WO2000038853A1

WO2000038853A1 - Method and device for rolling a metal strip

Info

Publication number: WO2000038853A1
Application number: PCT/DE1999/004080
Authority: WO
Inventors: Thomas Peuker
Original assignee: Siemens Aktiengesellschaft
Priority date: 1998-12-28
Filing date: 1999-12-22
Publication date: 2000-07-06
Also published as: DE19860491A1

Abstract

The invention relates to a method and to a device for rolling a metal strip, especially a steel strip, by means of a rolling mill which comprises at least one rolling stand. According to the inventive method, the speed of the rolling stand is adjusted in such a manner that the throughput of the metal strip through the rolling mill is maximized or at least increased. According to the inventive method, it is made sure that in a rolling mill which is provided with at least two rolling stands the power required for rolling the metal strip is distributed on the rolling stands.

Description

description

Method and device for rolling metal strip

The invention relates to a method for rolling metal strip, in particular a steel strip, by means of a rolling train with at least one roll stand. In addition, the invention also relates to an associated device, i.e. a rolling mill with at least one rolling stand or alternatively a rolling mill with at least two rolling stands.

From the publication "DOMA auf fiz technik ^λ , Frankfurt am Main AN50021 (US Report 1973, Report No. CE / B / 25/72), an operational analysis and an optimization of the rolling process, especially of flat iron as a metal strip, are known, from which one can Relationship between the maximum throughput of steel slabs and the final dimensions of the flat iron plates produced therefrom. In particular, a relationship between throughput and compliance with the dimension of the rolled product is specified there, the throughput becoming lower the more precisely the rolling is carried out. This is unsatisfactory for the practice of rolling metal strip. Suitable rolling programs must be determined to ensure that the final dimensions are maintained.

With certain rolling programs, i.e. certain pass schedules, there is also a limitation in the throughput of the rolling mill in the rolling mills, for example due to the thermal load capacity of the drives of the individual rolling stands. In absolute terms, small increases in throughput can bring about a considerable cost advantage.

Starting from the state of the art, it is the object of the invention to specify methods which determine the throughput of a rolling mill increase or optimize, and create associated facilities.

This object is achieved according to the invention in a method of the type mentioned at the beginning by the measures of claim 1 or 2 or in a device of the type mentioned at the beginning by the features of claim 6 or 7. Further developments of the invention are specified in the respective dependent claims.

In the invention, for rolling metal strip, in particular a steel strip, by means of a rolling train with at least one rolling stand, the speed of the rolling stand, in particular as a function of the material throughput, is set through the rolling train in such a way that the throughput of the metal strip through the rolling train is maximized or at least is increased. In this way, an increase in the throughput of the rolled metal strip through a rolling mill can be achieved, which is associated with a considerable absolute cost advantage.

In an alternative according to the invention, for rolling metal strip, in particular a steel strip, by means of a rolling train with at least two rolling stands, the power required for rolling the metal strip is distributed through the rolling train to the at least two rolling stands, in particular depending on the material throughput, that the throughput of metal strip through the rolling mill is maximized or at least increased. In this way, the throughput of the rolled metal strip can be increased by a

Rolling mill achieve, which is associated with a considerable absolute cost advantage. In particular, provision is made to influence the performance at a given speed by changing the degree of reduction of an individual roll stand. In this way, a simultaneous _O ptimierung of power redistribution and optimization of Ge ^¬ speed particularly well achieved.

In the corresponding inventive devices is sawn Sonders advantageous if sondere for rolling metal strip, in particular ^¬ a steel strip, by means of a rolling train with at ^¬ least two rolling stands, the adjustment of the speed of the roll stands, while the distribution of the Lei ^¬ stung on the roll stands is done in such a way that the throughput of metal strip through the rolling train is maximized or at least increased. In particular, provision is made to influence the performance at a given speed by changing the degree of reduction of an individual roll stand. In this way, simultaneous optimization of power redistribution and optimization of the speed can be achieved particularly well. The increase in throughput can be significantly increased especially by combining power redistribution, in particular redistribution of the degrees of reduction or an equivalent size, and speed. This applies all the more if an online redistribution of performance to the individual roll stands is planned.

In an advantageous embodiment of the invention, the roll stands have electric drives, at least one electric drive of at least one roll stand being operated below its nominal power. Here, e.g. Drives according to DE 196 47 637 AI are used. Advantageously, the electric drives of several, in particular all, rolling stands of the rolling mill are operated below their nominal power, the drives being designed in accordance with DE 196 47 637 A1.

Further advantages and details result from the exemplary embodiments described in the figures. Show in detail 1 shows a four-stand rolling mill using the invention as an example,

2 shows a throughput optimizer with a distribution optimizer and a speed optimizer and

3 shows the structure of a heating model used in FIG. 2.

1 shows a rolling mill 1 for rolling metal strip 7. The rolling mill 1 has four roll stands 2, 3, 4, 5. The degrees of reduction .psi.i with i = 1, 2, 3, 4 and the Geschwindigkei ^¬ th Vi, where i = 1, 2, 3, 4 and the speeds of the individual roll stands 2, 3, 4, 5 by means of a so-called throughput Opti ierers 6 determined.

Such a throughput optimizer 6 is shown in more detail in FIG. The throughput optimizer 6 has a heating model 10, a distribution optimizer 11, a speed optimizer 12 and a degree of reduction calculator 13. The heating model 10 calculates the throughput m through the rolling train as a function of the length Li of the rolled metal strip 7 emerging from the i-th roll stand and the speed v _{± of} the i-th roll stand.

The distribution optimizer 11 determines from the length L _{± of} the rolled metal strip 7 when it leaves the i-th roll stand in the last optimization cycle and the throughput m and a new value for the length _{λ of} the rolled metal strip 7 when it leaves the i-th roll stand.

The speed optimizer determines depending on the

Throughput, the length L _{± of} the rolled metal strip 7 a new value for the speed v _{± of} the i-th roll stand. The loop formed by the heating model 10 and the distribution optimizer 11 and the loop formed by the heating model 10 and the speed optimizer 12 are iteratively run through until the

Throughput m is maximum.

The reduction degree calculator 13 determines, among other things. from the length Li of the rolled metal strip 7 as it emerges from the i-th roll stand, the degree of reduction φi of the roll stand.

Alternatively, it can be provided that the degree of reduction φι is calculated directly, ie that Li is replaced by _± . In this case, the heating model 10, the distribution optimizer 11 and the speed optimizer 12 must be adapted accordingly.

The throughput optimizer 6 shown in FIG 2 is a ^¬ Sonders be advantageous embodiment for a throughput, automatic ^¬ zoptimierer as both a distribution optimizer 11 and a speed optimizer provided 12th Alternatively, provision can be made to provide a throughput optimizer either without a distribution optimizer or without a speed optimizer. However, the simultaneous use of a distribution optimizer 11 and a speed optimizer 12 leads to particularly favorable results with regard to the throughput m. However it is

particularly favorable in practice, the throughput m of the metal strip 7 through the rolling mill 1 equally with the distribution optimizer 11 and the speed optimizer 12, i.e. parallel to optimize.

3 shows an exemplary embodiment of a heating model 10. The following abbreviations apply in the following: P _m mean power consumption of a drive during the rolling process

P _N nominal power of a drive of a roll stand

2,3,4,5 t duration of the rolling of the metal strip 7 t _P duration of the pause between the threading out of a metal strip 7 to be rolled and the threading of the

Head of a subsequent rolled metal band

7s m mass of a rolled metal strip 7s m throughput

M rolling torque

M _m mean rolling moment

R radius of the work rolls Vi speed of a rolled metal strip 7s at

Run-out from the i-th roll stand Li Length of a rolled metal strip 7s of a rolled-up metal strip 7s when leaving the i-th roll stand kapa leading (assumed to be 0.05 for simplification)

The heating model 10 has a rolling time calculator 20, a rolling break time calculator 21 and a throughput calculator 22. In an exemplary embodiment, the rolling time calculator 20 calculates the rolling time t _w according to equation (1):

t _w = v • (1 + kapa) (i:

In an exemplary embodiment, the roll break time calculator 21 calculates the minimum break time t _P between two rolling passes according to equation (2):

the minimum pause time t _P between two rolling passes being zero if the average power consumption P _{m of} a drive during rolling is less than its nominal power P _N. In an exemplary embodiment, the average power consumption P _{m of} a drive during rolling is calculated, inter alia, from the length _lf from which the _degree of reduction Ci can be derived, of the rolled metal strip 7 when it emerges from the i-th roll stand.

In an alternative embodiment, the roll break time calculator 21 receives the average power consumption P _{m of} a drive during rolling as an input variable. The roll break time calculator 21 also receives the nominal power P _{N of} the drive as an input variable, which is not shown in FIG. 3 for reasons of clarity.

The throughput calculator 22 calculates the throughput m according to equation (3):

m m =

For reasons of clarity, not all input and output variables of the function blocks 6, 10, 11, 12, 13, 20, 21, 22 are shown in FIGS. 1 to 3, but only those that are necessary for understanding their interaction.

Claims

claims

1. Method for rolling metal strip, in particular one

Steel strip, by means of a rolling mill with at least one

Roll stand, so that the speed of the roll stand is adjusted in such a way that the throughput of metal strip through the rolling train is maximized or at least increased.

2. Method for rolling metal strip, in particular a steel strip, by means of a rolling train with at least two roll stands, characterized in that the power which is necessary for rolling the metal strip is distributed over the at least two roll stands in such a way that the throughput of metal strip through the Rolling mill is maximized or at least increased.

3. The method according to claim 2, so that the speeds of the at least two roll stands are adjusted as a function of the throughput of metal strip through the rolling mill in such a way that the throughput of metal strip through the rolling mill is maximized or at least increased.

4. The method according to claim 1, 2 or 3 wherein the roll stands have electrical drives, so that the electrical drive of at least one roll stand is operated below its nominal power.

5. The method according to claim 4, characterized in that the electrical drives of the at least two roll stands are operated below their nominal power.

6. Rolling mill with at least one rolling stand for rolling metal strip, in particular a steel strip, according to a ^method according to one of claims 1 or 3 to 5, characterized in that the rolling mill has a speed optimizer (12) for adjusting the speed of the at least one NEN mill stand (2-5) is assigned that the throughput of metal strip (7) through the rolling mill (1) is maximized or at least increased.

7. Rolling mill with at least two roll stands for rolling metal strip, in particular a steel strip, according to a method according to any one of claims 2 to 5, characterized in that the rolling mill has a distribution optimizer (11) for such distribution of the necessary for rolling the metal strip (7). performance, to which at least two roll stands (2-5) are assigned, that the throughput of metal strip (7) through the rolling train (1) is maximized or at least increased.

8. Rolling mill according to claim 6 and claim 7, d a d u r c h g e k e n n z e i c h n e t that speed optimizer

(12) and distribution optimizer (11) together form a throughput optimizer (6).

9. Rolling mill according to claim 6 or claim 7, d a d u r c h g e k e n n z e i c h n e t that the speed optimizer (12) and / or the distribution optimizer (11) is assigned a degree of reduction calculator (13).

10. Rolling mill according to claim 6 or claim 7, characterized in that the speed opti- Mierer (12) and / or the distribution optimizer (11) is assigned a heating model (10).

11. Rolling mill according to claim 10, d a d u r c h g e k e n n z e i c h n e t that the heating model (10) has a rolling time calculator (20).

12. Rolling mill according to claim 10, d a d u r c h g e k e n n z e i c h n e t, the heating model (10) has a roll break time calculator (21).

13. Rolling mill according to claim 10, d a d u r c h g e k e n n z e i c h n e t, the heating model (10) has a throughput calculator (20).