JPH04100606A - Hot rolling method using cluster type rolling mill - Google Patents

Abstract

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

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method of hot rolling using a cluster rolling mill, and in particular to a method of hot rolling a sheet by displacing the axis of a work roll in the horizontal or vertical direction. The present invention relates to a method for obtaining a rolled plate with little change in thickness in the width direction.

(Prior Art) Conventionally, in strip rolling, there is a problem of so-called edge drop, in which the thickness of the strip at the ends in the width direction of the strip decreases rapidly compared to the thickness of the strip at the center. The position where this edge drop occurs is several LOW from the edge of the board width, and has a severe good shape (
In response to the request for a rectangular cross section, this part had to be cut off, reducing production yield.

It is a well-known fact that edge drops are caused by flattening deformation occurring at the contact portion of the work roll with the rolled material and axial deflection of the roll system due to the rolling reaction force between the rolled material and the work roll. In order to improve this, a method has been used in which a pending force is applied to the work roll to deflect it, but this method has a limited ability to control the shape. In particular, the backup roll (hereinafter referred to as BUR) over the entire length of the work roll body
For this reason, as in a six-layer rolling mill, the intermediate roll is shifted in the axial direction, and the movement of this intermediate roll is combined with the pending force of the work roll to improve the axial deflection of the work roll. In this method, since the roll bending effect acts on the entire length of the roll, there is a problem that if focus is placed on improving edge drop, the rolled material will undergo mid-elongation.

The edge drop phenomenon not only improves the corrective function due to the roll pending force described above, but also reduces the deformation of the work roll due to rolling reaction force by reducing the rolling load on the work roll.

JP-A-56-62804 describes a cold rolling method for the above-mentioned rolling load, but a cluster mill is placed upstream of the final stand of a tandem rolling mill to enable high-reduction rolling. It is also disclosed that edge drop can be reduced along with

The technology disclosed in the above-mentioned publication is related to cold rolling, but in hot rolling, there is a problem of changes in the roll crown due to thermal expansion and friction of the roll, and it is necessary to exhibit a roll bending function that is not constrained by BUR. . JP-A-58-82604 discloses that a work roll is deflected by shifting it from the axis of the BUR toward the rolling line, and the work roll is held down by an auxiliary roll that is movable in the longitudinal direction, and the work roll is moved in the horizontal direction. It is disclosed that the above-mentioned problem can be solved and the shape can be controlled by controlling the displacement (deflection) of. However, according to this method, since the auxiliary roll is provided to press the work roll from only one side, there is no restraint on the opposite side, which may make rolling difficult if vibration occurs. There is.

(Problems to be Solved by the Invention) The present invention improves the problems of the conventional technology as described above, and involves hot rolling using a cluster type rolling mill. The rolls enable high-reduction rolling, and by bending the work rolls so that the roll vector is inward,
The object of the present invention is to provide a hot rolling method capable of obtaining a hot rolled sheet without edge drops.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention provides a backup roll ( BUR)
When performing hot rolling using a cluster type rolling mill with
Set so that R and BUR on the exit side are in opposite directions,
The gist of this invention is a hot rolling method using a cluster-type rolling mill, which is characterized in that a pressurized material is rolled with the axial direction of the work rolls bent in a substantially horizontal plane.

The BUR
It is also one of the gist of the present invention to adjust the amount of displacement of each of the above-mentioned planes, and to apply a pending force to the above-mentioned plane so that it becomes intermediate in the vertical direction along with the deflection.

The present invention will be explained in detail below.

The cluster type mill of the present invention, for example, as shown in FIG.
This is a six-stage mill, which is the upper mill, and below it is composed of two-stage rolls: a large-diameter work roll 8 and a reinforcing roll (BUR) 9. The present invention is not limited to this, but also includes a case in which cluster mills made of the above-mentioned multi-stage rolls are disposed above and below. Further, a rolling mill having such a configuration may be incorporated into a tandem rolling mill, or may be used independently. In tandem rolling mills that normally produce hot strips, at least one of the
It is preferable to incorporate it into the last stage or two or three rear stages including it. In cluster type mill,
In the side BUR, eccentric bushings of a plurality of divided small rolls are fixed to a shaft, and by rotating this shaft, suppression is performed according to the position of the eccentric bushings. However, in the present invention, the divided small rolls are provided so as to be rotatable independently. That is, as illustrated in FIG. 2, the sleeve 11 of the divided small roll 10 is rotatably attached to an eccentric bush 13 via a roll bearing 12, and the bush 13 is rotatably attached to the BUR roll shaft 14. Fixed. A support arm 15 supports the eccentric bush 13, and is connected to a movable shaft 16 at its upper part. Movable axis 16
meshes with a gear on a rotating shaft 17 connected to a power source on the side. A rack gear 18 is provided to move the support arm 15, rotate the eccentric bushing 13, and position the divided rolls.

Since the present invention has a BUR having the above structure, the work roll 2 is bent (deflected) through the intermediate rolls 3 and 4 by positioning (displacement) of the divided small rolls. FIG. 3 schematically shows the state of roll deflection of the cluster mill 1 excluding the center reinforcing roll in a side view. That is, in the same figure (a), the solid line indicates the normal roll arrangement, and such a roll arrangement is changed by displacing the small rolls split on both sides of the entry side BUR 5 downward in the direction of the arrow (d), By displacing the small rolls split on both sides of the exit BUR 6 upward, each roll is placed in the position shown by the dotted line. The deflection of the small-diameter work roll 2 when each of the BURs 5 and 6 is displaced to the dotted line position is as shown in FIG. 4(b).

Such a state will be further explained in detail with reference to FIG. Fig. 4 is a developed view of the cluster mill, in which each of the divided small rolls 101 to 105 of BUR5 on the entry side E of the material to be rolled is concave in the center toward the rolling direction (arrow 19). Position the eccentric bushing 13 so that
At the contact portion with the intermediate roll 3, the outer roll 101.
105 is set so that the amount of displacement is large and becomes minimum at the intermediate portion 103. Further, in the exit side O BUR 6, the displacement of each divided small roll is made in the opposite direction to the input side BUR 5 at the contact portion with the intermediate roll 4. That is, outer roll 1
01.105 has a small amount of displacement, and the center roll 103 has the least amount of displacement. BUR5 set like this,
From 6 onwards, the work roll is pressed and deflected via intermediate rolls 3 and 4. That is, the input side BUR applies a pressing force to the work roll 2 from the axial end of the work roll 2, and the output side BUR applies a pressing force to the work roll 2 from the center, so that it is curved in a C-shape toward the rolling direction.

FIG. 5 schematically shows the state of curvature (deflection) of the work roll 2. As shown in the figure, the work roll 2 is
The center of the arc shown by the axis 21 is in the direction of the center of the strip width of the rolling mill, as shown by the arrow. That is, both ends of the material rolled by the work roll formed in this manner tend to flow toward the center of the sheet width. This is different from the metal flow at the edge of the plate in normal rolling, and by the action of the force pushing the plate towards the center of the width of the plate, it is possible to prevent the thickness of the plate from decreasing at the edge. In particular, in a rolling mill as shown in Fig. 1, as the center axis of the work roll end side of the cluster mill deviates from the center axis of the lower large-diameter work roll, the roll gap becomes larger, and the end portion of the nap material becomes larger. Effectively reduces plate thickness.

The present invention adjusts the amount of displacement in the BUR of the cluster mill with the BUR on the entry side and the exit side, and actively gives curvature (deflection) to the backup roll in the horizontal plane, but also in the vertical direction. Bending, ie curving the work roll in both directions, is even more effective.

Curving in the vertical direction is performed by adjusting the BURs 5 and 6, but it can also be done by giving the center reinforcing roll 7 the same function as the side BUR 56, or by adjusting the work roll 2.
This may be done by applying a pending force to the chock.

The maximum displacement d (Fig. 3) of the BUR according to the present invention is 1 to 2.
It is sufficient if it can be approximately m+s, and this value can be appropriately selected depending on the mill capacity, the intended characteristics of the rolled material, etc.

(Effects of the Invention) As explained above, according to the present invention, when hot rolling is performed using a cluster type rolling mill, the amount of displacement of the BUR of the mill is adjusted, and the work roll is shaped into a C-shape in the rolling direction. By bending the material to the desired angle or even in the vertical direction, it is possible to effectively prevent the reduction in thickness at the width end of the rolled material, that is, edge drop, and produce hot rolled material with a high rolling yield. can do.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a partially detailed perspective view of the cluster mill of the present invention, FIG. 3(a) is a side explanatory view showing displacement in the cluster mill of the present invention, and FIG.
) is an explanatory diagram showing the state of deflection of a small-diameter work roll, FIG. 4 is a diagram showing an example of a developed view of implementing the present invention, and FIG. 5 is a schematic diagram showing the state of the work roll during rolling. 1...Cluster mill 2...Small diameter work roll 3.4...Intermediate roll 5.6...Side reinforcement roll 7...Center reinforcement roll 8...Large diameter work roll 117, 101-105 ...Divided small roll 11...
Sleeve 12...Bearing 13...Eccentric bush 14...BUR roll shaft 15...
Support arm 16... Movable shaft 17... Rotating shaft 18... Rack gear 19... Rolling progress direction 2o... Rolled material 21... Axis center of work roll

Claims (3)

[Claims] (1) In a cluster rolling mill with backup rolls divided in the width direction, the amount of displacement of the backup roll in the roll axis direction is set in opposite directions for the backup roll on the entry side and the backup roll on the exit side, and A hot rolling method using a cluster rolling mill characterized by rolling with the axial direction deflected in the horizontal direction. (2) The hot rolling method using a cluster type rolling mill according to claim 1, wherein the axial direction of the work roll forms a C-shaped bend on the rolling surface. (3) The hot rolling method using a cluster type rolling mill according to claim 2, wherein the axial direction of the work roll is further displaced vertically in a concave manner.