JPWO2015029171A1 - Thickness control device for rolling mill - Google Patents

Abstract

A sheet thickness control device for a rolling mill capable of accurately identifying the plasticity coefficient of a rolled material is provided. For this reason, the sheet thickness control device of the rolling mill identifies the plastic coefficient that represents the hardness of the rolled material based on the actual rolling load value, the actual roll gap value, and the mill constant of the rolling stand to be operated. Device. In the said structure, the plasticity coefficient of a rolling material is identified based on the data obtained with the rolling stand of operation object. For this reason, the plasticity coefficient of a rolling material can be identified correctly.

Description

  The present invention relates to a sheet thickness control device for a rolling mill.

  Patent Document 1 describes a plate thickness control device for a rolling mill. The sheet thickness control device identifies the plastic coefficient of the rolling stand based on information on the thickness of the rolled material measured on the upstream side of the rolling stand, information on the rolling load of the rolling stand on the upstream side of the rolling stand, etc. To do. The said plate | board thickness control apparatus performs plate | board thickness control of the rolling material by the said rolling stand based on the identified plasticity coefficient.

Japanese Unexamined Patent Publication No. 2008-126307

  However, the one described in Patent Document 1 identifies the plastic coefficient of the rolling stand by tracking information on the rolling stand upstream of the rolling stand to the downstream side. For this reason, the plasticity coefficient of a rolling material cannot be identified correctly.

  The present invention has been made to solve the above-described problems. An object of the present invention is to provide a plate thickness control device for a rolling mill that can accurately identify the plasticity coefficient of a rolled material.

  A sheet thickness control device for a rolling mill according to the present invention is a plastic coefficient that identifies a plastic coefficient representing the hardness of a rolled material, based on a rolling load actual value, a roll gap actual value, and a mill constant of a rolling stand to be operated. An identification device.

  According to this invention, the plasticity coefficient of the rolled material can be accurately identified.

It is a block diagram of the rolling mill using the plate | board thickness control apparatus of the rolling mill in Embodiment 1 of this invention. It is a control block diagram of the rolling mill using the plate thickness control apparatus of the rolling mill in Embodiment 1 of this invention. It is a figure for demonstrating the influence of the mill constant and plasticity coefficient at the time of rolling a rolling material with the rolling mill using the plate | board thickness control apparatus of the rolling mill in Embodiment 1 of this invention. It is a figure for demonstrating the influence of the mill constant and plasticity coefficient at the time of rolling a rolling material with the rolling mill using the plate | board thickness control apparatus of the rolling mill in Embodiment 1 of this invention. It is a block diagram of the principal part of the plate | board thickness control apparatus of the rolling mill in Embodiment 1 of this invention. It is a principal part of the control block diagram of a rolling mill using the plate | board thickness control apparatus of the rolling mill in Embodiment 1 of this invention. It is a figure for demonstrating the table of the plasticity coefficient which the plasticity coefficient identification apparatus of the plate | board thickness control apparatus of the rolling mill in Embodiment 1 of this invention has. It is a figure for demonstrating the estimation result of the roll eccentric disturbance by the plate | board thickness control apparatus of the rolling mill in Embodiment 1 of this invention. It is a figure for demonstrating the estimation result of the rolling load disturbance by the plate | board thickness control apparatus of the rolling mill in Embodiment 1 of this invention. It is a principal part of the control block diagram of the plate | board thickness control apparatus of the rolling mill in Embodiment 2 of this invention.

  A mode for carrying out the invention will be described with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the part which is the same or it corresponds in each figure. The overlapping explanation of the part is appropriately simplified or omitted.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram of a rolling mill using a rolling mill thickness control apparatus according to Embodiment 1 of the present invention.

  In FIG. 1, the rolling stand for hot sheet rolling is a 4Hi mill. The rolling stand includes a housing 1. In the housing 1, an upper work roll 2a and a lower work roll 2b are provided as rolling rolls. One side of the shaft of the upper work roll 2a is connected to an electric motor (not shown). A work area is secured around the other side of the upper work roll 2a. One side of the shaft of the lower work roll 2b is connected to an electric motor (not shown). A work area is secured around the other side of the lower work roll 2b.

  Above the upper work roll 2a, an upper backup roll 3a is provided as a rolling roll. The upper backup roll 3a supports the upper work roll 2a. The upper backup roll 3 a is supported on the upper part of the housing 1. One side of the shaft of the upper backup roll 3a is connected to an electric motor (not shown). A work area is secured around the other side of the upper backup roll 3a.

  A lower backup roll 3b is provided as a rolling roll below the lower work roll 2b. The lower backup roll 3b supports the lower work roll 2b. The lower backup roll 3 b is supported at the lower part of the housing 1. One side of the shaft of the lower backup roll 3b is connected to an electric motor (not shown). A work area is secured around the other side of the lower backup roll 3b.

  A reduction device 4 is provided above the upper backup roll 3a. For example, the reduction device 4 is an electric reduction device. For example, the reduction device 4 is a hydraulic reduction device that is driven by hydraulic pressure. The hydraulic reduction device can be controlled at high speed. The reduction device 4 includes a drive side reduction device 4a and an operation side reduction device 4b. The drive side reduction device 4a is provided on one side of the upper backup roll 3a. The operation side reduction device 4b is provided on the other side of the upper backup roll 3a.

  A load detector 5 is provided below the lower backup roll 3b. The load detector 5 includes a drive side load detector 5a and an operation side load detector 5b. The drive side load detector 5a is provided on one side of the lower backup roll 3b. The operation side load detector 5b is provided on the other side of the upper backup roll 3a.

  A roll gap detector 6 is provided below the reduction device 4. The roll gap detector 6 includes a drive side roll gap detector 6a and an operation side roll gap detector 6b. The drive-side roll gap detector 6a is provided on one side of the upper backup roll 3a. The operation side roll gap detector 6b is provided on the other side of the upper backup roll 3a.

  The input side of the rolling load measuring device 7 is connected to the output side of the load detector 5. The input side of the roll gap measuring device 8 is connected to the output side of the roll gap detector 6.

  The input side of the plate thickness controller 9 is connected to the output side of the rolling load measuring device 7. The input side of the plate thickness controller 9 is connected to the output side of the roll gap measuring device 8. The input side of the roll gap operating means 10 is connected to the output side of the plate thickness controller 9. The output side of the roll gap operating means 10 is connected to the input side of the reduction device 4.

  The lower work roll 2b is provided with a roll rotation number detector 11. A thickness gauge 12 is provided on the exit side of the rolling stand.

  The rolled material 13 is made of metal. The rolled material 13 is sandwiched between the upper work roll 2a and the lower work roll 2b. As a result, the rolled material 13 extends. At this time, the upper backup roll 3a suppresses the deflection in the width direction of the upper work roll 2a. The lower backup roll 3b suppresses the deflection in the width direction of the lower work roll 2b. The rolling load on the rolled material 13 is received by the housing 1 through the upper work roll 2a, the lower work roll 2b, the upper backup roll 3a, and the lower backup roll 3b.

  The drive side load detector 5a detects the load applied to one side of the lower backup roll 3b. The operation side load detector 5b detects a load applied to the other side of the lower backup roll 3b. The rolling load measuring device 7 calculates the sum of the detection value of the drive side load detector 5a and the detection value of the operation side load detector 5b as a sum load. The rolling load measuring device 7 calculates the difference between the detection value of the drive side load detector 5a and the detection value of the operation side load detector 5b as a differential load. When a roll bending apparatus (not shown) is provided in the rolling stand, the rolling load measuring device 7 performs calculation when correcting the detection value of the load detector 5 with the roll bending force.

  The roll gap detector 6 does not directly detect a gap (roll gap) between the upper work roll 2a and the lower work roll 2b. The roll gap detector 6 detects the amount by which the reduction device 4 pushes down the upper backup roll 3a. The roll gap measuring device 8 calculates the roll gap based on the detection value of the roll gap detector 6. At this time, the roll gap measuring device 8 considers the distance relationship between the upper work roll 2a and the lower work roll 2b.

The plate thickness controller 9 adjusts the set value of the roll gap based on the calculated value of the rolling load measuring device 7 and the calculated value of the roll gap measuring device 8. In this case, the plate thickness controller 9 adjusts the setting value of the roll gap with the mill constant M _C identified by a not-shown identification apparatus in FIG. _1, a plastic coefficient Q _C.

  The roll gap operating means 10 adjusts the roll gap based on the set value adjusted by the plate thickness controller 9. As a result, the rolled material 13 has a desired plate thickness. The plate thickness of the rolled material 13 is measured by a plate thickness meter 12.

  At this time, the roll rotation number detector 11 detects the rotation number of the lower work roll 2b. The roll rotation number detector 11 detects the rotation position of the lower work roll 2b. By the detection, the circumferential position of the lower work roll 2b is specified. Specifically, the position of the reference point on the circumference is specified when the lower work roll 2b is regarded as a circle when viewed from the side. For example, the rotation angle of the reference point with respect to the vertical line is specified.

Next, an example of the plate thickness controller 9 will be described with reference to FIG.
FIG. 2 is a control block diagram of a rolling mill using the rolling mill thickness control apparatus according to Embodiment 1 of the present invention.

  In FIG. 2, the rolling process 14 to be controlled is affected by the mill constant M and the plasticity factor Q. Specifically, the rolling process 14 includes a first influence coefficient 14a and a second influence coefficient 14b. The first influence coefficient 14a corresponds to the influence of the roll gap on the rolling load. The first influence coefficient 14a is -MQ / (M + Q). The second influence coefficient 14b corresponds to the influence of the rolling load on the plate thickness. The second influence coefficient 14b is 1 / M.

The rolling process 14, applied with roll eccentricity disturbance [Delta] S _D and the rolling load disturbance [Delta] P _D is. The roll eccentricity disturbance [Delta] S _D and the rolling load disturbance [Delta] P _D can not be measured directly.

  The plate thickness controller 9 implements a monitor AGC 15, a gauge meter AGC 16, an MMC (mill constant variable control) 17, etc. for the rolling process 14.

The first control block 18 calculates the plate thickness measurement value change amount Δh ^MES based on the plate thickness actual change amount Δh ^ACT measured by the plate thickness meter 12. At this time, the first control block 18 considers the conveyance delay time of the rolled material 13 from the rolling stand to the plate thickness gauge 12.

The monitor AGC 15 calculates the GM plate thickness target value change amount Δh ^REF based on the deviation between the product plate thickness target value change amount Δhx ^REF and the plate thickness measured value change amount Δh ^MES .

In the gauge meter AGC 16, the second control block 16a is represented using mill modulus _{M C} identified. The second control block 16a, the coefficient alpha ₁ for adjusting the response is added. Based on the output of the second control block 16a and the roll gap actual change amount ΔS ^ACT , the GM plate thickness change amount Δh _GM is obtained.

In the gauge meter AGC16, the gauge meter plate thickness target value change amount Δh _GM ^AIM and the GM plate thickness target value change amount Δh ^REF are added together. As a result, the plate thickness target value change amount Δh _GM ^REF is obtained. The deviation between the plate thickness target value change amount Δh _GM ^REF and the GM plate thickness change amount Δh _GM is input to the PI controller 16b. The PI controller 16b is represented by a proportional gain _KPG , an integral gain _KIG, and a Laplace operator S. It is assumed that the roll gap symbol S is accompanied by a subscript or Δ, and the Laplace operator S is used alone.

The output of the PI controller 16b is input to the compensation gain 16c. The compensation gain 16c is represented by the identified mill constant M _C , plastic coefficient Q _C , and coefficients α ₁ and α ₂ for adjusting the response. The compensation gain 16c calculates a roll gap command value ΔS ^SET . At this time, the compensation gain 16c normalizes the operation output. In this case, adjustment of the PI controller 16b is not necessary even if the mill constant M, plastic coefficient Q, and coefficients α ₁ and α _{2 to} be controlled change.

  The MMC 17 requests the reduction device 4 for a high-speed response. For this reason, when the reduction device 4 is not a hydraulic reduction device, the MMC 17 is not applied.

In MMC17, third control block 17a is represented using mill modulus _{M C} identified. MMC17 by adjusting the coefficient alpha ₂ of the third control block 17a, may adjust the response. For example, by increasing the coefficient alpha _2, the response becomes faster.

  In the MMC 17, the hydraulic pressure reduction response 17b corresponds to the response of the hydraulic pressure reduction device. The hydraulic pressure reduction response 17b is determined based on a value obtained by superimposing the output of the compensation gain 16c and the output of the third control block 17a. As a result, the roll gap is adjusted.

Next, the influence of the mill constant M and the plasticity coefficient Q on the thickness of the rolled material 13 will be described with reference to FIG.
FIG. 3 is a diagram for explaining the influence of the mill constant and the plastic coefficient when rolling a rolled material by a rolling mill using the thickness control device of the rolling mill according to Embodiment 1 of the present invention.

  In FIG. 3, the mill curve represents the state of mill elongation. Mill elongation occurs when the housing 1 or the like receives a large rolling load from the rolled material 13. The mill elongation increases as the rolling load increases. The mill curve is approximated by a quadratic curve or a cubic curve. The mill curve can be measured.

  Mill constant M represents the ratio of mill elongation. The mill constant M is represented by the slope of the mill curve at the specified rolling load. For example, when the rolling load is 600 (kN) and the mill elongation is 1 (mm), the mill constant M is 600 (kN / mm).

  In FIG. 3, the plastic curve is obtained by plotting the change in rolling load when the plate thickness of the rolled material 13 changes. When the strength of the rolled material 13 is high, a plastic curve is established. When the temperature of the rolling material 13 is low, a plastic curve is established. Plastic curves cannot be measured directly.

  The plasticity coefficient Q represents the hardness of the rolled material 13. The plastic coefficient Q is represented by the slope of the plastic curve at a specified rolling load.

In FIG. 3, the initial state is represented by an intersection (a) between the mill curve and the plastic curve. In this case, the roll gap is _{S G.} The thickness of the rolling material 13 on the entry side of the rolling stand is H. The thickness of the rolled material 13 on the exit side of the rolling stand is h.

When the temperature of the rolled material 13 decreases, a plastic curve is established. The state at this time is represented by an intersection (b) between the mill curve and the plastic curve. As a result, the sheet thickness of the rolled material 13 on the exit side increases to h + Δh. When the roll gap is changed from S _G to S _G -ΔS _G by the plate thickness control, the mill curve moves to the left. The state at this time is represented by an intersection (c) between the mill curve and the plastic curve. As a result, the thickness of the rolled material 13 on the exit side is thinner than h + Δh.

Next, details of the influence of the mill constant M and the plasticity coefficient Q will be described with reference to FIG.
FIG. 4 is a diagram for explaining the influence of the mill constant and the plastic coefficient when the rolled material 13 is rolled by a rolling mill using the thickness control device of the rolling mill according to Embodiment 1 of the present invention.

In FIG. 4, the mill constant M is expressed by the following equation (1).

  Considering the relational expression formed by the triangle of FIG. 4, tan α is expressed by the following expression (2).

  From the formulas (1) and (2), a gauge meter formula is obtained. The gauge meter equation is expressed by the following equation (3).

  In FIG. 4, the plastic coefficient Q is expressed by the following equation (4).

  Considering the relational expression formed by the triangles in FIG. 4, the plastic coefficient Q is expressed by the following expression (5).

  From the equations (4) and (5), the relationship between the plastic coefficient Q and the sheet thickness H of the entry-side rolled material 13 is obtained. The relationship between the plastic coefficient Q and the plate thickness H of the rolled material 13 on the entry side is expressed by the following equation (6).

4, when opening the roll gap by [Delta] S _G, the state moves from point (A) to point (B). At this time, the mill constant M is expressed by the following equation (7).

  From the equation (7), the rolling load change ΔP is expressed by the following equation (8).

  The plasticity coefficient Q is expressed by the following equation (9).

  From the equation (9), the rolling load variation ΔP is expressed by the following equation (10).

  From the equations (8) and (10), the change amount Δh of the thickness of the rolled material 13 is expressed by the following equation (11).

  From the equations (10) and (11), the rolling load variation ΔP is expressed by the following equation (12).

  From the equation (3), the thickness variation Δh is expressed by the following equation (13).

Next, the identification device will be described with reference to FIG.
FIG. 5 is a block diagram of the main part of the sheet thickness control apparatus for a rolling mill according to Embodiment 1 of the present invention.

  As shown in FIG. 5, the identification device includes a mill constant identification device 19 and a plastic coefficient identification device 20.

The mill constant identification device 19 calculates the mill constant M ^ID based on the rolling load actual change ΔP ^ACT , the roll gap actual change ΔS ^ACT , the sheet thickness actual change Δh ^ACT , and the roll rotation angle actual value φ ₁ . The mill constant M ^ID is input to the mill constant Mc of the gauge meters AGC16 and MMC17. At this time, the mill constant Mc may be a mill constant ^MMES identified by another method by a kiss roll test or the like.

The plastic coefficient identification device 20 calculates the plastic coefficient Q ^ID based on the rolling load actual change amount ΔP ^ACT , the roll gap actual change amount ΔS ^ACT , the roll rotation angle actual value φ ₂ , and the identified mill constant. At this time, the identified mill constant is selected from the mill constant M ^ID or the mill constant M ^MES . Plastic factor ^{Q ID} is input to the plastic coefficient _{Q C} of the gauge meter AGC 16.

Next, a method for calculating the mill constant M ^ID and the plasticity coefficient Q ^ID will be described with reference to FIG.
FIG. 6 is a main part of a control block diagram of a rolling mill using the rolling mill thickness control apparatus according to Embodiment 1 of the present invention.

In FIG. 6, noise _Nh is added to the rolling process 14 of FIG. 2, and the actual plate thickness variation Δh ^ACT is observed.

In FIG. 6, the amount of change Δh in the thickness of the rolled material is expressed by the following equation (14) using the error e ₁ due to the noise N _h .

Roll eccentricity disturbance [Delta] S _D is the structure of the rolling rolls, caused by inaccuracies such polishing of the rolling rolls. For example, in a support roll having an oil bearing, when the keyway receives a rolling load of several hundred tons to several thousand tons, the shaft moves up and down. By the movement, the roll eccentricity disturbance [Delta] S _D will occur. For example, in the rolling roll without keyway, the deviation or the like of the thermal expansion, roll eccentricity disturbance [Delta] S _D will occur.

Roll eccentricity disturbance [Delta] S _D may be considered periodic disturbance synchronizing rotation period of the upper backup roll 3a and a lower backup roll 3b. During rolling, the rolling speed changes. Therefore, the period of roll eccentricity disturbance [Delta] S _D varies with time. Roll eccentricity disturbance [Delta] S _D is changed at a constant period upper work roll 2a, the lower work roll 2b, the upper backup roll 3a, with respect to the rotation angle phi ₁ of the lower backup roll 3b (0 to 360 degrees).

In this case, the roll eccentricity disturbance [Delta] S _D is approximated by k-th order Fourier series. Specifically, the roll eccentricity disturbance [Delta] S _D is expressed by the following equation (15).

  When the equation (14) is modified and the equation (15) is used, the following equation (16) is obtained.

  The expression (16) is an expression representing the relationship between the respective variables at a certain time of the rolled material 13, and generally a plurality of data sets are obtained from the rolled material 13, and each data set satisfies the expression (16). . By estimating the most probable parameters satisfying the plurality of equations (16), parameters such as the mill constant M can be obtained.

For example, when N data sets are obtained for one rolled material 13, the rolling load actual change amount ΔP ^ACT , the roll gap actual change amount ΔS ^ACT , the plate thickness measured value change amount Δh ^ACT , and the roll rotation angle. actual phi ₁ is obtained the N, respectively.

  When N pieces of data are applied to the equation (16), N simultaneous equations are obtained. In order to express them collectively, variables represented by vectors and matrices are defined below.

A data set of Δh−ΔS is a column vector Y ₁ including N Δh ^ACT −ΔS ^ACT elements. The data set [ΔP I cos φ ₁ sin φ ₁ ... Cos (kφ ₁ ) sin (kφ ₁ )] is a column vector including N ΔP ^ACT elements, and an N-row 1-column matrix including only one element. Let I _{NX1 be} a matrix X ₁ of N rows and 2k columns containing sin and cos values of N φ ₁ . [1 / M a _S0 a _S1 b _S1 ... A _Sk b _Sk ] ^T appearing in the first term on the right side of the equation (16) is defined as a column vector θ ₁ .

When these are put together, the following equation (17) is obtained. Here, a data set of error e ₁ due to noise is represented by a vector E ₁ .

In order to solve equation (17), an optimization method is used. Several optimization methods have been proposed. Here, an example of identification by the most general least square method is shown.
The least square solution of θ ₁ is expressed by the following equation (18).

The mill constant identification device 19 calculates the mill constant M ^ID using the equation (18). At this time, the mill constant identification device 19 compensates for the delay time due to the conveyance between the rolling stand and the plate thickness meter 12 with respect to the plate thickness actual value change amount Δh ^ACT . With this compensation, the sheet thickness actual value variation Δh ^ACT is synchronized with the rolling load actual variation ΔP ^ACT and the roll gap actual variation ΔS ^ACT .

The mill constant M greatly depends on the mechanical characteristics of the housing 1, the upper work roll 2a, the lower work roll 2b, the upper backup roll 3a, and the lower backup roll 3b. For this reason, the mill constant M ^ID is calculated for each rolling stand.

  For example, it is assumed that rolling stand data is accumulated and the mill constant is identified as M [1] (stored) (kN / mm). It is assumed that the same rolling stand data is obtained and the mill constant is identified as M [1] (raw) (kN / mm). In this case, the mill constant identification device 19 stores M [1] (raw). In the plate thickness control, a new smoothed mill constant is used. By smoothing, instability of the identification result due to data variation is suppressed. The new mill constant is expressed by the following equation (19).

  In the equation (19), a is a smoothing gain. a is set to a value from 0 to 1. When a is increased, the mill constant M [1] (raw) is easily reflected in the new mill constant.

  In the first rolled material 13 immediately after the upper work roll 2a, the lower work roll 2b or the upper backup roll 3a, and the lower backup roll 3b are replaced, the mill constant may be slightly different from the mill constant before the replacement. For this reason, immediately after replacement, the mill constant identification device 19 increases the ratio of M [1] (raw). In this case, the new mill constant is expressed by the following equation (20) using a smoothing gain A larger than a.

  Even if the upper work roll 2a, the lower work roll 2b or the upper backup roll 3a, the lower backup roll 3b are immediately replaced, several rolled materials 13 are rolled and A is continuously used until the data is stabilized. Good. In this case, the identification result after replacement of the upper work roll 2a, the lower work roll 2b or the upper backup roll 3a, the lower backup roll 3b is easily reflected.

  Next, a method for identifying the plasticity coefficient Q will be described below. The basic idea is the same as the mill constant M shown above.

In FIG. 6, the rolling load change ΔP is expressed by the following equation (21) using the error e ₂ due to the noise N _h .

  When the equation (21) is transformed, the following equation (22) is obtained.

At this time, w is defined by the following equation (23).

  When the rolled material 13 is a slab in a state before being rolled, the slab is arranged in a heating path (not shown). The heating furnace is provided with a plurality of skids (not shown). The plurality of skids are arranged at substantially equal intervals. The plurality of skids support the slab. The interior of the plurality of skids is cooled with water. For this reason, the temperature of the part which touches a skid falls in a slab. This part is called a skid mark.

Rolling load disturbance [Delta] P _D may be considered synchronous with periodic disturbance to skid marks. During rolling, the rolling speed changes. Therefore, the period of the rolling load disturbance [Delta] P _D varies with time. The rolling load disturbance ΔP _D changes at a constant cycle with respect to the rotation angle φ ₂ (0 degree to 360 degrees) of the upper work roll 2a, the lower work roll 2b, the upper backup roll 3a, and the lower backup roll 3b.

  In this case, w is approximated by a k-th order Fourier series. Specifically, w is expressed by the following equation (24).

  When the equation (22) is modified and the equations (23) and (24) are used, the following equation (25) is obtained.

  When N pieces of data obtained from the rolled material 13 are applied to the equation (25), N simultaneous equations are obtained. In order to express them collectively, variables represented by vectors and matrices are defined below.

The data set of ΔP is a column vector Y ₂ including elements of ΔP ^ACT . The data set [ΔS I cos φ ₂ sin φ ₂ ... Cos (kφ ₂ ) sin (kφ ₂ )] is a column vector including N ΔS ^ACT elements, and an N-row 1-column matrix including only one element. Let I _{NX1 be} an N × 2k matrix X ₂ containing sin and cos values of N φ ₂ . (25) the right-hand side appearing in paragraph of formula _{[-MQ / (M + Q)} a w0 a w1 b w1 ··· a wk b wk] is referred to as column vectors theta ₂ ^T.

When these are put together, the following equation (26) is obtained. Here, a data set of error e ₂ due to noise is represented by a vector E ₂ .

Similarly to equation (17), equation (26) is solved by the least square method. The least square solution of θ ₂ is expressed by the following equation (27).

The plastic coefficient identification device 20 calculates the plastic coefficient Q ^ID using equation (27). At this time, the mill constant M is selected from the mill constant M ^ID or the mill constant M ^MES .

  The plastic coefficient Q is identified at a timing when a certain number of data is accumulated. The plastic coefficient identification device 20 has a table of plastic coefficients using the rolling stand number, the steel type, the sheet thickness classification, and the temperature range as classification indices. Each cell in the table is called a lot. The following information (A) to (D) is associated with each lot.

(A) Number of rolled material 13 corresponding to the cell (B) ID number and rolling date and time of each rolled material 13 (C) Data necessary for identification of plastic coefficient obtained from each material (D) Roll previously identified ID number of material 13

The plastic coefficient identification device 20 calculates the plastic coefficient Q ^ID at the following timing (a) or timing (b) using the information (A) to (D).

(A) The plasticity coefficient Q ^ID is calculated when a certain number or more of new data is accumulated.
(B) Each time the data of the rolled material 13 included in the lot is collected, the plastic coefficient Q ^ID is calculated for the data of the lot.

In the case of timing (a), the engineer may make an appropriate determination by looking at the number of accumulated data. If the number of data exceeds a certain number, the plasticity coefficient Q ^ID may be automatically calculated.

  In the case of timing (b), data is accumulated in a certain lot (rolling stand, steel type, sheet thickness classification, temperature range), and the plasticity coefficient is Q [1, 2, 3, 4] (stored) (kN / mm ). It is assumed that data of the rolled material 13 having the same conditions as the lot is obtained and the plasticity coefficient is identified as Q [1, 2, 3, 4] (raw) (kN / mm). The plastic coefficient identification device 20 stores the new smoothed plastic coefficient in the lot. In the plate thickness control, a new smoothed plasticity coefficient is used. By smoothing, instability of the identification result due to data variation is suppressed. The new plasticity coefficient is expressed by the following equation (27).

  In the equation (28), b is a smoothing gain. b is set to a value from 0 to 1. When b is increased, the plastic coefficient Q [1, 2, 3, 4] (raw) is easily reflected in the new mill constant.

  Smoothing can also be applied in the case of timing (a). Smoothing different from the equation (28) may be applied.

Next, a table of the plasticity coefficient Q will be described with reference to FIG.
FIG. 7 is a diagram for explaining a table of plastic coefficients possessed by the plastic coefficient identification device of the sheet thickness control device of the rolling mill according to Embodiment 1 of the present invention.

  In FIG. 7, if a rolling stand, a steel type, a plate thickness classification, and a temperature range are designated, only one lot is designated. As a result, the lot is distinguished from other lots.

Next, the effectiveness of the mill constant M ^ID and the plasticity coefficient Q ^ID will be described with reference to FIGS.
FIG. 8 is a diagram for explaining an estimation result of roll eccentric disturbance by the sheet thickness control device of the rolling mill in Embodiment 1 of the present invention. FIG. 9 is a diagram for explaining an estimation result of the rolling load disturbance by the thickness control device of the rolling mill according to Embodiment 1 of the present invention.

As shown in FIG. 8, the estimated value of the roll eccentric disturbance substantially coincides with the actual disturbance value. As shown in FIG. 9, the estimated value of the rolling load disturbance substantially coincides with the actual disturbance value. For this reason, the mill constant M ^ID and the plasticity coefficient Q ^ID are accurately calculated.

  According to the first embodiment described above, the plastic coefficient identification device 20 identifies the plastic coefficient of the rolled material 13 based on the actual rolling load value, the actual roll gap value, and the mill constant of the rolling stand to be operated. . For this reason, the plasticity coefficient of the rolling material 13 can be identified accurately.

  Further, the mill constant identification device 19 identifies the mill constant of the rolling stand based on the rolling load actual value, the roll gap actual value, and the thickness of the rolled material on the downstream side of the rolling stand. To do. For this reason, the mill constant of the rolling stand can be accurately identified.

  The mill constant identification device 19 identifies the mill constant of the rolling stand based on the rotational position of the rolling roll of the rolling stand. Specifically, the mill constant identification device 19 calculates the mill constant using equation (18). For this reason, the mill constant of the rolling stand can be identified more accurately.

  The mill constant identification device 19 identifies the mill constant every time data of one rolled material 13 is obtained for the rolling stand, and smoothes it with the mill constant identified in the past. When the rolling rolls of the rolling stand are replaced, the mill constant identification device 19 makes the ratio using the latest identification data higher than usual. For this reason, the mill constant of the rolling stand can be identified more accurately.

  Moreover, the plastic coefficient identification device 20 identifies the plastic coefficient of the rolled material 13 based on the mill constant obtained by the kiss roll test. For this reason, the plasticity coefficient of the rolling material 13 can be identified more accurately.

  Moreover, the plastic coefficient identification device 20 identifies the plastic coefficient of the rolled material 13 based on the rotational position of the rolling roll of the rolling stand. Specifically, the plastic coefficient identification device 20 calculates the plastic coefficient using equation (26). For this reason, the plasticity coefficient of the rolling material 13 can be identified more accurately.

  Moreover, the plastic coefficient identification device 20 identifies the plastic coefficient of the rolled material 13 using data collected in advance. For this reason, the plasticity coefficient of the rolling material 13 is computable using the past data.

  The plastic coefficient identification device 20 identifies the plastic coefficient of the rolled material 13 when data is accumulated in a preset number for each lot divided by the same or similar steel type, sheet thickness, and rolling temperature range. . For this reason, the plasticity coefficient of the rolling material 13 can be calculated more accurately.

  Further, the plastic coefficient identification device 20 identifies the plastic coefficient of the rolled material 13 every time data is accumulated in lots divided by the same or similar steel type, sheet thickness, and rolling temperature range. For this reason, the plasticity coefficient of the rolling material 13 can be corrected with the latest data.

  When the thickness gauge 12 is not provided on the downstream side of the rolling stand, the thickness of the rolled material 13 on the exit side of the rolling stand may be obtained using a constant mass flow rule. The mass flow constant law is expressed by the following equation (29).

In the equation (29), the subscript X corresponds to the position immediately below the thickness gauge 12 when it is assumed that the thickness gauge 12 is provided. The subscript i corresponds to the rolling stand number. h is the thickness of the rolled material 13. V is the speed of the rolled material 13. f is the advanced rate. The advanced rate f is calculated from the rolling model. V _Ri is measured from the peripheral speed of the rolling roll of the rolling stand.

Embodiment 2. FIG.
FIG. 10 is a main part of a control block diagram of a sheet thickness control device for a rolling mill according to Embodiment 2 of the present invention. In addition, the same code | symbol is attached | subjected to Embodiment 1 and an equivalent part, and description is abbreviate | omitted.

Thickness controller 9 of the second embodiment, to improve the control performance by using a roll eccentricity disturbance [Delta] S _D identified. Specifically, the roll gap operating means 10, the roll eccentricity disturbance [Delta] S _D identified adjusting the roll gap in the opposite direction. By this adjustment, the roll eccentric disturbance is canceled out.

Actually, there is an error in specifying the position of the rolling roll, or the response of the hydraulic reduction device is delayed. For this reason, when the roll eccentric disturbance is compensated 100%, problems such as control hunting may occur. For this reason, an adjustment gain _KSD is introduced.

In Figure 10, to the estimated roll eccentricity disturbance [Delta] S _D, it is multiplied by the adjustment gain _{K SD,} roll eccentricity compensation amount [Delta] S _D ^REF is calculated. The roll eccentricity compensation amount ΔS _D ^REF is added to the roll gap command value ΔS ^SET .

  According to Embodiment 2 demonstrated above, the roll gap operation means 10 adjusts the roll gap of a rolling stand so that the influence of roll eccentric disturbance may be reduced. For this reason, the plate | board thickness of the rolling material 13 can be controlled accurately.

  In addition, you may apply the plate | board thickness control apparatus of Embodiment 1 and 2 to mills other than a 4Hi mill. For example, you may apply the said board thickness control apparatus to 2Hi mill comprised by the upper side work roll 2a and the lower side work roll 2b. Further, the plate thickness control device may be applied to a 6Hi mill in which an intermediate roll is added to a 4Hi mill.

  As described above, the sheet thickness control device for a rolling mill according to the present invention can be used for accurately identifying the plasticity coefficient of a rolled material.

  DESCRIPTION OF SYMBOLS 1 Housing, 2a Upper work roll, 2b Lower work roll, 3a Upper backup roll, 3b Lower backup roll, 4 Reduction device, 4a Drive side reduction device, 4b Operation side reduction device, 5 Load detector, 5a Drive side load Detector, 5b Operation side load detector, 6 Roll gap detector, 6a Drive side roll gap detector, 6b Operation side roll gap detector, 7 Rolling load measurement device, 8 Roll gap measurement device, 9 Thickness controller, DESCRIPTION OF SYMBOLS 10 Roll gap operation means, 11 Roll rotation speed detector, 12 Sheet thickness meter, 13 Rolled material, 14 Rolling process, 14a 1st influence coefficient, 14b 2nd influence coefficient, 15 Monitor AGC, 16 Gauge meter AGC, 16a 2nd Control block, 16b PI Your vessels, 16c compensation gain, 17 MMC, 17a third control block, 17b hydraulic roll gap response, 18 a first control block, 19 mils constant identifying unit, 20 plastic coefficient identification device

Claims (13)

A plastic coefficient identification device that identifies a plastic coefficient representing the hardness of the rolled material, based on the actual rolling load value, the actual roll gap value, and the mill constant of the rolling stand to be operated.
A thickness control device for a rolling mill equipped with Mill constant identification device for identifying a mill constant of the rolling stand based on a rolling load actual value and a roll gap actual value of the rolling stand and a thickness of a rolled material on the downstream side of the rolling stand,
With
The sheet thickness control device for a rolling mill according to claim 1, wherein the plastic coefficient identification device identifies the plastic coefficient based on the mill constant identified by the mill constant identification device.   The mill constant identification device is a plate thickness of the rolling material on the downstream side of the rolling stand based on a mass flow constant law using a conveyance speed of the rolling material on the downstream side of the rolling stand and a rotation speed of the rolling roll of the rolling stand. The thickness control apparatus of the rolling mill of Claim 2 which calculates.   The sheet thickness control device for a rolling mill according to claim 2, wherein the mill constant identification device identifies a mill constant of the rolling stand based on a rotational position of a rolling roll of the rolling stand.   The mill constant identification device compensates the transport time from the rolling stand to the plate thickness gauge with respect to the thickness of the rolled material on the downstream side of the rolling stand to obtain a plate thickness measurement value change amount, and the rolling stand Determine the roll gap actual change amount based on the amount of change from the steady value of the roll gap, determine the rolling load actual change amount based on the deviation between the rolling load measurement value of the rolling stand and a preset value, Claims for identifying the mill constant by applying an optimization method to a formula including a change in measured thickness of the sheet, an actual change in the roll gap, an actual change in the rolling load, a rotational position of the rolling roll, and the mill constant. Item 5. A sheet thickness control device for a rolling mill according to Item 4.   The mill constant identification device identifies the mill constant of the rolling stand every time data of one rolled material is obtained for the rolling stand, smoothes it with the past mill constant, and the rolling roll of the rolling stand The sheet thickness control device for a rolling mill according to any one of claims 2 to 5, wherein when the replacement is performed, a ratio of using the latest identification data is set higher than usual.   The sheet thickness control device for a rolling mill according to claim 1, wherein the plastic coefficient identification device identifies the plastic coefficient of the rolled material based on a mill constant obtained by a kiss roll test.   The sheet thickness control of the rolling mill according to any one of claims 1 to 7, wherein the plastic coefficient identification device identifies a plastic coefficient of the rolled material based on a rotational position of a rolling roll of the rolling stand. apparatus.   The plastic coefficient identification device obtains a rolling load actual change amount based on a deviation between a rolling load measurement value of the rolling stand and a preset value, and based on a change amount from a steady value of the roll gap of the rolling stand. The roll gap actual change amount is obtained, and the optimization method is applied to an expression including the rolling load actual change amount, the roll gap actual change amount, the rotation position of the rolling roll, the mill constant, and the plastic coefficient. The plate | board thickness control apparatus of the rolling mill of Claim 8 which identifies the plasticity coefficient of a rolling material.   The said plastic coefficient identification apparatus is a plate | board thickness control apparatus of the rolling mill as described in any one of Claims 1-9 which identifies the plastic coefficient of the said rolling material using the data extract | collected previously.   The plastic coefficient identifying device identifies the plastic coefficient of the rolled material when data of a predetermined number is accumulated for each lot divided by the same or similar steel type, sheet thickness, and rolling temperature range. The plate | board thickness control apparatus of the rolling mill as described in any one of Claims 1-9.   The plasticity coefficient identification device identifies the plasticity coefficient of the rolled material every time data is accumulated in a lot divided by the same or similar steel type, sheet thickness, and rolling temperature range. A sheet thickness control device for a rolling mill according to claim 1. Roll gap operating means for estimating roll eccentric disturbance due to eccentricity of the rolling roll of the rolling stand and adjusting the roll gap of the rolling stand so as to reduce the influence of the roll eccentric disturbance;
The plate | board thickness control apparatus of the rolling mill as described in any one of Claims 1-12 provided with these.

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