JP6399985B2 - Winding temperature control device and winding temperature control method - Google Patents

Description

  The present invention relates to a winding temperature control device and a winding temperature control method for controlling a winding temperature of a steel sheet in a hot rolling line for the steel sheet.

  A technique of controlling the winding temperature by changing the target winding temperature in the longitudinal direction of the steel sheet in a hot rolling line for steel sheets has been often used for various purposes. For example, in Patent Document 1, in the process of winding a rolled steel sheet around a coil, when the length from the tail end of the steel sheet becomes ΔL, the tail end temperature is increased by a predetermined amount Δt from the target winding temperature. An example of winding temperature control is disclosed in which a taper-shaped or step-shaped temperature control command is output so as to increase the winding temperature to increase the winding temperature. According to the winding temperature control, after cooling, the coil outer circumference side has a larger amount of contraction than the inner circumference side, so the coil is wound from the outer circumference side and coil deformation due to loose winding is suppressed. can do.

  Patent Document 2 defines a target coiling temperature profile in the longitudinal direction of the steel sheet called a U pattern, and in accordance with the target coiling temperature profile, the coil has a higher coil than the central part at the tip and tail ends. An example of the winding temperature control for realizing the temperature is disclosed. In the winding temperature control using the target winding temperature profile of the U pattern, the winding temperature of the coil tip is higher than that in the center, so that the winding property to the downcoiler is improved, and the coil tail end Since the coiling temperature is higher than that at the center, it is possible to cancel out the high cooling effect on the outer periphery of the coil.

JP 2009-214112 A Japanese Patent Laying-Open No. 2015-66587

  The winding temperature control method disclosed in Patent Document 1 and Patent Document 2 sets the winding temperature in a limited range at the tip and tail ends of the coil to be higher than that at the center, thereby improving rolling operability. And the quality of the tip and tail ends of the coil (steel plate). These coiling temperature control methods simply change the coiling temperature by paying attention to the steel sheet part such as the rolling length and the remaining length of the steel sheet, and the speed change of the steel sheet during rolling affects the steel sheet quality. The influence was not considered at all. For this reason, there has been no control for changing the winding temperature in response to the change in speed of the steel sheet during cooling and winding after rolling.

  In view of the above-mentioned problems of the prior art, the object of the present invention is to reduce the influence of steel sheet speed changes during rolling, particularly cooling and winding, on the material properties (strength, hardness, ductility, etc.) of the steel sheet. An object of the present invention is to provide a winding temperature control device and a winding temperature control method capable of improving the uniformity of material properties in the longitudinal direction.

The present invention comprises a plurality of cooling headers that open and close the nozzles according to a cooling header open / close command, and discharges water from the cooling header at a position before the steel plate discharged from the hot rolling finishing mill is wound by the downcoiler. A coiling temperature control device for a cooling device for cooling the steel plate, wherein the steel plate passes through the cooling device at a preset steel plate speed before the steel plate is cooled. A first cooling command calculation unit that calculates the cooling header opening / closing command so that the predicted winding temperature substantially matches a preset target winding temperature, and the steel plate is cooled by the cooling device. when it is, to detect the steel sheet speed of said steel sheet, the coiling temperature correction amount calculation for calculating a correction amount of the coiling temperature for keeping the material of the steel sheet constant in response to a change of the steel sheet speed When the first cooling header switching command calculated by the cooling command calculator, and have use of the control amount obtained based on the correction amount of the winding temperature calculated by the winding temperature correction amount calculating section And a second cooling command calculation unit that corrects and outputs the corrected cooling header opening / closing command to the cooling device.

  According to the present invention, the influence of the speed change of the steel sheet during rolling, especially cooling and winding, on the material properties (strength, hardness, ductility, etc.) of the steel plate is reduced, and the uniformity of the material properties in the longitudinal direction of the steel plate is reduced. Will improve.

The figure which showed the example of the structure of a winding temperature control apparatus and its control object. The figure which showed the example of the structure of the target winding temperature table memorize | stored in a target winding temperature memory | storage part. The figure which showed the example of the structure of the speed pattern table memorize | stored in a speed pattern memory | storage part. The figure which showed the example of the structure of the cooling header priority table memorize | stored in a cooling header priority memory | storage part. The figure which showed the example of the opening / closing pattern of the cooling header allocated to the control code used with a winding temperature control apparatus. The figure which showed the example of the processing flow of the preset cooling command calculation process which a preset cooling command calculation part performs. The figure which showed the example of the detailed process flow of the coiling temperature prediction calculation process (step S15) in the preset cooling command calculation process of FIG. The figure which showed the example of the process in which a control code is optimized in the preset cooling command calculation process of FIG. The figure which showed the example of the processing flow of the influence coefficient calculation process which an influence coefficient calculation part performs. The figure which showed the example of the processing flow of the material prediction process which a material prediction part performs. The figure which showed the example of the processing flow of the winding temperature correction amount calculation process which a winding temperature correction amount calculation part performs. The figure which showed the example of the processing flow of the winding temperature command calculation process which a winding temperature command calculation part performs. The figure which showed the example of the processing flow of the cooling header command calculation process which a cooling header command calculation part performs.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing an example of the configuration of the winding temperature control device 100 and its controlled object 50. The winding temperature control device 100 receives various signals from the controlled object 50 and outputs various control signals to the controlled object 50. Hereinafter, the configuration of the controlled object 50 will be described first with reference to FIG.

  In the case of this embodiment, the controlled object 50 is a winding temperature control line in hot rolling. In the winding temperature control line, the steel plate 51 delivered from the finishing mill 52 is cooled by the winding cooling device 57 at a position immediately before being wound on the downcoiler 55. That is, the steel plate 51 of, for example, 850 ° C. to 900 ° C. rolled by the finishing mill 52 including the plurality of rolling stands 53 provided with the work rolls 54 is cooled by the winding cooling device 57 and taken up by the downcoiler 55. In FIG. 1, the steel plate 51 is moved in the direction of the arrow drawn on the side (from the right side to the left side) and is taken up by the downcoiler 55.

  The winding cooling device 57 includes an upper cooling device 58 that cools the steel plate 51 from above and a lower cooling device 59 that cools the steel plate 51 from below. Each of the upper cooling device 58 and the lower cooling device 59 is provided with a plurality of (for example, 120) cooling headers 61 in the longitudinal direction of the steel plate 51. Here, each cooling header 61 is configured by arranging a plurality (for example, 20) of nozzles for discharging water in the width direction of the steel plate 51. In addition, the plurality of cooling headers 61 provided along the longitudinal direction of the steel plate 51 are grouped by a predetermined number (for example, five), and each group of the grouped cooling headers 61 includes the bank 60. be called.

  The winding thermometer 56 measures the temperature of the steel plate 51 immediately after the steel plate 51 passes through the winding cooling device 57 and is taken up by the downcoiler 55, and reports the measured temperature to the winding temperature control device 100. . Although omitted in FIG. 1, a thermometer for measuring the temperature of the steel plate 51 is usually provided on the exit side of the finishing mill 52. The purpose of the coiling temperature control by the coiling temperature control device 100 is to control the temperature measured by the coiling thermometer 56 according to the target coiling temperature, to control the material of the steel plate 51 to a desired value, The purpose is to obtain a uniform material in the longitudinal direction of the steel plate 51. At this time, the target winding temperature may be constant at each part in the longitudinal direction of the steel plate 51, or may be set to a value slightly higher than the central portion at the front end portion and the tail end portion.

  Next, the configuration of the winding temperature control device 100 will be described. As shown in FIG. 1, the winding temperature control device 100 is roughly divided into a preset control unit 10 and a dynamic control unit 30.

  The preset control unit 10 includes a preset cooling command calculation unit 11, an influence coefficient calculation unit 12, a material prediction unit 13, a target winding temperature storage unit 21, a speed pattern storage unit 22, a cooling header priority storage unit 23, and a plate temperature estimation model. It is configured including functional blocks such as the storage unit 24.

  Here, in the target winding temperature storage unit 21, the speed pattern storage unit 22, and the cooling header priority storage unit 23, the target winding temperature of various steel plates 51 rolled by the finishing mill 52, the steel plate 51 during rolling, and the like. Information such as the speed pattern and cooling header priority is stored in advance. The plate temperature estimation model storage unit 24 stores a calculation model for estimating the temperature of the steel plate 51 when the steel plate 51 is rolled and cooled. Note that the information and calculation model stored in these storage units may be supplied from a host computer 40 via a communication network (not shown), but a portable storage medium such as a USB (Universal Serial Bus) memory may be used. It may be supplied via the terminal.

Prior to the cooling of the steel plate 51, the preset cooling command calculation unit 11 sets the target winding temperature storage unit 21, the speed pattern storage unit 22, and the cooling header priority storage according to the steel type, plate thickness, plate width, and the like of the steel plate 51. Necessary information is acquired from the unit 23, and using the plate temperature estimation model stored in the plate temperature estimation model storage unit 24, the nozzle opening / closing command information of the cooling header 61 for realizing the target winding temperature. Calculate the header pattern. Then, a control code corresponding to the header pattern is output to the dynamic control unit 30 side.
Information that instructs opening / closing of the nozzles of the cooling header 61 such as this control code is generally called a cooling header opening / closing command. In the following description, opening and closing of the nozzles of the cooling header 61 is simply referred to as opening and closing of the cooling header 61.

  When the material predicting unit 13 is wound by the downcoiler 55 from the chemical composition of the steel sheet 51 to be cooled, the rolling schedule, the rolling reduction of each rolling stand 53 and the temperature change of the steel sheet 51 calculated using the rolling schedule. The material characteristics of the steel plate 51 are predicted. Further, the influence coefficient calculation unit 12 takes in the calculation result of the material prediction unit 13 and calculates the relationship between the change in rolling speed and winding temperature and the change in material characteristics as an influence coefficient.

  On the other hand, the dynamic control unit 30 includes functional blocks such as a winding temperature correction amount calculation unit 31, a feedforward control unit 32, a winding temperature command calculation unit 33, a feedback control unit 34, and a cooling header command calculation unit 35. Is done. When the steel plate 51 is cooled by the winding cooling device 57 while acquiring information such as a control code (information specifying a header pattern) output from the preset control unit 10 prior to cooling of the steel plate 51. The measurement temperature of the winding thermometer 56, the moving speed (steel plate speed) of the steel plate 51, and the like are acquired. Then, according to the acquired value, the control code acquired from the preset control unit 10 is appropriately corrected, converted into a header pattern, and output to the control target 50.

  Here, the winding temperature correction amount calculation unit 31 obtains the speed change of the steel plate 51 from the control target 50 and uses the influence coefficient calculated by the influence coefficient calculation part 12 to select the material corresponding to the speed change. Calculate the correction amount of the coiling temperature to keep it constant. In addition, the feedforward control unit 32 calculates a control code change amount according to the winding temperature correction amount calculated by the winding temperature correction amount calculation unit 31. Further, the winding temperature command calculation unit 33 determines the winding temperature to be actually used in the control based on the target winding temperature and the correction amount of the winding temperature calculated by the winding temperature correction amount calculation unit 31. Calculate command value (control target coiling temperature). The feedback control unit 34 also changes the header pattern in a direction to reduce the deviation between the coiling temperature command value calculated by the coiling temperature command calculation unit 33 and the coiling temperature measured by the coiling thermometer 56. The control code change amount corresponding to the change amount at the time is calculated. The cooling header command calculation unit 35 is based on the control code output from the preset cooling command calculation unit 11, the control code calculated by the feedforward control unit 32, and the control code calculated by the feedback control unit 34. The header pattern is calculated and output to the winding cooling device 57.

  The winding temperature control device 100 having the configuration and functions as described above is realized by a computer or workstation including an arithmetic processing device and a storage device (not shown). At this time, the preset cooling command calculation unit 11, the influence coefficient calculation unit 12, the material prediction unit 13, the winding temperature correction amount calculation unit 31, the feedforward control unit 32, the winding temperature command calculation unit 33, the feedback control unit 34, the cooling The header command calculation unit 35 is realized by the arithmetic processing unit executing a predetermined program stored in the storage device including a semiconductor memory or a hard disk device. Further, the target winding temperature storage unit 21, the speed pattern storage unit 22, the cooling header priority storage unit 23, and the plate temperature estimation model storage unit 24 are stored in an area where predetermined data is allocated to a part of the storage device. It is realized by doing.

  FIG. 2 is a diagram showing an example of the configuration of the target winding temperature table 21T stored in the target winding temperature storage unit 21. As shown in FIG. As shown in FIG. 2, the target winding temperature table 21 </ b> T is a table in which the target temperature when the coil is wound around the downcoiler 55 is associated with each type (steel type) of the steel plate 51 to be cooled. In the example of the target winding temperature table 21T shown in FIG. 2, for example, a target winding temperature of 630 ° C. is associated with the steel plate 51 whose steel type is SS400. The preset cooling command calculation unit 11 determines the steel type of the steel plate 51, and acquires the target winding temperature corresponding to the steel type from the target winding temperature table 21T.

  In the example of the target winding temperature table 21T in FIG. 2, the target winding temperature is stratified only by the type (steel type) of the steel plate, but is further stratified by the plate thickness and the plate width. May be. Further, the winding temperature control device 100 does not include the target winding temperature storage unit 21, and the target winding temperature is included in a part of the information of the steel plate 51 transmitted from the host computer 40 each time rolling (that is, winding). It may be included.

  FIG. 3 is a diagram showing an example of the configuration of the speed pattern table 22T stored in the speed pattern storage unit 22. As shown in FIG. 3, the speed pattern table 22T relates to the rolling speed of the steel sheet 51 when the steel sheet 51 is paid out from the finishing mill 52 for each combination of the steel type, sheet thickness, and sheet width of the steel sheet 51. It is a table in which speed, first acceleration, second acceleration, steady speed, deceleration, final speed, and the like are associated with each other. Here, the initial speed is the rolling speed of the steel sheet 51 when the front end of the steel sheet 51 is paid out from the finishing mill 52, and the steady speed is from the finishing mill 52 when the steel sheet 51 is at a constant speed after being accelerated. The rolling speed at the time of paying out and the final speed are the rolling speed at which the tail end of the steel plate 51 is discharged from the finishing mill 52 after the steel plate 51 is decelerated. Here, it is assumed that the steel plate 51 is accelerated in two stages, the first acceleration and the second acceleration, from the initial speed to the steady speed, and is decelerated in one stage from the steady speed to the final speed. It is going to be slowed down.

  In the example of the speed pattern table 22T of FIG. 3, for example, for the steel plate 51 having a steel type of SS400, a plate thickness of 1.4 mm or less, and a plate width of 1000 to 1400 mm, an initial speed of 650 mpm (meter per minute), 2 mpm A first acceleration of / s (meter per minute per second), a second acceleration of 12 mpm / s, a steady speed of 1050 mpm, a deceleration of 30 mpm / s, and an end speed of 900 mpm are associated with each other.

  FIG. 4 is a diagram showing an example of the configuration of the cooling header priority table 23T stored in the cooling header priority storage unit 23. As shown in FIG. 4, the cooling header priority table 23 </ b> T is configured by defining the order of the cooling header 61 that is preferentially opened for each steel type and thickness of the steel plate 51. That is, in the cooling header priority table 23T, the identification information of the cooling header 61 is defined for each priority order of 1 to 120 for each steel type and thickness of the steel plate 51. It is assumed that the priority is 1 is the highest and becomes lower as the priority increases.

  Here, the identification information of the cooling header 61 is composed of a set of two numerical values. The left numerical value of the set of two numerical values represents the identification number of the bank 60 (hereinafter referred to as bank number), and the right numerical value represents the identification number of the cooling header 61 in the bank 60 (hereinafter referred to as cooling header number). Represents). For example, the identification information (1, 2) of the cooling header 61 represents the second cooling header (cooling header number is 2) of the first bank (bank number is 1). Bank numbers and header numbers are numbered in ascending order from the side closer to the finishing mill 52.

  In the present embodiment, the configurations of the upper cooling device 58 and the lower cooling device 59 are vertically symmetrical, and the number of banks 60 and the number of cooling headers 61 are the same. In the following description, it is assumed that the number of banks 60 is 15 respectively, the number of cooling headers in each bank 60 is 8, and the total number of pairs of upper and lower cooling headers 61 is 120.

  The order of priority for opening the cooling header 61 as described above is information that is determined in advance in consideration of the cooling rate, cooling specifications, cooling efficiency, and the like required by the steel plate 51. For example, when the steel plate 51 is thin, a temperature difference hardly occurs between the surface and the inside of the steel plate 51. In that case, considering the cooling efficiency, the cooling header 61 close to the finishing mill 52 where the temperature of the steel plate 51 is high is preferentially opened. Therefore, a high priority is given to the cooling header 61 close to the finishing mill 52. On the other hand, when the steel plate 51 is thick, the temperature difference between the surface and the inside can be suppressed within the allowable range by using recuperation by air cooling. Therefore, priorities are given so that the open cooling headers 61 are not continuous as much as possible.

  By appropriately mixing water cooling and air cooling, the temperature difference between the surface and the inside of the steel plate 51 can be suppressed. For example, in the case of DP (Dual Phase) steel, since it is necessary to create a desired metal structure, a complicated cooling specification is applied. That is, in DP steel, in order to avoid precipitation of bainite and pearlite, the steel plate 51 is air-cooled for a certain period of time at an intermediate temperature, and then rapidly cooled immediately before winding by the downcoiler 55 in order to precipitate martensite. Therefore, the priority order of opening the cooling header 61 with respect to DP steel is set so as to be high in the cooling header 61 close to the finishing mill 52 and the downcoiler 55 and low in the cooling header 61 near the middle of both. Then, the cooling headers 61 are controlled so as to be opened as many as the target winding temperature can be achieved.

  In the example of FIG. 4, when the steel type is SS400 and the plate thickness is 1.2 to 1.8 mm, the cooling header 61 is (1,1), (1,2), (1,3), (1 , 4), (1, 5), (2, 1),..., (15, 7), (15, 8) in this order. That is, since the plate thickness is thin, the cooling efficiency is considered and the headers are opened preferentially in order from the header on the finishing mill 52 side. On the other hand, when the steel type is SS400 and the plate thickness is 3.2 to 4.2 mm, the cooling header 61 is (1,1), (1,4), (2,1), (2,4 ), (3, 1),..., (15, 5), (15, 8) in this order. That is, since the plate thickness of the steel plate 51 is somewhat thick, priority is given so that open headers do not continue.

  In the present embodiment, hereinafter, the cooling header 61 that is paired with the upper cooling device 58 and the lower cooling device 59 is given the same priority, and opening and closing is controlled by the same control code. Different priorities may be assigned to each, and the opening and closing may be controlled independently.

  FIG. 5 is a diagram showing an example of an opening / closing pattern of the cooling header 61 assigned to a control code used in the winding temperature control apparatus 100. As shown in FIG. 5, when the control code is 0, all the cooling headers 61 are closed. This represents air cooling over the entire winding cooling device 57. Conversely, when the control code is 120, all the cooling headers 61 are opened. This represents that the entire area of the winding cooling device 57 is water cooled.

  When the control code is 1, the cooling header 61 with the priority of 1 is opened and the others are closed. When the control code is 2, the cooling headers 61 with the priority orders 1 and 2 are opened and the others are closed. When the control code is 3, the cooling headers 61 with the priority orders 1 to 3 are opened and the others are closed. Hereinafter, similarly, an opening / closing pattern of the cooling header 61 is assigned.

  FIG. 6 is a diagram illustrating an example of a processing flow of preset cooling command calculation processing executed by the preset cooling command calculation unit 11. The preset cooling command calculation process calculates a control code corresponding to a header pattern for realizing a target winding temperature when the steel plate 51 is rolled according to a predetermined rolling schedule prior to cooling of the steel plate 51. It is processing.

  First, the preset cooling command calculation unit 11 acquires, from the speed pattern table 22T, data of rows corresponding to the steel type, plate thickness, and plate width of the steel plate 51 to be rolled. Then, based on the acquired row data, the first acceleration position, the second acceleration start position, the steady speed start position, the deceleration start position, and the deceleration completion position are calculated, and the speed pattern of the steel plate 51 being cooled is calculated ( Step S11).

Here, the first acceleration position SL _1s is the position of the steel plate 51 when the acceleration at the first acceleration specified by the speed pattern table 22T is started, and is calculated by the following equation (1).

SL _1s = L _sc (1)
Where L _{sc is a} constant

The second acceleration position SL _2s is a position of the steel plate 51 when acceleration at the second acceleration specified by the speed pattern table 22T is started, and is calculated by the following equation (2).

SL _2s = L _md (2)
However, L _md : Length from the finishing mill 52 exit side to the downcoiler 55

The steady speed start position SL _cs is the position of the steel sheet 51 when the steel sheet speed reaches the steady speed specified by the speed pattern table 22T, and is calculated by the following equation (3).

(V _1a ) ² = L _md · 2 · Acc ₁ + V _max · V _max
SL _cs = {L _md + (V _max −V _1a ) / Acc ₂ · (V _max + V _1a ) / 2} (3)
Where V _{1a is} the first acceleration end speed,
Acc ₁ : First acceleration, Acc ₂ : Second acceleration, V _max : Maximum speed

The deceleration start position SL _ds is the position of the steel plate 51 when deceleration at the deceleration specified by the speed pattern table 22T is started, and is calculated by the following equation (4).

SL _ds = ST _len − (V _max −V _f ) / Dcc · (V _max + V _f ) / 2−Dcc _mgn (4)
Where ST _len : length of the steel plate 51, V _f : final speed, Dcc: deceleration,
Dcc _mgn : How long before the bottom of the finish mill 52 is the steel plate 51
Margin for completing deceleration

The deceleration completion position SLde is the position of the steel plate 51 when the steel plate speed reaches the final speed indicated by the speed pattern table 22T and the deceleration ends, and is calculated by the following equation (5).
SLde = ST _len -Dcc _mgn (5)

  Subsequently, in the processing after step S12, for each of the steel plates 51 moving at the speed pattern calculated in step S11, the respective portions (when the steel plate 51 is divided into a predetermined length (for example, 5 m) in the longitudinal direction ( For each section), a header pattern for realizing the target winding temperature specified in the target winding temperature table 21T is calculated. Therefore, the preset cooling command calculation unit 11 selects sections of the steel plate 51 one by one in order from the tip (step S12). Then, the header code set for the selected section of the steel plate 51, that is, the control code of the cooling header 61 is calculated by the processing from step S13.

  Subsequently, a so-called linear inverse interpolation method is used for the process of calculating the control code of the cooling header 61 in step S13 and subsequent steps. Note that the linear inverse interpolation method in this case can be said to be a binary search method for an optimal solution. That is, in the processes of step S13 to step S17, an optimal control code for realizing the target winding temperature is calculated. Here, the optimal control code is a control code that realizes a temperature as close as possible to the target winding temperature, and is hereinafter referred to as a solution code.

In order to apply the linear inverse interpolation method, the preset cooling command calculation unit 11 first sets the initial values of the two control codes Cn _L and Cn _H (where Cn _L <Cn _H ) including the solution code therebetween, 0 and 120 are set (step S13). Here, Cn _L = 0 corresponds to a fully-closed header pattern, and Cn _H = 120 corresponds to a fully-open header pattern (see FIG. 5).

In the example of the control code shown in FIG. 5, the number of open cooling headers 61 monotonously increases as the value of the control code increases. In this case, T _c1 > T _c2 is established for the coiling temperatures T _c1 and T _c2 obtained corresponding to the header patterns of the control codes Cn _L and Cn _H (Cn _L <Cn _H ). Then, it can be determined that the solution code is between the two control codes Cn _L and Cn _H.

Therefore, the preset cooling command calculation unit 11 calculates a control code int {(Cn _L + Cn _H ) / 2} between the two control codes Cn _L and Cn _H as the temporary solution code Cn ₀ (step S14). Note that int represents a function for truncating the decimal part.

Next, the preset cooling command calculation unit 11 uses the plate temperature estimation model storage unit to calculate the coiling temperature predicted value T _c0 of the steel plate 51 when the steel plate 51 is cooled according to the header pattern corresponding to the temporary solution code Cn _0. It calculates using the plate temperature estimation model memorize | stored in 24 (step S15). In addition, the process (henceforth a coiling temperature prediction calculation process) which calculates _coiling temperature predicted value _Tc0 of step S15 is demonstrated in detail separately with reference to FIG.

Subsequently, the preset cooling command calculation unit 11 compares the winding temperature predicted value T _c0 calculated in step S15 with the target winding temperature T _target, and if T _c0 <T _target , Cn _H = Cn ₀ is set. In the case of T _c0 > T _target , Cn _L = Cn ₀ is set, and in the case of T _c0 = T _target , Cn ₀ becomes a solution code (step S16). The target winding temperature T _target is a target temperature given in the target winding temperature table 21T according to the steel type of the steel plate 51.

Here, a supplementary explanation will be given of the processing in step S16. If T _c0 <T _target , T _target is between T _c0 and T _c1 , so the solution code is between Cn _L and Cn ₀ . Therefore, Cn _H is updated by Cn ₀ (Cn _H = Cn ₀ ) for the next iteration. When T _c0 > T _target , T _target is between T _c2 and T _c0 , so the solution code is between Cn ₀ and Cn _H. Therefore, Cn _L is updated by Cn ₀ for the next iteration (Cn _L = Cn ₀ ).

Note that if T _c0 = T _target in step S16, the control code solution to be obtained is obtained, and the processing ends. However, in general, T _c0 = T _target due to a rounding error of the computer or the like. It is rare to become. Therefore, the preset cooling command calculation unit 11 determines whether or not the following end conditions (a) to (c) are satisfied in order to determine the end of the process (step S17).
(A) The number of times of repeating Step S14 to Step S16 has reached a predetermined number (for example, 8 times).
(B) The deviation between the _coiling temperature predicted value T _c0 and the target coiling temperature T _target is equal to or lower than a predetermined temperature (for example, 5 ° C.).
(C) The temporary solution code Cn ₀ matches Cn _L or Cn _H.

The preset cooling command calculation unit 11 determines the end conditions (a) to (c) described above, and if none of the end conditions is satisfied (No in step S17), the process returns to step S14. The processes after S14 are repeatedly executed. Further, the solution code Cn ₀ provisional if any of the conditions of termination condition is satisfied (Yes in step S17), the time (a) ~ (c), and the solution code in the section (Step S18).

  Then, the preset cooling command calculation unit 11 determines whether or not all sections have been selected in step S12 (step S19). If all sections have not been selected (No in step S19), The processing from step S12 onward is repeatedly executed. On the other hand, if all the sections have been selected (Yes in step S19), the preset cooling command calculation process ends.

FIG. 7 is a diagram showing an example of a detailed processing flow of the winding temperature prediction calculation process (step S14) in the preset cooling command calculation process of FIG. As shown in FIG. 7, in this process, the time from the tip of the steel plate 51 is discharged from the finishing mill 52 to the time when the tail end of the steel plate 51 passes through the winding thermometer 56 is timed at a constant time interval Δ. The steel plate 51 is moved in accordance with the speed pattern calculated in step S11 of FIG. 6 and the water is discharged from the cooling header 61 in accordance with the temporary solution code Cn ₀ obtained in step S13 of FIG. A predicted coiling temperature value T _c0 of 51 is calculated. That is, the coiling temperature prediction value T _c0 is obtained by subdividing the steel plate 51 between the finishing mill 52 and the coiling thermometer 56 in the longitudinal direction, and the movement amount for each time step for each of the subdivided parts. It is calculated based on the amount of heat released by air cooling or water cooling at each part.

First, the preset cooling command calculation unit 11 updates the current calculation time (hereinafter referred to as calculation time), and calculates the steel plate speed Vt at the calculation time from the speed pattern obtained in step S11 of FIG. 6 ( Step S21). Subsequently, the preset cooling command calculation unit 11 calculates the payout length Ln from the finishing mill 52 of the steel plate 51 at this time using the calculated steel plate speed Vt (step S22). The payout length Ln is the length of the steel plate 51 that has been rolled out and discharged from the finishing mill 52, and is calculated by the following equation (6).

Ln = Ln-1 + Δ · Vt (6)
However, Ln-1: Payout length at the previous calculation time

  Next, the preset cooling command calculation unit 11 determines whether or not the winding temperature prediction calculation process has been completed (step S23). That is, when the payout length Ln from the finishing mill 52 becomes larger than the total length of the steel plate 51 plus the distance from the finishing mill 52 to the winding thermometer 56, the winding temperature for one steel plate is predicted. The calculation is completed and the calculation is completed.

  If it is determined in step S23 that the calculation has not been completed (No in step S23), the preset cooling command calculation unit 11 performs temperature tracking of the steel sheet 51 (step S24). That is, in the temperature tracking, the preset cooling command calculation unit 11 obtains the distance traveled by the steel plate 51 when one step time Δ has elapsed from the previous and current payout lengths Ln-1 and Ln, and the exit side of the finishing mill 52 To the winding thermometer 56, the temperature distribution of the steel plate 51 is moved by the distance. At this time, the temperature of the steel plate 51 on the exit side of the finishing mill 52 is assumed to be a preset target temperature.

  Next, the preset cooling command calculation unit 11 specifies the corresponding section of the steel plate 51 for each cooling header 61 of the winding cooling device 57. Based on the control code assigned to the identified section and the priority of the cooling header 61 fetched from the cooling header priority table 23T, the open / close state of each cooling header 61 is determined (step S25).

  Here, the section of the steel plate 51 corresponding to each cooling header 61 basically means a section of the steel plate 51 located immediately below or directly above each cooling header 61. However, actually, there is a delay time of about 1 to 2 seconds from when the winding temperature control device 100 sends an opening / closing command to each cooling header 61 until the surface state of the steel plate 51 changes. Therefore, the corresponding section of the steel plate 51 is actually determined in consideration of this delay time.

  Next, the preset cooling command calculation unit 11 moves the steel plate 51 positioned from the exit side of the finishing mill 52 to the winding thermometer 56, for example, the nozzle pitch in the line direction of the cooling header 61 (the length direction of the steel plate 51). It is determined whether each part divided | segmented by (5) corresponds to water cooling or air cooling (step S26). In addition, the process after step S26 is performed by selecting the parts of the steel plates 51 divided as described above one by one.

Therefore, as a result of the determination in step S26, when it is determined that the part corresponds to water cooling (“water cooling” in step S26), the preset cooling command calculation unit 11 performs, for example, the following boundary condition of water cooling: The heat transfer coefficient hw is calculated according to equation (7) (step S27).

hw = 9.72 · 10 ⁵ · ω ^0.355 · {(2.5−1.15 · logTw) · D / (pl · pc)} ^0.646 /
(Tsu-Tw) (7)

Where ω is the water density (the amount of water received by the surface of the steel sheet 51 of unit area per unit time)
Tw: Water temperature (° C)
D: Nozzle diameter
pl: Nozzle pitch in the line direction (length direction of the steel plate 51)
pc: Nozzle pitch in the direction orthogonal to the line (the width direction of the steel plate 51)
Tsu: Surface temperature of the steel plate 51

  Equation (7) is a heat transfer coefficient in the case of so-called laminar cooling. There are various other water cooling methods such as spray cooling, and several heat transfer coefficient calculation formulas are known for each. Even if the cooling method is the same, the mathematical formula may reflect the latest experimental knowledge and may be different from each other.

On the other hand, when it is determined that the part corresponds to air cooling (“air cooling” in step S26), the preset cooling command calculation unit 11 performs heat transfer coefficient according to the following equation (8), for example, under the air cooling boundary condition: hr is calculated (step S28).

hr = σ · ε · [{(273 + Tsu) / 100} ⁴ − {(273 + Ta) / 100} ⁴ ] / (Tsu−Ta) (8)

Where σ: Stefan Boltzmann constant (= 4.88)
ε: Emissivity
Ta: Air temperature (° C)
Tsu: Steel plate surface temperature (steel plate temperature)

After calculating the heat transfer coefficients hw and hr in step S27 or step S28, the preset cooling command calculation unit 11 calculates the amount of heat transfer on the surface of the steel plate 51 and calculates the temperature of the part (step S29). . That is, the preset cooling command calculation unit 11 determines the temperature of the part of the steel plate 51 based on the temperature before the lapse of time Δ and the amount of heat moving during the time Δ, for example, It can be calculated according to 9).

Tn = Tn-1− (ht + hb) · Δ / (ρ · C · B) (9)

Tn: Current plate temperature
Tn-1: plate temperature before time Δ (steel plate temperature)
ht: Heat transfer coefficient of steel sheet surface
hb: Heat transfer coefficient on the back of the steel plate
ρ: Steel sheet density
C: Specific heat of steel plate
B: Steel plate thickness

Equation (9) ignores the heat transfer in the thickness direction of the steel plate 51, but when considering the heat conduction in the thickness direction of the steel plate 51, it is possible to use a well-known heat equation. it can. The thermal equation is represented by, for example, the following formula (3), and methods for calculating the difference with a computer are published in various technical literatures.

∂T / ∂t = {λ / ( ρ · C)} · (∂ 2 T / ∂x 2) (10)

Where λ: thermal conductivity
T: Steel plate temperature
x: Position in the thickness direction
t: time

  Next, the preset cooling command calculation unit 11 determines whether or not all the temperature calculations have been completed for each of the parts divided from the exit side of the finishing mill 52 of the steel plate 51 to the winding thermometer 56 (step S30). . As a result of the determination, if all the temperature calculations for each part have not been completed (No in step S30), the processes in and after step S26 are repeatedly executed.

  On the other hand, when all the temperature calculation of each part has been completed (Yes in step S30), the temperature of each part from the exit side of the finishing mill 52 of the steel sheet 51 to the winding thermometer 56 at a certain time, that is, A temperature distribution is obtained. This temperature distribution includes the predicted calculated temperature at the position of the winding thermometer 56. Therefore, the preset cooling command calculation unit 11 returns to step S21, advances the time by one time Δ, and repeatedly executes the processing after step S21.

  In step S23, when it is determined that the processing is completed, that is, the payout length Ln of the steel plate 51 from the finishing mill 52 is added to the entire length of the steel plate 51 by the distance from the finishing mill 52 to the winding thermometer 56. When it becomes larger than the value, the winding temperature prediction calculation process is terminated.

  FIG. 8 is a diagram showing an example of a process in which the control code is optimized in the preset cooling command calculation process of FIG. In the repetitive processing of step S14 to step S17 in FIG. 6, the control code for the cooling header 61 that is optimal for realizing the target winding temperature is obtained, but in FIG. It shows how it is optimized. Here, it is assumed that the control code is calculated for each part (section) obtained by dividing the steel plate 51 in units of 5 m in the length direction.

As shown in FIG. 8, in the first iteration, each part (section) has the same initial value (Cn _L = 0, Cn _H = 120: see step S13 in FIG. 6) as the simplest method. Given. As a result, in the first iteration, the provisional solution code Cn ₀ is Cn ₀ = 60 for all parts as shown in the control code column of FIG.

In the second iteration, the predicted calculation result of the coiling temperature predicted value T _c0 of each part of the steel sheet 51 when the steel sheet 51 is cooled with the header pattern corresponding to the control code Cn ₀ = 60 is the target coiling temperature T. _The control code used in the next iteration is different depending on whether it is larger or smaller than _target . In the example of FIG. 8, the control code in the direction in which the cooling header 61 is closed is updated at a portion near the tip and tail ends of the steel plate 51 where the steel plate speed is low, and at the central portion of the steel plate 51 where the steel plate speed is high. The control code is updated to the direction in which the cooling header 61 is opened.

Specifically, in the part near the front end and the rear end of the steel plate 51, since it is updated to Cn _L = 0 and Cn _H = 60 in step S15 of the first repetition process, the provisional obtained in the second repetition process. The solution code of Cn ₀ = 30. On the other hand, in the central part of the steel plate 51 (parts of 500 to 505 m and 505 to 510 m in FIG. 8), Cn _L = 60 and Cn _H = 120 are updated in step S15 of the first iteration. Therefore, the temporary solution code obtained in the second iteration is Cn ₀ = 90.

In this way, by repeating steps S14~ step S17 in FIG. 6, the solution code Cn ₀ provisional of each part of the steel plate 51 is updated. Then, the solution code Cn ₀ of each part of the steel plate 51 when the repetition process is completed is adopted as a control code, that is, a solution code, that realizes the winding temperature closest to the target winding temperature T _target . In the example of FIG. 8, the solution code of the part 5 m from the tip of the steel plate 51 is “37”, the solution code of the part 5 to 10 m is “38”,..., And the solution code of the part 500 to 505 m is , “72”,..., The solution code of the tail end portion is “46” or the like.

FIG. 9 is a diagram illustrating an example of a processing flow of an influence coefficient calculation process executed by the influence coefficient calculation unit 12. As shown in FIG. 9, the influence coefficient calculation unit 12 first calculates an average steel sheet for a predetermined calculation point of the steel sheet 51 until the part is discharged from the finishing mill 52 and wound by the downcoiler 55. After specifying the reference steel plate speed Vs, which is the speed, and the coiling temperature CTt, a material prediction process (see FIG. 10) is executed (step S41). As a result of the treatment, tensile strength γ ₁ , hardness H ₁ , and ductility E ₁ which are material characteristics of the steel plate 51 after cooling are obtained (step S42). Here, as a value representative of the reference steel plate speed Vs, the roll peripheral speed of the work roll 54 of the rolling stand 53 can be used. Alternatively, as a stricter value, a value obtained by multiplying the roll peripheral speed by the advanced rate that is the ratio of the roll peripheral speed and the exit side plate speed may be used.

Next, the influence coefficient calculation unit 12 sets Vs + ΔV obtained by increasing the reference steel plate speed Vs by ΔV as the reference steel plate speed Vs, specifies the coiling temperature CTt, and causes the material prediction unit 13 to execute the material prediction process (step S43). ). Then, as the processing result, tensile strength γ ₂ , hardness H ₂ , and ductility E ₂ when the reference steel plate speed Vs is increased by ΔV are obtained (step S44).

Next, the influence coefficient calculation unit 12 calculates a first influence coefficient defined by the following equations (11-1), (11-2), and (11-3). That is, the change rate of tensile strength γ (∂γ / ∂V), change rate of hardness (∂H / ∂V), and change rate of ductility (∂E / ∂V) with respect to change amount ΔV of reference steel plate speed Vs. Calculate (step S45).

(∂γ / ∂V) = (γ ₂ −γ ₁ ) / ΔV (11-1)
(∂H / ∂V) = (H ₂ −H ₁ ) / ΔV (11-2)
(∂E / ∂V) = (E ₂ −E ₁ ) / ΔV (11-3)

Next, the influence coefficient calculation unit 12 specifies the reference steel plate speed Vs, further increases the coiling temperature CTt by ΔCTt, and sets CTt + ΔCTt as a new coiling temperature CTt, and then performs a material prediction process on the material prediction unit 13. (Step S46). Then, as the processing result, tensile strength γ ₃ , hardness H ₃ , and ductility E ₃ when the winding temperature CTt is increased by ΔCTt are obtained (step S47).

Next, the influence coefficient calculation unit 12 calculates a second influence coefficient defined by the following equations (12-1), (12-2), and (12-3). That is, the rate of change in tensile strength γ (∂γ / ∂CT), the rate of change in hardness (∂H / お よ び CT), and the rate of change in ductility (∂E / ∂CT) with respect to the change amount ΔCTt of the coiling temperature CTt. Calculate (step S48).

(∂γ / ∂CT) = (γ ₃ −γ ₁ ) / ΔCTt (12-1)
(∂H / ∂CT) = (H ₃ −H ₁ ) / ΔCTt (12-2)
(∂E / ∂CT) = (E ₃ −E ₁ ) / ΔCTt (12-3)

  Next, the influence coefficient calculation unit 12 uses the formulas (11-1), (11-2), (11-3), and (12-1) at all the predetermined calculation points in the longitudinal direction of the steel plate 51. , (12-2) and (11-3), it is determined whether or not the calculation of the first and second influence coefficients has been completed (step S49). As a result of the determination, when the calculation of these influence coefficients is not completed at all the calculation points (No in step S49), the processes of steps S41 to S49 are repeatedly executed for the incomplete calculation points. If the calculation of the first and second influence coefficients has been completed at all the calculation points (Yes in step S49), the influence coefficient calculation process is terminated.

  As calculation points, three points of the tip, the center, and the tail end can be selected corresponding to the speed change of the steel plate 51. In addition, for simplicity, a single point (for example, the center) representing the longitudinal direction of the steel plate 51 may be used. Furthermore, the calculation points may be increased in a thin plate having a large speed change (for example, the steel plate 51 having a thickness of the rolled steel plate 51 of about 1.8 mm or less), and the calculation points may be reduced in a thick plate. Hereinafter, in this embodiment, the calculation point is assumed to be one point at the tip of the steel plate 51 in order to avoid complicated description.

  FIG. 10 is a diagram illustrating an example of a processing flow of the material prediction process executed by the material prediction unit 13. The material prediction process is started in the influence coefficient calculation process shown in FIG. 9, is wound up by the downcoiler 55, predicts and calculates the tensile strength γ, hardness H, and ductility E of the steel sheet 51 after cooling, and calculates the calculation result. This is a process of reporting to the influence coefficient calculation unit 12.

  As shown in FIG. 10, the material predicting unit 13 first obtains the reference steel plate speed Vs and the coiling temperature CTt specified by the influence coefficient calculating process (see FIG. 9) of the influence coefficient calculating unit 12 (step S51). . Next, in addition to the rolling schedule of the steel plate 51, the material predicting unit 13 acquires various history information obtained by finishing rolling, rough rolling, or the like, which is a previous process of the cooling process, from the host computer 40 (step S52). . Furthermore, the material predicting unit 13 acquires a temperature change of the steel plate 51 being predicted and calculated by the preset cooling command calculating unit 11 (step S53). Subsequently, when the steel plate 51 is cooled at the reference steel plate speed Vs and the coiling temperature CTt specified by the influence coefficient calculation process (see FIG. 9), the material predicting unit 13 has the tensile strength γ and hardness of the steel plate 51 at room temperature. H and ductility E are predicted and output to the influence coefficient calculator 12 (step S54).

  The tensile strength γ, hardness H, and ductility E of the steel sheet 51 at room temperature after cooling, in addition to the steel type and chemical composition of the steel sheet 51, heating history before rolling, temperature drop history after heating, rolling temperature, deformation during rolling It can be calculated by using information such as speed and temperature drop behavior during winding cooling. However, the explanation of the calculation formula and calculation method is omitted, but for details, for example, “Material Function Creation FEM Analysis Technology Study Group Report” June 2001 (Japan Iron and Steel Institute, Production Technology Division, Rolling Theory) Subcommittee Material Function Creation FEM Analysis Technology Study Group).

  FIG. 11 is a diagram illustrating an example of a processing flow of a winding temperature correction amount calculation process executed by the winding temperature correction amount calculation unit 31. As shown in FIG. 8, the winding temperature correction amount calculation unit 31 first obtains the roll speed of the rolling stand 53 at the final stage of the finishing mill 52 from the control object 50, and the change amount ΔV from the reference steel plate speed Vs. Is calculated (step S61).

Next, the winding temperature correction amount calculation unit 31 reduces the change in the tensile strength γ of the steel plate 51 with respect to the speed change of the steel plate 51 and maintains the tensile strength γ at a uniform value in the longitudinal direction of the steel plate 51. calculates a correction amount [Delta] CT _gamma temperature CT _gamma (step S62). Similarly, the winding temperature correction amount calculation unit 31 reduces the change in the hardness H of the steel plate 51 with respect to the speed change of the steel plate 51 and takes up the winding for maintaining the change in the hardness H at a uniform value in the longitudinal direction of the steel plate 51. It calculates a correction amount [Delta] CT _H of temperature CT _H (step S63). Further, similarly, the coiling temperature correction amount calculation unit 31 reduces the change in the ductility E of the steel plate 51 with respect to the speed change of the steel plate 51, and maintains the change in the ductility E at a uniform value in the longitudinal direction of the steel plate 51. It calculates a correction amount [Delta] CT _E of coiling temperature CT _E (step S64).

These correction amounts ΔCT _γ , ΔCT _H , and ΔCT _E are calculated according to the following equations (13-1), (13-2), and (13-3).

ΔCT _γ = (∂γ / ∂V) / (∂γ / ∂CT) · ΔV (13-1)
ΔCT _H = (∂H / ∂V) / (∂H / ∂CT) · ΔV (13-2)
ΔCT _E = (∂E / ∂V) / (∂E / ∂CT) · ΔV (13-3)

Next, the winding temperature correction amount calculation unit 31 calculates a correction amount ΔCTt of the winding temperature CTt for integrating and equalizing the tensile strength γ, the hardness H, and the ductility E according to the following equation (14). (Step S65).

ΔCTt = α ₁ · ΔCT _γ + α ₂ · ΔCT _H + α ₃ · ΔCT _E (14)
However, α ₁ , α ₂ , α ₃ are 0 or a positive constant satisfying α ₁ + α ₂ + α ₃ = 1.

Here, α ₁ , α ₂ , and α ₃ are constants that give the ratio of how much to consider each of the tensile strength γ, hardness H, and ductility E with respect to the influence of the change in the steel plate speed on the material properties. . When α ₁ is 1 (others are 0), the winding temperature correction amount ΔCT _γ is calculated so that the tensile strength γ is constant. Also, alpha ₂ when _(others 0) is 1, the correction amount [Delta] CT _H winding temperature as the hardness H is constant is calculated. Further, when the alpha ₃ is 1 (the other is 0), the correction amount [Delta] CT _E of the winding temperature as ductility E is constant is calculated. When α _{1 to} α ₃ are intermediate values of 0 to ₁ , according to the values of α _{1 to} α ₃ , the degree of tensile strength γ, hardness H, and ductility E is apportioned and uniformly made uniform.

  Finally, the winding temperature correction amount calculation unit 31 outputs the winding temperature correction amount ΔCTt calculated in step S65 to the feedforward control unit 32 and the winding temperature command calculation unit 33 (step S66). The temperature correction amount calculation process ends.

  FIG. 12 is a diagram illustrating an example of a processing flow of a winding temperature command calculation process executed by the winding temperature command calculation unit 33. The winding temperature command calculation unit 33 uses the winding temperature CTt received via the preset cooling command calculation unit 11 and the winding temperature correction amount ΔCTt received from the winding temperature correction amount calculation unit 31 for control. The control target winding temperature CTtc to be used is calculated in real time during the cooling control, and the calculation result is output to the feedback control unit 34.

Therefore, the winding temperature command calculation unit 33 first acquires the winding temperature CTt from the preset cooling command calculation unit 11 (step S71), and further, the winding temperature correction amount ΔCTt from the winding temperature correction amount calculation unit 31. Is acquired (step S72). Subsequently, the winding temperature command calculation unit 33 calculates the control target winding temperature CTtc in real time during the cooling control according to the following equation (15) (step S73).

CTtc = CTt + β · ΔCTt (15)
Where β: correction gain (0 to 1)

  Next, the winding temperature command calculation unit 33 outputs the control target winding temperature CTtc obtained by this calculation formula to the feedback control unit 34 (step S74), and ends the control command temperature calculation process.

The feedforward control unit 32 (illustration of the processing flow is omitted) acquires the winding temperature correction amount ΔCTt from the winding temperature correction amount calculation unit 31, and the actual winding temperature of the steel plate 51 corresponds to the correction amount ΔCTt. Then, the control code change amount ΔN _FF is calculated. The change amount ΔN _FF of the control code is calculated by the following equation (16), for example.

ΔN _FF = a ₁ · (∂N / ∂CT) · ΔCTt (16)
Where a ₁ : control gain

Note that (∂N /） CT) is an influence coefficient representing a control code for canceling the change in the winding temperature CTt, and is a constant.

Further, the feedback control unit 34 (illustration of the processing flow is omitted) takes in the measured temperature CTa of the steel plate 51 from the winding thermometer 56, and the control target winding acquired from the measured temperature CTa and the winding temperature command calculating unit 33. A control code change amount ΔN _FB for eliminating the deviation ΔCTa from the temperature CTtc is calculated. The change amount ΔN _FB of the control code is calculated by the following equation (17), for example.

ΔN _FB = a ₂ · (∂N / ∂CT) · ΔCTa (17)
Here, ΔCTa = CTtc−CTa
a ₂ : Control gain

  FIG. 13 is a diagram illustrating an example of a processing flow of a cooling header command calculation process executed by the cooling header command calculation unit 35. The cooling header command calculation unit 35 calculates the control code obtained by the calculation before the cooling by the preset cooling command calculation unit 11 and the control code change amount calculated by the feedforward control unit 32 and the feedback control unit 34. Correct with the amount of control code change. Then, the corrected control code is converted into a header pattern that is finally output to the winding cooling device 57, and the converted header pattern is output to the winding cooling device 57.

Cooling header command calculation unit 35, a preset value Nps _i for each site control code that is calculated corresponding to (section i) of the steel sheet 51 is obtained from a preset cooling command calculation unit 11 (step S81). Next, the cooling header command calculation unit 35 acquires the control code change amount ΔN _FF at the time of feed forward from the feed forward control unit 32 (step S82), and further feeds back the control code change amount ΔN _FB at the time of feedback. Obtained from the control unit 34 (step S83).

Subsequently, the cooling header command calculation unit 35 corrects the preset value Nps _i of the control code with the control code change amount ΔN _FF at the time of feedforward and the control code change amount ΔN _FB at the time of feedback, and the following equation (18 ), The control code Nct _i used for actual control is obtained (step S84).

Nct _i = Nps _i + ΔN _FF + ΔN _FB (18)
Where i: Section number of the steel plate 51

As shown in the following equation (19), the control code Nct _i is calculated by assigning weights w ₁ and w ₂ to the control code changes ΔN _FF and ΔN _FB at the time of feedforward and feedback, respectively. It may be attached and calculated.

Nct _i = Nps _i + w ₁ · ΔN _FF + w ₂ · ΔN _FB (19)
Here, w ₁ and w ₂ are 0 or a positive constant that satisfies w ₁ + w ₂ = 1.

Subsequently, the control code Nct _i is converted into a header pattern to be output to the winding cooling device 57 by the following processing. This process is performed for all the cooling headers 61 provided in the winding cooling device 57.

  First, the cooling header command calculation unit 35 selects one of the cooling headers 61 (a pair of upper and lower sides), and calculates a distance Lh from the tip of the steel plate 51 passing directly under the cooling header 61 (step S85). . The winding temperature control device 100 has a function of detecting the distance from the front end of the steel plate 51 at the exit side position of the finishing mill 52, for example, for the purpose of specifying the steel plate position. Can be easily calculated.

Next, the cooling header command calculation unit 35 determines whether or not the distance Lh is smaller than 0 (step S86). As a result of the determination, if the distance Lh is smaller than 0 (Yes in step S86), the tip of the steel plate 51 has not reached the cooling header 61, so the process of step S87 and step S89 is skipped, and the process of step S89 is performed. Proceed to processing. On the other hand, when the distance Lh is equal to or greater than 0 (Yes in step S86), since the leading end of the steel plate 51 has reached the cooling header 61, the cooling header command calculation unit 35 determines the steel plate 51 corresponding to the distance Lh. The control code Nct _i of the section is acquired (step S87). That is, the control code Nct _i corresponding to the part having the length Lh from the tip of the steel plate 51 is acquired.

Next, the cooling header command calculation unit 35 determines opening / closing of the cooling header 61 (step S88). That is, when the priority of the cooling header 61 is equal to or smaller than the acquired control code Nct _i , the cooling header 61 is set to “open”, and otherwise, it is set to “closed”. And the cooling header command calculation part 35 determines whether the opening / closing was determined about all the cooling headers 61 (step S89). As a result of the determination, if opening / closing has not been determined for all the cooling headers 61 (No in step S89), the process returns to step S85, and the processes in and after step S85 are repeated.

  On the other hand, when the opening / closing of all the cooling headers 61 has been determined (Yes in step S89), the cooling header command calculation unit 35 winds the determined opening / closing information (header pattern) of the cooling header 61. It outputs to the cooling device 57 (step S90), and the said cooling header command calculation process is complete | finished.

  As described above, in the present embodiment, the change rate of the material property (first influence coefficient) with respect to the change from the reference steel plate speed Vs at the time of cooling and winding, and the change rate of the material property with respect to the change of the winding temperature CTt (second Influence coefficient) and using the relationship between the two, if there is a change in the material characteristics due to the change in the reference steel plate speed Vs, the change in the material characteristics is caused by the change in the coiling temperature CTt. It is designed to be countered. Therefore, the material properties of the steel plate 51 can be kept constant even if the reference steel plate speed Vs during cooling and winding varies. Therefore, the winding temperature control apparatus 100 according to the present embodiment has an effect that the uniformity of the material properties in the longitudinal direction of the steel plate 51 that is rolled and wound around the downcoiler 55 can be improved.

  In the embodiment described above, the tensile strength γ is adopted as the strength of the steel plate 51, but it is not limited to the tensile strength, and yield strength, compressive strength, shear strength, and the like may be adopted. In addition to strength γ, hardness H, and ductility E, quantities representing material characteristics include brittleness (brittleness), grindability, wear resistance, workability, and the like. The material predicting unit 13 may calculate the influence coefficient by predicting these amounts in a predictable range. In such an embodiment, the material characteristics (brittleness, grindability, wear resistance, workability, etc.) can be made uniform in the longitudinal direction of the steel plate 51.

  In the embodiment described above, the material prediction process and the influence coefficient calculation process are executed each time for the steel sheet 51 to be rolled and then cooled, but the influence coefficient once obtained is determined at that time. You may memorize | store in a memory | storage device corresponding to conditions, such as a steel type, board thickness, board width, target winding temperature, a speed pattern, and a heating history. When another steel plate 51 is rolled and cooled, if an influence coefficient that matches the condition is stored in the storage device, it is stored without performing the material prediction process and the influence coefficient calculation process. May be used.

  The present invention is not limited to the embodiment described above, and includes various modifications. The above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to one having all the configurations described. Further, a part of the configuration of an embodiment can be replaced with a part of the configuration of another embodiment, and further, a part or all of the configuration of the other embodiment is added to the configuration of the certain embodiment. Is also possible.

10 Preset Control Unit 11 Preset Cooling Command Calculation Unit (First Cooling Command Calculation Unit)
DESCRIPTION OF SYMBOLS 12 Influence coefficient calculation part 13 Material prediction part 21 Target winding temperature memory | storage part 21T Target winding temperature table 22 Speed pattern memory | storage part 22T Speed pattern table 23 Cooling header priority order memory | storage part 23T Cooling header priority order table 24 Sheet temperature estimation model memory | storage Unit 30 Dynamic control unit 31 Winding temperature correction amount calculating unit 32 Feed forward control unit 33 Winding temperature command calculating unit 34 Feedback control unit 35 Cooling header command calculating unit (second cooling command calculating unit)
40 Host computer 50 Control object 51 Steel plate 52 Finishing mill 53 Rolling stand 54 Work roll 55 Downcoiler 56 Winding thermometer 57 Winding cooling device (cooling device)
58 Upper cooling device 59 Lower cooling device 60 Bank 61 Cooling header 100 Winding temperature control device

Claims (10)

A plurality of cooling headers that open and close the nozzles according to a cooling header opening / closing command are provided, and the steel plates are cooled by discharging water from the cooling header at a position before the steel plates discharged from the hot rolling finishing mill are wound by the downcoiler. A cooling temperature control device for the cooling device,
Prior to cooling the steel plate, the steel sheet predicts a winding temperature of the steel plate when passing through the cooling device at a preset steel plate speed, and the predicted winding temperature is set to a preset target winding. A first cooling command calculation unit that calculates the cooling header opening / closing command that substantially matches the intake temperature;
When the steel plate is cooled by the cooling device, the steel plate speed of the steel plate is detected, and the correction amount of the coiling temperature for keeping the material of the steel plate constant according to the change in the steel plate speed is determined. A winding temperature correction amount calculation unit to calculate,
The cooling headers switching command calculated by the first cooling command calculator, have to correct use of the control amount obtained based on the correction amount of the winding temperature calculated by the winding temperature correction amount calculating section A second cooling command calculation unit that outputs the corrected cooling header opening / closing command to the cooling device;
A winding temperature control device comprising: Based on information including the chemical composition of the steel sheet received from the host computer, rolling and cooling history of the steel sheet, a material prediction unit that calculates at least one of the strength, hardness and ductility of the steel sheet as a material characteristic value;
Based on the material property value calculated by the material predicting unit, the influence of the change amount of the steel plate speed on the material property value is calculated as a first influence coefficient, and the change amount of the winding temperature is the material property value. An influence coefficient calculation unit for calculating the influence on the value as the second influence coefficient;
Further comprising
The winding temperature correction amount calculation unit
And the variation of the steel sheet speed, the a first influence coefficient, the second by using the influence coefficient, winding according to claim 1, characterized in that to calculate the correction amount of the winding temperature Temperature control device. A feedforward control unit that calculates, as a feedforward control amount, a change amount of the cooling header open / close command that cancels the correction amount of the winding temperature calculated by the winding temperature correction amount calculation unit;
The second cooling command calculator is
The winding temperature control device according to claim 1 , wherein the feedforward control amount is used as the control amount used when correcting the cooling header open / close command calculated by the first cooling command calculation unit. . A winding for calculating a control target winding temperature based on the correction amount of the winding temperature calculated by the winding temperature correction amount calculation unit and the target winding temperature used by the first cooling command calculation unit. Taking temperature command calculation part,
Feedback control section for calculating a change amount of the cooling headers switching command such as to reduce the difference between the actual measurement value of the winding temperature command calculator the control target coiling temperature calculated by said coiling temperature as a feedback control amount When,
In addition,
The second cooling command calculator is
The winding temperature control apparatus according to claim 1 , wherein the feedback control amount is used as the control amount used when correcting the cooling header opening / closing command calculated by the first cooling command calculating unit. A feedforward control unit that calculates a change amount of the cooling headers switching command to cancel the correction amount of the winding temperature calculated in the winding temperature correction amount calculating unit as a feedforward control amount,
A winding for calculating a control target winding temperature based on the correction amount of the winding temperature calculated by the winding temperature correction amount calculation unit and the target winding temperature used by the first cooling command calculation unit. Taking temperature command calculation part,
Feedback control for calculating the change amount of the cooling headers switching command such as to reduce the difference between the actual measurement value of the winding temperature command calculator the control target coiling temperature calculated by said coiling temperature as a feedback control amount And
In addition,
The second cooling command calculator is
The control amount used when correcting the cooling header opening / closing command calculated by the first cooling command calculation unit is obtained by weighting and adding each of the feedforward control amount and the feedback control amount. The winding temperature control device according to claim 1, wherein the correction is performed using a control amount. A plurality of cooling headers that open and close the nozzles according to a cooling header opening / closing command are provided, and the steel plates are cooled by discharging water from the cooling header at a position before the steel plates discharged from the hot rolling finishing mill are wound by the downcoiler. A winding temperature control method for controlling a cooling device to be performed by a computer,
The computer
Prior to cooling the steel plate, the steel sheet predicts a winding temperature of the steel plate when passing through the cooling device at a preset steel plate speed, and the predicted winding temperature is set to a preset target winding. A first cooling command calculation step for calculating the cooling header opening / closing command that substantially matches the intake temperature;
When the steel plate is cooled by the cooling device, the steel plate speed of the steel plate is detected, and the correction amount of the coiling temperature for keeping the material of the steel plate constant according to the change in the steel plate speed is determined. A winding temperature correction amount calculating step to calculate,
The cooling headers switching command calculated by the first cooling command calculating step, have to correct use of the control amount obtained based on the correction amount of the winding temperature correction amount calculating the winding temperature calculated in step A second cooling command calculation step of outputting the corrected cooling header opening / closing command to the cooling device;
The winding temperature control method characterized by performing this. The computer
Based on information including the chemical composition of the steel sheet received from the host computer, rolling and cooling history of the steel sheet, a material prediction step for calculating at least one of the strength, hardness and ductility of the steel sheet as a material characteristic value;
Based on the material characteristic value calculated in the material prediction step, the influence of the change amount of the steel plate speed on the material characteristic value is calculated as a first influence coefficient, and the change amount of the coiling temperature is the material characteristic. and influence coefficient calculating step of calculating as the effect on the value second influence coefficient,
Run further,
In the winding temperature correction amount calculating step,
And the variation of the steel sheet speed, the a first influence coefficients, by using the second influence coefficient, winding according to claim 6, characterized in that to calculate the correction amount of the winding temperature Taking temperature control method. The computer
Further executing a feedforward control step of calculating a change amount of the cooling header opening / closing command as a feedforward control amount so as to cancel the correction amount of the winding temperature calculated in the winding temperature correction amount calculating step;
In the second cooling command calculation step,
The winding temperature control method according to claim 6 , wherein the feedforward control amount is used as the control amount used when correcting the cooling header open / close command calculated in the first cooling command calculation step. . The computer
A winding for calculating a control target winding temperature based on the correction amount of the winding temperature calculated in the winding temperature correction amount calculation step and the target winding temperature used in the first cooling command calculation step. Taking temperature command calculation step,
A feedback control step of calculating a change amount of the cooling header open / close command as a feedback control amount so as to reduce a difference between the control target winding temperature calculated in the winding temperature command calculating step and the actual measured value of the winding temperature. When,
Run further,
In the second cooling command calculation step,
The winding temperature control method according to claim 6 , wherein the feedback control amount is used as the control amount used when correcting the cooling header open / close command calculated in the first cooling command calculation step. The computer
A feed forward control step of calculating a change amount of the cooling headers switching command to cancel the correction amount of the calculated at a coiling temperature correction amount calculating step the winding temperature as a feedforward control amount,
A winding for calculating a control target winding temperature based on the correction amount of the winding temperature calculated in the winding temperature correction amount calculation step and the target winding temperature used in the first cooling command calculation step. Taking temperature command calculation step,
Feedback control for calculating the change amount of the cooling headers switching command such as to reduce the difference between the actual measurement value of the winding temperature command calculating the control target coiling temperature calculated in step and the coiling temperature as a feedback control amount Steps,
Run further,
In the second cooling command calculation step,
The control amount used when correcting the cooling header opening / closing command calculated in the first cooling command calculation step is obtained by adding a weight to each of the feedforward control amount and the feedback control amount. The winding temperature control method according to claim 6, wherein correction is performed using a control amount.

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