JPS5942567B2 - Strip width control method using cold rolling tandem mill - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cold rolling tandem mill (hereinafter referred to as a tandem mill).

) relates to a method of also controlling the width of a cold rolled steel strip in the rolling process.

Tandem mill automatic thickness control (AGC) uses a coarse control method in which the front stand performs reduction control to coarsely control the sheet thickness, and the rear stand performs tension control to finely control the sheet thickness. .

Although this tandem mill with AGC control only controls the thickness of the copper strip, it would be extremely advantageous if this tandem mill could also control the strip width.

In other words, if the plate thickness and plate width can be controlled in the same process, the unit quantity of coils can be increased by consolidating the loft of the base material width, improving productivity and reducing yield loss during trimming. do.

Therefore, an object of the present invention is to obtain a means for simultaneously controlling strip width in a tandem mill by utilizing a part of the AGC device of the tandem mill, thereby further streamlining the process of manufacturing rolled steel strip. There is a particular thing.

In the method of the present invention, as shown in FIG.
The final stand Cn of mill C is used to control the strip width.

Originally, as shown in the figure, the normal AGC of the final stand Cn is equipped with a reduction control device 13 and a reduction adjustment device 14 into which detected values from a load cell 11 and a thickness gauge 12 are input. A tension control device 16 to which a total of 15 detected values are input is provided, and a rolling speed adjustment device 17 which is adjusted and operated in accordance with commands from the tension control device.

In the present invention, a switching circuit 2 is provided in the signal command path from the tension control device 16 to the rolling speed adjustment device 17 to control conduction of the tension control signal, and a width detection meter 3 is provided on the exit side of the final stand Cn. is installed so that the width of the steel strip after final stand rolling can be detected.

Furthermore, a width control device 4 is provided, and the detected value of the width detector 3 is inputted into this.

The width control device 4 is set in advance with a standard width dimension value, and the input width detection value is compared with the set value, and a control signal corresponding to the deviation is sent to the rolling speed adjustment device 17. Make it.

At the same time, a circuit closing signal is also issued from the width control device 4 to the switching circuit 2, and the AGC control signal input from the tension control device 16 to the rolling speed control device 17 is cut off.

Tension control is performed by measuring the tension between the rolling stands, and based on the measured value, the tension is set at the exit stand (although it may be the entry stand, generally the exit stand is used).

).

In other words, the difference in rolling speed between the two rolling mills becomes the tension between them.

When cold rolling is performed, rolling can be carried out efficiently by reducing the thickness by the rolling blades of the rolls and reducing the thickness by tension (stretching action).

Therefore, it is preferable to carry out roll reduction with a substantially constant tension applied between the stands.

Note that tension is applied at the feeding and winding sections (inlet and outlet sides of the tandem mill) of the copper strip for transportation reasons to prevent the copper strip from bunching or the like.

In particular, in the winding section, since the shape of the finished coil is affected, winding is generally performed with a constant tension.

The tension control of the winder in the method of the invention is carried out as usual, with constant tension between the final stand and the winder.

In the board width control method of the present invention, the board width is adjusted by changing the tension between the final stand and the stand in the preceding stage.

The amount of roll reduction at the final stand is to generate that tension.

In the method of the present invention, the amount of roll reduction is kept approximately constant, and the rolling speed is adjusted to actively change the tension between the pre-stage stand and the final stand.

More specifically, the width and thickness of the copper strip decreases due to tension, and the copper strip becomes slightly stretched.

Next, when the copper strip is rolled by roll reduction, the thickness of the copper strip decreases, and the thickness of the strip decreases, but metal flow occurs in the traveling direction of the strip and the width direction of the strip.

In the end, in conventional cold rolling, the thickness of the sheet decreases due to the effects of tension and roll reduction, but the width of the sheet remains almost the same.

The method of the present invention changes this balance, for example, by setting the normal rolling tension as the lower limit and applying a higher tension between the final stand and the stand before it, the base material plate is The purpose is to obtain a board width slightly narrower than the width, and adjust the amount of reduction in board width by adjusting the tension, thereby making the width of the finished board constant, and provides a specific means for controlling this.

Example In cold rolling of a 30 ton coil with a plate thickness of 0.8 myn and a plate width of 900 mm, two sizes of plate widths of 900 mm and 895 mm were rolled.

First, using a 5-stand tandem rolling mill, the rolling mills from Boi 1 to A4 stand were used for plate thickness control rolling as before, and A5
The stand is used as a width control stand, and the thickness is 0.8my.
In order to manufacture 15 tons of copper strip with size n x width 900 mm and 15 tons of size 0.8 mm thick x 895 mm wide, we first rolled 15 tons of steel strip with size 0.8 mm thick x 900 mm wide. Then, the remaining 15 tons were 0.8mm thick x 895m.
The rolling speed of 45 stands was varied (
The tension between the A4 and 55 stands was changed (change amount: 5 k!g/mi), and rolling was performed while detecting the width with a width meter (installed at the rear of the finishing rolling stand). .

As a result, the sheet width was 895 mm, which was approximately 5 mm, making it possible to roll the sheet.

In this way, by using the final stand in the coil for width control, it was possible to roll copper strips of two or more sizes, resulting in significant improvements in work efficiency and yield. .

In the present invention, plate thickness control rolling is performed in each stand before the final stand, and tenting control is performed in the final stand Cn.

The width of the strip after tentering rolling is immediately detected by the width detection needle 3 and fed back as a rolling speed command signal for the final stand, making it possible to control the width based on the set value.

As described above, according to the method of the present invention, plate thickness control and plate width control can be performed simultaneously in a cold rolling tandem mill, so the unit weight is improved by consolidating the loft of the base material width, and productivity is increased. This reduces the unit power consumption.

In addition, the efficiency of trimming improves the yield of finished products.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the overall configuration of the width control method according to the present invention. 2 switching circuit, 3: width detection needle, 4: width control device, 11: load cell, 12: thickness gauge, 13: reduction control device, 14: reduction adjustment device, 15: tension meter, 16: tension control device, 17: Rolling speed adjustment device, S: Steel plate.

Claims (1)

[Claims] 1. A width detector for the rolled steel strip is installed on the exit side of the final stand of the cold rolling process by a tandem mill to detect the strip width, and a reference value for the strip width dimension is set in advance in the width control device. The standard value is compared with the detection signal from the width detector to determine the deviation, firstly, the final stand portion of the command line of the normal rolling tension control device is shut off, and the deviation is used instead for the final stand rolling. It consists of commanding a speed regulator,
A strip width control method using a cold rolling tandem mill, characterized in that stands other than the last stand among the plurality of rolling stands are used for strip thickness adjustment, and the last stand is used for strip width adjustment.