Method for determining improved setup values for a roll stand for cold rolling a strip

Abstract

Prior to a rolling pass (i) of a strip (100) in a rolling stand (10), characterized by a parameter set (Λi), a minimum and maximum temperature (Tmin, Tmax), a minimum and maximum coefficient of friction (µmin, µmax), and limit values ​​(Emin, Emax) for an emulsion actuator (21,...,23') as well as setup values ​​for the emulsion actuator (21,...,23'), a cooling actuator (41,...,42'), and a lubrication actuator (31,...,32') are specified by a setup model (200). During the rolling pass (i), the actuators are set to the setup values. Using a temperature sensing device (51, 52), an actual strip temperature (T') and an actual coefficient of friction (u') are determined from the measured actual values ​​of the manipulated variables (M'). Depending on this, improved setup values ​​are applied either only to the cooling actuator (41,...,42') or the lubrication actuator (31,...,32'), or, if there is a change in the applied coolant rate or...The lubricant rate behaves synergistically with respect to the emulsion rate and is also determined for the emulsion actuator (21,...,23'). The improved setup values ​​are transferred from the setup model (200) to the parameter set (Λi).

Description

[0001] The invention relates to a method for determining improved setup values ​​for a rolling mill stand comprising at least one emulsion actuator and at least one lubrication actuator, and to which at least one cooling actuator is assigned.

[0002] In a cold rolling mill, when producing flat metallic rolled products, referred to simply as "strips," several parameters play a crucial role in ensuring consistent quality. These parameters, in addition to the so-called pass schedule (which defines the successive thickness reduction of a strip as it passes through the individual rolling stands), are essential. Since a cold rolling mill can be pushed to its limits when producing strips from modern steel grades, it is imperative to consider critical parameters such as varying friction conditions or the temperature of the strips in each rolling pass. Appropriate measures for stable process control must be implemented, as these parameters change dynamically during the rolling process and significantly influence the power and energy requirements of the cold rolling mill, as well as the feasibility of the intended pass schedule.

[0003] For example, the friction between a roll and a strip within a pass plan can vary so significantly that the coefficient of friction µ rises above a critical value, leading to increased rolling force requirements in individual passes and negatively impacting the rollability of the strip. In other cases, the friction between the work rolls and the strip may be too low, resulting in the strip slipping in the roll gap and making controlled process management impossible.

[0004] In this context, a method for rolling a rolled material is known from EP 3 448 592 B1, wherein a cooling lubricant in the form of an emulsion is introduced into a contact zone between the rolled material and a work roll. At a predetermined application distance in front of the roll gap, an additional lubricant is applied to the rolled material if the amount of cooling lubricant currently introduced into the contact zone does not cover the lubrication requirements, whereby the amount of cooling lubricant introduced into the contact zone is simultaneously reduced.

[0005] Furthermore, the temperature of a strip may be too low at the beginning of a cold rolling cycle, which leads to difficult forming, while at the end of the cold rolling cycle the temperature may be too high, causing problems with product quality or the further processing of the strip.

[0006] In this regard, WO 2021 / 048038 A1 discloses the method of specifying a temperature window for the rolled material during cold rolling in a rolling mill with multiple stands and ensuring, through various control measures, that the rolled material temperature remains within this temperature window during rolling. These measures include heating the rolled material before a rolling pass, cooling and lubricating the work rolls or the rolled material itself using appropriate cooling and lubrication bars, creating a suitable pass schedule to account for the heat of deformation generated during rolling, and controlling the rolling speed to account for the frictional power losses in a rolling stand. The effect of these control measures on the rolled material temperature can be determined in advance, either based on empirical data in the form of an empirical model or using a physical model.Before the actual rolling process, simulations are performed and the setup values ​​for the respective components of the cold rolling mill are adjusted accordingly. Furthermore, the temperature of the rolled material can be measured during rolling, and control measures can be adjusted online.

[0007] Furthermore, stable process control with regard to the aforementioned dynamically changing process parameters can be achieved by selecting a suitable operating mode for the components installed in the cold rolling mill, for example, in the form of appropriate cooling, lubrication, and rolling strategies. The temperature of a strip can be influenced by an operator, for instance, by specifying suitable rolling speeds and selecting an appropriate pass schedule. Lubrication can be adapted by using appropriately ground rolls and by adjusting the operating parameters of the lubrication system (e.g., oil concentration). However, all these operational optimizations are time-consuming and require extensive upstream and downstream analyses, since a change in one parameter of a single component usually affects other components as well.For example, changes in the lubrication system may have a positive effect on process control, but at the same time have negative consequences for quality (e.g., strip cleanliness).

[0008] It is therefore an object of the invention to keep process variables that vary between the individual passes of a strip in a rolling stand mentioned above, in particular the friction conditions in the roll gap and the temperature of the strips, under control to such an extent that a planned pass plan is feasible and the product quality is within specified tolerance limits.

[0009] Another object of the invention is to make the best possible use of the operating mode of the components present in a rolling mill mentioned above, within their limits, in order to achieve the broadest possible product range.

[0010] These problems are solved according to the invention by a method according to claim 1, wherein the emulsion, cooling, and lubrication actuators of the rolling mill stand are considered simultaneously. Preferred embodiments of the method according to the invention are the subject of the dependent method claims.

[0011] The inventive method for determining improved setup values ​​relates to the cold rolling of a strip in a rolling stand in one or more passes. The rolling stand can be part of a multi-stand cold rolling mill in which the strip is fed through the multiple stands in a specific strip direction (so-called tandem mill). Alternatively, the rolling stand can also be part of a single- or multi-stand reversing rolling mill in which the strip is fed through the one or more stands in alternating strip directions during cold rolling.

[0012] Each passage of the strip through the rolling stand under consideration is referred to as a rolling pass i, whereby the thickness of the strip is usually reduced and the strip is guided through a roll gap formed by two work rolls that the rolling stand has.

[0013] The rolling stand includes an emulsion actuator for dispensing emulsion onto the work rolls and / or into the roll gap. Furthermore, the rolling stand includes a lubrication actuator configured to dispense lubricant onto the strip and / or the work rolls. The rate of lubricant dispensed by the lubrication actuator is controllable within a range between a minimum lubricant rate Lmin and a maximum lubricant rate Lmax. The rolling stand may also include additional emulsion actuators and / or lubrication actuators, the respective setup values ​​of which are not modified within the scope of the present invention and are therefore not considered separately below.

[0014] Furthermore, a cooling actuator is assigned to the rolling stand, designed to discharge coolant onto the strip. The rate of coolant discharge by the cooling actuator is controllable within a range between a minimum coolant rate Cmin and a maximum coolant rate Cmax. In this context, the term 'assigned to the rolling stand' does not necessarily mean that the cooling actuator—unlike the respective emulsion or lubrication actuator of the rolling stand—is functionally connected to only that one rolling stand; rather, an 'assigned' cooling actuator can simultaneously be a functional component of several rolling stands.For example, a single cooling actuator can be assigned to and positioned between the two rolling stands of a double reversing rolling mill, so that with each rolling pass on such a mill, the cooling actuator simultaneously acts as both an exit-side and an entry-side cooling actuator for one of the rolling stands. Furthermore, additional cooling actuators can be assigned to the rolling stand, but their respective setup values ​​are not changed within the scope of the present invention.

[0015] The emulsion, lubrication, and cooling actuators can, in typical technical terms, be spray bars extending essentially transversely to the belt direction for dispensing a liquid medium. These spray bars are equipped, for example, with single- or two-component nozzles, and their dispensing rates of liquid medium are adjustable by means of corresponding valves. Furthermore, within the scope of the invention, each emulsion, lubrication, or cooling actuator can comprise several active elements (e.g., one or more upper and / or lower spray bars) that are controlled together, such that the dispensed fluid rate is equal to the sum of the rates of the individual spray bars. Likewise, the respective minimum and maximum rates refer to the sum of all individual elements of an actuator.

[0016] The emulsion according to the invention is a mixture of two main components: water (as the primary cooling medium) and pure oil (as the lubricating medium). The oil content in the water is between 0% and 30%, and the oil is optionally chemically stabilized in the water by means of an emulsifier. Due to its application point and its two main components, the emulsion released by the emulsion actuators during a rolling pass has a cooling effect and also adjusts the friction conditions in the roll gap accordingly. Consequently, increasing or decreasing the amount of emulsion applied during a rolling pass reduces or increases the temperature of the strip or the work rolls and also decreases or increases the coefficient of friction µ' between the strip surface and the work rolls.

[0017] Preferably, the lubricant is applied by the lubrication actuator (considered within the scope of the invention) to the strip at a specific first application distance d1 upstream of the roll gap, or directly to the work rolls of the respective rolling stand at the entry side. It is essential that the lubricant is not applied to the same location on the strip or work rolls simultaneously with the emulsion or coolant, in order to prevent immediate washing off of the lubricant from the relevant surface. Similar to emulsion actuators, the lubrication actuators can be designed as beams with single- or two-component nozzles and, due to the composition of the lubricant and the significantly lower application rate compared to emulsion and cooling actuators, essentially produce a pure lubrication effect with a negligible cooling effect.

[0018] Preferably, the coolant is applied directly to the strip by the cooling actuator (considered within the scope of the invention) either before or after the respective rolling stand; it is essential that the coolant is applied to the strip spatially separated from the emulsion or lubricant. On the entry side, the coolant is applied at a specific second application distance d2, which is preferably larger than the first application distance d1 for the lubricant, in front of the roll gap, so that up to the point where a lubricant or emulsion is optionally applied to the strip, the majority of the coolant flows off the strip laterally and does not affect the effect of the applied emulsion or lubricant. Within the roll gap itself, the strip typically experiences heating due to the forming process, but this has no effect on the metallurgical structure of the strip during cold rolling.Therefore, alternatively, the coolant can be applied by the cooling actuator (considered within the scope of the invention) at a specific third application distance ds behind the roll gap on the exit side, in order not to influence any exit-side cooling of the work rolls by the emulsion actuators, whereby a brief exceedance of the maximum strip temperature T max behind the roll gap can be tolerated. Due to the spatial application and the significantly lower oil content compared to the lubricant, the cooling actuator essentially provides a purely cooling effect on the strip in front of or behind the roll gap.

[0019] Each rolling pass i of the strip in the rolling stand is characterized by a specific set of parameters Λi. For rolling pass i, the parameter set Λi includes, for example, a thickness range Di of the strip, a pass reduction range Ri, a strip speed range Vi, and at least one material quality range Qi. The thickness range Di and the strip speed range Vi can each be entry- or exit-related ranges for the respective dimensions when entering or exiting the rolling stand. The pass reduction range Ri (e.g., 60 to 65 percent) can be a specific percentage by which the strip is reduced in thickness during rolling pass i. The material quality range Qi can be a range for a specific material property of the strip (e.g., tensile strength), for the percentage by weight of a specific impurity (e.g.,carbon) in the strip or for the relative proportion of a particular metallurgical phase.

[0020] Each parameter from the parameter set Λ i lies, by definition, in exactly one predefined range, so that the rolling mill i (within the respective predefined parameter ranges) can be uniquely described using the parameter set Λ i. Furthermore, a rolling mill i can thus be represented particularly easily – for example, in the form of a table for the individual parameter ranges.

[0021] In the inventive method, in a first step S1, a minimum temperature Tmin and a maximum temperature Tmax, as well as a minimum coefficient of friction µmin and a maximum coefficient of friction µmax, are specified for the strip before each rolling pass i. Furthermore, in the first step S1, an emulsion setup value SE, a lower emulsion limit Emin, and an upper emulsion limit Emax are specified by a setup model for the emulsion actuator, a lubricant setup value SL for the lubrication actuator, and a coolant setup value Sc for the cooling actuator. Again, the setup values ​​SE, SL, and Sc refer to the total rate of all elements of the respective actuator. In contrast to the minimum / maximum coolant rate Cmin / Cmax, respectively, the setup values ​​SE, SL, and Sc are not defined by a single, fixed value.The minimum / maximum lubricant rate Lmin / Lmax, which characterize the technically possible adjustment range of the respective actuator itself, are contrasted with the lower / upper emulsion limit values ​​Emin / Emax, which are adjustment range limits predefined by the setup model within which a desired rolling result can be expected. Assuming that the lower and upper emulsion limit values ​​Emin and Emax lie within the technically possible adjustment limits of the emulsion actuator, which are known to the setup model, respectively, the setup model assumes.

[0022] The aforementioned setup models are known from the state of the art; these can further include target values ​​for the drives of a rolling mill stand with regard to thickness reduction or an entry-side and exit-side rolling speed in a single pass i. Such a setup model is aware of the technological limits of the respective cold rolling mill or the rolling mill stand in question, such as maximum possible rolling forces, strip speeds, the minimum and maximum lubricant rates Lmin and Lmax of the lubrication actuators, as well as the minimum and maximum coolant rates Cmin and Cmax of the cooling actuators, etc. However, such setup models do not determine the temperature or temperature changes of the strip, for example, due to its cooling and deformation during the rolling process.

[0023] In a second step S2 of the inventive method, the strip is guided through the roll gap during each rolling pass i. Furthermore, in the second step S2, the emulsion actuator is set to the emulsion setup value SE, the lubrication actuator to the lubricant setup value SL, and the cooling actuator to the coolant setup value SC, which is done, for example, by transmitting corresponding control signals from a plant control system to the individual actuators.

[0024] Furthermore, in the second step S2, the actual strip temperature T' of the strip is determined using a temperature sensing device. In the context of the invention, an 'actual value' is understood to mean a measured quantity recorded during the execution of a rolling pass i or a measured quantity derived from recorded values. In contrast, setup values ​​represent control variables that are defined before the execution of a rolling pass i.

[0025] The temperature sensing device can, for example, be designed as a pyrometer arranged at the entry or exit end of the rolling stand, which advantageously enables non-contact measurement of the strip's surface temperature distribution. From this, an actual strip temperature T' can be determined – for example, by statistical averaging over a specific surface area of ​​the strip. Such statistical averaging over a surface area of ​​the strip, for example, over a region perpendicular to the strip's direction of travel, advantageously allows for a particularly accurate determination of the actual strip temperature at its surface, because erroneous values ​​that distort the result – for example, emulsion or coolant residues on the strip surface – can be largely eliminated when determining the actual strip temperature T' using statistical methods. Such a method, or rather,However, such statistical averaging itself is not the subject of the invention.

[0026] Measuring the actual strip temperature T' provides a particularly reliable value for the strip surface temperature compared to a model-based determination, because during cold rolling, only very small residues of applied coolant or lubricant remain on the strip, which generally do not significantly distort the measurement result. In this context, the minimum temperature Tmin, together with the maximum temperature Tmax, defines a temperature range within which a satisfactory rolling result for the strip is expected in the considered rolling pass i. The minimum temperature Tmin and the maximum temperature Tmax can, for example, be selected based on empirical values ​​depending on the material composition of the strip, with the minimum temperature Tmin preferably in the range of 50°C to 70°C and the maximum temperature Tmax preferably in the range of 120°C to 160°C.

[0027] Furthermore, in the second step S2, one or more actual control variable values ​​M' of the rolling stand, preferably including at least one actual rolling force F', are recorded. The control variables for the rolling stand are specified for each relevant rolling pass i by a control system for the individual sections, whereby actual values ​​– such as the applied actual rolling force F' – can be read by a basic automation system of the rolling mill during the rolling pass i using respective sensors. From the recorded actual control variable values ​​M', an actual friction coefficient u', which characterizes the friction conditions in the roll gap during the rolling pass i, is determined, for example, using a roll gap model. Such roll gap models are known from the prior art, for example from DR Bland, H. Ford, et al., The Calculation of Roll Force and Torque in Cold Strip Rolling with Tensions, Proceedings of the Institution of Mechanical Engineers, Vol. 159, 1948, or from E.Orowan, The calculation of Roll Pressure in Hot and Cold Flat Rolling, Proceedings of the Institution of mechanical engineers, Vol. 150, pp. 140-167, 1948.

[0028] In a preferred embodiment of the method according to the invention, the measured actual values ​​M' of the control variables include, in addition to the actual rolling force F', an actual lead δ' and / or an actual drive torque Γ' of the work rolls. The actual lead δ' is defined as the ratio of the speed difference between the exit-side strip speed and the roll speed with respect to the roll speed itself. By additionally considering the actual lead δ' and / or the actual drive torque Γ' of the work rolls alongside the actual rolling force F', the actual coefficient of friction µ' can be determined advantageously with particularly high accuracy.

[0029] In a third step S3 of the method according to the invention, in a scenario A in which either the actual strip temperature T' is greater than the maximum temperature Tmax and the actual coefficient of friction µ' is less than the minimum coefficient of friction µmin, or in which the actual strip temperature T' is less than the minimum temperature Tmin and the actual coefficient of friction µ' is greater than the maximum coefficient of friction µmax, an improved coolant setup value Sc' and an improved lubricant setup value SL' are determined. Subsequently, the improved coolant setup value Sc' and the improved lubricant setup value SL' determined in this way are adopted for the parameter set Λi from the aforementioned setup model.

[0030] Scenario A describes a situation in which a change in the emulsion rate delivered by the emulsion actuator of the rolling stand would have an opposing effect on the actual strip temperature T' and the actual coefficient of friction µ': an increase in the emulsion rate would advantageously lower the strip temperature, but would also further decrease the coefficient of friction in the roll gap. Conversely, a decrease in the emulsion rate would advantageously increase the coefficient of friction, but would also adversely increase the strip temperature even further. Therefore, according to the invention, no new emulsion setup value SE' is determined in Scenario A; instead, only the actual strip temperature T' is influenced within the control range of the cooling actuator, and the actual coefficient of friction µ' within the control range of the lubrication actuator.Within the scope of the invention, the operating range of an actuator is defined as the range between a minimum and a maximum possible delivery rate of fluid by the respective actuator. In particular, the minimum delivery rate of an actuator can be zero.

[0031] In scenario A described above, the improved coolant setup value SC ' and the improved lubricant setup value SL ' determined according to the invention also lead to an advantageous influence on the actual strip temperature T' and the actual coefficient of friction µ' in a subsequent rolling pass, which is carried out with the same parameters Λ i as the considered rolling pass i, because the lubrication and cooling actuators are arranged relative to the rolling stand in such a way that they do not influence each other in their respective mode of operation.

[0032] In scenario B, where either the actual strip temperature T' is greater than the maximum temperature Tmax and / or the actual coefficient of friction µ' is greater than the maximum coefficient of friction µmax, or where the actual strip temperature T' is less than the minimum temperature Tmin and / or the actual coefficient of friction µ' is less than the minimum coefficient of friction µmin, an improved coolant setup value Sc' and / or an improved lubricant setup value SL' and / or an improved emulsion setup value SE' are determined in the third step S3 and adopted from the aforementioned setup model for the parameter set Λi. The improved emulsion setup value SE' is defined as a value greater than or equal to the lower emulsion limit Emin and less than or equal to the upper emulsion limit Emax.

[0033] Scenario B, in contrast to Scenario A, describes a situation in which a change in the emulsion delivered by the emulsion actuator has a synergistic effect on the determined actual strip temperature T' or the actual coefficient of friction µ': if the actual strip temperature T' or the actual coefficient of friction µ' is too high, increasing the amount of emulsion advantageously lowers both the strip temperature and the excessively high coefficient of friction in the roll gap. Conversely, reducing the amount of emulsion in the case of an excessively low strip temperature or coefficient of friction advantageously increases both the strip temperature and the coefficient of friction. Therefore, according to the invention, in Scenario B, in addition to the improved coolant setup value Sc' and / or the improved lubricant setup value SL', an improved emulsion setup value SE' is optionally also determined.

[0034] In the described scenario B, in addition to the adjustment ranges of the cooling actuator(s) and the lubrication actuator(s), the adjustment range of the emulsion actuator is also used to improve the strip temperature and the coefficient of friction in the roll gap, which represents an advantageous utilization of the components available on a rolling stand compared to the prior art, because such constellations, in which lubrication and cooling actuators work synergistically with an emulsion actuator, are not captured by conventional setup models.

[0035] In summary, the method according to the invention, when determining improved setup values ​​for the cooling, lubrication, and emulsion actuators, utilizes the tolerances defined by the adjustment ranges of the cooling and lubrication actuators or by the lower and upper emulsion limit values ​​E min and E max, respectively, without changing the throughput of rolled strips at the rolling stand or cold rolling mill, because rolling speeds or pass schedules are not altered. The improved setup values ​​determined according to the invention can be used as new setup values ​​for subsequent rolling passes characterized by the same parameter set Λ i as the rolling pass from which the improved setup values ​​were derived. In these subsequent rolling passes, it is advantageously less frequent to encounter deviations from either the minimum or maximum temperature T min or T max, or from the minimum or maximum coefficient of friction µ min or T max.µ max can be calculated.

[0036] Because the inventive method only modifies the setup values ​​for the cooling, lubrication, and, if applicable, the emulsion actuator (within the predefined limits E min and E max) and adopts them from an existing setup model, but not the other setup or default values ​​for the remaining components of the cold rolling mill, the process parameters lubrication, cooling, and temperature can be decoupled from the conventional core parameters, such as the rolling strategy and the effect of the rolling emulsion. This allows the inventive method to be advantageously implemented retroactively on an existing cold rolling mill with minimal effort, without requiring any changes to the roll planning or the roll gap model itself. In particular, the operation of an existing setup model, which already knows the technological limits of the mill, does not need to be modified.

[0037] In a preferred embodiment of the method according to the invention, the improved coolant setup value Sc' in the scenario A described above is averaged, using a first sensitivity σ1, as a value that lies between the minimum and maximum coolant rates Cmin and Cmax of the cooling actuator. Furthermore, the improved lubricant setup value SL' is determined, using a second sensitivity σ2, as a value that lies between the minimum and maximum lubricant rates Lmin and Lmax of the lubricating actuator.

[0038] The first sensitivity σ1 describes the change in the actual strip temperature T' resulting from the application of coolant and depends on the coolant flow rate ΦC set at the cooling actuator (specifically: the amount of coolant delivered per strip surface, e.g., in liters per square meter) and on the strip thickness d in the considered rolling pass i. Similarly, the second sensitivity σ2 describes the change in the actual coefficient of friction Δµ' in the roll gap as a function of the lubricant flow rate ΦL set at the lubrication actuator (specifically: the amount of lubricant delivered per strip surface, e.g., in milliliters per square meter). The amount delivered per strip surface by the cooling or lubrication actuator can be easily calculated from the strip speed vB at which the strip passes the respective actuator, the strip width b, and the flow rate of the cooling or lubrication actuator (which is determined, for example, by...).The strip speed (vB) and the strip width (b) can be determined (in liters per second or milliliters per second). The strip speed vB and the strip width b can be obtained, for example, from the data of the setup model or from a corresponding basic automation system of the rolling mill.

[0039] According to the invention, the sensitivities σ1 and σ2 are assumed to be known functional relationships, which, for example, can be determined empirically beforehand as a function between an observed change in the actual temperature T' or the actual coefficient of friction µ' and the set flow rate ΦC or ΦL at the cooling or lubrication actuator. Knowing such relationships, the improved coolant setup value SC' or the improved lubricant setup value SL' in scenario A can be set independently of each other to a desired target value because – as described above – the lubrication actuator and the cooling actuator are arranged in relation to the rolling mill in such a way that their respective effects do not influence each other.

[0040] In a further preferred embodiment of the method according to the invention, in scenario B described above, a first correction value Δ1 and a second correction value Δ2 are each initially set to zero. If the actual strip temperature T' is greater than the maximum temperature Tmax or less than the minimum temperature Tmin, the improved coolant setup value Sc' is determined based on the aforementioned first sensitivity σ1.

[0041] If the determined improved coolant setup value Sc' is less than the minimum coolant rate C min, the improved coolant setup value SC' is set to the value of the minimum coolant rate C min to comply with the technological limits of the coolant actuator in question. Similarly, if the improved coolant setup value SC' is determined to be greater than the maximum coolant rate C max, it is subsequently set to the maximum coolant rate C max. In both of these cases, the first correction value Δ1 is also recalculated using a third sensitivity σ3.

[0042] The third sensitivity σ3 describes – analogous to the first and second sensitivities σ1 and σ2 – the change in the actual strip temperature T' as a function of a change in the emulsion flow rate ΔΦ E delivered by the emulsion actuator (specifically: the change in the amount of emulsion delivered per strip surface, e.g. in liters per square meter) relative to the emulsion setup value SE set (according to the setup model) and is assumed to be known according to the invention.

[0043] Furthermore, according to the preferred embodiment in scenario B, if the actual coefficient of friction µ' is greater than the maximum coefficient of friction µmax or less than the minimum coefficient of friction µmin, the improved lubricant setup value SL' is determined based on the aforementioned second sensitivity σ2. Again, analogous to the determination of the improved coolant setup value SC', the improved lubricant setup value SL' is limited to the minimum or maximum lubricant rate Lmin or Lmax, respectively, in order to comply with the technological limits of the lubricant actuator(s).In addition, in these cases the second correction value Δ 2 is again determined using a fourth sensitivity σ4, wherein the fourth sensitivity σ4 - analogous to the third sensitivity σ3 - describes the change in the actual coefficient of friction Δµ' as a function of the change in the emulsion flow ΔΦ E from the emulsion actuator (again relative to the set emulsion setup value SE ) and is assumed to be known according to the invention.

[0044] Subsequently, if the first and / or the second correction value Δ1 and Δ2 are not equal to zero (meaning that the cooling actuator and the lubrication actuator, respectively, should be 'adjusted' for a future rolling pass because the improved setup value SC' and SL' has been determined to be identical to the respective minimum or maximum cooling or lubricant rate Cmin, Cmax, and Lmin, respectively), a sum Σ = SE + Δ1 + Δ2 is calculated according to the further preferred embodiment in scenario B from the emulsion setup value SE already specified by the setup model and the first and second correction values ​​Δ1 and Δ2. Conversely, if both the first and second correction values ​​Δ1 and Δ2 are zero, this means that the cooling and lubrication actuators do not need to be adjusted (in the sense described above) in subsequent rolling passes. Therefore, no improved setup value SE' is determined in this case.

[0045] If the sum Σ is determined (i.e., both Δ1 and Δ2 are non-zero) and is less than (mathematically speaking, in the sense of real numbers) the lower emulsion limit Emin, the improved emulsion setup value SE' is ultimately set equal to the lower emulsion limit Emin to ensure that the emulsion rate applied does not fall below the range specified by the setup model. Similarly, if the sum Σ is greater than the upper emulsion limit Emax, the improved emulsion setup value SE' is set equal to the upper emulsion limit Emax. In all other cases, i.e., if the sum Σ is greater than or equal to the lower emulsion limit Emin and less than or equal to the upper emulsion limit Emax, the improved emulsion setup value SE' is set equal to the sum Σ itself.

[0046] In simplified terms, scenario B, according to the further preferred embodiment, improved setup values ​​for the cooling actuator and / or the lubrication actuator are first determined. If it turns out that the respective actuator is being 'controlled out' (i.e., set to the minimum or maximum technically possible flow rate), additional correction values ​​Δ1 and Δ2 are subsequently determined for the emulsion actuator, since this (as described above) influences both the actual strip temperature T' and the actual coefficient of friction µ'. The correction values ​​Δ1 and Δ2 can also take on negative values ​​(which corresponds to a corresponding reduction in the amount of emulsion delivered) and are added to the predefined emulsion setup value SE. The result is, if necessary, limited to the range between the lower and upper emulsion limits E min and E max and forms the improved emulsion setup value SE'.Since scenario B – as described above – represents the synergistic case between the cooling and lubrication actuator on the one hand and the emulsion actuator on the other, the emulsion actuator is also used within its predefined control limits E min and E max when the cooling and / or lubrication actuator is 'adjusted'. In this way, all available components of the rolling mill in question are optimally utilized within their respective limits to advantageously influence the actual strip temperature T' or the actual coefficient of friction µ' (or both simultaneously).

[0047] Preferably, the lubricant dispensed by the lubrication actuator onto the strip and / or the work rolls during a rolling pass i contains at least 80% pure oil. Similarly, the coolant dispensed by the cooling actuator onto the strip preferably contains at least 80% water; for example, it could be an emulsion of water and oil. Furthermore, preferably the same emulsion used for the emulsion actuator can be used, thus advantageously eliminating the need for a separate media circuit for the coolant.

[0048] The properties, features, and advantages of this invention described above, as well as the manner in which they are achieved, will become clearer and more readily understandable in connection with the following description of an exemplary embodiment, which is explained in more detail in conjunction with the figures. These figures show: Figur 1 (FIG 1 ) an embodiment of a rolling mill stand with emulsion, lubrication and cooling actuators to which the method according to the invention is applicable; Figur 2 (FIG 2 ) a basic flowchart of the inventive process; Figur 3A (FIG 3A ) an embodiment for determining improved setup values ​​according to scenario A of the inventive method; Figur 3B (FIG 3B ) an alternative embodiment for determining improved setup values ​​according to scenario A of the inventive method; Figur 4A (FIG 4A ) an embodiment for determining improved setup values ​​according to scenario B of the inventive method; and Figur 4B (FIG 4B ) an alternative embodiment for determining improved setup values ​​according to scenario B of the inventive method.

[0049] Corresponding parts are marked with the same reference symbols in the figures.

[0050] FIG 1 Figure 1 shows a rolling stand 10 with an upper work roll 11 and a lower work roll 11', which form the roll gap 12. A strip 100 is guided through the roll gap 12 from right to left in the strip travel direction 14 in the depicted rolling pass i. The direction of rotation of the lower work roll 11' in the depicted rolling pass i is indicated by an arrow pointing counterclockwise. Furthermore, in FIG 1 An upper intermediate or support roll 13 is indicated above the upper work roll 11 and a lower intermediate or support roll 13' is indicated below the lower work roll 11'.

[0051] In FIG 1 The solid lines represent the emulsion spray bars of the rolling stand 10 that are activated in the depicted rolling pass i: these include, on the entry side, the emulsion spray bars 21 and 21', which apply an emulsion 20 (solid lines) directly onto the upper and lower work rolls 11 and 11', respectively. Also shown on the entry side are the emulsion spray bars 23 and 23', which apply emulsion 20 from above and below the strip 100 into the roll gap 12, respectively. Additionally, the exit side shows the emulsion spray bars 22 and 22', which apply the emulsion 20 directly onto the upper and lower work rolls 11 and 11', respectively. Any further emulsion spray bars that are inactive in the depicted rolling pass i, for example, when the strip direction changes, are not shown. FIG 1 The emulsion 20 would be applied from the left into the roller gap 12, are shown for clarity in FIG 1 not shown.

[0052] The inlet-side emulsion spray bars 21, 21', 23, 23' and the outlet-side emulsion spray bars 22, 22' form the emulsion actuator of the rolling stand 10 in the sense described above, i.e. they are controlled together and an improved emulsion setup value SE ' is determined.

[0053] Furthermore, in FIG 1 The dotted lines represent the lubricant spray bars of the rolling stand 10 that are activated during rolling pass i. Any other inactive lubrication actuators that are not activated during rolling pass i are not shown. Pure lubricant 30 (dotted lines) is atomized as a fine aerosol, for example, using compressed air and two-component nozzles, or dispensed using so-called single-component nozzles. On the entry side, an upper and a lower lubricant spray bar 31 and 31', respectively, apply the lubricant 30 directly to the upper and lower work rolls 11 and 11', respectively. Furthermore, an upper and a lower lubricant spray bar 32 and 32' apply lubricant 30 at a first application distance d 1 to the roll gap 12 onto the upper and lower sides of the strip 100, respectively.

[0054] In the FIG 1 In the illustrated embodiment, the lubricant spray bars 32 and 32' directed towards the strip 10 constitute the lubrication actuator of the rolling stand 10 within the scope of the invention. The lubricant spray bars 32 and 32' are controlled together, and an improved lubricant setup value SL' is determined for them. In contrast, during the rolling pass i, the lubricant spray bars 31 and 31' are active, but no improved setup value is determined for them (i.e., their delivery rate is determined otherwise, e.g., by a setup model 200). Alternatively, the lubricant spray bars 31 and 31' directed towards the work rolls 11, 11' can also constitute the lubrication actuator of the rolling stand within the meaning of the invention, while in this case, no improved setup values ​​are determined for the lubricant spray bars 32 and 32'.

[0055] Furthermore, temperature sensing devices 51 and 52, respectively, are arranged above the strip 100 on the inlet and outlet sides of the rolling stand 10. These devices are designed as pyrometers and allow for the measurement of the instantaneous distribution of the strip surface temperature in a direction transverse to the strip travel direction 14. An arrangement above the strip 100—in contrast to an arrangement below it—offers the advantage that no contamination occurs from residual emulsion 20 or coolant 40 dripping from the strip 100. Any residual emulsion 20 or coolant 40 remaining on the top surface of the strip 100 can therefore be detected particularly easily due to the significantly reduced surface temperature of the strip at these points, thus enabling a reliable determination of the actual strip temperature T'.

[0056] Finally, in FIG 1 The coolant spray bars associated with the rolling stand 10 are shown with dashed lines: on the entry side, coolant 40 (dashed lines) is applied directly to the top and bottom surfaces of the strip 100 by an upper and lower cooling actuator 41 and 41', respectively. The coolant spray bars 41 and 41' are arranged at a second application distance d2, which is greater than the first application distance d1, from the roll gap 12. On the exit side, the coolant 40 can be discharged directly onto the top and bottom surfaces of the strip 100 by an upper and lower coolant spray bar 42 and 42', respectively, arranged at a third application distance ds from the roll gap 12.

[0057] In the FIG 1 In the illustrated embodiment, the exit-side coolant spray bars 42 and 42' for rolling pass i constitute the cooling actuator of the rolling stand 10 within the scope of the invention; accordingly, the coolant spray bars 42 and 42' are controlled together, and an improved coolant setup value SC' is determined based on the actual strip temperature T' of the strip 100, wherein the actual strip temperature T' is determined based on measured values ​​from the exit-side pyrometer 52. In contrast, the delivery rates for the inlet-side coolant spray bars 41, 41' in rolling pass i are otherwise specified or set to zero, and no improved setup values ​​are determined for the coolant spray bars 41, 41' (in rolling pass i).

[0058] Alternatively, in rolling section i, the inlet-side coolant spray bars 41 and 41' can also form the cooling actuator assigned to the rolling stand 10, in which case an improved coolant setup value SC' is determined for these, and the actual strip temperature T' is determined based on measured values ​​from the inlet-side pyrometer 51. The discharge rates of the outlet-side coolant spray bars 42, 42' in rolling section i are then determined differently in this case.

[0059] In FIG 2 The steps S1, S2, and S3 of the inventive method are schematically indicated on the right and separated from each other by means of dashed lines, the method relating to a specific rolling pass i of a specific strip 100 on a specific rolling stand 10 of a cold rolling mill. (Right in) FIG 2 The index i indicates that the rolling pass i is performed in the second process step S2. In the illustrated embodiment, steps S1 to S3 are executed on a separate computing unit 70, which is connected to a basic automation system 60 of the respective cold rolling mill. This transmits the relevant actual data for the rolling stand 10 – such as the actual strip temperature T' and the emulsion, lubricant, or coolant setup values ​​SE, SL, or SC – to the computing unit 70. Furthermore, a connection to a higher-level control system and / or an operator interface (in FIG 2 (not shown) corresponding target data - such as the minimum or maximum temperature T min or T max, the minimum or maximum coefficient of friction µ min or µ max and the parameter set Λ i - are transmitted to the computing unit 70.

[0060] The parameter set Λ i, which uniquely characterizes the rolling pass i for the strip 100, includes, for example, a thickness range D i of the strip, a strip speed range V i, a pass reduction range R i, and at least one material quality range Q i. These ranges are known in advance to a setup model 200 because it also specifies the concrete target values ​​for the rolling pass i – such as a target rolling force, a target pass reduction, an entry or exit speed, and an entry or exit thickness into or out of the rolling stand 10.

[0061] In the first step S1, which is executed before the actual rolling pass i under consideration, the setup model 200 specifies the emulsion setup value SE for the emulsion actuator 21,...,23' and the lubricant setup value SL for the lubrication actuator 31,...,32' of the rolling stand 10, as well as the coolant setup value SC for the cooling actuator 41,...,42' assigned to the rolling stand 10. Furthermore, the setup model 200 specifies a lower and an upper emulsion limit value E min and E max: these values ​​do not necessarily represent technological limits of the emulsion actuator 21,...,23', but rather the tolerance range within which the output rate of emulsion 20 can be varied without affecting the desired rolling result. Furthermore, the technological limits of the lubricant spray bars 31,...,32' and the coolant spray bars 41,... are also present in the setup model 200.,42' in the form of a minimum and maximum lubricant rate L min , L max for the lubrication actuator or a minimum and maximum coolant rate C min and C max for the cooling actuator.

[0062] Finally, in the first process step S1, a minimum temperature Tmin and a maximum temperature Tmax, as well as a minimum and a maximum coefficient of friction µmin and µmax, are specified for strip 100. These values ​​also represent tolerance ranges within which a desired rolling result is achieved. The specifications can be provided either by the setup model 200 or by another independent entity, such as another processing unit or an operator. The specification or knowledge of all the aforementioned parameters is required in the first step S1. FIG 2 symbolized by corresponding arrows.

[0063] In the second step S2, the rolling pass i is executed in the rolling stand 10: the emulsion actuator (corresponding to the emulsion spray bars 21,...,23' constituting the emulsion actuator) is set to the predefined emulsion setup value SE, the lubrication actuator (or the corresponding lubricant spray bars 31,...,32') to the lubricant setup value SL, and the cooling actuator (or the corresponding coolant spray bars 41,...,42') to the coolant setup value Sc. This can be done, for example, by transmitting the respective setup values ​​to the basic automation 60 of the cold rolling mill and is described in FIG 2 represented by arrows extending to the right into the rectangle symbol of basic automation 60.

[0064] Furthermore, during the rolling process i, the actual strip temperature T' of the strip 100 is determined by means of one or more temperature sensing devices 51, 52. The temperature sensing devices 51, 52 are arranged on the entry and / or exit side of the rolling stand 10 (or on both sides of the rolling stand 10 if it is operated as a reversing rolling stand). In particular, if the temperature sensing devices 51, 52 are designed as pyrometers, the arrangement is such that the strip surface being measured is largely free of residues of emulsion 20 or coolant 40 applied to the strip 10.

[0065] Furthermore, one or more actual values ​​M' of the control variables of the rolling stand 10 are recorded by reading them from the basic automation 60 of the cold rolling mill, and an actual friction coefficient µ' is determined from this. FIG 2 It is indicated that the recorded actual values ​​of the control variables M' include at least an actual rolling force F'; in addition, during the rolling pass i, an actual lead δ' of the strip in the rolling stand 10 as well as an actual drive torque Γ' and / or other operating parameters of the rolling stand 10 can also be recorded.

[0066] The aforementioned recording of the actual strip temperature T' and the actual coefficient of friction µ' can be carried out cyclically during the rolling process i in short time intervals with a respective duration of, for example, 10 to 1000 ms; the determination of the actual temperature T' or the actual coefficient of friction µ' is preferably carried out using a statistical method (e.g. median calculation over all recorded values) in order to minimize the influence of incorrect individual values ​​('outliers').

[0067] In the third step S3 of the inventive method, which is carried out during or after the rolling pass i, it is checked whether the actual temperature T' and the actual coefficient of friction µ' are each within the specified limits, whereby three cases are distinguished: The so-called scenario A is characterized in that either the actual strip temperature T' is greater than the maximum temperature T max and at the same time the actual coefficient of friction µ' is less than the minimum coefficient of friction µ min, or that the actual strip temperature T' is less than the minimum temperature T min and at the same time the actual coefficient of friction µ' is greater than the maximum coefficient of friction µ max.

[0068] Scenario A, as explained above, describes a contrary constellation with regard to a change in the emulsion 20 discharged in the respective rolling pass i. Therefore, if scenario A applies (which is the case in FIG 2 (symbolized by '1' at the first branch), the setup values ​​SE specified by setup model 200 for the respective emulsion actuators 21,...,23' are not changed; instead, only the actual strip temperature T' within the control range of the cooling actuator(s) 41,...,42' and the actual coefficient of friction µ' within the control range of the lubrication actuator(s) 31,...,32' are influenced by determining an improved coolant setup value Sc' and an improved lubricant setup value SL'. This determination can be made using corresponding sensitivities (in the node marked 'A' in FIG 2 ) take place, as within the framework of FIG 3 will be explained in more detail.

[0069] The improved coolant setup value Sc' and the improved lubricant setup value SL' are subsequently adopted by setup model 200 for parameter set Λ i (while the emulsion setup value SE remains unchanged for the same parameter set Λ i), which in FIG 2 This is indicated by corresponding arrows leading back to setup model 200. Subsequently, in a later rolling pass characterized by the same parameter set Λ i, setup model 200 specifies the modified, improved setup values ​​SC ' and SL ', while the emulsion setup value SE is retained.

[0070] If scenario A does not apply (in FIG 2 (symbolized by '0' at the first branch), it is checked whether scenario B applies, which is characterized by the fact that either the actual strip temperature T' is greater than the maximum temperature T max and / or the actual coefficient of friction µ' is greater than the maximum coefficient of friction µ max, or that the actual strip temperature T' is less than the minimum temperature T min and / or the actual coefficient of friction µ' is less than the minimum coefficient of friction µ min.

[0071] Scenario B, as explained above, describes a similar situation with regard to a change in the emulsion 20 released in the respective rolling pass i. Therefore, in this case, the setup values ​​SE for the emulsion actuator 21,...,23' may also be changed if the actual strip temperature T' cannot be sufficiently influenced within the control range of the cooling actuator 41,...,42' and / or the actual coefficient of friction µ' cannot be sufficiently influenced within the control range of the lubrication actuator 31,...,32' (namely, when the cooling and / or lubrication actuator 41,...,42' or 31,...,32' reaches its respective control limits).

[0072] In contrast to scenario A, in scenario B the specified minimum and maximum values ​​for the actual strip temperature T' and the actual coefficient of friction µ' (in addition to being simultaneously exceeded or fallen below) can also be exceeded or fallen below individually: in this case, only an improved setup value SC' or SL' and, if necessary, an improved emulsion setrup value SE' are determined. This determination can in turn be based on corresponding sensitivities (in FIG 2 in the node marked 'B') as also within the framework of FIG 3 will be explained in more detail.

[0073] In summary, for scenario B, an improved coolant setup value SC' and / or an improved lubricant setup value SL', as well as, if applicable, an improved emulsion setup value SE', are determined. The improved emulsion setup value SE' is determined such that it falls within the limits specified by setup model 200 and is therefore greater than or equal to the lower emulsion limit E min and less than or equal to the upper emulsion limit E max. Subsequently, the improved setup values ​​SC', SL', and SE'—provided they have been determined for the considered rolling pass i—are again adopted by setup model 200 for the parameter set Λ i.

[0074] If scenario B also does not apply in addition to scenario A (in FIG 2 (symbolized by '0' at the second branch), this is the trivial case in which both the actual strip temperature T' and the actual coefficient of friction µ' are within the specified limits and consequently no improved setup values ​​are determined and adopted by setup model 200 (in FIG 2 (symbolized by the lowest, empty node). A subsequent rolling pass, characterized by the same parameter Λ i as the rolling pass i under consideration, is therefore also executed with the same, unchanged setup values ​​SC , SL , SE.

[0075] According to the in FIG 3A und FIG 3B illustrated examples for scenario A (in FIG 3A und 3B (Each marked with 'A') an improved coolant setup value SC' is determined based on a first sensitivity σ1, and an improved lubricant setup value SL' is determined based on a second sensitivity σ2. The first sensitivity σ1 represents the functional relationship between the actual strip temperature T' of the strip 100 rolled in rolling pass i, the coolant flow rate ΦC set at the cooling actuator 41,...,42', and the strip thickness d of the strip 100. Based on this relationship, by changing the flow rate ΦC in the form of the improved coolant setup value SC', a strip temperature T' within the temperature range between the minimum and maximum temperatures Tmin and Tmax can be expected for a subsequent rolling pass with the same parameters Λi as in the considered rolling pass i.

[0076] Similarly, the second sensitivity σ2 describes the functional relationship between the actual coefficient of friction µ' and the set flow rate of lubricant Φ L through the lubrication actuator, from which, in turn, by changing the flow rate Φ L in the form of the improved lubricant setup value SL ' for a subsequent, similar rolling operation, an actual coefficient of friction µ' can be expected that lies between the minimum and the maximum coefficient of friction µ min and µ max.

[0077] The improved setup values ​​are determined using the first and second sensitivities σ1 and σ2 such that either the improved coolant setup value SC' lies between the minimum and maximum coolant rates C min and C max, and the improved lubricant setup value SL' lies between the minimum and maximum lubricant rates L min and L max, or, in the case of exceeding or falling below these values ​​(as a result of the determination using the first or second sensitivity σ1 or σ2), are limited to these values ​​in order to reflect the technological limits of the cooling or lubrication actuators accordingly.

[0078] Because – as described above – scenario A represents a contrary constellation with regard to a change in the amount of emulsion dispensed, this is not changed in scenario A according to the invention; instead, only the actual strip temperature T' and the actual coefficient of friction µ' are influenced independently of each other within the control range of the cooling actuator or the lubrication actuator.

[0079] The alternative embodiment of FIG 3B differ from the one in FIG 3A However, if only the improved coolant setup value SC' and the improved lubricant setup value SL' are determined in that order, the same result is achieved.

[0080] FIG 4A , 4B In contrast to scenario A, this represents FIG 4A illustrated example for scenario B (in FIG 4A and 4B (each symbolized by 'B') a constellation in which - as in FIG 2 As indicated, either the actual strip temperature T' exceeds or falls below the specified temperature limits, or the actual coefficient of friction µ' exceeds or falls below the specified limits, or both occur simultaneously: in all three of these sub-scenarios, unlike scenario A, there is a synergistic constellation with regard to the emulsion actuators, so that for a future rolling pass (with the same parameters Λ i ), in addition to a change in the setup values ​​for the cooling actuator or the lubrication actuator, a change in the amount of emulsion delivered by the emulsion actuator also has a beneficial effect on correcting the deviation of the actual strip temperature T' or the actual coefficient of friction µ' currently considered in rolling pass i.

[0081] According to the invention, the three synergistic sub-scenarios described can be combined according to the one described in FIG 4A (or FIG 4B The process is handled as shown in the flowchart: Initially, a first and second correction value, Δ1 and Δ2, are each set to zero as auxiliary variables. Next, the actual strip temperature T' is checked: if it is greater than the maximum temperature Tmax or less than the minimum temperature Tmin, the improved coolant setup value Sc' is determined – analogous to scenario A – using a first sensitivity σ1. Otherwise, the process continues with checking the actual coefficient of friction µ'.

[0082] In the event that the improved coolant setup value SC' is determined, it is then checked whether this is smaller than the minimum or larger than the maximum coolant rate C min or C max: if this is not the case, the check of the actual coefficient of friction µ' is continued.

[0083] Otherwise, the determined, improved coolant setup value Sc' is subsequently limited – analogous to scenario A – by the minimum and maximum coolant flow rates C min and C max, respectively. Additionally, in this case, the first correction value Δ 1 is recalculated using a third sensitivity σ3, where the third sensitivity σ3 describes the functional relationship between the actual strip temperature T' and a change ΔΦ E in the flow rate of emulsion through the emulsion actuator in the vicinity of the already set emulsion setup value SE.

[0084] The first correction value Δ1 thus represents (with simultaneous minimum or maximum control of the cooling actuator corresponding to C min or C max) a necessary change in the emulsion rate (delivered by the emulsion actuator onto strip 100) in order to bring the excessively low or high actual strip temperature into the range between the minimum and maximum temperatures T min and T max in a subsequent, identical rolling pass. Following the determination of the first correction value Δ1, the actual coefficient of friction µ' is checked.

[0085] If, during the verification of the actual coefficient of friction µ', it is found that it is greater than the maximum coefficient of friction µ max or less than the minimum coefficient of friction µ min, the improved lubricant setup value SL ' is determined using a second sensitivity σ2 – analogous to scenario A. Otherwise, the determination of the improved emulsion setup value SE ' continues.

[0086] In the event that the improved lubricant setup value SL' is determined, it is then checked whether this is smaller than the minimum or larger than the maximum lubricant rate L min or L max: if this is not the case, the determination of the improved emulsion setup value SE' is continued.

[0087] Otherwise, the determined, improved lubricant setup value SL' is subsequently limited – analogously to scenario A – by the minimum and maximum lubricant flow rates Lmin and Lmax, respectively. Additionally, in this case, the second correction value Δ2 is recalculated using a fourth sensitivity σ4, where the fourth sensitivity σ4 describes the functional relationship between the actual coefficient of friction µ' and a change ΔΦE in the flow rate of emulsion through the emulsion actuator in the vicinity of the already set emulsion setup value SE.

[0088] The second correction value Δ2 thus represents (given a simultaneous minimum or maximum dispersion of the lubrication actuator(s) corresponding to Lmin or Lmax) a necessary change ΔΦE of the emulsion rate (delivered by the emulsion actuator to the strip) in order to bring the excessively low or high actual coefficient of friction µ' into the range between the minimum and maximum coefficients of friction µmin and µmax in a subsequent, identical rolling pass. Following the determination of the second correction value Δ2, the improved emulsion setup value SE' is then determined.

[0089] When determining the improved emulsion setup value SE ', it is first checked whether the first and second correction values ​​Δ 1 and Δ 2 are each zero: If this is the case, it means that the cooling and lubrication actuators do not need to be adjusted (in the above sense), and therefore no improved setup value SE ' is determined: this is symbolized by the empty circle in FIB 4A.

[0090] Otherwise (i.e., if the first and / or second correction values ​​Δ1 and Δ2, respectively, are not equal to zero), the sum Σ = SE + Δ1 + Δ2 is calculated from the (already set) emulsion setup value SE with the first and second correction values ​​Δ1 and Δ2. Again, depending on the technological limits of the emulsion actuator, the improved emulsion setup value SE' is equated either to the lower emulsion limit E min (if the sum Σ is less than the lower emulsion limit E min) or to the upper emulsion limit E max (if the sum Σ is greater than the upper emulsion limit E max). Otherwise - i.e., if the sum Σ lies between the lower and upper emulsion limits E min and E max - the sum Σ is adopted as the improved emulsion setup value SE '.

[0091] The in FIG 4B The alternative embodiment shown for determining improved setup values ​​according to scenario B differs from the one in FIG 4A The only difference is in the order in which the actual temperature T' and the actual coefficient of friction µ' are checked, but otherwise the results for the improved setup values ​​SL ', SC ', SE ' are identical.

[0092] In summary, Scenario B covers several cases in which the actual strip temperature T' and / or the actual coefficient of friction µ' can be corrected: accordingly, at least one improved coolant setup value SC' and / or one improved lubricant setup value SL' and / or one improved emulsion setup value SE' is determined, which are then adopted by setup model 200 for the parameter set Λ i, so that a future rolling pass carried out with the same parameters Λ i as the currently considered rolling pass i will be performed with the corresponding improved setup values. How many or which of these improved setup values ​​are specifically determined in Scenario B depends on the individual case, which is explained in FIG 4Aand 4B improved setup values ​​Sc', SL' and SE' are symbolized by the arrow from node 'B', enclosed in curly brackets. Reference symbol list

[0093] 10 Rolling stand 11, 11'Work roll 12 Roll gap 13, 13'Support, intermediate roll 14 Strip direction 20 Emulsion 21,...,23'Emulsion actuator, emulsion spray bar 30 Lubricant 31,...,32'Lubricating actuator, lubricant spray bar 40 Coolant 41,...,42'Cooling actuator, coolant spray bar 51, 52Temperature sensing device 60Basic automation 70Computer unit 100Strip 200Setup model A, BScev. C min , C max minimum, maximum coolant rate dBand thickness d 1 , d 2 , d 3 application distance D i thickness range E min , E max lower, upper emulsion limit F'actual rolling force irolling stroke L min , L max minimum, maximum lubricant rate M'actual control variable values ​​Q i material quality range R i stroke removal range S1, S2, S3 process step SC coolant setup value SC 'improved coolant setup value SE emulsion setup value SE 'improved emulsion setup value SL lubricant setup value SL 'improved lubricant setup value T'actual strip temperature T min , T max minimum, maximum temperature V i strip speed range δ'Actual lead Δ1, Δ2 Correction value ΦC Coolant flow rate ΔΦE Change in emulsion flow rate ΦL Lubricant flow rate Γ'Actual drive torque Λi Parameter set u'Actual coefficient of friction µmin, µmax Minimum, maximum coefficient of friction σ1,...,σ4 Sensitivity ΣSum

Claims

1. Method for determining improved setup values ​​for cold rolling a strip (100) in one or more passes (i) in a rolling stand (10), wherein the rolling stand (10) comprises two work rolls (11, 11') for forming a roll gap (12), an emulsion actuator (21,...,23') for supplying emulsion (20) to the work rolls (11, 11') and / or into the roll gap (12), and a lubrication actuator (31,...,32') configured to supply lubricant (30) in a range between a minimum and a maximum lubricant rate (L min , L max ) to discharge onto the strip (100) and / or the work rolls (11, 11'), - a cooling actuator (41,...,42') is assigned to the rolling stand (10), which is configured to discharge coolant (40) in a range between a minimum and a maximum coolant rate (C) min , C max ) to output onto the tape (100), - and wherein each roller stitch (i) is defined by a parameter set (Λ i) is characterized, - wherein in a first step (S1) before each rolling pass (i) -- a minimum and a maximum temperature (T) for the strip (100) min , T max ) and a minimum and a maximum coefficient of friction (µ) min , µ max ) are specified, and -- from a setup model (200) for the emulsion actuator (21,...,23') an emulsion setup value (S E ) as well as a lower and an upper emulsion limit (E min , E max ), for the lubrication actuator (31,...,32') a lubricant setup value (S L ) and for the cooling actuator (41,...,42') a coolant setup value (S C ) are specified, - wherein in a second step (S2) during each rolling pass (i), in which the strip (100) is guided through the rolling gap (12), -- the emulsion actuator (21,...,23') is set to the emulsion setup value (S E ), the lubrication actuator (31,...,32') to the lubricant setup value (S L) and the cooling actuator (41,...,42') to the coolant setup value (S C ) are set, -- with the aid of a temperature sensing device (51, 52) an actual strip temperature (T') of the strip (100) is determined, -- and one or more actual control variable values ​​(M') of the rolling stand (10) are recorded and an actual friction coefficient (u') is determined from this, - wherein in a third step (S3) -- in a scenario (A) in which --- either the actual strip temperature (T') is greater than the maximum temperature (T max ) and the actual coefficient of friction (u') is smaller than the minimum coefficient of friction (µ) min ) is, --- or in which the actual band temperature (T') is less than the minimum temperature (T) min ) and the actual coefficient of friction (u') is greater than the maximum coefficient of friction (µ) max ) is an improved coolant setup value (S C ') and an improved lubricant setup value (S L ') determined and by the setup model (200) for the parameter set (Λ i) are adopted, -- or in a scenario (B) in which --- either the actual band temperature (T') is greater than the maximum temperature (T max ) and / or the actual coefficient of friction (µ') is greater than the maximum coefficient of friction (µ max ) is, --- or in which the actual band temperature (T') is less than the minimum temperature (T) min ) and / or the actual coefficient of friction (u') is less than the minimum coefficient of friction (µ) min ) is the improved coolant setup value (S C ') and / or the improved lubricant setup value (S L ') and / or an improved emulsion setup value (S E '), which is greater than or equal to the lower emulsion limit (E min ) and less than or equal to the upper emulsion limit (E max ) is determined and by the setup model (200) for the parameter set (Λ i ) will be taken over.

2. The method of claim 1, wherein in scenario (A) - the improved coolant setup value (Sc') is determined based on a first sensitivity (σ1) as a value between the minimum and the maximum coolant rate (C). min , C max ), - and the improved lubricant setup value (S L ') based on a second sensitivity (σ2) as a value between the minimum and the maximum lubricant rate (L min , L max ) is determined.

3. Method according to claim 1 or 2, wherein in scenario (B) - first a first and a second correction value (Δ1, Δ2) are set to zero, - in the case where the actual strip temperature (T') is greater than the maximum temperature (T max ) or smaller than the minimum temperature (T min ) is the improved coolant setup value (S C ') is determined based on an initial sensitivity (σ1) and additionally, if the determined improved coolant setup value (S C') less than the minimum or greater than the maximum coolant rate (C min , C max ) is the minimum or maximum coolant rate (C min , C max ) is equated and the first correction value (Δ1) is recalculated using a third sensitivity (σ3), and - in the case where the actual coefficient of friction (u') is greater than the maximum coefficient of friction (µ) max ) or smaller than the minimum coefficient of friction (µ) min ) is the improved lubricant setup value (S L ') is determined using a second sensitivity (σ2) and additionally, if the determined improved lubricant setup value (S L ') smaller than the minimum or larger than the maximum lubricant rate (L min , L max ) is the minimum or maximum lubricant rate (L min , L max) is set equal to and the second correction value (Δ2) is recalculated using a fourth sensitivity (σ4), and - in the case that the first and / or second correction value (Δ1, Δ2) are not equal to zero, a sum (Σ) of emulsion setup value (S E ), first and second correction values ​​(Δ1, Δ2) are formed, where the improved emulsion setup value (S) E ') -- the lower emulsion limit (E min ) is equated if the sum (Σ) is smaller than the lower emulsion limit (E) min ) is, or -- the upper emulsion limit (E max ) is equated if the sum (Σ) is greater than the upper emulsion limit (E) max ) is, and -- otherwise is equated to the sum (Σ).

4. Method according to one of the preceding claims, wherein the lubricant (30) is applied to the strip (100) at a certain first application distance (d1) in front of the roll gap (12) or directly to the work rolls (11, 11') at the entry side.

5. Method according to one of the preceding claims, wherein the coolant (40) is applied directly to the strip (100) at a second application distance (d2) in front of the roll gap (12) or at a third application distance (d3) behind the roll gap (12).

6. Method according to one of the preceding claims, wherein the actual values ​​of the control variables (M') include at least one actual rolling force (F').

7. Method according to one of the preceding claims, wherein the actual values ​​of the control variables (M') further comprise an actual lead (δ') and / or an actual drive torque (Γ') of the work rolls (11, 11').

8. Method according to any of the preceding claims, wherein the parameter set (Λ i) for the rolling cut (i) a thickness range (D i ), a sampling area (R i ), a belt speed range (V i ) and at least one material quality range (Q i ) includes.

9. Method according to one of the preceding claims, wherein the temperature detection device (51, 52) is designed in the form of a pyrometer arranged on the inlet or outlet side of the rolling stand (10).

10. Method according to any of the preceding claims, wherein the lubricant (30) comprises at least 80% pure oil.

11. Method according to any of the preceding claims, wherein the minimum temperature (T min ) in a range of 50°C - 70°C and the maximum temperature (T max ) in a range of 120°C to 160°C.

12. Method according to any of the preceding claims, wherein the coolant (40) comprises at least 80% water.

13. Method according to claim 12, wherein the emulsion (20) is used as the coolant (40).

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