JPS6245413A - Shape control method on multistage rolling mill - Google Patents

Abstract

PURPOSE:To improve a shape quality of a material to be rolled by forming one end of intermediate roll of a cluster type rolling mill to a tapered shape, etc., then controlling a vertical deflection of a work roll through a horizontal bending force of the intermediate rolls. CONSTITUTION:The first intermediate rolls 3 in set of two are contacted with the work roll 2 of the cluster type 20 high rolling mill inserting the material 1 to be rolled. Further, the second intermediate rolls 4 in sets of three of upper and lower sides and backup rolls 5 in sets of four are installed behind the intermediate rolls 3. The tapered parts 6 are provided oppositely on mutual ends of the intermediate rolls 3 and given the horizontal bending force by a hydraulic cylinder, etc. In this case, the work rolls 2 contacting with the rolls 3 are controlled their vertical deflections by the change of shapes of the tapered parts 6. In this way, the shape quality of the material 1 to be rolled is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for controlling the shape of a 12-high or 20-high cluster type multi-high rolling mill.

(Prior art) Conventionally, in a cluster-type multi-stage rolling mill with 12 or 20 stages having small-diameter work rolls, one end of an intermediate roll supporting the work roll is tapered and the intermediate roll is moved in the width direction of the material to be rolled. The shape of the rolled material is controlled by dividing the backup roll into a plurality of rolls in the width direction and adjusting the amount of displacement of each roll.

However, because the work roll has a small diameter, the shape of the work roll's deflection is complicated, and in order to obtain a rolled material with a good shape, it is necessary to optimize the shape of the intermediate roll depending on the type of the rolled material. There is a problem.

Further, the thermal crown of the work roll changes during rolling, and in the case of a small diameter work roll, this change is particularly severe, and the thermal crown rapidly increases during acceleration immediately after the start of rolling. Therefore, in order to follow this change, as mentioned above, the intermediate roll is moved (the former) and the crown adjustment is performed using the backup roll (the latter), but in the former, the movement speed is slow at low speeds, and the movement distance is There is a problem in that it is necessary to make it longer, and in the latter case, there is a problem in that there is a limit to local shape correction.

For example, a conventional general 20-high cluster type rolling mill, that is, a rolling mill having a small-diameter work roll and an intermediate roll that is movable in the width direction of the material to be rolled and has a taper near the end, is used. The results of rolling using this method are shown below.

Figure 5 shows an example of the plate shape of a rolled material when a copper alloy thin plate is rolled at a low speed. The horizontal axis shows the distance Z (am) from the center of the plate width, and the vertical axis shows the elongation rate. ε is taken, the plate width of the rolled material b = 620 mm, the entrance side plate thickness hl = 0.7 m
m, outlet plate thickness h2 = 0.5 mm, rolling speed v = 10 m/
It's a minute. As shown in the figure, in this case, the occurrence of thermal crown on the work roll is negligible and the plate shape of the rolled material is also good.

However, as shown in FIG. 6, if the rolling speed continues to be accelerated to reach v=200 m/min, the elongation in the middle becomes noticeable due to the thermal crown, and rolling becomes impossible.

To deal with this, it is necessary to move the position of the intermediate roll to an optimal value according to the thermal crown, but during low-speed rolling, it cannot be moved due to scratches between the rolls. Since it requires a fairly long distance from the ground, there is a limit to the control range under various conditions.

In addition, in Fig. 6, the rolling speed V is changed from 10 m/min to 200 m/min.
It is the same as Fig. 5 except that it is set to /min.

On the other hand, there is a known asymmetric six-high rolling mill that combines a small-diameter work roll and a large-diameter work roll in which a bending force is applied to the intermediate roll in the horizontal direction (Japanese Unexamined Patent Publication No. 52-148460). ).

However, in this rolling mill, as shown in FIGS. 7 and 8, it is necessary to apply a bending force to the intermediate roll 3a to cause bending to the center m (the central part in the sheet width direction) of the intermediate roll 3a. , the diameter of the intermediate roll 3a must be relatively large.

Therefore, the bending force also increases. Further, even if the width of the rolled material I changes, only a fixed bending deflection pattern is provided, resulting in poor controllability. This means that cluster type 6
The same applies to a plate rolling mill.

Further, the intermediate roll 3a is in contact with the backup roll over its entire length. For this reason, bending is difficult to occur due to the restraint of the outer backup roll, and a large bending force is required, which is problematic in that it shortens the life of bearings (not shown) that support both ends of the intermediate roll 3a.

(Object of the invention) The present invention has been made in view of the above-mentioned conventional problems.
The purpose is to provide a shape control method for a multi-high rolling mill that enables rolling with a small bending force, a fast response speed, and a shape with good accuracy without increasing the diameter of the intermediate roll.

(Structure of the Invention) In order to achieve the above object, the present invention includes a pair of upper and lower work rolls, and a set of two rolls is provided behind each work roll in contact with the work rolls. One end of the intermediate roll of a 12-high or 20-high cluster type rolling mill having a 12-high or 20-high intermediate roll is formed into a tapered shape or a curved outer shape with a smaller diameter than the center of the roll, and a horizontal bending force is applied to one end of the intermediate roll. was added to adjust the amount of vertical deflection of the work roll.

(Example) Figures 1 and 2 show a cluster type 20-high rolling mill to which the method according to the present invention is applied. Behind the rolls 2, two first intermediate rolls 3 are provided, one set each, in contact with the work rolls 2. Further, behind the first intermediate roll 3, there are second intermediate rolls 4, three on the top and bottom, and further behind this, four backup rolls 5 on the top and bottom are in contact with the first intermediate roll 3 or the second intermediate roll 4. It is a provision.

Among these, a tapered portion 6 is provided at the opposite ends of the upper and lower first intermediate rolls 3, and a horizontal bending force is applied to the tapered portion 6 by a hydraulic cylinder or the like (not shown). It is ready to be added. This bending force can be applied in either the direction in which the tapered portions 6 of the pair of first intermediate rolls 3 approach each other or in the direction in which they separate.
As a result, the first intermediate roll 3 in contact with the work roll 2
In particular, the shape of the tapered portion 6 is changed to adjust the deflection form of the work roll 2.

The shape control method according to the present invention applies a horizontal bending force (arrow A ), the shape of the rolled material 1 can be controlled by adjusting the deflection form of the work roll 2.

Next, the results of actual rolling by applying the method according to the present invention to the above-mentioned rolling mill will be shown.

Figure 4 shows the plate shape of the rolled material when a copper alloy thin plate is rolled under the same conditions as in Figure 6 using the above 20-high rolling mill, and the horizontal and vertical axes are also the same as in Figure 6. It is the same. That is,
This is an example in which the method according to the present invention is applied when a thermal crown similar to that shown in FIG. 6 is generated, and the position of the first intermediate roll 3 is fixed by applying a horizontal bending force to the tapered portion 6. It is shown that a good shape can be obtained even if it is left as is. Further, in this method, since the first intermediate roll 3 does not need to be moved, the response speed of the bending force is sufficiently high, and there is no restriction as in the case of the movement of the conventional intermediate roll.

In addition, although the above embodiment describes a 20-high cluster type rolling mill, the present invention is not limited to this, but can also be applied to a 12-high rolling mill of the same type. However, behind the pair of upper and lower work rolls, there is an intermediate roll that is made of two rolls and has one end formed in a tapered shape or a curved outer shape with a smaller diameter than the center of the roll, and this one end has a horizontal direction. The condition is that it can provide a bending force of .

Otherwise, due to the restraint of the backup roll behind the intermediate roll, the bending effect of the intermediate roll will be small and a large bending force will be required! This is because the applicable cone is also important in terms of the bearing life of the intermediate roll.

Furthermore, in the above embodiment, the movement of the first intermediate roll 3 in the width direction of the rolled material sheet was not considered, but the bending force and this movement, for example, the movement of the upper and lower intermediate rolls in mutually opposite directions, are considered. They may be used in appropriate combinations,
This makes it easier to handle various board width shape controls.

(Effects of the Invention) As is clear from the above description, according to the present invention, a pair of upper and lower work rolls is formed into a set, and a set is placed behind each work roll in contact with the work rolls. One end of the intermediate roll of a 12-high or 20-high cluster rolling mill is formed into a tapered shape or a curved outer shape with a smaller diameter than the center of the roll, and a horizontal direction is formed on one end of the intermediate roll. In order to adjust the vertical deflection of the work roll by applying bending force, the position of the intermediate roll is fixed (it is now possible to adjust the deflection form of the work roll even if it remains at 7). As shown in the rolling results above, it is possible to obtain a rolled material with a good shape, and the response speed of the bending force is sufficiently high, making it possible to control the shape with good response speed. Become.

Furthermore, since the tapered part is bent, there is no need for the intermediate roll to have a large diameter, and since this part does not contact the back-up roll, etc., it is possible to control the shape of small rolls by force. This has the effect of making it possible.

[Brief explanation of the drawing]

FIG. 1 shows a cluster type 20 to which the method according to the present invention is applied.
FIG. 2 is a sectional view taken along the line 1-1 in FIG. 1, FIG. 3 is a perspective view of the work roll and the first intermediate roll, and FIG. 4 is a method according to the present invention. FIG. 5 is a diagram showing the rolling results according to the method. Fig. 6 is a diagram showing the rolling results by the conventional method, Fig. 7,
FIG. 8 is a diagram showing the state of bending and deflection of the intermediate roll of a conventional rolling mill. 2... Work roll, 3... First intermediate roll, 6...
・Tapered part.

Claims (1)

[Claims] (1) A pair of upper and lower work rolls and two rolls form a set,
A 12-high or 20-high cluster type rolling mill has a set of intermediate rolls installed behind and in contact with each work roll.One end of the intermediate roll is tapered or curved with a smaller diameter than the center of the roll. The intermediate roll is formed into an external shape, and a horizontal bending force is applied to one end of this intermediate roll.
A method for controlling the shape of a multi-high rolling mill, the method comprising controlling the amount of deflection of a work roll in the vertical direction.