EP2259882A1

EP2259882A1 - Operating method for a multi-stand rolling mill train comprising a strip thickness detection means that utilizes the continuity equation

Info

Publication number: EP2259882A1
Application number: EP09714928A
Authority: EP
Inventors: Hans-Joachim Felkl
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2008-02-27
Filing date: 2009-02-10
Publication date: 2010-12-15
Anticipated expiration: 2029-02-10
Also published as: US20100326155A1; RU2010139416A; WO2009106422A1; BRPI0908531A2; CN101959623B; EP2259882B1; PL2259882T3; CN101959623A; RU2507016C2; DE102008011275A1; US8186195B2

Abstract

A strip (6) is fed to one of (2 - 5) the rolling stands (1 - 5) (rolling stand in question) of a multi-stand rolling mill with a known inlet thickness (d1 - d4) and exits the rolling stand in question (2 - 5) with a strip thickness (d2 - d5). Measurement parameters (vR, vW) are determined that are characteristic of the inlet-side velocity (v1 - v4) of the strip (6) and the outlet side velocity (v2 - v5) of the strip (6) with respect to the rolling stand in question (2 – 5). By means of the measurement parameters (vR, vW), the inlet-side velocity (v1 - v4) of the strip (6) and the outlet side velocity (v2 - v5) of the strip (6) are determined with respect to the rolling stand in question (2 – 5). By means of the inlet thickness (d1 - d4), the inlet-side velocity (v1 - v4) of the strip (6) and the outlet side velocity (v2 - v5) of the strip (6), the strip thickness (d2 - d5) is determined with respect to the rolling stand in question (2 – 5). Taking into account the determined strip thickness (d2 - d5), further measures are taken. The measurement parameter (vW) for the inlet-side velocity (v1 - v4) of the strip (6) is the roller peripheral velocity (vW) of the rolling stand (1 – 4) directly prior to the rolling stand in question (2 – 5). Alternatively or in addition, the measurement parameter (vW) for the outlet-side velocity (v2 – v5) of the strip (6) is the roller peripheral velocity (vW) rolling stand in question (2 – 5). The peripheral precession of the strip (6) in the respective rolling stand (2 – 5) is modeled. The respective velocity (v1 - v5) of the strip (6) is determined using the respective roller peripheral velocity (vR) and the peripheral precession of the strip (6) in the respective rolling stand (1 - 5).

Description

description

Operating procedure for a multi-stand rolling mill with strip thickness determination using the continuity equation

The present invention relates to an operating method for a multi-stand rolling mill,

a strip being fed to one of the rolling stands (considered roll stand) of the rolling train with a known input thickness and leaving the rolling stand under consideration with a strip thickness,

in which measurement variables are detected which are characteristic with respect to the considered roll stand for the inlet side speed of the belt and the outlet side speed of the belt,

wherein the inlet side speed of the belt and the outlet side speed of the belt are determined on the basis of the detected measured variables with respect to the rolling mill considered, with respect to the rolling stand considered on the basis of FIG

Input thickness, the inlet side speed of the belt and the outlet side speed of the belt, the belt thickness is determined

- taking further measures taking into account the determined strip thickness.

The present invention further relates to a computer program comprising machine code which is directly executable by a controller for a multi-stand rolling mill, the execution of the machine code by the controller causing the controller to operate the mill according to such an operating method. The present invention also relates to a data carrier with such a computer program stored on the data carrier in machine-readable form.

Furthermore, the present invention relates to a control device for a multi-stand rolling train, wherein the control is configured such that it operates the rolling mill according to an operating method of the type described above.

Finally, the present invention relates to a rolling mill,

wherein the rolling train has a plurality of rolling stands, which have passed through a belt in succession,

wherein the rolling train may have a front thickness measuring device immediately preceding one of the rolling stands of the WaIz road (considered roll stand), or the rolling stand considered may be the first rolling mill stand of the rolling train,

- wherein the rolling train has a control device of the type described above,

- Wherein the control device, the rolling stands and, if present, the thickness measuring device are connected to each other in terms of data technology.

The objects described above are well known. By way of example, reference is made to JP 04-158 912 A and JP 06-210 338 A.

From DE 33 03 829 Al an operating method for a multi-stand rolling train is known in which, inter alia, the lead of a strip in a nip of a rolling mill is determined. To determine the lead, among other things, the inlet side and the outlet side strip thickness are needed.

In multi-stand cold rolling mills, the strip thickness - ie the thickness at which the strip in each case runs out of one of the rolling stands - is generally measured only behind the first and behind the last rolling stand. Behind the other rolling mills of the rolling mill (intermediate stands), no such measurement of the strip thickness takes place. It can therefore happen that occur by rolling in the intermediate stands Banddickenfehler that are noticed only behind the last rolling stand. On Reason for the note of the band thickness error is in the prior art, although a control command for the last or the penultimate rolling stand of the rolling mill determined and output to the corresponding mill. By doing so, however, occurring tape thickness errors are correctable only with a relatively large dead time. This is especially true when the control command for the penultimate rolling stand of the rolling mill is determined. Furthermore, only a late correction of an occurring band thickness error occurs. Also, the correction of a band thickness error is not always possible in full.

It would be advantageous if, for each roll stand, the strip thickness was known with which the strip runs out of the respective roll stand. Because then resulting band thickness errors could be corrected immediately or other measures are taken.

It is conceivable to arrange a thickness measuring device behind each roll stand for this purpose. However, thickness measuring devices are expensive and are therefore not used in practice.

Furthermore, it is conceivable to detect the rolling force for each intermediate stand, with which the strip is rolled in the intermediate stand, and to determine how far that is based on the set rolling gap of this intermediate stand and the respective rolling force in conjunction with the spring constant of the respective intermediate stand considered intermediate framework, and so the effective rolling gap and thus the band thickness to mittein. However, this procedure is too inaccurate. It is therefore not used in practice.

The object of the present invention is to provide possibilities by means of which the strip thickness of a strip running out of a considered rolling stand can be determined in a simple, reliable and accurate manner without requiring a thickness measuring device arranged downstream of the relevant rolling stand. The object is procedurally achieved by an operating method with the features of claim 1. Advantageous embodiments of the operating method are the subject of the dependent claims 2 to 10.

According to the invention, an operating method of the initially mentioned type is configured by

the measured quantity for the inlet-side speed of the belt is the roller peripheral speed of the rolling stand immediately preceding the considered rolling stand and / or the measured value for the outlet-side speed of the belt is the roller circumferential speed of the considered rolling stand,

- that the lead of the band is modeled in the respective rolling stand and

- That the respective speed of the belt is determined on the basis of the respective roller peripheral speed and the lead of the band in the respective rolling stand.

The required in the prior art thickness measuring device is thus realized indirectly and mathematically. It is used as it were a "soft sensor".

In a preferred embodiment of the present invention, the band consists of successive sections, each section being assigned a respective section thickness at each point in time. The sections are tracked as they pass through the mill train. The section thickness of each section corresponds to the input thickness before entering the considered roll stand and to the strip thickness after leaving the considered roll stand. This procedure allows for improved dynamics in compensating for belt thickness errors.

It is possible that the input thickness is measured by means of a front thickness gauge upstream of the considered roll stand. In particular, in multi-stand rolling mills of the prior art often a front Ckenmesseinrichtung arranged between the first and the second roll stand of the rolling train. This embodiment can also be maintained within the scope of the present invention. In principle, the arrangement of the front thickness gauge, if required, is freely selectable. It could, for example, also be arranged in front of the first roll stand of the rolling train.

As an alternative to measuring the input thickness by means of a thickness measuring device, it is possible that a rolling stand is arranged directly upstream of the rolling stand under consideration and that the strip thickness is determined by means of an operating method described above for the rolling mill immediately preceding the rolling stand under consideration.

The further measures may include, for example, an indication of the determined strip thickness. Alternatively or additionally, a positioning command for the rolling stand under consideration and / or at least one rolling stand that is different from the rolling stand under consideration can be determined.

As also already mentioned, in multi-stand rolling mills of the prior art, a rear thickness measuring device is often arranged downstream of the last rolling stand of the rolling train. This embodiment can also be maintained within the scope of the present invention. For each roll stand of the rolling mill, which is followed by a rear thickness gauge, it is possible

- That by means of the rear thickness gauge an outlet thickness of the tape is detected and

- That the other measures include a comparison of the determined for the considered rolling mill strip thickness with the measured outlet thickness.

For example, it is possible that, with regard to at least one of the rolling stands considered, the inlet-side speed of the belt and / or the outlet-side speed of the belt can be determined using the measured variables recorded. determination of a preliminary investigation. In this case, for example, the determination method can be adapted based on the comparison.

Alternatively or additionally, it is possible that in the case of excessive deviation of the determined strip thickness of the measured outlet thickness an error message is issued. It is thus possible to carry out plausibility checks.

Programmatically, the object is achieved by a computer program, the computer program comprising machine code which is directly executable by a control device for a multi-stand rolling mill, the execution of the machine code by the control device causing the control device to design the rolling mill according to an operating method of the above-explained Art operates. Furthermore, the object is achieved programmatically by a data carrier on which such a computer program is stored in machine-readable form.

In terms of equipment, the object is achieved by a control device for a multi-stand rolling train, wherein the control device is designed such that it operates the rolling train according to an operating method of the type described above. In this case, the control device can in particular be designed as a programmable control device which, during operation, executes a computer program of the type described above.

In terms of plant technology, the task is finally solved by a rolling mill,

- wherein the rolling train for at least one of the rolling stands (rolling stand considered) of the rolling mill detection means by means of which the measured variables can be detected, with respect to the considered roll stand for the incoming lateral speed of the tape and the outgoing speed of the tape are characteristic,

wherein at least one of the measured variables is the roll circumferential speed of the considered roll stand or the roll peripheral speed of the rolling mill immediately preceding the rolling stand considered,

- Wherein the rolling train either a directly to the considered rolling mill upstream front thickness gauge, by means of which for the considered rolling mill, the input thickness is measurable, or has a detection means by which for the considered rolling mill, the input thickness supplied by the detecting means, on a rolling stand under consideration Sizes directly related to the rolling stand, the input thickness can be determined, or the considered roll stand is the first roll stand of the rolling train,

- wherein the rolling train has a control device of the type described above,

- Wherein the control device, the rolling stands, the detection devices and, if present, the thickness measuring device and the detection device are connected to each other in terms of data technology.

Further advantages and details emerge from the following description of exemplary embodiments in conjunction with the drawings. In a schematic representation:

1 shows schematically the structure of a multi-stand

Rolling mill, FIGS. 2 to 5 are flowcharts,

6 shows a section of a multi-stand rolling train and

7 shows a running over a roll band.

According to FIG. 1, a multi-stand rolling train has several rolling stands 1 to 5. The rolling stands 1 to 5 are run through by a band 6 in succession. Shown here are in FIG 1 five rolling stands 1 to 5. The rolling mill could, however alternatively more or less rolling mills 1 to 5, for example 3, 4, 6, 7, ... rolling mills. Furthermore, the rolling train of FIG. 1 is designed as a cold rolling mill (tandem mill). This embodiment is the standard case. Exceptionally, however, the present invention could also be applied to a hot strip mill.

According to FIG 1, a Abhaspei 7 and a front S-roller set 8 are arranged in front of the first rolling stand 1. Behind the last roll stand 5 are a rear S-roller set 9 and a

Aufhaspel 10 arranged. The presence of the reel 7, 10 and the S-roller sets 8, 9 is common, but not mandatory.

Finally, a front thickness measuring device 11 is arranged between the first and the second roll stand 1, 2 of the rolling train. Furthermore, the last roll stand 5 is followed by a rear thickness gauge 12 downstream. The presence of the thickness measuring devices 11, 12 is common, but not mandatory in the context of the present invention.

The rolling stands 1 to 5, the reel 7, 10, the S-roller sets 8, 9 and the thickness measuring devices 11, 12 are connected to a control device 13 for the multi-stand rolling train data technology. The control device 13 is designed to operate the rolling mill in accordance with an operating method which will be explained in detail below in conjunction with FIGS. 2 to 7.

The control device 13 is generally designed as a programmable control device 13, which executes a computer program 14 during operation. The computer program 14 in this case comprises machine code 15, which is directly executable by the control device 13. The execution of the machine code 15 in this case causes the control device 13 to operate the rolling mill in accordance with an operating method according to the invention. The computer program 14 may have already been deposited in the control device 13 during the production of the control device 13. Alternatively, it is possible to supply the computer program 14 to the control device 13 via a computer-computer connection. The computer-computer connection is not shown in FIG 1 here. It can be designed, for example, as a connection to a LAN or to the Internet. Again alternatively, it is possible to store the computer program 14 on a data carrier 16 in machine-readable form and to feed the computer program 14 to the control device 13 via the data carrier 16. The design of the data carrier 16 is arbitrary nature. For example, it is possible that the data carrier 16 is designed as a USB memory stick or as a memory card. Shown in FIG. 1 is an embodiment of the data carrier 16 as a CD-ROM.

The first rolling stand 1 is operated in the presently preferred embodiment of the present invention not in the manner according to the invention, but in a conventional way se. The operation of the first rolling mill 1 will be explained in more detail below in conjunction with FIG.

According to FIG. 2, the control device 13 controls the rolling train in a step S 1 such that the belt 6 is fed to the first rolling stand 1 with an input thickness d 0. The input thickness dθ can be known in this case, for example, because the first rolling stand 1, a further thickness measuring device is arranged upstream or because the thickness of the wound on the reel 7 belt 6 are known in advance. However, it is not absolutely necessary for the input thickness dθ of the strip 6 entering the first roll stand 1 to be known.

In a step S2, measured variables are detected that are characteristic of the first rolling stand 1 for the outgoing speed vi of the belt 6. Furthermore, in a step S3, the strip thickness d1 is detected by means of the front thickness measuring device 11, that is to say the thickness d1 at which the strip 6 leaves the first rolling stand 1. As indicated schematically in FIG. 1, the band 6 consists of successive sections 17. Each section 17 is assigned a respective section thickness d at each point in time. The sections 17 are tracked as they pass through Waiz Street. A tracking is hereby professional lighting generally known. The control device 13 therefore assigns the strip thickness d1 as a new section thickness d in a step S4 to each section 17 for which the strip thickness d1 was respectively detected by means of the front thickness measuring device 11.

In a step S5, the control device 13 determines a setting command for the first roll stand 1. The setting command is determined in this case taking into account the detected strip thickness dl. The determined positioning command is output to the first rolling mill 1 immediately after the determination.

The step S5 is only optional and therefore only shown in dashed lines in FIG. Because it is possible that, alternatively or in addition to step S5, a step S6 is present. However, since step S6 is also optional, step S6 in FIG. 2 is also shown in dashed lines only.

In step S6, the control device 13 determines a setting command for the second rolling stand 2 (or one of the following rolling stands 3 to 5), also taking into account the strip thickness d1 detected on the outlet side of the first rolling stand 1. However, the outputting of the control command to the second rolling stand 2 (or the corresponding downstream rolling stand 3 to 5) is preferably not immediately after the determination of the control command, but only when the corresponding section 17 of the belt 6 in the second rolling stand 2 (or the corresponding subsequent roll stand 3 to 5) is rolled. The corresponding time can be determined on the basis of the tracking of the sections 17 without further ado.

In contrast to the first rolling stand 1, the second, the third and the fourth stand 2, 3, 4 operated in a novel, inventive manner. This procedure se is explained in more detail below with reference to FIG 3 for the second rolling stand 2. For the third and the fourth rolling stand 3, 4 analogous versions apply.

According to FIG. 3, the control device 13 controls the rolling train such that the belt 6 is fed to the second rolling stand 2 and runs out of the second rolling stand 2. In contrast to the procedure for the first roll stand 1, in this case the input thickness d 1 with which the strip 6 enters the considered roll stand 2 is known. For the second

Roll stand 2, this is immediately and immediately apparent, since the input thickness dl corresponds to the thickness dl, which was detected by the front thickness gauge 11.

In a step S12, measured quantities which are characteristic of the second rolling stand 2 for the inlet-side speed vi of the belt 6 and the outlet-side speed v2 of the belt 6 are detected. Possible measured variables will be explained later in conjunction with FIG. 6.

In a step S13, the control device 13 determines the inlet-side speed vi of the belt 6 and the outgoing-side speed v2 of the belt 6 based on the measured variables (namely the actual measured variables) with respect to the second rolling stand 2 in step S12.

In a step S14 determines the controller 13 with respect to the second roll stand 2 based on the input thickness dl, the inlet side speed vi of the belt 6 and the outlet side speed v2 of the belt 6, the belt thickness d2, ie the belt thickness d2, with the belt 6 from the second Roll stand 2 expires. The determination is based on the continuity equation, ie on the relationship

dl = - -dl v2 The determination of the outlet-side strip thickness d2 is of course carried out for the currently rolled section 17 of the strip 6.

Furthermore, in a step S15, the strip thickness d2 determined in step S14 is assigned to the corresponding section 17 as its new section thickness d. By virtue of this procedure, the section thickness d of each section 17 corresponds to the input thickness d 1 before entering the second rolling stand 2 and to the strip thickness d 2 after it leaves the second rolling stand 2.

Then, taking into account the determined strip thickness d2 further measures are taken. As a rule, the further measures include at least one of the steps

S16, S17 and S18. Since each individual (although not all together) of the steps S16, S17 and S18 is optional, the steps S16, S17 and S18 are shown in dashed lines in FIG.

In step S16, the controller 13 determines a

Control command for the second rolling stand 2. The determination of the control command takes place here taking into account the determined in step S14 tape thickness d2. The determined positioning command is issued to the second WaIz- scaffold 2 immediately after the determination.

In step S17, the control device 3 determines a setting command for the third rolling mill 3 (or a subsequent roll stand 4, 5). The determination of the control command for the third roll stand 3 (or the corresponding following

Rolling stand 4, 5) takes place here also taking into account the strip thickness d2, with which the belt 6 expires from the second rolling stand 2. However, the positioning command for the third rolling stand 3 (or the corresponding following rolling stand 4, 5) is preferably not immediately output to the third rolling stand 3 (or the corresponding following rolling stand 4, 5), but only when the corresponding rolling stand 4, 5 17 into the third rolling stand 3 (or the corresponding rolling stand 4, 5) enters.

The steps S16 and S17 correspond in content to the steps S5 and S6 of FIG. 2. Therefore, the corresponding explanations apply to the steps S5 and S6, so that both steps S16, S17 can be present.

In step S18, the determined strip thickness d2 is displayed to the operator 18, for example via a viewing device.

As already mentioned, analogous designs apply to the third and the fourth roll stand 3, 4. The only significant difference is that in the second rolling mill 2, the input thickness dl is a measured size, while the third and the fourth rolling stand 3, 4, the respective input thickness d2, d3 on the basis of the above-explained in connection with FIG 2 approach, applied to the immediately upstream rolling mill 2 or 3, is determined.

Also for the last roll stand 5 of the rolling train, its input thickness d4 is determined according to the method explained above in connection with FIG. Furthermore, the last rolling stand 5 is operated in a manner according to the invention. However, it differs from the above explained in conjunction with FIG 3 procedure. The procedure for the last roll stand 5 will be explained in more detail below in conjunction with FIG. However, since the procedure of FIG 4 over long distances with the procedures of FIG 2 and 3 matches, as far as possible, reference is made to the explanations there.

According to FIG. 4, the control device 13 executes steps S21 to S25. The steps S21 to S25 correspond with the exception of the fact that they are related to the last roll stand 5, with the steps Sil to S15 of FIG. 3, so that reference is made to the statements there. Furthermore, the controller 13 executes steps S26 and S27. The steps S26 and S27, with the exception of the fact that they are related to the last roll stand 5 and the detected thickness d5 'for distinguishing from the strip thickness d5 is referred to as outlet thickness d5', with the

Steps S3 and S4 of FIG 2, so that reference may be made to the statements there.

Furthermore, the control device 13 executes a step S28. In step S28, the control device 13 determines a setting command for the last roll stand 5 and / or for the penultimate rolling stand 4. The setting command is issued immediately after the determination to the corresponding roll stand 5 and 4 respectively. The step S28 is similar in approach to the step S5 of FIG 2 and the step S16 of FIG 3, so that reference may be made to the statements there. However, the determination of the setting command can be made taking into account the strip thickness d5 determined in step S24 or taking into account the final thickness d5 'of the strip 6 detected in step S26 (or a combination of the two thicknesses d5, d5'). In this case, a determination is to be considered taking into account the detected final thickness d5 '.

Finally, the controller 13 executes a step S29. In step S29, the controller 13 takes further action. The control device 13 preferably takes the further measures based on a comparison of the strip thickness d5 determined for the last roll stand 5 of the rolling train with the measured final thickness d5 '.

The further measures of step S29 may include, for example, a step S31 according to FIG. 5. In step S31, the controller 13 adapts the determination method used to determine the intake-side speed vi to v4 of the belt 6 and / or the discharge-side speed v2 to v5 of the belt 6 in steps S13 and S23. As an alternative or in addition to step S31, steps S32 to S34 may be present according to FIG. In step S32, the controller 13 determines the value of a logical variable OK. The logical variable OK assumes the value TRUE then and only if the determined strip thickness d5 does not deviate too much from the measured outlet thickness d5 '. Otherwise, the logical variable OK assumes the value FALSE.

In step S33, the controller 13 checks the value of the logical variable OK. Depending on the result of the check, the control device 13 executes step S34 in which it outputs an error message to an operator 18 of the rolling train.

The steps S32 to S34 thus correspond to a plausibility check, so that it is possible to detect a defect. In this case, the defect may have occurred, for example, in one of the thickness measuring devices 11, 12 or in one of the measuring devices which detect the measured variables which are characteristic of the inlet-side speed vi to v4 or the outlet-side speed v2 to v5 of the belt 6.

In connection with FIG. 6, various procedures for determining the velocities v.sub.0 to v.sub.5 of the belt 6 are explained below. The procedures can be used alternatively. In particular, it is sufficient to access one of the procedures described below in conjunction with FIG. 6 for each speed vθ to v5 to be determined. Furthermore, it is common and the rule that all velocities vθ to v5 are determined in the same way. However, this is not necessary. Rather, it is possible to take a particularly suitable procedure for each individual speed vθ to v5. In particular, it is therefore possible for (at least) one of the rolling mills 1 to 5, the inlet-side speed vθ to v4 of the belt 6 in a different way and Way to determine as the outlet side speed vi to v5 of the belt 6th

The possible procedures are explained below in conjunction düng with FIG 6 on the basis of a section of the rolling mill, which is bounded by two the section limiting rolling stands 1 to 5, here the rolling stands 3 and 4. However, the embodiments of FIG 6 are readily transferable to the other rolling mills 1, 2 and 5 of the rolling mill.

By way of example, it is possible to provide a measuring device 19 in the form of a laser. In this case, it is such that the respective speed vθ to v5 of the belt 6 is detected by a laser measuring method. Furthermore, in this case, the detected measured variable corresponds directly to the respective velocity vθ to v5 of the strip 6.

Alternatively, it is possible to provide as a measuring device a roller 20 whose peripheral speed vR is detected. The roller 20 is made in this case to the belt 6 and runs with the belt 6 with. Typical examples of suitable rollers 20 are the rollers of one of the S roller sets 8, 9, rollers of a ski lifter, tension measuring rollers or rollers of a plan measuring device.

Also in the embodiment of the measuring device as a roller 20, the respective measured variable vR usually corresponds directly to the respective speed vθ to v5 of the belt 6.

Again, alternatively, it is possible that the measuring device, based on the location for which the respective speed vi to v5 should apply, are designed as rollers 21 of the upstream rolling stand 3 and that the measured variable with the circumferential speed vW of the respective rollers 21 corresponds. In this case, the peripheral speed vW of the rollers 21 is fed to a model 22 in which the lead of the belt 6 in the respective rolling stand 3 is modeled. The fashion Dell 22 is usually implemented within the control device 13 here. In this case, the model 22 determines the respective speed vθ to v5 of the belt 6 on the basis of the respective roller peripheral speed vW and the advance of the belt 6 in the respective rolling stand 1 to 5.

In particular, in the case of the latter approach, the measured variable vW is linked to the respective velocity vi to v5 of the strip 6 by means of a scaling factor. However, the linkage by means of a corresponding scaling factor can also be useful, although to a lesser extent, for measured variables vR that are detected by means of a laser 19 or a roller 20. For example, this will be explained in more detail below in connection with FIG. 7 for the roller 20.

According to FIG. 7, the band 6 wraps around the roller 20 over a wrap angle α. The belt 6 moves at the belt speed v. The roller 20 has the roller peripheral speed vR. The belt speed v and the roller peripheral speed vR are about the relationship

v = vR \ l + k - D

k, k is a factor that depends on the wrap angle α. For small wrap angles α, the factor k tends to approach zero, and for increasing wrap angles α it increases. At most, the factor k can assume the value one, d is the local strip thickness, D the diameter of the roll 20.

Of course, the detected measured variables vR, vW must be supplied to the control device 13. Irrespective of the detected measured variable vR, vW, therefore, the corresponding measuring device 19 to 21 must be connected to the control device 13 in a correspondingly data-related manner. It has been explained above that the operating method according to the invention (see FIG. 3) is applied to the rolling stands 2, 3 and 4. For the last roll stand 5, a modified operating method according to the invention was used (cf. FIG. 4), for the first rolling stand 1 a conventional operating method. In principle, however, it is also possible to operate the first and / or the last roll stand 1, 5 according to the same operating mode which was explained above in connection with FIG. 3 for the second, the third and the fourth stand 2, 3, 4. For example, it is possible to pre-allocate the front thickness measuring device 11 to the first rolling stand 1 and also to detect or determine the inlet-side speed vθ of the strip 6 for the first rolling stand 1. As a measured variable for the inlet-side speed vθ for the first rolling stand 1, in particular the peripheral speed vR of the rollers of the front S-roller set 8 comes into question. In an analogous manner, it is possible to omit the rear thickness gauge 12. In this case, the strip thickness d5 of the strip 6 emerging from the last roll stand 5 is determined directly in accordance with the procedure of FIG. 3. It only eliminates the detection of the final thickness d5 '(steps S26 and S27) and the taking of the other measures (step S29).

The present invention has many advantages. In particular, due to the operating method according to the invention, in which

on the one hand, from the ratio of the on and off-side velocities vi to v5 of the band 6, the current one

Stichabnahme of each considered rolling mill 2 to 5 is determined and

on the other hand, the determined strip thickness d 2 to d 5 are assigned to the respective rolled section 17 and the respective section 17 is tracked through the rolling train,

a significantly improved control of the rolling stands 1 to 5 and thus achieved a superior operating result become. In particular, the dimensional accuracy of the finished strip 6 can be significantly improved. This applies in particular to the area of slow travel (for example when threading in and out of the belt 6 or during the changeover between two belts 6 in continuous operation). As a by-product, it is also possible to check the pliability of strip thickness measurements by comparing determined strip thicknesses d1 to d5 and measured strip or final thicknesses d1, d5 '.

The above description is only for explanation of the present invention. The scope of the present invention, however, is intended to be determined solely by the appended claims.

Claims

claims

1. Operating method for a multi-stand rolling mill,

a strip (6) being fed to one (2-5) of the rolling stands (1-5) (rolling stand) of the mill train of a known input thickness (dl-d4) and of the rolling mill (2-5) under consideration with a strip thickness (d2 - d5) expires,

- In which measured variables (vR, vW) are detected, with respect to the considered roll stand (2-5) for the inlet side speed (vi - v4) of the belt (6) and the outgoing speed (v2 - v5) of the belt (6 ) are characteristic,

- Based on the detected measured variables (vR, vW) with respect to the considered rolling stand (2 - 5) determines the inlet side speed (vi - v4) of the belt (6) and the outgoing side speed (v2 - v5) of the belt (6) become,

wherein, with respect to the rolling stand (2 - 5) considered, the strip thickness is determined by the input thickness (dl - d4), the inlet side speed (vi - v4) of the strip (6) and the outlet side speed (v2 - v5) of the strip (6) d2

- d5) is determined,

- taking into account the determined strip thickness (d2 - d5) further measures are taken, characterized

- that the measured variable (vW) for the inlet side speed (vi - v4) of the belt (6) is the roller peripheral speed (vW) of the rolling mill (1 - 4) immediately preceding the rolling mill (2 - 5) under consideration and / or

Measured variable (vW) for the outlet-side speed (v2-v5) of the belt (6) is the roller peripheral speed (vW) of the rolling mill considered (2 - 5),

- That the lead of the band (6) in each rolling stand (2 - 5) is modeled and

- That the respective speed (vi - v5) of the belt (6) on the basis of the respective roller peripheral speed (vR) and the lead of the strip (6) in the respective rolling mill (1 - 5) is determined.

2. Operating method according to claim 1, characterized in that the band (6) consists of successive sections (17), that each section (17) at each time a respective section thickness (d) is assigned, that the sections (17) Traversed through the rolling mill are tracked and that the section thickness (d) of each section (17) before entering the considered

Roll stand (2 - 5) with the input thickness (dl - d4) and after the exit from the considered roll stand (1 - 5) with the strip thickness (d2 - d5) corresponds.

3. Operating method according to claim 1 or 2, characterized in that the input thickness (dl) by means of a rolling mill (2) upstream front thickness gauge (11) is measured.

4. Operating method according to claim 3, characterized in that the front thickness measuring device (11) between the first and the second roll stand (1, 2) of the rolling train is arranged.

5. Operating method according to claim 1 or 2, characterized in that the rolling mill considered (3 - 5) a rolling stand (2-4) is directly upstream and that for the rolling mill (3 - 5) immediately upstream rolling stand (2-4 ) the strip thickness (d2 - d4) by means of an operating method according to one of claims 1 to 8 is determined.

6. Operating method according to one of the above claims, characterized in that the further measures comprise an indication of the determined strip thickness (d2 - d5).

7. Operating method according to one of the above claims, characterized in that the further measures the Er- with a setting command for the considered rolling mill (2

- 5) and / or at least one of the rolling mill (2 - 5) different rolling stand (3-5) of the rolling mill.

8. Operating method according to one of claims 1 to 6, characterized

in that a discharge thickness (d5 ') of the strip (6) is detected by means of a rear thickness measuring device (12) arranged downstream of the considered rolling stand (5), and

- That the further measures comprise a comparison of the determined for the considered roll stand (5) strip thickness (d5) with the measured outlet thickness (d5 ').

9. Operating method according to claim 8, characterized in that with respect to at least one of the considered rolling stands (2-5) the inlet side speed (vi - v4) of the belt (6) and / or the outlet side speed (v2 - v5) of the belt (6 ) are determined on the basis of the detected measured variables (vR, vW) using a determination method and that the determination method is adapted on the basis of the comparison.

10. Operating method according to claim 8 or 9, characterized in that in case of excessive deviation of the determined strip thickness (d5) of the measured outlet thickness (d5 ') an error message is output.

A computer program, the computer program comprising machine code (15) which is directly executable by a control device (13) for a multi-stand rolling train, the execution of the machine code (15) by the control device (13) causing the control device (13) the rolling mill operates according to an operating method according to any one of the preceding claims.

12. Data carrier with a stored on the disk in machine-readable form computer program (14) according to claim 11.

13. Control device for a multi-stand rolling train, wherein the control device is configured such that it operates the rolling mill according to an operating method according to one of claims 1 to 10.

14. Control device according to claim 13, characterized in that it is designed as a programmable control device which executes a computer program (14) according to claim 11 during operation.

15. rolling mill,

- wherein the rolling mill has a plurality of rolling mills (1 - 5), which have passed successively through a belt (6),

- wherein the rolling train for at least one (2-5) of the rolling stands (1-5) (rolling stand considered) of the rolling mill detection means (19 - 21), by means of which the measured variables (vR, vW) are detectable with respect to the considered rolling stand ( 2-5) are characteristic of the inlet side speed (vi-v4) of the belt (6) and the outgoing speed (v2-v5) of the belt (6),

wherein at least one of the measured quantities (vR, vW) is the roller peripheral speed (vW) of the considered rolling stand (2-5) or the rolling stand (1-4) immediately preceding the rolling stand (2-5) under consideration, - the rolling train is either a the upstream of the considered rolling stand (2) directly upstream Dickenmessein- direction (11), by means of which for the considered rolling mill (2) the input thickness (dl) is measurable, or a detecting device (13) by means of which for the considered rolling mill (3 5) the input thickness (d2-d4) is determined on the basis of variables fed to the rolling mill (2 - 4 or the rolling mill under consideration (1) is the first rolling stand (1) of the rolling train, wherein the rolling train has a control device (13) according to claim 13 or 14, wherein the control device (13), the rolling stands (1 - 5), the detection devices (19 - 21) and, if present, the thickness measuring device (11) and the detection device (13) are connected to each other in terms of data technology.