Classifications

• • 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
  • B21B37/28—Control of flatness or profile during rolling of strip, sheets or plates
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
  • B21B1/22—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length
  • B21B2001/225—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length by hot-rolling
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B38/00—Methods or devices for measuring, detecting or monitoring specially adapted for metal-rolling mills, e.g. position detection, inspection of the product
  • B21B38/02—Methods or devices for measuring, detecting or monitoring specially adapted for metal-rolling mills, e.g. position detection, inspection of the product for measuring flatness or profile of strips

Definitions

• the invention relates to a method according to the preamble of claim 1; one application is particularly suitable for operation in a hot rolling mill, e.g. in the finishing train, but is not limited to this.
• the invention relates to a control device according to the preamble of patent claim 10.
• the object is achieved by a method of the type mentioned at the outset, the visible flatness and an intrinsic flatness of the metal strip being taken into account when controlling the roll stands using a dent model.
• the buckling model creates a clear connection between the intrinsic and visible flatness of the metal strip. This makes it possible for the first time not only to make a presetting based on flatness measurements, but to use the visible flatness for precise control or regulation of the rolling process in progress.
• the visible flatness is advantageously determined in the form of a dent pattern.
• the dent pattern is easily comparable in terms of data technology and can be saved with relatively little effort.
• the dent pattern is advantageously three-dimensional.
• the buckling pattern of the metal strip it is advantageous to evaluate not only the relative length of individual tracks of the metal strip, but also at least one of the variables wavelength, amplitude and phase offset of the individual tracks.
• the buckling pattern can thus be recorded much more precisely.
• a multitrack laser measuring device is advantageously used to determine the buckling pattern, which enables inexpensive detection of the buckling pattern with sufficient precision.
• the visible flatness is advantageously measured topometrically. In this way, a flat detection of the strip surface structure and in particular the dent pattern is directly possible.
• values for the visible flatness are advantageously converted into values for the intrinsic flatness or values for intrinsic flatness translated into values for visible flatness.
• intrinsic strip flatnesses calculated and visible strip flatnesses measured at the exit of a rolling mill can be adapted to one another or verified using a material flow model.
• the flatness is translated online. This enables a particularly exact control or regulation of the strip flatness.
• the flatness is translated with the help of an online-capable approximation function.
• on-line computing time can be saved when translating between visible and intrinsic flatness.
• its buckling pattern is advantageously modeled by means of the buckling model by applying a fictitious temperature distribution in the transverse direction of the metal strip.
• the thermal expansion corresponding to this strip temperature distribution in the longitudinal direction, but not in the transverse direction, corresponds to a length distribution that can be assigned to the intrinsic flatness. In this way, only a segment of limited length has to be modeled and the model equations of the elastic plate deformations with large deflections with suitable boundary conditions can be set up at the segment edges.
• an intrinsic flatness of the metal strip - viewed in the material flow direction - is advantageously determined in front of a physical measuring location of the flatness.
• one or more flatness limit values are advantageously specified at freely selectable points within and / or after the rolling mill.
• the flatness limit values can relate to the intrinsic flatness and / or the visible flatness. Because plan limit values can be specified anywhere within or after the rolling mill, control accuracies for the rolling process can be significantly increased.
• control device for operating a rolling train for metal strip with at least one roll stand, in particular according to the previously described method, the control device having at least one control unit which is coupled to a buckling model.
• Advantageous designs of the control device are specified in the subclaims. The advantages of the control device result analogously to those of the method.
• 1 shows a multi-stand rolling mill for rolling metal strip and a control device assigned to the rolling mill
• a rolling mill for rolling a metal strip 1 is controlled by a control computer 2.
• the metal strip 1 can be, for example, a steel strip, an aluminum strip or a non-ferrous metal strip, in particular a copper strip.
• the rolling mill has at least two roll stands 3.
• the roll stands 3 have at least work rolls 4 and - as indicated in FIG. 1 for one of the roll stands 3 - generally also support rolls 5.
• the roll stands 3 could also have more rolls, for example axially displaceable intermediate rolls.
• the metal strip 1 runs through the rolling mill in its longitudinal direction x, the transverse direction y of the metal strip 1 being largely parallel to the axes of the work rolls 4.
• the rolling train shown in FIG. 1 is designed as a finishing train for hot rolling steel strip.
• the present invention is particularly suitable for use in a multi-stand finishing train for hot rolling steel strip, it is not limited to this, in particular the rolling mill could also be designed as a cold rolling mill (tandem mill) and / or for rolling a non-ferrous metal ( For example, aluminum, copper or another non-ferrous metal).
• the control device 2 has a control unit 11. This in turn has a module 10 for profile and flatness control, which is coupled to a material flow model 9.
• the control device 2 specifies scaffold controllers 6 setpoints for profile and flatness actuators (not shown in more detail). The scaffold controllers 6 then adjust the actuators in accordance with the specified target values.
• the input variables supplied to the control device 2 include, for example, pass schedule data such as an entry thickness of the metal strip 1 and a rolling force and a pass reduction for each roll stand 3.
• the input variables generally also include a final thickness, a target profile value, a target thickness contour profile and a target flatness profile of the metal strip 1 at the outlet of the rolling mill.
• the rolled metal strip 1 should be as flat as possible.
• the metal strip 1 has flatness errors, as are shown schematically and by way of example in FIGS. 2a, 2b and 2c. Flatness errors of the metal strip 1 can be measured at a location x2, as indicated in FIG. 1, for example by means of a multi-track laser measuring device 13.
• Figure 2a shows a central bulge of the metal strip 1.
• Figure 2b shows flatness errors at the edges of the metal strip 1.
• Figure 2c shows bulges of the metal strip 1, which occur repeatedly in the longitudinal direction x of the metal strip 1, in particular in two areas in the transverse direction y of the metal strip 1.
• the buckling of the metal strip 1 is caused in particular by internal stresses in the metal strip 1. Internal stresses in the metal strip 1 are also referred to as intrinsic strip flatness ip.
• FIG. 3 shows the division of a metal strip 1 into fictitious tracks Sl to Sn or into measurement tracks Sl ⁇ to Sm ⁇ . If the metal strip 1 were cut into narrow longitudinal strips or into tracks S1 to Sn, one could measure an uneven strip length distribution (the intrinsic strip length distribution), which is the cause of the internal stresses in the metal strip 1.
• the multi-track laser measuring device 13 detects the relative
• Length of the metal strip 1 per measurement track Sl x to Sm and preferably also determines quantities such as the wavelength, amplitude and / or the phase offset of the individual tracks Sl to Sm. It is crucial that the corresponding intrinsic or measured relative lengths do not match for corresponding fictitious tracks Sl to Sn and measurement tracks Sl to Sm.
• intrinsic strip flatness ip denotes, as stated above, the Band length distribution over the tracks Sl to Sn.
• the visible flatness vp results from the buckling behavior of the strip, which depends, among other things, on sizes such as the strip thickness, the strip width, the modulus of elasticity of the metal strip 1 and the total tension under which the metal strip 1 is located.
• the visible flatness vp is measured at a location x2 at the outlet of the rolling mill, in particular a finishing train, and fed to a buckling model 12.
• the measurement of the visible flatness vp takes place according to the invention in such a way that not only is the visible strip length distribution over the strip width in the transverse direction y the output variable of a measuring device, but the three-dimensional buckling pattern of the strip can be reconstructed from the measuring device output variables.
• the wavelength and phase offset for each track Sl ⁇ to Sm are output by the measuring device.
• a topometric band flatness measurement is preferably based on a strip projection method. Stripe patterns are projected onto the surface of the metal strip 1 and continuously recorded with the aid of a matrix camera.
• the intrinsic flatness ip is preferably calculated at a location xl between or after the roll stands 3, in particular between and / or after the roll stands 3 of a finishing train.
• the calculation is preferably carried out using a material flow model 9 (see FIG. 1), which is preferably part of a control unit 11.
• the intrinsic flatness ip calculated by the material flow model 9 can be compared with the measured visible flatness vp with the aid of the buckling model 12.
• a cold rolling mill would be fundamental it is also possible to measure the intrinsic flatness ip on the metal strip 1.
• the bulge model 12 creates a clear connection between intrinsic flatness ip and visible flatness vp, insofar as this is possible.
• intrinsic flatness ip cannot be inferred from the buckling behavior, since such a metal strip 1 generally does not bulge.
• the different flatnesses are preferably determined in the following order:
• the visible flatness vp which corresponds to the buckling behavior of the metal strip 1, is usually measured after a last rolling stand 3, for example at the outlet of a finishing train.
• the intrinsic flatness ip of the metal strip 1 at the measurement site of the visible flatness vp (cf. step 1) is determined by means of the dent model 12.
• the intrinsic flatness ip between the roll stands 3, that is to say for example within the finishing train, is determined by means of the material flow model 9. In this way, the intrinsic flatness - seen in the direction of material flow - can be determined in front of the physical measuring location of the flatness, here the intrinsic flatness.
• the relationship between an intrinsic flatness ip between the roll stands 3 and an intrinsic flatness ip after the last of the roll stands 3 is established via the material flow model 9.
• Input variables such as the strip thickness contours of the metal strip 1 and flatness profiles or flatnesses before and after passing through a roll stand 3 can be fed to the material flow model 9.
• the Mate The radial flow model 9 determines the intrinsic flatness profile of the metal strip 1 after passing through the roll stand 3 and a rolling force profile in the transverse direction y of the metal strip 1 and leads it to a roll deformation model (not shown in more detail).
• the roll deformation model which is not shown in detail, is preferably part of a control unit 11.
• the roll deformation model determines roll deformations and feeds them to a target value determiner, not shown, which, on the basis of the determined roller deformations and a contour-side contour profile of the metal strip 1, sets the target values for the profile and flatness actuators in determined each individual roll stand 3.
• the material flow model 9 and the profile and flatness control implemented in module 10 can be adapted to the measurement data of the visible flatness vp.
• Lower and upper bounds can be specified for the visible flatness vp or for the corresponding visible band unevenness, which can be translated into barriers for the intrinsic flatness ip or intrinsic flatness with the aid of the buckling model 12.
• the bulge model 12 calculates the buckling pattern of the metal strip 1 from the intrinsic flatness.
• the visible flatness can in turn be determined from the calculated buckling pattern. Inverse modeling is used for the reverse conclusion.
• the dent model 12 is preferably based on the theory of elastic plate deformations.
• the intrinsic flatness ip is modeled by applying a fictitious strip temperature distribution over the strip width, that is to say in the transverse direction y, which leads to thermal expansion in the longitudinal direction x of the metal strip 1, to be precise equal to the length distribution belonging to the intrinsic flatness ip.
• a band segment as shown in FIG. 5 with length a, width b and thickness h.
• the longitudinal direction x, transverse direction y and a perpendicular z Only a band segment with a length a of half or a whole base buckling length is modeled, with periodic boundary conditions at the head and foot ends of the band segment.
• the boundary conditions at the strip edges are the free edges.
• the model equations are partial differential equations as well as the associated boundary conditions, which can be solved, for example, using the finite difference method or the finite element method.
• the dent model 12 can be used directly online.
• an online-capable approximation function can be generated using an offline model, which is then used online for the buckling model 12.
• the measured deflections of the metal strip 1, which are attributable to the buckling of the metal strip 1, generally have a significantly larger order of magnitude than that Strip thickness h.
• their magnitude is significantly smaller than both the typical wavelength of the buckling behavior and the bandwidth b.
• the classic, linear theory of plate deformation only applies if the deflections are less than or equal to approximately 1/5 of the strip thickness h, a non-linear description of the plate warps must be used in the present case.
• T denotes the temperature in the metal strip 1 and ⁇ x or ⁇ y the coefficient of thermal expansion in the longitudinal or transverse direction (x or y).
• Equations (I) and (IV) form a system of two coupled, non-linear, partial differential equations. If suitable boundary conditions are used, such as free margins or periodic boundary conditions Head and foot ends of a band segment, equations (I) and (IV) can be solved numerically in an iterative manner.
• the invention relates to a method and a control device for operating a rolling mill for metal strip 1, which has at least one rolling stand 3, the intrinsic flatness ip of the metal strip 1 being determined at the outlet of the rolling mill.
• the visible flatness vp or the buckling behavior of the metal strip 1 at the outlet of the rolling mill or preferably to measure it and by means of to translate a dent model 12 into the intrinsic planning unit ip of the metal strip 1.
• the visible flatness can thus be used online with the aid of the dent model 12 to control the rolling stands of the rolling mill.
• the visible flatness vp according to the invention can preferably be better regulated online, with the aid of the buckling model 12.
• the bulge model 12 is online-capable and establishes a one-to-one relationship between the absolute intrinsic flatness ip of the rolled metal strip 1 and the actually measured visual defects of the metal strip 1, that is to say the visible flatness vp.
• the verification, adaptation and coordination of a material flow model 9 based on the intrinsic flatness or its corresponding profile and flatness control with respect to the actual measured values is made possible.

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

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• 2003
  • 2003-10-06 DE DE10346274A patent/DE10346274A1/de not_active Withdrawn
• 2004
  • 2004-10-06 JP JP2006530106A patent/JP2007507354A/ja active Pending
  • 2004-10-06 EP EP04790153A patent/EP1675694B1/fr not_active Expired - Fee Related
  • 2004-10-06 CN CNB2004800292220A patent/CN100395044C/zh not_active Expired - Fee Related
  • 2004-10-06 DE DE502004005723T patent/DE502004005723D1/de active Active
  • 2004-10-06 WO PCT/EP2004/011171 patent/WO2005035156A1/fr active IP Right Grant
  • 2004-10-06 AT AT04790153T patent/ATE380607T1/de active
  • 2004-10-06 US US10/574,723 patent/US20070006625A1/en not_active Abandoned

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