WO2023025669A1 - Procédé et dispositif de régulation d'une installation de coulée continue - Google Patents

Procédé et dispositif de régulation d'une installation de coulée continue Download PDF

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Publication number
WO2023025669A1
WO2023025669A1 PCT/EP2022/073152 EP2022073152W WO2023025669A1 WO 2023025669 A1 WO2023025669 A1 WO 2023025669A1 EP 2022073152 W EP2022073152 W EP 2022073152W WO 2023025669 A1 WO2023025669 A1 WO 2023025669A1
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WO
WIPO (PCT)
Prior art keywords
mold
roller
fluctuations
strand
rollers
Prior art date
Application number
PCT/EP2022/073152
Other languages
German (de)
English (en)
Inventor
Philipp Wieser
Veit Humer
Josef Watzinger
Original Assignee
Primetals Technologies Austria GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Primetals Technologies Austria GmbH filed Critical Primetals Technologies Austria GmbH
Priority to CN202280057896.XA priority Critical patent/CN117858775A/zh
Priority to KR1020247008365A priority patent/KR20240055000A/ko
Publication of WO2023025669A1 publication Critical patent/WO2023025669A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/16—Controlling or regulating processes or operations
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/12—Accessories for subsequent treating or working cast stock in situ
    • B22D11/128—Accessories for subsequent treating or working cast stock in situ for removing
    • B22D11/1282—Vertical casting and curving the cast stock to the horizontal
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/16—Controlling or regulating processes or operations
    • B22D11/166—Controlling or regulating processes or operations for mould oscillation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/16—Controlling or regulating processes or operations
    • B22D11/168—Controlling or regulating processes or operations for adjusting the mould size or mould taper
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/16—Controlling or regulating processes or operations
    • B22D11/18—Controlling or regulating processes or operations for pouring
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/16—Controlling or regulating processes or operations
    • B22D11/18—Controlling or regulating processes or operations for pouring
    • B22D11/181—Controlling or regulating processes or operations for pouring responsive to molten metal level or slag level
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/16—Controlling or regulating processes or operations
    • B22D11/20—Controlling or regulating processes or operations for removing cast stock
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/16—Controlling or regulating processes or operations
    • B22D11/20—Controlling or regulating processes or operations for removing cast stock
    • B22D11/201—Controlling or regulating processes or operations for removing cast stock responsive to molten metal level or slag level
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/16—Controlling or regulating processes or operations
    • B22D11/20—Controlling or regulating processes or operations for removing cast stock
    • B22D11/208—Controlling or regulating processes or operations for removing cast stock for aligning the guide rolls

Definitions

  • the present invention relates to a method for controlling a continuous casting plant
  • the continuous casting plant has a mold and a strand guide arranged downstream of the mold
  • the mutual distance between opposite rollers of the strand guide before the solidification point is changed cyclically, namely by cyclically changing the roller distance between opposite rollers of the strand guide in the opposite direction to the fluctuations in the meniscus
  • the invention also includes a corresponding device.
  • the method can be used in continuous casting.
  • the process can be advantageously used in all continuous casting processes with high casting speeds, because here a highly dynamic regulation/control of the liquid level is increasingly necessary.
  • continuous casting includes the casting of slabs and strips, in particular thin slab casting, such as thin slab casting in a direct connection, ie in connection with a continuous casting plant and a hot rolling plant.
  • the strand pumping occurs to a particular extent in continuous casting plants in which the roller spacing in the strand guide is constant over longer sections (i.e. several rollers that follow one another in the transport direction of the strand have the same distance from one another).
  • the roller spacing in the strand guide is constant over longer sections (i.e. several rollers that follow one another in the transport direction of the strand have the same distance from one another).
  • harmonic waves In addition to the fundamental wave, there are also harmonic waves. It was found that strand pumping only occurs above a critical casting speed that can be determined empirically, which in turn depends on the equipment used and the mode of operation. However, a limitation of the casting speed is unacceptable in view of a constant trend towards capacity increases. Typical casting speeds are, for example, up to 6 m/min and higher for thin slab casting in direct connection.
  • the strand pumping leads to an irregular thickness of the strand shell, which can be problematic, especially in thin slab casting in direct composite due to the lower thickness of the cast strand compared to a cast slab and the high casting speed.
  • WO 2018/108652 A1 therefore proposes a method mentioned at the outset, in which fluctuations in the liquid level are reduced both by cyclically counter-rotating movements of the inflow device - with a relatively low frequency - and by cyclically counter-rotating changes in the roller spacing of rollers of the strand guide - with a relatively high frequency become. It has been found that with the compensation value determined for the roller spacing of the rollers of the strand guide, if this compensation value is fed to the adjustment device of the rollers, the full extent of the expected reduction in the fluctuations in the liquid level often cannot be achieved.
  • the continuous casting plant has a mold and a strand guide arranged downstream of the mold
  • the mutual distance between opposite rollers of the strand guide before the solidification point is changed cyclically, namely by cyclically changing the roller distance between opposite rollers of the strand guide in the opposite direction to the fluctuations in the meniscus
  • the actual value of the roller spacing is used as one of the input variables for this observer in order to compensate for a phase shift and/or amplitude of the actual value of the roller spacing.
  • a movement that compensates for the fluctuations is thus brought about by the calculation rule by means of the employed rollers of the strand guide.
  • the mutual distance between opposite rollers, between which the strand is guided, has a direct effect on the liquid core of the strand and directly changes the meniscus, the fluctuations in the meniscus are corrected immediately. This enables more precise and dynamic control of the liquid level. Smaller fluctuations in the meniscus bring about an improvement in the quality of the strand or the slab end product, such as a reduction in inclusions or the avoidance of cracks.
  • in-phase vibrations with higher frequencies can be generated by changing the roller spacing.
  • the movement of the inflow device which determines the amount of liquid metal that gets into the mold, is transferred more slowly to the meniscus, because liquid metal that is still below the inflow device flows into the mold when the position of the inflow device is changed.
  • the position of the inflow device can only be changed in phase at lower frequencies with the inflow device, or only a lower controller quality can be achieved as a result of this additional, non-compensable dynamic.
  • a control or regulation of the liquid level can be achieved by changing the mutual distance between opposite rollers.
  • the strand lies between opposite rollers.
  • the process only requires adjustable rollers, which are arranged in front of the solidification point.
  • the complete solidification point is the point where the core of the strand or slab is already solid, seen along the strand guide.
  • regulation or control of the meniscus is only possible before solidification, i.e. there where the core of the strand or slab is still liquid.
  • the rollers whose mutual distance is changed to reduce the fluctuations in the meniscus can, but do not have to, be the rollers that are driven in order to pull the metal strand out of the mold.
  • the mutual distance between opposite rollers of the strand guide is changed cyclically.
  • “Cyclically changed” means that opposite rollers periodically change their mutual distance to each other.
  • the method according to the invention can be used as the only regulation or control method for the liquid level (in combination with the flow regulation of the inflow device), or also in combination with other regulation or control methods for the liquid level through the inflow device.
  • control and Control methods the individual regulation or control methods can be operated independently of one another.
  • the cyclic changes can be in a frequency range of up to greater than or equal to 0.6 Hz, preferably up to 5 Hz.
  • the change in the roller spacing can therefore take place with frequencies that are also greater than or equal to 0.6 Hz, which are in particular up to 5 Hz.
  • the other method or methods could cover a lower frequency range (e.g. from 0 to 0, 6 Hz), while the inventive method only the higher frequency range (e.g. from 0.6 to 1 Hz, from 0.6 to 2 Hz, from 0.6 to 3 Hz, from 0.6 to 4 Hz or from 0.6 to 5 Hz).
  • roller segment each with one or more rollers, are arranged along the strand guide on both sides (i.e. opposite one another with regard to the strand), with at least one roller segment being adjusted normal to the strand guiding direction.
  • roller segment also includes so-called grids (- 'grids') which are typically arranged directly below the mould.
  • “normal to the strand-guiding direction” means any adjustment that runs essentially normal to the strand-guiding direction. This includes both pivoting and parallel displacement of a roller segment.
  • the strand guide is usually divided into several segments along the strand guiding direction, each segment contains two opposite roller segments.
  • a roller segment arranged near the mold is advantageously adjusted.
  • at least one roller segment of the first segment is adjusted.
  • the high gain from the actuator, which intervenes directly, enables maximum dynamics.
  • the factor relating to the change in the roller spacing in the top segment and its influence on the liquid level is typically around 1:10 to 1:13 (swivel segments) or 1:20 (parallel moving segments). This means that an increase in the distance between the rollers of 0.1 mm causes the liquid level in the mold to drop by 1 mm to 1.3 mm or 2 mm.
  • only small changes in the roller spacing are required, which can be accomplished in a very short time in order to be able to compensate for high frequencies of the strand pumping of up to 5 Hz.
  • At least one roller segment is pivoted.
  • the pivot axis is preferably closer to the mold, so that the one further away from the mold Part of the roller segment is deflected more.
  • the outer roller segment ie the one on the outwardly curved side of the strand guide, could be fixed, for example realized by a fixed outer frame.
  • the opposite roller segment i.e. the one on the inwardly curved side of the strand guide, is pivoted.
  • it has, for example, an inner frame which carries the rollers and which is pivotably mounted.
  • the inner roller segment to be attached in a fixed manner and for the outer roller segment to be pivoted relative to the inner roller segment.
  • roller segments each with one or more rollers, are arranged on both sides along the strand guide, with at least the inner roller segment closest to the mold being perpendicular to the strand guide direction about the axis of rotation of a roller of this roller segment, the the mold is closest, is pivoted. Due to the small distance to the mold, the pivoting of the top roller segment has a particularly rapid effect on the liquid level.
  • At least one roller segment is adjusted in a parallel alignment to an opposite roller segment arranged along the strand guide, which in turn enables selective adjustment of the roller spacing between individual roller segments and rollers.
  • the outer roller segment ie the one on the outwardly curved side of the strand guide
  • the opposite roller segment ie the one on the inwardly curved side of the strand guide
  • the distance between the rollers of two opposite roller segments allows the volume of liquid metal in the core of the strand to be determined and a conclusion to be drawn as to a relative change in the meniscus.
  • At least one roller segment is adjusted by an adjustment device which includes at least one hydraulic or electromechanical actuator (eg hydraulic cylinder or electric spindle drive).
  • at least one hydraulic or electromechanical actuator eg hydraulic cylinder or electric spindle drive.
  • a proportional valve is preferably used for at least one hydraulic cylinder.
  • An embodiment of the invention provides that frequencies of the fluctuations in the mold level are detected in a frequency range from 0 to 5 Hz and the fluctuations are compensated for by means of cyclically counter-rotating change in the roller spacing of rollers of the strand guide. In this embodiment variant, there is no compensation for the fluctuations in the liquid level by the inflow device for the mold.
  • a second observer determines a second compensation value for a target value of the roller spacing of the rollers of the strand guide on the basis of frequencies in the second frequency range, the actual value of the roller spacing being used as one of the input variables for this second observer.
  • This variant has the advantage that low-frequency fluctuations in the liquid level can be compensated for by controlling the inflow device of the mold, as has been the case in the prior art, while only the higher-frequency fluctuations in the liquid level are compensated for by controlling the distance between the rollers. It is therefore possible to retrofit existing controls for the low-frequency fluctuations with an additional control of the distance between the rollers.
  • control for the inflow device and/or the control for the roller spacing can be implemented with the aid of a so-called observer, as is shown in AT 518461 A1.
  • an observer is a system that consists of known input variables (e.g. manipulated variables or measurable disturbance variables) and output variables (measured variables) of an observed reference system non-measurable variables (states) reconstructed. To do this, it reproduces the observed reference system as a model and uses a controller to track the measurable, and therefore comparable, state variables. This prevents a model from generating an error that grows over time.
  • the variant of the method with two frequency ranges preferably has a first observer who determines a first compensation value for a target position of the inflow device based on frequencies in the first frequency range, and a second observer who determines a second compensation value for a target value for the roller spacing of the rollers of the strand guide determined from frequencies of the second frequency range, with the actual value of the roller spacing being used as one of the input variables for this second observer according to the invention.
  • the liquid level in the mold is regulated both by the inflow into the mold and by the guidance of the Meta II strand, preferably in the uppermost segment, after the mold. It is also advantageous that due to the separation of the observers on different actuators (on the one hand the first compensation value for the target position of the inflow device in the case of the first observer and on the other hand the second compensation value for the roller spacing of the rollers of the strand guide), there is no interference between the observers or no negative Observers can influence each other.
  • the first observer works in a frequency range of less than or equal to 0.6 Hz and the second observer in a frequency range of greater than or equal to 0.6 Hz, preferably between 0.6 and 5 Hz.
  • the separate frequency ranges of the two observers result in the advantage that there cannot be any interference between the observers due to overlapping of the frequency windows, which means, for example, that the setpoint for the actuator of the mold level control remains the same (in the case of no curvature) or smaller than in the case without secondary compensation.
  • fluctuations in the mold level are additionally reduced and losses in quality of the steel product are greatly reduced.
  • a possible device for carrying out the method according to the invention includes
  • Means for introducing molten metal into a mold, a strand guide comprising rollers and a measuring device for measuring fluctuations in the liquid level which is connected to a control device.
  • An adjusting device connected to the control device is provided, which is designed to reduce, in particular to compensate for, fluctuations in the liquid level due to cyclical changes in the roller spacing of opposite rollers of the strand guide that counteract the fluctuations in the liquid level, with the control device comprising at least one observer who is designed in such a way that, based on the frequencies of the fluctuations in the liquid level, a compensation value for a target value of the roller spacing of the rollers is determined and the actual value of the roller spacing is used as one of the input variables for this observer in order to determine a phase shift and/or amplitude of the actual value of the roller spacing compensate.
  • the adjustment device is designed for cyclic changes in the roller spacing in a frequency range of up to greater than or equal to 0.6 Hz, preferably up to 5 Hz.
  • the adjustment device can include at least one hydraulic or electromechanical actuator, such as a hydraulic cylinder or an electric spindle drive.
  • the adjusting device can be designed for cyclic changes in the roller spacing in a frequency range from 0 Hz, preferably up to 5 Hz, for example with hydraulic or electromechanical actuators such as a hydraulic cylinder or an electric spindle drive.
  • roller segments each with one or more rollers, are arranged on both sides along the strand guide, with at least one roller segment being adjustable by means of the adjusting device normal to the strand guide direction.
  • At least one roller segment can be adjustable in the top, ie first, segment. At least one roller segment can be pivotable. Or at least one roller segment can be adjusted in a parallel orientation to an opposite roller segment arranged along the strand guide.
  • a variant of the device according to the invention provides that the measuring device can be used to detect frequencies of the fluctuations in the mold level in a first frequency range and that these fluctuations can be compensated for by means of cyclically counter-rotating movements of an inflow device of the mold, and that further frequencies can be detected by means of the measuring device the fluctuations in the liquid level can be detected in a second frequency range and these fluctuations can be compensated for by means of the adjustment device by means of cyclically counter-rotating change in the roller spacing of rollers of the strand guide, the second frequency range being above the first frequency range.
  • the second observer has the same components as the first observer and works in the same way, with the difference that it specifies a second compensation value, not for the inflow device for the mold, but for the adjustment device, which is located in - preferably the top segment - of the strand guide located.
  • the method according to the invention and the device according to the invention can be applied to existing continuous casting plants with the above-mentioned requirements and represents a significant improvement in the quality of continuously cast steel at a significantly higher casting speed and thus increased productivity.
  • This new type of mold level control enables highly dynamic Effects, e.g. highly dynamic strand pumping with frequencies above 0.6 Hz, must also be suppressed when unforeseen operating conditions occur, such as wear or deformation of the adjustment device for the rollers, or unwanted changes in the strand thickness or the steel properties.
  • Fig. 1 is a schematic view of a portion of an inventive
  • Fig. 3 shows the schematic structure of a control device of the prior art
  • Fig. 4 details of the first observer from Fig. 3,
  • FIG. 5 schematically shows a control circuit according to the invention comprising a first and second observer
  • Fig. 6 shows the time course of various variables in the control of a
  • Fig. 7 shows the time course of roller spacing and liquid level when the
  • Fig. 8 shows the time course of roller spacing and liquid level when the
  • Roller spacing keeps the liquid level ideally constant
  • Fig. 9 shows the time course of roller spacing and liquid level when the
  • a continuous casting plant has a mold 1 .
  • Liquid metal 3 for example liquid steel or liquid aluminum, is poured into the mold 1 via a dip tube 2 .
  • the inflow of the liquid metal 3 into the mold 1 is adjusted by means of an inflow device 4 .
  • 1 shows an embodiment of the inflow device 4 as a sealing plug.
  • a position p of the inflow device 4 corresponds to a lifted position of the sealing plug.
  • the inflow device 4 can be designed as a slide.
  • the locking position p corresponds to the slide position.
  • the liquid metal 3 in the mold is cooled by means of cooling devices (not shown) so that it solidifies on the walls 1a of the mold 1 and a strand shell is thus formed.
  • a core 6 is still liquid. He only freezes later.
  • the strand shell 5 and the core 6 together form a metal strand 7.
  • the metal strand 7 is supported by a strand guide 8 and withdrawn from the mold 9.
  • the strand guide 8 is downstream of the mold 1 . It has several roller segments 8a on, which in turn have roles 8b. Only a few of the roller segments 8a and the rollers 8b are shown in FIG.
  • the metal strand 7 is pulled out of the mold 1 at a pull-off speed v by means of the rollers 8b.
  • the liquid metal 3 forms a liquid level 9 in the mold 1.
  • the liquid level 9 should be kept as constant as possible. Therefore - both in the prior art and in the present embodiment of the invention - the position p of the inflow device 4 is tracked in order to adjust the inflow of the liquid metal 3 into the mold 1 accordingly.
  • a height h of the liquid level 9 is recorded by means of a measuring device 10 (known per se).
  • the height h is supplied to a control device 11 for the continuous casting plant.
  • the control device 11 determines a manipulated variable S for the inflow device 4 according to a control method, which is explained in more detail below.
  • the inflow device 4 is then activated accordingly by the control device 11 .
  • the control device 11 outputs the manipulated variable S to an adjustment device 12 for the inflow device 4 .
  • the roller spacing which corresponds to the strand thickness d shown, can be adjusted in a targeted manner. As shown here in FIG. 1, this can be done in that at least one roller segment 8a has a fixed outer frame in the first segment, here, for example, the roller segment 8a located directly below the mold 1 on the left.
  • the opposite roller segment 8a, or the inner frame carrying this, can be pivoted about a pivot axis 23 which runs normal to the plane of the drawing.
  • the pivot axis 23 can coincide with an axis of rotation of a roller 8b, here with the axis of rotation of the upper roller 8b, but could of course also be provided at a different point.
  • the upper left roller segment 8a i.e. its outer frame
  • the upper right roller segment 8a i.e. its inner frame
  • the roller spacing of all pairs of rollers changes by the same amount. This could also be done with one or more hydraulic cylinders (distributed along the strand width and/or along the strand guiding direction).
  • each roller segment 8a has three rollers 8b on each side. However, there could also be only two or more than three rollers 8b per roller segment 8a.
  • the solid strand shell 5 and the liquid core 6 of the strand up to the solidification point D are shown here.
  • adjustment devices 24 are also provided in all segments 8a up to the point D of solidification. The adjusting devices 24 can each adjust the roller segments 8a by pivoting or by parallel displacement, as already explained in FIG.
  • the inner roller segment 8a of the first (top) segment is adjusted by pivoting about the pivot axis 23, the inner roller segment 8a of the second segment by parallel displacement using two adjustment devices 24.
  • the connection of the adjustment devices 24 to the control device 11 is not shown here.
  • the control device 11 implements—see FIG. 3—among other things a mold level controller 13 .
  • the mold level controller 13 is supplied with the height h of the mold level 9 .
  • a target value h* for the height h of the liquid level 9 is also supplied to the liquid level controller 13 .
  • the mold level controller 13 continues to be supplied with further signals.
  • the other signals can be, for example, the width and the thickness of the cast metal strand 7 (or more generally the cross section of the metal strand 7), the withdrawal speed v (or its desired value), 1 and others.
  • the mold level controller 13 uses the deviation of the height h of the mold level 9 from the setpoint h* to determine, in particular, a provisional setpoint position p'* for the inflow device 4.
  • the mold level controller 13 can use the other signals for its parameterization and/or for determining a pilot control signal pV .
  • the control device 11 also implements a first observer 14.
  • the first observer 14 is supplied with the height h of the liquid level 9 and its desired value h*, the further signals and a final desired position p* for the inflow device 4.
  • the first observer 14 determines a first compensation value k.
  • the first compensation value k is applied to the provisional desired position p'* and the final desired position p* is thus determined.
  • the manipulated variable S with which the inflow device 4 is controlled, is then determined on the basis of the deviation of the actual position p from the final setpoint position p*.
  • the control device 11 implements a subordinate position controller (not shown) for this purpose.
  • first and second observers 14 , 25 are not persons, but function blocks implemented in the control device 11 .
  • the difference between the provisional target position p'* and the final target position p* corresponds to the first compensation value k ascertained by the first observer 14 . Since the first compensation value k is determined by the first observer 14 and is therefore known to the first observer 14, the first observer 14 can also be supplied with the provisional desired position p'* as an alternative to the final desired position p*. Because of the fact that the first compensation value k is known to the first observer 14, the first observer 14 can easily determine the final desired position p* from the provisional desired position p'*.
  • a tapping point 15 at which the (provisional or final) target position p′*, p* is tapped can therefore be located before or after a node 16 as required, at which the first compensation value k is applied to the provisional target position p′*.
  • the tapping point 15 should be in front of a node 16', at which the pilot control signal pV is applied.
  • the first observer 14 has a determination block 17 .
  • the determination block 17 is supplied with the height h of the liquid level 9, the further signals and the final target position p*.
  • the determination block 17 has a model of the continuous caster. Using the model, the determination block 17 uses the additional signals and the final target position p* to determine an expected (i.e. model-based) calculation for the meniscus 9.
  • the determination block 17 uses the expected height, determines an expected (ie model-based) fluctuation value öh for the Height h of the liquid level 9, that is, the short-term fluctuation.
  • the determination block 17 can average the height h of the meniscus 9 and subtract the resulting mean value from the expected height.
  • the determined fluctuation value öh thus reflects the expected fluctuation in height h des Liquid level 9 reflected.
  • the determination block 17 uses the fluctuation value öh to determine the first compensation value k.
  • the procedure explained so far in connection with FIG. 3 corresponds to the procedure of the prior art. It is also used in this embodiment variant of the present invention.
  • the first observer 14 with the determination block 17 is shown again in FIG. In the context of the present invention, however, the determination block 17 as shown in FIG.
  • the first analysis element 18 is supplied with the fluctuation value öh. From this, the first analysis element 18 determines the frequency components of the fluctuation value öh.
  • a second analysis element 19 is preferably also present.
  • An additional signal Z is fed to the second analysis element 19 . From this, the second analysis element 19 determines the frequency components of the additional signal Z.
  • the additional signal Z can be a pull-out force F, with which the metal strand 7 is pulled out of the mold 1 by the rollers 8b of the strand guide 8 .
  • the extraction force F is directed parallel to the extraction speed v.
  • it can be the take-off speed v itself.
  • a force signal F′ for example, as the additional signal Z, with which (at least) one of the roller segments 8a of the strand guide 8 is acted upon.
  • the direction to which the force signal F' is related is orthogonal to the pull-off speed v.
  • the additional signal Z can be a local strand thickness d, which is measured by a measuring device 21 (see FIG. 1) in the strand guide 8 .
  • the first analysis element 18 feeds the frequency components determined by it to a selection element 22 . If present, this also applies analogously to the second analysis element 19.
  • the selection element 22 determines the associated wavelengths in conjunction with the take-off speed v, which correspond to the frequency components of the fluctuation value öh and possibly also of the additional signal Z. For this purpose, the take-off speed v is supplied to the first observer 14 and within the first observer 14 to the selection element 22 .
  • the selection element 22 determines the wavelengths at which the associated frequency component of the fluctuation value öh, possibly also the associated frequency component of the additional signal Z, is above a threshold value S1, S2.
  • the determination block 17 carries out a filtering of the height h of the meniscus 9 and the final target position p* for the wavelengths Ai selected by the selection element 22.
  • the determination block 17 determines the first compensation value k solely on the basis of the filtered height h of the liquid level 9 and the filtered final desired position p*.
  • the determination block 17 disregards the other frequency components of the height h of the liquid level 9 and the final target position p* in the context of determining the first compensation value k.
  • predetermined wave ranges can be specified for the selection element 22 . In this case, the predetermined wavebands represent an additional selection criterion.
  • wavelengths for which the associated frequency component of the fluctuation value öh, if applicable, the associated frequency component of the additional signal Z is above the respective threshold value S1, S2 are only selected if they are also within a of the predetermined wavelength ranges. Otherwise, they are not selected even if the associated frequency component of the fluctuation value öh, possibly also the associated frequency component of the additional signal Z, is above the respective threshold value S1, S2.
  • the second observer 25 has identical components to the first observer 14, analyzes frequencies of the strand pumping after the mold 1 and specifies a second compensation value k′ for the adjustment device 24, namely the compensation value for the setpoint SET of the roller spacing.
  • This target value SET is a static target value that usually corresponds to the desired strand thickness.
  • FIG. 5 shows a control circuit that includes a first and a second observer 14 , 25 .
  • the first observer 14 specifies a first compensation value k for the inflow device 4 of the mold 1, as a result of which the liquid level 9 in the mold 1 is regulated.
  • the first observer 14 and the inflow device 4 of the mold 1 together represent a standard system for controlling the liquid level 9 of the mold 1, which is used to compensate for frequencies in the first frequency range and thus represents a controller 27 for frequencies of the first frequency range.
  • This second compensation value k′ is supplied to the controller 28 for the roller adjustment, which calculates a control signal 29 for the roller distance from a set value SET and an actual value ACT and forwards this control signal 29 to the adjusting device 24 .
  • the actual value ACT is now also sent to the second observer 25, which takes it into account when calculating the second compensation value k′.
  • a single control method could also be provided that only controls or regulates the adjusting device 24 of the rollers 8b, while the inflow device 4 of the mold 1 is not used at all to compensate for the fluctuations in the liquid level.
  • the second observer 25 could be this only control method. In this case, the second observer 25 would generally cover a larger frequency range than with two control methods. This frequency range could then, for example, cover the frequencies from 0 to 0.6 Hz, from 0 to 1 Hz, from 0 to 2 Hz, from 0 to 3 Hz, from 0 to 4 Hz or from 0 to 5 Hz.
  • Fig. 6 shows an example of suppression of cyclic vibrations.
  • the time t is plotted along the horizontal axis.
  • the first (top) representation shows the position of the inflow device 4, labeled "Pos (4)”
  • the second figure shows the height of the liquid level 9 in the mold 1, labeled "M_L”
  • the third figure shows the flow of steel in the strand, labeled "St_FI”.
  • the first three illustrations clearly show that the position of the inflow device 4 changes cyclically, as does the height of the liquid level 9 and consequently also the flow of steel from the mold 1.
  • the control is activated, here by changing the position "Pos (4)" of the inflow device 4, the cyclical fluctuations in the mold level "M_L" are reduced.
  • the mutual distance between the rollers 8b in the uppermost segment would be changed cyclically in addition or as an alternative to changing the position “Pos (4)” of the inflow device 4 in order to reduce the fluctuations in the liquid level.
  • the upper figure shows the course of the liquid level 9 over time, the liquid level 9 ideally following the horizontal center line.
  • the figure below shows the course of the actual value ACT of the roller distance with the dotted line, with the dashed line the chronological progression of the roller spacing EST precalculated with the model of the observer and with the continuous line the chronological progression of the desired value SET of the roller spacing corrected with the second compensation value k'.
  • the target value SET of the roll spacing essentially corresponds to the desired strand thickness d.
  • the second compensation value k' is added to this and the resulting signal can then be used as the control signal 29 for the roller spacing.
  • the target value SET of the roller spacing is thus a static value which is reduced and increased by the second compensation value k' which changes, as a rule periodically, and consequently also as a rule periodically.
  • the signal that results from the application of the second compensation value k' to the static desired value SET is thus the final desired value, so to speak.
  • Fig. 7 shows the chronological progression of the roller spacing and liquid level 9 when the roller spacing is not changed.
  • the liquid level 9 changes its height periodically when the actual value ACT of the roller spacing, the precalculated roller spacing EST and the final target value of the roller spacing remain constant, i.e. in particular no second compensation value k′ is applied to the static target value SET.
  • the adjusting device 24 does not change the roller setting here.
  • the second compensation value k' which is applied to the target value SET of the roller spacing, must be changed with the same frequency as the uncontrolled liquid level 9 (Fig. 7) and usually with a corresponding phase shift to the liquid level 9, which results in a common
  • the course of the precalculated roller distance EST and the actual value ACT of the roller distance results in which common course has the same frequency as the desired value SET plus the second compensation value k', but is only phase-shifted with respect to the desired value SET plus the second compensation value k'.
  • the actual roll adjustment thus corresponds to the pre-calculated roll distance EST.
  • FIG. 9 shows the roll spacing and liquid level as a function of time when the actual roll spacing shows an unusual behavior. Despite control based on the setpoint SET plus the second compensation value k', there is a periodic fluctuation in the liquid level 9. This means everything is done as before in FIG. 8, but the result is different because the rollers 8b behave unexpectedly . Therefore, FIG. 9 shows both a difference in the phase and in the amplitude between the actual value ACT of the roller spacing and the predicted roller spacing EST.
  • FIG. 10 shows the chronological progression of the roller spacing and liquid level when the unusual behavior of the roller spacing from FIG. 9 is ideally compensated.
  • the latter can adapt the second compensation value k' in such a way that this unusual behavior is also compensated for. It can be seen that for this purpose the phase of the desired value SET plus the second compensation value k' has to be shifted in relation to FIG. 9 so that the liquid level 9 is ideally balanced again.
  • Typical strand thicknesses d in thin slab casting are around 100mm, typical casting speeds are between 2 and 6 m/min.
  • the roll pitch which is constant over longer sections of the strand guide in the direction of transport, is typically in the range of around 200 mm.
  • the frequencies of the fundamental wave and the harmonics of the oscillations of the meniscus then result from the casting speed and the roll spacing, which are to be compensated for with the method according to the invention and the device according to the invention.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)

Abstract

L'invention concerne un procédé de régulation d'une installation de coulée continue, l'installation de coulée continue comprenant une lingotière (1) et un corset de guidage (8) monté en aval de la lingotière (1) ; - dans la lingotière (1), du métal liquide (3) est coulé notamment par l'intermédiaire d'un dispositif d'alimentation (4) ; - la barre métallique (7) étant extraite de la lingotière (1) à l'aide de rouleaux (8b) mutuellement espacés du corset de guidage (8) ; - une grandeur de mesure étant déterminée, laquelle est en corrélation avec la variation du niveau de coulée se formant dans la lingotière, cette grandeur de mesure étant traitée par intégration d'au moins une règle de calcul et étant prise en compte pour réduire les variations du niveau de coulée (9), - afin de réduire les variations du niveau de coulée, l'espacement entre les rouleaux (8b) opposés du corset de guidage étant modifié cycliquement, notamment par une modification, cyclinque, opposée aux variations du niveau de coulée (9), de l'espacement entre rouleaux de rouleaux (8b) mutuellement opposés du corset de guidage (8), - les fréquences des variations du niveau de coulée (9) étant détectées, et au moins un observateur (25) étant prévu, lequel détermine sur cette base une valeur de compensation (k ') d'une valeur de consigne (SET) de l'espacement entre rouleaux (8b), la valeur réelle (ACT) de l'espacement entre rouleaux étant, en tant qu'une des grandeurs d'entrée pour cet observateur (25), utilisée pour compenser un déphasage et/ou une amplitude de la valeur réelle (ACT) de l'espacement entre rouleaux.
PCT/EP2022/073152 2021-08-25 2022-08-19 Procédé et dispositif de régulation d'une installation de coulée continue WO2023025669A1 (fr)

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CN202280057896.XA CN117858775A (zh) 2021-08-25 2022-08-19 用于调节连铸系统的方法和设备
KR1020247008365A KR20240055000A (ko) 2021-08-25 2022-08-19 스트랜드 주조 시스템을 조절하기 위한 방법 및 디바이스

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EP21192957.5 2021-08-25
EP21192957.5A EP4140616A1 (fr) 2021-08-25 2021-08-25 Procédé et dispositif de régulation d'une installation de coulée continue

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007042170A1 (fr) 2005-10-12 2007-04-19 Siemens Vai Metals Technologies Gnbh & Co. Procede pour realiser la coulee continue d'une masse de metal en fusion
AT518461A1 (de) 2016-04-11 2017-10-15 Primetals Technologies Austria GmbH Gießspiegelregelung mit Störgrößenkompensation
WO2018108652A1 (fr) 2016-12-13 2018-06-21 Primetals Technologies Austria GmbH Procédé et dispositif de régulation d'une installation de coulée continue

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007042170A1 (fr) 2005-10-12 2007-04-19 Siemens Vai Metals Technologies Gnbh & Co. Procede pour realiser la coulee continue d'une masse de metal en fusion
AT518461A1 (de) 2016-04-11 2017-10-15 Primetals Technologies Austria GmbH Gießspiegelregelung mit Störgrößenkompensation
WO2018108652A1 (fr) 2016-12-13 2018-06-21 Primetals Technologies Austria GmbH Procédé et dispositif de régulation d'une installation de coulée continue

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KR20240055000A (ko) 2024-04-26
EP4140616A1 (fr) 2023-03-01

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