JPH03408A - Method for preventing sheet thickness from varying by roll eccentricity - Google Patents

Abstract

PURPOSE:To easily and at low cost prevent the sheet thickness from varying due to eccentricity of rolls by idling upper and lower backup rolls very small in a difference between outer diameters to each other and starting rolling in a phase minimizing load variation by the eccentricity of the detected rolls. CONSTITUTION:The upper and lower work rolls provided with backup rolls of a rolling mill are driven synchronously to perform rolling. In this rolling mill, the difference between the outer diameters of the upper and lower backup rolls is set in advance within a required fine range. Further, they are idled relatively and the relative phase in the rotational direction is changed. In that case, a kiss-roll operation is performed in each phase state and a relative phase minimizing the load variation due to roll eccentricity is detected and stored. Before the actual rolling is started, these upper and lower backup rolls are idled relatively and after they are paired at a position aiming at this detected relative phase they start rolling. Consequently, the variation of sheet thickness by eccentricity of the rolls is retained in a fine range, no roll slip is followed and high-quality rolling can be performed stably for a long period of time.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for preventing plate thickness variation due to roll eccentricity in a rolling mill, and in particular, it can be realized at low cost by extremely simple means, and it can reduce the length of the plate due to roll eccentricity. The present invention relates to a method for preventing sheet thickness variation due to roll eccentricity, which is suitable for irreversible rolling and high-speed rolling of relatively long rolled materials.

[Conventional technology]

Conventionally, as a method for preventing changes in plate thickness due to roll eccentricity in rolled materials, for example, the change in roll gap due to roll eccentricity is calculated, and the reduction amount is changed by operating a rolling device to cancel the change in thickness. (Japanese Unexamined Patent Publication No. 64-87010), or the positional relationship between the upper and lower backup rolls in which the roll load fluctuation amount shows the minimum value when the kiss roll is driven is detected and stored in advance, and the controlling the rotational speed of the work roll to equalize the stored positional relationship between the upper and lower backup rolls;
(Japanese Patent Publication No. 62-19241) and the like have been provided.

[Problem to be solved by the invention]

However, in the former method of the above conventional method,
In reality, rolling pressure and plate thickness signals are affected by various factors other than back-up roll eccentricity, such as the rolling blade, the hardness of the rolled material, and the rolling speed, so it is difficult to determine the roll gap change due to roll eccentricity. A satisfactory correction effect cannot be expected, and especially during high-speed rolling, there is a delay in the follow-up of the hydraulic rolling device, making accurate correction and control impossible.

In addition, in the latter method, which controls the rotation of the work roll during operation, the work roll is used to directly apply liquid to the material to be rolled, so there is some slippage between the work roll and the material to be rolled. In addition to the risk of scratches on the surface of the rolled material and work roll, there is also the inconvenience that it can only be applied to rolling mills with an independent drive system in which the upper and lower work rolls are each driven by an independent drive source. .

Furthermore, since both control the rolling down device or the drive system of the rolls during operation, each device to be controlled is required to have high-speed and high-precision responsiveness. The disadvantages are that it is complicated and extremely expensive, and that it is difficult to adjust and is prone to failure.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method that can effectively suppress plate thickness variations due to roll eccentricity using extremely simple means.

[Means to solve the problem]

The method for preventing plate thickness variation due to roll eccentricity according to the present invention is based on a rolling mill in which upper and lower work rolls are driven synchronously, and in advance, one of the upper and lower backup rolls is adjusted so that the outer diameter difference between the two backup rolls is within a required minute range. In addition, the kiss roll operation is performed in each phase state while changing the relative phase of the rotational direction of both backup rollers by idling at least one of the upper and lower backup rolls with respect to the other. The relative phase of the upper and lower backup rolls that minimizes the load fluctuation due to roll eccentricity is detected and memorized, and the detection of both backup rolls is performed by idling at least one of the upper and lower backup rolls relative to the other before the start of rolling. This method is characterized in that the relative phases thus obtained are combined at a targeted position, and then rolling is started.

[Effect]

By making the diameter difference between the upper and lower backup rolls minute, the waviness of plate thickness fluctuation caused by the eccentricity of the upper and lower backup rolls can be made to have a long period (long wavelength). On the other hand, even if the upper and lower backup rolls have eccentricity, the variation in plate thickness becomes small since they are in a phase that cancels out each other's eccentricity.

Therefore, by satisfying the above two conditions simultaneously, there will be almost no plate thickness variation due to roll eccentricity (
Long length rolling becomes possible.

The optimal combination position (optimal relative phase) of the upper and lower backup rolls can be found from load fluctuations due to kiss roll operation.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

1 and 2 schematically show a rolling mill according to the present invention, where 1a is an upper roll, 1b is a lower work roll, and 2a is an upper buffer.

Brol, 2b is a lower back up roll.

In this case, this rolling mill is of a vertically synchronous drive type in which the upper work roll 1a and the lower work roll 1b are driven by a common drive source (such as a motor) 3. Below the lower back-up roll 2b is a hydraulic reduction cylinder 4 equipped with a position detector in the direction of reduction, and above the upper back-up roll 2a is a rolling load detector (load cell) 5.
is provided. Upper and lower work rolls 1a, 1b
The upper backup roll 2a and the upper work roll 1a can be separated by a work roll balance cylinder 6 interposed between them, and the upper backup roll 2a and the upper work roll 1a can be separated by an upper backup roll balance cylinder 7 interposed between them. .

Further, the upper and lower backup rolls 2 a, 2 b are set so that the difference in outer diameter (pair difference) between the rolls is extremely small. For example, the upper and lower backup rolls 2 a, 2 b The error in the outer diameter of is o, o
It is set to be within os%.

Note that the pairwise difference between the work rolls la and 1b is originally set within an extremely small range.

FIG. 3 shows an example of the configuration of a control mechanism and a control circuit that are attached to the rolling mill to realize the present invention.

Reference numeral 8 in the figure indicates the position of the upper backup roll 2a in the rotational direction, that is, the upper backup roll 2 rotating around the axis.
A rotational position detector for the upper backup roll detects how many times a is rotated from the reference position (phase from the reference position), and reference numeral 9 similarly detects the position of the lower backup roll 2b in the rotational direction. This is a rotational position detector for the lower back up roll. These upper backup roll rotational position detectors8. The lower backup roll rotational position detector 9 is connected to an initial relative phase storage device 10 that stores the initial values of the rotational positions of the upper and lower backup rolls 2a, 2b based on the signals from both rotational position detectors 8.9. has been done. Further, this initial relative phase storage device 10 is connected to an addition circuit 12 that performs calculations based on signals from the initial relative phase storage device 10 and the relative phase change command device 11, and the addition circuit 12 is further connected to a determination circuit 13. The determination circuit 13 is connected to a drive source control device 14.

By connecting the control device 14 to the drive source 3, the drive source 3 is controlled based on the drive source control device 14. Further, either the upper backup roll rotational position detector 8 or the lower backup roll rotational position detector 9 (in the illustrated example, the lower backup roll rotational position detector 9) is also connected to the determination circuit 13. are connected, and the determination circuit 13 determines that -
The configuration is such that a determination result based on a signal from one rotational position detector 9 and a signal from an addition circuit 12 is sent to a control device 14. Further, the signal from the rolling load detector 5 is connected via a signal averaging processing device 15 to a storage table 16 that stores load fluctuation values corresponding to the relative phases of the upper and lower backup rolls 2 a and 2 b.

Next, a method for preventing sheet thickness variation due to roll eccentricity according to the present invention will be explained based on the above configuration.

First, in order to facilitate understanding of the present invention, FIG. 4 shows a flowchart of a rough procedure for carrying out the present invention.

That is, after setting the upper and lower backup rolls 2 a and 2 b in SP (step)-A so that the dimensional difference (pair difference) in their outer diameters is within a required minute range, S
At P-B, find the phase of the upper and lower backup rolls 2a, 2b in which the load fluctuation during rolling on the kiss roll read by the rolling load detector 5 is minimized,
Rolling is carried out at 5pc in accordance with the phase.

FIG. 5 details the contents of SP-'B in FIG. 4. That is, in order to detect the phase of the upper and lower backup rolls 2a, 2b where the load fluctuation is minimum, the following procedure may be used.

(SP-BIO> First, the load fluctuation under the kiss-roll state at the current (arbitrary) phase is measured.

For this purpose, the upper backup roll rotation position detector 8. The lower backup roll rotation position detector 9 detects the current phases of the upper backup roll 2a and the lower backup roll 2b in the rotation direction, and based on the detected values, the upper and lower backup rolls 2a, 2b are detected. The relative phase, that is, the relative positional relationship is calculated and stored in the initial relative phase storage device 10.

Next, by operating the hydraulic reduction cylinder 4, all of the upper and lower work rolls 1a, 1b and the upper and lower backup rolls 2a, 2b are brought into contact with each other (kiss roll state) as shown in FIG. Crimp. Thereafter, by driving the drive source 3, the upper and lower work rolls la, lb and the upper and lower backup rolls 2a, 2
b is rotated, and the rolling load detector 5 measures the load fluctuation. The measured load fluctuation values are stored in the storage table 16. Note that, as shown in the figure, the rolling load variation amount corresponding to the relative phase of the upper and lower backup rolls 2 a and 2 b is recorded in this memory table 16 .

<5P-820> Next, cut the edges between the upper and lower backup rolls 2a and 2b. To do this, the hydraulic pressure reduction cylinder 4 is retracted, the upper backup roll cylinder 7 is extended, and the sixth
It is sufficient to set the state as shown in Fig. (b).

<5P-830> When the above state is reached, the lower back up roll 2 is activated by operating the drive source 3 as shown in FIG. 6(c).
Rotate the upper and lower backup rolls 2a and 2b.
change the relative phase between

The phase change here is performed by rotating the lower back-up roll 2b by a certain angle divided into equal parts (for example, π/4 divided into eight equal parts) in the circumferential direction.

<5P-B2O> After changing the phase, each roll is brought into a kiss roll state again as shown in FIG. 6(d).

<5P-850> By operating the drive source 3, the load fluctuation at the position whose phase has been newly changed is measured.

<5p-860> If the operation of the above SP-850 is less than the specified number of times, that is, 2π of one revolution of the lower back up roll 2b, repeat the operations of the above SP-820 to SP7 B 50 until the specified number of times are performed. If so, proceed to 5P-870.

<5P-870) The upper and lower backup rolls 2a minimize the load fluctuation measured by the rolling load detector 5 according to the following procedure.

Find the relative phase of 2b.

For example, move the lower pull-up roll 2b to π/ as shown in FIG.
4 Divide into 8 equal parts, and each point is R,, R,, R,,...
shall be. Now, here is the maximum positive eccentricity point Q of the actual roll diameter of this lower back up roll 2b.

It is assumed that there exists between point R3 and point R6. Then, according to the steps 5P-840 and 5P-B5O, the measurement results of load fluctuations are stored in the memory table 16 as shown in FIG.
Record (memorize).

FIG. 8 shows that the amount of load fluctuation changes (causing "undulation") due to the difference in relative phase between the upper and lower backup rolls 2a and 2b. Here, the graph of load fluctuation shown in the same figure and Figures 9(a) to 9(a)
Upper and lower backup rolls 2a and 2b shown in (g)
The relative positional relationship between them is shown in FIG. Note that the symbols are representatively attached only to the figure (a). In Figure 9,
The black dots attached to the upper and lower backup rolls 2a and 2b respectively indicate the respective backup rolls 2a and 2b.
2b shows the maximum eccentricity point on the plus side. That is, if there is a pair difference between the upper and lower backup rolls 2a and 2b, both backup rolls 2a,
2b, a phase difference occurs as shown in FIG. 9 with rotation. In other words, the relationship between the upper and lower backup rolls 2a and 2b, which had the relative positional relationship shown in FIG. 9(a), gradually shifts as shown in FIG. 9(b)→(C)→(d)→... That's why I'm going.

The amplitude of the load fluctuation is determined by the state shown in FIG.
, 5π, ...), the maximum is reached, and the figure (b
) or state (f), that is, both backup roles 2
Maximum eccentric points Q, , Q at a, 2 b, respectively
becomes minimum when the phase difference of , becomes 0 (2π, 4π, . . . ).

Therefore, one of the buffer knob rolls (lower back up roll 2b in the embodiment) is equally divided as shown in FIG. 7, and a load corresponding to the relative phase between the upper back up roll 2a and the lower back up roll 2b is applied. By recording the fluctuation state, for example, as shown in FIG.
This means that we can find the phase of .

In this case, the maximum eccentric point Q of the upper backup roll 2a
1, point R of lower back up roll 2b? ＋R
, Upper and lower backup rolls 2 so that the sections in between are facing each other.
If the phases of a and 2 b are aligned and rolling is performed in that state, the amount of load variation will be minimized.

As described above, when the optimal relative phase between the upper backup roll 2a and the lower backup roll 2b is found, the relative rotational position of the upper backup roll 2a and the lower backup roll 2b at that time is It is detected by the rotational position detector 8 for backup roll and the rotational position detector 9 for lower backup roll, and is stored in the initial relative phase storage device 10.

This completes 5P-B in Figure 4, and then 5P-B in Figure 4 is completed.
Move to p-c.

sp-c is a step in which rolling is carried out by setting the relative phase of the upper and lower backup rolls 2a, 2b to the optimum combination phase detected by SP-B, and the details thereof are explained in FIG. 10.

<5p-cto> The upper and lower backup rolls 2a are formed by the above SP-B.

2b is set to the optimum phase condition, FIG.
As shown in a), the upper and lower backup rolls 2a and 2b are brought into contact with the upper and lower work rolls 1a and 1b, respectively.

<5P-020> Once the upper and lower backup rolls 2a and 2b are set to the optimum phase as described above, rolling is started (Fig. 11<b)).

<5P-C30> When performing the next rolling, the process moves to SP-C40.

<5P-C40> This SP-C40 and the following SP-C50 are the previous SP
-Upper and lower backup roll 2a generated by C30,
This is a process of correcting the relative phase shift between the two rolls 2b, and is carried out during idle time when rolling is not performed.

Here, first, as shown in FIG. 11(c), the edges between the upper and lower backup rolls 2a and 2b are cut. This operation is the same as for SP-820.

<5P-C50> Next, as shown in FIG. 11(d), the lower backup roll 2b is rotated (idling) by operating the motor 3, whereby the upper and lower backup rolls 2a
, 2b to the initial state, that is, the SP-B
70 to reach the optimum state. Since the relative phase that provides the optimal combination of the upper and lower backup rolls 2a and 2b has already been detected and stored in the initial relative phase storage device 10, this operation is performed when a deviation has occurred from the stored optimal phase at the present time. In consideration of the phase, the relative phase change command device 11 automatically executes the command.

As a result, the upper and lower backup rolls 2 a and 2 b are combined and rotated again at the initial optimal relative phase, that is, the relative phase where the amount of load fluctuation due to roll eccentricity is the smallest.Moreover, both backup rolls 2 a
, 2b has an extremely small bare difference, so it is possible to perform the most excellent rolling with little variation in plate thickness over a long period of time (long length).

Now, to explain the above example by applying actual numerical values, the actual diameter D1 of the upper backup roll 2a is φ1300 mm, and the actual diameter of the lower backup roll 2b is φ1300.03 (bare difference: 0.03+
0.0023%).

Due to the rotation of both backup rolls 2a and 2b, a rotational difference (phase difference) is generated between the upper backup roll 2a and the lower backup roll 2b. Here, both backup roles 2 a, 2
The rotation speed N of the upper backup roll 2a for starting rotation from a certain phase relationship and returning to the same phase relationship is: 43333 [rotations] Therefore, the undulation of load fluctuation, that is, 1 of the undulation of plate thickness fluctuation. The wavelength is the length of 43333 rotations of the upper backup roll 2a.

At this time, the rolling extension length Q is: Q = D, π×N -177000 [m] Therefore, the length (wavelength) of one period of waviness is approximately 1
This means 77000111.

By the way, the plate thickness of the material to be rolled is 0.3 mm, and the outer diameter is φ1.
When attempting to manufacture a 900 mm fill, the total length of the coil is approximately 850 On+, which is less than 5% of the length of one period of waviness (see Figure 12).

That is, in this way, the upper and lower backup rolls 2 a
, 2b is set to a small value, and rolling is performed by combining both backup rolls 2a and 2b so that their relative phases cancel out their eccentricities, when rolling one coil, Not only does the "undulation" due to plate thickness variation not even one wavelength appear over the entire length of one coil, but the plate thickness variation due to the eccentric center of gravity of the roll can be made so small that it can be ignored. And for each l coil,
By setting the relative phases of the upper and lower backup rolls 2 a and 2 b to the initial setting positions, rolling can be performed with extremely small fluctuations in plate thickness due to roll eccentricity at all times.

Moreover, the means is the upper and lower backup rolls 2, a2
Cut the edge between b and upper and lower backup rolls 2 a, 2
This is extremely easy since it only requires a slight rotation of one of the parts b. Furthermore, since there is no need for complicated devices and mechanisms for controlling the rolling device and the drive device during operation, reliable effects can be achieved at low cost.

In the present invention, as described above, it is essential that the error in the outer diameters of the upper and lower backup rolls 2a and 2b, that is, the difference between the pairs, be minimized. Ideally, this bare difference would not exist at all, but in terms of both effectiveness and processing cost, the range of pair difference is within o, oos% (for example, approximately 0.1 mm for a roll outer diameter of φ1300n+m). It is desirable to do so.

If it is within this range, sufficient effects will be exhibited for the normal rolling length, and the dimension setting (processing) of the backup roll will be technically extremely easy.

Furthermore, since the present invention does not require the rolling device to be controlled during rolling operation, it can be applied to high-speed rolling, where conventionally it has been difficult to follow the rolling device, without any problems. Moreover, since no slip occurs between the material to be rolled and the work roll, it can be applied to a rolling mill with a vertical synchronous drive system, and there is no risk of impairing product quality or damaging the work roll. Furthermore, the present invention can be applied even to a rolling mill with an upper and lower independent drive system by operating the upper and lower work rolls in complete synchronization.

In addition, in the embodiment, the upper and lower backup rolls 2
The explanation has been made assuming that rolling starts from the optimum phase position of a, ``; 2 b, but in reality, it is desirable to set the optimum phase position to be in the middle of the total rolling extension. This is because fluctuations in plate thickness can be suppressed to a smaller range.

If the compression extension is determined in advance, the upper and lower backup rolls 2a, 2b can be easily set in this manner by changing the setting values of the relative phase change command device 11 and the like. Therefore, in the present invention, the initial positional relationship of the upper and lower backup rolls 2a+2b such that the optimal phase relationship is located in the middle of the total pressure extension can also be referred to as the optimal initial position.

In addition, in the example, the combined load measurement points of the lower backup roll 2b were set at 8 locations (divided into 8 by π/4);
Of course, it is also possible to make the division even finer and increase the number of measurement points. In that case, the upper and lower backup rolls 2 a
, 2b can be determined more accurately.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to reliably roll a long length of steel with extremely simple means, with variations in plate thickness due to roll eccentricity kept within a very small range. Moreover, since there is no need to control the hydraulic pressure reduction device or drive system during operation, the complicated
It does not require expensive control equipment, can be easily applied to high-speed rolling, and can reliably prevent plate thickness fluctuations due to roll eccentricity, and does not cause each roll to slip during operation. Therefore, the quality of the product can be improved in terms of heat, the life of the roll can be ensured, and various other excellent effects can be achieved.

[Brief explanation of drawings]

1 and 2 schematically show a rolling mill to which the present invention is applied; FIG. 1 is a side view thereof, FIG. 2 is a front view thereof, and FIG. 3 is a control of the rolling mill according to the present invention. FIG. 4 is a flowchart showing an outline of the procedure of the method for preventing sheet thickness variation due to roll eccentricity according to the present invention; FIG. 5 is a flowchart detailing a part of the contents of FIG. 4; FIG. a)～
(d) shows the states of the upper and lower backup rolls corresponding to the blocks of the flowchart shown in Figure 5, and is a side view schematically showing each roll, and Figure 7 shows the state of the lower backup roll. Fig. 8 is a side view schematically showing each roll to explain the dividing points, and Fig. 8 is a diagram showing the state of load fluctuation due to the phase difference between the upper and lower backup rolls.
Figures 9 (a) to (g) show the combined state of the upper and lower backup rolls corresponding to Figure 8, and are side views schematically showing the rolls, and Figure 1O shows the contents of Figure 4. Flowchart showing some details, Figures 11(a) to (d)
) represents the state of the upper and lower backup rolls in correspondence with the blocks in the flowchart shown in Figure 10.
FIG. 12 is a side view schematically showing each hole, and FIG. 12 is a diagram for explaining the present invention in detail and showing a state of plate thickness variation in the present invention. la...Upper work roll, Ib...Lower work roll, 2a...Upper backup roll, 2b...
・Lower backlash prowl. Deyorito Sky Aluminum Co., Ltd. Figure 1 Figure 2

Claims (1)

[Claims] In a rolling mill in which upper and lower work rolls are driven synchronously, the outer diameters of the upper and lower backup rolls are set in advance so that the difference in outer diameter of both the backup rolls is within a required minute range, and the The relative phase of the upper and lower backup rolls minimizes load fluctuations due to roll eccentricity by performing kiss roll operation in each phase state while changing the relative phase in the rotational direction of both backup rolls by idling at least one of the rolls relative to the other. is detected and memorized, and before the start of rolling, at least one of the upper and lower backup rolls is rotated idly relative to the other to combine both backup rolls at a position that targets the detected relative phase, and then the subsequent rolling is performed. A method for preventing sheet thickness fluctuation due to roll eccentricity, characterized by: