JP3121911B2 - Four-high 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 four-high rolling mill and a rolling method for a sheet material, and more particularly, to controlling a sheet crown by fixing a pair of upper and lower reinforcing rolls and moving only a pair of upper and lower work rolls with each other. The present invention relates to a rolling mill and a rolling method.

[0002]

2. Description of the Related Art Conventionally, a roll-cross type four-high rolling mill which has been put to practical use is disclosed in Mitsubishi Heavy Industries Technical Report Vol. 21, NO.
6 (1984). 61-P. As described in 67, the roll set of the pair of the upper work roll and the upper reinforcement roll and the roll set of the pair of the lower work roll and the lower reinforcement roll are integrally formed, and the axes of the roll sets of each pair are mutually reciprocated in a horizontal plane. Had to be crossed.

[0003] However, in this pair-cross type rolling mill in which the work roll and the reinforcing roll cross integrally, the slip between the reinforcing roll and the work roll and the generation of thrust force can be suppressed, but the metal of the reinforcing roll directly receiving the rolling load can be suppressed. Since the center of the chock is displaced from the center of the screw, a rotational moment acts on the metal chock, causing a local load on the sliding surface with the mill stand, hindering the smooth operation of the rolling operation and reducing the wear on the sliding surface. Improve. In order to prevent this, an equalizer beam having a large rigidity as described in, for example, JP-A-56-131004 and JP-A-56-131005, or as described in JP-A-57-4307. A thrust beam is provided on the vehicle to balance the moment between the drive side and the operation side. However, this method requires a beam having high rigidity, and inevitably necessitates a complicated and large-sized rolling mill.

On the other hand, there is a roll cross rolling mill which does not require the provision of the above-mentioned large rigid beam, in which a reinforcing roll is not crossed and only a work roll is crossed. This trial is earlier than a pair cross, for example, Japanese Patent Laid-Open No. 47-27159. However, practical application has not been successful to date.

[0005]

The following two reasons why the rolling mill in which only the work rolls crossed were not put to practical use were as follows.
One problem could not be solved.

First, when a work roll is crossed with a reinforcing roll, a huge thrust force (thrust) acts in opposite directions in the axial direction of both rolls. Although this value varies depending on the cross angle, it reaches about 30% of the rolling load, and it is not impossible for a large-diameter reinforcing roll thrust bearing to withstand it. Difficult for rolls.

The next problem is roll wear due to relative slip between the reinforcing roll and the work roll. The work roll is replaced in a few hours because of the wear by the rolled material that is much larger than the wear due to this cause, so it does not matter.
Reinforcement rolls are replaced every 10 to 20 days, and the replacement takes a long time. Therefore, increasing the frequency of roll replacement due to rapid roll abrasion greatly reduces productivity.

The applicant has filed Japanese Patent Application No. 3-66007 to solve the above two problems. The purpose of this application is
It is an object of the present invention to provide a rolling mill in which work rolls cross each other, which have excellent ability to control a strip crown of a rolled material and can reduce a thrust force acting on the work rolls with a simple configuration. Specifically, the reinforcing roll of the rolling mill is configured such that its roll axis does not incline in a horizontal plane, and the upper and lower work rolls, while the axis of the work roll intersects with the axis of the reinforcing roll, Lubrication for supplying a lubricant between the work roll and the reinforcing roll, wherein the work rolls are configured so that the roll axis can be inclined with respect to the reinforcing roll in a horizontal plane so as to intersect the roll axes with each other. A thrust force and roll abrasion acting on the work rolls due to the action of this lubricant can be reduced to such a level that there is no practical problem even if the work rolls cross. The ability to fully demonstrate the capability and the need for a large rigid beam were eliminated, making it possible to realize a compact rolling mill in which work rolls crossed. The application proposes application of the cross rolling mill to hot rolling.

In a rolling mill in which only the work rolls are crossed, the cross angle needs to be variable from about 0 ° to about 1 ° due to its crown control ability. Therefore, at this time, the axis of the reinforcing roll is not inclined,
That is, since it is perpendicular to the rolling pass, the axis of the work roll is necessarily 0 ° to 1 ° with respect to the axis of the reinforcing roll.
Will change up to ゜. In the hot rolling mill, the generation of the thrust force and the abrasion of the rolls can be suppressed by supplying the lubricant between the rolls.

However, when the above work roll cloth rolling mill is further applied to a non-ferrous metal hot rolling mill or a general cold rolling mill in order to utilize crown control, the following problems occur.

That is, in a hot rolling mill for a non-ferrous metal, for example, aluminum, aluminum is coated on the surface of the work roll. At this time, if the cross angle between the work roll and the reinforcing roll is large, the coating may peel off or become uneven. Distribution can significantly alter the surface quality of the rolled material.

Further, in a general cold rolling mill, not only the wear of the roll is reduced, but also the surface of the roll must be kept as constant as possible. However, when the work roll and the reinforcing roll are crossed greatly, the amount of wear of the roll can be reduced by the roll coolant, but the roughness of the roll surface changes drastically, and the surface quality of the rolled material can fluctuate significantly. There is. In particular, when the surface roughness of the work roll is reduced, slip may occur between the work roll and the rolled material. In such a case, rolling cannot be performed, so that the work roll must be replaced at an early stage and productivity is impaired.

SUMMARY OF THE INVENTION An object of the present invention is to provide a four-high rolling mill in which a reinforcing roll is fixed and a work roll alone is cross-moved with each other to control a sheet crown. And to provide a four-high rolling mill and a rolling method capable of suppressing a change in the surface quality of a rolled material.

[0014]

In order to achieve the above object, according to the present invention, there is provided a pair of upper and lower work rolls, and a pair of upper and lower reinforcing rolls respectively supporting these work rolls. In a four-high rolling mill in which a pair of upper and lower work rolls are fixed and a pair of upper and lower work rolls are cross-moved with each other to control a sheet crown, the upper and lower reinforcing rolls are respectively set so that their axes are perpendicular to the rolling pass direction. A four-high rolling mill, wherein the four-high rolling mill is arranged so as to be inclined in the same direction as the upper and lower work rolls and in the opposite directions to each other with respect to a basic line.

[0015] In the four-high rolling mill, preferably, an operating side and a driving side rolling-down device for applying a rolling force to the upper and lower reinforcing rolls are provided so that a straight line connecting their centers is perpendicular to a rolling path direction. To be inclined in the same direction as the upper and lower reinforcing rolls. In this case, preferably, an axis of the upper and lower reinforcing rolls and a straight line connecting the centers of the operating side and the driving side pressing-down devices are inclined at substantially the same angle with respect to the rolling pass direction.

Preferably, a cross device is provided for tilting the upper and lower work rolls to be cross-moved in opposite directions about the axis of the upper and lower reinforcement rolls.

[0017] Preferably, the operation side and drive side pressure reduction devices include a hydraulic jack and / or a pressure screw. The operation side and drive side screw down devices are configured by combining a hydraulic jack and a screw down screw, the center line of the operation side and the drive side screw down screw is perpendicular to the rolling pass direction, and the center line of the operation side and the drive side hydraulic jack. May be inclined with respect to a line perpendicular to the rolling pass direction. In this case, it is preferable to provide a means for holding the hydraulic jack so that the moment due to the unbalanced load applied to the hydraulic jack is not transmitted to the screw.

According to the present invention, in order to achieve the above object, according to the present invention, a pair of upper and lower reinforcing rolls of a four-high rolling mill are fixed, and only a pair of upper and lower working rolls are cross-moved with each other to control a sheet crown. In the rolling method, the axes of the upper and lower reinforcing rolls are inclined in the same direction as the upper and lower work rolls and in directions opposite to each other with respect to a line perpendicular to the rolling pass direction, and the cross angle to be controlled is set to the reinforcing roll. The rolling method is characterized in that the rolling is performed in the plus and minus directions around the axis of the rolling. In this case, preferably, when changing rolls, the cross angle is set to zero with respect to a line perpendicular to the rolling pass direction.

[0019]

In the present invention constructed as described above, the reinforcing roll is fixed and only the work roll is cross-moved.
The angle between the work roll and the reinforcing roll is always kept small by tilting the axis of the reinforcing roll in the opposite direction to the line perpendicular to the rolling pass direction in accordance with the inclination direction of the work roll in the high-speed rolling mill. Therefore, the relative slip between the rolls is also small, and the variation in the surface properties and the roughness of the rolls is suppressed to a small level.

Further, by allocating the cross angle to be controlled to plus or minus around the axis of the reinforcing roll, a sufficiently large sheet crown control function can be obtained even with a small change of the cross angle, and the work roll and the work roll can be controlled while maintaining the sheet crown control function. The angle formed by the reinforcing roll can be further reduced. Further, in this case, the amount of change of the plate crown with respect to the cross angle to be controlled becomes substantially linear, and the control becomes easy.

Further, by inclining a straight line connecting the center of the operating-side pressing device and the center of the driving-side pressing device with respect to a line perpendicular to the direction of the rolling pass, the center of the bearing box of the reinforcing roll and the center of the pressing device. Is small, the rotational moment generated in the bearing box of the reinforcing roll is reduced, and the equalizer beam becomes unnecessary.

Further, as described in JP-A-60-83703, in the hot rolling of iron, when the intersection angle 2θ of the upper and lower work rolls is in the range of 0 to 0.5 ° and 1.0 ° or more,
Although it is known that the fracture surface transition temperature changes, in the present invention, the cross angle controlled around a straight line connecting the center of the operating-side pressing device and the center of the driving-side pressing device is divided into plus and minus. Therefore, the intersection angle 2θ is always 2 ° or more, so that the fracture surface transition temperature does not change and the low-temperature toughness value is improved. Further, the fracture surface transition temperature has a constant value without variation, and uniform quality can be secured.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. A first embodiment of the present invention will be described with reference to FIGS. 1 and 2, the cross type four-high rolling mill of the present embodiment is provided at upper and lower work rolls 1 and 2, upper and lower reinforcing rolls 3 and 4 supporting the upper and lower work rolls, and at both ends of each work roll, Upper bearing boxes 5a, 5b and lower bearing boxes 6a, 6b (only one shown) for rotatably supporting the work roll.
And upper bearing boxes 7a and 7b provided at both ends of each reinforcing roll and rotatably supporting the reinforcing rolls (only one is shown).
And lower bearing boxes 8a and 8b (only one is shown). Upper bearing box 5a, 5b and lower bearing box 6 of the work roll
a and 6b are a pair of upper and lower work rolls 1 and
2 are movably attached to the operation side and drive side mill housings 9a and 9b so as to cross-move each other.
Upper bearing boxes 7a, 7b and lower bearing boxes 8a, 8 of reinforcing rolls
b is fixedly installed with respect to the operation side and drive side mill housings 9a and 9b so that only the work roll moves crosswise. However, the axes 18, 1 of the reinforcing rolls 3, 4
No. 9 has a tilt angle of 1.2 ° in the opposite direction to the line 17 perpendicular to the rolling pass direction.

On the upper side of the operation side mill housing 9a and the drive side mill housing 9b, a screw down screw 10a and a screw down nut 11a (drive side not shown) are provided as a screw down device or a pass line height adjusting device. These screw-down screws are arranged such that a straight line connecting the centers 12a and 12b is inclined at an angle of 1.2 ° in the same direction as the axis 18 of the upper reinforcing roll 3 with respect to a line 17 perpendicular to the rolling pass direction. I have. Similarly, a straight line connecting the center 13a (only one is shown) of the bearing box receiving surface of the working side of the lower reinforcing roll 4 that receives the bearing boxes 8a and 8b and the drive side support 50a (only one is shown) is perpendicular to the rolling pass direction. It is inclined at an angle of 1.2 ° in the same direction as the axis 19 of the lower reinforcing roll 4 with respect to the line 17.

Although not shown, when a hydraulic jack is installed below the lower bearing box, a straight line connecting the centers of the hydraulic jacks is also a line 1 perpendicular to the rolling pass direction.
7 is arranged at an angle of 1.2 ° in the same direction as the lower reinforcing roll 4.

The cross angle of the upper work roll 1 is determined by the window 16 of the operation side and drive side mill housings 9a and 9b.
a, hydraulic cylinders 20a, 21a provided in 16b
, And 20b, 21b. Although not shown, the cross angle of the lower work roll 2 is also controlled by crossing the work rolls with a similar cloth device.
Here, the upper and lower work rolls 1 and 2 are, as shown in FIG.
The rolls are tilted in opposite directions around the axes 18 and 19 of the 1.2 ° reinforcing roll in the range of about ± 0.2 °, and the cross angle is controlled. That is, assuming that the cross angle is θ and the inclination angles of the axes 18 and 19 of the reinforcing rolls are θ ₀ , the control range of the cross angle θ is ₀ to θ _{max with} respect to the line 17 perpendicular to the rolling pass direction as in the related art. Instead, the inclination angle θ ₀ of the axes 18 and 19 of the reinforcing rolls is set as the central angle and θ ₀ −Δθ−
It is controlled in the range of θ ₀ + Δθ.

The axial directions of the upper and lower work roll bearing boxes 5a, 5a are keeper plates 22a, 22b and 23a, 23b.
, And these keeper plates have arcuate surfaces 24a and 24b that allow the bearing box to tilt.

When the rolls are changed, the upper and lower work rolls 1 and 2 are pulled out from the mill housings 9a and 9b for replacement with the inclination angle of the work rolls 1 and 2 being 0 °, that is, the cross angle with respect to the rolling pass direction being zero. Although not shown, the upper and lower work rolls 1 and 2 are driven by a motor via a universal joint and a speed reducer as in a general rolling mill.

The upper and lower bearing boxes 7a, 7b and 8a, 8b of the reinforcing roll are fixedly attached to the operation side and drive side mill housings 9a, 9b as described above. Hydraulic cylinders for tilting these bearing boxes 8a, 8b may be provided on condition that the reinforcing rolls 3, 4 are kept fixed when the cloths are moved. In this case, the reinforcing rolls 3, 4 are also replaced with rolls. At the time, it can be replaced by being pulled out from the mill housings 9a and 9b with the inclination angle set to 0 °.

The operation of the four-high rolling mill of the present embodiment configured as described above will be described. First, in the conventional work roll cross type four-high rolling mill, the axes of the upper and lower reinforcing rolls are arranged so as to be perpendicular to the rolling pass direction, and the center of the screw is aligned with the center of the bearing box of the reinforcing roll. I have.

In such a conventional cross-type four-high rolling mill, when the work rolls 1 and 2 are crossed by θ each in the vertical direction opposite to the center O of the roll body,
The work rolls 1 and 2 also cross the reinforcing rolls 3 and 4 by θ.

On the other hand, in the present embodiment, the axes of the reinforcing rolls 3 and 4 are inclined in directions opposite to each other with respect to a line perpendicular to the rolling pass direction in the same direction as the inclination of the work rolls 1 and 2. Basically, with this configuration, the work rolls 1,
The angle between 2 and the axes of the reinforcing rolls 3 and 4 is always kept small, so that the relative slip between the rolls is also small, and the variation in the surface properties and ancestry of the rolls can be kept small.

In the conventional cross-type four-high rolling mill, when the work rolls 1 and 2 are crossed by θ in the up and down directions about the center O of the roll body, respectively, the roll center O and the b center therefrom The difference in the gap between the upper and lower rolls at points separated in the axial direction, that is, the roll gap _Cb is approximately expressed by the following equation.

[0034]

C _b = (b ² / R) θ ² (1 + ε) (1) where R is the radius of the work roll. Ε is the ratio of the gap between the work roll and the reinforcing roll that affects the upper and lower work rolls under the rolling load, but is usually smaller than 1 and is omitted here for simplicity.

Therefore, the change amount C _bmax of the roll gap obtained by changing θ from zero to θ _max is:
C _bmax = a _{^{(b 2 / R) θ max}} 2.

Next, in this embodiment, the control range of the cross angle θ is not 0 to θ _max with respect to the line 17 perpendicular to the rolling pass direction as in the related art, but the inclination of the axis of the reinforcing rolls 3 and 4. The angle θ ₀ is set as a central angle, and control is performed in the range of θ ₀ −Δθ to θ ₀ + Δθ centered on the central angle θ ₀ .

In this way, the crown control range in the conventional method is: C ₁ = (b ² / R) θ _{max In the} ^two methods, C ₂ = (b ² / R) ｛(θ ₀ + Δθ) ² − (Θ ₀ −Δθ) ² ＝= (b ² / R) 4θ ₀ Δθ Assuming that the same effect is obtained, if C ₁ = C ₂ , 4θ ₀ Δθ = θ _max ² Δθ = θ _max ² / 4θ _0, that is, if θ ₀ = θ _max, if _{Δθ = θ max / 4 θ 0} = 1.5θ max, Δθ = θ max / 6 , and the angle between the backup rolls work roll of conventional 1 /
It becomes as small as 4 to 1/6. Therefore, the reinforcing roll 3,
Similarly, the sliding speed in the axial direction between the work rolls 4 and the work rolls 1 and 2 is also reduced, and the change in the roughness of the work roll surface is 1 to 4 to 1
6, and the surface roughness of the work roll is determined by the sliding action with the rolled material. Further, the power loss due to the axial sliding between the rolls can be reduced to 1/4 to 1/6.

FIG. 4 shows a state in which the roll gap, that is, the crown changes according to the cross angle θ. As before,
To obtain the same change amount as change amount [Delta] C _b of the roll gap in the case of controlling up (shown with θ ₁ = ₁ °) θ ₁ from zero for the cross angle theta rolling pass direction perpendicular lines 17, When θ ₀ = 1.2 °, a control amount of ± 0.2 ° is sufficient. That is, the control amount is reduced from 1 ° to 2/5 of 0.4 °, and the deviation amount from the central angle θ ₀ is reduced from 1 ° to 0.2 ° and 1/5. However, this time, when the absolute value of the roll gap C _b is too large, a smaller initial crown C _w of the work rolls, in some cases it is necessary with a concave crown on the work roll. (C _w
<0).

As described above, in this embodiment, the upper work roll 1 is ± 0.2 ° with respect to the center angle line 18, and the lower work roll 2 is the upper work roll with respect to the center angle line 19. By crossing ± 0.2 ° opposite to the cross direction,
Conventionally, the cross angle between the 1 ° work roll and the reinforcing roll is 1/5
To 0.2 °, whereby the relative slip between the rolls can be kept small, and the fluctuations in the surface quality and roughness of the rolled material can be suppressed. In addition, the amount of change in the crown of the plate has been conventionally proportional to the square of the cross angle, but has an effect of being substantially linear and facilitating control.

FIG. 5 is a drawing cited in Japanese Patent Application Laid-Open No. 60-83703. In the hot rolling of iron, the horizontal axis represents the crossing angle of the upper and lower work rolls. This corresponds to twice the angle θ. As can be seen from this figure, under two different types of hot rolling conditions I and II, when the crossing angle 2θ of the upper and lower work rolls is in the range of 0 to 0.5 ° and 1.0 ° or more, the fracture transition temperature is lower. Change. Therefore, if the cross angle θ is controlled in the range of 0 to 1 ° as in the related art,
The intersection angle 2θ is in the range of 0 to 2 °, and the intersection angle 2θ is 0.
Since the fracture surface transition temperature changes when controlled in the range of 5 ° to 1.0 °, the quality of the rolled material on the metallographic structure varies. On the other hand, in the present embodiment, the intersection angle 2
Since θ is always 2 ° or more, the fracture surface transition temperature does not change, and the low-temperature toughness value is improved. Further, the fracture surface transition temperature has a constant value without variation, and uniform quality can be secured.

Further, in this embodiment, the draft screw 10
A straight line connecting the centers 12a and 12b of the center line a with respect to a line 17 perpendicular to the rolling pass direction in the same direction as the upper reinforcing roll 3.
Similarly, the straight line connecting the center 13a of the bearing box receiving surface of the working side and the drive side supporting portion 50a for receiving the bearing boxes 8a and 8b of the lower reinforcing roll 4 is also a line 17 perpendicular to the rolling pass direction. 1.2 ° in the same direction as the lower reinforcing roll 4
The center of the bearing box 7a, 7b, 8a, 8b of the reinforcing roll and the screw 10
a and the deviation from the center of the support portion 50a is reduced,
The rotational moment generated in the bearing housings 7a, 7b, 8a, 8b of the reinforcing rolls is reduced, and the equalizer beam can be omitted.

As described above, according to the present embodiment, the angle between the reinforcing roll and the work roll becomes smaller than before, and the relative slip between the work roll and the reinforcing roll also becomes smaller. By suppressing the change of the ancestry, it is possible to suppress the fluctuation of the surface quality of the rolled material and to prevent the occurrence of the rolling slip. Further, power loss due to axial slippage between the rolls can be reduced.
Further, a large crown control can be performed with a slight change in the cross amount as compared with the related art. In addition, the control amount of the crown is proportional to the square of the cross angle, but becomes substantially linear, thereby facilitating the control. Further, the effect of the cross-rolling of the metal structure in the rolling production can be maintained uniformly. Further, the equalizer beam can be omitted, and the rolling mill can have a small and simple structure.

When the work roll cloth rolling mill according to the present invention is applied by modifying an existing four-high rolling mill,
Although it is easy to incline the axis of the reinforcing roll, it is difficult to incline the center line of the screw-down device unless the mill housing is replaced.

Accordingly, in the modification of the existing four-high rolling mill, the center lines of the rolling device and the reinforcing roll to be diverted are inclined with respect to each other, and a large rigid beam may be required. is there. However, even in this case, in the present invention, since the reinforcing rolls are used in a fixed manner and there is no cross motion, the structure around the large rigid beam is much simpler and more sufficient than the conventional pair cross rolling mill, and the structure according to the present invention is sufficient. It is clear that the rolling mill can be modified to obtain the effect of (1).

An example of the structure of the rolling device and the reinforcing roll bearing box of the present invention will be described with reference to FIGS. 6 and 7. FIG. recently,
For rolling mills for plate rolling mills, a long-stroke hydraulic jack is generally used in a cold rolling mill, while a short-stroke hydraulic jack and a screw-type pass line height adjusting device are generally used in a hot rolling mill. It is.

FIG. 6 shows an embodiment of the present invention in which a long-stroke hydraulic jack is used. A line connecting the centers of the operating hydraulic jack 25a and the driving hydraulic jack 25b is inclined with respect to a line perpendicular to the rolling pass direction. are doing. The bearing box 7a of the operation-side reinforcing roll is pressed to the left side of the drawing by hydraulic cylinders 26 and 27 provided in the operation-side mill housing 9a. To the right side of the, so that there is no play.

FIG. 7 shows an embodiment in which a short-stroke hydraulic jack and a screw down screw are combined. In this embodiment, the screw down screw 10a is arranged on a line perpendicular to the rolling pass direction, while the center of the hydraulic jacks 25a, 25b is arranged. Are inclined with respect to a line perpendicular to the rolling pass direction.

In this embodiment, the center between the hydraulic jack 25a and the screw down 10a is shifted by δ in the drawing.
The rolling force P becomes an unbalanced load, and a rotational moment Pδ generated by the unbalanced load is applied to the unwinding screw as it is. In order to avoid this, in this embodiment, the mill housing 9a is provided with guides 28a and 29a, and
Guide a. At this time, the hydraulic jack 25a can move up and down along the guides 28a and 29a. By doing so, the rotational moment Pδ is adjusted by the hydraulic jack 2
5a and the guide 28a, is received by the reaction force Q by moment Q _L occurring at the contact portion of the 29a, need not applied moment at all to pressure screw 10a. The drive side has the same structure.

In this way, when adjusting the height of the pass line, the hydraulic jack 25a is moved up and down with no rolling load, while the rolling operation is performed by the hydraulic jack 25a during rolling. Both the pressing screws 10a are applied to the respective centers, and a normal pressing operation is performed.

Although FIGS. 6 and 7 show the case where the drafting device is placed on the upper part of the mill, the same effect can be obtained by configuring the lower part of the mill similarly.

Although the guides 28a and 29a in FIG. 7 are of a fixed type, they may be devices which can be moved up and down and horizontally as required.

Further, when the thrust force applied to the work roll crosses in the plus direction with respect to the center angle θ ₀ , the thrust force from the strip and the thrust force from the reinforcing roll cancel each other out, but the thrust force in the minus direction crosses. Then, both the thrust force from the strip and the thrust from the reinforcing roll are applied in the same direction. Therefore, if such thrust force this that applied mutually increases, the present invention may be implemented using only a positive direction with respect to the central angle theta _0.

[0053]

According to the present invention, the following effects can be obtained.

(1) The angle between the reinforcing roll and the work roll becomes smaller than before, the relative slip between the work roll and the reinforcing roll also becomes smaller, and the change in the surface properties and the roughness of the work roll is suppressed. Variations in the surface quality of the rolled material can be suppressed, and the occurrence of rolling slip can be prevented.

(2) Power loss due to axial slippage between rolls can be reduced.

(3) Larger crown control becomes possible with a slight change in the amount of cross as compared with the prior art.

(4) The control amount of the plate crown is proportional to the square of the cross angle, but becomes substantially linear, which facilitates the control.

(5) The effect of the cross-rolling of the metal structure during rolling can be maintained uniformly.

(6) The equalizer beam can be omitted, and the rolling mill can have a small and simple structure.

[Brief description of the drawings]

FIG. 1 is a front view of a four-high rolling mill according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view taken along line II-II of FIG.

FIG. 3 is a diagram illustrating a control range of a center angle and a cross angle of upper and lower work rolls.

FIG. 4 is a cross-angle θ between the upper and lower work rolls and the difference C _b between the upper and lower work roll gaps at a point axially away from the roll center by _b.
FIG.

FIG. 5 is a diagram illustrating a relationship between an intersection angle 2θ and a fracture surface transition temperature.

FIG. 6 is a partial cross-sectional view of a reduction device portion of a four-high rolling mill according to another embodiment of the present invention.

FIG. 7 is a partial cross-sectional view of a reduction device portion of a four-high rolling mill according to still another embodiment of the present invention.

[Explanation of symbols]

1, 2 upper and lower working rolls 3, 4 upper and lower reinforcing rolls 5, 6 working roll bearing box 7, 8 reinforcing roll bearing box 9a operation side mill housing 9b driving side mill housing 10a operation side pressure reduction screw 10b drive side pressure reduction screw 12a, 13a, 12b, 13b Center of rolling-down device and center of bearing box receiving surface 17 Line perpendicular to rolling direction 18 Axis of reinforcing roll 19 Axis of reinforcing roll 20a-21b Hydraulic cylinder (cross device)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B21B 1 / 22,13 / 14 B21B 31 / 24,31 / 32 B21B 37/00-37/78

Claims (9)

(57) [Claims] An upper and lower pair of work rolls and a pair of upper and lower reinforcement rolls respectively supporting the work rolls are fixed, and only the upper and lower pair of work rolls are crossed with each other. In a four-high rolling mill that performs sheet crown control by moving the upper and lower reinforcing rolls, the axes of the upper and lower reinforcing rolls are in the same direction as the upper and lower work rolls with respect to a line perpendicular to the rolling pass direction, and in opposite directions to each other. A four-high rolling mill, wherein the four-high rolling mill is disposed so as to be inclined. 2. The four-high rolling mill according to claim 1, wherein the operation side and the drive side reduction devices for applying the reduction force to the upper and lower reinforcing rolls are formed such that a straight line connecting their centers is a line perpendicular to the rolling pass direction. A four-high rolling mill, which is arranged so as to be inclined in the same direction as the upper and lower reinforcing rolls. 3. A four-high rolling mill according to claim 2, wherein an axis of said upper and lower reinforcing rolls and a straight line connecting the centers of said operation side and drive side rolling down devices are inclined at substantially the same angle with respect to the rolling pass direction. A four-high rolling mill. 4. The four-high rolling mill according to claim 1, further comprising a cross device for tilting the upper and lower work rolls to be cross-moved in opposite directions about the axis of the upper and lower reinforcement rolls. Features a four-high rolling mill. 5. The four-high rolling mill according to claim 2, wherein said operating-side and driving-side pressing-down devices include a hydraulic jack and / or a pressing screw. 6. The four-high rolling mill according to claim 2, wherein the operating-side and drive-side pressing-down devices are configured by combining a hydraulic jack and a pressing-down screw, and a center line of the operating-side and driving-side pressing-down screws is set in a rolling path. A four-high rolling mill characterized in that the center lines of the hydraulic jacks on the operation side and the drive side are inclined with respect to a line perpendicular to the rolling pass direction. 7. The four-high rolling mill according to claim 6, further comprising means for holding a hydraulic jack so as to prevent a moment due to an unbalanced load applied to the hydraulic jack from being transmitted to the screw. Rolling mill. 8. A rolling method for performing sheet crown control by fixing a pair of upper and lower reinforcing rolls of a four-high rolling mill and crossing only a pair of upper and lower working rolls with each other, wherein an axis of the upper and lower reinforcing rolls is provided. Are inclined in the same direction as the upper and lower work rolls and in directions opposite to each other with respect to a line perpendicular to the rolling pass direction, and the cross angle to be controlled is allocated to the plus and minus about the axis of the reinforcing roll. Characteristic rolling method. 9. The rolling method according to claim 8, wherein the cross angle is set to zero with respect to a line perpendicular to the direction of the rolling pass when changing rolls.