JPS63268506A - Rolling method for multistage rolling mill - Google Patents

Abstract

PURPOSE:To improve the accuracy of the shape and plate thickness of products by optimally controlling a crown at the time of low speed of an initial stage of rolling and estimating the optimal controlling value of the crown, then performing the rolling through a gauge meter AGC. CONSTITUTION:A multistage rolling mill 1 equipped with work rolls 2 intermediate rolls 3, 4 and split backup rolls 5 is provided and a shape detector 6 and a thickness gauge 7 are arranged. Further, the proper numbers of a pushing means 8 are disposed behind the rolls 5. Signals from the shape detector 6 are inputted into a shape control computing element 9 to control the pushing means 8 and intermediate rolls 3 through the computing element 9. At the time of low speed on the initial stage, the shape control is performed by using both shifting of the rolls 3 and the crown controlling. At the time of succeeding high speed, the AGC control is performed by fixing the estimated crown control value. In this way, both accuracy of the shape and plate thickness are improved simultaneously.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a rolling method using a multi-high rolling mill that performs automatic shape control during rolling of a thin plate using, for example, a 12-high or 20-high rolling mill.

(Prior Art) In recent years, multi-high rolling mills with high shape control capabilities have come to be used in rolling thin plates of copper alloys and the like in order to meet the demand for high shape accuracy. However, in such multi-high rolling mills, shape control in thin plate rolling is complicated due to high control capability, and the conventionally known plate shape control method for HC mills or 6-high rolling mills (Japanese Patent Laid-Open No. 54-15
No. 1066, No. 55-19401, No. 55-4214
Publication No. 4) is not useful.

In addition, in multi-high rolling mills, the plate shape is controlled by pushing split backup rolls (crown adjustment), intermediate roll bending (or intermediate roll shifting), etc., but it has not been possible to control both at the same time. This is the current situation.

In other words, in order to obtain a good plate shape, it is desirable to control the shape using both of the above methods, but especially when the crown adjustment is changed, not only the plate shape but also the average plate thickness will change, and the plate thickness in the longitudinal direction will change. Accuracy deteriorates.

Figure 10 shows an example of the relationship between the amount of crown adjustment and the amount of plate thickness change, and it is approximately L7μ for crown adjustment 1i10.3am.
This shows that a change in plate thickness has occurred.

In this way, complex compound elongation occurs, so
Improvement of the plate shape by simultaneous control of both methods has not yet been achieved.

Furthermore, when gauge meter AGC, which is generally used as a plate thickness control method, is adopted, variations in rolling load due to changes in crown adjustment amount may act in a direction that further deteriorates plate thickness accuracy. There's a problem.

(Object of the Invention) The present invention has been made in view of the above-mentioned conventional circumstances, and its purpose is to achieve good automatic plate shape control in consideration of the characteristics of a multi-high rolling mill, that is, to improve shape accuracy and plate thickness accuracy. It is an object of the present invention to provide a rolling method using a multi-high rolling mill that makes it possible to satisfy both requirements.

(Structure of the Invention) In order to achieve the above object, the present invention includes an intermediate roll that is movable in the axial direction, and a roll that is divided into a plurality of rolls in the axial direction, and that is arbitrarily perpendicular to the axial direction for each divided section. When rolling using a multi-high rolling mill equipped with a backup roll that enables pushing in a certain direction, the intermediate roll position and crown adjustment amount are controlled to optimal values at low speed in the early stage of rolling, and then at high speed in a constant speed state. After predicting the optimum crown adjustment amount and moving the crown adjustment amount to this predicted value and fixing it, the gauge meter AGC was turned on and rolling was started.

(Example) Next, an example of a rolling method using a multi-high rolling mill according to the present invention will be described with reference to the drawings.

FIG. 1 shows a 20-high rolling mill, which is an example of a multi-high rolling mill to which the rolling method according to the present invention is applied. The first intermediate roll 3, the second intermediate roll 4, and the split type backup roll 5 are provided, and a shape detector 6. and plate thickness gauge 7 are provided.

Further, as shown in FIG. 2, in the upper half of the roll group, an appropriate number, for example, three pushing means 8 are provided behind the backup roll 5, and the backup roll 5 is It is formed so that it can be pushed into the work roll 2 side by an appropriate amount. The amount of pushing by these three pushing means 8 (hereinafter referred to as the amount of crown adjustment)
Let them be X+, Xt, and Xs, respectively. Further, the first intermediate roll 3 is a Taber roll, and is shiftable in its axial direction. Let this shift amount be x4.

Here, the shape detector 6 is a collection of sensors, and this sensor directly measures the tension of the rolled material 1, and calculates the relative elongation value from the difference from the tension at the horizontal position, for example, the center of the sheet width. This is a known method.

Furthermore, a shape control calculator 9 and an AGC (automatic plate thickness control) calculator IO are provided. And then ＼
The signal from the shape detector 6 is input to the shape control calculator 9 into which the rolling schedule has been input in advance as detailed below.
The pushing means 8, which is an actuator, from the shape control calculator 9. A control signal for the shift drive means for the first intermediate roll 3 is output. Further, a signal from the plate thickness gauge 7 and a signal regarding the actual crown adjustment amount are inputted to the AGC calculator 10 to control the pushing means 8.

Next, the rolling method according to the present invention will be explained according to a flowchart showing a control procedure in FIG.

First, when rolling is started, the rolling speed is initially in a low speed state, so in the first step (#l), shape control is performed using both the first intermediate roll shift and crown adjustment.

As already disclosed in Japanese Patent Application No. 61-60359 by the applicant of the present application, an example of this shape control is as follows.

First, on the basis of the signal output from the shape detector 6, a shape evaluation function χ to correspond to a value for evaluating the shape of the rolled material 1 is defined as follows.

However, f'%: measured elongation value by the i-th sensor rf: target elongation value W+ for the i-th sensor: shape weighting coefficient n for the i-th sensor: number of effective sensors (3 in this example) Moreover, the elongation values of rr and rf are expressed as relative elongation values with the elongation value at the center of the plate width as 0, and the rolled material within the plate width among the sensors of the entire shape detector 6! Only the effective sensor values within this board width, which are in direct contact with the board, are considered. As a result, the output of the effective sensor can be reflected in the shape evaluation without approximating it, and by considering Wi, the shape at the i-th position can be weighted within the board width.

Note that the value of Wi is determined by the product specifications. For example, in the case of a product that does not allow ear waves, setting the Wi value for the edge sensor to be larger than the value at the center of the board width will prevent ear waves from occurring. If you do the opposite, control will be applied to prevent mid-length elongation.

Next, the relationship between the control variables and the output of the sensor 8 will be explained.

In the case of this embodiment, the control variables are the pushing amount X + + X t + X 3 of the backup roll 5 and the shift mX+ of the first intermediate roll 3, where, for example, the direction of the arrow in FIG. 2 is positive. Further, the number of effective sensors of the shape detector 6 is set to 3, for example, and the output is f? +fL gate. Then, each of the control variables xl * ”” + X 4 is independently d
Changing x+, .

In other words, the outputs fL~, ■ (however, f:=o> change due to changes in each of the control variables 11+, ~+X4).

Note that the solid lines in FIGS. 4 to 7 indicate the state before the change, and the broken lines indicate the state after the change, and only the changed control variables are shown.

From the above, the output f of each sensor? , ~, fg is a function of the control variable Xl + ~ +
Output f for ++~+X4? , ~, r8 can be approximated by a linear term of control variables Xl+~+X4 if the changes are simple.

In the case of a multi-high rolling mill as in this embodiment, the work rolls have a small diameter, so the output of the sensor in response to a change in one control variable is not simple. Therefore, the output of the i-th sensor is defined by a quadratic expression of control variables as follows.

(i-1-n) (2) However, it is a calculated value of the rHsi-th sensor output, which means how many percent has increased as a relative elongation rate, and is usually expressed in units of 1 unit.

ai: The push amount of the backup roll and the shift amount of the first intermediate roll are set to a certain standard (the value of the control variable xj, j=l~ffi when this standard state is achieved is O.)
The output value of the i-th sensor when

bij: influence coefficient of on the control variable for the i-th sensor.

eBk: Control variables xj and Kk for the i-th sensor
mutual influence coefficient.

1: Control amount by all actuators number of roses (in this example, three roses) , Cup-up roll push amount, That is, the control variables xl, ~+X3 and one The shift amount of the intermediate roll, i.e. control variable X4).

This bij, cijk is the automatic data collection shown later,
Automatically calculated from data obtained during rolling by sorting,
Find it by making corrections or by calculation.

Next, the following equation is approximated by setting Δfi to be the change in the sensor output fi when the control variable Xj is changed by ΔXj.

Therefore, when the control variable Xj is changed by ΔXj, that is, when the position of the actuator is changed by ΔXj, the expected value of the measured r'i becomes [lj+Δri. As a result, the expected value χ+Δχ of the shape evaluation function χ is expressed by the following equation.

χ1Δχ=(Σ(f1+Δr, -ΔIi door・W,”
) l/2i=1 xk)・Δxj)・W: ko1/2
(4) Optimizing the plate shape of the rolled material l means minimizing the shape evaluation function χ, so the optimal control amount Δxj must satisfy the following equation.

Specifically, this formula is as follows.

'``i'''' (bil!+ΣcII2-xk)-
(6) k=1 (ρ=1 to m) Then, by solving this equation, the optimum control amount ΔX3 can be obtained, and this ΔXj is calculated by the amount of change in the actuator.

However, since this ΔX is obtained by an approximate solution method, the actuator control ff1xj is actually optimized by repeating this operation several times.

FIG. 8 shows the entire control system of the above device to which this control method is applied, and each job is divided into tasks 1 to 3.
Task 1, which is the main task, inputs the rolling schedule, and then inputs the sensor output, rolling load, back-up roll push value, first intermediate roll shift value, and plate thickness.

It reads the tension, etc., writes it to the log data file, and at the same time sends the data to the multi-sensor nonlinear control device. In task 2, the multi-sensor nonlinear control device that has received this data performs the above-mentioned control while referring to the influence coefficient and mutual influence coefficient. Once rolling is completed, task 3, which is a data organization task while referring to log data, is an influence coefficient.

Update the mutual influence coefficient.

FIG. 9 is a time chart of the above control.

Note that when presetting the crown adjustment before rolling, the optimum value differs depending on the crown of the rolling material plate on the entry side and the deformation resistance, so if the crown adjustment is preset in a negative manner, the optimum value cannot be obtained.

Therefore, it is necessary to find the optimum value for each rolled material. In addition, the influence coefficient used for control can be learned and modified at low speeds.

In the second step #2), as the rolling speed increases and becomes a constant speed state, the optimum crown adjustment amount at high speed in the constant speed state is predicted.

That is, at high speeds, a heat crown occurs on the roll and the shape changes, so the amount of heat crown is determined by calculation or experiment and introduced into the control equation. For example, according to the control method in the first step (#l) described above, the shape is expressed as f1.

However, cj is the heat crown distribution of the work roll.The method for determining the optimum value is the same as the control method above.
''- In the third step (#3), the crown adjustment amount is corrected to the optimal value at steady speed, and at this time, since the shape will deteriorate if only the crown adjustment amount is moved, the first intermediate roll is adjusted according to the crown adjustment amount. Optimize from position.

In the fourth step (#4), the gauge meter AGC is turned on to start automatic control of the plate thickness.

In the fifth step (#5), the amount of crown adjustment is fixed, and shape control is performed only by shifting the first intermediate roll, and this continues until the end of rolling.

This shape control is performed, for example, in the first step (#I) described above.
In the control method in , this can be performed by keeping the crown adjustment amount constant and constantly calculating only the first intermediate roll shift amount.

In the above embodiment, the method described in Japanese Patent Application No. 61-60359 was applied, but the present invention is not limited thereto.

(Effects of the Invention) As is clear from the above description, according to the present invention, the intermediate roll is movable in the axial direction, and the intermediate roll is divided into a plurality of sides in the axial direction, and each divided section is provided with an arbitrary color. When rolling using a multi-high rolling mill equipped with a backup roll that allows pushing in a direction perpendicular to the axial direction, after controlling the intermediate slot position and crown adjustment amount to optimal values at low speed in the early stage of rolling, The optimal crown adjustment amount at high speed in a constant speed state is predicted, and after the crown adjustment amount is moved to this predicted value and fixed, the gauge meter AGC is turned on and rolling is performed.

For this reason, the gauge meter AGC is off at low speeds (
By moving the crown adjustment in a state where the plate thickness accuracy is not emphasized, deterioration of the plate thickness accuracy in the longitudinal direction can be prevented.

In addition, when presetting the amount of crown adjustment in advance, it is not possible to take into account the entrance side crown of the plate material or variations in deformation resistance. However, by optimally controlling the amount of crown adjustment at the initial low speed, optimization according to the plate material can be achieved. This has the effect of making it possible to

[Brief explanation of drawings]

Fig. 1 is a block diagram of a 20-high rolling mill to which the method according to the present invention is applied, Fig. 2 is a partial cross-sectional front view showing a group of rolls above the rolled material in Fig. 1, and Fig. 3 is a block diagram of a 20-high rolling mill to which the method according to the present invention is applied. FIGS. 4 to 7 are diagrams showing the relationship between control variables and sensor outputs. FIG. 8 is a configuration diagram showing an example of a control system implementing the present invention. FIG. is a time chart, and FIG. 10 is a diagram showing the relationship between the amount of crown adjustment and the amount of plate thickness change. 3... First intermediate roll, 5... Backup roll, 8- Pushing means. Patent applicant: Agent of Kobe Steel, Ltd.
Patent Attorneys: Blue and White, 2 people Fig. 2 WJ3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 1-12
1g10 1(: (F 10 (OfOfO
fo 10L> Ka Muni Ward

Claims (1)

[Claims] (1) Multistage having an intermediate roll that is movable in the axial direction and a backup roll that is divided into a plurality of rolls in the axial direction and can be pushed in any direction perpendicular to the axial direction for each divided section. When rolling using a rolling mill, the intermediate roll position and crown adjustment amount are controlled to optimal values at low speed in the early stage of rolling, then the optimal crown adjustment amount at high speed in a constant speed state is predicted, and the crown adjustment is performed to this predicted value. A method of rolling using a multi-high rolling mill, characterized in that after moving and fixing the amount, rolling is carried out with a gauge meter AGC turned on.