Edge crack detection device, rolling equipment and edge crack detection method

Abstract

The edge crack detection device is used to detect edge cracks of a metal plate to be carried. Among them, the edge crack detection device is provided with a detection unit, and the detection unit includes a plurality of elements arranged along the plate width direction of the metal plate. Each of the plurality of elements is configured to be able to detect whether there is the metal plate at the position in the plate width direction of the element. The edge crack detection device includes: a plate end position determination unit configured to determine the plate end position of the metal plate in the plate width direction based on the detection results of a plurality of first elements among the plurality of elements, and the plurality of first elements are located in a first area in the plate width direction; and an edge crack detection unit configured to detect the edge crack of the metal plate based on the detection results of a plurality of second elements among the plurality of elements, and the plurality of second elements are selected based on the plate end position and are located in a second area narrower than the first area in the plate width direction.

Description

Technical Field

[0001] The present invention relates to an edge crack detection device, a rolling equipment, and an edge crack detection method. Background Art

[0002] In the manufacturing process of a metal plate, edge cracks sometimes occur at the end portions in the plate width direction of the metal plate. If the edge cracks expand, there is a possibility that the plate breaks, so it is important to appropriately detect the edge cracks.

[0003] Patent Document 1 discloses that an edge profiler provided on the output side of a rolling process production line is used to detect an edge crack of a steel plate based on a sharp decrease in the plate thickness in the length direction of the steel plate at the plate end. The edge profiler described in Patent Document 1 includes an X-ray generator and an X-ray detector provided opposite to each other at the plate end. The X-ray detector includes a plurality of sensors arranged in the plate width direction, and measures the plate thickness distribution by detecting the X-rays generated by the X-ray generator and attenuated by the steel plate.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent Laid-Open No. 9-89809 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] However, in the case of detecting an edge crack of a metal plate transported in a rolling production line or the like using a plurality of sensors (elements) arranged in the plate width direction, it is necessary for a computer to receive and process a large amount of detection signals continuously sent from the plurality of sensors at short time intervals. Therefore, in order to appropriately detect a small edge of a metal plate transported at high speed, it is desired to efficiently detect the edge crack.

[0009] In view of the above circumstances, an object of at least one embodiment of the present invention is to provide an edge crack detection device, a rolling equipment, and an edge crack detection method capable of efficiently detecting an edge crack of a metal plate.

[0010] Means for Solving the Problems

[0011] An edge crack detection device according to at least one embodiment of the present invention is used to detect an edge crack of a transported metal plate, wherein

[0012] the edge crack detection device includes a detection unit, and the detection unit includes a plurality of elements arranged along the plate width direction of the metal plate,

[0013] Each of the plurality of elements is configured to be able to detect the presence or absence of the metal plate at a position in the plate width direction of the element.

[0014] The edge crack detection device includes:

[0015] A plate end position determination unit configured to determine the plate end position of the metal plate in the plate width direction based on the detection results of a plurality of first elements among the plurality of elements, the plurality of first elements being located in a first region in the plate width direction; and

[0016] An edge crack detection unit configured to detect an edge crack of the metal plate based on the detection results of a plurality of second elements among the plurality of elements, the plurality of second elements being selected based on the plate end position and being located in a second region narrower than the first region in the plate width direction.

[0017] In addition, a rolling device according to at least one embodiment of the present invention includes:

[0018] A rolling device for rolling a metal plate; and

[0019] The above-mentioned edge crack detection device configured to detect an edge crack at the end of the plate width direction of the metal plate during rolling of the rolling device.

[0020] In addition, an edge crack detection method according to at least one embodiment of the present invention uses a detection unit including a plurality of elements arranged along the plate width direction of the metal plate to detect an edge crack of the transported metal plate, wherein

[0021] Each of the plurality of elements is configured to be able to detect the presence or absence of the metal plate at a position in the plate width direction of the element.

[0022] The edge crack detection method includes the following steps:

[0023] Based on the detection results of a plurality of first elements located in a first region in the plate width direction among the plurality of elements, determine the plate end position of the metal plate in the plate width direction;

[0024] Based on the determined plate end position, select a plurality of second elements located in a second region narrower than the first region in the plate width direction from the plurality of elements; and

[0025] Detect an edge crack of the metal plate based on the detection results of the selected plurality of second elements.

[0026] Advantages of the Invention

[0027] According to at least one embodiment of the present invention, there are provided an edge crack detection device, a rolling equipment, and an edge crack detection method that can efficiently detect edge cracks of a metal plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic structural diagram of a rolling equipment according to an embodiment.

[0029] Figure 2 is a schematic structural diagram of an edge crack detection device according to an embodiment.

[0030] Figure 3 is a schematic structural diagram of an edge crack detection device according to an embodiment.

[0031] Figure 4 is a flowchart showing the process of edge crack detection according to an embodiment.

[0032] Figure 5 is a diagram schematically showing edge cracks generated in a metal plate.

[0033] Figure 6 is a diagram for explaining the edge crack detection process according to an embodiment.

[0034] Figure 7 is to Figure 6 a diagram showing an enlarged view of the plate end of the metal plate in the schematic diagram.

[0035] Figure 8 is a schematic structural diagram of an edge crack detection device according to an embodiment.

[0036] Figure 9 is a schematic structural diagram of an edge crack detection device according to an embodiment.

[0037] Figure 10 is a flowchart showing an example of the determination process based on the first determination unit.

[0038] Figure 11 is a schematic structural diagram of an edge crack detection device according to an embodiment.

[0039] Figure 12 is a schematic structural diagram of an edge crack detection device according to an embodiment.

[0040] Figure 13 is a flowchart showing an example of the determination process based on the second determination unit. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0041] Hereinafter, several embodiments of the present invention will be described with reference to the accompanying drawings. Among them, the dimensions, materials, shapes, and relative configurations of the components described in the embodiments or shown in the drawings are not intended to limit the scope of the present invention thereto, but are merely illustrative examples.

[0042] (Structure of rolling equipment)

[0043] Hereinafter, as an example of the application object of the edge crack detection device of several embodiments, a rolling equipment for rolling a metal plate will be described. However, the edge crack detection device of several embodiments can also be applied to a metal plate processing device other than the rolling equipment.

[0044] Figure 1 is a schematic structural diagram of a rolling equipment to which the edge crack detection device of several embodiments is applied. As shown in Figure 1 shown, the rolling equipment 1 includes: a rolling device 2 configured to roll a metal plate S, and an edge crack detection device 100 for detecting an edge crack of the metal plate S.

[0045] The rolling device 2 includes at least one rolling stand 10 for rolling the metal plate S. In the Figure 1 illustrated embodiment shown, the rolling device 2 includes one rolling stand 10. In other embodiments, the rolling device 2 may also include two or more rolling stands 10.

[0046] The rolling device 2 includes: an uncoiler 4 for unwinding a coil of the metal plate S toward the rolling stand 10, and a winder 14 for winding the metal plate S from the rolling stand 10. In addition, an input side pinch roll 6 and an output side pinch roll 12 for guiding the metal plate S may be respectively provided between the rolling stand 10 and the uncoiler 4, and between the rolling stand 10 and the winder 14.

[0047] Figure 1 The rolling stand 10 shown includes: a pair of rolling rolls (work rolls) 15, 16 provided so as to sandwich the metal plate S as a rolling material, and a pair of intermediate rolls 17, 18 and a pair of backup rolls 19, 20 respectively sandwiching the pair of rolling rolls 15, 16 and provided on the side opposite to the metal plate S. The intermediate rolls 17, 18 and the backup rolls 19, 20 are configured to support the rolling rolls 15, 16. In addition, the rolling stand 10 is provided with a rolling-down device (not shown) for applying a load to the pair of rolling rolls 15, 16 to press down the metal plate S.

[0048] A motor (not shown) is connected to the rolling rolls 15 and 16 via a main shaft (not shown) or the like, and the rolling rolls 15 and 16 are rotated by the motor. When rolling the metal plate S, while pressing down the metal plate S with a pressing device, the rolling rolls 15 and 16 are rotated by the motor, so that a frictional force is generated between the rolling rolls 15 and 16 and the metal plate S, and the metal plate S is conveyed to the output side of the rolling rolls 15 and 16 by using this frictional force.

[0049] (Structure of Edge Crack Detection Device)

[0050] Figure 2 and Figure 3 is a schematic structural diagram of an edge crack detection device according to an embodiment.

[0051] As Figures 1 to 3 shown, the edge crack detection device 100 includes: a detection unit 30 provided near the end in the plate width direction of the conveyed metal plate S; and a processing unit 50 for processing signals from the detection unit 30.

[0052] The processing unit 50 includes: a plate end position determination unit 52 for determining the plate end position in the plate width direction of the metal plate S based on the signal from the detection unit 30; and an edge crack detection unit 54 for detecting an edge crack at the end in the plate width direction of the metal plate S (hereinafter also simply referred to as the end) based on the signal from the detection unit 30.

[0053] The processing unit 50 includes a computer having a processor (such as a CPU), a storage device (storage device, RAM, etc.), an auxiliary storage unit, an interface, and the like. The processing unit 50 receives a detection signal from the detection unit 30 via the interface. The processor is configured to process the signal received as described above. In addition, the processor is configured to process a program expanded in the storage device. Thus, the functions of the above-described respective functional units (the plate end position determination unit 52 and the edge crack detection unit 54) are realized.

[0054] The processing content in the processing unit 50 is installed as a program executed by the processor. The program can also be stored in the auxiliary storage unit. When the program is executed, these programs are expanded in the storage device. The processor reads the program from the storage device and executes the commands included in the program.

[0055] As Figure 3 shown, the detection unit 30 includes a plurality of elements 36 arranged along the plate width direction of the metal plate S. The plurality of elements 36 are each configured to be able to detect whether there is a metal plate S at the position of the element 36 in the plate width direction. A signal indicating the detection result of whether there is a metal plate S is transmitted to the processing unit 50.

[0056] In several embodiments, the detection unit 30 is configured to detect edge cracks using radiation (such as X-rays). In Figure 3In the illustrated exemplary embodiment, the detection unit 30 includes: a radiation light-receiving unit 34 including a plurality of elements 36, and a radiation generating unit 32 disposed on the side opposite to the radiation light-receiving unit 34 with a metal plate S interposed therebetween. The radiation generating unit 32 is configured to generate radiation 101 (such as X-rays) toward the plurality of elements 36 of the radiation light-receiving unit 34.

[0057] In one embodiment, the plurality of elements 36 are semiconductor elements that output a signal when receiving radiation 101. Each of the plurality of elements 36 is configured to detect that the metal plate S does not exist at the position in the plate width direction of the element 36 when receiving radiation 101, and to detect that the metal plate S exists at the position in the plate width direction of the element 36 when not receiving radiation 101.

[0058] That is, in the region where the metal plate S exists in the plate width direction, the radiation 101 from the radiation generating unit 32 is blocked by the metal plate S. Therefore, each of the elements 36 located in this region does not receive the radiation 101, and thus does not output a signal indicating that the radiation 101 has been received. On the other hand, in the region where the metal plate S does not exist in the plate width direction, the radiation 101 from the radiation generating unit 32 is not blocked by the metal plate S. Therefore, each of the elements 36 located in this region receives the radiation 101 and outputs a signal indicating that the radiation 101 has been received.

[0059] The above semiconductor element may also be a CdTe (cadmium telluride) - based semiconductor element. Since the CdTe - based semiconductor element has high resolution, it is easy to appropriately detect the plate end position and edge crack of the metal plate S being transported at high speed.

[0060] The arrangement pitch of the plurality of elements 36 in the plate width direction is not particularly limited, and for example, it may be 0.05 mm or more and 1 mm or less.

[0061] (Processing flow for edge crack detection)

[0062] Hereinafter, the processing flow (edge crack detection method) of edge crack detection of the edge crack detection device 100 based on several embodiments will be described. Figure 4 It is a flowchart showing the processing flow of edge crack detection of the edge crack detection device 100 based on several embodiments.

[0063] As Figure 4 shown, in one embodiment, first, based on the detection results of each of the plurality of first elements 36A located in the first region R1 (refer to Figure 3 ) in the plate width direction among the plurality of elements 36, the position of the plate end E of the metal plate S in the plate width direction is determined (S2).

[0064] Regarding step S2, for Figure 3The following describes the shown situation. In Figure 3 In the shown example, among the multiple first elements 36A, the first element 36A located at the position of the first element 36A' and on the inner side (center line side of the metal plate S) in the plate width direction relative to the first element 36A' detects the presence of the metal plate S at the position of each first element 36A. In addition, among the multiple first elements 36A, the first element 36A located at the position on the outer side (opposite side to the center line of the metal plate S) in the plate width direction relative to the first element 36A' detects the absence of the metal plate S at the position of each first element 36A. Therefore, in this case, it is determined that the plate end E is located at the position of the first element 36A' in the plate width direction.

[0065] The length of the first region R1 in the plate width direction described above is set such that even when the metal plate S meanders slightly during transportation, the plate end E is included within the range of the first region R1. The length of the first region R1 in the plate width direction can be, for example, 1 / 4 or more of the plate width of the metal plate S.

[0066] Next, the edge crack detection unit 54 selects, based on the position of the plate end E determined in step S2, multiple second elements 36B (S4) for detecting edge cracks from among the multiple elements 36 in the subsequent step S6. The multiple second elements 36B are located within a second region R2 that is narrower than the first region R1 in the plate width direction.

[0067] The above-mentioned second region R2 can be a region including the position of the plate end E (i.e., the position of the first element 36A'). In one embodiment, for example, as Figure 3 shown, the second region R2 can be a region between the position of the plate end E and the position offset inward in the plate width direction from this position. Alternatively, in one embodiment, the second region R2 can also be a region between the position offset inward in the plate width direction from the position of the plate end E and the position offset outward in the plate width direction from the position of the plate end E.

[0068] In addition, the edge crack detection unit 54 only needs to select multiple second elements for detecting edge cracks based on the position of the plate end E, and can also be set to always detect the element closest to the innermost side in the plate width direction as the element at the inner end in the plate width direction belonging to the second region R2. In this case, the first region is also narrower than the second region.

[0069] It should be noted that in Figure 3 the shown example, each of the elements 36 selected as the second element 36B among the multiple elements 36 also functions as the first element 36A. That is, in several embodiments, each of the multiple elements 36 can be configured to be able to function as both the first element 36A and the second element 36B.

[0070] The length of the second region R2 in the plate width direction described above can also be set based on the length of the edge crack that can be generated in the metal plate S in the plate width direction. For example, it can also be more than twice the maximum length of the edge crack expected to be generated in the metal plate S in the plate width direction.

[0071] In addition, the number of the plurality of first elements 36A can also be more than 20 times and less than 200 times the number of the plurality of second elements 36B.

[0072] Next, the edge crack detection unit 54 detects the edge crack of the metal plate S (S6) based on the detection results of the plurality of second elements 36B selected in step S4.

[0073] Here, Figure 5 is a diagram schematically showing the edge crack ( Figure 5 the shaded part in) generated in the metal plate S. As Figure 5 shown, the edge crack 90 is a defect generated at the end of the metal plate S in the plate width direction. The edge crack 90 generally has a shape that depresses from the plate end E of the metal plate S toward the inside in the plate width direction. It should be noted that, Figure 5 the edge crack 90 shown in has a length of W in the plate width direction of the metal plate S and a length of L in the length direction of the metal plate S.

[0074] When there is an edge crack 90 (the defective part of the metal plate S) in the metal plate S, the second elements 36B at the positions where the edge crack 90 exists in the plate width direction respectively detect that there is no metal plate at that position. In addition, the second elements 36B at the positions where the edge crack 90 does not exist in the plate width direction respectively detect that there is a metal plate S at that position. Therefore, based on the detection results of the plurality of second elements 36B, it is possible to detect whether there is an edge crack in the metal plate S.

[0075] According to the above-described embodiment, it is possible to detect an edge crack using a small number of second elements 36B selected based on the position of the plate end E determined according to the detection results of the plurality of first elements 36A. Therefore, compared with the case of detecting an edge crack using a large number of elements, etc., the computational processing load can be reduced, and the edge crack can be detected efficiently. In addition, in the above-described embodiment, since a small number of second elements 36B are used to detect the edge crack, compared with the case of using a large number of elements, it is easier to detect the edge crack in a short cycle. Therefore, it is possible to appropriately detect a small edge crack of the metal plate S being conveyed at high speed.

[0076] In several embodiments, in step S2, the board end position determination unit 52 obtains the detection results of the respective plurality of first elements 36A every first cycle time T1, and determines the position of the board end E based on the detection results. Then, in step S6, the edge crack detection unit 54 is configured to obtain the detection results of the respective plurality of second elements 36B every second cycle time T2, and the second cycle time T2 is shorter than the first cycle time T1.

[0077] Figure 6 FIG. is a diagram for explaining the edge crack detection process of an embodiment, and is a schematic diagram showing the detection positions of the respective plurality of elements 36 in the width direction and the length direction of the metal plate S moving in the traveling direction in accordance with the traveling of the metal plate S. In Figure 6 FIG., the detection positions of the plurality of first elements 36A are indicated by a dashed line 102, and the detection positions of the plurality of second elements 36B are indicated by a dashed line 104. Here, it is assumed that the metal plate S is conveyed at a constant speed V. It should be noted that during the first cycle time T1, the metal plate S travels a distance L1 (= V × T1), and during the second cycle time T2, the metal plate S travels a distance L2 (= V × T2).

[0078] It should be noted that in Figure 6 FIG., the plurality of first elements 36A sequentially detect whether there is a metal plate S at the position in the width direction of the first element 36A starting from the first element 36A located on the outermost side in the width direction. In addition, the plurality of second elements 36B sequentially detect whether there is a metal plate S at the position in the width direction of the second element 36B starting from the second element 36B located on the outermost side in the width direction. In addition, in Figure 6 FIG., the second region R2 is a region on the inner side in the width direction starting from the position (P1, P2, etc.) of the board end E determined by the plurality of first elements 36A.

[0079] When the detection results of the respective plurality of first elements 36A are obtained once each (that is, the states of the respective plurality of first elements 36A are read in) every first cycle time T1, as Figure 6 shown, during the first cycle time T1, the metal plate S travels a distance L1, so within the range of the length L1 in the length direction of the metal plate S, it is detected by the plurality of first elements 36A whether there is a metal plate S at each position in the first region R1 in the width direction. Within this length L1 range, usually the position of one board end is detected (P1, P2 in the figure).

[0080] In addition, when the detection results of the respective plurality of second elements 36B are obtained once each (that is, the states of the respective plurality of second elements 36B are read in) every second cycle time T2, as Figure 6As shown, during the second cycle time T2, the metal plate S travels a distance L2. Therefore, within the range of the length L2 in the length direction of the metal plate S, the presence or absence of the metal plate S at each position within the second region R2 in the plate width direction is detected by a plurality of second elements 36B.

[0081] The change in the position of the plate end E of the metal plate S during conveyance is relatively slow compared to the conveyance speed of the metal plate S. For example, in the case of a typical rolling apparatus, there are cases where the plate end position changes by several millimeters while the metal plate S travels several meters. In this case, since the position of the plate end E gradually changes, the change in the position of the plate end E can be detected even if the detection cycle is not shortened very much. On the other hand, the size of the edge crack of the metal plate S is extremely small compared to the conveyance speed of the metal plate S. For example, with respect to a typical conveyance speed of a rolling apparatus of several hundred mpm (or several thousand mm / s), the length of the edge crack in the length direction of the metal plate S is on the order of 0.5 to several millimeters. Therefore, in order to detect edge cracks without omission, it is necessary to shorten the detection cycle to a certain extent.

[0082] Regarding this point, according to the above-described embodiment, the detection results of the respective first elements 36A are obtained every relatively long first cycle time T1, so that an increase in the computational processing load for determining the position of the plate end E can be suppressed, and the detection results of the respective second elements 36B are obtained every relatively short second cycle time T2, so that smaller edge cracks of the metal plate S conveyed at high speed can be detected more reliably.

[0083] In several embodiments, the second cycle time T2 is 1 / 10 or less of the first cycle time T1. That is, Figure 6 the travel distance L2 of the metal plate S during the shown second cycle time T2 is 1 / 10 or less of the travel distance L1 of the metal plate S during the first cycle time T1.

[0084] In this case, since the detection results of the respective first elements 36A are obtained every relatively long first cycle time T1 that is 10 times or more longer than the second cycle time T2, an increase in the computational processing load for determining the position of the plate end E can be suppressed, and since the detection results of the respective second elements 36B are obtained every relatively short second cycle time T2 that is 1 / 10 or less of the first cycle time T1, smaller edge cracks of the metal plate S conveyed at high speed can be detected more reliably.

[0085] In several embodiments, in step S2, the plate end position determination unit 52 is configured to sequentially read the states of a plurality of first elements 36A along the plate width direction every first cycle time T1, thereby obtaining the detection results of the plurality of first elements 36A in the first cycle time T1. It should be noted that when sequentially reading the states of the plurality of first elements 36A along the plate width direction from the outside to the inside in the plate width direction, the detection position based on the detection of the presence or absence of the metal plate S by the plurality of first elements 36A is the position shown by the dashed line 102 in Figure 6 as shown.

[0086] According to the above-described embodiment, the states of the plurality of first elements 36A are sequentially read along the plate width direction every first cycle time T1 to obtain the detection results of the plurality of first elements 36A. Therefore, the position of the plate end E of the metal plate S can be determined with a relatively simple structure. For example, the plate end position determination unit 52 can be implemented as a program with a relatively simple structure.

[0087] In Figure 6 the detection speed shown by the dashed line 104 is greater than the detection speed shown by the dashed line 102. Thus, the greater the detection speed, the more preferable it is for the detection of edge cracks. However, it is not limited thereto. The detection speed of the dashed line 104 can also be the same as the detection speed of the dashed line 102, or can be less than the detection speed of the dashed line 102. Here, the detection speed refers to the moving distance (the number of detected elements) / sampling time.

[0088] In several embodiments, in step S6, the edge crack detection unit 54 is configured to sequentially read the states of a plurality of second elements 36B along the plate width direction every second cycle time T2, thereby obtaining the detection results of the plurality of second elements 36B in the second cycle time T2. It should be noted that when sequentially reading the states of the plurality of second elements 36B along the plate width direction from the outside to the inside in the plate width direction, the detection position based on the detection of the presence or absence of the metal plate S by the plurality of second elements 36B is the position shown by the dashed line 104 in Figure 6 as shown.

[0089] According to the above-described embodiment, the states of the plurality of second elements 36B are sequentially read along the plate width direction every second cycle time T2 to obtain the detection results of the plurality of second elements 36B. Therefore, the edge cracks of the metal plate S can be detected with a relatively simple structure. For example, the edge crack detection unit 54 can be implemented as a program with a relatively simple structure.

[0090] Figure 7 is to Figure 6A diagram showing an enlarged view of the end portion of the metal plate S in the schematic diagram. Each point (black circle and white circle) in the figure represents the detection result of each second element 36B. The black circle indicates that no metal plate S is detected at the position in the plate width direction of the second element 36B, and the white circle indicates that a metal plate S is detected at the position in the plate width direction of the second element 36B.

[0091] In several embodiments, in step S6, the edge crack detection unit 54 is configured to detect an edge crack based on the number of second elements 36B among the plurality of second elements 36B that detect that no metal plate S exists at the position in the plate width direction of the second element 36B (i.e., Figure 7 the number of black circles in the figure).

[0092] It should be noted that the edge crack detection unit 54 may also obtain the number of second elements 36B among the plurality of second elements 36B that detect that no metal plate S exists at the position in the plate width direction of the second element 36B every second cycle time T2, and detect an edge crack based on this number every second cycle time T2.

[0093] When there is an edge crack in the metal plate S, the second element 36B corresponding to the position of the edge crack in the plate width direction detects that no metal plate S exists at that position, and other second elements detect that a metal plate S exists at the position corresponding to the second element 36B. According to the above embodiments, based on the number of second elements 36B among the plurality of second elements 36B that detect that no metal plate S exists at the position in the plate width direction of the second element 36B, the edge crack of the metal plate S can be appropriately detected.

[0094] In several embodiments, in step S6, the edge crack detection unit 54 is configured to determine that there is an edge crack in the metal plate S when a specified number or more of continuously arranged second elements 36B among the plurality of second elements 36B each detect that no metal plate S exists.

[0095] For example, when the total number of second elements is M, it may be determined that there is an edge crack in the metal plate S when L or more continuously arranged second elements 36B detect that no metal plate S exists.

[0096] More specifically, for example, as Figure 7 shown, when the total number of second elements 36B is 10, it may be determined that there is an edge crack in the metal plate S when 5 or more continuously arranged second elements 36B detect that no metal plate S exists. In Figure 7In the example shown, in each of the cycles C1 to C4, each of which is the second cycle time T2, the numbers of the second elements 36B in which no metal plate S is detected continuously are 1, 3, 6, and 4, respectively. That is, in cycle C3, in the detection of 5 or more (specifically, 6) consecutive second elements 36B, no metal plate S is detected. Therefore, it can be determined that an edge crack exists in the metal plate S at the position in the longitudinal direction corresponding to cycle C3.

[0097] In several embodiments, in step S6, the edge crack detection unit 54 is configured to determine that an edge crack exists in the metal plate S when the ratio N / M of the number N of the second elements 36B in which no metal plate S is detected to the number (total number) M of the plurality of second elements 36B is equal to or greater than a specified value.

[0098] For example, it may be determined that an edge crack exists in the metal plate S when the ratio N / M is 1 / 2 or more. For example, in Figure 7 the example shown, the total number (M) of the second elements 36B is 10. In addition, in each of the cycles C1 to C4, each of which is the second cycle time T2, the numbers (N) of the second elements 36B in which no metal plate S is detected are 1, 6, 6, and 4, respectively. Therefore, in cycles C2 and C3, N / M is 1 / 2 or more. Therefore, it can be determined that an edge crack exists in the metal plate S at the positions in the longitudinal direction corresponding to cycles C2 and C3.

[0099] Figure 8 and Figure 9 are schematic structural diagrams of an edge crack detection device 100 according to an embodiment. It should be noted that Figure 8 is a view of the vicinity of the rolling stand 10 in the rolling equipment 1 in a top view.

[0100] As Figure 8 shown, in one embodiment, on the first end E1 side in the plate width direction of the metal plate S, a plurality of detection units 30 (an upstream detection unit 30A and a downstream detection unit 30B) are provided at different positions in the traveling direction of the metal plate S. In addition, as Figure 9 shown, the processing unit 50 includes a plurality of plate end position determination units 52 and a plurality of edge crack detection units 54 provided corresponding to each of the plurality of detection units 30, respectively. Specifically, an upstream plate end position determination unit 52A and an upstream edge crack detection unit 54A are provided corresponding to the upstream detection unit 30A, and a downstream plate end position determination unit 52B and a downstream edge crack detection unit 54B are provided corresponding to the downstream detection unit 30B.

[0101] The upstream-side edge crack detection unit 54A is configured to determine the possibility of the existence of an edge crack in the metal plate S based on whether the second elements 36B among the plurality of second elements 36B of the upstream-side detection unit 30A, which are located inside the position of the first end E1 determined by the upstream-side plate end position determination unit 52A, detect the absence of the metal plate S. The downstream-side edge crack detection unit 54B is configured to determine the possibility of the existence of an edge crack in the metal plate S based on whether the second elements 36B among the plurality of second elements 36B of the downstream-side detection unit 30B, which are located inside the position of the first end E1 determined by the downstream-side plate end position determination unit 52B, detect the absence of the metal plate S.

[0102] The processing unit 50 includes a first determination unit 56, which is configured to determine whether there is an edge crack on the metal plate S based on the determination results of the upstream-side edge crack detection unit 54A and the downstream-side edge crack detection unit 54B. The first determination unit 56 is configured to determine that there is an edge crack on the metal plate S when only one of the upstream-side edge crack detection unit 54A and the downstream-side edge crack detection unit 54B determines the possibility of the existence of an edge crack at the same time.

[0103] Figure 10 It is a flowchart showing an example of the determination process of the above-mentioned first determination unit 56. First, as described above, the upstream-side edge crack detection unit 54A and the downstream-side edge crack detection unit 54B respectively determine the possibility of the existence of an edge crack in the metal plate S (S102). As a result, the upstream-side edge crack detection unit 54A determines the possibility of the existence of an edge crack in the metal plate S (Yes in S104). In this case, the first determination unit 56 determines whether the downstream-side edge crack detection unit 54B determines the possibility of the existence of an edge crack in the metal plate S at the same time as the determination based on the upstream-side edge crack detection unit 54A in step S104 (S106).

[0104] If the downstream-side edge crack detection unit 54B does not determine the possibility of the existence of an edge crack in the metal plate S at the same time (No in S106), it is determined that there is an edge crack on the metal plate S (S108), and the process ends. On the other hand, if the downstream-side edge crack detection unit 54B determines the possibility of the existence of an edge crack in the metal plate S at the same time (Yes in S106), it is determined that there is a possibility that no edge crack has occurred on the metal plate S (S110), and the process ends.

[0105] Note that when both the upstream edge crack detection unit 54A and the downstream edge crack detection unit 54B determine that there is a possibility of an edge crack at the same time (Yes in S106), the first determination unit 56 may also determine that there is a possibility that the metal plate S has a meandering (vibration in the plate width direction) without generating an edge crack.

[0106] Alternatively, in step S106, when both the upstream edge crack detection unit 54A and the downstream edge crack detection unit 54B determine that there is a possibility of an edge crack of the same size being generated in the plate width direction or the length direction of the metal plate S at the same time, the first determination unit 56 may also determine that there is a possibility that the metal plate S has a meandering (vibration in the plate width direction) without generating an edge crack.

[0107] Note that in the above steps S102 to S110, even if the upstream edge crack detection unit 54A and the downstream edge crack detection unit 54B are swapped, the same explanation holds.

[0108] According to the above embodiment, when only one of the upstream edge crack detection unit 54A and the downstream edge crack detection unit 54B determines that there is a possibility of an edge crack at the same time, it is determined that there is an edge crack on the metal plate S, so that misjudgment regarding the presence or absence of an edge crack can be suppressed. For example, when the metal plate S actually has a meandering, the situation of misjudging it as an edge crack can be suppressed.

[0109] Figure 11 and Figure 12 are schematic structural diagrams of an edge crack detection device 100 according to an embodiment. Note that Figure 11 is a view of the vicinity of the rolling stand 10 in the rolling equipment 1 in a top view.

[0110] As Figure 11 shown, in one embodiment, detection units 30 (a first end side detection unit 30C and a second end side detection unit 30D) are provided on the first end E1 side and the second end E2 side in the plate width direction of the metal plate S, respectively. In addition, as Figure 12 shown, the processing unit 50 includes a plurality of plate end position determination units 52 and a plurality of edge crack detection units 54 provided corresponding to each of the plurality of detection units 30. Specifically, a first end side plate end position determination unit 52C and a first end side edge crack detection unit 54C are provided corresponding to the first end side detection unit 30C, and a second end side plate end position determination unit 52D and a second end side edge crack detection unit 54D are provided corresponding to the second end side detection unit 30D.

[0111] The first end-side edge crack detection unit 54C is configured to determine the possibility of the existence of an edge crack in the metal plate S based on whether the second elements 36B among the plurality of second elements 36B of the first end-side detection unit 30C, which are located at positions closer to the inside than the position of the first end E1 determined by the first end-side plate end position determination unit 52C, detect the absence of the metal plate S. The second end-side edge crack detection unit 54D is configured to determine the possibility of the existence of an edge crack in the metal plate S based on whether the second elements 36B among the plurality of second elements 36B of the second end-side detection unit 30D, which are located at positions closer to the inside than the position of the second end E2 determined by the second end-side plate end position determination unit 52D, detect the absence of the metal plate S.

[0112] The processing unit 50 includes a second determination unit 58, which is configured to determine whether there is an edge crack on the metal plate S based on the determination results of the first end-side edge crack detection unit 54C and the second end-side edge crack detection unit 54D. The second determination unit 58 is configured to determine that there is an edge crack on the metal plate S when, at the same time, the first end-side edge crack detection unit 54C determines that there is a possibility of an edge crack, and among the second elements 36B of the second end-side edge crack detection unit 54D that are located on the outer side of the position of the second end E2 in the plate width direction, the presence of the metal plate S is not detected.

[0113] Figure 13 It is a flowchart showing an example of the determination process of the above-mentioned second determination unit 58. First, as described above, the possibility of the existence of an edge crack in the metal plate S is determined by the first end-side edge crack detection unit 54C and the second end-side edge crack detection unit 54D respectively (S202). As a result, the first end-side edge crack detection unit 54C determines that there is a possibility of an edge crack in the metal plate S (Yes in S204). In this case, the second determination unit 58 determines whether the second element 36B, which is located on the outer side of the position of the second end E2 in the plate width direction of the second end-side edge crack detection unit 54D at the same time as the determination based on the first end-side edge crack detection unit 54C in step S204, detects the presence of the metal plate (S206).

[0114] When the second end-side edge crack detection unit 54D determines at the same time that the second element 36B located outside the position of the second end E2 in the plate width direction does not detect the presence of the metal plate (No in S206), it is determined that there is an edge crack on the metal plate S (S208), and the process ends. On the other hand, when the second end-side edge crack detection unit 54D determines at the same time that the second element 36B located outside the position of the second end E2 in the plate width direction detects the presence of the metal plate (Yes in S206), it is determined that there is a possibility that no edge crack has occurred on the metal plate S (S210), and the process ends.

[0115] It should be noted that at the same time, when the first end-side edge crack detection unit 54C determines that there is a possibility of an edge crack, and the second end-side edge crack detection unit 54D determines that the second element 36B located outside the position of the second end E2 in the plate width direction detects the presence of the metal plate (Yes in S206), the second determination unit 58 may also determine that there is a possibility that meandering (vibration in the plate width direction) has occurred on the metal plate S without an edge crack.

[0116] Alternatively, at the same time in step S206, when both the first end-side edge crack detection unit 54C and the second end-side edge crack detection unit 54D detect that the first end E1 and the second end E2 are offset in the same direction, the second determination unit 58 may also determine that there is a possibility that meandering (vibration in the plate width direction) has occurred on the metal plate S without an edge crack.

[0117] It should be noted that in the above steps S202 to S210, the same explanation holds even if the first end-side edge crack detection unit 54C and the second end-side edge crack detection unit 54D are swapped.

[0118] According to the above-described embodiment, when only one of the first end-side edge crack detection unit 54C and the second end-side edge crack detection unit 54D determines at the same time that there is a possibility of an edge crack, it is determined that there is an edge crack on the metal plate S, so that misjudgment regarding the presence or absence of an edge crack can be suppressed. For example, when meandering actually occurs on the metal plate S, the situation of misjudging it as an edge crack can be suppressed.

[0119] According to the above-described embodiment, at the same moment, when the first end-side edge crack detection unit 54C determines that there is a possibility of an edge crack, and in the second end-side edge crack detection unit 54D, when the second element 36B located outside the position of the second end E2 in the plate width direction does not detect the presence of the metal plate S, it is determined that there is an edge crack on the metal plate S. Therefore, false determination regarding the presence or absence of an edge crack can be suppressed. For example, when the metal plate S actually has a meandering progression, the case of misjudging it as an edge crack can be suppressed.

[0120] Hereinafter, an outline of an edge crack detection device, a rolling facility, and an edge crack detection method for several embodiments will be described.

[0121] (1) An edge crack detection device according to at least one embodiment of the present invention is configured to detect an edge crack of a transported metal plate, wherein

[0122] the edge crack detection device includes a detection unit including a plurality of elements arranged along the plate width direction of the metal plate,

[0123] each of the plurality of elements is configured to be able to detect the presence or absence of the metal plate at a position in the plate width direction of the element,

[0124] the edge crack detection device includes:

[0125] a plate end position determination unit configured to determine a plate end position in the plate width direction of the metal plate based on detection results of a plurality of first elements among the plurality of elements, the plurality of first elements being located in a first region in the plate width direction; and

[0126] an edge crack detection unit configured to detect an edge crack of the metal plate based on detection results of a plurality of second elements among the plurality of elements, the plurality of second elements being selected based on the plate end position and located in a second region narrower than the first region in the plate width direction.

[0127] According to the structure of the above (1), it is possible to detect an edge crack using a small number of elements (second elements fewer than the first elements) selected based on the plate end position determined from the detection results of the plurality of first elements. Therefore, compared with the case of detecting an edge crack using a plurality of first elements, the computational processing load can be reduced, and the edge crack can be detected efficiently. In addition, in the structure of the above (1), since a relatively small number of second elements are used for edge crack detection, compared with the case of using a large number of elements, it is easier to detect an edge crack in a short cycle. Therefore, it is possible to appropriately detect a small edge crack of a metal plate transported at high speed.

[0128] (2) In several embodiments, based on the structure in (1) above,

[0129] The plate end position determination unit is configured to obtain the detection results of each of the plurality of first elements every first cycle time, and determine the plate end position based on the detection results.

[0130] The edge crack detection unit is configured to obtain the detection results of each of the plurality of second elements every second cycle time, and the second cycle time is shorter than the first cycle time.

[0131] The change in the plate end position during the conveyance of the metal plate is relatively slow compared to the conveyance speed of the metal plate. On the other hand, the size of the edge crack is small compared to the conveyance speed of the metal plate. Regarding this point, according to the structure in (2) above, since the detection results of each of the plurality of first elements are obtained every relatively long first cycle time, an increase in the computational processing load for determining the plate end position can be suppressed, and since the detection results of each of the plurality of second elements are obtained every relatively short second cycle time, smaller edge cracks of the metal plate conveyed at high speed can be detected more reliably.

[0132] (3) In several embodiments, based on the structure in (2) above,

[0133] The second cycle time is 1 / 10 or less of the first cycle time.

[0134] According to the structure in (3) above, since the detection results of each of the plurality of first elements are obtained every relatively long first cycle time that is 10 times or more longer than the second cycle time, an increase in the computational processing load for determining the plate end position can be suppressed, and since the detection results of each of the plurality of second elements are obtained every relatively short second cycle time that is 1 / 10 or less of the first cycle time, smaller edge cracks of the metal plate conveyed at high speed can be detected more reliably.

[0135] (4) In several embodiments, based on the structure in (2) or (3) above,

[0136] The plate end position determination unit is configured to sequentially read the states of the plurality of first elements along the plate width direction every first cycle time, thereby obtaining the detection results of the plurality of first elements during the first cycle time.

[0137] According to the structure in (4) above, the detection results of the plurality of first elements are obtained by sequentially reading the states of the plurality of first elements along the plate width direction every first cycle time, so that the plate end position of the metal plate can be determined with a relatively simple structure.

[0138] (5) In several embodiments, based on any of the structures in (2) to (4) above,

[0139] The edge crack detection unit is configured to sequentially read the states of a plurality of the second elements along the plate width direction every second cycle time, thereby obtaining the detection results of the plurality of second elements in the second cycle time.

[0140] According to the structure in (5) above, by sequentially reading the states of a plurality of second elements along the plate width direction every second cycle time to obtain the detection results of the plurality of second elements, it is possible to detect an edge crack of a metal plate with a relatively simple structure.

[0141] (6) In several embodiments, based on any of the structures in (1) to (5) above,

[0142] The edge crack detection unit is configured to detect the edge crack based on the number of the second elements among the plurality of second elements that detect the following situation: there is no metal plate at the position in the plate width direction of the second element.

[0143] When there is an edge crack in the metal plate, the second element corresponding to the position of the edge crack in the plate width direction detects that there is no metal plate at that position, and other second elements detect that there is a metal plate at the position corresponding to the second element. According to the structure in (6) above, based on the number of the second elements among the plurality of second elements that detect that there is no metal plate at the position in the plate width direction of the second element, it is possible to appropriately detect the edge crack of the metal plate.

[0144] (7) In several embodiments, based on the structure in (6) above,

[0145] The edge crack detection unit is configured to determine that there is an edge crack in the metal plate when each of a specified number or more of the second elements arranged continuously among the plurality of second elements detects that there is no metal plate.

[0146] According to the structure in (7) above, based on each of a specified number or more of the second elements arranged continuously among the plurality of second elements detecting that there is no metal plate at the position in the plate width direction corresponding to the second element, it is possible to appropriately detect the edge crack of the metal plate.

[0147] (8) In several embodiments, based on the structure in (6) or (7) above,

[0148] The edge crack detection unit is configured to determine that there is an edge crack in the metal plate when the ratio of the number of the second elements that detect that there is no metal plate to the number of the plurality of second elements is equal to or greater than a specified value.

[0149] According to the structure of (8) above, based on the ratio of the number of second elements that detect the absence of the metal plate to the number of multiple second elements being equal to or greater than a specified value, the edge crack of the metal plate can be appropriately detected.

[0150] (9) In several embodiments, based on any one of the structures of (1) to (8) above,

[0151] The second region is the region between the plate end position and the position offset inward in the plate width direction from the plate end position.

[0152] The edge crack of the metal plate occurs in the inner position range starting from the plate end of the metal plate. According to the structure of (9) above, based on the detection results of multiple second elements in the inner region, that is, the second region, starting from the plate end position, the edge crack of the metal plate can be appropriately detected.

[0153] (10) In several embodiments, based on any one of the structures of (1) to (9) above,

[0154] The edge crack detection unit is configured to determine the possibility of the existence of an edge crack in the metal plate based on whether the second elements among the multiple second elements located at positions closer to the inner side than the plate end position detect the absence of the metal plate.

[0155] The edge crack detection device includes:

[0156] An upstream edge crack detection unit as the edge crack detection unit;

[0157] A downstream edge crack detection unit as the edge crack detection unit, which is provided at a position different from that of the upstream edge crack detection unit in the conveying direction of the metal plate; and

[0158] A first determination unit configured to determine that there is an edge crack in the metal plate when only one of the upstream edge crack detection unit and the downstream edge crack detection unit determines the possibility of the existence of the edge crack at the same time.

[0159] According to the structure of (10) above, when only one of the upstream edge crack detection unit and the downstream edge crack detection unit provided at different positions in the conveying direction of the metal plate determines the possibility of the existence of the edge crack at the same time, it is determined that there is an edge crack in the metal plate, so that false determination regarding the presence or absence of an edge crack can be suppressed.

[0160] (11) In several embodiments, based on any one of the structures of (1) to (8) above,

[0161] The edge crack detection unit is configured to determine the possibility of the existence of an edge crack in the metal plate based on whether the second elements among the plurality of second elements, which are located inside the plate end position, detect the absence of the metal plate.

[0162] The edge crack detection device includes:

[0163] A first end side edge crack detection unit as the edge crack detection unit;

[0164] A second end side edge crack detection unit as the edge crack detection unit, which is disposed on the opposite side of the first end side edge crack detection unit across the metal plate in the plate width direction; and

[0165] A second determination unit, which is configured to determine that there is an edge crack in the metal plate when, at the same time, the first end side edge crack detection unit determines that there is a possibility of the existence of the edge crack, and in the second end side edge crack detection unit, the second element located outside the plate end position in the plate width direction does not detect the existence of the metal plate.

[0166] According to the structure of the above (11), when, at the same time, the first end side edge crack detection unit determines that there is a possibility of the existence of an edge crack, and in the second end side edge crack detection unit, the second element located outside the plate end position in the plate width direction does not detect the existence of the metal plate, it is determined that there is an edge crack in the metal plate, so that misjudgment regarding the presence or absence of an edge crack can be suppressed.

[0167] (12) In several embodiments, based on any one of the structures of the above (1) to (11),

[0168] The detection unit includes:

[0169] A radiation light receiving unit, which includes a plurality of the elements; and

[0170] A radiation generating unit, which is disposed on the opposite side of the radiation light receiving unit across the metal plate and is configured to generate radiation toward the radiation light receiving unit,

[0171] Each of the plurality of elements is configured to detect the absence of the metal plate at the position in the plate width direction of the element when receiving the radiation, and detect the existence of the metal plate at the position in the plate width direction of the element when not receiving the radiation.

[0172] Near a processing device (such as a rolling device) for a metal plate, rolling oil and soot are scattered in large amounts, and there are many cases of harsh environments such as vibration and dimness of the equipment. In this regard, according to the structure of the above (12), since an edge crack sensor that uses radiation to detect edge cracks is used, it is possible to detect edge cracks near the processing device in a harsh environment.

[0173] (13) A rolling equipment according to at least one embodiment of the present invention includes:

[0174] A rolling device for rolling a metal plate; and

[0175] The edge crack detection device according to any one of the above (1) to (12), configured to detect edge cracks at the end portions in the plate width direction of the metal plate during rolling of the rolling device.

[0176] According to the structure of the above (13), it is possible to use a small number of elements (second elements fewer than the first elements) selected based on the plate end position determined according to the detection results of a plurality of first elements to detect edge cracks. Therefore, compared with the case of using a plurality of first elements for edge crack detection, etc., the computational processing load can be reduced, and edge cracks can be detected efficiently. In addition, in the structure of the above (13), since a small number of second elements are used for edge crack detection, compared with the case of using a large number of elements, it is easier to detect edge cracks in a short cycle. Therefore, it is possible to appropriately detect small edge cracks of a metal plate being transported at high speed.

[0177] (14) An edge crack detection method according to at least one embodiment of the present invention uses a detection unit including a plurality of elements arranged along the plate width direction of a metal plate to detect edge cracks of the transported metal plate, wherein

[0178] Each of the plurality of elements is configured to be able to detect whether the metal plate is present at a position in the plate width direction of the element,

[0179] The edge crack detection method includes the following steps:

[0180] Based on the detection results of a plurality of first elements located in a first region in the plate width direction among the plurality of elements, determine the plate end position of the metal plate in the plate width direction;

[0181] Based on the determined plate end position, select a plurality of second elements located in a second region narrower than the first region in the plate width direction from the plurality of elements; and

[0182] Detect edge cracks of the metal plate based on the detection results of the selected plurality of second elements.

[0183] According to the structure of (14) above, it is possible to detect an edge crack using a small number of elements (second elements fewer than the first elements) selected based on the board end position determined from the detection results of a plurality of first elements. Therefore, compared with the case of using a plurality of first elements for edge crack detection, etc., the computational processing load can be reduced, and edge cracks can be detected efficiently. In addition, in the structure of (14) above, since a relatively small number of second elements are used for edge crack detection, compared with the case of using a large number of elements, it is easier to detect edge cracks in a short cycle. Therefore, it is possible to appropriately detect small edge cracks of a metal plate being transported at high speed.

[0184] The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments, and also includes modified forms of the above embodiments and forms obtained by appropriately combining these forms.

[0185] In this specification, expressions indicating relative or absolute configurations such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric", or "coaxial" not only represent such configurations in a strict sense, but also represent states of relative displacement with tolerances or at angles and distances that can achieve the same function.

[0186] For example, expressions indicating equal states of things such as "identical", "equal", and "homogeneous" not only represent strictly equal states, but also represent states with tolerances or differences that can achieve the same function.

[0187] In addition, in this specification, expressions indicating shapes such as a quadrilateral shape and a cylindrical shape not only represent geometrically strict quadrilateral shapes, cylindrical shapes, etc., but also represent shapes including concave and convex portions, chamfered portions, etc. within a range where the same effect can be obtained.

[0188] In addition, in this specification, expressions such as "comprising", "including", or "having" a constituent element are not exclusive expressions that exclude the existence of other constituent elements.

[0189] Explanation of reference numerals:

[0190] 1 Rolling equipment

[0191] 2 Rolling device

[0192] 4 Uncoiler

[0193] 6 Input side pinch roll

[0194] 10 Rolling stand

[0195] 12 Output side pinch roll

[0196] 14 Rewinder

[0197] 15 Rolling roll

[0198] 16 Rolling roll

[0199] 17 Intermediate roll

[0200] 18 Intermediate roll

[0201] 19 Backup roll

[0202] 20 Backup roll

[0203] 30 Detection unit

[0204] 30A Upstream detection unit

[0205] 30B Downstream detection unit

[0206] 30C First end-side detection unit

[0207] 30D Second end-side detection unit

[0208] 32 Radiation generation unit

[0209] 34 Radiation light-receiving unit

[0210] 36 Element

[0211] 36A, 36A’ First element

[0212] 36B Second element

[0213] 50 Processing unit

[0214] 52 Plate end position determination unit

[0215] 52A Upstream side plate end position determination unit

[0216] 52B Downstream side plate end position determination unit

[0217] 52C First end-side plate end position determination unit

[0218] 52D Second end-side plate end position determination unit

[0219] 54 Edge crack detection unit

[0220] 54A Upstream side edge crack detection unit

[0221] 54B Downstream side edge crack detection unit

[0222] 54C First end-side edge crack detection unit

[0223] 54D Second end-side edge crack detection unit

[0224] 56 First determination unit

[0225] 58 Second determination unit

[0226] 100 Edge crack detection device

[0227] 101 Radiation

[0228] E Plate end

[0229] E1 First end

[0230] E2 Second end

[0231] R1 First region

[0232] R2 Second region

[0233] S Metal plate.

Claims

1. An edge crack detection device for detecting edge cracks of a transported metal plate, wherein, the edge crack detection device includes a detection unit, and the detection unit includes a plurality of elements arranged along the plate width direction of the metal plate, each of the plurality of elements is configured to be able to detect whether the metal plate exists at a position in the plate width direction of the element, the edge crack detection device includes: a plate end position determination unit configured to determine the plate end position in the plate width direction of the metal plate based on the detection results of a plurality of first elements among the plurality of elements, and the plurality of first elements are located in a first area in the plate width direction; and an edge crack detection unit configured to detect edge cracks of the metal plate based on the detection results of a plurality of second elements among the plurality of elements, and the plurality of second elements are selected based on the plate end position and are located in a second area narrower than the first area in the plate width direction, the edge crack detection unit is configured to determine the possibility of the existence of edge cracks in the metal plate based on whether the second elements located at positions inside the plate end position among the plurality of second elements detect the absence of the metal plate, the edge crack detection device includes: a first end side edge crack detection unit as the edge crack detection unit; a second end side edge crack detection unit as the edge crack detection unit, which is arranged on the opposite side of the first end side edge crack detection unit across the metal plate in the plate width direction; and a second determination unit configured to determine that there are edge cracks on the metal plate when, at the same time, the first end side edge crack detection unit determines that there is a possibility of the existence of the edge crack, and in the second end side edge crack detection unit, the second elements located at positions outside the plate end position in the plate width direction do not detect the existence of the metal plate.

2. An edge crack detection device for detecting edge cracks of a transported metal plate, wherein, the edge crack detection device includes a detection unit, and the detection unit includes a plurality of elements arranged along the plate width direction of the metal plate, each of the plurality of elements is configured to be able to detect whether the metal plate exists at a position in the plate width direction of the element, the edge crack detection device includes: a plate end position determination unit configured to determine the plate end position in the plate width direction of the metal plate based on the detection results of a plurality of first elements among the plurality of elements, and the plurality of first elements are located in a first area in the plate width direction; and an edge crack detection unit configured to detect edge cracks of the metal plate based on the detection results of a plurality of second elements among the plurality of elements, and the plurality of second elements are selected based on the plate end position and are located in a second area narrower than the first area in the plate width direction, the plate end position determination unit is configured to obtain the detection results of the plurality of first elements every first cycle time and determine the plate end position based on the detection results, The edge crack detection unit is configured to obtain the detection results of each of the plurality of second elements every second cycle time, and the second cycle time is shorter than the first cycle time.

3. The edge crack detection device according to claim 2, wherein the second cycle time is 1 / 10 or less of the first cycle time.

4. The edge crack detection device according to claim 2 or 3, wherein the plate end position determination unit is configured to sequentially read the states of the plurality of first elements along the plate width direction every first cycle time, thereby obtaining the detection results of the plurality of first elements during the first cycle time.

5. The edge crack detection device according to claim 2 or 3, wherein the edge crack detection unit is configured to sequentially read the states of the plurality of second elements along the plate width direction every second cycle time, thereby obtaining the detection results of the plurality of second elements during the second cycle time.

6. The edge crack detection device according to claim 1 or 2, wherein the edge crack detection unit is configured to detect the edge crack based on the number of the second elements among the plurality of second elements that detect the following situation: the metal plate does not exist at the position in the plate width direction of the second element.

7. The edge crack detection device according to claim 6, wherein the edge crack detection unit is configured to determine that an edge crack exists on the metal plate when a predetermined number or more of the second elements arranged continuously among the plurality of second elements each detect the non-existence of the metal plate.

8. The edge crack detection device according to claim 6, wherein the edge crack detection unit is configured to determine that an edge crack exists on the metal plate when the ratio of the number of the second elements that detect the non-existence of the metal plate to the number of the plurality of second elements is equal to or greater than a predetermined value.

9. The edge crack detection device according to claim 1 or 2, wherein the second region is a region between the plate end position and a position shifted inward in the plate width direction from the plate end position.

10. The edge crack detection device according to claim 2 or 3, wherein the edge crack detection unit is configured to determine the possibility of an edge crack existing in the metal plate based on whether the second elements among the plurality of second elements located at positions closer to the inside than the plate end position detect the non-existence of the metal plate. The edge crack detection device includes: an upstream edge crack detection unit as the edge crack detection unit; a downstream edge crack detection unit as the edge crack detection unit, which is provided at a position different from the upstream edge crack detection unit in the conveyance direction of the metal plate; and a first determination unit configured to determine that an edge crack exists on the metal plate when only one of the upstream edge crack detection unit and the downstream edge crack detection unit determines the possibility of the existence of the edge crack at the same time.

11. The edge crack detection device according to claim 1 or 2, wherein The detection unit includes: a radiation light-receiving unit including a plurality of the elements; and a radiation generating unit disposed on the side opposite to the radiation light-receiving unit with the metal plate interposed therebetween and configured to generate radiation directed toward the radiation light-receiving unit, each of the plurality of the elements is configured to detect that the metal plate does not exist at a position in the plate width direction of the element when receiving the radiation, and to detect that the metal plate exists at a position in the plate width direction of the element when not receiving the radiation.

12. A rolling device, comprising: a rolling device configured to roll a metal plate; and the edge crack detection device according to claim 1 or 2, configured to detect an edge crack at an end in the plate width direction of the metal plate during rolling by the rolling device.

13. An edge crack detection method, which uses a detection unit including a plurality of elements arranged along the plate width direction of a metal plate to detect an edge crack of the transported metal plate, wherein each of the plurality of the elements is configured to be able to detect whether the metal plate exists at a position in the plate width direction of the element, the edge crack detection method includes the following steps: determining a plate end position in the plate width direction of the metal plate based on the detection results of a plurality of first elements located in a first region in the plate width direction among the plurality of the elements; selecting a plurality of second elements located in a second region narrower than the first region in the plate width direction from among the plurality of the elements based on the determined plate end position; and detecting an edge crack of the metal plate based on the detection results of the selected plurality of the second elements, in the step of detecting the edge crack, based on whether a second element located at a position closer to the inside than the plate end position among the plurality of the second elements detects that the metal plate does not exist, determining the possibility of an edge crack existing in the metal plate, performing the step of detecting the edge crack using a first end-side edge crack detection unit, performing the step of detecting the edge crack using a second end-side edge crack detection unit disposed on the side opposite to the first end-side edge crack detection unit with the metal plate interposed therebetween in the plate width direction, the edge crack detection method further includes the following step: when, at the same time, the first end-side edge crack detection unit determines that there is a possibility of the edge crack, and in the second end-side edge crack detection unit, a second element located at a position closer to the outside than the plate end position in the plate width direction does not detect the existence of the metal plate, determining that an edge crack exists in the metal plate.

14. An edge crack detection method, which uses a detection unit including a plurality of elements arranged along the plate width direction of a metal plate to detect an edge crack of the transported metal plate, wherein each of the plurality of the elements is configured to be able to detect whether the metal plate exists at a position in the plate width direction of the element, the edge crack detection method includes the following steps: Based on the detection results of a plurality of first elements located within a first region in the plate width direction among the plurality of elements, determine the plate end position in the plate width direction of the metal plate; Based on the determined plate end position, select a plurality of second elements located within a second region narrower than the first region in the plate width direction from among the plurality of elements; And Detect the edge crack of the metal plate based on the detection results of the selected plurality of second elements; In the step of determining the plate end position, obtain the detection results of the plurality of first elements every first cycle time, and determine the plate end position based on the detection results; In the step of detecting the edge crack, obtain the detection results of the plurality of second elements every second cycle time, and the second cycle time is shorter than the first cycle time.

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