JP2000326004A - Method and device of controlling plate thickness for twin-drum type continuous casting equipment and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely and accurate control a plate thickness of a hot band whose plate thickness varies rapidly and minutely. SOLUTION: A gain adjustment specific to a hot band is surely realized by providing a characteristic information of the relation between the ratio of a plasticity coefficient at a point, where a plate thickness variation takes place to a plasticity coefficient at a uniform section where a plate thickness variation does not take place, and the deviation of a plate thickness at the feeding side of a rolling mill 9, and by enabling the plasticity coefficient of a hot band, whose plate thickness varies rapidly and slightly, to be derived from the plate thickness by a calculation of correction factor of the rolling position of a rolling mill 9, based on the plate thickness measured with a plate thickness measuring device 5 located at the feeding side of the rolling mill 9 and on the characteristic information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for controlling the thickness of a twin-drum continuous casting facility, and more particularly to a recording medium storing a program for realizing the same by a software function.

[0002]

2. Description of the Related Art Conventionally, in a process of automatically controlling a sheet thickness to a target value by a hot rolling mill after a continuous casting process for processing a molten metal (molten steel) into a plate shape, the rolling mill is made of a material. Generally, there is a method of adjusting the rolling position (roll gap) based on the magnitude of the reaction force applied to the rolling roll when passing, and a method of adjusting the rolling position based on the sheet thickness measured at the entrance or exit of the rolling mill. Used. Further, a method of adjusting the gain of these automatic controls according to the plate temperature has also been proposed.

[0003] For example, Japanese Patent Application Laid-Open No. 62-45419 discloses an automatic thickness control of a hot tandem rolling mill.
The sheet temperature measured by a thermometer installed on the entrance side of the stand is tracked with the movement of the rolled material, and the temperature part lowered by air cooling or coolant and the temperature part raised by rolling are compensated, and the sheet immediately before each rolling stand is compensated. Predict the temperature. Then, an example is shown in which the plastic coefficient (hardness of the sheet) of the rolled material is determined according to the predicted sheet temperature, and the gain of the automatic sheet thickness control is calculated.

[0004] As one of continuous casting facilities for processing the molten metal into a plate, there is a twin-drum strip continuous casting facility (STC). FIG. 6 shows an example of the configuration. As shown in FIG. 6, in the twin-drum continuous casting facility, a pair of cooling drums 1 arranged in parallel with each other at a predetermined interval, and arranged in a state of being pressed against both side surfaces of these cooling drums 1. A continuous casting mold is constituted by the pair of side dams 52 provided.

[0005] A molten metal (molten steel) 54 such as iron or aluminum stored in a preheating layer called a tundish 53 is continuously poured into the continuous casting mold to form a pool 55. The molten metal 54 in contact with the cooling drum 1 is thinly solidified on the surface of the cooling drum 1.

[0006] By rotating the pair of cooling drums 1 whose surfaces are solidified with metal as shown by arrows, a strip-shaped slab 2 is formed from the thinly solidified metal and sent downward. A predetermined amount of molten metal 54 is always supplied to the tundish 53 from a molten steel pot 57 called a ladle while the supply amount is adjusted by a stepping cylinder 58.

[0007]

However, in such a twin-drum continuous casting facility, the molten metal 54 injected between the two cooling drums 1 is solidified by the side weir 52 and the like, and the solidified metal pieces are removed. Hot water pool 5 from side weir 52
5, a phenomenon of mixing in the strip-shaped slab 2 occurs. In general, the portion where the metal pieces are mixed is
Compared with other parts of the slab, the plate thickness is large and the plate temperature is high at the same time. Such a part is called a "hot band".

As shown in FIG. 7, the fluctuation of the sheet thickness H and the sheet temperature in the hot band is steep, and the time range W generated in the line direction is extremely small. Are quite different. Therefore, in the conventional automatic thickness control method, it is difficult to control the thickness accurately with respect to the above-described rapid variation in the thickness. Therefore, in the hot band portion, it is necessary to adjust the gain of the rolling mill by obtaining a plastic coefficient specific to the hot band.

However, Japanese Unexamined Patent Application Publication No.
The conventional plate thickness control method including the method disclosed in Japanese Patent No. 45419 cannot cope with a steep plate thickness variation occurring in twin-drum continuous casting. That is, since the hot band is extremely steep and the time range W in which it occurs is extremely short, the conventional method has problems in response delay and control accuracy.

When the speed of conveying the slab on the line is reduced, the time range W with respect to the line direction in which the hot band is generated can be lengthened. However, the production efficiency is deteriorated, and the slab is reduced by air cooling or the like. It is not preferable to reduce the transport speed due to various circumstances such as the unnecessary temperature drop occurring.

The present invention has been made in view of the above circumstances, and has a high-precision gain adjustment for a hot band having a sharp and minute thickness fluctuation by performing a gain adjustment specific to the hot band. It is an object of the present invention to ensure that thickness control can be performed.

[0012]

According to the present invention, there is provided a method for controlling a thickness of a twin-drum continuous casting machine, wherein a rolled material cast by the twin-drum continuous casting machine is rolled by a rolling mill to control the thickness thereof. In the sheet thickness control method, the ratio of the plastic coefficient of the sheet thickness fluctuation part and the plastic coefficient of the steady part without the sheet thickness fluctuation, and the deviation from the sheet thickness or the target sheet thickness of the rolled material on the entrance side of the rolling mill, Alternatively, it has characteristic information indicating the relationship between the sheet temperature or the deviation with respect to the target sheet temperature, and the sheet thickness or sheet temperature measured by the sheet thickness measuring means or sheet temperature measuring means installed on the entrance side of the rolling mill, and The rolling position of the rolling mill is controlled by calculating the rolling position correction amount of the rolling mill based on the characteristic information.

In another aspect of the present invention, based on the characteristic information, the plasticity coefficient is obtained from a sheet thickness or a sheet temperature measured by a sheet thickness measuring means or a sheet temperature measuring means installed on the entrance side of the rolling mill. The ratio is determined, and the rolling position correction amount of the rolling mill with respect to the sheet thickness variation portion is calculated using the determined plastic coefficient ratio.

In another aspect of the present invention, only when the variation of the sheet thickness in the sheet thickness variation section exceeds a reference value, the calculation of the rolling position correction amount based on the characteristic information is performed. . In addition, the plate thickness measured by the plate thickness measuring means is tracked together with the movement of the rolled material to detect a steep change in the plate thickness. At this time, the rolling position is corrected based on the characteristic information using the tracked plate thickness. Only when the variation of the thickness in the thickness variation section exceeds a reference value, the tracking of the thickness and the calculation of the rolling position correction amount based on the characteristic information are performed. You may do it.

The thickness control apparatus of the twin-drum continuous casting equipment according to the present invention is a thickness control apparatus for controlling the thickness by rolling a rolled material cast by the twin-drum continuous casting equipment by a rolling mill. And a sheet thickness measurement means installed on the entry side of the rolling mill, a sheet temperature measurement means installed on the entry side of the rolling mill, and a sheet thickness or the sheet measured by the sheet thickness measurement means. The sheet temperature measured by the temperature measuring means, the ratio of the plastic coefficient of the sheet thickness fluctuation part and the plastic coefficient of the steady part without the sheet thickness fluctuation and the sheet thickness or the target sheet thickness of the rolled material on the entrance side of the rolling mill Calculating means for calculating a rolling position correction amount of the rolling mill and controlling a rolling position of the rolling mill based on the deviation, or characteristic information indicating a relationship with the deviation from the sheet temperature or the target sheet temperature. It is characterized by the following.

In another aspect of the present invention, the calculating means includes:
Based on the characteristic information, determine the plastic coefficient ratio from the plate thickness measured by the plate thickness measuring means installed on the entrance side of the rolling mill, using the determined plastic coefficient ratio, the sheet thickness variation The rolling position correction amount of the rolling mill with respect to the part is calculated.

In another aspect of the present invention, the calculating means calculates the rolling-down position correction amount based on the characteristic information only when the thickness variation in the thickness variation section exceeds a reference value. It is characterized by the following.

A computer-readable recording medium according to the present invention is a computer-readable recording medium for causing a computer to execute a processing procedure of a sheet thickness control method in a twin-drum continuous casting facility according to any one of claims 1 to 4. A program or a program for causing a computer to function as each of the means according to any one of claims 5 to 7 is recorded.

According to the present invention configured as described above, the plastic coefficient ratio between the hot band portion and the stationary portion is determined from predetermined characteristic information based on the measured sheet thickness or sheet temperature.
In addition, since the plastic coefficient of the steady portion is separately obtained, the plastic coefficient of the hot band in which the plate thickness is steep and fluctuates minutely can be grasped from the plate temperature or the plate thickness.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram schematically showing a configuration of a plate thickness control device in a twin-drum continuous casting facility according to the present embodiment. A strip-shaped slab 2 sent out from a pair of cooling drums 1 is viewed from the left side of the drawing. It is transported in the direction of the thick arrow.

In FIG. 1, 3 is a pinch roll,
The belt-shaped slab 2 is conveyed by being rotated as shown by an arrow by a driving device (motor) (not shown). 4
Is a pulse generator, which generates a pulse each time the pinch roll 3 rotates by a predetermined amount. That is, the pulse generator 4 is connected to a motor (not shown) of the pinch roll 3, and sequentially generates pulses at intervals according to the rotation speed of the pinch roll 3, that is, the conveyance speed of the strip 2.

Reference numeral 5 denotes a thickness gauge disposed on the entrance side of the rolling mill 9, and reference numeral 6 denotes a sheet thermometer similarly disposed on the entrance side of the rolling mill 9. Reference numeral 7 denotes a tracking circuit which synchronizes the sheet thickness measured by the sheet thickness gauge 5 and the sheet temperature measured by the sheet thermometer 6 together with the movement of the strip-shaped slab 2 in synchronization with the pulse sequentially given from the pulse generator 4. Record. Since the thickness variation occurring on the hot band is steep and minute, this tracking needs to be performed with high accuracy. Therefore, tracking is performed with high accuracy by having a table in which the distance from the thickness gauge 5 to the rolling mill 9 is equally divided at certain intervals.

Reference numeral 8 denotes an arithmetic circuit, and the tracking circuit 7
Based on the supplied sheet thickness and sheet temperature tracking results, the plasticity coefficient of the strip slab 2 is compensated to determine the amount of correction of the rolling position of the rolling mill 9. The rolling mill 9 controls the roll-down position (roll gap) according to the roll-down position correction amount obtained by the arithmetic circuit 8 so that the delivery-side sheet thickness becomes the target value.

Next, in the arithmetic circuit 8, the correction amount of the rolling position of the roll in the rolling mill 9 is determined from the sheet thickness and the sheet temperature tracked by the tracking circuit 7 in consideration of the plastic coefficient of the strip-shaped slab 2. The method is described in detail below. In the present embodiment, since the purpose is to perform a gain adjustment specific to the hot band for the rolling mill 9, it is necessary to first obtain the plastic coefficient of the slab in the hot band portion of the strip-shaped slab 2. In the example described below, this is determined from the plate thickness.

[0025] The belt-like slab 2 of the hot band portion of the plastic coefficient in (plate thickness variable portion) Q _i, plastic coefficient in the steady part there is no thickness variation and Q _o. Here, assuming that the ratio of these plastic coefficients is α, the plastic coefficient ratio α can be expressed as α = Q _i / Q _o (1).

[0026] In the plate thickness variation is not constant regions, it is possible to measure the plate temperature regardless the responsiveness of the sheet temperature meter 6, is possible to obtain the plastic factor Q _o of the constant region from a sheet temperature which is the measured It is possible. For example, it is possible to use the method described in JP 62-45419 Publication mentioned as a conventional example, to determine the plastic factor Q _o in accordance with the sheet temperature of the constant region. Therefore, from the above equation (1), the plastic coefficient Q _i of the hot band can be determined if the value of the plastic coefficient ratio α is known.

The method of calculating the plasticity coefficient ratio α will be described below.
Assuming that the target value of the thickness at the exit side of the rolling mill 9 is h, the mill rigidity constant of the rolling mill 9 is M, and the rolling position (roll gap) of the rolling mill 9 is S, the stationary portion of the strip-shaped slab 2 is The rolling load P when rolling is represented by the following equation (2). P = M (h-S) (2) This expresses the rolling load P in consideration of the rigidity (hardness) of the mill of the rolling mill 9 itself.

Further, assuming that the target value of the sheet thickness at the entry side of the rolling mill 9 is H, the rolling load P when the above-mentioned steady portion is rolled is obtained.
It can be expressed in the following equation (3) using the constant part plastic factor Q _o of the slab. P = Q _o (Hh) (3) This expresses the rolling load P in consideration of the hardness of the strip 2. Therefore, the above equations (2) and (3)
Thus, the following equation (4) holds. M (h−S) = Q _o (H−h) (4)

On the other hand, assuming that the thickness deviation from the target value of the hot band portion on the entry side of the rolling mill 9 is ΔH and the amount of correction of the rolling position of the rolling mill 9 is ΔS, the hot band portion is
In P _H is the rolling load when the rolling, using the relationship of Equation (1), expressed as the following equation (5). P _H = M {h− (S−ΔS)} = αQ _o {(H + ΔH) −h} (5) When this equation (5) is solved for α, the following equation (6) is obtained.

[0030]

(Equation 1)

Further, when this equation (6) is transformed using the above equation (4), the following equation (7) is derived.

[0032]

(Equation 2)

Further, when the above equation (7) is solved for ΔS, the following equation (8) is obtained. As is apparent from this, the rolling position correction amount ΔS to be determined in the arithmetic circuit 8
Includes a stationary portion plastically factor Q _o obtained from a sheet temperature which is measured by the sheet temperature gauge 6, and the deviation ΔH of plate thickness at the entry side of the rolling mill 9 as measured by a thickness gauge 5 with respect to the target value H, plastic coefficient If the ratio α is known, it can be obtained.

In the above equation, the thickness deviation Δh on the exit side of the rolling mill 9 is omitted, but it is not always the case that Δh = 0 when obtaining the characteristic information described later. Therefore, regarding the plasticity coefficient ratio α in the above equation (8),
The relationship between the thickness deviation ΔH on the entry side and the plastic coefficient ratio α may be experimentally obtained in advance in consideration of the thickness deviation Δh on the exit side.

[0035]

(Equation 3)

FIG. 2 is a diagram schematically showing the relationship between the above equations (1) to (8). The X-axis indicates the thickness of the strip-shaped slab 2 at the entrance / exit side of the rolling mill 9. , The rolling position of the rolling mill 9 (roll gap), and the Y axis represents the rolling load applied to the rolling mill 9. In the steady portion where the thickness variation does not occur, the rolling load P applied to the rolling mill 9 is represented by the Y coordinate at the intersection of the two solid straight lines 10, 11 (corresponding to equations (2) and (3), respectively). expressed. By applying such a rolling load P to the strip-shaped slab 2, the thickness at the exit side of the rolling mill 9 is controlled to be the target value h.

[0037] In contrast, in the hot band is generated on the belt-like cast piece 2, with thickness deviation ΔH occurs in the entry side of the rolling mill 9, the plastic coefficient changes from Q _o to Q _i = αQ _o The straight line 11 shown above is a straight line 1 shown by a dotted line.
2 (corresponding to the last term of equation (5)). In addition,
Hot band portion, so compared to the steady portion plate are softened, it is a value small hot band portion plastically factor Q _i than the steady portion plastically factor Q _o, the slope of the straight line 12 is a straight line 1
It is smaller than that of 1.

In such a state, if the rolling position of the rolling mill 9 is not adjusted at all, the sheet thickness at the exit side of the rolling mill 9 becomes a value h + Δh indicated by the X coordinate at the intersection of the straight line 10 and the straight line 12. As a result, a deviation Δh is generated with respect to the delivery side thickness target value h. Then, the rolling circuit correction amount ΔS is calculated by the arithmetic circuit 8 based on the equation (8), and the rolling mill 9 is calculated.
Is adjusted as indicated by the dotted line 13 (corresponding to the second term of the equation (5)), so that the thickness of the exit side of the rolling mill 9 can be maintained at the target value h.

FIG. 3 shows the relationship between the thickness deviation ΔH on the entry side of the rolling mill 9 and the plastic coefficient ratio α. In FIG. 3, the horizontal axis represents the entry-side sheet thickness deviation ΔH, and the vertical axis represents the plastic coefficient ratio α. The graph shown in FIG. 3 measures the incoming side sheet thickness deviation ΔH generated when the strip-shaped slab 2 is actually passed through the rolling mill 9, the plastic coefficient ratio α at that time, and the outgoing side sheet thickness deviation Δh. It is obtained experimentally using the actual rolling results including the actual rolling results, and the results are plotted with a plurality of dots.

If characteristic information indicating the relationship between the entry side sheet thickness deviation ΔH and the plastic coefficient ratio α as shown in FIG. 3 is registered in advance, the plastic coefficient ratio α can be obtained from the entry side sheet thickness deviation ΔH. Thus the measurement, reduction position correction amount ΔS shown in the above formula (8), using the characteristic information, and the constant part plastic factor Q _o obtained from a sheet temperature which is measured by the sheet temperature gauge 6, the thickness gauge 5 Thickness deviation Δ on the entry side of rolling mill 9
H.

FIG. 4 is a flowchart showing a processing procedure of a thickness control method performed by using the thickness control apparatus according to the present embodiment shown in FIG. In FIG. 4, first, step S
In 1, the thickness of the strip 2 on the entry side of the rolling mill 9 is measured by a thickness gauge 5. Then, in step S2, it is determined whether or not the measured plate thickness exceeds a preset reference value.

Here, if the plate thickness does not exceed the reference value, it is considered that there is no hot band there, so the process proceeds to step S3, and the normal AGC (Auto Gain Co
ntrol) controls the rolling position of the rolling mill 9. That is, the arithmetic circuit 8 determines the plasticity coefficient of the strip slab 2 based on the sheet temperature given by the sheet thermometer 6 and calculates the gain of the automatic sheet thickness control in the rolling mill 9. At this time, even if the strip thickness of the strip-shaped slab 2 fluctuates, if it is not a hot band, the sheet temperature can be measured even with a sheet thermometer 6 having poor response, and ordinary AGC is sufficient. It is possible to correspond to.

On the other hand, if the thickness measured by the thickness gauge 5 exceeds the reference value, it is considered that there is a hot band there, and the process proceeds to step S4 and subsequent steps.
Perform AGC for hot band. That is, first, in step S4, tracking of the sheet thickness is started by the tracking circuit 7. Although FIG. 4 shows that the measurement of the plate thickness is performed in step S <b> 1, actually, this measurement is always performed, and the measured result is recorded by the tracking circuit 7.

Since the tracking is performed with high precision as described above, a steep and minute fluctuation in the thickness of the hot band can be reliably detected. Next step S
5, the arithmetic circuit 8 utilizes the characteristic information of the entrance side sheet thickness deviation ΔH and the plastic coefficient ratio α as shown in FIG.
The target value H of the incoming side plate thickness given by the tracking circuit 7
Is determined from the deviation ΔH with respect to.

Then, in step S6, the arithmetic circuit 8 calculates the rolling position correction amount ΔS based on the above equation (8) using the determined plastic coefficient ratio α, and in step S7 the rolling mill 9
To control the rolling position. Incidentally, the constant portion plastically factor Q _o in the equation (8) is determined from a sheet temperature which is measured by the sheet temperature meter 6. FIG. 5 is a diagram showing the result of implementing the above-described thickness control method.

In FIG. 5, the graph A shows the thickness deviation of the strip-shaped slab 2 on the entrance side of the rolling mill 9, and shows that a hot band is generated in a certain time zone. On the other hand, the graph B shows the thickness deviation of the strip-shaped slab 2 on the exit side of the rolling mill 9, and shows that a good exit side thickness deviation is obtained even in the hot band portion. .

As described in detail above, according to the present embodiment, the rolling mill 9 is used by utilizing the characteristics shown in FIG.
The plastic coefficient ratio α and the hot band plastic coefficient Q _i were estimated from the sheet thickness deviation ΔH on the entry side of, and the rolling position of the rolling mill 9 was corrected based on the estimated coefficient. High-precision sheet thickness control can be reliably performed even for steep sheet thickness fluctuations (hot bands) that occur during continuous casting in a continuous casting facility.

In this embodiment, as described in the flowchart of FIG. 4, the hot band AGC is performed only when the measured thickness exceeds a predetermined value. Unnecessary operations such as thickness tracking can be prevented from being performed in portions other than the possible hot bands.

The above-described sheet thickness control method in the twin-drum continuous casting facility of the present embodiment, in particular, the arithmetic processing in the arithmetic circuit 8 is performed by the CPU, MPU, RA, or the like.
It can be realized by operating a program stored in the RAM or ROM in a computer configured with M, ROM, and the like.

Therefore, according to the present invention, a program that causes a computer to perform the above functions is stored in, for example, C
This can be realized by recording the data on a recording medium such as a D-ROM and reading the data into a computer. As a recording medium for recording the program, a floppy disk, a hard disk, a magnetic tape, a magneto-optical disk, a nonvolatile memory card, or the like can be used in addition to the CD-ROM.

Further, the functions of the above-described embodiments are realized not only by the computer executing the supplied program, but also by the operating system (OS) or other application software running on the computer. When the functions of the above-described embodiment are realized in cooperation with the computer, or when all or a part of the processing of the supplied program is performed by a function expansion board or a function expansion unit of a computer, the functions of the above-described embodiment are realized. Such a program is also included in the embodiment of the present invention.

In the above-described embodiment, the AGC method of controlling the thickness is changed between the hot band portion and the non-hot band portion. However, the hot band AGC may be applied to all portions. Further, in the above embodiment, the characteristic information indicating the relationship between the entrance side sheet thickness deviation ΔH and the plastic coefficient ratio α as shown in FIG. 3 is used, but the relationship between the measured plate thickness itself and the plastic coefficient ratio α is used. It may be characteristic information to be represented.

Also, instead of estimating the plasticity coefficient of the hot band from the relationship between the thickness (deviation) and the plasticity coefficient ratio α,
It is also possible to estimate the plastic coefficient from the relationship between the sheet temperature (deviation) and the plastic coefficient ratio α.

[0054]

As described above, according to the present invention, the ratio of the plastic coefficient of the sheet thickness fluctuation portion and the plastic coefficient of the steady portion where there is no fluctuation in the sheet thickness, and the sheet thickness or the target sheet thickness of the rolled material on the entry side of the rolling mill. And the characteristic information representing the relationship between the deviation with respect to the sheet temperature or the deviation with respect to the target sheet temperature, and calculates the rolling position correction amount of the rolling mill based on the measured sheet thickness or sheet temperature and the characteristic information. Thus, the plastic coefficient of the hot band in which the plate thickness is steep and minutely fluctuates can be obtained from the plate thickness or the plate temperature, and the gain adjustment specific to the hot band can be performed. This makes it possible to reliably perform high-accuracy thickness control even for a hot band having a rapid and minute variation in thickness.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically illustrating a configuration of a sheet thickness control device in a twin-drum continuous casting facility according to an embodiment.

FIG. 2 is a diagram schematically illustrating a method of calculating a rolling position correction amount of a rolling mill.

FIG. 3 is a characteristic diagram showing a relationship between a thickness deviation of a slab at the entry side of a rolling mill and a plastic coefficient ratio.

FIG. 4 is a flowchart showing a processing procedure of a thickness control method performed using the thickness control apparatus according to the embodiment shown in FIG.

FIG. 5 is a diagram showing a result of executing a sheet thickness control method in a twin-drum continuous casting facility of the present embodiment.

FIG. 6 is a view showing a partial configuration of a twin-drum continuous casting facility.

FIG. 7 is a diagram for explaining a hot band.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 cooling drum 2 strip slab 3 pinch roll 4 pulse generator 5 entry side thickness gauge 6 entry side thermometer 7 tracking circuit 8 arithmetic circuit 9 rolling mill

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Takashi Oda 3434 Shimada, Hikari-shi, Nippon Steel Corporation Inside the Hikari Works (72) Inventor Shunji Shoda 3434 Shimada, Hikari-shi, Hikari-shi Nippon Steel Corporation Inside the Shako Works (72) Inventor Shuichi Inoue 3434 Shimada, Hikari-shi

Claims (9)

[Claims] 1. A thickness control method for rolling a rolled material cast by a twin-drum continuous casting facility by a rolling mill and controlling the thickness thereof, comprising: The ratio of the plastic coefficient of the steady part, and the deviation of the rolled material at the entry side of the rolling mill from the plate thickness or the target plate thickness, or having characteristic information representing the relationship between the deviation from the plate temperature or the target plate temperature, Based on the sheet thickness or sheet temperature measured by the sheet thickness measuring means or sheet temperature measuring means installed on the entrance side of the rolling mill and the characteristic information, the rolling position correction amount of the rolling mill is calculated and A method for controlling a thickness of a twin-drum continuous casting facility, comprising controlling a rolling position of a rolling mill. 2. The plastic coefficient ratio is determined from a sheet thickness or a sheet temperature measured by a sheet thickness measuring means or a sheet temperature measuring means installed on the entrance side of the rolling mill based on the characteristic information. 2. A thickness control in a twin-drum continuous casting facility according to claim 1, wherein a correction amount of a rolling position of the rolling mill with respect to the thickness variation portion is calculated using the determined plastic coefficient ratio. Method. 3. The method according to claim 1, wherein the calculation of the rolling position correction amount based on the characteristic information is performed only when the variation of the thickness in the thickness variation portion exceeds a reference value. A method for controlling a thickness of a twin-drum continuous casting facility according to the above. 4. A steep thickness variation is detected by tracking the thickness measured by the thickness measuring means together with the movement of the rolled material, and the thickness is tracked based on the characteristic information. The calculation of the rolling position correction amount is performed, and the calculation of the rolling position correction amount based on the tracking of the thickness and the characteristic information is performed only when the variation of the thickness in the thickness variation section exceeds a reference value. 3. The method for controlling a thickness of a twin-drum continuous casting facility according to claim 1, wherein the thickness is controlled. 5. A thickness control device for rolling a rolled material cast by a twin-drum continuous casting facility by a rolling mill and controlling the thickness thereof, wherein the thickness is set on an entrance side of the rolling mill. Measuring means, a sheet temperature measuring means installed on the entry side of the rolling mill, a sheet thickness measured by the sheet thickness measuring means or a sheet temperature measured by the sheet temperature measuring means, and a sheet thickness varying portion Represents the relationship between the plastic coefficient and the ratio of the plastic coefficient of the steady part where there is no variation in sheet thickness to the deviation of the rolled material at the entry side of the rolling mill from the sheet thickness or the target sheet thickness, or the sheet temperature or the deviation from the target sheet temperature. A thickness control device for a twin-drum continuous casting facility, comprising: calculating means for calculating a rolling reduction position of the rolling mill based on the characteristic information and controlling a rolling position of the rolling mill. . 6. The calculating means determines the plasticity coefficient ratio from the thickness measured by the thickness measuring means installed on the entrance side of the rolling mill based on the characteristic information, and determines the determined plasticity. The thickness control apparatus for a twin-drum continuous casting facility according to claim 5, wherein a correction amount of a rolling position of the rolling mill with respect to the thickness variation portion is calculated using a coefficient ratio. 7. The method according to claim 1, wherein the calculating means calculates the roll-down position correction amount based on the characteristic information only when the thickness variation in the thickness variation portion exceeds a reference value. Item 7. A thickness control apparatus for a twin-drum continuous casting facility according to item 5 or 6. 8. A computer-readable program for recording a program for causing a computer to execute a processing procedure of a method for controlling a thickness of a twin-drum continuous casting facility according to claim 1. Description: Possible recording medium. 9. A computer-readable recording medium on which a program for causing a computer to function as each of the means according to claim 5 is recorded.