EP2162245B1 - Rolling of a strip in a rolling train using the last stand of the rolling train as a tension reducer - Google Patents

Description

• wobei die Walzstraße mehrere Hauptwalzgerüste und einen den Hauptwalzgerüsten nachgeordneten Haspel aufweist,
• wobei die Hauptwalzgerüste jeweils Arbeitswalzen und zumindest Stützwalzen aufweisen,
• wobei einer Steuereinrichtung der Walzstraße Daten des Bandes zugeführt werden, die zumindest eine von Null verschiedene Gesamtstichabnahme festlegen, um welche eine Anfangsdicke des Bandes in der Walzstraße reduziert werden soll,
• wobei die Steuereinrichtung anhand der ihr zugeführten Daten für die Hauptwalzgerüste Einzelstichabnahmen ermittelt,
• wobei die Steuereinrichtung die Hauptwalzgerüste und den Haspel derart steuert, dass das Band in den Hauptwalzgerüsten entsprechend den ermittelten Einzelstichabnahmen gewalzt und sodann vom Haspel aufgehaspelt wird,

The present invention relates to an operating method for a rolling line for rolling a strip, in particular a metal strip,

• wherein the rolling train comprises a plurality of main rolling stands and a reel downstream of the main rolling stands,
• the main rolling stands each having work rolls and at least back-up rolls,
• wherein a control device of the rolling train data of the band are supplied, which determine at least a non-zero total stitch loss by which an initial thickness of the strip is to be reduced in the rolling mill,
• wherein the control device determines single-stitch decreases on the basis of the data supplied to it for the main rolling stands,
• wherein the control means controls the main rolling stands and the reel such that the strip in the main rolling stands is rolled in accordance with the determined single-stitch decreases and then reeled by the reel,

The present invention further relates to a rolling mill control program of the type described above, the control program comprising machine code, the execution of which by the control means causes the control means to operate the rolling mill in accordance with an operating method of the above type.

Furthermore, the present invention relates to a data carrier on which such a control program is stored in machine-readable form.

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

Finally, the present invention relates to a rolling mill with a plurality of main rolling stands, a main rolling mill downstream reel and a control device, wherein the main rolling stands each have work rolls and back-up rolls and the control device is designed such that it operates the rolling mill according to an operating method of the type described above.

The objects described above are well known.

The main mills are usually quarto or sexto scaffolding. This is also the main design case in the context of the present invention. However, other embodiments are possible. Excluded are only pure duo scaffolding, which have no other rollers except the work rolls.

From the WO 99/51368 A1 a Steckel mill is known which has two rolling stands, which are preceded by a coiler furnace and a further coiler oven downstream. Each of the rolling stands is designed as a quarto scaffolding. To adjust the temperature of the coiled tape, the tape is rewound with the lowest possible stitch loss - if possible with stitch loss zero.

From the DE 42 43 045 A1 It is known to adjust between the rolling stands of a rolling train with each other and between the rolling stands and the reels a regulated strip tension.

When rolling tapes together with subsequent coiling, the pull in front of the reel should in some cases be as low as possible, since otherwise there is a risk that the individual layers of the reeled coil (coil) stick together. Before and also behind the last rolling stand in which the strip rolled is (ie, reduced in thickness), the tape should, however, have a strip tension for technical reasons.

In the prior art, various measures are known for decoupling of the train in the band before the reel and the train in the band behind the last main roll stand in which the strip is rolled.

For example, one known measure is to provide an S-roll set between the last main roll stand in which the strip is rolled and the reel. Another known measure is, for example, to provide a driver instead of the S-roller set. The driver can be designed in individual cases as a duo-scaffolding, the tape is not rolled in the duo-scaffolding, but only driven.

The above-mentioned, known measures can be realized very easily when a rolling mill is rebuilt. In existing rolling mills, however, the measures - especially for reasons of space - only with difficulty, only with larger conversions (including the associated costs) or not feasible.

The object of the present invention is to provide articles, by means of which a decoupling of the train in the belt in front of the reel and the train, with which the belt from the last main roll stand in which the strip is rolled, can be achieved. In this case, the decoupling should - at least in terms of approach - also be feasible in existing systems in which the known measures of the prior art are not feasible.

The object is achieved by an operating method having the features of claim 1, a control program having the features of claim 9, a data carrier on which such a control program is stored, a rolling mill controller having the features of claim 11 and a rolling train solved with the features of claim 12. Advantageous embodiments are the subject of the dependent claims 2 to 8.

According to the invention, the control device determines the single-stitch decreases such that the single-stitch decrease of the main rolling stand immediately preceding the reel is zero. Furthermore, the control device controls the reel main upstream main roll stand such that - based on this main roll stand - the outlet side train in the band is smaller than the inlet side train, but the band passes through this main rolling mill over the bandwidth seen at least one transformation.

The band may be any bandwidth, for example broadband (bandwidth 1200 mm and more). As a rule, however, it is a narrow band (width 800 mm and less). Often, the band is formed by splitting a broadband (for example, a broadband of 1500 mm width is divided into two narrow bands of 750 mm width each). In particular, in this case, the band often already before rolling in the rolling mill on a spline.

Preferably, the control device controls the reel main immediately upstream of main mill stand such that the band passes through this main rolling mill over its entire width without deformation. For bands with - over the bandwidth seen - even or at least symmetrical thickness course this is easily possible. However, the latter approach is also desirable if the band has a spline. In this case, for example, the work rolls of the relevant main rolling stand can be seen in the direction of tape travel pivoted against each other and / or be seen in the band thickness direction employed in a spline.

The tape should continue to run out of the reel immediately upstream main rolling mill. The just leaving From this main rolling stand is particularly important, as long as the reel has not yet gripped the tape. Also, the correct direction of the tape can be achieved that the work rolls of the relevant main rolling stand are pivoted against each other or employed in a spline.

The band is often made of steel. Steel can alternatively be cold rolled or hot rolled. In some cases, the present invention can be applied to hot rolling. As a rule, however, the strip is cold rolled in the rolling mill.

The number of main rolling stands is in principle arbitrary. At least it is two. As a rule, it is between four and seven.

The control device preferably controls the main rolling stand, which is directly preceded by the reel, with rolling force control. In this case, the control device determines a nominal rolling force of this main rolling stand such that the strip passes through this main rolling stand without deformation.

FIG 1

eine Walzstraße mit Hauptwalzgerüsten, einem Haspel und einer Steuereinrichtung,

FIG 2

ein Hauptwalzgerüst und ein Band in Bandlaufrichtung gesehen,

FIG 3

ein Ablaufdiagramm,

FIG 4

das letzte Hauptwalzgerüst in Bandlaufrichtung gesehen und

FIG 5

das letzte Hauptwalzgerüst in perspektivischer Darstellung.

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

FIG. 1

a rolling mill with main rolling stands, a reel and a control device,

FIG. 2

a main roll stand and a strip seen in the strip running direction,

FIG. 3

a flow chart,

FIG. 4

the last main rolling stand seen in the direction of tape travel and

FIG. 5

the last main rolling stand in perspective view.

According to FIG. 1 a rolling mill according to the invention comprises a plurality of main rolling stands 1, 1 ', a reel 2 and a control device 3 on. The main rolling stands 1, 1 'are successively passed through by a belt 4 and then reeled by the reel 2. The control device 3 controls the main rolling stands 1, 1 'and the reel.

The number of main rolling stands 1, 1 'is usually four to seven. At least it is two. The main mills 1, 1 'are usually (see also FIG. 1 ) formed as quarto scaffolds. So they each have work rolls 5, 5 'and back-up rolls 6, 6'. Alternatively, they may additionally have additional rollers, for example in the case of training as a six-high scaffolding intermediate rolls.

The reel 2 is the last main rolling stand 1 'immediately downstream. The term "immediately downstream" in this case means that there is no element between the last main rolling stand 1 'and the reel 2 with which a tension Z prevailing in the belt 4 can be influenced to a significant degree. However, one or more deflection rollers 7 can be arranged between the last main rolling stand 1 'and the reel 2.

The last main rolling stand 1 'is of particular importance in the context of the present invention. For this reason, it was - in contrast to the other main rolling stands 1 - provided with its own reference numeral, namely the reference numeral 1 '. Other sizes, insofar as they relate specifically to the last main rolling stand 1 ', are subsequently provided with an apostrophe. A further significance is not the distinction.

The rolled strip 4 in the rolling train is usually a metal strip, for example a steel strip. The band 4 may be a band 4 of arbitrary width b, for example broadband, ie a band 4 having a bandwidth b of at least 1200 mm. In general, however, the band 4 is according to FIG. 2 a narrow band, whose bandwidth b is a maximum of 800 mm. In most cases, the bandwidth b is even less than 600 mm or less than 700 mm.

Especially in the case of narrow band, the band 4 may have a spline already before rolling in the rolling mill. It is thus possible that the band 4 has on one side a larger band thickness d1 than on the other side, where it has a smaller band thickness d2. The representation in FIG. 2 This is exaggerated.

The band 4 is cold rolled in the rolling mill usually. In some cases, however, hot rolling is also possible.

The control device 3 controls, as already mentioned, the main rolling stands 1, 1 'and the reel 2. The term "control" is to be understood in a comprehensive sense, i. in the sense of influencing the operating state of Walzstra βe. On the other hand, the term "taxes" should not be understood as a contrast to the term "rules".

The controller 3 comprises basic automation (i.e., simple controllers for, for example, roller speeds, nips, rolling forces, etc.) and a superimposed control system. In the context of the present invention, it depends on the superimposed control system.

The control device 3 is usually designed as a software programmable device. It is fed to a control program 8. The feeding of the control program 8 can take place, for example, via a network connection (LAN, Internet,...) Or via a data carrier 9, on which the control program 8 is stored. As a disk 9, for example, a CD-ROM (see FIG. 1 ), a USB memory stick or a memory card in question.

The control program 8 comprises machine code 10, ie program instructions which can be executed directly and directly by the control device 3. The control program 8 can - for example from an operator 11 of the rolling mill - in the usual way (mouse click, etc.) are called. Due to the call, it is executed by the controller 3. The execution of the control program 8 by the control device 3 causes the control device 3 to operate the rolling mill in accordance with an operating method which is described below in connection with FIG FIG. 3 is explained in more detail.

miteinander verknüpft.According to FIG. 3 takes the controller 3 in a step S1 data of the tape 4 contrary, which are supplied to the control device 3. The data include, for example, information on the bandwidth b, the initial strip thickness d-in, a target final thickness d-out, an initial temperature T and a chemical composition of the belt 4. In particular, the data supplied to the control device 3 implicitly or explicitly imposes an overall stitch decrease A by which the initial thickness d-in of the strip 4 in the rolling train is to be reduced. The total decrease A is - of course - greater than zero. The total stitch loss A, the initial strip thickness d-in, and the target final thickness d-out are here according to the relationship $$\mathit{A}\mathit{=}1\mathit{-}\frac{\mathit{d}\mathit{-}\mathit{out}}{\mathit{d}\mathit{-}\mathit{in}}$$

linked together.

In a step S2, the control device 3 uses the data d-in, d-out, b, T supplied to it for the main rolling stands 1, 1 'to determine single-stitch decreases a, a'. The single-stitch decreases a, a 'are hereby defined analogously to the total stitch decrease A, wherein, however, the input and output thicknesses refer to the respective main roll stand 1, 1'. The single stitch decreases a, a 'are of course determined by the control device 3 in the context of step S2 such that they correspond in total to the total stitch decrease A.

According to the invention, the control device 3 sets the single-stitch decrease a 'for the last main rolling stand 1' to the value zero. This is in contrast to so-called skin passformers. Because in skin pass mills, the single-stitch decrease a 'of the last main rolling mill 1' is relatively small (for example, only 1%), but greater than zero.

The other single-stitch decreases a determines the control device 3 in the context of step S2 as needed. In principle, the determination of the other single-stitch decreases a such as if the last main roll stand 1 'simply would not exist.

It is possible that the step S2 is always and always carried out as described above. It may alternatively be modified in that the control device 3 first tries to distribute the total stitch decrease A to the main rolling stands 1 with the exception of the last main rolling stand 1 '. If this is possible, step S2 is executed as explained above. Otherwise, the band 4 can only be properly rolled if the single stitch decrease a 'of the last roll stand 1' is greater than zero. In such a case, either the single-stitch decrease a 'may be chosen as small as possible or determined in the usual way.

In a step S3, the control device 3 controls the main rolling stands 1, 1 'and the reel 2. The control takes place in such a way that the strip 4 is rolled in the main rolling stands 1, 1 'in accordance with the determined single-stitch decreases a, a' and then reeled up by the reel 2. The control device 3 in this case controls the last main rolling stand 1 'such that - based on the last main rolling stand 1' of the outlet side train Za in the band 4 is smaller than the inlet side train Ze. However, the drive continues to be such that the belt 4 passes through the last main rolling stand 1 'at least one side without deformation.

The case that the band 4 passes through the last main rolling stand 1 'only on one side, but not over its entire width b without deformation, may be required in individual cases, if the band 4 has a spline. If, on the other hand, the band 4 does not have such a spline profile, it is readily possible for the control unit 3 to drive the last rolling stand 1 'in such a way that the band 4 passes through the last main rolling stand 1' over its entire width b (cf. FIG. 4 ). This procedure is also preferred if the band 4 has the above-mentioned spline profile. To reach this state, it can - see FIG. 5 - Be necessary, the work rolls 5 'of the last main roll stand 1' by means of the control device 3 to control such that the work rolls 5 'seen in the tape running direction x are pivoted against each other. Alternatively or additionally, the work rolls 5 'seen in the strip thickness direction can be employed in a spline (see FIG. 4 ).

In order to achieve that the band 4 passes through the last rolling stand 1 'without deformation, a rolling force F', with which the last rolling stand 1 'acts on the band 4, must not be too large. The rolling force F 'must therefore be below an upper limit S. On the other hand, in order to be able to achieve that the outlet-side train Za is decoupled from the inlet-side train Ze, the rolling force F 'must be above a lower barrier S'. The control device 3 therefore preferably controls the last rolling stand 1 'with rolling force control. The target rolling force F '* for the last main rolling stand 1' is determined here by the control device 3 such that it lies between the lower barrier S 'and the upper barrier S.

The stable operation of the rolling train has been described above, in which the strip 4 is rolled, on the one hand, in the main rolling stands 1, 1 'and, on the other hand, is coiled by the reel 2. The following is the case that occurs at the beginning of the rolling process. In this case, the term "start of the rolling process" refers to the time until the time when the reel 2 grips the band 4.

During the above period, it is possible that the expiring from the last main rolling stand 1 'band 4 migrates laterally. In order to prevent such lateral emigration, the control device 3 controls the last main rolling stand 1 'accordingly. In particular, the control device 3 can control the last main rolling stand 1 'in such a way that the work rolls 5' of this main rolling stand 1 'are pivoted relative to one another in the direction of strip movement x. Alternatively or additionally, it is possible for the control device 3 to drive the last main rolling stand 1 'in such a way that the work rolls 5' of this main rolling stand 1 'form a splined profile as seen in the strip thickness direction. By one and by both measures can be effected that the tape 4 from the last main rolling stand 1 'just expires.

The embodiments according to the invention have many advantages. In particular, it is also possible to retrofit existing rolling mills in such a way that they can be operated in the manner according to the invention, at least in a large number of cases (namely, when the total stitch loss A is small enough).

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 (12)

1. Operating method for a rolling train for the rolling of a strip (4), in particular a metal strip (4),

   - the rolling train having a number of main rolling stands (1, 1') and a coiler (2) arranged downstream of the main rolling stands (1, 1'),

   - the main rolling stands (1, 1') respectively having work rolls (5, 5') and at least backing rolls (6, 6'),

   - data (d-in, d-out, b, T) of the strip (4), which establish at least an overall pass reduction (A) other than zero by which an initial thickness (d-in) of the strip (4) is to be reduced in the rolling train, being fed to a control device (3) of the rolling train,

   - the control device (3) determining individual pass reductions (a, a') for the main rolling stands (1, 1') on the basis of the data fed to it,

   - the control device (3) controlling the main rolling stands (1, 1') and the coiler (2) in such a way that the strip (4) is rolled in the main rolling stands (1, 1') in a way corresponding to the individual pass reductions (a, a') determined and is then coiled up by the coiler (2),
   characterized

   - in that the control device (3) determines the individual pass reductions (a, a') in such a way that the individual pass reduction (a') of the main rolling stand (1') arranged directly upstream of the coiler (2) is zero, and

   - in that the control device (3) controls the main rolling stand (1') arranged directly upstream of the coiler (2) in such a way that - with respect to this main rolling stand (1') - the tension (Za) in the strip (4) on the outlet side is less than the tension (Ze) on the inlet side, but the strip (4) runs through this main rolling stand (1') without undergoing forming, at least on one side, as seen over the band width (b).
2. Operating method according to Claim 1, characterized in that the strip (4) is a narrow strip.
3. Operating method according to Claim 1 or 2, characterized in that the strip (4) has a wedge profile before the rolling in the rolling train.
4. Operating method according to Claim 1, 2 or 3, characterized in that the control device (3) activates the main rolling stand (1') arranged directly upstream of the coiler (2) in such a way that the strip (4) runs through this main rolling stand (1') without undergoing forming over its entire width (b).
5. Operating method according to one of the above claims, characterized in that, at least at the beginning of the rolling of the strip (4), the control device (3) activates the main rolling stand (1') arranged directly upstream of the coiler (2) in such a way that at least the work rolls (5') of this main rolling stand (1') are pivoted with respect to one another, as seen in the strip running direction (x), and/or are set in a wedge profile, as seen in the strip thickness direction, in such a way that the strip (4) runs out straight from this main rolling stand (1').
6. Operating method according to one of the above claims, characterized in that the strip (4) is cold-rolled in the rolling train.
7. Operating method according to one of the above claims, characterized in that the number of main rolling stands (1, 1') is at least four.
8. Operating method according to one of the above claims, characterized in that the control device (3) controls the main rolling stand (1') arranged directly upstream of the coiler (2) in such a way as to regulate the rolling force and in that the control device (3) determines a desired rolling force (F'* of this main rolling stand (1') in such a way that the strip (4) runs through this main rolling stand (1') without undergoing forming.
9. Control program for a control device (3) of a rolling train, the rolling train having a number of main rolling stands (1, 1') and a coiler (2) arranged downstream of the main rolling stands (1, 1') and the main rolling stands (1, 1') respectively having work rolls (5, 5') and at least backing rolls (6, 6'), the control program comprising machine code (10) which, when executed by the control device (3), has the effect that the control device (3) operates the rolling train according to an operating method according to one of Claims 1 to 8.
10. Data carrier on which a control program (8) according to Claim 9 is stored in a machine-readable form.
11. Control device for a rolling train, the rolling train having a number of main rolling stands (1, 1') and a coiler (2) arranged downstream of the main rolling stands (1, 1') and the main rolling stands (1, 1') respectively having work rolls (5, 5') and at least backing rolls (6, 6'), the control device being formed in such a way that it operates the rolling train according to an operating method according to one of Claims 1 to 8.
12. Rolling train with a number of main rolling stands (1, 1'), a coiler (2) arranged downstream of the main rolling stands (1, 1') and a control device (3), the main rolling stands (1, 1') respectively having work rolls (5, 5') and at least backing rolls (6, 6'), the control device (3) being formed according to Claim 11.

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