8-stage rolling mill, tandem rolling mill, and method for modifying rolling mill

Abstract

The present invention comprises: one pair of first intermediate rolls 3a, 3b that have tapered roll shoulders 3c, 3d at positions having point symmetry in the vertical axis direction, and that support one pair of work rolls 2a, 2b for rolling a band plate 1; one pair of second intermediate rolls 5a, 5b that have tapered roll shoulders 5c, 5d at positions having point symmetry in the vertical axis direction opposite to those of the first intermediate rolls 3a, 3b, and that support the first intermediate rolls 3a, 3b; one pair of reinforcing rolls 7 that support the second intermediate rolls 5a, 5b; a support roll group 12 or a support bearing 13 provided to the entry side and / or exit side of the work rolls 2a, 2b; a shift cylinder 50 that shifts the positions of the roll shoulders 3c, 3d in the axial direction so as to match the plate-width ends of the band plate 1; and a shift cylinder 51 that shifts the positions of the roll shoulders 5c, 5d in the axial direction so as to match the plate-width ends of the band plate 1. The foregoing makes it possible to roll a hard material more efficiently than conventionally, and yields a band plate having high product quality with few edge drops.

Description

8-high rolling mill, tandem rolling mill, and method for modifying a rolling mill

[0001] The present invention relates to an eight-high rolling mill, a tandem rolling mill, and a method for modifying a rolling mill.

[0002] The patent document 1 describes that at least one rolling stand is provided with a means for changing the shape of the rolling stand, and this convertible rolling stand can take on at least two shapes, each shape corresponding to one production range, while keeping the means for applying the rolling force the same.

[0003] Special Publication No. 2006-505413

[0004] Conventionally, a rolling mill using small diameter work rolls for rolling hard materials has been devised as disclosed in Patent Document 1.

[0005] In the eight-high rolling mill of Patent Document 1, the second intermediate rolls are movable in the axial direction but are not provided with tapered shoulders. Therefore, as shown in region A in Fig. 1 , contact line pressures called harmful contact areas are generated from the second intermediate rolls 105a, 105b to the first intermediate rolls 103a, 103b outside the width of the strip in the strip width direction. Furthermore, as shown in region B in Fig. 1 , contact line pressures called harmful contact areas are also generated from the first intermediate rolls 103a, 103b to the work rolls 102a, 102b outside the width of the strip in the strip width direction.

[0006] These harmful contact areas reduce the effectiveness of the work roll bender and the first intermediate roll bender, resulting in a decrease in shape control capability.Furthermore, these harmful contact areas increase the amount of shape change in response to changes in rolling load, resulting in a decrease in shape stability capability.

[0007] Therefore, in order to solve the above-mentioned problems, an object of the present invention is to provide an eight-high rolling mill, a tandem rolling mill, and a method for modifying a rolling mill, which are capable of rolling hard materials more efficiently than conventional mills and have work roll support rolls suitable for producing high-quality strips with little edge drop.

[0008] The present invention includes a plurality of means for solving the above-mentioned problems. One example of such a rolling mill includes a pair of work rolls for rolling a strip, a pair of first intermediate rolls having first intermediate roll shoulders tapered at positions symmetrical about a point in the up-down axial direction and supporting the work rolls, a pair of second intermediate rolls having second intermediate roll shoulders tapered at positions symmetrical about a point in the up-down axial direction opposite to that of the first intermediate rolls and supporting the first intermediate rolls, a pair of backup rolls supporting the second intermediate rolls, a group of support rolls or support bearings provided on the inlet and / or outlet sides of the work rolls, a first intermediate roll shifting device for shifting the positions of the first intermediate roll shoulders in the axial direction to align with the widthwise ends of the strip, and a second intermediate roll shifting device for shifting the positions of the second intermediate roll shoulders in the axial direction to align with the widthwise ends of the strip.

[0009] According to the present invention, it is possible to roll hard materials more efficiently than in the past, and to obtain a high-quality strip with less edge drop. Objects, configurations, and effects other than those described above will become clear from the following description of the embodiments.

[0010] 16 is an explanatory diagram of the linear pressure distribution of the rolls of a conventional 8-high rolling mill. A front view of an 8-high rolling mill according to the first embodiment. A cross-sectional view taken along the arrows A-A in FIG. 2. A cross-sectional view taken along the arrows B-B in FIG. 2. An explanatory diagram of the linear pressure distribution of the rolls of an 8-high rolling mill according to the first embodiment. A front view of a 6-high rolling mill after switching according to the second embodiment. A cross-sectional view taken along the arrows C-C in FIG. 6. A front view of an 8-high rolling mill according to the third embodiment. A cross-sectional view taken along the arrows D-D in FIG. 8. A diagram explaining work roll offset adjustment of an 8-high rolling mill according to the third embodiment. A diagram explaining the load on the work rolls when the work rolls are offset in an 8-high rolling mill according to the third embodiment. A front view of an 8-high rolling mill according to the fourth embodiment. A diagram explaining intermediate roll offset adjustment of an 8-high rolling mill according to the fourth embodiment. A diagram explaining the load on the work rolls when the intermediate rolls are offset in an 8-high rolling mill according to the fourth embodiment. A diagram explaining work roll deflection of an 8-high rolling mill according to the fourth embodiment. A front view of an 8-high rolling mill according to the sixth embodiment. A cross-sectional view taken along the arrows E-E in FIG. 16. FIG. 19 is a side view of an 8-high rolling mill according to a seventh embodiment. FIG. 20 is a cross-sectional view taken along the line F-F in FIG. 18. FIG. 21 is a detailed explanatory diagram of another 8-high rolling mill according to the seventh embodiment. FIG. 22 is a detailed explanatory diagram of an 8-high rolling mill according to an eighth embodiment. FIG. 23 is a plan view of an 8-high rolling mill according to an eighth embodiment. FIG. 24 is an explanatory diagram of a tandem rolling mill of a ninth embodiment.

[0011] Hereinafter, embodiments of the rolling mill, tandem rolling mill, and rolling mill modification method of the present invention will be described with reference to the drawings. In the drawings used in this specification, identical or corresponding components are designated by the same or similar reference numerals, and repeated description of these components may be omitted.

[0012] First Embodiment A first embodiment of the rolling mill of the present invention will be described with reference to FIGS. 2 to 5. FIG.

[0013] First, the overall configuration of the eight-high rolling mill will be described with reference to Figures 2 to 4. Figure 2 is a front view of the eight-high rolling mill according to the first embodiment, Figure 3 is a cross-sectional view taken along the line A-A in Figure 2, and Figure 4 is a cross-sectional view taken along the line B-B in Figure 2.

[0014] The rolling mill shown in Figures 2 to 4 is an eight-high rolling mill for rolling a strip 1, and includes work rolls 2a, 2b, first intermediate rolls 3a, 3b, second intermediate rolls 5a, 5b, backup rolls 7a, 7b, housings 11a, 11b, thrust bearings 21a, 21b, shafts 22a, 22b, first intermediate roll bearings 4a, 4b, 4c, 4d, first intermediate roll bearing chocks 4e, 4f, bending cylinders 23a, 23b, 23c, 23d, shift cylinders 50a, 50b, second intermediate roll bearings 6a, 6b, 6c, 6d, second intermediate roll bearing chocks 6e, 6f, bending cylinders 24a, 24b, 24c, 24d, shift cylinders 51a, 51b, backup roll bearing chocks 8a, 8b, 8c, 8d, pass line adjustment devices 9a, 9b, pressure reduction hydraulic cylinders 10a, 10b, support rolls 12a, 12b, 12c, 12d, support bearings 13a, 13b, 13c, 13d, 13e, 13f, 13g, 13h, arms 15a, 15b, 15c, 15d, shafts 16a, 16b, 16c, 16d, side blocks 1 7a, 17b, 17c, 17d, tapered wedges 18a, 18b, 18c, 18d, 18e, 18f, 18g, 18h, tapered wedges 19a, 19b, 19c, 19d, 19e, 19f, 19g, 19h, hydraulic cylinders 20a, 20b, 20c, 20d, 20e, 20f, 20g, 20h, control device 60, etc.

[0015] In Figure 2 etc., the symbols "a, b, c, d, e, f, g, h" basically indicate the operating side on the upper exit side of the strip 1 with "a," the driving side on the upper exit side of the strip 1 with "b," the operating side on the lower exit side of the strip 1 with "c," the driving side on the lower exit side of the strip 1 with "d," the operating side on the upper entry side of the strip 1 with "e," the driving side on the upper entry side of the strip 1 with "f," the operating side on the lower entry side of the strip 1 with "g," and the driving side on the lower entry side of the strip 1 with "h."

[0016] In addition, in Figure 2 etc., the symbols "a, b, c, d" basically indicate the upper exit side of the strip 1 as "a", the lower exit side of the strip 1 as "b", the upper entry side of the strip 1 as "c", and the lower entry side of the strip 1 as "d", respectively.

[0017] The pair of upper and lower work rolls 2a, 2b are rolls that roll the strip 1, which is the material to be rolled. Each of the pair of work rolls 2a, 2b is supported in contact with a pair of upper and lower first intermediate rolls 3a, 3b. Furthermore, each of the pair of first intermediate rolls 3a, 3b is supported in contact with a pair of upper and lower second intermediate rolls 5a, 5b. Furthermore, each of the pair of second intermediate rolls 5a, 5b is supported in contact with a pair of upper and lower backup rolls 7a, 7b.

[0018] The upper backup roll 7a is supported by bearings (not shown) and backup roll bearing boxes 8a and 8b, which are supported by housings 11a and 11b via pass line adjustment devices 9a and 9b.

[0019] The pass line adjustment devices 9a and 9b are composed of a worm jack or a tapered wedge and a stepped rocker plate, etc. Here, a load cell (not shown) may be built into the pass line adjustment devices 9a and 9b to measure the rolling load.

[0020] The lower backup roll 7b is supported by bearings (not shown) and backup roll bearing boxes 8c and 8d, and these backup roll bearing boxes 8c and 8d are supported by housings 11a and 11b via pressure-down hydraulic cylinders 10a and 10b.

[0021] The upper first intermediate roll 3a has a tapered roll shoulder 3c at the roll barrel end position, which is point symmetrical with the lower first intermediate roll 3b in the vertical axial direction with respect to the center of the strip width of the strip 1. The lower first intermediate roll 3b has a tapered roll shoulder 3d at the roll barrel end position, which is point symmetrical with the upper first intermediate roll 3a in the vertical axial direction with respect to the center of the strip width of the strip 1.

[0022] Additionally, first intermediate roll bearings 4a and 4c and a first intermediate roll bearing chock 4e are attached to the roll neck portion of the upper first intermediate roll 3a via bearings (not shown). First intermediate roll bearings 4b and 4d and a first intermediate roll bearing chock 4f are attached to the roll neck portion of the lower first intermediate roll 3b via bearings (not shown).

[0023] The upper first intermediate roll 3a is movable in the axial direction by a shift cylinder 50a via a first intermediate roll bearing housing 4e on the drive side. The bearings 4a and 4c are equipped with bending cylinders 23a and 23c that impart roll bending to the first intermediate roll 3a.

[0024] The lower first intermediate roll 3b is movable in the axial direction by a shift cylinder 50b via a first intermediate roll bearing housing 4f on the drive side. The bearings 4b and 4d are equipped with bending cylinders 23b and 23d that impart roll bending to the first intermediate roll 3b.

[0025] These shift cylinders 50a, 50b shift the positions of the roll shoulders 3c, 3d of the first intermediate rolls 3a, 3b in the axial direction so as to align them with the ends of the strip width ends that are closer to the roll shoulders 3c, 3d. In the present invention, "aligning the positions of the roll shoulders 3c, 3d of the first intermediate rolls 3a, 3b with the strip width ends of the strip 1" does not require that the positions of the roll shoulders 3c, 3d of the first intermediate rolls 3a, 3b be strictly aligned with the strip width ends of the strip 1, but includes shifting the positions of the roll shoulders 3c, 3d of the first intermediate rolls 3a, 3b to align them with the strip width ends and their vicinity within a range that allows the removal of areas known as harmful contact portions.

[0026] The upper second intermediate roll 5a has a tapered roll shoulder 5c at a point symmetrical position in the opposite direction of the strip width direction to the upper first intermediate roll 3a, and at a roll barrel end position that is point symmetrical in the vertical axial direction with respect to the strip width center of the strip 1. The lower second intermediate roll 5b has a tapered roll shoulder 5d at a point symmetrical position in the opposite direction of the strip width direction to the lower first intermediate roll 3b, and at a roll barrel end position that is point symmetrical in the vertical axial direction with respect to the strip width center of the strip 1.

[0027] Second intermediate roll bearings 6a and 6c are attached to the roll neck of the upper second intermediate roll 5a via bearings (not shown), and second intermediate roll bearings 6b and 6d are attached to the roll neck of the lower second intermediate roll 5b via bearings (not shown).

[0028] The upper second intermediate roll 5a is movable in the axial direction by a shift cylinder 51a via a second intermediate roll bearing housing 6e on the drive side. Bending cylinders 24a, 24c that impart roll bending are attached to the bearings 5a, 5c of the second intermediate roll 5a. This imparts roll bending to the second intermediate roll 5a.

[0029] The lower second intermediate roll 5b is movable in the axial direction by a shift cylinder 51b via a second intermediate roll bearing housing 6f on the drive side. Bending cylinders 24b, 24d that impart roll bending are attached to the bearings 5b, 5d of the second intermediate roll 5b. This imparts roll bending to the second intermediate roll 5b.

[0030] These shift cylinders 51a, 51b shift the positions of the roll shoulders 5c, 5d of the second intermediate rolls 5a, 5b in the axial direction so as to align them with the ends of the strip width ends that are closer to the roll shoulders 5c, 5d. In the present invention, "aligning the positions of the roll shoulders 5c, 5d of the second intermediate rolls 5a, 5b with the strip width ends of the strip 1" does not necessarily mean that the positions of the roll shoulders 5c, 5d of the second intermediate rolls 5a, 5b must be strictly aligned with the strip width ends of the strip 1, but includes shifting the positions of the roll shoulders 5c, 5d of the second intermediate rolls 5a, 5b to align them with the strip width ends and their vicinity within a range that allows the removal of areas known as harmful contact portions.

[0031] The pair of upper and lower work rolls 2a, 2b are supported at the operation side shaft end by a thrust bearing 21a and at the drive side shaft end by a thrust bearing 21b. The thrust bearings 21a, 21b are rotatably attached to a bracket (not shown) via shafts 22a, 22b.

[0032] The upper work roll 2a is rotatably supported over its entire length in the strip width direction by a support roll 12a on the inlet side of the strip 1, and is rotatably supported over its entire length in the strip width direction by a support roll 12c on the outlet side of the strip 1. The support roll 12a is rotatably supported by support bearings 13a and 13b, and the support roll 12c is rotatably supported by support bearings 13e and 13f.

[0033] The lower work roll 2b is rotatably supported over its entire length in the strip width direction by a support roll 12b on the inlet side of the strip 1, and is rotatably supported over its entire length in the strip width direction by a support roll 12d on the outlet side of the strip 1. The support roll 12b is rotatably supported by support bearings 13c and 13d, and the support roll 12d is rotatably supported by support bearings 13g and 13h.

[0034] The support bearings 13a and 13b are rotatably supported on the arm 15a via shafts 14a and 14b. The support bearings 13c and 13d are rotatably supported on the arm 15b via shafts 14c and 14d. The support bearings 13e and 13f are rotatably supported on the arm 15c via shafts 14e and 14f. The support bearings 13g and 13h are rotatably supported on the arm 15d via shafts 14g and 14h.

[0035] Arm 15a is attached to the first intermediate roll bearing 4a via a shaft 16a so as to be able to swing, and is supported in the pass direction by a side block 17a. Arm 15b is attached to the first intermediate roll bearing 4b via a shaft 16b so as to be able to swing, and is supported in the pass direction by a side block 17b. Arm 15c is attached to the first intermediate roll bearing 4c via a shaft 16c so as to be able to swing, and is supported in the pass direction by a side block 17c. Arm 15d is attached to the first intermediate roll bearing 4d via a shaft 16d so as to be able to swing, and is supported in the pass direction by a side block 17d.

[0036] As a result, the pass direction positions of the arms 15a, 15b, 15c, and 15d can be adjusted using the pass direction position adjustable side blocks 17a, 17b, 17c, and 17d, so that the offset amount in the pass direction of the work rolls 2a and 2b can be changed.

[0037] Furthermore, side block 17a is supported by housings 11a and 11b via tapered wedges 18a, 18b, 19a, and 19b. Side block 17b is supported by housings 11a and 11b via tapered wedges 18c, 18d, 19c, and 19d. Side block 17c is supported by housings 11a and 11b via tapered wedges 18e, 18f, 19e, and 19f. Side block 17d is supported by housings 11a and 11b via tapered wedges 18g, 18h, 19g, and 19h.

[0038] Tapered wedges 18a and 18b can be inserted and removed by hydraulic cylinders 20a and 20b, thereby changing their thickness. Tapered wedges 18c and 18d can be inserted and removed by hydraulic cylinders 20c and 20d, thereby changing their thickness. Tapered wedges 18e and 18f can be inserted and removed by hydraulic cylinders 20e and 20f, thereby changing their thickness. Tapered wedges 18g and 18h ​​can be inserted and removed by hydraulic cylinders 20g and 20h, thereby changing their thickness.

[0039] For example, when changing from a large-diameter work roll to a small-diameter work roll, the tapered wedges 18a, 18b, 18c, 18d, 18e, 18f, 18g, and 18h ​​are pushed in, increasing their thickness, and the side blocks 17a, 17b, 17c, and 17d move toward the inside of the mill accordingly. Therefore, the support rolls 12a, 12b, 12c, and 12d are also closed toward the inside of the mill via the arms 15a, 15b, 15c, and 15d, shafts 16a, 16b, 16c, and 16d, and support bearings 13a, 13b, 13c, 13d, 13e, 13f, 13g, and 13h, allowing them to come into contact with and support the small-diameter work roll.

[0040] Conversely, when changing from a small-diameter work roll to a large-diameter work roll, the tapered wedges 18a, 18b, 18c, 18d are removed, reducing the thickness, and the side blocks 17a, 17b, 17c, 17d move outward by that amount. Therefore, the support rolls 12a, 12c, 12d also open outward via the arms 15a, 15b, 15c, 15d, shafts 16a, 16b, 16c, 16d, and support bearings 13a, 13b, 13c, 13d, 13e, 13f, 13g, 13h, so that they can come into contact with and support the large-diameter work roll.

[0041] In this embodiment, the tapered wedges 18a, 18b, 18c, 18d, 18e, 18f, 18g, and 18h ​​are moved in and out by a motor-driven worm jack.

[0042] The control device 60 is a device that controls the operation of the above-mentioned various devices in the rolling mill, including the above-mentioned shift cylinders 50a, 50b, 51a, and 51b. This control device 60 can be configured as a computer having a monitor such as a liquid crystal display (to be described later), an input device, a storage device, a CPU, a memory, etc., and may be configured as a single computer or as separate computers, and is not particularly limited.

[0043] The control of the operation of each device by the control device 60 is executed based on various programs recorded in the storage device. The control processing of the operation executed by the control device 60 may be integrated into one program, or may be separated into multiple programs, or may be a combination of these. Furthermore, some or all of the programs may be realized by dedicated hardware or may be modularized.

[0044] In addition, although an example has been shown 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 attached to the first intermediate roll bearings 4a, 4b, 4c, and 4d via the shafts 16a, 16b, 16c, and 16d so as to be able to swing, The support rolls 12a, 12b, 12c, 12d, support bearings 13a, 13b, 13c, 13d, 13e, 13f, 13g, 13h, shafts 14a, 14b, 14c, 14d, 14e, 14f, 14g, 14h, and arms 15a, 15b, 15c, 15d may be attached to side blocks 17a, 17b, 17c, 17d via shafts 16a, 16b, 16c, 16d so as to be swingable. Alternatively, the support rolls 12a, 12b, 12c, 12d, and support bearings 13a, 13b, 13c, 13d, 13e, 13f, 13g, 13h may be directly supported by hydraulic cylinders or worm jacks.

[0045] Next, the effects of this embodiment will be described.

[0046] The rolling mill of the first embodiment of the present invention described above comprises a pair of work rolls 2a, 2b for rolling a strip 1, a pair of first intermediate rolls 3a, 3b having tapered roll shoulders 3c, 3d at positions symmetrical about a point in the vertical axial direction and supporting the work rolls 2a, 2b, a pair of second intermediate rolls 5a, 5b having tapered roll shoulders 5c, 5d at positions symmetrical about a point in the vertical axial direction opposite to the first intermediate rolls 3a, 3b and supporting the first intermediate rolls 3a, 3b, and a pair of reinforcing rolls 5c, 5d supporting the second intermediate rolls 5a, 5b. a group of support rolls 12a, 12b, 12c, 12d or support bearings 13a, 13b, 13c, 13d, 13e, 13f, 13g, 13h provided on the entry side and / or exit side of the work rolls 2a, 2b; shift cylinders 50a, 50b for shifting the positions of the roll shoulders 3c, 3d in the axial direction to align them with the width ends of the strip 1; and shift cylinders 51a, 51b for shifting the positions of the roll shoulders 5c, 5d in the axial direction to align them with the width ends of the strip 1.

[0047] According to this configuration, as shown in region C in Figure 5, by shifting the tapered shoulder positions of the first intermediate rolls 3a, 3b to align them with the vicinity of the strip width ends at positions symmetrical about the upper and lower points, it is possible to remove the linear contact pressure from the first intermediate rolls 3a, 3b outside the strip width, which is called the harmful contact area, on the side where the tapered shoulder positions of the first intermediate rolls 3a, 3b are located, to the work rolls 2a, 2b.

[0048] Furthermore, as shown in region D in Fig. 5, by shifting the tapered shoulder positions of the second intermediate rolls 5a, 5b at point-symmetric positions in the opposite strip width direction to the first intermediate rolls 3a, 3b so that they are aligned with the strip width ends at positions point-symmetric above and below, it is possible to eliminate the contact line pressure from the second intermediate rolls 5a, 5b outside the strip width to the first intermediate rolls 3a, 3b, which is called harmful contact areas. This makes it possible to eliminate harmful contact areas above and below the roll arrangement on the operation side and drive side of the strip width.

[0049] As a result, the effectiveness of the work roll bender and the first intermediate roll bender is increased, improving shape control capability. Furthermore, the amount of shape change in response to changes in rolling load is reduced, improving shape stability capability. For example, this rolling mill is suitable for producing high-quality strips with little sudden thickness reduction at the strip edges, known as edge drop. Such a rolling mill of the present invention is suitable for producing high-productivity and high-quality strips when the strip 1 is made of a hard material.

[0050] Second Embodiment A rolling mill and a method of modifying a rolling mill according to a second embodiment of the present invention will be described with reference to Figures 6 and 7. Figure 6 is a front view of a six-high rolling mill after switching according to the second embodiment of the present invention, and Figure 7 is a cross-sectional view taken along the line CC in Figure 6.

[0051] In the six-high rolling mill shown in Figure 6, the strip 1, which is the material to be rolled, is rolled by a pair of upper and lower work rolls 25a, 25b. Each of the pair of upper and lower work rolls 25a, 25b is supported in contact with a pair of upper and lower intermediate rolls 27a, 27b. Each of the pair of upper and lower intermediate rolls 27a, 27b is supported in contact with a pair of upper and lower backup rolls 7a, 7b.

[0052] The upper work roll 25a is rotatably attached to work roll bearings 26a and 26c via bearings (not shown) on its operating and driving sides, while the lower work roll 25b is rotatably attached to work roll bearings 26b and 26d via bearings (not shown) on its operating and driving sides.

[0053] Each of the work roll bearings 26a, 26c is provided with a bending cylinder 29a, 29c that imparts roll bending to the work roll 25a. Also, each of the work roll bearings 26b, 26d is provided with a bending cylinder 29b, 29d that imparts roll bending to the work roll 25b.

[0054] The upper intermediate roll 27a has a tapered roll shoulder 27c at the end of the roll barrel, which is vertically symmetrical with respect to the lower intermediate roll 27b with respect to the center of the strip width of the strip 1. The upper intermediate roll 27a is movable in the axial direction by a shift cylinder 52a via an intermediate roll bearing box 28e on the drive side.

[0055] The lower intermediate roll 27b has a tapered roll shoulder 27d at the end of the roll barrel, which is vertically symmetrical with respect to the upper intermediate roll 27a with respect to the center of the strip width of the strip 1. The lower intermediate roll 27b is movable in the axial direction by a shift cylinder 52b via an intermediate roll bearing box 28f on the drive side.

[0056] The bearings 28a and 28c are respectively provided with bending cylinders 24a and 24c for imparting roll bending to the intermediate roll 27a, while the bearings 28b and 28d are respectively provided with bending cylinders 24b and 24d for imparting roll bending to the intermediate roll 27b.

[0057] In this embodiment, the pair of upper and lower work rolls 25a, 25b with work roll bearings 26a, 26b, 26c, 26d and the pair of upper and lower intermediate rolls 27a, 27b with intermediate roll bearings 28a, 28b, 28c, 28d are extracted to the operation side of the housings 11a, 11b, respectively, and instead the work rolls 2a, 2b, the pair of upper and lower first intermediate rolls 3a, 3b with first intermediate roll bearings 4a, 4b, 4c, 4d, and the pair of upper and lower second intermediate rolls 5a, 5b with second intermediate roll bearings 6a, 6b, 6c, 6d of the 8-high rolling mill described in the first embodiment are inserted into the housings 11a, 11b, thereby making it possible to switch between a 6-high rolling mill and an 8-high rolling mill.

[0058] For example, when rolling hard materials, it is possible to use smaller diameter work rolls 2a, 2b of an eight-high rolling mill that is suitable for rolling hard materials, and when rolling soft materials, it is possible to switch to a six-high rolling mill and use medium diameter work rolls 25a, 25b that are suitable for rolling soft materials.

[0059] Here, Patent Document 1 describes that when switching between a six-high rolling mill and an eight-high rolling mill, the sum of the work roll diameter and the first intermediate roll diameter of the eight-high rolling mill is set to be approximately the same as the work roll diameter of the six-high rolling mill. However, this poses a problem in that the work roll diameter of the six-high rolling mill becomes large, reducing the effect of the small diameter work rolls of the six-high rolling mill.

[0060] For this reason, it is desirable that the sum of the maximum diameters of the work rolls 2a, 2b, the first intermediate rolls 3a, 3b, and the second intermediate rolls 5a, 5b of the eight-high rolling mill be the same as the sum of the maximum diameters of the work rolls 25a, 25b and the intermediate rolls 27a, 27b of the six-high rolling mill, or within a range of error of ±10%, more preferably within a range of error of ±5%, and even more preferably within a range of error of ±2%.

[0061] Alternatively, or in addition, it is desirable that the sum of the minimum diameters of the work rolls 2a, 2b, the first intermediate rolls 3a, 3b, and the second intermediate rolls 5a, 5b of the eight-high rolling mill be the same as the sum of the minimum diameters of the work rolls 25a, 25b and the intermediate rolls 27a, 27b of the six-high rolling mill, or within a margin of error of ±10%, more preferably within a margin of error of ±5%, and even more preferably within a margin of error of ±2%.

[0062] The other configurations and operations of the rolling mill are substantially the same as those of the rolling mill of the first embodiment described above, and details thereof will be omitted.

[0063] The rolling mill according to the second embodiment of the present invention also provides substantially the same effects as those of the rolling mill according to the first embodiment described above.

[0064] Furthermore, according to the method for retrofitting a rolling mill of the second embodiment of the present invention, the combination of the work rolls 2a, 2b, the first intermediate rolls 3a, 3b, and the second intermediate rolls 5a, 5b of an eight-high rolling mill can be easily replaced with the combination of the work rolls 25a, 25b and the intermediate rolls 27a, 27b of a six-high rolling mill without making any major adjustments. This makes the inner surface heights of the housings of both rolls approximately the same, which is particularly advantageous when retrofitting. Furthermore, the diameters of the work rolls 25a, 25b of the six-high rolling mill can be reduced, making it possible to take advantage of the small diameter of the work rolls 25a, 25b of the six-high rolling mill.

[0065] Furthermore, by making the sum of the maximum or minimum diameters of the work rolls 2a, 2b, first intermediate rolls 3a, 3b, and second intermediate rolls 5a, 5b of the eight-high rolling mill the same as the sum of the maximum or minimum diameters of the work rolls 25a, 25b and intermediate rolls 27a, 27b of the six-high rolling mill, or by making the sum of the maximum or minimum diameters within an error of ±10%, the inner surface heights of the housings of both can be made the same, which is particularly advantageous when converting a six-high rolling mill into an eight-high / six-high switchable mill.

[0066] <Third embodiment> A rolling mill according to a third embodiment of the present invention will be described with reference to Figures 8 to 11. Figure 8 is a front view of an eight-high rolling mill according to the third embodiment, and Figure 9 is a cross-sectional view taken along the line DD in Figure 8.

[0067] As shown in FIGS. 8 and 9, the rolling mill of the third embodiment is an eight-high rolling mill, and a strip 1, which is the material to be rolled, is rolled by a pair of upper and lower work rolls 2a, 2b.

[0068] The work roll 2a is rotatably supported by support bearings 30e, 30f installed on the operation side and drive side at the horizontal entry side, and by support bearings 30a, 30b installed on the operation side and drive side at the horizontal exit side. The work roll 2b is rotatably supported by support bearings 30g, 30h installed on the operation side and drive side at the horizontal entry side, and by support bearings 30c, 30d installed on the operation side and drive side at the horizontal exit side.

[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 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 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 shaft 16c. The support bearings 30g and 30h are rotatably supported by arms 32g and 32h via shafts 31g and 31h. The arms 32g and 32h are attached to the first intermediate roll bearing 4d via a shaft 16d so as to be able to swing.

[0070] Arms 32a and 32b are supported in the pass direction by side block 17a. Arms 32c and 32d are supported in the pass direction by side block 17b. Arms 32e and 32f are supported in the pass direction by side block 17c. Arms 32g and 32h are supported in the pass direction by side block 17d.

[0071] As a result, the pass direction positions of the arms 15a, 15b, 15c, and 15d can be adjusted using the pass direction position adjustable side blocks 17a, 17b, 17c, and 17d, so that the offset amount in the pass direction of the work rolls 2a and 2b can be changed.

[0072] Furthermore, side block 17a is supported by housings 11a and 11b via tapered wedges 18a, 18b, 19a, and 19b. Side block 17b is supported by housings 11a and 11b via tapered wedges 18c, 18d, 19c, and 19d. Side block 17c is supported by housings 11a and 11b via tapered wedges 18e, 18f, 19e, and 19f. Side block 17d is supported by housings 11a and 11b via tapered wedges 18g, 18h, 19g, and 19h.

[0073] Tapered wedges 18a and 18b can be inserted and removed by hydraulic cylinders 20a and 20b, thereby changing their thickness. Tapered wedges 18c and 18d can be inserted and removed by hydraulic cylinders 20c and 20d, thereby changing their thickness. Tapered wedges 18e and 18f can be inserted and removed by hydraulic cylinders 20e and 20f, thereby changing their thickness. Tapered wedges 18g and 18h ​​can be inserted and removed by hydraulic cylinders 20g and 20h, thereby changing their thickness.

[0074] For example, when the tapered wedges 18e, 18f, 18g, and 18h ​​on the entry side are pressed in, their thickness increases, and the side blocks 17b and 17d move to the exit side by that amount, and the work rolls 2a and 2b move to the exit side by the 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] At the same time, when the tapered wedges 18a, 18b, 18c, and 18d on the delivery side are removed, their thickness becomes thinner, and the side blocks 17a and 17c move to the delivery side by that amount, and the support bearings 30a, 30b, 30c, and 30d also move by δ to the delivery side via the arms 32a, 32b, 32c, and 32d and the shafts 31a, 31b, 31c, and 31d, and support the work rolls 2a and 2b.

[0076] In this example, the tapered wedges 18a, 18b, 18c, 18d, 18e, 18f, 18g, and 18h ​​are moved in and out by a motor-driven worm jack.

[0077] The work roll 2a is provided with a cobble guard 33c on the entry side of its central portion, and a coolant spray header 35a is provided on 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 its central portion, and a coolant spray header 35b is provided on the cobble guard 33d. The coolant spray header 35b cools and lubricates the work roll 2b.

[0078] Furthermore, the coolant spray headers 35a, 35b may be provided with a plurality of zones in the strip width direction, and the coolant flow rate may be varied or turned on / off for each zone, thereby enabling strip shape control.

[0079] For example, if the plate is locally stretched (not stretched) in the plate width direction, the flow rate of the coolant in the zone at the same position in the plate width direction of the coolant spray headers 35a, 35b can be reduced or turned off to suppress the cooling of the work rolls 2a, 2b at that point, which increases the thermal expansion of that part and increases the diameter.As a result, the shape of the plate changes from a stretched state in that part to a stretched state, resulting in a flat shape.

[0080] The cobble guards 33c and 33d can be retracted by hydraulic cylinders 34c and 34d fixed to the housings 11a and 11b when the first intermediate rolls 3a and 3b are replaced.

[0081] In this embodiment, the coolant spray headers 35a, 35b are installed on the inlet side, but they may be installed on the outlet side or on both the inlet and outlet sides.

[0082] Furthermore, the application of multiple zones in the width direction of the coolant spray header 35a to control the strip shape is effective only on the upper side. If this is also provided on the lower side, the effect will be even greater.

[0083] In addition, cobble guards 33a, 33b are provided on the central exit side of the work rolls 2a, 2b to prevent broken pieces of plate from getting caught in the rolls when the plate breaks at the mill exit side and to prevent coolant from falling onto the plate for the purpose of draining water.

[0084] In this example, 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 attached to the first intermediate roll bearings 4a, 4b, 4c, and 4d via the shafts 16a, 16b, 16c, and 16d so as to be able to swing. However, these support bearings 30a, 30b, 30c, 30d, 30e, 30f, 30g, 30h, shafts 31a, 31b, 31c, 31d, 31e, 31f, 31g, 31h, and arms 32a, 32b, 32c, 32d, 32e, 32f, 32g, 32h may be attached to side blocks 17a, 17b, 17c, 17d via shafts 16a, 16b, 16c, 16d so as to be swingable. Also, a structure may be adopted in which the support bearings 30a, 30b, 30c, 30d, 30e, 30f, 30g, 30h are directly supported by hydraulic cylinders or worm jacks.

[0085] Furthermore, in this embodiment, the cobble guards 33c, 33d and the cobble guards 33a, 33b to which the coolant spray headers 35a, 35b are attached can be retracted by hydraulic cylinders 34a, 34b, 34c, 34d fixed to the housings 11a, 11b, but the cobble guards 33c, 33d and the cobble guards 33a, 33b to which the coolant spray headers 35a, 35b are attached may also be mounted on the first intermediate roll bearings 4a, 4b, 4c, 4d.

[0086] A method for setting the offset position of the work rolls will now be described with reference to Figures 10 and 11. Figure 10 is a diagram for explaining work roll offset adjustment, and Figure 11 is a diagram for explaining the load applied to the work rolls when the work rolls are offset.

[0087] First, when the first intermediate rolls 3a, 3b are driven, the horizontal work roll force Fwh acting on the work rolls 2a, 2b can be calculated by the following formula (1).

[0088] Fwh=Ft-Qtanθiw-(Tf-Tb) / 2 (1) In formula (1), Q represents the rolling load and is measured by a load cell or calculated from the pressure of the rolling hydraulic cylinders 10a, 10b. Tf and Tb represent the delivery tension and entry tension, respectively, and are measured by a tension meter (not shown) or the like.

[0089] Moreover, θiw in equation (1) is calculated from equation (2) shown below.

[0090] Sin θiw=δ / ((Di+Dw) / 2)) (2) In equation (2), Dw and Di represent the diameters of the work rolls 2a and 2b and the first intermediate rolls 3a and 3b, respectively. δ represents the work roll offset amount.

[0091] The driving tangential force Ft in the formula (1) is calculated by the following formula (3).

[0092] Ft=(Ti / 2) / (Di / 2) (3) In the formula (3), Ti represents the total value of the vertical driving torque of the first intermediate rolls 3a and 3b.

[0093] That is, by changing the work roll offset amount δ, the work roll horizontal force Fwh acting on the work rolls 2a, 2b can be reduced, and as shown in FIG. 12, the linear pressure q obtained by dividing the work roll horizontal force Fwh by the length L of the work rolls 2a, 2b can be reduced.

[0094] Therefore, the work roll offset amount δ is set to a value that makes the work roll deflection ξ close to 0 or a constant value that is within the allowable range.

[0095] The work roll deflection ξ can be calculated from the following equation (4) based on the equation for simple support of the beam.

[0096] ξ = (5 q L ４ ) / (384·E·I) (4) In equation (4), E represents the modulus of longitudinal elasticity of the work rolls 2a, 2b, and I represents the second moment of area of ​​the work rolls 2a, 2b.

[0097] In this embodiment, the diameter range of the work rolls 2a, 2b is particularly preferably small, such that D (work roll diameter) / B (plate width) = 0.08 to 0.16, although the work roll diameter is not limited to this range.

[0098] The other configurations and operations are substantially the same as those of the rolling mill of the first embodiment described above, and details thereof will be omitted.

[0099] The rolling mill according to the third embodiment of the present invention also provides substantially the same effects as those of the rolling mill according to the first embodiment described above.

[0100] <Fourth embodiment> A rolling mill according to a fourth embodiment of the present invention will be described with reference to Figures 12 to 15. Figure 12 is a front view of an eight-high rolling mill according to this fourth embodiment, Figure 13 is a diagram for explaining intermediate roll offset adjustment, Figure 14 is a diagram for explaining the load acting on the work rolls when the intermediate rolls are offset, and Figure 15 is a diagram for explaining the deflection of the work rolls.

[0101] In addition to the third embodiment, the fourth embodiment has a structure in which the first intermediate rolls 3a and 3b are offset in the pass direction.

[0102] As shown in FIG. 12, the first intermediate rolls 3a and 3b are offset in the pass direction by an offset amount α via bearings (not shown) and bearings 4a, 4b, 4c, and 4d by pushing and pulling hydraulic cylinders 42a, 42b, 42c, 42d, 42e, 42f, 42g, and 42h on the entry side, exit side, operation side, and drive side.

[0103] For example, by pushing the first intermediate rolls 3a and 3b toward the entrance side of the pass direction with the hydraulic cylinders 42a, 42b, 42c, and 42d, the first intermediate rolls 3a and 3b are offset in the pass direction by the offset amount α. At the same time, the hydraulic cylinders 42e, 42f, 42g, and 42h are pulled toward the entrance side of the pass direction by that amount, and the first intermediate rolls 3a and 3b are maintained at the offset amount α.

[0104] Here, a method for setting the offset position of the first intermediate roll will be described with reference to FIGS.

[0105] As described above, when the first intermediate rolls 3a, 3b are driven, the horizontal work roll force Fwh acting on the work rolls 2a, 2b is determined by the above-mentioned formula (1).

[0106] Moreover, θiw can be calculated by the following equation (5).

[0107] Sin θiw=α / ((Di+Dw) / 2)) (5) Here, Dw and Di represent the diameters of the work rolls 2a and 2b and the first intermediate rolls 3a and 3b, respectively, and α represents the first intermediate roll offset amount.

[0108] The driving tangential force Ft is calculated by the following formula (6).

[0109] Ft=(Ti / 2) / (Di / 2) (6) where Ti represents the total value of the vertical driving torque of the first intermediate rolls 3a and 3b.

[0110] That is, by changing the first intermediate roll offset amount α, the work roll horizontal force Fwh acting on the work rolls 2a, 2b can be reduced, and as shown in FIG. 15, the work roll horizontal force linear pressure q acting on the work rolls, calculated by dividing the work roll horizontal force Fwh by the length L of the work rolls 2a, 2b, q=Fwh / L, can be reduced.

[0111] Therefore, the resulting work roll deflection ξ can be suppressed, and as a result, the sheet shape defects can be reduced. Therefore, the first intermediate roll offset amount α is set to a value that makes the work roll deflection ξ a constant value close to 0 or an allowable value.

[0112] The other configurations and operations are substantially the same as those of the rolling mill of the first embodiment described above, and details thereof will be omitted.

[0113] The rolling mill according to the fourth embodiment of the present invention also provides substantially the same effects as those of the rolling mill according to the first embodiment described above.

[0114] Fifth Embodiment A rolling mill according to a fifth embodiment of the present invention will be described.

[0115] In the fifth embodiment, in the eight-high rolling mill of the third embodiment as shown in FIG. 8, first intermediate roll bearings 4a, 4b, 4c, 4d and first intermediate roll bearing housings 4e, 4f are attached to the roll necks of a pair of upper and lower first intermediate rolls 3a, 3b via bearings (not shown).

[0116] Furthermore, arms 32a, 32b, 32c, 32d, 32e, 32f, 32g, and 32h are attached to the first intermediate roll bearings 4a, 4b, 4c, and 4d via shafts 16a, 16b, 16c, and 16d so as to be able to swing, and further support bearings 30a, 30b, 30c, 30d, 30e, 30f, 30g, and 30h installed on the operation side and the drive side are attached to the arms 32a, 32b, 32c, 32d, 32e, 32f, 32g, and 32h via shafts 31a, 31b, 31c, 31d, 31e, 31f, 31g, and 31h.

[0117] These support bearings 30a, 30b, 30c, 30d, 30e, 30f, 30g, 30h, first intermediate roll bearings 4a, 4b, 4c, 4d, and first intermediate roll bearing housings 4e, 4f, and a pair of upper and lower first intermediate rolls 3a, 3b (first cluster arms) with these support bearings 30a, 30b, 30c, 30d, 30e, 30f, 30g, 30h, first intermediate roll bearings 4a, 4b, 4c, 4d, and first intermediate roll bearing housings 4e, 4f, can be removed to the operating side of the housings 11a, 11b, respectively.

[0118] On the other hand, in the eight-high rolling mill of the first embodiment as shown in FIG. 2, first intermediate roll bearings 4a, 4b, 4c, 4d and first intermediate roll bearing housings 4e, 4f are attached to the roll necks of the pair of upper and lower first intermediate rolls 3a, 3b via bearings (not shown). Furthermore, arms 15a, 15b, 15c, and 15d are attached to the first intermediate roll bearings 4a, 4b, 4c, and 4d via shafts 16a, 16b, 16c, and 16d so as to be able to swing, and further support bearings 13a, 13b, 13c, 13d, 13e, 13f, 13g, and 13h are attached to the arms 15a, 15b, 15c, and 15d via shafts 14a, 14b, 14c, 14d, 14e, 14f, 14g, and 14h, and support rolls 12a, 12b, 12c, and 12d are attached to the support bearings 13a, 13b, 13c, 13d, 13e, 13f, 13g, and 13h. These support rolls 12a, 12b, 12c, and 12d support the work rolls 2a and 2b over the entire length in the strip width direction.

[0119] These support rolls 12a, 12b, 12c, 12d, support bearings 13a, 13b, 13c, 13d, 13e, 13f, 13g, 13h, first intermediate roll bearings 4a, 4b, 4c, 4d, and upper and lower pairs of first intermediate rolls 3a, 3b (second cluster arms) with first intermediate roll bearing housings 4e, 4f can be removed to the operation side of the housings 11a, 11b, respectively.

[0120] The first cluster arm is pulled out to the operation side of the housings 11a and 11b, and the second cluster arm is inserted into the housings 11a and 11b instead. Conversely, the second cluster arm is pulled out to the operation side of the housings 11a and 11b, and the first cluster arm is inserted into the housings 11a and 11b instead.

[0121] For example, when the first cluster arm is used, the coolant spray headers 35a and 35b can be used, allowing for effective cooling of the work rolls 2a and 2b, enabling higher speed rolling. Furthermore, switching to the second cluster arm allows for the use of smaller diameter work rolls 2a and 2b, making it possible to roll harder materials.

[0122] The other configurations and operations are substantially the same as those of the rolling mill of the first embodiment described above, and details thereof will be omitted.

[0123] The rolling mill according to the fifth embodiment of the present invention also provides substantially the same effects as those of the rolling mill according to the first embodiment described above.

[0124] Sixth Embodiment A rolling mill according to a sixth embodiment of the present invention will be described with reference to Figures 16 and 17. Figure 16 is a front view of an eight-high rolling mill according to the sixth embodiment, and Figure 17 is a cross-sectional view taken along the line E-E in Figure 16.

[0125] In the sixth embodiment, as shown in FIGS. 16 and 17, a pair of upper and lower work rolls 2a, 2b are rotatably supported on the operation side and the drive side at the outlet sides thereof, and their support bearings 30a, 30b, 30c, 30d, shafts 31a, 31b, 31c, 31d, and arms 32a, 32b, 32c, 32d are attached so as to be able to swing to first intermediate roll bearings 4a, 4b, 4c, 4d via shafts 16a, 16b, 16c, 16d (third cluster arms).

[0126] The pair of upper and lower work rolls 2a, 2b are rotatably supported on their entry sides by support rolls 12c, 12d over their entire length in the strip width direction, and the support rolls 12c, 12d are rotatably supported by support bearings 13e, 13f, 13g, 13h, which are rotatably supported by arms 15c, 15d via shafts 14e, 14f, 14g, 14h. The arms 15c, 15d are attached to first intermediate roll bearings 4a, 4b, 4c, 4d via shafts 16c, 16d so as to be swingable (fourth cluster arms).

[0127] The arms 15c and 15d are supported in the path direction by side blocks 17c and 17d. The side blocks 17c and 17d are further supported by the housings 11a and 11b via tapered wedges 18e, 18f, 18g, 18h, 19e, 19f, 19g, and 19h. The tapered wedges 18e, 18f, 18g, and 18h ​​can be inserted and removed by hydraulic cylinders 20e, 20f, 20g, and 20h, allowing their thickness to be changed.

[0128] The arms 32a and 32b are supported in the path direction by the side block 17a. The arms 32c and 32d are supported in the path direction by the side block 17b. Furthermore, the side block 17a is supported by the housings 11a and 11b via tapered wedges 18a, 18b, 19a, and 19b. The side block 17b is supported by the housings 11a and 11b via tapered wedges 18c, 18d, 19c, and 19d.

[0129] For example, when the entry-side tapered wedges 18e, 18f, 18g, and 18h ​​are pushed in, their thickness increases, causing the side blocks 17b and 17d to move to the delivery side by that amount, and the work rolls 2a and 2b move toward the delivery side by an offset δ via the arms 15c and 15d, shafts 14e, 14f, 14g, and 14h, support bearings 13e, 13f, 13g, and 13h, and support rolls 12c and 12d. At the same time, when the delivery-side tapered wedges 18a, 18b, 18c, and 18d are removed, their thickness decreases, causing the side blocks 17a and 17b to move toward the delivery side by that amount, and the support bearings 30a, 30b, 30c, and 30d installed on the operating side and driving side also move toward the delivery side by δ via the arms 32a and 32b and shafts 31a, 31b, 31c, and 31d, supporting the work rolls 2a and 2b.

[0130] In this embodiment, the tapered wedges 18a, 18b, 18c, 18d, 18e, 18f, 18g, and 18h ​​are moved in and out by a motor-driven worm jack.

[0131] Cobble guards 33a, 33b are provided on the exit sides of the central portions of the work rolls 2a, 2b. The cobble guards 33a, 33b may be provided with coolant spray headers (not shown). These coolant spray headers cool the work rolls 2a, 2b. Furthermore, the coolant spray headers may be provided with multiple zones in the strip width direction, and the coolant flow rate may be varied or turned on / off for each zone. This makes it possible to control the strip shape.

[0132] For example, if the strip is locally stretched (not stretched) in the strip width direction, by reducing or turning off the coolant and flow rate in the zone of the coolant spray header at the same position in the strip width direction, the cooling of the work rolls 2a, 2b is suppressed, the thermal expansion of that part increases accordingly, and the diameter becomes larger, and as a result, the strip shape changes from a stretched state only in that part to a flat shape. In this embodiment, since coolant is sprayed on the roll surface after rolling on the delivery side, the cooling and shape control effects are greater than those of providing a coolant spray header on the entry side.

[0133] In the present embodiment, even if the work roll offset amount δ of the work rolls 2a, 2b is zero, the work roll horizontal force Fwh acting on the work rolls 2a, 2b shown in Figure 22 acts only in the entry direction. On the other hand, because the work rolls 2a, 2b are supported on their entry sides by the support rolls 12c, 12d over their entire length in the strip width direction, deflection of the work rolls 2a, 2b is extremely small. Therefore, in the present embodiment, the work roll offset amount δ may be zero.

[0134] In this embodiment, an example has been shown in which support rolls 12c, 12d and support bearings 13e, 13f, 13g, 13h are arranged on the entry side, and are supported over the entire length in the strip width direction, but these may also be installed only on the exit side.

[0135] In this embodiment, the pair of upper and lower work rolls 2a, 2b are supported on the entry side over their entire length in the strip width direction by an example in which the support rolls 12c, 12d, support bearings 13e, 13f, 13g, 13h, shafts 14e, 14f, 14g, 14h, and arms 15c, 15d are attached so as to be swingable around the first intermediate roll bearings 4a, 4b, 4c, 4d via shafts 16c, 16d. However, these support rolls 12c, 12d, support bearings 13e, 13f, 13g, 13h, shafts 14e, 14f, 14g, 14h, and arms 15c, 15d may also be attached so as to be swingable around the side blocks 17c, 17d via shafts 16c, 16d. Alternatively, the support rolls 12c and 12d and the support bearings 13e, 13f, 13g, and 13h may be directly supported by hydraulic cylinders or worm jacks.

[0136] Furthermore, in the example shown, the pair of upper and lower work rolls 2a, 2b are supported on the operation side and drive side at the outlet sides of the work rolls 2a, 2b by the support bearings 30a, 30b, 30c, 30d, shafts 31a, 31b, 31c, 31d, and arms 32a, 32b, 32c, 32d, which are swingably attached to the first intermediate roll bearings 4a, 4b, 4c, 4d via the shafts 16a, 16b, 16c, 16d. However, these support bearings 30a, 30b, 30c, 30d, shafts 31a, 31b, 31c, 31d, and arms 32a, 32b, 32c, 32d may also be swingably attached to the side blocks 17a, 17b via the shafts 16a, 16b, 16c, 16d.

[0137] Also, the support bearings 30a, 30b, 30c, and 30d may be directly supported by hydraulic cylinders or worm jacks.

[0138] The other configurations and operations are substantially the same as those of the rolling mill of the first embodiment described above, and details thereof will be omitted.

[0139] The rolling mill according to the sixth embodiment of the present invention also provides substantially the same effects as those of the rolling mill according to the first embodiment described above.

[0140] <Seventh embodiment> A rolling mill according to a seventh embodiment of the present invention will be described with reference to Figures 18 to 20. Figure 18 is a side view of an eight-high rolling mill according to the seventh embodiment, Figure 19 is a cross-sectional view taken along the line F-F in Figure 18, and Figure 20 is a detailed explanatory view of another eight-high rolling mill according to the seventh embodiment.

[0141] 18 to 20, in a seventh embodiment of the present invention, a pair of upper and lower work rolls 36a, 36b have tapered roll shoulders 36c, 36d at roll barrel end positions that are point symmetrical in the upper and lower axial directions with respect to the strip width center of the strip 1. These roll shoulders 36c, 36d are provided on the opposite side in the strip width direction to the roll shoulders 3c, 3d of the first intermediate rolls 3a, 3b, respectively.

[0142] The upper work roll 36a is supported at its operation side shaft end by a thrust bearing 37a and at its drive side shaft end by a thrust bearing 37c, while the lower work roll 36b is supported at its operation side shaft end by a thrust bearing 37b and at its drive side shaft end by a thrust bearing 37d.

[0143] 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, respectively. The brackets 39a, 39b, 39c, and 39d are attached to hydraulic cylinders 40a, 40b, 40c, and 40d.

[0144] Therefore, the upper work roll 36a is shifted to the drive side in the roll axial direction by the pushing of the hydraulic cylinder 40a and the pulling of the hydraulic cylinder 40c. Also, the upper work roll 36a is shifted to the operation side in the roll axial direction by the pulling of the hydraulic cylinder 40a and the pushing of the hydraulic cylinder 40c.

[0145] The lower work roll 36b is shifted to the roll axial direction operating side by the pull of the hydraulic cylinder 40b and the push of the hydraulic cylinder 40d. The lower work roll 36b is shifted to the roll axial direction driving side by the push of the hydraulic cylinder 40b and the pull of the hydraulic cylinder 40d.

[0146] By shifting the tapered roll shoulders 36c, 36d of the work rolls 36a, 36b, which are symmetrical above and below the strip width center, to the strip ends by hydraulic cylinders 40a, 40b, 40c, 40d, it is possible to reduce the sudden thickness of the strip at the strip ends, known as edge drop. In the present invention, "aligning the positions of the roll shoulders 36c, 36d of the work rolls 36a, 36b with the strip width ends of the strip 1" does not require that the positions of the roll shoulders 36c, 36d of the work rolls 36a, 36b be aligned strictly with the strip width ends of the strip 1, but includes shifting the positions of the roll shoulders 36c, 36d of the work rolls 36a, 36b to align with the strip width ends or their vicinity within a range that allows edge drop to be generated.

[0147] A method for reducing edge drop by shifting the work rolls 36a, 36b having tapered roll shoulders 36c, 36d will be described below.

[0148] First, the work rolls 36a, 36b are provided with tapered roll shoulders 36c, 36d in vertically point-symmetric directions, and the distance between the roll shoulder positions and the strip edge is denoted by δw as shown in FIG.

[0149] As shown in FIG. 20, a thickness gauge 43 is provided at the exit side of the rolling mill to measure the thickness of the plate at one or more points near the plate ends on the operating side and the driving side.

[0150] If the thickness of the strip measured on the operating side at one or more points near the strip edge is thinner than a predetermined thickness, the upper work roll 36a is shifted toward the drive side, which is in the direction of narrowing the roll axis width. That is, the upper work roll 36a is shifted in the direction to increase δw.

[0151] Conversely, if the measured thickness of the strip near the strip edge is greater than the predetermined thickness, the upper work roll 36a is shifted toward the operating side, which is the roll shaft width direction. That is, the upper work roll 36a is shifted in the direction to reduce δw.

[0152] Furthermore, if the plate thickness measured on the drive side at one or more points near the plate end differs from the predetermined plate thickness, the lower work roll 36b is shifted to similarly achieve the predetermined plate thickness.

[0153] The other configurations and operations are substantially the same as those of the rolling mill of the first embodiment described above, and details thereof will be omitted.

[0154] In the rolling mill of the seventh embodiment of the present invention, substantially the same effects as those of the rolling mill of the first embodiment described above can be obtained, and further, even in a small diameter work roll mill equipped with support rolls and support bearings, work roll shifting is possible, making it possible to reduce edge drop.

[0155] Eighth Embodiment A rolling mill according to an eighth embodiment of the present invention will be described with reference to Figures 21 and 22. Figure 21 is a detailed explanatory diagram of an eight-high rolling mill according to this eighth embodiment, and Figure 22 is a plan view of the eight-high rolling mill according to this eighth embodiment.

[0156] As shown in Figure 21, the eight-high rolling mill of the eighth embodiment is an eight-high rolling mill like the third embodiment, except that load cells 44a, 44b, 44c, 44d, 44e, 44f, 44g, and 44h are installed between tapered wedges 19a, 19b, 19c, 19d, 19e, 19f, 19g, and 19h and housings 11a and 11b.

[0157] These load cells 44a, 44b, 44e, and 44f measure the horizontal force Fwh applied to the inlet / outlet side of the upper work roll 2a. Also, load cells 44c, 44d, 44g, and 44h measure the horizontal force Fwh applied to the inlet / outlet side of the lower work roll 2b.

[0158] Here, the work roll offset amount δ is set to a value that makes the horizontal force Fwh applied to the entry and exit sides of the pair of upper and lower work rolls 2a, 2b a constant value close to 0 or an allowable value. This makes it possible to suppress the work roll deflection ξ, thereby reducing defects in the strip shape.

[0159] In the fourth embodiment, the intermediate roll offset amount α is set to a value that makes the horizontal force Fwh applied to the entry and exit sides of the pair of upper and lower work rolls 2a, 2b a constant value close to 0 or an allowable value. Instead of directly measuring the horizontal force Fwh applied to the entry and exit sides of the pair of upper and lower work rolls 2a, 2b, the vertical drive torque of the pair of upper and lower first intermediate rolls 3a, 3b may be measured with a torque meter (not shown), and the horizontal force Fwh applied to the entry and exit sides of the pair of upper and lower work rolls 2a, 2b may be calculated from equations (1), (2), and (3).

[0160] 22, gap sensors 41a, 41b, 41c, and 41d are installed in the center of the roll axis direction on the cobble guards 33a and 33c, and these sensors measure the horizontal gap between the pair of upper and lower work rolls 2a and 2b. This makes it possible to determine the horizontal deflection ξ of the pair of upper and lower work rolls 2a and 2b. Here, the work roll offset amount δ or the intermediate roll offset amount α is set to a value such that the deflection ξ of the pair of upper and lower work rolls 2a and 2b is a constant value close to 0 or within the allowable range. As a result, strip shape defects can be reduced.

[0161] The other configurations and operations are substantially the same as those of the rolling mill of the first embodiment described above, and details thereof will be omitted.

[0162] The rolling mill according to the eighth embodiment of the present invention also provides substantially the same effects as those of the rolling mill according to the first embodiment described above.

[0163] <Ninth embodiment> A tandem rolling mill according to a ninth embodiment of the present invention will be described with reference to Fig. 23. Fig. 23 is an explanatory diagram of the tandem rolling mill according to the ninth embodiment.

[0164] The tandem rolling mill 1000 of this embodiment, in which a plurality of rolling mills are arranged, is equipped with at least one stand of the rolling mill described in any one of the first to eighth embodiments, and Fig. 23 shows an example in which the rolling mills described in the first embodiment are applied to the second stand 200, third stand 300, and fourth stand 400 of the tandem rolling mill 1000 which is equipped with the first stand 100, second stand 200, third stand 300, fourth stand 400, and fifth stand 500. In such a tandem rolling mill 1000, small diameter work rolls can be applied to the second stand 200, third stand 300, and fourth stand 400, making it possible to strongly reduce hard materials.

[0165] The number of stands of the tandem rolling mill is not particularly limited, and may be two or more. In addition, it is sufficient that at least one stand is a rolling mill described in any one of Examples 1 to 8, and all stands may be rolling mills such as those of Example 1.

[0166] The other configurations and operations are substantially the same as those of the rolling mill of the first embodiment described above, and details thereof will be omitted.

[0167] Furthermore, for the rear stands of a tandem mill, high-speed rolling, good sheet shape, and good drainage at the mill delivery side are required, and therefore, the installation of a coolant spray header for cooling the work rolls at the mill entry side of the rolling mill and for controlling the coolant zone for correcting the sheet shape, as well as the installation of a cobble guard at the mill delivery side, as explained in the third embodiment, is extremely effective for this purpose.

[0168] Furthermore, when the work roll shift rolling mill as explained in the seventh embodiment is applied to a tandem mill, the edge drop reduction effect is greatest when it is applied to all stands. In particular, when it is applied only to the first stand 100 or the second stand, the plate thickness in these stands is greater than in the other stands, and the edge drop reduction effect of the work roll shift is correspondingly greater than in the other stands, so the investment effect is great.

[0169] The tandem rolling mill 1000 of the ninth embodiment of the present invention is equipped with at least one stand of the rolling mill described in the first to eighth embodiments, and therefore has substantially the same effects as the rolling mills of the first embodiment and the like described above.

[0170] <Others> The present invention is not limited to the above-described examples, and includes various modifications. The above-described examples have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those having all of the described configurations.

[0171] It is also possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of one embodiment to the configuration of another embodiment.It is also possible to add, delete, or replace part of the configuration of each embodiment with the configuration of another embodiment.

[0172] 1; Strip 2a, 2b; Work rolls 3a, 3b; First intermediate rolls 3c, 3d; Roll shoulders (first intermediate roll shoulders) 4a, 4b, 4c, 4d; First intermediate roll bearings 4e, 4f; First intermediate roll bearing housings 5a, 5b; Second intermediate rolls 5c, 5d; Roll shoulders (second intermediate roll shoulders) 6a, 6b, 6c, 6d; Second intermediate roll bearings 6e, 6f; Second intermediate roll bearing housings 7a, 7b; Backup rolls 8a, 8b, 8c, 8d; Backup roll bearing housings 9a, 9b; Pass line adjustment devices 10a, 10b; Press-down hydraulic cylinders 11a, 11b; Housings 12a, 12b, 12c, 12d; Support rolls 13a, 13b, 13c, 13d, 13e, 13f, 13g, 13h; support bearings 14a, 14b, 14c, 14d, 14e, 14f, 14g, 14h; shafts 15a, 15b, 15c, 15d; arms 16a, 16b, 16c, 16d; shafts 17a, 17b, 17c, 17d; side blocks (beams) 18a, 18b, 18c, 18d, 18e, 18f, 18g, 18h; tapered wedges 19a, 19b, 19c, 19d, 19e, 19f, 19g, 19h; tapered wedges 20a, 20b, 20c, 20d, 20e, 20f, 20g, 20h; hydraulic cylinders Reference Signs List 21a, 21b... Thrust bearings 22a, 22b... Shafts 23a, 23b, 23c, 23d, 24a, 24b, 24c, 24d... Bending cylinders 25a, 25b: Work rolls (work rolls for a six-high rolling mill) 26a, 26b, 26c, 26d... Work roll bearings 27a, 27b: Intermediate rolls (intermediate rolls for a six-high rolling mill) 27c, 27d... Roll shoulders 28a, 28b, 28c, 28d... Intermediate roll bearings 28e, 28f... Intermediate roll bearing housings 29a, 29b, 29c, 29d... Bending cylinders 30a, 30b, 30c, 30d, 30e, 30f, 30g, 30h... Support bearings 31a, 31b, 31c, 31d, 31e, 31f, 31g, 31h... Shafts 32a, 32b, 32c, 32d, 32e, 32f, 32g, 32h... Arms 33a, 33b, 33c, 33d; Cobble guards 34a, 34b, 34c, 34d... Hydraulic cylinders 35a, 35b; Coolant spray headers 36a, 36b; Work rolls 36c, 36d;Roll shoulders (work roll shoulders) 37a, 37b, 37c, 37d... thrust bearings 38a, 38b, 38c, 38d... shafts 39a, 39b, 39c, 39d... brackets 40a, 40b, 40c, 40d; hydraulic cylinders (work roll shifting devices) 41a, 41b, 41c, 41d... gap sensors 42a, 42b, 42c, 42d, 42e, 42f, 42g, 42h... hydraulic cylinders 43... plate thickness gauges 44a, 44b, 44c, 44d, 44e, 44f, 44g, 44h; load cells (detectors) 50a, 50b; shift cylinders (first intermediate roll shifting devices) 51a, 51b; shift cylinders (second intermediate roll shifting devices) 52a, 52b; shift cylinders 60... control device 100...first stand 200...second stand 300...third stand 400...fourth stand 500...fifth stand 1000...tandem rolling mill;

Claims

1. An eight-high rolling mill comprising: a pair of work rolls for rolling strip; a pair of first intermediate rolls having first intermediate roll shoulders tapered at positions symmetrical about a point in the vertical axial direction and supporting the work rolls; a pair of second intermediate rolls having second intermediate roll shoulders tapered at positions symmetrical about a point in the vertical axial direction opposite to that of the first intermediate rolls and supporting the first intermediate rolls; a pair of backup rolls supporting the second intermediate rolls; a group of support rolls or support bearings provided on the entry and / or exit sides of the work rolls; a first intermediate roll shifting device for shifting the position of the first intermediate roll shoulders in the axial direction to align with the widthwise ends of the strip; and a second intermediate roll shifting device for shifting the position of the second intermediate roll shoulders in the axial direction to align with the widthwise ends of the strip.

2. An eight-high rolling mill according to claim 1, wherein the work rolls, the first intermediate rolls, and the second intermediate rolls are switchable with a pair of six-high rolling mill work rolls for rolling the strip and a pair of six-high rolling mill intermediate rolls for supporting the six-high rolling mill work rolls.

3. An eight-high rolling mill according to claim 2, wherein the sum of the maximum diameter of the work rolls, the maximum diameter of the first intermediate roll, and the maximum diameter of the second intermediate roll is the same as the sum of the maximum diameter of the work rolls for the six-high rolling mill and the maximum diameter of the intermediate rolls for the six-high rolling mill, or is within an error range of ±10%.

4. An eight-high rolling mill according to claim 2, wherein the sum of the minimum diameter of the work roll, the minimum diameter of the first intermediate roll, and the minimum diameter of the second intermediate roll is the same as the sum of the minimum diameter of the work roll for the six-high rolling mill and the minimum diameter of the intermediate roll for the six-high rolling mill, or is within an error range of ±10%.

5. An eight-high rolling mill according to any one of claims 1 to 4, wherein a pair of said work rolls are supported by said support roll group over the entire length in the strip width direction on both the entry side and the exit side of said strip.

6. An eight-high rolling mill as claimed in claim 5, wherein the pair of work rolls are supported by the support roll group at the entire length in the plate width direction on the entry side and exit side, the support roll group is rotatably installed on an arm swingably connected to the chock of the first intermediate roll, and the position of the arm in the pass direction is supported by a beam whose position in the pass direction is adjustable.

7. An eight-high rolling mill according to any one of claims 1 to 4, further comprising a coolant spray header and / or a cobble guard arranged at the centre of the strip in the width direction, wherein the support roll group or the support bearing supports the work roll on the operation side and drive side of the work roll, and the offset amount of the work roll in the pass direction is changed by moving the support roll group or the support bearing in and out on the entry side or exit side in the pass direction, or the offset amount of the first intermediate roll in the pass direction is changed by moving the bearing of the first intermediate roll in and out on the entry side or exit side in the pass direction.

8. An eight-high rolling mill as claimed in claim 7, wherein the support roll group or the support bearings that support the work rolls on the operating side and drive side are rotatably installed on arms that are swingably connected to first intermediate roll chocks that hold the support roll group or the support bearings, and the pass direction position of the arms is adjusted by a beam that is position adjustable in the pass direction, thereby changing the offset amount of the work rolls in the pass direction.

9. An eight-high rolling mill as claimed in claim 7, wherein a first cluster arm comprising the support roll group or the support bearings that support the work rolls on the operating side and driving side, first intermediate roll chocks that hold the support roll group or the support bearings, and an arm swingably connected to the first intermediate roll chock, and a second cluster arm comprising a second support roll group that supports the work rolls over the entire length in the plate width direction on the entry side and exit side of the work rolls, a second first intermediate roll chock that holds the second support roll group, and an arm swingably connected to the second first intermediate roll chock, are selectively interchangeable.

10. An eight-high rolling mill as claimed in claim 7, comprising: a third cluster arm, at the entry or exit side of the work rolls, comprising the support roll group or the support bearings supporting the work rolls on the operating and driving sides, a first intermediate roll chock holding the support roll group or the support bearings, and an arm swingably connected to the first intermediate roll chock; and a fourth cluster arm, at the entry or exit side of the work rolls, comprising a second support roll group supporting the work rolls over the entire length of the work rolls in the plate width direction, a second first intermediate roll chock holding the second support roll group, and an arm swingably connected to the second first intermediate roll chock.

11. An eight-high rolling mill according to any one of claims 1 to 4, wherein the work rolls have tapered work roll shoulders at positions point-symmetrical with respect to the top and bottom axial directions opposite to those of the first intermediate rolls, and further comprising a work roll shifting device that shifts the positions of the work roll shoulders in the axial direction to align with the widthwise ends of the strip.

12. An eight-high rolling mill according to any one of claims 1 to 4, further comprising a detector for detecting the amount of deflection or horizontal force of the work rolls, and changing the amount of offset of the work rolls or the first intermediate roll in the pass direction based on the detection results of the detector.

13. A tandem rolling mill comprising a plurality of rolling mills arranged side by side, the tandem rolling mill comprising at least one stand of the eight-high rolling mill according to any one of claims 1 to 3.

14. A method for modifying a rolling mill, which mutually replaces a pair of work rolls for rolling strip, a pair of first intermediate rolls having first intermediate roll shoulders tapered at positions symmetrical about a point in the vertical axial direction and supporting the work rolls, a pair of second intermediate rolls having second intermediate roll shoulders tapered at positions symmetrical about a point in the vertical axial direction opposite to those of the first intermediate rolls and supporting the first intermediate rolls, a pair of six-high rolling mill work rolls for rolling the strip, and a pair of six-high rolling mill intermediate rolls supporting the six-high rolling mill work rolls.

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