EP4217125B1 - Device and method for rolling a metal strip - Google Patents

Description

The invention relates to a device for rolling metallic strip according to the preamble of claim 1, and a corresponding method according to claim 11.

When producing or rolling rolled goods in the form of metal strips, it is important, among other things with regard to product quality, that the roll gap between the work rolls of a rolling stand used for this purpose can be set precisely. Such a roll gap adjustment in turn requires that precise knowledge of the resulting roll gap is available during rolling or during operation of the rolling stand. For this purpose, it is known in the state of the art to determine the thickness of a metal strip between the work rolls of a rolling stand using the gauge meter principle. The thickness of the rolled goods corresponds to the distance between the barrel of the upper and lower rolls. To calculate this distance, the change in position in the adjusting cylinders is used starting from a zero point. When rolling a metal strip, the work rolls are pushed apart by the rolling force because the entire stand acts like a spring. The distance between the work rolls during rolling is therefore the sum of the movement of the adjusting cylinder and the elastic expansion of the stand. The elongation of the scaffold is calculated from the force measured in the crossheads.

In connection with the above-mentioned calculation of the elongation of a rolling stand, the stand characteristic curve is an essential component with which the stand elongation can be calculated as a function of the force in the force measuring devices (" load cells" ) used for this purpose. This means that the stand characteristic curve must be known for such a calculation of the elongation. In preparation for such a calculation, the stand characteristic curve is first determined without rolling stock by driving the work rolls directly onto one another. The function The stand characteristic curve depends on the width of the strip and the diameters of the work rolls. This function can only be measured if there is no metal strip between the work rolls and the work rolls are therefore pressed directly onto or against each other.

To roll a metal strip with a width that is smaller than the width of the work roll, the characteristic curve must be converted to the current width based on mathematical models of the stand. In other words, the stand characteristic curve must be converted for the case that a metal strip to be rolled is narrower than the barrel width, which is regularly the case. The mathematical models available for this are inaccurate or not exact, so that an exact thickness cannot be obtained. Further disadvantages of the conventional determination of the actual size of the roll gap or its actual thickness, which occurs during rolling, are that the force measurement is additionally distorted by friction forces and that wear on the rolls of the roll stand must also be recorded mathematically. This can lead to further errors in the calculation of the actual thickness of the roll gap.

According to the state of the art, it is CN108114993 and JPS62072417 It is known that when rolling metallic strips, in order to determine the roll gap, the position of backup rolls must also be determined by measurement and taken into account accordingly.

Out of WO 2007/022841 A1 A generic device for rolling metallic strip is known in which position signals to be taken into account for the position measurement between the work rolls AW and/or the backup rolls SW and/or the work roll chocks and/or the backup roll chocks are determined by means of measuring sensors, wherein a spatial position of these measuring sensors cannot be changed.

Out of JP-S62 72417 A A method for rolling metal strip is known in which the eccentricity of the support rolls of a rolling stand in particular is to be determined only before a real rolling process and thus in preparation for such a rolling process. During the rolling process itself, according to this The process then determines changing support roll positions, but without load influence and thus without frame expansion.

Accordingly, the invention is based on the object of optimizing the determination of a roll gap, which occurs between the associated work rolls during operation of a rolling stand when rolling a metallic strip, with a view to greater accuracy using simple means and then setting it to a desired target value.

The above object is achieved by a device having the features specified in claim 1, and in the same way by a method having the features of claim 11. Advantageous developments of the invention are defined in the dependent claims.

A device according to the present invention is used for rolling metal strip, in particular steel strip. Such a device comprises a rolling stand, which is formed from a pair of stands, and a pair of work rolls and an upper and lower support roll, wherein the work rolls and the support rolls are held on the rolling stand by respectively assigned chocks. A roll gap can be formed between the work rolls, wherein the work rolls can be supported by at least one respectively assigned support roll. Furthermore, the device comprises a measuring device by means of which the size of the roll gap between the work rolls can be determined. The chocks of at least one support roll are movably guided in the rolling stand and can be adjusted vertically by a hydraulic cylinder. The measuring device has at least one upper sensor with which a distance from at least one point of the upper support roll to a predetermined upper reference point can be measured, and at least one lower sensor with which a distance from at least one point of the lower support roll to a predetermined lower reference point can be measured. The measuring device comprises a force measuring device which is positioned between a chock of a support roll, preferably the lower support roll, and the rolling stand, whereby a rolling force generated by the rolling stand can be measured by means of the force measuring device. The device according to the invention further comprises a control device which is connected to the measuring device is connected in terms of signal technology, wherein the control device is equipped with at least one mathematical model with which an expansion of the rolling stand can be calculated taking into account the rolling force generated. The upper sensor and/or the lower sensor are connected to a respective associated adjustment device, wherein a position of the upper or lower sensor relative to the upper or lower support roll can be changed by means of the adjustment device. The control device is programmed in such a way that an absolute size of the roll gap and thus the resulting thickness of the rolled stock can be determined on the basis of the measured values of the upper/lower sensor with regard to the measured position of the upper/lower support roll and an expansion of the rolling stand calculated by the mathematical model, wherein this absolute value for the roll gap can be compared with a target value for the roll gap by means of the control device and on the basis of this the hydraulic cylinder can then be controlled for the vertical displacement of the associated support roll in order to thereby set the roll gap or the resulting thickness of the rolled stock in the form of the metallic strip in a controlled manner to the desired target value.

In the same way, the invention provides a method for rolling metal strip, in particular steel strip. In this method, a device according to the invention is used as explained, so that in this method a roll gap is set between work rolls that are attached to a roll stand on a device for rolling metal strip. The method according to the invention is characterized in that a distance of the upper/lower backup roll is measured at at least one point thereof from a predetermined upper/lower reference point by an upper/lower sensor and the measured values of the sensors are sent to a control device, that an elongation of the roll stand is calculated with a mathematical model with which the control device is equipped, taking into account the rolling force generated, and that by means of the control device, on the basis of the positions of the backup rolls measured by the upper sensor and the lower sensor and an elongation of the roll stand calculated by the mathematical model, an absolute size of the roll gap and thus the resulting thickness of the rolled stock is determined. By means of the control device, then this absolute value for the roll gap is compared with a target value for the roll gap and on the basis of this at least one backup roll is then adjusted, preferably hydraulically, in order to thereby adjust the roll gap or the resulting thickness of the rolled stock in the form of the metallic strip to the target value in a controlled manner.

The present invention is based on the essential finding that a movement of the support rollers or the associated support roller barrels is directly measured by suitable sensors, namely the upper and/or lower sensor, so that this movement of the support rollers no longer has to be calculated using a mathematical model. In other words, a large part of the actual expansion of the rolling stand is already determined by measurement by measuring the support roller movement and then no longer has to be calculated on the basis of a (not exact) mathematical model from the frictional force measurement. This also has the advantage that an error-prone calculation of the influence of the strip width on the deflection of the rollers, as provided for in the prior art mentioned at the beginning, is no longer necessary.

A further advantage of the invention in connection with the direct measurement of the movement of the support roll barrel is that this measurement can be used to directly measure the eccentricity of the support roll(s). This makes it possible to almost completely compensate for the eccentricity of the support roll(s) that can occur during rolling operation.

According to the invention, the direct measurement of the movement of a backup roll is carried out at at least one or more points thereof across the width of the corresponding backup roll, namely with regard to a distance from a predetermined upper or lower reference point. On this basis, an exact or absolute position of a backup roll in space is possible, also taking into account a possible deformation of the backup roll during rolling operation, and to this extent - with further consideration of the calculated expansion of the rolling stand - then a determination of an absolute value of the roll gap or the thickness of a rolled product in the form of a metallic strip between the work rolls.

• Dehnung der Ständer bzw. des Ständerpaars, welche(s) dem Walzgerüst zugeordnet sind bzw. ist,
• Abplattung der Arbeitswalzen gegen das Walzgut bzw. das metallische Band, und/oder
• Abplattung, die zwischen den Arbeitswalzen und den Stützwalzen auftritt.

At this point, it is specifically pointed out that the feature "stretching of the rolling stand" in the sense of the present invention is formed at least by the following components:

• Elongation of the stands or the pair of stands assigned to the rolling stand,
• Flattening of the work rolls against the rolling stock or the metallic strip, and/or
• Flattening that occurs between the work rolls and the backup rolls.

As explained above, such elongation of the rolling mill can be properly calculated by using a mathematical model with which the control device is equipped.

In an advantageous development of the invention, it can be provided that the control device is programmed with respect to the mathematical model in such a way that the parts of the elongation of the rolling stand which have been directly determined by measuring the positions of the support rolls are removed from the stand spring.

The sensors (i.e. upper sensor and/or lower sensor) can be mounted on the crossbeams of the rolling mill, which are mounted between the pair of columns. In concrete terms, this means that the upper sensor can be mounted on the upper crossbeam, while the lower sensor can be mounted on the lower crossbeam.

With regard to the lower sensor, it is specifically pointed out here that this can alternatively be attached to the foundation of the rolling stand. This ensures even better measurement accuracy for the lower sensor, because deformation of the foundation is also possible in the Operation of the device is not likely and thus a fixed attachment or positioning of the lower sensor is achieved.

In an advantageous development of the invention, the sensors (i.e. the upper sensor and/or the lower sensor) can each be designed as an optical sensor. In this case, the upper sensor and/or the lower sensor can be designed in the form of a laser triangulation sensor or in the form of a confocal sensor. In an advantageous development of the invention, electromagnetic fields can be used for the sensors (i.e. the upper sensor and/or the lower sensor). In this case, it is expedient for the upper sensor and/or the lower sensor to be designed as an eddy current sensor.

With regard to the possible embodiments of the sensors mentioned above, a "mixed form" is also possible. This means that, for example, the upper sensor is designed as an optical sensor, whereby electromagnetic fields are used for the lower sensor and thus the lower sensor can be designed as an eddy current sensor. This also applies to the reverse case, i.e. design of the upper sensor as an eddy current sensor and design of the lower sensor as an optical sensor.

According to an advantageous development of the invention, a blow-out device is arranged adjacent to the upper and lower sensors, respectively, with which compressed air can be introduced into a space located between a support roller and a sensor. In this way, for example, water mist, dirt particles or similar disruptive particles can be blown away or removed from the space located between a support roller and a sensor, as a result of which the measurement accuracy for the respective sensor in relation to the measured position of an associated support roller is improved.

When correcting thickness disturbances on particularly thin materials or metallic strips, a movement of the "HGC" results (cf. Fig.3 , Fig.4 ) or the support rolls of a rolling stand largely consists of compensating for the changing stand elongation. In simple terms, the elongation is determined by the following equation: $$\mathrm{strain}=\frac{\mathrm{measured}\mathrm{Rolling\; force}}{\mathrm{Scaffold\; spring}}$$

In words, the elongation is determined - to put it simply - from the quotient of the measured rolling force and the stand spring. Based on the fact that parts of the elongation of the rolling stand, in particular a deformation or movement of the support rollers, are now determined directly by measurement using the sensors mentioned, these measured parts of the elongation can be removed from the stand spring, which then becomes larger. As a result of the stand spring being larger, the calculated elongation is smaller. This also reduces the influence of friction on the measured (rolling) force. Percentage errors in the stand spring also result in smaller elongation errors.

In an advantageous development of the invention, the control device can be equipped with a mathematical compensation model with which the thermal properties and wear of the work rolls and/or the backup rolls can be calculated. In this way, it is possible to directly determine the wear and temperature-related change in the diameter of the work rolls and/or the backup rolls during the rolling process by calculation. This can be taken into account for the hydraulic adjustment of at least one backup roll in order to adjust the roll gap or the resulting thickness of the rolled material in the form of the metallic strip to the target value in a controlled manner. This makes it possible, on the one hand, to improve the accuracy of the set roll gap during operation of the device according to the invention or when carrying out the method according to the invention and, on the other hand, to gain knowledge of the current state of wear of the work rolls and/or the backup rolls in order to then only replace the respective rolls when actually needed (and not time-dependent, i.e. after predetermined rigid points in time).

Fig. 1

eine vereinfachte Ansicht einer erfindungsgemäßen Vorrichtung zum Walzen von metallischem Band,

Fig. 2

eine vereinfachte Ansicht einer Vorrichtung zum Walzen von metallischem Band gemäß einer weiteren Ausführungsform der Erfindung,

Fig. 3

eine vereinfachte Ansicht der erfindungsgemäßen Vorrichtung von Fig. 1 bzw. Fig. 2, ergänzt um die Symbolik eines Regelkreises einer zugehörigen Regelungsvorrichtung, und

Fig. 4

eine vereinfachte Ansicht der Vorrichtung von Fig. 1 bzw. Fig. 2 gemäß einer weiteren Ausführungsform der Erfindung, ergänzt um die Symbolik eines Regelkreises einer zugehörigen Regelungsvorrichtung.

Further details and advantages of the invention emerge from the following embodiments explained with reference to figures. They show:

Fig.1

a simplified view of an apparatus according to the invention for rolling metallic strip,

Fig.2

a simplified view of an apparatus for rolling metallic strip according to another embodiment of the invention,

Fig.3

a simplified view of the device according to the invention of Fig.1 or. Fig.2 , supplemented by the symbolism of a control loop of an associated control device, and

Fig.4

a simplified view of the device of Fig.1 or. Fig. 2 according to a further embodiment of the invention, supplemented by the symbolism of a control loop of an associated control device.

Below, with reference to the Fig. 1-4 preferred embodiments of a device 10 according to the invention and an associated method for rolling metal strip are shown and explained. Identical features in the drawing are each provided with the same reference numerals. At this point, it is specifically pointed out that the drawing is only simplified and in particular is shown without a scale.

In Fig.1 a simplified view of parts of the device 10 according to the invention is shown according to a first embodiment. The device comprises a rolling stand 12 with a pair of stands 14, between which a pair of work rolls 16 are mounted in a rotatable manner. Furthermore, an upper support roll 18 and a lower support roll 19 are mounted in a rotatable manner between the stands 14 and are each arranged adjacent to a work roll 16.

The device 10 comprises in the embodiment of Fig.1 a total of four rolls, namely, as explained, two working rolls 16 and two backup rolls 18, 20. The associated rolling stand 12 of this device 10 is therefore a so-called quarto stand.

The work rolls 16 and the support rolls 18, 19 are held on the rolling stand 12 or the associated stands 14 by respective chocks E. In the Fig.1 For the sake of simplicity, only one of these chocks E is shown tightened.

The chocks E of at least one support roll 18, 20 are guided in the rolling stand so as to be movable in the vertical direction and are associated with a hydraulic cylinder 22. In the Fig.1 This is illustrated by way of example for the upper support roller 18. By actuating the hydraulic cylinder 22, it is possible to position the upper support roller 18 in a vertical direction and thereby change a distance between the two working rollers 16.

An upper crossbeam Q1 and a lower crossbeam Q2 are mounted between the stands 14 of the rolling stand 12.

The device 10 according to the invention comprises a measuring device by means of which a distance between the two work rolls 16 and thus a resulting roll gap W (cf. Fig.3 , Fig.4 ) between the work rolls can be determined.

The above-mentioned measuring device comprises in the embodiment of Fig.1 at least one upper sensor 24, which is attached to the upper crossbeam Q1, and at least one lower sensor 25, which is attached to the lower crossbeam Q2. In the illustration of Fig.1 These sensors 24, 25 are simply symbolized by an arrow each.

With the upper sensor 24, a distance of the upper support roller 18 at least at a point thereof to a predetermined upper reference point P1 can be measured. In the same way, with the lower sensor 25, a distance of the lower support roller 20 at least at a point thereof to a predetermined lower reference point P2 can be measured.

In the sense of the present invention, the above-mentioned reference points P1 and P2 form fixed points against which the movement of the support rollers 18, 20 is measured by means of the sensors 24, 25. For example, these reference points P1, P2 can be on the upper crossbeam Q1 or at the lower cross-beam Q2, as in the embodiment of Fig.1 symbolized by corresponding circles.

According to an alternative embodiment, the lower sensor 25 can be provided so that it is mounted on a foundation F (cf. Fig.1 ) of the rolling stand 12. In this case, the predetermined lower reference point P2 is then expediently also fixed to the foundation F.

In the embodiment of Fig.1 the sensors 24, 25 are each mounted in a central region of the crossbeams Q1, Q2. Accordingly, a distance of the support rollers 18, 20 in a central region thereof to the predetermined reference points P1, P2 is measured by means of the sensors 24, 25. This means that the upper sensor 24 and the lower sensor 25 are positioned with respect to a width of the rolling stand 12 in such a way that these sensors 24, 25 each measure a distance to a point in the middle of the associated support rollers 18, 20.

The measuring device further comprises a force measuring device 30, which is positioned between a chock of a support roll and the rolling stand 12. In the illustration of Fig.1 For example, an arrangement for such a force measuring device 30 is shown, which is arranged here adjacent to the respective chocks E of the lower support roll 20. By means of the force measuring device 30, it is possible to measure the rolling force generated in the rolling stand 12.

The device 10 according to the invention also comprises blow-out devices 28 (cf. Fig.1 ), which are each arranged adjacent to the upper and lower sensors 24, 25. By means of these blow-out devices 28, it is possible to introduce compressed air 29 into a space R which is located between a support roller 18, 20 and the respective sensor 24, 25. For example, such a blow-out device 28 can be designed in the form of a blower or fan. In any case, such a blow-out device 28 and the compressed air 29 generated thereby ensure that disturbing particles in the space R between the support rollers 18, 20 and the sensors 24, 25, which particles can be formed, for example, from water mist, dirt particles or the like, are effectively removed. This makes a significant contribution to improving the measuring accuracy of the sensors 24, 25 with respect to a movement of the support rollers 18, 20.

In the Fig.2 Parts of a second embodiment of the device 10 according to the invention are shown. In contrast to the first embodiment of Fig.1 In this case, a plurality of upper sensors 24 and lower sensors 25 are arranged adjacent to the upper support roller 18 and the lower support roller 20, which are operated in the same way as in the Fig.1 here are simply symbolized by arrows. For example, three sensors 24, 25 are provided along a width extension of the respective support rollers 18, 20. In this regard, it is understood that the plurality for the upper sensors 24 or lower sensors 25 can also be different from three, for example, can also be more or less than three. Otherwise, the embodiment of Fig.2 that of Fig.1 , so that in order to avoid repetition, reference is made to the explanations on Fig.1 may be referred to.

Below are the Fig.3 and 4 Further features of the device 10 according to the invention and its mode of operation as well as of a method according to the present invention are shown and explained:
The embodiment of Fig.3 corresponds to the embodiment of Fig.1 or. Fig.2 , wherein now also details of a control device 32 and the associated control circuit are shown, which are also part of the device 10 according to the invention.

First of all, for the Fig.3 It should be noted that an upper sensor 24 and a lower sensor 25 are arranged in a central area of the associated support roller 18, 19. This corresponds to the representation of Fig.1 Optionally, it can be provided that a plurality of first sensors 24 and second sensors 25 are arranged along a width of the associated support roller 18, 20, wherein these additional sensors are each are symbolized by dashed arrows. Such a plurality of sensors 24, 25 then corresponds to the representation of Fig.2 .

Fig.3 clarifies that the upper and lower sensors 24, 25 and also the force measuring device 30 are each connected to the control device 32 in terms of signals. In this way, the control device 32 receives information regarding the movements or deformations of the support rollers 18, 20 that can occur during rolling operation.

The control device 32 is equipped with a mathematical model 34, with which an elongation of the rolling stand 12 can be calculated taking into account the rolling force generated. In this case, it is important according to the invention that the measured values for the rolling force measured on the drive side of the rolling stand ("F _AS ") and for the rolling force measured on the operator side of the rolling stand ("F _BS ") are each sent to this mathematical model 34. In this regard, it is pointed out that the rolling forces generated in the Fig.3 are symbolized by corresponding block arrows positioned in the stands 14.

As already explained elsewhere above, according to the invention the elongation of the rolling stand 12 can be calculated by the mathematical model 34. In the Fig.3 In this regard, it is illustrated that during rolling operation, flattening occurs both between the metallic strip B and the work rolls 16 on the one hand and between the work rolls 16 and the adjacent backup rolls 18 on the other. These flattenings form parts of the elongation of the rolling stand 12, which is calculated by means of the mathematical model 34.

Fig.4 illustrates a third embodiment of the device 10 according to the invention. In contrast to the embodiment of Fig.3 The sensors 24, 25 are each equipped with adjustment devices 26, with which the position of a respective sensor 24, 25 can be adapted to a different diameter of an associated support roll 18, 20. This means that depending on a roll diameter of the respective support rolls 18, 20, the sensors 24, 25 can be moved vertically in or out of the roll stand 12. In other words, by means of the adjustment devices 26, a Position of the upper or lower sensor 24, 25 relative to the upper or lower support roller 18, 20 can be changed, as explained in adaptation to the respective diameter of the support rollers 18, 20. Regarding its other features, the embodiment of Fig.4 that of Fig.3 , so that in order to avoid repetition, reference is made to the explanations on Fig.3 may be referred to.

The others in Fig.3 or. Fig.4 The symbols used are as follows: - AGC: "Automatic Gauge Control" : This means an automatic adjustment of the roll gap by a corresponding vertical adjustment of at least one support roll. - HGC _AS : "Hydraulic Gauge Control" on the drive side AS: This means a control of the hydraulic cylinder 22, which is assigned to a chock E of the upper support roller 18 on the drive side AS. - s _AS : upper This means the distance by which the chock E of the support roller 18 on the drive side AS is displaced vertically when the hydraulic cylinder 22 arranged there is adjusted. - HGCss: "Hydraulic Gauge Control" on the operator side BS: This means a control of the hydraulic cylinder 22, which is assigned to a chock E of the upper support roller 18 on the operator side BS. - s _BS : This means the distance by which the chock E of the upper support roller 18 on the operator side BS is displaced vertically when the hydraulic cylinder 22 arranged there is adjusted.

The invention now works as follows:
To roll a metallic strip, it is passed between the work rolls 16 of the rolling stand 12. The work rolls 16 are spaced apart from each other so that a roll gap is formed between the work rolls 16. In the Fig.3 and 4 The metallic strip is each attracted with "B" and the roll gap, which is established between the work rolls 16 with the inclusion of the metallic strip B, is symbolized with the arrow "W".

During rolling operation, a distance of the upper support roller 18 is maintained at at least one point therefrom (cf. Fig.1 ) or at, for example, three points along the width of the support roller 18 (cf. Fig.2 ) to the predetermined upper reference point P1 by the upper sensor(s) 24, the resulting measured values then being sent to the control device 32. In the same way, a distance of the lower support roller 20 is measured at at least one point therefrom (cf. Fig.1 ) or at, for example, three points along the width of the support roller 20 (cf. Fig.2 ) to the predetermined lower reference point P2 by the lower sensor(s) 25. The measurement signals from the sensors 24, 25 are then sent to the control device 32.

Taking into account the rolling forces F _AS , Fss measured by the force measuring devices 30, an elongation of the rolling stand is calculated by the mathematical model 34 as explained.

Then, according to the method according to the invention, an absolute size of the roll gap W and thus the resulting thickness of the rolled stock is determined by means of the control device 32 on the basis of the positions of the support rolls 18, 20 measured by the upper sensor 24 and the lower sensor 25 and an elongation of the roll stand 12 calculated by the mathematical model 34, wherein by means of the control device 32 this absolute value ("h _Act ") for the roll gap W is compared with a target value ("h _REF ") for the roll gap W and on the basis of this at least the support roll 18 is then hydraulically adjusted in the vertical direction by the hydraulic cylinder 22 in order to thereby adjusting the roll gap W or the resulting thickness of the rolled material in the form of the metallic strip B to the desired value.

To carry out the above-mentioned method according to the invention, the control device 32 is set up accordingly in terms of programming. For the present invention, this means that an absolute size of the roll gap W and thus the resulting thickness of the rolled stock can be determined by means of the control device 32 on the basis of the measured values of the upper and lower sensors 24, 25 with regard to the measured position of the upper/lower support roll 18, 20 and an elongation of the rolling stand 12 calculated by the mathematical model 34. This absolute value h _Act is then compared with the target value h _REF for the roll gap W by means of the control device 32 and, on the basis of this, the hydraulic cylinder 22 is then controlled to vertically displace the associated upper support roll 18 in order to thereby set the roll gap W or the resulting thickness of the rolled stock in the form of the metallic strip B in a controlled manner to the desired target value.

To further improve the measurement accuracy, the invention may provide that the control device 32 is equipped with a mathematical compensation model which is included in the Fig.3 or 4 is each marked with "36" and labeled "compensations". Using such a mathematical compensation model 36, the thermals and wear of the work rolls 16 and/or the backup rolls 18, 20 can be calculated, and on the basis of this, the corresponding correction value can be introduced into the control system.

The present invention has been explained above with reference to possible embodiments of the device 10, which correspond to a so-called "four-high stand". Alternatively, the device 10 according to the invention can also be designed in the form of a so-called "six-high stand", wherein the rolling stand 12 is equipped with a total of four support rolls. In this case, the above explanations for the support rolls 18, 20 refer mutatis mutandis to the respective outer support rolls of a six-high stand in order to achieve the result and in In the same way, the roll gap W or the resulting thickness of the rolled material in the form of the metallic strip B can be adjusted to a desired setpoint.

List of reference symbols

10

contraption

12

Rolling mill

14

Stand

16

Working roll(s)

18

upper support roller

20

lower support roller

22

Hydraulic cylinder

24

upper sensor

25

lower sensor

26

Adjustment device (for upper sensor 24/lower sensor 25)

28

Blow-out device

29

Compressed air

30

Force measuring device

32

Control device

34

mathematical model

36

mathematical compensation model

B

metallic band

E

Insert(s)

F

foundation

hREF

Setpoint (for the roll gap W)

Q1

upper crossbar

Q2

lower crossbar

P1

predetermined upper reference point

P2

predetermined lower reference point

R

Space (between a support roller 18, 20 and a sensor 24, 25)

W

Roll gap

Claims (17)

1. Device (10) for rolling metallic strip (B), comprising

   a roll stand (12) formed from a pair of housings (14),

   a pair of work rolls (16) and an upper and a lower backing roll (18; 20), wherein the work rolls (16) and the backing rolls (18; 20) are each mounted at the roll stand (12) by respectively associated chocks (E) and wherein a rolling gap can be formed between the work rolls (16) and the work rolls (16) can be supported by at least one respectively associated backing roll (18; 20), and

   a measuring device by means of which the size of the rolling gap (W) between the work rolls (16) can be determined,

   wherein the chocks (E) are movably guided by at least one backing roll (18; 20) in the roll stand (12) and are vertically adjustable by a hydraulic cylinder (22),

   wherein the measuring device comprises a force measuring device (30) positioned between a chock (E) of a backing roll (18; 20) and the roll stand (12), wherein a rolling force generated by the roll stand (12) can be measured by means of the force measuring device (30), wherein the measuring device comprises at least one upper sensor (24) by which a spacing from at least one point of the upper backing roll (18; 20) from a predetermined upper reference point (P1) can be measured,

   wherein a regulating device (32) is provided, which is in signal-connection with the measuring device, wherein the regulating device (32) is equipped at least with a mathematical model (34) by which a stretching of the roll stand (12) can be calculated with consideration of the rolling force produced, wherein the regulating device (32) is arranged in such a way in terms of program that an absolute magnitude of the rolling gap (W) and thus the resulting thickness of the rolling material are determinable on the basis of the measurement values of the upper sensor (25) with respect to the measured position of the upper backing roll (18; 20) and a stretching of the roll stand (12) calculated by the mathematical model (34), wherein this absolute value for the rolling gap (W) can be compared with a target value (h_REF) for the rolling gap (W) by means of the regulating device (32) and the hydraulic cylinder (22) for vertical displacement of the associated backing roll (18; 20) can then be activated on the basis thereof so as to thereby set the rolling gap (W) or the resulting thickness of the rolling material in the form of the metallic strip (B) in regulated manner to the desired target value (h_REF),

   characterised in that

   the measuring device comprises at least one lower sensor (25) by which a spacing of at

   least one point of the lower backing roll (18; 20) from a predetermined lower reference point (P2) can be measured,

   the upper sensor (24) and/or the lower sensor (25) is or are connected with a respectively associated adjusting device (26), wherein a position of the upper or lower sensor (25) relative to the upper or lower backing roll (18; 20) is variable by means of the adjusting device (26) and

   the regulating device (32) is so arranged in terms of program that an absolute magnitude of the rolling gap (W) and thus the resulting thickness of the rolling material can be determined on the basis of the measurement values of the lower sensor (25) with respect to the measured position of the lower backing roll (18; 20) and a stretching of the roll stand (12) calculated by the mathematical model (34), wherein this absolute value for the rolling gap (W) can be compared with a target value (h_REF) for the rolling tap (W) by means of the regulating device (32) and the hydraulic cylinder (22) for the vertical displacement of the associated backing roll (18; 20) is then activatable on the basis thereof so as to thereby set the rolling gap (W) or the resulting thickness of the rolling material in the form of the metallic strip (B) in regulated manner to the desired target value (h_REF).
2. Device (10) according to claim 1, characterised in that the regulating device (32) is equipped with a mathematical compensation model (36) by which thermal state and wear of the work rolls (16) and/or the backing rolls (18; 20) can be calculated.
3. Device (10) according to claim 1 or 2, characterised in that the roll stand (12) comprises an upper crossbeam (Q1) on which the upper sensor (24) is mounted.
4. Device (10) according to any one of claims 1 to 3, characterised in that the roll stand (12) comprises a lower crossbeam (Q2) on which the lower sensor (25) is mounted.
5. Device (10) according to any one of claims 1 to 3, characterised in that the lower sensor (25) is mounted on a foundation (F) of the roll stand (12).
6. Device (10) according to any one of the preceding claims, characterised in that the upper sensor (24) and/or the lower sensor (25) is or are so positioned with respect to the width of the roll stand (12) that a spacing from a point in the centre of the backing roll (18; 20) is measured by this sensor (24; 25).
7. Device (10) according to any one of the preceding claims, characterised in that the upper sensor (24) and/or the lower sensor (25) has or each have the form of an optical sensor, preferably in that the upper sensor (24) and/or the lower sensor (25) is or each are in the form of a laser triangulation sensor or in the form of a confocal sensor.
8. Device (10) according to any one of the preceding claims, characterised in that electromagnetic fields are used for the upper sensor (24) and/or the lower sensor (25), preferably in that the upper sensor (24) and/or the lower sensor (25) has or each have the configuration of an eddy current sensor.
9. Device (10) according to claim 7 or 8, characterised in that a respective blowing-free device (28) by which compressed air can be introduced into a space (R) present between a backing roll (18; 20) and a sensor (24; 25) is arranged adjacent to each of the upper and lower sensors (25).
10. Device (10) according to any one of the preceding claims, characterised in that a respective plurality of upper sensors (24) and lower sensors (25) are provided adjacent to each of the upper and lower backing rolls (18; 20) and along the width of an associated backing roll (18; 20).
11. Method of rolling metallic strip (B), in which a rolling gap (W) is set between work rolls (16), which are mounted on a roll stand (12), by a device (10) according to any one of claims 1 to 10,

    wherein a spacing of an upper/lower backing roll (18; 20) at at least one respective point thereof from a predetermined upper/lower reference point (P1; P2) is measured by an upper/lower sensor (25) and the measurement values of the sensors are communicated to a regulating device (32),

    wherein a stretching of the roll stand (12) is calculated by a mathematical model (34), with which the regulating device (32) is equipped, with consideration of the rolling force produced, and

    wherein an absolute magnitude of the rolling gap (W) and thus the resulting thickness of the rolling material are determined by means of the regulating device (32) on the basis of the positions, which are measured by the upper sensor (24) and the lower sensor (25), of the backing rolls (18; 20) and a stretching, which is calculated by the mathematical model (34), of the roll stand (12), wherein this absolute value for the rolling gap (W) is compared with a target value (h_REF) for the rolling gap (W) by means of the regulating device (32) and at least one backing roll (18; 20) is then adjusted, preferably hydraulically, on the basis thereof so as to thereby set the rolling gap (W) or the resulting thickness of the rolling material in the form of the metallic strip (B) in regulated manner to the target value (h_REF).
12. Method according to claim 11, characterised in that the regulating device (32) is so arranged in terms of program with respect to the mathematical model (34) that the components of the stretching of the roll stand (12) which were directly determined by means of the measurement of the positions of the backing rolls (18; 20) are removed from the stand spring characteristic.
13. Method according to claim 11 or 12, characterised in that the regulating device (32) is equipped with a mathematical compensation model (36) by which thermal state and wear of the work rolls (16) and/or the backing rolls (18, 20) are calculated, wherein these variables are taken into consideration for the hydraulic adjustment of at least one backing roll (18; 20) so as to thereby set the rolling gap (W) or the resulting thickness of the rolling material in the form of the metallic strip (B) in regulated manner to the target value.
14. Method according to any one of claims 11 to 13, characterised in that a position of the upper/lower backing roll (18; 20) is measured by a plurality of upper/lower sensors (24; 25) respectively arranged along a width of the respective backing roll (18; 20).
15. Method according to any one of claims 11 to 14, characterised in that the upper sensor (24) and/or the lower sensor (25) has or each have the configuration of an optical sensor.
16. Method according to any one of claims 11 to 15, characterised in that electromagnetic fields are used for the upper sensor (24) and/or the lower sensor (25).
17. Method according to claim 15 or 16, characterised in that a respective blowing-free device (28) by which compressed air can be introduced into a space (R) present between a backing roll (18; 20) and a sensor (24; 25) is provided adjacent to each of the sensors.

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