KR20020051075A - Width control apparatus of rolling strip by compensating roll gap and its method in hot strip mill - Google Patents

Abstract

PURPOSE: An apparatus and a method for controlling width of a strip in a hot finish rolling mill through roll gap compensation are provided to control a width error due to a difference between an actually measured width and a target width in the hot finish rolling mill by compensating a roll gap of a stand preceding to a final stand. CONSTITUTION: The apparatus for controlling width of a strip in a hot finish rolling mill through roll gap compensation comprises a data collection unit(11) collecting data including roll force and actually measured widths; an SCC(supervisory control computer) setting unit(10) impressing a target width for comparison with the actually measured widths; a width comparison unit(12) obtaining a difference between the actually measured widths and a target width; a microprocessor unit(13) performing calculation and judgement processing required for obtaining a roll force gain from the difference between the actually measured widths and the target width; and a gain output unit(14) compensating the roll gap through a hydraulic cylinder(7) controlling a roll gap of the preceding stand by supplying roll force AGC(automatic gauge controller) gains to a roll force AGC(automatic gauge controller)(15).

Description

Width control apparatus of rolling strip by compensating roll gap by compensating roll gap and its method in hot strip mill}

The present invention relates to an apparatus and method for hot finishing rolling width, and more particularly, to a width error due to a difference between a target width and a signal from a width gauge installed at the last stand exit when performing width control in hot finishing rolling. An apparatus and method for controlling width by compensating for a roll gap of a previous stand.

By controlling the current of the rolling mill's main motor against the dimensional quality deviation of the coil tip and the rolling sheet unstable factor in the hot rolling, the distal end of the main motor system is eliminated when the plate passes through the stand. It is essential that the technology to prevent the occurrence of miss roll occurring in the steel sheet, to eliminate the chronic quality defects of the hot rolled products (the tip dimensional defect) and to improve the control instability in finishing rolling to obtain the best hot rolled quality to be.

1 schematically shows a hot rolling controller according to the prior art. As shown in FIG. 1, the looper located between each adjacent rolling roll 1 consists of a looper roll 3 and a looper arm 4, and serves to keep the tension of the strip 2 constant. In general, the looper measures the speed of the main motor in order to measure the looper angle and reduce the error from the target angle through the height controller.

The control method first detects the looper angle θ and feeds it back to the looper drive system 6, that is, the looper motor for rotating the looper arm 4, so that the detected looper angle θ is adjusted to the target angle. The detected looper angle [theta] is calculated through the height controller and the rotation speed target value is input to the stand main motor No. 6 to control the rotation speed of the main motor to control the rotation speed of the rolling roll 1.

At this time, the looper drive system 6 is a current that causes the strip 2 to be driven from the I stand (stand 6 here) to the I + 1 stand (stand 7 here) and moves the looper drive 6 after 0.1 second. Drive in about 0.6 seconds and control starts according to the output of the looper's height controller (PI controller). However, after about 0.2 to 0.3 seconds the looper is in operation and the looper touches the strip 2. In the drawings, reference numeral 5 denotes a load measuring sensor, 8 denotes a stand hydraulic cylinder No. 7, and 15 denotes a roll force automatic gauge controller (AGC).

However, no device has been developed for controlling the difference between the actual width and the target width using the width gauge 9 on the exit side of the last stand (here, stand 7) for width control.

Conventional rolling width control related technology related to the present invention, Japanese Patent Laid-Open No. 57-44410 (Hot Rolling Width Control Device-Samreung Electric Co., Ltd.), Japanese Patent Laid-Open No. 58-58915 (Control device of continuous rolling mill-Samreung Electric Co., Ltd.) and Japanese Patent Application Laid-Open No. 03-323292 (Method of controlling the width of a continuous sheet rolling machine-New Nippon Steel Co., Ltd.), and these techniques have the following problems.

First of all, the above-mentioned techniques constitute a device for controlling the speed of the front end stand by installing a width gauge between the stands for the finishing rolling width control, but the width gauge between the stands is expensive and the width is measured by using three CCD cameras. In consideration of the distance between the stand (5.5m), there is a problem that the control time is insufficient to process the measured width and feed back to the main motor of the front end stand.

Second, the looper current control (tension control) is performed between the front end stands by calculating the error from the target width by using the exit width meter. For this reason, it is a technology that cannot be implemented in factories with various steel grades and sizes (for example, Pohang two hot rolling).

Therefore, the present invention has been made to solve the problems of the prior art as described above, when the width control is performed in hot finishing rolling, the difference between the signal and the target width from the width gauge installed on the last stand exit side. It is an object of the present invention to provide an apparatus and a method capable of ultimately controlling the width by compensating the roll gap of the previous stand by the width error caused by the width error.

1 is a schematic diagram of a hot rolling controller according to the prior art,

2 is a flowchart illustrating a method for controlling hot rolling width through roll gap compensation according to the present invention;

3 is a schematic diagram of a hot finishing rolling width control apparatus through roll gap compensation according to the present invention.

♠ Explanation of symbols on the main parts of the drawing ♠

1: Upper finishing rolling roll 2: Strip

3: looper roll 4: looper arm

5: load measurement sensor 6: looper driver

7: No.6 Stand Hydraulic Cylinder 8: No.7 Stand Hydraulic Cylinder

9: Exit measuring meter 10: SCC setting device

11: data acquisition device 12: target width and actual width comparison device

13 microprocessor device 14 gain output device

15: roll force AGC

The apparatus of the present invention for achieving the above object is to control the width by compensating the roll gap of the previous stand of the final stand of the width error due to the difference between the actual width and the target width in hot finishing rolling. The apparatus includes a data collection device for collecting data including a rolling load and a measured width, a supervisory control computer (SCC) setting device for applying a target width for comparison with the measured width, and the measured width and the target width. A width comparator for obtaining a difference between the microprocessor and a microprocessor device for performing a calculation and a determination process for calculating a roll force gain from the difference between the measured width and the target width, and a roll force AGC (Automatic Gauge Controller) A gain output device for supplying gain to the roll force AGC to compensate through a hydraulic cylinder controlling the roll gap of the previous stand.

Further, the method of the present invention is to control the width by compensating for the roll gap of the previous stand of the exit stand by the width error caused by the difference between the measured width and the target width in hot finishing rolling. This method collects the rolling load to determine whether the rolled plate is metal in the final stand, and collects the measured width by detecting the width of the rolled plate discharged through the exit of the final stand when the rolled plate is inserted. Calculating a difference between the measured width and the target width already set up; and if the measured width is larger than the target width, reduce the roll force AGC (roll force automatic gauge controller) gain of the previous stand to reduce the roll gap. If the reduction is small, the gain may be increased to increase the lob gap, and determining whether the rolled plate is pulled out of the final stand.

In the following, with reference to the accompanying drawings, a preferred embodiment of the hot finishing rolling width control apparatus and the method through the roll gap compensation according to the present invention will be described in detail.

2 is a flowchart illustrating a method for controlling hot rolling width through roll gap compensation according to the present invention.

As shown in Figure 2, the width control method of the present invention is composed of the following algorithm. First, in the first step (S1) to determine whether the plate is indented (Metal in) from the load measuring sensor (5) installed on the seventh stand (7) if the plate is inserted (Yes) and performs the second step. In the second step S2, a setup value such as a target width Wr set according to each rolling condition is read from the supervisory control computer (SCC) setting device 10. In the third step S3, the measured width is read from the data collecting device 11. This measured width is read by an analog signal from the exiting width gauge 9 at the end of the last stand. The data collecting device 11 is a device for collecting a load and an exit width measured value for determining whether a plate is inserted into the stand # 7.

In the fourth step S4, the difference is obtained by the comparison device 12 which obtains the difference between the target width and the measured width read in the second step S2 and the third step S3. In the fifth, sixth, and seventh steps S5, S6, and S7, if the measured width W is the target width (D) in the difference between the measured width W and the target width Wr obtained in the fourth step S4. If larger than (Wr) (ex), the tension between the 6 stands and 7 stands is greatly increased so that the measured width (W) is reduced. In order to increase the tension, the present invention commands to reduce the gain of the roll force AGC (15; Roll Force Automatic Gauge Controller) of the sixth stand. This is because the algorithm of the roll force AGC 15 has a structure as shown in Equation 1 below.

Here, ΔS represents a roll gap deviation, α represents a roll force gain, ΔP represents a rolling load variation, M represents a rolling mill stiffness coefficient, and Δh represents an exit thickness deviation.

Therefore, if the roll force gain α is reduced, the roll gap of the sixth stand is reduced to increase the tension to match the target width Wr.

On the contrary, on the contrary, if the measured width W is smaller than the target width Wr (no), a width defect occurs. In this case, a control for reducing tension is required, so that the roll gap is increased by increasing the roll force AGC gain. Control is required.

In the eighth step S8, a gain output device 14 for outputting the control gain of the roll force AGC obtained in the sixth and seventh steps S6 and S7 to the AGC is passed. In the ninth step S9, if the rolled plate is out (Metal out) of the stand No. 7 (Yes), otherwise (No), a loop is returned to the third step S3.

3 is a schematic diagram of a hot finishing rolling width control apparatus through roll gap compensation according to the present invention.

As shown in FIG. 3, the width control apparatus of the present invention collects data such as rolling load and measured width W, which are necessary in the first step S1 and the third step S3 of FIG. 2. ), The supervisory control computer (SCC) setting device 10 for applying a target width Wr for comparison with the actual measurement width W required in the second step S2, and the actual measurement of the fourth step S4. Calculation and determination processing required in the target width and actual width comparing device 12 and the fifth, sixth, and seventh steps S5, S6, and S7 for obtaining the difference between the width W and the target width Wr are performed. It includes a microprocessor device 13 that can be performed. And a gain output device 14 capable of outputting the roll force AGC gain obtained in the eighth step S8, and a roll force AGC 15. In FIG. 3, reference numeral 6 denotes a looper driver. Denotes a sixth stand hydraulic cylinder, and 8 represents a seventh stand hydraulic cylinder.

As described in detail above, the hot finishing rolling width control apparatus and the method using the roll gap compensation of the present invention transfer the width error due to the difference between the actual width and the target width from the width gauge installed at the exit of the last stand of the finishing rolling. The width is controlled by compensating for the roll gap of the stand.

In the above description, the technical description of the hot finishing rolling width control apparatus and its method through the roll gap compensation of the present invention has been described together with the accompanying drawings, which illustrate the best embodiment of the present invention by way of example. no.

In addition, it is obvious that any person skilled in the art can make various modifications and imitations without departing from the scope of the technical idea of the present invention.

Claims (2)

In the apparatus for controlling the width by compensating the roll gap of the previous stand of the final stand in the width error due to the difference between the measured width and the target width in hot finishing rolling, A data collection device for collecting data including a rolling load and a measured width, a supervisory control computer (SCC) setting device for applying a target width for comparison with the measured width, and a difference between the measured width and the target width A roll comparator, a microprocessor device for performing calculation and determination processing necessary to obtain a roll force gain from a difference between the measured width and the target width, and a roll force AGC (Automatic Gauge Controller) roll And a gain output device for supplying a force AGC to compensate through a hydraulic cylinder for controlling the roll gap of the previous stand. In the method of controlling the width by compensating the roll gap of the previous stand of the exit stand in the width error due to the difference between the measured width and the target width in hot finishing rolling, Determining whether the rolled plate is metal in the final stand by collecting the rolling load; and collecting the measured width by sensing the width of the rolled plate discharged through the exit of the final stand when the rolled plate is inserted; Obtaining the difference between the actual width and the target width already set up; if the actual width is larger than the target width, reduce the roll force AGC (roll force automatic gauge controller) gain of the previous stand to reduce the roll gap; And increasing the gain to increase the lob gap, and determining whether the rolled plate is pulled out of the final stand.