JPH10175009A - Thickness control method for continuous hot rolling mill - Google Patents

Abstract

(57) [Summary] [Problem] To control the thickness of a continuous hot rolling mill so that the thickness at the exit side of a final rolling mill can be set to a desired value even when a reduction amount of a rolling position or a rolling load is limited when a running distance is changed. I will provide a. SOLUTION: The rolling position correction amount or rolling load of a rolling mill is constantly monitored, and when those values reach a limit,
By correcting the target value of the thickness control of the rolling mill one upstream of the rolling mill, the thickness of the sheet on the exit side of the final rolling mill is set to a desired value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous hot rolling mill and, more particularly, to a method for controlling the thickness of a continuous hot rolling mill for setting the exit side thickness of a final rolling mill to a proprietary value.

[0002]

2. Description of the Related Art FIG. 9 is a block diagram of a conventional continuous hot rolling mill. 1 is a rolling mill for rolling a rolled material 10 to obtain a plate having a desired thickness. Conventionally, in order to obtain a plate having a desired thickness, each rolling mill 1
In addition, a hydraulic pressure reduction device 2 is installed as a mechanism for arbitrarily setting the roll gap, and a thickness gauge detection plate thickness 7 from a thickness gauge 4 provided on an output side of each rolling mill is compared with a thickness control target value 6. Then, the thickness control deviation 8 is calculated, and the plate thickness control device 5 gives the hydraulic pressure reduction position correction amount 9 to the hydraulic pressure reduction control device 3 so as to eliminate the thickness control deviation 8, so that the roll gap of each rolling mill 1 is adjusted. Control.

[0003]

However, the roll gap of each rolling mill is independently controlled so that the thickness of the sheet on the outlet side of each rolling mill becomes a target value given from a setting calculator (not shown). However, the output side thickness of the upstream rolling mill is the thickness of the entrance side of the downstream rolling mill, and the power for rolling the sheet is determined by the difference between the thickness of the entrance side and the thickness of the exit side. (Power) changes and each rolling mill is affected by the rolling results of the other rolling mills. In general, in continuous hot rolling equipment, the thickness accuracy at the exit side of the most downstream rolling mill is a guaranteed value of the final product, but there is a predetermined error such as a roll gap setting error of each rolling mill. May physically limit the performance of the rolling mill. For example, as a result, it is said that the thickness control of the final rolling mill cannot be continued, and a case where the target thickness cannot be obtained as a practical problem occurs.

[0004] In recent years, an operation mode of changing a running strip thickness, which enables production of a thin sheet having difficulty in threading by changing the setting of the sheet thickness during rolling, has been increasing. Conventionally, the above-described sheet thickness control method has a problem that a method of continuing control or a method of switching a target value for a change in sheet thickness during running has not been provided.

The present invention has been made in view of the above circumstances, and provides a method for controlling the thickness of a continuous hot rolling mill capable of maintaining a target thickness on the exit side of a final rolling mill based on instructions from a setting computer. The purpose is to:

[0006]

In order to achieve the above object, the present invention provides a method for controlling the thickness of a continuous hot rolling mill by the following method. The invention corresponding to claim 1 is:
In a continuous hot rolling mill equipped with a plurality of rolling mills having a thickness gauge on the delivery side, the amount of reduction of the rolling position of the rolling mill is constantly monitored, and when the correction amount exceeds a limit value previously determined from the capacity of the rolling mill, the corresponding amount is corrected. When the thickness control target value on the upstream side of the rolling mill is corrected and the running thickness change start point reaches the rolling mill, the thickness control of the rolling mill is stopped, and the running thickness change end point is changed. By restarting the control of the thickness of the rolling mill when it reaches the output thickness gauge of the rolling mill, the thickness of the output side of the final rolling mill can be set to a desired value regardless of an error at the time of setting.

According to a second aspect of the present invention, in the first aspect, when the thickness control is restarted for the rolling mill, the end point of the change in the running strip thickness has reached the thickness gauge on the rolling mill exit side. The desired thickness can be obtained by changing the target value into a tapered shape from the thickness value detected by the thickness gauge to the target thickness value after changing the running thickness.

According to a third aspect of the present invention, there is provided a continuous hot rolling mill including a plurality of rolling mills each having a thickness gauge on an output side, wherein a rolling load is constantly monitored and a limit value determined in advance from the capacity of the rolling mill. When the load exceeds the rolling mill, the thickness control target value of the rolling mill one upstream of the rolling mill is corrected, and the thickness of the rolling mill is changed when the starting point of the change in the running distance reaches the rolling mill. The control is stopped, and the thickness control of the rolling mill is resumed when the end point of the change in the running thickness reaches the output thickness gauge of the rolling mill. The thickness can be set to a desired value.

According to a fourth aspect of the present invention, in the third aspect, when the thickness control is restarted for the rolling mill, the end point of the change in the running thickness has reached the thickness gauge on the rolling mill exit side. The desired thickness can be obtained by changing the target value into a tapered shape from the thickness value detected by the thickness gauge to the target thickness value after changing the running thickness.

According to a fifth aspect of the present invention, there is provided a continuous hot rolling mill including a plurality of rolling mills having a thickness gauge on an output side, wherein a hydraulic rolling position correction amount and a rolling load of the rolling mill are constantly monitored and the rolling load is monitored in advance. If the hydraulic pressure reduction position correction amount or the rolling load exceeds the limit value determined by the capacity of the rolling mill, the target value of the thickness control of the rolling mill one upstream of the rolling mill is corrected, and the starting point of the change in the running thickness is determined. Is set by stopping the thickness control of the rolling mill when reaching the rolling mill, and restarting the thickness control of the rolling mill when the end point of the change in the running thickness reaches the exit thickness gauge of the rolling mill. Regardless of the time error, the sheet thickness on the exit side of the final rolling mill can be set to a desired value.

According to a sixth aspect of the present invention, in the fifth aspect, when the thickness control for the rolling mill is restarted, the end point of the change in the running thickness reaches the thickness gauge on the rolling mill exit side. The desired thickness can be obtained by changing the target value into a tapered shape from the thickness value detected by the thickness gauge to the target thickness value after changing the running thickness.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram for explaining the principle of the present invention. The target value change control device 11 constantly monitors the hydraulic pressure reduction position correction amount 9 of the rolling mill, and when the limit value exceeds a limit value determined in advance from the capacity of the rolling mill, the target value change control output device 20 By modifying the thickness control target value 6 of the upstream rolling mill, the thickness at the entrance of the rolling mill is changed, and the balance between the thickness control target value at the entrance and the thickness at the exit side of the rolling mill is changed. The control by the thickness control device 5 of the rolling mill can be performed within a limit value determined from the capacity of the rolling mill, and a product having a desired thickness can be manufactured. Naturally, controlling the thickness of the sheet on the outlet side of the most downstream rolling mill to the target value is given priority. Therefore, in the present invention, the above-described change of the target value is performed from the downstream side to the thickness control device 5 on the upstream side. Will be

When the running distance is changed, the plate thickness is changed to a taper at a certain set time during rolling. When the plate thickness is controlled, the hydraulic pressure lowering position control device 3 which is an operation end of the control is used. In the present invention, as shown in FIG. 2, the target thickness change value of the thickness control is changed by the travel distance change unit by the target value change control device 11 when the travel distance is changed. Switch when passing through the rolling mill. In addition, during the period from when the running distance changing section reaches the rolling mill to when it passes through the thickness gauge on the rolling mill exit side, the sheet thickness control is turned off as shown in FIG. After the running distance changing section has passed through the thickness gauge on the rolling mill exit side, the sheet thickness control is turned on. Also, since the thickness gauge generally has a function of calibrating according to the target value of the thickness (a function of adjusting the weight of the deviation even if the deviation is the same), the running distance changing unit sets the target value of the thickness gauge to the distance. After passing through the thickness gauge on the exit side of the rolling mill, before turning on the thickness control, the strip is switched to the target thickness of the strip after the change in running distance.

At the time of changing the running distance, the thickness of the plate is changed to a target value of the reduced position after the changing of the running distance in a tapered shape at a certain set time during rolling. Does not always coincide with the delivery target value. In general, a target value of the rolling position such that the exit side plate thickness of the stud becomes the target value is calculated and set by a setting calculator (not shown). After the running distance change section has passed the thickness gauge on the rolling mill exit side,
When thickness control is turned on, if there is a large deviation between the output target value and the output plate thickness detected by the thickness gauge at that time, the amount of time integration of the deviation charged to the integral controller becomes large and the result An overshoot-like control trend occurs. In order to solve this and smoothly control the exit side sheet thickness to the target value of the rolling position after the running distance change, in the present invention, the end point of the running thickness change is set to the thickness gauge installed on the rolling mill exit side. When the monitor thickness control for the rolling mill concerned is resumed, the control is restarted while changing the tapered target value from the thickness value detected by the thickness gauge to the target value of the thickness after the change in running thickness when restarting the monitor thickness control for the rolling mill. I do.

FIG. 4 is a configuration diagram for carrying out the thickness control method of the present invention. A rolling mill 1 rolls a rolled material 10 to obtain a plate having a desired thickness. In order to obtain a plate having a desired thickness, each rolling mill 1 is provided with a hydraulic pressure reduction device 2 as a mechanism for arbitrarily setting a roll gap between the rolling mills 1 and a thickness gauge 4 provided on an output side of each rolling mill. The thickness control deviation 8 is calculated by comparing the thickness gauge detection plate thickness 7 with the thickness control target value 6, and the thickness control device 5 sends the hydraulic pressure reduction control 3 to the hydraulic pressure reduction control device 3 so as to eliminate the thickness control deviation 8. The roll gap of each rolling mill 1 is controlled by giving the rolling position correction amount 9. Target value change control device
11 constantly monitors the hydraulic press down position correction amount 9 of the rolling mill,
If the limit exceeds a predetermined value based on the capacity of the rolling mill, the target value change control output device 20 shown in FIG.

At the time of changing between running distances, the target value for thickness change 6 is switched by the running distance changing section when the running distance changing section passes through the rolling mill by the target value change control device 40 during running change. In addition, during a period from when the travel change section arrives at the rolling mill to pass through the thickness gauge on the exit side of the rolling mill, as shown in FIG. The control is turned off by the / off signal 41. After the running distance changing section has passed through the thickness gauge on the rolling mill exit side, the control is turned on as shown in FIG. In addition, since the thickness gauge generally has a function of calibrating with a thickness target value, the thickness gauge target value 42 is not changed after the travel distance changing unit has passed the thickness gauge on the exit side of the rolling mill. Before the control is turned on by the control change on / off signal 41 at the time of change of travel to the control device 5, the target thickness of the rolled material after the change of travel is switched.

Further, after the running distance changing unit passes the thickness gauge on the rolling mill exit side, when the control is turned on by the running time change control on / off signal 41 to the sheet thickness control device 5, the thickness is changed. Lock-on-memory the thickness feedback value detected by 4 in total and 5
FIG. 5 shows an embodiment in which a device 51 for restarting control while changing the target value in a tapered manner from the lock-on memory 50 to the target value of the sheet thickness after the change of the running sheet thickness is used is shown in FIG.

Next, a second embodiment of the present invention is shown in FIG. 1 is to roll the rolled material 10 by a rolling mill to obtain a plate having a desired thickness. In order to obtain a plate having a desired thickness, each rolling mill 1 is provided with a hydraulic pressure reduction device 2 as a mechanism for arbitrarily setting a roll gap between the rolling mills 1 and a thickness gauge 4 provided on an output side of each rolling mill. The thickness control deviation 8 is calculated by comparing the thickness gauge detection plate thickness 7 with the thickness control target value 6, and the thickness control device 5
Gives the hydraulic pressure reduction position correction amount 9 to the hydraulic pressure reduction control device 3 so as to eliminate the thickness control deviation 8 so that each rolling mill 1
Control of the roll gap. Load detection target value change control device
12 monitors the rolling load 30 of the rolling mill at all times, and when the load exceeds a limit value determined in advance from the capacity of the rolling mill as shown in FIG. The thickness control target value 6 of the upstream rolling mill is corrected.

At the time of changing the running distance, the target value for thickness change 6 is switched by the running distance changing section when the running distance changing section passes through the rolling mill by the target value changing control device 40 for changing the running distance. Further, during a period from when the travel change section arrives at the rolling mill to when the travel change section passes through the thickness gauge on the exit side of the rolling mill, control input / output during the travel change to the sheet thickness controller 5 is performed.
The control is turned off by the turn-off signal 41 as shown in FIG. After the running distance changing unit has passed the thickness gauge on the rolling mill exit side, the control is turned on to the sheet thickness control device 5 by the running time changing control on / off signal 41 as shown in FIG. Further, since the thickness gauge generally has a function of calibrating according to the target value of the thickness, the thickness gauge target value 42 is set to the target value change control device.
As shown in FIG. 8, after the travel change unit passes through the thickness gauge on the exit side of the rolling mill by 40 and before the control is turned on by the travel on / off change control on / off signal 41 to the sheet thickness control device 5, as shown in FIG. Then, switch to the target thickness of the strip after changing the running distance.

The following can also be performed as described with reference to FIG. 5 in the first embodiment. That is, after the travel change unit passes the thickness gauge on the rolling mill exit side, when the control is turned on by the monitor control on / off signal 41 at the time of travel change to the sheet thickness control device 5, the thickness gauge 4 Lock-on-memory the thickness feedback detected in step 50, and a device 51 that restarts control while changing the target value in a tapered manner from the lock-on memory 50 to the target value of the thickness after changing the running thickness It is of course possible to do so.

Next, a third embodiment of the present invention will be briefly described. This embodiment is a combination of the first embodiment and the second embodiment, and constantly monitors the hydraulic pressure reduction position correction amount and the rolling load of the rolling mill, and either or both of these values limit the limit value. If it exceeds, the above-mentioned thickness control is performed.

[0022]

As described above, according to the present invention, the rolling position correction amount or the rolling load of the rolling mill is constantly monitored regardless of the error at the time of setting, and when the value exceeds the limit value, the rolling mill is controlled. Since the target value of each of the upstream rolling mills is changed, the sheet thickness on the exit side of the final rolling mill can be set to a desired value.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram for explaining the principle of the present invention.

FIG. 2 is a timing chart showing a case where a hydraulic pressure reduction position correction amount reaches a limit and processing in that case.

FIG. 3 is a timing chart showing a case where the hydraulic pressure reduction position correction amount reaches a limit and processing in that case.

FIG. 4 is a configuration diagram for implementing a sheet thickness control method of the present invention.

FIG. 5 is a configuration diagram for implementing a lock-on-memory method.

FIG. 6 is a configuration diagram showing another embodiment of the present invention.

FIG. 7 is a timing chart showing a case where a rolling load is applied to a limit and processing in that case.

FIG. 8 is a timing chart showing a case where a rolling load is applied to a limit and a process in that case.

FIG. 9 is a configuration diagram showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Rolling machine 2 ... Hydraulic reduction device 3 ... Hydraulic reduction position control device 4 ... Thickness gauge 5 ... Thickness control device 11 ... Target value change control device 12 ... Load detection target value change control device 40 ... Target value at the time of change during running Change control device

Claims (6)

[Claims] In a continuous hot rolling mill having a plurality of rolling mills having a thickness gauge on an output side, a continuous rolling mill is used to keep the thickness of the output side of a final rolling mill to a desired value regardless of an error at the time of setting. The correction amount of the rolling position of the rolling mill is monitored, and when the correction amount exceeds a limit value determined in advance from the capacity of the rolling mill, the target value of the thickness control of the rolling mill one upstream from the rolling mill is corrected, and the running is performed. When the start point of the change in the thickness of the rolling mill reaches the rolling mill, the control of the thickness of the rolling mill is stopped. A method for controlling the thickness of a continuous hot rolling mill. 2. When the thickness control for the rolling mill is restarted, the thickness value detected by the thickness gauge when the end point of change in the running thickness reaches the thickness gauge on the exit side of the rolling mill. 2. The method for controlling a thickness of a continuous hot rolling mill according to claim 1, wherein the target value is changed into a tapered shape from the target value to the target value after the change in the running thickness. 3. In a continuous hot rolling mill having a plurality of rolling mills having a thickness gauge on the delivery side, in order to make the thickness of the delivery side of the final rolling mill a desired value regardless of an error at the time of setting. The rolling load of the rolling mill is monitored, and when the load exceeds a limit value determined in advance from the capacity of the rolling mill, the target value of the thickness control of the rolling mill one upstream of the rolling mill is corrected, and the running is performed. When the start point of the change in the thickness of the rolling mill reaches the rolling mill, the control of the thickness of the rolling mill is stopped. And a method for controlling the thickness of a continuous hot rolling mill. 4. When the thickness control is restarted for the rolling mill, the thickness value detected by the thickness gauge when the running thickness change end point reaches the thickness gauge on the exit side of the rolling mill. 4. The method for controlling a thickness of a continuous hot rolling mill according to claim 3, wherein the target value is changed in a tapered shape from the target value to the target value after the change in the running thickness. 5. In a continuous hot rolling mill having a plurality of rolling mills having a thickness gauge on the delivery side, in order to keep the thickness of the delivery side on the final rolling mill to a desired value regardless of an error at the time of setting. When the hydraulic rolling position correction amount and the rolling load exceed the limit value determined in advance from the capacity of the rolling mill and the hydraulic rolling position correction amount and the rolling load exceed the limit value determined in advance by the rolling mill, the rolling mill of one upstream side from the rolling mill concerned. In addition to correcting the target value of the thickness control, the thickness control of the rolling mill is stopped when the start point of the running thickness change reaches the rolling mill, and the end point of the running thickness change is set to the exit side thickness of the rolling mill. A sheet thickness control method for a continuous hot rolling mill, wherein the sheet thickness control of the rolling mill is restarted when the total number reaches a total value. 6. When the thickness control for the rolling mill is restarted, when the end point of the change in the running thickness reaches the thickness gauge on the exit side of the rolling mill, the thickness value detected by the thickness gauge. 6. The method for controlling the thickness of a continuous hot rolling mill according to claim 5, wherein the target value is changed in a tapered shape from the target value to the target value after the change in the running thickness.