Looper installation, hot-rolled sheet pickling facility, and hot-rolled sheet pickling method

Abstract

Provided is a looper installation capable of inhibiting a defect of a steel sheet even when meandering occurs to an extent that the steel sheet comes into contact with the looper installation. A looper installation according to the present invention comprises: a plurality of conveyance rolls; at least one fixed roll; a frame; at least one looper car; and at least one pair of vertical rolls provided at a specific position.

Description

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

[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.

[0002] Looper equipment is used to transport steel sheets while storing them at an appropriate length in order to continuously perform various treatments on the steel sheets. For example, when thin steel sheets having a thickness of a few millimeters or less are subjected to pickling treatment on a continuous line, the tail end of a preceding steel sheet is first welded to the front end of a succeeding steel sheet using a welding device, and then the steel sheets are fed to an annealing furnace, a cooling zone, and then a pickling device, where the steel sheets are continuously pickled. In this case, the steel sheet threading is stopped during welding, but the steel sheet is threaded during pickling for continuous treatment. Therefore, the amount of steel sheet (threading length) between the welding device located upstream of the line and the pickling device located downstream changes as needed. 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 1, viewed obliquely from above. Typically, the looper equipment 1 has a rail-like platform 5 supported by platform legs 51 at a desired height from the floor, extending longitudinally. A looper car (not shown) moves along the platform 5 in the conveying direction or the opposite direction to adjust the amount of steel sheet stored. The platform 5 and platform legs 51 form the side walls of the looper equipment 1, and together with the floor, define a generally concave-shaped enclosed conveying area. Within this conveying area, the platform 5 on one side of the width of the steel sheet 2 and the platform 5 on the other side 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. The steel sheet 2 advances through the concave conveying area and below the looper car, being fed by the multiple conveying rolls 3, toward the depth of the page in FIG. 1A.

[0004] In such looper equipment, various factors such as changes in the looper length (i.e., the amount of steel sheet stored), deviations in tension on the steel sheet, or unevenness in the shape of the steel sheet may cause the steel sheet 2 to meander during transport, as exemplified in Fig. 1B. When the steel sheet 2 meanders during transport, 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.

[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 the 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 side surfaces and pressing the metal strip from above with rolls.

[0009] JP 2009-233698 JP 11-57805 JP 11-116114 JP 2013-226589

[0010] The above-mentioned conventional techniques are intended to straighten the shape of a steel sheet or to suppress meandering of the steel sheet. However, the above-mentioned conventional techniques have concerns such as a small allowance for tension adjustment to prevent breakage of the steel sheet, the risk of deformation or breakage of the steel sheet due to excessive shape straightening, and the difficulty of holding the steel sheet down over the entire length of the looper. For these reasons, there are limitations to the shape straightening of the steel sheet and the suppression of meandering, and even with the above-mentioned conventional techniques, there are cases in which the steel sheet still significantly meanders. In such cases, the side of the steel sheet transported through the looper equipment comes into contact with the wall of the equipment or the like, causing a defect (guide flaw) similar to rubbing on the side of the steel sheet, resulting in a loss of yield.

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

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

[0013] The present inventors have conducted extensive research into factors that cause defects in steel sheets due to contact with the looper equipment during transport. As a result, with reference to the example of Fig. 1B , for example, when a steel sheet 2 being transported through the looper equipment 1 has a defective shape in a portion thereof, the transport direction of the steel sheet 2 begins to locally deviate from the longitudinal direction, and as the transport continues, the deviation gradually increases, causing the steel sheet 2 to significantly meander. The inventors have then ascertained that contact of the meandering steel sheet 2 with the gantry 5, particularly with the gantry legs 51, causes guide defects in the steel sheet 2. Based on this finding, the present inventors have further researched a structure that can prevent contact with the gantry even when the steel sheet being transported through the looper equipment meanders, and have completed the present invention.

[0014] That is, the gist of the present invention is as follows: [1] A looper facility capable of transporting a steel plate in a longitudinal direction while storing it, comprising: a plurality of transport rolls arranged at intervals in the longitudinal direction so that their rotation axes extend in the width direction of the steel plate, and supporting one side of the steel plate, at least one fixed roll arranged at one end in the longitudinal direction, stands arranged on both sides in the width direction of the steel plate and extending in the longitudinal direction, and at least one looper parker arranged at the other end in the longitudinal direction and capable of adjusting the amount of steel plate stored by moving along the stands, characterized in that the looper facility further comprises one or more pairs of vertical rolls arranged at positions sandwiching the steel plate in the width direction and at a distance from the steel plate that is shorter than the distance between the steel plate and the stands, and whose rotation axes extend in the thickness direction of the steel plate and are rotatable along the transport direction of the steel plate.

[0015] [2] The looper equipment according to the above [1], wherein the vertical roll is supported by a bearing, and further comprising a guard covering 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 vertical rolls are provided, and the installation interval between the vertical rolls in the longitudinal direction is 10 m or less.

[0017] [4] The hot-rolled sheet pickling facility further comprises a pickling device capable of pickling the hot-rolled sheet, located downstream in the conveying direction of the looper facility described in any one of [1] to [3] above, wherein the steel sheet is a hot-rolled sheet for an electromagnetic steel sheet, and 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] A hot-rolled sheet pickling method, wherein the steel sheet is a hot-rolled sheet for manufacturing an electromagnetic steel sheet, and the hot-rolled sheet is subjected to a pickling treatment by supplying the hot-rolled sheet via the looper equipment described in any one of [1] to [3] above to a pickling device provided downstream of the looper equipment in the conveying direction.

[0019] According to the present invention, it is possible to provide a looper facility that can effectively reduce the occurrence of defects in a steel sheet even when the conveyed steel sheet meanders to the extent that it comes into contact with the looper facility. Furthermore, according to the present invention, it is possible to provide a hot-rolled sheet pickling facility and a hot-rolled sheet pickling method that can continuously pickle 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 sheets having a thickness of 2.7 mm or less.

[0020] FIG. 1 is a schematic perspective view showing a portion of a general looper facility, showing a case where a steel sheet is normally transported. FIG. 2 is a schematic perspective view showing a portion of a general looper facility, showing a case where a steel sheet is meandering. FIG. 3 is a schematic side view showing a general looper facility. FIG. 4 is a schematic side view showing an example of the looper facility of the present invention. FIG. 5 is a schematic plan view showing the position of vertical rolls in an embodiment of the present invention. FIG. 6 is a schematic plan view showing the position of vertical rolls in another embodiment of the present invention. FIG. 7 is a schematic side view showing vertical rolls in another embodiment of the present invention. FIG. 8 is a schematic front view showing vertical rolls in an embodiment of the present invention. FIG. 9 is a schematic plan view showing vertical rolls in an embodiment of the present invention. FIG. 10 is a schematic side view showing an example of hot-rolled strip pickling equipment of the present invention. FIG. 11 is a schematic plan view showing, in outline, how the installation intervals of the vertical rolls are variously changed in the examples. FIG. 12 is a graph showing the results of Example 2.

[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, and one or more pairs of vertical rolls provided at specific positions. The looper equipment of the present invention may optionally include other configurations in addition to the above configuration. By including the above configuration, particularly the vertical rolls, the looper equipment of the present invention can continuously perform a desired process on a steel sheet while effectively suppressing the occurrence of guide defects in the steel sheet, regardless of, for example, fluctuations in the storage amount (threading length), transport direction, and transport speed of the steel sheet between the welding device and the processing device. Hereinafter, a looper equipment according to one embodiment of the present invention will be described with reference to the drawings. All equipment configurations shown in the drawings in this specification are schematic, and therefore the present invention is not limited to the configurations and dimensions illustrated in the drawings.

[0022] 1A and 1B are perspective views of a typical looper apparatus as seen from the front and obliquely above, i.e., in the front of the conveying direction. FIG. 2 is a side view of a typical looper apparatus as seen from one side in the width direction of the steel sheet. The looper apparatus 1 has an arbitrary number of conveying rolls (also called table rolls, or also called horizontal rolls when the steel sheet is conveyed horizontally) 3. Each conveying roll 3 is provided so that its rotation axis extends in the width direction of the steel sheet 2. The conveying rolls 3 are also provided at an arbitrary interval in the longitudinal direction, for example, about 3 m apart. The conveying rolls 3 support one side of the steel sheet 2, or the lower side when the steel sheet is conveyed horizontally, and rotate along the conveying direction of the steel sheet 2, thereby conveying the steel sheet 2.

[0023] [Fixed Rolls and Looper Parkers] The looper equipment 1 also has at least one fixed roll (also referred to as a steering roll) 4 provided at one end in the longitudinal direction, and at least one looper parker (looper parker rolls are mainly shown in the figure) 6 provided at the other end in the longitudinal direction. The longer the looper, the wider the adjustment margin for the steel sheet storage amount. On the other hand, the longer the distance from the fixed roll 4 to the looper parker 6, the higher 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 approximately 100 m to 150 m in the longitudinal direction. It is preferable to provide looper parkers 6 in the number equal to or less than the total number of fixed rolls 4, depending on the traveling direction of the steel sheet 2 at the outlet of the looper equipment 1.

[0024] [Standing] By moving the looper parker 6 along the stand 5, that is, by moving the looper parker 6 parallel to the conveying direction, the amount of accumulated steel sheet 2 conveyed in the longitudinal direction between the fixed rolls 4 and the looper parker 6 can be adjusted to a desired amount at any time. The stands 5 are provided on both sides of the width of the steel sheet 2, extending in the longitudinal direction. Referring also to FIG. 4 , the stands 5 are usually provided so as to sandwich the steel sheet 2 being normally conveyed from the width direction, at a distance D. The greater the distance D, the less likely a meandering steel sheet 2 is to collide with the stand, so the distance D is preferably 150 mm or more. Furthermore, if the distance D is too large, the steel sheet becomes narrow, resulting in a decrease in production capacity per unit time, so the distance D is preferably 370 mm or less.

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

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

[0027] Returning to the example of 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 pedestal 5, i.e., so that the relationship D>d is satisfied. Similarly, the vertical rolls 7 are provided at a position where the distance D1 between the steel plate 2 and the pedestal leg 51 is also satisfied, so that the relationship D1>d is satisfied. Here, the distance D (or D1) refers to the distance between the normally transported steel plate 2 and the pedestal 5 (or the pedestal leg 51) in the width direction (horizontal) of the steel plate as viewed from one side in the thickness direction of the steel plate (see FIG. 4 ). 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 as 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 relative to the pedestal 5 including the pedestal leg 51.

[0028] By providing the vertical rolls so as to satisfy the above-described predetermined relationship, when the conveyed steel sheet meanders significantly, the steel sheet comes into contact with the vertical rolls instead of the frame and frame legs. This reduces the frictional force when the steel sheet comes into contact with the looper equipment, thereby suppressing defects on the steel sheet. The penetration length (D-d) of the vertical rolls into the conveying area is preferably 10 mm or more, more preferably 30 mm or more. This is because if the penetration length of the vertical rolls is shorter than the above-described lower limit, the steel sheet is more likely to come into contact with the frame when it meanders. On the other hand, if the penetration length is too large, the steel sheet will come into contact with the vertical rolls more frequently even when it is being conveyed normally or even when the degree of meandering is small. Frequent contact of the steel sheet with the vertical rolls may accelerate wear of the vertical rolls, so the penetration length is preferably (width of the conveying area - maximum width of the steel sheet) x (1 / 20) or less. Here, the width of the conveying region is the distance between one pedestal and the other pedestal in the width direction of the steel sheet. In other words, the penetration length is preferably D×(1 / 10) or less. With respect to the pedestal legs 51, in order to avoid contact with the steel sheet, the penetration length (D1-d) of the vertical rolls into the conveying region is preferably 10 mm or more, 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 (D-d) of the vertical roll at that location to 30 mm or more, and it is more preferable to set (D1-d) to 30 mm or more.

[0030] 3 and 4, the vertical rolls 7 have rotation axes extending in the thickness direction of the steel sheet 2 and 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 defects on the steel sheet. Furthermore, even if the steel sheet meanders significantly, it is possible to continue conveying while suppressing guide defects, which can significantly improve the yield in continuous line equipment. From the above viewpoints, the shape of the vertical rolls is preferably cylindrical.

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

[0032] Referring again to the examples of Figures 4 and 5, two or more pairs of vertical rolls 7 can be installed 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 adjacent vertical rolls do not come into contact with each other and their rotation is not hindered. Therefore, for example, when adjacent vertical rolls have the same diameter, the lower limit of the installation interval S of the vertical rolls 7 can be set to exceed the diameter of the vertical rolls (i.e., the gap between adjacent vertical rolls exceeds 0 m). However, since the smaller the installation interval S, the greater the number of vertical rolls, which increases the installation effort and cost, the installation interval S of the vertical rolls 7 is preferably 2.0 m or more, more preferably exceeding 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 Figures 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 cradle 5 increases. According to the study by the present inventors, meandering of the steel sheet is relatively likely to occur at the longitudinal end portions. If the steel sheet end portions come into contact with the cradle and cause defects, the defective end portions can be cut off prior to the next process (e.g., cold rolling process). In this way, the upper limit of the installation interval S of the vertical rolls 7 can be determined based on the length that is allowable for the occurrence of defects in the steel sheet and the resulting cut amount in each process. 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 present inventors, meandering of the steel sheet is relatively likely to occur at the longitudinal end portions. More specifically, according to the findings of the present inventors, meandering of the steel sheet is likely to begin between the outlet side of the fixed rolls and the first transport roll. Furthermore, 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, as illustrated in FIG. 3 , the pair of vertical rolls 7 located at the most upstream side in the transport direction are preferably provided between the fixed rolls 4 and the most upstream transport rolls 3, and more preferably, are provided at a position closer to the transport rolls 3 than the fixed rolls 4. This makes it possible to efficiently suppress the occurrence of meandering at the inlet side of the looper system.

[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 of the conveying area of ​​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 sheet. FIG. 7B shows a front view of these as seen from the front in the conveying direction of the steel sheet, with a stand positioned on the right side of the page and the steel sheet positioned on the left side of the page. FIG. 7C shows a plan view of these as seen from one side of the surface of the steel sheet, with a stand positioned on the right side of the page and the steel sheet positioned on the left side of the page. The rotation axis of the vertical roll 7 and the center line of the bearing 71 are usually on the same line. 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 within the looper equipment, and effectively prevents guide marks from occurring in the steel sheet being conveyed through the looper equipment.

[0036] The material of the vertical rolls is preferably a material that is resistant to wear and scratches when in contact with the steel sheet, and more preferably a metal having heat resistance and wear resistance. From the viewpoint of excellent wear resistance, chrome steel is even more preferable. An example of a suitable chemical composition of the vertical rolls 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 even more preferable to further contain one or more selected from the group consisting of Mn: more than 0% to 0.50%, P: more than 0% to 0.025%, and S: more than 0% to 0.025%. The balance is not particularly limited, and can be Fe and unavoidable impurities. Here, the above percentages are by mass. The suitable materials for the bearings can also follow the vertical rolls.

[0037] The size of the vertical rolls is preferably such that they do not interfere with the looper car, the stand including the stand legs and looper rails, and the steel sheet being normally conveyed. Specifically, the diameter of the vertical rolls is preferably 50 mm or more and 150 mm or less.

[0038] Furthermore, the height of the vertical rolls is preferably 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 traces of interference with the steel sheet were confirmed in a preliminary study. Specifically, the height of the vertical rolls is preferably 170 mm or more and 300 mm or less. Looper parkers usually move along a pedestal above the vertical rolls. Therefore, it is preferable to set the upper limit of the height of the vertical rolls in the rotational axis direction to a position lower than the lower limit of the height of the looper parker moving on the pedestal rail. Referring also to the example of FIG. 7A , the downward separation distance d2 of the vertical rolls 7 relative to the looper parker 6 is arbitrary. However, from the viewpoint of more reliably avoiding interference of the looper parker 6 with the vertical rolls 7, it is preferable to set d2 in the range of, for example, more than 0 mm and not more than 100 mm. From the viewpoint of more effectively preventing contact of the meandering steel sheet with the pedestal, it is preferable to set the upper limit of the height of the vertical rolls in the rotational axis direction to a position higher than the upper limit of the height of the support members of the vertical rolls in the rotational axis direction. 7A , for example, when the vertical roll 7 is supported by the pedestal 5 (i.e., the pedestal is a support member), the upward separation distance d3 of the vertical roll 7 with respect to the pedestal 5 is preferably set to more than 0 mm, and more preferably set to 3 mm or more. Therefore, a suitable range of the height of the vertical roll in the rotation axis direction of the vertical roll can be set to be above the upper limit of the height of the pedestal 5 and below the lower limit of the height of the looper car (both d2 and d3 are above 0 mm).

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

[0040] The method of installing the guard is not particularly limited as long as it does not interfere with the rotation of the vertical rolls, 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 rolls 7 and bearings 71 are provided in the space of the guard 72 closer to the steel plate (not shown) being conveyed 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 that would occur if the steel plate were to get stuck in the gap between the vertical roll and the bearing.

[0041] By employing the above-described predetermined 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 flaws) from occurring on the side surface.

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

[0043] (Hot-rolled sheet pickling equipment and hot-rolled sheet pickling method) In the hot-rolled sheet pickling equipment of the present invention, the steel sheet is a hot-rolled sheet for use in electrical steel sheets, and a pickling device capable of pickling the hot-rolled sheet is further provided downstream in the conveying direction of the looper equipment described above, and the hot-rolled sheet is supplied to the pickling device via the looper equipment. In the hot-rolled sheet pickling method of the present invention, the steel sheet is a hot-rolled sheet for use in manufacturing electrical steel sheets, and the hot-rolled sheet is subjected to pickling treatment by being supplied via the looper equipment to a pickling device provided downstream in the conveying direction of the looper equipment. The hot-rolled sheet pickling equipment and hot-rolled sheet pickling method of the present invention may further include other devices and other processes. Because the hot-rolled sheet pickling equipment and hot-rolled sheet pickling method of the present invention utilize the specified looper equipment described above, they can achieve the same effects as those achieved by the looper equipment of the present invention. Therefore, the defect rate in the looper equipment can be reduced, and the hot-rolled sheet can be continuously pickled well and with a high yield.

[0044] The hot-rolled sheet pickling equipment and hot-rolled sheet pickling method of the present invention are intended for hot-rolled sheets for manufacturing electrical steel sheets. Hot-rolled sheets for electrical steel sheets are brittle materials that are difficult to shape and are prone to meandering 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 one embodiment of the present invention will be described with reference to the 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 predetermined looper facility described above. The hot-rolled strip 2 is supplied to the pickling device 13 via the predetermined looper facility described above. This allows for continuous, good pickling treatment with a high yield to be performed on the hot-rolled strip 2 having a good shape and suppressed guide defects.

[0046] Regarding pickling, continuous pickling may be performed without annealing, or continuous pickling may be performed after annealing. Also referring 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. Similarly, an annealing treatment, or an annealing treatment and a cooling treatment may be further provided as other steps downstream in the conveying direction of the above-mentioned predetermined looper equipment and prior to the pickling treatment (upstream of the pickling treatment).

[0047] Furthermore, a shearing device (not shown) and a welding device (not shown) may be further provided as other devices upstream in the conveying direction of the above-mentioned predetermined looper equipment. A preferred hot-rolled strip pickling equipment includes, in order from the upstream 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, shearing and welding may be further performed as other processes upstream in the conveying direction of the above-mentioned predetermined looper equipment. A preferred hot-rolled strip pickling method includes, in order from the upstream in the conveying direction, shearing, welding, storage and transport of the steel sheet by the above-mentioned looper equipment, annealing, cooling, and pickling. As described above, steel sheets tend to meander at welded locations. However, welding via the predetermined looper equipment allows for better continuous processing with a higher yield.

[0048] Furthermore, a cold rolling apparatus (not shown) may be provided as another apparatus further downstream in the conveying direction than the above-described pickling apparatus. Similarly, a cold rolling process may be performed as another process further downstream in the conveying direction than the above-described pickling process. As described above, high-speed fracture of the hot-rolled sheet during the cold rolling process due to guide flaws causes serious damage. However, if the hot-rolled sheet is transported to the cold rolling process via a predetermined looper facility, continuous processing can be performed with an even higher yield and in a better 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 be made using the configuration (device) of a known hot-rolled strip pickling equipment and a conventional method of pickling a hot-rolled strip.

[0050] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to these examples. (Example 1) As illustrated in FIG. 9 , in a looper facility 1, the installation interval S of the vertical rolls 7 in the longitudinal direction was variously changed, and a hot-rolled sheet for manufacturing an electromagnetic steel sheet, i.e., a steel sheet 2 having a thickness of 2 mm and a length of 900 m, was transported. The material of the vertical rolls 7 used was chrome steel (C: 1.0%, Si: 0.2%, Mn: 0.3%, P: 0.02%, S: 0.02%, Cr: 1.4%, the balance being Fe and unavoidable impurities). The vertical rolls 7 were cylindrical, with a diameter of 110 mm and a height of 230 mm. The vertical rolls 7 were supported by bearings 71 fixed to the floor surface, and as shown in FIG. 7A , both longitudinal sides and a back side (the side in the width direction that does not face the steel sheet) were rotatably supported by a frame 5. In this embodiment, the vertical roll 7 was not provided with a guard.

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

[0052] The distance D between the steel sheet 2 and the pedestal 5 was set to 156 mm, and similarly, the distance D1 between the steel sheet 2 and the pedestal leg 51 was set to 156 mm, and the distance d between the vertical rolls 7 and the steel sheet 2 was set to 141 mm. Therefore, the lengths (D-d) and (D1-d) of the vertical rolls 7 entering the inside of the conveying region were both 15 mm. The width of the conveying region was 1.6 m, and the maximum width of the steel sheet was 1.3 m. Referring also to FIG. 7A, the downward separation distance d2 of the vertical rolls 7 from the looper parker 6 was set to 100 mm. The upward separation distance d3 of the vertical rolls 7 from the pedestal 5 was set to 30 mm.

[0053] Although not shown in Figure 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 that are arranged at one end in the longitudinal direction; and two looper parkers that are arranged at the other end in the longitudinal direction and that can move along the frame 5 to adjust the amount of steel plate 2 that is stored.

[0054] As shown in Figure 9, the vertical rolls 7, paired in the width direction of the steel sheet 2, were installed facing each other without any longitudinal misalignment relative to the width direction. The vertical rolls were installed in a frame section with 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 Figure 9, for convenience, the installation intervals S of 2.5 m, 5.0 m, 7.5 m, and 10 m are shown arranged on a single line, starting from the left side of the figure. However, in reality, the installation intervals S of 2.5 m (60 pairs in total), 5.0 m (30 pairs in total), 7.5 m (20 pairs in total), and 10 m (15 pairs in total) were arranged on different lines, and one roll of the steel sheet 2 of the above length was transported at each of these installation intervals. For comparison, the case before the installation of the vertical rolls, i.e., the case without the vertical rolls, was also examined. Note that other conditions, such as the transport speed, were conventional.

[0055] The hot-rolled sheet was transported through a looper facility and wound into a coil, and the side surface of each coil was visually inspected along its entire length. If even one guide defect was found, it was determined that a defect had occurred. The same experiment was then conducted for 3,000 coils, and 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 × 100. The results are shown in Table 1.

[0056]

[0057] As shown in Table 1, it was confirmed that providing predetermined vertical rolls in the looper equipment had an effect of reducing the defect occurrence rate of steel sheets. Furthermore, by adjusting the installation interval S of the vertical rolls, it was possible to reduce the defect occurrence rate by more than 40%, and even more than 50%, compared to the defect occurrence 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 60 pairs of installed vertical rolls. The defect occurrence rate of the hot-rolled sheet was determined in the same manner as in Experiment 1 except for the above. Here, the guard was in the form of a plate constituting the side surface of a square pillar as exemplified in Figure 7, with dimensions of 100 mm in the height in the thickness direction of the steel sheet and 200 mm in the 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 at a distance of at least 10 mm from the vertical roll so as not to interfere with the rotation of the vertical roll, and was supported by the wall surface of the frame.

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

[0060] (Example 3) Since the guards in Example 2 were effective in preventing further guide defects on the steel sheet, guarded vertical rolls were used, in which the same guards as in Example 2 were provided on the vertical rolls. Further, similar to Example 1, the guards were installed at intervals S of 2.5 m, 5.0 m, 7.5 m, and 10 m, respectively. Then, 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]

[0062] As shown in Table 2, it was confirmed that the defect occurrence rate of the steel sheet could be further reduced by further providing predetermined guards 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%, further more than 50%, and further 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 2.5 m (60 pairs in total). The vertical rolls had a diameter of 110 mm and a height of 170 mm. The hot-rolled sheet was supplied to a pickling device via a looper system, and the hot-rolled sheet was subjected to pickling treatment. The defect occurrence rate of the hot-rolled sheet was determined in the same manner as in Experiment 1, except for the above. As a result, the defect occurrence rate of the hot-rolled sheet after pickling was reduced from 0.52% before the installation of the vertical rolls to 0.24%. Thus, even when vertical rolls of different heights were installed without attaching guards to the vertical rolls, the effect of reducing the defect occurrence rate was confirmed. Furthermore, the effect of reducing the defect occurrence rate was confirmed even for the hot-rolled sheet after pickling.

[0064] REFERENCE SIGNS LIST 1 Looper equipment 10 Hot-rolled sheet pickling equipment 11 Annealing furnace (annealing equipment) 12 Cooling zone (cooling equipment) 13 Pickling equipment 2 Steel sheet (hot-rolled sheet) 3 Transport roll 4 Fixed roll 5 Frame 51 Frame leg 6 Looper parker (looper parker roll) 7 Vertical roll 71 Bearing 72 Guard D Distance between steel sheet and frame D1 Distance between steel sheet and frame leg d Distance between steel sheet and vertical roll d2 Distance between looper parker and vertical roll d3 Distance between support member (frame) and vertical roll S Installation interval of vertical roll

Claims

1. A looper equipment capable of transporting a steel plate in a longitudinal direction while storing it, comprising: a plurality of transport rolls arranged at intervals in the longitudinal direction so that their rotating shafts extend in the width direction of the steel plate and support one side of the steel plate; at least one fixed roll arranged at one end in the longitudinal direction; stands arranged on both sides in the width direction of the steel plate and extending in the longitudinal direction; and at least one looper parker arranged at the other end in the longitudinal direction and capable of adjusting the amount of steel plate stored by moving along the stand, characterized in that the looper equipment further comprises one or more pairs of vertical rolls arranged in positions that sandwich the steel plate in the width direction and at a distance from the steel plate that is shorter than the distance between the steel plate and the stand, and whose rotating shafts extend in the thickness direction of the steel plate and are rotatable in the transport direction of the steel plate.

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

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

5. A hot-rolled sheet pickling facility, wherein the steel sheet is a hot-rolled sheet for use in electromagnetic steel sheets, and further comprising a pickling device capable of pickling the hot-rolled sheet, located downstream in the conveying direction of the looper facility described in any one of claims 1 to 4, and wherein the hot-rolled sheet is configured so that it can be supplied to the pickling device via the looper facility.

6. A method for pickling a hot-rolled sheet, the method comprising the steps of: supplying the hot-rolled sheet, via a looper facility according to any one of claims 1 to 4, to a pickling device provided downstream in the conveying direction of the looper facility, the hot-rolled sheet being subjected to a pickling treatment.

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