JP7302104B2 - Method, control system and production line for controlling flatness of strip of rolled material - Google Patents

Description

The present disclosure relates generally to flatness control of strips of rolled material. In particular, a method for controlling the flatness of a strip of rolled material in a production line, a control system for controlling the flatness of a strip of rolled material in a production line, and a production line comprising the control system are provided.

A production line for rolled material typically includes several different process steps, e.g. melting furnace, hot rolling mill, cold rolling mill, furnace, annealer, stretch leveler, slitter, coiler, and uncoiler. Important parameters of such manufacturing lines are the yield of the final process steps and the resources required (overall process efficiency). The flatness of the rolled material is also an important parameter that directly affects the process yield in the final process steps. It is common today in the rolling mill industry to operate different process steps in isolation.

EP 1110635 B1 discloses a method for controlling the flatness of a strip of rolled material and a system using the method. The measured flatness of the strip being rolled is compared to both the first flatness target and the second flatness target. Flatness targets and measured flatness errors for each of one or more subsequent processes provide control signals for the mill stands to control and adjust flatness for subsequent production of rolled material of the same specification. (regulate) is used to match.

JP S6020088 B2 discloses a plate rolling processing facility comprising a hot strip mill, a tandem cold mill and a flatness meter. A flatness meter is provided on the exit side of the tandem cold mill. The installation further comprises a flatness calculator for calculating flatness by dividing the length of the Lamb wave by the amplitude of the Lamb wave. The installation further comprises a flatness controller for calculating a work roll crown. This facility further comprises a crown correction device for calculating optimum values in terms of strip threadability and coil winding shape based on the work roll crown. The assembly further includes a crown controller for calculating a roll bending force correction value based on the difference from the desired crown value output from the adder.

In strip flatness control of rolled material, the key factors that determine how well flatness errors can be eliminated are the mechanical actuators of the cold rolling mill and the thickness profile of the incoming material. . The thickness profile of the strip is produced on the hot rolling mill and cannot be substantially altered on the cold rolling mill without causing flatness defects. If the mechanical actuators do not allow the roll nip of each cold mill to conform to the thickness profile of the entry material, flatness errors will likely exist in the strip. Therefore, when a strip with a particular thickness profile is run through a cold rolling mill with a particular roll gap, the difference between the thickness profile and the roll gap causes flatness errors in the strip. Additionally, if there are multiple cold rolling mills with different types of roll gaps, this can also cause flatness errors.

Furthermore, if the roll gap of the cold mill is controlled according to the method described in EP 1110635 B1, there is a risk that the required flatness target is outside the permissible operating conditions of the cold mill. In other words, very large corrections may be required by the cold mill flatness target to achieve the desired flatness downstream. Therefore, in some cases either the required flatness compensation cannot be achieved by the cold rolling mill or there is a possible risk of causing strip breakage.

One object of the present disclosure is to provide a method of controlling the flatness of a strip of rolled material that allows for reduced flatness errors.

It is a further object of the present disclosure to provide a method of controlling the flatness of a strip of rolled material that allows for reduced flatness errors in the strip downstream of the cold rolling mill.

It is a still further object of the present disclosure to provide a method of controlling the flatness of a strip of rolled material that allows for reduced flatness errors in the strip downstream of subsequent processes on the cold rolling mill. is.

A still further object of the present disclosure is to provide a method of controlling the flatness of a strip of rolled material that reduces the risk of strip breakage.

A still further object of the present disclosure is to provide a method of controlling the flatness of a strip of rolled material that provides improved yield.

A still further object of the present disclosure is to provide a method of controlling the flatness of a strip of rolled material that combines and solves some or all of the above objects.

A still further object of the present disclosure is to provide a control system for controlling the flatness of a strip of rolled material in a production line that solves one, some or all of the aforementioned objects. .

A still further object of the present disclosure is to provide a manufacturing line with a control system that solves one, some or all of the above objects.

According to one aspect, there is provided a method of controlling the flatness of a strip of rolled material in a production line comprising a hot rolling mill and at least one cold rolling mill downstream of the hot rolling mill, comprising: The method includes generating flatness data associated with the strip in one or more of the at least one cold rolling mills and/or after passing the strip through one or more of the at least one cold rolling mills. determining a strip thickness profile target for the hot rolling mill based on the flatness data; passing the strip through the hot rolling mill and measuring the thickness of the strip based on the thickness profile target; and adjusting the thickness.

The production line comprises a hot rolling side with one or more hot rolling mills and a cold rolling side with one or more cold rolling mills. Hot rolling is a metal working process that takes place above the recrystallization temperature of the material. Cold rolling is done with the metal below its recrystallization temperature, which increases strength through strain hardening. The rolled material can be, for example, aluminium, steel or copper.

Instead of using a thickness profile target on the hot roll side that is not necessarily optimal for the downstream cold roll side or the process downstream of the cold roll side, the method is to achieve normal or achieved Utilize thickness profile goals based on possible flatness influencing effects. In this way, downstream flatness affecting effects can be matched to the entry thickness profile of the strip, thereby reducing or eliminating flatness errors. Thickness profile targets used in hot rolling mills create the need for one or more flatness corrections downstream of the hot rolling side. By selecting thickness profile targets such that these flatness correction needs can be met by one or more cold rolling mills and/or by subsequent processes, flatness errors in the strip can be can be reduced.

In other words, by determining a strip thickness profile target for the hot rolling mill based on the flatness data, the hot rolling mill can ensure that downstream processes, such as one or more cold rolling mills, are flattened. This will produce a thickness profile of the strip that can better compensate for the thickness. Thus, the method provides feedback of flatness affecting effects from the cold rolling side of the production line or downstream of the cold rolling side to the hot rolling side. Hot rolling mills have better possibilities for adjusting the thickness profile problem, which later translates into a flatness problem. Thus, the method challenges the norm in the prior art for what is considered a good thickness profile from a hot rolling mill. Today, this standard defines a thickness profile from a hot rolling mill whose shape resembles a second order polynomial, with a 0.5% crown, e.g., 0.5% higher in the center of the strip. To have.

Each cold mill may comprise at least one mechanical actuator arranged to control one or more rolls of the cold mill. In this case, the flatness data may comprise a flatness model associated with one of the at least one mechanical actuator, where the flatness model defines the effect on the strip by the mechanical actuator. By adjusting the rolls with mechanical actuators, the roll gap of the cold rolling mill can be changed. The flatness model therefore defines the capacity of the mechanical actuator to change the flatness of the strip.

In this variation, the method utilizes one or more flatness models that can actually be achieved by one or more mechanical actuators. By determining thickness profile targets based on one or more of these flatness models, the roll gap can be matched to the entry side thickness profile of the strip to reduce or eliminate flatness errors. For example, by selecting a thickness profile target such that the need for flatness correction downstream can be met by one or more cold mill mechanical actuators, the cold mill thermal actuators can: It becomes "emancipated" and can instead be used to correct local defects in the strip.

Accordingly, the method may comprise determining, for one or more mechanical actuators, a flatness model that can be achieved by the mechanical actuators. By determining strip thickness profile targets for the hot rolling mill based on one or more flatness models, the hot rolling mill provides a thickness profile that the mechanical actuators can compensate for. In this way an increased flatness of the strip is achieved downstream of the cold rolling mill.

As used herein, the terms shape and flatness may be used interchangeably. One or more flatness models may be associated with each mechanical actuator. Each flatness model may depend on various parameters, such as the position of the associated mechanical actuator and/or the width of the strip.

Determination of thickness profile targets based on flatness data may comprise machine learning. Machine learning uses sample data such as, for example, the measured flatness of the strip downstream of one or more of the at least one cold rolling mill, flatness models for each of the one or more mechanical actuators, and/or a mathematical model based on hot mill thickness profile targets may be used.

Alternatively, thickness profile target determination can be performed using different statistical techniques, including fuzzy logic and neuro-fuzzy logic control methods.

Each hot rolling mill has one or more actuators, such as one or more mechanical actuators and/or one or more thermal actuators arranged to control one or more rolls of the hot rolling mill. can be provided. Each hot rolling mill may be configured to modify the thickness profile of the strip being rolled. The hot rolling side may be equipped with one or more thickness profile measurement devices.

Each hot rolling mill may be controlled based on a thickness profile target. Each hot rolling mill may further comprise a thickness profile controller configured to control the hot rolling mill to minimize thickness profile errors using actuators in the hot rolling mill.

Each hot rolling mill can be a single mill stand or can be a tandem mill with multiple mill stands. Alternatively or additionally, the production line may comprise a reversible hot tandem rolling mill.

Each cold rolling mill may be equipped with one or more actuators, such as one or more mechanical actuators. Each mechanical actuator may be configured to control one or more of the rolls of the cold mill. In this way the roll gap of the cold rolling mill can be adjusted. The mechanical actuators can be controlled to provide, for example, work roll bending, work roll skewing, intermediate roll bending, intermediate roll side shifting, and the like. One or more of the cold rolling mills may also be equipped with one or more thermal actuators.

Each cold rolling mill may be configured to modify the flatness profile of the strip being rolled. The cold roll side may be equipped with one or more shape gauges.

Each cold rolling mill may be controlled based on one or more flatness models. Each cold rolling mill may further comprise a flatness controller configured to control the cold rolling mill to minimize flatness errors using actuators in the cold rolling mill. Each cold mill can be a single mill stand or can be a tandem mill with multiple mill stands. Alternatively or additionally, the production line may comprise a reversing cold tandem rolling mill.

The flatness data may comprise a flatness model associated with each of the one or more of the at least one mechanical actuators for the plurality of cold rolling mills, the thickness profile target determination using the flatness model determining a strip thickness profile target for the hot rolling mill that best matches a combination of .

Accordingly, the method may comprise determining a plurality of flatness models associated with respective mechanical actuators of a plurality of cold rolling mills. Each flatness model may, for example, be represented as a polynomial over the width of the strip, where it depends on the strip width. Each flatness model for a mechanical actuator can be determined as a flatness influence of the mechanical actuator.

Each cold mill actuator, either mechanical or thermal, affects the flatness of the strip as it passes through the cold mill. The flatness model is a model of this effect on flatness due to the actuators as the strip is passed through the cold rolling mill.

The effect of each actuator on flatness may depend on the actuator settings and/or the actual rolling conditions. Actual rolling conditions may comprise, for example, thermal crown on the work rolls (depending on strip speed and possible previous passes), strip hardness, and/or total rolling force.

The method may further comprise determining a thickness profile model of the strip for the hot rolling mill, the thickness profile model defining the effects of the one or more mechanical actuators on the strip of the hot rolling mill. do. Determining the thickness profile target may comprise, for example, optimizing the hot mill thickness profile model to best match the flatness model for the mechanical actuators in the most downstream cold mill. Alternatively or additionally, determination of the thickness profile target may include thickness profile targets for a plurality of hot rolling mills to best match a flatness model of one or more mechanical actuators of at least one cold rolling mill. optimization of the height profile model. In either case, a thickness profile model that solves the optimization problem can be set as a thickness profile target. Alternatively, the flatness model can be normalized in amplitude to the desired crown and then used as the thickness profile target.

If the flatness data comprises one or more flatness models associated with one or more mechanical actuators for each of a plurality of cold rolling mills, determination of the thickness profile target is a combination of flatness models determining a strip thickness profile target for the hot rolling mill that best matches the . The flatness models of the mechanical actuators of the multiple cold mills can be combined into a combined flatness model representing the total effect on the flatness of the strip by the multiple cold mills. In this case, the thickness profile target can be determined based on the combined flatness model.

The production line may comprise a plurality of cold rolling mills, the flatness data comprising a flatness model associated with each of one or more of the at least one mechanical actuator of the most downstream cold rolling mill. be prepared. High flatness immediately downstream of the last cold mill by determining the strip thickness profile target for the hot rolling mill based on the flatness model of the mechanical actuators of the most downstream cold mill. Provides the best conditions for obtaining degrees. A thickness profile target may be determined to mirror a flatness model associated with one or more of the at least one mechanical actuator of the most downstream cold rolling mill.

The flatness model can depend on the width of the strip. That is, for a first width of the strip, one mechanical actuator may have a first flatness model, and for a second width of the strip different from the first width, this mechanical actuator The actuator may have a second flatness model that is different than the first flatness model. The flatness model can also depend on various other parameters.

The flatness data may comprise the measured flatness of the strip. The flatness data may comprise the measured flatness of the strip after undergoing subsequent processing for each of the at least one cold rolling mill. Subsequent processes can be, for example, strip winding processes, strip unwinding processes, and/or galvanizing or aluminizing processes.

In this variation, the method may take advantage of the flatness effect on the strip from one or more subsequent processes, i.e., downstream of the most downstream cold rolling mill. By determining the thickness profile target based on flatness effects from subsequent processes, the flatness effects can be matched to the entry side thickness profile of the strip to reduce or eliminate flatness errors. Furthermore, the risk of strip breakage is reduced or eliminated as flatness effects from subsequent processes are compensated on the hot rolled side rather than the cold rolled side.

Flatness data may be determined by one or more profilometers. The shape meter can be, for example, a Stressometer. The flatness data comprising the measured flatness of the strip may comprise multiple flatness measurements along the length of the strip.

A thickness profile target can be determined based on the width of the strip. That is, a thickness profile target can be determined based on the flatness data and the width of the strip.

According to a further aspect, a control system for controlling the flatness of a strip of rolled material in a production line comprising a hot rolling mill and at least one cold rolling mill downstream of the hot rolling mill. is provided, the control system comprising at least one data processing device and at least one memory in which a computer program is stored, the at least one computer program comprising program code, the program code comprising at least one when executed by one or more of the data processing devices, in one or more of the at least one data processing devices, in one or more of the at least one cold rolling mills, and/or in the at least one determining flatness data associated with the strip after passing the strip through one or more of the cold rolling mills; and based on the flatness data, a thickness profile of the strip for the hot rolling mill. Determining a target and controlling the thickness adjustment of the strip based on the thickness profile target as the strip passes through the hot rolling mill are performed.

A control system may send control signals to the hot rolling mill based on the thickness profile target to control the thickness profile of the strip. The control system may comprise, for example, a thickness profile controller and a flatness controller. In this case, the thickness profile controller and the flatness controller may comprise at least one data processor and at least one memory as defined above.

According to a further aspect, there is provided a production line comprising a hot rolling mill, at least one cold rolling mill downstream of the hot rolling mill, and a control system according to the present disclosure. A production line according to this aspect may be of any type according to the present disclosure.

Further details, advantages and aspects of the present disclosure will become apparent from the following embodiments in conjunction with the drawings.

FIG. 1 schematically represents a production line. FIG. 2 schematically represents a typical flatness model and a typical thickness profile target.

In the following, a method for controlling the flatness of a strip of rolled material in a production line, a control system for controlling the flatness of a strip of rolled material in a production line and a production line comprising the control system are described. Identical or similar reference numbers are used to indicate identical or similar structural features.

FIG. 1 schematically shows a production line 10. As shown in FIG. The production line 10 includes multiple hot rolling mills 12 and multiple cold rolling mills 14 . A cold rolling mill 14 is arranged downstream of these hot rolling mills 12 . In the example of FIG. 1 , the production line 10 includes two hot rolling mills 12 and five cold rolling mills 14 . Thus, production line 10 comprises a hot rolling side with hot rolling mill 12 and a cold rolling side with cold rolling mill 14 .

FIG. 1 further shows a strip 16 of rolled material, for example aluminum. In FIG. 1, strip 16 is conveyed to the right through each hot rolling mill 12 and each cold rolling mill 14 . In this example, the hot rolling mill 12 and the cold rolling mill 14 each comprise a multi-stand tandem rolling mill. In the first hot rolling mill 12, the strip 16 is a slab that is squeezed between rolls to reduce its thickness.

The manufacturing line 10 in this example further comprises a plurality of thickness profile measuring devices 18 . However, the production line 10 may alternatively include only one thickness profile measuring device 18 downstream of the last hot rolling mill 12 . Each thickness profile measuring device 18 is configured to measure the thickness profile of strip 16 . In the example of FIG. 1 , one thickness profile measurement device 18 is located upstream of the most upstream hot strip mill 12 and one thickness profile measurement device 18 is located upstream of the most downstream hot strip mill 12 . , and one thickness profile measuring device 18 is positioned between each pair of adjacent hot rolling mills 12 .

Each hot strip mill 12 comprises a plurality of rolls 20 and one or more mechanical actuators 22 for controlling the rolls 20 . Similarly, each cold rolling mill 14 includes multiple rolls 24 and one or more mechanical actuators 26 for controlling the rolls 24 . Each hot rolling mill 12 and each cold rolling mill 14 also includes a thermal actuator (not shown).

Each hot rolling mill 12 is configured to modify the thickness profile of strip 16 by means of its mechanical actuators 22 . To this end, each hot rolling mill 12 is controlled based on thickness profile targets. A thickness profile target indicates the change in thickness across the width of the strip 16 passing through the hot rolling mill 12 .

Each cold rolling mill 14 is configured to modify the flatness of strip 16 by means of its mechanical actuators 26 . To this end, each cold rolling mill 14 is controlled by one or more flatness models. Each flatness model defines a flatness effect on strip 16 caused by one of mechanical actuators 26 .

The production line 10 in this particular example further comprises a coiler 28 , an uncoiler 30 and a galvanizing or aluminizing station 32 . Coilers 28 , uncoilers 30 , and galvanizing or aluminizing stations 32 each constitute examples of subsequent processes for each of the cold rolling mills 14 . The production line 10 in this particular example further comprises a washing and pickling station 34 between the hot rolling side and the cold rolling side.

Manufacturing line 10 further comprises a plurality of shape meters 36 . Each shape meter 36 is configured to measure the flatness of strip 16 . In the example of FIG. 1 , one shaper 36 is located upstream of the most upstream cold rolling mill 14 and one shaper 36 is located downstream of the last cold rolling mill 14 . , one shaper 36 is positioned between each pair of adjacent cold rolling mills 14 . A profilometer 36 is also located downstream of the uncoiler 30 , ie between the uncoiler 30 and the galvanizing or aluminizing station 32 .

Manufacturing line 10 further comprises a control system 38 . Control system 38 includes at least one data processor 40 and at least one memory 42 . In FIG. 1, control system 38 is illustrated as comprising two data processors 40 and two memories 42 . The at least one memory 42 , when executed by one or more of the at least one data processors 40 , stores data in one or more of the at least one data processors 40 as described herein. It comprises program code that causes the various steps to be performed or directs the execution thereof.

In this particular example, control system 38 includes thickness profile controller 44 and flatness controller 46 . Each of thickness profile controller 44 and flatness controller 46 includes data processor 40 and memory 42 . However, control system 38 for controlling manufacturing line 10 may be implemented in different ways.

Flatness controller 46 controls cold mill 14 to minimize flatness errors based on signals received from cold mill 14 and/or shape meter 36 . Thickness profile controller 44 controls the hot mill to minimize thickness profile errors based on signals received from hot mill 12 and/or thickness profile measuring device 18 and from flatness controller 46 . 12 is controlled.

The deformation of the thickness profile of the strip 16 caused by rolling depends on the temperature of the strip 16, the aspect ratio of the strip 16, i.e., the width divided by the thickness, and the ratio of the coefficient of friction to the strip entry thickness. coefficient of friction to strip entry thickness). The dominant factor is the aspect ratio of strip 16 . For aspect ratios greater than 30, the deformation of strip 16 is essentially plane strain, ie, strip 16 decreases in thickness and increases in length with little or no change in width. In cold rolling, the aspect ratio is typically much higher than 30, especially when rolling thin strip 16 . On the other hand, in hot rolling, the aspect ratio will typically be less than 30, especially for the most upstream hot mill(s) 12, and thus profile deformation of the strip 16 will significantly increase the width of the strip 16. Occurs with growth.

The ability to vary the thickness profile of strip 16 decreases as the aspect ratio increases. Conversely, the ability to correct shape defects in strip 16 increases and is greatest at the last or most downstream cold rolling mill 14 .

Cold rolling associates the thickness profile of the strip 16 with the flatness of the strip 16 . This results in less flatness in cold rolling when it can provide a roll gap that reflects the entry thickness profile of the strip 16, ie equal elongation transverse the strip 16. It means that a defect exists or does not exist at all. The thickness profile of strip 16 is established primarily on the hot rolling side. Downstream of the hot rolling side, the strip 16 is too cold and too thin relative to its width to be able to change its thickness profile without causing shape problems. Therefore, it is difficult or impossible to vary the thickness profile of strip 16 on the cold rolling side without causing flatness problems.

FIG. 2 schematically represents an example of a typical flatness model 48 and a typical thickness profile target 50 . The flatness model 48 is a combination of a 2nd order polynomial and a 4th order polynomial. Flatness model 48 of mechanical actuator 26 is an example of flatness data associated with strip 16 in cold rolling mill 14 . Multiple flatness models 48 may be determined for one mechanical actuator 26 . In particular, one or more flatness models 48 may be determined for the mechanical actuators 26 of the most downstream cold rolling mills 14 .

The thickness profile target 50 of FIG. 2 is a second order polynomial. Thickness profile target 50 is 1% thicker at the center of strip 16 . Accordingly, the thickness profile target 50 of FIG. 2 has a crown of 1%.

As shown in FIG. 2, there is a mismatch between thickness profile target 50 and flatness model 48 . This mismatch makes it difficult for the cold mill 14 to maintain an entry thickness profile in the roll bite and thus achieve good flatness.

By matching the thickness profile target 50 more closely to the flatness model 48, the mechanical actuator 26 of the cold mill 14 can better cope with flatness errors due to its roll gap. To this end, flatness controller 46 is further configured to determine one or more flatness models 48 for one or more mechanical actuators 26 . Thickness profile controller 44 receives one or more flatness models 48 from flatness controller 46 and sets thickness profile targets 50 for one or more hot rolling mills 12 based on a combination of flatness models 48 . can be determined. The thickness profile target thus determined is not limited to polynomials or combinations of polynomials, but may be expressed in alternative ways. Thickness profile target 50 may include, for example, one or more flatness models 48, one or more measured flatnesses (eg, the flatness measured immediately downstream of the last cold rolling mill 14), and thickness may be determined by machine learning using the height profile target 50 as training data.

Thickness profile target 50 is based on one or more flatness models 48 that can actually be achieved by each mechanical actuator 26 . Therefore, the mechanical actuators 26 of the cold mill 14 can match the thickness profile from the hot mill 12 to reduce flatness errors.

Even if good flatness is obtained in the most downstream cold rolling mill 14, this flatness may change in subsequent processes, for example, as the strip 16 is wound and unwound. This variation may depend, for example, on cooling effectiveness and where within the coil a particular section of strip 16 is located. Accordingly, thickness profile target 50 may be determined based on the measured flatness of strip 16 after undergoing any of the subsequent processes 28 , 30 , 32 . Also, the measured flatness of the strip 16 constitutes an example of flatness data. As shown in FIG. 1, the flatness of strip 16 is measured just upstream of coiler 28 and just downstream of uncoiler 30 . The flatness effect due to winding and unwinding can then be determined based on the difference between these measured flatnesses. By determining the thickness profile target 50 based on flatness effects from winding and unwinding, the strip 16 can be made flatter after unwinding. Furthermore, flatness effects from winding and unwinding are addressed on the hot-rolled side rather than the cold-rolled side, thus reducing the risk of strip breakage.

While the disclosure has been described with reference to exemplary embodiments, it will be understood that the invention is not limited to that described above. For example, it will be appreciated that the dimensions of the parts may be changed as desired. Accordingly, it is intended that the invention be limited only by the scope of the appended claims.

Claims (12)

In a production line (10) comprising a hot rolling mill (12) and at least one cold rolling mill (14) downstream of said hot rolling mill (12), a strip (16) of rolled material is A method of controlling flatness, comprising:
in one or more of said at least one cold rolling mills (14) and/or after passing said strip (16) through one or more of said at least one cold rolling mills (14); , determining flatness data associated with said strip (16);
- determining a thickness profile target (50) of said strip (16) for said hot rolling mill (12) based on said flatness data;
- passing the strip (16) through the hot rolling mill (12) and adjusting the thickness of the strip (16) based on the thickness profile target (50);
How to prepare. Each cold mill (14) comprises at least one mechanical actuator (26) arranged to control one or more rolls (24) of said cold mill (14), said flatness The data comprises a flatness model (48) associated with one of said at least one mechanical actuator (26), wherein said flatness model (48) is a flatness model of said strip by said mechanical actuator (26). 2. The method of claim 1, wherein a flatness effect for (16) is defined. The production line (10) comprises a plurality of cold rolling mills (14) and the flatness data is selected from the at least one mechanical actuator (26) for the plurality of cold rolling mills (14). flatness models (48) associated with each of one or more of said hot rolling flatness models (48), wherein determination of said thickness profile target (50) best matches a combination of said flatness models (48) 3. The method of claim 2, comprising determining a thickness profile target (50) of the strip (16) for a machine (12). The production line (10) comprises a plurality of cold rolling mills (14), wherein the flatness data is the data of the at least one mechanical actuator (26) of the most downstream cold rolling mill (14). 4. Method according to claim 2 or 3, comprising one or more associated flatness models (48). The thickness profile target (50) includes the flatness model (48) associated with each of one or more of the at least one mechanical actuator (26) of the most downstream cold mill (14). 5. The method of claim 4, wherein the method is determined to reflect A method according to any one of claims 2 to 5, wherein the flatness model (48) depends on the width of the strip (16). A method according to any preceding claim, wherein the flatness data comprises a measured flatness of the strip (16). The flatness data comprises a measured flatness of the strip (16) after undergoing subsequent processes (28, 30, 32) for each of the at least one cold rolling mill (14). Item 7. The method according to item 7. A method according to any preceding claim, wherein said flatness data is determined by one or more shape meters (36). A method according to any preceding claim, wherein the thickness profile target is determined based on the width of the strip (16). In a production line (10) comprising a hot rolling mill (12) and at least one cold rolling mill (14) downstream of said hot rolling mill (12), a strip (16) of rolled material is A control system (38) for controlling flatness, said control system (38) comprising at least one data processor (40) and at least one memory (42) in which at least one computer program is stored. ), said at least one computer program comprising program code, said program code being executed by one or more of said at least one data processing apparatus (40), said at least one in one or more of the data processing devices (40),
in one or more of said at least one cold rolling mills (14) and/or after passing said strip (16) through one or more of said at least one cold rolling mills (14); , determining flatness data associated with said strip (16);
- determining a thickness profile target (50) of said strip (16) for said hot rolling mill (12) based on said flatness data;
- controlling the thickness adjustment of said strip (16) based on said thickness profile target (50) as said strip (16) passes through said hot rolling mill (12);
A control system (38) causing the execution of A production line comprising a hot rolling mill (12), at least one cold rolling mill (14) downstream of said hot rolling mill (12) and a control system (38) according to claim 11. (10).

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