Rolling control device

Abstract

In the present invention, during rolling, a first actual results collection unit collects first exit-side sheet thickness measured values at a first management point of a rolling material, and rolling load measured values for each stand. During the rolling of the rolling material, a second actual results collection unit collects second exit-side temperature measured values at a second management point, which is farther toward the tail end side than the first management point. After the rolling of the rolling material, a first training unit trains a deformation resistance model, a rolling load model, and a mill elongation model on the basis of the first exit-side sheet thickness measured values and the rolling load measured values. After the rolling of the rolling material, a second training unit trains a temperature model on the basis of the second exit-side temperature measured values. Before rolling of the next material, a setting calculation unit calculates a roll gap setting value, a roll peripheral speed setting value, and a cooling water amount setting value, using the deformation resistance model, the rolling load model, and the mill elongation model that were trained by the first training unit, and the temperature model that was trained by the second training unit.

Description

Technical Field

[0001] The present disclosure relates to a rolling control device. In particular, the present disclosure relates to a rolling control device that controls the temperature and thickness of a rolled material on the output side of a finishing mill (finishing rolling mill).

Background Art

[0002] The quality requirements for rolled materials (hereinafter also referred to as "coils") rolled on a hot rolling line have become increasingly strict in recent years. The thickness of the rolled material on the output side of the finishing mill (hereinafter also referred to as the "output-side thickness"), which is one of the quality aspects, affects the dimensional accuracy during processing into the final product. Therefore, it is necessary to precisely control the output-side thickness. In addition, the temperature of the rolled material on the output side of the finishing mill (hereinafter also referred to as the "output-side temperature") affects the material properties such as the yield stress, tensile strength, and elongation of the rolled material. Therefore, it is also necessary to precisely control the output-side temperature.

[0003] FIG. 7 is a schematic diagram showing the configuration of a conventional rolling control device. This device includes a setting calculation unit (FSU) 110 that executes setting calculations before the rolled material reaches the finishing mill 4. The setting calculations are performed so that the measured values of the output-side thickness (FDH: Finisher Delivery Thickness) and the output-side temperature (FDT: Finisher Delivery Temperature) measured by a thickness gauge (hereinafter also referred to as the "output-side thickness gauge") 8 and a thermometer (hereinafter also referred to as the "output-side thermometer") 9 arranged on the output side of the finishing mill 4 match the respective target values. The roll gap setting value for each stand, the roll peripheral speed setting value (motor speed setting value), and the cooling water flow rate setting value of the cooling device (ISC) arranged between the stands are calculated. For this calculation, a prediction model consisting of a group of mathematical formulas for predicting the temperature, deformation resistance, rolling load, and mill elongation of the rolled material is used. The deformation resistance is the stress required to deform the rolled material. The mill elongation is the change in the roll gap due to the elastic deformation of the rolling rolls. The set values calculated in the setting calculations are set in various facilities on the hot rolling line.

[0004] When the rolled material heated in the heating furnace passes through the rough mill and reaches the finishing mill 4, rolling begins in the finishing mill 4. The rolled material is sequentially fed into each stand of the finishing mill 4, and when the leading edge of the rolled material exits the finishing mill, measurement of the exit plate thickness FDH and exit temperature FDT begins.

[0005] During rolling by the finishing mill 4, the feedback thickness control unit 117 executes a monitor AGC (Automatic Gage Control) that calculates the amount of change in the roll gap based on the FDH measurement value, and a gauge meter AGC (GM-AGC) that estimates the exit plate thickness of each stand based on the actual values ​​of the rolling load and roll gap and maintains the estimated plate thickness (gauge meter plate thickness) at a constant level. At the same time, the feedback temperature control unit 118 executes a feedback temperature control (FB-FDTC) that calculates the amount of change in the roll peripheral speed and cooling water flow rate of each stand based on the exit temperature measurement value. As a result, the exit plate thickness measurement value and the exit temperature measurement value are controlled to approach their respective target values. Such feedback control is disclosed, for example, in Patent Document 1 below.

[0006] Here, in the finishing mill 4, the leading edge of the rolled material is rolled before feedback control is performed. Therefore, the accuracy of the exit thickness FDH and exit temperature FDT of the leading edge of the rolled material depends solely on the set values ​​calculated by the setting calculation unit (FSU) 110. In the rolled material temperature control device disclosed in Patent Document 2 below, a convergence calculation method is used to improve the accuracy of the temperature model used in the setting calculation. That is, before the rolled material reaches the finishing mill, the exit temperature at the time when the calculation point (control point) on the rolled material reaches a predetermined position on the exit side of the finishing mill is calculated, and this calculated value is compared with the target exit temperature value. If the compared value is outside the acceptable range, the motor speed calculation value is corrected. Accordingly, the finishing mill entry temperature, the heat balance of the rolls, the heat balance between stands, etc. are recalculated (updated), and as a result, highly accurate temperature prediction values ​​can be used.

[0007] Incidentally, conventionally, a control point is set near the leading edge of the rolled material, and FDT measurements are collected when this control point is directly below the exit thermometer 9. A temperature model is then trained using the collected FDT measurements, and the trained values ​​are reflected in the setting calculations for the next rolled material (hereinafter also referred to as "next material"), thereby bringing the FDT measurements of the control point of the next material closer to the FDT target value. Furthermore, rolling load measurements are collected when the control point is directly below each stand, and FDH measurements are collected when the control point is directly below the exit thickness gauge 8. Models for deformation resistance, rolling load, and mill elongation at each stand are then trained using these measurements, and the trained values ​​are reflected in the setting calculations for the next material, thereby bringing the FDH measurements of the control point of the next material closer to the FDH target value. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent No. 3657750 [Patent Document 2] Japanese Patent Publication No. 2000-210708 [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] Incidentally, the temperature of the leading edge of the rolled material extracted from the heating furnace may become locally high (or low). In this case, as shown in Figure 8, the exit temperature FDT at the leading edge of the rolled material becomes higher (or lower) than the exit temperature FDT at the tail end (steady state). That is, a phenomenon occurs in which a sudden temperature change occurs at the leading edge of the rolled material, transitioning from a high-temperature (or low-temperature) area to a steady state. Such sudden temperature changes occur because the temperature difference between the surface and the interior of the rolled material increases due to the rapid heating of the rolled material in the heating zone of the furnace, or because sufficient time (furnace time) for the rolled material to be in the homogeneous zone inside the furnace cannot be secured. In recent years, there has been a tendency to shorten the furnace time in order to increase production volume by shortening the rolling interval (rolling pitch), making it virtually impossible to avoid the occurrence of sudden temperature changes.

[0010] When a sudden temperature change occurs at the leading edge of the rolled material, the following first and second learning methods can be considered as learning methods by the learning unit. In the first learning method, the high-temperature portion of the rolled material is designated as the control point (hereinafter referred to as "first control point") Mp1, and FDT and FDH measurement values ​​are collected when the first control point Mp1 is located directly below the exit thermometer 9 and the exit thickness gauge 8. Learning is performed using the collected measurement values. That is, the setting calculation unit 110 calculates various setting values ​​so that the FDT and FDH measurement values ​​at the first control point Mp1 match the target values. As a result, as shown by the dashed line L1 in Figure 3, the FDT measurement value at the first control point Mp1 matches the target value at time t1, but the FDT measurement value drops after time t1. Even if FB-FDTC is started at time t1, its effect does not begin to appear until time t3, and it takes time until time t4 for the dropped FDT measurement value to recover to within the acceptable range. This is because the FB-FDTC cannot keep up with changes in the FDT measurement values, resulting in a long delay before the cooling water flow rate and roll speed are changed. Also, as shown by the dashed line L1 in Figure 4, timeThe FDH measurement value at the first control point Mp1 at time t1 matches the target value. By memorizing (locking on) the gauge meter plate thickness in the section where the deviation between the FDH measurement value and the FDH target value at time t1 is small and executing GM-AGC, and in combination with using a hydraulic reduction device with good response as the operating end, fluctuations in plate thickness in sections with rapid temperature changes can be suppressed. Furthermore, by using monitor AGC in conjunction, the FDH measurement value can be kept close to the FDH target value over the entire length of the rolled material.

[0011] Next, in the second learning method, the tail end side of the rapid temperature change section of the rolled material is designated as the control point (hereinafter referred to as the "second control point") Mp2. When the second control point Mp2 is located directly below the exit thermometer 9 and the exit thickness gauge 8, FDT and FDH measurements are collected, and the collected FDT and FDH measurements are used for learning. That is, the setting calculation unit 110 calculates various setting values ​​so that the FDT and FDH measurements at the second control point Mp2 match the target values. As a result, as shown by the dashed line L2 in Figure 3, at time t2, the FDT measurement at the second control point Mp2 matches the FDT target value, and the FDT measurement is controlled to be close to the target value for the portion after the second control point Mp2 as well. On the other hand, the deviation between the FDT measurement and the FDT target value near the first control point Mp1 is relatively large, but the length of the temperature defect outside the acceptable range is shorter than in the first learning method described above. Furthermore, as mentioned above, because the FDT deviation at the first control point Mp1 is large, the deformation resistance, rolling load, and mill elongation models are calculated based on the rolling material temperature at each stand, assuming that the measured FDT value matches the target FDT value. However, in actual rolling, an FDT deviation occurs (in this example, the measured FDT value is higher than the target FDT value). Therefore, the actual rolling material temperature at each stand differs from the prediction (it is higher than the prediction), and the deformation resistance, rolling load, and mill elongation also differ from the prediction (they are smaller than the prediction). As a result, as shown by the dashed line L2 in Figure 4, the FDH deviation at the first control point Mp1 becomes large (the measured FDH value is higher than the target FDH value). smallFurthermore, GM-AGC memorizes (locks on to) the gauge meter thickness in the area with a large FDH deviation near the first control point Mp1 and attempts to maintain that thickness, resulting in a prolonged period of excess thickness. When the leading edge of the rolled material reaches the exit thickness gauge 8 and monitor AGC is started, the thickness deviation gradually decreases from time t3, but the excess thickness continues for a relatively long time.

[0012] Thus, the first learning method resulted in a longer section of the output temperature defect, while the second learning method resulted in a longer section of the output plate thickness defect.

[0013] This disclosure was made to solve the problems described above. The purpose of this disclosure is to provide a rolling control device that can shorten the portion with a poor temperature at the exit end as much as possible without increasing the length of the portion with a poor thickness at the exit end, even when there is a portion with a sudden temperature change at the leading end of the rolled material. [Means for solving the problem]

[0014] The first aspect relates to the rolling control device that controls the temperature and thickness of the rolled material at the exit of the finishing mill. The finishing mill comprises a plurality of stands with rolls, a plurality of cooling devices arranged between the stands, and a rolling load measuring instrument that measures the rolling load of each stand. An exit thickness gauge for measuring the thickness of the rolled material and an exit thermometer for measuring the temperature of the rolled material are arranged at the exit of the finishing mill. The rolling control device comprises a setting calculation unit, a first performance collection unit, a second performance collection unit, a first learning unit, and a second learning unit. Before rolling the rolled material, the setting calculation unit calculates the roll gap setting value and roll peripheral speed setting value for each stand, as well as the cooling water volume setting value for each cooling device, using the exit thickness target value, the exit temperature target value, and a prediction model. The portion where the temperature measured by the exit thermometer at the leading edge of the rolled material transitions from a high-temperature or low-temperature portion to a steady-state portion is defined as a temperature abruptation portion, and the high-temperature or low-temperature portion is defined as the first control point. The first performance data collection unit collects the first exit plate thickness measurement value measured by the exit plate thickness gauge at the first control point during rolling, and the rolling load measurement values ​​of each stand measured by the rolling load measuring instrument. The second performance data collection unit collects the first exit plate thickness measurement value measured by the exit plate thickness gauge at the first control point during rolling of the rolled material. Area where temperature changes rapidly Further towards the tail end and within the steady state At the second control point, the second exit temperature measurement value, measured by the exit thermometer, is collected. After rolling the rolled material, the first learning unit learns the deformation resistance model, rolling load model, and mill elongation model included in the prediction model based on the first exit plate thickness measurement value and rolling load measurement value collected by the first performance collection unit. After rolling the rolled material, the second learning unit learns the temperature model included in the prediction model based on the second exit temperature measurement value collected by the second performance collection unit. The setting calculation unit is configured to calculate the roll gap setting value, roll peripheral speed setting value, and cooling water volume setting value before rolling the next material, using the deformation resistance model, rolling load model, and mill elongation model learned by the first learning unit and the temperature model learned by the second learning unit.

[0015] The second perspective, in addition to the first perspective, has the following further features: The first performance collection unit further collects the first exit temperature measurement value measured by the exit thermometer at the first control point. The rolling control device further includes an exit temperature prediction unit that predicts the finishing mill exit temperature at the first control point based on the exit temperature target value, and a third learning unit that learns the exit temperature prediction value predicted by the exit temperature prediction unit based on the difference between the first exit temperature measurement value and the second exit temperature measurement value after the rolling of the rolled material. The setting calculation unit is configured to predict the rolling load and mill elongation of each stand and calculate the roll gap setting value using the exit temperature prediction value at the first control point learned by the third learning unit and the deformation resistance model, rolling load model, and mill elongation model learned by the first learning unit before rolling the next material.

[0016] Incidentally, there are cases where multiple heating furnaces for heating the rolled material are arranged in parallel upstream of the finishing mill. The section where the temperature changes abruptly near the leading edge of the rolled material occurs depending on the operation of the heating furnaces, as mentioned above. Therefore, the third aspect has the following additional features in addition to the second aspect. At least one of the first learning unit, the second learning unit, and the third learning unit has a layered learning value table divided for each heating furnace, and during learning, it updates the learning value of the section corresponding to the heating furnace from which the rolled material to be learned was extracted, and the setting calculation unit is configured to calculate each setting value using the learning value of the heating furnace section from which the rolled material to be set is extracted. [Effects of the Invention]

[0017] According to the first aspect, by learning the temperature model used for calculating the cooling water amount setting value in the setting calculation unit based on the second outlet temperature measurement value measured at the second management point, the deviation between the second outlet temperature measurement value and the outlet temperature target value at the second management point of the next material can be made as small as possible. As a result, although an outlet temperature deviation occurs at the first management point of the next material, compared with the case of learning using the first outlet temperature measurement value measured at the first management point, the length of the temperature defective part at the tip of the rolled material can be significantly shortened. Further, by learning the deformation resistance model, rolling load model, and mill elongation model used for calculating the roll gap setting value in the setting calculation unit based on the first outlet plate thickness measurement value measured at the first management point, the deviation between the first outlet plate thickness measurement value and the outlet plate thickness target value at the first management point of the next material can be made as small as possible. Therefore, even when there is a temperature abrupt change part at the tip of the rolled material, it is possible to make the outlet temperature defective part as short as possible without increasing the length of the outlet plate thickness defective part. In addition, by further using the existing gauge meter AGC and monitor AGC in combination, the outlet plate thickness measurement value can be made to coincide with the outlet plate thickness target value over the entire longitudinal direction of the next material.

[0018] According to the second aspect, based on the difference between the first outlet temperature measurement value and the second outlet temperature measurement value, the outlet temperature predicted value Learn By doing so, in combination with learning the deformation resistance model, rolling load model, and mill elongation model, the roll gap setting value can be calculated with higher accuracy. As a result, the outlet plate thickness measurement value can be made to coincide more closely with the outlet plate thickness target value.

[0019] According to the third aspect, when a plurality of heating furnaces are arranged in parallel, each learning unit can learn with an optimal learning value according to the operation of each heating furnace.

Brief Description of the Drawings

[0020] [[ID=1】 [Figure 1] It is a schematic diagram schematically showing the configuration of a hot rolling line to which the rolling control device according to the embodiment is applied. [Figure 2]It is a schematic diagram schematically showing the configuration of a process control computer which is a rolling control device according to an embodiment. [Figure 3] It is a diagram for explaining the change in the temperature on the outlet side of the finishing mill. [Figure 4] It is a diagram for explaining the change in the plate thickness on the outlet side of the finishing mill. [Figure 5] It is a diagram showing an example of the hardware configuration of a process control computer that implements a rolling control device. [Figure 6] It is a diagram showing a learning value table. [Figure 7] It is a schematic diagram showing the configuration of a conventional rolling control device. [Figure 8] It is a diagram for explaining a temperature abrupt change portion generated at the tip portion of a rolled material.

Embodiments for Carrying Out the Invention

[0021] Hereinafter, with reference to the drawings, embodiments of the present disclosure will be described by taking the case of applying to a hot rolling line RL as an example. In addition, the same reference numerals are given to common elements in each figure, and redundant explanations are omitted.

[0022] FIG. 1 is a schematic diagram schematically showing the configuration of a hot rolling line RL to which a rolling control device according to an embodiment is applied. The hot rolling line RL includes, as main equipment, at least one heating furnace 1, a rough mill 2, a descaling device 3, a finishing mill 4, a water cooling table 5, and a coiler 6.

[0023] The heating furnace 1 heats the rolled material (slab) M. The rolled material M is a metal material such as steel with a thickness of approximately 170 mm to 280 mm. The heating furnace 1 heats the inside of the furnace to a high temperature by burning heavy oil or gas, and the rolled material M is heated to approximately 1200°C by passing it through the furnace over a period of time, for example, 3 to 4 hours. The first half of the furnace is at a high temperature and is called the heating zone, where the rolling material M is heated. The second half of the furnace is at a lower temperature than the heating zone and is called the uniform zone, where the temperature of the rolled material M is made uniform through heat conduction within the rolled material M. As mentioned above, if the rolled material M is heated rapidly in the heating zone and the time spent in the uniform zone is short, a sudden temperature change will occur at the leading edge of the rolled material M when it is removed from the heating furnace 1.

[0024] The rough mill 2 is equipped with one or two stands R1 and R2. The rough mill 2 repeatedly rolls the rolled material M while reversing the direction of travel, processing it into a rolled material (intermediate bar) M with a thickness of approximately 20 mm to 45 mm. The descaling device 3 removes oxide scale from the surface of the rolled material M by spraying high-pressure water (descaling water). The descaling device 3 has multiple headers for spraying high-pressure water, and each header can be turned ON / OFF. By controlling the number of headers that are turned ON and changing the flow rate of high-pressure water, the outlet temperature FDT is changed.

[0025] The finishing mill 4 is equipped with multiple (seven in the example shown in Figure 1) stands Fi (i=1 to 7). Each stand Fi has a pair of upper and lower work rolls (rolling rolls) 41, a pair of upper and lower backup rolls 42, and a motor 43 for rotating the work rolls 41. The backup rolls 42 are equipped with a hydraulically controlled reduction device (hydraulic cylinder) 44, which allows the roll gap to be changed. Each stand Fi also has a rolling load measuring instrument 45 for measuring the rolling load of each stand Fi. The rolling load measuring instrument 45 can be composed of a load cell, but it can also be configured to calculate the rolling load from the hydraulic pressure of the hydraulic reduction device 44.

[0026] Multiple cooling devices ISCi (i=1~6) are positioned between the stands Fi of the finishing mill 4. Each cooling device ISCi, also called an inter-stand spray, is designed so that the cooling water flow rate can be changed by a proportional valve or the like. Changing the cooling water flow rate of any of the cooling devices ISCi changes the outlet temperature FDT. Although not shown in the diagram, induction heating devices (IH) can be installed on the inlet side of the finishing mill 4 or between the stands Fi. In this case, the outlet temperature FDT can be changed by controlling the power supply to change the heating capacity.

[0027] The water-cooled table 5 cools the rolled material M that has passed through the finishing mill 4 with cooling water. The coiler 6 winds the rolled material M into a coil product.

[0028] An entry-side thermometer 7 is positioned at the entry side of the finishing mill 4, allowing for the measurement of the temperature (hereinafter also referred to as "entry-side temperature") FET of the rolled material M at the entry side of the finishing mill 4. An exit-side plate thickness gauge 8 and an exit-side thermometer 9 are positioned at the exit-side plate thickness FDH and exit-side temperature FDT, allowing for the measurement of the exit-side plate thickness FDH and exit-side temperature FDT.

[0029] The hot rolling line RL is operated by a computer-based control system. The computer system includes a host computer 10 and a process control computer 11, which are connected to each other via a network. An interface screen 12, which is the operator's control screen, is connected to the process control computer 11 via the network. The operator can perform operations such as inputting control conditions on the interface screen 12.

[0030] The higher-level computer 10 determines the steel grade of the rolled material M, the target thickness value at the entry side of the finishing mill, the target thickness value at the exit side of the finishing mill (product thickness), and the target temperature value at the exit side of the finishing mill, according to the operation plan, and transmits the determined items as initial information to the process control computer 11. The initial information also includes the heating conditions of the heating furnace 1.

[0031] In a hot rolling line RL, the exit thickness FDH and exit temperature FDT of the rolled material M are important product indicators, and it is desirable to minimize the defective portion where deviations from these target values ​​fall outside the acceptable range.

[0032] The process control computer 11 calculates the setting values ​​for each piece of equipment that can achieve the FDH target value and FDT target value based on the initial information from the computer 10 and the control conditions provided from the interface screen 12, and sets the calculated setting values ​​for each piece of equipment. While each piece of equipment is in operation, the process control computer 11 modifies (changes) each setting value according to the values ​​obtained from various measuring instruments. The process control computer 11, which is a rolling control device, will be described in detail below.

[0033] Figure 2 is a schematic diagram showing the configuration of the process control computer 11, which is a rolling control device according to the embodiment. Figure 3 is a diagram illustrating the change in the finishing mill exit temperature FDT. Figure 4 is a diagram illustrating the change in the finishing mill exit plate thickness FDH. As shown in Figures 3 and 4, the leading edge portion of the rolled material M of The section where the FDT measurement value transitions from a high-temperature section (where the value is higher than the steady-state section) to a steady-state section is defined as the temperature abruption section. The high-temperature section of the rolled material M is designated as the first control point, and the second control point is located towards the tail end from the temperature abruption section.

[0034] The process control computer 11 includes a setting calculation unit 110, a first performance data collection unit 111, a second performance data collection unit 112, a first learning unit 113, a second learning unit 114, a third learning unit 115, an exit temperature prediction unit 116, an AGC 117, and an FDTC 118. Note that the feedback plate thickness control unit (AGC) and the feedback temperature control unit (FDTC) have already been described, so a detailed explanation is omitted here.

[0035] Based on initial information input from the higher-level computer 10 (for example, the steel grade of the rolled material M, the target FET value, the target FDH value, and the target FDT value), the setting calculation unit (FSU) 110 calculates and sets for each piece of equipment, using a prediction model, at least one of the following settings: the roll peripheral speed of each stand Fi, the cooling water flow rate of the inter-stand cooling device ISCi, the descaling water flow rate of the descaling device 3, and the heating power of the induction heating device, as well as the roll gap setting value of each stand Fi, before the rolled material M enters the finishing mill 4. The calculation of these setting values ​​takes into account water cooling heat transfer by the inter-stand cooling water in the finishing mill 4, thermal radiation, cooling by air convection, processing heat generated due to the deformation of the rolled material M at each stand Fi, frictional heat generation and contact heat dissipation between the work roll 41 and the rolled material M. A temperature model, which is a set of mathematical formulas that represent the influence of these factors, is used. The temperature model is publicly known, as disclosed in, for example, Patent Document 2. The setting calculation unit 110 first sets the predetermined roll peripheral speed and cooling water flow rate settings for the final stand F7 as initial values. If there is sufficient margin in the cooling water flow rate range, it adjusts the cooling water flow rate setting so that the exit temperature FDT at the leading edge of the rolled material M reaches the FDT target value. If the cooling water flow rate setting reaches the limit and changing the cooling water flow rate alone is insufficient, the setting calculation unit 110 changes the roll peripheral speed of the final stand F7 so that the exit plate thickness FDT reaches the FDT target value. At this time, it calculates the roll peripheral speed setting value for each stand Fi so that the volume velocity of the rolled material M between each stand Fi is equal. In this way, the roll peripheral speed setting value for the final stand F7 and the cooling water flow rate setting value between each stand Fi are determined, and then, based on these settings, each piece of equipment in the finishing mill 4 is set up until the leading edge of the rolled material M reaches the finishing mill 4.

[0036] The first performance data collection unit 111 collects (samples) the first FDT measurement value measured by the exit thermometer 9 at the first control point Mp1 during rolling, and the rolling load measurement value measured by the rolling load measuring instrument 45 at each stand Fi. The position of the first control point Mp1 is predetermined so that it is before the sudden temperature change section (e.g., the high-temperature section) for rolled material M which has a sudden temperature change section near the tip. At each stand Fi, the position of the sudden temperature change section is tracked considering the stretching due to the change in plate thickness during rolling. When determining the first control point Mp1, it should be noted that if the first control point Mp1 is too close to the tip, the measurement of the first FDT measurement value by the exit thermometer 9 may become unstable. Furthermore, sampling is performed based on the position of the rolled material M detected by sensors and transport time information on the hot rolling line RL, which are not shown in the illustration. The method for detecting the position of the rolled material M is well known, so a detailed explanation is omitted here.

[0037] The second performance data collection unit 112 collects the first FDT measurement value measured by the exit thermometer 9 at the first control point Mp1 during rolling, and also collects the second FDT measurement value measured by the exit thermometer 9 at the second control point Mp2. The position of the second control point Mp2 is determined to be on the tail end side of the range of variation in the position of the sudden temperature change section, taking into consideration the variation in that section.

[0038] The first learning unit 113 learns the rolling load model based on the rolling load measurements of each stand Fi at the first control point Mp1 collected by the first performance collection unit 111. There are various methods for this learning, but for example, as shown in equation (1) below, a method is used in which the ratio obtained by dividing the rolling load measurement value by the rolling load prediction value (prediction value before correction by learning) is calculated, and this is allocated with the first learning value Z1b before the update by a predetermined allocation rate (β1) to obtain a new (updated) first learning value Z1a. The first learning value Z1 is, for example, a parameter of the set of mathematical formulas that describe the rolling load model. Z1a = Z1b × (1 - β1) + (Measured rolling load / Predicted rolling load) × β1 ... (1)

[0039] The second learning unit 114 learns the temperature model based on the second FDT measurement value of the second control point Mp2 collected by the second performance collection unit 112. There are various learning methods, but for example, as shown in equation (2) below, a method is used in which the difference between the second FDT measurement value and the actual inlet temperature value at the second control point Mp2 is divided by the difference between the predicted FDT value (predicted value before correction by learning) and the actual inlet temperature value to obtain a ratio, and this ratio is allocated with the second learning value Z2b before updating by a predetermined allocation rate (β2) to obtain a new (updated) second learning value Z2a. Z2a = Z2b × (1 - β2) + {(FET actual value - 2nd FDT measured value) / (FET actual value - FDT predicted value)} × β2 ···(2)

[0040] Here, the FET measured by the inlet thermometer 7 can be used as the starting point for the temperature model calculation, but is not limited to this. The FET measured value and the FET estimated value can be allocated and used as the FET actual value. The FET estimated value can be estimated based on the state of the rolled material M at the outlet of the rough mill 2 and the transport conditions from the rough mill 2 to the finish mill 4 (transport time, state of the heat-insulating cover, etc.).

[0041] The third learning unit 115 calculates the difference between the first FDT measurement value (FDT1) at the first control point Mp1 and the second FDT measurement value (FDT2) at the second control point Mp2, for example, as shown in equation (3) below, and apportions the calculated difference with the third learning value Z3b before the update using a predetermined apportionment rate (β3) to obtain a new (updated) third learning value Z3a. Z3b=Z3b×(1-β3)+(FDT1-FDT2)×β3...(3)

[0042] Before rolling the next rolled material (next material) M, the third learning unit 115 corrects the FDT prediction value predicted by the exit temperature prediction unit 116, which will be described later, using the temperature model learned by the second learning unit 114, for example, as shown in equation (4) below. If the actual FET value has already been obtained at the time of the setting calculation, the actual FET value can be used instead of the predicted FET value. FDT predicted value (after learning) = FET predicted value - (FET predicted value - FDT predicted value (before learning) × 2nd learning value ... (4)

[0043] The setting calculation unit 110 calculates at least one of the following set values: roll peripheral speed, ISC cooling water flow rate, descaling water flow rate of the descaling device, and heating power of the induction heating device, so that the FDT predicted value (after learning reflection) matches the FDT target value. The roll peripheral speed of each stand Fi (i=1~6) other than the final stand F7 can be calculated, for example, from the roll peripheral speed of the final stand F7 using the law of constant advance rate and volume velocity, as shown in equation (5) below. Fi roll peripheral speed = {(1 + F7 advance rate) × F7 roll peripheral speed × F7 exit plate thickness} / {(1 + Fi advance rate) × Fi exit plate thickness} ... (5)

[0044] The advance rate is the deviation ratio between the roll peripheral speed of stand Fi and the rolling speed at the exit side of stand Fi. The advance rate can be calculated using a theoretically or experimentally derived advance rate model, based on the entry and exit plate thicknesses of stand Fi.

[0045] The outlet temperature prediction unit 116 predicts the outlet temperature of the finishing mill 4 at the first control point Mp1 based on the outlet temperature target value. The outlet temperature prediction unit 116 calculates the FDT prediction value using the learning results of the third learning unit 115 as shown in equation (6) below. FDT predicted value = FDT predicted value (after learning) + 3rd learning value ... (6)

[0046] The setting calculation unit 110 also calculates the temperature of each stand Fi at the first control point Mp1 using the FDT predicted value, and uses the learning results of the first learning unit 113 to calculate the rolling load predicted value (after learning reflection) for each stand Fi as shown in equation (7) below. Predicted rolling load (after learning) = Predicted rolling load (before learning) × 1st learning value ... (7)

[0047] The setting calculation unit 110 uses the predicted rolling load value (after learning) for each stand Fi to predict the mill elongation of each stand Fi and calculates the roll gap setting value for each stand Fi.

[0048] By performing the next material setting calculation in this manner, the FDT deviation can be reduced over the entire length of the rolled material M, including the area near the leading edge. Although FDT deviation may still occur in the section before the sudden temperature change, the length of the temperature-defective section where the FDT measurement value falls outside the acceptable range is significantly shorter compared to the conventional first learning method. Moreover, the FDH measurement value at the first control point Mp1 can be accurately matched to the FDH target value. By reflecting the learning results in the temperature calculation of the first control point Mp1 of each stand (represented by the position tracked considering the stretching associated with rolling), not only the temperature of the first control point Mp1 of each stand, but also the deformation resistance, rolling load, and roll gap calculated using it can be predicted and calculated with good accuracy, so the FDH measurement value at the first control point Mp1 can be accurately matched to the FDH target value. Furthermore, during rolling, by using a gauge meter AGC that estimates the change in the elastic deformation of the rolling rolls based on the rolling load measurement and controls the plate thickness by manipulating the roll gap, plate thickness fluctuations in areas with rapid temperature changes can be suppressed, and the exit plate thickness FDH can be kept constant. Since this gauge meter AGC operates the roll gap using a hydraulic reduction device 44 with a fast response speed, it can quickly follow even if there is a sudden change in the rolling load measurement, and can suppress fluctuations in the exit plate thickness FDH. In addition, a monitor AGC is used in combination to operate the roll gap of each stand Fi to reduce the FDH deviation based on the FDH measurement value. However, there is a distance of several meters between the final stand F7 of the finishing mill 4, which is the target of the finishing operation, and the exit plate thickness gauge 8, and the monitor AGC cannot be applied to the portion corresponding to this distance. Despite these limitations, the FDH deviation can be further reduced by using the monitor AGC in combination.

[0049] There are no limitations on the specific structure of the process control computer 11, but as an example, it may be as follows. Figure 5 shows an example of the hardware configuration of the process control computer 11. The functions of the process control computer 11 can be realized by the processing circuit shown in Figure 5. This processing circuit may be dedicated hardware 11a. This processing circuit may also include a processor 11b and memory 11c. This processing circuit may be partially formed as dedicated hardware 11a and further include a processor 11b and memory 11c. In the example in Figure 5, part of the processing circuit is formed as dedicated hardware 11a, and the processing circuit also includes a processor 11b and memory 11c.

[0050] At least a portion of the processing circuit may be at least one dedicated hardware 11a. In this case, the processing circuit may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof.

[0051] The processing circuit may include at least one processor 11b and at least one memory 11c. In this case, each function of the process control computer 11 is realized by software, firmware, or a combination of software and firmware. The software and firmware are written as programs and stored in the memory 11c. The processor 11b realizes the functions of each part of the rolling control device 11 by reading and executing the programs stored in the memory 11c.

[0052] The processor 11b is also called a CPU (Central Processing Unit), central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, or DSP. Memory 11c includes non-volatile or volatile semiconductor memory such as RAM, ROM, flash memory, EPROM, and EEPROM.

[0053] In this way, the processing circuit can realize each function of the rolling control device 11 through hardware, software, firmware, or a combination thereof.

[0054] As explained above, according to this disclosure, by learning the temperature model used in the calculation of the cooling water volume set value in the setting calculation unit 110 based on the second FDT measurement value measured at the second control point Mp2, the deviation between the second FDT measurement value at the second control point Mp2 of the next material and the FDT target value can be made as small as possible. As a result, although an FDT deviation occurs at the first control point Mp1 of the next material, the length of the temperature defect portion at the leading edge of the rolled material can be significantly shortened compared to when learning using the first FDT measurement value measured at the first control point Mp1. Furthermore, by learning the deformation resistance model, rolling load model, and mill elongation model used in the calculation of the roll gap set value in the setting calculation unit 110 based on the first FDH measurement value measured at the first control point Mp1, the deviation between the first FDH measurement value at the first control point Mp1 of the next material and the FDH target value can be made as small as possible. In this way, by changing the first control point Mp1, which collects FDH measurements, and the second control point Mp2, which collects FDT measurements, it is possible to minimize the temperature-defective portion without lengthening the thickness-defective portion (i.e., without reducing the controllability of FDH), even when there is a sudden temperature change at the leading edge of the rolled material. Furthermore, by using FB-FDTC in combination, the FDT measurement value can be matched to the FDT target value along the entire longitudinal direction. In addition, by further using existing gauge meters AGC and monitor AGC in combination, the FDH measurement value can be matched to the FDH target value along the entire longitudinal direction of the next material.

[0055] While embodiments of this disclosure have been described above, this disclosure is not limited to the embodiments described above and can be implemented in various modified forms without departing from the spirit of this disclosure. When the number of elements, quantities, amounts, ranges, etc., are mentioned in the embodiments described above, this invention is not limited to the number mentioned unless it is specifically stated or clearly defined in principle. Furthermore, the structures, etc., described in the embodiments described above are not necessarily essential to this invention unless they are specifically stated or clearly defined in principle.

[0056] In the above embodiment, the case where the hot rolling line RL is equipped with one heating furnace 1 was described as an example, but there are cases where multiple heating furnaces (not shown) are arranged side by side. The sudden temperature change portion at the leading edge of the rolled material M occurs depending on the operation of the heating furnace 1, as described above. In this case, at least one of the first learning unit 113, the second learning unit 114, and the third learning unit 115 can be configured to have a layered learning value table divided for each heating furnace (divided into three divisions 1A, 1B, and 1C in the figure), as shown in Figure 6. Figure 6 is a diagram showing the learning value table. During learning, the learning values ​​Z1 to Z3 of the division corresponding to the heating furnace from which the rolled material M to be learned is extracted are updated, and the setting calculation unit 110 can be configured to calculate each setting value using the learning values ​​Z1_1 to Z3_3 of divisions 1A, 1B, and 1C of the heating furnace 1 from which the rolled material M to be set is extracted. According to this, each learning unit 113 to 115 can learn with an optimal learning value corresponding to the operation of each heating furnace 1. [Explanation of Symbols]

[0057] 1…Heating furnace, 2…Coarse mill, 3…Descaling device, 4…Finishing mill, Fi…Stand, 41…Work roll, 42…Backup roll, 43…Motor, 44…Reduction device, 45…Rolling load measuring instrument, Fi…Stand, ISCi…Cooling device, 5…Water-cooled table, 6…Coiler, 7…Inlet thermometer, 8…Outlet plate thickness gauge, 9…Outlet thermometer, 11…Rolling control device, process control computer, 110…Setting calculation unit, 111…First performance collection unit, 112…Second performance collection unit, 113…First learning unit, 114…Second learning unit, 115…Third learning unit, 116…Outlet temperature prediction unit, 117…Feedback plate thickness control unit (AGC), 118…Feedback temperature control unit (FDTC), M…Rolled material

Claims

1. A rolling control device that controls the temperature and thickness of the rolled material at the exit of the finishing mill, The finishing mill comprises a plurality of stands having rolls, a plurality of cooling devices arranged between the stands, and a rolling load measuring instrument for measuring the rolling load of each stand, and an exit thickness gauge for measuring the thickness of the rolled material and an exit thermometer for measuring the temperature of the rolled material are arranged at the exit side of the finishing mill, Before rolling the rolled material, a setting calculation unit calculates the roll gap setting value and roll peripheral speed setting value for each stand, as well as the cooling water volume setting value for each cooling device, using the exit plate thickness target value, exit temperature target value, and prediction model. The portion of the rolling material at the leading edge where the temperature measured by the exit thermometer is higher or lower than the steady state is defined as a temperature abruption section, the high-temperature section or the low-temperature section is defined as a first control point, and during rolling, a first performance collection unit collects the first exit thickness measurement value measured by the exit thickness gauge and the rolling load measurement values ​​of each stand measured by the rolling load measuring instrument at the first control point. During the rolling of the rolled material, a second performance collection unit collects a second exit temperature measurement value measured by the exit thermometer at a second control point within the steady-state section, located on the tail end side of the rapid temperature change section. After the rolling of the rolled material, a first learning unit learns the deformation resistance model, rolling load model, and mill elongation model included in the prediction model based on the first exit plate thickness measurement value and the rolling load measurement value collected by the first performance collection unit. The rolling equipment includes a second learning unit that, after the rolling of the rolled material, learns the temperature model included in the prediction model based on the second exit temperature measurement value collected by the second performance collection unit, The setting calculation unit is configured to calculate the roll gap setting value, the roll peripheral speed setting value, and the cooling water volume setting value before rolling the next material, using the deformation resistance model, the rolling load model, and the mill elongation model learned by the first learning unit, and the temperature model learned by the second learning unit.

2. A rolling control device according to claim 1, wherein the first performance collection unit further collects the first outlet temperature measurement value measured by the outlet thermometer at the first control point, An outlet temperature prediction unit predicts the outlet temperature of the finishing mill at the first control point based on the aforementioned outlet temperature target value, The system further includes a third learning unit that learns the predicted exit temperature value predicted by the exit temperature prediction unit based on the difference between the first exit temperature measurement value and the second exit temperature measurement value after the rolling of the rolled material, The setting calculation unit is configured to predict the rolling load and mill elongation of each stand and calculate the roll gap setting value before rolling the next material, using the predicted exit temperature value of the first control point learned by the third learning unit, and the deformation resistance model, rolling load model, and mill elongation model learned by the first learning unit.

3. A rolling control device according to claim 2, In a system where multiple heating furnaces for heating rolled material are arranged in parallel upstream of the finishing mill, At least one of the first learning unit, the second learning unit, and the third learning unit has a layered learning value table divided for each heating furnace, and during learning, it updates the learning value of the section corresponding to the heating furnace from which the rolled material to be learned was extracted. The setting calculation unit is a rolling control device configured to calculate each setting value using learned values ​​of the heating furnace classifications from which the rolled material to be set is extracted.

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