EP4204166B1 - Flatness-measuring device, hot-rolling mill, and method for operating a flatness-measuring device - Google Patents

Description

The invention relates to a flatness measuring device for measuring a flatness of a hot strip within a hot rolling mill, having at least one inlet-side deflection roller for contacting a first large side of the hot strip, at least one outlet-side deflection roller for contacting the first large side of the hot strip and at least one with respect to a strip running direction of the hot strip between the inlet side Deflection roller and the outlet-side deflection roller, which can be adjusted against a second large side of the hot strip opposite the first large side of the hot strip and serves as a flatness measuring roller. The invention also relates to a hot rolling mill with at least one flatness measuring device.

The invention further relates to a method for operating a flatness measuring device for measuring a flatness of a hot strip within a hot rolling mill, wherein the flatness measuring device has at least one inlet-side deflection roller for contacting a first large side of the hot strip, at least one outlet-side deflection roller for contacting the first large side of the hot strip and at least one relative a strip running direction of the hot strip between the inlet-side deflection roller and the outlet-side deflection roller, which can be adjusted against a second large side of the hot strip opposite the first large side of the hot strip and serves as a flatness measuring roller.

If a metal strip is guided over a longer distance in a system, it is particularly important that processes and/or devices are in place that make it possible to control the movement of the metal strip. These methods and/or devices influence the band running in such a way that the metal band is prevented from running laterally. If the lateral movement was not prevented, the metal strip would hit the side boundaries of the system and be damaged. In the worst case, this leads to a disruption in the process and even a belt break, which can be seen as a serious accident in such an often continuous process, which causes considerable costs.

When measuring flatness in a hot rolling mill for steel, a possible position for the measuring device used for this purpose is between the cooling section and a driver roller of the hot rolling mill. Since flatness measurement requires a wrap around a flatness measuring roller, which deflects the metal strip and can therefore also be referred to as a deflection roller in the sense of the present invention, the measuring roller must be immersed in the metal strip. As soon as the measuring roller is immersed in the metal strip, a configuration of three deflection rollers is created, namely an inlet-side roller table roller as a deflection roller, the measuring roller as a deflection roller and the outlet-side roller table roller as a deflection roller.

This configuration results in a great risk of tape wandering. In particular, metal strips with a thin strip tend to have an unstable strip path in the lateral direction. In these cases, flatness measurement using a measuring roller is practically no longer possible. The wear on the side guides of the system is significantly increased, the winding quality of band coils is significantly worsened and the risk of band lifts or band breaks is increased. The sideways movement of the metal strip also creates a tension distortion, which causes a disruption in the flatness measurement. This disturbance makes it impossible to measure a linear flatness error.

Convex deflection rollers and deflection rollers mounted on swivel frames are known from continuous processes for the treatment of metal strips, such as in continuous annealing furnaces and galvanizing lines. The cambered deflection rollers lead to a centering effect due to the tension redistribution created by the cambering. The swivel frames are controlled by a regulation that is based on a measured band center position. When cold rolling longitudinally split hot strip, the problem arises that, due to the conical coil structure, the hot strip also shows a strong tendency to run sideways. This disruption to the rolling process is counteracted by pivoting the deflection roller arranged directly in front of a reel. This measure allows the belt to be brought back into a centered belt path.

When using these known methods, it is assumed that the bands are permanently under tension. The completely different clamping situation during hot rolling involves long stretches in which the strip is subject to guidance with little or no strip tension. This clamping situation compared to a deflection roller that is common in cold rolling requires devices and methods that can control the strip with a triple deflection. In addition, due to the significantly longer clamping lengths between the last roll stand and the flatness measuring roll, and the associated large dead time, the conventional control methods fail.

Information on strip running control when winding and unwinding a metal strip as well as in endless systems based on optical strip center measurement can be found at the link https://www.emg-automation.com/automation/bandlaufregelen/. However, the means used for this purpose cannot be used in a roller table of a hot rolling mill. In addition, such means There is also no possibility of compensating for a disruption in a flatness measurement.

JP 2012 206 132 A discloses a rolling mill having rolls that roll a rolled material, a winding roll disposed downstream of the rolls and winding up the rolled material, and a deflection roll that changes a feed direction of the rolling material rolled by the rolls to feed it to the winding roll lead. When performing rolling using the rolling mill, a condition of surface defect generated in the rolled material wound on the winding roll is detected. One end of the deflection roller is moved in a direction perpendicular to the central axis of the deflection roller based on the detected state of the surface defect, so that the generation of the surface defect can be suppressed.

EP 3 097 990 A1 discloses a cold rolling apparatus that heats a sequentially transferred steel sheet using a heater and sequentially cold-rolls the steel sheet after heating by using a cold rolling mill. The cold rolling device includes a meander motion correcting device disposed on an upstream side of the heater in a transferring direction of the steel sheet and configured to correct a meander motion of the steel sheet transferred toward the heater. In addition, the cold rolling device includes a meandering suppression device disposed between the heater and the cold rolling mill and configured to suppress meandering motion of the steel sheet associated with cold rolling of the steel sheet by using the cold rolling mill. Further, the cold rolling device includes a controller configured to control the meander movement correcting device to perform a meander movement correcting operation to correct the meander movement of the steel sheet transferred to the heater. In addition, the control is set up, the meandering movement suppression device to perform a meandering suppression operation to suppress the meandering of the steel sheet associated with the cold rolling of the steel sheet. The controller controls the meander motion suppression device to perform the meander motion suppression operation at a timing when the controller controls the meander motion correction device to perform the meander motion correction operation.

The EP 0906 797 A1 discloses a flatness measuring device and a method for operating a flatness measuring device for measuring a flatness of a hot strip within a hot rolling mill, wherein the flatness measuring device has at least one inlet-side deflection roller for contacting a first broad side of the hot strip, at least one outlet-side deflection roller for contacting the first broad side of the hot strip and at least one with respect to a strip running direction of the hot strip between the inlet-side deflection roller and the outlet-side deflection roller, which can be adjusted against a second broad side of the hot strip opposite the first broad side of the hot strip and serves as a flatness measuring roller.

DE 195 24 729 A1 discloses a device for rolling strips which have a non-uniform thickness and/or length distribution across their width. The device has at least one control roller arranged on the inlet and/or outlet side of the rolling mill, which can be pivoted in its position relative to the strip, means for detecting the tension distribution across the width of the strip and a control device which, from the detected tension distribution, provides control signals for control devices Pivoting of the control roller is determined.

One object of the invention is to prevent a hot strip from running laterally in a hot rolling mill during a flatness measurement on the hot strip.

This task is solved by the independent patent claims. Advantageous refinements are shown in the following description, the dependent patent claims and the figures, whereby these refinements, taken alone or in combination of at least two of these refinements with each other, can represent a further, in particular preferred or advantageous aspect of the invention. Configurations of the flatness measuring device can correspond to configurations of the method, and vice versa, even if this is not explicitly pointed out below in individual cases.

A flatness measuring device according to the invention for measuring a flatness of a hot strip within a hot rolling mill has at least one inlet-side deflection roller for contacting a first large side of the hot strip, at least one outlet-side deflection roller for contacting the first large side of the hot strip, at least one with respect to a strip running direction of the hot strip between the inlet-side deflection roller and the middle deflection roller arranged on the outlet-side deflection roller, which can be adjusted against a second large side of the hot strip opposite the first large side of the hot strip and serves as a flatness measuring roller, at least one detection device for detecting an actual position of the hot strip and at least one adjusting device connected to the detection device and at least one of the deflection rollers, which is set up is to vary an angle between a longitudinal central axis of the deflection roller connected to the adjusting device and a longitudinal axis of the flatness measuring device running transversely to the deflection rollers depending on a deviation of the actual position of the hot strip from a predetermined target position of the hot strip.

The detection device for detecting an actual position of the hot strip can be arranged close to the middle deflection roller. In particular, the detection device for detecting an actual position of the hot strip can be arranged before or after the middle deflection roller. Preferably, the detection device for detecting an actual position of the hot strip is arranged directly on the middle deflection roller. The detection device for detecting an actual position of the hot strip is preferably arranged no further than 1 m away from the middle deflection roller. The detection device can be set up to determine the position of the hot strip from measured values of the flatness measurement and / or from tension measurement signals from load cells arranged under bearings of one of the deflection rollers.

Due to a large clamped length of the hot strip between a flatness measuring device and a finishing train of a hot rolling mill, the strip path becomes very unstable when the middle deflection roller used as a flatness measuring roller is immersed, so that the hot strip could easily run sideways. This can be reliably prevented with the flatness measuring device according to the invention by influencing the strip run by varying the angle between the longitudinal central axis of the deflection roller connected to the adjusting device and the longitudinal axis of the flatness measuring device depending on the current deviation of the actual position of the hot strip from a predetermined target position of the hot strip or is corrected. The application of the invention makes it possible in particular to check the strip center position when measuring flatness in the exit roller table of a hot rolling mill. Without the invention, the hot strips would move so much laterally during the flatness measuring process that the process would have to be stopped. This problem occurs particularly in the case of hot strips with a thin strip thickness. However, these hot strips are particularly interesting for flatness measurement.

When measuring flatness, for example, a tensile stress distribution in the hot strip can be measured.

The inlet-side deflection roller for contacting the first large side, for example the underside, i.e. H. The lower broad side of the hot strip can in particular be a roller of a roller table, via which the rolled hot strip can be fed to the flatness measuring device. Conversely, the term “upper broadside” means the opposite mainside, i.e. H. the upper broad side of the hot strip.

The outlet-side deflection roller for contacting the first large side, for example the underside, of the hot strip can in particular be a roller table roller of a roller table, via which the hot strip measured with the flatness measuring device can be fed to a drive roller unit of the hot rolling mill in front of a reel of the hot rolling mill.

The middle deflection roller serves as a flatness measuring roller. The middle deflection roller is arranged between the inlet-side deflection roller and the outlet-side deflection roller, in particular in a plan view of one of the large sides of the hot strip with respect to the strip running direction of the hot strip. In order to be able to carry out a flatness measurement, the middle deflection roller can be adjusted against the second large side, for example the top side, of the hot strip opposite the first large side of the hot strip. For this purpose, the middle deflection roller is connected to an actuator for turning on the middle deflection roller and evaluation electronics for evaluating mechanical loads on the middle evaluation electronics.

The detection device for detecting the actual position of the hot strip can, for example, have at least one optical sensor, for example a camera. In addition, the detection device can have evaluation electronics for processing signals from the optical sensor. The Detection device can, for example, be set up to detect an actual position of a strip center of the hot strip as the actual position of the hot strip on the inlet side.

The adjusting device can, for example, be connected solely to the inlet-side deflection roller in order to be able to vary the position of this deflection roller according to the invention, whereby an inventive control and / or regulation of the actual position or strip center position of the hot strip can take place. By means of the adjusting device, the inlet-side deflection roller can be pivoted, for example, in a horizontal plane in order to be able to vary the angle between the longitudinal center axis of the inlet-side deflection roller and the longitudinal axis of the flatness measuring device according to the invention. The variation of the angle between the longitudinal central axis of the inlet-side deflection roller and the longitudinal axis of the flatness measuring device can correspond to a variation of an angle between the longitudinal central axis of the deflection roller and a longitudinal axis of the hot rolling system, the longitudinal axis of the hot rolling system being defined by two points, namely the center of a roll gap of the last Roll stand of the finishing train and the middle of a clamping gap of the drive roller unit in front of the reel. The angle between the longitudinal central axis of the inlet-side deflection roller and the longitudinal axis of the flatness measuring device can, for example, be in a range of +/- 10 mm/m, preferably in a range of +/- 15 mm/m, particularly preferably in a range of +/- 50 mm/m, lie.

Alternatively, the adjusting device can be connected solely to the outlet-side deflection roller or the middle deflection roller in order to be able to move the respective deflection roller according to the invention for controlling and / or regulating the belt run. Alternatively, the adjusting device can be connected to two of the deflection rollers or to all of the deflection rollers in order to be able to move the deflection rollers according to the invention to control and / or regulate the belt run. To carry out the displacement of two or more deflection rollers, they can be done using one common actuator of the adjustment device or with separate or own actuators of the adjustment device can be relocated individually.

The angle of the respective displaceable or pivotable deflection roller, which can be varied according to the invention, is given between the longitudinal central axis of the respective deflection roller, which is oriented transversely to the strip running direction, and the longitudinal axis of the flatness measuring device which runs transversely to the deflection rollers, the longitudinal axis of the flatness measuring device being able to be identical to the longitudinal axis of the hot rolling mill. The angle can in particular be in a horizontal plane.

The adjusting device can have at least one controller, by means of which the angle between the longitudinal central axis of the respective deflection roller and the longitudinal axis of the flatness measuring device can be varied depending on the deviation of the actual position of the hot strip from the predetermined target position of the hot strip. The controller can have a center controller which is set up to determine a target value for a pivot position of the respective deflection roller from the deviation of the actual position of the hot strip from the specified target position of the hot strip or a corresponding difference between the actual position of the hot strip and the specified target position of the hot strip , by using which the strip running of the hot strip can be corrected. The center controller can be designed as a PI controller.

According to an advantageous embodiment, the adjusting device is set up to determine an actual position of the deflection roller connected to the adjusting device, to determine a desired position of this deflection roller from the deviation of the actual position of the hot strip from the predetermined target position of the hot strip, and a target adjustment speed value for adjusting the angle between the longitudinal central axis of this deflection roller and the longitudinal axis of the flatness measuring device depending on a deviation of the actual position of this deflection roller from the target position of this deflection roller. Through this The adjustment speed at which the respective deflection roller is pivoted can be quickly and individually adapted to the current situation with regard to the belt running. For this purpose, the adjusting device can have a swivel controller which is set up to determine an adjustment speed value from the deviation of the actual position of the deflection roller connected to the adjusting device from the target position of this deflection roller or a corresponding difference between the actual position of this deflection roller and the target position of this deflection roller which the strip run of the hot strip can be corrected. The swivel controller can be designed as a pure P controller.

According to a further advantageous embodiment, the adjusting device is set up to determine a speed of a sideways movement of the hot strip and to determine the target adjustment speed value depending on the speed of the sideways movement of the hot strip. For this purpose, the adjusting device can have a differential controller which is set up to determine an additional value for the pivoting speed of the deflection roller connected to the adjusting device from the speed of the inlet-side sideways movement of the hot strip, whereby this additional value and the adjusting speed determined by the pivoting controller can be added up in order to achieve this To generate a target adjustment speed value for controlling an actuator of the adjustment device.

According to a further advantageous embodiment, the adjusting device is set up to pivot the deflection roller connected to the adjusting device and/or at least one other deflection roller connected to the adjusting device in a plane which is arranged perpendicular to the longitudinal axis of the flatness measuring device, and to pivot the respective deflection roller in the plane depending on an angle value by which the angle between the longitudinal center axis of the respective deflection roller and the longitudinal axis of the flatness measuring device can be varied by means of the adjusting device. For example, if the inlet side If the deflection roller for tape running control is varied by an angle between the longitudinal center axis of this deflection roller and the longitudinal axis of the flatness measuring device, the relatively small distance of this deflection roller from the middle deflection roller results in impairments to the flatness measurement due to a change in the geometry of the clamping of the hot strip in the flatness measuring device. In order to be able to compensate for such a disturbance, the deflection roller and / or at least one further deflection roller is pivoted or displaced in the plane arranged perpendicular to the longitudinal axis of the flatness measuring device, for example vertical, in such a way that the change in the geometry of the clamping of the hot strip in the flatness measuring device is balanced.

For this purpose, a length difference Δ l between the strip edges of the hot strip can be determined by means of the adjusting device due to a pivoting amount SB of the deflection roller, the longitudinal central axis of which is varied by an angle between the longitudinal central axis of this deflection roller and the longitudinal axis of the flatness measuring device. The expression Δ l = f ( SB , geometry ) can apply to the length difference Δ l, whereby the length difference Δ l is a function of the swivel amount SB and the clamping geometry. Based on this difference in length, a pivoting amount SM of the deflection roller used to compensate for the change in the clamping geometry can be determined in the vertical direction by means of the adjusting device, which leads to a minimization of the disturbance caused by the horizontal pivoting movement of the deflection roller, the longitudinal central axis of which is about the angle between the longitudinal central axis of this deflection roller and the longitudinal axis of the flatness measuring device is varied. The expression SM = f (Δ l = 0, geometry ) can apply to the swivel amount SM, whereby the swivel amount SM is a function of the length difference Δ l and the clamping geometry. This swivel amount SM can be transferred and adjusted directly or via a ramp to an actuator of the adjusting device. The calculation of the swivel amount SM can also be done directly, where SM = f ( SB , geometry ) can apply, so the swivel amount SM is a function the swivel amount SB and the clamping geometry can be. The connection between the pivoting amount SM and the pivoting amount SB can be established in such a way that the clamped length of the hot strip over the entire flatness measuring device on an operating-side strip edge is equal to that on the drive side. To improve the online capability or to simplify the use of compensation in an online system, the calculation of the relationship between the swivel amount SM and the swivel amount SB can be done offline and the relationship can be stored in the form of a table in the adjustment device. The pivoting movement to compensate for the change in the geometry of the clamping of the hot strip in the flatness measuring device can be carried out solely with the inlet-side deflection roller, the outlet-side deflection roller or the middle deflection roller. Alternatively, this compensation can be done using two of the deflection rollers or all of the deflection rollers. To carry out the displacement of two or more deflection rollers, they can be displaced individually using a common actuator of the adjusting device or with separate or separate actuators of the adjusting device.

According to a further advantageous embodiment, the deflection roller connected to the adjusting device is arranged to be displaceable about an axis of rotation running perpendicular to an incoming strip section of the hot strip, the axis of rotation passing through a center of the deflection roller connected to the adjusting device or offset from the center with respect to the longitudinal axis of this deflection roller this deflection roller is arranged. In particular, the axis of rotation can be arranged in the middle of the respective deflection roller or offset to the operating side or the drive side.

According to a further advantageous embodiment, the adjusting device has at least one electromechanical drive connected to the deflection roller connected to the adjusting device, for example Spindle drive, or at least one hydraulic actuating cylinder connected to this deflection roller.

According to a further advantageous embodiment, the flatness measuring device has at least one holding frame on which the inlet-side deflection roller, the outlet-side deflection roller and / or the middle deflection roller are or are rotatably mounted, the adjusting device being connected to the respective deflection roller via the holding frame and the holding frame can be moved together with the respective deflection roller associated with it. Two of the deflection rollers or all of the deflection rollers can also be mounted on the holding frame in order to be able to move these deflection rollers together to optimize the flatness measurement.

According to a further advantageous embodiment, at least one deflection roller has a bale surface with increased roughness. In this way, the control effect of the respective deflection roller on the belt run can be improved.

According to a further advantageous embodiment, at least one deflection roller has a wear-resistant bale coating. The bale coating can be, for example, a ceramic coating, such as a tungsten carbide coating.

According to a further advantageous one, the detection device is arranged and set up to detect an actual position of the hot strip on the inlet side or an actual position of the hot strip on the outlet side. An actual position of the hot strip on the inlet side is to be understood as meaning an actual position of the hot strip before the hot strip entering the flatness measuring device comes into contact with the deflection roller on the inlet side. An actual position of the hot strip on the outlet side is to be understood as meaning an actual position of the hot strip after the hot strip leaving the flatness measuring device has been deflected by means of the deflection roller on the outlet side.

A hot rolling plant according to the invention has at least one flatness measuring device according to one of the above-mentioned configurations or a combination of at least two of these configurations with one another. The advantages mentioned above with regard to the flatness measuring device are associated with the hot rolling mill.

According to a method according to the invention for operating a flatness measuring device for measuring a flatness of a hot strip within a hot rolling mill, the flatness measuring device having at least one inlet-side deflection roller for contacting a first large side of the hot strip, at least one outlet-side deflection roller for contacting the first large side of the hot strip and at least one with respect to a strip running direction of the hot strip between the inlet-side deflection roller and the outlet-side deflection roller, which can be adjusted against a second large side of the hot strip opposite the first large side of the hot strip and serves as a flatness measuring roller, an actual position of the hot strip is detected and an angle between a longitudinal central axis of at least one deflection roller and a longitudinal axis of the flatness measuring device running transversely to the deflection rollers varies depending on a deviation of the actual position of the hot strip from a predetermined target position of the hot strip.

The advantages mentioned above with regard to the flatness measuring device are associated with the method. In particular, the flatness measuring device can be used according to one of the above-mentioned embodiments or a combination of at least two of these embodiments together to carry out the method.

According to an advantageous embodiment, an actual position of the deflection roller, the position of which can be varied accordingly, is determined from the deviation of the actual position of the Hot strip determines a target position of this deflection roller from the predetermined target position of the hot strip and a target adjustment speed value for adjusting the angle between the longitudinal central axis of this deflection roller and the longitudinal axis of the flatness measuring device is determined depending on a deviation of the actual position of this deflection roller from the target position of this deflection roller. The advantages mentioned above with reference to the corresponding design of the flatness measuring device are correspondingly associated with this configuration.

According to a further advantageous embodiment, a speed of a sideways movement of the hot strip is determined and the target adjustment speed value is determined depending on the speed of the sideways movement of the hot strip. The advantages mentioned above with reference to the corresponding design of the flatness measuring device are correspondingly associated with this configuration.

According to a further advantageous embodiment, the deflection roller, the position of which can be varied accordingly, or at least one other deflection roller is pivoted in a plane which is arranged perpendicular to the longitudinal axis of the flatness measuring device, the pivoting of the respective deflection roller in the plane being carried out as a function of an angular value, by which the angle between the longitudinal center axis of the respective deflection roller and the longitudinal axis of the flatness measuring device can be varied. The advantages mentioned above with reference to the corresponding design of the flatness measuring device are correspondingly associated with this configuration.

Figur 1A:

eine schematische Draufsicht eines Ausführungsbeispiels für eine erfindungsgemäße Planheitsmessvorrichtung;

Figur 1B:

eine schematische Seitenansicht der in Figur 1A gezeigten Planheitsmessvorrichtung; und

Figur 2:

ein Ablaufdiagramm eines Ausführungsbeispiels für ein erfindungsgemäßes Verfahren.

In the following, the invention will be explained by way of example with reference to the attached figures using preferred embodiments, whereby the features explained below can represent an advantageous or further developing aspect of the invention both individually and in combination of at least two of these features. It shows:

Figure 1A:

a schematic top view of an exemplary embodiment of a flatness measuring device according to the invention;

Figure 1B:

a schematic side view of the in Figure 1A flatness measuring device shown; and

Figure 2:

a flowchart of an exemplary embodiment of a method according to the invention.

In the figures, identical or functionally identical components are provided with the same reference numbers. Repeated description of these components may be omitted.

Figure 1A shows a schematic top view of an exemplary embodiment of a flatness measuring device 1 according to the invention for measuring a flatness of a hot strip 2 within a hot rolling mill, not shown.

The flatness measuring device 1 has an inlet-side deflection roller 3 for contacting a first large side in the form of an underside of the hot strip 2. The inlet-side deflection roller 3 is part of an inlet-side roller table, of which two further guide rollers 4 are shown. The inlet-side deflection roller 3 can have a bale surface with increased roughness. In addition, the inlet-side deflection roller 3 can have a wear-resistant bale coating, not shown.

In addition, the flatness measuring device 1 has an outlet-side deflection roller 5 for contacting the first large side in the form of the underside of the hot strip 2. The outlet-side deflection roller 5 is part of an outlet-side roller table, of which a further guide roller 4 is shown. The outlet-side deflection roller 5 can have a bale surface with increased roughness. In addition, it can outlet-side deflection roller 5 have a wear-resistant bale coating, not shown.

Furthermore, the flatness measuring device 1 has a middle deflection roller 7 which is arranged with respect to a strip running direction 6 of the hot strip 2 between the inlet-side deflection roller 3 and the outlet-side deflection roller 5 and can be adjusted against a second large side opposite the first large side of the hot strip 2 in the form of an upper side of the hot strip 2. The middle deflection roller 7 serves as a flatness measuring roller and can have a bale surface with increased roughness. In addition, the middle deflection roller 7 can have a wear-resistant bale coating, not shown.

In addition, the flatness measuring device 1 has a detection device 8 for detecting an actual position of the hot strip 2. The detection device 8 can have at least one optical sensor, not shown, for example a camera.

The flatness measuring device 1 also has an adjusting device 9 connected to the detection device 8, the inlet-side deflection roller 3 and the middle deflection roller 7. The adjusting device 9 is set up to determine an angle α between a longitudinal central axis 10 of the inlet-side deflection roller 3 and a longitudinal axis 11 of the flatness measuring device 1, which runs transversely to the deflection rollers 3, 5 and 7, depending on a deviation of the actual position of the hot strip 2 from a predetermined target position of the hot strip 2 to vary. To explain this, the inlet-side deflection roller 3 is shown in two pivoting positions, once in solid lines and once in dashed lines, with the horizontal pivotability of the inlet-side deflection roller 3 being indicated by a double arrow 12. For this purpose, the inlet-side deflection roller 3 is arranged to be displaceable about an axis of rotation (not shown) perpendicular to a band section of the hot strip 2 fed to the inlet-side deflection roller 3 and perpendicular to the plane of the drawing, the axis of rotation being relative the longitudinal axis 10 of the inlet-side deflection roller 3 is arranged offset from the center of the inlet-side deflection roller 3. The adjusting device 9 has an electromechanical drive (not shown) connected to the inlet-side deflection roller 3 or a hydraulic actuating cylinder connected to the inlet-side deflection roller 3.

The adjusting device 9 is set up to determine an actual position of the inlet-side deflection roller 3, to determine a target position of the inlet-side deflection roller 3 from the deviation of the actual position of the hot strip 2 from the predetermined target position of the hot strip 2, and a target adjustment speed value for adjusting the angle α between the longitudinal central axis 10 the inlet-side deflection roller 3 and the longitudinal axis 11 of the flatness measuring device 1 depending on a deviation of the actual position of the inlet-side deflection roller 3 from the target position of the inlet-side deflection roller 3. In addition, the adjusting device 9 is set up to determine a speed of a sideways movement of the hot strip 2 and to determine the target adjustment speed value depending on the speed of the sideways movement of the hot strip 2.

The adjusting device 9 is further set up to pivot the middle deflection roller 7 in a plane which is arranged perpendicular to the longitudinal axis 11 of the flatness measuring device 1 and perpendicular to the plane of the drawing. In addition, the adjusting device 9 is set up to pivot the middle deflection roller 7 in the plane depending on an angle value by which the angle α between the longitudinal center axis 10 of the inlet-side deflection roller 3 and the longitudinal axis 11 of the flatness measuring device 1 can be varied by means of the adjusting device 9.

The flatness measuring device 1 can have a holding frame, not shown, on which the inlet-side deflection roller 3, the outlet-side deflection roller 5 and / or the middle deflection roller 7 are or are rotatably mounted, the Adjusting device 9 is connected via the holding frame to the respective deflection rollers 3, 5 and 7 or the deflection rollers 3, 5 and 7 and the holding frame can be moved together with the deflection rollers 3, 5 and 7 connected to it.

Figure 1B shows a schematic side view of the in Figure 1A shown flatness measuring device 1. The vertical pivotability of the middle deflection roller 7 is shown, once in solid lines and once in dashed lines, the vertical pivotability of the middle deflection roller 7 being indicated by a double arrow 13.

Figure 2 shows a flowchart of an exemplary embodiment of a method according to the invention for operating a flatness measuring device for measuring the flatness of a hot strip within a hot rolling mill. The flatness measuring device can be in accordance with the Figures 1A and 1B shown embodiment.

First, an actual position list of the hot strip is recorded. From the actual position List and a predetermined target position L _target of the hot strip, a difference is formed by means of a subtractor D1 of the adjusting device, which is fed to a center controller M of the adjusting device of the flatness measuring device. Depending on the difference, the center controller M generates a target position P _target of the deflection roller connected to the adjusting device, which optimizes the strip travel of the hot strip. In addition, an actual position P _Ist of the deflection roller connected to the adjusting device is recorded. From the actual position P Act _of the deflection roller and the target position P _Soll of the deflection roller, a further difference is formed by means of a further subtractor D2 of the adjusting device, which is fed to a swivel controller S of the adjusting device of the flatness measuring device. Depending on the difference D2, the swivel controller S generates an adjustment speed value for adjusting the angle between the longitudinal center axis of the deflection roller connected to the adjustment device and the longitudinal axis of the flatness measuring device. The means of the subtractor D1 generated difference is also fed to a differential controller D of the adjusting device, which determines a speed of a sideways movement of the hot strip and uses this speed to determine an additional value for the adjusting speed. The adjustment speed value generated by the swivel controller S and the additional value generated by the differential controller D are added using an adder A of the adjusting device, resulting in a target adjustment speed value V _Soll , which can be used to control actuators of the adjusting device.

Consequently, according to the method, an angle between a longitudinal central axis of the deflection roller connected to the adjusting device and a longitudinal axis of the flatness measuring device running transversely to the deflection rollers is varied depending on a deviation of the actual position List of the hot strip from a predetermined target position L _Soll of the hot strip. According to the method, an actual position P _Is of the deflection roller connected to the adjusting device, the position of which can be varied accordingly, is determined, from the deviation of the actual position List of the hot strip from the specified target position L _Soil of the hot strip, a target position P _Soll of the deflection roller connected to the adjusting device determined and a target adjustment speed additional value for adjusting the angle between the longitudinal center axis of the deflection roller connected to the adjusting device and the longitudinal axis of the flatness measuring device as a function of a deviation of the actual position P _Is of this deflection roller from the target position P _Soil of this deflection roller is determined. In addition, according to the method, a speed of a sideways movement of the hot strip is determined and the additional target adjustment speed value is determined depending on the speed of the sideways movement of the hot strip.

In order to compensate for a change in the geometry of the clamping of the hot strip in the flatness measuring device, which is caused by adjusting the deflection roller connected to the adjusting device, the deflection roller, the position of which can be varied accordingly, or another deflection roller of the flatness measuring device can be pivoted in a plane which is arranged perpendicular to the longitudinal axis of the flatness measuring device. The pivoting of this deflection roller in the plane can be carried out depending on an angle value by which the angle between the longitudinal center axis of the deflection roller, the pivoting of which caused the change in geometry, and the longitudinal axis of the flatness measuring device can be varied.

Reference symbol list

1

Flatness measuring device

2

Hot strip

3

inlet side deflection roller

4

leadership role

5

deflection roller on the outlet side

6

Belt running direction

7

middle pulley

8th

Detection device

9

Adjustment device

10

Longitudinal center axis of 3

11

Longitudinal axis of 1

12

Double arrow (swivel from 3)

13

Double arrow (swivel from 7)

A

adder

D

Differential regulator

D1

subtractor

D2

subtractor

LIst

Actual position of 2

LSoll

Target position of 2

M

Mid control

Pist

Actual position of 3, 5, 7

PSoll

Target position of 3, 5, 7

S

Swivel controller

Vtarget

Target adjustment speed value

α

Angle between 10 and 11

Claims (15)

1. Planarity measuring device (1) for measuring a planarity of a hot strip (2) within a hot-rolling mill, comprising at least one deflecting roller (3) at the inlet side for contacting a first large side of the hot strip (2), at least one deflecting roller (5) at the outlet side for contacting the first large side of the hot strip (2) and at least one middle deflecting roller (7) which with respect to a strip running direction (6) of the hot strip (2) is arranged between the inlet-side deflecting roller (3) and the outlet-side deflecting roller (5) and is adjustable against a second large side of the hot strip (2) opposite the first large side of the hot strip (2) and which serves as a planarity measuring roller, characterised by at least one detecting device (8) for detecting an actual position (L_Ist) of the hot strip (2) and at least one adjusting device (9) which is connected with the detecting device (8) and at least one of the deflecting rollers (3, 5, 7) and which is arranged to vary an angle (α) between a longitudinal centre axis (10) of the respective deflecting roller (3, 5, 7) connected with the adjusting device (9) and a longitudinal axis (11), which extends transversely to the deflecting rollers (3, 5, 7), of the planarity measuring device (1) in dependence on a deviation of the actual position (L_Ist) of the hot strip (2) from a predetermined target position (L_Soll) of the hot strip (2).
2. Planarity measuring device (1) according to claim 1, characterised in that the adjusting device (9) is arranged to determine an actual position (P_Ist) of the respective deflecting roller (3, 5, 7) connected with the adjusting device (9), to determine a target position (P_Soll) of this deflecting roller (3, 5, 7) from the deviation of the actual position (L_Ist) from the predetermined target position (L_Soll) of the hot strip (2) and to determine a target adjusting speed value (V_Soll) for adjusting the angle (α) between the longitudinal centre axis (10) of this deflecting roller (3, 5, 7) and the longitudinal axis (11) of the planarity measuring device (1) in dependence on a difference of the actual position (P_Ist) of this deflecting roller (3, 5, 7) from the target position (P_Soll) of this deflecting roller (3, 5, 7).
3. Planarity measuring device (1) according to claim 2, characterised in that the adjusting device (9) is arranged to determine a speed of a lateral movement of the hot strip (2) and to determine the target adjusting speed value (V_Soll) in dependence on the speed of the lateral movement of the hot strip (2).
4. Planarity measuring device (1) according to any one of claims 1 to 3, characterised in that the adjusting device (9) is arranged to pivot the respective deflecting roller (3, 5, 7) connected with the adjusting device (9) and/or at least one other deflecting roller (3, 5, 7) in a plane arranged perpendicularly to the longitudinal axis (11) of the planarity measuring device (1) and to perform the pivotation of the respective deflecting roller (3, 5, 7) in the plane in dependence on an angle value by which the angle (α) is variable by means of the adjusting device (9) between the longitudinal centre axis (10) of the respective deflecting roller (3, 5, 7) and the longitudinal axis (11) of the planarity measuring device (1).
5. Planarity measuring device (1) according to any one of claims 1 to 4, characterised in that the respective deflecting roller (3, 5, 7) connected with the adjusting device (9) is arranged to be displaceable about an axis of rotation extending perpendicularly to a strip section of the hot strip (2) feedable to this deflecting roller (3, 5, 7), wherein the axis of rotation is arranged through a centre of this deflecting roller (3, 5, 7) or is offset with respect to the longitudinal axis (10) of this deflecting roller (3, 5, 7) from the centre of this deflecting roller (3, 5, 7).
6. Planarity measuring device (1) according to any one of claims 1 to 5, characterised in that the adjusting device (9) comprises at least one electromechanical drive connected with the respective deflecting roller (3, 5, 7) connected with the adjusting device (9) or at least one hydraulic setting cylinder connected with this deflecting roller (3, 5, 7).
7. Planarity measuring device (1) according to any one of claims 1 to 6, characterised by at least one mounting frame on which the inlet-side deflecting roller (3), the outlet-side deflecting roller (5) and/or the middle deflecting roller (7) is or are rotatably mounted, wherein the adjusting device (9) is connected by way of the mounting frame with the respective deflecting roller (3, 5, 7) and the mounting frame is displaceable in common with the respective deflecting roller (3, 5, 7) connected therewith.
8. Planarity measuring device (1) according to any one of claims 1 to 7, characterised in that at least one deflecting roller (3, 5, 7) has a circumferential surface with an increased roughness.
9. Planarity measuring device (1) according to any one of claims 1 to 8, characterised in that at least deflecting roller (3, 5, 7) has a wear-inhibiting circumferential coating.
10. Planarity measuring device (1) according to any one of claims 1 to 9, characterised in that the detecting device (8) is so arranged and equipped as to detect an inlet-side actual position (L_Ist) of the hot strip (2) or an outlet-side actual position (L_Ist) of the hot strip (2).
11. Hot-rolling mill with at least one planarity measuring device (1), characterised in that the planarity measuring device (1) is constructed in accordance with any one of claims 1 to 10.
12. Method of operating a planarity device (1) for measuring a planarity of a hot strip (2) within a hot-rolling mill, wherein the planarity measuring device (1) comprises at least one deflecting roller (3) at the inlet side for contacting a first large side of the hot strip (2), at least one deflecting roller (5) at the outlet side for contacting the first large side of the hot strip (2) and at least one middle deflecting roller (7) which with respect to a strip running direction (6) of the hot strip (2) is arranged between the inlet-side deflecting roller (3) and the outlet-side deflecting roller (5) and is adjustable against a second large side of the hot strip (2) opposite the first large side of the hot strip (2) and which serves as a planarity measuring roller, characterised in that an actual position (L_Ist) of the hot strip (2) is detected and an angle (α) between a longitudinal centre axis (10) of at least one deflecting roller (3, 5, 7) and a longitudinal axis (11), which extends transversely to the deflecting rollers (3, 5, 7), of the planarity measuring device (1) is varied in dependence on a deviation of the actual position (L_Ist) of the hot strip (2) from a predetermined target position (L_Soll) of the hot strip (2).
13. Method according to claim 12, characterised in that an actual position (P_Ist) of the deflecting roller (3, 5, 7), the position of which is correspondingly variable, is determined, a target position (P_Soll) of this deflecting roller (3, 5, 7) is determined from the deviation of the actual position (L_Ist) of the hot strip (2) from the predetermined target position (L_Soll) of the hot strip (2) and a target adjusting speed value (V_Soll) for adjusting the angle (α) between the longitudinal centre axis (10) of this deflecting roller (3, 5, 7) and the longitudinal axis (11) of the planarity measuring device (1) is determined in dependence on a deviation of the actual position (P_Ist) of this deflecting roller (3, 5, 7) from the target position (P_Soll) of this deflecting roller (3, 5, 7).
14. Method according to claim 13, characterised in that a speed of a lateral movement of the hot strip (2) is determined and the target adjusting speed value (V_Soll) is determined in dependence on the speed of the lateral movement of the hot strip (2).
15. Method according to any one of claims 12 to 14, characterised in that the deflecting roller (3, 5, 7), the position of which is correspondingly variable, and/or at least one other deflecting roller (3, 5, 7) is or are pivoted in a plane arranged perpendicularly to the longitudinal axis (11) of the planarity measuring device (1) and the pivotation of the respective deflecting roller (3, 5, 7) in the plane is carried out in dependence on an angle value by which the angle (α) between the longitudinal centre axis (10) of the respective deflecting roller (3, 5, 7) and the longitudinal axis (11) of the planarity measuring device (1) is variable.

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