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    • 专利摘要:
    Method and apparatus for controlling a continuous casting plant, wherein the continuous casting plant has a mold (1) and a strand guide (8) arranged downstream of the mold (1), in which mold (1), in particular via a feed device (4), liquid metal ( 3) is cast, which solidifies on walls (1a) of the mold (1), so that a metal strand (7) with a solidified strand shell (5) and a still liquid core (6) is formed, wherein the metal strand (7) by means of spaced apart 15 rolls (8b) of the strand guide (8) is pulled out of the mold (1), wherein a measured variable is determined, which correlates with the fluctuation of the casting mirror forming in the mold, processes this measured variable by including at least one calculation rule and is used to reduce the variations in the casting level, the mutual distance between opposing rollers (8b) being used to reduce the variations in the casting level. the strand guide is changed before the solidification point (D) 25.
    公开号:AT519390A1
    申请号:T51133/2016
    申请日:2016-12-13
    公开日:2018-06-15
    发明作者:Ing Paul Felix Dollhäubl Dipl；Josef Watzinger Dr；Ing Philipp Wieser Dipl
    申请人:Primetals Technologies Austria GmbH；
    IPC主号:
    专利说明:

    description
    Method and device for controlling a continuous casting plant Technical field
    The present invention relates to a method for controlling a continuous casting, wherein the continuous casting has a mold and a mold downstream strand guide, wherein in the mold, in particular via an inflow device, liquid metal is poured, which solidifies on walls of the mold, so that a Formed metal strand with a solidified strand shell and a still liquid core, wherein the metal strand is pulled out by means of spaced rollers of the strand guide from the mold, wherein a measured variable is determined, which correlates with the fluctuation of forming in the mold casting mirror, this measure with involvement is processed by at least one calculation rule and used to reduce the variations in the casting level. The invention also includes a corresponding device.
    The method can be used in continuous casting. In general, the method can be used advantageously in all continuous casting processes with high casting speeds, because here a highly dynamic regulation / control of the casting level is increasingly necessary.
    State of the art
    In continuous continuous casting, from a metallurgical point of view, it is generally of great importance for the formation of a uniform crack-free strand shell and a homogeneous, defect-free slab that casting-material fluctuations are within a required narrow tolerance range.
    Due to the different phenomena that influence the casting level, a regulation is necessary to keep it constant. These phenomena include: 1. Transient flows into the mold via the inlet device: clogging of the inflow device, which can be designed as a stopper or slide, clogging of the immersion tube or the release and flushing of these clogging, changes in the amount of purging gas in the middle of the plug, argon is blown in to generate an overpressure in the dip tube (preventing the suction of air), which can cause turbulence in the steel bath in the mold), - distributor weight fluctuations caused, for example by not ideal regulation of the inflow of the pan into the distributor (distributor = intermediate vessel between pan and mold). By this pressure change, another flow is produced at the same stopper opening, which must be counteracted with regulation, - Viscosity change of the steel at e.g. Pan change. 2. Change in the volume of liquid steel in the mold: - Form change in the mold - Glow level set point change (e.g.
    3. Transient flows from the mold: - extrusion pumps - casting speed changes - bent rollers - intended changes of the casting gap (for example soft reduction)
    All of these phenomena lead to changes in the pouring level and these changes must be counteracted. Since many of the phenomena occur very suddenly and unexpectedly, the dynamics of the control play a very important role.
    Increased in special steel grades, eg. As peritectic steels or ferritic stainless steels, it comes during the continuous casting process to an irregular occurring raising and lowering of the bath level (= cyclic), which is known as "bulging" ("mold level hunting") It is a feature of this cyclical disturbance that it occurs at a certain casting speed with a period approximately equal to the average roll pitch (ie the distance between the rolls in In particular, the extrusion pumping occurs in continuous casting plants, in which the roll division in the strand guide is constant over longer sections (ie, several rollers following one another in the transport direction of the strand have the same A) have each other). In addition to the fundamental wave, harmonic harmonics also occur. It could be stated that the extrusion pumping only occurs above an empirically determined critical casting speed, which in turn depends on the equipment used and on the mode of operation. A limitation of
    Casting speed, however, is unacceptable from the standpoint of a steady trend towards capacity increases.
    A control technology for damping the Bad- or Gießspiegelschwankungen is already known for example from DE 102 14 497 Al. In this method, the power consumption is measured on one or more drive rollers and the current consumption measurements are taken into account as a correction value for the flow control in the supply of molten metal from the tundish to the continuous casting mold by the current measurement value is connected as a disturbance in a control loop. Changes in the current consumption caused, for example, by a change in the casting speed, or cyclically recurring disturbances in the current consumption values, for example caused by rolling impacts of out-of-round driver roles, are filtered out in advance from the measured current consumption signal. However, the control method described is not suitable, for example, to compensate for input dead times, so that only a portion of the attributable to the extrusion pumping mirror movements can always be eliminated.
    From the patent application A 50301/2016 a control method for the casting level of a continuous casting plant is known, where the height of the casting mirror, the target value for the height of the casting mirror and other signals and the provisional or a final nominal position are fed to a controller and the controller determines a compensation value , which is switched to the provisional target position, so that the final nominal position, on the basis of which in conjunction with the actual position of the inlet means a manipulated variable for the inflow means of the mold is determined, corresponding to the provisional nominal position corrected by the compensation value.
    A control method is known from WO 2010/149 419 A1, where the observer comprises a model of the continuous casting mold, by means of which the observer determines an expected value for the casting level. The observer has a number of vibration compensators, by means of which, based on the difference between the height of the casting mirror and the expected value, a respective interference component related to a respective interference frequency is determined. The sum of the noise components corresponds to the compensation value.
    In the cited publications, the regulation of the casting level is realized by the adjustment of the inflow device of the mold, which has only a low dynamics. Thus it is not possible, for example, to compensate for the frequencies of greater than or equal to 0.6 Hz occurring in continuous casting from a speed of greater than or equal to 2 m / min, which cause irregularities in the steel product and thus reduce the quality of the product. So far, the problem of "high frequency bulging", ie the buckling compensation of extrusion pumping with frequencies greater than or equal to 0.6 Hz, has not yet been solved in the documents of the prior art.
    Object of the invention
    It is therefore an object of the present invention to overcome the disadvantages of the prior art and to propose a method for controlling a continuous casting plant, by means of which a higher dynamics and a better quality of the casting mirror can be achieved. In particular, should be able to be compensated with the process oscillations of the extrusion pumping in a frequency range greater than or equal to 0.6 Hz.
    Presentation of the invention
    This object is achieved by a method for controlling a continuous casting, wherein the continuous casting a mold and a mold downstream strand guide, wherein in the mold, in particular via an inflow device, liquid metal is poured, which solidifies on walls of the mold, so that forming a metal strand with a solidified strand shell and a still liquid core, wherein the metal strand is pulled out by means of spaced rollers of the strand guide from the mold, wherein a measured variable is determined, which correlates with the fluctuation of forming in the mold casting mirror, this measure processed with the involvement of at least one calculation rule and used to reduce the variations in the pouring mirror. It is provided that to reduce the fluctuations of the casting mirror, the mutual distance of opposing roles of the strand guide is changed before the Durcherstarrungspunkt.
    It is thus caused by the calculation rule by means of salaried roles of the strand guide a fluctuation-regulating movement. The mutual distance of opposing rollers, between which the strand is guided, has a direct effect on the liquid core of the strand and directly changes the casting mirror, the fluctuations of the casting mirror are corrected immediately. This allows a more accurate and dynamic control of the casting level. Lower variations in the casting level again bring about a quality improvement of the strand or of the slab end product, such as, for example, a reduction of inclusions or a crack prevention. Thus, in-phase vibrations with higher frequencies can be generated by changes in the roll spacing. On the other hand, the movement of the inflow device, which determines the amount of liquid metal that enters the mold, transfers more slowly to the mold level, because liquid metal still below the feed device flows into the mold when the position of the inlet device is changed. In this respect, the inflow device can be used to achieve an in-phase change in the position of the inflow device only at lower frequencies or, owing to this additional, non-compensatable dynamics, only a lower level of control can be achieved.
    According to the invention can be achieved by changing the mutual distance of opposing roles control or regulation of the casting mirror. The method requires only adjustable rollers, which are arranged in front of the Durcherstarrungspunkt. The Durcherstarrungspunkt is, seen along the strand guide, the place where the core of the strand or the slab is already fixed. However, a regulation or control of the casting level is only possible before the solidification, ie where the strand or the slab in the core is still liquid. The rollers, whose mutual distance is changed to reduce variations in the level of the casting, may or may not be those rollers that are driven to pull the metal strand out of the mold.
    Advantageously, the mutual distance of opposite rollers of the strand guide is changed cyclically. In this case, the method according to the invention can be used as the only control or control method for the casting level (in combination with the flow control of the inflow device), or in combination with other control or control method for the casting level by the inflow device. In a combination of control or control method, the individual control or control methods can be operated independently.
    In particular, if (also) the "bulging" is to be compensated, the cyclical changes in a frequency range up to greater than or equal to 0.6 Hz, preferably up to 5 Hz, can be the change of the roll spacing can be done with frequencies that are greater than or equal to 0.6 Hz, which are in particular up to 5 Hz.
    For example, if only the rule or rule acting on the rollers can be used. Control method is applied, the cyclic changes of the roll spacing in the frequency range of 0 to 0.6 Hz, 0 to 1 Hz, 0 to 2 Hz, 0 to 3 Hz, 0 to 4 Hz or from 0 to 5 Hz. If the control method according to the invention for reducing the variations in the casting level with other control or control method for reducing the fluctuations of
    Gießspiegels is combined, such as with the aforementioned control method using the inflow device of the mold, that could or the other methods cover a lower frequency range (eg from 0 to 0.6 Hz), while the inventive method covers only the higher frequency range (eg 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).
    In a further preferred embodiment variant of the method according to the invention, it is provided that a plurality of roller segments with one or more rollers are arranged along the strand guide on both sides, wherein at least one roller segment is adjusted normal to the strand guiding direction. The term roller segment also includes so-called grids (= "grids") which are typically arranged directly below the mold. By "normal to the strand guide direction" is meant any adjustment that is substantially normal to the strand guiding direction, which includes both pivoting and parallel shifting of a roller segment
    Strand guide direction divided into several segments, each segment includes two opposing roller segments.
    Advantageously, a roll segment arranged close to the mold is adjusted. Insofar it can be provided that at least one roller segment of the first segment is adjusted. It can therefore be provided that the uppermost, ie the mold closest to, roller segment is adjusted. The large amplification of the actuator, which engages directly, enables maximum dynamics. The factor relating to the change of the roll spacing in the uppermost segment and its influence on the pouring mirror is typically about 1:10 (pivotable segments) or 1:20 (parallel segments). This means that by increasing the roller spacing of 0.1 mm, a drop of the casting mirror in the
    Mold is effected by 1mm or 2mm. As a result, only small changes in the roll distance are needed, which can be accomplished in a very short time to compensate for high frequencies of extrusion pumping up to 5 Hz can.
    Due to the selective adjustment of individual roller segments, each with a plurality of rollers normal to the strand guiding direction, the distance between oppositely arranged rollers is reduced in opposite directions to the fluctuations of the casting mirror in order to compensate for variations in the variations in the casting level. By this compensation, the stability of the continuous casting is significantly increased and with constant quality of the steel product high casting speeds are possible.
    According to a preferred embodiment of the method according to the invention, it is provided that at least one roller segment is pivoted. The pivot axis is preferably closer to the mold, so that the more distant from the mold part of the roller segment is deflected more. The outer roller segment, so that on the outwardly curved side of the strand guide, could be fixed, be realized by a fixed outer frame. The opposite roller segment, that is the one on the inwardly curved side of the strand guide, is pivoted. It has e.g. an inner frame which carries the rollers and which is pivotally mounted. It would also be conceivable that the inner roller segment is fixedly mounted and the outer roller segment is pivoted relative to the inner roller segment.
    As an alternative to pivoting of roller segments, provision can be made for at least one roller segment to be adjusted in parallel alignment with an opposite roller segment arranged along the strand guide, which in turn allows selective adjustment of the roller spacing between individual roller segments and rollers. The outer roller segment, so that on the outwardly curved side of the strand guide, could be fixed, be realized by a fixed outer frame. The opposite roller segment, ie the one on the inwardly curved side of the strand guide, is then translationally displaced in the direction of the outer roller segment. It would also be conceivable here that, conversely, the inner roller segment is fixed, while the opposite outer roller segment is displaced translationally.
    By the distance of the rollers of two opposite roller segments, the volume of liquid metal in the core of the strand can be determined and thus draw a conclusion on a relative casting mirror change.
    According to a particularly preferred embodiment variant of the method according to the invention, at least one roller segment is adjusted by an adjusting device which comprises at least one hydraulic or electromechanical actuator (for example hydraulic cylinder or electric spindle drive). In order to allow optimum reaction time with respect to the setting of the roller spacing with regard to casting mirror fluctuations, a proportional valve is preferably used for at least one hydraulic cylinder.
    An embodiment of the invention provides that frequencies of the variations of the casting mirror are detected in a frequency range of 0 to 5 Hz and the fluctuations are compensated for by means of cyclically opposing change of the roll spacing of rolls of the strand guide.
    An alternative embodiment of the invention provides that frequencies of the variations of the casting mirror are detected in a first frequency range and the fluctuations are compensated for by means of cyclically opposing movements of the feed device (the mold), detects further frequencies of the variations of the pouring mirror in a second frequency range and the Variations are compensated by means of cyclically opposite change in the roll spacing of rollers of the strand guide, wherein the second frequency range is above the first frequency range.
    This embodiment variant has the advantage that low-frequency fluctuations of the casting mirror, as hitherto, can be compensated for by regulation of the inflow device of the mold, while only the higher-frequency fluctuations of the casting mirror are compensated by regulating the spacing of the rollers. It is therefore possible to retrofit existing regulations for the low-frequency fluctuations with an additional control of the distance between the rollers.
    In this case, either the regulation for the inflow device and / or the control for the roll spacing could be realized with the aid of a so-called observer, as shown in A 50301/2016. According to the control technology, an observer is a system that reconstructs non-measurable quantities (states) from known input variables (eg manipulated variables or measurable disturbance variables) and output variables (measured variables) of an observed reference system. For this purpose, it simulates the observed reference system as a model and uses a controller to trace the measurable state variables, which are therefore comparable with the reference system. This avoids a model generating an error that grows over time.
    Preferably, the method variant with two frequency ranges has a first observer, which determines a first compensation value for a desired position of the supply device on the basis of frequencies of the first frequency range, and a second observer, who has a second compensation value for the roller distance of the rollers of the strand guide on the basis of frequencies of the second frequency range determined.
    As a result, the casting mirror in the mold is regulated both by the inflow into the mold and by the leadership of the metal strand, preferably in the uppermost segment, after the mold. In addition, it is advantageous that the separation of the observers on different actuators (on the one hand, the first compensation value for the desired position of the inlet device in the case of the first observer and the second compensation value for the roller spacing of the rollers of the strand guide), no interference between the observers or no negative Influencing the observers can arise with each other.
    In a particularly preferred embodiment of the method with two frequency ranges, the first observer operates 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. Due to the separate frequency ranges of the two observers has the advantage that it can not lead to interference between the observers by overlapping the frequency window, whereby, for example, the target value for the actuator of the mold level control remains the same (in the case of no bulges) or smaller than in the case without secondary compensation. As a result, Gießspiegelschwankungen be further reduced and quality losses of the steel product is greatly reduced. For this purpose, it should be mentioned that in the prior art no method is known which can compensate frequencies of the variations of the casting mirror of greater than or equal to 0.6 Hz, which is why high casting speeds with high quality of the steel product can be used by using the method according to the invention , which significantly increases the productivity of continuous continuous casting or continuous strip production plants.
    A possible device for carrying out the method according to the invention comprises means for introducing a molten metal into a mold, a strand guide comprising rollers and a measuring device for measuring variations in the casting level, which is connected to a control device. In this case, an adjusting device connected to the control device is provided, by means of which fluctuations of the casting mirror can be compensated by cyclic, the fluctuations of the casting mirror opposite change in the roll spacing of rollers of the strand guide.
    As already discussed in connection with the method, it can be provided that the adjusting device is designed for cyclical changes of the roller spacing in a frequency range up to greater than or equal to 0.6 Hz, preferably up to 5 Hz. The adjusting device may comprise at least one hydraulic or electromechanical actuator, such as a hydraulic cylinder or an electric spindle drive. Of course, the adjustment for cyclic changes of the roll spacing in a frequency range from 0 Hz, preferably to 5 Hz, be designed, as well as with hydraulic or electromechanical actuators, such as a hydraulic cylinder or an electric spindle drive.
    As also already discussed in connection with the method, it can be provided that along both sides of the strand guide several roller segments are each arranged with one or more rollers, wherein at least one roller segment is adjustable by means of the adjustment normal to the strand guide direction.
    For example, at least one roller segment can be adjustable in the uppermost, that is to say first, segment. In this case, at least one roller segment can be pivoted. Or at least one roller segment is adjustable in parallel alignment with an opposite, arranged along the strand guide roller segment. Preferably, the roller segments are adjusted so that no jumpy
    Segment transitions (= thickness changes) arise, this is called "linked procedure".
    According to the process variant with two
    Frequency ranges provides a variant of the device according to the invention that frequencies of the variations of the casting mirror in a first frequency range can be detected by means of the measuring device and these fluctuations by means of cyclically opposite movements of a feed device of the mold are compensated, and that by means of the measuring device further frequencies of the variations of the casting mirror in A second frequency range can be detected and these fluctuations can be compensated for by means of the adjusting device by means of cyclically oppositely changing the roller spacing of rollers of the strand guide, the second frequency range being above the first frequency range.
    This can for example be carried out again by means of a first and / or a second observer. The second observer comprises the same components as the first observer and works analogously, with the difference that he sets a second compensation value, not the inflow device for the mold, but the adjusting device, which is in - preferably the uppermost segment - of the strand guide located.
    The inventive method and the device according to the invention is applicable to existing continuous casting with the above 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 Gießspiegelregelung it allows highly dynamic effects that were not yet ausregelbar to suppress, for example Highly dynamic strand pumping with frequencies above 0.6 Hz.
    Brief description of the figures
    The invention will now be explained in more detail with reference to an embodiment. The drawings are exemplary and are intended to illustrate the inventive idea, but in no way restrict it or even reproduce it.
    1 shows a schematic view of a section of a continuous casting plant according to the invention,
    2 shows a schematic view of a strand guide according to the invention,
    Fig. 3 shows the schematic structure of a
    Control device of the prior art,
    FIG. 4 shows details of the first observer from FIG. 3, FIG.
    Fig. 5 shows schematically an inventive
    Control circuit comprising a first and a second observer,
    Fig. 6 shows the time course of different sizes in the control of a continuous casting.
    Embodiment of the invention
    According to FIG. 1, a continuous casting plant has a mold 1. In the mold 1 2 liquid metal 3 is poured over a dip tube, for example, liquid steel or liquid aluminum. The inflow of the liquid metal 3 into the mold 1 is adjusted by means of an inlet device 4. Shown in Fig. 1 is an embodiment of the inlet device 4 as a sealing plug. In this case, a position p of the inflow device 4 corresponds to a stroke position of the sealing plug. Alternatively, the
    Inflow device 4 may be designed as a slide. In this case, the closed position p corresponds to the slider position.
    The liquid metal 3 in the mold is cooled by means of cooling devices (not shown), so that it solidifies on walls la of the mold 1 and thus forms a strand shell. However, a core 6 is still liquid. He freezes later. The strand shell 5 and the core 6 together form a metal strand 7. The metal strand 7 is supported by means of a strand guide 8 and withdrawn from the mold 9. The strand guide 8 is arranged downstream of the mold 1. It has a plurality of roller segments 8a, which in turn have rollers 8b again. Of the roller segments 8a and the rollers 8b, only a few are shown in FIG. By means of the rollers 8b, the metal strand 7 is pulled out of the mold 1 at a withdrawal speed v.
    The liquid metal 3 forms in the mold 1 a pouring mirror 9. The pouring mirror 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 feed device 4 is tracked to adjust the inflow of the liquid metal 3 into the mold 1 accordingly. By means of a (known per se) measuring device 10, a height h of the pouring mirror 9 is detected. The height h is fed to a control device 11 for the continuous casting plant. The control device 11 determines, according to a control method, which is explained in more detail below, a manipulated variable S for the inflow device 4. The inflow device 4 is then controlled accordingly by the control device 11. As a rule, the control device 11 outputs the manipulated variable S to an adjusting device 12 for the inflow device 4. The adjusting device 12 may be, for example, a hydraulic cylinder unit. Frequencies of extrusion pumping after the mold are detected metrologically and / or determined according to f = vc / pRou * n, where vc the withdrawal speed of the strand, f the buckling frequency, n the number of harmonic frequencies (1,2, etc.) and pRoii the roller distances equivalent.
    By means of pivot axis 23 and / or adjusting device 24, the roller spacings, which correspond to the marked strand thickness d, can be adjusted in a targeted manner. This can, as shown here in Fig. 1, happen by the fact that in the first segment at least one roller segment 8a has a fixed outer frame, here about the right below the mold 1 left roller segment 8a. The opposing roller segment 8a, or the inner frame carrying this, is pivotable about a pivot axis 23 which is normal to the plane of the drawing. The pivot axis 23 may 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 location. By pivoting, the roller spacing changes in the lower roller pair of the uppermost roller segment 8a in Fig. 1, while the roller spacing of the upper pair of rollers remains the same. This is not disadvantageous because the change in the roller spacing by the method according to the invention is generally only in the range of a few tenths of a millimeter up to 2 mm.
    Not shown in FIG. 1 are any guide rollers which are connected directly to the mold and would be arranged above the uppermost roller segment 8a shown here. However, these guide rollers are usually not mutually and normal to the strand guide direction adjustable
    As an alternative to pivoting, the left uppermost roller segment 8a, ie its outer frame, could be fixed and the right upper roller segment 8a, ie its inner frame, could be displaced parallel to the strand guide direction towards the left roller segment 8a and away from it. This will change the roll spacing of all
    Pairs of roles each by the same amount. This could also be done with one or more (distributed along the strand width and / or along the strand guide direction) hydraulic cylinders.
    In Fig. 2, only one strand guide 8 is shown, which replace the strand guide 8 in Fig. 1 or - after the top segment - can complete. In Fig. 2, in each of the three illustrated segments, each roller segment 8a has three rollers 8b on each side. However, it could also be only two or more than three rollers 8b per roller segment 8a. Continuing to FIG. 1, the solid strand shell 5 and the liquid core 6 of the strand are shown up to the solidification point D. Correspondingly, adjustment devices 24 are also provided in all segments 8a through to solidification point D. The adjusting devices 24 can adjust the roller segments 8a by pivoting or by parallel displacement, as already explained in FIG. In this example, the inner roller segment 8a of the first (uppermost) segment is adjusted by pivoting about the pivot axis 23, the inner roller segment 8a of the second segment by parallel displacement by means of two adjusting devices 24. The connection of the adjusting devices 24 to the control device 11 is not shown here.
    The control device 11 implements - see Fig. 3 - inter alia, a Gießspiegelregler 13. The Gießspiegelregler 13, the height h of the casting mirror 9 is supplied. The pouring mirror controller 13 is further supplied with a desired value h * for the height h of the pouring mirror 9. The Gießspiegelregler 13 further signals are further supplied. The further signals may 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 their nominal value), 1 and others. Of the
    Gießspiegelregler 13 then determined on the basis of the deviation of the height h of the casting mirror 9 of the target value h * in particular a provisional target position p '* for the inflow device 4. The further signals can use the Gießspiegelregler 13 for its parameterization and / or for determining a pilot signal pV.
    The control device 11 also implements a first observer 14. The height h of the pouring mirror 9 and its desired value h *, the further signals and a final setpoint position p * for the feed device 4 are fed to the first observer 14. The first observer 14 determines a first compensation value k. The first compensation value k is applied to the provisional setpoint position p '*, thus determining the final setpoint position p *. On the basis of the deviation of the actual position p from the final nominal position p * then the manipulated variable S is determined, with which the inflow device 4 is driven. In general, the control device 11 implements a subordinate position controller (not shown) for this purpose.
    For the sake of good order, it should be emphasized once again that the first and second observers 14, 25 are not persons, but functional blocks implemented in the control device 11.
    The difference between the provisional nominal position p '* and the final nominal position p * corresponds to the first compensation value k determined 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 provisional desired position p '* can also be supplied to the first observer 14 as an alternative to the final desired position p *. Because due to 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) desired position p '*, p * is tapped, can thus be before or after a node 16 as needed, at which the first compensation value k is switched to the provisional target position p' *. However, the tapping point 15 should lie in front of a node 16 'at which the precontrol signal pV is applied.
    The first observer 14 has a determination block 17. The determination block 17, the height h of the casting mirror 9, the other signals and the final desired position p * are supplied. The determination block 17 has a model of the continuous casting plant. Using the model, the determination block 17 determines an expected (ie model-calculated) height for the pouring mirror 9 on the basis of the further signals and the final nominal position p *. Based on the expected height, the determination block 17 then determines an expected (ie model-based calculated) fluctuation value 5h for the Height h of the pouring mirror 9, that is, the short-term fluctuation. For example, the determination block 17 can average the height h of the pouring mirror 9 and subtract the resulting average from the expected height. The determined fluctuation value 5h thus reflects the expected fluctuation of the height h of the pouring mirror 9. Based on the fluctuation value 5h, the determination block 17 then determines 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 taken in this embodiment of the present invention. FIG. 4 again shows the first observer 14 with the determination block 17. In the context of the present invention, however, the determination block 17 as shown in FIG. 4 is only one of several components of the first observer 14. Thus, for example, the first observer 14 also has a first analysis element 18. The first analysis element 18 is supplied with the fluctuation value 5h. The first analysis element 18 determines therefrom the frequency components of the fluctuation value 5h. Preferably, a second analysis element 19 is additionally present. The second analysis element 19 is supplied with an additional signal Z. The second analysis element 19 determines therefrom the frequency components of the additional signal Z.
    The additional signal Z may be an extraction 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 pull-out force F is directed parallel to the withdrawal speed v. Alternatively, it may be the withdrawal speed v itself. These two alternatives are preferred. However, it is also possible to use as additional signal Z, for example, a force signal F ', 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 withdrawal speed v. Again alternatively, the additional signal Z may be a local strand thickness d, which is measured by a measuring device 21 in the strand guide 8. The first analysis element 18 supplies 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, in conjunction with the withdrawal speed v, determines the associated wavelengths which correspond to the frequency components of the fluctuation value 5h and optionally also of the additional signal Z. The withdrawal speed v is supplied to the first observer 14 for this purpose and to the selection member 22 within the first observer 14. The selection element 22 determines the wavelengths at which the associated frequency component of the fluctuation value 5h possibly also the associated frequency component of the additional signal Z is above a threshold value S1, S2. The respective threshold value Sl, S2 can be determined individually for the frequency components of the fluctuation value 5h on the one hand and the frequency components of the additional signal Z on the other hand. These wavelengths are preselected by the selector 22. Within each in itself more coherent
    Areas of preselected wavelengths of the fluctuation value 5h, the selection member 22 then determines those wavelengths Ai (i = 1, 2, 3, ...), in which the respective frequency component of the fluctuation value 5h assumes a maximum. The number of wavelengths ai is not limited. These wavelengths λi selects the selector 22 (finally). The selected wavelengths λi supplies the selection element 22 to the determination block 17. The determination block 17 carries out a filtering of the height h of the pouring mirror 9 and the final setpoint position p * for the wavelengths λi selected by the selection element 22. The first compensation value k is determined by the determination block 17 only on the basis of the filtered height h of the pouring mirror 9 and the filtered final desired position p *. The other frequency components of the height h of the pouring mirror 9 and the final setpoint position p * are disregarded by the determination block 17 as part of the determination of the first compensation value k. The selection element 22 can also be predetermined predetermined wave ranges. In this case, the predetermined wave ranges represent an additional selection criterion. In particular, wavelengths at which the associated frequency component of the fluctuation value 5h, if appropriate, also the associated frequency component of the additional signal Z is above the respective threshold value S1, S2, are selected only if they additionally within a the predetermined wavelength ranges are. Otherwise, they are not selected even if the associated frequency component of the fluctuation value 5h possibly also the associated frequency component of the additional signal Z is above the respective threshold value S1, S2.
    As previously mentioned, the second observer 25 has identical constituents as the first observer 14, analyzes frequencies of the strand pumping after the mold 1 and provides a second compensation value k 'for the adjustment device 24. FIG. 5 shows a control circuit comprising a first and a second observer 14, 25. The first observer 14 provides a first compensation value k for the inflow device 4 of the mold 1, whereby the pouring level 9 in the mold 1 is regulated. Simplified said, the first observer 14 and the inflow means 4 of the mold 1 together constitute a standard system for controlling the pouring mirror 9 of the mold 1, which is used for the compensation of frequencies in the first frequency range and thus provides a controller 27 for frequencies of the The second observer 25, which is connected to the adjusting device 24, represents a controller for frequencies of the second frequency range 26 and provides a second compensation value k 'before.
    Instead of the first observer 14, which controls the inflow means 4 of the mold 1, another control method could be provided, and / or instead of the second observer 25, which controls the adjusting means 24 of the rollers 8b, could use a different control method be provided.
    It could also be provided only a single control method that controls only the adjusting device 24 of the rollers 8b, while the inflow device 4 of the mold 1 is not used to compensate for the fluctuations of the casting mirror. This single control method could be the second observer 25, but also another control method. In this case, the second observer or another sole control or regulation method would usually cover a larger frequency range than two control methods. This frequency range could then be e.g. cover 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. Along the vertical axis, the position of the inlet device 4 labeled "Pos (4)" is shown in the first (uppermost) illustration, in the second figure the height of the casting mirror in the mold 1, labeled "M_L", and in FIG third figure shows the flow of steel from the mold 1, labeled "St_Fl." For better understanding, the control "Comp" is still disabled at time t = 0 and then turns on, which in the last figure shows the states "0" for the deactivated control and "1" for the activated control is shown. In the first three representations, it can be clearly seen that both the position of the feed device 4 changes cyclically, as well as the height of the casting mirror and, consequently, the steel flow from the mold. By activating the control, here by changing the position "Pos (4)" of the inlet device 4, the cyclic fluctuations of the pouring mirror "M_L" are reduced. In the method according to the invention, in order to reduce the variations in the casting level, in addition to or alternatively to changing the position "Pos (4)", the feed device 4 would be cyclically changed according to the mutual spacing of the rolls 8b in the uppermost segment.
    LIST OF REFERENCES: 1 mold la walls of the mold 2 dip tube 3 liquid metal 4 inlet device 5 strand shell 6 core 7 metal strand 8 strand guide 8a roller segments 8b rollers 9 casting mirror 10 measuring device 11 control device 12 adjusting 13 Gießspiegelregler 14 first observer 15 tapping point 16, 16 'nodes 17 determination block 18 , 19 Analysis elements 20 Temperature sensor 2 1 Measuring setup 2 2 Selection 2 3 S witching axis 2 Sending device 2 5 two-way monitoring 26 Controllers for frequencies of the 2nd.
    Frequency range 27 controllers for frequencies of the 1.
    Frequency range D solidification point d strand thickness F pull-out force F 'force signal h height of the pouring level h * target value for the height of the pouring level k first compensation value k' second compensation value p position of the feed device p *, p '* setpoint positions pV pilot signal SS size ll S1 , S2 threshold values T temperature v take-off speed Z additional signal δh fluctuation value
    权利要求:
    Claims (18)
    [1]
    claims
    1. A method for controlling a continuous casting, wherein the continuous casting a Kokille (1) and one of the mold (1) downstream strand guide (8), wherein in the mold (1), in particular via an inlet device (4), liquid metal (3 ), which solidifies on walls (1a) of the mold (1), so that a metal strand (7) with a solidified strand shell (5) and a still liquid core (6) is formed, wherein the metal strand (7) by means of spaced arranged rolls (8b) of the strand guide (8) is pulled out of the mold (1), wherein a measured variable is determined, which correlates with the fluctuation of the casting mold forming in the mold, processes this measure with the inclusion of at least one calculation rule and to reduce the fluctuations of the casting mirror is used, characterized in that to reduce the fluctuations of the casting mirror of the mutual distance of opposing rollers (8b) the strand guide is changed before the solidification point (D).
    [2]
    2. The method according to claim 1, characterized in that the mutual distance of opposing rollers (8b) of the strand guide is cyclically changed.
    [3]
    3. The method according to claim 2, characterized in that the cyclic changes in a frequency range up to greater than or equal to 0.6 Hz, preferably to 5 Hz, are.
    [4]
    4. The method according to any one of claims 1 to 3, characterized in that along the strand guide (8) on both sides a plurality of roller segments (8a) each having one or more rollers (8b) are arranged, wherein at least one roller segment (8a) adjusted normal to the strand guiding direction becomes.
    [5]
    5. The method according to claim 4, characterized in that at least one roller segment (8a) of the first segment is adjusted.
    [6]
    6. The method according to claim 4 or 5, characterized in that at least one roller segment (8a) is pivoted.
    [7]
    7. The method according to any one of claims 4 to 6, characterized in that at least one roller segment (8a) is adjusted in parallel alignment with an opposite roller segment (8a).
    [8]
    8. The method according to any one of claims 1 to 7, characterized in that at least one roller, in particular a roller segment (8a), by an adjusting device (24) is adjusted, which comprises at least one electromechanical or hydraulic actuator.
    [9]
    9. The method according to any one of claims 1 to 8, characterized in that frequencies of the variations of the Gießspiegels detected in a frequency range of 0 to 5Hz and the variations by means of cyclically opposite change of the roller spacing of rollers (8b) of the strand guide (8) are compensated.
    [10]
    10. The method according to any one of claims 1 to 8, characterized in that frequencies of the variations of the Gießspiegels are detected in a first frequency range and the fluctuations by means of cyclical opposite movements of the Zuflusseinrichtung (4) are compensated, further frequencies of the variations of the Gießspiegels in a second Frequency range detected and the fluctuations are compensated by means of cyclically opposite change in the roll spacing of rollers (8b) of the strand guide (8), wherein the second frequency range is above the first frequency range.
    [11]
    11. A device for carrying out a method according to any one of claims 1-10, comprising means for introducing a molten metal into a mold (1), a strand guide (8) comprising rollers (8b), a measuring device (10) for measuring variations of the casting mirror , which is connected to a control device (11), characterized in that with the control device (11) connected adjusting device (24) is provided, by means of which fluctuations of the casting mirror by cyclic, the variations of the casting mirror opposite change in the roll spacing of rollers (8b ) of the strand guide (8) are compensated.
    [12]
    12. The device according to claim 11, characterized in that the adjusting device (24) is designed for cyclic changes of the roller spacing in a frequency range up to greater than or equal to 0.6 Hz, preferably to 5 Hz.
    [13]
    13. The apparatus of claim 11 or 12, characterized in that the adjusting device (24) comprises at least one hydraulic or electromechanical actuator.
    [14]
    14. Device according to one of claims 11 to 13, characterized in that along the strand guide (8) on both sides a plurality of roller segments (8a) each having one or more rollers (8b) are arranged, wherein at least one roller segment (8a) by means of the adjusting device ( 24) is normal to the strand guide direction adjustable.
    [15]
    15. The apparatus according to claim 14, characterized in that at least one roller segment (8a) of the first segment is adjustable.
    [16]
    16. The apparatus of claim 14 or 15, characterized in that at least one roller segment (8a) is pivotable.
    [17]
    17. Device according to one of claims 14 to 16, characterized in that at least one roller segment (8a) in parallel alignment with an opposite, along the strand guide (8) arranged roller segment (8a) is adjustable.
    [18]
    18. Device according to one of claims 11 to 17, characterized in that by means of the measuring device (10) frequencies of the variations of the casting mirror in a first frequency range are detectable and these fluctuations by means of cyclically opposite movements of an inlet device (4) of the mold (1) compensated are, and that by means of the measuring device (10) further frequencies of the variations of the casting mirror in a second frequency range are detectable and these fluctuations by means of cyclically opposing change of the roller spacing of rollers (8b) of the strand guide (8) are compensated by the adjusting device (24), wherein the second frequency range is above the first frequency range.
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    同族专利:
    公开号 | 公开日
    US20190308238A1|2019-10-10|
    AT519390B1|2020-09-15|
    EP3554744B1|2020-08-26|
    CN110062672A|2019-07-26|
    US11110512B2|2021-09-07|
    WO2018108652A1|2018-06-21|
    EP3554744A1|2019-10-23|
    KR20190094368A|2019-08-13|
    引用文献:
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    AT413023B|1999-01-14|2005-10-15|Sumitomo Heavy Industries|DEVICE FOR REGULATING THE METAL MIRROR IN A CONTINUOUS COIL|
    EP1095720A1|1999-10-25|2001-05-02|SMS Demag AG|Frame for strand guiding in a continuous casting machine, particularly for thin steel slabs|
    DE102004002783A1|2004-01-20|2005-08-04|Sms Demag Ag|Method and device for determining the position of the sump tip in the casting strand in the continuous casting of liquid metals, in particular of liquid steel materials|
    DE102006018757A1|2006-04-22|2007-10-25|Sms Demag Ag|Method for determining the roll spacings of support rollers and strand guide framework of a continuous casting plant for casting liquid metals, in particular liquid steel materials|
    WO2014177605A1|2013-05-03|2014-11-06|Tbr Casting Technologies Gmbh|Method and device for controlling the molten metal level in an ingot mold|CN112808959A|2019-11-16|2021-05-18|上海梅山钢铁股份有限公司|Method for replacing tundish at high liquid level of crystallizer and capable of remarkably improving success rate|US4597048A|1983-09-07|1986-06-24|United States Steel Corporation|Digital flow regulation of liquid-level control for a continuous casting mold|
    DE19745547A1|1996-11-08|1999-06-02|Mannesmann Ag|Process and plant for the continuous casting of thin slabs|
    AT410409B|2001-04-03|2003-04-25|Voest Alpine Ind Anlagen|METHOD FOR CONTINUOUSLY casting metal melts, AND CONTINUOUS CASTING SYSTEM FOR IMPLEMENTING THE METHOD|
    AT502525B1|2005-10-12|2008-05-15|Voest Alpine Ind Anlagen|METHOD FOR CONTINUOUSLY GRAZING A METAL MELT|
    DE102008025548A1|2008-05-28|2009-12-03|Sms Siemag Aktiengesellschaft|Strand guide, in particular for a continuous steel slab caster|
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    CN101920316B|2010-08-03|2015-08-19|中国重型机械研究院有限公司|A kind of method for reforming continuous casting machine solving liquid level fluctuation of crystallizer|
    KR101360552B1|2011-12-19|2014-02-11|주식회사 포스코|Continuous Casting Device|
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    AT518461B1|2016-04-11|2019-12-15|Primetals Technologies Austria GmbH|Mold level control with disturbance variable compensation|CN113102707A|2021-03-29|2021-07-13|中国重型机械研究院股份公司|Billet discharging system and method of billet continuous casting machine|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    ATA51133/2016A|AT519390B1|2016-12-13|2016-12-13|Method and device for controlling a continuous caster|ATA51133/2016A| AT519390B1|2016-12-13|2016-12-13|Method and device for controlling a continuous caster|
    CN201780077251.1A| CN110062672A|2016-12-13|2017-12-06|Method and apparatus for adjusting continuous casting facility|
    EP17808939.7A| EP3554744B1|2016-12-13|2017-12-06|Method and device for regulating a strand casting system|
    PCT/EP2017/081615| WO2018108652A1|2016-12-13|2017-12-06|Method and device for regulating a strand casting system|
    KR1020197016831A| KR20190094368A|2016-12-13|2017-12-06|Method and apparatus for adjusting strand casting system|
    US16/466,313| US11110512B2|2016-12-13|2017-12-06|Method and device for regulating a continuous casting machine|
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