Looper equipment, hot-rolled strip pickling equipment, and hot-rolled strip pickling method

Abstract

The present invention provides a looper facility capable of suppressing defects in a steel sheet even if the steel sheet meanders to such an extent that the steel sheet comes into contact with the looper facility. The looper facility of the present invention includes a plurality of conveying rolls, at least one fixed roll, a frame, at least one looper parker, and one or more pairs of vertical rolls provided at specific positions.

Description

[Technical field]

[0001] The present invention relates to a looper system, and a hot-rolled strip pickling system and a hot-rolled strip pickling method using the looper system. [Background technology]

[0002] In order to continuously perform various treatments on steel sheets, looper equipment is used to transport steel sheets while storing them at an appropriate length. For example, when thin steel sheets with a thickness of a few mm or less are subjected to pickling treatment in a continuous line, the tail end of the preceding steel sheet and the head end of the succeeding steel sheet are first welded by a welding device, and then the steel sheets are fed to a pickling device via an annealing furnace and a cooling zone, and pickling of the steel sheets is continuously performed. In this case, the steel sheet is stopped from passing during welding, but is passed through during pickling for continuous treatment, so the amount of steel sheet (passing length) between the welding device on the upstream side of the line and the pickling device on the downstream side changes from time to time. Therefore, a looper equipment capable of adjusting the amount of steel sheet stored is provided between such an upstream device and a downstream device, thereby enabling continuous treatment of the steel sheets.

[0003] FIG. 1A shows a perspective view of a typical looper equipment as seen from above. Usually, the looper equipment 1 has a rail-like platform 5 supported by platform legs 51 at an arbitrary height from the floor surface along the longitudinal direction, and a looper car (not shown) moves along the platform 5 in the conveying direction or in the opposite direction to adjust the amount of steel sheets stored. The platform 5 and the platform legs 51 form the side walls of the looper equipment 1, and together with the floor surface, define a conveying area surrounded by a substantially concave shape. Within this conveying area, one platform 5 in the width direction of the steel sheet 2 and the other platform 5 rotatably support one end and the other end of a conveying roll 3 having a rotation axis extending in the width direction of the steel sheet 2, respectively. The steel sheet 2 advances to the depth of the paper of FIG. 1A while being sent to the multiple conveying rolls 3 within the concave conveying area and under the looper car.

[0004] In such looper equipment, due to various factors such as changes in the looper length, which is the amount of stored steel sheet, deviations in tension on the steel sheet, or unevenness in the shape of the steel sheet, the steel sheet 2 may meander during transportation as illustrated in Fig. 1B. When the steel sheet 2 meanders during transportation in this manner, the steel sheet 2 may interfere with the stand 5 constituting the side wall, particularly the stand legs 51, causing so-called guide defects in the shape of the edge of the steel sheet 2 in the width direction, or the steel sheet 2 may roll out due to guide defects on the outer periphery of the coil when it is wound up.

[0005] In response to this, Patent Document 1 discloses a technique for suppressing tension deviation and preventing meandering of the metal strip by adjusting roll drive control within a looper.

[0006] Patent Document 2 discloses a technique for correcting the shape of a hot-rolled steel sheet by pressing it with a roll after pickling.

[0007] Patent Document 3 discloses a technique for preventing meandering of a steel strip by adjusting a control unit in a steering roll.

[0008] Patent Document 4 discloses a technique for preventing meandering in a metal strip winding facility by providing side guides on the sides and pressing the metal strip from above with rolls. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2009-233698 A [Patent Document 2] Japanese Patent Application Publication No. 11-57805 [Patent Document 3] Japanese Patent Application Publication No. 11-116114 [Patent Document 4] JP 2013-226589 A Summary of the Invention [Problem to be solved by the invention]

[0010] The above-mentioned conventional techniques are intended to straighten the shape of a steel sheet or suppress meandering of the steel sheet. However, the above-mentioned conventional techniques have some concerns, such as a small tension adjustment margin for preventing breakage of the steel sheet, the possibility of deformation or breakage of the steel sheet due to excessive straightening of the shape, and the difficulty of pressing down the steel sheet over the entire length of the looper. For these reasons, there is a limit to straightening the shape of the steel sheet and suppressing meandering, and there are cases where the steel sheet still significantly meanders even with the above-mentioned conventional techniques. In such a case, the side of the steel plate transported through the looper equipment may come into contact with the wall of the equipment, etc., causing a defect (guide defect) similar to rubbing on the side of the steel plate, resulting in a loss of yield.

[0011] In particular, the guide flaws are one of the main causes of production defects, for example, in a continuous pickling line for steel sheets, and may lead to breakage of the steel sheet during the pickling line. Furthermore, if a steel sheet with guide flaws is directly fed to the next processing step, for example, a cold rolling machine, the steel sheet may break at high speed during the cold rolling line, causing serious damage. Therefore, when continuously performing the desired processing on the steel sheet, it is important to store and transport the steel sheet while suppressing the guide flaws.

[0012] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide a looper equipment that can suppress the occurrence of defects in a steel sheet even when the steel sheet being transported on a continuous processing line significantly meanders to the extent that it comes into contact with the looper equipment. Another object of the present invention is to provide a hot-rolled sheet pickling facility and a hot-rolled sheet pickling method that use such looper equipment to continuously pickle a hot-rolled sheet while suppressing the occurrence of defects in the hot-rolled sheet. [Means for solving the problem]

[0013] The present inventors have thoroughly studied the causes of defects occurring in a steel sheet due to contact of the steel sheet with the looper equipment during transportation. As a result, referring to the example of Fig. 1B, for example, when a part of a steel sheet 2 transported in the looper equipment 1 has a defective shape, the transport direction of the steel sheet 2 starts to locally deviate from the longitudinal direction, and as the transport continues, the deviation gradually increases, causing a noticeable meandering of the steel sheet 2. Then, the inventors have found that the contact of the meandering steel sheet 2 with the stand 5, particularly the stand leg 51, causes guide defects in the steel sheet 2. Based on this finding, the inventors further investigated a structure capable of preventing a steel plate from coming into contact with the rack even if the steel plate is meandering while being transported within the looper equipment, and completed the present invention.

[0014] That is, the gist of the present invention is as follows. [1] A looper facility capable of storing and transporting steel plates in a longitudinal direction, A plurality of conveying rolls are provided at intervals in the longitudinal direction so that their rotation axes extend in the width direction of the steel plate, and support one side of the steel plate; At least one fixed roll provided at one end in the longitudinal direction; A stand is provided on both sides of the steel plate in the width direction and extending in the longitudinal direction; At least one looper parker is provided at the other end in the longitudinal direction and is capable of adjusting the amount of the steel plate stored by moving along the frame, a pair of vertical rolls each having a rotation axis extending in the thickness direction of the steel plate and rotatable along a conveying direction of the steel plate, the pair of vertical rolls being provided at positions sandwiching the steel plate in the width direction and at a distance from the steel plate that is smaller than a distance between the steel plate and the frame, the pair of vertical rolls having a rotation axis extending in the thickness direction of the steel plate and rotatable along a conveying direction of the steel plate.

[0015] [2] The vertical roll is supported by a bearing, The looper equipment described in [1] above, further comprising a guard that covers a gap between the bottom surface of the vertical roll and the bearing.

[0016] [3] The looper equipment according to [1] or [2] above, wherein two or more pairs of the vertical rolls are provided, and the installation interval between the vertical rolls in the longitudinal direction is 10 m or less.

[0017] [4] The steel sheet is a hot-rolled sheet for an electromagnetic steel sheet, The looper facility according to any one of [1] to [3] further includes a pickling device capable of pickling the hot-rolled sheet downstream in the conveying direction, The hot-rolled sheet pickling facility is configured so that the hot-rolled sheet can be supplied to the pickling device via the looper facility.

[0018] [5] The steel sheet is a hot-rolled sheet for manufacturing an electromagnetic steel sheet, A method for pickling a hot-rolled sheet, comprising: supplying the hot-rolled sheet through a looper facility described in any one of [1] to [3] above to a pickling device provided downstream of the looper facility in the conveying direction, thereby subjecting the hot-rolled sheet to a pickling treatment. Effect of the Invention

[0019] According to the present invention, it is possible to provide a looper equipment that can effectively reduce the occurrence of defects in a steel sheet even if the transported steel sheet meanders to the extent that it comes into contact with the looper equipment. Furthermore, according to the present invention, it is possible to provide a hot-rolled sheet pickling system and a hot-rolled sheet pickling method capable of continuously pickling a hot-rolled sheet while effectively reducing the occurrence of defects in the hot-rolled sheet. The present invention is particularly useful for thin steel plates having a thickness of 2.7 mm or less. [Brief description of the drawings]

[0020] [Figure 1A] FIG. 1 is a schematic perspective view showing a part of a typical looper system when a steel sheet is being normally transported. [Figure 1B] FIG. 1 is a schematic perspective view showing a part of a general looper installation in which a steel sheet meanders. [Diagram 2] FIG. 1 is a schematic side view showing a typical looper system. [Diagram 3]FIG. 2 is a side schematic view showing an example of the looper equipment of the present invention. [Figure 4] FIG. 2 is a plan view showing the position of vertical rolls in one embodiment of the present invention. [Diagram 5] FIG. 11 is a schematic plan view showing the position of vertical rolls in another embodiment of the present invention. [Figure 6] FIG. 11 is a schematic plan view showing the position of vertical rolls in another embodiment of the present invention. [Figure 7A] FIG. 2 is a side view schematic diagram showing a vertical roll in one embodiment of the present invention. [Figure 7B] FIG. 2 is a front schematic view showing a vertical roll in one embodiment of the present invention. [Figure 7C] FIG. 2 is a schematic plan view showing a vertical roll in one embodiment of the present invention. [Figure 8] FIG. 1 is a side schematic view showing an example of a hot-rolled strip pickling facility of the present invention. [Figure 9] FIG. 2 is a schematic plan view showing various changes in the installation interval between vertical rolls in the examples. [Figure 10] 1 is a graph showing the results of Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] (looper equipment) The looper equipment of the present invention is capable of storing and transporting a steel sheet in the longitudinal direction, and includes a plurality of transport rolls, at least one fixed roll, a frame, at least one looper car, and one or more pairs of vertical rolls provided at specific positions. The looper equipment of the present invention may have any other configuration in addition to the above configuration. Since the looper equipment of the present invention has the above-mentioned configuration, particularly the vertical rolls, it is possible to continuously apply the desired processing to the steel sheet while effectively suppressing the occurrence of guide scratches on the steel sheet, regardless of, for example, fluctuations in the amount of steel sheet accumulated (passing length), conveying direction, and conveying speed between the welding device and the processing device. Hereinafter, a looper system according to an embodiment of the present invention will be described with reference to the drawings. All of the system configurations shown in the drawings in this specification are schematic, and therefore the present invention is not limited to the configurations and dimensions exemplified in the drawings.

[0022] [Transport roll] 1A and 1B are perspective views of a typical looper facility as seen from the front and diagonally above, which is the front side in the conveying direction, as described above, and Fig. 2 is a side view of the typical looper facility as seen from one side in the width direction of the steel plate. The looper equipment 1 has any number of conveying rolls (also called table rolls, or horizontal rolls when the steel plate is conveyed horizontally) 3. Each conveying roll 3 is provided so that its rotation axis extends in the width direction of the steel plate 2. The conveying rolls 3 are provided at any interval in the longitudinal direction, for example, spaced apart by about 3 m. The conveying rolls 3 support one side of the steel plate 2, or the lower side when the steel plate is conveyed horizontally, while rotating along the conveying direction of the steel plate 2, thereby conveying the steel plate 2.

[0023] [Fixed roll and looper] The looper equipment 1 also has at least one fixed roll (also called a steering roll) 4 provided at one end in the longitudinal direction, and at least one looper (the figure mainly shows a looper roll) 6 provided at the other end in the longitudinal direction. The longer the looper is, the greater the adjustment margin for the storage amount of the steel sheet is. On the other hand, the longer the distance from the fixed roll 4 to the looper 6, the greater the possibility that the steel sheet 2 will meander. Therefore, it is preferable to provide one or more fixed rolls 4 at a distance of about 100 m to 150 m in the longitudinal direction. It is preferable to provide the looper cars 6 in a number equal to the total number of the fixed rolls 4 minus 1 or the same number as the total number of the fixed rolls 4, depending on the traveling direction of the steel sheet 2 at the outlet of the looper equipment 1.

[0024] [Mounting] By moving the looper parker 6 along the frame 5, that is, by moving the looper parker 6 parallel to the conveying direction, the amount of the steel sheet 2 being conveyed in the longitudinal direction between the fixed roll 4 and the looper parker 6 can be adjusted to a desired amount at any time. The pedestals 5 are provided on both sides of the width of the steel plate 2, extending in the longitudinal direction. Referring also to Fig. 4, the pedestals 5 are usually provided so as to sandwich the steel plate 2, which is normally transported, in the width direction at an arbitrary distance D. The greater the distance D, the less likely the meandering steel plate will collide with the pedestals, so the distance D is preferably 150 mm or more. Moreover, if the distance D is too large, the width of the steel plate becomes narrow, which reduces the production capacity per unit time, so the distance D is preferably 370 mm or less.

[0025] As described above, the frame 5 may be supported by frame legs 51 provided at any interval in the longitudinal direction, whereby the rail portion of the frame 5 can be provided at a height equal to the height of the frame legs 51 above the bottom surface of the looper equipment. Referring also to Fig. 4, the arbitrary distance D1 between the frame legs 51 and the steel plate 2 is usually the same as the above-mentioned distance D between the frame 5 and the steel plate 2, and the preferable range of the distance D1 is also the same as that for the distance D of the frame 5. The steel plate 2 is usually transported at a height between the height of the transport rolls 3 and the height of the frame 5 or the frame legs 51.

[0026] [Vertical roll] The looper equipment further has one or more pairs of vertical rolls at positions sandwiching the width direction of the steel sheet. Referring also to the example of Fig. 4, a pair of vertical rolls 7 can be provided on one side of a stand 5 in the width direction of the steel sheet 2 and on the other side of a stand 5 so as to face each other in the width direction of the steel sheet 2. The vertical rolls 7 may be paired at positions sandwiching the width direction of the steel sheet 2, shifted by any distance in the longitudinal direction, as shown in Fig. 5, for example.

[0027] Returning to the example in Fig. 4, the vertical rolls 7 are also provided at a position where the distance d from the steel plate 2 is smaller than the distance D between the steel plate 2 and the frame 5, that is, so as to satisfy the relationship D>d. Similarly, the vertical rolls 7 are also provided at a position where the distance D1 from the steel plate 2 to the frame leg 51 satisfies the relationship D1>d. Here, the distance D (or D1) refers to the distance between the normally transported steel plate 2 and the stand 5 (or stand leg 51) in the width direction (horizontal) of the steel plate when viewed from one side in the thickness direction of the steel plate (see FIG. 4). Also, the distance d refers to the distance between the normally transported steel plate 2 and the vertical rolls 7 in the width direction (horizontal) of the steel plate when viewed from one side in the thickness direction of the steel plate (see FIG. 4). In other words, the vertical rolls 7 are provided so that the outer circumferential surface of the vertical rolls is located inside the transport area further inside than the stand 5 including the stand leg 51.

[0028] By providing the vertical rolls so as to satisfy the above-mentioned predetermined relationship, when the conveyed steel sheet meanders significantly, the steel sheet comes into contact with the vertical rolls instead of the frame and the frame legs, thereby reducing the frictional force when the steel sheet comes into contact with the looper equipment and suppressing the occurrence of defects in the steel sheet. The penetration length (Dd) of the vertical rolls into the inside of the conveying area is preferably 10 mm or more, and more preferably 30 mm or more. If the penetration length of the vertical rolls is shorter than the above lower limit, the possibility that the steel sheet will come into contact with the frame when the steel sheet meanders increases. On the other hand, if the penetration length is too large, the frequency of the steel sheet coming into contact with the vertical rolls increases even if the steel sheet is conveyed normally or the degree of meandering is small. If the steel sheet comes into contact with the vertical rolls frequently, the wear of the vertical rolls may progress, so the penetration length is preferably (width of conveying area-maximum width of steel sheet) x (1 / 20) or less. Here, the width of the transport area is the distance between one stand in the width direction of the steel plate and the other stand in the width direction. In other words, the recessed length is preferably D×(1 / 10) or less. With respect to the frame legs 51, in order to avoid contact with the steel sheet, the intrusion length (D1-d) of the vertical rolls into the conveying area is preferably 10 mm or more, and more preferably 30 mm or more.

[0029] As long as the vertical rolls are provided so as to satisfy the relationship D>d, the vertical rolls may be provided with different penetration lengths in the longitudinal direction and / or width direction, as shown in Fig. 6. For example, in a location where a frame leg is present near the vertical roll and the risk of contact with the steel sheet is relatively high, it is preferable to set the penetration length of the vertical roll at that location to be longer than the penetration length at other locations. From this viewpoint, it is preferable to set the penetration length (Dd) of the vertical roll at that location to 30 mm or more, and more preferably to set (D1-d) to 30 mm or more.

[0030] Further, referring to the examples of Figs. 3 and 4, the vertical rolls 7 have a rotation axis extending in the thickness direction of the steel sheet 2 and are rotatable along the conveying direction of the steel sheet. As a result, when the conveyed steel sheet 2 meanders and comes into contact with the vertical rolls 7, the vertical rolls 7 rotate to help the steel sheet 2 continue to be conveyed. This reliably reduces the frictional force on the steel sheet when it comes into contact with the looper equipment, and suppresses the occurrence of scratches on the steel sheet. In addition, even if the steel sheet meanders significantly, it is possible to continue conveying while suppressing guide scratches, so that the yield in the continuous line equipment can be significantly improved. From the above viewpoint, the shape of the vertical roll is preferably cylindrical.

[0031] The vertical rolls 7 are preferably supported by the frames 5. By supporting the vertical rolls by the frames on both sides in the width direction of the steel sheet, the vertical rolls can be well fixed and contact of the steel sheet with the frames can be more effectively suppressed.

[0032] Referring again to the examples of Figs. 4 and 5, the vertical rolls 7 can be installed in two or more pairs at any interval S along the longitudinal direction (conveying direction) of the steel sheet 2. The installation interval S of the vertical rolls 7 is not particularly limited as long as the adjacent vertical rolls do not come into contact with each other and their rotation is not hindered. Therefore, the lower limit of the installation interval S of the vertical rolls 7 can be set to be greater than the diameter of the vertical rolls (i.e., the gap between adjacent vertical rolls is greater than 0 m) when the diameters of the adjacent vertical rolls are equal, for example. However, the smaller the installation interval S, the greater the number of vertical rolls, which increases the effort and cost of installation, so the installation interval S of the vertical rolls 7 is preferably 2.0 m or more, and more preferably greater than 2.5 m. The installation interval S of the vertical rolls refers to the distance in the longitudinal direction between the rotation axis of one vertical roll and the rotation axis of the other vertical roll adjacent to each other in the longitudinal direction (see Figs. 4 and 5).

[0033] On the other hand, if the installation interval S of the vertical rolls 7 is widened, the possibility that the meandering steel sheet 2 will come into contact with the frame 5 increases. According to the study by the present inventors, meandering of the steel sheet is relatively likely to occur at the longitudinal end. If the end of the steel sheet comes into contact with the frame and a flaw occurs, the defective end can be cut off prior to the next process (for example, the cold rolling process). In this way, the upper limit of the installation interval S of the vertical rolls 7 can be determined from the length that is permissible in each process for the occurrence of flaws in the steel sheet and the amount of cutting caused by the flaws. From this viewpoint, the installation interval S of the vertical rolls 7 is preferably 10 m or less, more preferably less than 7.5 m, and even more preferably 5 m or less.

[0034] As described above, according to the study by the inventors, meandering of the steel sheet is relatively likely to occur at the longitudinal end portion. More specifically, according to the findings by the inventors, meandering of the steel sheet is likely to start between the exit side of the fixed roll and the first transport roll. In addition, when a welding device is provided upstream of the looper system, the steel sheet is likely to meander near the welding device. From these viewpoints, the pair of vertical rolls 7 located at the most upstream in the conveying direction are preferably provided between the fixed roll 4 and the conveying roll 3 located at the most upstream, as exemplified in Fig. 3, and more preferably provided at a position closer to the conveying roll 3 than the fixed roll 4. This makes it possible to efficiently suppress the occurrence of meandering at the inlet side of the looper facility.

[0035] The vertical rolls are preferably supported by bearings. Referring to the example of FIG. 7, one end of the vertical roll 7 in the rotation axis direction is rotatably supported by a bearing 71, and the bearing 71 can be installed, for example, on the floor surface of the conveying area in the looper equipment. FIG. 7A shows a side view of the vertical roll 7 and the bearing 71 as seen from one side in the width direction of the steel plate. FIG. 7B shows a front view of these as seen from the front side in the conveying direction of the steel plate, and a stand can be located on the right side of the paper in FIG. 7B, and a steel plate can be located on the left side of the paper. FIG. 7C shows a plan view of these as seen from one side of the surface of the steel plate, and a stand can be located on the right side of the paper in FIG. 7C, and a steel plate can be located on the left side of the paper. The rotation axis of the vertical roll 7 and the center line of the bearing 71 are usually on the same line, and therefore, a suitable installation position of the bearing 71 can follow the suitable installation position for the vertical roll 7 described above. This allows the vertical roll to be firmly fixed at a predetermined position in the looper equipment, and the occurrence of guide scratches in the steel plate conveyed in the looper equipment can be effectively prevented.

[0036] The material of the vertical roll is preferably a material that is not easily worn when it comes into contact with the steel sheet and is not easily scratched when it comes into contact with the steel sheet, and more preferably a metal having heat resistance and wear resistance. From the viewpoint of excellent wear resistance, chromium steel is more preferable. An example of a composition of the vertical roll that is preferably used contains Cr: 1.30% to 1.60%. It is more preferable to further contain one or two of C: 0.95% to 1.10% and Si: 0.15% to 0.35%. It is more preferable to further contain one or more selected from the group consisting of Mn: more than 0% and 0.50% or less, P: more than 0% and 0.025% or less, and S: more than 0% and 0.025% or less. There is no particular limitation, and the balance can be Fe and unavoidable impurities. Here, the above percentages are by mass. The suitable material for the bearing can also follow the vertical roll.

[0037] The size of the vertical roll is preferably such that it does not interfere with the looper car, the stand including the stand legs and the looper car rail, and the steel plate being normally conveyed. Specifically, the diameter of the vertical roll is preferably 50 mm or more and 150 mm or less.

[0038] The height of the vertical rolls is preferably set to a height that can sufficiently cover the expected range of heights at which the steel sheet may meander, for example, the range of heights at which interference marks with the steel sheet have been confirmed in a preliminary study. Specifically, the height of the vertical rolls is preferably 170 mm or more and 300 mm or less. Above the vertical rolls, looper cars usually move along the frame. Therefore, it is preferable to set the upper limit of the height of the vertical rolls in the rotation axis direction to a position lower than the lower limit of the height of the looper car moving on the frame rail in the rotation axis direction. With reference to the example of Fig. 7A, the downward separation distance d2 of the vertical rolls 7 with respect to the looper car 6 is arbitrary, but from the viewpoint of more reliably avoiding the interference of the vertical rolls 7 with the looper car 6, it is preferable to set d2 in the range of more than 0 mm and not more than 100 mm. From the viewpoint of better preventing the meandering steel sheet from contacting the frame, it is preferable to set the upper limit of the height in the rotational axis direction of the vertical rolls to a position above the upper limit of the height in the rotational axis direction of the support member for the vertical rolls. With reference to the example of Fig. 7A, for example, when the vertical rolls 7 are supported by the frame 5 (i.e., the frame is the support member), it is preferable to set the upward separation distance d3 of the vertical rolls 7 from the frame 5 to more than 0 mm, and more preferably to 3 mm or more. Therefore, the preferred range of the height of the vertical roll in the direction of its rotation axis can be above the upper limit of the height of the stand 5 and below the lower limit of the height of the looper car (both d2 and d3 exceed 0 mm).

[0039] [guard] As a result of further investigation by the present inventors, as shown in FIG. 7, a gap may be generated between the vertical roll 7 and the bearing 71 due to the structure. Depending on the position of the gap, the meandering steel sheet may enter the gap, causing serious defects in the steel sheet. It was found that the above problem may occur particularly when a thin steel sheet having a thickness of 2.7 mm or less and / or a steel sheet having a so-called edge stretch in which a wavy shape defect occurs at the width direction end of the steel sheet is used. Therefore, it was further found that it is preferable to further provide a guard 72 so as to cover the gap between the bottom surface of the vertical roll 7 and the upper surface of the bearing 71 when there is a possibility that the steel sheet may enter the gap. The guard preferably has a height and thickness sufficient to cover the gap. The shape of the guard is not particularly limited, and may be formed on the plate-like side surface of a rectangular prism such as a square prism as shown in Fig. 7C, or may be formed on the side surface of a cylinder having an arc-shaped cross section along the outer periphery of the vertical roll 7.

[0040] The method of installing the guard is not particularly limited as long as it does not hinder the rotation of the vertical roll, and for example, the guard can be supported by the wall surface of the frame. In the example shown in Figures 7B and 7C, the vertical roll 7 and the bearing 71 are provided in the space of the guard 72 toward the steel plate (not shown) being transported on the left side of the drawing so that the guard 72 is supported by the wall surface (not shown) of the frame on the right side of the drawing. In this way, by providing the looper equipment with an additional guard, it is possible to avoid or reduce serious defects caused by the steel sheet getting stuck in the gap between the vertical roll and the bearing.

[0041] By adopting the above-mentioned specific vertical rolls, when the steel sheet meanders, the side surface of the steel sheet comes into contact with the vertical rolls instead of interfering with equipment such as a frame or a wall. In response to this contact, the vertical rolls rotate in the same direction as the conveying direction, thereby mitigating the impact on the side surface of the steel sheet. In this way, it is possible to effectively prevent defects (guide scratches) from occurring on the side surface.

[0042] [Other configurations] The looper equipment may have other components in addition to the components described above, as long as the effects of the present invention are not impaired. The other components are not particularly limited, and examples thereof include a surveillance camera, various control devices, and detectors.

[0043] (Hot-rolled strip pickling equipment and hot-rolled strip pickling method) In the hot-rolled sheet pickling equipment of the present invention, the steel sheet is a hot-rolled sheet for an electromagnetic steel sheet, and a pickling device capable of pickling the hot-rolled sheet is further provided downstream in the conveying direction of the above-mentioned looper equipment, and the hot-rolled sheet is supplied to the pickling device via the above-mentioned looper equipment. In addition, in the hot-rolled sheet pickling method of the present invention, the steel sheet is a hot-rolled sheet for manufacturing an electromagnetic steel sheet, and the hot-rolled sheet is subjected to pickling treatment by supplying the hot-rolled sheet via the above-mentioned looper equipment to a pickling device provided downstream of the looper equipment in the conveying direction. The hot-rolled strip pickling equipment and the hot-rolled strip pickling method of the present invention may further include other devices and other steps, respectively. The hot-rolled strip pickling plant and the hot-rolled strip pickling method of the present invention utilize the above-mentioned looper plant, and therefore can obtain the same effects as those obtained by the looper plant of the present invention. Therefore, the defect rate in the looper plant can be reduced, and the hot-rolled strip can be pickled continuously and satisfactorily with a high yield.

[0044] The hot-rolled sheet pickling equipment and the hot-rolled sheet pickling method of the present invention are intended for hot-rolled sheets for manufacturing electromagnetic steel sheets. Hot-rolled sheets for electromagnetic steel sheets are brittle materials that are difficult to shape and tend to meander due to lateral bending and shape defects, so the effects of the present invention can be efficiently obtained.

[0045] A hot-rolled strip pickling plant and a hot-rolled strip pickling method according to an embodiment of the present invention will be described with reference to an example of Fig. 8. The hot-rolled strip pickling plant 10 further includes a pickling device 13 capable of pickling the hot-rolled strip 2, located downstream in the conveying direction of the above-mentioned predetermined looper facility. The hot-rolled strip 2 is supplied to the pickling device 13 via the above-mentioned predetermined looper facility. This allows the hot-rolled strip 2, which has a good shape and in which guide defects are suppressed, to be continuously subjected to a good pickling treatment with a good yield.

[0046] The pickling may be performed only with continuous pickling without annealing, or may be performed after annealing. With reference to the example of Fig. 8, when annealing is performed before pickling, an annealing furnace (annealing device) 11, or an annealing furnace 11 and a cooling zone (cooling device) 12 may be further provided as other devices downstream in the conveying direction of the above-mentioned predetermined looper equipment and upstream of the pickling device 13, in that order from the upstream side. Similarly, an annealing treatment, or an annealing treatment and a cooling treatment may be further performed in this order from the upstream side, as another process downstream of the above-mentioned specified looper equipment in the conveying direction and prior to the pickling treatment (upstream of the pickling treatment).

[0047] In addition, a shearing device (not shown) and a welding device (not shown) may be further provided as other devices on the upstream side in the conveying direction of the above-mentioned predetermined looper equipment. A preferred hot-rolled strip pickling equipment includes, in order from the upstream side in the conveying direction, a shearing device, a welding device, the above-mentioned looper equipment, an annealing device, a cooling device, and a pickling device. Similarly, a shearing process and a welding process may be further performed as other processes on the upstream side in the conveying direction from the above-mentioned predetermined looper facility. In a preferred hot-rolled strip pickling method, a shearing process, a welding process, a process of storing and conveying the steel sheet by the above-mentioned looper facility, a annealing process, a cooling process and a pickling process are performed in this order from the upstream side in the conveying direction. As described above, steel sheets have a tendency to meander at the welded portions. However, if welding is performed through a specified looper facility, continuous processing can be performed with a higher yield and in a satisfactory manner.

[0048] Furthermore, a cold rolling device (not shown) may be further provided as another device downstream in the conveying direction from the above-mentioned pickling device. Similarly, a cold rolling process may be further carried out as another process downstream in the conveying direction from the above-mentioned pickling process. As described above, high-speed fracture of a hot-rolled sheet during the cold rolling process due to guide defects causes severe damage. However, if the hot-rolled sheet is passed through a specified looper facility to reach the cold rolling stage, continuous processing can be performed with a higher yield and in a satisfactory manner.

[0049] In the hot-rolled strip pickling equipment and hot-rolled strip pickling method according to the present invention, items not described in this specification can all use the configuration (device) of a publicly known hot-rolled strip pickling equipment and the conventional method of pickling a hot-rolled strip. EXAMPLES

[0050] The present invention will be described in more detail below with reference to examples, although the present invention is not limited to these examples. Example 1 As shown in FIG. 9, in the looper equipment 1, the installation interval S in the longitudinal direction of the vertical rolls 7 was variously changed to transport a hot-rolled sheet for manufacturing an electrical steel sheet having a thickness of 2 mm and a length of 900 m as the steel sheet 2. The material of the vertical roll 7 used was chrome steel (C: 1.0%, Si: 0.2%, Mn: 0.3%, P: 0.02%, S: 0.02%, Cr: 1.4%, the remainder being Fe and unavoidable impurities). The vertical roll 7 was cylindrical, with a diameter of 110 mm and a height of 230 mm. The vertical roll 7 was supported by a bearing 71 fixed to the floor surface, and was further supported by a frame 5 on both sides in the longitudinal direction and on the back side (the side in the width direction that does not face the steel sheet) so as to be rotatable, as shown in FIG. 7A. In this embodiment, no guard was attached to the vertical roll 7.

[0051] Although not shown in Fig. 9, the pair of vertical rolls 7 located at the most upstream in the transport direction were provided between the fixed roll and the transport roll located at the most upstream, and closer to the transport roll than the fixed roll. Specifically, the distance between the pair of vertical rolls 7 located at the most upstream in the transport direction and the fixed roll was 10 m, and the distance between the pair of vertical rolls 7 located at the most upstream in the transport direction and the transport roll located at the most upstream was 1 m.

[0052] The distance D between the steel plate 2 and the stand 5 was set to 156 mm, and the distance D1 between the steel plate 2 and the stand leg 51 was also set to 156 mm, and the distance d between the vertical rolls 7 and the steel plate 2 was set to 141 mm. Therefore, the intrusion lengths (Dd) and (D1-d) of the vertical rolls 7 into the conveying area were both 15 mm. The width of the conveying area was 1.6 m, and the maximum width of the steel plate was 1.3 m. 7A, the downward separation distance d2 of the vertical roll 7 from the looper car 6 was set to 100 mm. Moreover, the upward separation distance d3 of the vertical roll 7 from the frame 5 was set to 30 mm.

[0053] Although not shown in FIG. 9, this looper equipment 1 also has a plurality of conveying rolls that are arranged at 3 m intervals in the longitudinal direction so that their rotation axes extend in the width direction of the steel plate 2 and support the underside of the steel plate 2; three fixed rolls arranged at one end in the longitudinal direction; and two looper parkers that are arranged at the other end in the longitudinal direction and can move along a stand 5 to adjust the amount of steel plate 2 stored therein.

[0054] The vertical rolls 7 paired in the width direction of the steel plate 2 were arranged facing each other without any longitudinal deviation with respect to the width direction, as shown in Fig. 9. The vertical rolls were arranged in a frame section having a total length of 150 m. Here, the installation intervals S of the vertical rolls 7 in the longitudinal direction were changed to 2.5 m, 5.0 m, 7.5 m, and 10 m, respectively. In the example of FIG. 9, for convenience, the installation intervals S: 2.5 m, 5.0 m, 7.5 m, and 10 m are shown on one line from the left side of the figure. However, in reality, the installation intervals S: 2.5 m (total of 60 pairs), 5.0 m (total of 30 pairs), 7.5 m (total of 20 pairs), and 10 m (total of 15 pairs) were each arranged on a different line, and one roll of the steel sheet 2 of the above length was transported for each of these installation intervals. In addition, for comparison, a case before the installation of the vertical rolls, i.e., a case without the vertical rolls, was also considered. Other conditions such as the conveying speed were the same as in the conventional methods.

[0055] The hot-rolled strip was transported through the looper equipment and wound into a coil, and the side of each coil was visually inspected over its entire length, and if even one guide defect was found, it was determined that a defect had occurred.Then, by conducting the same experiment for 3,000 coils, the defect (guide defect) occurrence rate was calculated according to the formula: defect occurrence rate (%) = number of coils with confirmed guide defects / total number of coils threaded x 100. The results are shown in Table 1.

[0056] [Table 1]

[0057] As shown in Table 1, it was confirmed that providing the looper equipment with the specified vertical rolls had the effect of reducing the defect rate of steel sheets. In addition, by adjusting the installation interval S of the vertical rolls, it was possible to reduce the defect rate by more than 40%, and even more than 50%, compared to the defect rate before the installation.

[0058] Example 2 The installation interval S of the vertical rolls 7 in the longitudinal direction was set to 2.5 m. In addition, guards as outlined in Figures 7A to 7C were further attached to all of the installed 60 pairs of vertical rolls. Except for the above, the defect occurrence rate of the hot-rolled sheet was obtained in the same manner as in Experiment 1. Here, the guard was in the form of a plate constituting the side surface of a rectangular pillar as exemplified in Fig. 7, with dimensions of 100 mm in height in the thickness direction of the steel plate and 200 mm in length in the longitudinal direction, and had a shape that covered the gap between the lower surface of the vertical roll and the bearing. The guard was installed by being supported by the wall surface of the frame at a distance of at least 10 mm from the vertical roll so as not to interfere with the rotation of the vertical roll.

[0059] Figure 10 shows the defect rate for hot-rolled strip transported through the looper equipment before and after the installation of the vertical rolls and guards. It was confirmed that the defect rate was further reduced after installation compared to before installation. Specifically, the defect rate was reduced by more than 60% compared to the defect rate before installation. In this way, it was confirmed that the defect occurrence rate of steel sheets can be further reduced by providing a predetermined guard to the vertical rolls.

[0060] Example 3 In Example 2, the guards were found to be effective in preventing further guide defects on the steel sheet, and thus guarded vertical rolls were used, in which the same guards as in Example 2 were provided on the vertical rolls. Moreover, the guards were installed at intervals S of 2.5 m, 5.0 m, 7.5 m, and 10 m, respectively, in the same manner as in Example 1. The defect occurrence rate in the hot-rolled sheet was determined in the same manner as in Example 1. The results are shown in Table 2.

[0061] [Table 2]

[0062] As shown in Table 2, it was confirmed that the defect occurrence rate of steel sheets could be further reduced by adding a specified guard to the vertical rolls. In addition, by adjusting the installation interval S of the vertical rolls, the defect occurrence rate could be reduced by more than 40%, more than 50%, and even more than 60% compared to the defect occurrence rate before the installation.

[0063] Example 4 The installation interval S of the vertical rolls in the longitudinal direction was set to 2.5 m (total of 60 pairs). The size of the vertical rolls was set to a diameter of 110 mm and a height of 170 mm. Furthermore, the hot-rolled sheet was supplied to a pickling device via a looper facility, and the hot-rolled sheet was subjected to pickling treatment. The defect occurrence rate of the hot-rolled sheet was obtained in the same manner as in Experiment 1 except for the above. As a result, the defect rate of the hot-rolled sheet after pickling was reduced from 0.52% before the installation of the vertical rolls to 0.24%. In this way, even when the vertical rolls were not fitted with guards and vertical rolls of different heights were installed, the effect of reducing the defect rate was confirmed. Furthermore, the effect of reducing the defect rate was also confirmed for the hot-rolled sheet after pickling. [Explanation of symbols]

[0064] 1 Looper equipment 10 Hot rolled plate pickling equipment 11 Annealing furnace (annealing equipment) 12 Cooling Zone (Cooling Equipment) 13 Pickling equipment 2 Steel plate (hot rolled plate) 3. Transport roll 4 Fixed Roll 5 Mounting 51 Frame legs 6 Looper (Looper Roll) 7 Vertical Roll 71 Bearings 72 Guard D Distance between the steel plate and the stand D1 Distance between the steel plate and the stand leg d Distance between steel plate and vertical roll d2 Distance between looper and vertical roll d3 Distance between the support member (frame) and the vertical roll S Vertical roll installation interval

Claims

1. A looper facility capable of storing and transporting steel plates in a longitudinal direction, A plurality of conveying rolls are provided at intervals in the longitudinal direction so that their rotation axes extend in the width direction of the steel plate, and support one side of the steel plate; At least one fixed roll provided at one end in the longitudinal direction; A stand is provided on both sides of the steel plate in the width direction and extending in the longitudinal direction; At least one looper parker is provided at the other end in the longitudinal direction and is capable of adjusting the amount of the steel plate stored by moving along the frame, a pair of vertical rolls each having a rotation axis extending in the thickness direction of the steel plate and rotatable along the conveying direction of the steel plate, the pair of vertical rolls being provided at a position sandwiching the steel plate in the width direction and at a position where the distance from the steel plate is smaller than the distance between the steel plate and the frame, the pair of vertical rolls having a rotation axis extending in the thickness direction of the steel plate and rotatable along the conveying direction of the steel plate.

2. The vertical roll is supported by a bearing, The looper equipment according to claim 1 , further comprising a guard covering a gap between a bottom surface of the vertical roll and the bearing.

3. The looper equipment according to claim 1, wherein two or more pairs of the vertical rolls are provided, and the installation interval between the vertical rolls in the longitudinal direction is 10 m or less.

4. The looper equipment according to claim 2, wherein two or more pairs of the vertical rolls are provided, and the installation interval between the vertical rolls in the longitudinal direction is 10 m or less.

5. The steel sheet is a hot-rolled sheet for an electromagnetic steel sheet, A pickling device capable of pickling the hot-rolled sheet is further provided downstream in the conveying direction of the looper facility according to any one of claims 1 to 4, The hot-rolled sheet pickling facility is configured so that the hot-rolled sheet can be supplied to the pickling device via the looper facility.

6. The steel sheet is a hot-rolled sheet for manufacturing an electromagnetic steel sheet, A hot-rolled sheet pickling method, comprising: supplying the hot-rolled sheet through the looper facility according to any one of claims 1 to 4 to a pickling device provided downstream of the looper facility in the conveying direction, thereby subjecting the hot-rolled sheet to a pickling treatment.