JPS6363512A - Strip width control method in cold rolling - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for controlling the width of a rolled sheet in a rolling process using a cold rolling mill.

(Prior Art) If the width of the sheet can be controlled during cold rolling, the yield can be improved and the product steel types can be expanded, so the effect is extremely large.

Measures taken to deal with the current sheet width are as follows: 1. For products that require strict sheet width, trim work is performed after cold rolling to make the sheet width uniform.

■Products other than those listed above are either trimmed before cold rolling, taking into account width expansion and convergence after rolling, or omit trimming and instead add a margin.

As described above, the current situation is that efficient manufacturing has not been achieved regarding the board width.

Methods for controlling strip width in cold rolling that have already been announced include, for example, Japanese Patent Publication No. 59-228.
There is a method of using tension as the control amount, as disclosed in Japanese Patent Publication No. 03 and Japanese Patent Publication No. 59-42567.

It is known that such a rolling method is certainly effective in controlling the sheet width.

(Problem to be solved by the invention) However, the operating factor of tension is the thickness control in the rolling direction @
(AGC), it was desired to use operating factors different from plate thickness control as much as possible.

(Means for Solving the Problems) The present invention meets these demands and is characterized by using the amount of movement of a work roll having a crown in the roll axis direction as a control factor for plate thickness. .

That is, the strip width control method of the present invention detects the strip width at the entry side of the rolling mill in a rolling mill in which a pair of upper and lower work rolls have roll crowns and the work rolls are movable in the roll axis direction. Determine the deviation from the preset board width dimension, calculate the amount of movement of the work roll according to this deviation, and instruct the work roll movement adjustment device to adjust the position of the work roll to adjust the board width. .

(Function) In plate rolling, sufficient tensile stress is generated to plastically deform the part near the edge of the plate before the roll bite entrance, and the width of the plate changes in response to this tensile stress before the roll bite entrance. It changes with On the other hand, when the work roll having the above profile is moved in the roll axis direction, the axial deflection of the work roll changes. Therefore, if the amount of movement of the work roll in the roll axis direction is adjusted according to the strip width detected at the entrance side of the rolling mill, the stress distribution in the strip width direction will change and the amount of width reduction of the strip, that is, the strip width. can be adjusted to obtain the required board width.

(Examples) Hereinafter, the present invention will be specifically explained while showing examples.

First, the basic principle of the present invention will be explained. The work roll used in the experiment had a roll diameter of Φ1651 and a roll body length of 400 mm, and the starting point was 25 mm from the center of the roll.
mH crown on one side and flat on the other side (upper roll). The lower roll is machined point-symmetrically with respect to the upper roll and assembled into the rolling mill. Rolled material is 250 layers wide 1
The coil had a thickness of 2.71 mm and was made of ordinary steel (low carbon steel).

Figure 1 shows the tension distribution in the width direction of the plate in the distance from the roll bit entrance to the unrolled part (reduction ratio 30, rear tension 5 kg/mm2, front tension 10 kg/m1d2).
. From FIG. 1, it can be seen that sufficient tensile stress is generated to plastically deform the material before the roll bite entrance. Figure 2 shows the change in board width at that time.

From Figure 2, it was discovered that the plate width had already changed before the roll bite entrance. Furthermore, when the work roll is moved, the stress distribution shown in Figure 1 changes, and as shown in Figure 2, the amount of width contraction of the board can be adjusted. Understood. Furthermore, as shown in Figure 2, this phenomenon does not occur when rolling with normal flat rolls, and a slight widening within the roll bite was confirmed as conventionally said. . The present invention is characterized by associating such a phenomenon with predeformation and actively using this predeformation.

Next, one embodiment of the present invention will be described. An example of the configuration of the device based on FIG. 3 is shown. In FIG. 3, 2 and 2 are work rolls having a crown as described above. 3 is a rolled material with a thickness of 2.7cm and a width of 250m, and the plate width fluctuation of plus or minus 11 shoulders is marked with a SIN curve at a pitch of 10cm. Reference numeral 4 denotes a work roll movement adjustment device, which calculates the amount of work roll movement and sends the signal from the work roll movement amount calculator 6, which receives the signal and sends the signal to the work roll movement adjustment device at the appropriate timing. An instruction device 5 (described in detail later) receives an instruction signal for the amount of work roll movement and controls the position of the work roll. Reference numeral 7 denotes a plate width detector, which is installed at a distance from the first roll bite inlet.In this embodiment, a contact type plate width detector is used, and L=80cm. The signal from this board width detector is sent to a board width deviation calculator shown at 9. The board width deviation calculator also receives the signal from the standard board width setter shown in 8 as input, calculates the deviation from the signal from the board width detector mentioned above, and outputs the result to the work roll shown in 6. It serves to send to the movement amount calculator. In this example, the reference plate width is 248.5
■It is set to Otori. Now, the work roll movement amount calculating unit 6 which receives the deviation signal calculates the movement amount of the plow work roll based on the deviation signal.
I will explain how to find it. First, conduct an experiment in advance to determine the relationship between the amount of work roll movement and the amount of sheet shrinkage.
The relationship is approximated by an approximate expression. In this embodiment, approximation is performed using a quadratic equation. This approximate formula changes when the rolling reduction, strip width, tension, etc. differ, so it is necessary to have a data bank so that the coefficients in the approximate formula can be selected depending on the rolling conditions.
(not shown). The amount of work roll movement is calculated using such a method, and the result is sent to the work roll movement adjustment device. At this time, it is necessary to perform tracking to eliminate the influence of the distance between the sheet width detector and the work roll entrance. For this purpose, in this embodiment, the plate speed is detected at any time using a plate speed detector (contact type) shown in 10, the transfer time of the plate from the plate width detector to the roll bit inlet is calculated, and the work roll The delay timing indicating device shown in 5 sends the above-mentioned work roll position to the work roll movement adjusting device taking into consideration the response time of the movement adjusting device. In response to the signal from the delay timing instruction device 5, the work roll position is controlled by the work roll movement adjustment device 4. As a result of experiments conducted using such a board width control device, it was possible to control the board width with an accuracy within +0.2 m layer relative to the target board width. Regarding the plate thickness in the rolling direction, sufficient plate thickness accuracy (center plate thickness) was obtained since it did not affect the total tension of the present invention.

(Effects of the Invention) According to the present invention, trim work for adjusting the board width is not required, and yield and work efficiency can be improved. Further, since tension is not used as the manipulated variable for control, there is no mutual interference between plate thickness control and plate width control.

Note that the present invention is particularly effective when rolling a copper strip without trimming in the pre-rolling process.

[Brief explanation of drawings]

FIG. 1 is a stress distribution diagram in the sheet width direction explaining the present invention in detail, FIG. 2 is a diagram showing a pre-deformation phenomenon showing the principle of the present invention, and FIG. 3 is an embodiment of the present invention.
This is a simple overview of the board width control method.

Claims (1)

[Claims] In a rolling mill in which a pair of upper and lower work rolls have roll crowns and the work rolls are movable in the roll axis direction, the strip width is detected at the entrance side of the rolling mill, and the deviation from the preset strip width dimension is determined. A plate width in cold rolling characterized in that the plate width is adjusted by calculating the movement amount of the work roll according to this deviation and instructing a work roll movement adjustment device to adjust the position of the work roll. Control method.