METHOD FOR OPERATING A WARM RIBBON PRODUCTION PLANT COMPUTER PROGRAM PRODUCT AND WARM RIBBON PRODUCTION PLANT FOR MANUFACTURING A WARM RIBBON

Description

[0001] The present invention relates to a method for operating a hot strip production plant for manufacturing hot strip. Furthermore, the present invention relates to a hot strip production plant for manufacturing hot strip.

[0002] Known in the art, hot strip production plants heat a hot-rolled metallic material, in particular a slab, using a gas-fired furnace, especially a walking beam furnace. After hot rolling into a hot strip, the hot strip is cooled with a cooling device, in particular a laminar cooling device, and wound into a coil.

[0003] The objective of known hot strip production plants is to produce a hot strip which, before being wound into a coil, has a temperature that is as constant as possible in the longitudinal direction, in the width direction and in the thickness direction.

[0004] However, this objective can only be achieved to a limited extent, as, among other things, local temperature inhomogeneities can occur during the heating of the hot-rolled metallic material in the furnace due to the contact surfaces of the slabs within the furnace.

[0005] The reason for the aforementioned objective of maintaining a constant temperature of the hot strip before winding is to achieve the most homogeneous material properties of the hot strip before winding.

[0006] It is also known that hot-rolled strip is further processed into cold-rolled strip and / or coated strip in a downstream strip treatment plant, whereby the strip undergoes heat treatment, particularly depending on the respective metal composition. In particular, a treatment plant can be a continuous galvanizing line (also: continuous galvanizing line (CGL)).

[0007] DE 10 2021 212 902 A1 describes a process for producing a fine-grained steel material in which a pre-product is heated and hot-rolled into a hot strip and then wound up after cooling in a rapid cooling process.

[0008] The invention is based on the objective of providing an improvement or an alternative to the prior art.

[0009] According to a first aspect of the invention, the problem is solved by a method for operating a hot strip production plant for the production of a hot strip, wherein the hot strip production plant a hot rolling mill for hot rolling the hot strip from the hot-rolled metallic stock; a reel for winding the hot strip onto a coil; and comprising at least one dynamic temperature control element; wherein the method comprises the following process steps: hot rolling the hot strip from the hot-rolled metallic stock using the hot rolling mill; tempering the hot-rolled metallic stock and / or the hot strip using the dynamic temperature control element; and winding the hot strip onto the coil; wherein the tempering of the metallic hot-rolled material and / or the hot strip is controlled or regulated by means of the dynamic temperature control element such that the hot strip has a varying temperature profile in a longitudinal direction before the hot strip is wound up, wherein the varying temperature profile has a minimum temperature and a maximum temperature.

[0010] It is understood that the sequence of the above-described process steps can also occur in a different order without abandoning the aspect of the invention described here.

[0011] Preferably, the hot strip production plant may include a heating device for heating and / or homogenizing the metallic hot-rolled material, wherein the process may include the preferred process step: Heating and / or homogenizing the hot-rolled metallic material with the heating device.

[0012] The material properties of a metallic product, in particular a hot-rolled strip and / or a cold-rolled strip, depend not only on the material composition but also on the microstructure of the metal, especially if the metal contains iron and carbon and can therefore also be called steel.

[0013] The phase transformation process of steel influences its microstructure, particularly the ferrite, pearlite, bainite, martensite, and austenite content. This microstructure, in turn, affects its properties. Generally, locally varying cooling curves in steel result in correspondingly different material properties.

[0014] A low pearlite content can be achieved through rapid cooling, resulting in lower hardness and / or improved formability. Alternatively, slower cooling can lead to greater hardness.

[0015] In other words, there is a relationship between the properties of a metallic strip and the temperature control during its production.

[0016] Hot-rolled strip is typically wound at a temperature at which the microstructural transformation of the metal is not yet complete. The winding temperature is typically between 300 °C and 750 °C. This temperature range is merely an example to illustrate the typical range. The exact winding temperature depends on the alloy and / or the quality of the strip.

[0017] It has been shown that the production of hot-rolled strip using state-of-the-art hot-rolled strip production equipment leads to inhomogeneity in the material properties. For example, the cooling of the hot-rolled strip within the coil results in a change in its material properties, particularly in the longitudinal direction, since the outer and inner coils cool down faster than the central coils. This inhomogeneity in material properties occurs even when the temperature of the hot-rolled strip is kept as constant as technically possible before winding.

[0018] Even subsequent processing of the initially wound hot-rolled strip in a strip processing plant, particularly with a continuous galvanizing line, leads to a further processed strip with different material properties, even if the strip is annealed in the strip processing plant. These differences – as has now been recognized – can be attributed, among other things, to the inhomogeneous cooling behavior of the hot-rolled strip in the coil and thus to the precipitation behavior and / or grain growth and / or phase fractions that influence the microstructure.

[0019] In contrast to the previously known objective of winding the manufactured hot-rolled strip at a temperature that is as constant as possible, it is now specifically proposed here to temper the hot-rolled strip during its production before winding it into a coil in such a way that the hot-rolled strip has a varying temperature profile before winding.

[0020] "Temperature control" refers to the adjustment of the temperature of the hot-rolled metal stock and / or hot-rolled strip by means of at least one dynamic temperature control element, in particular the adjustment of the temperature of the hot-rolled metal stock and / or hot-rolled strip in the longitudinal direction of the metal stock and / or hot-rolled strip, and especially the adjustment of the temperature of the hot-rolled metal stock and / or hot-rolled strip as a function of a coordinate in the longitudinal direction of the metal stock and / or hot-rolled strip. In other words, the hot-rolled metal stock and / or hot-rolled strip can be tempered in such a way that a temperature varying in the longitudinal direction of the metal stock and / or hot-rolled strip is set within the metal stock and / or hot-rolled strip. Thus, a variable temperature can be set along the length of the metal stock and / or hot-rolled strip.

[0021] A "dynamic temperature control element" is understood to be a device configured to generate a varying temperature profile that corresponds to a varying temperature profile of the hot strip upstream of the coiler, with a value greater than or equal to 0.1 K / (m * mm) (Kelvin per 1 m length of the hot strip and per 1 mm thickness of the hot strip), preferably greater than or equal to 0.2 K / (m * mm) or greater than or equal to 0.4 K / (m * mm), and particularly preferably greater than or equal to 0.8 K / (m * mm). In particular, the dynamic temperature control element can achieve the aforementioned values ​​for the varying temperature profile by heating and / or cooling.

[0022] Tempering makes it possible to set different and / or variable temperatures along the length of the hot-rolled metal and / or the hot strip.

[0023] To achieve a variable temperature distribution in a hot-rolled strip, tempering can take place before hot rolling, i.e., in conjunction with a metallic hot-rolled material, and / or between two rolling stands and / or after hot rolling, i.e., in conjunction with a hot-rolled strip. Since the result of tempering persists in the hot-rolled strip in any case, for the purposes of this application, tempering of a hot-rolled strip can be understood as tempering before, during, and / or after hot rolling.

[0024] Tempering can be understood as partial or complete cooling of the metallic hot-rolled material and / or the hot strip and / or partial maintenance of the temperature of the metallic hot-rolled material and / or the hot strip and / or partial or complete heating of the metallic hot-rolled material and / or the hot strip.

[0025] This ensures that the microstructure of the hot-rolled strip, and therefore its material properties, are as homogeneous as possible after the coil has cooled. As a result, the quality of the hot-rolled strip, and also of the further processed strip, especially the cold-rolled strip, can be improved.

[0026] In this context, a "varying temperature profile" is understood to mean a temperature profile that cannot be achieved by aiming for the most homogeneous temperature profile possible, as this would lead to inhomogeneity in the material properties. In other words, a planned varying temperature profile exhibits a continuous connection between at least one maximum and one minimum value for a designated temperature and / or a high point and one low point for a designated temperature of the hot-rolled strip before winding.

[0027] It has been shown that by varying the temperature profile before winding the hot strip, the precipitation behavior and / or grain growth and / or different phase fractions of the hot strip can be locally altered in such a way that this targeted change, together with another unavoidable or deliberately induced local change in the precipitation behavior and / or grain growth and / or phase fractions due to inhomogeneous temperature control, can lead to overall homogeneous material properties up to the cooled hot strip or up to the cooled further processed strip, in particular cold strip, or up to the finished product.

[0028] The term "material properties" may refer to one, two, three, four or more than four of the following parameters: yield strength, tensile strength, elongation at break, r value, n value, brittle fracture, transition temperature, phase fractions (austenite, ferrite, pearlite, bainite, martensite), electrical properties and / or hysteresis losses or the like.

[0029] Optionally, it is suggested here to also set a varying temperature profile in the width direction of the hot strip, since the end faces of the strip also cool down faster than the center of the strip.

[0030] A "heating device" is understood to be a device designed for heating, homogenizing, annealing, and / or maintaining the temperature of a hot-rolled metal stock. In other words, a heating device can be configured to condition and / or prepare a hot-rolled metal stock for processing by a hot rolling mill. In this way, the temperature of a hot-rolled metal stock can be set for hot rolling by a heating device. A heating device can thus be understood as a link between an upstream process step and a hot rolling mill.

[0031] A heating device can be designed as an inductor. Furthermore, a heating device can also be gas-fired, in particular using hydrogen and / or a fossil fuel.

[0032] According to one variant, a metallic hot-rolled product can be heated by a heating device starting at a low temperature or room temperature to a hot-rolling temperature.

[0033] According to a second variant, a metallic hot-rolled product can be transferred directly with initial heat from a casting device for metallic hot-rolled products into a heating device and heated there to a hot-rolling temperature.

[0034] According to a third variant, a hot-rolled metallic product can be annealed by a heating device at a constant temperature.

[0035] According to a fourth variant, a temperature distribution in a rolled metallic product can be homogenized using a heating device. In other words, a uniform temperature distribution in a hot-rolled metallic product can be achieved within a heating device.

[0036] It should be expressly mentioned that the above variants do not necessarily have to be mutually exclusive, so that any or at least a subset of the above functions can be performed by a single heating device.

[0037] It is understood that a plurality of heating devices can also be used to heat the hot-rolled metallic material without departing from the present aspect of the invention.

[0038] It is also preferable that the process proposed here can be carried out on a Steckel mill. Therefore, a Steckel mill can also be understood as a "hot strip production plant" in this context.

[0039] In other words, a varying temperature profile is preferably provided here, the maximum temperature of which, in the longitudinal direction of the hot strip, is at least 1% higher than the minimum temperature in the longitudinal direction of the hot strip. Furthermore, the maximum temperature is preferably greater than or equal to 2% higher than the minimum temperature, more preferably greater than or equal to 3%, and particularly preferably greater than or equal to 5%. Preferably, the maximum temperature is greater than or equal to 4% higher than the minimum temperature, more preferably greater than or equal to 6%, and particularly preferably greater than or equal to 7%.

[0040] Optionally, the maximum temperature may be less than or equal to 11% higher than the minimum temperature, preferably less than or equal to 9%, and particularly preferably less than or equal to 7%.

[0041] Expressed in absolute values, a temperature profile can be provided whose maximum temperature is greater than or equal to 5 °C higher than the minimum temperature, preferably greater than or equal to 10 °C and particularly preferably greater than or equal to 25 °C. Preferably, the maximum temperature is greater than or equal to 15 °C higher than the minimum temperature, more preferably greater than or equal to 20 °C and particularly preferably greater than or equal to 30 °C.

[0042] Optionally, the maximum temperature is less than or equal to 45 °C higher than the minimum temperature, preferably less than or equal to 40 °C and particularly preferably less than or equal to 35 °C.

[0043] It has been shown that achieving the proposed varying temperature profile of the hot-rolled strip in the longitudinal direction requires a dynamic temperature control element. A higher degree of temperature dynamics can be achieved with the dynamic temperature control element than with a heating device in the hot-rolled strip production plant, particularly with a gas-fired heating device. It is understood that multiple dynamic temperature control elements can also be used to solve the problem, in particular a cooling device and an inductive heating device.

[0044] The temperature control of the hot strip before winding is carried out using a control system or regulation system that is data-coupled with the dynamic temperature actuator.

[0045] A control system can have a continuous linear controller, in particular a PD controller or a PID controller.

[0046] A dynamic temperature control element can include a cooling device, in particular a laminar cooling device and / or a transfer bar cooling device (also TBC for transfer bar cooling) and / or a compact cooling device with coolant nozzles for dispensing a coolant and / or an intermediate stand cooling device. A cooling device can be arranged between the hot rolling mill and the coiler. It is known that cooling devices can have a cooling rate of 50 K / s, so that the hot strip can be cooled from a thickness-averaged temperature of 1,150 K to a thickness-averaged temperature of 650 K in a cooling time of 10 s using such a cooling device.

[0047] This cooling rate, or in other words, the rate at which the temperature profile in the hot strip can be changed, is particularly fast compared to a gas-fired heating device and can—as has been shown—sufficiently influence the precipitation behavior and / or grain growth and / or different phase fractions in accordance with the overall objective. Therefore, a control system can be coupled with a cooling device and the cooling device can be adjusted accordingly to achieve the varying temperature profile proposed here.

[0048] Optionally, a dynamic temperature controller can include a heating device, in particular an inductive heating device. An inductive heating device can preferably be arranged upstream of the reel.

[0049] Such a heating device can have a nominal power density in conjunction with the hot strip of greater than or equal to 2 × 10⁵ W / m², preferably greater than or equal to 5 × 10⁵ W / m², and particularly greater than or equal to 1 × 10⁶ W / m². It has been shown that the precipitation behavior and / or grain growth and / or different phase fractions can be sufficiently influenced, corresponding to the overall objective, with the nominal power densities proposed above for a heating device.

[0050] A heating device can function as part of a dynamic temperature control element and be arranged between the hot rolling device and the coiler, in particular in front of or behind a cooling device.

[0051] Furthermore, a heating device can preferably be arranged as part of a dynamic temperature control element between the heating device and an outlet of the hot rolling device, in particular in front of one of the rolling stands of the hot rolling device.

[0052] A heating device can also preferably be arranged as part of a dynamic temperature control element between two rolling stands of the hot rolling mill.

[0053] It is understood that a dynamic temperature control element cannot be understood to be a reel heating device which is set up for temperature control of a bundle, such as a reel heating device known from a Steckel Mill.

[0054] The term "outlet" refers to the side of a hot rolling mill where the hot-rolled strip is designed to exit the mill. In other words, it refers to the end of the hot rolling mill that, with regard to the intended material flow of the hot-rolled strip, is located on the reel side.

[0055] Optionally, the tempering of the metallic hot-rolled material and / or the hot strip is carried out over a length of greater than or equal to 95% of the metallic hot-rolled material and / or the hot strip, preferably over a length of greater than or equal to 97.5% or over a length of greater than or equal to 99% and particularly preferably over the entire length.

[0056] This proposal also addresses the tempering of significant areas of the head and / or end of a hot-rolled strip, particularly by means of a continuous temperature variation within the strip. This advantageously allows the head and / or end to be included in the present approach, thus extending the benefits described here to the head and / or end of the strip.

[0057] Particularly homogeneous material properties for the finished product and / or for the cooled further processed strip, especially cold strip, and / or for the cooled hot strip can be achieved if the varying temperature profile has a continuous profile, in particular a continuous profile over a length of greater than or equal to 50% of the metallic hot-rolled material and / or the hot strip, preferably over a length of greater than or equal to 95% or over a length of greater than or equal to 98% and particularly preferably over the entire length of the metallic hot-rolled material and / or the hot strip.

[0058] In this context, "continuous progression" refers to a continuous progression in the mathematical sense.

[0059] Furthermore, particularly homogeneous material properties in the sense described above can be achieved if the temperature control of the metallic hot-rolled stock and / or the hot strip is carried out by means of the dynamic temperature control element over a length of greater than or equal to 95% of the metallic hot-rolled stock and / or the hot strip, preferably over a length of greater than or equal to 97.5% or over a length of greater than or equal to 99% and particularly preferably over the entire length of the metallic hot-rolled stock and / or the hot strip.

[0060] Particularly preferably, the varying temperature profile exhibits, at least in certain areas, a temperature difference of greater than or equal to 0.1 K / (m * mm) (Kelvin per 1 m length and per 1 mm thickness of the hot-rolled strip) per 1 m of length and per 1 mm thickness of the hot-rolled strip, preferably greater than or equal to 0.2 K / (m * mm) or greater than or equal to 0.4 K / (m * mm), and particularly preferably greater than or equal to 0.8 K / (m * mm). In particular, the aforementioned values ​​correspond to a varying temperature profile of the hot-rolled strip upstream of the coiler, regardless of the arrangement of the dynamic temperature control element within the hot-rolled strip production plant.

[0061] The above values ​​for varying the temperature profile using the dynamic temperature control element allow for particularly advantageous temperature gradients to be achieved in the above sense, which, in combination with the cooling behavior of the hot-rolled strip and / or compensating for temperature differences through storage of the hot-rolled metallic material in a heating device and / or the subsequent processing of the cold-rolled strip, lead to particularly advantageous material properties, especially in the sense described above.

[0062] Optionally, a maximum temperature at one end of the hot strip and a minimum temperature in a middle area of ​​the hot strip can be provided for the varying temperature profile.

[0063] Preferably, for the varying temperature profile at each end of the hot strip, a maximum temperature and a minimum temperature can be provided in a middle area of ​​the hot strip.

[0064] Furthermore, preferably, a minimum temperature and a maximum temperature can be provided in a middle area of ​​the hot strip to accommodate the varying temperature profile at each end.

[0065] The varying continuous temperature profile can have a bathtub function, the profile of which is designed analogously to a wall profile of a bathtub in cross-section, with the maximum temperatures at the respective end of the profile and the minimum temperature in the middle area.

[0066] The middle section is arranged between the ends of the hot strip in the longitudinal direction of the hot strip.

[0067] It has been shown that a wound hot strip cools down faster, especially at its outer windings, than in a middle area, with the inner windings also cooling down faster than the inner area.

[0068] It was found that the varying temperature profile of the hot strip proposed here before winding leads to precipitation behavior and / or grain growth and / or phase fractions of the hot strip, which can contribute to a largely homogeneous microstructure and thus to largely homogeneous material properties of the hot strip until the hot strip has completely cooled on the coil.

[0069] Optionally, at least two or at least three high points away from the ends of the hot strip, i.e. in the middle area of ​​the hot strip, are also provided for the varying temperature profile.

[0070] When heating hot-rolled metal stock with a heating device, particularly a walking beam heating device, the contact surfaces of the metal stock can lead to locally lower temperatures of the stock and, after hot rolling, also of the hot-rolled strip. This can result in locally inhomogeneous precipitation behavior and / or grain growth and / or phase fractions, a locally differing microstructure, and consequently, varying material properties throughout the entire temperature control process, up to and including winding of the hot-rolled strip or complete cooling of the hot-rolled strip to ambient temperature.

[0071] It is proposed here to heat the metallic hot-rolled material and / or the hot strip more intensely at the points corresponding to the inhomogeneous temperature caused by the heating device, so that the varying temperature profile has correspondingly arranged high points.

[0072] It has been shown that in this way the precipitation behavior and / or grain growth and / or different phase proportions, the microstructure and thus the material properties of the hot strip can be changed in such a way that more constant material properties can be achieved for the cooled hot strip.

[0073] Some strip processing plants have a continuous operating mode, whereby a plurality of wound hot strips are joined together at the input side and are continuously processed by the strip processing plant.

[0074] Due to production planning, it may be necessary to arrange strips of different material qualities adjacent to each other, join them together and process them immediately one after the other.

[0075] This can lead to a situation where material A, with an annealing temperature of 720 °C, has to be produced directly before material B, with an annealing temperature of 750 °C. Since even the heating element of a strip processing line has inertia, a transition zone can occur that cannot be treated at the ideal annealing temperature.

[0076] Optionally, a varying temperature profile is suggested here, which provides a maximum temperature and a minimum temperature at opposite ends of the hot strip.

[0077] As has been shown, this allows the precipitation in the hot strip and / or the grain growth and / or the formation of different phase fractions to be trimmed in such a way that, during further treatment of the hot strip in a strip treatment plant at successive different annealing temperatures of successively treated material grades, a strip with largely homogeneous material properties can be produced overall.

[0078] Particularly good results can be achieved if the procedure includes the following steps: Capturing a mechanical property of the produced hot-rolled strip, in particular with an IMPOC (Impulse Magnetic Process Online Controller); and deriving a necessary control or regulation parameter for the dynamic temperature actuator for a subsequent metallic hot-rolled product and / or for a subsequent hot-rolled strip.

[0079] This allows data, particularly data on at least one material property, from an already produced hot-rolled strip to be used to optimize the control and / or regulation of the dynamic temperature actuator for a hot-rolled strip yet to be produced. In particular, the measurement data obtained can be compared with the desired target data. If differences are detected, a change to a control and / or regulation setting can be derived, especially in such a way that an existing deviation in at least one mechanical property is reduced to a minimum or avoided altogether.

[0080] Preferably, the dynamic temperature actuator is controlled or regulated using a process model, in particular a nonlinear process model. The control of the dynamic temperature actuator can be achieved using a model-based controller, in particular a model-based controller based on a nonlinear process model.

[0081] Precise and reliable control can be advantageous in improving the dynamic behavior of thermal processes. Mechanisms influencing temperature-dependent and material-dependent dynamic precipitation behavior, dynamic grain growth, and / or the dynamic formation of different phase fractions can also be used to develop a process model that can serve as a substitute system within a control or regulation framework.

[0082] Such a process model can contain linear or nonlinear model components and be supported by data, especially measurement data.

[0083] A process model can be modeled continuously over time using differential equations to reproduce the dynamics.

[0084] Regardless of whether the process model is used for control or regulation, it can represent the precipitation process and / or the grain size formation process and / or the formation of different phase fractions with greater accuracy than is possible with linear control or using a continuous linear controller, in particular a proportional (P) controller, a proportional-determining (PD) controller, or a proportional-intensity (PID) controller. In particular, the process model, when directly compared to a continuous linear controller, allows for cross-coupling of various quantities and the explicit adherence to process-related boundary conditions, since continuous linear controllers are determined solely by a conservative choice of setting parameters, which is suitable in the optimal case.

[0085] As a result, the use of a process model allows the control or regulation of the temperature control of the metallic rolled material and / or the hot strip in the direction of an advantageous varying temperature profile.

[0086] The use of a process model within the framework of temperature control for rolled metal products and / or hot-rolled strip allows, in particular, model predictive control, since the process model can also be used as a predictive model. In this way, with suitable modeling of the precipitation behavior and / or grain growth and / or the dynamic formation of different phase fractions, it is possible to control the varying temperature profile in such a way that the cooled hot-rolled strip exhibits homogeneous material properties.

[0087] Particularly preferably, the process model can also include the further processing of the hot strip in a downstream strip processing plant, so that the model predictive control of the varying temperature profile is possible in such a way that the hot strip, which has been further processed into a strip in a strip processing plant, can exhibit the desired, as homogeneous as possible, material properties after its complete cooling to the ambient temperature.

[0088] In this context, the process model can also include logistical relationships between the hot strip and the strip processing plant, as well as the process planning of the strip processing plant.

[0089] Particularly advantageous, homogeneous material properties can also be achieved if the process model includes a physical and / or chemical model, especially a metallurgical model.

[0090] Optionally, data from a database can be used to control or regulate the dynamic temperature actuator, in particular data containing metallurgical information and / or process planning information.

[0091] This allows, among other things, the creation of a comparatively simple and / or adaptable empirical process model.

[0092] Linking to a database can also simplify the control or regulation of the dynamic temperature actuator; for example, behavior dependent on the composition of the metal can be taken into account using data from a database and / or an improvement in the homogeneity of the target material properties can be achieved.

[0093] Furthermore, a semi-empirical process model can be considered, which can use data from a database as well as a model based on physical and / or chemical principles, particularly on a metallurgical basis.

[0094] Data can refer to data from the current process, a previous process and / or a subsequent processing process.

[0095] It is particularly advantageous to use values ​​of at least one measured variable for controlling or regulating the dynamic temperature actuator, in particular a temperature measured variable, a metallurgical measured variable, a microstructure component variable, a material property variable, a metal structure variable, a process variable and / or a geometric variable, in particular a casting thickness.

[0096] A process parameter can include, among other things, the casting speed and / or an operating condition of the hot strip production plant and / or a strip treatment plant.

[0097] The use of a measured variable allows, among other things, the adjustment of the varying temperature profile for the next hot strip to be produced, depending on an actual value of a previously produced hot strip.

[0098] Furthermore, the use of measured variables allows for the consideration of cross-coupling between measured variables within the process model.

[0099] Considering measured variables within a process model can also be used to improve the modeling of the process model, especially when using a self-learning process model, particularly when using a neural network.

[0100] Accordingly, a particularly advantageous empirical or semi-empirical process model can be achieved if the process model is self-learning, especially using machine learning, which allows the mapping quality and model depth of the process model to be continuously improved in a comparatively simple way.

[0101] For some parameters, setpoints can be used in addition to measured values ​​of these parameters to control or regulate the dynamic temperature actuator, in particular for a thickness reduction of the hot strip in a rolling stand, a final rolling temperature, a coiling temperature, a cooling strategy, an intermediate strip thickness, a degree of cold forming, an annealing temperature and / or a cooling stop temperature after annealing.

[0102] When measuring microstructural components on hot-rolled strip, particularly before coiling the strip into a coil, especially using a microstructure sensor, particular attention should be paid to measuring the austenite and / or ferrite content. This can advantageously predict the mechanical properties. This prediction can be used, among other things, for controlling the temperature of the hot-rolled metal and / or the hot-rolled strip.

[0103] The determination of material values ​​in the laboratory can also be considered a measured value of a measurand, provided that this is fed into the database and / or otherwise returned to the process model.

[0104] Preferably, the hot-rolled strip can be divided in the longitudinal direction into at least three segments, preferably at least five segments, and particularly preferably at least seven segments, wherein target values ​​for the material properties can be specified, at least implicitly, for each segment. Each segment can have different target values. A continuous or a continuous and differentiable model for a target value can be implemented between the segments.

[0105] Optionally, a loss of hot-rolled strip in the form of scrap generated at the head end and / or the foot end can be taken into account.

[0106] Traditionally, quality release of hot-rolled strip requires that the material quality along the strip's length does not deviate from a defined tolerance range, with the strip being finally released after examination of a material sample. With the manufacturing process proposed here, this traditional process would lead to an undesirable devaluation of the hot-rolled strip. Therefore, an alternative quality release procedure is proposed here: either using a measurement technique (e.g., Impulse Magnetic Process Online Controller (IMPOC)) that is sensitive to the desired material property, or considering a modeled value for the desired material property along the strip's length, which must fall within the specified tolerance.

[0107] Due to material changes in a hot strip production plant (casting and rolling mill) linked to a casting machine, the chemical analysis within a hot strip can vary along its length. With conventional homogeneous processing, this leads to inhomogeneous material properties. This proposal suggests quantifying the material properties of the hot strip in sectors or continuously along its length. This would allow for more homogeneous material properties to be achieved using the proposed method and by modeling the material properties, particularly within the process model.

[0108] It goes without saying that the aforementioned components of a process model can also be advantageously combined.

[0109] According to a second aspect of the invention, the problem is solved by a hot strip production plant for the manufacture of a hot strip, comprising: a hot rolling device for hot rolling the hot strip from a metallic hot-rolled material; at least one dynamic temperature control element; a reel for winding the hot strip onto a coil; and a control device that is data-coupled with the dynamic temperature control element for transmitting control signals; wherein the control device is configured to carry out a method according to the first aspect of the invention.

[0110] It is understood that the advantages of a method for operating a hot strip production plant for the manufacture of a hot strip according to the first aspect of the invention, as explained above, extend directly to a hot strip production plant for the manufacture of a hot strip comprising a control device suitable for carrying out a method according to the first aspect of the invention.

[0111] Preferably, the hot strip production plant includes a heating device for heating and / or homogenizing the metallic hot-rolled material.

[0112] Optionally, the hot strip production plant includes a measuring device for recording a measured quantity, wherein the measuring device is data-coupled with the control device, in particular an IMPOC (Impulse Magnetic Process Online Controller).

[0113] It has already been explained above that the use of measured variables for controlling or regulating the temperature of hot-rolled metal and / or hot-rolled strip can be advantageous. It is therefore understood that these advantages also extend to a hot-rolled strip production plant which has at least one measuring device for recording this at least one measured variable, wherein the at least one measuring device is data-linked to the control unit for transmitting the measured variable values.

[0114] It should be expressly noted that the subject matter of the second aspect can be advantageously combined with the subject matter of the preceding first aspect and the following third aspect of the invention, either individually or cumulatively in any combination within the scope of protection defined by the claims.

[0115] According to a third aspect of the invention, the problem is solved by a computer program product comprising program code means that cause the hot strip production plant according to the second aspect of the invention to execute the steps of the method according to the first aspect when the computer program product is executed on the control device of the hot strip production plant. It is understood that the advantages of a method for operating a hot strip production plant for manufacturing hot strip according to the first aspect of the invention, as explained above, extend directly to a computer program product comprising program code means suitable for carrying out the steps of a method according to the first aspect of the invention.It should be expressly noted that the subject matter of the third aspect can be advantageously combined with the subject matter of the first aspect of the invention, either individually or cumulatively in any combination within the scope of protection defined by the claims. The following terminology should be explained: First, it should be expressly noted that, within the context of this patent application, indefinite articles and numerical terms such as "one," "two," etc., are generally to be understood as "at least" specifications, i.e., "at least one...", "at least two...", etc., unless it is expressly clear from the respective context, or it is obvious or technically necessary for a person skilled in the art, that only "exactly one...", "exactly two...", etc., can be meant.

[0116] In the context of the present patent application, the term "in particular" should always be understood as introducing an optional, preferred feature. The term should not be interpreted as "namely" or "specifically".

[0117] Further advantages, details, and features of the invention will become apparent from the exemplary embodiments described below. Specifically, the following will be shown: Figure 1: Schematic temperature profiles (a), (c) and a corresponding material property (b), (d) for a hot-rolled strip according to a first embodiment; Figure 2: Schematic temperature profiles (a), (c) and a corresponding material property (b), (d) for a hot-rolled strip according to a second embodiment; and Figure 3: Schematic temperature profiles (a), (c) and a corresponding material property (b), (d) for a hot-rolled strip according to a third embodiment.

[0118] In the following description, identical reference numerals denote identical components or identical features, so that a description of a component in relation to one figure also applies to the other figures, thus avoiding repetitive descriptions. Furthermore, individual features described in connection with one embodiment can also be used separately in other embodiments.

[0119] A hot strip 10 (not explicitly shown) has a longitudinal extent 12, a longitudinal extent direction 14 and two ends 16 each.

[0120] The Figs. 1 to 3 In each schematic representation, two temperature profiles 30, 31, 33 in figure sections (a) and (c) as well as in figure sections (b) and (d) show a material property 50, 55 corresponding to the respective temperature profile 30, 31, 33, in particular a tensile strength of the hot strip 10.

[0121] The corresponding sections of the figure are (a) and (b), i.e., the material property 55 in the figure section (b) corresponds to the temperature profile 30, 31 in the figure section (a), as well as the figure sections (c) and (d), i.e., the material property 50 in the figure section (d) corresponds to the temperature profile 33 in the figure section (c).

[0122] Figure sections (a) and (b) are each known, while figure sections (c) and (d) are according to the invention.

[0123] It should be expressly noted that embodiments one to three are in accordance with the Figs. 1 to 3 They can also be combined cumulatively in any way desired.

[0124] For the first embodiment in Fig. 1 It is known that a hot strip production plant has the objective of maintaining a temperature 30 as constant as possible over the longitudinal extent 12 of the hot strip 10.

[0125] After winding, the hot strip 10 cools down at different rates along its longitudinal length 12. While the outer and inner windings cool down relatively quickly, heat builds up in the interior of the coil, so that cooling in the interior of the coil proceeds more slowly.

[0126] As a result, it was found here that this can lead to different precipitation behavior and / or grain growth and / or the formation of different phase proportions, so that the hot strip 10 exhibits an inhomogeneous course of a material property 55 after cooling.

[0127] It is proposed here to design the tempering of the hot strip 10 before winding such that a varying temperature profile 33 is established in the hot strip 10. The varying temperature profile 33 has a bathtub-like shape, with a minimum temperature 40 in a middle region and a maximum temperature 42 at the ends 16 of the hot strip 10.

[0128] Experiments have shown that such a trimmed varying temperature profile 33 can lead to the hot strip 10, after cooling, or a strip 20 (not shown) after further treatment by means of a strip treatment plant, in particular a strip treatment plant having a process step in which the strip is annealed, exhibiting a homogeneous profile 50 of a material property, wherein the profile 50 of the material property exhibits improved homogeneity in particular compared to the known profile 55 of the material property.

[0129] The second embodiment according to Fig. 2Figure 55 shows an inhomogeneity of a material property 55 resulting from a temperature profile 31 as a hot-rolled metallic strip, subsequently hot-rolled to form a hot strip 10, exits the heating device. Since this temperature distribution 31 only extends lengthwise during hot rolling, the temperature profile 31 has already been transferred to a hot strip 10 in section (a) of the figure.

[0130] The temperature distribution 31 has three low points which correspond to the beams of a walking beam heating device, through which the metallic hot-rolled material has not been heated homogeneously in the heating device.

[0131] It is proposed here to design the temperature control of the hot strip 10 before winding such that a varying temperature profile 33 is established in the hot strip 10. Corresponding to the low points of the temperature profile 31, the varying temperature profile 33 exhibits three high points 44.

[0132] Experiments have shown that such a varying temperature profile 33, trimmed with a dynamic temperature control element, can lead to the hot strip 10 exhibiting a homogeneous profile 50 of a material property after cooling, wherein the profile 50 of the material property exhibits improved homogeneity in particular compared to the known profile 55 of the material property.

[0133] The third embodiment according to Fig. 3This shows an inhomogeneity of a material property 55 after the strip 20 exits a continuous strip processing plant. During the production of the hot strip 10, this was achieved according to the temperature profile 30 in the hot strip production plant before winding.

[0134] However, the temperature control of the heating device of the strip processing plant leads to the material property profile 55 after the strip 20 exits the processing plant, since the heating device of the processing plant was adjusted at one end of the strip to achieve a different temperature required for a quality of an adjacent strip. The dynamics of this temperature change in the continuously operated strip processing plant can be seen in the material property profile 55.

[0135] It is proposed here to design the temperature control of the hot strip 10 before winding such that a varying temperature profile 33 is established in the hot strip 10. The varying temperature profile 33 exhibits a minimum temperature 40 at one end 16 of the hot strip 10 and a maximum temperature 42 at the opposite end 16 of the hot strip 10, the temperature profile in the middle region of the hot strip 10 corresponding to the dynamics of the heating device of the downstream continuous strip processing plant.

[0136] Experiments have shown that such a trimmed varying temperature profile 33 can lead to strip 20 exhibiting a homogeneous profile 50 of a material property after further treatment using the strip processing plant, wherein the profile 50 of the material property exhibits improved homogeneity in particular compared to the known profile 55 of the material property. Reference symbol list

[0137] 10 Hot-rolled strip 12 Longitudinal extent of the hot-rolled strip 14 Longitudinal extent direction of the hot-rolled strip 16 Ends of the hot-rolled strip 20 Strip 30 Constant temperature profile before the coiler 31 Temperature profile when exiting the heating device 33 Varying temperature profile 40 Minimum temperature 42 Maximum temperature 44 Peak 50 Mechanical property of the hot-rolled strip or strip 55 Mechanical property of the hot-rolled strip or strip

Claims

1. Method for operating a hot strip production plant for producing a hot strip (10), the hot strip production plant comprising - a hot-rolling device for hot rolling the hot strip (10) from metal hot-rolling stock; - a coiler for winding the hot strip (10) onto a coil; and - at least one dynamic temperature control element, the method comprising the following method steps: - hot rolling the hot strip (10) from the metal hot-rolling stock using the hot-rolling device; - controlling the temperature of the metal hot-rolling stock and / or the hot strip (10) using the dynamic temperature control element; and - winding the hot strip (10) to form the coil; the method being characterized in that the temperature control of the metal hot-rolling stock and / or the hot strip (10) is controlled in an open-loop or closed-loop manner by means of the dynamic temperature control element such that the hot strip (10) has a varying temperature profile (33) in a longitudinal extent direction (14) before winding, the varying temperature profile (33) having a minimum temperature (40) and a maximum temperature (42).

2. Method according to claim 1, characterized in that the hot strip production plant comprises a heating device for heating and / or homogenizing the metal hot-rolling stock, the method comprising the method step of: - heating and / or homogenizing the metal hot-rolling stock using the heating device.

3. Method according to either of claims 1 and 2, characterized in that the maximum temperature (42) is greater than or equal to 1% higher than the minimum temperature (40), preferably greater than or equal to 2% and particularly preferably greater than or equal to 5%.

4. Method according to any of the preceding claims, characterized in that the maximum temperature (42) is greater than or equal to 5°C higher than the minimum temperature (40), preferably greater than or equal to 10°C and particularly preferably greater than or equal to 25°C.

5. Method according to any of the preceding claims, characterized in that the varying temperature profile (33) has a continuous profile, in particular a continuous profile over a length of greater than or equal to 50% of the metal hot-rolling stock and / or the hot strip (10), preferably over a length of greater than or equal to 95% or over a length of greater than or equal to 98% and particularly preferably over the entire length.

6. Method according to any of the preceding claims, characterized in that the temperature of the metal hot-rolling stock and / or the hot strip (10) is controlled over a length of greater than or equal to 95% of the metal hot-rolling stock and / or the hot strip (10), preferably over a length of greater than or equal to 97.5% or over a length of greater than or equal to 99% and particularly preferably over the entire length.

7. Method according to any of the preceding claims, characterized in that the varying temperature profile (33) has, at least in some regions, a temperature difference per 1 m length of the hot strip (10) and per 1 mm thickness of the hot strip (10) of greater than or equal to 0.1 K / (m * mm), preferably of greater than or equal to 0.2 K / (m * mm) or of greater than or equal to 0.4 K / (m * mm) and particularly preferably of greater than or equal to 0.8 K / (m * mm).

8. Method according to any of claims 1 to 7, characterized in that the maximum temperature (42) is located at one end of the hot strip (10) and the minimum temperature (40) is located in a central region of the hot strip (10).

9. Method according to any of claims 1 to 7, characterized in that the minimum temperature (40) is located at one end of the hot strip (10) and the maximum temperature (42) is located in a central region of the hot strip (10).

10. Method according to any of claims 1 to 7, characterized in that the temperature profile (33) has at least two or at least three peaks (44) away from the ends (16) of the hot strip (10).

11. Method according to any of claims 1 to 7, characterized in that the maximum temperature (42) and the minimum temperature (40) are located at opposite ends (16) of the hot strip (10).

12. Method according to any of the preceding claims, characterized in that the dynamic temperature control element comprises a cooling device, in particular a laminar cooling device and / or a transfer bar cooling system and / or a compact cooling system comprising coolant nozzles for discharging a coolant and / or an inter-stand cooling system.

13. Method according to any of the preceding claims, characterized in that the dynamic temperature control element comprises a heater, in particular an inductive heater.

14. Method according to any of the preceding claims, characterized in that the dynamic temperature control element has a nominal power density operatively connected to the hot strip (10) of greater than or equal to 2·105 W / m2, preferably of greater than or equal to 5·105 W / m2 and particularly of greater than or equal to 1.106 W / m2.

15. Method according to any of the preceding claims, characterized in that a dynamic temperature control element is arranged between the hot-rolling device and the coiler.

16. Method according to any of the preceding claims, characterized in that a dynamic temperature control element is arranged between the heating device and an outlet end of the hot-rolling device.

17. Method according to any of the preceding claims, characterized by the following steps: - detecting a mechanical property of the produced hot strip (10), in particular using an IMPOC (impulse magnetic process online controller); and - deriving a necessary open-loop or closed-loop control specification for the dynamic temperature control element for subsequent metal hot-rolling stock and / or for a subsequent hot strip (10).

18. Method according to any of the preceding claims, characterized in that the open-loop or closed-loop control by the dynamic temperature control element is carried out using a process model, in particular using a non-linear process model.

19. Method according to claim 18, characterized in that the process model comprises physical and / or chemical modeling, in particular metallurgical modeling.

20. Method according to either of claims 18 and 19, characterized in that the process model comprises a self-learning process model.

21. Method according to any of the preceding claims, characterized in that, for the purposes of the open-loop or closed-loop control by the dynamic temperature control element, data from a database can be used, in particular data comprising metallurgical information and / or process planning information, in particular data relating to a previous process, the current process and / or a downstream processing process.

22. Method according to any of the preceding claims, characterized in that, for the purposes of the open-loop or closed-loop control by the dynamic temperature control element, values of a measured variable can be used, in particular a temperature measured variable, a metallurgical measured variable, a microstructure component variable, a material property variable, a metal structure variable, a process variable and / or a geometry variable.

23. Hot strip production plant for producing a hot strip (10), comprising: - a hot-rolling device for hot rolling the hot strip (10) from metal hot-rolling stock; - at least one dynamic temperature control element; - a coiler for winding the hot strip (10) onto a coil; and - a control apparatus which is data-coupled to the dynamic temperature control element for the transmission of control signals, characterized in that the control apparatus is configured to carry out a method according to any of claims 1 to 22.

24. Hot strip production plant according to claim 23, characterized in that the hot strip production plant comprises a heating device for heating and / or homogenizing the metal hot-rolling stock.

25. Hot strip production plant according to either of claims 23 and 24, characterized in that the hot strip production plant comprises a measuring instrument for detecting a measured variable, the measuring instrument being data-coupled to the control apparatus.

26. Computer program product comprising program code means which cause the hot strip production plant according to any of claims 23 to 25 to carry out the steps of a method according to any of claims 1 to 22 when the computer program product is executed on the control apparatus of the hot strip production plant.