Method for operating a hot strip production plant, computer program product, and hot strip production plant for manufacturing a hot strip

Abstract

The invention relates to a method for operating a hot strip production plant for manufacturing a hot strip (10), comprising the following method steps: • - hot rolling the hot strip (10) from a metal hot-rolling stock by means of a hot rolling device; • - controlling the temperature of the hot strip (10); and • - winding the hot strip up into a coil; wherein the temperature control of the hot strip (10) is open-loop or closed-loop controlled by means of a dynamic temperature adjusting element, in such a way that before the hot strip (10) is wound up, it has a variable temperature profile (33) in a direction of longitudinal extent of the hot strip.

Description

[0001] METHOD FOR OPERATING A HOT STRIP PRODUCTION PLANT COMPUTER PROGRAM PRODUCT AND HOT STRIP PRODUCTION PLANT FOR PRODUCING A HOT STRIP

[0002] The present invention relates to a method for operating a hot strip production plant for producing a hot strip. Furthermore, the present invention relates to a hot strip production plant for producing a hot strip.

[0003] Hot strip production plants known in the prior art heat a metallic hot-rolled stock, in particular a slab, using a gas-fired furnace, in particular a walking-beam furnace. After hot rolling into a hot strip, the hot strip is cooled using a cooling device, in particular a laminar cooling device, and wound into a coil.

[0004] 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 length direction, in the width direction and in the thickness direction.

[0005] However, this objective can only be achieved to a limited extent because, among other things, local temperature inhomogeneities can occur during heating of the metallic hot-rolled stock in the furnace due to the contact surfaces of the slabs within the furnace. The reason for the aforementioned objective of maintaining the most constant temperature possible for the hot-rolled strip before coiling is to achieve the most homogeneous material properties possible for the hot-rolled strip before coiling.

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

[0007] The invention is based on the object of providing an improvement or an alternative to the prior art.

[0008] According to a first aspect of the invention, the object is achieved by a method for operating a hot strip production plant for producing a hot strip, wherein the hot strip production plant comprises a hot rolling device for hot rolling the hot strip from the metallic hot-rolled stock; a reel for winding the hot strip onto a coil; and at least one dynamic temperature control element; wherein the method comprises the following method steps:

[0009] Hot rolling of the hot strip from the metallic hot rolling stock using the hot rolling device;

[0010] Tempering the metallic hot-rolled stock and / or the hot strip with the dynamic temperature actuator; and winding the hot strip into the coil; wherein the tempering of the metallic hot-rolled stock and / or the hot strip is controlled or regulated by means of the dynamic temperature actuator such that the hot strip has a varying temperature profile in a longitudinal direction prior to winding the hot strip, wherein the varying temperature profile has a minimum temperature and a maximum temperature.

[0011] It is understood that the sequence of the method steps described above may also occur in a different order without departing from the aspect of the invention described here.

[0012] Preferably, the hot strip production plant may comprise a heating device for heating and / or homogenizing the metallic hot rolled stock, wherein the method may comprise the preferred method step:

[0013] Heating and / or homogenizing the metallic hot-rolled stock with the heating device.

[0014] 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, particularly if the metal contains an iron and a carbon content and can therefore also be referred to as steel.

[0015] The course of the phase transformation of steel influences the microstructure of steel, in particular the ferrite content and / or the pearlite content and / or the bainite content and / or the martensite content and / or the austenite content of the steel microstructure. The microstructure of steel, in turn, influences the properties of steel. As a rule, a locally deviating cooling curve of steel leads to correspondingly locally different material properties.

[0016] For example, a lower pearlite content can be achieved by rapid cooling and lead to lower hardness and / or better formability. Alternatively, a slower

[0017] Cooling leads to greater hardness.

[0018] In other words, there is a causal relationship between the properties of a metallic strip and the temperature control during its production.

[0019] The hot-rolled strip is generally coiled at a temperature at which the structural transformation of the metal is not yet complete. The temperature at which the hot-rolled strip is coiled is typically in the range between 300 °C and 750 °C. The above temperature range is merely an example and is intended to clarify the typical temperature range. The exact temperature at which the hot-rolled strip is coiled depends on the alloy and / or the quality of the hot-rolled strip.

[0020] It has been shown that the production of hot-rolled strip using state-of-the-art hot-rolled strip production plants leads to inhomogeneity in the material properties. Among other things, the cooling of the hot-rolled strip in the coil results in a change in the material properties of the hot-rolled strip, particularly in the longitudinal direction of the hot-rolled strip, since the outer and inner coils cool down faster than the middle coils. This inhomogeneity in the material properties occurs even when the temperature of the hot-rolled strip is as constant as technically possible before it is coiled.

[0021] Even a subsequent further treatment of the initially wound hot strip in a strip treatment plant, in particular with a continuous galvanizing line, leads, even if the strip is annealed in the strip treatment plant, to a further treated strip with different material properties, which - as has now been recognized - can be attributed, among other things, to the inhomogeneous cooling behavior of the hot strip in the coil and thus the precipitation behavior influencing the microstructure and / or the grain growth influencing the microstructure and / or the phase components influencing the microstructure.

[0022] Deviating from the previously known objective of winding the produced hot strip at a temperature that is as constant as possible, it is now specifically proposed here to temper the hot strip during its production before winding it into a coil in such a way that the hot strip has a varying temperature profile before winding.

[0023] “Tempering” is understood to mean the adjustment of the temperature of the metallic hot-rolled stock and / or the hot strip by means of at least one dynamic temperature control element, in particular the adjustment of the temperature of the metallic hot-rolled stock and / or the hot strip in the longitudinal direction of the metallic hot-rolled stock and / or the hot strip, in particular the adjustment of the temperature of the metallic hot-rolled stock and / or the hot strip as a function of a coordinate in the longitudinal direction of the metallic stock. In other words, the metallic hot-rolled stock and / or the hot strip can be tempered in such a way that a temperature varying in the longitudinal direction of the metallic hot-rolled stock and / or the hot strip is set in the metallic hot-rolled stock and / or the hot strip. In this way, a different temperature that is variable over the length of the metallic hot-rolled stock and / or the hot strip can be set.

[0024] A "dynamic temperature actuator" is understood to mean a device which is designed to generate a varying temperature profile which corresponds to a varying temperature profile of the hot strip in front of the coiler per 1 m length of the hot strip and per 1 mm thickness of the hot strip of 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 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). In particular, the dynamic temperature actuator can achieve the above values ​​for the varying temperature profile by heating and / or cooling.

[0025] Tempering makes it possible to set different and / or variable temperatures over the length of the metallic hot-rolled stock and / or the hot-rolled strip.

[0026] To achieve a variable temperature distribution in a hot strip, tempering can be performed before hot rolling, i.e., in conjunction with a metallic hot-rolled stock, and / or between two rolling stands and / or after hot rolling, i.e., in conjunction with a hot strip. Since the result of tempering is always retained in the hot-rolled hot strip, tempering of a hot strip, within the scope of this application, can be understood as tempering before hot rolling, during hot rolling, and / or after hot rolling.

[0027] Tempering can be understood as a partial or complete cooling of the metallic hot-rolled stock and / or the hot strip and / or a partial maintenance of the temperature of the metallic hot-rolled stock and / or the hot strip and / or a partial or complete heating of the metallic hot-rolled stock and / or the hot strip.

[0028] This ensures that the microstructure of the hot-rolled strip, and thus also 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.

[0029] In this context, a "varying temperature profile" is understood to mean a temperature profile which 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 has a continuous connection between at least one maximum value and one minimum value for a designated temperature and / or a high point and a low point for a designated temperature of the hot strip before coiling.

[0030] It was shown that with a varying temperature profile before the hot strip is coiled, the precipitation behavior and / or the grain growth and / or different phase proportions of the hot strip can be changed locally in such a way that this targeted change, together with another unavoidable or deliberately induced local change in the precipitation behavior and / or the grain growth and / or the phase proportions as a result of 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.

[0031] In this case, “material properties” can be understood to mean 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 proportions (austenite, ferrite, pearlite, bainite, martensite), electrical properties and / or core losses or the like. 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 coil cool down faster than the center of the coil.

[0032] A "heating device" is understood to mean a device which is configured for heating and / or homogenizing and / or annealing and / or maintaining the temperature of a metallic hot-rolled stock. In other words, a heating device can be configured to condition and / or prepare a metallic hot-rolled stock for processing by means of a hot-rolling device. In this way, the temperature in a metallic hot-rolled stock can be adjusted for hot rolling by means of a heating device. A heating device can thus be understood as a link between an upstream process step and a hot-rolling device.

[0033] 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.

[0034] According to a first 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.

[0035] According to a second variant, a metallic hot-rolled stock can be transferred directly with initial heat from a casting device for metallic hot-rolled stock to a heating device, where it can be heated to a hot-rolling temperature. According to a third variant, a metallic hot-rolled stock can be annealed by a heating device at a constant temperature.

[0036] According to a fourth variant, a temperature distribution in a metallic rolling stock can be homogenized using a heating device. In other words, a temperature distribution in a metallic hot-rolled stock can be equalized within a heating device.

[0037] It should be expressly mentioned that the above variants do not 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.

[0038] It is understood that a plurality of heating devices can also be used to heat the metallic hot-rolled stock without departing from the present aspect of the invention.

[0039] Preferably, it should also be considered that the process proposed here can be carried out on a Steckei mill. Therefore, the term "hot strip production plant" can also be understood to mean a Steckei mill.

[0040] 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 of the temperature profile 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, 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, preferably greater than or equal to 6% and particularly preferably greater than or equal to 7%.

[0041] Optionally, the maximum temperature is 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%.

[0042] 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, preferably greater than or equal to 20 ° C and particularly preferably greater than or equal to 30 ° C.

[0043] 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.

[0044] It has been shown that to achieve the proposed varying temperature profile of the hot strip in the longitudinal direction, a dynamic temperature actuator is required. With the dynamic temperature actuator, a higher temperature dynamic can be achieved than with a heating device of the hot strip production plant, in particular with a gas-fired heating device of the hot strip production plant. It is understood that a plurality of dynamic temperature actuators can also be used to achieve the object, in particular a cooling device and an inductive heating device.

[0045] The temperature control of the hot strip prior to coiling is carried out using a control or regulation system that is data-coupled to the dynamic temperature control element. The regulation system can comprise a continuous linear controller, in particular a PD controller or a PID controller.

[0046] A dynamic temperature controller can have a cooling device, in particular a laminar cooling device and / or a transfer bar cooling system (also TBC for transfer bar cooling) and / or a compact cooling system having coolant nozzles for allowing a coolant to escape and / or an inter-stand cooling system. A cooling device can be arranged between the hot rolling device and the coiler. Cooling devices are known to have a cooling rate of 50 K / s, so that the hot strip can be cooled by means of such a cooling device from a thickness-average temperature of 1,150 K to a thickness-average temperature of 650 K in a cooling time of 10 s.

[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 demonstrated—sufficiently influence the precipitation behavior and / or grain growth and / or different phase fractions corresponding to the overall objective. In this respect, a control or regulation system can be coupled to a cooling device and adjust the cooling device accordingly with the objective of the varying temperature profile proposed here.

[0048] Optionally, a dynamic temperature control element may comprise a heating device, in particular an inductive heating device. An inductive heating device may preferably be arranged upstream of the coiler.

[0049] Such a heating device can have a nominal power density in

[0050] Effective connection to the hot strip of greater than or equal to 2 - 10 5 W / m 2 preferably greater than or equal to 5 - 10 5 W / m 2 and especially greater than or equal to 1 - 10 6 W / m 2 . It was shown that the precipitation behavior and / or the grain growth and / or different phase fractions can be sufficiently influenced according to the overall objective with the nominal power densities proposed above for a heating device.

[0051] A heating device can be arranged in function as a component of a dynamic temperature control element between the hot rolling device and the coiler, in particular in front of or behind a cooling device.

[0052] Furthermore, a heating device functioning as a component of a dynamic temperature control element can preferably be arranged between the heating device and an outlet end of the hot rolling device, in particular in front of one of the rolling stands of the hot rolling device.

[0053] Also preferably, a heating device functioning as a component of a dynamic temperature control element can be arranged between two rolling stands of the hot rolling device.

[0054] It is understood that a dynamic temperature control element cannot be understood as a reel heating device which is designed to control the temperature of a coil, such as a reel heating device known from a Steckei Mill.

[0055] An "outlet end" is understood to be the side of a hot rolling device at which the hot strip is designated to run out of the hot rolling device. In other words, this means the end of the hot rolling device which, with regard to a designated material flow of the hot strip on the

[0056] side of the coiler. Optionally, the tempering of the metallic hot-rolled stock and / or the hot strip takes place 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.

[0057] Here, it is proposed to also temper significant areas of a strip head of a hot strip and / or a strip end of a hot strip, in particular by continuously varying the temperature in the hot strip. This advantageously allows a strip head and / or a strip end to be included in the present aspect, so that the advantages described here can also extend to the strip head and / or strip end.

[0058] Particularly homogeneous material properties for the finished product and / or for the cooled, further processed strip, in particular cold-rolled strip, and / or for the cooled hot-rolled 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 stock and / or the hot-rolled 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 stock and / or the hot-rolled strip.

[0059] In this case, “continuous progression” means a continuous progression in the mathematical sense.

[0060] Furthermore, particularly homogeneous material properties in the sense described above can be achieved if the tempering of the metallic hot-rolled stock and / or the hot strip by means of the dynamic temperature control element takes place 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.

[0061] Particularly preferably, the varying temperature profile has, at least in some regions, a temperature difference per 1 m length of the hot strip and per 1 mm thickness of the hot strip of 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 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). In particular, the above values ​​correspond to a varying temperature profile of the hot strip in front of the coiler, regardless of the arrangement of the dynamic temperature actuator within the hot strip production plant.

[0062] By means of the above values ​​for the variation of the varying temperature profile using the dynamic temperature control element, particularly advantageous temperature gradients can be achieved in the above sense, which in combination with the cooling behavior of the hot strip and / or compensating temperature differences by storing the metallic hot-rolled stock in a heating device and / or the subsequent processing of the cold strip lead to particularly advantageous material properties, in particular in the sense described above.

[0063] 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.

[0064] Preferably, for the varying temperature profile at each

[0065] A maximum temperature must be provided at the end of the hot strip and a minimum temperature in a middle area of ​​the hot strip.

[0066] Furthermore, for the varying temperature profile, a minimum temperature and a maximum temperature in a central region of the hot strip can be provided at each end of the hot strip.

[0067] The varying, continuous temperature profile can have a bathtub function, the profile of which is designed analogously to the wall profile of a bathtub in cross-section, with the maximum temperatures being found at the respective end of the profile and the minimum temperature in the middle area.

[0068] The middle area is arranged between the ends of the hot strip in the longitudinal direction of the hot strip.

[0069] It has been shown that a wound hot strip cools down faster, particularly at its outer turns, than in a central area, with the inner turns also cooling down faster than the inner area.

[0070] It was found that the here proposed varying temperature profile of the hot strip before coiling 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 down on the coil.

[0071] Furthermore, at least two or at least three high points away from the ends of the hot strip, i.e. in the middle region of the hot strip, are optionally provided for the varying temperature profile. When the metallic hot rolled stock is heated using the heating device, in particular using a walking beam heating device, the contact surfaces of the metallic hot rolled stock can locally lead to a lower temperature of the metallic rolled stock and, after hot rolling, also of the hot strip. This can lead to locally inhomogeneous precipitation behavior and / or grain growth and / or phase proportions, an associated locally different microstructure and thus also to different material properties during the entire temperature control process up to the coiling of the hot strip or until the hot strip has completely cooled down to ambient temperature.

[0072] Here, it is proposed to heat the metallic hot-rolled stock and / or the hot-rolled strip more intensively at the points corresponding to the inhomogeneous temperature by the heating device, so that the varying temperature profile has correspondingly arranged high points.

[0073] It was shown that in this way the precipitation behavior and / or the 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.

[0074] Some strip processing plants operate continuously, with a plurality of wound hot strips being joined together at the input side and continuously processed by the strip processing plant.

[0075] Due to production planning, it may be necessary to arrange strips of different material grades adjacent to each other, join them together, and process them immediately one after the other. This may result in material A with an annealing temperature of 720 °C having to be produced directly before material B with an annealing temperature of 750 °C. Since the heating device in a strip processing line also has an inertia, a zone may arise in the transition that cannot be treated with the ideal annealing temperature.

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

[0077] As has been shown, this makes it possible to trim the precipitation in the hot strip and / or the grain growth and / or the formation of different phase fractions in such a way that, when the hot strip is further processed in a strip processing plant at successive different annealing temperatures of successively treated material grades, a strip with largely homogeneous material properties can be produced.

[0078] Particularly good results can be achieved if the procedure includes the following steps:

[0079] Recording a mechanical property of the hot strip produced , in particular with an IMPOC ( Impulse Magnetic Process Online Controller ) ; and

[0080] Deriving a necessary control or regulation specification for the dynamic temperature actuator for a subsequent metallic hot rolling stock and / or for a subsequent hot strip.

[0081] This allows data, in particular data relating to at least one material property, of a hot strip that has already been produced to be used to optimize the control and / or regulation of the dynamic temperature actuator for a hot strip that is still to be produced. In particular, the measured data achieved in this way can be compared with the desired target data. If differences are identified, a change to a control and / or regulation specification can be derived, in particular such that an existing deviation in at least one mechanical property is reduced to a minimum or avoided.

[0082] Preferably, the control or regulation of the dynamic temperature actuator is carried out using a process model, in particular using a non-linear process model. The control of the dynamic temperature actuator can be carried out using a model-based controller, in particular using a model-based controller based on a non-linear process model.

[0083] Precise and reliable control or regulation can be advantageous in improving the dynamic behavior of thermal processes. With regard to temperature-dependent and material-dependent dynamic precipitation behavior and / or dynamic grain growth and / or the dynamic formation of different phase fractions, mechanisms influencing the precipitation behavior and / or dynamic grain growth and / or the dynamic formation of different phase fractions can be used to construct a process model that can be used as a substitute system in the context of control or regulation.

[0084] Such a process model can contain linear or non-linear model components and be supported by data, in particular by measurement data.

[0085] A process model can be modeled continuously over time using differential equations to reproduce the dynamics. Regardless of whether the process model is used for open-loop or closed-loop control, it can represent the precipitation process considered here and / or the grain size formation process and / or the formation process of different phase fractions with better accuracy than is possible with a linear control or using a continuous linear controller, in particular a P controller, a PD controller or a PID controller. In particular, the process model, in direct comparison to a continuous linear controller, can enable cross-coupling of different variables as well as explicit compliance with process-related boundary conditions, since continuous linear controllers are determined only by a conservative choice of setting parameters that is suitable in the optimal case.

[0086] As a result, the use of a process model allows the control or regulation of the tempering of the metallic rolling stock and / or the hot strip in the direction of an advantageous varying temperature profile.

[0087] The use of a process model in the context of controlling the temperature of the metallic rolled stock and / or the hot strip also allows for model-predictive control, as the process model can also be used as a prediction model. In this way, with appropriate 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 such that the cooled hot strip exhibits homogeneous material properties.

[0088] Particularly preferably, the process model can also include the further treatment 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 further treated into a strip using a strip processing plant can have the desired, most homogeneous material properties possible after it has completely cooled down to the ambient temperature.

[0089] 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.

[0090] Particularly advantageous, homogeneous material properties can also be achieved if the process model includes a physical and / or chemical model, in particular a metallurgical model.

[0091] Optionally, data from a database can be used to control or regulate the dynamic temperature actuator, in particular data comprising metallurgical information and / or process planning information.

[0092] This makes it possible, among other things, to achieve an empirical process model that is comparatively easy to build and / or adapt.

[0093] The link to a database can also simplify the control or regulation of the dynamic temperature actuator, so that, among other things, a 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.

[0094] Furthermore, a semi-empirical process model can be considered, which can use data from a database or a model based on physical and / or chemical principles, particularly metallurgical ones. Data can be data from the current process, a previous process, and / or a downstream processing process.

[0095] Particularly advantageously, values ​​of at least one measured variable can be used to control or regulate the dynamic temperature control element, 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 variable can be understood as, 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 value allows, among other things, an 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 the consideration of cross-coupling between measured variables within the process model.

[0099] Consideration of 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, especially 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, in particular using machine learning, whereby the mapping quality and the model depth of the process model can be continuously developed in a comparatively simple way.

[0101] For some variables, in addition to measured values ​​of these variables, setpoints can also be used 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 coiler temperature, a cooling strategy, an intermediate strip thickness, a cold forming degree, an annealing temperature and / or a cooling stop temperature after annealing.

[0102] When measuring microstructural components on the hot-rolled strip, particularly before the hot-rolled strip is wound into a coil, particularly using a microstructure sensor, particular attention should be paid to measuring the austenite and / or ferrite content. This advantageously allows a prediction of the mechanical properties to be achieved. This prediction can be used, among other things, for controlling or regulating the tempering of the metallic hot-rolled stock and / or the hot-rolled strip.

[0103] A determination of material values ​​in the laboratory can also be regarded as 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, more 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. Between the segments, continuous or continuous and differentiable modeling for a target value can take place. Optionally, a loss of hot-rolled strip in the form of scrap accumulating at the head end and / or at the foot end can be taken into account.

[0105] For the quality release of the hot strip it is traditionally required that the material quality in the longitudinal direction of the hot strip does not leave a defined tolerance range, whereby the hot strip is 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 strip. In this case it is therefore proposed to use a measuring technology for the quality release for the release (e.g. Impulse Magnetic Process Online Controller (IMPOC)) which is sensitive to the desired material property, or to consider a modeled value for the desired material property over the strip length, which must be within the specified tolerance.

[0106] Due to a material change in a hot strip production line (casting and rolling line) linked to a casting machine, the chemical analysis within a hot strip may vary along its length. In conventional homogeneous processing, this leads to inhomogeneous material properties. It is now proposed to also record the material size of the hot strip in sectors or continuously in the longitudinal direction, so that more homogeneous material properties can be achieved with the proposed method and by modeling the material size, particularly in the process model.

[0107] It is understood that the above components of a process model can also be advantageously combined with one another. According to a second aspect of the invention, the object is achieved by 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 when the computer program product is executed on a computing device.

[0108] It is understood that the above-explained advantages of a method for operating a hot strip production plant for producing a hot strip according to the first aspect of the invention 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.

[0109] It should be expressly pointed out that the subject matter of the second aspect can be advantageously combined with the subject matter of the preceding aspect of the invention, both individually or cumulatively in any combination.

[0110] According to a third aspect of the invention, the object is achieved by a hot strip production plant for producing a hot strip, comprising: a hot rolling device for hot rolling the hot strip from a metallic hot-rolled stock; at least one dynamic temperature actuator; a reel for winding the hot strip onto a coil; and a control device which is data-coupled to the dynamic temperature actuator for transmitting control signals; wherein the control device is designed to carry out a method according to the first aspect of the invention.

[0111] It is understood that the above-explained advantages of a method for operating a hot strip production plant for producing a hot strip according to the first aspect of the invention extend directly to a hot strip production plant for producing a hot strip having a control device suitable for carrying out a method according to the first aspect of the invention.

[0112] Preferably, the hot strip production plant comprises a heating device for heating and / or homogenizing the metallic hot rolled stock.

[0113] Optionally, the hot strip production plant has a measuring device for recording a measured variable, wherein the measuring device is data-coupled to the control device, in particular an IMPOC (Impulse Magnetic Process Online Controller).

[0114] It has already been explained above that the use of measured variables for controlling or regulating the temperature of the metallic hot-rolled stock and / or the hot strip can be advantageous. It is therefore understood that these advantages also extend to a hot-strip production plant that has at least one measuring device for detecting this at least one measured variable, wherein the at least one measuring device is data-coupled to the control device for transmitting the values ​​of the measured variable.

[0115] It should be expressly pointed out that the subject matter of the third aspect can be advantageously combined with the subject matters of the preceding aspects of the invention, both individually or cumulatively in any desired combination.

[0116] The following should be explained conceptually:

[0117] First of all, it should be expressly pointed out that in the context of this patent application, indefinite articles and numerical expressions such as "one", "two", etc., are generally to be understood as "at least" expressions, i.e. as "at least one...", "at least two...", etc., unless it is expressly clear from the respective context or it is obvious or technically necessary for the person skilled in the art that only "exactly one...", "exactly two...", etc. can be meant.

[0118] In the context of this patent application, the expression "in particular" should always be understood as introducing an optional, preferred feature. The expression should not be understood as "and indeed" or "namely".

[0119] Further advantages, details, and features of the invention will become apparent from the following exemplary embodiments. In detail:

[0120] Figure 1: schematically shows temperature profiles (a), (c) and a corresponding material property (b), (d) for a hot strip according to a first embodiment;

[0121] Figure 2: schematically shows temperature profiles (a), (c) and a corresponding material property (b), (d) for a hot-rolled strip according to a second embodiment; and

[0122] Figure 3: schematic temperature curves (a), (c) and a corresponding material property (b), (d) for a hot strip according to a third embodiment.

[0123] In the following description, identical reference numerals designate identical components or identical features, so that a description of a component made with reference to one figure also applies to the other figures, thus avoiding repetitive description. Furthermore, individual features described in connection with one embodiment can also be used separately in other embodiments. A hot-rolled strip 10 (not explicitly shown) has a longitudinal extension 12, a longitudinal extension direction 14, and two ends 16.

[0124] Fig. 1 to 3 each show, in a schematic illustration, two temperature profiles 30, 31, 33 in the figure sections (a) and (c) as well as the figure sections (b) and (d) in a schematic illustration of a material property 50, 55 corresponding to the respective temperature profile 30, 31, 33, in particular a tensile strength of the hot strip 10.

[0125] The corresponding figure sections (a) and

[0126] (b) , i.e. the material property 55 in the figure section (b) 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) to the temperature profile 33 in the figure section

[0127] (c) .

[0128] The figure sections (a) and (b) are each known, while the figure sections (c) and (d) are according to the invention.

[0129] It should be expressly pointed out that the embodiments one to three according to Figs. 1 to 3 can also be combined cumulatively with each other as desired.

[0130] For the first embodiment in Fig. 1, it is known that a hot strip production plant has the objective of maintaining a temperature 30 that is as constant as possible over the longitudinal extent 12 of the hot strip 10.

[0131] However, after coiling, the hot-rolled strip 10 cools at different rates along its longitudinal extension 12. While the outer coil and the inner coil cool comparatively quickly, the heat accumulates inside the coil, so that cooling inside the coil proceeds more slowly.

[0132] 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 has an inhomogeneous course of a material property 55 after cooling.

[0133] Here, it is proposed to design the tempering of the hot strip 10 before coiling in such a way that a varying temperature profile 33 is established in the hot strip 10. The varying temperature profile 33 has a bathtub function, with a minimum temperature 40 in a central region and a maximum temperature 42 at the ends 16 of the hot strip 10.

[0134] Tests 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, being able to have a homogeneous profile 50 of a material property, wherein the profile 50 of the material property has an improved homogeneity, in particular in comparison to the known profile 55 of the material property.

[0135] The second embodiment according to Fig. 2 shows an inhomogeneity of a material property 55 as a result of a temperature profile 31 upon exiting the heating device of a metallic hot-rolled stock, which will subsequently be hot-rolled into a hot strip 10 in the process. Since this temperature distribution 31 only expands longitudinally during hot rolling, the temperature profile 31 has already been transferred to a hot strip 10 in the figure section (a).

[0136] The temperature distribution 31 has three low points which correspond to the beams of a walking beam heating device, by means of which the metallic hot-rolled stock in the heating device has not been heated homogeneously.

[0137] Here, it is proposed to design the tempering of the hot strip 10 before coiling in such a way that a varying temperature profile 33 is established in the hot strip 10. The varying temperature profile 33 has three high points 44 corresponding to the low points of the temperature profile 31.

[0138] Tests have shown that such a varying temperature profile 33 trimmed with a dynamic temperature control element can lead to the hot strip 10 having a homogeneous profile 50 of a material property after cooling, wherein the profile 50 of the material property has an improved homogeneity, in particular in comparison to the known profile 55 of the material property.

[0139] The third embodiment according to Fig. 3 shows an inhomogeneity of a material property 55 after the strip 20 leaves a continuous strip processing plant. During the production of the hot strip 10, this was produced according to the temperature profile 30 in the hot strip production plant before coiling.

[0140] However, the temperature control of the heating device of the strip treatment plant in this case leads to the curve 55 of the material property after the strip 20 leaves the strip treatment plant, since the heating device of the treatment plant was adjusted at one end of the strip to a different temperature required for the quality of an adjacent strip. The dynamics of this temperature change in the continuously operated strip treatment plant can be seen in the curve of the material property 55.

[0141] It is now proposed here to design the temperature control of the hot strip 10 before coiling in such a way that a varying temperature profile 33 is established in the hot strip 10. The varying temperature profile 33 has 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, wherein the temperature profile in the central region of the hot strip 10 corresponds to the dynamics of the heating device of the downstream continuous strip processing plant.

[0142] Tests have shown that such a trimmed, varying temperature profile 33 can lead to the strip 20 having a homogeneous profile 50 of a material property after further treatment by means of the strip treatment plant, wherein the profile 50 of the material property has an improved homogeneity, in particular in comparison to the known profile 55 of the material property.

[0143] List of reference symbols

[0144] 10 hot-rolled strip

[0145] 12 Longitudinal extension of the hot strip 14 Longitudinal extension direction of the hot strip

[0146] 16 ends of the hot strip

[0147] 20 volumes

[0148] 30 constant temperature curve before the reel

[0149] 31 Temperature curve when leaving the heating device

[0150] 33 varying temperature profile

[0151] 40 minimum temperature

[0152] 42 Maximum temperature

[0153] 44 High point 50 Mechanical property of the hot-rolled strip or strip

[0154] 55 Mechanical properties of the hot-rolled strip or strip

Claims

Patent claims 1. A method for operating a hot strip production plant for producing a hot strip (10), wherein the hot strip production plant has a hot rolling device for hot rolling the hot strip (10) from a metallic hot-rolled stock; a reel for winding the hot strip (10) onto a coil; and at least one dynamic temperature control element; wherein the method comprises the following method steps: hot rolling the hot strip (10) from the metallic hot-rolled stock using the hot rolling device; Tempering the metallic hot-rolled stock and / or the hot-rolled strip (10) with the dynamic temperature control element; and winding the hot-rolled strip (10) into the coil; wherein the method is characterized in that the tempering of the metallic hot-rolled stock and / or the hot-rolled strip (10) is controlled or regulated by means of the dynamic temperature control element such that the hot-rolled strip (10) has a varying temperature profile (33) in a longitudinal direction (14) before winding, wherein the varying temperature profile (33) has a minimum temperature (40) and a maximum temperature (42).

2. Method according to claim 1, characterized in that the hot strip production plant has a heating device for heating and / or homogenizing the metallic hot rolled stock, the method comprising the method step: Heating and / or homogenizing the metallic hot-rolled material with the heating device.

3. Method according to one of claims 1 or 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 one 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 one 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 metallic hot-rolled 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 one of the preceding claims, characterized in that the tempering of the metallic hot-rolled stock and / or the hot strip (10) takes place over a length of greater than or equal to 95% of the metallic hot-rolled 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 one 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 greater than or equal to 0.8 K / (m * mm) .

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

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

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

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

12. Method according to one 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 device and / or a compact cooling device comprising coolant nozzles for discharging a coolant and / or an inter-stand cooling device.

13. Method according to one of the preceding claims, characterized in that the dynamic temperature control element has a heating device, in particular an inductive heating device.

14. Method according to one of the preceding claims, characterized in that the dynamic temperature control element has a nominal power density in operative connection to the hot strip (10) of greater than or equal to 2 -10 5 W / m 2 preferably greater than or equal to 5-10 5 W / m 2 and especially greater than or equal to 1-10 6 W / m 2 .

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

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

17. Method according to one of the preceding claims, characterized by the following steps: Detecting a mechanical property of the produced hot strip (10), in particular with an IMPOC (Impulse Magnetic Process Online Controller); and Deriving a necessary control or regulation specification for the dynamic temperature actuator for a subsequent metallic hot-rolled product and / or for a subsequent hot strip (10).

18. Method according to one of the preceding claims, characterized in that the control or regulation of the dynamic temperature actuator is carried out using a process model, in particular using a non-linear process model.

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

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

21. Method according to one of the preceding claims, characterized in that data from a database can be used to control or regulate the dynamic temperature actuator, in particular data comprising metallurgical information and / or process planning information, in particular data of a previous process, the current process and / or a downstream processing process.

22. Method according to one of the preceding claims, characterized in that values ​​of a measured variable can be used to control or regulate 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 geometry variable.

23. A computer program product comprising program code means suitable for carrying out the steps of a method according to any one of the preceding claims when the computer program product is executed on a computing device.

24. A hot strip production plant for producing a hot strip (10), comprising: a hot rolling device for hot rolling the hot strip (10) from a metallic hot-rolled stock; at least one dynamic temperature control element; a reel for winding the hot strip (10) onto a coil; and a control device which is data-coupled to the dynamic temperature actuator for transmitting control signals; characterized in that the control device is configured to carry out a method according to one of claims 1 to 22.

25. Hot strip production plant according to claim 24, characterized in that the hot strip production plant has a heating device for heating and / or homogenizing the metallic hot rolled stock. 26 . Hot strip production plant according to one of claims 24 or 25 , characterized in that the hot strip production plant has a measuring device for detecting a measured variable , the measuring device being data - coupled to the control device .

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