JP3743253B2 - Elongation rate control method of temper rolling mill - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an elongation rate control method for a temper rolling mill in which bridle rolls are provided on the entry side and the exit side, and particularly suitable for use in temper rolling a cold-rolled steel strip. The present invention relates to an elongation rate control method for a temper rolling mill capable of accurately controlling an elongation rate even when passing through a welding point or changing an elongation rate.
[0002]
[Prior art]
For the elongation rate control in rolling with a temper rolling mill for metal strips such as cold rolled steel sheets, a rolling control method that makes the tension at the bridle rolls usually provided on the entry side and the exit side of the temper rolling mill constant and There is a tension control method in which the rolling load of the temper rolling mill is constant, and a method for controlling the elongation rate by the speed difference between the front and rear bridle rolls is known. For example, in JP-A-4-305305, when the elongation rate is within the set range, the tension is kept constant while the elongation rate is controlled by the rolling load of the temper rolling mill, and when the elongation rate is out of the set range, rolling is performed. It describes that the elongation rate is controlled by changing the speed of the bridle rolls on the entry side and the exit side while keeping the load constant.
[0003]
[Problems to be solved by the invention]
In the elongation rate control in the conventional rolling of the metal strip, calculation is performed in consideration of the deformation resistance and friction coefficient of the strip that changes with changes in the rolling speed, and the bridle roll speed with respect to the deviation from the target elongation rate. It is effective when the rolling speed is constant, and is effective when the rolling speed is constant. Therefore, there was a problem that the elongation rate control accuracy was lowered.
[0004]
The present invention has been made to solve the above-mentioned conventional problems, and can control the elongation with high accuracy even when accelerating / decelerating, passing through the welding point, or changing the elongation, and achieves stable elongation control. The task is to do.
[0005]
[Means for Solving the Problems]
The present invention relates to an elongation rate control method for a temper rolling mill in which bridle rolls are provided on the entry side and the exit side, respectively, and the elongation rate after rolling or a deviation from the target value is within a set range. When the tension is kept constant and the elongation rate is controlled by the rolling load of the temper rolling mill, the elongation rate , or when the deviation from the target value is outside the set range, the temper rolling The target rolling load of the machine is changed in accordance with the deviation from the target value of the elongation rate, and the elongation rate is controlled by changing the speed of the bridle roll to solve the above problem.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0007]
FIG. 1 shows an embodiment of a control device for carrying out the present invention. In FIG. 1, the strip 6 is fed into the temper rolling mill 3 by the entry-side bridle roll 1 and is fed by the exit-side bridle roll 2. In the meantime, the reduction by the temper rolling mill 3, the tension between the entry side bridle roll 1 and the temper rolling mill 3, and the tension between the temper rolling mill 3 and the exit side bridle roll 2, Is stretched by.
[0008]
Reference numerals 7 and 8 denote driving motors for the bridle rolls 1 and 2 on the entry side and the exit side, respectively, and are controlled via the bridle roll control devices 13 and 14 and the speed controllers 17 and 18, respectively. A speed setter 28 outputs a set speed to these control systems.
[0009]
Reference numerals 4 and 5 denote tension detectors respectively installed on the entry side and the exit side of the temper rolling mill 3 and detect the tension generated in the strip 6. Reference numerals 11 and 12 denote pulse generators for detecting the rotational speeds of the bridle rolls 1 and 2 on the entry side and the exit side. The outputs of the pulse generators 11 and 12 are taken into an elongation rate calculator 21 to calculate the elongation rate of the strip 6. The elongation rate controller 22 is, for example, a proportional and integral control element controller. From the elongation rate setting value (target value) ε11 by the elongation rate setting unit 33, the measured elongation rate value ε10 of the strip by the elongation rate calculator 21 is used. The control signal ΔP11 is output according to the deviation signal Δε obtained by subtracting.
[0010]
When the elongation deviation Δε is within the set range, the control signal (rolling load change) ΔP11 from the elongation controller 22 is added to the signal (target rolling load) P11 of the rolling load setter 34. The actual rolling load measured value P10 by the load cell 29 is subtracted from the obtained new target rolling load P12, and this value is set as a target value by the rolling reduction control device 16 of the temper rolling mill 3 via the hydraulic reduction servo pump 10. The hydraulic cylinder 36 is driven to perform elongation rate control by rolling load.
[0011]
On the other hand, when the elongation deviation is out of the set range, the target rolling load is changed. The load is changed using the control gain calculation circuit 40.
[0012]
As shown in FIG. 2, the control gain calculation circuit 40 multiplies the load change amount ΔP11 output from the elongation rate controller 22 by a certain ratio when calculating the load change amount using the elongation rate deviation Δε. In addition, a control gain K including a ramp generator (gradual slope given to alleviate the step change) is calculated.
[0013]
The new target rolling load P12 is calculated by the following equation.
[0014]
P12 = P11 + K · ΔP11
[0015]
In this way, the target rolling load is changed and the speed of the bridle rolls 1 and 2 is changed to perform the elongation rate control. In this case, the elongation rate control on / off logic circuit 23 according to the speed has the elongation rate deviation Δε. Exceeds the upper limit value Δε2 (or −Δε2), the elongation rate control is started until the intermediate value Δε1 (or −Δε1) at which the control is stopped and then stopped. Based on the control signal ΔP11 of 22, the speed control output ΔV11 is output to the control gain calculation circuits 24 and 25. The control gain calculation circuits 24 and 25 calculate the control gain of the output ΔV11 in order to determine the speed correction values ΔV12 and ΔV13 of the input side and output side bridle rolls 1 and 2, respectively.
[0016]
The entry side tension controller 26 is composed of, for example, a proportional and integral control element, and receives an output signal obtained by subtracting the output T10 of the entry side tension detector 4 from the output T11 of the entry side tension setter 31 and inputs a tension control signal. Output to the speed controller 17 of the incoming bridle roll 1. On the exit side, the exit side tension controller 27 and the exit side tension setting unit 32 have the same functions as those on the entry side.
[0017]
In order to further improve the accuracy, the deviation from the target elongation ε11 takes into account the elongation obtained by the speed difference between the inlet and outlet bridle rolls 1 and 2 and the strip deformation resistance and friction coefficient that change with the rolling speed change. A rolling load ΔP11 to be changed with respect to Δε is obtained. By calculating the sum of the target rolling load P11 and K · ΔP11 (K is a gain) and setting it as a new target rolling load P12, fluctuations in elongation rate during acceleration / deceleration and when the welding point and the rolling condition change point pass through the rolling mill , And stable elongation rate control becomes possible.
[0018]
In this way, as shown in FIG. 3, it was confirmed that the elongation rate converged to the target value with high accuracy in a short time by changing the load command value in accordance with the variation of the elongation rate.
[0019]
In the embodiment described above, the case where there is one temper rolling mill and the entry side and exit side bridle rolls are individually driven has been described as an example. Even when there are a plurality of units, the present invention can be carried out even when the entry-side and exit-side bridle rolls are mechanically connected by a planetary gear mechanism. Further, the rolling object is not limited to the cold rolled steel sheet.
[0020]
【The invention's effect】
According to the present invention, stable elongation rate control can be achieved by reducing the variation in elongation rate during acceleration / deceleration or when passing through a rolling mill at welding points and changing rolling conditions. Therefore, it is possible to easily produce a product having a target elongation rate on a rolling line or a skin pass line by performing high-precision elongation rate control, thereby improving production efficiency and reducing costs.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of a control device for carrying out the present invention. FIG. 2 is a detailed diagram of a control gain arithmetic circuit 40 used in the embodiment. FIG. 3 is a control example according to the present invention. Time chart showing the description [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 2 ... Bridle roll 3 ... Temper rolling mill 13, 14 ... Bridle roll control apparatus 21 ... Elongation rate calculator 22 ... Elongation rate controller 24, 25, 40 ... Control gain calculating circuit 33 ... Elongation rate setting device 34 ... Rolling load setting device

Claims (1)

In the elongation control method of the temper rolling mill in which bridle rolls are arranged on the entry side and the exit side,
When the elongation after rolling or the deviation from the target value is within the set range, the elongation is controlled by the rolling load of the temper rolling mill with a constant tension,
When the elongation rate or the deviation from the target value is out of the set range, the target rolling load of the temper rolling mill is changed according to the deviation from the target value of the elongation rate, and the bridle An elongation rate control method for a temper rolling mill, wherein the elongation rate is controlled by changing a roll speed.

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