JPH03248707A - Controller for web widening mill - Google Patents

Abstract

PURPOSE:To prevent the meandering of rolled stock and crack of web and to smoothly perform web widening rolling by correcting the set value of roll speed and set value of rolling down based on the difference of rolling torque of the right and left rolls of a web widening mill in a direction in which that difference is decreased. CONSTITUTION:Means 19, 20 for detecting rolling torque with which the rolling torque of each of the right and left rolling rolls 1, 2, 3, of 4 of web widening rolling mill is detected, means 21 for calculating rolling torque difference with which the rolling torque difference of the right and left rolling rolls 1, 2, 3, 4 is calculated, speed compensating means 22 with which the set value of speed is corrected in a direction that the speed of rolling roll on a larger side of rolling torque is decreased according to the calculated rolling torque difference and rolling-down compensating means 24 with which the correction value of rolling down that the max. value is limited corresponding to rolling torque difference is determined and which the set value of rolling- down is corrected in a direction that the rolling reduction on the larger side of rolling torque is deceased according to this correction value of rolling reduction are provided. In this way, the meandering of rolled stock and crack of web are prevented and smooth web widening rolling is made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a section steel rolling facility, and particularly to a control device for a web widening mill.

(Prior Art) In this type of web widening rolling mill, as shown in FIG. 2(a) is a front view of the rolling section, and FIG. 2(b) is a plan view thereof, the upper right roll 1 is , a lower right roll 2, an upper left roll 3, and a lower left roll 4 are arranged symmetrically to each other.

The rolled material 5 rolled by these rolls forms an H-beam with webs 6 and flanges 7. In this case, the upper right roll 1 and the upper left roll 3 are arranged so that their respective rotation axes form a "V" shape with respect to each other, and the lower right roll 2 and the lower left roll 4 are arranged in the same manner. And the gap between the upper right roll 1 and the lower right roll 2,
The gap between the upper left roll 3 and the lower left roll 4 is set by the right rolling device 8 and the left rolling device 9 so that the web thickness on the exit side of this web widening rolling mill is set to a desired value. The width is expanded by the amount that is thinned by the roll.

FIG. 2 is a block diagram showing the configuration of a control device for a web widening rolling mill. In the figure, a speed control device 11 controls a right roll drive motor 10 that drives an upper right roll 1 and a lower right roll 2, and a speed control device 13 controls a left roll drive motor 12 that drives an upper left roll 3 and a lower left roll 4. It is meant to be controlled. On the other hand, the rolling speed setting device 14
The rolling speed setting value is converted by the roll diameter compensation circuit 15 into the rotation speed of the left roll, and by the roll diameter compensation circuit 17 into the rotation speed of the right roll. Further, with these rotation speeds as preset values, the left roll rotation speed setting circuit 16 gives the left roll rotation speed setting value to the speed control device 13, and the right roll rotation speed setting circuit 18 gives the right roll rotation speed setting value to the speed control device 11. give to

Thereby, the material to be rolled 5 is widened at the speed set by the rolling speed setting device 14.

(Problem to be solved by the invention) In the conventional web widening rolling mill control device described above, the roll diameters are set in the roll diameter compensation circuits 15 and 17, or the set values and the actual values are different. In addition, the diameters of the left and right rolls may differ from each other. For this reason, a difference occurs between the peripheral speeds of the left and right rolls, and the load on the electric motor that drives the rolls also becomes unbalanced. in this way,
When the loads on the left and right motors become unbalanced, the rolled material bends toward the side where the circumferential speed of the roll is slow on the exit side of the rolling mill, causing a phenomenon called meandering. If the degree of meandering becomes large, abnormal situations such as getting caught in the side guide on the entry side of the finishing rolling mill or being unable to bite into the entry side of the finishing rolling mill will occur, which will seriously impede operations. There was a problem.

In addition, the amount of reduction of the right reduction device 8 and the left reduction device 9 is set by a roll reduction setting device (not shown), or depending on the degree of setting error, cracks may occur at the joint between the web 6 and the flange 7. There were also problems.

This invention was made to solve the above-mentioned problems, and can prevent meandering of the rolled material and cracking of the web caused by errors in setting the diameters of the left and right rolls and errors in setting the rolling reduction amount, thereby ensuring smooth rolling. An object of the present invention is to obtain a control device for a web widening rolling mill that enables web widening rolling.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a web widening mill for widening a web of a shaped steel using four rolling rolls arranged symmetrically in the upper and lower and left and right directions when viewed from the rolling direction. A rolling torque detection means for detecting the rolling torque of each of the right rolling rolls, a rolling torque difference calculating means for calculating the rolling torque difference between the left and right rolling rolls, and a side with a larger rolling torque according to the calculated rolling torque difference. A speed compensating means corrects the speed set value in a direction in which the rolling roll speed decreases, and a rolling amount correction value whose maximum value is limited corresponding to the rolling torque difference is determined, and the rolling torque is adjusted according to this rolling amount correction value. It is provided with a reduction compensating means for correcting the reduction setting value in a direction in which the amount of reduction on the larger side decreases.

(Function) In this invention, the rolling torque difference between the left and right rolling rolls is determined, and the rolling roll speed setting value is corrected so that this rolling torque difference is reduced. Meandering of the rolled material is prevented, and since the roll reduction amount is corrected so as to reduce the rolling torque difference, cracking of the web due to an error in setting the reduction amount can be prevented.

(Embodiment) FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. In the figure, the same elements as in FIG. 4 are given the same reference numerals and their explanations will be omitted. Here, the right roll rolling torque detection circuit 19 detects the right roll rolling torque based on the current 11 and the rotation speed N1 of the right roll drive motor 10, and also detects the right roll rolling torque based on the current I2 and the rotation speed N2 of the left roll drive motor 12. The left roll rolling torque detection circuit 20 detects the right roll rolling torque. Further, the detected right roll rolling torque is calculated by a subtracter 2 as a rolling torque difference calculation means.
As the subtracted input of 1, the left roll rolling torque is subtracted by subtractor 2.
] are respectively added as subtraction inputs, and this subtractor 21
The difference in rolling torque between the left and right sides is calculated by . Then, this rolling torque difference is taken into the circumferential speed compensator 22,
Here, a circumferential speed compensation value that compensates for the rolling torque difference is converted into a rotational speed and output. This peripheral speed compensation rotation speed is added to the output of the roll diameter compensation circuit 15 by an adder 23 and is applied to the left roll rotation speed setting circuit 16. On the other hand, the rolling torque difference calculated by the subtractor 21 is applied to the rolling reduction compensator 24. This reduction compensation device 24 includes a function generator 24A that responds to a positive rolling torque difference and outputs a reduction correction value according to the magnitude when the difference exceeds a certain value, limiting the maximum value thereof, and The function generator 24B responds to the torque difference and outputs a reduction correction value according to the magnitude when the torque difference exceeds a certain value, limiting the maximum value thereof. Further, the output of the function generator 24A is added to the right roll reduction preset value by the adder 25 and applied to the right roll reduction setting device 27, and the output of the function generator 24B is added to the right roll reduction preset value by the adder 25.
6, it is added to the left roll reduction preset value and applied to the left roll reduction setting device 28.

The operation of this embodiment configured as described above will be explained below.

First, the right roll rolling torque detection circuit 19 calculates the rolling torque of the right roll based on the current I and rotation speed N1 of the right roll drive motor 10, that is, the portion obtained by removing acceleration/deceleration torque from the torque generated by the motor, using the following formula. do.

T -K Φ I-CD2・dN/dt...(1
) R1111 or TR1' right roll rolling torque (kgφm) K1φ1:
Constant (kg-m/A) I1: Right roll drive motor current (A) CD2: Total flywheel effect of right roll (kg-m/A): Right roll motor rotation speed (rpm).

Next, the left roll rolling torque detection circuit 20 calculates the rolling torque of the left roll according to the following formula based on the electric current of the left roll drive motor 12 and the rotation speed N2.

TR2=2Φ212-CD -dN2/dt...(
2) However, "R2' has 2Φ2: I2°CD2: N2:.

Left roll rolling torque (kg-m) Constant (kg-m/A) Left roll drive motor current (A) Total flywheel effect of left roll (kg-rf) Left roll motor rotation speed (rpm) Obtained in this way The right roll rolling torque T and the left roll rolling torque "R2" are added by 1 to a subtracter 21, and the rolling torque difference TR1"R2 is calculated here.

Additionally, this rolling torque difference TR□-TR□ is added to the circumferential speed compensator 22, where by multiplying by an appropriate gain K, the circumferential speed compensation value that compensates for the rolling torque difference is converted into the rotation speed. Output. This peripheral speed compensation value is added to the output of the roll diameter compensation circuit 15 by an adder 23 and is applied to the left roll rotation speed setting circuit 16.

If the left roll rolling torque "R2" increases more than the right roll rolling torque TR1, negative compensation is made to the left roll rotation speed setting circuit 16, thereby automatically changing the left roll rotation speed. As a result, the rolling torques on the left and right sides become balanced. That is, the circumferential speeds of the rolls are made equal, and the material speeds on the left and right sides are also made equal, making it possible to prevent meandering of the rolled material.

On the other hand, if the right roll rolling torque TR1 is larger than the left roll rolling torque TR2, the function generator 24A forming the roll compensation device 24 outputs a roll correction value, which is added to the right roll preset value. Therefore, the set value of the roll reduction of the right roll reduction setter 27 increases and the reduction amount is reduced, thereby reducing the rolling torque of the right roll and preventing excessive reduction blades from working. In this case, the function generator 24A has a dead band that generates an output only when the difference between the rolling torque of the right roll and the rolling torque of the left roll exceeds a certain value, and an upper limit that prevents the compensation output from exceeding a certain value. It has the characteristic of having a limit.

On the contrary, when the left roll rolling torque R2 is larger than the right roll rolling torque R1, the function generator 24B that constitutes the roll compensation device 24 outputs a roll correction value, and the left roll preset value is changed to the left roll rolling torque. will be added.

Therefore, the roll reduction set value of the left roll roll reduction setter 28 becomes large and the roll reduction amount is decreased, and an excessive reduction blade is prevented from acting on the left roll. Note that this function generator 24
Roller B also has a dead band that produces an output only when the rolling torque difference exceeds a certain value, and an upper limit that prevents the output from producing a compensation output that exceeds a certain value.

In the above example, the speed of the rolling roll on the side where the rolling torque is larger is reduced to equalize the material speed on the left and right sides, but although this is not necessarily practical, instead of this, the rolling roll speed on the side where the rolling torque is smaller is reduced. Similar results can be obtained by increasing the speed.

In addition, in the above example, the reduction set value on the side where the rolling torque is larger is increased to prevent web cracking, or alternatively, the same effect can be obtained by decreasing the reduction setting value on the side where the rolling torque is smaller. can get.

Furthermore, in the above embodiments, the web width of H-beam steel was explained, but the present invention is not limited to this.
Needless to say, the present invention can also be applied to web widening of other section steels consisting of webs and flanges.

〔Effect of the invention〕

As is clear from the above explanation, according to the second invention, based on the rolling torque difference between the left and right rolls, the roll speed setting value is corrected in a direction that reduces the difference, thereby preventing meandering of the rolled material. In addition, based on the rolling torque difference between the left and right rolls, the rolling reduction set value is corrected in the direction that reduces the difference, which makes it possible to prevent web cracking. Smooth web widening rolling becomes possible.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.
FIGS. 2(a) and 2(b) are a front view and a plan view of the main parts to which the present invention is applied, and FIG. 3 is a block diagram showing the configuration of a control device for a conventional web widening mill. 1... Upper right roll, 2... Lower right roll, 3... Upper left roll, 4... Lower left roll, 9... Right lowering device,
1o...Right roll drive motor, 11.13...Speed control device, 12...Left roll drive motor, 14...Rolling speed setting device, 15...Roll diameter compensation circuit, 16...
Left roll rotation speed setting circuit 17...Roll diameter compensation circuit,
18... Right roll rotation speed setting circuit, 19... Right roll rolling torque detection circuit, 20... Left roll rolling torque detection circuit, 21... Subtractor, 22... Peripheral speed compensator, 23 .25.28... Adder, 24... Roll reduction compensator, 27... Right roll reduction setting device, 28... Left roll reduction setting device.

Claims (1)

[Claims] Rolling torque detects the rolling torque of each of the left and right rolling rolls in a web widening mill that widens the web of a section steel using four rolling rolls arranged symmetrically in the upper and lower and left and right directions when viewed from the rolling direction. a detection means, a rolling torque difference calculating means for calculating a rolling torque difference between the left and right rolling rolls, and a speed setting value in a direction in which the speed of the rolling roll on the side with a larger rolling torque decreases according to the calculated rolling torque difference. A speed compensation means to be corrected and a reduction amount correction value whose maximum value is limited in accordance with the rolling torque difference are determined, and the reduction setting value is set in a direction in which the reduction amount on the side where the rolling torque is larger is decreased according to the reduction amount correction value. 1. A control device for a web widening rolling mill, comprising a rolling reduction compensating means for correcting.