EP0972581B1 - Rolling method for bar-shaped rolling stock, in particular steel bars and wire - Google Patents

Abstract

The actual rolling force and the resultant roll gap increase are determined. A roll gap correction is determined on the basis of this roll gap increase and a target roll gap in such a way that the actual roll gap approximates the target roll gap. The roll gap correction is implemented within a roll stand control interval.

Description

The present invention relates to a rolling process for rod-shaped rolling stock, in particular bar steel or wire, in one Roll stand with two relative to each other in a Anstellrichtung adjustable work rolls, which together have a rolled caliber with a Form actual nip, so that the rolling stock from the rolling mill with an actual height and an actual width at a rolling speed runs out, wherein the rolling stock is rolled with an actual rolling force (see, for example, JP-A-590 544 12).

Such rolling processes are known. You work, for example, on the Basis of a so-called monitor control. These are deviations detected in the height and the width of the rod-shaped rolling stock and on the basis of an electromechanical or hydromechanical employment corrected. Such systems have the disadvantage that both the Monitor control itself as well as employment very slow. In addition, there is the time delay due to the measurement behind the last controlled scaffolding. The result is a reaction time of about 3 seconds, so only interference with a low Frequency are adjustable. Short-term disturbances, e.g. by so-called Skidmarks are not predictable, which may be too Tolerance violations leads. The same problem arises in case of faults that start at the rolling stock or at the rolling stock end Temperature and thickness variations are caused.

The present invention has set itself the task of a rolling process for rod-shaped rolling to create, which significantly works faster and with the so also short-term disturbances are adjustable.

• daß die Arbeitswalzen über eine Hydraulikzylindereinheit anstellbar sind,
• daß die Ist-Walzkraft erfaßt wird,
• daß anhand der Ist-Walzkraft eine walzkraftbedingte Walzspaltauffederung bestimmt wird,
• daß anhand der walzkraftbedingten Walzspaltauffederung und einem Soll-Walzspalt ein Walzenanstellungs-Korrekturwert derart bestimmt wird, daß der Ist-Walzspalt dem Soll-Walzspalt angenähert wird, und
• daß eine Walzenanstellung innerhalb einer Gerüstregelzeit um den Walzenanstellungs-Korrekturwert geändert wird.

The task is solved by

• that the work rolls are adjustable via a hydraulic cylinder unit,
• that the actual rolling force is detected,
• that a roll-force-induced roll gap deflection is determined on the basis of the actual rolling force,
• in that a roll adjustment correction value is determined in such a way that the actual roll gap is approximated to the target roll gap on the basis of the roll force-induced roll gap suspension and a set roll gap, and
• that a roll adjustment is changed within a skeleton control time by the roll adjustment correction value.

Such methods have been for rolling tapes for years known. They are highly developed. They care independently of the Rolling force for an actual rolling gap corresponding to the desired rolling gap. However, the methods have been used for rolling rod-shaped rolling stock considered not applicable. The reason for this is that when rolling From the band, the width of the rolling stock is constant from the outset. at rod-shaped rolling, on the other hand, automatically becomes too by rolling changed the width of the rolling stock. A simple transfer of For the rolling of tape known method would therefore be inadmissible Width tolerances result. On the other hand, in the present invention the method is used to calculate the difference between a Parent control method determined target roll gap and a Actual roll gap to minimize as quickly as possible. This will be the Application of the known thickness rules for bar steel and Wire routes enabled.

When the rolling stock in the rolling stand with a substantially constant Train enters, there is an even greater latitude and Height constancy of the rod-shaped rolling stock.

To keep the train constant, it is provided that the rolling stock the rolling mill is subjected to a train control. The train regulation can be designed in particular as a minimum traction control.

The train control can z. B. be realized that the Walzgut before the rolling stand is subjected to a loop control.

According to the invention it is provided that the difference between the actual rolling gap and the target roll gap by the roll engagement correction value is compensated to a part. Because this way Cross-sectional fluctuations of the incoming rolling uniform on the actual height and the actual width of the expiring rolling stock distributed. Preferably, the part is rolling force and / or frequency dependent.

• die Arbeitswalzen des Walzgerüsts mit einer Betriebsdrehzahl rotieren,
• die Ist-Walzkraft gemäß dem Abtast-Theorem mindestens zweimal pro Umdrehung der Arbeitswalzen des Walzgerüsts erfaßt wird,
• der Walzenanstellungs-Korrekturwert dem Walzgerüst als Summe von Frequenzkomponenten zugeführt wird,
• die mit der Betriebsdrehzahl korrespondierende Frequenzkomponente dem Walzgerüst nach einer Filterzeit zugeführt wird und
• die Arbeitswalzen des Walzgerüsts während der Summe von Gerüstregelzeit und Filterzeit in etwa ein ungeradzahliges Vielfaches einer halben Umdrehung zurücklegen.

The regular effort is minimized if

• rotate the work rolls of the rolling stand at an operating speed,
• the actual rolling force is detected according to the sampling theorem at least twice per revolution of the work rolls of the rolling stand,
• the roll pitch correction value is supplied to the rolling mill as a sum of frequency components,
• the frequency component corresponding to the operating speed is supplied to the rolling stand after a filtering time, and
• the work rolls of the roll stand during the sum of skeleton rule time and filter time in about an odd multiple of half a turn.

Rod-shaped rolling stock is rolled in many-stand rolling mills. The invention therefore more particularly relates to a rolling process, in which a rod-shaped rolling stock, in particular bar or wire, first passes through a front and then a rear rolling stand, wherein both the front and the rear roll stand with a the rolling process described above are operated and wherein the Anstellrichtungen the work rolls of the rolling stands vertically stand on each other.

• daß die Ist-Höhe und die Ist-Breite des Walzguts an einer Erfassungsstelle hinter dem hinteren Walzgerüst erfaßt werden und
• daß aus der Ist-Höhe und der Ist-Breite aus einem Walzplan die Soll-Walzspalte für die Walzgerüste derart bestimmt werden, daß die Differenz zwischen der Ist-Höhe und einer Soll-Höhe und die Differenz zwischen der Ist-Breite und einer Soll-Breite gegen Null gehen.

The rolling process can thereby be further improved

• that the actual height and the actual width of the rolling stock are detected at a detection point behind the rear rolling stand, and
• that from the actual height and the actual width from a rolling plan, the nominal roll gaps for the rolling stands are determined such that the difference between the actual height and a desired height and the difference between the actual width and a nominal Wide go to zero.

Preferably, the actual height and the actual width should be simultaneous be detected.

The rolling process works even more precisely when the nominal roll gap fed to the rolling stands by a waiting time, where the waiting time is determined by the quotient between an the rolling stock length located at the rear and at the front roll stand and the rolling speed of the front rolling mill is determined.

The control dynamics of the above rolling process is characterized by between the front rolling stand and the detection point for the actual height and the actual width of the rolling stock located Walzgutlänge limited. The control dynamics can therefore be improved by that for the rear roll stand determines an additional target roll gap such is that the ratio of relative errors in height and the Width remains as constant as possible, with the relative error in the Height by the difference between the actual height and the target height, divided by the desired height, and the relative error in the width by the Difference between actual width and nominal width divided by the nominal width, given is.

When determining the nominal roll gap for the rolling stands must while of course the influence of the additional target roll gap on the actual height and the actual width of the rolling stock are taken into account.

As long as the rolling stock has not yet passed through the registration point, the control loop for determining the nominal roll gap is not closed. Preferably, therefore, during rolling of rolling stock from the actual height, the target height, the actual width and the target width Preliminary positions for the rolling stands. With these appointments as control values, a subsequent rolling stock can then be rolled until the tip of the subsequent rolling stock the detection point goes through and so closes the loop. The rolling stands can still with the pre-employment after the closing of the control loop be applied as pre-tax values.

The dynamics and also the control accuracy of the rolling stands is in Full scope only given if the roller adjustments of Rolling scaffolding within a given range of employment move. Preferably, therefore, from the Walzenanstellungen the Rolling stands for at least one upstream of the front rolling stand Roll stand determined a target roll gap. This can be guaranteed be that the roll settings of the two rolling stands move within the most favorable employment range.

Figur 1

einen Teil einer mehrgerüstigen Drahtwalzstraße,

Figur 2

ein Vertikalgerüst,

Figur 3

ein Kraft-Walzspaltdiagramm und

Figur 4

ein Horizontalgerüst.

Further advantages and details emerge from the following description of an embodiment. Here are a schematic diagram:

FIG. 1

a part of a multi-stand wire rod mill,

FIG. 2

a vertical framework,

FIG. 3

a force roll gap diagram and

FIG. 4

a horizontal frame.

A rolling mill for rod-shaped rolling stock, z. As bar or wire, usually consists of a variety of rolling stands. In Fig. 1, four of these rolling stands are shown and provided with the reference numerals 1-4. A rod-shaped rolling stock 5, according to embodiment material 5 for wire, steel passes in a transport direction z successively first the rolling stand 4, then the rolling stand 3, then the rolling stand 2 and finally the roll stand 1. Behind the rolling stand 1 is at a detection point 6 a Thickness meter 7 arranged. Between the rolling stand 1 and the detection point 6 and the rolling stand 2 are rolling stock l ₀ , l _{1 of} the rolling stock. 5

The rolling stands 1 and 3 are vertical scaffolding. Theirs are theirs two work rolls 8 arranged vertically. The work rolls 8 are thus adjustable relative to each other in a Anstellrichtung x. The Setting direction x is horizontal. The rolling stands 2 and 4 however, are horizontal scaffolding. With them are their two work rolls 8 in a Anstellrichtung y adjustable, which vertically runs.

The Anstellrichtungen x, y form together with the transport direction z of the rolling stock 5 a right-handed, rectangular coordinate system (x, y, z).

The 5 runs rolling in the roll stand 4 at a rolling speed v _4, wherein in the y direction has a before rolling in the roll stand 4 has a dimension x ₄ in x-direction and y. ₄

The rolling stock 5 is rolled in the rolling stand 4, wherein the work rolls 8 of the rolling stand ₄ rotate at an operating speed n ₄ . After rolling, the rolling stock 5 runs out of the roll stand 4 at a rolling speed v ₃ . At this time, the rolling stock 5 dimensions x ₃ and y ₃ in the x-direction or y-direction. With these values, it enters the mill stand 3.

In an analogous manner, the rolling stock between the rolling stands 3 and 2 has a rolling speed v ₂ and dimensions x ₂ , y ₂ in the x-direction or y-direction. Likewise, the rolling stock 5 between the rolling stands 2 and 1 has a rolling speed v ₁ and dimensions x ₁ , y ₁ . From the rolling stand 1, the rolling stock then runs at a rolling speed v ₀ and dimensions x ₀ , y ₀ .

As already mentioned, the rolling stands 2 and 4 are horizontal scaffolding. In them, the dimension y ₁ , y _{3 of} the expiring rolling stock 5 in the y-direction thus corresponds to the actual height. The dimension x ₁ , x _{3 of} the expiring rolling stock 5 corresponds to the actual width. In the rolling stands 1 and 3, this is reversed. Here, the dimension x ₀ , x ₂ corresponds to the actual height behind the respective rolling stand 1 or 3, the dimension y ₀ , y _{2 of} the actual width.

Each two work rolls 8 of the rolling stands 1-4 each form a rolling caliber with an actual rolling gap s ₁ to s _4th The actual roll gaps s ₁ to s ₄ can be adjusted to a corresponding desired roll gap s ₁ * -s ₄ * by a corresponding adjustment a ₁ to a _{4 of} the respective rolling stand 1-4. The work rolls 8 of the rolling stands 1 and 2 are about hydraulic cylinder units 12 relative to each other employable. The rolling stands 3 and 4 can also be adjusted via hydraulic cylinder units. Alternatively, it is also possible in the rolling stands 3 and 4 to employ these via an electric or hydraulic motor with downstream gear.

If the beginning of the rolling stock 5 enters the rolling stands 1-4, no actual values of the rolling stock 5 can be detected in the detection point 6 yet. The rolling mills 1-4 are therefore initially operated in controlled operation with predetermined rolling gaps s ₁ * -s ₄ *. As soon as the beginning of the rolling stock 5 passes through the detection point 6, the actual height h ₀ = x ₀ and the actual width b ₀ = y _{0 of} the rolling stock 5 are detected simultaneously via the thickness measuring device 7. The values h _0, b ₀ are reported to a rolling plan computer 9, which determines therefrom on the basis of a rolling schedule the set rolling nip s ₁ *, s ₂ * for the rolling stands 1 and 2. Of course, the calculation of the setpoint values s ₁ *, s ₂ * takes into account the coupling of length, height and width changes in the roll stands 1 and 2. The setpoints s ₁ *, s ₂ * are determined such that the difference between the actual Height h ₀ and a desired height h ₀ * and the difference between the actual width b ₀ and a desired width b ₀ * go to zero.

Between the rolling stands 1 and 2 is the Walzgutlänge l _1st A location of the rolling stock 5, which is rolled at any time from the rolling stand 2, thus requires a running time t = l ₁ : v ₁ to get to the rolling stand 1. Thus, the desired roll gaps detected s ₁ * and s * applied to the same point of the rolling material 5 _2, have the nominal roll gaps s ₁ *, s * are the rolling stands 1, 2 thus fed offset in time by a wait time _2, the same the term is t. The target rolling gap s ₂ * is therefore fed to the rolling stand 2 by the transit time t than the desired rolling gap s ₁ * of the rolling stand 1.

The rolling stock 5 is rolled in the rolling stands 1-4 with actual rolling forces F ₁ to F ₄ . Due to the actual rolling forces F ₁ to F _4, the actual rolling gaps s ₁ - s _{4 of} the rolling stands 1-4 spring up. The actual roll gaps s ₁ to s ₄ thus obtained as the sum of an adjustment a ₄ to a ₁ of the respective roll stand 1-4 and the respective Gerüstauffederung C ₁ F ₁ to F ₄ C. ₄ C ₁ to C ₄ are the spring constants of the rolling stands 1-4.

In order to keep the actual roll gap s _{1 of} the roll stand 1 at its desired roll gap s ₁ *, the actual rolling force F _{1 is} detected according to FIG. 2 and supplied to a frequency filter 10. The frequency filter 10 filters the rolling force F ₁ and passes the filtered value further to a frame controller. 11 The frame controller 11 determines in accordance with FIG. 3 on the basis of the filtered actual roll force F ₁ a rolling force caused Walzspaltauffederung .DELTA.S _1. Based on these rolling force caused Walzspaltauffederung .DELTA.S ₁ and the desired roll gap s ₁ * determines the frame controller 11 then a roll adjustment correction value .DELTA.a ₁ for the roll adjustment a _1, so that the actual roll gap s ₁ the desired roll gap s ₁ * is approached. The frame controller 11 outputs the sum of the previous target adjustment a ₁ * and roll adjustment correction value .DELTA.a ₁ as a new target adjustment a ₁ 'then of hydraulic cylinder units 12 made, by means of which the roll adjustment is a ₁ changed by the roll adjustment correction value .DELTA.a. ₁ The change in the roller position a ₁ takes place within a frame control time T of about 30 ms. After the scaffold control time T, the actual rolling gap s ₁ is then set again to the desired rolling gap s ₁ *, so that the rolling stock 5 again runs out of the rolling stand 1 with the desired height h ₀ * and the desired width b *.

Height h ₀ and width b _{0 of} the rolling stock 5 depend not only on the rolling force F ₁ and the setting a _{1 of} the roll stand 1, but also on the train with which the rolling stock 5 in the roll stand 1 on or from the rolling stand 1 expires. In order to rule out train fluctuations, which would result in height and width variations, the rolling stock 5 is subjected to tension control in front of the rolling stand 1. The tension control is preferably designed as a minimum tension control. It can be realized for example by means of a loop control. By means of the tension control is achieved that the rolling stock 5 enters the rolling mill 1 with a substantially constant train.

The maximum permissible tension fluctuations are 5 MPa. Even better is when the pull fluctuations are limited to 2 MPa.

With the method described above, with a full penetration of the roll gap control, the actual roll gap s _{1 can} always be maintained at its desired roll gap s ₁ *. The rolling force F ₁ but is also dependent on the temperature and the cross section of the incoming rolling stock. If the frame controller 11 would always control the actual roll gap s ₁ to its desired roll gap s ₁ *, the actual height h ₀ would always be equal to the setpoint height h ₀ *. The actual width b ₀ would vary greatly. It is therefore generally more favorable if the difference between the actual rolling gap s ₁ and the target rolling gap s ₁ * is only partially compensated by the frame regulator 11 by means of the roll adjustment correction value δa ₁ . The part is usually between 20 and 90 percent of the full correction. In particular, it can be roller force and frequency dependent. With such a correction is only partial the roll error uniform h to both dimensions _0, b ₀ distributed.

The rolling speed v ₄ to v ₀ increases steadily from the roll stand 4 to the roll stand 1. By contrast, the diameters of the work rolls 8 either remain the same or decrease from the rolling stand 4 to the rolling stand 1. As a result, the work rolls 8 of the rolling stand 1 rotate fastest. Due to any eccentricities of the work rolls 8 caused periodic errors can therefore have a maximum frequency corresponding to the rotational speed n _{1 of} the roll stand 1. According to the sampling theorem, therefore, the actual rolling force F _{1 of} the rolling stand 1 is detected at least twice per revolution of the work rolls 8 of the rolling stand 1. The roller adjustment correction value δa ₁ is frequency-filtered according to the known frequencies corresponding to the speeds n ₁ to n ₄ in the frame controller 11. Only the frequency-filtered roll adjustment correction value δa ₁ is then fed to the rolling stand 1.

The stabilization of eccentricity is particularly effective when the roll adjustment correction value .DELTA.a ₁ is fed to the roll stand 1 as the sum of frequency components. The frequency component corresponding to the operating speed n ₁ of the roll stand 1 is fed to the roll stand 1 after a filter time T '. This frequency component may optionally be weighted with its own gain factor between 0.15 and 10.0 relative to the other frequency components. The filter time T 'is selected such that the work rolls 8 of the roll stand 1 during the sum of skeleton rule time T and filter time T' between 0.4 and 0.55 revolutions, ie in about half a turn, possibly plus any number of complete revolutions , return.

The roll stand 2 is controlled in the same manner as shown in FIG like the roll stand 1.

Between the rolling stands 1 and 2 is the Walzgutlänge l _1st Between the rolling stand 1 and the detection point 6 is the Walzgutlänge l ₀ . The dynamics of the monitor control is thus limited by the sum of l ₁ : v ₁ + l ₀ : v ₀ . Faster disturbances can not be compensated by means of the method described above.

If, however, only the rolling stand 1 were regulated, the maximum control dynamics of the monitor control would be given by l ₀ : v ₀ . The control dynamics would be higher. This can be exploited by determining an additional nominal roll gap δs * for the roll stand 1. This value is determined such that the ratio of the relative errors δh, δb in the height and the width of the rolling stock 5 remains as constant as possible, in any case within a preselectable barrier. The relative error δh in the height is given by the difference between the actual height h ₀ and the target height h ₀ * divided by the desired height h ₀ *. The relative error δb in the width is given in an analogous way by the difference between the actual width b ₀ and the desired width b ₀ * divided by the desired width b ₀ *. The influence of the additional desired roll gap .DELTA.S ₁ * to the actual height h _0, and the actual width of b ₀ must, s are ₂ * taken into account for the rolling stands 1 and 2 in the determination of the desired roll gaps s ₁ *, of course.

The method described above for adjusting the desired roll gaps s ₁ *, s ₂ * can of course only be carried out when the beginning of the rolling material 5 has already reached the detection point 6, and happens, the monitor control is thus closed. Before this time, the control loop is open. The rolling stands 1, 2 must therefore be operated during this period in controlled operation. Measurements of the actual height h ₀ , the actual width b ₀ and the corresponding desired values h ₀ *, b ₀ *, however, can be used to determine the set roll gap s ₁ *, s ₂ * based on a rolling model in the rolling plan computer 9 to which the desired actual values h ₀ , b _{0 are} to be expected. With these values for the nominal roll gaps s ₁ *, s ₂ *, the rolling stands 1, 2 are then operated as long as the control loop of the monitor control is open.

The rolling stands 1, 2 are optimally operable only within a predetermined range of employment. In order to always ensure that the actual jobs a ₁ , a _{2 of} the rolling stands 1, 2 move within this range, the actual jobs a ₁ , a _{2 of} the rolling stands 1, 2 are transmitted to the rolling plan computer 9. As soon as the actual positions a ₁ , a ₂ reach the limits of their permissible ranges, the nominal roll gaps s ₃ *, s ₄ * of the rolling stands 3, 4 are changed such that the actual positions a _1, a _{2 of} the rolling stands 1, 2 are again shifted more in the middle of their allowable dynamic range. Thus, from the roll positions a ₁ , a _{2 of} the roll stands 1, 2 for the upstream roll stands 3, 4 new set roll gaps s ₃ *, s ₄ * are determined.

With the rolling process according to the invention can be for wire and Bar steel lines achieve unprecedented accuracy. Especially can the ovality of the rolling stock 5 at the exit of the rolling train reduced to one quarter of the value permitted by ASTM-A29 become.

LIST OF REFERENCE NUMBERS

1-4

rolling mills

5

rolling

6

registration office

7

Thickness Gauge

8th

strippers

9

Rolling plan calculator

10

frequency filter

11

scaffolding regulator

12

Hydraulic cylinder units

a ₁ -a ₄

Actual employment

a ₁ * -a ₄ *, a ₁ '

Target employment

b ₀ , b ₀ *

spread

C ₁ -C ₄

spring rates

F ₁ -F ₄

rolling forces

h _0, h ₀ *

heights

l ₀ , l ₁

Walzgutlängen

n ₁ -n ₄

speeds

s ₁ -s ₄

Actual nips

s ₁ * -s ₄ *

Target nips

t, T, T '

times

v ₀ -v ₄

rolling speeds
x ₀ -x ₄ ,

y ₀ -y ₄

Dimensions

x, y

Anstellrichtungen

z

transport direction

δa ₁

Roll adjustment correction value

.DELTA.B, .delta.h

relative error

.DELTA.S ₁

Walzspaltauffederung

.DELTA.S ₁ *

Additional target nip

Claims (15)

1. A method for rolling rod-shaped rolling stock (5), in particular steel rods or wire (5), in a roll stand (1) with two working rolls (8) that can be adjusted relative to one another in an adjusting direction (x) by means of a hydraulic cylinder unit (12) and together form a roll pass with an actual roll gap (s₁) such that the rolling stock (5) emerges from the roll stand (1) with an actual height (h₀) and an actual width (b₀), as well as with a rolling speed (v₀),

   wherein the rolling stock (5) is rolled with an actual rolling force (F₁),

   wherein the actual rolling force (F₁) is measured,

   wherein a roll gap deflection (s₁) that is conditional upon the rolling force is determined based on the actual rolling force (F₁),

   wherein a roll adjustment correction value (a₁) is determined based on the roll gap deflection (s₁) that is conditional upon the rolling force and a nominal roll gap (s₁*), namely such the actual roll gap (s₁) is approximated to the nominal roll gap (s₁*), and

   wherein a roll adjustment (a₁) is changed by the roll adjustment correction value ( a₁) within a stand control time (T).
2. The rolling method according to Claim 1, characterized in that the rolling stock (5) is introduced into the roll stand (1) with an essentially constant tension.
3. The rolling method according to Claim 2, characterized in that the tension of the rolling stock (5) is regulated upstream of the roll stand (1).
4. The rolling method according to Claim 3, characterized in that the tension is regulated in the sense of a minimum tension control.
5. The rolling method according to Claim 3 or 4, characterized in that the looping of the rolling stock (5) is regulated upstream of the roll stand (1).
6. The rolling method according to one of the preceding claims, characterized in that the difference between the actual roll gap (s₁) and the nominal roll gap (s₁*) is in part compensated by the roll adjustment correction value (a₁).
7. The rolling method according to Claim 6, characterized in that the part is dependent on the rolling force and/or the frequency.
8. The rolling method according to one of the preceding claims, characterized in

   that the working rolls (8) of the roll stand (1) rotate with an operating speed (n₁), in

   that the actual rolling force (F₁) is measured at least twice per revolution of the working rolls (8) of the roll stand (1), in

   that the roll adjustment correction value (a₁) is fed to the roll stand (1) in the form of the sum of frequency components, in

   that the frequency component which corresponds to the operating speed (n₁) is fed to the roll stand (1) after a filter time (T), and in

   that the working rolls (8) of the roll stand (1) are approximately turned by an uneven multiple of one-half revolution during the sum of the stand control time (T) and the filter time (T').
9. A rolling method, in which rod-shaped rolling stock (5), in particular steel rods or wire (5), initially passes through a front roll stand and subsequently through a rear roll stand (2, 1), characterized in that the front roll stand as well as the rear roll stand (2, 1) are operated such that a rolling method according to one of the preceding claims is realized, and in that the adjusting directions (y, x) of the working rolls (8) of the roll stands (2, 1) lie perpendicular to one another.
10. The rolling method according to Claim 9, characterized in

    that the actual height (h₀) and the actual width (b₀) of the rolling stock (5) are measured at a measuring point (6) downstream of the rear roll stand (1), and in

    that the nominal roll gaps s₁*, (s₂*) for the roll stands (1, 2) are obtained from a rolling plan based on the actual height (h₀) and the actual width (b₀), namely such that the difference between the actual height (h₀) and a nominal height (h₀*) and the difference between the actual width (b₀) and a nominal width (b₀*) are compensated.
11. The rolling method according to Claim 10, characterized in that the actual height (h₀) and the actual width (b₀) are measured simultaneously.
12. The rolling method according to Claim 10 or 11, characterized in that the nominal roll gaps (s₁*, s₂*) are fed to the roll stands (1, 2) with a time delay (t), wherein the time delay (t) is defined by the quotient between a rolling stock length (l₁) situated between the rear roll stand and the front roll stand (2, 1) and the rolling speed (v₁) of the front roll stand (2).
13. The rolling method according to Claim 12, characterized in that an auxiliary nominal roll gap (s₁*) is determined for the rear roll stand (1), namely such that the ratio between the relative deviations ( h, b) in height and width remains as constant as possible, wherein the relative deviation ( h) in height is defined by the difference between the actual height (h₀) and the nominal height (h₀*) divided by the nominal height (h₀*), and wherein the relative deviation ( b) in width is defined by the difference between the actual width (b₀) and the nominal width (b₀*) divided by the nominal width (b₀*).
14. The rolling method according to one of Claims 10 - 13, characterized in that nominal roll gaps (s₁*, s₂*) for the roll stands (1, 2) are determined during the controlled operation based on the actual height (h₀), the nominal height (h₀*), the actual width (b₀) and the nominal width (b₀*).
15. The rolling method according to one of Claims 10 - 14, characterized in that a nominal roll gap (s₃*, s₄*) for at least one roll stand (3, 4) arranged upstream of the front roll stand (2) is determined based on the roll adjustments (a₁, a₂) of the roll stands (1, 2).

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