JPH06328111A - Method for controlling leveling in hot rolling - Google Patents

Abstract

PURPOSE:To provide a method for accuratly controlling the camber of sheet by which the camber and meandering are prevented by leveling control of hot rolling that hysterisis compensation is added. CONSTITUTION:In leveling control of hot rolling, hysterisis corrections are respectively added to the load cell load on the work and drive sides of a rolling roll and rolling forces on the work and drive sides of the rolling roll are respectively corrected. Then, by executing hysterisis compensation, the precision of leveling control is improved and stable passableness of strip and shape quality are secured.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, as a meandering control device of a rolling mill applied to a rolling mill for rolling slabs such as hot strip mills and plate mills, as disclosed in Japanese Patent Publication No. 3-75242, the detected end of the rolled material is detected. The meandering amount of the rolled material is obtained from the position of the part, and the reduction correction signal on the working side and the driving side is obtained from the difference between this meandering amount and the target value. The roll gap on the side is corrected.

Further, as a rolling mill bending control method for solving the phenomenon that the rolled material on the delivery side of the rolling mill does not go straight but bends in either the left or right direction, as disclosed in Japanese Patent Application Laid-Open No. 58-159911, The plate bending is detected using a plate width measuring device, the plate bending amount is calculated according to this detection signal, and the plate bending correction amount is calculated according to this plate bending amount. It is known to correct plate bending of rolled metal by adjusting the opening.

Further, as a hysteresis compensation method, as in Japanese Patent Publication No. 63-1129, an automatic method for detecting a rolling load and a roll gap and controlling the roll gap and / or the rolling load based on the detected value and the target value of the plate thickness is used. In the plate thickness control, the increase / decrease direction of the roll gap is identified, the hysteresis correction amount is calculated based on the change amount of the roll gap after the increase / decrease direction of the roll gap is reversed, and the plate thickness control is corrected. A control method is known.

[0005]

The cause of the bending of the gambler, the nose bend, etc. and the meandering of the plate is due to the difference in the left / right gap between the rolls during rolling or the difference in the left / right plate thickness between the strips. is there. In order to prevent such bending, it is necessary to correct the gap difference to 0, but since there is no means for directly measuring the gap difference in the related art, as described above, in the conventional technique. The method of controlling by detecting the load difference between the left and right or the amount of deviation (meandering) of the plate has been performed. However, with this method, it is not possible to grasp fluctuation factors such as changes in the mill constants due to mill corrosion and wear deterioration, or changes in the mill constants due to the difference in deformation characteristics inherent in the incorporated roll chock, so the control accuracy is insufficient, and sometimes reverse It causes the trouble by controlling the direction.

On the other hand, Japanese Patent Publication No. 63-1129 discloses hysteresis for general automatic plate thickness control, which is applied to the rolling load based on the sum of the loads on the working side and the driving side of the rolling roll. Moreover, generally, if the load detection side and the roll gap adjustment side face each other with the position of the rolling mill as the center, a counterclockwise hysteresis occurs, and if they are located in the same direction, a clockwise clockwise hysteresis will occur. The same publication only describes an example of clockwise rotation. In this way, when detecting the load difference between the load cell on the working side and the driving side and recognizing bending or meandering in which the plate approaches the side with a large load, and operating the gap in the closing direction on the side with a large load, If there is a hysteresis in the detected load on the working side and the driving side, correct control cannot be performed, and there is a possibility that control will be performed by detecting underestimation or overestimation. Therefore, it is necessary to perform leveling control in consideration of the directionality of hysteresis.

[0007]

The present invention advantageously solves the above-mentioned problems of the prior art, and the gist of the present invention is that in the leveling control in hot rolling, the working side of the rolling roll is used. A leveling control method in hot rolling is characterized by adding a hysteresis correction amount to the load cell load on the drive side and correcting the rolling force on the working side and the driving side of the rolling roll.

The present invention will be described in detail below with reference to the drawings. FIG. 1 is an overall configuration diagram of plate bending control using a roll gap sensor according to the present invention. A hydraulic cylinder that applies a pressing force to the lower backup roll chocks 5 and 6 or the upper backup roll chocks 7 and 8 that support both shaft ends of the upper and lower work rolls 1, 2, and the upper and lower backup rolls 3, 4, and 4. In the hydraulic pressure-reducing rolling mill 10 which is equipped with the above-mentioned, and which is adapted to roll the rolled material 9, the amount of pressure oil that is injected into and discharged from the left and right hydraulic cylinders is controlled by the servo valve.

Further, a roll gap sensor 11 is provided for the left and right roll gaps, and the signals detected by the roll gap sensor 11 on the working side and the driving side of the rolling rolls are respectively calculated by a calculator 12 to determine the gap difference between the two. By operating the hydraulic cylinder 14 by the rolling-down control 13 that corrects the gap difference between the working side and the driving side of the rolling roll to 0, the bearing chocks 5, 6 or
The bearing chocks 7 and 8 are configured to exert a rolling force.

The output for correction is, for example, when the rolled material 9 approaches the working side W, the roll gap on the working side W is tightened to open the roll gap on the driving side D, and the rolled material is rolled. When 9 approaches the driving side D, the direction is added so that the roll gap is controlled in the opposite manner to the above.

FIG. 2 is a diagram showing a control flow for performing hysteresis compensation according to the present invention. As shown in FIG. 2, the load cell 15 on the working side (WS) and the load cell 15 on the driving side (DS) are subjected to sum load calculation and differential load calculation with hysteresis compensation, respectively, and then through the leveling control device. The leveling control is performed by adding a hysteresis compensation amount to each of the working side and the driving side by the rolling down control device. 3 and 4 are explanatory diagrams showing hysteresis characteristics.

Therefore, in more detail regarding the above-mentioned hysteresis compensation, as the measurement of this hysteresis, whether the clockwise rotation or the counterclockwise hysteresis is checked while tightening the roll opening during the suspension of the rolling and confirming the direction. The judgment is made and the amount of hysteresis is measured. As shown in FIG. 3, when the roll gap is closed, first, 0
The mill rigidity (ΔF / ΔS) _i is calculated for each measurement interval from −1, and the measurement point 8 that is the closest to the mill rigidity at the roll gap determined by the mill rigidity measurement is selected.

In the case of the roll gap opening direction as shown in FIG. 4, in the same manner as described above, in the roll gap opening direction, the mill rigidity (ΔF
/ ΔS) _i is calculated, and the measurement point 7 closest to the mill rigidity at the roll gap, which is obtained by the mill rigidity measurement, is selected. FIG. 5 is an explanatory diagram for selecting a point closest to the mill rigidity when measuring the mill rigidity. Therefore, the point closest to the mill rigidity when measuring the mill rigidity is defined by C = M × K. However, K is a value of 0.1 to 0.005 as a coefficient M: Mill rigidity at the time of measuring the mill rigidity (ton / mm) As shown in FIG. Between the upper and lower lines of C, for example, the point 7 which is the previous point that is entered three times consecutively is selected.

As described above, the hysteresis loop amount is determined not only by the positional relationship between the rolling down device and the load cell (load detector) but also by the knowledge that the loop direction is reversed on the working side and the driving side. By performing the leveling set of the roll gap of the rolling mill to be added, the variation in the bending amount with respect to the leveling amount provided on the working side and the driving side is reduced, and more accurate bending control is possible compared to the conventional technology. became.

[0015]

As described above, the loop direction of the hysteresis on the working side and the driving side of the rolling roll is determined in advance, and the hysteresis correction amount is added to the detected load on the working side and the driving side based on that direction. By performing the leveling control of the roll gap of the rolling mill, it is possible to perform extremely appropriate leveling control, improve the accuracy of bending and meandering, and secure stable stripability and shape quality. It is effective.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of plate bending control using a roll gap sensor according to the present invention,

FIG. 2 is a diagram showing a control flow for performing hysteresis compensation according to the present invention,

FIG. 3 is an explanatory diagram showing hysteresis characteristics,

FIG. 4 is an explanatory diagram showing another hysteresis characteristic,

FIG. 5 is an explanatory diagram for selecting a point closest to the mill rigidity when measuring the mill rigidity.

[Explanation of symbols]

 1, 2 Upper and lower work rolls 3, 4 Upper and lower backup rolls 5, 6 Lower backup roll chock 7, 8 Upper backup roll chock 9 Rolling material 10 Hydraulic reduction type rolling mill 11 Roll gap sensor 12 Calculation unit 13 Hydraulic reduction control 14 Hydraulic cylinder 15 Load cell

Claims (1)

[Claims] 1. In the leveling control in hot rolling, a hysteresis correction amount is added to each of the working side and driving side load cell loads of the rolling roll to correct the rolling force between the working side and driving side of the rolling roll. A method for controlling leveling in hot rolling, comprising: