JPS63264204A - Rolling mill - Google Patents

Abstract

PURPOSE:To properly control a thickness of a rolled stock and to improve the sheet thickness accuracy in the width direction by shifting and crossing a couple of rolling rolls crowned to meet specific equations by a point symmetrical diameter changing amount relating to an axial length from the longitudinal body center. CONSTITUTION:The equation I expresses variation amounts in diameter to coordinates (x) in the axial direction from the body center of a rolling roll. The equation II expresses roll gap variation amounts S1(x) in the case of shifting the roll. The equation III expresses roll gaps S2(x) in the case of crossing the roll at an angle theta. D shows a roll diameter. Therefore, the equation IV expresses roll gaps S(x) in the case of shifting and crossing the roll. A 1st term of the equation IV is a quaternary term and corresponds to compensational amounts of an edge drop 11b and a 2nd term of parabolic component corresponds to compensational amounts of a crown 11a. By crowning the roll to correspond those compensational amounts, a rolled sheet thickness is corrected, the roll cost is reduced, and the productivity is improved without preparating plural types of rolling rolls.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a rolling mill for flattening metal strip.

<Prior Art> In recent years, the requirements for precision of rolled products, especially the precision of plate thickness in the width direction of the plate, have become increasingly strict. As shown in FIG. 4, which shows the cross-sectional shape of the metal strip, the main causes of this thickness abnormality are the plate crown lla where the central part of the metal strip 11 in the plate width direction swells, and the plate crown lla at both ends in the plate width direction. From 2
There is an edge drop tib whose plate thickness decreases rapidly to about 5 to 50 II 1 m. Of these, the sheet crown lla distributed over the entire sheet width direction can be almost dealt with by making the rolling rolls cross each other. That is, as shown in FIG. 5, rolling rolls face each other vertically with the metal strip 11, which is the material to be rolled, in between!
2 and their reinforcing rolls 13 are tilted in opposite directions at the top and bottom in a plane parallel to the metal strip 11, so that the gap between both rolling rolls 12 widens toward the ends of the rolls, and the rolling rolls due to the rolling load This compensates for the deflection of 12.

On the other hand, as a technology to reduce edge drop llb,
As shown in FIG. 6, at one end of the opposite side of the upper and lower rolling rolls 14, there is a tapered part 1 whose diameter decreases by Wk toward the end.
4a, these rolls 14 are moved axially in opposite directions to roll both ends of the metal strip 11 in the width direction with the tapered portions 14a.

<Problems to be Solved by the Invention> The above-mentioned arrangement in which the upper and lower rolling rolls 12 are crossed cannot sufficiently cope with edge drop Ilb.

That is, in order to compensate for the edge drop 11b, it is necessary to increase the cross angle of the rolling rolls 12, but if the cross angle is too large, the thickness distribution in the entire strip width direction will deteriorate, and the flatness of the metal strip 11 will also deteriorate. It becomes impossible to maintain it. This is because the deflection of the plate crown lla and the rolling roll 12 is close to a parabola (quadratic curve), whereas the edge drop flb is caused by concave deformation of the roll surface, and the amount of concavity at the edge of the plate width. This is because it is a high-order curve that changes suddenly.

On the other hand, if the tapered portion 14a is provided at the end of the rolling roll 14, the edge drop l
lb can be reduced. In this case, it is necessary to change the taper amount of the taper portion 14a every time the plate thickness or rolling reduction rate changes. Therefore, in order to perform various rolling operations, various types of replacements are required in advance. It is necessary to prepare rolls for use and replace the rolls each time, which leads to problems such as a decrease in productivity and an increase in roll costs.

The present invention solves these problems in conventional rolling mills, and aims to provide a rolling mill that can appropriately control plate crown and edge drop through simple operations.

Means for Solving the Problems> The rolling mill according to the present invention that solves the above problems has a diameter change amount of a with respect to the coordinate X taken in the axial direction from the center of the body length.
a pair of rolling rolls provided with a crowning given by x5-bx''-ax and arranged point-symmetrically with respect to each other; roll shifting means for relatively moving the rolling rolls in the axial direction; The present invention is characterized by comprising roll crossing means for tilting the rolls in opposite directions in a plane parallel to the rolled material.

<Operation> When the roll shift means moves the rolling rolls in the axial direction by ΔX in mutually opposite directions.

The gap distribution ΔS l (X) between both rolling rolls is ΔS+ (
X) = IOaΔx-x'+ 2(IOaΔx3-b
) ・Given by x2. On the other hand, if the rolling rolls are inclined by the roll crossing means and the crossing angle formed by one rolling roll is θ, then the gap distribution Δ52(X) between the rolling rolls is given by: Here, D is the diameter of the rolling roll, and the diameters of both rolling rolls are assumed to be equal.

Therefore, the gap distribution Δ5(x) created between both rolling rolls by these is as follows: Δ5(x)=Δ5l(X)+Δs, (X).

In the above formula Δ5(x), the high-order component of the first term is made to correspond mainly to the edge drop, and the parabolic component of the second term is made to correspond to the plate crown to compensate for the plate 79 distribution. That is, the edge drop is first compensated for by moving the mill rolls axially in opposite directions, and the resulting changes in the sheet crown are compensated for by tilting the mill rolls in opposite directions.

Embodiment Hereinafter, an embodiment of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a front view of a flattening machine according to an embodiment of the present invention, and FIG. 2 is a plan view thereof. In Figures 1 and 2,
21 is a metal strip which is a material to be rolled, 22 is a rolling roll provided with the crowning according to the present invention, and 23 is a reinforcing roll.

As shown in FIG. 1, a pair of rolling rolls 22 are provided one below the other with the metal strip 21 in between, and both ends of the rolling rolls 22 are supported by bearing boxes 24, respectively. Further, each of the rolling rolls 22 is provided with a reinforcing roll 23, and both ends of each reinforcing roll 23 are provided with bearing boxes 25, respectively.
These bearing boxes 25 are supported by a bearing box holding block 26, while the bearing box 24 of the rolling roll 22 is held by the bearing box 25 of the reinforcing roll 23 so as to be movable in the axial direction. The bearing 3@24 of this rolling roll 22 has a moving device 27 as a roll shifting means.
is attached, and by pushing and pulling the bearing box 24 with this moving device 27, the upper and lower rolling rolls 22 can be moved in their respective axial directions.

As shown in FIG. 2, the side surface of the bearing box 25 of the reinforcing roll 23 (the surface located in the front and rear of the conveyance direction of the metal strip 21)
A concave liner 28 is attached to each, and
A housing 31 includes a cylinder 30 having a pressing portion 29 having a convex curved surface that fits into and presses the liner 28.
These components constitute a roll cross means. That is, by extending one side of the cylinders 30 facing each other across the bearing box 25 at one end of the reinforcing roll 23 using the hydraulic supply device 32 and shortening the other, the bearing box 25 is moved, for example, to the front side in the conveyance direction of the metal strip 21. At the same time, the reinforcing roll 23 is conveyed with its axis parallel to the metal strip 11 (horizontal plane) by similarly moving the reinforcing roll 23 backward in the conveying direction. By tilting the upper and lower reinforcing rolls 23 in opposite directions, it is possible to make the upper and lower reinforcing rolls 23 cross when viewed from the vertical direction. be. Bearing box 24 of rolling roll 22
is surrounded by the bearing box 25 of the reinforcing roll 23, so the rolling roll 22 is inclined in the same way as the reinforcing roll 23. Note that the four cylinders 30 may be operated in conjunction with each other, or may be operated independently of each other. Further, the roll shift means can also be configured to directly tilt the rolling roll 22.

Further, in the rolling roll 22 according to the present invention, the amount of change in diameter with respect to the coordinate X taken in the axial direction from the center of the body length is c, (x) = ax' - bx2 - c (a>0, b≧ 0, c > O) ・・・・・・(1)
The upper and lower rolling rolls 22 are arranged symmetrically with respect to each other.

In such a rolling roll 22, first consider the relative gap between the lower rolling rolls 22 when they are moved by ΔX in mutually opposite directions in the axial direction. First, if the upper and lower rolling rolls 22 are expressed in a common coordinate system, the upper rolling roll 2
2 as cr-t(x)=a xS-b x' -c x
----If (2) is used, the lower rolling roll 22 is point symmetrical, so C, -2(X) = a (-x)5-b (-x)"
-c (-x)=-ax5-bx'+cx...
...(:]).

Now, if both rolling rolls 22 are moved in opposite directions to each other by ΔX, the axis of point symmetry will not move too much, so
The roller rolling of the upper and lower rolling rolls 22 at the position of
Each is given by the following formula.

cr-+(x+Δx) -a (x+Δx) 5-b
(x+Δx) 2-c (x+Δx)...(4) Cr-2(X-Δx)-a (x-Δx) ”b (x
-Δx)"+c(x-Δx)...(5) Therefore, at this time, the gap ΔS+(X
) is obtained by adding equations (4) and (5), ΔS+ (x) 1−
Cr-+ (x÷Δx) ”Cr-2(X-AX)-a
(10Δx”x'÷20Δ×3・×2÷2Δxs)−b
(2x2+2Δx")-2cΔX = 10aΔx-x'+2 (10aΔx'-b)x2+
(2aΔx'-2bΔx2-2cΔX) Here, since the third term is unrelated to X, the relative gap between the two is given by the following equation.

ΔS, (x)-IlOaΔx-x'+2 (10aΔ×3
-b)×2 (6) Next, consider the relative gap between the rolling rolls 22 when they are inclined and crossed at a cross angle θ when viewed from above and below. Now, Figure 3 (
As shown in a), the roll center deviation δ at a position X@ away from the intersection O of both rolling rolls 22 crossing at a cross angle θ is also equal to the roll diameter of both rolling rolls 22 being D.
Then, from FIG. 3(b), the gap Δ52(X) between both rolling rolls 22 at the position of X is Δ52(X)=
! D) 2-D Here, δ(D, so ΔS, (X)AID (1+2(P)) -D=stop
...(8) From equations (7) and (8), the gap ΔS is the sum of the gap Δs 1 (x) due to the above axial movement and the gap Δ52 (X) due to roll cross.
(x) is obtained by adding Equations (6) and (9), and in Equation (10), since the first term is a high-order quartic equation, it mainly corresponds to edge drop compensation, and the parabola of the second term is The components may be adapted to compensate for the plate crown. As a result, by changing the axial relative movement amount of the rolling roll 22 and the roll cross angle of the rolling roll 22, the required amount of roll gap compensation given from the target edge drop amount and plate crown amount can be adjusted independently. can be controlled; That is, in order to compensate for the edge drop, first the rolling rolls 22 are moved in opposite directions in the axial direction,
The resulting changes in plate crown may be compensated for by tilting the rolls 22 in opposite directions and crossing them. Moreover, in order to compensate only for the plate crown, this is mainly done by crossing the rolling rolls 22.

Incidentally, since it is necessary to make a plate with a large plate crown in rolling, it is desirable that the coefficient S is b≧10aΔ×, □3, where the maximum amount of roll movement is ΔX and IIM.

Further, although the coefficient C has no relation to the plate thickness compensation performance, it is preferable to select a positive value because the difference in roll diameter can be reduced by changing the coefficient C.

<Effects of the Invention> As described above in detail with reference to one embodiment, according to the present invention, edge drops can be compensated for by shifting the rolls, and sheet crown can be compensated for by rolling the rolls. Since it is possible to compensate for this, it becomes possible to appropriately control both the plate crown and edge drop with simple operations, and it is possible to significantly improve the plate thickness accuracy in the width direction of the rolled material. Therefore, it is possible to use even the width end portion, which was conventionally cut off because it was outside the allowable tolerance, as a product, and the yield can be significantly improved. In addition, by applying one type of roll crowning to a rolling roll, it can be applied to rolling operations of various specifications, so there is no need to prepare multiple types of rolling rolls, reducing roll costs and improving productivity. can contribute.

[Brief explanation of the drawing]

Fig. 1 is a front view of a rolling mill according to an embodiment of the present invention, Fig. 2 is a plan view thereof, Figs. 3 (a) and (b) are explanatory diagrams at the time of roll crossing, and Fig. 4 is a plate thickness. A cross-sectional view of a metal strip showing the distribution, and FIGS. 5 and 6 are conceptual views of a conventional rolling mill. In the drawings, 21 is a metal strip, 22 is a rolling roll, 27 is a moving device, and 30 is a cylinder.

Claims (1)

[Claims] A pair of rolling rolls that are crowned so that the amount of change in diameter is given by ax^5-bx^2-cx with respect to the coordinate x taken in the axial direction from the center of the body length, and are arranged point-symmetrically to each other. and roll shifting means for relatively moving the rolling rolls in the axial direction, and roll crossing means for tilting the rolling rolls in opposite directions in a plane parallel to the rolled material. rolling machine.