JPH0659486B2 - Rolling equipment control method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a rolling mill control method, and more particularly to a rolling mill control method in which upper and lower roll speeds are different from each other.

[Conventional technology]

As a new rolling method that is effective for rolling ultra-thin plates and difficult-to-work materials, and reducing the rolling force for the purpose of energy saving in the rolling of metal sheets, it is possible to perform rolling by rotating the upper and lower work rolls at different peripheral speeds. A fast rolling method has been proposed.

Further, even in the case of constant speed rolling, a different speed rolling state occurs due to wear of the upper and lower rolls, thermal expansion and a difference in roll diameter.

Various proposals have been made for controlling the rotation speed of the upper and lower rolls to a predetermined peripheral speed ratio (see, for example, JP-A-59-229223).
issue). In rolling, it is important for stable operation that the neutral points of the upper and lower rolls are within the rolling contact arc.

In the conventional control, since it is premised on constant velocity rolling, the neutral points of the upper and lower rolls are considered to be the same point, and deviation to the entrance side of the rolling contact arc cannot occur after passing the strip. Therefore, by monitoring the advance rate, it can be determined whether the neutral point deviates to the exit side of the rolling contact arc. As a control that considers the neutral position, it is known that the plate speed signal and the work roll signal are measured to calculate the neutral position, and the neutral position is set to a specific position under the maximum torque constraint. There is also a known example in which the method of approaching is used (Japanese Patent Publication No. 58-42761).

[Problems to be solved by the invention]

However, it has not been recognized that the peripheral speed ratio must be controlled using the relationship between the peripheral speed ratio and the neutral point position of the upper and lower rolls in consideration of the stability of rolling in different speed rolling.

In the different speed rolling state, unlike the constant speed rolling, one neutral point position may jump to the inlet side even after passing the strip. At this time, if the other neutral point position is within the rolling contact arc, even if the advanced ratios of the upper and lower rolls are monitored, it is possible to determine only that both neutral points do not project to the exit side of the rolling contact arc. Misjudging that it is a special rolling. Therefore, there is a possibility that stable rolling cannot be performed only by monitoring the advanced rate. Further, the neutral point position constantly moves due to fluctuations in parameters such as front and rear tension and plate thickness. In addition, from the plate speed and the roll peripheral speed, it is only recognized that the neutral point position is not out of the limit.
It was necessary to put a constraint on the maximum torque. By measuring the tension in the front and rear, plate thickness, both work roll peripheral speeds, and calculating the neutral point position, the neutral point position is monitored, and even if the neutral point position moves during control during rolling, It was not known to monitor the neutral point position within limits by calculating the neutral point position.

An object of the present invention is to monitor the neutral point of the upper and lower work rolls by using the relationship between the rolling specifications and the neutral point position of the upper and lower rolls, and to perform a good control of the neutral point of the upper and lower work rolls, thereby controlling a stable rolling facility. To provide.

[Means for solving problems]

In order to achieve the above-mentioned object, in the present invention, a pair of work rolls, a pair of drive devices that drive each work roll at a predetermined peripheral speed ratio, and a speed control device that controls each of the drive devices to a set speed are provided. In the control method of the rolling equipment, the input side and the outgoing side plate thickness of the rolling equipment, the front and rear tensions and the work roll speeds are input signals, and the high speed side work rolls are produced by the different speed rolling model using the input signals. Calculate the neutral point position of the low speed side work roll, and monitor whether the calculated neutral point position is within the work roll contact angle region,
The neutral point position is controlled so that the neutral point position does not overflow the contact angle region.

Then, as the different speed rolling model, a model derived by the relationship between the plastic deformation of the rolled material and each roll speed of the rolling equipment is used, or, when each roll speed is a constant speed The relationship between the difference from the total rolling force and the amount of movement of each neutral point position of each roll from the time of constant velocity is used as a model.

Further, monitoring whether or not the neutral point position is within the work roll contact angle region, the neutral point position calculated by the model is calculated by the distance from the roll exit of the rolled material, and the neutral point distance is positive. The value is determined to be normal by the fact that it is shorter than the value and the roll contact length.

Further, controlling the neutral point position is to change the command of the speed control device in proportion to the change amount of the neutral point position, or corresponding to the change amount of the neutral point position. It is configured to change the command value of the front and rear tension of the rolling equipment, or to change the target value of the outlet plate thickness of the rolling equipment in accordance with the change amount of the neutral point position. Is.

[Action]

The relationship between the rolling specifications and the neutral point position of the upper and lower rolls is modeled, and the neutral point is controlled using the model.

More specifically, the input and output plate thicknesses of the rolling equipment, the front and rear tensions of the rolling equipment and the work roll speed are used as input signals, and the input signals are used to perform the high speed side work rolls and the low speed side by the different speed rolling model. Calculate the neutral position of the work roll,
It is to monitor whether the calculated neutral point position is within the work roll contact angle region, and to control the neutral point position so that the neutral point position does not extend beyond the contact region.

In other words, the rolling specification is used as an input signal, the neutral point position is calculated by the model in consideration of the front and rear tensions of the rolling equipment, and the neutral point is controlled so that the neutral point does not protrude from the contact area. is there. As a result, the neutral point of the upper and lower work rolls can be well controlled, and a stable method for controlling the rolling equipment is provided.

〔Example〕

Embodiments of the present invention will be described with reference to the drawings. First, the basic items will be explained.

FIG. 2 shows that, in a rolling schedule, the rolling load P is distributed at the peripheral speed in the rolling contact arc, that is, when the upper roll contact angle θ _L is between 0 (outlet) and the total contact angle θ _m (inlet). is a characteristic diagram showing how changes to the Te ratio G _V Niyotsu. The peripheral speed ratio G _V is represented by the ratio of the high-speed roll peripheral speed to the low-speed roll peripheral speed.

In FIG. 2, the curve of the peripheral speed ratio G _V = α ₀ = 1 shows the characteristic of constant speed rolling. In constant-velocity rolling, the upper and lower neutral point positions are symmetrical with respect to the material to be rolled, and therefore the contact angles of the upper and lower neutral points are equal when θ _L is used. The pressure distribution has a triangular shape with the maximum value at the position of the neutral point contact angle φ ₀ of constant velocity rolling or the like.

In FIG. 2, the curve of the peripheral speed ratio G _V = α ₁ > 1 shows the characteristic of different speed rolling. In different speed rolling, the high speed side neutral point moves to the rolling exit side and the low speed side neutral point moves to the rolling input side from the neutral point position during constant speed rolling. The low-speed side and high-speed side neutral point positions are represented by φ _L and φ _H , respectively. The movement amount at this time is
The angles from the neutral point contact angle φ ₀ at the time of constant speed rolling are used to represent the low-speed side and high-speed side neutral point movement amounts Δφ _L and Δφ _H. The pressure distribution has a trapezoidal shape.

In each region, the following distributed load equations for different speed rolling models can be derived from horizontal and vertical balance equations and yield condition equations. In this _{case, C A} C B C C _φ
H φ _L is an unknown number.

Furthermore, continuous conditions at neutral point position θ _L = φ _H in _{P A (φ H) = P} B (φ H) θ L = φ L in _{P B (φ L) = P} C (φ L), neutral Considering the relationship of volume velocity at the point position, the inlet condition and the outlet condition of the rolling region, the unknowns C _A , C _B , C _C neutral point positions φ _H , φ _L of the equations (1) to (3) are calculated from these. .

The neutral point position of the high-speed side and low-speed side work rolls can be calculated using the above model. Thereby, the neutral point position is monitored.

When both of the neutral point positions are within the range of the total contact angles of the work rolls on the corresponding sides, stable rolling can be performed. From this, when the neutral point position is being monitored, if any one of them deviates from the area of the corresponding total contact angle, the rolling specifications such as the peripheral speed ratio should be corrected so that stable rolling can be performed. It is conceivable to correct the neutral point position.

Since the correction amount of the rolling specification can be set by using the model described above, the neutral position is controlled by this.

An embodiment of the present invention will be described below with reference to FIG. First
The figure is a flowchart for explaining the method of calculating the neutral point position. FIG. 1 shows unknowns φ _L , φ _H , C _A , and C of equations (1) to (3).
_{B 1} and C _C are calculated using the input side and output side conditions and the continuous condition. Input is input side, output side plate thickness H, h, tension t _b ,
t _f , friction coefficient, base material thickness, plate speed, peripheral speed ratio G _V , roll radii _RL , _RH , and the like.

The relationship between the flat roll radii R ′ _L , R ′ _H and the rolling force P is
Substituting the obtained rolling force into the Hitkotoku formula, R _L ′, R
_H'is obtained, compared with the previous _RL 'and _RH ', and a convergence calculation is performed. (If the initial value of _RL 'and _RH ' is set to the convergence value at the previous calculation, the convergence is calculated. It takes less time to calculate).

When converged, it means that the obtained neutral points φ _L and φ _H satisfy the rolling conditions. If the limiting conditions are not met on the way, the required neutral points φ _L and φ _H
Means that the rolling conditions are not satisfied.

Other methods for detecting both neutral point positions are described above.
Possible methods include analytically solving equations (1) to (3) and deriving an approximate equation. For example, when the rolling specifications are constant,
When the peripheral speed ratio G _V is changed, the neutral point movement amount can be approximated as follows.

The relationship between the peripheral speed ratio G _V and the neutral point movement amounts Δφ _L , Δφ _H is
Consider expressing it as a function of G _V. By the function approximation, for example, the following equation can be expressed.

Δφ _L = b ₀ G _V ⁿ + b ₁ G _V ^n-1 +… + b _i G _V ⁿⁱ +… + b _n ……… (4) Δφ _H = c ₀ G _V ⁿ + c ₁ G _V ^n-1 + … + C _i G _V ^n-1 +… + c _n (5) b _i = fφ _L (H, h, t _f , t _b , μ _L , μ _H …) (6) c _i = fφ _H (H, h, t _f , t _b , μ _L , μ _H ...) (7) n: order of approximation i: integer 0 to n b _i , c _i : rolling schedule, plate thickness, tension, friction coefficient, etc. It is a constant because the rolling schedule is given by the function of, and becomes the coefficient of the term of G _{V in} the equations (4) and (5).

H: thickness at entrance side h: exit side thickness t _f: exit-side unit tension t _b: inlet side unit Tension mu _L: low-speed side roll of friction coefficient mu _H: high speed side roll coefficient of friction (4) to (7) G _It is used as a model formula for _V movement.

The equations (6) and (7) are obtained by solving the above equations (1) to (3) according to the conditions, and the solution is subjected to regression analysis with G _V , and its coefficients b _i and c _i are H, It is an equation created by re-regressing with parameters such as h, t _f , and t _b , and its functional form can be expressed as follows.

b _i = α ₀ + α ₁ ^* H + α ₂ ^* h + α ₃ ^* t _f + α ₄ ^* t _b + α ₅ ^* μL + α ₆ ^* μH ………
_{(6 ') c 1 = β} 0 + β 1 * H + β 2 * h + β 3 * t f + β 4 * t b + β 5 * μL + β 6 * μH .........
(7 ′) Next, at a certain peripheral speed ratio G _V , the vertical neutral point position φ _L ,
It is necessary to check if φ _H is within the rolling contact arc.

These can be expressed as follows using the neutral point movement amounts Δφ _L and Δφ _H.

_{θ m -φ 0> Δφ L>} 0 ......... (8) φ 0> Δφ H> 0 ......... (9) (8) (9) formula used in a checking of the rollable conditions during _{G V} fixed.

An application example of the present invention is shown in FIG.

The calculator 24 calculates two neutral point positions from the measured values of the plate thickness and tension on the inlet side and the outlet side and the peripheral speed ratio. Ie
(1) to (3) the unknowns _{C A C B C C φ L} φ H of Formula measured by means of a continuous conditions at neutral point.

If the two neutral point positions deviate from the conditions for stable rolling (conditions of formulas (8) and (9)), the determination unit 25 issues an instruction to correct the peripheral speed ratio. The peripheral speed ratio corrected by the setter 21 is input to the calculator 24, and the two neutral point positions are calculated again.

If the two neutral point positions satisfy the conditions for stable rolling, the two neutral point positions are set to the roll peripheral speed setters 15 and 1.
Enter in 6.

The roll peripheral speed setters 15 and 16 convert the two neutral point positions into respective roll peripheral speeds according to the command value of the outlet plate speed.

In the embodiment shown in FIG. 3, the respective values are obtained as follows, but it goes without saying that other methods can be used.

The plate thickness of the load meter 6 attached to the backing roll 3 and the roll gear up detector 7 attached to the backing roll 4 are
The rolling load P and the roll gear S are respectively detected. The calculator 20 calculates the outgoing side plate thickness h of the material 5 to be rolled from these inputs using the well-known Hook's law. Ie K: Mill Rigidity Coefficient The entrance side plate thickness is a value obtained by delaying the exit side plate thickness of the rolling device at the preceding stage by the time period during which the material 5 to be rolled is moved.

The tension is detected by a tensiometer 8 provided on the entrance side of the material 5 to be rolled. The tension control device 9 converts the tension into the plate speed.

The roll peripheral speeds are set in the roll speed control devices 13 and 14 output from the roll peripheral speed setters 15 and 16 based on the roll peripheral speeds from the low speed side and high speed side neutral points and the exit side plate speed.

It should be noted that as a method for the computing unit 24 to calculate the two neutral point positions from the measured values of the plate thicknesses on the inlet and outlet sides, the tension, and the circumferential speed ratio, the equations (4) and (5) can be used. . At this time, the determination unit 25 uses equations (8) and (9). The deviation can be stably corrected by controlling the peripheral speed ratio during different speed rolling with a constant peripheral speed ratio.

〔The invention's effect〕

ADVANTAGE OF THE INVENTION According to this invention, the neutral point position of an up-and-down work roll can be monitored, a neutral point can be controlled well, and the control method of the rolling installation with stability can be provided.

Further, it becomes possible to control the rolling in a stable rolling state by making the rolling in a different speed state uniform due to the difference in roll diameter and the like.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a method for calculating the neutral point position, FIG. 2 is a characteristic diagram showing a relationship between a contact angle and a distributed load, and FIG. 3 is a control method for a different speed rolling mill according to the present invention. It is a figure which shows the application example of. 1 ... upper work roll, 2 ... lower work roll, 3, 4 ...
Backing roll, 5 ... Rolled material, 6 ... Load cell, 7 ... Roll gear gap detection device, 8 ... Tensile meter, 9 ... Tension control device, 13, 14 ... Speed control device, 24 ... Rolling specification An arithmetic unit for calculating the positions of both neutral points from 25, ... A determination unit for determining whether the positions of both neutral points satisfy the conditions, 15, 16
...... Roll peripheral speed setting device, 21 ...... Roll speed ratio setting device.

Claims (7)

[Claims] 1. A method of controlling rolling equipment comprising a pair of work rolls, a pair of drive devices for driving the work rolls at a predetermined peripheral speed ratio, and a speed control device for controlling the drive devices to respective set speeds. In, the input and output plate thicknesses of the rolling equipment, the front and rear tensions and the work roll speeds are used as input signals, and the input signals are used to neutralize the high speed work rolls and the low speed work rolls by the different speed rolling model. The point position is calculated, whether the calculated neutral point position is within the work roll contact angle region is monitored, and the neutral point position is controlled so that the neutral point position does not extend beyond the contact angle region. A method for controlling rolling equipment, comprising: 2. The rolling mill control method according to claim 1, wherein the different speed rolling model is a model derived from the relationship between the plastic deformation of the rolled material and each roll speed of the rolling mill. A method for controlling rolling equipment, which is characterized by being used. 3. The method for controlling rolling equipment according to claim 1, wherein, as the different speed rolling model, a difference between a total rolling force when each roll speed is constant and each roll A method for controlling rolling equipment, characterized in that the relationship between the amount of movement of each neutral point position from the time of constant velocity is used as a model. 4. The rolling mill control method according to claim 1, wherein the monitoring of whether or not the neutral point position is within a work roll contact angle region is performed by the neutral point calculated by the model. A method for controlling rolling equipment, characterized in that a position is calculated from a distance from a roll outlet of a rolled material, and normal is determined when the neutral point distance is shorter than a positive value and a roll contact length. 5. The method for controlling rolling equipment according to claim 1, wherein controlling the neutral point position changes the command of the speed control device in proportion to the change amount of the neutral point position. A method for controlling rolling equipment, comprising: 6. The rolling mill control method according to claim 1, wherein controlling the neutral point position corresponds to a change in the forward and backward tension of the rolling facility corresponding to a change amount of the neutral point position. A method for controlling rolling equipment, characterized by changing a command value. 7. The method for controlling rolling equipment according to claim 1, wherein controlling the neutral point position corresponds to a change of the neutral point position in relation to the exit side plate thickness of the rolling equipment. A method for controlling rolling equipment, characterized by changing a target value.