KR101239187B1 - Method and apparatus for controlling elongation in two-stand skin pass mill - Google Patents

Abstract

The present invention relates to a steel sheet elongation control device and a control method of a two-stand rolling mill, and more particularly, by using the rolling reduction ratio to individually apply the speed compensation value of the master speed value after the first and second rolling to secure the target elongation. It is related with the steel plate elongation control apparatus and control method of a 2-stand tempered rolling mill. The steel sheet elongation control device of the two-stand rolling mill according to the present invention receives the master speed value MS0, feeds back the side tension value T2 measured in the steel sheet which has passed through the entrance bridle roll, and then returns the target lateral tension value ( A side tension control unit 121 for controlling a roll speed of the shear rolling mill to follow T2 _ref ); An intermediate that receives the master speed value MS1 and controls the roll speed of the post rolling mill to follow the target intermediate tension value T3 _ref by feeding back the intermediate tension value T3 measured in the steel sheet passing through the shear rolling mill. Tension control unit 131; The speed of the exiting bridal roll is controlled to follow the target exiting tension value T42 _ref by feeding back the exiting tension value T4 measured in the steel sheet passing through the rear end rolling mill by receiving a master speed value MS2. Characterized in that it comprises a departure tension control unit 141.

Description

2 METHOD AND APPARATUS FOR CONTROLLING ELONGATION IN TWO-STAND SKIN PASS MILL}

The present invention relates to a steel sheet elongation control device and a control method of a two-stand rolling mill, and more particularly, by using the rolling reduction ratio to individually apply the speed compensation value of the master speed value after the first and second rolling to secure the target elongation. It is related with the steel plate elongation control apparatus and control method of a 2-stand tempered rolling mill.

Continuous Annealing Line (CAL) promotes grain growth by heating the steel sheet above the recrystallization temperature, thereby eliminating the brittleness of the steel sheet formed during cold rolling and providing workability. The stripped steel strip may cause warpage of the plate over time when the free movement of the internal employment atoms (C, N) becomes active and the product is produced as it is, and the drawing may occur unevenly during processing. .

Therefore, the target elongation and elongation control of the temper mill located at the exit side of the furnace means that dislocations are forcibly formed inside the plate to suppress the free movement of the employment atoms C and N, thereby preventing warpage of the plate. ) And to improve workability.

Conventional temper rolling mill is composed of one rolling mill, but as products with higher tensile strength are gradually developed, there is a problem that the target elongation cannot be secured with one rolling mill. The rolling mill is continuously installed and rolled into a two-stand rolling mill. Doing

In general, the method of controlling steel sheet elongation of a two-stand rolling mill should have information on elongation prediction according to the exact load of each mill. However, it is very difficult to accurately estimate the load of each rolling mill according to the steel grade, size, and roll diameter change. Especially, setting the appropriate load in succession of two rolling mills is work hardening in the second rolling mill after the rolling of the first rolling mill. This is even more difficult because the characteristics must be taken into account.

As a method of controlling the steel sheet elongation of the two-stand rolling mill, a method of compensating the master speed after the first and second rolling with one design elongation and applying a separate variable of load and tension have been proposed. Because of this, it is difficult to use easily in the actual process.

An object of the present invention is to ensure the target elongation of the steel sheet by performing the compensation of the master speed value after the primary and secondary rolling, respectively, by using the reduction ratio of the front and rear rolling mills while fixing the reduction force. It is to provide a steel sheet elongation control device and a control method of a two-stand rolling mill.

In the steel sheet elongation control device of the two-stand rolling mill according to the present invention, the entrance bridle roll, the shear rolling mill, the rear end rolling mill and the exit bridal roll are connected in sequence, and the entrance bridle roll is driven at a master speed value MS0. A steel sheet elongation control device of a stand rolling mill, which receives a master speed value (MS0), feeds back the measured side tension value (T2) measured on the steel sheet passing through the side bridle roll, and follows the target side tension value (T2 _ref ). A side tension control unit 121 for controlling a roll speed of the shear rolling machine; The master speed value MS1 calculated by the following equation (1) is input, and the intermediate tension value T3 measured in the steel sheet passing through the shear rolling mill is fed back to follow the target intermediate tension value T3 _ref . Medium tension control unit 131 for controlling the roll speed of the after mill

MS1 = MS0 · [1+ K / (K + 1)] · εt equation (1)

(Where K is P1 / P2, P1 is the shear reduction force value of the shear mill, P2 is the trailing force force value of the trailing mill, and εt is the design elongation of the steel sheet); The master speed value MS2 calculated by the following equation (2) is input, and the feed back tension value T4 measured in the steel sheet passing through the post rolling mill is fed back to follow the target outgoing tension value T42 _ref . Exit tension control unit 141 for controlling the speed of the exit bridal roll

MS2 = MS1 [1 + 1 / (K + 1)] εt equation (2);

It characterized in that it comprises a, the shear reduction force value (P1) is preferably set to the maximum reduction force value of the shear rolling mill.

The entry tension control unit 121 may include a entry tension control device 122 that calculates a difference value between the entry tension value T2 and a target entry tension value T2 _ref ; A second speed control device (123) for calculating a compensation master speed value (MS0 ') of the master speed value (MS0) corresponding to the difference value as a backup roll drive motor speed of the shear rolling mill; And a second current control device 124 that calculates a drive current value of the backup roll drive motor corresponding to the backup roll drive motor speed.

The intermediate tension control unit 131 may include an intermediate tension control device 132 that calculates a difference value between the intermediate tension value T3 and a target intermediate tension value T3 _ref ; A third speed control device (133) for calculating a compensation master speed value (MS1 ') of the master speed value (MS1) corresponding to the difference value as a backup roll driving motor speed of the rear end rolling mill; And a third current control device 134 for calculating a drive current value of the backup roll drive motor corresponding to the backup roll drive motor speed.

The tensioning tension control unit 141 may include: a tensioning tension control device 142 that calculates a difference value between the measurement tension value T4 and a target measurement tension value T4 _ref ; A fourth speed control device (143) for calculating a compensation master speed value (MS2 ') of the master speed value (MS2) corresponding to the difference value as a drive motor speed of the exit bridal roll; And a fourth current control device 144 that calculates a driving current value of the exiting bridal roll driving motor corresponding to the driving motor speed of the exiting bridal roll.

The steel sheet elongation control method of the two stand rolling mill which concerns on this invention is a steel plate elongation control method of the two stand rolling mill in which the entrance bridle roll, the shear rolling mill, the rear end rolling mill, and the exit bridal roll are connected in order, (a) the said entrance bridle roll Driving to the master speed value MS0; (b) driving the roll of the shear rolling mill by feeding back the input tension value T2 measured in the steel sheet passing through the entrance bridle roll to compensate the master speed value MS0; (c) feeding back the intermediate tension value T3 measured in the steel sheet passing through the shear rolling mill, and compensating the master speed value MS1 calculated by Equation (1) to drive the roll of the post rolling mill;

MS1 = MS0 · [1+ K / (K + 1)] · εt equation (1)

(Where K is P1 / P2, P1 is the shear reduction force value of the shear mill, P2 is the trailing force force value of the trailing mill, and εt is the design elongation of the steel sheet); And (d) driving the exit bridal roll by feeding back the exit tension value T4 measured in the steel sheet passing through the rear end rolling mill to compensate for the master speed value MS2 calculated by Equation (2) below.

MS2 = MS1 · [1 + 1 / (K + 1)] · εt equation (2)

It characterized in that it comprises a, the shear reduction force value (P1) is preferably set to the maximum reduction force value of the shear rolling mill.

The steel sheet elongation control device and control method of the two-stand rolling mill according to the present invention has the following effects.

(1) Compensation values of master speed values after primary and secondary rolling are easily calculated using only the rolling reduction ratios of the front and rear rolling mills, providing a working environment in which drivers of the two stand rolling mills can easily obtain the target elongation. .

(2) Fix the rolling force of the front and rear end rolling mill, but set the rolling down force of the front end rolling mill to the maximum rolling force, and fix the rear end rolling force to the steel type, reducing the number of control variables to be considered for simple and accurate feedback. Provided is a steel sheet elongation control device and control method for a two-stand rolling mill.

(3) The steel sheet applies the characteristic that the yield strength increases after the primary deformation, and sets the reduction force of the shear rolling mill to the maximum reduction force, thereby obtaining the maximum stretching effect.

1 illustrates elongation control logic of a steel sheet elongation control apparatus of a two-stand rolling mill according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. 1 illustrates elongation control logic of a steel sheet elongation control apparatus of a two-stand rolling mill according to an embodiment of the present invention.

The two-stand rolling mill according to the present invention has a configuration in which the entry bridle roll 110, the shear rolling mill 120, the rear end rolling mill 130 and the exit bridal roll 140 are continuously connected. The two-stand rolling mill prevents plate breakage between the entry bridle roll 110 and the shear rolling mill 120 and between the post rolling mill 130 and the exit bridal roll 140, as shown in FIG. 1 to achieve smooth rolling. The same tension constant control system is constructed, and a constant rolling force is set between the front end mills 120 and the rear end mill 130.

The shear rolling mill 120 applies the reduction force corresponding to the shear reduction force value P1 to the steel sheet 1 by the shear reduction force control unit 127, and the trailing mill 130 is rearwarded by the trailing reduction force control unit 137. The reduction force corresponding to the reduction force value P2 is applied to the steel sheet 1.

Here, the shear reduction force value P1 and the trailing force reduction force value P2 are fixed to values set according to the corresponding steel grades. Particularly, after the first deformation of the steel sheet, the yield strength is increased, and the shear rolling force value P1 is set to the shear rolling mill 120 so that the stretching effect of the shear rolling mill 120 on the steel sheet is greater than that of the rear rolling mill 130. It is preferable to set the maximum reduction force value of) and change and fix the rear reduction force value P2 in accordance with the steel grade.

The steel sheet 1 passing through the entrance bridle roll 110, the shear rolling mill 120, the rear end rolling mill 130, and the exit bridal roll 140 has an entrance tension measuring unit 151, an intermediate tension measuring unit 152, and an exit side. In the tension measuring unit 153, the entry tension value T2, the intermediate tension value T3, and the exit tension value T4 are respectively measured.

When the master speed value MS0 is input, the first speed control device 113 calculates the master speed value MS0 as the speed of the roll drive motor 115 of the entrance bridal roll 110, and the first current control device. 114 calculates this as a drive current value of the roll drive motor 115 to control the roll drive motor 115 speed.

The feedback tension value T2, the intermediate tension value T3, and the exit tension value T4 are feedback controlled by the entrance tension controller 121, the intermediate tension controller 131, and the exit tension controller 141, respectively. The input tension value T2, the intermediate tension value T3, and the exit tension value T4 follow the target entrance tension value T2 _ref , the target intermediate tension value T3 _ref , and the target exit tension value T4 _ref . Control is made,

The entry tension control unit 121 includes an entry tension control device 122, a second speed control device 123, and a second current control device 124. The intermediate tension controller 131 includes an intermediate tension controller 132, a third speed controller 133, and a third current controller 134. The exit tension controller 141 includes a exit tension controller 142, a fourth speed controller 143, and a fourth current controller 144.

The entry tension control device 122 calculates a difference value from the target entry tension value T2 _ref by feeding back the entry tension value T2 measured by the entry tension measuring instrument 151. Thereafter, the compensation master speed value MS0 ', which is the compensation value of the master speed value MS0, corresponding to the difference value calculated by the entry tension control device 122, is calculated, and the second speed control device 123 The speed of the backup roll drive motor 125 of the shear rolling mill 120 is calculated based on the compensation master speed value MS0 '. The second current control device 124 controls the speed of the backup roll drive motor 125 of the shear rolling mill 120 by calculating a drive current value of the backup roll drive motor 125 corresponding to the speed of the backup roll drive motor 125. do. Through the tension feedback compensation, the backup roll driving motor 125 of the shear rolling mill 120 is controlled such that the entry tension value T2 follows the target entry tension value T2 _ref .

The back-up roll drive motor 135 of the rear end mill 130 is also subjected to tension feedback control in a similar manner to the back-up roll drive motor 125 of the front end mill 120, but compensated by the output value of the intermediate tension controller 132. The new master speed value MS1 in which the elongation obtained by the shearing mill 120 is taken into account, rather than the master speed value MS0, is used. That is, the first master speed value compensator 161 multiplies the master speed value MS0 by "[1+ K / (K + 1)]. Εt" to output the master speed value MS1, which will be described later. Do it.

The intermediate tension control device 132 feeds back the intermediate tension value T3 measured by the intermediate tension measuring unit 152 to calculate a difference value from the target intermediate tension value T3 _ref . Thereafter, the compensation master speed value MS1 ', which is the compensation value of the master speed value MS1, corresponding to the difference value calculated by the intermediate tension control device 132, is calculated, and the third speed control device 133 Based on the compensation master speed value MS1 ′, the speed of the backup roll driving motor 135 of the rear mill 130 is calculated. The third current control device 134 calculates a drive current value of the backup roll drive motor 135 corresponding to the speed of the backup roll drive motor 135 to control the speed of the backup roll drive motor 135 of the after-roller 130. do. Through the tension feedback compensation, the backup roll drive motor 135 of the rear end mill 130 is controlled such that the intermediate tension value T3 follows the target intermediate tension value T3 _ref .

The roll drive motor 145 of the outboard bridal roll 140 is also subjected to tension feedback control in a similar manner to the backup roll drive motor 135 of the rear mill 130, but compensated by the output value of the outgoing tension controller 142. The new master speed value MS2 in consideration of the elongation obtained by the post rolling mill 130 is used, rather than the master speed value MS0 or MS1. That is, the second master speed value compensator 162 outputs the master speed value MS2 by multiplying the master speed value MS1 by "[1 + 1 / (K + 1)]. Εt", which will be described later. Do it.

The lateral tension control device 142 feeds back the lateral tension value T4 measured by the lateral tension measuring instrument 153 to calculate a difference value from the target lateral tension value T4 _ref . Thereafter, the compensation master speed value MS2 ', which is the compensation value of the master speed value MS2, corresponding to the difference value calculated in the landing tension control device 142, is calculated, and the fourth speed control device 143 The speed of the roll driving motor 145 of the exit bridal roll 140 is calculated based on the compensation master speed value MS2 '. The fourth current control device 144 controls the roll drive motor 145 speed of the exit bridal roll 140 by calculating a drive current value of the roll drive motor 145 corresponding to the roll drive motor 145 speed. . Through the tension feedback compensation, the roll driving motor 145 of the exit bridal roll 140 is controlled such that the exit tension value T4 follows the target exit tension value T4 _ref .

Hereinafter, a process of deriving the master speed value MS1 and the master speed value MS2 from the master speed value MS0 will be described.

In the two-stand rolling mill, the design elongation εt is set for each steel sheet, the entrance velocity V ₀ is measured by the entrance pulse generator 116 of the entrance bridle roll 110, and the exit pulse of the exit bridal roll 140 is measured. In the generator 146, the exit speed V ₂ is measured, and the intermediate speed V ₁ is not measured.

In the following induction equations, the elongation ε1 of the steel sheet 1 passed through the shear rolling mill 120 and the post rolling mill (P) by using the design elongation εt, the shear reduction force value P1 and the trailing reduction force value P2. The elongation ε2 of the steel sheet 1 passing through 130 can be obtained.

ε1 = (V ₁ -V ₀ ) / V ₀

ε2 = (V ₂ -V ₁ ) / V ₁

εt = (V ₂ -V ₀ ) / V ₀ ≒ ε1 + ε2

Abkhabi K,

Since K = ε1 / ε2 = P1 / P2,

εt = ε1 + ε2 = ε1 + ε1 / K = ε1 · [1 + (1 / K)]

Ε ε1 = [K / (K + 1)]

ε2 = [1 / (K + 1)]

Therefore, the master speed value MS1 of the steel sheet 1 passing through the front end stand 120 may be calculated as follows.

ε1 = (MS1-MS0) / MS0

MS1 = MS0 [1+ K / (K + 1)]

ε2 = (MS2-MS1) / MS1

MS2 = MS1 · [1 + 1 / (K + 1)] · εt

.

Therefore, the object to be compensated using the fed back tension value becomes the master speed value MS0 in the shearing mill 120, and becomes the master speed value MS1 in the rear mill 130, and the exit bridal roll 140. ) Is the master speed value MS2.

Preferred embodiments of the invention described above have been disclosed for purposes of illustration. Therefore, those skilled in the art having ordinary knowledge of the present invention will be capable of various modifications, changes, and additions within the spirit and scope of the present invention, and such modifications, changes and additions should be regarded as belonging to the following claims.

P1: shear reduction force value P2: trailing force reduction value
T2: Input tension value T3: Medium tension value
T4: Surveying tension value T2 _ref : Target landing tension value
T3 _ref : Target intermediate tension value T4 _ref : Target starting tension value
MS0, MS1, MS2: Master Speed Value εt: Design Elongation
K: Abkhabi 1: Steel Plate
110: entrance bridal roll 120: shear rolling mill
130: after rolling mill 140: exit bridal roll
121: entry tension control unit 131: intermediate tension control unit
141: tension control unit

Claims (7)

In the steel sheet elongation control device of a two-stand rolling mill, the entry bridle roll, the shear rolling mill, the rear end rolling mill and the exit bridle roll are connected in sequence, and the entry bridle roll is driven at the master speed value MS0.
The roll speed of the shear rolling mill is controlled to receive a master speed value MS0, and feed back the measured side tension value T2 measured on the steel sheet passing through the side bridal roll to follow a target side tension value T2 _ref . An entrance tension control unit 121;
The master speed value MS1 calculated by the following equation (1) is input, and the intermediate tension value T3 measured in the steel sheet passing through the shear rolling mill is fed back to follow the target intermediate tension value T3 _ref . Medium tension control unit 131 for controlling the roll speed of the after mill
MS1 = MS0 · [1+ K / (K + 1)] · εt equation (1)
(Where K is P1 / P2, P1 is the shear reduction force value of the shear mill, P2 is the trailing force force value of the trailing mill, and εt is the design elongation of the steel sheet);
The master speed value MS2 calculated by the following equation (2) is input, and the feed back tension value T4 measured in the steel sheet passing through the post rolling mill is fed back to follow the target outgoing tension value T42 _ref . Exit tension control unit 141 for controlling the speed of the exit bridal roll
MS2 = MS1 [1 + 1 / (K + 1)] εt equation (2);
Steel sheet elongation control device of a two-stand rolling mill, characterized in that it comprises a. The method of claim 1,
The shear reduction force value (P1) is set to the maximum reduction force value of the shear rolling mill, steel sheet elongation control device of a two-stand rolling mill. According to claim 1, wherein the entry tension control unit 121
An entry tension control device 122 for calculating a difference value between the entry tension value T2 and a target entry tension value T2 _ref ;
A second speed control device (123) for calculating a compensation master speed value (MS0 ') of the master speed value (MS0) corresponding to the difference value as a backup roll drive motor speed of the shear rolling mill; And
And a second current control device (124) for calculating a drive current value of the backup roll drive motor corresponding to the speed of the backup roll drive motor. The method of claim 1, wherein the intermediate tension control unit 131 is
An intermediate tension control device 132 for calculating a difference value between the intermediate tension value T3 and a target intermediate tension value T3 _ref ;
A third speed control device (133) for calculating a compensation master speed value (MS1 ') of the master speed value (MS1) corresponding to the difference value as a backup roll driving motor speed of the rear end rolling mill; And
And a third current control device (134) for calculating a drive current value of the backup roll drive motor corresponding to the backup roll drive motor speed. The method of claim 1, wherein the exit tension control unit 141
A measurement tension control device (142) for calculating a difference value between the measurement tension value (T4) and a target measurement tension value (T4 _ref );
A fourth speed control device (143) for calculating a compensation master speed value (MS2 ') of the master speed value (MS2) corresponding to the difference value as a drive motor speed of the exit bridal roll; And
And a fourth current control device 144 for calculating a drive current value of the exiting bridal roll drive motor corresponding to the drive motor speed of the exiting bridle roll. . In the method of controlling the steel sheet elongation of a two-stand rolling mill, in which the entrance bridle roll, the shear rolling mill, the rear end rolling mill, and the exit bridal roll are connected in sequence,
(a) driving the entrance bridal roll to a master speed value MS0;
(b) driving the roll of the shear rolling mill by feeding back the input tension value T2 measured in the steel sheet passing through the entrance bridle roll to compensate the master speed value MS0;
(c) feeding back the intermediate tension value T3 measured in the steel sheet passing through the shear rolling mill, and compensating the master speed value MS1 calculated by Equation (1) to drive the roll of the post rolling mill;
MS1 = MS0 · [1+ K / (K + 1)] · εt equation (1)
(Where K is P1 / P2, P1 is the shear reduction force value of the shear mill, P2 is the trailing force force value of the trailing mill, and εt is the design elongation of the steel sheet); And
(d) driving the exit bridal roll by feeding back the exit tension value T4 measured in the steel sheet passing through the rear end rolling mill to compensate the master speed value MS2 calculated by Equation (2) below;
MS2 = MS1 · [1 + 1 / (K + 1)] · εt equation (2)
Steel sheet elongation control method of a two-stand rolling mill, characterized in that it comprises a. The method of claim 6,
The shear reduction force value (P1) is set to the maximum reduction force value of the shear rolling mill, steel sheet elongation control method of a two-stand rolling mill.

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