JPS63171211A - Shape control method in plate rolling - Google Patents

Abstract

PURPOSE:To obtain the plate of good shape in the whole plate width by finding the steepness distribution in the plate width direction excluding the detection value of a plate end part and controlling by using four shape evaluation parameters found based on this steepness distribution and the shape evaluation parameter found based on the detection value of the plate end part. CONSTITUTION:A plate shape is detected at the outlet side of a rolling mill to find the steepness distribution in the plate width direction expressed by a biquadratic equation excluding the detection value of a plate end part. The two shape evaluation parameters indicating symmetric component with respect to the plate width center, two parameters indicating asymmetric component and the shape evaluation parameter found based on the detection value of the plate end part are found from the steepness distribution. The plate shape is then controlled by adjusting the operation amt. of a shape controlling means according to these shape evaluation parameters. The plate of good shape at the whole plate width zone can thus be obtd. even if a big lug wave-shaped detect be caused at the plate end part.

Description

Detailed Description of the Invention (Industrial Application Field) This invention relates to a shape control method in plate rolling, in particular a roll bender,
This invention relates to a method for feedback controlling the shape of a board in the width direction by operating roll shift and other functions.

(Conventional technology) In cold rolling, roll benders, roll shifts, coolant supply devices, etc. are operated based on detection signals from a shape detector placed on the exit side of the rolling mill, and the shape in the strip width direction is feedback-controlled. What you have to do is go and hit. At this time, the control computer expresses the plate shape using a mathematical model and calculates the manipulated variable. The mathematical model is generally expressed as a power series, the coefficients of which are determined based on the signal from the shape detector.

In the technique disclosed in JP-A-54-151066, the following 4th power series y=λ1x is used as the above mathematical model.
+λ2X2+E,x3+λaX'-(+) is adopted. Here, y is the elongation rate of the plate (tension difference,
or the steepness is also substantially the same), λ1~
λ4 is a constant determined based on the signal from the shape detector, and X is a distance from the center of the width of the plate toward the edge of the plate, and is a normalized variable.

Then, it is proposed to divide the above equation (1) into an asymmetrical component y,=λIX+λ x3 and further use it as a shape evaluation parameter.

Further, Japanese Patent Application Laid-Open No. 55-4214:1 discloses a technique for controlling the shape of a plate by operating a roll bender, a roll shift, etc. based on the above four shape evaluation parameters.

(Problems to be Solved by the Invention) Generally, the shape distribution detected by a shape detector during normal rolling shows a pattern as shown in FIG. 1 (a) (in the case of edge elongation). However, when rolling a wide material after rolling a narrow material, or when rolling to the final stand by shifting the work rolls in the previous stage in tandem rolling to reduce the edge drop,
As shown in FIG. 1(B), a large defect in the shape of the ear wave may occur at the end of the plate.

In the conventional shape control described above, the operation amount of roll bender, roll shift, etc. is determined using all the data of the steepness distribution λ in the sheet width direction. Further, detection of the plate shape is performed by sampling several points to several tens of points in the width direction of the plate.

Therefore, if a large ear wave shape defect occurs,
The shape evaluation parameters were largely influenced by these ear waves, resulting in the estimation of a plate shape different from the actual plate shape. As a result, the accuracy of shape control became low, and even if shape control was performed using a roll bender or the like, shape defects occurred.

SUMMARY OF THE INVENTION Therefore, the present invention aims to provide a shape control method in sheet rolling that can obtain a sheet with a good shape over the entire width of the sheet even if a large defect in the shape of the corrugation occurs at the edge of the sheet.

(Means for Solving the Problems) The shape control method in plate rolling according to the first invention detects the plate shape on the exit side of the rolling mill, and calculates Find the steepness distribution in the plate width direction expressed by the following equation. Next, two shape evaluation parameters that display the symmetric component with respect to the center of the plate width from the steepness distribution (the difference between the steepness at the edge of the plate and the steepness at the center of the plate, and the extreme value of the steepness in the symmetrical component) are calculated. difference from the steepness of the central part of the board),
Two parameters that indicate the asymmetric component (the difference between the steepness at the edge of the plate and the steepness at the center of the plate, and the difference between the extreme value of the steepness in the asymmetric component and the steepness at the center of the plate), and the plate A shape evaluation parameter (difference between the detected plate edge steepness and the plate edge steepness determined from the steepness distribution) is obtained based on the detected value of the edge. Then, the operation amount of the shape control means is adjusted according to these shape evaluation parameters.

The shape of the plate on the exit side of the rolling mill is detected as the distribution of steepness, elongation, or tension difference in the width direction of the plate at regular intervals (for example, 0.2 to 0.5 sec) in the longitudinal direction of the plate. Since the steepness, elongation rate, and tension difference all give substantially the same plate shape, in the following description, the plate shape will be expressed by the steepness. As a shape detector,
Split roll type, deflection type, and other conventional detectors can be used.

The quartic expression representing the steepness distribution in the board width direction is determined based on the shape detection values excluding the board edge detection values, as described above. The quartic equation can be found by determining the coefficients of each term, but
Each coefficient is calculated by the control computer based on the detected value of the shape. Here, the range of the board end portion is a narrow range L extending from the board side end toward the center of the board width as shown in FIG. 2, that is, a range where large ear waves are generated. In addition, the plate edge shape evaluation parameters are the detected plate edge steepness and the plate edge (point e in Figure 2) or the boundary of the plate edge near the center of the plate (
The difference between the value of the steepness distribution at a point located inside the plate edge e by 1 in FIG. 2 may be used.

As shape control means one or a combination of a work roll bender, an intermediate roll bender, a work roll shifter, an intermediate roll shifter and a coolant supply device are used.

The shape control method in plate rolling according to the second invention is characterized in that the work roll bender adjusting at least one of force, intermediate roll bender force, and intermediate roll shift amount.

In addition, according to the two shape evaluation parameters that indicate an asymmetrical component with respect to the center of the sheet width, the rolling position difference (difference between the rolling blade on the drive side and the rolling blade on the work side), the work roll bender force difference, and the intermediate roll bender force At least one of the difference and the intermediate roll shift amount difference is adjusted. Then, the distribution of the coolant supply amount in the roll axis direction is adjusted in accordance with the shape evaluation parameter determined based on the detected value of the front plate end.

The shape control method in plate rolling according to the third invention adjusts at least one of the work roll bender force, the intermediate roll bender force, and the intermediate roll shift amount obtained in the same manner as the second invention, and also adjusts the rolling position. At least one of the difference, the work roll bender force difference, the intermediate roll bender force difference, and the intermediate roll shift amount difference is adjusted. According to the shape evaluation parameter determined based on the detected value of the plate end, the roll profile has a roll profile such that at least a roll gap near the roll end widens toward the roll end, and is movable in the roll axis direction. Adjust the amount of work roll shift.

(Function) As described above, the quartic equation representing the steepness distribution in the board width direction is determined based on the shape detection values excluding the board edge detection values. Therefore, the plate shape expressed by the quartic equation is
The plate shape as a whole is close to the actual shape without being affected by the large ear waves generated at the edge of the plate. Furthermore, since the plate shape is expressed using the detected values only for the edge portion of the plate, a plate shape that is close to the actual shape can be obtained.

As described above, the amount of operation of the roll bender and the like is determined based on the plate shape expressed in a shape close to the actual shape, and the roll bender etc. are adjusted based on this, so that the shape of the plate can be controlled with high precision.

(Example) The shape control of the plate is roughly performed in the following steps.

First, the plate shape is detected on the exit side of the rolling mill, and based on the detected value, the plate shape is expressed by a quartic equation, and shape evaluation parameters are determined from this. Then, based on the deviation between the target shape evaluation parameter and the shape evaluation parameter determined above, the operation amount of the roll bender, etc. is calculated according to the control law. The calculation results are output to a roll bender, etc., and the plate shape is feedback-controlled. The processing of the detected value of the plate shape to the calculation of the manipulated variable is performed by the control computer as usual.

FIG. 2 shows an example of the steepness distribution λ in the sheet width direction according to the present invention.

As shown in the drawing, the steepness distribution λ in the board width direction is approximated by λ=α+βX+γx2+δx3+ex' using the detected values excluding the detected values in a narrow fixed range 2 at the end of the board. Here, X is a distance from the center C of the plate width as the origin toward the edge of the plate, and α to ε are coefficients determined by the shape detection values. Further, in the figure, b represents 1/2 of the board width, λ6 represents the detected value at the end of the board, and 9 represents the 2nd or 4th position of the board, respectively.

Similarly to the conventional method, equation (5) is divided into the asymmetric component λ-=βX+δx3 r-and then, by the symmetric component and the asymmetric component,
Next shape evaluation parameter symmetric component Δ2=λ+(b)-in+(0) or A4=λ or (b/J″r)-in or (0) asymmetric component Δ
Find 1=λ-(b)-in-(0) or. In addition, as a shape evaluation parameter, the plate end Δ6=λ6−
λ(b) or Δ6=λ6-λ(b-i)...(
Find 9). Note that if the asymmetric component is small, Δ6
=λ6−λ+(b) or Δ6=λ6−λ or (b−Il) − (10).

When the shape evaluation parameter Δ is determined as described above, based on the deviation ΔΔ from the target shape evaluation parameter Δrer,
Generally, the amount of operation correction (for example, the amount of correction of work roll bender force and the amount of correction of intermediate roll shift amount) ΔY is determined by equation (11).

ΔY=A ・ΔΔ ・−(
11) Here, A is a matrix representing the control law. The control law A can be determined in advance by experimenting with an actual machine or by numerical analysis.

FIG. 3 shows an example of a cold rolling mill in which the present invention is implemented.

The cold rolling mill 5 is a six-layer rolling mill consisting of a work roll 6, an intermediate roll 7, and a backup roll 8. The work roll 6 has a tapered portion 6a at the end of the roll body, and is movable in the roll axis direction by a work roll shift 12. The shape control means includes a rolling down device 1O, a work roll bender 11, a work roll shift 12, an intermediate roll bender 13, an intermediate roll shift 14, and a coolant supply device 16. A shape detector 18 is arranged on the exit side of the cold rolling mill 5 to measure the shape of the rolled plate 1. As the shape detector 18, a split roll type detector, a deflection type detector, or an ordinary detector can be used. Furthermore, the cold rolling mill 5 has a control computer and a controller (
(none of which are shown).

The coolant supply device 6 has a control valve 23 attached to each nozzle 22, as shown in FIG. 4(a).

With this coolant supply device]6, the supply of roll coolant can be adjusted for each nozzle 22, so the work roll 6
Thermal crowns are made by strongly cooling only the required areas.
Therefore, the plate 1 can be controlled into a desired shape.

In the coolant supply device 17 shown in FIG. 4(B), a large number of nozzles 22 are attached to a header 25 via control valves 23, and a pair of partitions 26 are slidably inserted into the header 25. ing. header 25
A low-temperature coolant supply pipe 28 is connected to the center of the system, and a high-temperature coolant supply pipe 29 is connected to both ends of the system. Adjust to obtain the desired thermal crown.

FIG. 5 is a block diagram of the control system of the rolling mill. In this embodiment, the symmetrical component of the plate shape is controlled by the work roll bender force Fw, and the asymmetrical component is controlled by the rolling position difference ΔP. Furthermore, the shape of the plate end is controlled by the roll coolant Q.

Roll bender system uses roll bender control law ε8・BS
, a control element based on the characteristic GD of the steady-state deviation compensator, and a control element based on the characteristic GII of the roll bender. Here, BS is an influence coefficient expressed by the following equation (12), and ε8 is a tuning rate.

Roll coolant system uses control law ε for roll coolant.・
It consists of control elements according to Bo. Here, Bo is the influence coefficient and ε. is the tuning rate. The rolling load system consists of control elements including the influence coefficient AP. These influence coefficients BS, B.

and AP can be determined in advance through experiments on an actual machine or through numerical analysis.

Further, the characteristics of the detector, regulator, and output device in the above block diagram are as follows.

Shape detector: Roll bender system: Steady-state deviation compensator: Based on the deviation between the target plate shape Δref and the detected plate shape Δ, the amount of correction of the work roll bender force by the roll bender control law Bs and the tuning rate ε8 ΔF is determined. Then, the roll bender force correction amount ΔF is output to the work roll bender after passing through a steady-state deviation compensator. Further, the roll coolant control law B0 and the tuning rate ε are determined based on the shape deviation. The correction amount ΔQ of the roll coolant is determined by this.

Note that the shape Δ of the rolled plate is determined by four elements: work roll bender force Fw, rolling load P, roll coolant Q, and entry side plate crown C4. The influence coefficient As that the work roll bender force F8 and the roll coolant Q have on the shape of the rolled plate, and the influence coefficient AC that the entrance plate crown CH has on the shape of the rolled plate are both unique to the rolling mill. , does not necessarily have to be clear when controlling the plate shape.

FIG. 6 is a block diagram showing another example of the control system. In this embodiment, the symmetrical component of the plate shape is controlled by the intermediate roll bender force F, and the asymmetrical component is controlled by the work roll bender force difference ΔFw. Further, the shape of the plate end portion is controlled by the work roll shift position difference ΔS.

Note that the control elements are the same as those of the control system shown in FIG.

Here, a specific example of the plate shape obtained by the method of this example will be described.

The rolling equipment was a 6-stand tandem cold rolling mill, and the plate shape was measured on the exit side of the 6th stand. Shape control was performed using the control system shown in FIG. The specifications and rolling conditions of the rolling stand are as follows.

Work roll diameter: 335non Body length: 1422mm Intermediate roll diameter: 594+nm Body length: 1457mm Backup roll diameter: 1152mm Body length: 1520m111 plate size (narrow width material); plate thickness 2.3mm-+0.15mm
, Plate width 100100 O wide material): Plate thickness 2.7mm → 0.3mm, Plate width 12
00mff1 Rolling rate: 33t → 31t Front of tension crab 6 kg/mm2. When using the conventional method under the above conditions of 12 kg/mm2 at the rear, severe elongation occurred and rolling became impossible. On the other hand, according to the method of the present invention, the above-mentioned medium elongation was completely eliminated, and a good plate shape was obtained.

(Effects of the Invention) According to the present invention, the operating amounts of the roll bender and other parts are determined based on a mathematical model that represents a plate shape close to the actual shape, and the roll bender and the like are adjusted based on this, so that a good plate shape can be obtained. Therefore, it is possible to improve the yield and productivity in plate rolling.

[Brief explanation of the drawing]

Fig. 1 shows a steepness distribution curve representing an example of the plate shape based on the detection value of a shape detector, Fig. 2 shows a steepness distribution curve expressed by an approximate formula in this invention, and Fig. 3 shows a steepness distribution curve according to the present invention. This shows an example of a cold rolling mill to be implemented, and FIG. 4 is a schematic perspective view of the rolling mill, FIG. 4 is an explanatory diagram of a coolant supply device used in the present invention, and FIGS. It is a block diagram of a control system, showing an embodiment. 1.-Rolled plate material, 6.. Work roll, 6a.- Taper part, 7.. Intermediate roll, 8-. Backup roll, 10-. Rolling device, 11-. Work roll bender, 12- - Work roll shift, 13- Intermediate roll bender, l 4-... Intermediate roll shift, 16.1
7- Coolant supply device, l 8-... Plate shape detector,
22--nozzle, 23--control valve, 25--header, 26--partition, 28.29--coolant supply pipe.

Claims (3)

[Claims] (1) Detect the plate shape on the exit side of the rolling mill, calculate the steepness distribution in the plate width direction expressed by a quartic equation based on the detected shape value,
Two shape evaluation parameters that display the symmetrical component with respect to the center of the board width from the steepness distribution (the difference between the steepness at the end of the board and the steepness at the center of the board, and the extreme value of the steepness in the symmetric component and the center of the board) Two parameters displaying the asymmetric component (the difference between the steepness at the edge of the plate and the steepness at the center of the plate, and the extreme value of the steepness in the asymmetric component and the steepness at the center of the plate). In the method of controlling the plate shape by adjusting the operation amount of the shape control means according to these shape evaluation parameters, the steepness distribution is obtained excluding the detected value at the edge of the plate, and this steepness The four shape evaluation parameters obtained based on the above-mentioned steepness distribution and the shape evaluation parameters obtained based on the detected value of the plate edge (detected plate edge steepness and plate edge steepness obtained from the steepness distribution) A shape control method in plate rolling, characterized in that the amount of operation of the shape control means is adjusted according to the difference between the shape and the shape of the shape. (2) Detect the plate shape on the exit side of the rolling mill, calculate the steepness distribution in the plate width direction expressed by a quartic equation based on the detected shape value,
Two shape evaluation parameters that display the symmetrical component with respect to the center of the board width from the steepness distribution (the difference between the steepness at the end of the board and the steepness at the center of the board, and the extreme value of the steepness in the symmetric component and the center of the board) Two parameters displaying the asymmetric component (the difference between the steepness at the edge of the plate and the steepness at the center of the plate, and the extreme value of the steepness in the asymmetric component and the steepness at the center of the plate). In the method of controlling the plate shape by adjusting the operation amount of the shape control means based on these shape evaluation parameters, the steepness distribution is determined by excluding the detected value at the plate edge, and At least one of the work roll bender force, the intermediate roll bender force, and the intermediate roll shift amount is adjusted according to the two shape evaluation parameters that indicate a symmetrical component with respect to the center of the sheet width determined from the steepness distribution, and the sheet width is adjusted. Displaying components that are asymmetric about the center 2
At least one of the rolling position difference, work roll bender force difference, intermediate roll bender force difference, and intermediate roll shift amount difference is adjusted according to the shape evaluation parameters, and the shape is determined based on the detected value of the plate end. A shape control method in plate rolling characterized by adjusting the distribution of coolant supply amount in the roll axis direction according to an evaluation parameter (difference between the detected plate edge steepness and the plate edge steepness determined from the steepness distribution) . (3) Detect the plate shape on the exit side of the rolling mill, calculate the steepness distribution in the plate width direction expressed by a quartic equation based on the detected shape value,
Two shape evaluation parameters that display the symmetrical component with respect to the center of the board width from the steepness distribution (the difference between the steepness at the end of the board and the steepness at the center of the board, and the extreme value of the steepness in the symmetric component and the center of the board) Two parameters displaying the asymmetric component (the difference between the steepness at the edge of the plate and the steepness at the center of the plate, and the extreme value of the steepness in the asymmetric component and the steepness at the center of the plate). In the method of controlling the plate shape by adjusting the operation amount of the shape control means based on these shape evaluation parameters, the steepness distribution is determined by excluding the detected value at the plate edge, and At least one of the work roll bender force, the intermediate roll bender force, and the intermediate roll shift amount is adjusted according to the two shape evaluation parameters that indicate a symmetrical component with respect to the center of the sheet width determined from the steepness distribution, and the sheet width is adjusted. Displaying components that are asymmetric about the center 2
At least one of the rolling position difference, work roll bender force difference, intermediate roll bender force difference, and intermediate roll shift amount difference is adjusted according to the shape evaluation parameters, and the shape is determined based on the detected value of the plate end. According to the evaluation parameter (difference between the detected plate edge steepness and the plate edge steepness determined from the steepness distribution), a roll profile is created such that at least the roll gap near the roll edge widens toward the roll edge. 1. A shape control method in plate rolling, which comprises adjusting the shift amount of a work roll which is movable in the axial direction of the roll.