JPS5985314A - Device for preventing meandering motion of rolling material - Google Patents

Abstract

PURPOSE:To prevent the meandering motion of a rolling material and to obtain a product of excellent quality by obtaining the difference between the displacements of left and right holding rolls detected by detectors and changing the roll gaps at the right and left side-ends of the material. CONSTITUTION:When a rolling material 5 begins to meander to the right side of an advancing direction during rolling, the positions of left and right holding rolls 12, 13 are changed to retreat the roll 13 placed at the right side and to advance the roll 12 at the left side. These extents of movements are respectively detected by detectors 14, 15 to output signals 19 to a controller 18, and the commands which are mutually inverse in polarity are respectively transmitted to left and right rolling reduction devices 10, 11. The supply of a pressurized oil to a right-side hydraulic cylinder 7 is controlled, and a left-side hydraulic cylinder 6 is simultaneously controlled so as to increase the roll gap at the left side. Thus the roll gap at the right side of an advancing direction is decreased to prevent the meandering motion.

Description

[Detailed description of the invention] The present invention relates to a device for preventing meandering of rolled material.

In rolling operations, it is well known that, depending on the conditions during rolling, the rolled material cannot remain in the center of the rolls and moves toward the ends of the rolls as rolling progresses, as shown in Figure 1. , is called a meander.

It is also known that in order to prevent this meandering, it is important to roll the rolled material under conditions that create a convex crown.

However, in recent years, demands for improving the quality and yield of rolled materials have become stricter, and it has become necessary to reduce convex crowns as much as possible and to roll the materials so that they have a uniform thickness distribution in both the longitudinal and width directions. It is also known that such rolling tends to cause meandering of the rolled material, making stable operation difficult. In the past, once meandering occurred, it was difficult to prevent it, and in many cases, operations were stopped and the rolled material was removed.

Next, to briefly explain the meandering properties of rolled material, the first
The figure shows a situation where the rolled material a has shifted to the right side from the center of the work roll b due to l = J, etc. When the situation is as shown in Figure 1, the large rolling force is biased towards the right side of the rolling mill. As a result, the roll gap becomes uneven on the left and right sides, and the gap on the right side becomes wider than the gap on the left side. Incidentally, although the circumferential speed of roll b is uniform on the left and right sides, the gap on the right side is wider, so the volumetric flow rate of the rolled material per unit time is larger on the right side. Also, assuming that the thickness of the rolled material on the entry side is symmetrical, the material will be drawn in faster on the side with a larger volumetric flow rate. As a result,
As shown in FIG. 2, in the plane, the rolled material a is inclined with respect to the direction of movement and advances in a nodding manner, so that the rolled material a comes closer and closer to the right end of the roll. Therefore, the difference between the left and right roll gaps becomes even larger, and the rolled material a approaches the right end even more rapidly.
A phenomenon called meandering occurs.

Previously, once such a situation occurred, it was impossible to recover and operations had to be suspended.

In recent years, one of the methods for preventing meandering has been to detect meandering by detecting the change in the force applied to the left and right load cells c and d (see Figure 1) when the rolled material meanderes.
A method has been proposed in which the roll-down device is moved to narrow the roll gap on the side where the load increases.

However, this method has problems such as the change in output due to meandering and the change in output due to operating the lowering device, making the control system unstable and prone to frequency oscillations, and impairing accuracy. The drawback is that it is sufficient but not practical at all.

The present invention aims to prevent meandering through stable control, improve quality, improve yield, and stabilize rolling operations.

Hereinafter, the present invention will be explained with reference to the drawings.

Fig. 3 shows an example of the apparatus of the present invention, in which 1.2 is the upper and lower work rolls, 3 and 4 are the upper and lower backup rolls, 5 is the rolled material, and 6 and 7 are the lower backup roll chocks 8 and 9 for rolling. Hydraulic cylinder for applying pressure, 10
．． 11 is a rolling control device, 12.13 is an example of presser rolls arranged on the left and right sides of the rolled material 5 on the entry side, 14.15 is a detector for detecting the displacement (movement amount) of the presser rolls 12.13, 16. 17 is a presser spring, and 18 is a left and right pressure 1-' device which inputs a difference signal 19 when there is a difference between the detection signals from the detectors 14 and 15! II: This is a controller that sends a reverse polarity command to the 10.11 edge. Note that the roll chock, housing, etc. of this function are not shown.

Now, during rolling, the rolled material 5 is on the right side of the rolling direction due to some reason.
\If the meandering starts, the left and right presser rolls 12.13
The position of presser roll 13 on the right side is pushed by the rolled material 5 and moves backward, and the presser roll 12 on the left side moves forward by 1) 1J due to the action of the spring 6 applying a pushing force. In this way, the position of the left and right presser rolls 12 and 13 changes by 16 degrees depending on the meandering amount of the rolled material 5. This amount of movement is calculated by the detector 14.15
is detected and a signal is issued. When the difference between the detectors 14 and 15 is taken, this represents the amount of movement of the rolled material 5 to the left and right, that is, the amount of meandering. Commands of opposite polarity are sent from the controller 18, and pressure oil supply is controlled to the right hydraulic cylinder 7 to narrow the roll gap on the right side where the rolled material 5 meandered, and at the same time to widen the roll gap on the left side. The left hydraulic cylinder 6 is controlled.

This narrows the roll gap on the right side in the traveling direction and prevents meandering.

In this way, in the present invention, the left and right presser rolls 12.
13, and controls the left and right hydraulic cylinders 6 and 7 according to the difference, and changes the roll gap between the left and right ends of the rolled material to prevent meandering of the rolled material and ensure stable rolling. Can be continued.

Although the presser rolls 12 and 13 are installed on the entry side of the rolling mill, they may be installed on the exit side, or on both the entry and exit sides.

Furthermore, instead of the springs 16 and 17 to press down the presser rolls 12 and 13, an air cylinder 20, a hydraulic cylinder, or a combination of a spring and these cylinders may be used as shown in FIG. good.

In addition, although FIG. 4 shows the f row applied to a four-high rolling mill, the present invention can be applied to all types of rolling mills where meandering is a problem. It goes without saying that a software-based control circuit may be used instead of a software-based control circuit. Of course, various changes can be made without departing from the gist of the invention.

As described above, according to the present invention, (i) Since meandering can be prevented with stable control, a plate with uniform thickness distribution in the width direction can be rolled, and a product of better quality can be obtained. Can be done.

(ii) Meandering factors that tend to occur during rolling operations, such as errors in setting the left and right roll gaps, differences in properties between the left and right sides of the rolled material, and differences in thickness between the left and right sides of the rolled material at the entrance of the rolling mill. Stable operation is possible even if there is an occurrence of Therefore, operations can continue without interruption, improving productivity.

This excellent effect can be achieved.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a state in which the rolled material has come closer to one end of the roll, FIG. 2 is a plan view thereof, FIG. 3 is an example of the apparatus of the present invention, and FIG. 4 is an illustration of a device other than the present invention. It is a partial sectional view showing an example of. 1.2... Upper and lower work rolls, 5... Rolled material, 6
．． 7... Hydraulic cylinder, 10.11... Press down control device, 12.13... Presser roll, 14.15... Detector, 18... Control roller. Patent application Hitoshi Kawajima Harima Heavy Industries Co., Ltd.

Claims (1)

[Claims] 1) Presser rolls are installed at both sides of the rolled material on at least one of the entry side or the exit side of the rolling mill, and a detector is provided to detect the displacement of the six presser rolls, and the left and right displacements detected by the detector are provided. The rolling method is characterized in that it has a device for determining the difference in displacement of the presser roll, and is configured to move the left and right rolling devices according to this difference to change the roll gap between the left end and the right end of the rolled material during rolling. Meandering prevention device for materials.