/22—Hardness

Definitions

  • the invention relates to a device for adjusting the control of a cold rolling mill with a controller that controls the actuator of the stand depending on the measured thickness of the rolling stock, and with a computer that is connected to a sensor for a measured value that changes with the resistance to deformation of the rolling stock is and depending on this measured value, the controller is provided with a program-determined correction value for the scaffolding adjustment resulting from the determined target / actual value difference.
  • the strip thickness of the rolling stock being discharged is measured for the control of a cold rolling mill stand and the stand position is controlled by a controller depending on a target-actual value difference that may have been determined, the problem arises that a thickness measuring device can only be arranged at a certain distance from the roll gap, which is due to The conveying time required to run through the conveying path between the roll gap and the thickness measuring device requires a dead time for the control. Deviations in thickness within this conveyor section can therefore in principle not be corrected with a simple thickness measurement after the roll gap.
  • the strip thickness is therefore measured not only after the roll gap, but also before the roll gap, so that differences in the thickness of the rolling stock can be detected even before it enters the roll gap and can be taken into account by means of a corresponding roll adjustment if the rolling stock spot deviations show the Passes through the nip.
  • a feedforward control for the thickness control is consequently achieved, which considerably improves the rolling result.
  • the thickness of a cold-rolled strip does not only depend on the thickness of the strip in front of the roll gap, but also on the resistance to deformation of the rolling stock when the roll position remains the same. Since the resistance to deformation in turn depends on the chemical-physical composition of the rolling stock and its treatment, a change in the resistance to deformation over the length of the rolling stock must be expected.
  • the changing resistance to deformation of the rolling stock must also be taken into account when regulating the thickness. Such consideration of the deformation resistance is difficult, however, because the deformation resistance cannot be directly measured. Since the rolling force to be applied depends on the resistance to deformation of the rolling stock, the rolling force is also used to calculate a correction value for the stand position resulting from the setpoint-actual value difference.
  • a disadvantage of this known device which allows the detection of changing rolling stock conditions in front of the roll gap, is that a sensor is provided for determining the thickness and hardness of the rolling stock, which consists of two measuring heads which can be pressed onto the rolling stock from opposite sides under a predetermined force , so that the distance between these measuring heads depends on both the thickness of the rolling stock and its hardness.
  • a sensor is provided for determining the thickness and hardness of the rolling stock, which consists of two measuring heads which can be pressed onto the rolling stock from opposite sides under a predetermined force , so that the distance between these measuring heads depends on both the thickness of the rolling stock and its hardness.
  • the invention is therefore based on the object of improving a device for adjusting the control of a cold rolling mill so that the rolling result can be improved by taking more account of the influence of a changing resistance to deformation.
  • the sensor for determining the resistance to deformation of the rolling stock consists of a magnetizing device for the rolling stock with at least one excitation coil and a measuring sensor assigned to the magnetizing device, for example a measuring coil or a Hall generator.
  • this special transducer enables a continuous, non-contact measurement of the hardness of the rolling stock, even for non-ferromagnetic rolling stock.
  • the excitation coil induces eddy currents in the rolling stock, the size, phase position and distribution of which are largely determined by the physical properties and the electrical conductivity.
  • the magnetic field caused by these induced eddy currents can be detected either directly by a Hall generator or indirectly by means of a voltage induced in a measuring coil, so that measurement values can be obtained from such sensors, which also allow a conclusion to be drawn about the hardness of the material being examined.
  • Such devices for magnetic testing of metal strips are known per se and are usually used for quality control of finished strips.
  • the correction factor determined by the computer can be related more precisely to fluctuations in the deformation resistance in accordance with the actual conditions.
  • the cold rolling stand 1 shown has an employment for the upper roll 2, an actuator 3 in the form of a hydraulic cylinder being used. Instead of this hydraulic adjustment, an electromechanical top roller adjustment could also be provided.
  • a controller 4 is used to control the hydraulic cylinder 3 and acts on a control valve 6 for the hydraulic medium line 7 via a control line 5.
  • the controller 4 thus controls the stand setting as a function of the setpoint / actual value difference of the measured thickness of the rolling stock 8.
  • a measuring value transmitter 9 for the actual value of the rolling stock thickness is assigned to the cold rolling stand 1. Since it is only a question of the detection of the actual value of the thickness, the transmitter 9 can have any structure.
  • a thickness measuring device is shown which scans the thickness of the rolling stock with the aid of a measuring roller 10.
  • a sensor 11 with the same effect is also provided on the inlet side for the thickness detection of the rolling stock.
  • the measured value of the transducer 11 is fed to a computer 12, which determines a correction value for the stand position resulting from the setpoint-actual value difference, in order to be able to take irregularities of the rolling stock in front of the roll gap into account when setting up the stand, if the areas of the rolling stock exhibiting these irregularities Run through the nip.
  • knowledge of the rolling stock speed is required so that the running time of the rolling stock 8 from the measuring point to the roll gap can be taken into account.
  • Corresponding speed sensors 13 in front of and behind the roll gap therefore detect the rolling stock speed before and after the roll gap and pass these measured values on to the computer 12.
  • the scaffold adjustment is thus corrected with a delay adapted to the running time of the belt.
  • the correction value determined by the computer 12 takes into account not only the disturbance variables caused by fluctuations in the thickness of the incoming rolling stock, but also disturbance variables which occur as a result of fluctuations in the resistance to deformation. For this purpose, it is not the rolling force but the hardness of the rolling stock 8 that is measured, with the aid of a measuring sensor 14.
  • This measuring sensor 14 advantageously consists of a magnetizing device having an excitation coil which generates eddy currents in the rolling stock, the magnetic field of which is detected by a sensor is formed by either a Hall generator or a measuring coil. Since the size, phase and distribution of the eddy currents change with the physical properties of the rolling stock, a measurement of the hardness of the rolling stock can be derived from the eddy currents.
  • This hardness changes largely proportionally with the resistance to deformation, so that changes in the resistance to deformation can be detected via the measured value for the hardness.
  • the advantage of such a detection of the deformation resistance is not only due to the greater accuracy with which changes in the deformation resistance can be determined, but above all that changes in the deformation resistance of the rolling stock, which lead to changes in the deformation resistance, are recognized even before the roll gap and can therefore be taken into account when setting up the scaffolding.
  • the computer 12 can therefore calculate a correction value for the respective scaffold position, which also takes account of changes in the resistance to deformation in advance. This enables a very precise control of the strip thickness because the disturbance variables in front of the roll gap can be recorded and taken into account when setting up the scaffolding.
  • the computer 12 can of course also correct other influencing variables on the basis of its program, if this is desired. First and foremost, the resilient yielding of individual scaffolding parts under appropriate loads and the floating of the bearings are to be mentioned.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Control Of Metal Rolling (AREA)

Description

Die Erfindung bezieht sich auf eine Vorrichtung zur Anstellregelung eines Kaltwalzgerüstes mit einem Regler, der den Stelltrieb der Gerüstanstellung in Abhängigkeit von der gemessenen Dicke des Walzgutes steuert, und mit einem Rechner, der an einen Meßwertgeber für einen sich mit dem Formänderungswiderstand des Walzgutes ändernden Meßwert angeschlossen ist und in Abhängigkeit von diesem Meßwert den Regler mit einem programmbedingt ermittelten Korrekturwert für die sich aus der festgestellten Soll-Istwertdifferenz ergebende Gerüstanstellung beaufschlagt.The invention relates to a device for adjusting the control of a cold rolling mill with a controller that controls the actuator of the stand depending on the measured thickness of the rolling stock, and with a computer that is connected to a sensor for a measured value that changes with the resistance to deformation of the rolling stock is and depending on this measured value, the controller is provided with a program-determined correction value for the scaffolding adjustment resulting from the determined target / actual value difference.

Wird zur Anstellregelung eines Kaltwalzgerüstes die Banddicke des auslaufenden Walzgutes gemessen und die Gerüstanstellung in Abhängigkeit von einer allenfalls festgestellten Soll-Istwertdifferenz über einen Regler gesteuert, so ergibt sich das Problem, daß ein Dickenmeßgerät erst in einer bestimmten Entfernung vom Walzspalt angeordnet werden kann, was aufgrund der zum Durchlaufen der Förderstrecke zwischen Walzspalt und Dickenmeßgerät erforderlichen Förderzeit eine Totzeit für die Regelung bedingt. Dickenabweichungen innerhalb dieser Förderstrecke können daher grundsätzlich nicht mit einer einfachen Dickenmessung nach dem Walzspalt ausgeregelt werden. Es wird daher zur Vermeidung dieser Nachteile die Banddicke nicht nur nach dem Walzspalt, sondern auch vor dem Walzspalt gemessen, so daß Dickenunterschiede des Walzgutes bereits vor dem Einlauf in den Walzspalt erfaßt und durch eine entsprechende Walzenanstellung berücksichtigt werden können, wenn die Dickenabweichungen aufweisende Walzgutstelle den Walzspalt durchläuft. Es wird folglich eine Störgrößenaufschaltung für die Dickenregelung erreicht, die das Walzergebnis erheblich verbessert. Die Dicke eines kaltgewalzten Bandes hängt bei einer gleichbleibenden Walzenanstellung nicht nur von der Dicke des Bandes vor dem Walzspalt, sondern auch vom Formänderungswiderstand des Walzgutes ab. Da der Formänderungswiderstand seinerseits von der chemisch-physikalischen Zusammensetzung des Walzgutes und dessen Behandlung abhängt, muß mit einer Änderung des Formänderungswiderstandes über die Länge des Walzgutes gerechnet werden. Um das Walzergebnis zu verbessern, ist daher bei der Dickenregelung auch der sich ändernde Formänderungswiderstand des Walzgutes zu berücksichtigen. Eine solche Berücksichtigung des Formänderungswiderstandes stößt jedoch auf Schwierigkeiten, weil der Formänderungswiderstand meßtechnisch nicht unmittelbar erfaßt werden kann. Da die aufzubringende Walzkraft vom Formänderungswiderstand des Walzgutes abhängt, wird die Walzkraft auch dazu verwendet, einen Korrekturwert für die sich aus der festgestellten Soll-Istwertdifferenz ergebende Gerüstanstellung zu errechnen. Durch die Beaufschlagung des Reglers mit einem solchen Korrekturwert, der zusätzlich die Einflüsse der federnden Nachgiebigkeit der belasteten Gerüstteile berücksichtigen kann, kann zwar eine weitere Verbesserung des Walzergebnisses erreicht werden, doch bleibt eine solche Regelung grundsätzlich ungenau und mit Restfehlern behaftet, weil einerseits die Walzkraft nicht nur vom Formänderungswiderstand, sondern auch von der Dickenabnahme und vom Radius der Walzen abhängt und anderseits eine Änderung der Walzkraft als Folge einer Änderung des Formänderungswiderstandes auftritt, was eine Berücksichtigung des geänderten Formänderungswiderstandes nur im nachhinein erlaubt.If the strip thickness of the rolling stock being discharged is measured for the control of a cold rolling mill stand and the stand position is controlled by a controller depending on a target-actual value difference that may have been determined, the problem arises that a thickness measuring device can only be arranged at a certain distance from the roll gap, which is due to The conveying time required to run through the conveying path between the roll gap and the thickness measuring device requires a dead time for the control. Deviations in thickness within this conveyor section can therefore in principle not be corrected with a simple thickness measurement after the roll gap. To avoid these disadvantages, the strip thickness is therefore measured not only after the roll gap, but also before the roll gap, so that differences in the thickness of the rolling stock can be detected even before it enters the roll gap and can be taken into account by means of a corresponding roll adjustment if the rolling stock spot deviations show the Passes through the nip. A feedforward control for the thickness control is consequently achieved, which considerably improves the rolling result. The thickness of a cold-rolled strip does not only depend on the thickness of the strip in front of the roll gap, but also on the resistance to deformation of the rolling stock when the roll position remains the same. Since the resistance to deformation in turn depends on the chemical-physical composition of the rolling stock and its treatment, a change in the resistance to deformation over the length of the rolling stock must be expected. In order to improve the rolling result, the changing resistance to deformation of the rolling stock must also be taken into account when regulating the thickness. Such consideration of the deformation resistance is difficult, however, because the deformation resistance cannot be directly measured. Since the rolling force to be applied depends on the resistance to deformation of the rolling stock, the rolling force is also used to calculate a correction value for the stand position resulting from the setpoint-actual value difference. By applying such a correction value to the controller, which can also take into account the effects of the resilient flexibility of the loaded scaffolding parts, a further improvement in the rolling result can be achieved, but such a regulation remains fundamentally imprecise and has residual errors because, on the one hand, the rolling force does not depends only on the resistance to deformation, but also on the decrease in thickness and the radius of the rolls, and on the other hand a change in the rolling force occurs as a result of a change in the resistance to deformation, which allows the changed resistance to deformation to be taken into account only afterwards.

Zur Vermeidung dieser Nachteile ist es schließlich bekannt (US-PS 3 665 743), die Gerüstanstellung über ein Signal zu steuern, das in Abhängigkeit von Dickenschwankungen und von Schwankungen der Härte des Walzgutes seine Größe verändert. Da sich der zu berücksichtigende Formänderungswiderstand selbst aus der Formänderungsfestigkeit des Walzgutes und dem Fließwiderstand zusammensetzt, der auf der Behinderung des Materialflusses durch die Reibung an den Walzen beruht, kann über Härteschwankungen des Walzgutes der sich ändernde -Formänderungswiderstand berücksichtigt werden. Der Fließwiderstand ist nämlich in der Praxis keinen entscheidenden Veränderungen unterworfen, so daß wegen der unmittelbaren Abhängigkeit zwischen der Formänderungsfestigkeit und der Härte des Walzgutes mit der Berücksichtigung der Walzguthärte der Formänderungswiderstand in die Steuerung der Gerüstanstellung eingeht. Nachteilig bei dieser bekannten Vorrichtung, die das Erfassen sich verändernder Walzgutverhältnisse vor dem Walzspalt erlaubt, ist allerdings, daß zur Bestimmung der Dicke und Härte des Walzgutes ein Meßwertgeber vorgesehen ist, der aus zwei von entgegengesetzten Seiten unter einer vorbestimmten Kraft an das Walzgut andrückbaren Meßköpfen besteht, so daß der Abstand dieser Meßköpfe voneinander sowohl von der Dicke des Walzgutes als auch von dessen Härte abhängt. Da jedoch die Einflüsse von Dickenschwankungen und Härteschwankungen unterschiedlich sind und zwischen diesen Einflüssen grundsätzlich nicht unterschieden werden kann, bleibt eine solche Regelung der Gerüstanstellung mit Fehlern behaftet.To avoid these disadvantages, it is finally known (US Pat. No. 3,665,743) to control the stand setting using a signal which changes its size as a function of thickness fluctuations and fluctuations in the hardness of the rolling stock. Since the deformation resistance to be taken into account is itself composed of the deformation resistance of the rolling stock and the flow resistance, which is based on the hindrance of the material flow due to the friction on the rolls, the changing deformation resistance can be taken into account via fluctuations in hardness of the rolling stock. In practice, the flow resistance is not subject to any decisive changes, so that due to the direct dependency between the deformation resistance and the hardness of the rolling stock, the deformation resistance is taken into account in the control of the stand setting when the rolling stock hardness is taken into account. A disadvantage of this known device, which allows the detection of changing rolling stock conditions in front of the roll gap, is that a sensor is provided for determining the thickness and hardness of the rolling stock, which consists of two measuring heads which can be pressed onto the rolling stock from opposite sides under a predetermined force , so that the distance between these measuring heads depends on both the thickness of the rolling stock and its hardness. However, since the influences of fluctuations in thickness and fluctuations in hardness are different and it is fundamentally not possible to differentiate between these influences, such a regulation of the scaffolding position is subject to errors.

Der Erfindung liegt somit die Aufgabe zugrunde, eine Vorrichtung zur Anstellregelung eines Kaltwalzgerüstes so zu verbessern, daß das Walzergebnis durch eine genauere Berücksichtigung des Einflusses eines sich ändernden Formänderungswiderstandes verbessert werden kann.The invention is therefore based on the object of improving a device for adjusting the control of a cold rolling mill so that the rolling result can be improved by taking more account of the influence of a changing resistance to deformation.

Die Erfindung löst die gestellte Aufgabe dadurch, daß der Meßwertgeber zur Bestimmung des Formänderungswiderstandes des Walzgutes aus einer Magnetisierungseinrichtung für das Walzgut mit wenigstens einer Erregerspule und aus einem der Magnetisierungseinrichtung zugeordneten Meßfühler, beispielsweise einer Meßspule oder einem Hallgenerator, besteht.The invention solves this problem in that the sensor for determining the resistance to deformation of the rolling stock consists of a magnetizing device for the rolling stock with at least one excitation coil and a measuring sensor assigned to the magnetizing device, for example a measuring coil or a Hall generator.

Durch das Vorsehen dieses besonderen Meßwertgebers wird eine fortlaufende, berührungslose Messung der Härte des Walzgutes für sich möglich, und zwar auch bei nicht ferromagnetischem Walzgut. Durch die Erregerspule werden im Walzgut Wirbelströme induziert, deren Größe, Phasenlage und Verteilung weitgehend durch die physikalischen Eigenschaften und die elektrische Leitfähigkeit bestimmt werden. Das durch diese induzierten Wirbelströme bedingte magnetische Feld kann entweder unmittelbar durch einen Hallgenerator oder mittelbar über eine in einer Meßspule induzierte Spannung erfaßt werden, so daß durch solche Meßfühler Meßwerte gewonnen werden, die einen Rückschluß auch auf die Härte des untersuchten Werkstoffes zulassen. Solche Vorrichtungen zur magnetischen Prüfung von Metallbändern sind an sich bekannt und werden üblicherweise zur Qualitätskontrolle von fertiggestellten Bändern eingesetzt.The provision of this special transducer enables a continuous, non-contact measurement of the hardness of the rolling stock, even for non-ferromagnetic rolling stock. The excitation coil induces eddy currents in the rolling stock, the size, phase position and distribution of which are largely determined by the physical properties and the electrical conductivity. The magnetic field caused by these induced eddy currents can be detected either directly by a Hall generator or indirectly by means of a voltage induced in a measuring coil, so that measurement values can be obtained from such sensors, which also allow a conclusion to be drawn about the hardness of the material being examined. Such devices for magnetic testing of metal strips are known per se and are usually used for quality control of finished strips.

Mit der Erfassung der Härte des Walzgutes unabhängig von der Dickenmessung wird es in vorteilhafter Weise möglich, den Einfluß eines sich ändernden Formänderungswiderstandes durch eine entsprechende Störgrößenaufschaltung der Anstellregelung auszuregeln, so daß das Walzen von Bändern mit höherer Qualität bei vergleichbarem Ausgangsmaterial oder das Walzen von Bändern gleicher Qualität bei schlechterem Ausgangsmaterial möglich wird. Der vom Rechner bestimmte Korrekturfaktor kann ja entsprechend den tatsächlichen Verhältnissen genauer auf Schwankungen des Formänderungswiderstandes bezogen werden.With the detection of the hardness of the rolling stock regardless of the thickness measurement, it is advantageously possible to compensate for the influence of a changing resistance to deformation by a corresponding feedforward control of the adjustment control, so that the rolling of strips of higher quality with comparable starting material or the rolling of strips of the same Quality with poorer raw material becomes possible. The correction factor determined by the computer can be related more precisely to fluctuations in the deformation resistance in accordance with the actual conditions.

In der Zeichnung ist der Erfindungsgegenstand in einem Ausführungsbeispiel schematisch dar-' gestellt, und zwar wird ein Kaltwalzgerüst mit einer erfindungsgemäßen Vorrichtung zur Anstellregelung in einem vereinfachten Blockschaltbild gezeigt.In the drawing, the subject matter of the invention is shown schematically in an exemplary embodiment, namely a cold rolling stand with a device according to the invention for pitch control is shown in a simplified block diagram.

Das dargestellte Kaltwalzgerüst 1 besitzt eine Anstellung für die Oberwalze 2, wobei ein Stelltrieb 3 in Form eines Hydraulikzylinders zum Einsatz kommt. An Stelle dieser hydraulischen Anstellung könnte aber auch eine elektromechanische Oberwalzenanstellung vorgesehen sein. Zur Steuerung des Hydraulikzylinders 3 dient ein Regler 4, der über eine Steuerleitung 5 ein Steuerventil 6 für die Hydraulikmittelleitung 7 beaufschlagt. Der Regler 4 steuert somit die Gerüstanstellung in Abhängigkeit von der Soll-Istwertdifferenz der gemessenen Dicke des Walzgutes 8. Zu diesem Zweck ist dem Kaltwalzgerüst 1 auslaufseitig ein Meßwertgeber 9 für den Istwert der Walzgutdicke zugeordnet. Da es lediglich auf die Erfassung des Istwertes der Dicke ankommt, kann der Meßwertgeber 9 an sich einen beliebigen Aufbau haben. Aus Übersichlichkeitsgründen ist ein Dickenmeßgerät dargestellt, das die Walzgutdicke mit Hilfe einer Meßrolle 10 abtastet.The cold rolling stand 1 shown has an employment for the upper roll 2, an actuator 3 in the form of a hydraulic cylinder being used. Instead of this hydraulic adjustment, an electromechanical top roller adjustment could also be provided. A controller 4 is used to control the hydraulic cylinder 3 and acts on a control valve 6 for the hydraulic medium line 7 via a control line 5. The controller 4 thus controls the stand setting as a function of the setpoint / actual value difference of the measured thickness of the rolling stock 8. For this purpose, a measuring value transmitter 9 for the actual value of the rolling stock thickness is assigned to the cold rolling stand 1. Since it is only a question of the detection of the actual value of the thickness, the transmitter 9 can have any structure. For reasons of clarity, a thickness measuring device is shown which scans the thickness of the rolling stock with the aid of a measuring roller 10.

Damit Änderungen der Banddicke auch einlaufseitig erfaßt werden können, was eine Störgrößenbeaufschlagung des Reglers 4 ermöglicht, ist auch einlaufseitig ein gleichwirkender Meßwertgeber 11 für die Dickenerfassung des Walzgutes vorgesehen. Der Meßwert des Meßwertgebers 11 wird dabei einem Rechner 12 zugeführt, der einen Korrekturwert für die sich aus der festgestellten Soll-Istwertdifferenz ergebende Gerüstanstellung ermittelt, um Unregelmäßigkeiten des Walzgutes vor dem Walzspalt bereits bei der Gerüstanstellung berücksichtigen zu können, wenn die diese Unregelmäßigkeiten aufweisenden Walzgutbereiche den Walzspalt durchlaufen. Für eine solche Vorsteuerung ist die Kenntnis der Walzgutgeschwindigkeit erforderlich, damit die Laufzeit des Walzgutes 8 von der Meßstelle bis zum Walzspalt berücksichtigt werden kann. Entsprechende Geschwindigkeitsgeber 13 vor und hinter dem Walzspalt erfassen daher die Walzgutgeschwindigkeit vor und nach dem Walzspalt und geben diese Meßwerte an den Rechner 12 weiter. Die Korrektur der Gerüstanstellung erfolgt somit mit einer an die Laufzeit des Bandes angepaßten Verzögerung.So that changes in the strip thickness can also be detected on the inlet side, which enables the disturbance variable to be applied to the controller 4, a sensor 11 with the same effect is also provided on the inlet side for the thickness detection of the rolling stock. The measured value of the transducer 11 is fed to a computer 12, which determines a correction value for the stand position resulting from the setpoint-actual value difference, in order to be able to take irregularities of the rolling stock in front of the roll gap into account when setting up the stand, if the areas of the rolling stock exhibiting these irregularities Run through the nip. For such pilot control, knowledge of the rolling stock speed is required so that the running time of the rolling stock 8 from the measuring point to the roll gap can be taken into account. Corresponding speed sensors 13 in front of and behind the roll gap therefore detect the rolling stock speed before and after the roll gap and pass these measured values on to the computer 12. The scaffold adjustment is thus corrected with a delay adapted to the running time of the belt.

Der vom Rechner 12 ermittelte Korrekturwert berücksichtigt aber nicht nur die durch Dickenschwankungen des einlaufenden Walzgutes bedingten Störgrößen, sondern auch Störgrößen, die zufolge von Schwankungen des Formänderungswiderstandes auftreten. Zu diesem Zweck wird nicht die Walzkraft, sondern die Härte des Walzgutes 8 gemessen, und zwar mit Hilfe eines Meßwertgebers 14. Dieser Meßwertgeber 14 besteht in vorteilhafter Weise aus einer eine Erregerspule aufweisenden Magnetisierungseinrichtung, die im Walzgut Wirbelströme erzeugt, deren Magnetfeld über einen Meßfühler erfaßt wird, der entweder durch einen Hallgenerator oder eine Meßspule gebildet wird. Da sich die Größe, Phase und Verteilung der Wirbelströme mit den physikalischen Eigenschaften des Walzgutes ändern, kann über die Wirbelströme ein Meßwert für die Härte des Walzgutes abgeleitet werden. Diese Härte ändert sich weitgehend proportional mit dem Formänderungswiderstand, so daß über den Meßwert für die Härte Änderungen des Formänderungswiderstandes erfaßt werden können. Der Vorteil einer solchen Erfassung des Formänderungswiderstandes liegt nicht nur in der größeren Genauigkeit begründet, mit der Änderungen des Formänderungswiderstandes bestimmt werden können, sondern vor allem darin, daß Änderungen der Formänderungsfestigkeit des Walzgutes, die zu Änderungen des Formänderungswiderstandes führen, bereits vor dem Walzspalt erkannt und daher bei der Gerüstanstellung berücksichtigt werden können. Der Rechner 12 kann daher bei einem entsprechenden Programm einen Korrekturwert für die jeweilige Gerüstanstellung errechnen, der auch Änderungen des Formänderungswiderstandes im vorhinein berücksichtigt. Damit wird eine sehr genaue Regelung der Banddicke möglich, weil eben die Störgrößen vor dem Walzspalt erfaßt und bei der Gerüstanstellung beachtet werden können. Der Rechner 12 kann auf Grund seines Programmes selbstverständlich auch andere Einflußgrößen korrigieren, wenn dies erwünscht ist. In erster Linie ist hier das federnde Nachgeben einzelner Gerüstteile bei entsprechenden Belastungen und das Aufschwimmen der Lager anzuführen.The correction value determined by the computer 12 takes into account not only the disturbance variables caused by fluctuations in the thickness of the incoming rolling stock, but also disturbance variables which occur as a result of fluctuations in the resistance to deformation. For this purpose, it is not the rolling force but the hardness of the rolling stock 8 that is measured, with the aid of a measuring sensor 14. This measuring sensor 14 advantageously consists of a magnetizing device having an excitation coil which generates eddy currents in the rolling stock, the magnetic field of which is detected by a sensor is formed by either a Hall generator or a measuring coil. Since the size, phase and distribution of the eddy currents change with the physical properties of the rolling stock, a measurement of the hardness of the rolling stock can be derived from the eddy currents. This hardness changes largely proportionally with the resistance to deformation, so that changes in the resistance to deformation can be detected via the measured value for the hardness. The advantage of such a detection of the deformation resistance is not only due to the greater accuracy with which changes in the deformation resistance can be determined, but above all that changes in the deformation resistance of the rolling stock, which lead to changes in the deformation resistance, are recognized even before the roll gap and can therefore be taken into account when setting up the scaffolding. With a corresponding program, the computer 12 can therefore calculate a correction value for the respective scaffold position, which also takes account of changes in the resistance to deformation in advance. This enables a very precise control of the strip thickness because the disturbance variables in front of the roll gap can be recorded and taken into account when setting up the scaffolding. The computer 12 can of course also correct other influencing variables on the basis of its program, if this is desired. First and foremost, the resilient yielding of individual scaffolding parts under appropriate loads and the floating of the bearings are to be mentioned.

Claims (1)

  1. Apparatus for an automatic control of the roll adjustment in a cold-rolling stand (1), comprising a controller for controlling the roll adjusting mechanism (3) of the stand in dependence on the measured thickness of the rolled stock (8), and a computer (12), which is connected to a pickup (14) for measuring a parameter which changes with the resistance of the rolled stock (8) to deformation and for delivering to the controller (4) a correcting signal, which has been determined in dependence on said parameter in accordance with a program and is used to effect in the stand the roll adjustment required in dependence on the detected difference between the desired and actual values, characterized in that the pickup (14) for measuring the resistance of the rolled stock (8) to deformation comprises magnetizing means for magnetizing the rolled stock, including at least one exciter coil, and further comprises a sensor, which is associated with the magnetizing means and consists, e. g., of a sensor coil or a Hall generator.
EP19830890081 1982-09-07 1983-05-11 Gauge control system of a cold rolling mill Expired EP0102937B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AT333282A AT374705B (en) 1982-09-07 1982-09-07 DEVICE FOR CONTROLLING A COLD ROLLING DEVICE
AT3332/82 1982-09-07

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EP0102937A1 EP0102937A1 (en) 1984-03-14
EP0102937B1 true EP0102937B1 (en) 1985-11-21

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DE19831480C1 (en) * 1998-07-14 2000-01-13 Schloemann Siemag Ag Process for presetting cold forming plants
EP2349598A1 (en) * 2008-10-17 2011-08-03 Siemens Vai Metals Technologies SAS Device and method for setting up an installation for the conversion of steel strip as a function of an arbitrary thickness of the said steel strip
EP2662158A1 (en) * 2012-05-07 2013-11-13 Siemens Aktiengesellschaft Method for processing milled goods and milling system
CN117019882B (en) * 2023-08-24 2024-04-16 北京科技大学 Automatic thickness feedforward control method for strip steel cold continuous rolling in consideration of hot rolling incoming material information

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GB1270868A (en) * 1968-09-23 1972-04-19 Froehling Fa Josef Methods and apparatus for controlling a machine for processing strip material

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EP0102937A1 (en) 1984-03-14
AT374705B (en) 1984-05-25
DE3361280D1 (en) 1986-01-02
ATA333282A (en) 1983-10-15

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