JPH08108206A - Rolling mill for executing constant-pressure screw-down control, method for detecting amount of meandering and method for controlling meandering in pinch roll - Google Patents

Abstract

PURPOSE: To prevent meandering with pinch rolls by taking the time depending variables of the detected values of roll gaps on the work and drive sides as a parameter to the amount of meandering and correcting rolling force so as to make the variables zero. CONSTITUTION: Bearing boxes 7 for supporting a lower buck-up roll 5 are in contact with screw-up cylinders 8, 9 on the work and drive sides. The moving amounts of these screw-up cylinders 8, 9 on the work and drive sides age detected with roll gap detectors 14, 15 on the work and drive sides and transmitted to a host CPU 16 as the detected values δ of roll gaps. In the host CPU 16, the detected values are converted into the time depending variables Δδ/Δt and converted into leveling forces Ft. Further, the leveling forces Ft are added to the rolling forces P on the work and drive sides before meandering and corrected rolling force directing signals are transmitted to rolling force setting devices 17, 18 on the work and drive sides so that the time depending variables Δδ/Δt become zero. In the above-mentioned manner, corrected rolling forces are added to the screw-up cylinders 8, 9 on the work and drive sides and meandering is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting a meandering amount and a meandering control method for a rolling mill and a pinch roll for performing constant pressure reduction control.

[0002]

2. Description of the Related Art Conventionally, various methods of detecting the amount of meandering have been proposed and implemented in order to suppress the meandering of material generated in rolling mills, pinch rolls and the like.

For example, as described in Japanese Patent Laid-Open No. 20608/1990 as a method for detecting the off-center amount of the material on the inlet / outlet side of the rolling mill, the amount of movement of the end position of the material is determined by using an optical sensor. Is being detected.
Similarly, as a method of detecting the off-center amount of a material, Japanese Patent Laid-Open No. 59-85314 discloses a method of pressing the work side (hereinafter referred to as WS) / drive side (hereinafter referred to as DS) end side of the material with a vertical pressing roll. Has been described. This press roll is horizontally movable and its position is supported by a spring.When the material meanders, the material end presses the press roll, and the force compresses the spring.
It has a structure that moves to the opposite side of the material. A position displacement detector is attached to the press roll, and a detection method for detecting the displacement amount as a parameter of the meandering amount has been proposed.

Further, JP-A-57-112920 discloses a method of detecting a roll gap value by a roll gap detector of WS / DS of a rolling mill and using an absolute value of the difference as a parameter of the meandering amount. ing.

Further, Japanese Patent Laid-Open No. 63-212008 discloses a method of detecting a rolling force of WS / DS of a rolling mill with a load cell and using the difference as a parameter of the meandering amount.

Further, as described in JP-A-3-60811, a method is proposed in which the tension of WS / DS of the material to be rolled is detected by a tension detector and the difference is taken as a parameter of the meandering amount. Has been done.

Further, Japanese Patent Laid-Open No. 4-55010 discloses a method in which the speed of WS / DS of a material to be rolled is detected by a speed detector and the difference is used as a parameter of the amount of meandering.

[0008]

[Problems to be Solved by the Invention]
Although various methods of detecting the amount of meandering have been taken to suppress the meandering of the plate material that occurs in pinch rolls, etc.,
For example, it is necessary to convey the material continuously for a long time, such as in a thin-walled continuous casting equipment, the material is extremely thin, and the material temperature is extremely high just below the freezing point, and the material temperature is conveyed. However, in cases where the strength of the material is low, and it is not desirable to lower the temperature of the material metallurgically, none of them have sufficient functions or effects. ing.

For example, there are a method using an optical sensor and a method using a side pressing roll as a method for detecting the off-center amount of the material mentioned in the section of the prior art, but in the method using an optical sensor, the material temperature is high, Further, in the case of a process in which the material temperature varies depending on the material to be conveyed, it is necessary to install two types of detectors for low temperature and high temperature, which complicates the control of the equipment. Further, when the material has temperature unevenness in the plate width direction or when the shape of the plate width end portion is not parallel to the material advancing direction, the amount of meandering cannot be detected. In the method using the side press roll, if the plate thickness of the material is extremely thin, the plate temperature is extremely high, and the strength of the material is low, when the material meanders, the edge of the material hits the press roll, and the plate edge is folded. However, it hinders the material transport after the rolling mill and the pinch rolls.

In the method of detecting the roll gap value of WS / DS and using the absolute value of the difference as a parameter of the meandering amount, the roll gap detection value is used as a mechanical component such as rolls and bearings forming a rolling mill and pinch rolls. Manufacturing accuracy error, rolling mill and pinch roll equipment installation accuracy error,
Since the difference between the right and left plate thicknesses on the inlet side, mill rigidity difference, and roll gap detector detection error deviates from the true roll gap value, even if the meandering control is performed using the difference in the absolute value of the roll gap detection value as the meandering amount parameter, the meandering It is difficult to converge.

A method of detecting the rolling load of WS / DS by a load cell and using the difference as a parameter of the meandering amount is as follows.
This is not applicable to rolling mills and pinch rolls that perform constant pressure reduction control, because the control that keeps the WS / DS reduction force constant is always performed.

Further, in the method of detecting the tension of the material of WS / DS and detecting the difference as a parameter of the meandering amount, when the plate temperature is high, the surface of the press roll for detecting the difference in tension is oxidized, The roll becomes unusable due to deterioration of the roll material or reduction in strength due to temperature rise. Further, if the inside of the roll is cooled, the temperature rise of the roll can be avoided, but the temperature of the material is also lowered.

Further, as a method of detecting the speed of the material of WS / DS by a speed detector and using the difference as a parameter of the meandering amount, there are a method using an optical sensor and a method using a measuring roll. There are limited applications due to the same reasons as problems for methods of detecting off-center of materials.

As described above, the method of detecting the amount of meandering using the optical sensor and the pressing roll is such that the plate thickness of the material is extremely thin and the plate temperature is extremely high just below the freezing point as in the thin wall continuous casting equipment, and the material is conveyed. The material temperature varies depending on the material to be used, and it is difficult to apply in a process in which the material needs to be continuously conveyed for a long time.

The problem to be solved in the present invention is to find a parameter suitable for detecting the amount of meandering of a material in a process under the above conditions, and to propose a control method for suppressing the meandering using the parameter. Is.

[0016]

The present invention is a method for detecting the amount of meandering and a meandering control method for a rolling mill and pinch rolls for performing constant pressure reduction control. As a method of detecting the amount of meandering, the amount of change over time in the roll gap value of WS / DS is taken as a parameter of the amount of meandering. 2. As a meandering control method, leveling control is performed on the rolling force of WS / DS so that the above-mentioned time variation amount becomes zero.

[0017]

[Operation] When the material is pressed down by the constant pressure rolling-down control, even if the meandering does not occur, machining error of the mechanical part, installation error,
The roll gap detection value shows a different value between WS and DS due to the difference in the thickness of the left and right plates on the inlet side, the difference in mill rigidity, the detection error of the roll gap detector, and the like. However, when the meandering does not occur, each roll gap detection value is constant regardless of time change.

When sideslip occurs in the roll axial direction due to some factor during rolling, the material center shifts from the roll center, so that the moment arm from the roll bearing to the material center position changes, and the material roll center is centered. Since the rolling force distribution varies depending on WS / DS, the rolling amount of the material varies depending on WS / DS of the rolled material. As a result, the roll gap detection value of the roll gap detector also changes. For example, when the material rolls sideways in the WS direction with respect to the roll center, the distribution of the rolling force of the material becomes larger on the DS side on the opposite side, and the rolling amount on the DS side increases. When the material is fed in that state, the skid of the material increases with the passage of time, and the time change amount of the roll gap detection value in the roll gap detector also increases.
Further, since the material is displaced from the roll center and the moment arm from the roll bearing to the center of the material is changed, a rotational moment in a direction perpendicular to the material advancing direction acts on the roll and the roll is tilted, which promotes side slip of the material. As the skid slips, the time variation of the roll gap detection value at the roll gap detector also increases. For example, when skidding in the WS direction, the moment arm on the DS side becomes large, so D
The rolls are inclined in the direction in which the S roll gap is tightened and in the direction in which the WS roll gap is opened, which promotes meandering in the WS direction.

Therefore, it is considered that the meandering amount is a function of the change amount of the roll gap detection value with time, and the change amount of the roll gap detection value with time is taken as a parameter of the meandering amount. The progress of the meandering is suppressed by performing the leveling control of the rolling force of WS / DS so that this value becomes 0.

The method for detecting the amount of meandering and the method for controlling the meandering include the temperature of the material, the material shape defect, the manufacturing error of the mechanical parts constituting the rolling mill / pinch roll, the installation error at the time of installing the rolling mill / pinch roll, and the detector detection. Not affected by error. Further, there is no need to attach any special device for detection, and a roll gap detector installed in a normal constant pressure rolling mill, pinch roll, etc. can be used, which is advantageous in terms of equipment cost.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a typical application example of the present invention, 4Hi.
It is a block diagram showing a section of a constant pressure rolling mill and an example of a control method. The material 1 is sandwiched between an upper work roll 2 and a lower work roll 3. The upper work roll 2 is supported by the upper backup roll 4, and the lower work roll 3 is supported by the lower backup roll 5. Each of the backup rolls is supported by a bearing box 7 via a bearing 6, the upper bearing box is in contact with an upper fixed frame 10, and the lower bearing box is a WS / DS press-up cylinder 8 installed on a lower fixed frame 11. I am touching 9.

The amount of movement of the WS / DS pressurizing cylinders 8 and 9 is treated as a roll gap change amount. WS / DS
The amount of movement of the pressurizing cylinders 8 and 9 is WS directly connected to the ram.
The amount of movement of the DS detection rods 12 and 13 is detected by the WS / DS roll gap detectors 14 and 15. WS / DS
The roll gap detection value δ detected by the roll gap detectors 14 and 15 is transmitted to the upper CPU 16.

The host CPU 16 sets a WS / DS rolling force instruction signal, and the WS / DS rolling force setting devices 17, 18 are set.
Then, the WS / DS pressure reducing force setting devices 17 and 18 receive the pressure reducing force instruction signals to generate the pressure reducing force P in the WS / DS pressure increasing cylinders 8 and 9. The roll gap detection values δ _WS and δ _DS detected by the WS / DS roll gap detectors 14 and 15 are changed in time by the upper CPU 16 Δδ / Δt.
To the leveling force Ft which is a function of the time variation Δδ / Δt.

Next, the WS before the meandering in the upper CPU 16
A leveling force Ft is applied to the DS rolling force P, and a corrected rolling force instruction signal to which the leveling force Ft is added is transmitted to the WS / DS rolling force setting devices 17 and 18. The WS / DS pressure reducing force setting devices 17 and 18 transmit the corrected pressure reducing force to which the leveling force Ft is applied by the correction pressure reducing force instruction signal to the WS / DS pressure increasing cylinders 8 and 9. The upper CPU 16 uses the time change amount Δδ / Δt of the roll gap detection value δ as a parameter of the meandering amount and outputs a rolling force correction signal so that the time change amount Δδ / Δt becomes zero.

Leveling force Ft and time variation Δδ / Δt
Is shown below. Leveling force Ft Ft = f (Δδ / Δt)

FIG. 2 is a block diagram showing another embodiment to which the meandering control method of the present invention is applied. In this example WS
The DS roll gap detection values δ _WS and δ _DS are converted into time variations Δδ _WS / Δt and Δδ _DS / Δt separately for WS and DS. Next, WS and DS are converted separately into leveling force that is a function of the time variation Δδ / Δt, and WS and DS before meandering are converted.
A leveling force is applied to the rolling force P, and a corrected rolling force instruction signal to which the leveling force Ft is added is transmitted to the WS / DS rolling force setting device. It is characterized in that the meandering control using the time change amount of the roll gap detection value as a parameter is performed separately for WS and DS.

Leveling force Ft and time variation Δδ / Δt
Is shown below. Leveling force Ft Ft _WS = f (Δδ _WS / Δt) Ft _DS = (Δδ _DS / Δ
t)

FIG. 3 is also a block diagram showing another embodiment to which the meandering control method of the present invention is applied. In this example WS
It is characterized in that the rolling force P of either one of the DSs is made constant and the leveling control is performed by one of the WS / DS. The control method is to convert the WS / DS roll gap detection values δ _WS / δ _DS detected by the roll gap detector into the time change amount Δδ / Δt, and then convert the leveling force as a function of the time change amount Δδ / Δt. Then, the leveling force is applied to the WS / DS rolling force P before the meandering, and the corrected rolling force instruction signal is transmitted to one of the rolling force setting devices of WS / DS. At this time, the pressing force P on the opposite side is constant.

Leveling force Ft and time variation Δδ / Δt
Is shown below. Leveling force Ft Ft = f (Δδ / Δt)

FIG. 4 shows the correlation between the side slip due to the meandering of the material between the work rolls and the inclination of the rolls.
State 1 in (a) represents a state before meandering, and state 2 in (b) represents a state in which the material is meandering in the WS direction. In the state 1, 2 is an upper work roll, 3 is a lower work roll,
The roll bearing of WS / DS receives a force from the vertical direction with a uniform pressure reduction force. The material is sandwiched between the upper and lower work rolls at the roll center. In state 2, the material starts to skid with the occurrence of meandering, and W
By shifting to the S side, the rolling force distribution centering on the roll center of the material becomes WS <DS, the rolling reduction amount of the material changes, and because the material position shifts from the roll center, Due to the inclination of the roll caused by the rotation moment acting on the roll, the WS side of the roll gap widens and the DS side tightens.

FIG. 5 is an example of a chart showing the time change of the WS / DS roll gap value when the WS is meandered when the rolling is performed by the constant pressure rolling-down control. Until the meandering occurs, the roll gap value of WS / DS is a constant value because the roll itself is not tilted although the absolute value is different. When the WS is meandered, the roll inclines in the WS roll gap opening direction and the DS side roll gap in the closing direction. The sideslip increases to WS with time and the roll inclination also increases, so the WS roll gap value increases and the DS roll gap value decreases.

[0032]

According to the present invention described above, it is possible to detect the amount of meandering without being affected by material temperature, material shape defect, detector accuracy, manufacturing defect of rolling mill / pinch roll, installation defect, and the like. In addition, the material must be transported continuously for a long time, the strength of the material is low at high temperature, and it is not desirable to lower the temperature of the material metallurgically. It can be applied to prevention control.

[Brief description of drawings]

FIG. 1 is an explanatory view of a meandering amount detection method of the present invention, and is a cross-sectional view of a 4Hi constant pressure rolling mill to which the present invention is applied.

FIG. 2 is a block diagram showing an embodiment to which the meandering control method of the present invention is applied.

FIG. 3 is a block diagram showing an embodiment to which the meandering control method of the present invention is applied.

FIG. 4 is a conceptual diagram showing occurrence of meandering, side slippage of material, and changes in roll gap in a rolling mill / pinch roll that performs constant pressure reduction control.

FIG. 5 is a chart showing changes over time in the WS / DS roll gap value when the material meanders in WS in a rolling mill / pinch roll that performs constant pressure reduction control.

[Explanation of symbols]

 1 Material 2 Upper Work Roll 3 Lower Work Roll 4 Upper Backup Roll 5 Lower Backup Roll 6 Bearing 7 Bearing Box 8 WS Pressure Cylinder Ram 9 DS Pressure Cylinder Ram 10 Upper Fixed Frame 11 Lower Fixed Frame 12 WS Detection Rod 13 DS Detection Rod 14 WS roll gap detector 15 DS roll gap detector 16 Upper CPU 17 WS pressure-up system pressure reduction setting device 18 DS pressure-pressure system pressure reduction setting device

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location 8315-4E B21B 37/00 119 Z

Claims (2)

[Claims] 1. In the meandering control of a material in a rolling mill and a pinch roll for performing constant pressure reduction control, a work side
A method for detecting the amount of meandering, wherein the amount of change over time in the roll gap detection value on the drive side is taken as a parameter for the amount of meandering. 2. The meandering is corrected by correcting the work side / drive side rolling force of the rolling down device so that the time change amount of the roll gap detection value, which is a parameter in claim 1, becomes zero. Control method for suppressing meandering.