JP2581139B2 - Rolling method of plate material and rolling device thereof - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet rolling method for controlling a rolling shape of a sheet by a rolling mill having a shape correcting mechanism, and a rolling apparatus therefor.

[Conventional technology]

FIG. 2 is a conceptual diagram of the plate shape of a plate material rolled by a conventional rolling mill, and FIG. 3 is an enlarged sectional view of a corrugated portion of the plate material shown in FIG. If the elongation of (21) is not uniform in the width direction, the wavy portion (2
2) occurs, and if the flat portion (23) undulates by a height m above the predetermined length l, the undulating portion (22) extends to l ', and the steepness λ of the wave is m / l and has the following relationship:

FIG. 4 is also a conceptual view of a sheet crown, in which a work roll (24) in contact with a sheet material (21) and a backup roll (25) in contact with the work roll (24) are obtained by rolling the sheet material (21). Then, a bending phenomenon occurs due to the reaction force of the plate material (21), and a crown such as the bending curves (24a) and (25a) occurs.

In the drawing, the hatched portion a is the two rolls (24), (25)
The contact elastic strain approach amount of the work roll (2)
4) Elastic flatness due to contact between plate material (21).

On the other hand, a shape control method for presetting a rolling force in order to obtain a target plate shape is disclosed in, for example, Japanese Patent Publication No. 52-15253. According to this, the calculation formula of the roll bending force for keeping the elongation rate in the plate width direction that determines the plate shape is theoretically investigated to derive a relational expression, thereby determining the bending force.

That is, this shape control method calculates the roll bending force as a function of the sheet width, the average rolling load per unit width, the work roll crown and the entry side sheet crown, and calculates the roll bending force as a preset value of the roll bending force. The bending force is corrected on the basis of a deviation between the average rolling load and a similar average rolling load obtained by actual measurement.

[Problems to be solved by the invention]

In the conventional method for controlling the shape of a sheet material, the roll bending force for keeping the elongation rate in the sheet width direction constant was derived from a calculation formula and determined. Is not taken into account,
There were problems such as that the preset pattern of the roll bending force that was always feasible was not always available.

In addition, each steelmaker is still struggling to clarify this theoretical formula, and there is a problem that it is not easy to find it.

The present invention has been made in order to solve such a problem, and calculates a preset value of a realistic operation amount of a shape correcting device, and obtains a shape control method of a plate material that can obtain a proper plate crown and a good plate shape. The purpose is to do so.

[Means for solving the problem]

The method for rolling a sheet material according to the present invention includes a method for controlling a rolling shape of the sheet material by controlling an operation amount of a shape correcting mechanism provided in each rolling mill to correct the shape of the sheet material. A step of calculating a crown influence coefficient and a shape influence coefficient of the sheet material at each rolling mill exit side based on the crown influence coefficient and the shape influence coefficient, and empirically based on the shape of the sheet material between the rolling mills. The maximum value and the minimum value of the crown of the plate at the exit side of each rolling mill are determined by the upper limit value and the lower limit value of the operation amount of each of the shape correction mechanisms input for the calculation so that the shape of the plate material becomes good. Calculating, and comparing the maximum value and the minimum value of the crown with the target crown, and when the target crown is equal to or greater than the minimum value and equal to or less than the maximum value, the shape repair based on the target crown. Comprising the step of calculating a preset value mechanism operation amount, based on the preset value by controlling the amount of operation of each of the shape correction mechanism controls the rolling shape of the plate material.

Further, the step of calculating the preset value includes selecting a lower limit value as an operation amount of each shape correcting mechanism when the target crown is larger than the maximum value, or selecting each of the shape correcting mechanisms when the target crown is smaller than the minimum value. The upper limit value is selected as the operation amount of.

Still further, the plate rolling apparatus according to the present invention is a plate rolling apparatus that controls the rolling shape of the plate by controlling an operation amount of a shape correcting mechanism provided in each rolling mill to correct the shape of the plate, A schedule calculation device that calculates the crown influence coefficient and the shape influence coefficient of the sheet material at each rolling mill exit side based on the schedule calculation, and the shape of the sheet material is empirically based on the shape of the sheet material between the rolling mills. A control amount constraint input device for inputting an upper limit value and a lower limit value of an operation amount of the shape correcting mechanism for calculation to be good;
A maximum / minimum crown calculating device for calculating the maximum and minimum values of the crown of the sheet material on the exit side of each rolling mill based on the crown influence coefficient and the shape influence coefficient, and the upper limit value and the lower limit value. Comparing a minimum value with a target crown, and when the target crown is equal to or greater than the minimum value and equal to or less than the maximum value, a preset calculation device that calculates a preset value of an operation amount of each of the shape correcting mechanisms based on the target crown; and The preset value is corrected based on the difference between the actual crown and shape and the calculated crown and shape obtained based on the preset value, and the operation amount of each of the shape correcting mechanisms is controlled based on the corrected value. To control the rolled shape of the sheet material.

[Action]

The present invention provides a generally known plate crown model,
Based on the plate shape model, the model can be applied to the model by inputting the upper and lower limit values for the operation amount of the shape correction device based on the shape of the plate material in the intermediate rolling mill, which is difficult to recognize in the model, for calculation. The maximum value and the minimum value of the crown at each rolling mill exit side are calculated, the crown obtained by the calculation is compared with the target crown, and the operation amount of each shape correcting device is determined according to the comparison result.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.
In FIG. 1, A is a rolling mill having a work roll bending device, and here shows a case of a four-high rolling mill having a roll bending device as a shape correcting mechanism. In the drawing, (1) is a plate material, (2) is a work roll directly pressed against the plate material (1), (3) is a backup roll that contacts and reinforces the work roll (2),
(4) a roll bending force setting device, (5) a shape detector of the plate material (1), (6) a crown detector, (7)
Is a schedule calculator for calculating schedules such as sheet thickness, rolling force, tension, and rolling speed, and (8) is a crown calculator based on information from the schedule calculator (7).
The crown for calculating the influence coefficient of the plate shape, the shape influence coefficient calculation device, and (9) are the upper and lower limit values of the operation amount of the roll bending device (that is, the shape correction mechanism) so that each stand plate shape becomes good on the passing plate. The upper and lower limits of the operation amount are values determined based on experience so that the operator can determine the shape of the plate member (1) of the intermediate stand and improve the shape. It is a value that becomes a shape.)
A control amount constraint input device for the operator to input,
(10) is calculated by the crown and shape influence coefficient calculating device (8) and is based on the coefficient output from the device (8) and the upper and lower limit values output from the control amount constraint input device (9). The maximum and minimum crown calculators for calculating the maximum and minimum values of the plate crown of each stand (rolling mill), (11) is the maximum output from the maximum and minimum crown calculator (10),
Minimum and target crown (preset)
And (12) is a correction calculation device for correcting the preset value by the preset value calculation device (11).

Next, the principle of operation will be described, and then the operation of the embodiment will be described.

First, the basic plate crown C _i and shape ε _i are as follows. Here, the subscript _i means the _i- th stand.

Equation (1) is an equation relating to the plate crown, (2) is an expression relating to the plate shape, and in the expression (1), ▲ α ⁱ _P ▼ and αα ⁱ _{F
^{▼, ▲ α i CW ▼,}} ▲ α i CB ▼, ▲ α i C ▼ respective rolling load (P _i), roll bending force (F _i), the work roll crown (R _CWi), the backup roll crown (R _CBi ) Is a work roll axis deflection influence coefficient and a crown inheritance coefficient. In the equation (2), h is a plate thickness, and ξ and ζ are coefficients relating to the shape.

Each of the influence coefficients is obtained, for example, from the dynamic equation of the equation (3) regarding the bending of the roll.

x: Roll axis direction coordinate y: Roll axis bending amount E: Roll longitudinal elastic modulus I: Roll cross section moment P _F : Load per unit length in the width direction G: Roll lateral elastic coefficient A: Roll cross sectional area P (X): Rolling load distribution in the roll axis direction To solve the equation (3), the load distribution P (x) and the boundary condition may be given.

Further, in rolling, since the roll expands due to heat and affects the crown shape, it is necessary to determine the thermal crown by the following equation (4) and consider R _CW and R _CB .

Here, beta: linear expansion coefficient sigma: Poisson's ratio r: radial distance T (r): radial temperature distribution u _r: is a roll radial displacement.

In addition, T (r) is the following basic formula of heat conduction for a cylinder. In, the boundary condition on the surface of a cylinder or the like is given.

Thus (1), (2) expression of R _CWi, R _CBi, (from Equation 4) P _{i ^{is, α P i, α F i}} , α CW i, α CB i, α C i is (3 type) ,
The rolling load P _i is known from the output of the schedule calculation device 7, and if the roll bending force F _i is given, C _i and ε _i can be obtained.

Next, if the upper and lower limits of the roll bending force for improving the shape between stands are input by the operator, substitute the values into the equation (1) using the values F _i ^max and F _i ^min. Then, the minimum and maximum crown of each stand can be obtained. That is, when determining the maximum crown substitutes F _i ^min in equation (1), Motomari is C _i ^max, the C _i ^max and F _{i + 1}
^By substituting ^min similarly, Ci _{+ 1} ^max is obtained. When this process is repeated to the last stand, the maximum crown C _N ^max is obtained (N is the last stand number).

Conversely, calculation using F _i ^max in the same manner as above yields C _N ^min .

In this way, the crown control range is determined and C _N ^min C
_{If AIM} C _N ^max (where C _AIM is the target crown), there is a combination of each stand roll bending force that satisfies the target crown, so C _N ^min C _AIM or C _N ^max C _AIM
In the case of, when the threading property is good, the combination of the stand roll bending force and the F _i closest to C _AIM , that is, C _N ^min
C _AIM If F _i ^max, it would be best to preset C _N ^max C _AIM if F _i ^min.

If C _N ^min C _AIM C _N ^max , the combination of the stand roll bending forces is determined as in the following equation (6).

ΔC = C _AIM −C _N ^min ... (6) Set C _N = C _{AIM The} roll bending force is F _i ^C and F _i ^max
And ΔF _i = F _i ^C −F _i ^max = a (F _i ^max −F _i ^min ), the relational expression of the following expression (7) is obtained by solving the expression (1).

Next Becomes

Therefore, each stand roll bending where C _N = C _AIM is as follows: F _i ^C = F _i ^max + a (F _i ^max −F _i ^min ) (10) Here, −1a0 is apparent, and F _i is always required. ^min F
_i ^C F _i ^max is satisfied.

Incidentally but is not necessarily the ε _{N =} ε _AIM, especially since in the final stand is that it is known better shape than the crown is sensitive to the control amount, F _N
Fine adjustment of ^C should be good, and the crown amount due to this correction amount is almost negligible.
Therefore when the final stand shape by F _I ^C and epsilon ^C, epsilon
_{N =} epsilon is F _N ^C of the correction amount [Delta] F ^epsilon for the _AIM Therefore, the final roll bending force preset value is obtained as follows.

iN−1 F _i ^C = F _i ^max + a (F _i ^max −F _i ^min ) (12) i = N F _i ^C = F _i ^max + a (F _i ^max −F _i ^min ) + ΔF ^ε. 13) Second, the estimated values are not without error, and this error may not achieve the target crown and shape.
In order to improve the accuracy of the estimated value, a correction function is required in Bar to Bar. As a correction method, the plate shape is made good in the final stand, and the other stands are operated so as to become the target plate crown and reflected in the determination of the control amount of the next material.

Therefore, ΔF _i ^C = G _i ^C · (C _AIM −C _ACT) ) (14) (where iN−1) ΔF ^{ε ′} = G ^ε · (ε _AIM −ε _ACT ) (15) (12) Reflect the following equation to (13).

F _i ^C ′ = F _i ^C + ΔF _i ^C (iN−1) (16) F _i ^{C ′} = F _i ^C + ΔF ^{ε ′} (i = N) (17) where G _i ^C and G ^ε is an adjustment coefficient for operation, C
_ACT and ε _ACT are crown detector (6) and shape detector (5)
The actual crown and shape obtained from. Equation (16),
Since F _i ^C ′ calculated by the expression (17) does not always satisfy the control amount constraint, if the upper limit or the lower limit is applied at the time of presetting, the value is replaced with that value and preset.

Next, the shape control of the above embodiment will be described with reference to FIG.

First, the schedule calculator (7) calculates the sheet thickness, rolling force,
The schedule calculation such as the rolling speed is performed, and the crown and the shape influence coefficient are calculated by the crown and shape influence coefficient calculating device (8) based on this information. This factor,
The upper and lower limits of the amount of operation of the roll bending device by the input of the operator are set. The results transmitted from the control amount constraint input device (9) are used as the maximum and minimum crown calculation devices (10) to obtain the maximum and minimum values of each stand. The value crown is obtained by calculation, and the preset value of the operation amount of the work roll bending device is calculated by the preset value calculating device (11) by comparing the preset value with the previously set target crown as described above. This preset value is output to the roll bending force setting device (4) to change the roll bending,
The work roll (2) is controlled. This control operation is performed at the time of presetting. When the plate material (1) is passed, the plate shape and the crown actual value are sent to the correction arithmetic unit (12) by the shape detector (5) and the crown detector (6), An error from the target is calculated, a correction amount is determined based on the difference, and the preset value is corrected by the preset value calculation device (11) to control the roll bending force setting device (4).

〔The invention's effect〕

The method for rolling a sheet material according to the present invention includes a method for controlling a rolling shape of the sheet material by controlling an operation amount of a shape correcting mechanism provided in each rolling mill to correct the shape of the sheet material. A step of calculating a crown influence coefficient and a shape influence coefficient of the sheet material at each rolling mill exit side based on the crown influence coefficient and the shape influence coefficient, and empirically based on the shape of the sheet material between the rolling mills. The maximum value and the minimum value of the crown of the plate at the exit side of each rolling mill are determined by the upper limit value and the lower limit value of the operation amount of each of the shape correction mechanisms input for the calculation so that the shape of the plate material becomes good. Calculating, and comparing the maximum value and the minimum value of the crown with the target crown, and when the target crown is equal to or greater than the minimum value and equal to or less than the maximum value, the shape repair based on the target crown. The method includes a step of calculating a preset value of the operation amount of the mechanism, and controls the operation amount of each of the shape correcting mechanisms based on the preset value to control the rolling shape of the plate material. Thus, it is possible to obtain a proper crown and a plate material having a good shape.

Further, the step of calculating the preset value includes selecting a lower limit value as an operation amount of each shape correcting mechanism when the target crown is larger than the maximum value, or selecting each of the shape correcting mechanisms when the target crown is smaller than the minimum value. Since the upper limit value is selected as the operation amount of, the operation amount of each shape correction device that can always be realized can be easily obtained.

Still further, the plate rolling apparatus according to the present invention is a plate rolling apparatus that controls the rolling shape of the plate by controlling an operation amount of a shape correcting mechanism provided in each rolling mill to correct the shape of the plate, A schedule calculation device that calculates the crown influence coefficient and the shape influence coefficient of the sheet material at each rolling mill exit side based on the schedule calculation, and the shape of the sheet material is empirically based on the shape of the sheet material between the rolling mills. A control amount constraint input device for inputting an upper limit value and a lower limit value of an operation amount of the shape correcting mechanism for calculation to be good;
A maximum / minimum crown calculating device for calculating the maximum and minimum values of the crown of the sheet material on the exit side of each rolling mill based on the crown influence coefficient and the shape influence coefficient, and the upper limit value and the lower limit value. Comparing a minimum value with a target crown, and when the target crown is equal to or greater than the minimum value and equal to or less than the maximum value, a preset calculation device that calculates a preset value of an operation amount of each of the shape correcting mechanisms based on the target crown; and The preset value is corrected based on the difference between the actual crown and shape and the calculated crown and shape obtained based on the preset value, and the operation amount of each of the shape correcting mechanisms is controlled based on the corrected value. Since the rolling shape of the plate material is controlled by the correction arithmetic device, the operation amount of each shape correcting device can be easily obtained, and a more appropriate crown and a better shape can be obtained. It can be obtained sheet.

[Brief description of the drawings]

FIG. 1 is a block connection diagram showing a method of rolling a sheet material according to an embodiment of the present invention, FIG. 2 is a conceptual view of a sheet shape by conventional rolling, FIG. 3 is an enlarged sectional view of FIG. 2, and FIG. FIG. 3 is a conceptual diagram of a conventional plate crown. In the figure, (1) is a plate material, (2) is a work roll, (3) is a backup roll, (4) is a roll bending force setting device, (5) is a shape detector, (6) is a crown detector,
(7) is a schedule calculation device, (8) is a crown and shape influence coefficient calculation device, (9) is a control amount constraint input device,
(10) is a maximum and minimum crown calculation device, (11) is a preset value calculation device, and (12) is a correction calculation device. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (3)

(57) [Claims] 1. A sheet rolling method for controlling a rolling shape of a sheet material by controlling an operation amount of a shape correcting mechanism provided in each rolling mill for correcting the shape of the sheet material, the method comprising the steps of: A step of calculating a crown influence coefficient and a shape influence coefficient of the sheet material on the machine exit side, and the crown influence coefficient and the shape influence coefficient, and the shape of the sheet material is empirically based on the shape of the sheet material between the rolling mills. Calculating the maximum value and the minimum value of the crown of the plate material at each rolling mill exit side by using the upper limit value and the lower limit value of the operation amount of each of the shape correction mechanisms input for calculation to be good, and Comparing the maximum value and the minimum value of the crown with the target crown, and when the target crown is equal to or more than the minimum value and equal to or less than the maximum value, the amount of operation of each of the shape correcting mechanisms based on the target crown. Comprising the step of calculating a set value, the rolling method of the plate for controlling a rolling shape of the sheet by controlling the amount of operation of each shape correction mechanism based on the preset value. 2. The step of calculating a preset value includes selecting a lower limit value as an operation amount of each shape correcting mechanism when the target crown is larger than the maximum value, or selecting the lower limit value when the target crown is smaller than the minimum value. 2. The method according to claim 1, wherein an upper limit is selected as an operation amount of the shape correcting mechanism. 3. A sheet rolling apparatus for controlling a rolling shape of said sheet material by controlling an operation amount of a shape correcting mechanism provided in each rolling mill for correcting the shape of the sheet material. A schedule calculation device for calculating a crown influence coefficient and a shape influence coefficient of the sheet material on the machine-out side; and an empirical calculation based on the shape of the sheet material between the rolling mills so that the shape of the sheet material is good. The control amount constraint input device for inputting the upper limit value and the lower limit value of the operation amount of the shape correcting mechanism, the crown influence coefficient and the shape influence coefficient, and the upper limit value and the lower limit value of the sheet material at each rolling mill exit side. A maximum / minimum crown calculating device for calculating the maximum and minimum values of the crown; comparing the maximum and minimum values of the crown with a target crown, wherein the target crown is greater than or equal to the minimum value and the maximum When the value is equal to or less than the target crown, a preset calculation device that calculates a preset value of the operation amount of each of the shape correction mechanisms based on the target crown, and an actual crown, a calculated crown obtained based on the shape and the preset value, A plate rolling apparatus comprising: a correction operation device that corrects the preset value based on a difference from a shape and controls an operation amount of each of the shape correction mechanisms based on the correction value, and controls a rolling shape of the plate material.