JP4226516B2 - How to change the pass schedule in a plate rolling machine - Google Patents

Description

  The present invention relates to a method for changing a pass schedule in a thick plate rolling apparatus.

Conventionally, a number of techniques have been disclosed in order to improve productivity when continuously rolling a plurality of rolled materials with a thick plate rolling apparatus.
In Patent Document 1, in continuous rolling of the rolled material and the preceding rolled material that is rolled prior to the rolled material in a thick plate rolling apparatus, the progress of the preceding rolled material or the progress of the material The deviation of the progress is monitored at a predetermined timing, and when the deviation exceeds a predetermined value, the pitch between the preceding rolled material and the rolled material (time pitch) is increased or decreased, for example, by increasing or decreasing the number of rolling of the rough rolling mill. ) Has been disclosed.

Consider an example in which this technique is applied to rolling of a pass schedule as shown in FIG.
In this pass schedule, the preceding rolled material is rolled a predetermined number of times by a rough rolling mill, and then cooled to a predetermined temperature by a cooling device disposed on the downstream side of the rough rolling mill, and further disposed on the downstream side of the cooling device. Rolling is performed a predetermined number of times by a finishing mill. The rolled material is also rolled after a predetermined time of the preceding rolled material in the same process as the preceding rolled material.
FIG. 11 shows the result of applying the technique of Patent Document 1 when the preceding rolled material having such a pass schedule is delayed for some reason. That is, in order to cope with the delay of the preceding rolled material, the rolled material is kept waiting at the cooling device in a state where water cooling is stopped, and the time pitch between the preceding rolled material and the rolled material in the finish rolling mill is minimized. Yes. In other words, the rear end portion of the preceding rolled material and the front end portion of the rolled material are in a state of being closest to each other as long as there is no hindrance to rolling.

Further, as shown in FIG. 12, the number of rolling in the rough rolling mill is increased so as to correspond to the delay time of the preceding rolling material, and the time pitch between the preceding rolling material and the rolling material in the finishing rolling mill is minimized. It is also possible to do so. In this case, the number of rolling passes in the finish rolling mill is reduced.
Japanese Patent Publication No. 8-18057 (pages 3 to 5, FIG. 1)

However, the technique of “maintaining the time pitch between the preceding rolled material and the rolled material to the shortest” described in Patent Document 1 is not effective for all plate rolling.
For example, in recent years, along with tightening of user needs, is simply finish rolling but also the delivery side temperature of the final pass to match the target value, the required rolling of Ru to match the target value of the plate temperature in the rough rolling step ing.
For example, FIG. 2 is present the lines Upa scan schedule water cooling for rough rolling midway in the rolled material. In this rolling, as shown to A of FIG. 13, the case where a preceding rolling material advanced earlier than planned is considered.

  In the technique described in Patent Document 1, in order to minimize the time pitch between the rolled materials within a range that does not cause interference, the rolled material that is not subjected to temperature adjustment in the cooling device during rough rolling is used. Then, it is instructed to transfer to the finishing mill (B in FIG. 13). However, since the rolled material is transferred to the finish rolling mill at a stage thicker than the cooling execution plate thickness, it is necessary to reach the cooling execution plate thickness during rolling in the finishing rolling mill and perform temperature adjustment by air cooling. Arise. However, the cooling by air cooling takes much time compared to the time of water cooling, and the finish rolling end time becomes very late, and the application of the technique of Patent Document 1 does not contribute to the improvement of productivity at all.

In order to avoid this situation, even if the rolled material after finish rolling is fed back to the cooling device and cooled with water, rapid cooling is performed and inconveniences such as distortion occur in the rolled material. .
Therefore, in view of the above problems, the present invention is a thick plate capable of improving productivity by finishing finish rolling of the rolled material earliest even if the pass schedule of the preceding rolled material changes. An object of the present invention is to provide a method for changing a pass schedule in a rolling mill.

In order to achieve the above object, the present invention takes the following technical means.
That is, the technical means for solving the problems in the present invention is a thick plate rolling device having a rough rolling mill and a finish rolling mill, and the rolled material and the preceding rolled material that is rolled prior to the rolled material, In the continuous rolling of the two rolled materials, when the pass schedule of the preceding rolled material fluctuates, the path schedule changing method of the thick plate rolling apparatus that changes the pass schedule of the rolled material accordingly, A pass schedule in which the finish rolling finish time of the rolled material is the earliest is calculated, and the pass schedule obtained by this calculation is used as the pass schedule of the rolled material.

According to this, even when the pass schedule of the preceding rolled material changes, the rolled material is transferred to the finishing mill so that the finish rolling finish time of the rolled material becomes the earliest, and the rolling is performed in a short time. The rolling of the material can be finished, and the productivity can be improved.
The calculation of the pass schedule may be performed when the preceding rolled material deviates from the scheduled pass schedule by a certain amount or more. Moreover, since the transfer timing from the rough rolling mill to the finish rolling mill is calculated, it must be performed before the rough rolling of the rolled material is completed. That is, it is necessary to be in a situation where rough rolling is performed.

Furthermore, the calculation of the pass schedule involves calculating the timing for transferring the rolled material from the roughing mill to the finishing mill and changing the pass schedule accordingly. This should be done when the rolling material is present between the rolling mill and the finish rolling mill. The rolling material is positioned on the downstream side of the rolling mill in the odd-numbered pass when the first rolling in the rough rolling mill is considered as the first pass.
From these, the calculation of the transfer timing is performed under the condition that the rolling material is being rolled by a roughing mill and the path schedule fluctuation of the preceding rolling material reaches a certain amount or more, and the odd number of passes of the rolling material. This is done at the end of each eye.

According to this, it becomes possible to reliably capture the time when the necessity of changing the pass schedule of the rolled material occurs and to determine the transfer timing.
As a concept of pass schedule calculation, first, assuming that the advance of the preceding rolled material 9 is detected at the position p4 in FIG. 3, first, rolling of the rolled material 8 after the current pass is performed. It is assumed that the roughing is performed in the roughing mill 5 until the thickness reaches the minimum thickness in the roughing mill 5 given in advance. Assuming that the rolling path at which the position p5 in FIG. 3 is the minimum plate thickness, five paths p6, p7, p8, p9, and p10 in FIG. 3 are the assumed paths.

Next, it is assumed that the transfer from the roughing mill to the finish rolling mill is performed between the passes of p6 in FIG. 3, and the pass rolling schedule of the rolled material is recalculated and at the same time the finish rolling of the material is transferred at p6. An expected completion time T6 is calculated.
Similarly, if the path schedule of the material is recalculated between the paths p7, p8, p9, and p10 in the figure under the condition that transfer is performed between the paths as indicated by the dotted arrows in FIG. At the same time, predicted times T7, T8, T9, and T10 of completion of finish rolling of the material when transferred between the passes are calculated.

Next, from T6 to T10, the one with the earliest completion time (T8) is selected in a range in which the preceding rolled material and the rolled material do not interfere with each other, so that the odd-numbered path becomes the transfer timing. What is necessary is just to change a rolling pass schedule.
That is, the calculation of the pass schedule is performed using the roughing mill after the current pass until the plate thickness of the rolling material reaches the minimum thickness in the roughing mill given in advance. Assuming that, the finish rolling end time is calculated when the rolled material is transferred to the finish rolling mill between each odd number of passes, and among these calculated finish rolling end times, the earliest finish rolling end time is calculated. The odd number path to be realized may be the transfer timing of the rolled material from the rough rolling mill 5 to the finishing rolling mill.

According to this technical means, it is possible to calculate the transfer timing that realizes the earliest finish rolling end time without using a difficult mathematical method such as an evaluation function.
The most preferable technical means for solving the problem in the present invention is a thick plate rolling device having a roughing mill and a finish rolling mill, and the rolling material and the preceding rolling rolled before the rolling material. In continuously rolling two rolled materials with a material, when the pass schedule of the preceding rolled material fluctuates, the path schedule changing method of the thick plate rolling apparatus changes the pass schedule of the rolled material accordingly, A pass schedule in which the finish rolling finish time of the rolled material is the earliest is calculated, and the pass schedule obtained by this calculation is used as the pass schedule of the rolled material, and the calculation of the pass schedule is performed by the rolling When the material is being rolled by a roughing mill and the fluctuation of the pass schedule of the preceding rolled material reaches a certain amount or more, the odd-numbered pass of the rolled material And the calculation of the pass schedule is performed when the rolling after the current pass is performed by the roughing mill until the thickness of the rolled material reaches the minimum thickness in the roughing mill given in advance. Assuming that the finish rolling end time is calculated when the rolled material is transferred to the finish mill between each odd number of passes, and the earliest finish rolling end time among the calculated finish rolling end times is realized. The odd-numbered path to be used is the transfer timing of the rolled material from the roughing mill to the finishing mill.

  According to the present invention, in the plate rolling apparatus for continuously rolling the preceding rolled material and the rolled material, even if the pass schedule of the preceding rolled material fluctuates, finish rolling of the rolled material is finished earliest. It is possible to improve productivity.

Hereinafter, the pass schedule changing method of the thick plate rolling device 1 according to the present invention will be described with reference to the drawings.
FIG. 1 shows an outline of a thick plate rolling apparatus 1. The thick plate rolling apparatus 1 has a heating furnace 2 for heating a rolled material on the upstream side, and a pair of downstream side of the heating furnace 2. A rough rolling mill (coarse mill) 5 including a work roll 3 and a pair of backup rolls 4 is provided. A cooling device 6 that adjusts the temperature by spraying water or air on the rolled material is disposed on the downstream side of the rough rolling mill 5. A pair of work rolls 3 and a pair of work rollers 3 are disposed on the downstream side of the cooling device 6. A finishing rolling mill (finishing mill) 7 having a backup roll 4 is provided.

In the thick plate rolling device 1, two rolled materials, the rolled material 8 and a preceding rolled material 9 that is rolled prior to the rolled material 8, are continuously rolled based on a preset pass schedule. It is like that.
FIG. 2A shows a pass schedule of the preceding rolled material 9, and the preceding rolled material 9 heated to a predetermined temperature in the heating furnace 2 is introduced into the roughing mill 5, and reverse rolling is performed for a plurality of passes. Then, after cooling with the cooling device 6, it is transferred to the finish rolling mill 7 and reverse rolled, and the plate rolling is completed.

The rolled material 8 is also conveyed from the heating furnace 2 to the rough rolling mill 5 and reverse-rolled so as to follow the preceding rolled material 9 as shown in FIG. The rolled material 8 is a rough rolling step, the plate thickness of the plate temperature specified in the thickness range of implementing the rough rolling is performed a rolling of Ru to match the target value, once in the middle of the rough rolling The temperature is adjusted by being conveyed to the cooling device 6. Thereafter, rolling is performed again for a predetermined pass by the rough rolling mill 5, the temperature is adjusted by the cooling device 6, and then rolling is performed by the finish rolling mill 7.
In the description of the present embodiment, the transfer of the rolled materials 8 and 9 to the processing of the finish rolling mill 7 after the processing of the rough rolling mill 5 is referred to as “transfer”. Therefore, when it moves away from the rough rolling mill 5 to the cooling device 6 and returns to the rough rolling mill 5 again, it is interpreted as processing in the rough rolling mill 5 and expressed as “conveyance” instead of transfer. To do.

When rolling the rolled material 8, there is a case where the rolling results of the prior rolling material 9 or displaced from the initial pass schedule for some reason. At that time, the pass schedule in which the finish rolling finish time of the rolled material 8 becomes the earliest is recalculated, and the pass schedule obtained by this calculation is set as the pass schedule of the rolled material 8.
In addition, it is a very important matter to detect at which timing that the preceding rolled material 9 is delayed or advanced by a certain amount and to recalculate the pass schedule based on it.
In the present embodiment, the process is performed when the preceding rolled material 9 deviates from a scheduled pass schedule by a predetermined amount or more.

Moreover, since the transfer timing from the rough rolling mill 5 to the finish rolling mill 7 is calculated, it is performed before the rough rolling of the rolled material 8 is completed. That is, it is necessary to be in a situation where rough rolling is performed. Furthermore, it should be performed aiming at the time when the rolling material 8 exists downstream of the rough rolling mill 5, in other words, between the rough rolling mill 5 and the finish rolling mill 7. The rolling material is located on the downstream side of the rolling mill in the odd-numbered pass when the first rolling in the rough rolling mill 5 is considered as the first pass.
Organize
(A) Between passes after the time when the amount of deviation from the initial pass schedule of the preceding rolled material 9 reaches a certain value or more (b) The lower limit value of the thickness (transfer thickness) of the rolled material 8 when it is transferred Between the passes as described above (c) The pass schedule is reviewed between passes satisfying all of the passes at the end of odd-numbered passes when the first pass of rough rolling is used as a reference.

The condition (a) is, for example, calculating predicted values of the processing completion time of the preceding rolled material 9 in each equipment, that is, the cooling device 6 and the finish rolling mill 7 on the downstream side of the rolled material 8, respectively. It is preferable to select the largest absolute value among the differences from the planned value and to make a judgment when it reaches a certain value or more.
In performing the recalculation of the pass schedule, it is assumed that the rolled material 8 is all carried out by the roughing mill 5 after the current pass, and the finish rolling finish time when the rolling material 8 is transferred to the finishing mill 7 between the respective odd passes. The odd-numbered path that realizes the earliest finish rolling end time among these calculated finish rolling end times is used as the transfer timing of the rolled material 8 from the rough rolling mill 5 to the finish rolling mill 7. ing.

For example, as shown in FIG. 3, upon which rolling the rolled material 8, the preceding rolled material 9 Consider the case advanced as A in FIG. 3 (two-dot chain line initial pass schedule).
Assuming that the advance of the preceding rolled material 9 is detected at the position p4 in FIG. 3, first, the rough rolling mill 5 in which the thickness of the rolled material 8 is given in advance for rolling after the current pass of the rolled material 8. It is assumed that the roughing is performed by the roughing mill 5 until the minimum sheet thickness is reached. Assuming that the rolling path at which the position p5 in FIG. 3 is the minimum plate thickness, five paths p6, p7, p8, p9, and p10 in FIG. 3 are the assumed paths.

Next, assuming that the transfer from the roughing mill 5 to the finish rolling mill 7 was performed between the passes of p6 in FIG. 3, the rolling schedule in the case where the rolling schedule 8 was recalculated and transferred at p6 was recalculated. An expected time T6 for completion of finish rolling of the material is calculated.
Similarly, between the passes of p7, p8, p9, and p10, the rolled material is transferred between the respective passes under the condition that the transfer is performed between the passes as shown by the dotted arrows in FIG. In this case, finish rolling completion prediction times T7, T8, T9, and T10 are calculated. Naturally, in the transfer in each pass, the transferred rolled material 8 has a minimum necessary distance from the preceding rolled material 9.

For example, it is assumed that T8 is the earliest time among T6 to T10. In that case, the pass schedule of the rolled material 8 is recalculated on the condition that the transfer is performed at p8, and the calculation result is set as a new pass schedule (B in FIG. 3 and B in FIG. 4).
On the other hand, when a control method is used such that the time pitch between the preceding rolled material 9 and the rolled material 8 is the shortest with respect to the deviation of the preceding rolled material 9, the result is as shown in FIG. In particular, the final rolling completion time is delayed. That is, the technique according to the present invention significantly shortens the time required to complete the finish rolling as compared with the shortest pitch control method.

By using this pass schedule recalculation method, it is possible to easily recalculate the pass schedule by determining the transfer timing that achieves the earliest finish rolling end time without using difficult mathematical methods such as evaluation functions. It becomes possible.
In FIG. 5, there is shown another example of a path schedule. In this pass schedule, the rolled material 8 is not cooled by the cooling device 6 but directly transferred from the rough rolling mill 5 to the finishing rolling mill 7, and the temperature is adjusted by air cooling in the finishing rolling mill 7.
In this pass schedule, as shown in FIG. 6A, consider a case where the preceding rolled material 9 is delayed for some reason (the initial pass schedule is a two-dot chain line). In order to cover such a delay of the preceding rolled material 9, a case where a pass schedule that minimizes the time interval between the preceding rolled material 9 and the rolled material 8 is calculated is shown by a broken line in FIG. C) (application of the prior art).

In this case, the rolled material 8 is in a waiting state for a predetermined time in the roughing mill 5 in order to make the interval pitch with the delayed preceding rolled material 9 predetermined, and then transferred to the finishing mill 7 and rolled.・ Cooling starts. Eventually, the finish rolling finish time is delayed.
On the other hand, when the technique according to the present invention is applied, the pass schedule of the rolled material 8 is as shown in FIG. In this pass schedule, the rolling material 8 is not cooled in the vicinity of the finish rolling mill 7 but is cooled at the position of the cooling device 6 in order to make the finish rolling finish time the earliest. Therefore, an efficient pass schedule can be established without creating a waiting time for the rolled material 8.

The path schedule changing method described above is calculated by the control means 10 shown in FIG. The control means 10 is composed of a process computer (process computer) or the like, and the calculation result is reflected in the thick plate rolling apparatus 1.
For example, it is assumed that a pass schedule as shown in FIG. 7 is set in the rolling process of the preceding rolled material 9 and the rolled material 8.
In the control means 10, the schedule change trigger process shown in FIG. 8 is to monitor the amount of deviation of the preceding rolled material 9 with respect to the pass schedule shown in FIG. When it is determined that the value exceeds the threshold value α, the schedule change trigger process ends, and the schedule change process (FIG. 9) that performs recalculation of the pass schedule of the rolled material 8 is started.

In the schedule change trigger process, first, a time rTsc (predicted value) at which the cooling process for the preceding rolled material 9 in the cooling facility is completed is calculated. At this time, if the cooling process has already been completed, the actual time is collected. (S71)
Next, the time rTsf at which the reverse rolling in the finish rolling mill 7 for the preceding rolled material 9 is completed is predicted. (S72)
Based on the obtained values, the deviation dTsc = | Tsc · rTsc | of the cooling processing completion time is obtained, and the deviation dTsf = | Tsf · rTsf | of the finishing mill processing completion time is obtained. Tsc is the completion time of the cooling process in the initial pass schedule, and Tsf is the completion time of the finish rolling mill process in the initial pass schedule. (S73, S74)
As described above, the largest dTs (= max (dTsc, dTsf)) is extracted from the obtained deviation dTsc of the cooling processing completion time and the deviation dTsf of the finish rolling mill completion time, and this dTs is extracted as the preceding rolling material 9 The amount of deviation in the pass schedule. (S75)
The pass schedule deviation amount dTs is compared with a predetermined threshold value α. If dTs> α, a “schedule change process” for changing the pass schedule of the rolled material 8 is started. (S77)
The schedule change process is performed according to the procedure shown in FIG.

First, an interval between paths (p1 to pk) that satisfies the following condition is obtained. (S81)
(A) After the scheduled change of the preceding rolled material 9 reaches a certain value or more (b) The thickness of the rolled material 8 is given to the rolled material 8 (the thickness at the time of transfer) (C) At the end of the odd pass when the first pass of rough rolling is used as a reference Next, from the rough rolling mill 5 to the finishing mill in a pi pass (if i = 7, p7 pass) , The pass schedule of the rolled material 8 is recalculated, and the predicted value of the finish rolling completion time (Ti) of the rolled material 8 is calculated based on this result. (S82, S83)
The above process is repeated between i = 1 to k to calculate T1 to Tk.

The smallest one of these T1 to Tk is selected, and the interval between the corresponding passes is set as the transfer timing, and the pass schedule of the rolled material 8 is changed at the determined transfer timing. (S84, S85)
The present invention is not limited to the above embodiment.
Namely, the present invention is applicable to a case where the rolled material 8 does not perform temperature adjustment.

It is a figure which shows the outline of a thick plate rolling apparatus. Is a diagram showing the planned pass schedule of rolling performing temperature control. It is a figure explaining the change method of the path schedule concerning this invention. It is a figure which shows the result of having changed the pass schedule of FIG. 2 (when a preceding rolling material advances). Is a diagram showing the planned pass schedule of rolling performing temperature control. It is a figure which shows the result of having changed the pass schedule of FIG. 5 (when a preceding rolling material is delayed). It is the figure which showed the detail of the plan path schedule. It is a flowchart of a schedule change trigger process. It is a flowchart of a schedule change process. It is the figure which showed the typical pass schedule in a plate rolling apparatus. It is a figure which shows the result of having changed the pass schedule of FIG. 10 using a prior art (when a preceding rolling material is delayed). It is a figure which shows the result of having changed the pass schedule of FIG. 10 using a prior art (when a preceding rolling material is delayed). It is a figure which shows the result of having changed the pass schedule of FIG. 2 using a prior art (when a preceding rolling material progresses).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thick plate rolling apparatus 5 Rough rolling mill 7 Finishing rolling mill 8 The said rolling material 9 Prior rolling material

Claims (1)

In the thick plate rolling machine having a rough rolling mill and a finish rolling mill, in order to continuously roll the two rolled materials of the rolled material and the preceding rolled material rolled prior to the rolled material, the preceding rolling is performed. In the path schedule change method of the plate rolling apparatus that changes the pass schedule of the rolled material accordingly when the pass schedule of the material changes,
Calculating a pass schedule in which the finish rolling finish time of the rolled material is the earliest, and setting the pass schedule obtained by this calculation as the pass schedule of the rolled material ,
The calculation of the pass schedule is performed at every end of the odd-numbered pass of the rolled material in a situation where the rolled material is being rolled by a roughing mill and the fluctuation of the pass schedule of the preceding rolled material reaches a certain amount or more. I,
In addition, the calculation of the pass schedule is based on the assumption that the rolling after the current pass is performed in the roughing mill until the thickness of the rolled material reaches the minimum thickness in the roughing mill given in advance. The finish rolling end time when the rolled material is transferred to the finishing mill between the odd-numbered passes is calculated, and among the calculated finish rolling end times, the odd-numbered pass that realizes the earliest finish rolling end time is calculated. A method for changing a pass schedule of a thick plate rolling apparatus, characterized in that it is a transfer timing of a rolled material from a rough rolling mill to a finishing rolling mill .

Images