JP6045420B2 - Hot tandem rolling mill control apparatus and hot tandem rolling mill control method - Google Patents

Description

  The present invention relates to a hot tandem rolling mill control device and a control method for a hot tandem rolling mill.

  In a hot tandem rolling mill, in addition to the output of the work roll rotation speed (hereinafter simply referred to as “speed”), torque, motor power, etc. of each rolling stand not being excessive, the balance between adjacent rolling stands is important. In particular, if the speed balance between the rolling stands is not good, the steel plates sag or stretch between the rolling stands, resulting in unstable rolling and quality deterioration of the steel plates. In order to increase the production volume, it is necessary to increase the rolling speed, but if the speed and torque of a specific rolling stand are limited by the upper limit of the equipment during rolling, the speed balance between the rolling stands will be disrupted, The inconvenience described above occurs.

  In order to solve the above inconvenience, Patent Document 1 discloses a technique of rolling using the upper limit of equipment specifications of a hot tandem rolling mill to maximize the production amount. The method disclosed in Patent Document 1 estimates the rolling torque at the time of width direction reduction from the width reduction amount of the width direction press facility, and performs rolling at the maximum speed at which the estimated rolling torque can be generated. is there. Thereby, the width rolling time by a press apparatus is shortened and the maximum capability of a press apparatus is exhibited.

  Further, Patent Document 2 discloses a technique for preventing the output of a specific rolling stand from being limited by an upper limit as a result of increasing the output of the equipment and losing the roll speed balance between the rolling stands. In the method disclosed in Patent Document 2, the torque applied to the work roll of each rolling stand is dynamically balanced during rolling, and the production amount is increased without overloading the motor.

JP 2006-231364 A JP-A-2005-95975

  However, these conventional techniques have the following problems. In a hot tandem rolling mill, the rolling speed of the final rolling stand (work roll rotation speed) is usually a constant value. And the disorder of the speed balance between the rolling stands by the change of the rolling position and looper height in each rolling stand during rolling is compensated by the change of the roll speed of the upstream rolling stand. If the speed of a specific rolling stand reaches the upper limit as a result of compensation, the speed balance between the rolling stands cannot be maintained. Therefore, because of the need to secure this compensation, the maximum value of the rolling speed in the set-up calculation performed prior to rolling needs to be set to a value obtained by subtracting a certain ratio from the equipment upper limit value as a margin. In Patent Document 1, this point is not taken into consideration, and the rolling speed is determined based on the maximum value of the equipment specification. Therefore, it cannot be applied as it is to the speed control of the hot tandem rolling mill.

  On the other hand, if the margin is a large value, the risk that the output of each rolling stand reaches the upper limit is reduced, but the equipment specifications that can be originally exhibited cannot be sufficiently exhibited. For this reason, productivity may fall or it may become impossible to control steel plate temperature to a target value from the fall of rolling speed. Conversely, when the margin is set to a small value, each rolling stand can be operated in a state close to the maximum value of the equipment specification, but the risk that a specific rolling stand reaches the upper limit value of the equipment specification during rolling increases. When a specific rolling stand reaches the upper limit of the equipment specification during rolling, there is a problem that rolling becomes unstable because the balance of the rolling speed between the rolling stands cannot be solved.

  From the above, it is necessary to set the margin, which is the difference between the equipment upper limit value and the maximum rolling speed, to an appropriate value. In the method described in Patent Document 2, there is no description regarding consideration of this point, and it is not clear how to deal with a specific motor that is overloaded during rolling.

  In view of the above situation, there has been a demand for a method of suppressing the disorder of the speed balance between rolling stands during rolling while maximizing the capacity of the facility.

A hot tandem rolling mill control device according to one aspect of the present invention is a hot tandem rolling mill provided with a plurality of rolling stands, and continuously controls the rolling of a steel sheet with a work roll provided in the rolling stands. In the hot tandem rolling mill control device, the following configuration is adopted.
Focusing on the fact that the risk that the rolling speed reaches the upper limit differs depending on the characteristics of the steel sheet, the speed margin can be set for each steel sheet, and the maximum value of the rolling speed that can be set by the setup calculation is optimized.
Here, when the rolling speed of a specific rolling stand reaches the upper limit of the roll speed during rolling, control is performed so as to reduce the rolling speed of each rolling stand of the hot tandem rolling mill. It is more desirable to minimize the balance disturbance.

  ADVANTAGE OF THE INVENTION According to this invention, disorder of the speed balance between the rolling stands during rolling can be suppressed, optimizing a speed margin and exhibiting the capability of an installation to the maximum.

It is a block diagram which shows the structural example of the hot tandem rolling mill control apparatus which concerns on the 1st Embodiment of this invention. It is a flowchart which shows the process example of the setup part of FIG. It is explanatory drawing which shows the structural example of the draft schedule table of FIG. It is explanatory drawing which shows the structural example of the speed pattern table of FIG. It is a flowchart which shows the process example of the speed upper limit determination part of FIG. It is explanatory drawing which shows the structural example of the speed margin table of FIG. It is a flowchart which shows the process example of the upper limit speed determination part of FIG. It is explanatory drawing which shows the structural example of the dynamic speed upper limit table of FIG. It is a flowchart which shows the process example of the speed command correction part of FIG. It is a flowchart which shows the process example of the speed instruction | command correction part which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the structural example of the hot tandem rolling mill control apparatus which concerns on the 3rd Embodiment of this invention. These are block diagrams which show the structural example of the hardware of a computer.

Hereinafter, an example of an embodiment for carrying out the present invention will be described with reference to the accompanying drawings. In addition, in each figure, the same code | symbol is attached | subjected to the common component and the overlapping description is abbreviate | omitted.
In the embodiment described below, focusing on the fact that the risk that the rolling speed reaches the upper limit depends on the characteristics of the steel sheet and the speed margin is different, it can be set for each steel sheet, and the maximum rolling speed that can be set by the setup calculation The values are appropriate. In addition, when the rolling speed of a specific rolling stand reaches the upper limit during rolling, this is a technique for minimizing the disorder of the speed balance between the rolling stands.

<1. First Embodiment>
FIG. 1 is a block diagram showing a configuration of a hot tandem rolling mill control device according to an embodiment of the present invention.
The hot tandem rolling mill control device 100 receives various signals such as operation results from the control object 150 and outputs control signals to the control object 150. First, the configuration of the control target 150 will be described.

[Control target (finishing mill)]
The controlled object 150 is a hot tandem rolling mill composed of a plurality of rolling stands (hereinafter, simply referred to as “stands”). In the example of FIG. 1, the finishing mill 151 has a configuration in which seven rolling stands 152 (F1 to F7) are continuously arranged along the conveyance direction of the rolled material. The rolled material moves from left to right in the figure. In addition, in the following description, when it is necessary to distinguish seven rolling stands, it distinguishes using the code | symbol of F1-F7.

  For example, the rough material 160 having a thickness of about 30 mm produced by the roughing mill (not shown), which is the preceding process, is sequentially thinned by rolling at each rolling stand 152 of the finishing mill 151. Then, the steel sheet 161 of about 1 mm to 10 mm is finally paid out on the outlet side of the most downstream rolling stand (hereinafter referred to as “final stand”) F7. It is a pair of work rolls 153 provided in each rolling stand 152 that performs rolling while directly pressing the rough material 160 and the steel plate 161. In the following description, “roll speed” means the peripheral speed of the work roll 153. In the present embodiment, a plate thickness meter 154 for measuring the plate thickness of the steel plate 161 is provided on the exit side of the final stand F7 of the finishing mill 151.

  In hot tandem rolling, if the balance of roll speeds between rolling stands is lost, sufficient steel sheet tension cannot be secured between rolling stands, unstable rolling occurs, and conversely, high tension causes the plate thickness and width to be reduced. Shrinkage and steel plate quality may deteriorate. For this reason, it is necessary to operate all the rolling stands 152 at a harmonious roll speed at the time of feeding. At this time, the reference for the operation is the reference rolling speed. In this embodiment, the reference rolling speed is calculated by the following procedure.

  First, a rolling stand (reference stand) serving as a reference for calculating the rolling speed is set as the most downstream rolling stand (final stand). The maximum rolling speed of the work roll 153 of the final stand F7 is calculated from the maximum motor rotation speed of the work roll 153 of the final stand F7, the gear ratio between the motor system and the roll system, and the work roll diameter. A value obtained by dividing the rolling speed command value of the final stand F7 by the maximum rolling speed is defined as “reference rolling speed”. That is, the reference rolling speed is represented by the ratio between the rolling speed command value of the reference stand (the final stand in the present embodiment) and the maximum rolling speed. Based on this reference rolling speed, the rolling speed of each rolling stand is determined.

Here, the upper limit value (hereinafter referred to as “upper limit roll speed”) of the roll speed of each rolling stand 152 determined from the power and torque of the motor, the rotation capability of the motor and the like is calculated. When a certain rolling condition (rolling specification) is given, a rolling stand (hereinafter referred to as a “rate-limiting stand”) that first reaches the upper limit roll speed when the reference rolling speed is increased is specified. Then, the reference rolling speed corresponding to the maximum speed of the rate-limiting stand is defined as the maximum value of the reference rolling speed under this rolling condition.
In addition to the reference rolling speed Vr_std, an individual speed command Vri_ss is given to each rolling stand 152, and the work roll speed command Vri_ref given to each rolling stand 152 is a reference rolling speed as shown in the following equation (1). It is a value obtained by multiplying Vr_std and individual speed command Vri_ss. Conversely, the individual speed command Vri_ss is a value obtained by dividing the work roll speed command Vri_ref by the reference rolling speed Vr_std.

(Equation 1)
Vri_ref = Vri_ss × Vr_std (1)

[Configuration of hot tandem rolling mill controller]
Next, the configuration of the hot tandem rolling mill control device 100 will be described.
As shown in FIG. 1, the hot tandem rolling mill control device 100 includes a setup unit 101, a speed margin table 102, a speed upper limit determination unit 103, a draft schedule table 104, a speed pattern table 105, and a constant table. 130 is provided. Further, the hot tandem rolling mill control device 100 includes a result collecting unit 106, a dynamic speed upper limit table 107, an upper limit speed determining unit 108, a speed command correcting unit 109, a reduction position control unit 120, and a speed control unit 121. And. The hot tandem rolling mill control device 100 can be configured using, for example, a computer.

  The setup unit 101 receives information necessary for rolling such as a steel type, a target plate thickness, and a target plate width from the host computer 50 prior to rolling for each of the steel plates to be rolled. Then, the setup unit 101 refers to the draft schedule table 104 and the speed pattern table 105, and the rolling position (roll gap) of the work roll 153 with respect to each rolling stand 152, the roll speed of the work roll 153 (the work roll circumference) Speed), rolling load, etc.

  The speed margin table 102 stores a margin value (hereinafter also referred to as “speed margin”) that is a margin for the maximum value of the reference rolling speed.

  The speed upper limit determination unit 103 calculates the upper limit roll speed of each rolling stand 152 and outputs the calculation result to the dynamic speed upper limit table 107. Further, the speed upper limit value determining unit 103 calculates the upper limit value of the reference rolling speed command that is allowed to be set in the setup calculation for the steel sheet to be rolled next time from the reference rolling speed margin extracted from the speed margin table 102, 101.

  The performance collection unit 106 collects information on the rolling performance of the finishing mill 151 that is the control target 150.

  The upper limit speed determination unit 108 determines whether each rolling stand 152 is based on the roll speed record data of each rolling stand 152 collected by the result collecting unit 106 and the upper limit roll speed of each rolling stand 152 stored in the dynamic speed upper limit table 107. Determine if the speed limit is exceeded.

  The speed command correcting unit 109 performs a process of reducing the speed command of each rolling stand 152 when the upper limit speed determining unit 108 determines that any of the rolling stands 152 exceeds the upper limit roll speed.

  The speed control unit 121 performs speed control using the speed command value output from the setup unit 101, the correction value of the speed command obtained from the speed command correction unit 109, and the roll speed actual value obtained from the result collection unit 106.

  The reduction position control unit 120 responds to a reduction position command for an arbitrary rolling stand 152 output from the setup unit 101 with a difference between the actual plate thickness measured by the plate thickness meter 154 and the target plate thickness (plate thickness deviation). ) Etc. are used to control the actual reduction position.

  The configurations of the draft schedule table 104 (FIG. 3), the speed pattern table 105 (FIG. 4), the speed margin table (FIG. 6), and the dynamic speed upper limit table 107 (FIG. 8) will be described later.

Hereinafter, the operation of each part of the hot tandem rolling mill control device 100 will be described in detail.
FIG. 2 is a flowchart showing processing executed by the setup unit 101.
The setup unit 101 receives information necessary for rolling such as a steel type, a target plate thickness, and a target plate width from the host computer 50, and then performs a process of calculating a control command for the rough material 160 to be rolled.

  First, the setup unit 101 fetches a draft schedule, which is information corresponding to how much the coarse material 160 and the steel plate 161 are thinned in each of the rolling stands 152, from the corresponding items in the draft schedule table 104. Further, the setup unit 101 takes in a speed pattern from the speed pattern table 105 (step S1).

FIG. 3 is an explanatory diagram showing a configuration example of the draft schedule table 104.
As shown in FIG. 3, the draft schedule table 104 stores a value rolled by each rolling stand 152 for the thickness difference between the coarse material 160 and the steel plate 161 as percentage information (percentage value) with respect to the thickness difference. ing. Each draft schedule is stratified into records according to the type of steel sheet to be rolled, the target plate thickness, and the target plate width.

For example, a rough material 160 having a plate thickness of 35 mm and a steel type of SS400, a target plate thickness of 2.5 mm, and a target plate width of 900 mm is assumed. In FIG. 3, the draft schedule for the rough material 160 corresponds to a section in which the target plate thickness is 2.0 to 3.0 mm and the target plate width is 1000 mm or less. Since the rough material 160 with a plate thickness of 35 mm is rolled into the steel plate 161 with a plate thickness of 2.5 mm, with respect to the plate thickness difference of 32.5 mm, in the example of FIG. The rolling stand F2 on the side shows that 16% is rolled.
That is, in the rolling stand F1, as shown in the following formula (2),
(Equation 2)
32.5mm × 24/100 = 7.8mm (2)
Therefore, it is shown that a 35 mm rough material should be rolled to 27.2 mm (35 mm-7.8 mm). Similarly,
(Equation 3)
32.5mm × 16/100 = 5.2mm (3)
Therefore, the rolling stand F2 indicates that a 27.2 mm plate should be rolled to 22.0 mm (27.2 mm-5.2 mm). For a certain record, the sum of the numerical values of the rolling stands 152 in the draft schedule is 100. When the same calculation procedure is repeated, the exit side plate thickness of the final stand F7 becomes 2.5 mm, which is the target plate thickness. In this way, the setup unit 101 searches for the corresponding record in the draft schedule table 104 from the steel type, thickness, and width of the steel sheet to be rolled next time received from the host computer 50 in step S1, and Take in the rolling amount (percentage).

FIG. 4 is an explanatory diagram illustrating a configuration example of the speed pattern table 105.
The speed pattern table 105 stores the speed at each stage of rolling for each rolling condition such as the steel type of the steel plate 161, the target plate thickness, and the target plate width. That is, for each rolling condition, the tail end of the steel plate 161 is rolled from the speed (initial speed) when the tip of the steel plate 161 is discharged from the final stand F7, and the subsequent first acceleration, second acceleration, maximum speed, and maximum speed. In this case, the deceleration when decelerating to the final speed and the final speed are accumulated.

  The setup unit 101 determines the steel type, plate thickness, and plate width of the steel plate 161 and extracts the corresponding speed pattern from the speed pattern table 105. For example, it is assumed that the steel type is SUS304, the plate thickness is 2.0 to 3.0 mm, and the plate width is 100 mm or less. In the case of this rolling condition, it is shown that the initial speed is 650 mpm, the first acceleration is 2 mpm / s, the second acceleration is 12 mpm / s, the steady speed is 800 mpm, the deceleration is 6 mpm / s, and the final speed is 700 mpm.

  Next, the setup unit 101 estimates the rolling temperature (step S2). The temperature of the coarse material 160 and the steel plate 161 is estimated by combining a value detected by a thermometer (not shown) and a temperature prediction calculation considering heat radiation, heat transfer, and the like. Many temperature estimation methods have been introduced in thermodynamic literature, etc. Further, temperature changes in rolling are described in detail in Chapter 6 (Temperature changes in rolling) of “Theory and practice of plate rolling (Japan Iron and Steel Institute)”, for example. Detailed explanation is omitted.

  Next, the setup unit 101 calculates a deformation resistance, which is a value corresponding to the hardness of the steel sheet rolled at each rolling stand (step S3). The deformation resistance of steel sheets is described in various documents, and is described in detail in Chapter 7 (deformation resistance) of “Theory and Practice of Sheet Rolling (Japan Iron and Steel Institute)”, for example. As a representative calculation formula of deformation resistance, it is expressed by the following formula (4) using the estimated steel plate temperature T at the time of rolling (“Theory and Actuality of Plate Rolling” 7.54 formula).

(Equation 4)
Kf = Kε ⁿ (dε / dt) ^m exp (A / T) (4)
Where ε: strain, (dε / dt): strain rate
K, n, m, A: Constants determined for each steel type

  Next, the setup unit 101 calculates the roll speed of each rolling stand 152 (step S4). Since the speed pattern taken in step S1 is the plate speed on the exit side of the final stand F7, the exit side plate speed of each rolling stand 152 is calculated based on this speed by the following procedure. First, the exit side plate speed of each rolling stand 152 is calculated by the following equation (5).

(Equation 5)
Vsi = Vs7 x hi / h7 (5)
Vsi: Exit side plate speed of i-th stand
hi: Outboard thickness of the i-th stand
h7: Outboard thickness of the 7th stand (final stand)

Subsequently, using the advanced rate, the roll speed of each rolling stand 152 is calculated from the exit side plate speed of each rolling stand 152. The advanced rate is the ratio of the roll speed to the exit side plate speed, and there is a relationship of the following formula (6).
(Equation 6)
Vri = Vsi / fi (6)
Vri: roll speed of i-th stand
fi: Advanced rate of the i-th stand The advanced rate is also described in Chapter 2 (two-dimensional rolling theory) of “Theory and Practice of Sheet Rolling”. For example, using the function g1, the following equation (7) It is widely known that the relational expression is as follows.

(Equation 7)
f = g1 (H, h, R´, tb, tf, kf) (7)
Where f: advanced rate, H: entrance side thickness of rolling stand, h: exit side thickness of rolling stand,
R ′: flat roll diameter, tb: backward tension of steel plate, tf: forward tension of steel plate,
kf: Deformation resistance

The above formula (6) is calculated for each rolling stand, and the roll speed of each rolling stand 152 is obtained.
Further, the setup unit 101 calculates the rolling load of each rolling stand 152 (step S5). The calculation method of the rolling load is also described in Chapter 2 (Two-dimensional rolling theory) of “Sheet rolling theory and practice”. The rolling load increases as the deformation resistance increases, and as the inlet side plate thickness increases and the output side plate thickness decreases, and is expressed by the following relational expression using the function g2.

(Equation 8)
p = g2 (H, h, R´, tb, tf, Kf, Qp, Qs) ... (8)
Where p: rolling load, Qp: peening effect, Qs: rolling force function

Furthermore, the setup unit 101 outputs a parameter for the speed upper limit determination unit 103 to calculate the upper limit speed to the speed upper limit determination unit 103 as a speed limit value calculation parameter (step S6). There are various parameters, but they are broadly classified into those received from the host computer 50, those obtained by the setup calculation of the setup unit 101, and those stored in the constant table 130.
The information received from the host computer 50 includes the work roll diameter of each rolling stand 152 and the steel sheet tension on the entry side and the exit side. Moreover, what was calculated | required by setup calculation includes the load of each rolling stand 152, and the board thickness of an entrance side and an exit side. Further, what is read from the constant table 130 includes the gear ratio between the motor and the work roll, the maximum rotational speed of the motor, the maximum torque, and the maximum power.

  Next, the setup unit 101 receives, from the speed upper limit determination unit 103, the upper limit value Vr_std_pos of the reference rolling speed permitted in the current setup calculation as a calculation result (step S7). A method for calculating the upper limit value Vr_std_pos of the reference rolling speed will be described as the processing content of the speed upper limit determination unit 103.

  Next, the setup unit 101 determines whether the steady speed of the work roll of each rolling stand 152 calculated in step S4 exceeds the allowable roll speed that can be set in the setup calculation (step S8). The allowable value Vri_pos of the work roll speed of each rolling stand 152 can be calculated by the following formula (9) using the maximum speed Vr7_max_org derived from the maximum motor rotation speed of the final stand F7 which is the speed reference stand.

(Equation 9)
Vri_pos = Vr7_max_org × Vr_std_pos × (h7 / hi) × (f7 / fi) (9)

Here, the maximum speed Vr7_max_org is obtained by the following equation (10).
(Equation 10)
Vr7_max_org = Mr7_max × (2 × π × R7) / G7 (10)
However, Mr7_max: Maximum number of rotations of the work roll 153 motor of the final stand F7
G7: Gear ratio between the motor system of the last stand F7 and the roll diameter
R7: Radius of work roll 153 of final stand F7

  When the steady speed of the work roll 153 of each rolling stand 152 does not exceed the allowable roll speed that can be set by the setup calculation, the setup unit 101 reduces the roll position (roll gap) of the work roll 153 in step S9. Is calculated (step S9). In general, the basic part of the calculation of the reduction position is represented by the following relational expression (11), but various correction terms are actually added to increase the calculation accuracy.

(Equation 11)
S = hp / K (11)
Where S: Rolling position, p: Rolling load, K: Mill spring constant

  When the steady speed of the work roll 153 of any of the rolling stands 152 exceeds the allowable roll speed that can be set by the setup calculation in the determination process of step S8, the speed pattern stored in the speed pattern table 105 is stored. Correction is performed (step S10). A process of reducing the steady roll speed of the i-th stand exceeding the allowable value of the roll speed of the work roll 153 to the allowable value Vri_pos of the work roll speed is performed. As a result, the steady speed V_stab fetched from the speed pattern table 105 is corrected to a value according to the following equation (12).

(Equation 12)
V_stab = Vri_pos × (1 + fi) × hi / h7 (12)
However, fi: Advanced rate of i-th stand, hi: Outboard thickness of i-th stand,
h7: Outboard thickness of the final stand F7

  After the process of step S10 is completed, the process from step S2 is executed again.

FIG. 5 is a flowchart showing processing executed by the speed upper limit determination unit 103.
First, the speed upper limit determination unit 103 takes in the speed limit value calculation parameter output from the setup unit 101 (step S11).

  Next, the speed upper limit determination unit 103 calculates the upper limit roll speed of each rolling stand of the rolling stands F1 to F7 in the process of step S12. The upper limit roll speed is associated with the minimum value among the roll speed corresponding to the upper limit of the motor maximum rotation speed, the roll speed corresponding to the upper limit of the rolling torque, and the roll speed corresponding to the upper limit of the motor power. For example, the roll speed Vri_max1 corresponding to the upper limit of the maximum motor speed of the i-th stand is given by the following equation (13).

(Equation 13)
Vri_max1 = Mri_max × (2 × π × Ri) / Gi (13)
However, Mri_max: Maximum motor rotation speed, Gi: Gear ratio, Ri: Work roll 153 radius

The rolling torque Tr of each rolling stand 152 is given by the following equation (14) using the function g3, for example.
(Equation 14)
Tr = g3 (Vr, R, R ', H, h, P, tb, tf, b, GL) ... (14)
Where Vr: roll speed, R: roll diameter, R ′: flat roll diameter, H: entry side plate thickness,
h: Outboard thickness, P: Rolling load, tb: Back tension, tf: Front tension,
b: Sheet width of rolled material, GL: Constant term of loss torque

The rolling torque is also described in Chapter 2 (Two-dimensional rolling theory) of "Plate rolling theory and practice". Therefore, the roll speed Vri_max2 corresponding to the upper limit Tri_max of the rolling torque of the i-th stand is expressed by the following equation (15).
(Equation 15)
Vri_max2 = g3 ^-1 (Tri_max, Ri, Ri´, Hi, hi, Pi, tbi, tfi, bi, GLi) ... (15)

The motor power Mp is given by the following equation (16), for example.
(Equation 16)
Mp = a × Vr × Tr / R (16)
Where a: coefficient, Vr: roll speed, R: roll diameter, Tr: torque

Therefore, the roll speed Vri_max3 corresponding to the upper limit Mpi_max of the motor power of the i-th stand is expressed by the following equation (17).
(Equation 17)
Vri_max3 = Mpi_max × Ri / (a × Tr) (17)

From the above description, the upper limit value Vri_max of the roll speed of the i-th stand corresponding to the steel sheet to be rolled next time is expressed by the following equation (18).
(Equation 18)
Vri_max = Min (Vri_max1, Vri_max2, Vri_max3) (18)

  The speed upper limit determination unit 103 outputs the upper limit value of the roll speed of each rolling stand 152 calculated by the equation (18) to the dynamic speed upper limit table 107 (step S12).

Next, when the reference rolling speed Vr_std is increased, the speed upper limit determining unit 103 first identifies the rolling stand 152 that reaches the upper limit, and sets this as the rate-limiting stand (step S13). The value of the reference rolling speed (the maximum value of the reference rolling speed) corresponding to the upper limit speed of this rate-limiting stand is defined as Vr_std_max. The rate-limiting stand is specified by the following formula (19).
(Equation 19)
Min (α1 ・ Vr1_max, α2 ・ Vr2_max, ..., Vr7_max) ... (19)

Here, αi is a coefficient for converting the roll speed of the i-th stand into the roll speed of the final stand, and the following formula (from the advanced rate and outlet side thickness of each rolling stand 152, and the advanced rate and outlet side thickness of the final stand: 20).
(Equation 20)
αi = (1 + fi) × hi / {(1 + f7) × h7} (20)
However, fi: Advanced rate of i-th stand, hi: Outboard thickness of i-th stand,
f7: Advanced rate of final stand (F7), h7: Outboard thickness of final stand (F7)

Next, the speed upper limit determination unit 103 calculates the maximum value Vr_std_max of the reference rolling speed (step S14). As a result of the equation (19), when the j-th stand is a rate-limiting stand, the maximum value Vr_std_max of the reference rolling speed is given by the following equation (21).
(Equation 21)
Vr_std_max = (αj · Vrj_max / Vr7_max_org) (21)

  Next, the speed upper limit determination unit 103 takes in the value of the speed margin from the speed margin table 102 (step S15).

FIG. 6 is an explanatory diagram showing a configuration example of the speed margin table 102.
As described above, the speed margin V_mar indicates the difference between the maximum value Vr_std_max of the reference rolling speed and the reference rolling speed Vr_std_pos that can actually be set in the setup calculation, and these relations Is given by the following equation (22). However, Vr_std_pos is a speed limit value of the work roll 153 of the rolling stand 152 (hereinafter referred to as “speed limit value”).
(Equation 22)
Vr_std_pos = Vr_std_max-V_mar (22)

  FIG. 6 shows an example in which the speed margin V_mar is stored corresponding to the steel type, plate thickness, and plate width of the steel plate 161. In FIG. 6, for example, when the steel type is SS400, the plate thickness is 2.0 to 3.0 mm, and the plate width is 1000 mm or less, the speed margin V_mar is 0.10. That is, it indicates that the setting of the reference rolling speed reduced by 0.1 with respect to the maximum value Vr_std_max of the reference rolling speed is allowed.

  The speed upper limit determination unit 103 outputs the speed limit value Vr_std_pos to the setup unit 101 (step S16).

  The reduction position control unit 120 corrects the reduction position command received from the setup unit 101 to reflect the change in the actual rolling load and the difference between the actual plate thickness detected by the plate thickness meter 154 and the target plate thickness. Is output to the control object 150. The reduction position control is called AGC (Automatic Gauge Control), and various methods such as Bisra AGC, Monitor AGC, and Gauge meter AGC are known. In addition, when the rolling position changes, the mass flow values of the inlet side steel plate and the outgoing side steel plate change. To compensate for this, the rolling stand whose rolling position has changed and the upstream rolling as viewed from this rolling stand. It is necessary to change the roll speed of the stand. Such a speed command correction amount (speed correction amount) is output from the reduction position control unit 120 to the speed control unit 121.

Further, the speed control unit 111 performs speed control of the work roll 153 using a value obtained by adding the speed correction amount to the speed command output from the setup unit 101 as a command value. As the speed correction amount, in addition to the value output from the reduction position control unit 120, in order to maintain the speed balance of the tandem rolling, a value corresponding to the speed command change amount of the downstream rolling stand is set to the upstream rolling stand. There is a speed correction amount in so-called passive control (hereinafter, also referred to as “successive correction amount”) that is sequentially propagated as a speed correction amount. That is, when the speed of the i + 1th stand is changed by Vr (i + 1) _comp, it is necessary to change the roll speed of the upstream ith stand by Vri_sc to maintain the tandem rolling speed balance. The successful speed correction amount of the i-th stand can be calculated using, for example, the following equation (23) using the speed change amount of the i + 1th stand on the downstream side.
(Equation 23)
Vri_sc = Gsc × [Vr (i + 1) _comp] × (Vri / Vr (i + 1)) (23)
Where Vri_sc is the amount of successful correction for the i-th stand
Vr (i + 1) _comp: Speed command change amount for the i + 1th stand
Vri: i-stand roll speed
Vr (i + 1): Roll speed of stand i + 1
Gsc: Constant

  Further, when there is a rolling stand on the upstream side of the i-th stand, processing for correcting the speed command of the i-th stand is performed using Vri_sc as the speed change amount. This process is sequentially performed until the speed command of the rolling stand F1 on the most upstream side is corrected. The speed control unit 121 includes a speed command and a result collecting unit for each rolling stand 152 obtained by adding the speed command received from the setup unit 101, the speed correction amount received from the reduction position control unit 120, and the subsequent speed correction amount. Speed control is performed to reduce the deviation from the actual speed obtained from 106. The speed control system is composed of, for example, a proportional / integral control system called ASR (Automatic Speed Control).

FIG. 7 is a flowchart showing processing executed by the upper limit speed determination unit 108.
The upper limit speed determination unit 108 is activated in response to a rolling start trigger, and performs a process of determining whether there is a rolling stand 152 that exceeds the upper limit value of the roll speed during rolling.

  First, the upper limit speed determination unit 108 takes in the upper limit value of the roll speed of each rolling stand 152 from the dynamic speed upper limit table 107 (step S21).

FIG. 8 is an explanatory diagram showing a configuration example of the dynamic speed upper limit table 107.
The dynamic speed upper limit table 107 stores the roll speed upper limit value (denoted as the maximum speed in FIG. 8) of each rolling stand 152 calculated and output by the speed upper limit determination unit 103 for the steel sheet to be rolled next time. . In the example of FIG. 8, for example, information (record) is stored that the upper limit roll speed of the rolling stand F1 is 320 mpm. Similarly, roll speed upper limit values of the rolling stands F2 to F7 are stored.

  Next, the upper limit speed determining unit 108 takes in the actual value of the roll speed of each rolling stand 152 from the actual result collecting unit 106 (step S22).

  Next, the upper limit speed determination unit 108 compares the roll speed upper limit value and the actual value of each rolling stand 152, and determines whether there is a rolling stand 152 that exceeds the roll speed upper limit value (step S23).

  If there is a rolling stand 152 that exceeds the upper limit speed in the determination process of step S23, the upper limit speed determination unit 108 notifies the speed command correction unit that the upper limit speed has been exceeded (step S24). On the other hand, when there is no rolling stand 152 that exceeds the upper limit speed, the upper limit speed determination unit 108 proceeds to the determination process of step S25.

  The upper limit speed determination unit 108 determines whether or not the rolling of the steel plate 161 has been completed (step S25). If the rolling has been completed, the process by the upper limit speed determining unit 108 is finished. If the rolling has not been finished, the processes of steps S22 to S25 are repeated.

FIG. 9 is a flowchart showing processing executed by the speed command correction unit 109.
Similar to the upper limit speed determination unit 108, the speed command correction unit 109 is activated upon receiving a rolling start trigger and performs a process of determining whether there is a rolling stand 152 that has exceeded the roll speed upper limit value.

  First, the speed command correction unit 109 determines whether or not the rolling of the steel plate 161 has been completed (step S31). If the rolling has been completed, the processing by the speed command correcting unit 109 is completed. If the rolling has not been completed, the process proceeds to step S32.

  Next, when the rolling has not ended in step S31, the speed command correcting unit 109 determines whether or not there is a notification that there is an upper limit speed excess stand from the upper limit speed determining unit 108 (step S32).

  In the determination process of step S32, when there is no notification that there is an upper limit speed excess stand, the speed command correction unit 109 repeats the processes of steps S31 to S32. On the other hand, if the upper limit speed determination unit 108 notifies that there is an upper limit speed excess stand, the speed control unit 121 is instructed to decrease the roll speed of the final stand F7 (step S33). When the roll speed of the final stand F7 is corrected, the roll speed of the upstream rolling stand 152 is sequentially corrected by the successive control based on Expression (20), and the speed balance of each rolling stand 152 is maintained.

  After the process of step S33 is complete | finished, the speed command correction part 109 transfers to step S31, and repeats the process of step S31-step S33 during rolling.

As described above, in the present embodiment, the speed margin table 102 stores the margin (margin) from the upper limit value of the reference rolling speed in association with at least one of the steel type, sheet thickness, and sheet width of the steel sheet. ing.
The speed upper limit value determining unit 103 calculates the rolling torque and motor power of each rolling stand 152 from the rolling load and rolling speed calculated in the setup calculation prior to rolling, and by comparing these with the respective upper limit values, A speed limit value (allowable reference rolling speed) of the rolling stand 152 is calculated.
In consideration of the reference rolling speed margin (V_mar) extracted from the speed margin table 102 in association with the specifications of the steel sheet to be rolled next time, the reference value (roll speed upper limit value) of the steel sheet to be rolled next time is determined. To do.
Moreover, the speed upper limit determination unit 103 outputs the upper limit speed (roll speed upper limit value) of each rolling stand 152 to the dynamic speed upper limit table 107.

  On the other hand, during rolling, the upper limit speed determination unit 108 takes in the actual rolling speed value of each rolling stand 152 and refers to the value of the dynamic speed upper limit table 107 to determine the presence or absence of the rolling stand 152 exceeding the upper limit speed. If there is a rolling stand 152 that exceeds the upper limit speed, the speed command correction unit 109 is notified of that fact. When it is determined that the specific rolling stand 152 exceeds the upper limit speed, the speed command correcting unit 109 reduces the roll speed of the final stand in order to eliminate the excessive speed of the corresponding rolling stand.

Thus, by optimizing the speed margin of the reference rolling speed according to the rolling conditions (rolling specifications), it is possible to set the speed for the work roll to maximize the equipment capacity.
Further, when the roll speed reaches the upper limit at a specific rolling stand during rolling, the rolling can be continued in a state where the balance of the tandem rolling speed is maintained by performing a process of reducing the rolling speed with the final stand as a base point.

  As a result, in the hot tandem rolling mill, it is possible to perform rolling that maximizes the equipment capacity of each rolling stand. Therefore, the rolling speed and productivity can be increased, and stable rolling and high quality steel sheet can be realized by suppressing the disorder of the speed balance between the stands during rolling.

<2. Second Embodiment>
As a second embodiment of the present invention, an example in which the speed command correcting unit 109 reduces the value of the reference rolling speed instead of the value of the roll speed of the final stand when there is an upper limit speed excess stand will be described.

FIG. 10 is a flowchart showing processing executed by the speed command correction unit 109 according to the second embodiment of the present invention.
First, the speed command correction unit 109 determines whether or not the rolling of the steel plate 161 has been completed (step S41). If the rolling has been completed, the processing by the speed command correcting unit 109 is completed. If the rolling has not been completed, the process proceeds to step S42.

  Next, when the rolling has not ended in step S41, the speed command correction unit 109 determines whether or not there is a notification that there is an upper limit speed excess stand from the upper limit speed determination unit 108 (step S42).

  In the determination process of step S42, when there is no notification that there is an upper limit speed excess stand, the speed command correction unit 109 repeats the processes of steps S41 to S42. On the other hand, when the upper limit speed determination unit 108 notifies that there is an upper limit speed excess stand, the speed control unit 121 is instructed to decrease the command value of the reference rolling speed (step S43). When the reference rolling speed is corrected, the roll speed of each rolling stand 152 is sequentially corrected by the successive control based on the formula (20) with the reference stand as a base point, and the speed balance of each rolling stand 152 is maintained.

  After the process of step S43 is complete | finished, the speed command correction | amendment part 109 transfers to step S41, and repeats the process of step S41-step S43 during rolling.

  As a reduction amount of the reference rolling speed, a predetermined constant value such as 0.01 may be reduced, or a predetermined constant ratio such as 2% may be reduced. As a result, the roll speeds of the respective rolling stands 152 are simultaneously reduced while maintaining the balance of the tandem rolling.

  According to the second embodiment, the following operations and effects can be obtained in addition to the same operations and effects as those of the first embodiment. When the roll speed reaches the upper limit at a specific rolling stand during rolling, the speed balance of tandem rolling is adjusted by adjusting the reference rolling speed with respect to the reference stand and reducing the rolling speed of each rolling stand 152. Rolling can be continued while maintaining the above.

<3. Third Embodiment>
FIG. 11 is a block diagram showing a configuration example of a hot tandem rolling mill control device according to the third embodiment of the present invention.
Hereinafter, as a third embodiment of the present invention, the first embodiment described above is replaced with an edger 1110, a rough mill 1102 including two rolling stands R1 and R2, and five rolling stands 152 (F1 to F5). The example at the time of applying to the control object 1101 comprised from the finishing mill 1103 provided is shown. Such a configuration of the control object 1101 is called a so-called mini mill.

  In the present embodiment, it is necessary to consider the maximum value of the rolling speed in consideration of the upper limit value of the roll speed of the edger 1110 in addition to the total of seven rolling stands. When the steel plate 1105 is thick, or when the difference in plate thickness between the slab 1104 and the steel plate 1105 is small, the roll speed of the edger 1110 may limit the rolling speed. Even in this case, by applying the configuration realized in the first or second embodiment as it is, it is possible to realize the rolling that exhibits the equipment capability of the hot tandem rolling mill.

  In the first and third embodiments described above, the rolling speed reference stand is the most downstream rolling stand (F7) following general hot rolling control, but the most upstream rolling stand or the like. Other rolling stands can be used as a reference stand for rolling speed.

  Also, when the roll speed reaches the upper limit at a specific rolling stand during rolling, the rolling speed is reduced from the final stand, but the rolling speed of the rolling stands other than the final stand is reduced. Processing may be performed.

  In the first to third embodiments described above, the setup unit 101 is configured to start calculation from the draft schedule and calculate the rolling load, the reduction position, and the roll speed in each rolling stand. In addition to this configuration, a method for starting calculation of each value from the load balance is also known, and the present invention can be similarly applied to this case.

  Moreover, in the 1st-3rd embodiment mentioned above, although the example of the steel grade, board thickness, and board width of a steel plate was demonstrated as rolling conditions, at least one or more of steel grade, board thickness, and board width of a steel plate are included. Anything is acceptable. Alternatively, other items may be added to the rolling conditions.

The present invention is not limited to the above-described embodiments, and includes other modifications and application examples without departing from the gist of the present invention described in the claims.
For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. A part of the configuration of an embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of an embodiment. Is also possible. Further, it is possible to add, replace, or delete other configurations for a part of the configuration of each embodiment.

  Each of the above-described configurations, functions, processing units, processing units, and the like may be realized by hardware, for example, by designing a part or all of them with an integrated circuit. Further, each of the above-described configurations, functions, and the like may be realized by software for interpreting and executing a program that realizes each function by the processor. Information such as programs, tables, and files for realizing each function can be held in a recording device such as a memory, a hard disk, or an SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, or an optical disk. .

  FIG. 12 is a block diagram illustrating a hardware configuration example of a computer (for example, a personal computer) that executes the above-described series of processing by a program.

  In the computer, a CPU 201, a ROM (Read Only Memory) 202, and a RAM 203 are connected to each other via a bus 204.

  An input / output interface 205 is further connected to the bus 204. The input / output interface 205 includes an input unit 206 including a keyboard, a mouse, and a microphone, an output unit 207 including a display and a speaker, a recording unit 208 including a hard disk and nonvolatile memory, and a communication unit 209 including a network interface. Is connected. Furthermore, a drive 210 for driving a removable medium 211 such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory is connected.

  In the computer configured as described above, the CPU 201 loads, for example, the program recorded in the recording unit 208 to the RAM 203 via the input / output interface 205 and the bus 204 and executes the program, and the series described above. Is performed.

  The program executed by the computer (CPU 201) is, for example, a magnetic disk (including a flexible disk), an optical disk (CD-ROM (Compact Disc-Read Only Memory), DVD (Digital Versatile Disc), etc.), a magneto-optical disk, or a semiconductor. The program is recorded on a removable medium 211 that is a package medium composed of a memory or the like, or provided via a wired or wireless transmission medium such as a local area network, the Internet, or digital satellite broadcasting.

  The program can be installed in the recording unit 208 via the input / output interface 205 by attaching the removable medium 211 to the drive 210. Further, the program can be received by the communication unit 209 via a wired or wireless transmission medium and installed in the recording unit 208. In addition, the program can be installed in advance in the ROM 202 or the recording unit 208.

  The program executed by the computer may be a program that is processed in time series in the order described in this specification, or in parallel or at a necessary timing such as when a call is made. It may be a program for processing.

  DESCRIPTION OF SYMBOLS 100 ... Hot tandem rolling mill control apparatus, 101 ... Setup part, 102 ... Speed margin table, 103 ... Speed upper limit determination part, 104 ... Draft schedule table, 105 ... Speed pattern table, 106 ... Performance collection part, 107 ... Dynamic Speed upper limit table 108 108 Upper speed determining unit 109 Speed command correcting unit 120 Rolling position control unit 121 Speed control unit 150 Control target 151 Finishing mill 152 Rolling stand 153 Work roll 160 ... Coarse material, 161 ... Steel plate

Claims (7)

In a hot tandem rolling mill control device that controls a hot tandem rolling mill equipped with a plurality of rolling stands, and continuously controls the rolling of a steel sheet with a work roll provided in the rolling stand,
A speed margin that is a value corresponding to a difference between a maximum value of a reference rolling speed of a predetermined reference stand that is a rolling stand that serves as a reference for calculating a rolling speed of the plurality of rolling stands and a maximum value of a settable rolling speed command. A speed margin table stored in association with rolling conditions;
Calculating the upper limit of the rolling speed of the rolling stands with respect to the steel sheets cast pressure, specific rate-limiting stand rolling stand initially reaches the upper limit of the rolling speed when raising the reference rolling speed of the reference stand and calculates the maximum value of the reference rolling speed corresponding to the upper limit of the rolling speed of該律speed stand, from the maximum value of the reference rolling speed and the speed margin of the speed margin table, which can be actually set A speed upper limit determining unit for determining the maximum value of the rolling speed command;
As a control command for said steel sheet cast pressure, hot tandem rolling mill control and a setup unit that outputs the maximum value of the rolling velocity command to calculate the command value of the roll speed of each rolling stand as an upper limit apparatus. A dynamic speed upper limit table for storing the upper limit value of the rolling speed of each rolling stand calculated by the speed upper limit determination unit;
Captures the actual rolling speed of the rolling stand while rolling the steel sheet, compared with the upper limit of the rolling speed of each rolling stand, which is stored in the dynamic speed limit table, it reaches the upper limit of the rolling speed An upper limit speed determination unit for determining the presence or absence of a rolled stand,
When the upper limit speed determining unit determines that there is a rolling stand that has reached the upper limit value of the rolling speed, a speed command correcting unit that outputs a command for reducing the rolling speed of the rolling stand of the hot tandem rolling mill It equipped with a door,
The hot tandem rolling mill control device according to claim 1, wherein the rolling speed of each rolling stand of the hot tandem rolling mill is reduced based on a command output by the speed command correcting unit. The speed command correcting unit outputs a command to reduce the reference rolling speed of the hot tandem rolling mill when the upper limit speed determining unit determines that there is a rolling stand that has reached the upper limit value of the rolling speed. The hot tandem rolling mill control device according to claim 2. The speed command correcting unit reduces the rolling speed of the rolling stand on the most downstream side of the hot tandem rolling mill when the upper limit speed determining unit determines that there is a rolling stand that has reached the upper limit value of the rolling speed. The hot tandem rolling mill control device according to claim 2, wherein a command to output is output. The speed upper limit determination section, when each rolling stand is rolling the steel sheet, to calculate the rolling torque and the motor power and the maximum rotational speed of the work rolls, which can be set in a range where any of which does not exceed the upper limit value The hot tandem rolling mill control device according to any one of claims 2 to 4, wherein a rolling speed is calculated as an upper limit value of a rolling speed of each rolling stand and is output to the dynamic speed upper limit table. The rolling conditions, the steel grade of at least the steel plate thickness, hot tandem rolling mill control apparatus according to claim 5 comprising one or more plate width. A hot tandem rolling mill in a hot tandem rolling mill control device which controls a hot tandem rolling mill equipped with a plurality of rolling stands and continuously controls the rolling of a steel sheet with a work roll provided in the rolling stand. In the control method,
A speed margin that is a value corresponding to a difference between a maximum value of a reference rolling speed of a predetermined reference stand that is a rolling stand that serves as a reference for calculating a rolling speed of the plurality of rolling stands and a maximum value of a settable rolling speed command. , Store it in the speed margin table in association with the rolling conditions,
Calculating the upper limit of the rolling speed of the rolling stands with respect to the steel sheets cast pressure,
When the reference rolling speed of the reference stand is increased, the rolling stand that first reaches the upper limit of the rolling speed is specified as the rate-limiting stand,
Calculate the maximum value of the reference rolling speed corresponding to the upper limit value of the rolling speed of the rate limiting stand,
From the maximum value of the reference rolling speed and the speed margin table speed margin, to determine the actual maximum value that can be set rolling speed command,
Control as a command, the hot method of controlling tandem rolling mill for calculating the command value of the roll speed of each rolling stand the maximum value of the rolling speed command upper limit for the steel sheet cast pressure.

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