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
  • B22D11/12—Accessories for subsequent treating or working cast stock in situ
  • B22D11/1206—Accessories for subsequent treating or working cast stock in situ for plastic shaping of strands
• • 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
• • 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 invention relates to a method for controlling and / or controlling a Anstellsegmentes in a continuous casting, wherein the Anstellsegment has a subframe and an upper frame, which are adjustable by adjusting in ih ⁇ rer position and / or tilt relative to each other, wherein a strand between an input and an output is guided in a casting direction of the subframe and the O- superframe, wherein each adjusting element is assigned a respective position controller.
• the invention relates to a device for controlling and / or controlling a Anstellsegmentes in a continuous casting, wherein the Anstellsegment has a subframe and a top frame, which are adjustable by four adjusting elements in position and / or tilt relative to each other, wherein a strand between a Entrance and an exit in a casting direction of the sub-frame and the upper frame is performed.
• Continuous casting plants are used for continuous casting of square (billets) or rectangular (slabs) cross sections in molds.
• the strand is performed in slab after leaving a cooled mold preferably for supporting a strand shell and to achieve a reduction in thickness in Anstellsegmenten.
• a Anstellsegment preferably consists of a movable upper and a fixed subframe, both of which are provided with a plurality of rollers.
• the upper frame of a Anstellsegmentes can ⁇ example as compared to the subframe via two hydraulically operable adjusting elements in the vicinity of the input and the output are positioned vertically within certain limits.
• the aim of a preferably automated adjustment or adjustment of Anstellsegmentes is to set an input jaw width between the first upper and lower rollers at the entrance and the last upper and lower rollers at the output to predetermined values. Because of, for example, a thermal shrinkage of the strand, the input mouth width at Ein ⁇ transition of Anstellsegmentes must be greater than an output mouth width at the output of Anstellsegmentes.
• the Anstellsegment here comes the task to give a strand or generally a conveyed a certain shape or to provide a certain thickness of a strand at the output of Anstellsegmentes. An error of the thickness of the strand must preferably ⁇ be less than 0.1 mm. Furthermore, the Anstellseg ⁇ ment the task, for example, to support a partially solidified strand shell of a liquid metal.
• the invention has for its object to provide a method and apparatus for increasing the accuracy in the control available.
• a position correction value ermit ⁇ telt is.
• the longitudinal controller permanently the position and / or angle of the upper frame with respect to the input jaw width and the output jaw width corrected when a maximum allowable value is exceeded. The correction is carried out by means of position correction values.
• At least on the input side two position controller with egg ⁇ nem cross-controller for controlling and / or controlling a tilt transversely to the casting direction and / or for controlling and / or controlling a position difference between a first of the adjusting elements and a prepared second of the adjusting elements.
• a skew, in ⁇ play of the upper frame, transversely to the casting direction CONTROL lines ⁇ and be limited.
• each position controller is assigned a force limiting controller.
• Force limiters are used to avoid damage or malfunction in plant operation.
• the skew between the input and the output can not be eliminated by the cross regulators alone.
• forwarding of position correction values for the position regulator to the input side and for the position controller on the output side an inclined position can be continuously maintained sition by the position correction values in the required Po ⁇ in the longitudinal direction, ie in the casting direction.
• a skew actual value is determined by a difference of Positi ⁇ ons staple of adjusting elements at the input and / or output. Since the individual position controller preferably already have individual position transducer which ⁇ se procedure is advantageous. Expediently, a mean value of the position values at the input and / or output is provided for the subtraction . Since the input and the output of a respective Schrägla ⁇ ge may have in the transverse direction, is advantageous at the output for the determination of the actual value of skew, an averaging of the individual ⁇ NEN position values of the adjusting elements at the input and / or adjusting elements.
• a further increase the control accuracy is thereby he ⁇ sufficient that the cross-regulator and / or the longitudinal control having a nonlinear characteristic.
• unwanted actual values can thus be ignored for the transverse controller and / or the longitudinal controller.
• the transverse regulator and / or the longitudinal regulator is so non-linear that an oblique position is reduced by increasing the respective lower side.
• the cross-controller and / or the longitudinal controller does not respond to negative deviations.
• a particular embodiment of the invention is that in case of failure of a position sensor of the associated position controller by a fault controller, which receives a nominal value of a force feedback of the nearest adjustment, till ⁇ triggers.
• the position controller is replaced, for example, by a pro ⁇ proportional error controller for the force in case of failure of a posi ⁇ onsgebers.
• the position correction value of the cross-controller and / or the longitudinal controller for the duration of the failure is maintained at its last value in case of failure of a position sensor.
• the removal of the donor disorder can therefore be placed directly on the old correction state ⁇ with advantage again.
• a position correction value for the positioning of the respective adjustment element is determined in case of failure or failure to achieve a position setpoint of a Positionsreg ⁇ lers on the respective force limiting controller.
• the force limiting controller generates a position correction value when a force limit is exceeded. Is reached a force limit or already exceeded, the position correction value to the current position value can be added advantageously ⁇ are added, which results in an immediate decrease in the achieved force.
• a force limiting regulator preferably comprises at least three partial force controllers.
• At least one of the following predetermined force limits and / or force values is used for each adjustment: A maximum force in the opening direction, the direction of a maximum force in the closing ⁇ , a minimal force in the closing direction.
• the position correction value for Po ⁇ sitionsregelung is determined via a cascade control, wherein an error control loop comprises a power limit control circuit includes and the force limiting regulation circuit includes a forward ⁇ lay-locked loop and the skew control circuit includes a position control loop.
• Parameterisation of the control loops can thus systematically from the inside to the outside, starting with the position controls on the Schräglagenbe ⁇ grenzungsregler, the force limiting controller be made to the error regulators.
• the device-related problem is based on the solved a ⁇ gangs said apparatus characterized in that for regulation and / or control of the position and / or tilt in a direction of casting a longitudinal controller is provided.
• the longitudinal regulator is prepared for generating two position correction values, namely a first position correction value for at least one position controller at the input and a second position correction value for at least one position controller at the output.
• each adjusting element has a position transmitter.
• the inclined position of the Anstellsegmentes can be quickly and accurately compensated.
• a cross-controller for the regulation and / or control of the position and / or tilt transversely to the casting direction, a cross-controller for the input and a further cross-controller for the output available.
• a tilting position can be limited to advantageous width be ⁇ .
• Dynamic skews can also occur during a running, force-free positioning or static position differences can occur if, for example, the strand cross-section is trapezoidal, or an optionally inserted force limiting regulator only engages on one side of the control element.
• a cross-controller can successfully cross the tilt or skew position limit to the casting direction of Anstellsegmentes or the upper frame.
• the device is designed such that the formation of a skew for the actual value of longitudinal regulator means for the difference formation and / or averaging the position values of the adjusting elements at the input and at the output Ver ⁇ adjusting elements are present.
• the accuracy of Rege ⁇ increased lung is designed such that the formation of a skew for the actual value of longitudinal regulator means for the difference formation and / or averaging the position values of the adjusting elements at the input and at the output Ver ⁇ adjusting elements are present.
• the transverse regulators and / or the longitudinal regulator preferably have a non-linear control characteristic.
• a position controller has an error controller, which receives a force actual value of the nearest Verstellele ⁇ Mentes in case of failure of a position sensor as the setpoint.
• a force limiting controller is provided for each position controller.
• FIG 3 shows schematically the Anstellsegment in a plan view
• FIG 4 schematically shows the Anstellsegment in a side view with adjusting devices
• 5 shows a block diagram of a control device
• the continuous casting 2 is prepared with Anstell ⁇ segments 1 for guiding a strand 3.
• the Anstellsegmente 1 serve to guide the strand 3 from a vertical to a horizontal position.
• Liquid metal 6, wel ⁇ ches is stored in a tundish 7, flows or is poured through a dip tube into the mold 7a.
• the already partially solidified strand 3 is ge ⁇ leads by the Anstellsegmente 1.
• An alternate segment of the strand 3 is guided on a roller table 4 to a next processing step in the continuous casting plant. 2
• FIG. 2 shows a Anstellsegment 1 in a side view.
• the Anstellsegment 1 has a sub-frame 9 and a 0- superframe 10.
• the strand 3 is guided by means of rollers 8 through an output segment 1 up to an output EX.
• the Anstellsegment 1 can be adjusted for be ⁇ arbitrary thicknesses of a strand 3.
• Exempla ⁇ is shown here a so-called straight segment type 1 driven, apply analogous conditions for a uniformly curved segment-type or a non-uniform curved segment type.
• a uniformly curved segment type leads the strand 3 in a circular arc.
• a non-uniformly curved segment type which leads the strand 3 with a decreasing curvature, is referred to as a directional segment with decreasing curvature.
• Figure 3 shows the Anstellsegment 1 in a plan view.
• the positioning segment 1 has a first te adjusting device 12 and a second adjusting device 13.
• the Anstellsegment 1 In the vicinity of the output EX, the Anstellsegment 1, a third adjusting device 14 and a fourth Anstell ⁇ device 15.
• four adjusting devices 12, 13, 14, 15 of the upper frame 10 may Anstellsegmentes 1 ge ⁇ geninate the sub-frame 9 via two hydraulic adjusting devices 12 and 13 or 14 and 15 in the vicinity of the entrance EN and in the vicinity of the exit EX be positioned or adjusted within GeWiS ⁇ ser limits.
• Figure 4 shows such a positioning of the upper frame 10 to the subframe 9.
• the adjusting devices 12 and 13 are positioned relative to the adjusting devices 14 and 15 with a larger Anstellweite such that it comes to a tilt of the upper frame 10 relative to the lower frame 9.
• the upper frame 10 is guided in this case via a respective Gleitschutz 50 side.
• a reduction in thickness of the strand 3 is achieved.
• Figure 5 shows a device for controlling and / or control of Anstellsegmentes 1 fragmentary in a block ⁇ circuit diagram.
• the control device is prepared, each with a position regulator ⁇ S1, S2, S3 and S4 for the four Anstellsegmente 12,13,14, 15 °.
• the respective control value is yl to Y4, which tilstromwert as Servoven- or is output as a position value, provided ⁇ .
• Each position controller Sl to S4 are each a Kraftbe ⁇ assigned grenzungsregler Fl to F4.
• the position controllers Sl and S2 are assigned a transverse regulator Qi 2 for limiting an inclined position transversely to a transport or casting direction.
• the position controllers S3 and S4 are assigned a further transverse controller Q 34 for limiting or correcting an inclined position transversely to the casting direction at the output.
• As actual value input variables are the position controller Sl which positi on ⁇ onsgeber (not shown) to S4 with the respective Positionsist tone Xsi, xs2, XS3 and x powered S 4 of the individual Anstellvorrichtun- 12 to 15 are determined. The sign of the position x s for the opening direction is agreed to be positive.
• the position controller receive Sl to S4 respectively set position values W S i, W 32, W S 3, S 4 and W Positionskor ⁇ compensation values, the ermit by means of the superimposed part controller ⁇ be telt.
• the cross-Qi controller 2 and Q34 are to provide Posi ⁇ tion correction values W 3112 W 3212 W S W S 334 and prepared 434th
• the force limitation controllers F1 to F4 are also prepared for generating position correction values W SFI to W SF4 .
• the control device has a longitudinal regulator L.
• the longitudinal controller provides two position correction values , a position correction value W SEN for position correction at input EN and another position correction value W SEX for position correction at output EX.
• the position controller Sl to S4 have a linear proportional Charak ⁇ characteristic (make P-controller).
• the current position correction values W S n 2 , W 3212 , W 3334 , W S 434 of the cross-controller Q i2 and Q34 and the longitudinal controller L are maintained at their last valid values, so again when the encoder fault disappears the old correction state can be set up.
• Each force limit controller Fl to F4 consists of three partial force controllers 30, 31, 32 (see FIG. 7).
• a first partial force controller 30 serves to limit the force of a maximum Force in the opening direction 34
• a second partial force controller 31 serves to limit the force of a maximum force in the closing direction 35
• a third part of force controller 32 is the force limit of a minimum force in the closing direction 36.
• the third part of force controller 32 ensures a minimum pressing force 36 when the associated position setpoint at ⁇ game as Wsi, does not lead to the strand 3 to the contact.
• the sign of the force X F is agreed to be positive for the closing direction.
• All of the force limit controllers Fl to F4 generate position correction target values W S fi to W S f4, which are added to the position command values W S i to W S 4.
• the following is a description of the non-linear mode of action of the partial force controller 30,31,32 based on the case distinction opening the Anstellsegments, closing the Anstellsegments with strand 3 or spacers and closing the Anstellsegmentes with contacting the strand. 3
• the force limiting target value is the maximum force in Publ ⁇ voltage device 34 and greater than zero.
• the power value x F is less than zero but RESIZE ⁇ SSER the negative maximum force in the opening direction 34, is positive, a deviation of the maximum force in the opening direction 34 and the force feedback value x F and the output of the sub power controller 30 therefore limited to zero.
• the output of the fractional force controller 30 therefore provides a negative position correction setpoint for the position. This reduces the overall position setpoint W SF so that the upper frame 10 is stopped or even lowered again until the control deviation becomes zero. Since the partial force controller 30 has a proportional-integral characteristic (PI behavior), the controller output keeps the correction setpoint even if the control deviation disappears. Close the positioning segment:
• the force limit setpoint is the maximum force in the closing direction 35 and greater than zero.
• the maximum force in the closing direction 35 is greater than the actual force value x F and greater than zero, the Regelab ⁇ deviation is negative and the output of the second partial force controller 31 is therefore limited to zero.
• Exceeds the power value x F is the maximum force in the closing direction 35 due to a low position command value, the deviation is posi ⁇ tiv. Therefore, the output of the sub power controller 31 supplies a positive correction reference value W SF for the associated Positi ⁇ onsregler. This increases the overall position setpoint, so that the upper frame 10 is raised slightly. Due to the PI characteristic of the controller, the correction setpoint is retained even if the control deviation disappears.
• the minimum force command value is the minimum force in the closing direction ⁇ 36 and greater than zero.
• the control deviation is then positive and the output of the third partial force controller 32 is limited to zero. If the force actual value x F falls below the limit of the minimum force in the closing direction 36, a negative correction target value W 3 F results for the associated position controller. This reduces the overall position setpoint so that the upper frame 10 is lowered. Due to the PI characteristic of the controller, the correction setpoint is retained even if the control deviation disappears.
• Dynamic inclinations of the upper frame 10 may occur during ongoing, zero-force positioning when flow characteristics of proportional valves associated with the hydraulic biasing devices are unequal or the friction state in the hydraulic cylinders is very different.
• Static position differences can occur if the strand cross-section is trapezoidal, or one of the partial force ⁇ controller Fl to F4 engages on one side.
• the first case would meet best a feature that lowers the position of the higher side while raising the position of the low side or lowers only the position on the higher side or lifting only the positi ⁇ on on the low side and the also very dyna ⁇ mixed.
• the second case calls for a function that keeps the position at which the force limit controls are active constant and adjusts only the other side in height.
• a Rege ⁇ distribution function both cases covering is given to the second case. When the permissible inclined position is exceeded, therefore, always the low position of the higher position is tracked.
• the cross controller Qi 2 only becomes active if a maximum permissible position difference ASi 2 or skew is exceeded. If the two Anstell ⁇ devices 12 and 13 to move in a position in the required direction, the skew of the two Anstell ⁇ is offset 12 and 13 devices. If one of the two jobs prevents further positioning, because the maximum force in the closing direction 35 is reached, only the other adjusting device will compensate for the skew. An analogous behavior applies to the cross-controller Q 34 .
• the Qi 2 and Q 34 cross regulators must be of the proportional-integral type (PI controller) so that the controllers maintain the position correction as long as the skew at their limit is required, ie as long as the control deviation is zero. If the inclined position loosens transversely to the casting direction, eg due to changed system states from the respective limit, the correction intervention is also automatically reduced again. An inclination of the upper frame 10 between the input EN and the output EX can not be eliminated by the lateral regulators Qi 2 and Q 34 . In contrast to the oblique position transverse to the casting direction, the skew in the casting direction is desired. As a result, a shrinkage and / or a soft taper can be set.
• PI controller proportional-integral type
• the skew in the casting direction is forced by a corresponding specification of the position setpoints.
• the skew actual value ⁇ S ENEX is formed by a Differenzbil ⁇ tion of the averaged actual position values on the input side and on the output side of Anstellsegmentes 1 (see Figure 9). If the adjusting devices 12, 13 at the input EN and the adjusting devices 14, 15 at the output EX can move in the required direction, the inclined position of all adjusting devices is compensated.
• the transverse controllers Q i2 and Q 34 and the longitudinal controller L are characterized in that they are superimposed on the position control and generate a position correction value.
• the Integ ⁇ ralanteil thereby yields the stationary correction setpoint. This is itself again limited to prevent too much "charging" of the I-share.
• FIG. 6 shows one of the position controllers S1 to S4 in detail.
• the position controller has an error controller 24 in addition to the actual position controller 26.
• the error controller 24 forms a redundant system with the position controller 26. In the normal case, only the position controller 26 is effective.
• the position controller has an error signal 22.
• the error signal 22 is fed via an inverter 25 to the position controller 26 to an enable input 23.
• the error signal 22 is equal to zero and is set to one by means of the inverter and thus the enable input 23 is “enabled”. If an error occurs, the error signal is blocked ⁇ 22 to one, and thus the enable input 23 of the positioning ⁇ tion regulator 26 by means of inverter 25 and be ⁇ ne function switched to inactive. Error controller 24 and position controller 26 thus operate depending on the operating state in the alternating mode. As already mentioned above, the position controller 26 "jerk ⁇ free" replaced by the error controller 24 in case of failure of a position sensor. The error controller 24 receives as a setpoint the force actual value of the respective adjacent adjusting device. Furthermore, a position controller Sl to S4 on an offset integrator 20 to compensate for a servo valve leakage current and to overcome adhesive forces in the hydraulic cylinder of the adjusting devices.
• FIG. 8 shows in detail one of the lateral regulators Q i2 or Q 34 .
• Such a cross-controller has two PI controllers with limit 40, 41. Be via a first subtraction point the actual position values x i and S x S 2 Renz forming points to two further Diffe ⁇ to which the maximum value of i is 2 tet be scarf ⁇ guided.
• FIG. 9 shows the longitudinal regulator L in detail.
• the longitudinal controller L is constructed with two PI controllers 42 and 43 analogous to the transverse controllers.
• the longitudinal controller L is prepared for evaluating all four actual position values x S i to x S 4. From the position actual values x i and S x S 2 is ti repliessstelle means of a first Mul ⁇ 44 the mean value is formed.
• the position tions actual values x S x S 3 and 4 are access site via a second multipliers 45 ⁇ averaged.
• a consistent additive interconnection of the position controller Sl to S4, the force limit controller Fl to F4, the cross-controller Qi2, Q34 and the longitudinal controller L via position correction values allows a simplified start-up of a control device for a continuous casting 2.
• the parameterization of the control ⁇ circles can be made systematically from the inside to the outside, starting with the position controllers Sl to S4 on the bank angle limit controller Q 12 , Q34 and L, the force limiting controller Fl to F4 to the error controllers 24.
• each sub-controller has a clearly definable task oh ⁇ ne mutual coupling. Even if, for example, force and oblique position limit controllers become active at the same time, this can easily be recognized by the controller outputs, because each controller can only correct in one direction.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Continuous Casting (AREA)
• Injection Moulding Of Plastics Or The Like (AREA)
• Feedback Control In General (AREA)

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• 2005
  • 2005-06-20 DE DE102005028703A patent/DE102005028703A1/de not_active Ceased
• 2006
  • 2006-05-17 AT AT06755231T patent/ATE549111T1/de active
  • 2006-05-17 EP EP06755231.5A patent/EP1893367B2/fr not_active Not-in-force
  • 2006-05-17 WO PCT/EP2006/062374 patent/WO2006136484A1/fr not_active Application Discontinuation
  • 2006-05-17 CN CN2006800220700A patent/CN101247908B/zh not_active Expired - Fee Related

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