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(11) | EP 4 559 593 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
| published in accordance with Art. 153(4) EPC |
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| (54) | 8-STAGE ROLLING MILL, TANDEM ROLLING MILL, AND METHOD FOR MODIFYING ROLLING MILL |
| (57) Provided are one pair of first intermediate rolls 3a and 3b that have tapered roll
shoulders 3c and 3d at point-symmetrical positions in an up-down axis direction and
support one pair of work rolls 2a and 2b that roll a metal strip 1, one pair of second
intermediate rolls 5a and 5b that have tapered roll shoulders 5c and 5d at point-symmetrical
positions in the up-down axis direction opposite to those of the first intermediate
rolls 3a and 3b and support the first intermediate rolls 3a and 3b, one pair of back-up
rolls 7 that support the second intermediate rolls 5a and 5b, support roll groups
12 or support bearings 13 that are provided on an entry side and/or an exit side of
the work rolls 2a and 2b, shift cylinders 50 that shift positions of the roll shoulders
3c and 3d in an axis direction such that the positions align with strip width ends
of the metal strip 1, and shift cylinders 51 that shift positions of the roll shoulders
5c and 5d in an axis direction such that the positions align with strip width ends
of the metal strip 1. As a result, a hard metal strip can more efficiently be rolled
as compared with the prior art, and hence a metal strip small in edge drop and high
in product quality is obtained. |
Technical Field
[0001] The present invention relates to an eight-high rolling mill, a tandem rolling mill, and a modification method for a rolling mill.
Background Art
[0002] In Patent Document 1, there is described such a configuration that at least one rolling mill stand is provided with means for changing a shape of the rolling mill stand, and this convertible rolling mill stand takes at least two shapes each corresponding to one production range while maintaining means for applying a rolling force in the same state.
Prior Art Document
Patent Document
Summary of the Invention
Problems to be Solved by the Invention
[0004] Hitherto, there has been devised the rolling mill described in Patent Document 1 as a rolling mill which uses small-diameter work rolls for rolling a hard metal strip.
[0005] In the eight-high rolling mill described in Patent Document 1, second intermediate rolls can move in an axis direction, but are not provided with tapered shoulders. Thus, as illustrated in regions A of FIG. 1, contact linear pressures, which are called detrimental contact portions, occur from the second intermediate rolls 105a and 105b to the first intermediate rolls 103a and 103b outside a strip width in a strip width direction. Further, as illustrated in regions B of FIG. 1, contact linear pressures, which are called detrimental contact portions, occur from the first intermediate rolls 103a and 103b to the work rolls 102a and 102b also similarly outside the strip width in the strip width direction.
[0006] There has been such a problem that effects of a work roll bender and a first intermediate roll bender decrease due to these detrimental contact portions, and hence a shape control performance decreases. Moreover, there has been such a problem that a shape change amount with respect to a change in rolling load becomes large due to these detrimental contact portions, and hence shape stabilization performance decreases.
[0007] In view of the problems described above, an object of the present invention is to provide an eight-high rolling mill, a tandem rolling mill, and a modification method for modifying a rolling mill, including a work roll support roll group capable of more efficiently rolling a hard metal strip as compared with the prior art and suitable for obtaining a metal strip small in edge drop and high in product quality.
Means for Solving the Problems
[0008] The present application includes a plurality of means which solve the problems described above. An example thereof includes one pair of work rolls that roll a strip, one pair of first intermediate rolls that have first intermediate roll shoulders at point-symmetrical positions in an up-down axis direction and that support the one pair of work rolls, one pair of second intermediate rolls that have tapered second intermediate roll shoulders at point-symmetrical positions in the up-down axis direction opposite to those of the first intermediate rolls and support the first intermediate rolls, one pair of back-up rolls that support the second intermediate rolls, support roll groups or support bearings that are provided on an entry side and/or an exit side in the work rolls, first intermediate roll shift devices that shift the positions of the first intermediate roll shoulders in an axis direction such as to align with strip width ends of the strip, and second intermediate roll shift devices that shift the positions of the second intermediate roll shoulders in an axis direction such as to align with the strip width ends of the strip.
Advantages of the Invention
[0009] According to the present invention, a hard metal strip can more efficiently be rolled as compared with the prior art, and moreover, a metal strip small in edge drop, and hence high in product quality can be obtained. Purposes, configurations, and effects other than the description given above become apparent from the following description of embodiments.
Brief Description of the Drawings
[0010]
FIG. 1 is an explanatory view of a linear pressure distribution of a conventional eight-high rolling mill.
FIG. 2 is a front view of an eight-high rolling mill according to a first embodiment.
FIG. 3 is a cross-sectional view made in a direction indicated by arrows A-A of FIG. 2.
FIG. 4 is a cross-sectional view made in a direction indicated by arrows B-B of FIG. 2.
FIG. 5 is an explanatory view of a linear pressure distribution of the eight-high rolling mill according to the first embodiment.
FIG. 6 is a front view of a six-high rolling mill according to a second embodiment after switching.
FIG. 7 is a cross-sectional view made in a direction indicated by arrows C-C of FIG. 6.
FIG. 8 is a front view of an eight-high rolling mill according to a third embodiment.
FIG. 9 is a cross-sectional view made in a direction indicated by arrows D-D of FIG. 8.
FIG. 10 is a diagram for describing work roll offset adjustment of the eight-high rolling mill according to the third embodiment.
FIG. 11 is a diagram for describing a load applied to a work roll at the time of the work roll offset of the eight-high rolling mill according to the third embodiment.
FIG. 12 is a front view of an eight-high rolling mill according to a fourth embodiment.
FIG. 13 is a diagram for describing intermediate roll offset adjustment of the eight-high rolling mill according to the fourth embodiment.
FIG. 14 is a diagram for describing a load applied to the work roll at the time of the intermediate roll offset of the eight-high rolling mill according to the fourth embodiment.
FIG. 15 is an explanatory diagram of deflection of the work roll of the eight-high rolling mill according to the fourth embodiment.
FIG. 16 is a front view of an eight-high rolling mill according to a sixth embodiment.
FIG. 17 is a cross-sectional view made in a direction indicated by arrows E-E of FIG. 16.
FIG. 18 is a side view of an eight-high rolling mill according to a seventh embodiment.
FIG. 19 is a cross-sectional view made in a direction indicated by arrows F-F of FIG. 18.
FIG. 20 is a detailed explanatory view of another eight-high rolling mill according to the seventh embodiment.
FIG. 21 is a detailed explanatory view of an eight-high rolling mill according to an eighth embodiment.
FIG. 22 is a plan view of the eight-high rolling mill according to the eighth embodiment.
FIG. 23 is an explanatory view of a tandem rolling mill according to a ninth embodiment.
Modes for Carrying Out the Invention
[0011] A description is now given of an eight-high rolling mill, a tandem rolling mill, and a modification method for a rolling mill according to the present invention with reference to the drawings. Note that, in the drawings used in the present specification, there is such a case in which the same or corresponding component is assigned with the same or a similar reference character and a redundant description of this component is omitted.
<First Embodiment>
[0012] A description is now given of a first embodiment of a rolling mill according to the present invention with reference to FIG. 2 to FIG. 5.
[0013] First, a description is given of an overall configuration of an eight-high rolling mill with reference to FIG. 2 to FIG. 4. FIG. 2 is a front view of the eight-high rolling mill according to the first embodiment, FIG. 3 is a cross-sectional view made in a direction indicated by arrows A-A of FIG. 2, and FIG. 4 is a cross-sectional view made in a direction indicated by arrows B-B of FIG. 2.
[0014] The rolling mill illustrated in FIG. 2 to FIG. 4 is the eight-high rolling mill which rolls a metal strip 1 and includes work rolls 2a and 2b, first intermediate rolls 3a and 3b, second intermediate rolls 5a and 5b, back-up rolls 7a and 7b, housings 11a and 11b, thrust bearings 21a and 21b, shafts 22a and 22b, first intermediate roll bearings 4a, 4b, 4c, and 4d, first intermediate roll chocks 4e and 4f, bending cylinders 23a, 23b, 23c, and 23d, shift cylinders 50a and 50b, second intermediate roll bearings 6a, 6b, 6c, and 6d, second intermediate roll chocks 6e and 6f, bending cylinders 24a, 24b, 24c, and 24d, shift cylinders 51a and 51b, back-up roll chock 8a, 8b, 8c, and 8d, pass line adjusting devices 9a and 9b, screw-down hydraulic cylinders 10a and 10b, support rolls 12a, 12b, 12c, and 12d, support bearings 13a, 13b, 13c, 13d, 13e, 13f, 13g, and 13h, arms 15a, 15b, 15c, and 15d, shafts 16a, 16b, 16c, and 16d, side blocks 17a, 17b, 17c, and 17d, tapered wedges 18a, 18b, 18c, 18d, 18e, 18f, 18g, and 18h, tapered wedges 19a, 19b, 19c, 19d, 19e, 19f, 19g, and 19h, hydraulic cylinders 20a, 20b, 20c, 20d, 20e, 20f, 20g, and 20h, a control device 60, and the like.
[0015] Note that, in FIG. 2 and the like, when components have reference characters suffixed by "a, b, c, d, e, f, g, and h," basically, a top exit side and a work side of the metal strip 1 is denoted by "a," the top exit side and a drive side of the metal strip 1 is denoted by "b," a bottom exit side and the work side of the metal strip 1 is denoted by "c," the bottom exit side and the drive side of the metal strip 1 is denoted by "d," a top entry side and the work side of the metal strip 1 is denoted by "e," the top entry side and the drive side of the metal strip 1 is denoted by "f," a bottom entry side and the work side of the metal strip 1 is denoted by "g," and the bottom entry side and the drive side of the metal strip 1 is denoted by "h."
[0016] Moreover, in FIG. 2 and the like, when components have reference characters suffixed by "a, b, c, and d," basically, the top exit side of the metal strip 1 is denoted by "a," the bottom exit side of the metal strip 1 is denoted by "b," the top entry side of the metal strip 1 is denoted by "c," and the bottom entry side of the metal strip 1 is denoted by "d."
[0017] The one pair of top and bottom work rolls 2a and 2b are rolls which roll the metal strip 1 being a metal strip to be rolled. The one pair of top and bottom work rolls 2a and 2b are in contact with and are supported by the one pair of top and bottom first intermediate rolls 3a and 3b, respectively. Further, the one pair of top and bottom first intermediate rolls 3a and 3b are in contact with and are supported by the one pair of top and bottom second intermediate rolls 5a and 5b, respectively. Moreover, the one pair of top and bottom second intermediate rolls 5a and 5b are in contact with and are supported by the one pair of top and bottom back-up rolls 7a and 7b, respectively.
[0018] The back-up roll 7a on the top side is supported by bearings (omitted for the convenience of illustration) and the back-up roll chocks 8a and 8b. The back-up roll chocks 8a and 8b are supported by the housings 11a and 11b via the pass line adjusting devices 9a and 9b.
[0019] Each of the pass line adjusting devices 9a and 9b is formed of a worm jack or a tapered wedge and a stepped rocker strip, and the like. A loadcell (not illustrated) may be incorporated into each of the pass line adjusting devices 9a and 9b, thereby measuring a rolling load.
[0020] Moreover, the back-up roll 7b on the bottom side is supported by bearings (not illustrated) and the back-up roll chocks 8c and 8d, and the back-up roll chocks 8c and 8d are supported by the housing 11a and 11b via the screw-down hydraulic cylinders 10a and 10b.
[0021] The top first intermediate roll 3a has a roll shoulder 3c in a tapered shape at a roll body end position that is point-symmetrical in the up-down axis direction to the bottom first intermediate roll 3b relative to a strip width center of the metal strip 1. The bottom first intermediate roll 3b has a roll shoulder 3d in a tapered shape at a roll body end position that is point-symmetrical in the up-down axis direction to the top first intermediate roll 3a relative to the strip width center of the metal strip 1.
[0022] Moreover, the top first intermediate roll 3a has roll neck portions to which first intermediate roll bearings 4a and 4c and a first intermediate roll chock 4e are attached via bearings (not illustrated). The bottom first intermediate roll 3b has roll neck portions to which first intermediate roll bearings 4b and 4d and a first intermediate roll chock 4f are attached via bearings (not illustrated).
[0023] The top first intermediate roll 3a is movable in an axis direction by the shift cylinder 50a via the first intermediate roll chock 4e on the drive side. Moreover, the bearings 4a and 4c are provided with the bending cylinders 23a and 23c which apply roll bending. The roll bending is thereby applied to the first intermediate roll 3a.
[0024] The bottom first intermediate roll 3b is movable in an axis direction by the shift cylinder 50b via the first intermediate roll chock 4f on the drive side. Moreover, bearings 4b and 4d are provided with the bending cylinders 23b and 23d which apply roll bending. The roll bending is thereby applied to the first intermediate roll 3b.
[0025] The shift cylinders 50a and 50b shift the positions of the roll shoulders 3c and 3d of the first intermediate rolls 3a and 3b in the axis directions such that the positions align with the ends of strip width ends of the metal strip 1 on sides closer to the roll shoulders 3c and 3d, respectively. Note that, in the present invention, "align the positions of the roll shoulders 3c and 3d of the first intermediate rolls 3a and 3b with the strip width ends of the metal strip 1, respectively" is not required to mean, in a strict sense, that the positions of the roll shoulders 3c and 3d of the first intermediate rolls 3a and 3b align with the strip width ends of the metal strip 1 and it is assumed that the positions of the roll shoulders 3c and 3d of the first intermediate rolls 3a and 3b are shifted so as to align with the strip width ends of the metal strip 1 and vicinities thereof in a range of regions called detrimental contact portions being enabled to be removed.
[0026] The top second intermediate roll 5a has a roll shoulder 5c in a tapered shape at a position that is point-symmetrical to the top first intermediate roll 3a on an opposite side in the strip width direction and at a roll body end position that is point-symmetrical in the up-down axis direction relative to the strip width center of the metal strip 1. The bottom second intermediate roll 5b has a roll shoulder 5d in a tapered shape at a position that is point-symmetrical to the bottom first intermediate roll 3b on an opposite side in the strip width direction and at a roll body end position that is point-symmetrical in the up-down axis direction relative to the strip width center of the metal strip 1.
[0027] Moreover, the top second intermediate roll 5a has roll neck portions to which second intermediate roll bearings 6a and 6c are attached via bearings (not illustrated). The bottom second intermediate roll 5b has roll neck portions to which second intermediate roll bearings 6b and 6d are attached via bearings (not illustrated).
[0028] The top second intermediate roll 5a is movable in an axis direction by the shift cylinder 51a via the second intermediate roll chock 6e on the drive side. The bearings 5a and 5c of the second intermediate roll 5a are provided with the bending cylinders 24a and 24c for applying roll bending. The roll bending is thereby applied to the second intermediate roll 5a.
[0029] The bottom second intermediate roll 5b is movable in an axis direction by the shift cylinder 51b via the second intermediate roll chock 6f on the drive side. The bearings 5b and 5d of the second intermediate roll 5b are provided with the bending cylinders 24b and 24d for applying roll bending. The roll bending is thereby applied to the second intermediate roll 5b.
[0030] The shift cylinders 51a and 51b shift the positions of the roll shoulders 5c and 5d of the second intermediate rolls 5a and 5b in an axis direction such that the positions align with the ends of the strip width ends of the metal strip 1 on sides closer to the roll shoulders 5c and 5d, respectively. Note that, in the present invention, "the positions of the roll shoulders 5c and 5d of the second intermediate rolls 5a and 5b align with the strip width ends of the metal strip 2, respectively" is not required to mean, in a strict sense, that the positions of the roll shoulders 5c and 5d of the second intermediate rolls 5a and 5b align with the strip width ends of the metal strip 1 and it is assumed that the positions of the roll shoulders 5c and 5d of the second intermediate rolls 5a and 5b are shifted so as to align with the strip width ends of the metal strip 1 and vicinities thereof in a range of regions called detrimental contact portions being enabled to be removed.
[0031] The one pair of top and bottom work rolls 2a and 2b are supported at a work side shaft end by the thrust bearing 21a and at a drive side shaft end by the thrust bearing 21b. The thrust bearing 21a and 21b are rotatably attached to brackets (not illustrated) via the shafts 22a and 22b.
[0032] The top work roll 2a is rotatably supported by the support roll 12a on its entry side of the metal strip 1 over a full length in the strip width direction and is rotatably supported by the support roll 12c on its exit side of the metal strip 1 over a full length in the strip width direction. The support roll 12a is rotatably supported by the support bearings 13a and 13b, and the support roll 12c is rotatably supported by the support bearings 13e and 13f.
[0033] The bottom work roll 2b is rotatably supported by the support roll 12b on its entry side of the metal strip 1 over a full length in the strip width direction and is rotatably supported by the support roll 12d on its exit side of the metal strip 1 over an entire length in the strip width direction. The support roll 12b is rotatably supported by the support bearings 13c and 13d, and the support roll 12d is rotatably supported by the support bearings 13g and 13h.
[0034] The support bearings 13a and 13b are rotatably supported by the arm 15a via the shafts 14a and 14b. The support bearings 13c and 13d are rotatably supported by the arm 15b via the shafts 14c and 14d. The support bearing 13e and 13f are rotatably supported by the arm 15c via the shafts 14e and 14f. The support bearing 13g and 13h are rotatably supported by the arm 15d via the shafts 14g and 14h.
[0035] The arm 15a is swingably attached to the first intermediate roll bearing 4a via the shaft 16a and is supported by the side block 17a in the pass direction. The arm 15b is swingably attached to the first intermediate roll bearing 4b via the shaft 16b and is supported by the side block 17b in the pass direction. The arm 15c is swingably attached to the first intermediate roll bearing 4c via the shaft 16c and is supported by the side block 17c in the pass direction. The arm 15d is swingably attached to the first intermediate roll bearing 4d via the shaft 16d and is supported by the side block 17d in the pass direction.
[0036] As a result, pass direction positions of the arms 15a, 15b, 15c, and 15d are adjusted through use of the side blocks 17a, 17b, 17c, and 17d capable of adjusting the pass direction positions, thereby being able to change offset amounts of the work rolls 2a and 2b in the pass direction.
[0037] Further, the side block 17a is supported by the housings 11a and 11b via the tapered wedges 18a, 18b, 19a, and 19b. The side block 17b is supported by the housings 11a and 11b via the tapered wedges 18c, 18d, 19c, and 19d. The side block 17c is supported by the housings 11a and 11b via the tapered wedges 18e, 18f, 19e, and 19f. The side block 17d is supported by the housings 11a and 11b via the tapered wedges 18g, 18h, 19g, and 19h.
[0038] The tapered wedges 18a and 18b are pulled and inserted by the hydraulic cylinders 20a and 20b, thereby being able to change thicknesses thereof. The tapered wedges 18c and 18d are pulled and inserted by the hydraulic cylinders 20c and 20d, thereby being able to change thicknesses thereof. The tapered wedges 18e and 18f are pulled and inserted by the hydraulic cylinders 20e and 20f, thereby being able to change thicknesses thereof. The tapered wedges 18g and 18h are pulled and inserted by the hydraulic cylinders 20g and 20h, thereby being able to change thicknesses thereof.
[0039] For example, in a case in which work rolls having large diameters are replaced by work rolls having small diameters, when the tapered wedges 18a, 18b, 18c, 18d, 18e, 18f, 18g, and 18h are pushed in, the thicknesses thereof increase, and the side blocks 17a, 17b, 17c, and 17d move toward a mill inside by a corresponding amount. Thus, the support rolls 12a, 12b, 12c, and 12d are also closed toward the mill inside via the arms 15a, 15b, 15c, and 15d, the shafts 16a, 16b, 16c, and 16d, and the support bearings 13a, 13b, 13c, 13d, 13e, 13f, 13g, and 13h and hence can be brought into a state in which the support rolls 12a, 12b, 12c, and 12d are in contact with and support the work rolls having the small diameter.
[0040] Conversely, in a case in which work rolls having a small diameter is replaced by work rolls having a large diameter, when the tapered wedges 18a, 18b, 18c, and 18d are pulled out, the thicknesses thereof decrease, and the side blocks 17a, 17b, 17c, and 17d move toward a mill outside by a corresponding amount. Thus, the support rolls 12a, 12b, 12c, and 12d are also opened toward the mill outside via the arms 15a, 15b, 15c, and 15d, the shafts 16a, 16b, 16c, and 16d, and the support bearings 13a, 13b, 13c, 13d, 13e, 13f, 13g, and 13h and hence can be brought into a state in which the support rolls 12a, 12b, 12c, and 12d are in contact with and support the work rolls having the large diameter.
[0041] In the embodiment, the moving-in/moving-out method for the tapered wedges 18a, 18b, 18c, 18d, 18e, 18e, 18g, and 18h are described, but a motor-driven worm jack method may be employed.
[0042] The control device 60 is a device which controls an operation of each device in the rolling mill described above such as the shift cylinders 50a, 50b, 51a, and 51b. The control device 60 can be formed of a computer including a monitor such as a liquid crystal display, an input device, a storage device, a CPU, and a memory described later, may be formed of one computer or may be formed of another computer, and the configuration is not particularly limited.
[0043] The control of the operation of each device by the control device 60 is executed on the basis of various programs recorded in the storage device. Note that the control processing for the operations executed by the control device 60 may be unified into one program or may be divided into a plurality of programs and may be a combination thereof. Moreover, a part of or the whole of the program may be implemented by dedicated hardware or may be modularized.
[0044] Moreover, there is described the example in which the support rolls 12a, 12b, 12c, and 12d, the support bearings 13a, 13b, 13c, 13d, 13e, 13f, 13g, and 13h, the shafts 14a, 14b, 14c, 14d, 14e, 14f, 14g, and 14h, and the arms 15a, 15b, 15c, and 15d are swingably attached to the first intermediate roll bearings 4a, 4b, 4c, and 4d, via the shafts 16a, 16b, 16c, and 16d, but the support rolls 12a, 12b, 12c, and 12d, the support bearings 13a, 13b, 13c, 13d, 13e, 13f, 13g, and 13h, the shafts 14a, 14b, 14c, 14d, 14e, 14f, 14g, and 14h, and the arms 15a, 15b, 15c, and 15d may swingably be attached to the side blocks 17a, 17b, 17c, and 17d, via the shafts 16a, 16b, 16c, and 16d. Moreover, there may be provided such a structure that the support rolls 12a, 12b, 12c, and 12d and the support bearings 13a, 13b, 13c, 13d, 13e, 13f, 13g, and 13h are directly supported by hydraulic cylinders or worm jacks.
[0046] The rolling mill according to the first embodiment of the present invention described above includes the one pair of work rolls 2a and 2b that roll the metal strip 1, the one pair of first intermediate rolls 3a and 3b that have the tapered roll shoulders 3c and 3d at the point-symmetrical positions in the up-down axis direction and support the one pair of work rolls 2a and 2b, the one pair of second intermediate rolls 5a and 5b that have the tapered shoulders 5c and 5d at the point-symmetrical positions in the up-down axis direction opposite to those of the first intermediate rolls 3a and 3b and support the first intermediate rolls 3a and 3b, the one pair of back-up rolls 7a and 7b that support the second intermediate rolls 5a and 5b, the group of support rolls 12a, 12b, 12c, and 12d or the support bearings 13a, 13b, 13c, 13d, 13e, 13f, 13g, and 13h that are provided on the entry side and/or the exit side of the work rolls 2a and 2b, the shift cylinders 50a and 50b that shift the positions of the roll shoulders 3c and 3d in an axis direction so as to align with the strip width ends of the metal strip 1, and the shift cylinders 51a and 51b that shift the positions of the roll shoulders 5c and 5d in an axis direction so as to align with the strip width ends of the metal strip 1.
[0047] With this configuration, as illustrated in regions C of FIG. 5, by shifting the tapered shoulder positions of the first intermediate rolls 3a and 3b so as to align with the vicinities of the strip width ends at the up and down point-symmetrical positions, it is possible to remove the contact linear pressures called detrimental contact portions which exist on the sides on which the tapered shoulder positions of the first intermediate rolls 3a and 3b exist, the contact linear pressures being applied from the first intermediate rolls 3a and 3b to the work rolls 2a and 2b outside the strip width in the strip width direction.
[0048] Further, as illustrated in regions D of FIG. 5, by shifting, at the positions point-symmetrical to the first intermediate rolls 3a and 3b on the opposite sides in the strip width direction, the tapered shoulder positions of the second intermediate rolls 5a and 5b so as to align with the vicinities of the strip width ends at the up and down point-symmetrical positions, it is possible to remove the contact linear pressures called detrimental contact portions, the contact linear pressures being applied from the second intermediate rolls 5a and 5b to the first intermediate rolls 3a and 3b outside the strip width. With these configurations, on the work side and the drive side of the strip width, the detrimental contact portions can be removed on the top and bottom sides of the roll dispositions.
[0049] As a result, effects of a work roll bender and a first intermediate roll bender increases, resulting in an increase in shape control performance. Moreover, a shape change amount with respect to a change in a rolling load decreases, resulting in an increase in shape stabilization performance. The rolling mill becomes appropriate, for example, for obtaining a metal strip small in sharp decrease in strip thickness at the strip ends, which is called edge drop, and high in product quality can be obtained. The rolling mill according to the present invention as described above is suitable for obtaining a metal strip high in productivity and high in product quality when the metal strip 1 is a hard metal strip.
<Second Embodiment>
[0050] A description is now given of a rolling mill and a method of modifying a rolling mill according to a second embodiment of the present invention with reference to FIG. 6 and FIG. 7. FIG. 6 is a front view of a six-high rolling mill according to a second embodiment after switching, and FIG. 7 is a cross-sectional view made in a direction indicated by arrows C-C of FIG. 6.
[0051] In the six-high rolling mill illustrated in FIG. 6, the metal strip 1 being the metal strip to be rolled is rolled by one pair of top and bottom work rolls 25a and 25b. The one pair of top and bottom work rolls 25a and 25b are in contact with and are supported by one pair of top and bottom intermediate rolls 27a and 27b, respectively. The pair of top and bottom intermediate rolls 27a and 27b are in contact with and are supported by the one pair of top and bottom back-up rolls 7a and 7b, respectively.
[0052] The top work roll 25a is rotatably attached to work roll bearings 26a and 26c via bearings (not illustrated) on its work side and drive side. The bottom work roll 25b is rotatably attached to work roll bearings 26b and 26d via bearings (not illustrated) on its work side and drive side.
[0053] The work roll bearings 26a and 26c are provided with bending cylinders 29a and 29c which apply the roll bending, respectively, thereby applying the roll bending to the work roll 25a. Moreover, the work roll bearings 26b and 26d are provided with bending cylinders 29b and 29d which apply the roll bending, respectively, thereby applying the roll bending to the work roll 25b.
[0054] Moreover, the top intermediate roll 27a has a roll shoulder 27c in a tapered shape at a roll body end position that is point-symmetrical in the up-down direction to the bottom intermediate roll 27b relative to the strip width center of the metal strip 1. The top intermediate roll 27a is movable in an axis direction by a shift cylinder 52a via an intermediate roll chock 28e on the drive side.
[0055] The bottom intermediate roll 27b has a roll shoulder 27d in a tapered shape at a roll body end position that is point-symmetrical in the up-down direction to the top intermediate roll 27a relative to the strip width center of the metal strip 1. The bottom intermediate roll 27b is movable in an axis direction by a shift cylinder 52b via an intermediate roll chock 28f on the drive side.
[0056] The roll bearings 28a and 28c are provided with bending cylinders 24a and 24c which apply the roll bending, respectively, thereby applying the roll bending to the intermediate roll 27a. Moreover, the roll bearings 28b and 28d are provided with bending cylinders 24b and 24d which apply the roll bending, respectively, thereby applying the roll bending to the intermediate roll 27b.
[0057] In the embodiment, by pulling out the one pair of top and bottom work rolls 25a and 25b provided with the work roll bearings 26a, 26b, 26c, and 26d and the one pair of top and bottom intermediate rolls 27a and 27b provided with the intermediate roll bearings 28a, 28b, 29c, and 29d to the work side of the housing 11a and 11b, respectively, and inserting, in place thereof, the work rolls 2a and 2b, the one pair of top and bottom first intermediate rolls 3a and 3b provided with the first intermediate roll bearings 4a, 4b, 4c, and 4d, and the one pair of top and bottom second intermediate roll 5a and 5b provided with the second intermediate roll bearings 6a, 6b, 6c, and 6d of the eight-high rolling mill described in the first embodiment into the housing 11a and 11b, switching between the six-high rolling mill and the eight-high rolling mill is enabled.
[0058] For example, in the rolling of a hard metal strip, the work rolls 2a and 2b having a smaller diameter of the eight-high rolling mill suitable for the rolling of the hard metal strip can be used, and in the rolling of a soft metal strip, the eight-high rolling mill is switched to the six-high rolling mill and the work rolls 25a and 25b having a medium diameter suitable for the rolling of the soft metal strip can be used.
[0059] Here, in Patent Document 1, there is described that in the switching between the six-high rolling mill and the eight-high rolling mill, a sum of the work roll diameter and the first intermediate roll diameter of the eight-high rolling mill are substantially the same as the work roll diameter of the six-high rolling mill. However, with this configuration, the work roll diameter of the six-high rolling mill is large, and hence there poses such a problem that an effect of the small diameter of the work rolls as the six-high rolling mill decreases.
[0060] Thus, it is preferred that a sum of the maximum diameter of the work rolls 2a and 2b, the maximum diameter of the first intermediate rolls 3a and 3b, and the maximum diameter of the second intermediate rolls 5a and 5b of the eight-high rolling mill be the same or within a range of an error of ±10% of a sum of the maximum diameter of the work rolls 25a and 25b and the maximum diameter of the intermediate rolls 27a and 27b of the six-high rolling mill. It is more preferred that the sum be within a range of the error of ±5% and it is still more preferred that the sum be within a range of the error of ±2%.
[0061] Moreover, in addition to or in place of this configuration, it is preferred that a sum of the minimum diameter of the work rolls 2a and 2b, the minimum diameter of the first intermediate rolls 3a and 3b, and the minimum diameter of the second intermediate rolls 5a and 5b of the eight-high rolling mill be the same or within a range of an error of ±10% of a sum of the minimum diameter of the work rolls 25a and 25b and the minimum diameter of the intermediate rolls 27a and 27b of the six-high rolling mill. It is more preferred that the sum be within a range of the error of ±5% and it is still more preferred that the sum be within a range of the error of ±2%.
[0062] Other configurations and operations of the rolling mill are substantially the same configurations and operations of the rolling mill according to the first embodiment, and hence details thereof are omitted.
[0063] Also in the rolling mill according to the second embodiment of the present invention, there are provided effects substantially similar to those of the rolling mill according to the first embodiment described before.
[0064] Moreover, with the modification method for the rolling mill according to the second embodiment of the present invention, a combination of the work rolls 2a and 2b, the first intermediate rolls 3a and 3b, and the second intermediate rolls 5a and 5b of the eight-high rolling mill can easily be replaced by a combination of the work rolls 25a and 25b and the intermediate rolls 27a and 27b of the six-high rolling mill without a great adjustment. As a result, there is obtained such an effect that inner surface heights of the housing both thereof are substantially the same, which is particularly advantageous at the time of the modification. Moreover, the diameter of the work rolls 25a and 25b of the six-high rolling mill can be small, and hence the effect of the small diameter of the work rolls 25a and 25b as the six-high rolling mill can be utilized.
[0065] Moreover, by setting the sum of the maximum diameters or the minimum diameters of the work rolls 2a and 2b, the first intermediate rolls 3a and 3b, and the second intermediate rolls 5a and 5b of the eight-high rolling mill to be the same as or to have an error of ±10% of the sum of the maximum diameters or the minimum diameters of the work rolls 25a and 25b and the intermediate rolls 27a and 27b, the inner surface heights of the housings both thereof can be the same, which is more advantageous particularly in a case in which the six-high rolling mill is modified to a switching mill between eight highs and six highs.
<Third Embodiment>
[0066] A description is now given of a rolling mill according to a third embodiment of the present invention with reference to FIG. 8 to FIG. 11. FIG. 8 is a front view of an eight-high rolling mill according to a third embodiment, and FIG. 9 is a cross-sectional view made in a direction indicated by arrows D-D of FIG. 8.
[0067] As illustrated in FIG. 8 and FIG. 9, the rolling mill according to the third embodiment is the eight-high rolling mill, and the metal strip 1 being the metal strip to be rolled is rolled by the one pair of the top and bottom work rolls 2a and 2b.
[0068] The work roll 2a is rotatably supported by support bearings 30e and 30f installed on the work side and the drive side on the entry side in the horizontal direction and is rotatably supported by support bearings 30a and 30b installed on the work side and the drive side on the exit side in the horizontal direction. The work roll 2b is rotatably supported by support bearings 30g and 30h installed on the work side and the drive side on the entry side in the horizontal direction and is rotatably supported by support bearings 30c and 30d installed on the work side and the drive side on the exit side in the horizontal direction.
[0069] The support bearings 30a and 30b are rotatably supported by arms 32a and 32b via shafts 31a and 31b. The arms 32a and 32b are swingably attached to the first intermediate roll bearing 4a via the shaft 16a. The support bearings 30c and 30d are rotatably supported by arms 32c and 32d via shafts 31c and 31d. The arms 32c and 32d are swingably attached to the first intermediate roll bearing 4b via the shaft 16b. The support bearings 30e and 30f are rotatably supported by arms 32e and 32f via shafts 31e and 31f. The arms 32e and 32f are swingably attached to the first intermediate roll bearing 4c via the shaft 16c. The support bearing 30g and 30h are rotatably supported by arms 32g and 32h via shafts 31g and 31h. The arms 32g and 32h are swingably attached to the first intermediate roll bearing 4d via the shaft 16d.
[0070] The arms 32a and 32b are supported in the pass direction by the side block 17a. The arms 32c and 32d are supported in the pass direction by the side block 17b. The arms 32e and 32f are supported in the pass direction by the side block 17c. The arms 32g and 32h are supported in the pass direction by the side block 17d.
[0071] As a result, the pass direction positions of the arms 15a, 15b, 15c, and 15d are adjusted through use of the side blocks 17a, 17b, 17c, and 17d capable of adjusting the pass direction positions, thereby being able to change the offset amounts in the pass direction of the work rolls 2a and 2b.
[0072] Further, the side block 17a is supported by the housings 11a and 11b via the tapered wedges 18a, 18b, 19a, and 19b. The side block 17b is supported by the housings 11a and 11b via the tapered wedges 18c, 18d, 19c, and 19d. The side block 17c is supported by the housings 11a and 11b via the tapered wedges 18e, 18f, 19e, and 19f. The side block 17d is supported by the housings 11a and 11b via the tapered wedges 18g, 18h, 19h, and 19h.
[0073] The tapered wedges 18a and 18b are pulled and inserted by the hydraulic cylinders 20a and 20b, thereby being able to change thicknesses thereof. The tapered wedges 18c and 18d are pulled and inserted by the hydraulic cylinders 20c and 20d, thereby being able to change thicknesses thereof. The tapered wedges 18e and 18f are pulled and inserted by the hydraulic cylinders 20e and 20f, thereby being able to change thicknesses thereof. The tapered wedges 18g and 18h are pulled and inserted by the hydraulic cylinders 20g and 20h, thereby being able to change thicknesses thereof.
[0074] For example, when the tapered wedges 18e, 18f, 18g, and 18h on the entry side are pushed in, the thicknesses thereof increase, the side blocks 17b and 17d move toward the exit side by a corresponding amount, and the work rolls 2a and 2b move toward the exit side by an offset δ via the arms 32e, 32f, 32g, and 32h, the shafts 31e, 31f, 31g, and 31h, and the support bearings 30e, 30f, 30g, and 30h.
[0075] When the tapered wedges 18a, 18b, 18c, and 18d on the exit side are simultaneously pulled out, the thicknesses thereof decrease, the side blocks 17a and 17c move toward the exit side by a corresponding amount, and the support bearings 30a, 30b, 30c, and 30d also move toward the exit side by δ via the arms 32a, 32b, 32c, and 32d, and the shafts 31a, 31b, 31c, and 31d, thereby supporting the work rolls 2a and 2b.
[0076] In this example, the moving-in/moving-out method for the tapered wedges 18a, 18b, 18c, 18d, 18e, 18e, 18g, and 18h are described, but a motor-driven worm jack method may be employed.
[0077] The work roll 2a is provided with a cobble guard 33c on the entry side of a center portion thereof and a coolant spray header 35a is provided to the cobble guard 33c. The coolant spray header 35a cools and lubricates the work roll 2a. The work roll 2b is provided with a cobble guard 33d on the entry side of a center portion thereof, and a coolant spray header 35b is provided to the cobble guard 33d. The coolant spray header 35b cools and lubricates the work roll 2b.
[0078] Further, a plurality of zones in the strip width direction may be provided to each of the coolant spray headers 35a and 35b, and a flow rate of the coolant may be variable or may be set to on or off for each of the zones. The strip shape control is thereby enabled.
[0079] For example, when the strip is locally tight (not stretched) in the strip width direction, by reducing or setting to off the flow rate of the coolant of each of the coolant spray headers 35a and 35b in the zone at the same position in the strip width direction, the cooling of the work rolls 2a and 2b is suppressed by a corresponding amount, thermal expansion of this portion increases by a corresponding amount, the diameter increases, and the state in which the strip shape is tight only in this portion transitions to a state in which the strip shape is stretched, resulting in a flat shape.
[0080] The cobble guards 33c and 33d are retractable through hydraulic cylinders 34c and 34d fixed to the housing 11a and 11b at the time of roll replacement of the first intermediate rolls 3a and 3b.
[0081] The present embodiment describes the example in which the coolant spray headers 35a and 35b are installed on the entry side, but may be installed on the exit side or may be installed on the entry side and the exit side.
[0082] Moreover, the application of the coolant spray header 35a to the plurality of zones in the strip width direction in order for the strip shape control is effective only on the top side. When the coolant spray header is provided also on the bottom side, the effect thereof increases.
[0083] Moreover, it is possible to provide cobble guards 33a and 33b to exit sides of center portions of the work rolls 2a and 2b, thereby preventing broken pieces of the strip from being caught in the rolls at a time of a strip breakage on the exit side of the mill and preventing the coolant from falling onto the strip for a purpose of removing water.
[0084] In this example, there is described the example in which the support bearings 30a, 30b, 30c, 30d, 30e, 30f, 30g, and 30h, the shafts 31a, 31b, 31c, 31d, 31e, 31f, 31g, and 31h, and the arms 32a, 32b, 32c, 32d, 32e, 32f, 32g, and 32h are swingably attached to the first intermediate roll bearings 4a, 4b, 4c, and 4d, via the shafts 16a, 16b, 16c, and 16d, but the support bearings 30a, 30b, 30c, 30d, 30e, 30f, 30g, and 30h, the shafts 31a, 31b, 31c, 31d, 31e, 31f, 31g, and 31h, and the arms 32a, 32b, 32c, 32d, 32e, 32f, 32g, and 32h may swingably be attached to the side blocks 17a, 17b, 17c, and 17d, via the shafts 16a, 16b, 16c, and 16d. Moreover, there may be provided such a structure that the support bearings 30a, 30b, 30c, 30d, 30e, 30f, 30g, and 30h are directly supported by hydraulic cylinders or worm jacks.
[0085] Moreover, in the present embodiment, the cobble guards 33c and 33d to which the coolant spray headers 35a and 35b are attached and the cobble guards 33a and 33b are retractable by the hydraulic cylinders 34a, 34b, 34c, and 34d fixed to the housing 11a and 11b, but the cobble guards 33c and 33d to which the coolant spray headers 35a and 35b are attached and the cobble guards 33a and 33b may be mounted to the first intermediate roll bearings 4a, 4b, 4c, and 4d.
[0086] A description is now given of a setting method for the offset positions of the work rolls with reference to FIG. 10 and FIG. 11. FIG. 10 is a diagram for describing the work roll offset adjustment, and FIG. 11 is a diagram for describing a load applied to the work roll at the time of the work roll offset.
[0087] First, in a case in which the first intermediate rolls 3a and 3b are driven, a work roll horizontal force Fwh applied to the work rolls 2a and 2b is obtained by Equation (1) described below.
[0088] In Equation (1), Q denotes a rolling load and is measured by a load cell or computed from the pressures of the screw-down hydraulic cylinders 10a and 10b. Tf and Tb denote an exit side tension and an entry side tension, respectively and are measured by a tension meter (not illustrated) or the like.
[0090] In Equation (2), Dw and Di denote the diameter of the work rolls 2a and 2b and the diameter of the first intermediate rolls 3a and 3b, respectively. δ denotes the work roll offset amount.
[0091] Moreover, a driving tangential force Ft of Equation (1) is obtained by Equation (3) described below.
[0092] In Equation (3), Ti denotes a sum of top and bottom driving torques of the first intermediate rolls 3a and 3b.
[0093] That is, the work roll horizontal force Fwh applied to the work rolls 2a and 2b can be reduced by changing the work roll offset amount δ, and a linear pressure q obtained by dividing the work roll horizontal force Fwh by a length L of the work rolls 2a and 2b can be reduced as illustrated in FIG. 12.
[0094] Thus, work roll deflection ξ caused thereby can be suppressed, and a strip shape defect can consequently be reduced. Thus, the work roll offset amount δ is set to such a value that the work roll deflection ξ is a value in a vicinity of zero or a fixed value being an allowable value.
[0095] The work roll deflection ξ can be obtained as given by Equation (4) from an equation of simple support of a beam.
[0096] In Equation (4), E denotes a modulus of longitudinal elasticity of the work rolls 2a and 2b, and I denotes a geometrical moment of inertia of the work rolls 2a and 2b.
[0097] In the present embodiment, as for a range of the diameter of the work rolls 2a and 2b, such a small diameter that D (work roll diameter)/B (strip width) = 0.08 to 0.16 is particularly suitable. However, the work roll diameter is not limited to the work roll diameter.
[0098] Other configurations and operations are substantially the same configurations and operations of the rolling mill according to the first embodiment, and hence details thereof are omitted.
[0099] Also in the rolling mill according to the third embodiment of the present invention, there are provided effects substantially similar to those of the rolling mill according to the first embodiment described before.
<Fourth Embodiment>
[0100] A description is now given of a rolling mill according to a fourth embodiment of the present invention with reference to FIG. 12 to FIG. 15. FIG. 12 is a front view of an eight-high rolling mill according to the fourth embodiment, FIG. 13 is a diagram for describing intermediate roll offset adjustment, FIG. 14 is a diagram for describing a load applied to the work roll at the time of intermediate roll offset, and FIG. 15 is an explanatory diagram of the deflection of the work roll.
[0101] The fourth embodiment includes, in addition to the third embodiment, a structure which offsets the first intermediate rolls 3a and 3b in the pass direction.
[0102] As illustrated in FIG. 12, the first intermediate rolls 3a and 3b are offset by an offset amount α in the pass direction through pushing and pulling of the hydraulic cylinders 42a, 42b, 42c, 42d, 42e, 42f, 42g, and 42h on the entry side, the exit side, the work side, and the drive side via bearings (not illustrated) and the bearings 4a, 4b, 4c, and 4d.
[0103] For example, by pushing the first intermediate rolls 3a and 3b through the hydraulic cylinders 42a, 42b, 42c, and 42d toward the entry side direction in the pass direction, the first intermediate rolls 3a and 3b are offset by the offset amount α in the pass direction. Simultaneously, the hydraulic cylinders 42e, 42f, 42g, and 42h are pulled by a corresponding amount toward the entry side in the pass direction, and hence the offset amount α of the first intermediate rolls 3a and 3b is maintained.
[0104] A description is now given of a first intermediate roll offset position setting method with reference to FIG. 13 and FIG. 14.
[0105] As described before, in the case in which the first intermediate rolls 3a and 3b are driven, the work roll horizontal force Fwh applied to the work rolls 2a and 2b is obtained by Equation (1) described before.
[0106] Moreover, θiw can be obtained through Equation (5) described below.
where Dw and Di denote the diameter of the work rolls 2a and 2b and the diameter of the first intermediate rolls 3a and 3b, respectively, and α denotes the first intermediate roll offset amount.
[0108] Where, Ti denotes the sum of the top and bottom driving torques of the first intermediate rolls 3a and 3b.
[0109] That is, the work roll horizontal force Fwh applied to the work rolls 2a and 2b can be reduced by changing the first intermediate roll offset amount α, and the linear pressure of work roll horizontal force applied to the work rolls and obtained by dividing the work roll horizontal force Fwh by the length L of the work rolls 2a and 2b q = Fwh/L can be reduced as illustrated in FIG. 15.
[0110] Thus, the work roll deflection ξ caused thereby can be suppressed, and the strip shape defect can consequently be reduced. Thus, the first intermediate roll offset amount α is set to such a value that the work roll deflection ξ is a value in a vicinity of zero or a fixed value being an allowable value.
[0111] Other configurations and operations are substantially the same configurations and operations of the rolling mill according to the first embodiment, and hence details thereof are omitted.
[0112] Also in the rolling mill according to the fourth embodiment of the present invention, there are provided effects substantially similar to those of the rolling mill according to the first embodiment described before.
<Fifth Embodiment>
[0113] A description is now given of a rolling mill according to a fifth embodiment of the present invention.
[0114] In the fifth embodiment, in the eight-high rolling mill according to the third embodiment illustrated in FIG. 8, the one pair of top and bottom first intermediate rolls 3a and 3b have the roll neck portions to which the first intermediate roll bearings 4a, 4b, 4c, and 4d and the first intermediate roll chocks 4e and 4f are attached via bearings (not illustrated).
[0115] Moreover, the arms 32a, 32b, 32c, 32d, 32e, 32f, 32g, and 32h are swingably attached to the first intermediate roll bearings 4a, 4b, 4c, and 4d via the shafts 16a, 16b, 16c, and 16d, and, further, the support bearings 30a, 30b, 30c, 30d, 30e, 30f, 30g, and 30h installed on the work side and the drive side are attached to the arms 32a, 32b, 32c, 32d, 32e, 32f, 32g, and 32h via the shafts 31a, 31b, 31c, 31d, 31e, 31f, 31g, and 31h.
[0116] The support bearings 30a, 30b, 30c, 30d, 30e, 30f, 30g, and 30h and sets of one pair of top and bottom first intermediate rolls 3a and 3b (first cluster arms) to which the first intermediate roll bearings 4a, 4b, 4c, and 4d and the first intermediate roll chocks 4e and 4f are attached can be pulled out toward the work side of the housings 11a and 11b, respectively.
[0117] Meanwhile, in the eight-high rolling mill according to the first embodiment illustrated in FIG. 2, the one pair of top and bottom first intermediate rolls 3a and 3b have the roll neck portions to which the first intermediate roll bearings 4a, 4b, 4c, and 4d and the first intermediate roll chocks 4e and 4f are attached via bearings (not illustrated). Moreover, the first intermediate roll bearings 4a, 4b, 4c, and 4d have the arms 15a, 15b, 15c, and 15d swingably attached thereto via the shafts 16a, 16b, 16c, and 16d, the arms 15a, 15b, 15c, and 15d further have the support bearings 13a, 13b, 13c, 13d, 13e, 13f, 13g, and 13h attached thereto via the shafts 14a, 14b, 14c, 14d, 14e, 14f, 14g, and 14h, and the support bearings 13a, 13b, 13c, 13d, 13e, 13f, 13g, and 13h have the support rolls 12a, 12b, 12c, and 12d attached thereto. The support rolls 12a, 12b, 12c, and 12d support the work rolls 2a and 2b over the full lengths in the strip width direction.
[0118] The support rolls 12a, 12b, 12c, and 12d, support bearings 13a, 13b, 13c, 13d, 13e, 13f, 13g, and 13h, and sets of one pair of top and bottom first intermediate roll 3a and 3b (second cluster arms) to which the first intermediate roll bearings 4a, 4b, 4c, and 4d and the first intermediate roll chocks 4e and 4f are attached can be pulled out toward the work side of the housings 11a and 11b, respectively.
[0119] The first cluster arms are pulled out toward the work side of the housings 11a and 11b, and the second cluster arms are, in place, inserted into the housings 11a and 11b. Moreover, conversely, the second cluster arms are pulled out toward the work side of the housings 11a and 11b, and the first cluster arms are, in place, inserted into the housings 11a and 11b.
[0120] For example, when the first cluster arm is used, the coolant spray headers 35a and 35b can be used, hence the work rolls 2a and 2b can effectively be cooled, and rolling at a higher speed is enabled. Moreover, by switching to the second cluster arm, the work rolls 2a and 2b having a smaller diameter can be used, and hence a harder rolled metal strip can be rolled.
[0121] Other configurations and operations are substantially the same configurations and operations of the rolling mill according to the first embodiment, and hence details thereof are omitted.
[0122] Also in the rolling mill according to the fifth embodiment of the present invention, there are provided effects substantially similar to those of the rolling mill according to the first embodiment described before.
<Sixth Embodiment>
[0123] A description is now given of a rolling mill according to a sixth embodiment of the present invention with reference to FIG. 16 and FIG. 17. FIG. 16 is a front view of an eight-high rolling mill according to the sixth embodiment, and FIG. 17 is a cross-sectional view made in a direction indicated by arrows E-E of FIG. 16.
[0124] In the sixth embodiment, as illustrated in FIG. 16 and FIG. 17, the one pair of the top and bottom work rolls 2a and 2b are rotatably supported on the work side and the drive side on the exit side, and the support bearings 30a, 30b, 30c, and 30d, the shafts 31a, 31b, 31c, and 31d, and the arms 32a, 32b, 32c, and 32d thereof are swingably attached to the first intermediate roll bearings 4a, 4b, 4c, and 4d via the shafts 16a, 16b, 16c, and 16d (third cluster arms).
[0125] Moreover, the one pair of the top and bottom work rolls 2a and 2b are rotatably supported on the entry side by the support rolls 12c and 12d over the full lengths in the strip width direction, the support rolls 12c and 12d are rotatably supported by the support bearings 13e, 13f, 13g, and 13h, and the support bearings 13e, 13f, 13g, and 13h are rotatably supported by the arms 15c and 15d via the shafts 14e, 14f, 14g, and 14h. The arms 15c and 15d are swingably attached to the first intermediate roll bearings 4a, 4b, 4c, and 4d via the shafts 16c and 16d (fourth cluster arms).
[0126] The arms 15c and 15d are supported in the pass direction by the side blocks 17c and 17d. Further, the side blocks 17c and 17d are supported by the housings 11a and 11b via the tapered wedges 18e, 18f, 18g, 18h, 19e, 19e, 19f, 19g, and 19h. The tapered wedges 18e, 18f, 18g, and 18h are pulled and inserted by the hydraulic cylinders 20e, 20f, 20g, and 20h, thereby being able to change thicknesses thereof.
[0127] The arms 32a and 32b are supported in the pass direction by the side block 17a. The arms 32c and 32d are supported in the pass direction by the side block 17b. Further, the side block 17a is supported by the housings 11a and 11b via the tapered wedges 18a, 18b, 19a, and 19b. The side block 17b is supported by the housings 11a and 11b via the tapered wedges 18c, 18d, 19c, and 19d.
[0128] For example, when the tapered wedges 18e, 18f, 18g, and 18h on the entry side are pushed in, the thicknesses thereof increase, the side blocks 17b and 17d move toward the exit side by a corresponding amount, and the work rolls 2a and 2b move toward the exit side by an offset δ via the arms 15c and 15d, the shafts 14e, 14f, 14g, and 14h, the support bearings 13e, 13f, 13g, and 13h, and the support rolls 12c and 12d. Simultaneously on the exit side, when the tapered wedges 18a, 18b, 18c, and 18d on the exit side are pulled out, the thicknesses thereof decrease, the side blocks 17a and 17b move toward the exit side by a corresponding amount, and the support bearings 30a, 30b, 30c, and 30d installed on the work side and the drive side also move toward the exit side by δ via the arms 32a and 32b and the shafts 31a, 31b, 31c, and 31d, thereby supporting the work rolls 2a and 2b.
[0129] In the embodiment, the removing and inserting method for the tapered wedges 18a, 18b, 18c, 18d, 18e, 18e, 18g, and 18h are described, but a motor-driven worm jack method may be employed.
[0130] Moreover, the work rolls 2a and 2b are provided with the cobble guards 33a and 33b on the exit sides of the center portions thereof. Coolant spray headers (not illustrated) may be provided to the cobble guards 33a and 33b. The coolant spray headers cool the work rolls 2a and 2b. Further, for the coolant spray headers, a plurality of zones may be provided in the strip width direction thereof, and a flow rate of the coolant may be variable or may be set to on or off for each of the zones. The strip shape control is thereby enabled.
[0131] For example, in a case in which the strip is locally tight (not stretched) in the strip width direction, by reducing or setting to off the flow rate of the coolant of the coolant spray headers in the zone corresponding to the position of the strip being locally tight in the strip width direction, the cooling of the work rolls 2a and 2b is suppressed by a corresponding amount and the thermal expansion of this portion increases by a corresponding amount to increase the diameter, and thus the state in which the strip shape is tight only in this portion transitions to the state in which the strip shape is stretched, resulting in a flat shape. In the case of the present embodiment, the coolant is sprayed over the roll surface after the rolling on the exit side, and hence effects of the cooling and the shape control are larger than those in a case where the coolant spray headers are provided on the entry side.
[0132] In the case of the present embodiment, even when the work roll offset amount δ of the work rolls 2a and 2b is zero, the work roll horizontal force Fwh applied to the work rolls 2a and 2b illustrated in FIG. 22 is applied only in the entry side direction. Meanwhile, the work rolls 2a and 2b are supported on the entry side by the support rolls 12c and 12d over the full lengths in the strip width direction, and hence the deflections of the work rolls 2a and 2b are extremely slight. Thus, in the case of the present embodiment, the work roll offset amount δ may be zero.
[0133] In the present embodiment, there is described the example in which the support rolls 12c and 12d and the support bearings 13e, 13f, 13g, and 13h supported over the full lengths in the strip width direction are disposed on the entry side, but they may be installed only on the exit side.
[0134] Moreover, in the present embodiment, there is described the example in which, in the one pair of the top and bottom work rolls 2a and 2b, the support rolls 12c and 12d supported over the full lengths in the strip width direction, the support bearings 13e, 13f, 13g, and 13h, the shafts 14e, 14f, 14g, and 14h, and the arms 15c and 15d are swingably attached to the first intermediate roll bearings 4a, 4b, 4c, and 4d via the shafts 16c and 16d, on the entry side, but the support rolls 12c and 12d, the support bearings 13c, 13f, 13g, and 13h, the shafts 14e, 14f, 14g, and 14h, and the arms 15c and 15d may swingably be attached to the side blocks 17c and 17d via the shafts 16c and 16d. Moreover, there may be provided such a structure that the support rolls 12c and 12d and the support bearings 13e, 13f, 13g, and 13h are directly supported by hydraulic cylinders or worm jacks.
[0135] Moreover, there is described the example in which, in the one pair of the top and bottom work rolls 2a and 2b, the support bearings 30a, 30b, 30c, and 30d, the shafts 31a, 31b, 31c, and 31d, and the arms 32a, 32b, 32c, and 32d, which are supported on the work side and the drive side, are swingably attached to the first intermediate roll bearings 4a, 4b, 4c, and 4d via the shafts 16a, 16b, 16c and 16d, on the exit side, but the support bearings 30a, 30b, 30c, and 30d, the shafts 31a, 31b, 31c, and 31d, and the arms 32a, 32b, 32c, and 32d may swingably be attached to the side blocks 17a and 17b via the shafts 16a, 16b, 16c, and 16d.
[0136] Moreover, there may be provided such a structure that the support bearings 30a, 30b, 30c, and 30d are directly supported by hydraulic cylinders or worm jacks.
[0137] Other configurations and operations are substantially the same configurations and operation of the rolling mill according to the first embodiment, and hence details thereof are omitted.
[0138] Also in the rolling mill according to the sixth embodiment of the present invention, there are provided effects substantially similar to those of the rolling mill according to the first embodiment described before.
<Seventh Embodiment>
[0139] A description is now given of a rolling mill according to a seventh embodiment of the present invention with reference to FIG. 18 to FIG. 20. FIG. 18 is a side view of an eight-high rolling mill according to the seventh embodiment, FIG. 19 is a cross-sectional view made in a direction indicated by arrows F-F of FIG. 18, and FIG. 20 is a detailed explanatory view of another eight-high rolling mill according to the seventh embodiment.
[0140] According to the seventh embodiment of the present invention, as illustrated in FIG. 18 to FIG. 20, one pair of top and bottom work rolls 36a and 36b have roll shoulders 36c and 36d, respectively, each in a tapered shape, at roll body end positions point-symmetrical to each other in the up-down axis direction relative to the strip width center of the metal strip 1. The roll shoulders 36c and 36d are provided on the opposite side in the strip width direction from the roll shoulders 3c and 3d of the first intermediate rolls 3a and 3b, respectively.
[0141] The work roll 36a on the top side is supported by a thrust bearing 37a at a work side shaft end and is supported by a thrust bearing 37c at a drive side shaft end. The work roll 36b on the bottom side is supported by a thrust bearing 37b at a work side shaft end and is supported by a thrust bearing 37d at a drive side shaft end.
[0142] The thrust bearings 37a, 37b, 37c, and 37d are rotatably attached to brackets 39a, 39b, 39c, and 39d via shafts 38a, 38b, 38c, and 38d. The brackets 39a, 39b, 39c, and 39d are attached to hydraulic cylinders 40a, 40b, 40c, and 40d.
[0143] Thus, the work roll 36a on the top side is shifted toward the drive side in the roll axis direction through pushing of the hydraulic cylinder 40a and pulling of the hydraulic cylinder 40c. Moreover, the work roll 36a on the top side is shifted toward the work side in the roll axis direction through pulling of the hydraulic cylinder 40a and pushing of the hydraulic cylinder 40c.
[0144] Moreover, the work roll 36b on the bottom side is shifted toward the work side in the roll axis direction through pulling of the hydraulic cylinder 40b and pushing of the hydraulic cylinder 40d. Moreover, the work roll 36b on the bottom side is shifted toward the drive side in the roll axis direction through pushing of the hydraulic cylinder 40b and pulling of the hydraulic cylinder 40d.
[0145] By the hydraulic cylinders 40a, 40b, 40c, and 40d shifting, toward the strip width ends, the roll shoulders 36c and 36d, each in the tapered shape, of the work rolls 36a and 36b point-symmetrical to each other in the up-down direction relative to the strip width center, it is possible to reduce a sharp decrease in strip thickness at the strip ends, which is called edge drop. Note that, in the present invention, "the positions of the roll shoulders 36c and 36d of the work rolls 36a and 36b align with the strip width ends of the metal strip 1, respectively" is not required to mean, in a strict sense, that the positions of the roll shoulders 36c and 36d of the work rolls 36a and 36b align with the strip width ends of the metal strip 1, and it is assumed that the positions of the roll shoulders 36c and 36d of the work rolls 36a and 36b are shifted so as to align with the strip width ends of the metal strip 1 and vicinities thereof in a range of the edge drop being enabled to be generated.
[0146] A description is now given of an edge drop decrease method by shifting the work rolls 36a and 36b having the roll shoulders 36c and 36d each in the tapered shape.
[0147] First, the work rolls 36a and 36b are provided with the roll shoulders 36c and 36d each in the tapered shape, at the positions point-symmetrical in the up-down direction, and a distance between the roll shoulder position and the strip end is denoted by δw as illustrated in FIG. 18.
[0148] Moreover, as illustrated in FIG. 20, there is provided a strip thickness gauge 43 which measures strip thicknesses at one point or a plurality of points in vicinities of the strip ends on the work side and the drive side on the exit side of the rolling mill.
[0149] Then, when each of the strip thicknesses at the one point or the plurality of points in the vicinity of the strip end measured on the work side is thinner than a predetermined strip thickness, the work roll 36a on the top side is shifted toward the drive side being a roll axis narrow width direction. That is, the work roll 36a on the top side is shifted toward such a direction that δw increases.
[0150] Moreover, conversely, when each of the measured strip thicknesses in the vicinity of the strip end is thicker than the predetermined strip thickness, the work roll 36a on the top side is shifted toward the work side being a roll axis wide width direction. That is, the work roll 36a on the top side is shifted toward such a direction that δw decreases.
[0151] Further, in a case in which each of the strip thicknesses at the one point or the plurality of points in the vicinity of the strip end measured on the drive side is different from the predetermined strip thickness, the work roll 36b on the bottom side is similarly shifted so as to make the strip have a predetermined thickness.
[0152] Other configurations and operations are substantially the same configurations and operations of the rolling mill according to the first embodiment, and hence details thereof are omitted.
[0153] Also in the rolling mill according to the seventh embodiment of the present invention, there are provided effects substantially similar to those of the rolling mill according to the first embodiment described before, and further, the work roll shift is available in a small-diameter work roll mill provided with the support rolls and the support bearings, and hence the edge drop can be reduced.
<Eighth Embodiment>
[0154] A description is now given of a rolling mill according to an eighth embodiment of the present invention with reference to FIG. 21 and FIG. 22. FIG. 21 is a detailed explanatory view of an eight-high rolling mill according to the eighth embodiment, and FIG. 22 is a plan view of the eight-high rolling mill according to the eighth embodiment.
[0155] In the eight-high rolling mill according to the eighth embodiment, as illustrated in FIG. 21, load cells 44a, 44b, 44c, 44d, 44e, 44f, 44g, and 44h are installed between the tapered wedged 19a, 19b, 19c, 19d, 19e, 19f, 19g, and 19h and the housing 11a and 11b in the eight-high rolling mill as that according to the third embodiment.
[0156] The horizontal force Fwh applied to the entry side and the exit side of the work roll 2a on the upper side is measured by the load cells 44a, 44b, 44e, and 44f. Moreover, the horizontal force Fwh applied to the entry side and the exit side of the work roll 2b on the bottom side is measured by the load cells 44c, 44d, 44g, and 44h.
[0157] It is assumed that the work roll offset amount δ is such a value that the horizontal force Fwh applied to the entry side and the exit side of the one pair of top and bottom work rolls 2a and 2b is a value in the vicinity of zero or a fixed value being an allowable value. As a result, the work roll deflection ξ can be suppressed and the strip shape defect can consequently be reduced.
[0158] Moreover, in the fourth embodiment, it is assumed that the intermediate roll offset amount α is such a value that the horizontal force Fwh applied to the entry side and the exit side of the one pair of top and bottom work rolls 2a and 2b is a value in the vicinity of zero or a fixed value being an allowable value. Moreover, in place of the direct measurement of the horizontal force Fwh applied to the entry side and the exit side of the one pair of top and bottom work rolls 2a and 2b, the top and bottom driving torques of the one pair of the top and bottom first intermediate rolls 3a and 3b may be measured by a torque meter (not illustrated) and the horizontal force Fwh applied to the entry side and the exit side of the one pair of the top and bottom work rolls 2a and 2b may be computed from Equations (1), (2), and (3).
[0159] Moreover, in FIG. 22, the cobble guards 33a and 33c have gap sensors 41a, 41b, 41c, and 41d installed thereto at the center in the roll axis direction, and horizontal direction gaps of the one pair of the top and bottom work rolls 2a and 2b are measured thereby. As a result, the horizontal direction deflection ξ of the one pair of the top and bottom work rolls 2a and 2b can be known. It is assumed that the work roll offset amount δ or the intermediate roll offset amount α is such a value that the deflection ξ of the one pair of the top and bottom work rolls 2a and 2b is a value in a vicinity of zero or a fixed value being an allowable value. As a result, the strip shape defect can be reduced.
[0160] Other configurations and operations are substantially the same configurations and operations of the rolling mill according to the first embodiment, and hence details thereof are omitted.
[0161] Also in the rolling mill according to the eighth embodiment of the present invention, there are provided effects substantially similar to those of the rolling mill according to the first embodiment described before.
<Ninth Embodiment>
[0162] A description is now given of a tandem rolling mill according to a ninth embodiment of the present invention with reference to FIG. 23. FIG. 23 is an explanatory view of the tandem rolling mill according to the ninth embodiment.
[0163] A tandem rolling mill 1000 according to the present embodiment obtained by disposing a plurality of rolling mills is provided with at least one rolling mill stand described in any one embodiment of the first embodiment to the eighth embodiment and, in FIG. 23, the rolling mill described in the first embodiment is applied, in the tandem rolling mill 1000 provided with a the first rolling mill stand 100, a second rolling mill stand 200, a third rolling mill stand 300, a fourth rolling mill stand 400, and a fifth rolling mill stand 500, to the second rolling mill stand 200, the third rolling mill stand 300, and the fourth rolling mill stand 400. In the tandem rolling mill 1000, the small diameter work rolls can be applied to the second rolling mill stand 200, the third rolling mill stand 300, and the fourth rolling mill stand 400, and hence a strong screw-down for a hard metal strip is enabled.
[0164] Note that the number of rolling mill stands of the tandem rolling mill is not particularly limited and may be two or more. Moreover, it is only required that at least one rolling mill stand is the rolling mill described in any one embodiment of the first embodiment to the eighth embodiment, and all of the rolling mill stands may be the rolling mills according to the first embodiment or the like.
[0165] Other configurations and operations are substantially the same configurations and operations of the rolling mill according to the first embodiment, and hence details thereof are omitted.
[0166] Moreover, in a rolling mill stand on a later stand of the tandem rolling mill, high-speed rolling, favorable strip shape, and favorable water removal on the mill exit side are required, and hence the work roll cooling on the mill entry side of the rolling mill, the installation of the coolant spray headers for the coolant zone control for the strip shape correction, and the installation of the cobble guard on the mill exit side as described in the third embodiment are very effective for this purpose.
[0167] Moreover, in a case in which the work roll shift rolling mill as described in the seventh embodiment is applied to the tandem mill, if the work roll shift rolling mill is applied to all of the rolling mill stands, the edge drop reduction effect is maximum. Particularly, when the work roll shift rolling mill is applied to only the first rolling mill stand 100 and the second rolling mill stand, the strip thicknesses are thicker in the rolling mill stands than those in other rolling mill stands, hence the edge drop reduction effect is higher than that in other rolling mill stands by a corresponding amount, and return on investment is high.
[0168] The tandem rolling mill 1000 according the ninth embodiment of the present invention is provided with at least one rolling mill stand of the rolling mill described in the first embodiment to the eighth embodiment, and hence there are provided effects substantially similar to those of the rolling mills according to the first embodiment and the like described before.
<Others>
[0169] Note that, the present invention is not limited to the embodiments described above and includes various modification examples. The embodiments described above are detailed for an easy-to-understand description of the present invention and the present invention is not necessarily limited to a case including all the described configurations.
[0170] Moreover, a part of a configuration of a certain embodiment can be replaced by a configuration of another embodiment, and, to a configuration of a certain embodiment, a configuration of another embodiment can be added. Moreover, to a part of the configuration of each of the embodiments, another configuration can be added, the part can be deleted, or the part can be replaced by another configuration.
Description of Reference Characters
[0171]
1: Strip
2a, 2b: Work roll
3a, 3b: First intermediate roll
3c, 3d: Roll shoulder (first intermediate roll shoulder)
4a, 4b, 4c, 4d: First intermediate roll bearing
4e, 4f: First intermediate roll chock
5a, 5b: Second intermediate roll
5c, 5d: Roll shoulder (second intermediate roll shoulder)
6a, 6b, 6c, 6d: Second intermediate roll bearing
6e, 6f: Second intermediate roll chock
7a, 7b: Back-up roll
8a, 8b, 8c, 8d: Back-up roll chock
9a, 9b: Pass line adjusting device
10a, 10b: Screw-down hydraulic cylinder
11a, 11b: Housing
12a, 12b, 12c, 12d: Support roll
13a, 13b, 13c, 13d, 13e, 13f, 13g, 13h: Support bearing
14a, 14b, 14c, 14d, 14e, 14f, 14g, 14h: Shaft
15a, 15b, 15c, 15d: Arm
16a, 16b, 16c, 16d: Shaft
17a, 17b, 17c, 17d: Side block (beam)
18a, 18b, 18c, 18d, 18e, 18f, 18g, 18h: Tapered wedge
19a, 19b, 19c, 19d, 19e, 19f, 19g, 19h: Tapered wedge
20a, 20b, 20c, 20d, 20e, 20f, 20g, 20h: Hydraulic cylinder
21a, 21b: Thrust bearing
22a, 22b: Shaft
23a, 23b, 23c, 23d, 24a, 24b, 24c, 24d: Bending cylinder
25a, 25b: Work roll (work roll for six-high rolling mill)
26a, 26b, 26c, 26d: Work roll bearing
27a, 27b: Intermediate roll (intermediate roll for six-high rolling mill)
27c, 27d: Roll shoulder
28a, 28b, 28c, 28d: Intermediate roll bearing
28e, 28f: Roll chock
29a, 29b, 29c, 20d: Bending cylinder
30a, 30b, 30c, 30d, 30e, 30f, 30g, 30h: Support bearing
31a, 31b, 31c, 31d, 31e, 31f, 31g, 31h: Shaft
32a, 32b, 32c, 32d, 32e, 32f, 32g, 32h: Arm
33a, 33b, 33c, 33d: Cobble guard
34a, 34b, 34c, 34d: Hydraulic cylinder
35a, 35b: Coolant spray header
36a, 36b: Work roll
36c, 36d: Roll shoulder (work roll shoulder)
37a, 37b, 37c, 37d: Thrust bearing
38a, 38b, 38c, 38d: Shaft
39a, 39b, 39c, 39d: Bracket
40a, 40b, 40c, 40d: Hydraulic cylinder (work roll shift device)
41a, 41b, 41c, 41d: Gap sensor
42a, 42b, 42c, 42d, 42e, 42f, 42g, 42h: Hydraulic cylinder
43: Strip thickness gauge
44a, 44b, 44c, 44d, 44e, 44f, 44g, 44h: Load cell (detector)
50a, 50b: Shift cylinder (first intermediate roll shift device)
51a, 51b: Shift cylinder (second intermediate roll shift device)
52a, 52b: Shift cylinder
60: Control device
100: First rolling mill stand
200: Second rolling mill stand
300: Third rolling mill stand
400: Fourth rolling mill stand
500: Fifth rolling mill stand
1000: Tandem rolling mill
1. An eight-high rolling mill comprising:
one pair of work rolls that roll a strip;
one pair of first intermediate rolls that have tapered first intermediate roll shoulders at point-symmetrical positions in an up-down axis direction and support the one pair of work rolls;
one pair of second intermediate rolls that have tapered second intermediate roll shoulders at point-symmetrical positions in the up-down axis direction opposite to those of the first intermediate rolls and support the first intermediate rolls;
one pair of back-up rolls that support the second intermediate rolls;
support roll groups or support bearings that are provided on an entry side and/or an exit side in the work rolls;
first intermediate roll shift devices that shift the positions of the first intermediate roll shoulders in an axis direction so as to align with strip width ends of the strip; and
second intermediate roll shift devices that shift the positions of the second intermediate roll shoulders in an axis direction so as to align with the strip width ends of the strip.
2. The eight-high rolling mill according to claim 1, wherein
the work rolls, the first intermediate rolls, and the second intermediate rolls and
one pair of work rolls for a six-high rolling mill that roll the strip and one pair of intermediate rolls for the six-high rolling mill that support the work rolls for the six-high rolling mill
are switchable with each other.
3. The eight-high rolling mill according to claim 2, wherein
a sum of a maximum diameter of the work roll, a maximum diameter of the first intermediate roll, and a maximum diameter of the second intermediate roll is same as or within a range of an error of ±10% of a sum of a maximum diameter of the work roll for the six-high rolling mill and a maximum diameter of the intermediate roll for the six-high rolling mill.
a sum of a maximum diameter of the work roll, a maximum diameter of the first intermediate roll, and a maximum diameter of the second intermediate roll is same as or within a range of an error of ±10% of a sum of a maximum diameter of the work roll for the six-high rolling mill and a maximum diameter of the intermediate roll for the six-high rolling mill.
4. The eight-high rolling mill according to claim 2, wherein
a sum of a minimum diameter of the work roll, a minimum diameter of the first intermediate roll, and a minimum diameter of the second intermediate roll is same as or within a range of an error of ±10% of a sum of a minimum diameter of the work roll for the six-high rolling mill and a minimum diameter of the intermediate roll for the six-high rolling mill.
a sum of a minimum diameter of the work roll, a minimum diameter of the first intermediate roll, and a minimum diameter of the second intermediate roll is same as or within a range of an error of ±10% of a sum of a minimum diameter of the work roll for the six-high rolling mill and a minimum diameter of the intermediate roll for the six-high rolling mill.
5. The eight-high rolling mill according to any one of claims 1 to 4, wherein
the one pair of work rolls are supported across an overall length in a strip width direction on the entry side and the exit side of the strip by the support roll groups.
the one pair of work rolls are supported across an overall length in a strip width direction on the entry side and the exit side of the strip by the support roll groups.
6. The eight-high rolling mill according to claim 5, wherein
the one pair of work rolls are supported across the overall length in the strip width direction on the entry side and the exit side in the work rolls by the support roll groups,
the support roll groups are rotatably installed on arms that are swingably coupled to chocks for the first intermediate rolls, and
pass direction positions of the arms are supported by beams capable of adjusting the pass direction positions.
7. The eight-high rolling mill according to any one of claims 1 to 4, wherein
the eight-high rolling mill further includes coolant spray headers and/or cobble guards disposed in a center portion of the strip in the strip width direction,
the support roll groups or the support bearings support the work rolls on each of a work side and a drive side of the work rolls, and
an offset amount of the work rolls in a pass direction is changed through moving-in and moving-out of the support roll groups or the support bearings on each of the entry side and the exit side in the pass direction, or
an offset amount of the first intermediate rolls in the pass direction is changed through moving-in and moving-out of bearings of the first intermediate rolls on the entry side and the exit side in the pass direction.
8. The eight-high rolling mill according to claim 7, wherein
the support roll groups or the support bearings that provide support on each of the work side and the drive side of the work rolls are rotatably installed on arms that are swingably coupled to first intermediate roll chocks that hold the support roll groups or the support bearings, and
pass direction positions of the arms are adjusted through beams capable of adjusting the pass direction positions to change the offset amount of the work rolls in the pass direction.
9. The eight-high rolling mill according to claim 7, wherein
a first cluster arm provided with the support roll groups or the support bearings that provide support on each of the work side and the drive side of the work rolls, first intermediate roll chocks that hold the support roll groups or the support bearings, and arms that are swingably coupled to the first intermediate roll chocks, and
a second cluster arm provided with second support roll groups that support the work rolls across an overall length in the strip width direction on each of an entry side and an exit side of the work rolls, second first intermediate roll chocks that hold the second support roll groups, and arms that are swingably coupled to the second first intermediate roll chocks
are selectively exchangeable.
10. The eight-high rolling mill according to claim 7, wherein
the eight-high rolling mill includes
a third cluster arm that is, on the entry side or the exit side of the work rolls, provided with the support roll groups or the support bearings that provide support on each of the work side and the drive side of the work rolls, first intermediate roll chocks that hold the support roll groups or the support bearings, and arms that are swingably coupled to the first intermediate roll chocks, and
a fourth cluster arm that is, on the entry side or the exit side of the work rolls, provided with second support roll groups that support the work rolls across an overall length in the strip width direction of the work rolls, second first intermediate roll chocks that hold the second support roll groups, and arms that are swingably coupled to the second first intermediate roll chocks.
11. The eight-high rolling mill according to any one of claims 1 to 4, wherein
the work rolls include tapered work roll shoulders at a point-symmetrical position in the up-down axis direction opposite to those of the first intermediate rolls, and
the eight-high rolling mill further includes work roll shift devices that shift positions of the work roll shoulders in the axis direction such that the positions align with the strip width ends of the strip.
12. The eight-high rolling mill according to any one of claims 1 to 4, wherein
the eight-high rolling mill further includes detectors that detect deflection amounts or horizontal forces of the work rolls, and
an offset amount in the pass direction of the work rolls or the first intermediate rolls is changed on a basis of a detection result of the detectors.
13. A tandem rolling mill formed by arranging a plurality of rolling mills, comprising:
at least one or more rolling mill stands of the eight-high rolling mills according to any one of claim 1 to claim 3.
at least one or more rolling mill stands of the eight-high rolling mills according to any one of claim 1 to claim 3.
14. A modification method for a rolling mill, comprising:
mutually replacing
one pair of work rolls that roll a strip, one pair of first intermediate rolls that have tapered first intermediate roll shoulders at point-symmetrical positions in an up-down axis direction and that support the work rolls, and one pair of second intermediate rolls that have tapered second intermediate roll shoulders at point-symmetrical positions in the up-down axis direction opposite to those of the first intermediate rolls and that support the first intermediate rolls, with
one pair of work rolls for a six-high rolling mill, the one pair of work rolls rolling the strip, and one pair of intermediate rolls for the six-high rolling mill, the one pair of intermediate rolls supporting the work rolls for the six-high rolling mill.
REFERENCES CITED IN THE DESCRIPTION
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.
Patent documents cited in the description