Run-out strip cooling on a reversing rolling mill for cold-rolled metal strip

Abstract

According to the invention, a method for cold rolling a strip (2) in a reversing rolling mill (1) is carried out by means of a forward control or by means of an online control for at least one run-out cooling bar (20), (21) of the reversing rolling mill (1) such that the strip (2) does not exceed a predefined maximum temperature Tmax. The cooling bar (20), (21) is designed to apply coolant (22) during the cold rolling to an underside of the strip (2) as it runs out of a group of roll stands (10), (11). The forward control or the online control of the cooling bar is carried out using a sensitivity σ, which depends on a flow rate Φ of coolant through the cooling bar (20), (21), a strip speed vB and a strip thickness dB and is known in advance. Further second set-up values ∑i determined for the process of rolling the strip (2) are not influenced by the forward control or the online control according to the invention.

Description

[0001] 202400025 1 Description Strip cooling on the outlet side of a reversing rolling mill for cold-rolled metal strip. The invention relates to a method for cold rolling a strip in a reversing rolling mill by means of a forward control and by means of an online control of a cooling beam. Furthermore, the invention relates to a method for determining the sensitivity of a cooling beam on a reversing rolling mill for cold rolling strips. A reversing rolling mill for cold rolling flat, metallic rolled stock comprises a group of one or more rolling stands through which the rolled stock passes one or more times in alternating directions for the purpose of thickness reduction or surface treatment (skin passing). The rolling process itself takes place in such a reversing rolling mill at a maximum temperature of 150°C to 160°C.Rolled stock rolled on such a reversing rolling mill is generally made of steel and is referred to below as 'cold-rolled metal strip' or – within the scope of the invention – as 'strip'. In contrast, hot rolling takes place at significantly higher temperatures in a range of 600°C to 1000°C. In the following, the terms 'inlet side' and 'outlet side' in a reversing rolling mill refer to the strip travel direction in a currently considered rolling pass, so that between two consecutive rolling passes, the attribution of a work between 'inlet side' and 'outlet side' is reversed. A reversing rolling mill considered within the scope of the invention has two coiling devices, with the strip being unwound from one of the two draw coilers and wound onto the other draw coiler in each pass.Furthermore, such a reversing rolling mill has cooling and lubricating beams, by means of which the work rolls of the reversing rolling mill 2024P00025 2 and / or the strip can be directly cooled and lubricated by releasing an emulsion in order to support the thickness reduction process of the strip and dissipate the resulting forming heat. The cooling and lubricating agent is usually a lubricating emulsion, for example water with a proportion of up to 5% pure lubricant. The emulsion is always applied on the inlet side, viewed in the rolling direction, before passing through a respective stand of the reversing rolling mill, since applying the emulsion on the outlet side after passing through a rolling stand would result in this emulsion being carried over to a subsequent rolling stand or to the respective coiler.However, this omission of the application of emulsion on the outlet side means that the forming and frictional heat generated in the strip is often not sufficiently dissipated after it has passed through the rolling stand. In contrast to a tandem rolling mill, where the strip passes through all the stands one after the other without intermediate rewinding and is only then wound into a coil, the coiling of the strip after each pass also ensures that this heat is particularly well conserved. Furthermore, a reversing rolling mill considered in the context of the invention is controlled by an offline model that determines setup values ​​for the reversing rolling mill. Setup values ​​are generally default values ​​for the individual sections of the reversing rolling mill for rolling a specific strip.Specifically, the offline model can specify a number of passes through the group of rolling stands of the reversing rolling mill, also referred to as 'rolling passes'. Furthermore, it can include default values, for example, in the form of flow rates for cooling and lubrication beams, which lubricate and cool the work rolls or the roll gap, as well as specifications for the rolling stands or their drives with regard to thickness reduction and a rolling speed in the individual rolling passes. 2024P00025 3 The inlet and outlet rolling speeds of a strip in front of and behind a rolling stand are linked to each other via the continuity condition, see for example equation (3.9) on page 112 in H. Hoffmann, R. Neugebauer and G. Spur (eds.), "Handbuch Umformen", 2nd edition, Carl Hanser Verlag, 2012, ISBN 978-3-446-42778-5).Such offline models are known from the state of the art and work to determine the rolling passes and setup values ​​in a throughput-optimized manner, taking into account specified production parameters such as strip flatness, a permissible thickness tolerance of the strip, or a maximum permissible roll temperature. Such an offline model knows the technological limits of the respective reversing rolling mill, such as maximum possible rolling forces, strip speeds, flow rates through the cooling and lubrication beams, etc. However, a temperature or a temperature change of the strip, for example due to its cooling and forming in the reversing rolling mill, is not determined by such offline models. Offline models are implemented, for example, on a separate calculation unit that transmits the setup values ​​determined by an offline model to the control unit of the reversing rolling mill.In summary, the invention relates to a reversing rolling mill with a group of one or more rolling stands for cold rolling the strip in one or more rolling passes i and at least one coiling device for winding and unwinding the strip on each side of the group of rolling stands before and after the individual rolling passes. Furthermore, the reversing rolling mill comprises at least one cooling and lubricating beam for applying a coolant and lubricant to the inlet side on each side of each individual rolling stand. Furthermore, the reversing rolling mill comprises at least one cooling beam on at least one side between the group of rolling stands and the coiling device. The cooling beam(s) are(s) for applying coolant to an underside of the strip 2024P00025 4, which is(are) supplied by the cooling beam(s).The cooling beam is set up at a flow rate ^ when the strip exits the group of rolling stands and is therefore located below a transport plane of the strip. The impact on the underside of the strip serves to achieve a temperature change ^T in the strip. The term 'side' here refers to a vertical plane through a rolling stand, with the strip passing essentially horizontally through the rolling stand during rolling. The group of rolling stands can comprise only one rolling stand, but can instead also have two rolling stands (double reversing stand) or even more rolling stands. The essential fact is that the strip passes through the group of rolling stands as a whole in an alternating (horizontal) direction, so that in two consecutive rolling passes the entry and exit directions of the strip are reversed with respect to the individual rolling stands.The aforementioned circumstances mean that strip rolled in a reversing mill becomes significantly hotter than if it were rolled in a tandem mill with the same degree of deformation. Strip temperatures above 160°C are particularly undesirable, as this can have a negative impact on strip quality and places special demands on the equipment used. For example, the oil from the emulsion burns on an overly hot strip surface, leaving stains. Roll gap lubrication is also negatively affected, as the oil in the emulsion loses viscosity. Flatness control becomes difficult when the strip is too hot. The corresponding coil deposits suffer from high coil temperatures and wear more quickly. Finally, coils that are too hot must cool down before they can be processed further, which reduces the throughput of the reversing mill in question.As a consequence, measures can be taken on the reversing rolling mill which indirectly reduce and limit the strip temperature, e.g. a reduction in the rolling speed or smaller thickness reductions per rolling pass, which produces less forming energy. However, these measures can also have a negative impact on throughput or product properties. Devices for actively cooling a strip in a cold rolling mill are also known from the prior art. For example, WO 2014 / 167138 A1 shows a cooling device for the underside of a strip during rolling in a cold rolling mill, wherein the underside of the strip is subjected to low-pressure turbulence cooling. JP S61242715(A) also discloses a cooling box for a strip in a cold rolling mill, wherein the strip is passed through the cooling box and is cooled on its top and bottom sides by means of cooling water.The cooling box forms a narrow flow channel for the cooling water on both the top and bottom surfaces of the strip and has corresponding sealing rollers that seal the cooling box against the escape of cooling water. To improve heat transfer between a strip-shaped rolled stock and a cooling medium applied to it, WO 2014 / 095268 A1 proposes a cooling device with a cooling chamber extending in the direction of strip travel, which extends the exposure time of the cooling medium. The supply of the cooling medium can be controlled depending on various parameters, such as the temperature of the rolled stock or the residual cooling medium remaining on the rolled stock after passing through the cooling device. A common feature of the solutions proposed by WO 2014 / 167138 A1, JP S61242715(A) and WO 2014 / 095268 A1 is a chamber-like structure in which the cooling medium contacting the cold-rolled strip is guided.However, this results, firstly, in increased space requirements and, secondly, in poor controllability, because temporal changes in the cooling effect can only be implemented much more slowly than is possible, for example, with the help of cooling beams due to the large liquid volume of the respective chamber-like structure. Furthermore, it is known from WO 2021 / 048038 A1 to specify a temperature window for a rolled stock during cold rolling in a rolling mill with several rolling stands and to ensure, through various control and regulation measures, that the rolled stock temperature remains within the temperature window during rolling. The measures include heating the rolled stock before a rolling pass, cooling and lubricating work rolls orof the rolling stock itself by means of appropriate cooling and lubrication beams, the creation of an appropriate pass schedule distribution to account for the forming heat generated during rolling, and the control and regulation of a rolling speed to account for the frictional power losses generated in a rolling stand. The effect of these control and regulation measures on the rolling stock temperature can be simulated in advance, i.e., before the actual rolling process, either on the basis of empirical values ​​in the form of an empirical model or using a physical model, and the setup values ​​for the respective sections of the cold rolling mill can be adjusted accordingly. In addition, the temperature of the rolling stock can be measured during rolling, and a control or regulation measure can be adjusted online.However, WO 2021 / 048038 A1 does not specifically address the above-described problem of particularly intense heating of strips in reversing rolling mills. Furthermore, predetermining the correct setup values ​​can require multiple iterations, each containing one or more physical models, which entails significant computational and time-consuming efforts, since all components of the cold rolling mill must be considered in their entirety. 2024P00025 7 Finally, JP H02220701 A teaches keeping the temperature of an austenitic steel strip as high as possible during cold rolling to increase productivity. For this purpose, a strip temperature is recorded in each rolling pass, and the applied cooling rate is adjusted accordingly so that a maximum temperature of 180-200°C is not exceeded.It is therefore an object of the present invention to prevent undesirably high temperatures during the rolling of a strip in a reversing rolling mill using simple structural and control means, without negatively influencing throughput. In addition, the determination of default values ​​for maintaining a predetermined maximum temperature for the strip to be rolled is to be simplified. This object is achieved according to the invention by a method according to claim 1. Preferred embodiments of the method according to the invention are the subject of the dependent method claims. In the method according to the invention for cold rolling a strip in a reversing rolling mill described above in one or more rolling passes i, in the form of a forward control of the cooling beam, before at least one, preferably before all rolling passes i, in thein which at least one of the cooling beams acts as an outlet-side cooling beam, a maximum temperature Tmax is initially specified for the strip, and a first setup value ^i for a flow rate ^ of coolant for all cooling beams is set to a value of 0. Consequently, in the case that the cooling beam(s) are arranged on only one side (relative to a strip running direction) between the group of rolling stands and one of the coiling devices, the method according to the invention is applied at most in every other rolling pass. Otherwise, at least one outlet-side cooling beam is present in each rolling pass, so that in this case the method according to the invention can be applied in every rolling pass. 2024P00025 8 A characteristic temperature T is then determined. cof the strip, which can be a temperature value of a strip surface, in particular a bottom or a top side of the strip, and it is checked whether the characteristic temperature T c the maximum temperature T max exceeds: if this is the case, the first setup value ^i for the downstream chilled beam(s) is determined based on a sensitivity ^. The sensitivity ^ describes the temperature change ^T achieved in the belt due to the application of the coolant and is defined as a functional relationship with at least the flow rate ^and a belt speed v B known. Finally, the rolling pass i is carried out under specification of the determined first setup value ^i for the outlet-side cooling beam(s). In concrete terms, this means that if the maximum temperature T maxby the temperature Tc characteristic of the strip, is determined based on a sensitivity ^first setup value ^i greater than zero for a flow rate ^ of coolant for the exit-side cooling beam(s), and at rolling pass i, the exit-side cooling beam(s) are subjected to the determined setup value ^i; otherwise, the exit-side cooling beam(s) remain inactive, i.e., no coolant is released from the cooling beam onto the strip. The cooling beam(s) located on the inlet side of the group of rolling stands always remain inactive in each rolling pass i. The maximum temperature T maxcan, for example, be based on empirical values ​​regarding strip cracks during rolling and can be selected depending on the material composition of the strip and is preferably in a range of 120°C to 160°C. Physically, the sensitivity ^ has the meaning of a temperature difference that is caused by the activated, outlet-side cooling beam(s) as a function of at least its flow rate(s) ^ in the strip. According to the invention, the sensitivity ^ is defined as a previously known 2024P00025 9 functional relationship between the temperature change ^T induced in the strip with at least the flow rate ^ and a strip speed v B provided. The belt speed v B can also be assumed to be known for the rolling pass i, since they are determined in advance by an offline model, for example, during the pass plan creation. At the strip speed v Bit can be a belt inlet speed v i,in or to achieve a belt run-out speed v i,ex of the strip rolled in the respective rolling pass i. The functional relationship can, for example, be an empirically determined relationship between the temperature change ^T induced in the respective strip and the set flow rate ^ and the strip speed vB. However, the sensitivity ^ can also be based on a physical model as a function between the induced temperature change ^T and the set flow rate ^ and the strip speed vB. If the functional relationship is known with sufficient accuracy, the setup value ^i can, for example, be determined such that the strip is heated by the activated cooling beam exactly to the maximum temperature T max is cooled down, ie the characteristic temperature T cof the belt after it has passed the chilled beam corresponds exactly to the maximum temperature Tmax. However, the setup value ^i can also be selected, particularly in the case of only a roughly known functional relationship between the temperature change ^T on the one hand and the flow rate ^ and the belt speed vB on the other hand, so that the characteristic temperature T c of the strip after passing the chilled beam, the maximum temperature T maxin any case falls below this value. Mathematical methods for finding a specific variable value of a function or a functional relationship between an output variable and several input variables for which the function value or the output variable is specified are generally known and are not the subject of the invention. The use of a known sensitivity ^ thus offers the advantage that in order to determine the setup value ^i, only the following equation (1) needs to be solved for the desired value for ^i, which can be done with limited computing effort, for example by means of a control unit of the reversing rolling mill within less than 10 ms. The first setup value ^i is specified, for example, by transmission from a separate calculation unit to a control unit of the reversing rolling mill, which controls its individual sections (such as the rolling stands, the coiling devices, the cooling and lubrication beams as well as thethe cooling beams). In the method according to the invention, only the setup values ​​for the cooling beams on the outlet side are changed in a respective rolling pass i, but not the other setup or default values ​​for the remaining sections of the reversing rolling mill; in particular, a pass schedule for the strip remains unchanged. The cooling beam(s) on the outlet side thus only act as an additional actuator, which is why the method according to the invention is particularly well suited as a retrofit solution for an existing reversing rolling mill: such a mill can, for example, be retrofitted with additional cooling beams for cooling an outgoing strip with relatively little investment outlay, whereby an existing offline model, which is already adapted to the technological conditions of the mill, does not have to be modified. Furthermore, the cooling beams are only switched on when the maximum temperature T is exceeded. maxthe respective outlet-side cooling beam(s) is / are activated, which is why the method according to the invention represents a minimal, independent control-technical intervention in the operation of the reversing rolling mill, which advantageously only minimally increases the complexity of the plant control system. 2024P00025 11 The application of coolant to the underside of a strip leaving the group of rolling stands also advantageously represents a technically simple option for strip cooling, because the coolant largely flows downwards automatically due to the effect of gravity and any remaining residues are squeezed off by a usually present deflection roller in front of the downstream coiler. A collecting device for the coolant and lubricant, which is usually already present on the rolling stands, can also be used, so that no additional collecting devices for the cooling beams need to be provided.According to a further preferred embodiment of the method according to the invention, the sensitivity ^ - in addition to the flow rate ^ and the strip speed vB - is additionally determined as a functional relationship with a strip thickness d. B known, so that the temperature change induced in the band ^T can be represented according to the relationship ^T = ^(^ = ^i; vB; dB) (1). The band thickness d B can in turn - analogous to the belt speed v B - for the rolling pass i can be assumed to be known, where the strip thickness d B by a strip inlet thickness d i,in or a strip outlet thickness d i,ex in relation to one of the rolling stands of the reversing rolling mill. Thus, in this embodiment, the setup value ^i is determined such that the sensitivity ^ corresponds to the temperature change ^T in the strip according to equation (1). In this embodiment, the strip speed v B and and the strip thickness d Bof the strip rolled in the respective rolling pass i must be taken into account, so that the temperature change ^T can advantageously be set very precisely. For example, cooling of the strip can be carried out particularly energy-efficiently by appropriately determining the setup value ^i and cooling the strip only to such an extent that the temperature change ^T essentially corresponds to the difference between the characteristic temperature T c and maximum temperature T max corresponds, so that the cooling only prevents the specified maximum temperature T max According to a preferred embodiment of the method according to the invention, the characteristic temperature T c determined on the basis of an empirical model or a physical model. In an empirical model, the characteristic temperature T cfor example, from input parameters, including material properties, parameters of the pass schedule and production parameters (these include, for example, a strip infeed speed v i,in and / or a belt run-out speed v i,ex and / or a rolling force in the rolling pass i) of a strip in question can be quickly determined or interpolated if corresponding values ​​for the characteristic temperature T c For example, in the form of previously determined calculation values ​​or in the form of empirical values ​​or operator inputs. Using a physical model, a characteristic temperature T cadvantageously be calculated directly and particularly accurately based on the same or similar input parameters; in this context, WO 2021 / 048038 A1, for example, discloses determining an exit temperature of a rolling stock behind a rolling stand prior to the actual rolling process based on the entry temperature of the rolling stock in conjunction with modelable physical heat flows. According to a particularly preferred embodiment of the method according to the invention, prior to determining the characteristic temperature T c using a physical model, assuming that the flow rate ^ is zero, based on a given belt runout speed v i,ex and a specified strip outlet thickness d i,exfor the strip and based on second setup values ​​^i for the at least one 2024P00025 13 cooling and lubricating beam, starting from an initial temperature T0 of the strip, a temperature distribution ^ of the strip is determined by solving a heat conduction equation of the physical model in a region B, which includes at least a section of the strip. The characteristic temperature Tc is then derived or determined from the temperature distribution ^. By solving a heat conduction equation, the characteristic temperature T c , which the strip has or would have after the rolling pass with the exit-side cooling beam deactivated, can advantageously be predicted particularly precisely, so that any necessary exposure of the strip to coolant can be specifically targeted and adjusted. At the characteristic temperature T cFor example, it can be a temperature value of the strip averaged over the functional coordinates of the temperature distribution ^ or a temperature value at a strip surface. The temperature distribution ^ is a function of the temperature within the strip as a function of the spatial coordinates. Within the framework of the feedforward control according to the invention, a thermally stationary state of the strip in the reversing rolling mill is assumed, i.e., it is approximately assumed that the temperatures and temperature changes of the strip are the same over its entire length during the rolling process. Therefore, the region B, which comprises a specific section of the strip at each time considered in the heat conduction equation, can be considered spatially fixed with respect to the rolling stands.As a result, the coordinate system of the heat conduction equation is not fixed with respect to the strip itself, which moves through the rolling stands in rolling pass i. The rolling speeds relative to the individual rolling stands are only included as parameters in the heat conduction equation or in the boundary conditions of area B. The heat conduction equation can therefore be solved in the considered area B with corresponding initial and boundary conditions for the strip. 2024P00025 14 For the initial temperature T0, for example, a value corresponding to the ambient temperature can be used for the first rolling pass, since the strips in question are usually stored for a long time in the reversing rolling mill before rolling. In addition, a constant temperature distribution of the strip upon entry into the considered area B can be assumed, since the temperature quickly uniforms in the strip thickness direction during the winding processes between the rolling passes.For further rolling passes, the initial temperature T0 can be, for example, the characteristic temperature value T determined for the immediately preceding rolling pass. cbe assumed, since the strip is wound into a coil on the reversing rolling mill immediately after each rolling pass and in this state negligible heat is released into the environment during the period between two rolling passes. Alternatively, the initial temperature T0 for further rolling passes after the first rolling pass can also be assumed based on empirical values, since the average strip temperature usually approaches an upper saturation temperature after just a few rolling passes: therefore, an initial temperature T0 for further rolling passes can be obtained with a good approximation, for example, from the temperature measurement of a strip with a comparable final thickness immediately after its rolling on the reversing rolling mill. The cooling and lubricant applied during rolling by at least one cooling and lubrication beam conducts heat away from the working rolls orfrom the strip and is included in the heat conduction equation as a boundary condition via corresponding heat transfer coefficients. Furthermore, the heating due to the plastic deformation of the strip and the friction between the strip and the work rolls in the roll gap must be taken into account in the form of so-called source terms. The consideration of such boundary conditions and source terms is known, for example, from WO 2021 / 048038 A1 or from F. Hell: Fundamentals of Heat Transfer, VDI-Verlag 1982, ISBN number 2024P00025 15 978-3-18-400529-0, Chapters 2.2 and 2.3, formulas (81) to (83) in conjunction with Figure 25 and Tables VI and VII.According to a preferred embodiment of the method according to the invention, the region B in which the heat conduction equation is solved extends, viewed in the strip travel direction, at least from the beginning of a first effective region W of the first inlet-side cooling and lubrication beam to at least the end of a second effective region W' of the last outlet-side cooling beam. The first and second effective regions W, W' therefore essentially comprise those regions in which the cooling and lubricating agent or the coolant comes into contact with the surface of the strip.Both areas are spatially limited because the beams only have a limited spray width in the direction of strip travel, because the coolant and lubricant are only applied on the inlet side and are therefore only transported by the strip as far as the rolling stands, from where it is discharged laterally, and because the coolant is only applied to the underside of the strip, where, due to the effect of gravity, contact with the strip surface in this area is also spatially limited. Thus, area B taken into account by the heat conduction equation does not include the coiling devices and the distance between these and the rolling stands, but these influences on the strip temperature can be neglected. On the other hand, area B includes all sections of the reversing rolling mill that actively influence the strip and have corresponding heat sources in the strip (e.g. due to plastic deformation in the rolling stands) and heat flows into the strip orfrom the strip (friction between the strip surface and the work rolls in the roll gap, influence of the cooling and lubrication beams or the cooling beams). The selected extension of area B advantageously enables a realistic determination of the strip temperature in the individual rolling passes and limits the computational effort required for this. 2024P00025 16 In a preferred embodiment of the method according to the invention, the work rolls of the rolling stands are also included in the heat conduction equation. This means that in addition to the volume of the strip considered in area B, a volume of the work rolls themselves or their heating is also taken into account. This advantageously allows a more precise determination of the temperature distribution ^ of the strip because, in addition to the frictional heat between the strip and the work rolls, the direct heat flows between the strip and the work rolls are also taken into account.In a further preferred embodiment of the method according to the invention, the heat conduction equation is applied as a one-dimensional differential equation, and the temperature distribution ^ is determined in the thickness direction of the strip. Since the thickness d of a strip rolled on the respective reversing rolling mill is generally between 0.1 mm and 7 mm and is thus significantly smaller than its width (at least 600 mm) and its dimension along the considered area B (several meters), heat flows in the longitudinal and strip width directions can be neglected to a good approximation. Advantageously, with such a one-dimensional heat conduction equation, the computational effort for determining the temperature distribution ^ can be kept low.In the method according to the invention for cold rolling a strip in a reversing rolling mill described above in one or more rolling passes i relating to an online control of a cooling beam, a maximum temperature T is reached before at least one of the rolling passes i, in which at least one of the cooling beams acts as an outlet-side cooling beam. maxfor the strip. Again, this means that this method according to the invention is also applied at most every other rolling pass if the cooling beam(s) are arranged only on one side (relative to a strip running direction) between the group of rolling stands and one of the coiling devices. Otherwise, at least one cooling beam is present on the exit side in each rolling pass, so that in this case the method according to the invention can be applied to every rolling pass. Furthermore, during the at least one rolling pass i under consideration, a current exit temperature T is measured cyclically, i.e. repeatedly at respective time intervals ^t, by means of a temperature detection device. i,ex " of the belt. In the event that the outlet temperature T i,ex " the maximum temperature T maxexceeds, a first setup value ^i for the outlet-side cooling beam(s) is determined in the respective time interval ^t based on a sensitivity ^ already mentioned, which in turn is a function of at least the flow rate ^ and a strip speed v known for the rolling pass i B is known. At the belt speed v B This can again be a belt speed determined in advance, for example, during the preparation of the pass schedule. Preferably, however, in some, particularly preferably in all, time intervals ^t, an instantaneous belt speed v B " as known belt speed v B– for example, by reading a corresponding instantaneous speed signal from a work roll of one of the rolling stands. Subsequently, in the respective time interval ^t, the first setup value ^i is specified for the outlet-side cooling beam(s), i.e., the flow rate ^ of coolant through the cooling beam(s) is set to the determined setup value ^i. The temperature detection device can be a pyrometer, for example. This is especially true if an instantaneous strip speed v is required to determine ^i. B " is used, the flow rate ^ of the cooling beam can be advantageously adjusted particularly precisely to the current rolling situation. The deviation of the current strip speed v B" from a fixed setup value is a frequently occurring situation on a reversing rolling mill, for example because the setup value is subsequently changed by a basic automation system of the reversing rolling mill or by an operator to a different value. B " is set. This method according to the invention advantageously enables an even more precise setting of an outlet-side strip temperature, because instead of a mathematically determined temperature value, a momentary - ie a temperature value T determined or recorded for the relevant moment - is used. i,ex"is used to determine the flow rate ^. Because the recording of the outlet temperature and the corresponding adjustment of the flow rate of the outlet-side cooling beam(s) takes place periodically at time intervals ^t, any changes in the rolling conditions, such as a changing strip inlet temperature or an irregular lubrication and cooling effect of the cooling and lubrication beam(s) over the strip length, can be directly controlled. The time intervals ^t preferably have an interval duration of a maximum of 10 ms, whereby the adjustment of the flow rate ^to the current outlet temperature T i,ex " advantageously particularly promptly. In a further preferred embodiment of the method according to the invention relating to an online control of the outlet-side cooling beam, the sensitivity ^ is additionally defined as a functional relationship with a strip thickness d B known. The strip thickness d Bcan again be assumed to be known for the rolling pass i - analogous to the method according to the invention relating to the forward control of a cooling beam. Accordingly, in this embodiment, the first setup value ^is determined in such a way that the sensitivity ^ corresponds to the temperature change ^T in the strip according to equation (1) and can therefore advantageously be set very precisely. According to a preferred embodiment of the method according to the invention, the temperature detection device is arranged at a distance a behind the end of a second effective range W' of the last cooling beam on the outlet side, as seen in the strip travel direction. The arrangement at a distance a ensures that the cooling effect on the strip is correctly detected, since the temperature distribution in the outgoing strip becomes uniform as it passes through the distance a until the measurement by the temperature detection device ('through cooling' in the strip thickness direction).The distance a is, for example, 0.5 m to 1.5 m, preferably 0.8 m to 1.0 m. Overall, a temperature detection device is arranged on each side of the group of rolling stands on the reversing rolling mill. The properties, features, and advantages of the invention described above, as well as the manner in which they are achieved, will become clearer and more easily understood in connection with the description of the following exemplary embodiment of the invention, which is explained in more detail in conjunction with the figures. Identical parts and sections in the figures are provided with the same designations.They show: Figure 1 (FIG 1) a cross section through a reversing rolling mill to which the method according to the invention can be applied; Figure 2A (FIG 2A) an embodiment of a method according to the invention with the aid of a feedforward control; Figure 2B (FIG 2B) an embodiment of a method according to the invention with the aid of an online control; Figure 3A (FIG 3A) a flow chart of an embodiment relating to a feedforward control; Figure 3B (FIG 3B) a flow chart of an embodiment relating to a feedforward control with a physical model; Figure 3C (FIG 3C) a flow chart of an embodiment relating to an online control; and 2024P00025 20 Figure 4 (FIG 4) a detail from a reversing rolling mill relating to a physical model for a feedforward control.In general, the cold rolling mill 1 shown in FIGS. 2A, 2B, and 4 can each be configured as shown in FIG. 1, but can also have a different number of rolling stands 10, 11, coiling devices 30, 31, 32, cooling beams 20, 21, or cooling and lubricating beams 13, 14, 13', 14', without affecting the method described with reference to the respective figures. FIG. 1 shows a cross-section through a reversing rolling mill 1 designed as a double reversing rolling mill and comprising a group of two rolling stands 10 and 11, each having an upper work roll 12 and a lower work roll 12', as well as an upper and a lower backup roll 18 and 18', respectively. The upper and lower work rolls 12 and 12' of the rolling stands 10 and 11 each form a roll gap through which the strip 2 is passed in one or more rolling passes along a so-called pass line 4 for the purpose of thickness reduction.To the left of the group of rolling stands 10 and 11, the reversing rolling mill 1 has a coiling device 30. To the right of the rolling stands 10 and 11, two further coiling devices 31 and 32 of the reversing rolling mill 1 are arranged. In each rolling pass of the exemplary embodiment shown in FIG. 1, the strip 2 passes through both rolling stands 10 and 11 of the group in alternating directions, with the current strip travel direction 5 in FIG. 1 being indicated by a horizontal arrow running from right to left, and the directions of rotation of the coiling devices 31 and 30, which function as uncoiling and recoiling devices, also being indicated by corresponding arrows. On the coiling device 32, a further strip 2' is wound, which can be rolled after the strip 2 on the reversing rolling mill 1, while the 2024P00025 21 strip 2 is still on the coiling device 31 after its last rolling pass.On both sides (relative to a strip running direction 5) of the group of rolling stands 10 and 11, upper and lower cooling and lubricating beams 13 and 13' are arranged, respectively, which are designed to apply a coolant and lubricant 16 (see FIG. 2A) into the roll gap. In addition, on both sides of the rolling stands 10 and 11, upper and lower cooling and lubricating beams 14 and 14' are arranged, respectively, for applying a coolant and lubricant 16 to the respective work roll 12 or 12'. As a rule, in a given rolling pass, only the cooling and lubricating beams 13, 13', 14, 14' located on the inlet side are active and release coolant and lubricant 16 onto the work rolls 12, 12' or in the direction of the roll gap: this is shown in more detail in FIG. 2A and FIG. 2B. Furthermore, below the strip and in the strip running direction 5, a cooling beam 20 and 21 is arranged in front of and behind the rolling stands 10 and 11 for dispensing a coolant 22 onto an underside 2' of the strip 2.In FIG. 1, for example, the cooling beam 20 currently on the outlet side is active, wherein in principle the contact area between the coolant 22 emitted by the cooling beam 20 or 21 and the underside 2' of the belt 2 forms a second effective area W' of the respective cooling beam 20, 21. In addition, in the belt travel direction 5, a respective temperature detection device 40 or 41 is arranged at a distance a behind the end of the second effective area W' of the respective cooling beam 20, 21 above the belt 2. The arrangement of the temperature detection devices 40, 41 above and the cooling beams 20, 21 below the belt 2 prevents residual coolant from remaining on an upper side 2" of the belt, so that the temperature of the belt 2 can be detected by means of the temperature detection devices 40, 41 largely without interference.2024P00025 22 Furthermore, on each side of the group of rolling stands 10, 11, viewed in the strip travel direction 5, a deflection roller 35 is arranged below the fitting line 4 behind the cooling beam 20 or 21. During winding, the strip 2 is guided downwards by the respective deflection roller 35 in the direction of the corresponding coiling device 30, 31, 32, whereby any adhering residues of coolant 22 applied to the strip by means of the cooling beam 20 or 21 are stripped off. FIG. 2A shows an embodiment of the method according to the invention relating to forward control on a reversing rolling mill 1 according to FIG. 1; for reasons of clarity, therefore, only the most important sections are provided with identifiers. In contrast to FIG 1, the strip running direction 5 in the rolling pass i shown in FIG 2A runs from left to right: the strip 2 is wound by the coiler device 30 with a strip thickness d. B , which is identical to a strip inlet thickness d i,inis unwound, occurs with a strip entry speed v i,in into the group of rolling stands 10, 11 or with a strip exit speed v i,ex and a strip outlet thickness d i,exfrom this again and is wound onto the closer coiling device 31; the respective directions of rotation of the coiling devices 30 and 31 are indicated by corresponding arrows. The coiling device 32 is not involved in the rolling pass shown in FIG. 2A, but can, for example, already be loaded with a strip 3 to be rolled subsequently. In a separate calculation unit 60, an offline model 100 is implemented, which determines second setup values ​​^i for the individual sections of the reversing rolling mill 1 for at least one rolling pass i (symbolized by curved brackets). The second setup values ​​^i are transmitted to a control unit 50 of the reversing rolling mill 1 and include, among other things, default values ​​for the delivery of coolant and lubricant 16 to the work rolls 12, 12' or into the roll gap, as well as for the strip entry speed v i,in and / or the belt run-out speed v i,exas well as for the 2024P00025 23 strip inlet thickness d i,in and / or the strip outlet thickness d i,exin rolling pass i. The control unit 50 controls the individual sections of the reversing rolling mill 1 in the illustrated rolling pass i according to the second setup values ​​^i, which is represented in FIG. 2A by corresponding upward-pointing arrows. In this context, 'control' means the transmission of control signals or control commands to the respective section both with and without feedback, with feedback being symbolized in FIG. 2A by a downward-pointing arrow. Furthermore, FIG. 2A shows that the calculation unit 60 determines a first setup value ^i for the cooling beams 20 and 21 for at least one rolling pass i in advance, ie before the strip 2 is actually rolled on the reversing rolling mill 1, and transmits this to the control unit 50.In the rolling pass specifically shown in FIG 2A, the default value for the inlet-side cooling beam 20 is set to 0, while the setup value ^i for a flow rate ^ of coolant 22 through the outlet-side cooling beam 21 is greater than 0: consequently, in contrast to the outlet-side cooling beam 21 in the rolling pass i shown, no coolant is delivered to the underside 2' of the strip 2 from the inlet-side cooling beam 20 (shown in dashed lines). If the calculation unit 60 is only provided with the strip inlet speed v. i,in and the strip inlet thickness d i,in are known, the calculation unit 60 can, for example, use the pass reduction in the relevant rolling pass i to determine the corresponding strip run-out speed v i,exand strip outlet thickness di,ex automatically. The setup value ^i for the outlet-side cooling beam 21 is determined using a sensitivity ^, whereby according to the invention a characteristic temperature T c of band 2, which has a maximum temperature T max FIG. 2B shows an embodiment of the method according to the invention relating to online control on a reversing rolling mill 1 according to FIG. 1; for reasons of clarity, only the most important sections are provided with identifiers. Furthermore, only the differences from the method shown in FIG. 2A are described below. Again, an offline model 100 is implemented on a separate calculation unit 60, which calculates second setup values ​​^i for at least one rolling pass i (again symbolized by curved brackets) - again comprising a strip entry speed v i,in and / or a belt run-out speed vi,ex and a strip inlet thickness d i,in and / or a strip outlet thickness d i,ex in the rolling pass i - for the individual sections of the reversing rolling mill 1 and transmitted to a control unit 50 of the reversing rolling mill 1. Likewise, a maximum temperature T max for the strips. In contrast to FIG 2A, no first setup value ^i is determined in advance for the cooling beams 20 and 21, but instead, in the considered rolling pass i, a current outlet temperature T is determined cyclically at time intervals ^t by means of a temperature detection device 40, 41 i,ex" of the strip 2 is recorded and transmitted to the control unit 50: in the rolling pass i shown in FIG 2B, the temperature detection device 40 would measure an inlet-side temperature of the strip 2, which, however, is not used further in this specific case, which is why the corresponding connecting arrow to the control unit 50 is shown in dashed lines. In each time interval ^t, the current outlet temperature T i,ex " with a given maximum temperature T max compared: if the current outlet temperature T i,ex " greater than the maximum temperature T maxis (which applies to the case shown in FIG. 2B), a default value ^i for a flow rate ^ of coolant 22 through the cooling beam 21 located on the outlet side is determined using a sensitivity ^, which is defined as a functional relationship between the temperature change ^T caused in the strip 2 by the activated cooling beam 21 and the flow rate ^ set on the cooling beam 21, the strip outlet speed vi,ex and strip outlet thickness d i,ex is known. Again, from the strip inlet speed v i,in and the strip inlet thickness d i,in For example, the corresponding strip run-out speed v is determined via the pass reduction in the relevant rolling pass i i,ex and strip outlet thickness d i,exThe repeated, cyclical determination of the setpoint value ^i in each time interval ^t is indicated in FIG. 2B by a corresponding round arrow symbol within the control unit 50. Subsequently, the control unit 50 sets the flow rate of coolant 22 through the outlet-side cooling beam 21 to the determined setpoint value ^i, while the inlet-side cooling beam 20 remains deactivated during the entire rolling pass i and is therefore shown in dashed lines in FIG. 2B. As an alternative to the strip inlet speed v determined by the offline model 100, i,in or belt run-out speed v i,ex can also be a current tape run-out speed v i,in"or instantaneous strip exit speed vi,ex" can be used to determine the setpoint value ^i, which is indicated in FIG. 2B by symbols in curly brackets. FIG. 3A shows a flowchart for an embodiment of a method according to the invention relating to a feedforward control. According to the prerequisite, before at least one rolling pass i is carried out, second setup values ​​^i are determined by an offline model 100 for the individual sections of the reversing rolling mill 1 - excluding the cooling beams 20, 21. Furthermore, according to the prerequisite, a sensitivity ^ is known, which describes the effect of the cooling beam 20, 21 of the rolling pass under consideration in the reversing rolling mill 1 on a temperature change ^T of the strip 2 cold-rolled therein due to the effect of the exit-side cooling beam 20, 21.2024P00025 26The sensitivity ^ depends at least on a flow rate ^ of coolant 22 applied to the underside 2' of the belt 2, which corresponds to the specified value ^i to be determined for the respective cooling beam 20, 21, and a belt speed v. B - specifically from the belt run-out speed v i,ex , with which the strip 2 passes the respective outlet-side cooling beam(s) 20, 21 after passing through the group of rolling stands 10, 11. In addition, in the embodiment shown in FIG. 3A, a functional dependence of the sensitivity on a strip thickness d B - specifically from the strip outlet thickness d i,ex, - is assumed, which is also assumed to be known. For at least one rolling pass i, preferably for all rolling passes i, the following steps are carried out if the corresponding second setup values ​​^i are available (but still before the actual rolling pass i itself): First, a maximum temperature T max and a first setup value^i for a flow rate ^ of coolant 22 through at least one outlet-side chilled beam 20, 21 is initially set to a value of 0: the outlet-side chilled beam 20, 21 is thus initially assumed to be inactive. A characteristic temperature T cof the strip 2 - e.g. a temperature at the bottom 2' or at the top 2" of the strip 2 - is determined on the basis of an empirical model 110. In other words, the effect on the temperature of the strip in the rolling pass i with deactivated (outlet-side) cooling beams is simulated on the basis of empirical values. In the case that the characteristic temperature T c greater than the maximum temperature T max is, the first setup value ^i for the outlet-side cooling beam 20, 21 in the considered rolling pass i is determined based on the sensitivity ^ such that the sensitivity ^ corresponds to the temperature change ^T induced in the strip 2, which in the concrete embodiment is the difference between the characteristic 2024P00025 27 temperature T c and the maximum temperature T maxis assumed. Alternatively, a larger value for the temperature change ^T can be selected, which allows for a stronger cooling of band 2 below the maximum temperature T max The determined first setup value ^i for the outlet-side cooling beam(s) 20, 21 are transmitted together with the second setup values ​​^i, for example, to a system control 50 as soon as the rolling pass i is carried out. The transmission of data is symbolized in FIG 3A by thin arrows. The optional execution of the last step depending on the exceeding of the maximum temperature T max is shown in FIG 3A by corresponding dashed arrows. In summary, in the method according to the invention relating to a pre-control, an outlet-side cooling beam 20, 21 is only activated (and subsequently the belt 2 is supplied with coolant 22) when a previously determined characteristic temperature T cthe specified maximum temperature T max exceeds; all other settings for the reversing rolling mill corresponding to the second setup values ​​^i remain unchanged. FIG. 3B shows a flow chart for an embodiment of a method according to the invention relating to a feedforward control which determines a characteristic temperature Tc based on a physical model 120. In the following, only the differences to FIG. 3A are discussed. In addition to the maximum temperature T maxAn initial temperature T0 is assumed, which the strip 2 has in the considered rolling pass i immediately before entering the group of rolling stands 10, 11. Then, based on the assumed initial temperature T0 of the strip 2, a temperature distribution ^ (in the sense of a spatial temperature distribution) of the strip 2 is determined using the second setup values ​​^i: this is again done under the assumption of an inactive outlet-side cooling beam 20, 21 (corresponding to the first setup value ^i initially being set to the value 0). In the specific embodiment, the physical model 120 comprises a heat conduction equation for a temperature distribution ^ of the strip 2, wherein the heat conduction equation is solved in a region B for which suitable physical boundary conditions are applied for the considered rolling pass i. Such boundary conditions are described in more detail in FIG. 4.The temperature distribution ^ finally becomes a characteristic temperature T. c of the strip 2 - e.g. a temperature on the underside 2' or on the upper side 2" of the strip 2 - is derived. FIG. 3C shows a flow chart for an embodiment of a method according to the invention relating to online control. Again, only the differences to FIG. 3A will be discussed below. The second setup values ​​^i determined by an offline model are transmitted once before the start of the rolling pass i to the control unit 50. During the rolling pass i, an outlet temperature T i,ex " of belt 2. If the recorded outlet temperature T i,ex " the specified maximum temperature T maxexceeds, a first setup value ^i for the flow rate ^ of coolant 22 through the cooling beam(s) 20, 21 on the outlet side in the considered rolling pass i is determined based on a previously known sensitivity ^, otherwise the first setup value ^i is set to the value 0. The value ^i determined in this way is transmitted to the control unit 50 in each time interval ^t and the outlet temperature T is recorded again. i,ex " in the following time interval. In the specific embodiment of FIG 3C, the first setup value ^i is determined based on the sensitivity ^ such that the sensitivity ^ of the temperature difference from the recorded outlet temperature T i,ex " and the specified maximum temperature. Alternatively, a larger value can be selected for this temperature difference, which allows for a stronger cooling of belt 2 below the maximum temperature T maxFurthermore, in the specific embodiment of FIG 3C, the sensitivity ^ is defined as a functional relationship between the flow rate ^ of coolant 22 through the cooling beam 20, 21, a belt speed v B (specifically the belt run-out speed v i,ex ) and additionally the strip outlet thickness d i,ex known. The belt run-out speed v i,ex and the strip outlet thickness d i,ex are determined for the rolling pass i, for example, by the offline model 100 and are therefore known. At least for the strip run-out speed v i,exHowever, an instantaneous value vi,ex" recorded directly in the relevant time interval ^t can also be used as the argument value of the sensitivity ^ (symbolized by curved brackets in FIG. 3C), which allows a particularly precise determination of the first setup value ^i. FIG. 4 shows a section of a reversing rolling mill 1 to which the method according to the invention relating to forward control is applicable and which comprises only one rolling stand 10 with two work rolls 12, 12' and two backup rolls 18, 18'. For reasons of clarity, only the active inlet-side cooling and lubrication beams 13, 13', 14, 14' are shown, since the corresponding outlet-side cooling and lubrication beams, as in FIG. 1, do not release any coolant or lubricant.Specifically, the boundary conditions of the method according to the invention relating to a feedforward control system, which determines the characteristic temperature Tc using a physical model 120, are explained below. However, these boundary conditions can also be readily applied to a multi-stand reversing rolling mill by a person skilled in the art. 2024P00025 30 From the inlet-side cooling and lubrication beams 13, 13', 14, 14', coolant and lubricant 16 are discharged from the inlet-side cooling and lubrication beams 13, 13', 14, 14' to the work rolls 12, 12' and in the direction of the roll gap, respectively, according to two setup values ​​^i. The cooling and lubricating agent 16 applied by the upper cooling and lubricating beams 13, 14 to the upper work roll 12 or into the roll gap forms a backed-up liquid volume on the upper side 2" of the strip 2, which is diverted in the transverse direction from the strip 2 and extends in the strip running direction over a first effective area W.The coolant and lubricant released from the lower cooling and lubricating beam 13' in the direction of the roll gap only comes into contact with the underside 2' of the strip 2 for a relatively short time due to the effect of gravity and forms a third effective area W" there. In particular, area B, in which a heat conduction equation of the physical model 120 is solved, is indicated in FIG. 4 by means of a dashed rectangle. Area B includes, in addition to a longitudinal section of the strip 2, those areas of the work rolls 12, 12' that are taken into account when solving the heat conduction equation. The strip 2 enters the strip running direction 5 from the right with a strip entry thickness d. i,in into the rolling stand 10 and is rolled to a strip exit thickness d i,ex rolled. By solving the heat conduction equation, a temperature distribution ^of the strip 2 in the thickness direction d Bdetermined, which is indicated at the top left in FIG 4. The heat conduction equation encompasses that section of the strip 2 which begins in the strip travel direction 3 in front of the inlet-side cooling and lubrication beams 13, 13', 14, 14' and ends on the outlet side behind the second effective area W' of the outlet-side cooling beam 20, whereby the cooling beam 20 is assumed to be inactive for the solution of the heat conduction equation. In addition, area B includes the zones of the upper and lower work rolls 12 and 12', shown with thick borders, which only circumscribe a ring-segment-shaped area of ​​the work rolls 12, 12'. 2024P00025 31 When entering region B, a constant temperature T0 is assumed for band 2 as the initial value and boundary condition in the heat conduction equation, which is also shown in Fig. 4 with the identifier 90.Those surface areas of the strip 2 and the work rolls 12, 12' which are in direct contact with the ambient air (including the entire outlet-side underside 2' of the strip 2, since the cooling beam 20 is assumed to be inactive for the solution of the heat conduction equation) are marked with the identifier 91 in FIG. 4: for these areas, a respective corresponding boundary condition in the form of a heat transfer coefficient ^ or ^' corresponding to a laminar or turbulent boundary layer of air as a fluid medium can be applied.Furthermore, the surfaces of the work rolls 12, 12' exposed to coolant and lubricant 16 on the inlet side, as well as the third effective area W" on the underside of the strip, are identified in FIG. 4 with the designator 92: there, the coolant and lubricant 16 forms only a thin liquid film on the respective surface, so that a heat transfer coefficient ^ corresponding to a laminar boundary layer of coolant and lubricant 16 can be applied as a boundary condition in the heat conduction equation. Similarly, a heat transfer coefficient ^' corresponding to a turbulent boundary layer of coolant and lubricant 16 is applied for the contact zone between the backed-up liquid volume of coolant and lubricant 16 and the upper work roll 12 or the upper side 2" of the strip 2 along the first effective area W (designator 93).Heat transfer coefficients ^, ^' for such configurations are known, for example, from formulas (81) to (83) of the aforementioned book by F. Hell (Fundamentals of Heat Transfer). For the contact surfaces between the work rolls 12, 12' and the strip 2, the constant heat flow between the work rolls 12, 12' and the strip 2 is assumed (in addition to source terms due to friction), which is designated 95 2024P00025 32 in FIG. Furthermore, a constant temperature T is assumed as the boundary condition for the inner - hypothetical - edge of the work rolls 12, 12'. W This is a realistic approximation because the temperature T Wcorresponds to the average operating temperature of a work roll during rolling in the reversing rolling mill and can be determined to a good approximation a few minutes after a roll change immediately after a rolling process by measuring the surface temperature of the work roll in question. Finally, thermal insulation is applied as a boundary condition for the radially extending sections of the ring-segment-shaped regions of the work rolls 12, 12' as well as for the interface of the strip 2 emerging from region B (designated 94 in FIG. 4). The described initial value and boundary conditions 90 to 95 uniquely determine the heat conduction equation, and a temperature distribution ^ of the strip can be determined in region B, particularly in the direction of the strip thickness d B , can be determined.

[0002] 2024P00025 33 List of reference symbols R eversierwalzanlage Band bottom, top Band Passlinie5 Strip running direction 10, 11 Rolling stand 12, 12' Work roll 13, 13' Cooling and lubrication beam 14, 14' Cooling and lubrication beam 16 Coolant and lubricant 18, 18' Backup roll 20, 21 Cooling beam 22 Coolant 30, 31, 32 Coiling device 35 Deflection roller 40, 41 Temperature recording device 50 Control unit 51 Data lines 60 Calculation unit 90,..., 95 Boundary condition 100 Offline model 110 Empirical model 120 Physical model a Abstand B Bereich i, i' rolling pass B Strip thickness d i,in Strip inlet thickness d i,ex Strip exit thickness T0Initial temperature T c characteristic temperature Ti,ex" instantaneous outlet temperature T max Maximum temperature T W Roller temperature inside 2024P00025 34 v B Belt speedvB" current belt speedBelt infeed speed current belt infeed speedBelt outfeed speed current belt outfeed speed Effective range^, ^' Heat transfer coefficient^ tTime interval^T Temperature changeFlow rate^ i first setup value, default flow rate^ sensitivity^ i second setup values^ temperature distribution

Claims

2024P00025 35 claims 1. Method for cold rolling a strip (2) in a reversing rolling mill (1) in one or more rolling passes (i), the reversing rolling mill (1) comprising - a group of one or more rolling stands (10, 11), - at least one coiler device (30, 31, 32) for winding and unwinding the strip (2) on each side of the group of rolling stands (10, 11), - at least one cooling and lubricating beam (13, 13', 14, 14') for applying a cooling and lubricating agent (16) on the inlet side on each side of each individual rolling stand (10, 11), and - at least one cooling beam (20, 21) for applying a flow rate (^) of coolant (22) to an underside (2') of the strip (2) to achieve a temperature change (^T) in the strip (2) on at least one side between the group of rolling stands (10, 11) and the coiling device (30, 31, 32), wherein before at least one of the rolling passes (i), in which at least one of the cooling beams (20,21) acts as an outlet-side cooling beam, - initially for the belt (2) a maximum temperature (T, max ) and a first setup value (^ i ) for a flow rate (^) of coolant (22) for all chilled beams (20, 21) is set to a value of 0, - then a characteristic temperature (T c ) of the band (2) is determined and in the case that the characteristic temperature (T c ) the maximum temperature (T max ) - the first setup value (^ i ) for the outlet-side cooling beam(s) (20, 21) on the basis of a sensitivity (^), for which the temperature change (^T) is defined as a functional relationship with at least the flow rate (^) and a strip speed (v B ) is known, 2024P00025 36 and finally the rolling pass (i) is calculated using the first setup value (^ i) for the outlet-side cooling beam(s) (20, 21).

2. Method according to claim 1, wherein the characteristic temperature (T c ) is a temperature value of a strip surface, in particular a bottom side (2') or a top side (2") of the strip (2).

3. Method according to claim 1 or 2, wherein the sensitivity (^) is additionally determined as a functional relationship with a strip thickness (d B ) is known and wherein the setup value ^i is determined according to the relationship ^T =^(^ = ^i; vB; dB).

4. Method according to one of the preceding claims, wherein the characteristic temperature (T c ) is determined on the basis of an empirical model (110) or a physical model (120).

5. The method according to claim 4, wherein - before determining the characteristic temperature (T c) by means of a physical model (120) assuming that the flow rate (^) is zero, based on a given belt runout speed (v i,ex ) and a specified strip outlet thickness (d i,ex ) for the band (2) and using second setup values ​​(^ i ) for the at least one cooling and lubricating beam (13, 13', 14, 14'), starting from an initial temperature (T0) of the strip (2), a temperature distribution (^) of the strip (2) is determined by solving a heat conduction equation of the physical model (120) in a region (B) comprising at least a section of the strip (2), and - then the characteristic temperature (T c ) is determined from the temperature distribution (^).

6. Method according to claim 5, wherein the region (B) extends in the strip running direction at least from the beginning of a first 2024P00025 37 effective range (W) of the first inlet-side cooling and lubricating beam (13, 13', 14, 14') extends at least to the end of a second effective range (W') of the last outlet-side cooling beam (20, 21).

7. Method according to claim 5 or 6, wherein work rolls (12, 12') of the rolling stands (10, 11) are also included in the heat conduction equation.

8. Method according to one of claims 5 to 7, wherein the heat conduction equation is applied as a one-dimensional differential equation and the temperature distribution (^) in the thickness direction of the strip (2) is determined.

9. Method for cold rolling a strip (2) in a reversing rolling mill (1) in one or more rolling passes (i), the reversing rolling mill (1) comprising - a group of one or more rolling stands (10, 11), - at least one coiling device (30, 31, 32) for winding and unwinding the strip (2) on each side of the group of rolling stands (10, 11),- at least one cooling and lubricating beam (13, 13', 14, 14') for applying a cooling and lubricating agent (16) on the inlet side on each side of each individual rolling stand (10, 11), and - at least one cooling beam (20, 21) for applying a flow rate (^) of coolant (22) to an underside (2') of the strip (2) to achieve a temperature change (^T) in the strip (2) on at least one side between the group of rolling stands (10, 11) and the coiling device (30, 31, 32), wherein before at least one of the rolling passes (i), in which at least one of the cooling beams (20, 21) acts as an outlet-side cooling beam, - a maximum temperature (T, max ) is specified for the strip (2) and during the rolling pass (i) cyclically in time intervals (^ t ) respectively 2024P00025 38 - by means of a temperature detection device (40, 41) an outlet temperature (T i,ex") of the belt (2) is detected and in the event that the outlet temperature (T i,ex ") the maximum temperature (T max ), - a first setup value (^ i ) for the outlet-side cooling beam(s) (20, 21) on the basis of a sensitivity (^), for which the temperature change (^T) is defined as a functional relationship with at least the flow rate (^) and a strip speed (v B ) is known, and - then the first setup value (^ i ) is specified for the outlet-side cooling beam(s) (20, 21).

10. Method according to claim 9, wherein in the time intervals (^ t ) a current belt speed (v B ") as the known belt speed (v B ) is detected.

11. Method according to claim 9 or 10, wherein the sensitivity (^) is additionally determined as a functional relationship with a strip thickness (d B) is known and wherein the first setup value (^i) is determined according to the relationship ^T =^(^ = ^i; vB; dB).

12. Method according to one of claims 9 to 12, wherein the temperature detection device (40, 41) is arranged at a distance (a) behind the end of a second effective range (W') of the last outlet-side cooling beam (20, 21).

13. Method according to one of claims 9 to 12, wherein the time intervals (^ t ) have an interval duration of a maximum of 10ms.

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