Method for operating a rolling stand

Abstract

The invention relates to a method for the operation of a rolling stand 150 for rolling a metal strip, which has at least one side guide strip arranged on at least one of both sides - seen in the transport direction of the metal strip - at the inlet and / or outlet of the rolling stand for guiding the metal strip. In order to be able to calculate the force or position setpoints for the control of the side guide strip better than in the prior art, taking into account the avoidance of bowing in the metal strip at the outlet of the rolling stand, the force or position setpoints for the control of the side guide strip are calculated as a function of the actual wedge already calculated for the pivot position control and / or as a function of the calculated actual position deviation.

Description

[Technical field]

[0001] The invention relates to a method for the operation of a rolling stand for rolling a metal strip, which at the inlet and / or outlet has a side guide strip arranged on at least one of both sides - seen in the transport direction of the metal strip - for guiding the metal strip. [Background technology]

[0002] Methods of this type for the operation of a rolling stand are basically known from the prior art.

[0003] US Pat. No. 5,399,433 discloses a method for thickness control on the basis of position measurements in the bending cylinder of a rolling stand.

[0004] DE 10 200 03 133 A1 describes a method for controlling the roll gap of a rolling stand, in which it is recommended that each bending cylinder in the rolling stand is assigned a position or displacement detector. The measurements provided by the position or displacement detectors allow for more precise adjustment of the roll gap, thereby achieving optimal infeed or outfeed of the metal strip and optimal rolling of the rolled metal strip with the flatness and required profile to be achieved. In addition, this patent describes the relationship between the tilt position of the roll gap and the lateral movement of the metal strip to be rolled out of the roll gap of the rolling stand.

[0005] DE 10 2004 03 133 A1 discloses a method and an apparatus for the purposeful adjustment of the rough strip geometry in a rolling stand, in particular claiming a method for the hot rolling of a strip, in which for the movement control of the strip a swivel control with dynamic adjustment of the roughing stand and a position and force control of side guides connected upstream and downstream of the roughing stand are proposed. The control of the adjustment of the swivel and the control of the adjustment of the side guides are connected to one another in such a way that one or more passes are adapted to deform a curved or wedge-shaped slab into a straight, non-wedge-shaped rough strip in a reversible motion or continuous operating state. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] European Patent No. 698428 B [Patent Document 2] International Publication No. 2003 / 053604 [Patent Document 3] International Publication No. 2006 / 119984 Summary of the Invention [Problem to be solved by the invention]

[0007] The object of the present invention is to provide a method for the operation of a rolling stand with a tilt position control and, coupled with said tilt position control, a position control and a force control for the control of the side guide strips, comprising: To improve the determination of force or position setpoints for the adjustment and control of the side guide strips, taking into account the avoidance of bowing in the metal strip at the exit of the rolling stand. [Means for solving the problem]

[0008] This problem is solved by the method claimed in claim 1. This method is optionally calculating an actual misalignment of the metal strip after the rolling relative to a centerline of the rolling stand; the actual wedge and / or the actual misalignment is inspected based on tolerances; and that the coupling is performed only if the actual wedging and / or the actual misalignment is not allowed, and that this coupling is performed by the following steps: - on at least one of the two sides at the inlet and / or outlet of the rolling stand - in the transport direction of the metal strip, individual control of the side guide strips by individually predefined force or position setpoints as a function of the calculated actual wedge strength and / or as a function of the calculated actual positional deviation, in order to prevent bowing of the metal strip leaving the rolling stand; Steps: It is characterized by:

[0009] In essence, the solution to this problem consists in calculating the force or position setpoints for the control of the side guide strip as a function of the actual wedge strength already calculated for the swivel position control and / or as a function of the calculated actual position deviation. Effect of the Invention

[0010] The claimed basic control circuit in the form of a swivel control is utilized for the detection and elimination of wedge shapes in the metal strip to be rolled. Any wedge shapes occurring in the incoming metal strip are compensated for by the pivoting reference value, i.e. the adjusting cylinders of the rolling stands are thus given deviating values ​​for their adjustment position or their adjustment force in order to compensate for deviating thickness values ​​of the metal strip in the width direction of the metal strip. Overall, the claimed method allows resource-efficient production in hot rolling lines for flat products. Increased productivity and material yield are possible due to reduced downtime. The properties and quality of the metal strip to be rolled are optimized and the plant operator is relieved of the burden in controlling the strip running.

[0011] In accordance with the present invention, the claimed linking step comprises: and / or only if the calculated actual wedge quality is greater than a given maximum permissible wedge quality. This is only carried out if the calculated actual misalignment of the metal strip after rolling is not permitted, since this calculated actual misalignment is greater than a predefined maximum permitted eccentricity. Only if at least one of the above-mentioned limits is exceeded is the likewise claimed position control or force control of the side guides activated in addition to the claimed swivel control. In other words, in addition to the correction of the adjustment value of the adjusting cylinder within the scope of the swivel control, the side guide strips are also adjusted by correction values ​​taking into account a predefined target position or a predefined target force as a function of the current adjustment value of the respective side guide strip. These side guide strips should be - viewed in the transport direction of the metal strip - individually controllable on each side.

[0012] According to a first embodiment, the slewing control aims at a control difference between the calculated actual wedge quality of the metal strip and a predetermined target wedge quality as close to zero as possible, i.e. the thickness of the metal strip to be rolled should be the same as far as possible on the drive and operating sides of the rolling stand, i.e. on the left and right edges, unless certain deviations are allowed.

[0013] According to a further embodiment of the invention, the calculation of the actual wedge and / or the actual misalignment is performed indirectly, in that these actual values ​​are derived from at least one of the following directly measurable quantities, for example the difference in the rolling forces, i.e. the difference between the driving and operating side rolling forces at the adjusting cylinder of the rolling stand, as determined via pressure measurements: Furthermore, the actual position of the adjustment cylinder and thus the position measurement of the bending cylinder in the rolling stand close to the roll gap can be directly compared as measured quantities. In particular, position measurement of the bending cylinder close to the roll gap allows for extremely precise information output regarding the derivation of the actual wedge strength.

[0014] Alternatively, a direct measurement of wedgeiness can be made. In general, at least one of the four measurements mentioned above needs to be made in order for an information output for the actual wedgeiness to be derivable from these measurements. Since the above-mentioned measurement values ​​also provide an information output regarding the central or eccentric position of the metal strip in the rolling line, additionally or alternatively, an information output regarding the central position or the actual misalignment of the metal strip can also be derived.

[0015] in a calculation device for calculating the target positions or the target forces for the side guide strips, In a simple implementation, the pairs of values ​​can be stored tabularly, so that, for example, a wedge value of x mm is assigned a movement of the strip by y mm (target position); or In an alternative configuration, it is possible for an xy adjustment curve to be stored, this xy adjustment curve being based on a formula taking into account deformation resistance, stand strength, etc.; or In a further alternative configuration, it is possible for a complete deformation model to be stored, which takes into account the material flow and the complete deformation of the metal strip in the rolling stand for the inlet conditions to be adjusted.

[0016] The invention primarily provides that the side guide strips are simply controlled via the actuators by predefined setpoints (without feedback control circuits), but alternatively the control can also take place in the form of a position control circuit or a force control circuit.

[0017] The method according to the invention can be used for finishing stands as well as for roughing stands.

[0018] This specification is accompanied by a drawing, which illustrates diagrammatically the method according to the invention. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a schematic diagram of a method according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] In the upper half, the figure illustrates a diagram of the swivel control 100 and in the lower half, in schematic form, the control 300 of the side guide strip 350 in this figure.

[0021] The swivel control 100 and the control 300 of the side guide strips are linked via a block 170 for the derivation or calculation of the actual wedge of the metal strip and / or the actual misalignment of this metal strip from the direct measured measurements and from the tolerance check 200.

[0022] The swivel control 100 is represented by a conventional control circuit, which comprises a calculation unit 110 for the calculation of a predefined target wedge or target swivel value of the work rolls for adjusting the roll gap in the rolling stand 150. Within the scope of the turning control, the calculated target wedge is compared with the actual wedge calculated in block 170. The difference between the target wedge and the actual wedge is calculated in comparator 120 and output as the so-called control difference e to the subsequent controller 130. From the control difference e as input quantity, the controller 130 calculates a position adjustment signal for the adjustment element 140, which in the case of swivel control is formed by the adjustment cylinders of the work rolls in the roll stand, which are adjusted within the range of control to the corresponding roll gap in the roll stand 150 in response to the above-mentioned position adjustment signal. The above-described pivot control 100 is characterized by a feedback in which, in further method steps, the position of the adjustment cylinder (method step 160-2) and / or the position of the bending cylinder of the rolling stand (method step 160-1) and / or the differential force of the adjustment cylinder (method step 160-3) are directly measured in order to derive by calculation therefrom, i.e. indirectly detect, the actual wedging and / or the actual misalignment in the above-described block 170. Alternatively, the actual wedge can be determined from a direct measurement on the metal strip (method step 160-4). The same is true for the measurement of the eccentricity of the metal strip (method step 160-5).

[0023] In a subsequent query step 200, the calculated actual misalignment and / or the calculated actual wedgeiness are checked whether they are acceptable, i.e. whether they are below a respective pre-given maximum limit value. If both values ​​are permissible to that extent, then according to the invention no special control of the side guide strip 350 is carried out; rather, this side guide strip remains in a fixedly set guide position for central guidance of the strip within the roll gap. If the acceptability check is positive, this means that no impermissible large curvatures are recognized or predicted in the metal strip running out of the rolling stand 150 and therefore no correction of the strip run of the metal strip by the side guide strips is necessary.

[0024] The situation is different if one of the two actual values, i.e. the calculated actual wedge of the outgoing metal strip or the calculated actual positional deviation, exceeds a respectively predefined maximum permissible limit value. In that case, a correction of the strip run of the metal strip by the side guide strip is necessary. The control of the side guide strip 350 can be by position or by force. For this purpose, in the position calculation unit 310 a position target value is calculated, to which the side guide strip 350 is adjusted by means of an adjustment element 340, for example a hydraulic cylinder.

[0025] Alternatively, a force setpoint for the side guide strip 350 can be calculated using the force calculation unit 310', said strip 350 then being adjusted or regulated to the force setpoint by means of the adjustment element 340. Essentially, the adjustment or control of the side guide strip 350 takes place without feedback, i.e. within the scope of the simple control just described.

[0026] Alternatively, the adjustment of the side guide strips 350 may also be in the form of position control or force control. In the position control, the calculated target position of the respective side guide strip is calculated based on the actual position of this side guide strip 350, which was previously determined by measurement technology in step 360 of the method, and the control difference e from this actual position to the position. p This position control difference is applied as an input variable to the position controller 330, which calculates a position adjustment signal for the adjustment element 340 from this position control difference. The adjustment element 340 then controls the side guide strip 350 in response to the calculated position adjustment signal. Analogously, in the force control, the target force calculated in the calculation step 310' is calculated by the actual force previously detected by measurement technology in the measurement step 360' and the control difference e of this actual force in a comparison device 320'. kThis force control difference is applied as an input quantity to a force controller 330', which calculates from this position control difference a force adjustment signal for the adjustment element 340. The adjustment element 340 then controls the side guide strip 350 in response to the force adjustment signal described above.

[0027] Measurements in the strip running direction within or after the rolling stand can likewise affect the adjustment of the strip before the rolling stand, thereby improving the wedge and / or centering of the subsequent strip longitudinal sections. Since measurements in the strip running direction within or after the rolling stand can likewise affect the adjustment of the strip after the rolling stand, the wedge and / or centering of the currently measured strip longitudinal portions is improved. [Explanation of symbols]

[0028] 100 Turning Control 110 Calculation unit for target value for wedge or swivel value of work roll 120 Wedge Comparator 130 Turning Controller 140 Adjustment elements, in particular adjustment cylinders 150 Rolling Stand 160-1 Measuring the position of bending cylinder 160-2 Measuring the position of the adjustment cylinder 160-3 Measurement of differential force of adjustment cylinder 160-4 Measurement of actual wedge strength of metal strips 160-5 Eccentricity / Misalignment Measurement 170 Calculation device for actual wedge and / or actual misalignment 200 Check for acceptability 300 Side guide strip control 310 Calculation device for target position 310´ Calculation device for target forces for side guide strips 320 Comparator 320´ Comparator 330 Position Controller 330´ Force Controller 340 Adjusting elements for controlling the side guide strips, in particular hydraulic cylinders 350 Side guide strip 360 Determining the measured value of the actual position of the side guide strip 360´ Measurement value detection for the actual force of the side guide strips In addition, the present application relates to the invention described in the claims, but may also include the following as other aspects. 1. A method for operating a rolling stand (150) for rolling metal strip, comprising: The rolling stand at least one side guide strip arranged on at least one of the two sides of the rolling stand for guiding the metal strip at the inlet and / or outlet side - viewed in the transport direction of the metal strip -, The method comprises the steps of: performing a slewing control (100) in which the actual wedge quality of the metal strip is calculated and controlled to a predetermined target wedge quality by dynamic adjustment of the work rolls in the rolling stand; and performing a position or force control (300) of at least one of said side guide strips (350); The method includes the steps of: The pivot control and the position or force control (300) of the side guide strips (350) may be coupled to each other; In the method, optionally, calculating an actual misalignment of the metal strip after said rolling relative to a centerline of the rolling stand (150); the actual wedginess and / or the actual misalignment is inspected for acceptability; and that the coupling is performed only if the actual wedging and / or the actual misalignment is not allowed, and that this coupling is performed by the following steps: At least one of the two sides of the entry and / or exit of the rolling stand (150) - as viewed in the transport direction of the metal strip - individual control of the side guide strips (350) by individually predefined force or position nominals as a function of the calculated actual wedge strength and / or as a function of the calculated actual position deviation, in order to prevent bowing of the metal strip leaving the rolling stand, The method comprises the steps of: A method comprising: 2. The step of inspection comprises the following substeps: checking whether the calculated actual wedge value is less than a predefined maximum allowable wedge value, and therefore the calculated actual wedge value is allowable; and / or - checking whether the calculated actual misalignment of the metal strip after rolling is smaller than a predetermined maximum permissible eccentricity, and therefore the calculated actual misalignment of the metal strip after rolling is permissible; having the sub-steps 2. The method according to claim 1, 3. In controlling the actual wedge quality of the metal strip to the predetermined target wedge quality, a control difference (e) between the target wedge quality and the actual wedge quality is calculated; and Through the force and / or the position of the adjusting cylinder (140) as an adjusting element of the work roll, the profile for the roll gap is adjusted in accordance with the calculated control difference (e): so that the control difference after the rolling of the metal strip is as close to zero as possible. Individually, pre-fed and adjusted; 3. The method according to claim 1 or 2, characterized in that 4. Calculating the actual wedge and / or actual misalignment (170) At least one of the following detectable amounts: the actual position of the bending cylinder of said rolling stand (160-1); and / or the actual position of the adjustment cylinder (160-2); and / or the differential force of said adjusting cylinder (160-3); indirectly by derivation from measuring the actual wedgeability of the strip (160-4); and / or Measuring the eccentricity / misalignment of said metal strip (160-5); Directly by 4. The method according to any one of claims 1 to 3, characterized in that 5. The individual control of the side guide strips (350) is in the form of force control on at least one of the two sides at the entry and / or exit of the rolling stand (150), The following partial steps: Measurement of the actual force (360´) for each side guide strip (350); The control difference of the force (e k ) calculation; and The control difference of the force (e k control of an adjustment element (340) for adjusting the force of the respective side guide strip (350) according to the force of the respective side guide strip (350) in such a way that the control difference of the force is as close as possible to zero; 5. The method according to any one of claims 1 to 4, comprising the steps of: 6. The individual control of the side guide strips (350) is in the form of position control at least on one of the two sides at the entry and / or exit of the rolling stand (150), The following partial steps: measuring the actual force (360) of each side guide strip (350); The control difference of the position (e p ) calculation; and The control difference (e p control of an adjustment element (340) for adjusting the position of the respective side guide strip (350) in response to said position control difference being as close as possible to zero; 5. The method according to any one of claims 1 to 4, comprising the steps of: 7. The method according to any one of claims 1 to 6, characterized in that the rolling stand (150) is a roughing stand or a finishing stand.

Claims

1. 1. A method for operating a rolling stand (150) for rolling a metal strip, comprising the steps of: The rolling stand at least one side guide strip arranged on at least one of the two sides of the rolling stand for guiding the metal strip, as viewed in the transport direction of the metal strip, at the inlet and / or outlet of the rolling stand, The method comprises the steps of: - implementing a slewing control (100) in which the actual wedge quality of the metal strip is calculated and controlled to a predefined target wedge quality by dynamic adjustment of the work rolls in the rolling stand; and performing a position or force control (300) of at least one of said side guide strips (350); The method includes the steps of: The pivot control and the position or force control (300) of the side guide strips (350) may be coupled to each other; In the method, Optionally, calculating an actual misalignment of the metal strip after the rolling relative to a centerline of the rolling stand (150); the actual wedginess and / or the actual misalignment is inspected for acceptability; and that the coupling is performed only if the actual wedging and / or the actual misalignment is not allowed, and that this coupling comprises the following steps: At least one of the two sides - seen in the transport direction of the metal strip - at the entry and / or exit of the rolling stand (150), - individual control of the side guide strips (350) by individually predefined force or position setpoints depending on the calculated actual wedge strength and / or depending on the calculated actual position deviation, in order to prevent bowing of the metal strip leaving the rolling stand, The method comprises the steps of: A method comprising:

2. The step of inspection comprises the following substeps: a check whether the calculated actual wedge characteristic is smaller than a predetermined maximum allowable wedge characteristic, and therefore the calculated actual wedge characteristic is allowable; and / or - checking whether the calculated actual misalignment of the metal strip after rolling is smaller than a predetermined maximum permissible eccentricity, and therefore the calculated actual misalignment of the metal strip after rolling is permissible; having the sub-steps 2. The method of claim 1 .

3. In controlling the actual wedge quality of the metal strip to the predetermined target wedge quality, a control difference (e) between the target wedge quality and the actual wedge quality is calculated; and Through the force and / or position of the adjusting cylinder (140) as an adjusting element of the work roll, the profile for the roll gap is adjusted according to the calculated control difference (e): so that the control difference after the rolling of the metal strip is as close to zero as possible. Individually, pre-fed and adjusted; 3. The method according to claim 1 or 2, characterized in that

4. The calculation of the actual wedginess and / or actual misalignment (170) may include: At least one of the following detected amounts: the actual position of the bending cylinder of said rolling stand (160-1); and / or the actual position of the adjustment cylinder (160-2); and / or The differential force of the adjusting cylinder (160-3), indirectly by derivation from Measuring the actual wedgeability of the strip (160-4); and / or Measuring the eccentricity / misalignment of the metal strip (160-5); Directly by 4. The method according to claim 1, wherein the first and second electrodes are arranged in a first direction.

5. The control of each of the side guide strips (350) is in the form of force control on at least one of the two sides at the entry and / or exit of the rolling stand (150), The following partial steps: Measurement of the actual force (360') for each side guide strip (350); The control difference of the force (e ｋ ) calculation; and The control difference of the force (e ｋ 4. Control of an adjustment element (340) for the adjustment of the force of the respective side guide strip (350) in response to said force, such that the control difference of said forces is as close as possible to zero; 5. The method according to claim 1, further comprising the steps of:

6. The control of each of the side guide strips (350) is in the form of position control at least on one of the two sides at the entry and / or exit of the rolling stand (150), The following partial steps: Measuring (360) the actual position of each side guide strip (350); The control difference of the position (e ｐ ) calculation; and The position control difference (e ｐ 4. Control of an adjustment element (340) for adjusting the position of the respective side guide strip (350) in response to said adjustment element (340) so that the control difference of said position is as close as possible to zero.

5. The method according to claim 1, further comprising the steps of:

7. 7. The method according to any one of claims 1 to 6, wherein the rolling stand (150) is a roughing stand or a finishing stand.

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