JP2957402B2 - Meandering control method in hot rolling - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a meandering control method in hot rolling.

[0002]

2. Description of the Related Art Conventionally, in the meandering control of a rolling mill, a meandering amount of the rolling mill is indirectly detected based on a difference between output signals of load cells installed on the working side and the driving side of the rolling mill, and the signal is detected. The meandering is controlled by adjusting the amount of reduction of the work side and drive side reduction systems on the basis of the above. However, in this method, the change in the load acting on both load cells due to the meandering of the rolling mill is to detect the change when the rolled material has already passed through the plate, and a timing delay occurs to control the true meandering signal. In fact, it has not been put to practical use.

Therefore, as disclosed in JP-A-59-191510, the shift amount of the rolled material on the entry side of the rolling mill is directly detected, and the work-side and drive-side press-down devices are controlled in accordance with this amount. The meandering of the rolling mill is prevented by changing the load cells on the working side and the drive side. In addition, special fair 3
As disclosed in -75242, a detector is provided on the working side and the driving side on the entry side of the rolling mill so that it can have a number of imaging elements that form light at substantially equal intervals in the width direction of the rolled material, A calculator for calculating the amount of meandering of the rolled material from the difference between the output signals of the detectors and a setter for providing a target position of the rolled material are provided, and the output signal of the calculator is compared with the target signal of the setter. An apparatus and an apparatus for processing a signal obtained by the apparatus and outputting the processed signal as a rolling correction signal on the working side and the driving side, and changing a roll gap between the working side and the driving side by the rolling reduction signal.

FIG . 5 is an explanatory diagram showing a conventional control system based on the output of a load cell . A load detector 4 such as a load cell is provided on each of the working side and the driving side of each stand, and prediction is performed under leveling control based on a difference load (ΔF = F _DS −F _WS ) between the working side and the driving side. The load is calculated, the reduction values on the working side and the drive side are calculated, and a command is issued to the reduction device 3. FIG. 6 shows a conventional example in which a meandering detector is installed on the entrance side of a leveling stand and a signal is processed on the entrance side of the rolled material to level the nearest downstream stand, as disclosed in Japanese Patent Publication No. 3-75242. It is explanatory drawing which shows the meandering control system of FIG. As shown in FIG. 6, after the tail end of the rolled material 7 has passed the position of the meandering detector 8, the rolled material 7 is no longer present, and the subsequent meandering detection and measurement cannot be performed. Is shown.

[0005]

As described above, FIG.
A method of changing the roll gap between the working side and the driving side of the stand by the difference load signal of the stand as shown in FIG. 6 or installing a meandering detector on the entrance side of the stand to be leveled as shown in FIG. In the method of performing signal processing at the entry side and leveling the downstream stand, the control timing is late, so that it is not possible to control the true meandering signal, and the tail end of the rolled material passes through the detector position In such a case, there is a problem that proper control cannot be performed.

[0006]

SUMMARY OF THE INVENTION The present invention advantageously solves the above-mentioned problems of the prior art. The gist of the present invention is to use a meandering detector of a hot finishing mill. In the meandering control, the signal of the meandering detector is correlated with the difference load signal of the stand downstream from the meandering detector before the tail end of the threaded sheet passes through the meandering detector, and a correlation formula is created to exit the meandering detector. Meanwhile, the differential load signal of the downstream stand is processed using the above-mentioned correlation equation until the roll gap between the working side and the drive side is changed until the sheet leaves the downstream stand. It is in.

Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory view showing a draft control mechanism of a hot rolling finishing mill. As shown in FIG. 1, the rolling mill has four work rolls including upper and lower work rolls 2 for biting and rolling a sheet material, and upper and lower backup rolls 1 for pressing the upper and lower work rolls 2 from above and below and pressing. Machine. Then, a rolling device 3 and a work roll 2 for applying a rolling load provided on a roll chock of a backup roll.
A roll-down position detector for detecting the roll gap between the edge portions and a load detector 4 for detecting the roll-down load are disposed on each of the working side and the drive side. 3 and a load detector 4 for detecting a rolling load, for example, a control device 5 for detecting a differential load and a roll gap between the working side and the driving side by a load cell and changing the roll gap by an arithmetic unit 6. This is to change the work side and drive side roll gaps.

FIG. 2 is a diagram showing the relationship between the actual meandering amount and the meandering amount converted to the difference load. As shown in FIG. 2, in the relationship between time and the meandering amount from the tail end mill stand F ₅ Shirinuke of the rolled material, actual meandering amount between rolling stands F ₆ and F ₇ are different load calculation value of the rolling stand actually occurs a delay from the difference between load calculation value at it is, but rolling stands F ₇ shows substantially the same value as. That is, the rolling stands F ₆ and F ₇
Meandering amount between the and F ₆ shows that a correlation. Moreover, the response of the difference load change of the rolling stand F ₇ it can be seen that shows the considerably slower response than the actual meandering phenomenon.

FIG . 3 is an explanatory diagram showing a control system of a rolling stand showing an embodiment according to the present invention. In FIG. 3 , a meandering detector 8 is provided between the rolling stands _Fi and _Fi-1, and the signal is processed by a signal processor 9 of the meandering detector 8 to perform the _Fi-1 stand, the _Fi-2 stand, and the F _-1 stand. The rolling device 3 for applying a rolling load on the working side and the driving side of each stand of the ( _{i + 1)} stand is controlled to reduce the roll gap to perform leveling. In this case, the meandering detector can more sensitively detect the difference load signal.
Even the trailing edge of the rolled material 7 at the _i-1 stand or the Fi _-2 stand can be measured by the meandering detector. However, after Shirinuke of the rolled material 7 in F _i-2 stand no control of F _i-2 stand. All of these can be controlled simultaneously, but the roll gap can be changed independently or simultaneously.

[0010] Ya F _i stand after Shirinuke of meandering detector 8
As shown in FIG. 4 , the F _{i + 1} stand is controlled by arranging a meandering detector 8 between F _i and F _i-1 of the rolling stand so that the tail end of the rolled material 7 passes through l _1. F _i correlates the difference load and meandering detector signals of the stand, seeking working side relationship of the difference △ δ = a × △ F + b of the amount of meandering of the driving side each synchronously controlled,
While passing through the rolled material tail and l ₂ is for controlling the leveling of F _i stand using the above equation. However, △
F is Ru difference load der of the driving side and the working side of the F _i stand.

[0011]

As described above, according to the present invention, the meandering amount of the rolled material on the entering side of the rolling mill is determined by the differential load signal on the working side and the drive side of the upstream stand after the meandering detector bottom end.
Uses the correlation formula between the difference load signal and the meandering detection signal to control the roll gap on the working side and the drive side of the downstream stand so that true meandering corresponding to a slower response than the actual meandering phenomenon can be controlled. Thus, bending problems due to poor leveling of the rolled material are reduced, stable plate passing property and shape quality can be ensured, and excellent effects such as improvement in product yield can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a reduction control mechanism of a hot rolling finishing mill;

FIG. 2 is a diagram showing a relationship between an actual meandering amount and a difference load calculation meandering amount;

FIG. 3 is an explanatory view showing a control system of a rolling stand according to another embodiment of the present invention,

FIG. 4 is an explanatory view showing a control system of a rolling stand showing still another embodiment according to the present invention.

FIG. 5 is an explanatory diagram showing a conventional rolling stand control system,

FIG. 6 is an explanatory diagram showing a conventional meandering control system.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 backup roll 2 work roll 3 reduction device 4 load detector 5 control device 6 arithmetic device 7 rolled material 8 meandering detector 9 signal processing device

──────────────────────────────────────────────────の Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B21B 37/68

Claims (1)

(57) [Claims] In a meandering control using a meandering detector of a hot finishing mill, a signal of the meandering detector and a differential load of a stand downstream from the meandering detector before the tail end of the threaded sheet passes through the meandering detector. The correlation between the signals is calculated, a correlation formula is created, and the difference load signal of the downstream stand is processed by using the above correlation formula from the meandering detector to passing through the downstream stand. A meandering control method in hot rolling characterized by changing a roll gap.