JPH05337530A - Looper controlling method - Google Patents

Abstract

PURPOSE:To prevent the generation of tention and loosing of a steel strip at the time of starting a looper and to prevent the generation of abuses such as necking of width of the steel strip between tandem rolling machines. CONSTITUTION:An amount of loosing of the steel strip 3 is calculated from the time required for rolling from the time of biting the steel strip by an upstream side rolling machine to the time of biting the steel strip by a downstream side rolling machine, the controlling angle of the looper is calculated from the obtained value, the angle of the looper 4 which is started up when the strip is bitten by the downstream side rolling machine is contin-ously detected and the speed of the looper is reduced when the angle of the looper 4 becomes a specified angle which is equal or larger than the controlling angle of the looper.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION This method is used in a tandem rolling mill by suppressing over tension of a strip generated at the time of starting the looper in a looper device provided between a rolling mill upstream and downstream of a tandem rolling mill. The present invention relates to a looper control method for preventing necking of a steel strip width between machines.

[0002]

2. Description of the Related Art A looper is provided between a rolling mill (stand) and a rolling mill (stand) of a tandem rolling mill, and is started when a steel strip (material to be rolled) is caught in a downstream stand. Then, ascent is started, and after the steel strip comes into contact with the steel strip, an appropriate tension is applied to the steel strip while detecting the loop amount between the rolling mills of the steel strip. FIG. 1 is a graph showing the relationship between the looper angle, the looper motor starting current, and the tension of the steel strip when the looper is started. As shown in FIG. 1, when the looper is started, it is necessary to increase the looper angle at a quick start (high rising speed), promptly follow the steel strip, adjust the loop amount, and give an appropriate tension. On the other hand, when in contact with the steel strip (hereinafter referred to as "metal touch"), the looper motor start-up current (hereinafter referred to as "looper current") is reduced so that the impact is reduced, and the looper rising speed is controlled to be reduced. It is necessary to

When the mass flow record of the looper has an error with respect to the predicted value before the plate is caught, the timing at which the looper contacts the steel strip changes. As a result, as shown in FIG. 2, when the loop amount of the steel strip between the rolling mills is smaller than the desired amount, the metal touch is performed when the rising speed (angular acceleration) of the looper is large, and the steel strip is momentarily touched. Too much tension is applied to the looper, the looper is hit, the tension fluctuates unstablely, necking of the material occurs, and the thickness and width of the sheet decrease. On the other hand, as shown in FIG. 3, when the loop amount of the steel strip between the rolling mills is larger than the desired amount, it takes longer for the looper to contact the steel strip, and the steel strip is given a predetermined tension. Since this is not possible, the plate width increases.

Since the looper starting speed control is performed by a looper current control system that is patterned so that overtension can be suppressed to the maximum when the loop amount reaches a predetermined value, a predetermined loop amount is set. If it comes off, there is no adaptive control method. Conventionally, the following methods have been already known as means for preventing fluctuations in the tension of a steel strip due to a mass flow setting error when the plate is bitten. How to reduce the inertial weight of the looper
"Prior art 1"). It is equipped with a means for detecting the tension of the steel strip, that is, a tension at the moment when the looper contacts the steel strip, and a means for detecting the ascending speed of the looper, and controls the looper based on the above detection value (the above is referred to as “Prior Art 2”). ")).

[0005]

However, it is not possible to completely prevent the fluctuation of the tension of the material due to the mass flow setting error at the time of biting the plate only by the means of the above-mentioned prior arts 1 and 2.

As a soft touch control method for the looper,
The following technology is proposed in Japanese Patent Laid-Open No. 62-179,806. The position of the plate (steel strip) is measured by the position detector when starting the looper after passing the plate, and the actual position of the plate and the position of the looper are compared, and the ascending speed of the looper is calculated according to the deviation. (Hereinafter, referred to as “Prior Art 3”).

However, the prior art 3 has the following problems. FIG. 6 is a schematic view showing a rolling mill and a steel strip. As shown in FIG. 6, since the apex position of the loop of the steel strip 3 formed between the rolling mills 1 changes depending on the speed and plate thickness, it is difficult to accurately grasp the loop amount.
It is necessary to install a plurality of position sensors 2 between rolling mills and further approximate the loop shape with a function based on the obtained data to obtain the loop length.

Therefore, an object of the present invention is to suppress the tension and loosening of the steel strip generated at the time of start-up thereof and to appropriately perform looper start-up control, thereby necking the width of steel strip between tandem rolling mills. An object of the present invention is to provide a looper control method capable of preventing the adverse effects of the above.

[0009]

The present invention provides a looper control method for controlling the tension of a steel strip by raising a looper provided between an upstream side rolling mill and a downstream side rolling mill by a predetermined angle. The loop amount of the steel strip is calculated from the time from the biting of the upstream rolling mill to the biting of the downstream rolling mill, the looper control angle is calculated from the calculated value, and then the steel strip is rolled downstream. It is characterized in that the angle of the looper activated from the time when the machine is bitten is continuously detected, and the rising speed of the looper is reduced when the angle of the looper becomes a predetermined angle equal to or larger than the looper control angle. It is a thing.

[0010]

[Function] When the looper is started, the loop amount of the material between rolling mills is estimated to detect the loop amount from the mass flow record of the looper, and the looper control angle at the start is determined from the detected value. From, it controls the looper starting current to control the looper rising speed.

Next, the present invention will be described with reference to the drawings. FIG. 4 is a flowchart showing one embodiment of the present invention. The flow of loop amount control is as follows. When the control of the looper starting current for controlling the looper rising speed is started, the load relay signal (steel strip rolling mill biting signal) of the (i-1) stand (upstream side stand) is turned on (in Fig. 4). 2 blocks). next,
The movement of the steel strip turns on the load relay signal of the i stand (downstream stand) (3 blocks in Fig. 4). When the looper rises (when the looper starts rising)
The looper current of is set to a current value A (4 blocks in FIG. 4). The looper current value A is the first highest peak A, as shown in the graph showing the looper starting current pattern in FIG. Simultaneously with applying the looper current (starting the looper) and turning on the i stand load relay signal, the loop amount is calculated, and the looper control angle (target angle for metal touch) is determined from the calculated value (Fig. 4). 5 blocks inside). The larger the looper control angle, the higher the looper control angle. After giving the looper current value A and starting the rise of the looper, the angle of the looper is continuously detected (the actual result of the looper angle is checked), and when the looper angle reaches a certain angle equal to or larger than the looper control angle (Fig. (6 blocks in 4) and lower the looper current to change to the current value B shown in FIG. 5 (7 blocks in FIG. 4). Then, when a metal touch is detected by the tensiometer (or by calculation) (8 blocks in FIG. 4), the current value C shown in FIG. 5 is changed to normal current control (9 blocks in FIG. 4).

As described above, by changing the looper starting current flexibly, the fluctuation of the tension when the looper comes into contact with the steel strip is suppressed to the minimum. In FIG. 5, the current value A, the current value B, and the current value C are as follows. A is the table setting value. B is a looper starting current required to support the looper's own weight and the steel strip's own weight at the control angle θ ₀ . _{Here, B = F B (W S} , W G, θ 0). C is a looper starting current for generating the tension T _S per unit area at the control angle θ ₀ . _{Here, C = B + F C (} T S, θ 0).

The loop amount of the looper can be calculated by one of the following methods. Loop amount calculation method by load relay signal (L / R signal). If the time (time difference) between the load relay signal on between the upstream stand {(i-1) stand} and the downstream stand {(i) stand} is t, the loop amount is as shown in (1) below.
Equation 1 is obtained.

[0014]

[Equation 1]

However, v _R : rolling roll peripheral speed f: advanced rate F: function. And, the looper control angle θ ₀ is as follows (2)
Since it is an equation, it is obtained by back-calculating from equation (2). θ ₀ = F (L _i ) ─ (2).

A loop amount calculation method by detecting the speed of a steel strip. The detected value of the speed of the steel strip
Assuming V _i−1 , the loop amount is given by Equation (2) below.

[0017]

[Equation 2]

However, V : Speed detection value of steel strip. Then, the looper control angle θ ₀ is as follows (4)
Since it is an equation, it is calculated by back-calculating from equation (4). θ ₀ = F ₀ (L _i ) ─ (4).

The explanation of the function of
Shown in Equations 4 and 5. FIG. 7 is a schematic view showing an arrangement of loopers and steel strips between rolling mills. In FIG. 7, 1a is an i rolling mill, 1b is an (i + 1) rolling mill, 3 is a steel strip,
4 is a looper. L: center distance between rolling mills l _x : distance between upstream rolling mill and looper rotary shaft l _r : distance between looper rotary shaft and looper roller l _G : distance between looper rotary shaft and looper center of gravity W _S : steel between rolling mills Strip weight W _L : Looper weight η _L : Looper reduction ratio Φ: Looper motor torque coefficient.

[0020]

[Equation 3]

[0021]

[Equation 4]

[0022]

[Equation 5]

[0023]

As described above, according to the present invention, it is possible to suppress the tension and looseness of the steel strip generated at the time of starting, and to perform the proper looper control, and to prevent the tandem rolling mills from being operated. Industrially useful effects that can prevent adverse effects such as necking of the steel strip width are provided.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the looper angle, the looper starting current, and the tension of the steel strip when the looper is started.

FIG. 2 is a graph showing the relationship between the looper angle, looper starting current, and steel strip tension when the looper is started.

FIG. 3 is a graph showing the relationship between the looper angle, the looper starting current, and the tension of the steel strip when the looper is started.

FIG. 4 is a flowchart showing an embodiment of the present invention.

FIG. 5 is a graph showing a looper starting current pattern.

FIG. 6 is a schematic view showing a rolling mill and a steel strip.

FIG. 7 is a schematic view showing a rolling mill, a looper, and a steel strip.

[Explanation of symbols]

 1 rolling mill 2 position sensor 3 steel strip 4 looper.

Claims (1)

[Claims] 1. A looper control method for controlling the tension of a steel strip by raising a looper provided between an upstream side rolling mill and a downstream rolling mill by a predetermined angle, the method comprising: The loop amount of the steel strip is calculated from the time until the biting on the downstream side rolling mill, and the looper control angle is calculated from the calculated value.
Next, the angle of the looper activated from the time when the steel strip is bitten by the downstream rolling mill is continuously detected, and the rising speed of the looper when the angle of the looper becomes a predetermined angle equal to or larger than the looper control angle. A looper control method, characterized in that: