JP3040063B2 - Rolling mill and rolling method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling mill and a rolling method, and more particularly to a rolling mill and a rolling method suitable for reversing hard and ultra-thin materials using small-diameter work rolls.

[0002]

2. Description of the Related Art Conventionally, small diameter work rolls have been used for rolling hard and ultra-thin materials. However, as the roll diameter decreases, the bending stiffness decreases, and the deflection in a horizontal plane becomes a problem. For this reason, a multi-high rolling mill such as a Sendzimir mill or a support roll for supporting the work roll body from the horizontal direction as disclosed in JP-A-60-18206 is provided to prevent horizontal deflection of the work roll. Machine has been considered. However, in these rolling mills, since a support roll divided in the roll body length direction is used, there is a problem that mark transfer by the divided rolls deteriorates material surface properties. Therefore, a rolling mill disclosed in Japanese Patent Application Laid-Open No. 5-50109 has been proposed as a rolling mill capable of preventing deterioration of the material surface properties and using a small-diameter work roll.

[0003] The rolling mill described in Japanese Patent Application Laid-Open No. 5-50109 has a plurality of rows of support rolls installed from the entrance and exit sides on the outer work roll body through which the maximum sheet width passes, and the outermost one of the support rolls. The roll is accompanied by a cylinder that gives the work roll horizontal bending. In this rolling mill, horizontal deflection prevention is performed by adjusting the offset amount of the work roll by moving the work roll so that the horizontal force acting on the work roll during rolling is reduced, and detecting the horizontal deflection of the work roll and setting this in advance. This is done by controlling the cylinder that gives the horizontal bending so that it is within the value.

[0004]

However, the above prior art has the following problems. That is, in the above-described prior art, the offset amount of the work roll is adjusted to reduce the horizontal force acting on the work roll. In order to dynamically balance the tangential force generated from the roll and the component force of the rolling load, the work roll must always be offset to the exit side in the pass direction. For this reason, when the rolling mill is applied to a reversing type rolling mill, it is necessary to open the gap between the upper and lower work rolls at the time of changing the pass direction and greatly change the offset position of the work rolls, and to change the horizontal position of the work rolls. The position of the work roll is shifted from the point where the rolled material bites due to the change of the rolled material.Therefore, it is necessary to send the rolled material in the pass direction by the amount that the offset position of the work roll is changed. In short, there is a problem that productivity is reduced.

It is an object of the present invention to provide a reversible rolling mill and a rolling method that can switch the direction of a pass quickly and improve productivity.

[0006]

To achieve the above object, the present invention employs the following constitution. That is, a pair of upper and lower work rolls, at least a pair of upper and lower support rolls for supporting the pair of upper and lower work rolls from above and below, and by driving the pair of upper and lower support rolls, In a reversing type rolling mill that transmits a driving torque and reduces the thickness of a rolled material by the pair of upper and lower work rolls, each is provided on a rolled material inlet / outlet side of the pair of upper and lower work rolls, and has a maximum sheet width of the rolled material. At least a pair of front and rear support rollers that support each end of the outer work roll body from both sides in the horizontal direction, and the offset position of the pair of upper and lower support rolls is inserted into the upper and lower work rolls in the pass direction when switching the pass direction. And offset position changing means for changing the pair of upper and lower support rolls by the offset position changing means. By changing the position, a configuration for switching a path egress direction side with respect to the pair of upper and lower work the upper and lower support rolls offset position of the roll.

In the above rolling mill, preferably, the unbalance amount of the horizontal force applied to the pair of upper and lower work rolls during rolling is detected, and the pair of the upper and lower work rolls is adjusted so that the unbalance amount of the horizontal force is within a predetermined value. There is further provided an offset amount adjusting means for adjusting the offset amount of the roll.

Preferably, the offset position means is means for changing the offset position of the pair of upper and lower support rolls by moving the pair of upper and lower support rolls by a fixed amount at the time of switching the path direction. The adjusting means is means for adjusting the offset amount of the pair of upper and lower work rolls by moving the pair of upper and lower work rolls by a required amount during rolling.

More preferably, the pair of front and rear support rollers are provided on a first roller provided on one of the pass direction entrance side and the pass direction exit side, and on the other of the pass direction entrance side and the pass direction exit side. A second roller provided, wherein the offset amount adjusting means supports the first roller and positions the pair of upper and lower work rolls;
Means for supporting the rollers and pressing the pair of upper and lower work rolls.

Preferably, a horizontal deflection of the pair of upper and lower work rolls is detected during rolling, and a horizontal reverse bending force is applied to the pair of upper and lower work rolls so that the horizontal deflection is within a preset value. The apparatus further includes horizontal deflection control means.

In this case, for example, the horizontal deflection control means is a means for applying a horizontal reverse bending force to the roll neck bearings of the pair of upper and lower work rolls.

Further, the horizontal deflection control means may be means for applying a horizontal reverse bending force to the work roll body outside the pair of front and rear support rollers in the plate width direction.

Further, in order to achieve the above object, the present invention employs the following constitution. That is, a pair of upper and lower work rolls, at least a pair of upper and lower support rolls for supporting the pair of upper and lower work rolls from above and below, and by driving the pair of upper and lower support rolls, In a rolling method of a reversing type rolling mill for transmitting a driving torque and reducing the thickness of a rolled material by the pair of upper and lower work rolls, each end of a work roll body portion outside the maximum plate width of the rolled material at the time of rolling. Rolling while supporting from both sides in the horizontal direction by a pair of front and rear support rollers, by changing the offset position of the pair of upper and lower support rolls to the pair of upper and lower work rolls in the pass direction when switching the pass direction, the vertical The offset position of the pair of work rolls is switched to the path direction exit side with respect to the pair of upper and lower support rolls.

In the above-mentioned rolling method, preferably, the offset position of the pair of upper and lower support rolls is changed by moving the pair of upper and lower support rolls by a fixed amount when the pass direction is switched, and the pair of upper and lower support rolls is rolled during rolling. The offset amount of the pair of upper and lower work rolls is adjusted by moving the required amount.

[0015]

In the present invention constructed as described above, when the path direction is switched, the offset position of the pair of upper and lower support rolls is switched by the offset position changing means so as to be on the entrance side in the path direction with respect to the pair of upper and lower work rolls. Thereby, the offset position of the pair of upper and lower work rolls is switched without opening the roll gap between the pair of upper and lower work rolls and without the pair of upper and lower work rolls running on the unrolled portion of the rolled material, thereby shortening the path direction switching. Do it in time and increase productivity. At this time, if the pair of upper and lower support rolls is moved while applying a rolling load, the pair of upper and lower support rolls move while rotating with respect to the pair of upper and lower work rolls. There is no slip between them and the offset position can be changed without damaging the rolls.

Further, during rolling, the offset amount adjusting means adjusts the offset amount of the pair of upper and lower work rolls so that the unbalance amount of the horizontal force applied to the pair of upper and lower work rolls is within a preset value. The horizontal deflection of the work roll can be reduced to zero.

Further, during rolling, the horizontal deflection control means applies a horizontal reverse bending force to the pair of upper and lower work rolls so that the horizontal deflection of the pair of upper and lower work rolls is within a preset value. The horizontal deflection of the pair of work rolls can be reduced to zero. At this time, the horizontal deflection of the pair of upper and lower work rolls can be quickly reduced to zero, and the rolling can be stably performed by using the offset amount adjuster together with the adjustment of the offset amount of the pair of upper and lower work rolls.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment of the present invention will be described with reference to FIGS. In FIG. 1, the rolling mill of the present embodiment is a reversal type six-high rolling mill, and a pair of upper and lower work rolls 1 and 1a.
And a pair of upper and lower intermediate rolls 2 and 2a that support the work rolls 1 and 1a from above and below, and a pair of upper and lower reinforcing rolls 3 and 3a that support the intermediate rolls 2 and 2a from above and below. Since the diameter of the work rolls 1 and 1a is too small,
Since it is not possible to directly apply the torque required for rolling by directly driving the work rolls 1 and 1a, the drive torque is transmitted to the work rolls 1 and 1a by driving the intermediate rolls 2 and 2a. The thickness of the rolled material 14 is reduced.

FIG. 2 shows one end of the upper work roll 1 on the six-ply rolling mill shown in FIG. Upper work roll 1
The same applies to the other end side and the lower work roll 1a side. 2, the upper work roll 1 is supported from both sides in the horizontal direction by a pair of front and rear support rollers 4, 5 at the end of the roll body outside the maximum plate width of the rolled material 14. 1 is provided on the rolled material 14 exit side of the upper work roll 1 as viewed in the direction, and is supported by a screw type positioning device 6 via a load cell 7, and the support roller 5 is located on the rolled material 14 entrance side in the rolling direction in FIG. And supported by a support roll pressing cylinder 10. The load cell 7 detects a horizontal force Fh in the pass direction applied to the upper work roll 1 described later, and the positioning device 6 detects the horizontal force Fh.
The upper work roll 1 is positioned so that h is within a preset value, and the support roll pressing cylinder 10 presses the upper work roll 1. The support roller 4 is connected to a frame 28, and a gap sensor 26 for detecting the horizontal deflection of the upper work roll 1 is attached to the frame 28.

An end of the upper work roll 1 is supported by a work roll bearing box 19, and a project block 17 is provided on both sides of the work roll bearing box 19 with a predetermined amount of clearance. Work roll horizontal deflection control cylinders 11 and 12 for applying a horizontal reverse bending force to the work roll bearing box 19 so that the horizontal deflection of the upper work roll 1 are within a preset value are provided. A thrust bearing 13 is disposed outside the work roll bearing box 19 at the end of the upper work roll 1, and a thrust bearing positioning device 16 and a keeper plate 15 are attached to the thrust bearing 13. The thrust bearing positioning device 16 is arranged so that the thrust bearing 13 always coincides with the center of the upper work roll 1 when the upper work roll 1 is positioned by the positioning device 6.
Adjust the position of.

Returning to FIG. 1, the intermediate rolls 2, 2a are supported by the intermediate roll bearing boxes 18, 18a, and have a predetermined amount of clearance between the intermediate roll bearing boxes 18, 18a and the project blocks 17, 17a. . In the project blocks 17, 17a, switching cylinders 8, 8a, which change the offset position of the intermediate rolls 2, 2a so as to be on the entrance side in the path direction with respect to the work rolls 1, 1a by moving the intermediate roll bearing boxes 18, 18a. 9, 9a are provided. In the drawing, the constituent members on the lower work roll 1a side are denoted by the same reference numerals as those related to the upper work roll 1 with a suffix a.

FIG. 3 shows the balance of the forces acting on the work rolls 1 and 1a when rolling is performed using a rolling mill having the small-diameter work rolls 1 and 1a that cannot be directly driven as described above. When the rolled material 14 is rolled in the direction of arrow A, the work rolls 1 and 1a have a rolling load P, a tangential force F for applying torque to the work rolls 1 and 1a,
, A front tension Tf and a rear tension Tb applied thereto.
At this time, the total of the horizontal forces Fh that give the work rolls 1 and 1a a deflection in the horizontal direction is represented by Fh = Psin θ−Fcos θ + Tf−Tb (1) At this time, in particular, in a rolling mill having small-diameter work rolls 1 and 1a, the rigidity of the work rolls 1 and 1a is small, so that the value of θ must be set so that the horizontal force Fh ≒ 0. Here, the value of θ is sin θ = δ / (r1 + r2) (2) where r1: a radius of the work rolls 1 and 1a, and r2 is a geometric value determined by a radius of the intermediate rolls 2 and 2a. At this time, the value of δ is the offset amount, and by adjusting this offset amount δ, it is possible to realize the state of the horizontal force Fh ≒ 0.

Next, the rolling method of the present embodiment in which the pass direction is switched using the rolling mill configured as described above will be described with reference to FIG. In FIG. 4, the path direction is indicated by a solid arrow A.
When switching from to the dashed arrow B, first, the power supply circuit (not shown) of the main motor of the rolling mill is turned off while the rolling load is applied, and the intermediate rolls 2 and 2a, which are the driving rolls, are not driven (free rotation is possible). And unwinding and winding device 4
The brakes 43A, 43B attached to the drive motors 42A, 42B of 1A, 41B are operated to fix the rolled material 14. Also, the rolling load is kept applied. At this time,
Since the rolled material 14 does not move and a rolling load is applied to the work rolls 1 and 1a, the work rolls 1 and 1a do not rotate.

Next, while the rolling load is applied, the offset switching cylinders 8, 8a are pulled, the offset switching cylinders 9, 9a are extruded, and the intermediate roll bearing boxes 18, 18a are moved, so that the center position of the intermediate rolls 2, 2a becomes the work roll. The offset position of the intermediate rolls 2 and 2a is changed from the solid line C1 to the dashed line C2 so that the offset position of the intermediate rolls 2 and 2a is δ * with respect to the center position of 1,1a. At this time, the intermediate rolls 2 and 2a rotate (revolve) around their own axes while rotating (revolving) around the work rolls 1 and 1a and move by a fixed amount 2δ * as described below. The reinforcing rolls 3 and 3a rotate as the intermediate rolls 2 and 2a rotate.

The rolled material 14 is fixed by the brakes 43A and 43B and does not move.

Since the rolled material 14 does not move and a rolling load is applied, the work rolls 1 and 1a do not rotate.

When the intermediate roll bearing boxes 18 and 18a are moved, the work rolls 1 and 1a do not rotate and a rolling load is applied.
2a revolves around its own axis (Y in the figure) and moves while revolving around the work rolls 1 and 1a (X in the figure).

When the intermediate rolls 2 and 2a rotate as described above in a state where a rolling load is applied, the freely rotatable reinforcing rolls 3 and 3a rotate along with the rotation of the intermediate rolls 2 and 2a (Z in the figure). ).

As described above, the intermediate rolls 2 and 2a move while rotating with respect to the work rolls 1 and 1a and the reinforcing rolls 3 and 3a, and thereby the gap between the intermediate rolls 2 and 2a and the work rolls 1 and 1a is increased. And no slip occurs between the intermediate rolls 2, 2a and the reinforcing rolls 3, 3a,
The offset position can be changed without damaging the roll.

Next, the gap between the work rolls 1 and 1a is changed to the set value of the next pass, and rolling is started. However, at this time, since the moving amount of the intermediate rolls 2 and 2a is fixed to 2δ * as described above, the horizontal force Fh ≒ 0 is not always obtained.
The horizontal force Fh is small, and the horizontal force Fh 制 御 0 can be set by performing the following control.

That is, at the time of rolling, the horizontal deflection of the work rolls 1 and 1a generated due to the imbalance of the horizontal force Fh is detected by the gap sensor 26 and sent to a computer (not shown). The horizontal deflection control cylinders 11 and 12 are controlled.
At the same time, the unbalance amount of the horizontal force Fh is
And is sent to the computer, which calculates the horizontal force Fh
Calculate the offset amount that makes ≒ 0, and work rolls 1, 1a
The positioning device 6 is controlled so that the offset amount is finely adjusted to a position where the horizontal force Fh ≒ 0 finally. At this time, the horizontal force Fh can be made zero and the horizontal deflection can be made zero only by the control by the positioning device 6. However, since the control by the positioning device 6 takes time to stabilize, the work roll having a quick effect can be obtained. By using it together with the control by the horizontal deflection control cylinders 11 and 12, the horizontal deflection can be quickly reduced to zero and stable rolling can be performed.

Since the present embodiment is configured as described above, the following effects can be obtained. First, as a comparative example, a case where the offset position of the work roll is changed by moving only the work roll as in the related art will be described with reference to FIG. In FIG. 5, when the path direction is switched from the direction A to the direction B, the center positions of the work rolls 51 and 51a are set to the intermediate rolls 52 and 5 respectively.
It is necessary to move the work rolls 51 and 51a from the solid line D1 to the dotted line D2 so as to be on the exit side in the path direction with respect to the center position of 2a. At this time, in order to move the work rolls 51 and 51a without opening the gap, the work rolls 51 and 51a must ride on the hatched portion S where rolling is not yet performed, and the work rolls 51 and 51a are moved to the position indicated by the dotted line D2. In order to move 51a, it is necessary to perform while rolling the rolled material 54 with an enormous force, which is difficult for the small-sized work rolls 51 and 51a having small rigidity. Therefore, when the path is switched, the gap between the work rolls 51 and 51a is opened, the work rolls 51 and 51a are moved to the position indicated by the dotted line D2, and the work rolls 51 and 51a do not ride on the unrolled portion S of the rolled material 54. In addition, the rolled material 54 must also move in the direction of the dotted line B, and it takes a long time to switch the path direction,
Productivity decreases.

On the other hand, in this embodiment, as shown in FIG. 6, when the pass direction is switched from the direction A to the direction B, the center positions of the intermediate rolls 2 and 2a are set to the work rolls 1 and 1.
The intermediate rolls 2 and 2a are moved from the solid line C1 to the broken line C2 by a fixed amount
δ *, the offset position of the work rolls 1 and 1a is changed without opening the gap between the work rolls 1 and 1a and without running the work rolls 1 and 1a on the unrolled portion of the rolled material 14. The direction can be switched in a short time, and the production of hard and ultra-thin materials can be performed efficiently. At this time, since the pass direction is switched while the rolling load is applied, the intermediate rolls 2 and 2a are switched to the work rolls 1 and 1.
a and rotating with respect to the reinforcing rolls 3 and 3a, and a slip occurs between the intermediate rolls 2 and 2a and the work rolls 1 and 1a and between the intermediate rolls 2 and 2a and the reinforcing rolls 3 and 3a. The offset position can be changed without damaging the roll. Also,
During rolling, work roll horizontal deflection control cylinder 11,
12, the horizontal deflection of the work rolls 1 and 1a is controlled to be zero, and the offset amount of the work rolls 1 and 1a is finely adjusted by the positioning device 6 so that the horizontal force Fh applied to the work rolls 1 and 1a is zero. Therefore, the horizontal deflection of the work rolls 1 and 1a can be quickly reduced to zero, and stable rolling can be performed.

A second embodiment of the present invention will be described with reference to FIG. The present embodiment is a rolling mill having the same configuration as that of the first embodiment shown in FIG. 1 and provided with means for applying a horizontal reverse bending force to the ends of the roll body portions of the work rolls 1 and 1a. It is. In the drawing, members that are the same as the members illustrated in FIG. 2 are given the same reference numerals, and descriptions thereof will be omitted.

In FIG. 7, the support rollers 4 and 5 are attached to rigid beams 22 and 23, respectively, and the upper work roll 1 is mounted on the body of the upper work roll 1 outside the support rollers 4 and 5 in the plate width direction. Support rollers 20 and 21 for supporting in the horizontal direction are arranged. These support rollers 2
Reference numerals 0 and 21 denote work roll horizontal deflection control cylinders 24 and 24 that apply a horizontal reverse bending force to the body of the upper work roll 1.
25 presses against the upper work roll 1.

In this embodiment, when the pass direction is switched, the horizontal deflection of the work rolls 1 and 1a caused by the imbalance of the horizontal force Fh during rolling is detected by the gap sensor 26 and sent to a computer (not shown). The computer controls the work roll horizontal deflection control cylinders 24 and 25 so that the horizontal deflection becomes zero. Otherwise, it is completely the same as the first embodiment.

In this embodiment, as in the first embodiment, the pass direction can be switched in a short time, the production of hard and ultra-thin materials can be performed efficiently, and the work rolls 1 and 1a can be quickly produced. Can be reduced to zero and stable rolling can be performed.

In the above embodiment, the working roll horizontal deflection control cylinders 11, 12;
25, the horizontal deflection of the work rolls 1 and 1a is controlled to be zero, and the offset amount of the work rolls 1 and 1a is finely adjusted by the positioning device 6 so that the horizontal force Fh ≒ 0 applied to the work rolls 1 and 1a. However, the invention is not limited to this, and the work roll horizontal deflection control cylinder 1
1, 12; only the control of the horizontal deflection of the work rolls 1 and 1a by 24 and 25, or only the adjustment of the offset amount of the work rolls 1 and 1a by the positioning device 6, may be performed. , 1a can be reduced to zero.

In the above embodiment, the offset positions of the intermediate rolls 2 and 2a are shifted by a fixed amount δ * with respect to the work rolls 1 and 1a by the offset switching cylinders 8, 8a, 9 and 9a when the pass direction is switched. Of the work roll horizontal deflection control at the time of rolling,
5 controls the horizontal deflection of the work rolls 1 and 1a and adjusts the offset amount of the work rolls 1 and 1a by the positioning device 6. However, if the roll diameter of the work rolls 1 and 1a is somewhat large, the intermediate rolls 2 and 1 are used. Since the horizontal deflection of the work rolls 1 and 1a can be reduced to zero only by changing the offset position 2a, in this case, the work roll horizontal deflection control cylinders 11 and 12;
The positioning device 5 and the positioning device 6 may not be provided.

In the above embodiment, a six-roll mill was described. However, the present invention is not limited to this, and a four-roll mill without an intermediate roll may also be used to adjust the offset position of the reinforcing roll when the pass direction is switched. The work rolls 1 and 1a are changed so that the rolls are on the entrance side in the pass direction.
The present invention can be applied by switching the offset position.

[0041]

According to the present invention, the path direction can be switched quickly in almost the same time as a rolling mill having a normal large-diameter work roll, and the production of hard and ultra-thin materials can be performed efficiently. Can be.

[Brief description of the drawings]

FIG. 1 is a sectional view of a rolling mill according to a first embodiment of the present invention.

FIG. 2 is a plan view of an upper work roll section of the rolling mill shown in FIG.

FIG. 3 is a diagram showing a force acting on a work roll in a rolling mill that drives an intermediate roll.

FIG. 4 is a diagram illustrating an operation of each roll at the time of offset switching according to the present embodiment.

FIG. 5 is a diagram illustrating a state of path direction switching when only a work roll is moved and offset is performed.

FIG. 6 is a diagram illustrating a state of path direction switching according to the present embodiment.

FIG. 7 is a plan view of an upper working roll section of a rolling mill according to a second embodiment of the present invention.

[Explanation of symbols]

 1, 1a Work roll 2, 2a Intermediate roll 3, 3a Reinforcement roll 4, 4a, 5, 5a Support roller 6, 6a Positioning device 8, 8a, 9, 9a Intermediate roll offset cylinder 10, 10a Support roll pressing cylinder 11, 12 Work roll horizontal deflection control cylinder 14 Rolled material 19 Work roll bearing box 20, 21 Support roller 24, 25 Work roll horizontal deflection control cylinder

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-148002 (JP, A) JP-A-56-56708 (JP, A) JP-A-60-18206 (JP, A) 50109 (JP, A) JP-A-7-80509 (JP, A) JP-A-58-43804 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B21B 13/14 B21B 1 / 32 B21B 29/00 B21B 31/20

Claims (4)

(57) [Claims] 1. A pair of upper and lower work rolls, and at least a pair of upper and lower support rolls supporting the pair of upper and lower work rolls from above and below, and the pair of upper and lower support rolls is driven by driving the pair of upper and lower support rolls. A reversible rolling mill that transmits a driving torque to a work roll and reduces the thickness of a rolled material by the pair of upper and lower work rolls. At least a pair of front and rear support rollers that support each end of the work roll body portion outside the plate width from both sides in the horizontal direction, and the offset position of the pair of upper and lower support rolls when switching the path direction with respect to the pair of upper and lower work rolls. Offset position changing means for changing to the entrance side in the pass direction, wherein the offset position changing means turns off the pair of upper and lower support rolls. Tsu by changing the bets position, rolling mill, characterized by switching the offset position of the pair of upper and lower work rolls to the delivery side of the path direction with respect to the pair of upper and lower supporting rolls. 2. The rolling mill according to claim 1, wherein an unbalance amount of a horizontal force applied to said pair of upper and lower work rolls during rolling is detected, and said vertical force is adjusted so as to be within a predetermined value. A rolling mill further comprising an offset adjusting means for adjusting an offset between a pair of work rolls. 3. A pair of upper and lower work rolls, and at least a pair of upper and lower support rolls for supporting the pair of upper and lower work rolls from above and below, and the pair of upper and lower support rolls is driven by driving the pair of upper and lower support rolls. In a rolling method of a reversing type rolling mill for transmitting a driving torque to a work roll and reducing the thickness of a rolled material by the pair of upper and lower work rolls, each of the work roll body portions outside the maximum sheet width of the rolled material at the time of rolling. Rolling while supporting the end portion from both sides in the horizontal direction with a pair of front and rear support rollers, by changing the offset position of the pair of upper and lower support rolls to the pair of upper and lower work rolls in the pass direction when switching the pass direction. The offset position of the pair of upper and lower work rolls is switched to the path direction exit side with respect to the pair of upper and lower support rolls. Method. 4. The rolling method according to claim 3 , wherein the pair of upper and lower support rolls is moved by a fixed amount at the time of switching the pass direction, thereby changing the offset position of the pair of upper and lower support rolls. A rolling method comprising: adjusting the offset amount of the pair of upper and lower work rolls by moving the work rolls by a required amount.