JPS6111125B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rolling roll control method for a high-tension skin pass rolling mill, and in particular, a method for controlling rolling rolls in a high-tension skin-pass rolling mill, which takes into account factors that change depending on line speed changes and enables more appropriate elongation control. Concerning a roll control method.

Generally, a high tension skin pass rolling mill is comprised of two sets of bridles and a rolling roll disposed between the bridles. In such a temper rolling mill, both bridles are controlled with a speed difference in order to keep the elongation rate of the steel strip constant, but the rolling rolls are controlled at different speeds due to the high tension between the bridles. The elastically deformed steel strip is plastically deformed, and torque control is performed to maintain a constant elongation between the bridles.

Conventionally, torque control for the rolling rolls of a high-tension temper rolling mill has been performed by controlling the armature current of a rolling roll driving motor to be constant.
The specific principle of this rolling roll control method is as follows. That is, Fig. 1 shows the tension distribution of a high-tension temper rolling mill, and as shown in this figure, the tension generated in the steel strip 1 is between the entry bridle 2 and the rolling roll 3, and between the rolling roll 3 and the exit bridle. There are 4 different types. Here, the front tension T of the rolling roll 3
If the torque of the rolling roll electric motor is controlled so that the rear tension T _B is _F , the required power P
_MF is expressed by the following formula.

P _MF = (T _F −T _B )×v _M /6120×η(KW)…(1
) However, v _M is rolling roll speed (m/min), η
is the overall efficiency.

On the other hand, since the rolling roll 3 is performing rolling,
The power P _MO required for rolling is as follows.

P _MO =t×w×σ _yp ×v _M ×p/100/6120×
η (KW)...(2) where t is the steel strip thickness (mm), w is the steel strip width (mm), σyp is the deformation resistance (Kg/mm ² ), and p is the rolling reduction (%).

For these reasons, the electric motor control of the rolling roll 3 must maintain constant tension across the rolling roll 3 and control the power required for rolling. When the motor output is P (KW), it becomes as follows.

P=P _MF +P _MO =K・E _c・I _a (KW)
...(3) However, K is a proportionality constant, E _c is the motor back electromotive voltage V, and I _a is the motor armature current A.

Such electric motor output P is proportional to the mill roll speed (v _M ∝K・E _c・I _a ), and from this, conventional mill roll control is based on the back electromotive force E _c
(V) is controlled to generate a voltage proportional to the line speed (roll speed v _M ), which is made possible by keeping one factor, the armature current I _a (A), constant. For this reason, conventionally, a constant elongation rate is obtained by setting a current corresponding to the required rolling torque and giving a control command to the electric motor to keep the current constant at the set value.

However, in the conventional method described above, even if the armature current I _a is simply controlled to be constant in order to control the elongation rate to a constant value, there are factors that change as the line speed changes, so the steel strip It has the disadvantage that the elongation rate cannot be kept constant. That is, the deformation resistance σyp (Kg/mm ² ) shown in equation (2) changes depending on the rolling speed, and the deformation resistance σyp (Kg/mm ² )
is, σ _yp = σa + e ^6.5 (〓ε/〓ε ₀ ) ^kT/0.14 …(4) σ _a = e ^4.3 (ε+0.019) ^0.242 σ ₀ =10 ¹¹ However, σ _a is the standard deformation resistance at room temperature (Kg/ mm ² ), 〓ε
is the strain rate (%), and ε ₀ is the strain rate (%/
sec), k is a constant, and T is the temperature (〓).

As can be understood from the above equation (4), the deformation resistance σ _yp changes depending on the strain rate ε ₀ , which means that the deformation resistance σ _yp changes as the rolling speed changes. As a result, as mentioned above, in armature current control that focuses only on the tension applied to the steel strip 1, the output P fluctuates, and the rear tension T _B of the rolling roll 3 changes, making it impossible to obtain a predetermined elongation rate. becomes impossible.

It is also known that mill mechanical loss changes depending on the speed, and if this mechanical loss is not taken into consideration, problems similar to those mentioned above will occur, such as differences in elongation rate due to fluctuations in line speed. This results in drawbacks.

The present invention focuses on the problems caused by the conventional control method for rolling rolls, and takes into account factors that change depending on the line speed in torque control to obtain a predetermined elongation rate, and controls the elongation rate depending on the line speed. It is an object of the present invention to provide a rolling roll control method for a high tension temper rolling mill that does not fluctuate.

In order to achieve the above object, the rolling roll control method for a high tension temper rolling mill according to the present invention detects the rolling roll speed, and applies a tension corresponding to the necessary rolling torque as a control current to the rolling roll driving electric motor. In addition to setting the current, the set current value is corrected by determining the current to be compensated from the deformation resistance and mechanical loss as a speed function, and the rolling roll is controlled by this correction current. This is to prevent fluctuations in growth rate due to changes.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 shows a control system diagram of the rolling roll according to this embodiment. The high-tension temper rolling mill is configured to convey a steel strip 1 to be passed from an input bridle 2 to an output bridle 4 via a rolling roll 3. In such a temper rolling mill, the rolling roll 3 is driven by an electric motor 5, and the electric motor 5 is controlled by changing the set value of the armature current. The control system for this rolling roll 3 is provided with a current setting device 6 for setting the current to be applied to the electric motor 5. The current I a determined by the above equation (3), that _is , the current value corresponding to the required rolling torque is input to this current setting device 6.
The output value is inputted to the speed regulator 7 and directly inputted to the current regulator 8. The speed regulator 7 has a feedback path from the back electromotive voltage detector 9;
A feedback path from a line speed detector 10 provided on the exit bridle 4 is connected, and the line speed and back electromotive force are controlled to be proportional. On the other hand, the control current is used to control the drive of the electric motor 5 from the current regulator 8 via the power converter 11. A feedback path from a current detector 12 is connected to this current regulator 8, and control is performed to keep the armature current constant.

In this way, the motor 5 is controlled and driven so that the armature current becomes the set value.
In this embodiment, in addition to the above configuration, a compensation circuit is provided. That is, a speed detector 13 is provided to detect the speed of the rolling roll,
A correction calculator 14 into which the detection signal of the speed detector 13 is input is connected to an adder 15 interposed between the current setter 6 and the speed regulator 7. In this correction calculator 14, the speed of the rolling roll 3 is inputted, as well as the amounts set by the deformation resistance standard setting device 16 and the mechanical loss setting device 17. Therefore, the deformation resistance and mechanical loss that change depending on the speed are calculated and output in the correction calculator 14 as a function of the speed.

This allows the armature current to be appropriately compensated for deformation resistance and mechanical loss that vary with speed.
The rolling rolls can be optimally controlled.

In this way, according to this embodiment, rather than simply applying the tension current to the armature as a set value,
By calculating the current value corresponding to the deformation resistance and mechanical loss that change as the speed changes during operation, and adding this calculated compensation current to the set current, an appropriately corrected current is applied to the armature. It turns out. Therefore, regardless of changes in speed, the temper rolling mill can maintain a constant elongation rate.

In particular, in this embodiment, the armature current is divided into a tension component current, a deformation resistance component current, and a mechanical loss component current, and the current to be controlled can be appropriately adjusted according to speed changes, so that torque control can be performed optimally. This makes it possible to perform control to properly maintain a constant elongation rate.

As explained above, according to the present invention, the elongation rate of the steel strip can be maintained constant, and the function of adjustment rolling can be improved.

[Brief explanation of the drawing]

Figure 1 is a tension distribution diagram of a high tension temper rolling mill, Figure 2
The figure is a control system diagram of this embodiment. DESCRIPTION OF SYMBOLS 1... Steel strip, 2... Entry side bridle, 3... Roll, 4... Output side bridle, 5... Electric motor, 13... Speed detector, 14... Correction calculator,
15...Adder, 16...Deformation resistance standard setter,
17...Mechanical loss setting device.

Claims (1)

[Claims] 1 For the rolling rolls disposed between the entry and exit bridles that apply high tension to the steel strip,
In a rolling roll control method for a high tension temper rolling mill that controls the elongation rate by setting a current corresponding to the required rolling torque, the rolling roll speed is detected and the deformation resistance of the material changes due to speed changes and the machine The method comprises calculating the deformation resistance and compensating current corresponding to the mechanical loss, correcting the current setting value, and controlling the elongation rate by applying the corrected current to the rolling roll. Roll control method for tension temper rolling mill.