JPH03294007A - Four high rolling mill and rolling method - Google Patents

Abstract

PURPOSE:To unite control characteristics an excellent in plate crown and plate shape and schedule-free rolling to freely set the order of width of a rolled stock by changing equivalent roll crown effectively through roll shift. CONSTITUTION:Curved initial crown parts 1a, 2a of a n-dimensional expression (n>=1.5) are provided respectively on one side from the central part of the drum length of each operating roll 1, 2 and practically cylindrical initial crown parts 1b, 2b are provided respectively on the other side from the central part of the drum length of each operating roll. Each of these work rolls are arranged structurally so that these curved initial crown parts take opposite positions in the directions of the roll axes. In rolling a large width stock, the equivalent roll crown is made small by the combination of the curved initial crown part and the cylindrical crown part. Further, in rolling a small width stock, an area of a plate width governed by the curved initial crown part of this n-dimensional expression is increased to accomplish the object by moving the operation rolls mutually.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a work roll shift type four-high rolling mill, which greatly increases the ability to control the plate crown and plate shape of rolled material, and also improves roll wear dispersion. The present invention relates to a four-high rolling mill and a rolling method that realize schedule-free rolling.

[Conventional technology]

In recent years, a function required of rolling mills, especially hot slip mills, is schedule-free rolling. What is schedule-free rolling?

Instead of changing the width of the rolled material in one direction from wide to narrow sequentially as in the conventional rolling schedule, the width of the rolled material can be freely selected without any restrictions on the order of the width of the rolled material. This groundbreaking technology, which requires the ability to roll sheets with excellent crown and sheet shape, has only recently been realized. This rolling mill is applied to a six-high mill of the type called HCMW mill described in Japanese Patent Publication No. 51-7635, and the plate crown and plate shape of the rolled material are controlled by an intermediate roll shift and a work roll bender. By cyclic work roll shifting, the body surface of the work roll, which conventionally wears into a box shape, has a smooth profile, and the rolling schedule of the rolled material can be reversed from narrow width to wide width. . Therefore, this method inevitably results in a six-stage mill that requires intermediate roll shifting and work roll shifting. In the tandem finishing mill of a hot strip mill, the drive torque of the stand on the latter stage is small, and the plate thickness is thin, so the roll diameter of the work roll can be made small from the top of the threading process, so even if a 6-stage mill is adopted. The structure of the rolling mill does not have to be huge, but on the other hand, the stand on the front stage requires a large diameter work roll, so a six-tier mill would be huge. Modification of the mill is virtually impossible. However, in recent years, the thickness of sheets produced in hot strip mills has been getting thinner year by year, and accordingly, the ability of the rolling mill in the front stand to control the strip rolling under schedule-free conditions without restrictions on the order of rolled sheet width has been increasing. It has become a need.

To achieve this, it is necessary to use a four-stage mill to perform this function.There are various ways to control the plate crown using a four-stage mill, such as roll bending, but none exists that can meet the above requirements. In the work roll shift type four-stage mill called the HCW mill described in Publication No. 7635, if the work roll does not have a convex or concave roll crown on the roll body surface, a work roll bender is used to reduce the plate crown. Even at the maximum, it is necessary to move the effective length end of the work roll to near the width end of the rolled plate to perform rolling, but when the rolled material deviates from the center of the mill, the rolled material comes off from the body of the work roll. There is. In addition, when using this method to perform a cyclic shift to reciprocate the work roll to disperse wear, the amplitude of the cyclic shift requires approximately +100 degrees, so the body end should be 200 degrees from the plate end.
m or more, and in this case, the roll bending equipment does not have any extra strength of the bender to correct the plate crown.8 Although this point can be improved by attaching a roll crown to the body surface of the work roll, the plate In order to prevent the plate crown from becoming concave when the width is wide, the convex roll crown is limited to a small amount, so there is a problem that the plate crown is not effective at narrow widths.

If a decrease bender is applied to such a rolling mill, it is possible to increase the roll crown, but the decrease bender has the disadvantage that it sometimes has to switch to roll balance when removing the bottom of the plate, making threading unstable. There is. Furthermore, in this HCW mill system, the contact load with the reinforcing roll at the body end of the work roll is high, which shortens the life of the reinforcing roll, especially in heavy load rolling.

Therefore, conventional HCW mills have been generally used as a measure against roll wear. By the way, Japanese Patent Application Laid-Open No. 57-91807
There is a work roll shift type mill shown in the publication. Moreover, an S-shaped uneven roll crown is formed on the roll body surface of this work roll, and the upper and lower work rolls are exactly 1
The mill is configured so that the relationship is turned 80 degrees. And this mill has one work roll profile S
The shape of the axial roll gap between the rolls is changed mainly geometrically by shifting the work rolls, and the feature is that the change in the plate crown relative to the amount of shift is large. In that case, the effect of a large work roll bender such as an HCW mill, in which the reinforcing roll body length and the work roll body length are in contact over almost the entire length, cannot be expected.

If roll wear is distributed by cyclically shifting the work rolls in this type of mill, the plate crown will be significantly disturbed. The shift amount of the work roll in the mill is ±1
The plate crown control changes from the maximum to the minimum.

By the way, if the work roll is cyclically shifted by ±100 m to disperse roll wear, the plate crown will cyclically fluctuate to the maximum, so this plate crown variation cannot be corrected by a less effective work roll bender.

In other words, although the above type of mill has the ability to control the plate crown, it is not capable of schedule-free rolling.

In addition, a four-stage mill called a pair cross mill described in JP-A-55-64908 is known as a four-stage mill with a large plate crown control amount.

In this type of mill, upper and lower work rolls and reinforcing rolls are crossed with each other so that the roll axes intersect in the bubble plane, and the plate crown is controlled by changing the vertical roll gap distribution. .

In this mill method, if only two work rolls are crossed,
Slippage occurs between the reinforcing rolls, resulting in roll wear and huge thrust, so the reinforcing rolls that carry the rolling load must also be crossed together, resulting in a large and complex mill structure. Further, the spindle for driving the work rolls is preferably a universal joint with a large angle because in addition to the angle that follows the change in the vertical position of the work rolls, there is also an inclination angle for crossing in the horizontal direction, increasing the total angle. However, since fluctuations in rotational speed occur due to the horizontal inclination angle, there are restrictions on the cross angle, which necessitates the adoption of a gear type spindle oriented at a low angle.

Furthermore, in order to realize schedule-free rolling with this pair cross mill, a major problem is how to deal with wear of the work rolls.

One of the countermeasures is to add a function to shift the work roll in the axial direction. However, this method requires an additional axial shift mechanism to be added to the horizontal cross work rolls, making the structure extremely complex, making it difficult to use the mill in harsh environments where loads, shocks, heat, and water are present. , it would impose an excessive burden in terms of reliability and maintenance.

Another method is to install a roll grinder in a rolling mill, as shown in JP-A-54-145356, so that even if wear occurs, the roll crown of the work roll is maintained at the same level as before wear occurred. This involves grinding the barrel surface. Current methods have been attempted, but they are extremely expensive and only have the ability to smooth out stepped wear, making it difficult to adequately compensate for roll wear, and requiring maintenance costs such as replacing grinding wheels. Schedule-free rolling using this method cannot be said to have been achieved, and even if achieved in the future, it cannot be said to be an economical method.

[Problem to be solved by the invention]

As mentioned above, in conventional 4-stage mills, plate crowns are used.

Both sufficient control of the plate shape and schedule-free rolling were not satisfied.

One of the objects of the present invention is to provide a 4-high rolling mill that can handle all rolling conditions with the same work roll and that has both the function of ensuring an optimal plate crown and plate shape and the function of being able to perform schedule-free rolling. The object of the present invention is to provide a rolling method.

Another object of the present invention is to make it possible to increase or decrease the amount of one equivalent roll crown to a desired value by shifting the work roll in the axial direction, and to prevent fluctuations in the amount of equivalent roll crown within the range of reciprocating shifts of the work roll. An object of the present invention is to provide a four-high rolling mill and a rolling method that make it possible to suppress the above.

[Means to solve the problem]

In order to achieve the above object, the present invention provides upper and lower work rolls, upper and lower reinforcing rolls that support the work rolls, a roll bending device that applies bending force to the work rolls, and a roll bending device that bends the work rolls in the roll axis direction. and a roll shift device for moving each work roll,
A curved initial crown portion approximated by a curve of an n-dimensional equation (n≧1.5) formed on one side of the roll cylinder in a range from a predetermined position of the roll cylinder length to one end of the roll, and a predetermined roll cylinder length. A substantially cylindrical initial crown portion formed on the opposite side of the roll cylinder in a range from the position to the other end of the roll is provided on the surface of the roll cylinder, and further, each work roll has a substantially cylindrical initial crown portion formed on the opposite side of the roll cylinder in a range from the position to the other end of the roll. The four-high rolling mill is constructed by arranging the initial crown portions at opposite positions in the axial direction of the rolls.

Further, the present invention includes a work roll having a roll bending device, a reinforcing roll that supports the work roll, and a roll moving device that moves the work roll in the axial direction, and the work roll has a roll body length. A curved initial crown portion approximated by an n-dimensional equation (n≧1.5) formed on one side.

A cylindrical initial crown portion formed on the other side of the roll body length, and each of the work rolls is a four-high rolling mill arranged such that the initial crown portions have a point-symmetric relationship with each other. The axial position of the work roll is set so that the effective body end of the roll is located outside the width end of the rolled material plate, and the axial position of the work roll is set within a predetermined range as the rolling work progresses. The above object is achieved by configuring the rolling method so that the work rolls are moved back and forth within the working rolls, and the work rolls are moved in opposite directions.

[Effect]

In the present invention, the work roll has a curved initial crown part of an n-dimensional formula (n≧1.5) on one side from the center of the body length of the work roll, and a substantially cylindrical crown part on the other side from the center of the work roll body length. In addition, each of the work rolls is arranged such that the curved initial crown parts are at opposite positions in the roll axis direction, so that when rolling a wide material, the above-mentioned By combining the curved initial crown part and the cylindrical crown part of the n-order formula, the equivalent roll crown is made small, and when rolling narrow material, the work rolls are mutually moved to achieve the n-order formula. The above object can be achieved by enlarging the plate width region dominated by the curved initial crown portion.

〔Example〕

Before explaining one embodiment of the present invention, the present invention will be explained in detail.

In other words, the four-high rolling mill according to the present invention must have the following functions.

1) Cyclic shifting of work rolls is the most economical and rational method for dispersing roll wear, so the system should have this function.

2) In order to perform a cyclic shift, it must have the ability to reduce the plate crown even if the end of the work roll is separated from the edge of the plate. For this purpose, it is desirable that the roll has a crown.

3) In order to exert a work roll bending effect sufficient to compensate for fluctuations in the plate crown by cyclic shifting, it is desirable that the work roll end is not too far away from the plate end.

4) It is desirable that the roll crown mentioned in 2) be as large as possible when the strip width is narrow, but it will be too large in wide width rolling, so if the work rolls are shifted according to the strip width, the strip width will be wider. Ideally, the roll crown would be small, and as the board width becomes narrower, the roll crown would become larger.

5) Furthermore, it would be more ideal if fluctuations in the roll crown were suppressed under cyclic shift.

Therefore, in the present invention, the above five items are realized by a four-high rolling mill having a construction in which a special initial crown is provided on the work roll and the work roll is movable relative to each other in the axial direction.

That is, in the four-high rolling mill of the present invention, an initial crown portion having a curved shape of the n-th order formula (n≧1.5) is formed on one half of the body length of the work roll, and a substantially curved initial crown portion is formed on the other half of the body length of the work roll. By providing a cylindrical initial crown part in the rolling material, the equivalent roll crown due to the combination of the curved initial crown part and the cylindrical crown part is reduced when rolling a wide material, and when rolling a narrow material, this work roll The above five items are achieved by increasing the plate width region dominated by the curved initial crown portion by relatively moving the curved initial crown portion in the axial direction, thereby enlarging the equivalent roll crown.

The basic concept of the present invention described above will be explained using FIGS. 1 to 4. In FIG. 1, the upper and lower work rolls 1 and 2 that roll the rolled material 3 are supported by reinforcing rolls 21 and 22, respectively. This is a four-high rolling mill. Note that the work roll bending device and the work roll shifting device are not illustrated here.

The special roll crown shown in FIG. 1 is a feature of the four-high rolling mill according to the present invention, and each of the upper and lower work rolls 1°2 has a crown amount CR of n on only one side starting from the center of the roll body length. Curved initial crowns la and 2a of the following formula (n≧1.5) are provided, and the other side is a substantially cylindrical initial crown lb and 2b. The curved initial crowns la and 2a are set to be located on opposite sides in the axial direction. This is similar to the conventional roll crown, that is, the work rolls 1' and 2' are provided with roll crowns lc and 2c that are 1/2 of the CR if converted into roll crowns that are symmetrical and the same roll crown for the upper and lower work rolls as shown in Fig. 2. This corresponds to the four-high rolling mill shown. In the state of the work rolls in FIG. 1, only the curved roll crown 1a of the upper work roll 1 on the right side and only the curved roll crown 2a of the lower work roll 2 on the left side act as roll crowns. Next, when the plate width of rolled material 3 narrows from the maximum B, &8 to B, the third
Shift work rolls 1 and 2 as shown in the figure.

In such a case, the rolling area of both the upper and lower work rolls 1 and 2 with the curved roll crowns la and 2a increases, that is, the crown increases, and when B becomes about 1/2 of Bmax, almost the full width of the board is reached. Both the upper and lower work rolls 1 and 2 have curved roll crowns la.

Rolling is carried out in a certain roll region 2a, and the crown effect is equivalent to that of a conventional sheet having twice the crown when extended to the maximum sheet width as shown in FIG. still,
In the conventional roll crowns lc and 2c as shown in FIG. 2, the change in plate crown due to roll shift is small, and especially in the normally used quadratic curve roll crown, the effect is zero. Therefore, if roll crown CR' is provided on the side where curved roll crowns la and 2a are not provided in Fig. 1, the amount of plate crown will increase accordingly, and the effect of roll shift will not exist with a symmetrical crown, so it will not affect roll shift. The number of valid rounds decreases to CR-CR', which defeats the purpose.

The curved one-side rolled crown la shown in FIG.

2a is mainly a quadratic curve as expressed by the n-dimensional equation (n≧1.5), but let's examine how the roll crown effect due to roll shift changes depending on the type of this curve.1
Curved roll crown la.

2a curve with the roll center point as the origin, Y=CRXr'
, or dimensionless roll axis direction coordinates.

If the work rolls 1 and 2 are shifted by S based on the state shown in Fig. 1, the distribution of the roll gap, that is, the plate width, becomes -S < X KS (1) In the range, C(X) = 2
When CRX"X is in the range of 1≧X, ≧, S or -IKX<-8, C(X)=C*((X+S)"-2S")
−(1).

Although such a roll curve cannot be expressed by a single equation, it can be seen in Fig. 5 that it is a smooth curve whether n=2, S=O or S=0.5.

For the entire roll length (extended to Bmax to be exact)
The amount of crown Ct is the equivalent roll crown C at X=1
T is.

CT:CRlx:□=CR((1+S)"-28t')
-(2) When S=0, CT:CR.

Now, if CT at S=0.5 is CTE, and the crown increase rate α is α:CTE/CR, then α=CT18
:. ,,==CR((1+0.5)"-2X0.5")
XCR=1.5"-2XO,5".

α has no meaning unless it is 1 or more. The value of α with respect to the value of n is shown in FIG. 6. From this, it can be seen that n must be at least 1.5 or more. Also, JP-A-57-181
As shown in Japanese Patent No. 708, in the case of a roll having a tapered crown on one side of the roll end, that is, a straight taper where n=1 in the above equation, α=0.5, which has the opposite effect. The Taber method has already been used in the work roll shift mill described in JP-A-57-1.81708, which aims to improve the edge drop at the edge of the plate, and the roll edge is tapered. This is different from the four-high rolling mill of the present invention whose purpose is to control the crown of a sheet metal body. Moreover, in narrow width rolling, the equivalent crown decreases and the objective cannot be achieved.According to Figure 6, the larger n is, the larger α becomes, but if n is too large, there will be a difference with the deflection characteristics of the work roll. Since the crown becomes a composite crown, it is better to keep the maximum value of n to 2.5 times.

Figure 7 shows how the crown increase rate α changes with shift S for n = 2.0 and n = 2.5. Although the crown increase rate due to the work roll shift increases, if it becomes too large, the crown fluctuation due to the cyclic shift for dispersing roll wear will become too large, so it is not a good idea to make n too large. I have already mentioned that it is essential to disperse the roll wear that occurs on the work rolls, but what is important is that.

Many hot strip mills have roll surface lengths that can roll wide strips, such as the maximum strip width of 1,600 m, 1,800 m, or even 2,000 mm, but the average strip width is around 1,000 m, which is the minimum strip width. The width is about 600 m, therefore, the amount of rolling is the largest for strips with a width of around 1000 a, and the wear of the rolls is the most severe for these widths. Therefore, a cyclic shift of the work roll for wear dispersion is most necessary for these widths, and in this case, it is desirable that the fluctuation of the roll crown due to this shift be as small as possible. The present invention provides extremely effective means for these as well. The effects of the present invention in this respect will be described below. The roll crown type of the work roll in the four-high rolling mill of the present invention shown by the formula (1) is n=2C(X)"CR((X+S)"-2
8”)=CR(X”+28X”-S”)
...(3) The change ΔC(X) in C(X) when S is changed by ΔS is...(4) Now, if the arbitrary sheet width is B, the position of the rolling roll -
b/b-ax≦X S Only b/b-ax is a problem here, and if its end is Xb, then Xb=b/b, &
.

Then, A C(Xb) = 2 CRCXb-S )ΔS
-(5) Now, Xb"1. That is, when b=b-a-, S is close to zero, so ΔC(Xb)lx, staff 2CP+(1-0)Δ5==2C
*ΔS, but as mentioned above, if the board width is about half of the large board width, b
= b −ax/ 2, xt, = 0.5, S also b
Since it is shifted by maX-b, it is made dimensionless and becomes 5=(b
,,.

-b)/b, n=0.5, and using equation (5), A
c(xb) Peng. ,, = 2 CR(0,5-0,5)
As A S = 0, almost no crown fluctuation occurs due to roll shift.

In addition, when b<o, sb, □, S2O,5 and the rolled material is
Since both rolls are rolled between quadratic roll curves, no geometrical variation of the initial crown due to roll shift occurs. Incidentally, if b = 0.5 b□, and if it is desired to prevent geometrical crown fluctuation due to shift, this can be done by further extending the starting point of the initial crown of the work roll to the straight side.

What I would like to emphasize here is whether there are any other special roll crowns that have this kind of effect. This will be discussed using the S-shaped roll curve described in the above-mentioned Japanese Patent Application Laid-Open No. 57-91807.

As mentioned above, the type of mill with the S-shaped roll curve has a small roll shift stroke and the crown change due to roll shift is extremely large, so cyclic shifting is impossible. A possible solution would be to make the crown smaller and increase the roll stroke accordingly. However, in the above-mentioned type of mill, the roll curve is actually a Sing curve or an odd function such as Xb, and the geometric effect thereof is, for example, XJL.

Y(X)"((X+S)"-(X-8)")Ca=(6
SX"+2SCRC(X)"Y(X)Y(0)=6C
R8X"---(6) The change ΔC(X) in C(X) when So is moved by ΔS is proportional to ΔS regardless of the position of the neighbor S.

The equivalent Clara 2C for the entire length of the roll is X=1 and Ct=6CR8 from the formula (6), which is S.

On the other hand, if the above-mentioned special crown according to the present invention is used as the initial crown of the work roll, within the range of the plate width (
From Equations 4) and (5), S If this is expressed as the equivalent Clara 2C of the full length of the roll, the roll curve becomes a quadratic curve...(8) In this case, the work roll is rotated along the axis by S in response to changes in the seat. direction, but when Xb=1, S=0°X b =0
, 5, S=0.5, so Xb+S=1. However, when S<0.5, as mentioned above, the roll curve applied to the SS-shaped crown roll mill and the work roll of the rolling mill according to the present invention becomes δS.

In Fig. 8, curve (A) shows the case of the roll crown of the present invention, and curve (C) shows the case of the S-shaped roll crown. Accordingly, large fluctuations in the plate crown cannot be avoided, whereas with the roll crown of the present invention, it is possible to suppress fluctuations in the plate crown to a small level by roll shift (while ensuring a sufficient roll crown as an absolute value). I know what I can do. That is, for example, in a typical wide hot strip mill, the roll surface length is 2200y.
In xa, the maximum board width is 2000m, the minimum width is 600mm, and the highest production volume is around 1000mm board width, and as shown in Figure 8, Xb = 0.5. This corresponds to S=0.5. Also, for the 1200m plate width, which has a relatively large production volume, X b =0, 6,
S = 0, sXb corresponding to 4 is 0.6 or less and known S
It can be said that there is much less plate crown variation due to roll shift than with a letter-shaped roll crown, and it can be seen that schedule-free rolling can be performed very effectively by the rolling mill of the present invention.

Next, a four-high rolling mill which is an embodiment of the present invention is shown in FIGS. 9 to 11. FIG. 9 is a structural diagram of the above-described four-high rolling mill viewed from the roll axis direction, FIG. 10 is a front view of the rolling mill viewed from the operating side, and FIG. 11 is the XI-
It is a sectional view in the XI direction.

In these figures, 1 and 2 are a pair of upper and lower work rolls for rolling the rolled material 3, and these work rolls 1,
2 is supported by reinforcing rolls 21,22. Roll neck portions at both ends of the work rolls 1, 2 are rotatably supported by metal chocks 4, 4' and 5, 5', respectively. Further, a project block 7.8 is attached to the window formed in the roll housing 6, and a shift block 9.8 is attached to the project block 7.8.
10 is installed. Metal chocks 4, 5 are slidably guided inside the shift block 9, 10, and the metal chocks 4, 5 can vertically move up and down together with the work rolls 1, 2. Furthermore, shift block 9. Hydraulic rams 11 and 12 for applying roll bending force to the work rolls 1 and 2 constituting the roll bending device are appropriately built into the roll bending apparatus.

On the other hand, the shift block 9 constituting the roll moving device
is connected to the shift beam 13 on the rolling mill drive side,
Also, the drive side metal chock 4' is also chock clamp 14.
The shift beam 13 is removably connected to the shift beam 13 through the operation of a hydraulic cylinder 15. Therefore, the upper work roll 1 can be moved in the roll axis direction together with the shift block 9 by the roll shift hydraulic cylinder 16, and the upper metal chocks 4, 4' and the hydraulic rams 11 and 12 built in the shift block 9 can move the upper work roll 1 together with the shift block 9. Since it will be moved in the axial direction, even if the upper work roll 1 is moved over a long stroke,
The roll bending force can always be applied to the center of the bearing 17 of the work roll, and a large roll bending force can be applied to the roll while ensuring the life of the bearing.

Further, 18 is a drive shaft for rotationally driving the upper work roll 1, and the upper work roll 1 is driven via a coupling 19 by a motor (not shown). In this case, the center portion 20 of the shift beam 13 may have an appropriate shape (for example, a hanging shape) so that the shift frame 13 and the drive shaft 18 do not interfere with each other.

Although not shown, if the same structure as above is adopted for the lower work roll 2, it is possible to effectively apply roll bending force while moving the upper and lower work rolls 1 and 2 in opposite directions in the axial direction.

Next, the upper and lower reinforcing rolls 21 and 22 are the upper and lower work rolls 1, respectively.
.

Now, FIG. 12 shows an example of roll initial crowns la and lb provided on the upper and lower work rolls 1 and 2. That is,
The work roll 1 with a roll body length of 2200 mm and a roll diameter of 780 mm is tapered from point A at the approximate center of the roll body toward one side of the roll end on the right side of the figure, and a quadratic curve is drawn over this region as y= A curved initial crown 1a having xz is provided, and the radius at eight points at the end of the roll body is smaller by 300μ than the diameter at point A. On the other hand, the part on the opposite side toward the roll end on the left side of point A is a straight-shaped, cylindrical initial crown lb whose diameter does not substantially change.
It becomes.

The approximate formula for the curved initial crown 1a formed on one side of the roll body surface of the work roll 1 is y=x! It is expressed by the formula of l. Here, the necessary effect can be obtained when n≧1.5, but preferably the range of n=2.0 to 2.5 is optimal.

Figures 13@ and 14 respectively show a four-wheel drive system, which is an embodiment of the present invention, and which is equipped with an upper and lower work roll having a curved initial crown of the y=x2 curve shown in Figure 12 on one side of the roll cylinder. In a high-high rolling mill and a conventional four-high rolling mill with symmetrical initial crowns over the entire length of the rolls shown in FIGS. The thickness distribution of the plate crown is shown under conditions where control is performed according to various plate widths. In Figures 13 and 14,
(A) is board width B = 1800cm, position δ between work roll end and board width end = 200mm, roll bender F = Oton
, 200ton/chi E': 1(7), (B) is board width B=1200m, δ=300m, F=0ton, 2
In the case of 00ton/chiE”/ri, (C) is the plate width B=90
0m, δ=300m, F=Oton, 200to mouth/
The cases of chock are shown respectively. In addition, all rolling loads are calculated on the basis of 1.75 tons per 1 inch of sheet width. Comparing these figures 13 and 14, case (A)
As mentioned above, the equivalent roll crowns are the same, and equivalent plate crowns are obtained. However, cases (B), (C
), when the plate width becomes narrow, the second embodiment of the present invention, the first
In the case shown in FIG. 3, the plate crown can be changed from convex to concave by changing the force F of the roll bender from Oton to a maximum of 200 tons/chock, and thus a flat plate crown can be obtained. In the case shown in FIG. 14 in which the conventional initial crown is applied, only a convex plate crown can be obtained.

This is because in the case of the conventional symmetrical roll crown, there is no geometric effect due to roll shift, and the effective body end of the work roll is outside the width end of the work roll because δ = 300-, which means that one work roll has no geometric effect. In contrast to the roll with the curved initial crown of the present invention, where the deflection is not sufficiently small and the plate crown has to become convex, the curved initial crown is directly shaped This is because the plate crown can be made sufficiently flat even if a certain degree of deflection of one work roll remains since the plate crown is changed in a specific manner. As shown in the figure, when the work roll is shifted significantly toward the center of the rolling mill, that is, toward the inside of the reinforcing roll body length, the geometric effect increases and the isometric initial crown increases, so the deflection of the work roll increases. It can be seen that this is particularly effective for rolling under narrow width and large δ conditions.

FIG. 15 shows the curved initial crown 1a of the work roll for a true rolled material having a sheet width of 1200 using a four-high rolling mill equipped with a work roll having the initial crown shown in FIG. 12 according to the present invention. In (A), δ = 100 m, and in (B), δ = 2.
0C)w+, (C) shows the roll bending roller F that can flatten the plate crown when the work roll is shifted within the range of δ=300−n and ±100 degrees, and the plate crown at that time. From FIG. 15, when the shift stroke of the work roll is within ±Loom, the roll bending force F is (A) F = 40 ton/chock, (
B) F=90ton/chiyoku, (C)F=1
40ton/Chock and all maximum bender force 200ton
It can be seen that the plate crown can be made sufficiently flat within the range of n/chok. Therefore, according to the four-high rolling mill of the embodiment of the present invention, the plate crown can always be kept flat within the amplitude of the cyclic shift necessary for dispersing the wear of the work rolls, and schedule-free rolling can be performed while ensuring the quality of the rolled material. It becomes possible.

16 and 17 show the work roll with the curved initial crown shown in FIG. 12 and the conventional 150
When rolling a plate crown of a rolled material with a width of 1200cm almost flat using a work roll shift type 4-high rolling mill equipped with work rolls with symmetrical initial crowns with a diameter difference of about μm. It shows the inter-roll pressure distribution between the work roll and the reinforcing roll. In order to obtain a flat plate crown even with the work roll with the conventional roll crown shown in Fig. 17, the rolls are shifted so that the effective body ends of the rolls are both 200 m outside the plate width edge (δ = 2oO
■). From these figures, it can be seen that the pressure distribution between the rolls is greatly different, and in particular, in the case of the four-high rolling mill of the embodiment of the present invention shown in Fig. 16, the maximum value of the pressure can be significantly reduced, so the strength of the rolls can be improved. It can be seen that this has a great effect on the lifespan. Therefore, in the case of the embodiment of the present invention, the frequency of rearranging the rolls is reduced, and the execution of schedule-free rolling can be further improved.

Regarding the roll initial crown according to the embodiment of the present invention described above, the starting point A of the curved initial crown 1a on one side of the roll body of the work roll 1 shown in FIG.
In order to ensure controllability of the plate crown during rolling of wide material, it is best to install it at the center of the roll cylinder as much as possible, but since the axial position of this work roll is variable, it is not necessary to set it strictly at the center of the cylinder; 0 that can be shifted left or right For example, starting point A
A little to the left from point A shown in Fig. 12, a relatively small curved initial crown is added toward the center, and further from the center of the roll cylinder, y=xn (n≧1
．． A curved initial crown of 5 to 2.5) may be attached.

And one side of the roll cylinder opposite the work roll 1.

Any substantially straight cylindrical initial crown 1b may be used.

In addition, as another embodiment, for example, if a special initial crown expressed by a quintic equation is used over the entire length of the effective side angle extending from the left end of the roll body length of the work roll to the right side of the roll body length, as shown in FIG. It is also possible to obtain an initial crown that is sufficiently similar to the embodiment of the roll crown shown in FIG.

FIG. 18 shows still another embodiment of the present invention.
This is an example in which the four-high rolling mill shown in Figures 3, 3, and 9 is applied to a 5-stand hot tandem mill.

In Fig. 18, the first to second stages of the tandem mill
A work roll shift type four-high rolling mill equipped with a work roll having a curved initial crown according to the present invention described above is applied to the rolling material of the stand, and intermediate rolls are used in the rolling mills of the remaining third to fifth stands. 31 is a shiftable six-high rolling mill shown in the above-mentioned Japanese Patent Publication No. 51-7635.

In the tandem mill described above, it is relatively easy to improve the existing equipment, and the functionality of the rolling equipment can be dramatically improved.

Incidentally, although the above-described embodiments of the present invention have been mainly described with respect to a hot strip mill, it goes without saying that the rolling mill of the present invention can also be applied to a cold strip mill.

〔Effect of the invention〕

According to the present invention, a four-high rolling mill equipped with an axial shift of work rolls having an initial crown as described above and a work roll bender allows rolling by effectively changing the isometric roll crown by roll shifting. Schedule-free rolling that allows you to freely set the order of the width of the material, and plate crown.

The present invention has the effect of realizing a four-high rolled material and a rolling method that enable rolling with excellent control characteristics of the plate shape at all times.

[Brief explanation of drawings]

FIG. 1 and FIG. 3 show the schematic configuration of a work roll shift type four-high rolling mill which is an embodiment of the present invention.
Figure 3 shows the situation when rolling a wide material, and Figure 3 shows the situation when rolling a narrow material. Figures 2 and 4 show a conventional four-high rolling mill equipped with work rolls with symmetrical roll crowns. Fig. 2 shows the situation when rolling wide material, Fig. 4 shows the situation when rolling narrow material, and Fig. 5 shows the work rolls of the four-high rolling mill of the present invention. An explanatory diagram of the relationship between the plate crown C(X) and the position in the roll axis direction in an example of a roll curve applied to the initial crown, FIG. An explanatory diagram of the relationship between the order of the following equation and the crown increase rate γ, and FIG. 7 is an explanatory diagram of the relationship between the axial shift and the crown increase rate γ in a work roll with an initial crown used in the rolling mill of the embodiment of the present invention. , FIG. 8 is an explanatory diagram of the relationship between the shift and axial position of a work roll with an initial crown used in a rolling mill according to an embodiment of the present invention and changes in plate crown, and FIGS. 9 to 12 are diagrams showing an embodiment of the present invention. This figure shows the specific configuration of an example 4-high rolling mill. Figure 9 is a detailed view of the 4-high rolling mill seen from the roll axis direction, and Figure 10 is a detailed view of the 4-high rolling mill seen from the operating side. Front view, No. 11! ii! I
10 is a sectional view in the Xia-XI direction of FIG. 10, and FIG. 12 is a partial view showing the initial crown shape of the work roll of the four-high rolling mill. FIGS. 13 and 14 are plate crown distribution diagrams showing the plate crown control status by the four-high rolling mill according to the embodiment of the present invention and the conventional four-high rolling mill, respectively, and in both figures, (A) is the plate crown distribution diagram. 11,800 mm, (B) shows the rolling status of a plate with a width of 1,200 m, and (C) shows the rolling conditions of a plate with a width of 900 m. Figure 15 shows the rolling of a plate with a width of 1,200 m using a four-high rolling mill that is an embodiment of the present invention. This figure shows a situation in which a flat sheet crown is obtained by shifting the work roll within a range of ±100 meters. In the figure, (A) shows the distance δ = 100 m between the sheet width edge and the effective body end of the work roll. (B) shows the rolling condition of δ=200■, and (C) shows the rolling condition of δ=300, respectively.
7@ is a diagram showing the inter-roll pressure distribution between a work roll and a reinforcing roll in a four-high rolling mill according to an embodiment of the present invention and a conventional four-high rolling mill, respectively, and FIG. 12
FIG. 2 is a tandem mill arrangement diagram showing a situation where the four-high rolling mill of the embodiment of the present invention shown in the figure is applied to the front stage of a tandem mill. DESCRIPTION OF SYMBOLS 1... Upper work roll, la, 2a... Curved initial crown, lb, 2b... Cylindrical initial crown, 2... Lower work roll, 3... Rolled material, 4, 5
...Chock, 6...Housing, 11.12...
- Hydraulic ram, 16... Hydraulic cylinder, 21... Upper reinforcing roll, 22... Lower reinforcing roll, 23.24...
Chock. CR Roll crown, δ... Roll shift position, S Fig. 1 Fig. 2 Fig. 49 Fig. 3 Fig. Fig. Fig. Fig. 0.2 0.4 0.6 0.8 Fig. Fig. Fig. 23.24 ...Chock 1゜Figure 1 Figure 3 Figure 3 (A) (B) (C) Figure 2 Figure 1 Figure 4 (A) (B) (C) Figure 15 (A) (B) (C) 111 Tori Kamo 6 Figure 7

Claims (1)

[Claims] 1. Upper and lower work rolls, upper and lower reinforcing rolls that support the work rolls, a roll bending device that applies bending force to the work rolls, and a roll shift that moves the work rolls in the roll axis direction. Each of the work rolls has an n-order type (n≧
1.5) A curved initial crown portion approximated by the curve shown in FIG. A four-high rolling mill characterized in that each of the work rolls is provided with a crown portion on the surface of its roll body, and each of the work rolls is arranged such that the curved initial crown portions are located at opposite positions in the roll axis direction. Machine. 2. The four-high rolling mill according to claim 1, wherein the predetermined position of the roll body length is approximately at the center of the work roll body length. 3. The four-high rolling mill according to claim 1, wherein the n-dimensional curve approximating the curved initial crown portion is preferably in the range of n=2.0 to 2.5 degrees. 4. The maximum shift amount of the roll shift device is set to about 1/2 of the difference between the maximum board width and the minimum board width.
corrugated rolling machine. 5. A work roll equipped with a roll bending device, a reinforcing roll that supports the work roll, and a roll moving device that moves the work roll in the axial direction, each of the work rolls having a predetermined roll body length. A curved initial crown portion approximated by the formula y=x^n (n≧1.5) on one side of the roll cylinder from the position to one end of the roll, and a curved initial crown portion approximated by the formula y=x^n (n≧1.5), and from a predetermined position on the roll cylinder length to the other end of the roll. Substantially cylindrical initial crown portions are formed on the opposite side of the roll body leading to the roll body, and each of the voice-making rolls is arranged such that the curved initial crown portions are at opposite positions in the roll axis direction. A four-high rolling mill characterized in that a rolling mill having the configuration described above is placed in the front stage of a tandem mill. 6. A work roll having a roll bending device, a reinforcing roll that supports the work roll, and a roll moving device that moves the work roll in the axial direction, the work roll being formed on one side of the roll body length. n-dimensional equation (n≧
1.5) A curved initial crown approximated by A four-high rolling mill arranged so as to have the following relationship, wherein the axial position of the work rolls is set such that the effective body end of the roll is located outside the width end of the rolled material plate, A rolling method characterized in that the axial position of the work roll is reciprocated within a predetermined range as the rolling work progresses, and the work rolls are moved in opposite directions. 7. The rolling method according to claim 6, wherein the work roll is moved so that the effective body end of the roll is located inside the effective body end of the reinforcing roll. 8. The rolling method according to claim 6, wherein the bending force applied from the roll bending device is adjusted in accordance with the reciprocating operation of the work roll so as to compensate for the crown change of the rolled material due to the movement of the work roll. . 9, comprising: an upper and lower work roll; an upper and lower reinforcing roll that supports the work roll; a roll bending device that applies a bending force to the work roll; and a roll shift device that moves the work roll in the roll axis direction; Each work roll has a curved initial crown that is approximated by a roughly quintic curve formed over almost the entire effective length of the roll, and furthermore, the upper and lower work rolls have a curved initial crown that is approximated by a roughly quintic curve. A four-high rolling mill characterized in that each of the four-high rolling mills is arranged in a bilaterally asymmetrical relationship and in a mutually point-symmetrical relationship.