Multi-stage rolling mill, maintenance and inspection method for multi-stage rolling mill, and method for using multi-stage rolling mill

Abstract

To provide a multistage rolling mill, a maintenance and inspection method for a multistage rolling mill, and a using method for a multistage rolling mill capable of forming a space between top and bottom roll groups in a shorter time than before.SOLUTION: A multistage rolling mill comprises: a top inner housing 30 and a bottom inner housing 32 that support a plurality of pairs of backing assemblies 20; an outer housing 40 that supports the top inner housing 30 and the bottom inner housing 32 from an entry side and an exit side in a rolling direction of a metal strip 5; and an entry side coolant spray header 50a and an exit side coolant spray header 50b configured so as to inject coolant to the metal strip 5 at a portion bitten by a pair of work rolls 10. The entry side coolant spray header 50a and the exit side coolant spray header 50b are configured so as to be movable in the rolling direction and / or an opposite direction to the rolling direction of the metal strip 5.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a multi-stage rolling mill, a maintenance and inspection method for a multi-stage rolling mill, and a method of using a multi-stage rolling mill. [Background technology]

[0002] Patent document 1 describes a set of stacked rolls with parallel longitudinal axes arranged in at least one single plane that is approximately perpendicular to the direction of strip movement, and that the longitudinal axis of one of the rolls is defined as the instantaneous axis of rotation, which is parallel to the line formed by the roll and passes through the center of mass of the roll. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2015-520031 Summary of the Invention [Problem to be solved by the invention]

[0004] Cluster-type rolling mills (hereinafter sometimes referred to as "multi-stage rolling mills") are sometimes used as rolling mills for electrical steel sheets.

[0005] In such cluster-type rolling mills, coolant is sprayed onto the bite portion of the work roll to appropriately control the plate thickness, so the coolant nozzle must be located close to the work roll.

[0006] The rolls need to be replaced and inspected periodically, but in cluster-type rolling mills the space between the upper and lower roll groups is narrow, making it difficult to access and conduct maintenance inspections.

[0007] Therefore, for example, Patent Document 1 describes a method in which a table, to which a spray device for lubricating and cooling the strip and rolls is fixed, can be easily inserted and removed into and from the rolling stand by sliding it in the longitudinal direction of the row of bearing rolls.

[0008] However, in the above-mentioned conventional technology, the sliding direction of the table is the longitudinal direction of the rolls, and therefore the sliding stroke is long, so there is an issue that it takes time to retract the table and form a space between the upper and lower roll groups.

[0009] The present invention provides a multi-stage rolling mill capable of forming a space between upper and lower roll groups in a shorter time than conventional methods, a maintenance and inspection method for the multi-stage rolling mill, and a method of using the multi-stage rolling mill. [Means for solving the problem]

[0010] The present invention includes a plurality of means for solving the above-mentioned problems. One example of the means includes a pair of work rolls for rolling a metal strip, a plurality of pairs of intermediate rolls supporting the pair of work rolls, a plurality of pairs of backing assemblies supporting the plurality of pairs of intermediate rolls, an inner housing supporting the plurality of pairs of backing assemblies, an outer housing supporting the inner housing from the entry side and the exit side in the rolling direction of the metal strip, and a coolant spray header configured to spray coolant onto the metal strip at the biting portion of the pair of work rolls, the coolant spray header being configured to be movable in the rolling direction and / or the counter-rolling direction of the metal strip. The coolant spray header has a connection portion where an upper coolant spray header provided on the upper side of the metal strip and a lower coolant spray header provided on the lower side of the metal strip are connected on the outer side in the width direction of the metal strip, and the connection portion is supported by a member on the outer side of the inner housing in the rolling direction. . Effect of the Invention

[0011] According to the present invention, it is possible to form a space between the upper and lower roll groups in a shorter time than in the past. Problems, configurations and effects other than those described above will become apparent from the following description of the embodiments. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a front view of a multi-stage rolling mill according to the embodiment. [Diagram 2] FIG. 2 is a front view showing a state in which a coolant spray header is retracted in a direction opposite to the rolling direction in the multi-stage rolling mill of the embodiment. [Diagram 3] FIG. 2 is a front view showing a state in which the space between the upper inner housing and the lower inner housing is opened and the upper work roll is removed in the multi-stage rolling mill of the embodiment. [Figure 4] FIG. 2 is a front view showing a state in which the lower work roll and the lower first intermediate roll are removed and the upper first intermediate roll is supported by a support base in the multi-stage rolling mill of the embodiment. [Diagram 5] FIG. 2 is a front view showing a state in which an upper first intermediate roll has been removed in the multi-stage rolling mill of the embodiment. [Figure 6] FIG. 2 is a front view showing a state in which a second lower intermediate roll has been removed in the multi-stage rolling mill of the embodiment. [Figure 7] FIG. 2 is a front view showing a state in which an upper second intermediate roll and a lower backing assembly are removed in the multi-stage rolling mill of the embodiment. [Figure 8] FIG. 4 is a front view showing another embodiment of a multi-stage rolling mill according to the present invention. [Figure 9] FIG. 11 is a front view showing a state in which a lower inner housing is removed from the rolling mill in another embodiment of the multi-stage rolling mill according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] BEST MODE FOR CARRYING OUT THE DISCLOSURE A multi-stage rolling mill, a maintenance and inspection method for the multi-stage rolling mill, and a method for using the multi-stage rolling mill according to the present invention will be described with reference to Figs.

[0014] FIG. 1 is a front view of a multi-stage rolling mill according to an embodiment. FIG. 2 is a front view showing a state in which a coolant spray header is retracted in the direction opposite to the rolling direction. FIG. 3 is a front view showing a state in which the space between the upper inner housing and the lower inner housing is opened and the upper work roll is removed. FIG. 4 is a front view showing a state in which the lower work roll and the lower first intermediate roll are removed and the upper first intermediate roll is supported by a support stand. FIG. 5 is a front view showing a state in which the upper first intermediate roll is removed. FIG. 6 is a front view showing a state in which the lower second intermediate roll is removed. FIG. 7 is a front view showing a state in which the upper second intermediate roll and the lower backing assembly are removed. FIG. 8 is a front view showing another embodiment of a multi-stage rolling mill. FIG. 9 is a front view showing a state in which the lower inner housing is taken out of the rolling mill.

[0015] In the drawings used in this specification, the same or corresponding components are denoted by the same or similar reference numerals, and repeated description of these components may be omitted.

[0016] In the following embodiment, an example of a 20-stage cluster-type multi-stage rolling mill consisting of an inner housing and an outer housing, with upper and lower divided inner housings that can be opened and closed vertically, is shown and described; however, the multi-stage rolling mill is not limited to this structure, and the structure of this embodiment can be applied to various multi-stage rolling mills.

[0017] First, the overall configuration of the multi-stage rolling mill of this embodiment will be described with reference to FIG.

[0018] The multi-high rolling mill 1 of this embodiment shown in FIG. 1 is a cluster-type 20-high rolling mill for rolling a metal strip 5, and is particularly suitable for rolling hard materials such as stainless steel sheets, electromagnetic steel sheets, and copper alloys.

[0019] In FIG. 1, the multi-stage rolling mill 1 is equipped with a pair of upper and lower work rolls 10, two upper and lower pairs of first intermediate rolls 12, three upper and lower pairs of second intermediate rolls 14, and four upper and lower pairs of upper backing assemblies (A-shaft, B-shaft, C-shaft, D-shaft) and lower backing assemblies (E-shaft, F-shaft, G-shaft, H-shaft) (hereinafter collectively referred to as backing assemblies 20) consisting of split backing bearings, shafts, and saddles (all of which are omitted for convenience of illustration).

[0020] The pair of work rolls 10 are in direct contact with the metal strip 5 and roll the metal strip 5 .

[0021] Each pair of upper and lower work rolls 10 is supported in contact with two upper and lower pairs of first intermediate rolls 12. Furthermore, each of these two upper and lower pairs of first intermediate rolls 12 is supported in contact with three upper and lower pairs of second intermediate rolls 14.

[0022] The three pairs of second intermediate rolls 14, one above the other, are supported in contact with backing assemblies 20 (Axis A, B, C, D) on the vertically upper side of the metal strip 5, and backing assemblies 20 (Axis E, F, G, H) on the vertically lower side of the metal strip 5.

[0023] The multi-stage rolling mill 1 also includes an upper inner housing 30 that supports an upper backing assembly 20 (axis A, axis B, axis C, axis D) above the metal strip 5 in the vertical direction, and a lower inner housing 32 that supports a lower backing assembly 20 (axis E, axis F, axis G, axis H) below the metal strip 5 in the vertical direction.

[0024] The upper inner housing 30 and the lower inner housing 32 are supported by an outer housing 40 from the entry side and the exit side in the rolling direction of the metal strip 5 .

[0025] The push-up cylinder 60 is provided vertically below the lower inner housing 32 so as to support the lower inner housing 32, and is driven when a gap is formed between the upper and lower rolls.

[0026] In addition, for roll cooling and rolling lubrication, an entry-side coolant spray header 50a is provided which sprays coolant from above and below on the entry side in the rolling direction of the metal strip 5 onto the bite portions of the metal strip 5 between the pair of upper and lower work rolls 10, and an exit-side coolant spray header 50b is provided which sprays coolant from above and below on the exit side in the rolling direction of the metal strip 5.

[0027] The inlet coolant spray header 50a is formed by connecting an upper inlet coolant spray header 52a located on the vertically upper side of the metal strip 5 and a lower inlet coolant spray header 54a located on the vertically lower side by an inlet connecting member 56a in the outer housing part on the drive side and / or operation side on the outer side of the width of the metal strip 5, thereby forming an integrated header.

[0028] This inlet coolant spray header 50a has a shape extending from the work roll 10 side to the outer housing 40 side when viewed from the front side of the multi-stage rolling mill 1, and is supported by outer members in the counter-rolling direction from the upper inner housing 30 and the lower inner housing 32.

[0029] In particular, in this embodiment, the inlet connection member 56a of the inlet coolant spray header 50a is provided between the upper inner housing 30 and the lower inner housing 32. anti It is supported by the outer housing 40 as an outer member in the rolling direction. Note that the present invention is not limited to being supported by the outer housing 40, and the inlet coolant spray header may be structured so as to pass through the outer housing 40 without contacting it, and further support the inlet coolant spray header with an outer mill guide.

[0030] Like the inlet coolant spray header 50a, the outlet coolant spray header 50b has an outlet upper coolant spray header 52b located vertically above the metal strip 5 and an outlet lower coolant spray header 54b located vertically below the metal strip 5, which are connected and integrated by an outlet connecting member 56b in the outer housing part on the drive side and / or operation side on the outer side of the width of the metal strip 5.

[0031] This outlet coolant spray header 50b has a shape extending from the work roll 10 side to the outer housing 40 side when viewed from the front side of the multi-stage rolling mill 1, and is supported by members outer than the upper inner housing 30 and the lower inner housing 32 in the rolling direction.

[0032] In particular, in this embodiment, the outlet connection member 56b of the outlet coolant spray header 50b is supported by the outer housing 40 as a member that is outer in the rolling direction than the upper inner housing 30 and the lower inner housing 32. Note that the embodiment is not limited to being supported by the outer housing 40, and the outlet coolant spray header may be structured so as to pass through the outer housing 40 without contacting it, and further support the outlet coolant spray header with an outer mill guide.

[0033] In this embodiment, the entry coolant spray header 50a is further provided with a movement mechanism 45a that enables the entry coolant spray header 50a to move in the anti-rolling direction of the metal strip 5, more specifically, as shown in FIG. 2, from the front side of the multi-stage rolling mill 1, so that the tip of the entry coolant spray header 50a on the work roll 10 side is moved to the outside of the rolling direction further than the axis of the backing assembly 20 (axis D, axis E, center of the backing assembly 20) that is the furthest from the work roll 10 in the rolling direction. The exit coolant spray header 50b is further provided with a movement mechanism 45b that enables the exit coolant spray header 50b to move in the rolling direction of the metal strip 5, more specifically, as shown in FIG. 2, from the front side of the multi-stage rolling mill 1, so that the tip of the exit coolant spray header 50b on the work roll 10 side is moved to the outside of the rolling direction further than the axis of the backing assembly 20 (axis A, axis H, center of the backing assembly 20) that is the furthest from the work roll 10 in the rolling direction.

[0034] The configuration of the moving mechanisms 45a, 45b that enable the entry coolant spray header 50a to move so that its tip on the work roll 10 side is to the outside of the entry side in the rolling direction, further than the axis of the backing assembly 20 that is the farthest from the work roll 10 in the rolling direction, and the exit coolant spray header 50b to move so that its tip on the work roll 10 side is to the outside of the exit side in the rolling direction, further than the axis of the backing assembly 20 that is the farthest from the work roll 10 in the rolling direction, is not particularly limited, and various configurations can be adopted, such as, for example, a hydraulic cylinder whose cylinder extends in the rolling direction or counter-rolling direction, or a ball screw, rack, pinion, etc. that convert rotational motion into linear motion, and are not particularly limited.

[0035] For example, during maintenance and inspection of the multi-stage rolling mill 1, the movement mechanisms 45a, 45b move the inlet coolant spray header 50a in the direction opposite to the rolling direction of the metal strip 5, and move the outlet coolant spray header 50b in the rolling direction of the metal strip 5. As a result, the tip of the inlet coolant spray header 50a opens outward relative to the D-axis and the E-axis, and the tip of the outlet coolant spray header 50b opens outward relative to the A-axis and the H-axis, so that, as shown in Fig. 3, the gap between the upper inner housing 30 and the lower inner housing 32 can be opened to obtain space within the multi-stage rolling mill 1, and various roll changing tools can be proposed, enabling changeover to be performed in a short time.

[0036] As a result, it is easy to remove the upper work roll 10 by pulling it out in the width direction of the metal strip 5, as shown in FIG. 3, to remove the lower work roll 10, as shown in FIG. 4, and further, when removing the lower first intermediate roll 12, as shown in FIG. 4, to support and stabilize the upper first intermediate roll 12 with a support base 70, to remove the upper first intermediate roll 12, as shown in FIG. 5, to remove the lower second intermediate roll 14, as shown in FIG. 6, to remove the upper second intermediate roll 14 and the lower backing assembly 20, as shown in FIG. 7, and further, to pull out and remove the upper backing assembly 20, so that replacement work can be performed more easily than in the past.

[0037] Conventionally, even when an automatic changing device was used for changing rolls, the device was large-scale, so that it was common to remove each roll from the multi-high rolling mill 1 one by one, which required time for changing rolls, but the configuration of this embodiment makes it possible to adopt various changing methods, such as changing multiple rolls at the same time, stably. In particular, it becomes possible to stably and efficiently change the second intermediate roll 14 and the backing assembly 20, which are performed by unstable Porter bar operation.

[0038] When only the work rolls 10 are to be replaced, the work rolls 10 can be pulled out in the axial direction with the metal strip 5 still threaded between the upper and lower work rolls 10. In contrast, when the first intermediate roll 12, the second intermediate roll 14, or the backing assembly 20 are to be replaced, the metal strip 5 is first pulled out, and then the entry coolant spray header 50a and the exit coolant spray header 50b are retracted and the work rolls 10 are removed.

[0039] Furthermore, the timing for moving the entry side coolant spray header 50a and the exit side coolant spray header 50b in the rolling direction or the anti-rolling direction is not limited to the time of maintenance and inspection.

[0040] For example, during rolling of a metal strip 5, when the leading end of the metal strip 5 is passed between a pair of work rolls 10, the inlet coolant spray header 50a and the outlet coolant spray header 50b can be moved in the rolling direction and / or the counter-rolling direction of the metal strip 5, so as to be closer to the pair of work rolls 10 than during normal rolling.

[0041] During normal rolling of the metal strip 5, the entry coolant spray header 50a and the exit coolant spray header 50b can be moved away from the pair of work rolls 10 when the leading end is threaded.

[0042] Next, another embodiment of the multi-stage rolling mill will be described with reference to FIGS.

[0043] In the multi-stage rolling mill 1A shown in Figures 8 and 9, the lower inner housing 32A is provided with wheels 80 for the lower monoblock housing at its lower part for moving the lower inner housing 32A in the width direction of the metal strip 5, making it possible to move the lower inner housing 32A in the width direction of the metal strip 5 on the installation floor 85.

[0044] This makes it possible to simultaneously pull out the lower roll group (lower work roll 10, lower first intermediate roll 12, lower second intermediate roll 14, lower backing assembly 20 (E-axis, F-axis, G-axis, H-axis)) from the multi-stage rolling mill 1A, making it possible to attach and detach the rolls by operating a crane. This makes it easier to rearrange the rolls, especially the backing assembly 20, and makes it possible to reduce the changeover time to less than half of the conventional time.

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

[0046] The multi-stage rolling mill 1, 1A of the present embodiment described above includes a pair of work rolls 10 for rolling a metal strip 5, multiple pairs of first intermediate rolls 12 and second intermediate rolls 14 supporting the pair of work rolls 10, multiple pairs of backing assemblies 20 supporting the multiple pairs of first intermediate rolls 12 and second intermediate rolls 14, an upper inner housing 30 and a lower inner housing 32 supporting the multiple pairs of backing assemblies 20, an outer housing 40 supporting the upper inner housing 30 and the lower inner housing 32 from the entry side and the exit side in the rolling direction of the metal strip 5, and an entry side coolant spray header 50a and an exit side coolant spray header 50b configured to spray coolant onto the metal strip 5 at the biting portion of the pair of work rolls 10, and the entry side coolant spray header 50a and the exit side coolant spray header 50b are configured to be movable in the rolling direction and / or the counter-rolling direction of the metal strip 5.

[0047] In a multi-stage rolling mill, if the tip of the coolant spray header is not aimed at the gap between the work roll and the metal strip 5, the plate thickness will be disturbed, which will be a disturbance to the control.

[0048] In addition, in a reversible rolling mill for rolling electrical steel sheets, which is an example of the metal strip 5, the amount of coolant sprayed is controlled according to the pass and the sheet speed. However, if the nozzle tip does not approach close to the gap between the work roll and the metal strip 5, the tip of the coolant spray header will not reach the gap between the work roll and the metal strip 5.

[0049] For this reason, it is essential to bring the nozzle close to the gap between the work roll and the metal strip 5. However, this places a space restriction on the operation of replacing the second intermediate roll and the backing assembly of the multi-stage rolling mill, making it difficult to perform a smooth replacement.

[0050] In contrast, in this embodiment, the inlet coolant spray header 50a and the outlet coolant spray header 50b can move in the rolling direction and the anti-rolling direction, so that a space between the roll groups can be formed by moving only a short distance, and the time required to form the space can be shortened compared to the conventional method. Also, since the headers can move in the rolling direction and / or anti-rolling direction of the metal strip 5, vertical movement is substantially unnecessary, and the nozzle tip can be easily moved to the vicinity of the gap between the work roll 10 and the metal strip 5, so that the load of adjustment for cooling can be significantly reduced compared to the conventional method.

[0051] In addition, the entry coolant spray header 50a and the exit coolant spray header 50b have a shape that extends from the work roll 10 side to the outer housing 40 side when viewed from the front side of the multi-stage rolling mill 1, and are supported by members that are outer in the rolling direction than the upper inner housing 30 and the lower inner housing 32. Therefore, even if the header has a shape that is elongated in the rolling direction, the header can be easily moved in the rolling direction or counter-rolling direction, and it is possible to more easily respond to changes in rolling conditions, etc.

[0052] Furthermore, since the inlet coolant spray header 50a and the outlet coolant spray header 50b are supported by the outer housing 40, the position of the spray headers can be fixed relative to the pass line, eliminating the need for equipment and the effort required to adjust the nozzle angle at the header tip. This reduces the amount of work required during maintenance and inspection, and further improves work efficiency.

[0053] In particular, in the case of multi-stage rolling mills, the coolant spray headers were conventionally attached to the upper inner housing and the lower inner housing, respectively, and so it was necessary to adjust the nozzle spray angle depending on the combination of the diameters of the work roll 10, the first intermediate roll 12, and the second intermediate roll 14, and the installation of an angle adjustment device was essential. However, since such a device is no longer necessary, various advantages are obtained, such as space saving and cost reduction.

[0054] In addition, the inlet-side coolant spray header 50a and the outlet-side coolant spray header 50b have an inlet-side upper coolant spray header 52a and an outlet-side upper coolant spray header 52b provided on the upper side of the metal strip 5, and an inlet-side lower coolant spray header 54a and an outlet-side lower coolant spray header 54b provided on the lower side of the metal strip 5, and have an inlet-side connecting member 56a and an outlet-side connecting member 56b connected to the outer side of the width direction of the metal strip 5, and the inlet-side connecting member 56a and the outlet-side connecting member 56b are supported by members outer in the rolling direction than the upper inner housing 30 and the lower inner housing 32. As a result, the upper and lower headers of the metal strip 5 can be integrated, and the upper and lower headers can be moved at the same time, resulting in effects such as simplifying the configuration of the moving mechanisms 45a, 45b and improving the movement efficiency.

[0055] Furthermore, the entry coolant spray header 50a and the exit coolant spray header 50b are configured so that, when viewed from the front side of the multi-stage rolling mill 1, their tips on the work roll 10 side can be moved further outward in the rolling direction than the axis of the backing assembly 20, which is the farthest from the work roll 10 in the rolling direction. This makes it possible to form sufficient space for maintenance, etc., and since the distance the headers can be moved can be made shorter than when the headers are moved in the longitudinal direction of the rolls, the time required to form the space can be shortened.

[0056] The apparatus further includes a support carriage that moves in the width direction of the metal strip 5 and holds from below the upper backing assembly 20 of the multiple pairs of backing assemblies 20 that is provided on the upper side of the metal strip 5, when the entry coolant spray header 50a and the exit coolant spray header 50b are disposed at retracted positions moved in the rolling direction, and the pair of work rolls 10, the multiple pairs of first intermediate rolls 12 and second intermediate rolls 14, and the lower backing assembly 20 of the multiple pairs of backing assemblies 20 that is provided on the lower side of the metal strip 5 are pulled out to the outside of the lower inner housing 32. Conventionally, the upper first intermediate roll 12 and the upper second intermediate roll 14 were lifted from above to prevent them from falling during roll replacement, but the support carriage eliminates the need for a device for lifting the upper roll during roll replacement. In addition, it is now possible to pull the rolls out of the multi-stage rolling mill 1 with the bearing boxes of the second intermediate roll 14, which were removed in order to install the Porter bar device, still attached, eliminating the need to manually remove and attach the bearing boxes in front of the multi-stage rolling mill 1, and in the case of an automatic changer, there is no need for the device itself.

[0057] Furthermore, the inner housing comprises an upper inner housing 30 provided above the metal strip 5 and a lower inner housing 32A provided below the metal strip 5, and the lower inner housing 32A is provided with wheels 80 for the lower monoblock housing at its lower part for moving the lower inner housing 32A in the width direction of the metal strip 5. This makes it possible to simultaneously pull out the lower group of rolls from the rolling mill, greatly improving the efficiency of the replacement work for the lower group of rolls.

[0058] In addition, according to the method of using the multi-stage rolling mill 1 of the present invention, when the leading end of the metal strip 5 is passed between a pair of work rolls 10, the inlet coolant spray header 50a and the outlet coolant spray header 50b are moved in the rolling direction and / or counter-rolling direction of the metal strip 5 to approach the pair of work rolls 10, so that coolant can be effectively supplied at the time of biting when a large load is applied to the work rolls 10, thereby reducing the load.

[0059] Furthermore, during normal rolling of the metal strip 5, by moving the inlet coolant spray header 50a and the outlet coolant spray header 50b away from the pair of work rolls 10 compared to when their leading ends are threaded, it is possible to prevent the leading ends of the inlet coolant spray header 50a and the outlet coolant spray header 50b from coming too close to the work rolls 10 more than necessary.

[0060] <Other> The present invention is not limited to the above-mentioned embodiment, and various modifications and applications are possible. The above-mentioned embodiment has been described in detail to explain the present invention in an easily understandable manner, and the present invention is not necessarily limited to having all of the described configurations. [Explanation of symbols]

[0061] 1,1A...Multi-stage rolling mill 5…Metal strip 10...Work roll 12…First intermediate roll 14…Second intermediate roll 20...Backing assembly 30…Upper inner housing 32, 32A…Lower inner housing 40...Outer housing (outer member in the rolling direction) 45a, 45b…Movement mechanism 50a…Inlet coolant spray header 50b…Outlet coolant spray header 52a…Inlet side upper coolant spray header (Upper coolant spray header) 52b…Outlet side upper coolant spray header (Upper coolant spray header) 54a…Inlet side lower coolant spray header (lower coolant spray header) 54b…Outlet side lower coolant spray header (lower coolant spray header) 56a...inlet connection member (connection portion) 56b...Outlet connection member (connection portion) 60…Push-up cylinder 70...Support stand 80...Wheels for lower monoblock housing (insertion / removal part) 85…Installation floor

Claims

1. A pair of work rolls for rolling a metal strip; A plurality of pairs of intermediate rolls supporting the pair of work rolls; a plurality of pairs of backing assemblies supporting the plurality of pairs of intermediate rolls; an inner housing supporting the pairs of backing assemblies; an outer housing supporting the inner housing from an inlet side and an outlet side in the rolling direction of the metal strip; a coolant spray header configured to spray coolant onto the metal strip at the biting portion between the pair of work rolls; the coolant spray header is configured to be movable in a rolling direction and / or a counter-rolling direction of the metal strip; the coolant spray header has a connection portion at which an upper coolant spray header provided on the upper side of the metal strip and a lower coolant spray header provided on the lower side of the metal strip are connected on the outer side in the width direction of the metal strip, The connection portion is supported by a member that is on the outer side of the inner housing in the rolling direction. Multi-stage rolling mill.

2. In the multi-stage rolling mill according to claim 1, The coolant spray header has a shape extending from the work roll side to the outer housing side when viewed from the front side of the multi-stage rolling mill, and is supported by a member on the outer side of the inner housing in the rolling direction. Multi-stage rolling mill.

3. In the multi-stage rolling mill according to claim 2, The coolant spray header is supported by the outer housing. Multi-stage rolling mill.

4. In the multi-stage rolling mill according to any one of claims 1 to 3, The coolant spray header is configured so that, when viewed from the front side of the multi-stage rolling mill, the tip of the work roll side can be moved to the outside in the rolling direction beyond the axis of the backing assembly that is the furthest from the work roll in the rolling direction. Multi-stage rolling mill.

5. In the multi-stage rolling mill according to any one of claims 1 to 3, The coolant spray header is disposed at a retreated position moved in the rolling direction, and further includes a carriage that moves in the width direction of the metal strip and holds, from below, an upper backing assembly provided on the upper side of the metal strip among the multiple pairs of backing assemblies when the pair of work rolls, the multiple pairs of intermediate rolls, and a lower backing assembly provided on the lower side of the metal strip among the multiple pairs of backing assemblies are in a state of being pulled out to the outside of the inner housing. Multi-stage rolling mill.

6. In the multi-stage rolling mill according to any one of claims 1 to 3, the inner housing includes an upper inner housing provided above the metal strip and a lower inner housing provided below the metal strip, The lower inner housing has an insertion / removal portion at a lower portion for moving the lower inner housing in the width direction of the metal strip. Multi-stage rolling mill.

7. The method for maintaining and inspecting a multi-stage rolling mill according to claim 1, withdrawing the pair of work rolls in a width direction of the metal strip; a step of drawing out the pairs of intermediate rolls in a width direction of the metal strip; and moving the coolant spray header in the rolling direction and / or the anti-rolling direction. Maintenance and inspection methods for multi-stage rolling mills.

8. The method for maintaining and inspecting a multi-stage rolling mill according to claim 7, a step of disposing the coolant spray header at a retreat position moved in the rolling direction and / or the counter-rolling direction, and drawing out the pair of work rolls, the multiple pairs of intermediate rolls, and a lower backing assembly provided below the metal strip among the multiple pairs of backing assemblies, to the outside of the inner housing; and moving a carriage that holds an upper backing assembly provided on the upper side of the metal strip from below, among the plurality of pairs of backing assemblies, in the width direction of the metal strip, to hold the upper backing assembly from below. Maintenance and inspection methods for multi-stage rolling mills.

9. The method for maintaining and inspecting a multi-stage rolling mill according to claim 7, When the inner housing includes an upper inner housing provided above the metal strip and a lower inner housing provided below the metal strip, The method further includes the step of moving the lower inner housing in a width direction of the metal strip. Maintenance and inspection methods for multi-stage rolling mills.

10. A method for using the multi-stage rolling mill according to claim 1, comprising: When the leading end of the metal strip is threaded between the pair of work rolls, the coolant spray header is moved in the rolling direction and / or the counter-rolling direction to approach the pair of work rolls. How to use a multi-stage rolling mill.

11. The method of using a multi-stage rolling mill according to claim 10, During normal rolling of the metal strip, the coolant spray header is moved away from the pair of work rolls when the leading end is threaded. How to use a multi-stage rolling mill.

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