JP4772934B1 - Metal plate rolling machine and rolling method - Google Patents

Abstract

This invention makes it a subject to provide the rolling mill which can provide the high response and strong roll bending force while being able to take the opening degree between upper and lower work rolls large.
In order to solve the problems, the rolling mill provided by the present invention is a metal plate rolling mill having a pair of upper and lower work rolls and a pair of upper and lower reinforcing rolls that respectively support the work rolls. A hydraulic cylinder that loads the leasing bending force is arranged in the project block protruding inward of the rolling mill housing, and the rolling direction force applied to the lower work roll body is determined by the contact surface between the project block and the lower work roll chock. Rolling of a metal plate material, characterized in that the rolling direction force supported and applied to the upper work roll body is supported by the contact surface between the rolling mill housing window and the upper work roll chock located above the project block. Machine.
[Selection] Figure 1

Description

The present invention relates to a rolling mill for metal sheets, and relates to a rolling mill having high responsiveness and capable of imparting a strong roll bending force. In particular, the present invention relates to a rolling mill that is suitable for a thick plate rolling mill or a thin sheet hot rolling rough rolling mill and that can provide a large maximum opening between upper and lower work rolls and can impart a strong roll bending force.
Furthermore, the present invention also relates to a rolling method using the above rolling mill, which can provide a high response and a strong plate crown / shape control function.

In the rolling operation of a metal plate material, the crown and shape of the rolled plate are important quality indicators, and many techniques related to plate crown and shape control have been disclosed.
However, for example, in a rolling mill that manufactures a thick product by multi-pass reverse rolling, such as a thick plate rolling mill or a thin plate hot rolling rough rolling mill, the gap between the upper and lower work rolls (roll opening) It must be larger than the thickness of the rolled material. For this reason, restrictions on the rolling mill equipment design are imposed on the plate crown / shape control device.

For example, in Patent Document 1, in thick plate rolling in which a plurality of passes are rolled to a predetermined plate thickness, a work roll bending device is used as a shape control device, and the roll bending force is controlled based on the result of rolling in the previous pass. A rolling method is disclosed.
The rolling mill type disclosed in Patent Document 1 is a four-high rolling mill, and the rolling mill type has a structure shown in FIG. The rolling mill shown in FIG. 10 is obtained by arranging a decrease bending apparatus in the rolling mill of FIG. Both rolling mills have basically the same structure. In other words, the upper work roll chock 3-1 is held by the arm portion that connects the upper reinforcement roll chock 4-1. Increase bending apparatuses 6-1 and 6-2 of the upper work roll 1-1 are incorporated in this arm portion. By setting it as such a format, a big roll opening degree can be taken.

  In the rolling mills of FIGS. 10 and 14, the increment bending apparatuses 6-3 and 6-4 of the lower work roll 1-2 are incorporated in a project block connected to the rolling mill housing 9. In addition to this, as a rolling mill type capable of taking a large roll opening degree, as shown in FIG. 11, the rolling roll chocks 4-1 and 4-2 hold the work roll chock 3-1 and 3-2 on both the upper and lower sides. There is also a machine.

The increment bending apparatus means a hydraulic apparatus that applies a force in the direction of increasing the roll opening degree to the work roll chock. The increment bending apparatus is a general term for apparatuses including a hydraulic cylinder as an actuator. However, in the present invention, in order to simplify the description, the increment bending apparatus refers to a hydraulic cylinder that is an actuator thereof unless otherwise specified. A force applied to the work roll by the increase bending apparatus is referred to as an increase bending force.
On the other hand, a hydraulic device that applies a force in the direction of decreasing the roll opening degree to the work roll chock is referred to as a decrease bending device, and a force applied to the work roll by this is referred to as a decrease bending force. The decrease bending apparatus is a general term for apparatuses including a hydraulic cylinder as an actuator. However, in the present invention, in order to simplify the description, the decrease bending apparatus refers to a hydraulic cylinder that is an actuator thereof unless otherwise specified.

  Patent Document 2 discloses a rolling mill in which work roll increase bending apparatuses 6-1 and 6-2 are incorporated in work roll chocks 3-1 and 3-2 as shown in FIG.

  Patent Document 3 discloses a roll cloth type rolling mill. Also in this rolling mill, as shown in FIG. 12, the increment bending apparatuses 6-1 and 6-2 are incorporated in the work roll chock 3-1 and 3-2.

Patent Document 4 discloses a rolling mill having a work roll shift function as shown in FIG. In this rolling mill, the increment bending apparatuses 6-1 and 6-2 are incorporated in project blocks 5-1 and 5-2 integrated with the rolling mill housing. In the rolling mill disclosed in Patent Document 4, a plurality of hydraulic cylinders of the increment bending apparatus are arranged in the roll axis direction, and are devised so that an uneven load is not applied when the work roll is shifted.
In general, a thick steel plate rolling machine does not have a decrease bending apparatus as shown in FIG. (See Patent Documents 1, 2, 3, and 4)
However, the rolling mill according to the present invention is premised on having a decrease bending apparatus in order to provide a powerful plate crown / shape control function. Therefore, FIG. 10, FIG. 11, FIG. 12, and FIG. 13 show cases where a decrease bending apparatus is provided.

JP-A-6-87011 JP-A-62-220205 JP-A-6-198307 Japanese Patent Laid-Open No. 4-52014

  A typical thick plate rolling mill as disclosed in Patent Document 1 (the rolling mill shown in FIGS. 10 and 11) is designed with the highest priority given to a large roll opening. That is, the arm portion connected to the upper reinforcing roll chock 4-1 whose vertical position is set and controlled by the reduction device 11 is configured to hold the upper work roll chock 3-1. In addition, since the increment bending apparatuses 6-1 and 6-2 are incorporated into the arm portion, which is structurally limited in size, it is difficult to incorporate a large capacity hydraulic cylinder. For this reason, a strong roll bending force cannot be imparted.

  For example, even in a hot strip mill finishing rolling mill having a work roll diameter of about 800 mm, a work roll bending apparatus having a capacity exceeding 200 tf / chock has been put into practical use. On the other hand, only a work roll bending apparatus having a work roll diameter of about 200 tf / check has been put to practical use even in a thick plate mill having a work roll diameter of about 1000 mm. From the contrast of the roll diameter, it is clear that a higher capacity roll bending force is required.

  Here, the roll deflection, which is an index of the roll bending effect, is inversely proportional to the roll secondary moment when the applied bending moment is the same. Therefore, the roll bending effect of the thick plate mill with a work roll diameter of 1000 mm is inferior by about 60% compared to the hot strip mill finish rolling mill with a work roll diameter of 800 mm.

For this reason, a roll cross function and a roll shift function have been put into practical use and mainly used as a plate crown / shape control device of a thick plate rolling mill. Work roll bending devices are rarely used.
However, it is difficult to quickly change the settings of the roll cloth function and the roll shift function during rolling. Therefore, since it is impossible to remove the disturbance factor during rolling, it must be said that the shape control end is incomplete.

On the other hand, when the increment bending apparatuses 6-1 and 6-2 are incorporated in the work roll chock 3-1 and 3-2 as in the rolling mill disclosed in Patent Documents 2 and 3 (FIG. 12). The hydraulic cylinder stroke can be taken longer. Thereby, a large roll opening degree can be realized. In addition, since it is possible to incorporate a large capacity hydraulic cylinder, a practical work roll bending effect can be expected even with a thick plate mill.
On the other hand, the work rolls 1-1 and 1-2 are more easily worn out than the reinforcing rolls due to rolling operation, and therefore it is necessary to periodically change the rolls. For this reason, it is necessary to attach and detach the hydraulic piping of the increment bending apparatus every time the reassembly work is performed. This not only lengthens the roll reassembly time, but also increases the possibility of minute foreign matter entering the hydraulic piping when the piping is attached or detached.
For this reason, this rolling mill cannot employ a servo valve for high response hydraulic control. In addition, in order to facilitate the attachment / detachment of the pipe, it must be connected to each hydraulic control valve via a flexible and detachable hydraulic pipe (flexible pipe or the like). In addition, when flexible piping is employed, fluctuations in hydraulic pressure may be absorbed and relaxed due to the flexible structure. Therefore, it becomes difficult to obtain a roll bending apparatus with high responsiveness.

On the other hand, the rolling mills disclosed in Patent Documents 2 and 4 (FIG. 13) are incorporated in project blocks 5-1 and 5-2 in which the increment bending apparatuses 6-1 and 6-2 are connected to the rolling mill housing 9. Yes. For this reason, it is not necessary to attach or detach the hydraulic piping of the increment bending apparatus every time the roll is reassembled. Therefore, this rolling mill can be a roll responsive apparatus with high responsiveness. Therefore, it is frequently used in hot strip mill finish rolling mills.
However, in this rolling mill, it is the contact surface between the work roll chock 3-1 and the project block 5-2 that supports the rolling direction force such as offset component force acting on the upper work roll 1-1. Therefore, when the roll opening degree is increased by operating the reduction device 11, the rotation center of the work roll becomes outside the contact surface, and the posture of the work roll chock 3-1 becomes unstable. As a result, a large roll opening cannot be taken. For this reason, this rolling mill is rarely adopted in a thick plate rolling mill that requires a large roll opening.

  As described above, in the rolling mill capable of increasing the roll opening degree, there is no rolling mill capable of incorporating a powerful work roll bending apparatus with high response. The problem to be solved by the present invention is to provide a rolling mill which can take a large opening between the upper and lower work rolls and can provide a high response and a strong roll bending force.

In order to solve the above-mentioned problems, the present inventors have intensively studied, and as a result, shifted the project block protruding inward from the housing to the lower side with respect to the pass line, and moved up and down with respect to the pass line. It has been found that the installation can be made asymmetrical to enable the following.
(A) A structure in which the rolling direction force applied to the upper work roll chock is always received by the housing. Thereby, it is possible to stably support the work roll chock regardless of the roll opening degree.
(B) An upper and lower increase bending apparatus can be incorporated in the project block. Thereby, it is possible to provide a powerful bending device with a large capacity and a large stroke.
(C) In addition, the hydraulic piping can be fixed and the servo valve can be applied by incorporating the increment bending device into the project block. This makes it possible to control the incremental bending force with high response.
Moreover, it discovered that the invention on these apparatuses enabled the following rolling mill operating methods.
(D) Even in the case of a decrease bending device with low responsiveness, it is possible to control the bending force with high response by cooperating with the incremental bending device with high responsiveness. This greatly improves product quality and rolling yield.
The present invention has been made based on these findings, and the gist thereof is as follows.

(1) A metal sheet material rolling mill having a pair of upper and lower work rolls and a pair of upper and lower reinforcing rolls that respectively support the work rolls, and a hydraulic cylinder that applies an incremental bending force to the upper and lower work rolls, respectively, Rolling direction force is applied to the lower work roll body, which is provided on the project block projecting inward, and is applied to the upper work roll body by the contact surface between the project block and the lower work roll chock. The metal plate rolling machine, wherein the force is supported by a contact surface between a rolling mill housing window and an upper work roll chock located above the project block.
As described above, the increment bending apparatus is a general term for apparatuses including a hydraulic cylinder as an actuator. However, in the present invention, in order to simplify the description, the increment bending apparatus refers to a hydraulic cylinder that is an actuator thereof unless otherwise specified.

  (2) The hydraulic cylinder that applies the increase bending force to the upper work roll and the hydraulic cylinder that applies the increase bending force to the lower work roll are arranged at different positions on the plan view in the project block. (1) The metal plate rolling machine according to (1).

(3) The metal plate rolling mill according to (1) or (2), wherein a hydraulic cylinder that applies a decrease bending force to the upper work roll is provided in the upper reinforcing roll chock.
Similar to the increment bending apparatus, in the present invention, the decrease bending apparatus is a general term for an apparatus including a hydraulic cylinder which is an actuator thereof. However, in the present invention, in order to simplify the description, the decrease bending apparatus refers to a hydraulic cylinder that is an actuator thereof unless otherwise specified.
(4) A hydraulic cylinder that applies a decrease bending force to the lower work roll is attached to the lower reinforcement roll chock or the second project block (for example, 5-3 and 5-4 in FIG. 4) located below the project block. The metal sheet rolling machine according to any one of (1) to (3), wherein the rolling mill is provided.

(5) A method for rolling a metal sheet material using the metal sheet material rolling mill described in (3) above,
Before starting rolling, both the increase bending force and the decrease bending force are applied, and a roll bending force corresponding to the roll balance force is applied to the work roll chock as a resultant force.
After that, while changing the decrease bending force to become the decrease bending force during the predetermined rolling, the increase bending force is maintained so that the combined force of the decrease bending force and the increase bending force maintains the roll balance force. Change. In this step, the increase bending force is applied to the work roll chock so that the decrease bending force is initially set as the decrease bending force during rolling, and the resultant balance of the decrease bending force and the increase bending force becomes the roll balance force. If you let it, you can omit it.
After that, at the start of rolling, the increase bending force is changed to the work roll chock as a resultant force while changing the increase bending force while continuing the control of maintaining the decrease bending force during the predetermined rolling. Make it work.
During rolling, performing the rolling so as to maintain the work roll bending force during the predetermined rolling,
Thereafter, at the end of rolling, the increment bending force is changed, and the roll bending force corresponding to the roll balance force is applied to the work roll chock as a resultant force with the decrease bending force, and the rolling of the metal plate material is finished in this state.
Thereafter, the decrease bending force and the increase bending force are decreased so as to maintain the roll balance force as the resultant force. This step also maintains the decrease bending force during the specified rolling, and the increase bending force is set so that the resultant balance of the decrease bending force and the increase bending force becomes the roll balance force. Can be omitted if it works.
It is the rolling method of the metal plate material characterized by the above.

  (6) Measure the hydraulic pressure in the hydraulic cylinder that generates the decrease bending force or in the hydraulic piping connected to the hydraulic cylinder, and based on the measured value, the roll bending force acting on the work roll chock becomes a predetermined value based on the measured value. The rolling method of the metal sheet according to (5), wherein the increment bending force is controlled as described above.

As shown in FIG. 1, the rolling mill according to the present invention applies a rolling direction force applied to the body portion of the upper work roll 1-1 to a housing window above the upper work roll chock 3-1 and the project block 5-2. Is supported by the contact surface. Therefore, a large roll opening degree can be obtained and a strong roll bending force can be obtained.
And it is not necessary to attach or detach the hydraulic piping of the increment bending apparatus every time the work roll is reassembled. For this purpose, it is possible to connect to each hydraulic control valve via fixed hydraulic piping to the incremental bending device, and it is possible to adopt a servo valve for high response hydraulic control, highly responsive incremental bending It can be a device.

The rolling method according to the present invention compensates for this by a highly responsive incremental bending apparatus even when a declining bending apparatus having low responsiveness must be provided. A crown / shape control function can be added.
Therefore, it is possible to build a good plate crown and shape against disturbances that change during rolling, such as the rolled material entry side thickness and the rolled material temperature, which can greatly improve product quality and yield. .

It is a side view which shows an example of the structure of the rolling mill which concerns on this invention. It is a perspective top view which shows the example of arrangement | positioning of an upper and lower increase bending apparatus. It is a perspective top view which shows the example of arrangement | positioning of an upper and lower increase bending apparatus. It is a side view which shows another example of the structure of the rolling mill which concerns on this invention. It is a figure which shows an example of the operation flow of the rolling method which concerns on this invention. It is a figure which shows time-sequential changes, such as roll bending force accompanying the operation flow of FIG. It is a figure which shows time-sequential changes, such as roll bending force, when the responsiveness of a decrease bending apparatus is low. It is a figure which shows another example of the operation flow of the rolling method which concerns on this invention. It is a figure which shows time-sequential changes, such as roll bending force accompanying the operation flow of FIG. It is a side view which shows the structure of the rolling mill which concerns on a prior art. It is a side view which shows the structure of the rolling mill which concerns on a prior art. It is a side view which shows the structure of the rolling mill which concerns on a prior art. It is a side view which shows the structure of the rolling mill which concerns on a prior art. It is a side view which shows the structure of the rolling mill which concerns on a prior art.

Hereinafter, with reference to FIGS. 1-13, the rolling mill which concerns on this invention, and the rolling method using this rolling mill are demonstrated.
FIG. 1 is a side view showing an example of the structure of a rolling mill according to the present invention. As shown in the figure, a rolling mill according to the present invention includes a pair of upper and lower work rolls 1-1 and 1-2 and a pair of upper and lower reinforcing rolls 2-1 and 2-2 for supporting them. It is.
The rolling mill according to the present invention provides the upper bending machine 6-1 and 6-2 that applies the increase bending force to the upper work roll 1-1, and the increase bending force to the lower work roll 1-2. This is a rolling mill in which lower incremental bending apparatuses 6-3 and 6-4 to be loaded are arranged in project blocks 5-1 and 5-2 protruding inside the housing 9.

  This is the same as the conventional rolling mill shown in FIG. However, the rolling mill according to the present invention performs a fundamental review and solves the problems of the conventional rolling mill shown in FIG. That is, the position of the project blocks 5-1 and 5-2 and the shape of the upper work roll chock 3-1 were changed from the viewpoint of structural design of the rolling mill, particularly from the viewpoint of increasing the roll opening.

The conventional rolling mill shown in FIG. 13 cannot take a large roll opening. In this rolling mill, the project blocks 5-1 and 5-2 are arranged so as to be almost vertically symmetrical with respect to a position (pass line) through which the material to be rolled 10 passes. For this reason, the rolling direction force such as offset component force acting on the upper work roll 1-1 by the contact surface where the upper work roll chock 3-1 and the project block 5-2 are in contact, that is, the material to be rolled 10 and the upper reinforcement This is because the structure supports the rolling direction force applied to the body of the upper work roll 1-1 from the roll 2-1 or the like.
In this structure, as the roll opening degree is increased, the rotation center position (the point of action of the rolling direction force) of the upper work roll 1-1 and the upper work roll chock 3-1 move upward to support the rolling direction force. The contact area with the project block 5-2 is reduced. Therefore, the posture of the upper work roll chock 3-1 becomes unstable as the roll opening degree is increased, and a large roll opening degree cannot be taken.

  The rolling mill according to the present invention solves the above problems. As shown in FIG. 1, the rolling mill according to the present invention arranges project blocks 5-1 and 5-2 projecting inward from the housing 9 at positions shifted downward with respect to the pass line. That is, unlike the conventional rolling mill shown in FIG. 13, the project blocks 5-1 and 5-2 are arranged so as to be vertically asymmetric with respect to the pass line. Further, the upper work roll chock 3-1 does not contact the project block 5-2 and support the rolling force, but contacts the housing window to support the rolling force.

Thereby, in the rolling mill which concerns on this invention, rolling of offset component force etc. which act on the upper work roll 1-1 with the contact surface of the upper work roll chock 3-1 and the housing window 12 above the project block 5-2 is carried out. The directional force, that is, the rolling direction force applied to the body portion of the upper work roll 1-1 from the material to be rolled 10, the upper reinforcing roll 2-1 or the like is supported.
With such a structure, even if the roll opening degree is increased by operating the rolling device 11 of the rolling mill, the area where the upper work roll chock 3-1 and the housing window are in contact does not change at all. Therefore, the posture of the upper work roll chock 3-1 is always stably maintained regardless of the roll opening degree.

As shown in FIG. 13, a rolling mill in which upper and lower increase bending apparatuses are arranged in a project block is well known. However, the rolling mill according to the present invention performs a fundamental review of the positions of the project blocks 5-1 and 5-2 and the shape of the upper work roll chock 3-1, Since the applied rolling direction force is supported by the contact surface between the upper work roll chock 3-1 and the housing window 12 above the project block 5-2, a large roll opening can be obtained.
Furthermore, in the rolling mill according to the present invention, the upper bending apparatus 6-1 and 6-2 for applying the increase bending force to the upper work roll 1-1, and the increase bending force to the lower work roll 1-2. The lower increase bending apparatuses 6-3 and 6-4 to be loaded are arranged in the project blocks 5-1 and 5-2 protruding inside the housing 9. Therefore, it is not necessary to attach or detach the hydraulic piping of the increment bending apparatus every time the work rolls are reassembled, and an increase bending responsive apparatus can be obtained. This is because each hydraulic control valve can be connected via a fixed hydraulic pipe, and a servo valve for high response hydraulic control can be employed.

In the rolling mill according to the present invention, the rolling direction force applied to the body portion of the lower work roll 1-2 is supported by the contact surface between the lower work roll chock 3-2 and the project block 5-2. For this reason, the rolling mill according to the present invention shown in FIG. 1 increases the height of the portion sandwiched between the project blocks 5-1 and 5-2 of the lower work roll chock 3-2.
Moreover, since the roll opening is adjusted mainly by moving the upper work roll chock up and down, the amount of movement of the lower work roll chock up and down is small. Therefore, the posture of the lower work roll does not become unstable as the roll opening degree increases.

FIG. 2 is a sectional plan view showing an arrangement example of the upper and lower increase bending apparatuses. That is, it is a cross-sectional view of the pass line height of the project blocks 5-1 and 5-2.
In the rolling mill according to the present invention, it is desirable that the upper and lower increase bending apparatuses are shifted from each other on the sectional plan view of the project block. For example, as shown in FIG. 2, the upper increment bending devices 6-1 and 6-2 and the lower increment bending devices 6-3 and 6-4 are shifted in the axial direction of the work roll 1-2. It is desirable to deploy in a relationship. In this way, the upper and lower increase bending apparatuses do not interfere with each other. It is possible to increase the stroke of the upper increment bending devices 6-1 and 6-2, and to take a larger roll opening.
In FIG. 2, each of the lower increase bending apparatuses 6-3 and 6-4 has two hydraulic cylinders on the input side and the output side. However, the same effect can be obtained by arranging one hydraulic cylinder at different positions in the axial direction of the work roll 1-2 so as not to interfere with the upper increment bending apparatuses 6-1 and 6-2.

  FIG. 3 is also a cross-sectional plan view showing an arrangement example of the upper and lower increase bending apparatuses. That is, it is a sectional view of the pass line height of the project blocks 5-1 and 5-2. As shown in the figure, the upper increment bending apparatuses 6-1 and 6-2 and the lower increase bending apparatuses 6-3 and 6-4 may be in a positional relationship shifted in the rolling direction. Even in such an arrangement, the upper and lower increase bending apparatuses do not interfere with each other. It is possible to increase the stroke of the upper increment bending devices 6-1 and 6-2, and to take a larger roll opening.

  Up to this point, the structure of the rolling mill according to the present invention has been described mainly from the viewpoint of obtaining a large roll opening, which is one of the problems to be solved. Next, it will be described that according to this structure, the application of a strong roll bending force, which is another problem to be solved, can be easily achieved.

10 and 11 are both rolling mills according to the prior art, and any rolling mill can take a large roll opening.
However, these conventional rolling mills cannot provide a strong roll bending force. This is a structure in which the upper increase bending devices 6-1 and 6-2 are incorporated in the arm portion that protrudes downward from the upper reinforcing roll chock 4-1, so that the upper increase bending device 6- has a large capacity and a large stroke. This is because 1, 6-2 cannot be deployed. Moreover, since these rolling mills take out an arm part from an upper reinforcement roll chock, the installation space of an upper decrease bending apparatus will approach the axial center of a roll. Therefore, since it interferes with the bearing of the upper reinforcing roll, the large capacity upper decrease bending devices 7-1 and 7-2 cannot be provided.

On the other hand, as shown in FIG. 1, in the rolling mill according to the present invention, a large-capacity / large-stroke upper increment bending apparatus is provided in the project blocks 5-1 and 5-2 projecting inward from the housing 9 of the rolling mill. 6-1, 6-2 can be deployed.
Further, in the rolling mill according to the present invention, the upper reinforcing roll chock 4-1 does not include an arm portion like the rolling mill shown in FIGS. For this reason, the large capacity upper decrease bending apparatuses 7-1 and 7-2 can be provided at positions that do not interfere with the bearings of the upper reinforcing roll of the upper reinforcing roll chock 4-1. As a result, it is possible to apply a large decrease bending force to the upper work roll 1-1.

That is, a fundamental review of the positions of the project blocks 5-1 and 5-2 and the shape of the upper work roll chock 3-1 is performed, and the rolling direction force applied to the trunk of the upper work roll 1-1 is According to the rolling mill according to the present invention that is supported by the contact surface between the upper work roll chock 3-1 and the housing window 12, a large roll opening degree can be obtained and a strong roll bending force can be applied. .
Further, it is not necessary to attach or detach the hydraulic piping of the increment bending apparatus every time the work roll is reassembled. For this reason, each increment bending apparatus 6-1 to 6-4 can be connected to each hydraulic control valve via a fixed hydraulic pipe, and employs a servo valve for high response hydraulic control. be able to. Therefore, it is possible to provide an incremental bending apparatus with high responsiveness.

  FIG. 4 is a side view showing another example of a rolling mill according to the present invention. In the rolling mill shown in FIG. 4, the upper roll system has the same configuration as that of FIG. 1, but the lower roll system has a different configuration. In the rolling mill shown in FIG. 1, lower decrease bending apparatuses 7-3 and 7-4 that apply a decrease bending force to the lower work roll are provided in the lower reinforcing roll chock 4-2. On the other hand, in the rolling mill shown in FIG. 4, the lower decrease bending apparatuses 7-3 and 7-4 are arranged in dedicated project blocks 5-3 and 5-4 located below the project blocks 5-1 and 5-2. Has been deployed.

By the way, when the lower decrease bending apparatuses 7-3 and 7-4 are arranged in the lower reinforcing roll chock 4-2 as in the rolling mill shown in FIG. 1, when the lower reinforcing roll 2-2 is reassembled, the decrease bending apparatus Hydraulic piping must be attached and detached. In other words, there is a high possibility that minute foreign matter will be mixed in the hydraulic piping during attachment / detachment.
For this reason, it is generally difficult to employ a servo valve for high response hydraulic pressure control, and flexible piping may have to be partially employed.
Therefore, the responsiveness of the roll bending apparatus is inevitably lowered as compared with the case where fixed piping and servo valves are employed.

  On the other hand, according to the rolling mill shown in FIG. 4, the said problem which arises when the lower reinforcement roll 2-2 is rearranged can be solved. This is because a servo valve for high-response hydraulic control can be used for the hydraulic piping of the lower decrease bending device deployed in the dedicated project block, and it is not necessary to use flexible piping. For this reason, it is possible to easily change the lower reinforcing roll 2-2 and to provide a roll responsive apparatus with high responsiveness.

Next, the rolling method according to the present invention will be described. As shown in FIGS. 1 and 4, when the upper decrease bending devices 7-1 and 7-2 are arranged in the upper reinforcement roll chock 4-1, when the upper reinforcement roll 2-1 is reassembled, the hydraulic pressure of the decrease bending device is changed. The pipe must be attached and detached, and there is a high possibility that minute foreign matter will be mixed in the hydraulic pipe when attaching and detaching.
For this reason, it is generally difficult to employ a servo valve for high response hydraulic control. In addition, in order to facilitate the attachment / detachment of the pipe, it is necessary to connect to each hydraulic control valve via a flexible and detachable hydraulic pipe such as a flexible pipe. In the case of adopting a flexible and detachable hydraulic pipe such as a flexible pipe, the fluctuation of the hydraulic pressure may be absorbed or alleviated because of the flexible structure.
Therefore, when the upper decrease bending devices 7-1 and 7-2 are provided in the upper reinforcing roll chock 4-1, the response of the roll bending device is less than when the fixed piping and the servo valve are used. It must be lowered.

By the way, the decrease bending force cannot be applied during idling when no rolling load is applied. Therefore, when applying the decrease bending force, it is necessary to quickly set the decrease bending force from the idle state in which the roll balance is achieved to the start of rolling, and to quickly return to the roll balance state at the end of rolling.
Therefore, when the roll bending force is changed by the control of the decrease bending device having poor responsiveness, there is a possibility that the predetermined defect bending force is not applied to the leading end of the rolled material and the defective shape portion becomes long. .

  The rolling method according to the present invention solves the above problems. That is, it is a rolling method using the rolling mill according to the present invention in which the upper decrease bending apparatuses 7-1 and 7-2 are arranged in the upper reinforcing roll chock 4-1, and solves the above-described problems that may occur in the rolling mill. It is a rolling method.

As described above, in the rolling mill in which the upper decrease bending apparatuses 7-1 and 7-2 are arranged in the upper reinforcing roll chock 4-1, the response of the decrease bending apparatus may be deteriorated.
However, in the rolling mill according to the present invention, the upper increment bending apparatuses 6-1 and 6-2 are arranged in the project blocks 5-1 and 5-2 protruding in the inner direction from the housing 9, Large increase and large stroke upper increment bending apparatuses 6-1 and 6-2 can be used.
In addition, since it is not necessary to attach and detach the hydraulic piping of the increment bending apparatus every time the rolls are changed, it is possible to employ a fixed hydraulic piping or a servo valve, which makes it possible to obtain an increase bending responsive apparatus. .
In the rolling method according to the present invention, when a decrease bending force is applied to a work roll for the purpose of plate crown and shape control, a change in roll bending force at the start of rolling and at the end of rolling is performed with a highly responsive increase. This is performed by using a bending apparatus and compensates for the response of the decrease bending apparatus.

FIG. 5 is a diagram showing an example of an operation flow of the rolling method according to the present invention. That is, it is a diagram showing an operation flow of an increase bending apparatus having a high response and a decrease bending apparatus having a slightly lower response than the above.
FIG. 6 shows time-series changes such as roll bending force for one rolled material in this rolling method. FIG. 6 shows the rolling load, the output of the increment bending apparatus, the output of the decrease bending apparatus, and the time series change of the work roll bending force, which is the resultant force, from the top. Hereinafter, a description will be given with reference to FIGS.
First start rolling before, then rolled settings F _R of the rolling work roll bending force corresponding to operation and output to the rolling. Here F _R is a negative value, that is, those which are calculated as decrease-bending force. In the present invention, the increase bending force (the force in the increase direction (the direction in which the roll is opened)) is a positive value, and the decrease bending force (the force in the decrease direction (the direction in which the upper and lower work rolls are pressed)) is negative. Value.

Prior to the start of rolling, both the increase bending force and the decrease bending force are applied, and the roll bending force on the increase side corresponding to the roll balance force (F _B ) is applied to the work roll chock as a resultant force.
That is, at idle before rolling, the increment bending device output is I _B (> 0), the decrease bending device output is D _B (<0), and I _B + D _B is the roll balance force F _B (> 0). Works.
Roll balancing force F _B is rolls as a work roll and a driven which are driven by an electric motor in the idling state is determined as a force that does not slip. This time D _B may be set at a level of minimum hydraulic actuator decrease-bending device is not Shimawa away from the work roll chock.

And in certain timing before the start of rolling (a point on the time axis), a sufficient predetermined rolling in decrease-bending device output D _S to exert the work roll bending force F _R during rolling D _{S =} F _R - computing the I _R. As the roll balancing force _{(F B)} is constant, at the same time outputs the _{D S} and _{I S.} Here, I _R is-bending device output during rolling, determined in advance a value close to minimum controllable value such that the absolute value of D _S does not become excessive. I _S is the output of the increment bending apparatus where I _S + D _S = F _B. Therefore, in the setting timing, the work roll bending force of the resultant force is substantially unchanged remains F _B.

Then, at the start of rolling, while decrease-bending force holds a constant value, reduce the increase-bending force, the work in a given rolling roll bending force F _R is to act on the work roll chock as resultant force.
Namely, at the time of start of rolling (b point on the time axis), it is changed to I _R ink bending device output from the I _S. While such decrease-lease low response by the bending device output D _S, the control of the quick-bending apparatus responsive, the work roll bending force of the resultant force from the roll balancing force F _{B (>} 0) It is possible to quickly switch to the work roll bending force F _R (<0) during rolling.
In addition, the rolling start time (b) refers to the time point when the rolling is started, and the detection thereof, for example, the load detected by the load cell for measuring the rolling load of the rolling mill exceeds 30% of the predicted rolling load. You can decide by the method of time.

Then, at the end of rolling, in order to return the roll bending force to the state before the start of rolling, a roll bending force corresponding to the roll balance force (F _B ) is applied to the work roll chock as a resultant force, and the rolling is ended.
That is, when completion of rolling (c point on the time axis), decrease-bending device output varies the fast-bending device output response from the I _R in I _S remain D _S. By doing in this way, the work roll bending force as a resultant force can be quickly switched from the work roll bending force during rolling (F _R (<0)) to the roll balance force (F _B (> 0)).
Note that the end of rolling (c) refers to the end of rolling. For example, the load detected by the load cell for measuring the rolling load of the rolling mill is less than 50% of the actual rolling load average value. What is necessary is just to decide by the method of timing.

Then from the time the end of rolling (c), for example, a time has elapsed 1-3 seconds and work completion timing (d points on the time axis), at this timing, the increase-bending device output I _B, decrease-bending device to change the output to the _{D B.} Even with this change, the work roll bending force as the resultant force is substantially maintained at the roll balance force (F _B ).

As shown in FIGS. 5 and 6, in the rolling method according to the present invention, the roll bending force is changed at the start of rolling and at the end of rolling by using an increase bending responsive apparatus. For this reason, even if it is necessary to deploy a decrease bending device having a relatively low response, a highly responsive increase bending device compensates for this. A shape control function can be provided.
Furthermore, even when the rolling load changes due to various factors (disturbances) during rolling, it is possible to quickly control to maintain the optimal work roll bending force with a highly responsive incremental bending device. It is. In this case, the control for changing the work roll bending force during rolling may be performed according to, for example, the measured value of the rolling load.
That is, according to the rolling method of the present invention, it is possible to build a good plate crown and shape against disturbances that vary during rolling, such as the rolled material entry side plate thickness and the rolled material temperature. Thereby, product quality and yield can be greatly improved.

  FIG. 7 is a diagram showing time-series changes in roll bending force and the like when the response of the decrease bending apparatus is low (particularly, when the reaction force is reduced and the pressure drops when the reaction force is released). Similar to FIG. 6, changes in time series such as a roll bending force accompanying a rolling operation on a single rolled material are shown in accordance with the operation flow of the increment bending apparatus and the decrease bending apparatus shown in FIG. 5. That is, an example in which the response speed of the decrease bending apparatus is slower than in the case of FIGS.

In the case of FIG. 7, the output of the increase bending apparatus with high responsiveness changes rapidly at timings b and c, and the output of the decrease bending apparatus with poor responsiveness fluctuates. As a result, the work roll bending force of the resultant force, is delayed to reach F _R at timing b, it will be delayed possible to reach F _B at the timing c. The rolling method shown in FIG. 8 solves this problem.

FIG. 8 is a diagram showing an operation flow in the case of having an increase bending device with high responsiveness and a decrease bending device with low responsiveness. Hereinafter, a description will be given based on the drawing.
In the rolling method shown in FIG. 8, the decrease bending force or the hydraulic pressure in the hydraulic piping connected to the apparatus is constantly measured by a load cell installed in the decrease bending apparatus, and the incremental bending apparatus is controlled based on the measured value. To do. That is, as work roll bending force before and after rolling is rolled balancing force F _B, during rolling as the work roll bending force is F _R, the output of the increase-bending device, decrease-bending force or decrease-lease Control according to the hydraulic pressure of the bending equipment. The other control is the same as the rolling method shown in FIG.
By rolling with the rolling method shown in FIG. 8, as shown in FIG. 9, the increase bending device compensates for fluctuations in the output of the decrease bending device, and the work roll bending force is optimized to achieve high-response control. Can be realized.
In addition, it is possible to predict the fluctuation of the output of the decrease bending apparatus in advance and set the output of the increment bending apparatus to compensate for it without the need for measuring the bending bending force during rolling or feedback control by measuring the hydraulic pressure. In this way, the same effect can be obtained.

  The present invention can be used for rolling a steel sheet, particularly a reverse rolling mill that requires a large opening.

1-1 Upper Work Roll 1-2 Lower Work Roll 2-1 Upper Reinforcement Roll 2-2 Lower Reinforcement Roll 3-1 Upper Work Roll Chock 3-2 Lower Work Roll Chock 4-1 Upper Reinforcement Roll Chock 4-2 Lower Reinforcement Roll Chock 5- 1 Incoming Project Block 5-2 Outgoing Project Block 5-3 Incoming Lower Project Block 5-4 Outgoing Lower Project Block 6-1 Incoming Upper Increase Bending Device 6-2 Outgoing Upper Increase Bending Device 6- 3 Incoming Lower Increase Bending Device 6-4 Outgoing Lower Increase Bending Device 7-1 Incoming Upper Decrease Bending Device 7-2 Outgoing Upper Decrease Bending Device 7-3 Incoming Lower Decrease Bending Device 7- 4 Outgoing lower decrease bending device 8-1 Entry-side reinforcing roll balance device -2 exit side rolls balancing device 9 housing 10 the material to be rolled 11 screw down device 12 housing window

Claims (6)

A metal plate rolling mill having a pair of upper and lower work rolls and a pair of upper and lower reinforcing rolls that respectively support these,
A hydraulic cylinder that applies an incremental bending force to each of the upper and lower work rolls is provided in a project block that protrudes inside the rolling mill housing,
The rolling direction force applied to the lower work roll body is supported by the contact surface between the project block and the lower work roll chock,
A rolling mill for a metal sheet, wherein a rolling direction force applied to the upper work roll body is supported by a contact surface between a rolling mill housing window and an upper work roll chock located above the project block.   The hydraulic cylinder that applies an increase bending force to the upper work roll and the hydraulic cylinder that applies an increase bending force to the lower work roll are disposed in different positions on the plan view in the project block. The metal sheet material rolling mill according to claim 1.   The metal plate material rolling machine according to claim 1 or 2, wherein a hydraulic cylinder that applies a decrease bending force to the upper work roll is disposed in the upper reinforcement roll chock of the upper reinforcement roll.   The hydraulic cylinder for applying a decrease bending force to the lower work roll is provided in a lower reinforcement roll chock of the lower reinforcement roll or a second project block installed below the project block. The metal plate material rolling machine according to any one of 1 to 3. A method for rolling a metal sheet using the rolling machine for a metal sheet according to claim 3,
Before starting rolling, both the increase bending force and the decrease bending force are applied, and the roll bending force corresponding to the roll balance force is applied to the work roll chock as a resultant force.
After that, at the start of rolling, the increase bending force is changed to the work roll chock as a resultant force while changing the increase bending force while continuing the control of maintaining the decrease bending force during the predetermined rolling. Put it into action,
During rolling, performing the rolling so as to maintain the work roll bending force during the predetermined rolling,
After that, at the end of rolling, the increase bending force is changed, and the roll bending force corresponding to the roll balance force is applied to the work roll chock as a resultant force with the decrease bending force, and the rolling of the metal plate material is finished in this state. A method for rolling a metal sheet.   Measure the hydraulic pressure in the hydraulic cylinder that generates the decrease bending force or in the hydraulic piping connected to the hydraulic cylinder so that the roll bending force acting on the work roll chock as a resultant force becomes a predetermined value based on the measured value. 6. The method for rolling a metal sheet according to claim 5, wherein the increase bending force is controlled.

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