EP1230992A2 - Method for operating a rolling-mill train and control system for a rolling-mill train - Google Patents

Abstract

Method for operating a rolling train for producing profiles which contains several roller systems (4, 6, 8) comprises measuring the bar thickness, flange height and flange thickness produced by each roller system. These are compared with desired values and the rollers adjusted as required. An Independent claim is included for a control system for the roller train.

Description

The invention relates to a method for operating a rolling mill for profiled rolling stock, in which the rolling stock is divided by a number in one rolling direction successive, each comprising a number of work rolls Roll stands is performed, each roll stand with regard to its operating parameters is set to a number of setpoints. It continues to affect a control system for such a rolling mill.

A number of rolling stands can be used in a rolling mill to roll a rolling stock are used. The roll stands are for the passage of a usually elongated rolling stock and provided in one also seen as the direction of rolling of the rolling stock arranged in series or in succession. A rolling mill with one A plurality of such roll stands can be used in particular when machining one profiled rolling stock are used. The profiled rolling stock can in particular have a so-called "heavy profile" and for example as U-profile or be designed as a so-called double-T beam.

When processing such profiled rolling stock usually come so-called universal frameworks are used at least in part. Such as when Universal mill stands usually comprise two pairs cooperating horizontal rollers, which together have a web thickness of Form the resulting double T-beam determining the nip. Related to the The rolling direction seen to the side of it are inside the universal stand between arranged these horizontal rolls two opposite vertical rolls, that limit the rolling stock in the lateral direction. Form the vertical rollers one roll gap each, which rolls horizontally together with the bale length is decisive for the overall width of the resulting double-T beam.

When operating a rolling mill with such rolling stands, especially with Universal stands, each roll stand is usually used for a number of its Operating parameters are loaded with setpoints that are selected such that the finished rolled product comes as close as possible to a target profile. Setpoints can be specified directly for the manipulated values with which the actuating elements of the roll stand are acted upon, for example a control value for a hydraulic pressure for setting a desired rolling force or a control value for a desired positioning of a roller. In modern However, rolling mills can also have setpoints for derived, comparatively complex ones Operating parameters such as the roll gap are specified as such, such a setpoint in a subordinate regulation in suitable control values for the actual operating parameters are implemented.

In any case, the finished rolled product can be used with regard to the target profile for a highly precise production of the rolling stock comparatively narrow boundary conditions or are subject to tolerance limits. Compliance is comparatively difficult narrow tolerance limits, among other things, during external influences which may change during the rolling process, for example the environmental conditions or the properties of the incoming rolling stock. It is therefore customary to comply with comparatively narrow tolerance limit values continuous monitoring of the rolling process and occasional intervention of the operating team in an assigned regulation. However, only a limited accuracy can be achieved. Just through that Compliance with comparatively narrow tolerance limits is the production of such profiled rolling stock is also particularly complex.

The invention is therefore based on the object of a method for operating a Rolling mill of the type mentioned above, which is comparatively low Manufacturing effort compliance with particularly narrow tolerance limits enabled in the production of a profiled rolling stock. Furthermore, one for the Implementation of the method suitable control system for such Rolling mill can be specified.

With regard to the method, this object is achieved according to the invention by the Profile of the rolling stock emerging from the rolling mill is determined and with a Target profile is compared, the or each target value of the or each roll stand with reference to a framework-specific weighting factor the deviations of the determined profile from the target profile with a correction target value is applied.

The invention is based on the consideration that especially for compliance narrow tolerance limits for the profile of the rolling stock this profile continuously should be monitored, with an evaluation made as soon as possible, especially taken into account directly in the ongoing rolling process should be. This can result in deviations in the profile actually produced of the specified target profile is still taken into account during the production of the rolling stock and compensated by specifying suitable correction values for the target values become. The correction values can be specified as additional setpoints and be taken into account in the regulation as soon as suitable measured values for the actual profile. The activation of the additional setpoints can be synchronized in length, by specifying an additional setpoint for a comparable one Roll length position, or synchronous, i.e. by specifying an additional setpoint for different roll stands at the same time.

Particularly high accuracy can be achieved when tracking the setpoints, by compensating for errors as directly as possible where they arise. The invention takes into account in particular the finding that exceeding tolerances Deviations in the manufactured profile of the rolling stock from different Sources come from each of the rolling stands running through and can be accumulated in the product running out of the rolling mill. Such accumulated contributions to the deviation from the target profile should be particularly important simple means and especially using only one only measuring system suitable for determining the actual profile of the rolling stock produced can be compensated. This is a breakdown of the total existing deviation from the target profile required corrective measures to the individual roll stands, taking into account empirical values from previous rolling processes or including system-specific ones Expertise in the individual roll stands provided. such Experience and / or special knowledge are in the framework-specific Weighting factors laid down, based on which the total to be made Correction in the profile of the rolling stock suitable for a correction of the target values of the individual roll stands is divided. The weighting factors can especially in the form of a "learning function" or as a self-optimizing one Function designed and continuous, at regular intervals or if necessary with regard to new experiences from previous rolling processes be supplemented.

Compliance with particularly narrow tolerance limits is made possible if between successive rolling stands constant tension-compression ratios in the Rolling stock is available. To support this, data is advantageously exchanged of the scaffold adjustment with a correction setpoint Train-pressure control.

The output of correction values for the target values can in particular be comparative promptly, in the manner of an "online update". In particular can still be in one while processing the rolling stock Roll stand, the already rolled area ("rolling stock head") already for one Evaluation is available, a tracking of the setpoints for the still unfinished part. The correction setpoints provided for this expediently take into account the relative parameter changes that occur between the processing of the rolling stock head and its central part.

The method is particularly suitable for operating a rolling mill for production of double-T beams. Such a rolling mill comprises at least some so-called universal scaffolds, each of which is a couple of horizontal as well as a couple of vertical rolls. In such a rolling mill preferably the target values for the operating parameters of the web thickness, the Flange height and / or the flange thickness of the rolling stock by applying suitable correction setpoints for compliance with particularly narrow tolerance limit values optimized. The profile of a double-T beam can be created namely describe essentially by a central web at the end each flanges extending transversely thereto are formed. Because of the web thickness, the flange height and the flange thickness of the double T-beam is therefore this essentially completely described. The adjustment of the web thickness can in particular by setting a corresponding roll gap between the horizontal rollers of the universal scaffold. The universal scaffold can be controlled in such a way that a setpoint is specified for a web thickness is that this setpoint, however, within one of the universal framework assigned actuator in suitable derived operating parameters, such as Position values for the individual horizontal rollers implemented becomes.

In an advantageous development, the respective framework-specific weighting factor Specified depending on the rolling stock. This takes into account the additional knowledge borne that the contribution of a single roll stand to the total deviation the profile actually produced from the target profile of the rolling stock is not exclusively from the position of the respective mill stand in the rolling mill, but rather can also depend on the type of rolling stock to be produced. The correction setpoint applied to the respective setpoint for a roll stand , and in particular the scaffold-specific basis on which it is based Weighting factor is thus with regard to the type of rolling stock to be produced specified.

The horizontal rollers of a roll stand interacting in pairs can be employed together. This results in an even, symmetrical Loading of the rollers interacting in pairs with a manipulated variable, for example a set pressure. This automatically results in a central one Alignment with a reference plane. Deviating from this, however in one or more of the roll stands, the two interacting in pairs Horizontal rollers must be employed separately. The rollers are therefore independent of one another positionable so that the absolute location of what they have formed Change the roll gap with respect to a reference plane, for example the roll plane leaves. The additional flexibility that can be achieved through the provision a new degree of freedom for compliance with particularly narrow tolerance limits To be able to use, is in a particularly advantageous embodiment the roll stands, the rolls of which are independent of each other on the basis of roll-specific Setpoints are operable, the or each setpoint of a roller Reference to a roll-specific weighting factor based on the deviations of the determined profile from the target profile with a correction setpoint. The concept is based on the roll-specific weighting factors compensation of rolling errors close to the source not only between the Roll stands, but also within a single stand between them maintain independently adjustable rollers.

To overcompensate for rolling errors in the sense that other to reliably avoid tolerance limits independent of the respective setpoint, the or each correction setpoint is expediently set to a parameter-specific one Maximum value limited. In an alternative or additional advantageous Continuing education becomes a correction setpoint for horizontal adjustment of a roll stand and a correction setpoint for a vertical adjustment of a Roll stand specified, the ratio of these correction setpoints to one specifiable maximum value is limited.

The experience from previous rolling operations is particularly favorable To make usable, the or each correction setpoint and in particular the stand-specific weighting factor is advantageously based on the rolling result given previous rolling processes. For example a large number of previous rolling results were evaluated with regard to this what characteristic values of the roll stands relative to each other have been too special favorable or particularly unfavorable rolling results with regard to have the profile of the rolling stock. A proposal for a roll gap correction to the operating personnel or advantageously also automatically especially if the sum of the correction setpoints is a predefinable one Limit exceeds. With such a specification, this can in particular also Result of an immediately preceding and therefore particularly current one Rolling process with a comparatively high weight flow into the evaluation. Such consideration of previous rolling results can in particular advantageous embodiment in the form of pre-settings or "pre-setting values" take place for those for a newly arriving rolling stock, for the still no evaluable actual values are available, a correction of Standard setpoints based on experience with previous machining operations he follows. It is advantageously particularly based on measured values a particularly reliably rolled length range ("fillet piece") of an earlier rolled rolled stock.

Especially in the production of a double-T beam, a so-called Reverse rolling processes are used. This goes through Rolled stock in the rolling mill a number of successive rolling stands in the kind of a pendulum motion several times. After the first run through the respective roll stands, the rolling stock is stopped and vice versa Direction again through the respective mill stands. This can be for a predeterminable Number of passes, also referred to as stitches, are repeated, until the rolling stock for further processing or a final rolling step is finally fed to another part of the rolling mill. Especially with Such a multiple pass of the rolling stock can be an interim Determination of the present profile with regard to a target profile to be achieved and a derived tracking of the setpoints for the multiple runs Roll stands particularly helpful with regard to maintaining tight Tolerance limits. In a particularly advantageous development, Repeated passage of the rolling stock through the rolling mill the respective correction setpoint taking into account the rolling result of one Run specified. The correction setpoint thus takes the form of an adaptation from a first contribution, for a previous rolling stock and doing so is the same stitch or pass, and from a second amount, the for the rolling stock and a previous pass or Stitch is characteristic, together.

Such an adaptation is therefore related to the roll pass and can also be related to the rolling stock be designed. The adaptation enables a special one quick reaction or compensation in the event of rolling errors. For investigation the wall profile of the rolling stock present after each pass can be seen in the rolling direction on both sides of the multiple passes A measuring device for determining the contour of the rolling stock is arranged in the rolling stands his. For a particularly simple construction, however, only one is Measuring device provided, which is expedient in the original rolling direction seen after the last of the rolling stands to be run several times is arranged. With such a configuration, the adaptation after "Stitch x", d. H. the evaluation of the actually existing profile after the umpteenth Pass through the respective roll stands, for the "stitch x + 2", d. H. the x + 2nd pass through the roll stands. In order to do this also in the run The opposite direction, i.e. the x + 1st stitch or pass, is particularly error-free To be able to carry out, advantageously takes place on the basis of the present measured values for the xth pass, an interpolation of the expected values for the upcoming Pass x + 1 in the opposite direction.

Regarding the control system for a rolling mill for profiled rolling stock, at which the rolling stock by a number of successive in a rolling direction, each have a number of roll stands comprising work rolls is, the specified task is solved with a control unit that a Control element assigned to the rolling stand has a setpoint for an operating parameter specifies, and the input side with a measuring device for determining a profile characteristic of the rolling stock and connected to a storage module is, wherein the control unit with reference to the target value of the respective roll stand to a framework-specific weighting factor stored in the memory module on the basis of the deviations of the determined profile characteristic value from a target profile characteristic value with a correction setpoint.

The advantages achieved with the invention are in particular that the consideration of framework-specific weighting factors in the determination of correction setpoints for the setpoints of the roll stands is particularly close to the cause Error compensation when operating the rolling mill is enabled.

The product rolled out of the rolling mill is accumulated in the Form of a total deviation of existing rolling defects taking into account from plant-specific expertise to individual contributions from individuals Roll stands or individual rolls returned. The weighting factors or their respective amounts can in particular by rolling technology Expertise is determined and also limited. It is also comparative a particularly precise compensation of the error contributions with little effort enables so that particularly narrow tolerance limits in the manufacture of the profiled rolling stock can be maintained. This also makes the necessary Interventions by the operating personnel are kept particularly low, and moreover also a comparatively frequent sampling on the rolling stock is not necessary is. As a result, the downtimes of the rolling mill are also due to Tolerance violations are kept low, so that the rolling mill as a whole can have particularly high throughput.

Fig. 1

einen Teil einer mehrgerüstigen Walzstraße mit zugeordnetem Steuerungssystem,

Fig. 2

schematisch ein Universalgerüst, und

Fig. 3

ein Profil eines Doppel-T-Trägers.

An embodiment of the invention is explained in more detail with reference to a drawing. In it show:

Fig. 1

part of a multi-stand rolling mill with assigned control system,

Fig. 2

schematically a universal scaffold, and

Fig. 3

a profile of a double-T beam.

The rolling train 1 shown only partially in FIG. 1 is for the production of a profiled rolling stock provided. For this purpose, the rolling mill 1 comprises a plurality from in a direction of advance or rolling direction symbolized by arrow 2 successive rolling stands, of which only a first one in FIG. 1 Roll stand 4, a second roll stand 6 and a third roll stand 8 each are indicated are represented by their rollers. In addition to the rolling stands 4, 6, 8 can further roll stands before or within the rolling mill 1 downstream. In particular, the first roll stand 4 in Rolling direction x seen a rough or roughing stand before and the third stand 8 seen in the rolling direction x a fine rolling mill downstream.

The roll stands 4 and 8 are in the exemplary embodiment according to FIG. 1 as so-called Universal scaffolding designed. For this purpose, the first roll stand 4 includes a Pair of vertically stacked horizontal rollers 10, 12, together a roll gap extended in the vertical direction for the to be carried out Form rolling stock. The horizontal rollers 10, 12 are over roller axes 14 or 16 rotatably supported in scaffolding elements in a manner not shown. Furthermore, the first roll stand 4 comprises a pair of vertical rolls 18, 20 which offset laterally from the guideway for the rolling stock between the horizontal rolls 10, 12 are arranged. The vertical rollers 18, 20 each form one Roll gap, on the one hand by its tread and on the other hand by the side surfaces the horizontal rollers 10, 12 is limited. In an analogous way, this includes Roll stand 8, also designed as a universal stand, has a pair of horizontal rolls 22, 24 and a pair of vertical rollers 26, 28.

For further clarification, the first roll stand, designed as a universal stand, is 4 shown schematically in section in FIG. 2. In particular, it can be seen that the horizontal rolls 10, 12 form a roll gap 30 which is the web thickness a continuous double T-beam determined as rolling stock. The horizontal roller 10 is with its roller axis 14 in each end in a hydraulic cylinder unit 32 or 34 stored. The hydraulic cylinder units 32, 34 are in not shown in detail on a scaffold stand and fixed for adjustment a working medium can be applied to a roller position. The application of the hydraulic cylinder units 32, 34 takes place via a in FIG. 2 Not shown actuator that the pressure of the working medium in the Hydraulic cylinder units 32, 34 depending on a predetermined input value established. The input value can be a target position for the horizontal roller 10 or a target value for a rolling force with which the horizontal roller 10 acts on a rolling stock guided through the roll stand 4. In The second horizontal roller 12 is of an analogous configuration over its roller axis 16 each end mounted in a hydraulic cylinder unit 36 or 38.

As can be seen from FIG. 2, the vertical rollers 18, 20 are on both sides of the horizontal rollers 10, 12 and arranged between their roller axes 14, 16. The Vertical rollers 18, 20 each form together with those assigned to them Side surfaces of the horizontal rollers 10, 12 a horizontally extended nip 39, with both nips 39 together with the bale length of the horizontal rolls 10, 12 the width B of the rolling stock passed through the roll stand 4 specify. The vertical rollers 18, 20 are each via a holder element 40 or 42 and a hydraulic cylinder unit 44 or 46 associated therewith on one Roll stand stored.

That seen in the rolling direction x between the first roll stand 4 and the third Roll stand 8 switched second roll stand 6 only includes in the embodiment a pair of horizontal rollers 50, 52. The horizontal rollers 50, 52 are seen longer in its longitudinal direction than the horizontal rollers 10, 12, 22, 24 of the first roll stand 4 or the third roll stand 8.

In its entirety, the part of the rolling train 1 shown in FIG. 1 is for production of a rolled stock profiled as a double-T beam. Profile 54 of such a double-T beam is in Fig. 3, specifying the relevant parameters shown. The profile 54 of the double-T beam has in his Center region on a web 56, which is characterized by its web width S. A flange 58 or 60 is formed on each end of the web 56. Any flange 58, 60 is characterized by its flange height, which in Fig. 3 by the Double arrow 62 is indicated. In addition, the flanges 58, 60 are by their respective Characterized flange thickness FD. For a complete description of profile 54 in addition to its overall width B, the positioning of the web 56 is then also used relative to the top or bottom edge of the flanges 58, 60. This positioning is characterized by the position L.

In their entirety, these will characterize the profile 54 of the rolling stock Operating parameters influenced by the roll stands 4, 6, 8 of the rolling mill 1 as follows: the web width S of the web 56 is essentially determined by the Roll gap 30 of the horizontal rolls 10, 12 of the first roll stand 4 or of the horizontal rolls 22, 24 of the third roll stand 8. For the finally completed The rolled product is in particular the roll gap of the horizontal rolls 22, 24 of the last time passed through mill stand 8. The width B of the profile 54 is given by the sum of the roll gaps 39 of the vertical rolls 18, 20 of the first roll stand 4 or the vertical rolls 26, 28 of the third roll stand 8, plus the bale length of the respective horizontal rollers 10, 12 or 22, 24. Again, the final width B of the rolled profile 54 is essentially determined by the mentioned parameters of the last run third roll stand 8. The flange height FH is in turn essentially determined through the roll gap of the horizontal rolls 50, 52 of the second roll stand 6.

The rolling mill 1 is for a particularly precise compliance with a given Target profile, i.e. for compliance with particularly low tolerance limit values, at the Production of a profiled rolling stock designed. For this, the Walzstrasse 1 is a Control system 70 assigned. Control system 70 includes a central one Control unit 72, the output side with a number of actuating elements 74, 76, 80 for the roll stands 4, 6, 8 is connected. The control unit is on the input side 72 with a measuring device 82 for determining a profile characteristic of the Rolled goods connected. Furthermore, the control unit 72 is a memory module 84, which the control unit 72 accesses for reading out or storing data can, as well as an input-output module 86, for example a personal computer, assigned.

The actuating element 74 is assigned to the first roll stand 4. The actuator 74 gives control values to the hydraulic cylinder units 32, 34, 36, 38, 46, 48 of the a total of four horizontal rolls 10, 12 and vertical rolls 18, 20 of the first Roll stand 4 out. This is indicated by the four outgoing arrows. To generate the control values, the control element 74 is in sub-groups or Structured modules, each one of the horizontal rollers 10, 12 or the vertical rollers 18, 20 is assigned. This is analogous to this the third rolling stand 8 is assigned the control element 80.

Furthermore, in the exemplary embodiment, the roll stand 6 has two independently of mutually adjustable horizontal rollers 50, 52. Accordingly, in the embodiment each horizontal roller 50, 52 has a module of the actuating element 76 assigned.

During the operation of rolling mill 1, the control unit 72 gives setpoints SW for the operating parameters of the roll stands 4, 6, 8 to the actuating elements assigned to them 74, 76, 80 from. The control unit 72 is responsible for the profile 54 characteristic parameters designed as reference variables. Here are in the embodiment the parameters relating to the horizontal rolls 10, 12 are coupled, the setting of the roll gap 30 being substantially symmetrical a reference plane predetermined by the rolling stock plane. The application the horizontal rollers 10, 12 thus take place with a single, coupled one Setpoint SW for the roll gap 30, as indicated by the bracket between is symbolized in the first two modules. Alternatively, one can Independent loading of the horizontal rollers 10, 12 with control values is provided his. Accordingly, the control unit 72 outputs, for example the control element 74 assigned to the first roll stand 4 has a target value for the by the horizontal rolls 10, 12 formed nip 30 and one each further setpoint SW for each vertical roller 18, 20.

The control element 74 is in the manner of a subordinate controller hierarchy level to convert these setpoints into suitable manipulated variables for the assigned first roll stand 4 formed. Based on the supplied setpoints SW, the control element 74 thus converts the setpoint for the operating parameter "Roll gap 30" (corresponding to the web thickness S of the double-T beam) in suitable control values for the positioning of the horizontal rollers 10, 12 and / or their rolling forces around. These control values can be set within the control element 74 in the type of a further subordinate rule hierarchy again in suitable Control values for the actual control variable, namely in particular the pressure of the working medium in the hydraulic cylinders 32, 34, 36, 38, are implemented. In Analogously, the control unit 72 gives setpoints SW for the roll gap of the horizontal rolls 22, 24 and the vertical rollers 26, 28 to the third roll stand 8 assigned actuator 80 from.

The control unit 72 outputs setpoints SW for the vertical to the actuating element 76 Positioning of the respective horizontal roller 50, 52. In the control element 76 in an analogous manner, initially a conversion of the supplied setpoints SW into the actual control values, namely in particular the pressures for the supplied Hydraulic cylinder.

In order to promptly comply with the tolerance limit values within the rolling mill 1 To ensure in the production of the profiled rolling stock is Control unit 72 for a result-oriented correction of the target values SW taking into account based on experience with previous rolling processes. The profile is measured via the measuring device 82 during operation of the rolling mill 1 of the rolling stock running out of the third roll stand 8 is determined, for example based on a profile characteristic or a plurality of profile characteristics. The profile parameters can in particular be measured values for the actually present Web thickness S, the actual flange height FH and / or the actual one existing flange thicknesses FD. The thus determined profile of the expiring Rolled stock is controlled by the control unit 72 with, for example, a Storage module 84 stored target profile for the rolling stock being compared. Based on this comparison, a discrepancy between the actual present (actual) rolling result and the predetermined (target) rolling result are closed. If this deviation is a predetermined, comparatively narrow Tolerance limit exceeds, then a correction is made by the control unit 72 provided to the control elements 74, 76, 80 setpoint values SW. The Post-correction takes place in the manner of an "online correction" during the affected rolling process, the relative position-dependent parameter changes can be taken into account within a single rolling stock. Thus includes the post correction essentially two posts, with the first post in the Kind of a "presetting" or a pre-setting during the rolling process is kept constant, and the second contribution being an "online correction" is tracked during the rolling process.

When correcting the target values SW, it is taken into account that each roll stand 4, 6, 8 can contribute to a deviation and thus to a rolling error independently of the others. However, all such error contributions are present in a cumulative form in the rolling stock running out of the third roll stand 8 and are therefore also accumulated by the measuring device 82. In order to enable error compensation close to the cause and thus compliance with particularly narrow tolerance limits while saving additional measuring devices for determining the profile of the rolling stock, the control unit 72 is designed for weighted compensation of the accumulated rolling error determined by the measuring device 82. The compensation of the rolling error is therefore carried out by modifying the setpoints SW, with each setpoint SW being subjected to a correction setpoint K _i on the basis of the discrepancy between the actual state and the setpoint state and taking into account a stand-specific weighting factor. In other words: the presetting part of the correction setpoint K _i provided for the modification of the setpoint SW for the ith mill stand 4, 6, 8 depends on the one hand on the deviation of the actual state from the setpoint condition on the rolled stock and on the other hand also on one each roll stand 4, 6, 8 specifically assigned weighting factor W _i . Thus, even if only a global error characteristic is present as a result of the measurement in the measuring device 82, an individualized and targeted error compensation is made possible.

The stand-specific weighting factors W _i , which are stored in an updated form on the storage module 84, contain experience from the relative error proportion of the respective roll stand 4, 6, 8 in past rolling processes. Furthermore, the type and type of the rolling stock is taken into account in the weighting factors W _i . In other words: for each type of rolling stock, a separate, individual set of stand-specific weighting factors W _i for the rolling stands 4, 6, 8 is stored in the storage module 84. The weighting factors W _i are regularly updated in the manner of a "learning function", with new or additional experiences from recent rolling results being incorporated.

In the case of those roller pairs whose individual rollers can be adjusted independently of one another, their setpoints are also updated, taking into account a roller-specific weighting factor W _i . In other words, the setpoints SW for the respective individual rolls which can be set independently of one another are subjected to a correction value K _i which depends both on the deviation of the actual profile from the set profile as well as on the stand-specific weighting factor W _i and on the roll-specific weighting factor W _i . Since, for example, the coupled setpoint value SW assigned to the horizontal rollers 10, 12 is converted into individual actuating values in the actuating element 74, the actuating element 74 is connected to the memory module 84 in a manner not shown in order to take the roller-specific weighting factors W _i into account. The same also applies to the adjusting elements 76, 80.

The part of the rolling mill 1 shown in the exemplary embodiment according to FIG. 1 is especially for use in a so-called rev rolling process for profiled Suitable for rolling stock. Passes through in such a reves rolling process the rolling stock the roll stands 4, 6, 8 several times. This occurs on the first pass Rolled stock in the first roll stand 4 and passes through the one after the other Roll stands 4, 6, 8. After emerging from the third roll stand 8, the Rolled material stopped and in the opposite direction through the roll stands 8, 6, 4 guided. For each such run, referred to as the "stitch", the corresponding runs Operating parameters of the roll stands 4, 6, 8 readjusted, whereby in particular a gradual reduction of the roll gaps for so long until an overall intended thickness or width reduction occurs is. After completing this multiple in the manner of a pendulum-like movement In the end, the rolling stock ends in the original rolling direction the third roll stand 8 and can be fed to a further treatment.

In such a reversing rolling method in particular, a timely update of the setpoints SW by the control unit 72 is helpful with regard to a particularly precise rolling result. The actual profile can be determined in particular each time the rolling stock passes the measuring device 82, depending on the passage or pass, and compared with the target profile for the respective pass or pass. This means that deviations from the target condition can be recognized and compensated for early on in the rolling stock being processed during the rolling process. For this purpose, the correction values K _i for the desired values SW are determined in the control unit 72 for the upcoming run on the basis of the results of the previous runs. The result of the immediately preceding run is of particular importance. The weighting factors W _{i take into} account on the one hand the contribution of the respective roll stand 4, 6, 8 to the rolling error that has occurred, but on the other hand also take special account of the passage just undertaken or to be carried out.

LIST OF REFERENCE NUMBERS

1

rolling train

2

arrow

4, 6, 8

rolling mills

10, 12

horizontal rolls

14, 16

roll axes

18, 20

vertical rolls

22, 24

horizontal rolls

26, 28

vertical rolls

30

nip

32, 34, 36, 38

Hydraulic cylinder units

39

nips

40, 42

holder element

44, 46

Hydraulic cylinder units

50, 52

horizontal rolls

54

profile

56

web

58, 60

flange

62

double arrow

70

control system

72

control unit

74, 76, 80

actuators

82

measuring device

84

memory module

86

An output module

B

overall width

FD

flange

FH

Flange

L

camp

K _i

Correction setpoint

S

web width

SW

setpoints

W _i

Weighting factor

X

Direction of advance or rolling direction

Claims (9)

Method for operating a rolling train (1) for profiled rolling stock, in which the rolling stock is guided through a number of rolling stands (4, 6, 8) which follow one another in a rolling direction (x) and each comprise a number of work rolls, each rolling stand (4 , 6, 8) is set to a number of target values (SW) with regard to its operating parameters,
characterized in that the profile (54) of the rolling stock being discharged is compared and compared with a target profile, the or each target value (SW) of the or each roll stand (4, 6, 8) being referred to a stand-specific weighting factor (W _i ) the deviations of the determined profile from the target profile are subjected to a correction target value (K _i ). Method according to claim 1,
characterized in that a setpoint (SW) for a web thickness and / or a flange height and / or a flange thickness of the rolling stock is specified for the or each roll stand (4, 6, 8). The method of claim 1 or 2,
characterized in that the respective stand-specific weighting factor (W _i ) is predetermined as a function of the rolling stock. Method according to one of claims 1 to 3,
characterized in that the rolls of a roll stand (4, 6, 8) are operated independently of one another on the basis of roll-specific setpoints (SW), the or each setpoint (SW) of a roll with reference to a roll-specific weighting factor (W _i ) on the basis of the deviations of the determined profile (54) is acted upon by the target profile with a correction target value (K _i ). Method according to one of claims 1 to 4,
characterized in that the or each correction setpoint (K _i ) is limited to a parameter-specific maximum value. Method according to one of claims 1 to 5,
characterized in that the or each correction setpoint (K _i ), in particular the stand-specific weighting factor (W _i ), is predetermined on the basis of the rolling result of previous rolling processes. Method according to one of claims 1 to 6,
characterized in that when the rolling stock passes through the rolling train (1) several times, the respective correction setpoint (K _i ) is specified taking into account the rolling result of a previous pass. Method according to one of claims 1 to 7,
characterized in that a correction setpoint (K _i ) for a horizontal adjustment of a roll stand (4, 6, 8) and a correction setpoint (K _i ) for a vertical adjustment of a roll stand (4, 8) is specified, the ratio of these correction setpoints (K _i ) is limited to a predeterminable maximum value. Control system for a rolling mill (1) for profiled rolling stock, in which the rolling stock is guided through a number of rolling stands (4, 6, 8) which follow one another in a rolling direction (x) and each comprise a number of work rolls, with a control unit (72) which specifies a setpoint (SW) for an operating parameter for an actuating element (74, 76, 80) assigned to a roll stand (4, 6, 8),
characterized in that the control unit (72) is connected on the input side to a measuring device for determining a profile characteristic of the rolling stock being discharged and to a storage module (84), the control unit (72) being the setpoint (SW) of the respective rolling stand (4, 6, 8 ), with reference to a framework-specific weighting factor (W _i ) stored in the memory module (84), with the correction setpoint (K _i ) based on the deviations of the determined profile characteristic value from a target profile characteristic value.

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