EP1161313A1 - Control of surface evenness for obtaining even cold strip - Google Patents

Control of surface evenness for obtaining even cold strip

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Publication number
EP1161313A1
EP1161313A1 EP00929223A EP00929223A EP1161313A1 EP 1161313 A1 EP1161313 A1 EP 1161313A1 EP 00929223 A EP00929223 A EP 00929223A EP 00929223 A EP00929223 A EP 00929223A EP 1161313 A1 EP1161313 A1 EP 1161313A1
Authority
EP
European Patent Office
Prior art keywords
strip
distribution
temperature
flatness
stresses
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
EP00929223A
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German (de)
French (fr)
Other versions
EP1161313B1 (en
Inventor
Folker Haase
Wolfgang Sauer
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.)
SMS Siemag AG
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SMS Demag AG
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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B21MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21BROLLING OF METAL
    • B21B37/00Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
    • B21B37/28Control of flatness or profile during rolling of strip, sheets or plates
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B21MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21BROLLING OF METAL
    • B21B2261/00Product parameters
    • B21B2261/20Temperature
    • B21B2261/21Temperature profile

Definitions

  • the invention relates to a method for rolling a rolled strip in a strip mill with at least two roll stands or a single stand, each with upper and lower optionally adjustable work rolls, which are supported, if necessary, directly or via intermediate rolls on support rolls and in which at least one stitch is used to change the condition of the rolled strip is rolled, a target stress distribution or any target unevenness form is specified for the rolled strip and compared with the actually achieved stress distribution, and available mechanically or physically effective actuators are used in such a way that the difference between the predetermined and the actually achieved stress distribution is as large as possible is minimized.
  • the flatness measurement of cold rolled strip is usually done using
  • Flatness measuring rollers which measure the current tension distribution over the bandwidth. The measurement is usually carried out on the outlet side of the roll stand, where average strip temperatures between 80 and 160 ° C occur. The same applies analogously to other metals such as aluminum or copper.
  • the contour of the roll gap should be controlled so that the
  • Band flatness or a specific form of flatness is retained or is achieved.
  • the measured variable is the stress distribution in the warm band, which is associated with the temperature-induced stress described (in the example above, more than 25 N / mm 2 ).
  • a voltage component corresponding to the temperature-induced voltage, but with the opposite sign is additionally superimposed in the cooled band of the target unevenness form.
  • target stress distributions or target non-flatness shapes could in principle also be specified for a given product together with a given rolling or special cooling strategy in such a way that the cooled product is sufficiently flat.
  • search for the required objective functions or non-flatness forms is a complex empirical one
  • Cooling lubricant flows and the larger surface area / volume ratio at the strip edge, especially when wound up, as a result of which the temperature usually drops towards the strip edge.
  • the degree of deformation when rolling thin steel strips is usually higher at the strip edge because of the embedding of the rolled material in the roller, and nevertheless the temperature at the edge is lower overall due to the effects just described.
  • the aim of the present invention is to find a method for flatness control with which it is no longer necessary to distinguish between the measurable flatness in the warm state immediately behind the roll gap and the different cold uneveness forms of the cooled bundles for different products and rolling strategies, and with the warm state the same flatness or non-flatness shapes can be specified.
  • the strip temperature distribution over the strip width is also detected, and from this the tension distribution is calculated, which would occur after the strip had cooled down if the strip was in the warm state with the one behind Roll gap existing temperature distribution would be stress-free, and that this temperature-induced stress distribution is used to correct the actually achieved stress before it is compared with the target non-flatness form.
  • Formulation of the target function for flatness can be done in such a way that the best possible flatness of the cooled covenant is achieved directly.
  • the invention does not use the temperature measurement as a measurement variable directly linked to the unevenness (this task is performed by the tension measuring roller), but according to the technological knowledge of the Unplanarity causes as a supplementary correction quantity to the tensile stress in the hot strip, which can now be measured directly, so that the control can reach cold strip with a defined flatness in each individual case.
  • the strip is computationally broken down into strips in the running direction, conveniently, but not necessarily with a strip width, as specified by the tension measuring roller used. In many technically executed cases this is approx. 52 mm and usually also corresponds to the division of the nozzles on the chilled beam. For each of these strips i, an average temperature T is determined from the temperature signals. If the temperature signals are not in one - in the specified
  • Example - given a 52 mm division an interpolation must first be made to this strip division.
  • an average temperature T m is calculated over the entire bandwidth.
  • the method according to the invention has further advantages: By eliminating the inspection of the cooled coil, the determination of target unevenness for the hot strip is considerably simplified. Scattered cold unevenness due to temperature fluctuations are avoided. Differences in target unevenness for different products are reduced.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Control Of Metal Rolling (AREA)
  • Metal Rolling (AREA)
  • Train Traffic Observation, Control, And Security (AREA)
  • Electrotherapy Devices (AREA)
  • Outside Dividers And Delivering Mechanisms For Harvesters (AREA)
  • Casting Or Compression Moulding Of Plastics Or The Like (AREA)
  • Lining Or Joining Of Plastics Or The Like (AREA)
  • Shaping Of Tube Ends By Bending Or Straightening (AREA)
  • Manufacturing Of Steel Electrode Plates (AREA)

Abstract

The invention relates to a method for rolling a strip in a strip rolling mill which has at least two roll stands or an individual stand with upper and lower, optionally adjustable working rolls respectively, said rolls being optionally supported indirectly on support rolls or with intermediate rolls. At least one pass is rolled in said rolls in order to modify the state of the rolled strip. A target distribution of stresses or any target form of unevenness is predetermined for the rolled strip and compared with the actual distribution of stresses and the mechanical or physical control elements are employed in such a way as to minimise the difference between the predetermined and actual distribution of stresses as far as possible. In addition to the actual distribution of stresses in the hot strip, the distribution of temperature over the width of the strip is determined and used to calculate the distribution of stresses which would be present after the strip has cooled if the strip were free of stresses in the hot state with the distribution of temperature that exists behind the roll gap and this temperature-induced distribution of stresses is used to correct the actual stress before this is compared with the target form of unevenness.

Description

Planheitsregelung zur Erzielung von planem KaltbandFlatness control to achieve flat cold strip
Beschreibungdescription
Die Erfindung betrifft ein Verfahren zum Walzen eines Walzbandes in einer Bandstrasse mit zumindest zwei Walzgerüsten oder einem Einzelgerüst mit jeweils oberen und unteren ggf. einstellbaren Arbeitswalzen, die sich ggf. unmittelbar oder über Zwischenwalzen an Stützwalzen abstützen und in denen zur Zustandsanderung des Walzbandes mindestens ein Stich gewalzt wird, wobei für das Walzband eine Zielspannungsverteilung bzw. eine beliebige Zielunplanheitsform vorgegeben und mit der faktisch erreichten Spannungsverteilung verglichen wird, und zur Verfügung stehende mechanisch oder physikalisch wirksame Stellglieder in der Art eingesetzt werden, daß die Differenz zwischen vorgegebener und faktisch erreichter Spannungsverteilung möglichst weitgehend minimiert wird.The invention relates to a method for rolling a rolled strip in a strip mill with at least two roll stands or a single stand, each with upper and lower optionally adjustable work rolls, which are supported, if necessary, directly or via intermediate rolls on support rolls and in which at least one stitch is used to change the condition of the rolled strip is rolled, a target stress distribution or any target unevenness form is specified for the rolled strip and compared with the actually achieved stress distribution, and available mechanically or physically effective actuators are used in such a way that the difference between the predetermined and the actually achieved stress distribution is as large as possible is minimized.
Die Planheitsmessung von kaltgewalztem Band erfolgt gewöhnlich mittelsThe flatness measurement of cold rolled strip is usually done using
Planheitsmessrollen, welche die aktuelle Spannungsverteilung über die Bandbreite messen. Die Messung erfolgt üblicherweise auf der Auslaufseite des Walzgerüstes, wo mittlere Bandtemperaturen zwischen 80 und 160° C auftreten. Sinngemäß gilt das auch für andere Metalle wie Aluminium oder Kupfer.Flatness measuring rollers, which measure the current tension distribution over the bandwidth. The measurement is usually carried out on the outlet side of the roll stand, where average strip temperatures between 80 and 160 ° C occur. The same applies analogously to other metals such as aluminum or copper.
Erfahrungsgemäß treten zwischen Bandmitte und Bandkante Temperaturgradienten in der Größenordnung von 10° - 30°C auf. In Figur 1 sind dazu beispielhaft zwei beim Reversierwalzen von Edelstahl gemessene Bandtemperaturverteilungen aufgetragen. Geht man von dem thermischen Ausdehnungskoeffizienten von Stahl von etwa 1.2 10" 5 / Grad und einem Elastizitätsmodul von 210000 N/mm2 aus, so induziert einExperience has shown that temperature gradients of the order of 10 ° - 30 ° C occur between the strip center and the strip edge. In FIG. 1, two strip temperature distributions measured during the reversing rolling of stainless steel are plotted as an example. If one assumes the thermal expansion coefficient of steel of approximately 1.2 10 " 5 / degrees and an elastic modulus of 210,000 N / mm 2 , then induced
Temperaturunterschied von 10 Grad bereits eine Spannungsdifferenz von etwa 25 N/mm2 im kaltgewalzten Stahlband; angestrebt wird aber üblicherweise, die Spannungsunterschiede über der Bandbreite unter 20 N/mm2 zu halten. Ohne Planheitsregelung hätte diese temperaturinduzierte Spannung keinen Einfluß auf die Planheit des Endproduktes, dem abgekühlten Band, zumindest dann nicht, wenn sie im elastischen Bereich bleibt.Temperature difference of 10 degrees already a tension difference of about 25 N / mm 2 in the cold-rolled steel strip; However, the aim is usually to keep the voltage differences across the bandwidth below 20 N / mm 2 . Without Flatness control would have no influence on the flatness of the end product, the cooled strip, at least if the temperature-induced tension remains in the elastic range.
Mit der Planheitsregelung soll die Kontur des Walzspaltes so geregelt werden, daß dieWith the flatness control, the contour of the roll gap should be controlled so that the
Bandplanheit oder eine gezielte Unplanheitsform erhalten bleibt oder erzielt wird. Ein Problem besteht aber gerade darin, daß die Meßgröße die Spannungsverteilung im warmen Band ist, die mit der beschriebenen temperaturinduzierten Spannung (im obigen Beispiel mehr als 25 N/mm2) behaftet ist. Das heißt, die bekannte Planheitsregelung mit einer target flatness oder Zielfunktion für planes Band wird auch diese temperaturinduzierte Spannung im warmen Band ausregeln. Nach dem Auskühlung und Abklingen des Temperaturunterschiedes wird im abgekühlten Band der Zielunplanheitsform ein Spannungsanteil entsprechend der temperaturinduzierten Spannung jedoch mit umgekehrtem Vorzeichen zusätzlich überlagert.Band flatness or a specific form of flatness is retained or is achieved. One problem, however, is that the measured variable is the stress distribution in the warm band, which is associated with the temperature-induced stress described (in the example above, more than 25 N / mm 2 ). This means that the known flatness control with a target flatness or target function for flat strip will also regulate this temperature-induced tension in the warm strip. After the temperature difference has cooled and subsided, a voltage component corresponding to the temperature-induced voltage, but with the opposite sign, is additionally superimposed in the cooled band of the target unevenness form.
Die Ziel-Spannungsverteilungen oder Ziel-Unplanheitsformen könnten für ein gegebenes Produkt zusammen mit einer gegebenen Walz- bzw. speziellen Kühlstrategie im Prinzip auch so vorgegeben werden, daß man eine ausreichende Planheit des abgekühlten Produktes erhält. Allerdings ist die Suche nach den erforderlichen Zielfunktionen oder Unplanheitsformen ein aufwendiger empirischerThe target stress distributions or target non-flatness shapes could in principle also be specified for a given product together with a given rolling or special cooling strategy in such a way that the cooled product is sufficiently flat. However, the search for the required objective functions or non-flatness forms is a complex empirical one
Prozeß, der für jedes Produkt ein Abwickeln des Bundes mit Probenentnahme erforderlich macht.Process that requires the federal government to be unrolled and sampled for each product.
Technologisch zufriedenstellender wäre es, nicht mehr zwischen der meßbaren Planheit im warmen Zustand unmittelbar hinter dem Walzspalt und den für verschiedene Produkte und Walzstrategien verschiedenen Kaltunplanheitsformen der abgekühlten Bunde unterscheiden zu müssen.It would be technologically more satisfactory to no longer have to distinguish between the measurable flatness in the warm state immediately behind the roll gap and the different cold unevenness forms of the cooled coils for different products and rolling strategies.
In den Jahren 1973 und 1975 ist in Ermangelung einer damals noch nicht entwickelten direkten Messung der Bandspannung mittels Zugspannungsmessrollen und nachfolgender Regelung oder Messung der lokalen Bandlängung vorgeschlagen worden, die Bandtemperaturverteilung selber zu messen (DE-A-2 349 61 1 und DE-A-2 554 246). Unterschiede in der Bandtemperatur über der Breite werden dort in direkter Weise als Unterschied im Umformgrad über der Breite interpretiert und dieser Unterschied im Umformgrad wiederum als Ursache für Planheitsfehler. Indem nun die Temperaturunterschiede im Band in direkter Weise in Unterschiede der Kühlmittelbeaufschlagung auf die Walze umgerechnet werden, sollte die Walzenkontur und damit die lokalen Umformgrade verändert werden.In 1973 and 1975, in the absence of a direct measurement of the belt tension by means of tension measuring rollers, which had not yet been developed at the time, and subsequent regulation or measurement of the local belt elongation, it was proposed to measure the belt temperature distribution itself (DE-A-2 349 61 1 and DE-A- 2nd 554 246). Differences in strip temperature across the width are interpreted directly as a difference in the degree of deformation over the width, and this difference in the degree of deformation is in turn the cause of flatness errors. By now converting the temperature differences in the strip directly into differences in the coolant applied to the roll, the roll contour and thus the local degrees of deformation should be changed.
Dieses Verfahren ist mindestens deshalb unvollständig, weil Temperaturunterschiede nicht nur wegen unterschiedlicher Umformgrade auftreten, sondern auch andere Ursachen haben, wie thermische Walzenprofile, unterschiedlicheThis process is at least incomplete because temperature differences not only occur due to different degrees of deformation, but also have different causes, such as thermal roll profiles
Kühlschmiermittelfiüsse und das größere Verhältnis Oberfläche/Volumen an der Bandkante besonders im aufgewickelten Zustand, wodurch die Temperatur zur Bandkante hin üblicherweise abfällt. Dagegen ist der Umformgrad beim Walzen von dünnen Stahlbändern wegen der Einbettung des Walzgutes in die Walze üblicherweise an der Bandkante höher, und trotzdem ist die Temperatur an der Kante wegen der soeben beschriebenen Effekte in der Summe niedriger.Cooling lubricant flows and the larger surface area / volume ratio at the strip edge, especially when wound up, as a result of which the temperature usually drops towards the strip edge. In contrast, the degree of deformation when rolling thin steel strips is usually higher at the strip edge because of the embedding of the rolled material in the roller, and nevertheless the temperature at the edge is lower overall due to the effects just described.
Das in den Patentanmeldungen DE-A-2 349 61 1 und DE-A-2 554 246 beschriebene Verfahren hat sich demzufolge auch nicht durchgesetzt, sondern wurde später durch die beschriebene direkte Messung der Zugspannungsverteilung mit nachfolgenderThe method described in the patent applications DE-A-2 349 61 1 and DE-A-2 554 246 has therefore not become established either, but was later followed by the described direct measurement of the tension distribution with subsequent
Regelung ersetzt. Dabei ist eines der Stellglieder dieser Regelung weiterhin die lokale Steuerung der Kühlmittelmenge der Arbeitswalze, die üblicherweise den Restfehler minimieren soll, der von den anderen Stellgliedern wie Walzenbiegung, Verschiebung oder auch der aufblasbaren Walze nicht abgedeckt werden kann.Regulation replaced. One of the actuators of this regulation is still the local control of the amount of coolant in the work roll, which is usually intended to minimize the residual error that cannot be covered by the other actuators, such as roll bending, displacement or the inflatable roll.
In der Firmeπdruckschrift "ABB Automation and Drives (Dokument 3BSE005258) vom 17.02.94, Seite 3" ist der technische Stand der Planheitsregelung zu diesem Zeitpunkt wie folgt zusammengefaßt:In the company publication "ABB Automation and Drives (document 3BSE005258) dated February 17, 1994, page 3", the technical status of the flatness control at this time is summarized as follows:
1. Definition einer Ziel-Planheit1. Definition of target flatness
2. Messen der Band- Planheit2. Measure the flatness of the strip
3. Berechnung des Planheitsfehlers 4. Beschreibung der Funktion jedes mechanischen Walzspaltstellgliedes mittels Einflussfunktionen.3. Calculation of the flatness error 4. Description of the function of each mechanical roll gap actuator by means of influencing functions.
5. Bestmögliche Überlagerung der Einflussfunktionen um den Planheitsfehler zu eliminieren 6. Verwendung der Walzspaltstellglieder um den Walzspalt einzustellen5. Best possible superimposition of the influencing functions to eliminate the flatness error. 6. Use of the roll gap actuators to set the roll gap
7. Verwendung der lokal einstellbaren Walzenkühlung zur selektiven Einstellung des Walzspaltes durch thermisch hervorgerufene Arbeitswalzen- Durchmesseränderungen7. Use of the locally adjustable roll cooling for the selective setting of the roll gap by thermally induced work roll diameter changes
Diesen Stand der Technik findet man auch in der europäischen Patentanmeldung EPThis state of the art can also be found in the European patent application EP
0850704 A1 ergänzt durch den Hinweis, daß zur Erzielung eines in kaltem Zustand planen Bandes beim warmen Band über die Bandlängen unterschiedliche Unplanheitsformen vorgegeben werden. Keine Aussagen findet man beim Stand der Technik darüber, was die genaue Ursache eines im kalten Zustand unplanen Bandes ist, nämlich wie oben beschrieben, das dem technischen Stand entsprechende0850704 A1 supplemented by the note that in order to achieve a strip that is flat in the cold state, different flatness types are specified for the strip in the warm strip over the strip lengths. No statements can be found in the state of the art as to what the exact cause of a band which is unplanned in the cold state, namely, as described above, is that which corresponds to the technical state
Regelkonzept selbst, im Zusammenspiel mit inhomogenen Temperaturverteilungen über die Bandbreite. Ebenfalls keine Aussagen findet man darüber, was man neben bloßer Empirie ("im warmen Band unterschiedliche Unplanheitsformen") dagegen tun kann.Control concept itself, in interaction with inhomogeneous temperature distributions over the bandwidth. There are also no statements about what can be done about it besides mere empiricism ("different forms of unplannedness in the warm band").
Ziel der vorliegenden Erfindung ist es, ein Verfahren zur Planheitsregelung zu finden, mit dem nicht mehr zwischen der messbaren Planheit im warmen Zustand unmittelbar hinter dem Walzspalt und den für verschiedene Produkte und Walzstrategien verschiedenen Kaltunplanheitsformen der abgekühlten Bunde unterschieden werden muß und mit dem im warmen Zustand die gleichen Planheits- bzw Unplanheitsformen vorgegeben werden können.The aim of the present invention is to find a method for flatness control with which it is no longer necessary to distinguish between the measurable flatness in the warm state immediately behind the roll gap and the different cold uneveness forms of the cooled bundles for different products and rolling strategies, and with the warm state the same flatness or non-flatness shapes can be specified.
Zur Lösung der Aufgabe ist vorgesehen, daß neben der eigentlichen Spannungsverteilung im warmen Band auch die Bandtemperaturverteilung über die Bandbreite erfaßt und hieraus rechnerisch die Spannungsverteilung ermittelt wird, welche sich nach dem Abkühlen des Bandes einstellen würde, wenn das Band im warmen Zustand mit der hinter dem Walzspalt bestehenden Temperaturverteilung spannungsfrei wäre, und daß diese temperaturinduzierte Spannungverteilung zur Korrektur der faktisch erreichten Spannung benutzt wird, bevor diese mit der Zielunplanheitsform verglichen wird.To solve the problem, it is provided that in addition to the actual tension distribution in the hot strip, the strip temperature distribution over the strip width is also detected, and from this the tension distribution is calculated, which would occur after the strip had cooled down if the strip was in the warm state with the one behind Roll gap existing temperature distribution would be stress-free, and that this temperature-induced stress distribution is used to correct the actually achieved stress before it is compared with the target non-flatness form.
Der Vorteil dieses erfindungsgemäßen Vorschlages besteht darin, daß dieThe advantage of this proposal according to the invention is that the
Formulierung der Zielfunktion für die Planheit gezielt so erfolgen kann, daß auf direktem Wege eine bestmögliche Planheit des abgekühlten Bundes erreicht wird. Im Gegensatz zu der Absicht der DE-A-2 349 61 1 und DE-A-2 554 246 benutzt die Erfindung die Temperaturmessung nicht als eine direkt mit der Unplanheit verknüpfte Messgröße (diese Aufgabe übernimmt die Zugspannungsmessrolle), sondern entsprechend der technologischen Erkenntnisse der Unplanheitsursachen als eine ergänzende Korrekturgröße zur mittlerweile direkt meßbaren Zugspannung im warmen Band, so daß die Regelung in jedem Einzelfall gezielt abgekühltes Kaltband mit definierter Planheit erreichen kann.Formulation of the target function for flatness can be done in such a way that the best possible flatness of the cooled covenant is achieved directly. Contrary to the intentions of DE-A-2 349 61 1 and DE-A-2 554 246, the invention does not use the temperature measurement as a measurement variable directly linked to the unevenness (this task is performed by the tension measuring roller), but according to the technological knowledge of the Unplanarity causes as a supplementary correction quantity to the tensile stress in the hot strip, which can now be measured directly, so that the control can reach cold strip with a defined flatness in each individual case.
Ausgestaltungen des erfindungsgemäßen Verfahrens sind in den Unteransprüchen angegeben.Embodiments of the method according to the invention are specified in the subclaims.
Die Erfindung wird nachfolgend anhand der Zeichnungs- Figur 2 erläutert. Das Band wird in Laufrichtung rechnerisch in Streifen zerlegt, praktischerweise, aber nicht notwendigerweise mit einer Streifenbreite, wie sie von der verwendeten Zugspannungsmessrolle vorgeben ist. Diese beträgt in vielen technisch ausgeführten Fällen ca. 52 mm und entspricht in der Regel auch der Teilung der Düsen auf den Kühlbalken. Für jeden dieser Streifen i wird aus den Temperatursignalen eine mittlere Temperatur T ermittelt. Sind die Temperatursignale nicht in einer - im angegebenenThe invention is explained below with reference to the drawing Figure 2. The strip is computationally broken down into strips in the running direction, conveniently, but not necessarily with a strip width, as specified by the tension measuring roller used. In many technically executed cases this is approx. 52 mm and usually also corresponds to the division of the nozzles on the chilled beam. For each of these strips i, an average temperature T is determined from the temperature signals. If the temperature signals are not in one - in the specified
Beispiel - 52 mm Teilung gegeben, so muß vorher noch eine Interpolation auf diese Streifenteilung erfolgen. Außerdem wird eine mittlere Temperatur Tm über die gesamte Bandbreite errechnet. Auf der Auslaufseite wird die Differenz der Streifentemperaturen TA, von der mittleren Temperatur 7" Am mit ΔTA, bezeichnet ΔΓA, = rA, - rAm. (1 )Example - given a 52 mm division, an interpolation must first be made to this strip division. In addition, an average temperature T m is calculated over the entire bandwidth. On the outlet side, the difference between the strip temperatures T A and the mean temperature 7 " Am is denoted by ΔT A , ΔΓ A , = r A , - r Am . (1)
Indem die Werte ΔTA, mit dem thermischen Ausdehnungkoeffizienten des Walzgutes α auf der Auslaufseite multipliziert werden, erhält man eine gedachte relative Längenänderung Δ A, / Am dieser Streifen im Vergleich zur mittleren Länge Am aller dieser Streifen. Da diese Streifen aber zusammenhängend sind, können sie diese Längenänderung nicht einnehmen, sondern sie werden unter Spannung (annähernd) auf der Länge Am gehalten, welche die mittlere Bandtemperatur vorgibt. Diese streifenbezogeneBy multiplying the values ΔT A by the thermal expansion coefficient of the rolling stock α on the outlet side, an imaginary relative change in length Δ A , / Am is obtained this strip compared to the average length on all these strips. However, since these strips are connected, they cannot take up this change in length, but are kept under tension (approximately) at the length Am , which specifies the mean strip temperature. This stripe-related
Spannung σTA- beträgt dannStress σ TA - is then
Ojtsi = "^' Δ^"A' ^ ^-Am , (3) mit E als dem Elastizitätsmodul des Walzgutes.O j tsi = " ^ ^" A ' ^ ^ -Am, (3) with E as the elastic modulus of the rolling stock.
Das Vorzeichen ergibt sich aus der Konvention, daß Zugspannungen mit positivem und Druckspannungen mit negativem Vorzeichen versehen sind.The sign arises from the convention that tensile stresses have a positive and compressive stresses have a negative sign.
Werden jegliche Spannungsgradienten von den Stellgliedern im warmen Band ausgeregelt, so verbleibt im abgekühlten Band die Spannung σa If any tension gradients are corrected by the actuators in the warm band, the tension σ a remains in the cooled band
Bei temperaturunabhängigen Werkstoffwerten α und E ist dies der negative Ausdruck von (3): σ = E- Δ A// Am = E α Δ7" A/ . (4)For temperature-independent material values α and E, this is the negative expression of (3): σ = E- Δ A / / Am = E α Δ7 " A / . (4)
Die Formeln (2) bis (4) geben eine erste Näherung für die Umrechnung von derThe formulas (2) to (4) give a first approximation for the conversion from the
Temperaturverteilung auf die Spannungsverteilung an, denn:Temperature distribution to the voltage distribution, because:
• die Werkstoffwerte α und E sind nicht völlig temperaturunabhängig und• The material values α and E are not completely independent of temperature and
• die einzelnen Streifen werden nicht völlig auf die durch die mittlere Temperatur vorgegebene Länge m zurückgezogen, sondern verharren im Prinzip auf leicht unterschiedlichen Längen L, ≠Lm, was zu etwas verminderten Spannungen führt, als nach (4) berechnet wird.• The individual strips are not completely drawn back to the length m specified by the mean temperature, but in principle remain at slightly different lengths L, ≠ L m , which leads to somewhat reduced stresses than is calculated according to (4).
Um diese Längenkontour L, zu berechnen kann ein ähnliches Verfahren gewählt werden, wie es im Kapitel "Thermoelastic coupling" auf Seite 20 des Artikels Thermal camber model for hot and cold rolling für eine zylindrische Walze beschrieben wurde. Die dort resultierende Formel (26) für den zylindrischen Fall läßt erkennen, daß die radiale Ausdehnungskontur R(z) verschwindet, wenn R sehr groß wird. Analog verschwindet auch die longitudinale Bandlängenkontur L, in unserem Fall, wenn die Bandlänge m sehr groß wird, womit die Berechnung nach (1 )-(4) praktisch ausreichtIn order to calculate this length contour L, a method similar to that described in the chapter "Thermoelastic coupling" on page 20 of the article Thermal camber model for hot and cold rolling for a cylindrical roller can be selected. The resulting formula (26) for the cylindrical case shows that the radial expansion contour R (z) disappears when R becomes very large. Similarly, the longitudinal band length contour L disappears, in our case when the band length m becomes very large, which means that the calculation according to (1) - (4) is practically sufficient
Im Vergleich zu empirisch ermittelten Zielfunktionen, welche implizit einen thermisch induzierten Spannungsanteil enthalten können, hat das erfindungsgemäße Verfahren weitere Vorteile: Durch den Wegfall der Inspektion des abgekühlten Bundes ist die Ermittlung von Zielunplanheiten für das warme Band wesentlich vereinfacht. Streuungen der Kaltunplanheit aufgrund von Temperaturschwankungen werden vermieden. Unterschiede in den Zielunplanheiten für verschiedene Produkte werden vermindert.In comparison to empirically determined target functions, which can implicitly contain a thermally induced voltage component, the method according to the invention has further advantages: By eliminating the inspection of the cooled coil, the determination of target unevenness for the hot strip is considerably simplified. Scattered cold unevenness due to temperature fluctuations are avoided. Differences in target unevenness for different products are reduced.
Bei Anwendung der neuen Kühlstrategien für das Band brauchen die Zielunplanheiten nicht angepaßt zu werden. Bunde, die bisher im Kalteinsatz gewalzt werden und demzufolge nach jedem Stich größenordnungsmäßig einen Tag auskühlen, können nach kürzerer Zeit weiter gewalzt werden, sofern nicht die zulässige Gesamttemperatur überschritten wird. Auch hier gilt dann, daß durch das neueWhen using the new cooling strategies for the belt, the target unevenness need not be adjusted. Bundles that were previously rolled in cold operation and consequently cool down for one day after each pass can be rolled further after a shorter period of time, provided that the permissible total temperature is not exceeded. Then also here applies that through the new
Verfahren das Ziel Unplanheit von der Wartezeit zwischen den Stichen unabhängig wird. Procedure the goal becomes unplanned regardless of the waiting time between stitches.

Claims

Patentansprüche claims
1. Verfahren zum Walzen eines Walzbandes in einer Bandstrasse mit zumindest zwei Walzgerüsten oder einem Einzelgerüst mit jeweils oberen und unteren ggf. einstellbaren Arbeitswalzen, die sich ggf. unmittelbar oder über Zwischenwalzen an1. Method for rolling a rolled strip in a strip mill with at least two roll stands or a single stand with upper and lower optionally adjustable work rolls, which may be directly or via intermediate rolls
Stützwalzen abstützen und in denen zur Zustandsanderung des Walzbandes mindestens ein Stich gewalzt wird, wobei für das Walzband eine Zielspannungsverteilung bzw. eine beliebige Zielunplanheitsform vorgegeben und mit der faktisch erreichten Spannungsverteilung verglichen wird, und zur Verfügung stehende mechanisch oder physikalisch wirksame Stellglieder in der Art eingesetzt werden, daß die Differenz zwischen vorgegebener und faktisch erreichter Spannungsverteilung möglichst weitgehend minimiert wird, dadurch gekennzeichnet, daß neben der eigentlichen Spannungsverteilung im warmen Band auch die Bandtemperaturverteilung über die Bandbreite erfaßt und hieraus rechnerisch dieSupport the support rollers and in which at least one pass is rolled to change the state of the rolled strip, a target stress distribution or any target unevenness form being specified for the rolled strip and compared with the actually achieved stress distribution, and available mechanically or physically effective actuators of the type are used that the difference between the predetermined and the actually achieved tension distribution is minimized as much as possible, characterized in that, in addition to the actual tension distribution in the warm band, the band temperature distribution over the band width is also recorded and from this the calculation
Spannungsverteilung ermittelt wird, welche sich nach dem Abkühlen des Bandes einstellen würde, wenn das Band im warmen Zustand mit der hinter dem Walzspalt bestehenden Temperaturverteilung spannungsfrei wäre, und daß diese temperaturinduzierte Spannungverteilung zur Korrektur der faktisch erreichten Spannung benutzt wird, bevor diese mit der Zielunplanheitsform verglichen wird.Tension distribution is determined, which would occur after the strip had cooled, if the strip were tension-free in the warm state with the temperature distribution behind the roll gap, and that this temperature-induced tension distribution is used to correct the tension actually reached before comparing it with the target flatness shape becomes.
2. Verfahren nach Anspruch 1 dadurch gekennzeichnet, daß die temperaturinduzierte Spannungsverteilung von der faktischen Spannungsverteilung subtrahiert wird, die resultierende Spannungsverteilung mit der Zielunplanheitsform verglichen wird, daraus die Differenz errechnet und zur Verfügung stehende mechanisch oder physikalisch wirksame Stellglieder in der Art eingesetzt werden, daß die Differenz möglichst weitgehend minimiert wird. 2. The method according to claim 1, characterized in that the temperature-induced stress distribution is subtracted from the actual stress distribution, the resulting stress distribution is compared with the target non-flatness form, the difference is calculated therefrom and available mechanically or physically effective actuators are used in such a way that the Difference is minimized as much as possible.
3. Verfahren nach Anspruch 1 dadurch gekennzeichnet, daß die temperaturinduzierte Spannungsverteilung zu der Zielunplanheitsform addiert wird, die faktisch ermittelte Planheitsverteilung mit dieser Summenverteilung verglichen wird, daraus die Differenz errechnet und zur3. The method according to claim 1, characterized in that the temperature-induced stress distribution is added to the target non-flatness form, the factually determined flatness distribution is compared with this sum distribution, the difference is calculated from it and
Verfügung stehende mechanisch oder physikalisch wirksame Stellglieder in der Art eingesetzt werden, daß die Differenz möglichst weitgehend minimiert wird.Available mechanically or physically effective actuators are used in such a way that the difference is minimized as much as possible.
4. Verfahren nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß im Sinne eines technologischen Kompromisses mehrerer Gesichtspunkte der Planheitsreglung die temperaturinduzierte Spannungsverteilung vor der Weiterverarbeitung mit einem Verstärkungsfaktor multipliziert wird.4. The method according to any one of claims 1 to 3, characterized in that in the sense of a technological compromise of several aspects of flatness control, the temperature-induced stress distribution is multiplied by a gain factor before further processing.
5. Verfahren nach Anspruch 4, dadurch gekennzeichnet, daß im Sinne einer technologischen Profilgewichtung dieser Verstärkungsfaktor für jeden Bandstreifen einen unterschiedlichen Wert hat.5. The method according to claim 4, characterized in that in terms of a technological profile weighting, this gain factor has a different value for each strip.
6. Verfahren nach einem der Ansprüche 1 -5; dadurch gekennzeichnet, daß die Bandtemperaturverteilung hinter dem Walzspalt meßtechnisch, vorzugsweise berührungslos erfaßt wird.6. The method according to any one of claims 1 -5; characterized in that the strip temperature distribution behind the roll gap is recorded by measurement, preferably without contact.
7. Verfahren nach einem der Ansprüche 1-5; dadurch gekennzeichnet, daß die Bandtemperaturverteilung hinter dem Walzspalt aus einem Rechenmodell abgeleitet wird. 7. The method according to any one of claims 1-5; characterized in that the strip temperature distribution behind the roll gap is derived from a calculation model.
EP00929223A 1999-03-15 2000-03-14 Control of surface evenness for obtaining even cold strip Revoked EP1161313B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19912796A DE19912796A1 (en) 1999-03-15 1999-03-15 Flatness control to achieve flat cold strip
DE19912796 1999-03-15
PCT/DE2000/000831 WO2000054900A1 (en) 1999-03-15 2000-03-14 Control of surface evenness for obtaining even cold strip

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EP1161313A1 true EP1161313A1 (en) 2001-12-12
EP1161313B1 EP1161313B1 (en) 2002-11-27

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CN101362154B (en) * 2008-09-28 2010-06-23 东北大学 Device and method for measuring material-coil coil-diameter and strip-width in rolling strip
CN101507975B (en) * 2009-03-20 2012-01-04 燕山大学 Comprehensive treatment method of double-frame UCM finisher strip-steel surface color-deviation defect
CN101623707B (en) * 2009-08-05 2011-05-25 燕山大学 Plate-shape standard curve calculating method of continuous rolling machine
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CN105689405B (en) * 2016-01-28 2018-02-02 燕山大学 A kind of intelligent establishing method of the online target flatness of cold-strip
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ATE228401T1 (en) 2002-12-15
WO2000054900A1 (en) 2000-09-21
ES2182801T3 (en) 2003-03-16
AU4741600A (en) 2000-10-04
DE19912796A1 (en) 2000-10-12
CN1343146A (en) 2002-04-03
TR200102682T2 (en) 2002-04-22
JP2003504206A (en) 2003-02-04
DE50000828D1 (en) 2003-01-09
BR0009025A (en) 2001-12-26
KR20010112335A (en) 2001-12-20
EP1161313B1 (en) 2002-11-27

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