JPH08215730A - Roll bending equipment and plate rolling method of plate rolling mill - Google Patents

Abstract

PURPOSE: To provide the steel plate of thickness and flatness with excellent precision by providing servo valves on housing posts on the inlet and outlet sides of the driving side and the operation side of the rolling mill, and setting the length of the hydraulic piping to a bender cylinder below the prescribed value. CONSTITUTION: Servo valves 1-4 for controlling the roll bending pressure are provided on housing posts on the inlet and outlet sides of the roll stock on the driving side and the operation side, and the piping is provided to project blocks 5-8 where hydraulic cylinders of the roll bending equipment are built in. The working fluid is forcibly fed from the hydraulic source by the piping 11, and the piping is branched to the pipings 12, 13, and further branched to the pipings leading to the project blocks 5, 7 and 6, 8. Because the servo valves 1-4 can control the difference between the hydraulic pressure on the increase side and the hydraulic pressure on the decrease side individually to allow the simple structure of the piping, the length of the secondary piping of the servo valves 1-4 to control the response characteristics of the bender can be reduced within 2m, and a highly responsive bending roll equipment of >=10Hz can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roll bending apparatus of a rolling mill for controlling the sectional shape and flatness of a rolled sheet material, and particularly to a roll suitable for a sheet rolling machine equipped with hydraulic reduction as a rolling down apparatus. The present invention relates to a bending device and a rolling method thereof.

[0002]

2. Description of the Related Art A sheet rolling machine is equipped with a roll bending device for the purpose of controlling the sectional shape and flatness of a rolled material. The bending force of these bending devices is adjusted by controlling the hydraulic pressure. In order to control this hydraulic pressure, hydraulic control valves are used individually for the increment side and the decrease side, respectively, and are placed in the underground oil cellar room and the upper part of the rolling mill in consideration of the valve base installation space and maintainability. It was

Since this hydraulic control valve was not a high response servo control valve but a normal hydraulic control valve, it could only achieve a response of 1 Hz or less at a control response frequency of 90 ° phase delay, but the plate thickness Since the pressure reducing device for control is not used in the high response region, there was no problem in practical use (hereinafter, the control response frequency has a phase delay of 90 degrees).

[0004]

However, in recent years, in order to realize highly accurate plate thickness control, a highly responsive hydraulic pressure reducing device is used as a pressure reducing device, and the plate thickness control and the plate controlling are also used in the control technique. There has been an increasing demand for realizing non-interference control with respect to cross-sectional shape and flatness control. However, even if a hydraulic pressure reduction having a high response of 10 Hz or more is applied as the pressure reduction device, if the response of the bending device is as low as about 1 Hz, the shape of the plate due to the load fluctuation that occurs when the hydraulic pressure reduction is used with high response There is a problem that changes (ear waves, middle stretch) cannot be corrected, and as a result, the performance of the hydraulic pressure reducing device cannot be fully utilized, that is, high-precision plate thickness control cannot be realized.

This problem is particularly noticeable when the leading edge of the plate is threaded. That is, in order to correct the finishing reduction setting calculation error, the larger the hydraulic pressure reduction moves at an earlier timing, the more the shape of the strip at the plate tip changes, and the narrowing of the strip at the self stand (misroll) or the next stand. Therefore, it is possible to delay the operation timing of high-response hydraulic pressure reduction by avoiding the unsteady part, or to reduce the scale factor (actual control correction amount / theoretical necessary correction amount) of the automatic plate thickness control to reduce rolling. Will be done. Therefore, it is difficult to perform highly accurate plate thickness control over the entire length of the threaded plate.

As a countermeasure for this, as shown in FIG. 5, a servo control valve is used as a hydraulic control valve of the bending device,
A servo valve dedicated to the increment side and dedicated to the decrease side was used to operate the four hydraulic cylinders of each housing post. FIG. 3 shows a case in which this servo valve is installed above the rolling mill. Even with this method, since it is installed on the upper part of the rolling mill where the rolling-down device, various wirings, pipes, etc. are complicated, there is a restriction on the installation location, and one servo valve operates the four hydraulic cylinders of each housing post. Therefore, in order to keep the operating speed constant, there is no choice but to adjust the other pipe length to the longest pipe distance at the four locations.
As a result, the pipe length becomes about 7 m, so 5-6
Only a response of about Hz could be realized, and it was not sufficient to demonstrate the performance of high response hydraulic pressure reduction.

Therefore, the present invention has been devised to solve such a problem, and provides a roll bending apparatus and a rolling method therefor capable of realizing high-accuracy simultaneous control of sheet thickness and flatness in sheet rolling. It was made for the purpose of doing.

[0008]

SUMMARY OF THE INVENTION In order to achieve the object, a plate rolling mill roll bending apparatus of the present invention has a servo control capable of controlling a difference between a hydraulic pressure on the increment side and a hydraulic pressure on the decrease side. These servo valves are installed on the side of the housing post at a total of four inlet and outlet sides on the drive side and the operating side of the rolling mill housing, from each servo valve to the bender cylinder. The rolling mill roll bending apparatus is characterized in that the length of the hydraulic pipe is within 2 m.

Further, the sheet rolling mill bending apparatus of the present invention is installed in a rolling mill equipped with a hydraulic pressure reduction device, and a sheet rolling method characterized by the following is carried out to obtain highly precise sheet thickness and flatness. Simultaneous control is possible. (1) A strip rolling method characterized in that simultaneous control of strip thickness and flatness is started within 0.3 seconds after the strip tip portion is caught in the rolling mill. (2) A plate rolling method, wherein a scale factor of automatic plate thickness control of the rolling mill is set to 0.9 or more, and the plate thickness and flatness are simultaneously controlled. (3) As a control method of the rolling mill, the above (1)
Alternatively, a plate rolling method is characterized in that the rolling method of (2) is carried out at the same time.

[0010]

The present invention will be described in detail below. INDUSTRIAL APPLICABILITY The present invention applies a servo valve capable of controlling the pressure difference between the hydraulic pressure on the increase side and the hydraulic pressure on the decrease side, and the servo valves individually installed for the conventional hydraulic pressure on the increase side and the hydraulic pressure on the decrease side. By halving the number of valves and drastically reducing the space required to install the valve seat, it is possible to install servo valves on four sides of the rolling mill housing where it is difficult to secure space for equipment installation, and to reduce the number of roll bending devices. By setting the length of the next pipe to be within 2 m, a roll bending device having a characteristic of high frequency response of 10 Hz or more as shown in Fig. 1 was realized. Furthermore, from the servo valves installed at the four sides of the rolling mill housing (the operating side inlet / outlet side and the drive side inlet / outlet side) to the working cylinders of the bending machine installed in the project block in the rolling mill. Since a hydraulic circuit having substantially the same pipe length, pipe diameter, and bend points can be realized, the same response characteristics can be imparted to the working cylinders of the four bending devices.

By applying the roll bending apparatus of the present invention capable of operating all the working cylinders of the stand of the roll bending apparatus of the plate rolling mill with the same response and with the high responsiveness equivalent to that of the hydraulic pressure reducing apparatus, the roll bending force can be rapidly increased. In addition, stable bending control can be performed even in the transitional period when the front and rear ends of the rolled material that need to be significantly changed can be obtained, and a desired flatness can be obtained.

The roll bending apparatus of the present invention will be specifically described below with reference to the drawings. FIG. 2 shows an embodiment of the device of the present invention, in which 1 to 4 (4 is not shown) are the inlet side and the outlet side of the rolled material on the operating side and the inlet side and the outlet side of the rolled material on the driving side. It is a servo valve for roll bending pressure control installed in the housing of. 5 to 8 (8 is not shown) are project blocks containing hydraulically actuated cylinders of the roll bending apparatus. Further, 9 and 10 are mill housings on the operating side and the driving side. The hydraulic oil pumped from a hydraulic source through a single pipe 11 is branched into an operation-side pipe 12 and a drive-side pipe 13 at the upper part of the rolling mill. Further, on the operating side and the driving side, the pipes are branched to the inflow side defect blocks 5 and 7 and the outflow side project blocks 6 and 8 of the rolled material, respectively.

As shown in the control block diagram of FIG. 4, the servo valve installed immediately before the hydraulically actuated cylinder built into each project block uses one servo valve for the difference between the hydraulic pressure on the increment side and the hydraulic pressure on the decrease side. Since it has a controllable function, the servo valve body and the piping between the servo valve and the hydraulically actuated cylinder can have a simple structure and can be installed on the side surface of the housing, which requires less space for equipment installation.

As a result, the secondary piping length of the servo valve that determines the response characteristics of the bender can be shortened to within 2 m.
As shown in, a high response roll bending device with a frequency of 10 Hz or higher can be realized. In addition, since the piping path from each servo valve to the hydraulically actuated cylinder is installed in each housing, it is possible to easily make the piping length uniform and to make the pressure response characteristics of each hydraulically actuated cylinder the same. Easy to implement. Further, even if it is necessary to make a difference in roll bending force between the driving side and the operating side or to make a difference in bending force between the inlet side and the outlet side in response to the difference in mill rigidity between the driving side and the operating side, the roll of the present invention The bending device can also be independently controlled for each hydraulically actuated cylinder, and any roll bending method can be adopted. The reason for setting the secondary piping length of the servo valve within 2 m was set for the purpose of ensuring the response of the roll bending device as well as the hydraulic pressure reducing device because the response of the current hydraulic pressure reducing device is 10 Hz or more.

Further, when the roll bending apparatus of the present invention is applied to a rolling mill equipped with a hydraulic pressure reducing device as a pressure reducing device, the high performance of the hydraulic pressure reducing device can be sufficiently exhibited, and the plate thickness and plate flatness with high accuracy can be obtained. The simultaneous control of can be realized for the first time. The present inventors have clarified that the conventional roll bending device has a control response of 1 to 6 Hz, which is less than half of the control response of the hydraulic pressure reduction device, and therefore has the following problems.

(1) At the time of passing the plate leading end, the more the hydraulic pressure reduction moves at an earlier operation timing in order to correct the finishing reduction setting calculation error, the more the shape of the plate leading end changes greatly.
Since it leads to the narrowing (miss roll) of the threading material at its own stand or the next stand, avoiding the unsteady part, the operation timing under high hydraulic pressure response (starting timing of automatic thickness control) after biting the tip of the plate Delayed by 1 to 2.5 seconds. For this reason, as shown in FIG. 6, the plate thickness defective portion at the plate tip portion continues for a long time, and it is difficult to obtain good plate thickness accuracy over the entire length.

(2) In the case of the conventional low-response roll bending apparatus, the greater the amount of hydraulic pressure reduction when the front end of the plate is engaged, the greater the amount of change in rolling load.
Since the change in the bending of the roll also becomes large, the shape of the threaded plate is greatly disturbed, leading to narrowing (miss roll). For this reason, the scale factor (correction amount of actual control / theoretical necessary correction amount) of automatic plate thickness control is reduced to a small value, and as shown in FIG. 6, it is difficult to correct the plate thickness defect part at the plate tip. ,
It is difficult to obtain good plate thickness accuracy over the entire length.
In particular, for high-tensile steel plates that are difficult to roll and thin products with a plate thickness of 2 mm or less, the scale factor for automatic plate thickness control is 0.4 to 0.
The current situation is that only about 7 are obtained.

The plate rolling method of the present invention is applied to a rolling mill equipped with a hydraulic reduction device, in order to solve the problems of the conventional automatic plate thickness control, the high response roll bending device of the present invention is applied. By applying the following plate rolling method, the plate thickness accuracy and plate flatness were dramatically improved.

(1) Simultaneous control of automatic plate thickness control by hydraulic reduction and flatness control by the roll bending apparatus of the present invention is started within 0.3 seconds after biting of the plate tip into the rolling mill. Thus, a more accurate plate thickness and a predetermined flatness can be obtained from the plate tip portion. The reason for setting the time within 0.3 seconds is to suppress the non-control area to within about 3.5 m of the plate front end because the rolling speed of the plate front end of the rolled material is about 700 mpm. Since this portion is the innermost winding portion of the subsequent coil winding machine and is a portion to be removed by the winding segment mark or the like, there is no actual harm in use.

(2) In the case of the rolling mill having a roll bending device with a high response as well as a hydraulic pressure reducing device, the scale factor of the automatic plate thickness control (correction amount of actual control / theoretical necessary correction amount) is not more than 2 mm. Even if it is 0.9 or more including thin materials, the pressure of the roll bending device is adjusted so as to cancel the roll deflection change due to the abrupt load change caused by the large amount of hydraulic pressure reduction toward the target plate thickness due to the finish reduction setting calculation error. Since the control can be performed with high response, it is possible to obtain a highly accurate plate thickness and a predetermined flatness without disturbing the passing plate shape. More specifically, for example, when the finish rolling setting calculation is slightly thicker at the plate tip portion, the hydraulic rolling rapidly tightens the rolling toward the target plate thickness, so that the rolling load increases. As the rolling load increases, the bending of the roll increases, so that the both ends of the threaded plate change into a wavy end wave shape. To cancel this, if the roll bending device is quickly operated to the decrease bending side by the amount of change in rolling load, rolling can be performed without changing the rolling shape from the plate tip, which was a problem in conventional operation. The hydraulic pressure is large,
It is possible to solve the problem of the drawing of the rolling mill caused by the rapid operation, bring out the original performance of hydraulic pressure reduction, and obtain a highly accurate strip thickness.

(3) A plate rolling method for simultaneously carrying out the rolling methods of (1) and (2) described above, that is, within 0.3 seconds from the biting of the plate front end and the automatic plate thickness control scale. If the factor is 0.9 or more, the automatic plate thickness control by hydraulic pressure reduction and the automatic flatness control by the roll bending device are started at the same time, and the plate total length is controlled, so that the plate thickness and flatness with higher accuracy can be secured. FIG. 7 shows the control result.

Further, the rolling mill to which the highly responsive roll bending apparatus of the present invention is applied is preferably the final stage of the finishing rolling mill. If the finishing setting calculation error is excessive and the correction amount of the hydraulic reduction is insufficient with only the final one stand, the number of applicable stands may be increased upstream according to the finishing setting calculation error.

[0023]

EXAMPLE In the roll bending apparatus shown in FIGS. 2 and 4, the control of the bending force is performed through servo valves capable of controlling the difference between the hydraulic pressure on the increase side and the hydraulic pressure on the decrease side, and these servo valves are rolled. It is placed on the side of the housing post at a total of 4 places on the inlet side and the outlet side of the machine's housing, the inlet side and the outlet side, and the length of the hydraulic pipe from each servo valve to the bender cylinder is 1.5 m, and 12 Hz Got a control response.

The above-mentioned roll bending device was incorporated into the third stand of the finishing stand of the finishing stand of the hot strip rolling mill having the hydraulic pressure reducing device, and the thickness and flatness of the plate were adjusted in 0.2 seconds from the tip of the plate. Simultaneous control was performed. Rolling material is 490MPa high-strength steel, which is difficult to roll, thickness 1.8mm, width 100
Performance evaluation of the plate thickness accuracy was performed with 0 mm material.

The number of rollings in each case is 50, and the average value is shown in Table 1. Case 1 is a case where the scale factor of automatic plate thickness control is 0.7.

Case 2 is a case where the scale factor of the automatic plate thickness control is 0.95. For further comparison,
Using the conventional roll bending device (control response 2Hz at a distance of 18m from the servo valve to the bender cylinder) before improvement, automatic thickness control (AGC) is applied to the plate tip without simultaneous control of plate thickness and flatness. The case where the scale factor of automatic plate thickness control is set to 0.4 starting from 2.5 seconds after biting is shown.

The high-response roll bending apparatus of the present invention is applied to a sheet rolling machine having a hydraulic pressure reduction device, and simultaneous control of automatic sheet thickness control and automatic flatness control, which is the rolling method of the present invention, is applied to the rolling machine. Starting from 0.2 seconds after biting into the plate tip, control over the entire length of the plate, and by setting the scale factor of automatic plate thickness control to 0.95, the high-tensile thin material of difficult-to-roll material can be rolled over the entire length of the rolled material. The target plate thickness can be controlled within a range of 99% to ± 50μ, and good plate flatness was also obtained.

[0028]

[Table 1]

[0029]

As described above, the roll bending apparatus of the present invention uses the servo valve having the function of controlling the difference between the hydraulic pressure on the increment side and the hydraulic pressure on the decrease side, and the The hydraulic piping has been simplified and can be installed on the side of the rolling mill housing with a narrow space, and the secondary piping distance between the servo valve and the working cylinder has been shortened to within 2m. As a result,
It is possible to control with a high response exceeding 10 Hz and it is easy to make the pressure characteristics of the four working cylinders the same. Also,
The bending pressure on the operating side and the driving side can be positively and independently changed, and the bending pressure at the tip of the plate, the one-sided wave and the one-sided expansion of the plate can also be applied.

The roll bending device of the present invention is applied to a plate rolling machine equipped with a hydraulic pressure reducing device, and automatic plate thickness control by the hydraulic pressure reducing device and automatic flatness control by the high response roll bending device are performed as the plate rolling method of the present invention. Simultaneously starting within 0.3 seconds from the biting of the plate tip into the rolling mill and controlling over the entire length of the plate, accidents such as drawing of the rolling mill can be prevented and good plate thickness and plate flatness can be obtained. Obtainable. Furthermore, by setting the scale factor of the automatic plate thickness control to 0.9 or more, the original performance of the hydraulic pressure reducing device can be brought out, and it becomes possible to manufacture a steel plate having a high plate thickness accuracy and a good plate flatness.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a relationship between a secondary pipe length from a servo valve to a bender working cylinder and a frequency response.

FIG. 2 is an arrangement diagram of servo valves in an embodiment of a roll bending apparatus to which the present invention is applied.

FIG. 3 is a servo valve layout diagram of an example of a conventional roll bending apparatus.

FIG. 4 is a control block diagram of an embodiment of the present invention.

FIG. 5 is a control block diagram in a conventional bending device.

FIG. 6 is a plate thickness behavior in the conventional automatic plate thickness control.

FIG. 7 is a plate thickness behavior to which the rolling method of the present invention is applied.

[Explanation of symbols]

1 Servo valve capable of pressure difference control (operation side inlet side) 2 Servo valve capable of pressure difference control (operation side outlet side) 3 Servo valve capable of pressure difference control (drive side inlet side) 5 Project block (operation) Side input side) 6 project block (operating side output side) 7 project block (drive side input side) 9 rolling mill housing (operating side) 10 rolling mill housing (drive side) 11 main hydraulic pressure from hydraulic source Pipes 12 Branched hydraulic pipes (operation side) 12-1 Branched hydraulic pipes (for operation side increment) 12-2 Branched hydraulic pipes (for operation side decrease) 13 Branched hydraulic pipes (drive) Side) 13-1 branched hydraulic piping (for drive side increment) 13-2 branched hydraulic piping (for drive side decrease) 14 absolute pressure controllable servo valve (dedicated to incremental) 5 Absolute pressure controllable servo valve (Decrease only) INC Increase hydraulic piping DEC Decrease hydraulic piping TWR Upper work roll BWR Lower work roll SV Servo valve PC Pressure sensor SAMP Servo amplifier ΔPW Bender Differential pressure (operating side) ΔPD Bender Differential pressure (drive side) PINC Bender pressure (for increment) PDEC Bender pressure (for decrease)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B21B 37/18 8315-4E B21B 37/12 111A (72) Inventor Masami Tobata-ku, Kitakyushu, Fukuoka No. 1 Tobitacho New Steel Works Yawata Works

Claims (4)

[Claims] 1. A roll bending apparatus for a rolling mill for controlling the cross-sectional shape and flatness of a rolled sheet material, the bending force is controlled by a servo valve capable of controlling the difference between the hydraulic pressure on the increase side and the hydraulic pressure on the decrease side. These servo valves are arranged on the side of the housing post at a total of four inlet and outlet sides on the drive side and operating side of the rolling mill housing, and hydraulic pipes from each servo valve to the bender cylinder are installed. The plate bending machine roll bending apparatus is characterized in that the length is within 2 m. 2. A plate rolling method using a rolling mill comprising the plate rolling mill roll bending apparatus according to claim 1 and a hydraulic pressure reducing apparatus as a rolling down apparatus, wherein the leading end portion of the sheet rolling into the rolling machine is set to 0. A plate rolling method, wherein simultaneous control of plate thickness and flatness is started within 3 seconds. 3. A sheet rolling method using a rolling mill comprising the sheet rolling mill roll bending apparatus according to claim 1 and a hydraulic rolling down apparatus as a rolling down apparatus, wherein a scale factor of automatic sheet thickness control is 0.9 or more, A sheet rolling method characterized by simultaneously controlling sheet thickness and flatness. 4. A sheet rolling method using a sheet rolling mill roll bending apparatus according to claim 1, and a rolling mill equipped with a hydraulic pressure reduction apparatus as a reduction apparatus, wherein a scale factor for automatic sheet thickness control is 0.9 or more, A plate rolling method, wherein simultaneous control of the plate thickness and the flatness is started within 0.3 seconds after the leading end of the plate is bitten into the rolling mill.