JP5867069B2 - Defect detection apparatus and evacuation method thereof - Google Patents

Description

  The present invention relates to a defect detection apparatus having a function of retracting a defect detection unit that detects a defect of a material to be inspected, and a method for retracting the defect detection apparatus.

  2. Description of the Related Art Conventionally, in a production line for steel products, a defect detection unit that detects defects generated on the surface of a steel material such as a steel strip or a steel plate used for the production of steel products is appropriately arranged. Generally, a production line for steel products manufactures steel products such as sheet products or coil products by carrying out various treatments on the steel materials while conveying the steel materials that are input.

  As an example of such a defect detection unit in a production line, a mechanical convex defect detection unit having a detection mechanism such as a pendulum is known. The mechanical convex defect detection unit arranges a detection mechanism above the steel material transported in the production line, and makes the steel material bend or curved by bringing this detection mechanism into contact with the defective portion of the steel material surface. To detect a convex defect caused by a restriction or the like generated on the surface of the steel material.

  On the other hand, surface defects such as wrinkles or dirt may occur on the surface of the steel material. In order to detect such surface defects, the production line has a defect detection unit that optically detects surface defects. Is placed. For example, the optical defect detection unit has a light emitting unit and a light receiving unit, irradiates the steel material surface with predetermined light to receive reflected light from the steel plate surface, and based on the received reflected light, Detect surface defects in steel materials. The optical defect detection unit captures an image of the illuminated steel material range, that is, the defect inspection range, and the area, width, length, shape, and brightness of the defect portion captured in the obtained image. Based on such information, the type and level of the detected surface defect are identified.

  In addition to the above, the convex defect detection unit that detects convex defects on the surface of the steel material has, for example, a light projecting unit and a light receiving unit that project and receive laser light, and has a width in the thickness direction of the steel plate. Passing the laser beam directly above the surface of the steel material, and detecting whether or not this laser beam is blocked by the aperture defect, which is a convex part formed on the surface of the steel material, detects the aperture defect (convex defect) on the iron plate surface There is a laser-type defect detection unit (see Patent Document 1).

JP-A-9-257442

  By the way, in order to manufacture a high-quality steel product, it is necessary to inspect not only the convex defects on the surface of the steel material such as the above-described drawing defects but also internal defects such as wrinkles or voids generated in the steel material. . In recent years, as a device for detecting such an internal defect of a steel material, a leakage flux type defect detection unit has been used in a production line for steel products.

  The leakage flux type defect detection unit magnetizes the steel material by applying a magnetic force to the steel material flowing in the production line, and detects the internal defect of the steel material based on the magnetic flux leaking from the defective part of the magnetized steel material To do. Such a leakage magnetic flux type defect detection unit generally includes a magnetic flux detection unit that detects magnetic flux leaking from a defective portion of the steel material.

  The detection accuracy of internal defects by such a leakage magnetic flux type defect detection unit changes according to the separation distance between the steel material surface and the magnetic flux detection unit. Specifically, the detection accuracy of the internal defect is improved by bringing the magnetic flux detection part closer to the steel material surface and shortening the separation distance between the steel material surface and the magnetic flux detection part. For this reason, in recent years, there is a tendency for the magnetic flux detection unit to be closer to the surface of the steel material in order to increase the accuracy of detection of internal defects in the steel material.

  However, as described above, there may be a convex defect such as a drawing defect on the surface of the steel material. Therefore, there is a possibility that the magnetic flux detection part brought close to the surface of the steel material and the convex defect on the surface of the steel material come into contact with each other. There is. Due to the contact between the magnetic flux detector and the convex defect, the magnetic flux detector may be damaged.

  In recent years, an internal defect detection unit that detects an internal defect of a material to be inspected by bringing a detector such as a magnetic flux detection unit close to the material to be inspected, as exemplified by a leakage magnetic flux type defect detection unit, There is a growing demand to prevent damage to the internal defect detection portion due to contact between the convex defect on the surface of the inspection material and the detector while detecting the internal defect of the inspection material with high accuracy.

  The present invention has been made in view of the above circumstances, and an internal defect detection unit that detects an internal defect of a material to be inspected in the vicinity of the surface of the material to be inspected can be reliably evacuated when necessary. It is an object of the present invention to provide a defect detection apparatus and a retracting method thereof capable of accurately preventing damage to an internal defect detection unit due to contact between a convex defect on a surface of an inspection material and a detector.

  In order to solve the above-described problems and achieve the object, the defect detection apparatus according to the present invention is an internal defect detection unit that detects an internal defect of the inspection object in the vicinity of the surface of the inspection object being conveyed. And a plurality of convex defect detection units for detecting convex defects on the surface of the inspection material located on the upstream side of conveyance compared to the internal defect detection unit, and at least the inspection material A moving unit that moves the internal defect detection unit in a direction away from the surface of the substrate, and the moving unit is controlled based on the detection result of the convex defect to retract the internal defect detection unit from the material to be inspected. And a control unit.

  In the defect detection device according to the present invention, in the above invention, one of the plurality of convex defect detection units captures a surface image of the inspection object, and based on the obtained surface image. It is a surface defect detection part which detects the said convex defect.

  In the defect detection apparatus according to the present invention as set forth in the invention described above, the moving unit moves the internal defect detection unit after retreating in a direction approaching the surface of the inspection object, and the control unit At a timing after a defect has passed the detection position of the internal defect detection unit, the moving unit is controlled to bring the internal defect detection unit close to the surface of the inspection object.

  The defect detection apparatus according to the present invention further includes a measurement unit that measures the conveyance distance of the inspection object in the above invention, and the control unit is based on the measurement result of the conveyance distance by the measurement unit. Furthermore, the moving part is controlled at a timing before the convex defect passes through the detection position of the internal defect detecting part, and the internal defect detecting part is retreated from the material to be inspected.

  In the defect detection device according to the present invention, in the above invention, the control unit may cause the convex defect to pass through a detection position of the internal defect detection unit based on a measurement result of the transport distance by the measurement unit. The moving part is controlled at the timing after the operation, and the internal defect detecting part is brought close to the surface of the inspection object.

  Further, the defect detecting apparatus according to the present invention includes a method for retracting a surface of a material to be inspected by using at least one convex defect detecting unit among a plurality of convex defect detecting units that respectively detect convex defects on the surface of a material to be inspected by different methods. When the convex defect is detected, the internal defect detection unit is moved in a direction away from the surface of the inspection material, and the internal defect detection unit is retreated from the inspection material.

  Further, the defect detection apparatus retreat method according to the present invention is the above invention, wherein the internal defect detection unit after retraction is applied to the covered defect at a timing after the convex defect has passed the detection position of the internal defect detection unit. It is moved in a direction approaching the surface of the inspection material, and the internal defect detector is brought close to the surface of the inspection material.

  According to the present invention, the internal defect detection unit that detects the internal defect of the inspection material close to the surface of the inspection material can be reliably retracted when necessary, and as a result, the convex defect on the surface of the inspection material and the detector There is an effect that damage to the internal defect detection part due to contact can be prevented accurately.

FIG. 1 is a schematic diagram illustrating a configuration example of a defect detection apparatus according to an embodiment of the present invention. FIG. 2 is a schematic diagram illustrating a state in which the internal defect detection unit is retracted from the convex defect on the surface of the steel material. FIG. 3 is a schematic diagram illustrating a state in which the internal defect detection unit after retraction is returned to the original detection position. FIG. 4 is a schematic diagram showing a modification of the defect detection apparatus according to the embodiment of the present invention.

  Exemplary embodiments of a defect detection apparatus and a retraction method thereof according to the present invention will be explained below in detail with reference to the accompanying drawings. In the following, a strip-shaped steel material flowing through a steel product production line is exemplified as an example of the material to be inspected, but the present invention is not limited to this embodiment.

(Embodiment)
First, the configuration of the defect detection apparatus according to the embodiment of the present invention will be described. FIG. 1 is a schematic diagram illustrating a configuration example of a defect detection apparatus according to an embodiment of the present invention. As shown in FIG. 1, the defect detection apparatus 1 includes convex defect detection units 2 and 3 that detect convex defects such as a drawing defect generated on the surface of the steel material 15, and wrinkles and dirt generated on the surface of the steel material 15. The surface defect detection part 4 which detects this surface defect, and the internal defect detection part 5 which detects internal defects, such as a flaw and a space | gap which arise in the inside of the steel material 15, are provided. In addition, the defect detection apparatus 1 includes a moving unit 6 that moves the internal defect detection unit 5 relative to the steel material 15, a measurement unit 7 that measures the transport distance of the steel material 15, and an input for inputting various information. Unit 8 and a control unit 9 that controls the retreat operation of the defect detection apparatus 1.

  The steel material 15 shown in FIG. 1 is a part of the entire steel material flowing in the production line of steel products, and is sequentially conveyed by a conveyance mechanism such as a conveyance roll (not shown) of the production line. On the other hand, as shown in FIG. 1, two convex defect detection units 2 and 3, a surface defect detection unit 4, and an internal defect detection unit 5 having different detection methods are included in the production line. They are arranged along the transport direction (the direction of the thick arrow shown in FIG. 1). That is, the steel material 15 sequentially passes through the convex defect detector 2, the convex defect detector 3, the surface defect detector 4, and the internal defect detector 5 in this order while being conveyed.

  The convex defect detection unit 2 is a mechanical type that detects a convex defect using physical contact between a predetermined detector and a convex portion of the convex defect. Specifically, the convex defect detector 2 has a wire 2a as a detector. The wire 2 a is a heat-resistant wire such as a metal that can withstand the temperature of the steel material 15, and is formed longer than the width of the steel material 15. The convex defect detection unit 2 supports the wire 2a above the steel material 15 as shown in FIG. 1 while applying an appropriate tension to the wire 2a in the width direction of the steel material 15. In this case, the wire 2 a extends in the width direction of the steel material 15, and has an appropriate height as a mechanical convex defect detection method across the width direction of the steel material 15, for example, a normal surface of the steel material 15. Is stretched to a height of about 1 to 2 mm.

  The convex defect detection unit 2 configured in this manner detects a convex part physically contacting the wire 2a as a convex defect among convex defect parts such as a drawing defect generated on the surface of the steel material 15. When the convex defect detection unit 2 detects a convex defect in this way, the convex defect detection unit 2 transmits defect detection information indicating the detection result to the control unit 9. Thereby, the convex defect detector 2 informs the controller 9 that a convex defect on the surface of the steel material 15 has been detected.

  The convex defect detector 3 is of a laser type that detects a convex defect using optical contact between a laser beam to be projected and received and a convex defect. Specifically, the convex defect detection unit 3 includes a light emitting unit 3a that emits laser light and a light receiving unit 3b that receives the laser light from the light emitting unit 3a. The light emitting unit 3a is realized using a laser light emitting element or the like, and emits laser light having a predetermined width. The light receiving unit 3b is realized by using a light receiving element or the like, and receives the laser light emitted from the light emitting unit 3a. As shown in FIG. 1, the light emitting unit 3 a and the light receiving unit 3 b face each other from both sides of the steel material 15, and project and receive laser light. That is, the light emitting unit 3a has an appropriate height as a laser-type convex defect detection method across the width direction of the steel material 15, for example, a height within 1 mm from the normal surface of the steel material 15. Irradiate laser light substantially parallel to the surface. The light receiving unit 3b receives the laser light emitted from the light emitting unit 3a unless the light receiving unit 3b is shielded by a convex portion such as a diaphragm defect.

  The convex defect detection unit 3 configured in this way crosses the laser light projected and received by the light emitting unit 3a and the light receiving unit 3b among the convex portions generated on the surface of the steel material 15, and before entering the light receiving unit 3b. The convex portion that shields the laser beam is detected as a convex defect. When the convex defect detection unit 3 detects the convex defect in this way, the convex defect detection unit 3 transmits defect detection information indicating the detection result to the control unit 9. Thereby, the convex defect detection part 3 notifies the control part 9 that the convex defect of the steel material 15 surface was detected.

  The surface defect detection unit 4 mainly detects surface defects such as wrinkles or dirt generated on the surface of the steel material 15. Specifically, the surface defect detection unit 4 is realized by using a light emitting element, an image pickup element, and the like, and picks up a surface image of the steel material 15 to detect a surface defect or the like of the steel material 15. That is, the surface defect detection unit 4 illuminates the surface inspection range of the steel material 15, receives reflected light from the surface inspection range, and captures a surface image of the steel material 15. Note that the surface inspection range of the steel material 15 is captured in the obtained surface image. Next, the surface defect detection unit 4 finds a characteristic portion in the surface image based on pixel information such as luminance, chromaticity, and received light amount of each pixel of the obtained surface image. Next, the surface defect detection unit 4 detects surface defects such as wrinkles and dirt of the steel material 15 from the feature portion based on information such as the area, width, length, shape, brightness and darkness of the feature portion. To do.

  Furthermore, as described above, the surface defect detection unit 4 that picks up the surface image of the steel material 15 and detects surface defects or the like of the steel material 15 also functions as a convex defect detection unit that detects convex defects. Specifically, the surface defect detection unit 4 identifies the type and level of the detected surface defect based on information such as the area, width, length, shape, brightness, and darkness of the characteristic portion in the surface image described above. At the same time, the height of the defect is detected based on the identified surface defect information. That is, the surface defect detection unit 4 estimates the height of the defect from past information regarding the defect based on the information (type, level, etc.) of the identified defect. The detection of the defect height can be performed based on, for example, a table in which the type or level of the surface defect is associated with the defect height based on various inspection results of the surface defect. In addition, the height of this defect is a protruding height from the surface of the steel material 15. That is, the surface defect detection part 4 detects the convex defect of the steel material 15 identified from the characteristic part in a surface image, when the height of this detected defect is more than a predetermined threshold value. Thereafter, when the surface defect detection unit 4 detects the convex defect in this manner, the surface defect detection unit 4 transmits defect detection information indicating the detection result to the control unit 9. Thereby, the surface defect detection part 4 notifies the control part 9 that the convex defect of the steel material 15 surface was detected. Or the surface defect detection part 4 may judge whether it is a convex defect directly, without detecting defect height based on surface defect information, such as a kind and level of a surface defect.

  The internal defect detection unit 5 is for detecting internal defects such as wrinkles or voids generated in the steel material 15. Specifically, the internal defect detection unit 5 is realized using a leakage magnetic flux detection sensor or the like, and has a detector 5a for detecting internal defects. As shown in FIG. 1, the detector 5 a has a width equivalent to the width of the steel material 15 (the length of the steel material in the direction perpendicular to the conveying direction), and from the surface of the steel material 15 to the separation distance H. Proximity. This separation distance H is, for example, about 0.4 to 1.0 mm. The internal defect detection unit 5 is supported by the moving unit 6 in such a manner that the state in which the detector 5a is brought close to the surface of the steel material 15 is maintained.

  Such an internal defect detection unit 5 detects a physical quantity such as a leakage magnetic flux from the steel material 15 by the detector 5a, and based on the detected physical quantity, the internal defect detection unit 5 covers the entire range of the steel material 15 in the width direction. Detect defects. For example, when the internal defect detection unit 5 is of a leakage magnetic flux type, the internal defect detection unit 5 magnetizes the steel material 15 by the detector 5a and emits from the surface of the steel material 15 when an internal defect has occurred. The detected magnetic flux is detected by the detector 5a. The internal defect detector 5 detects internal defects of the steel material 15 based on the detected leakage magnetic flux.

  The moving unit 6 is for moving the internal defect detecting unit 5 in a direction away from at least the surface of the steel material 15. Specifically, the moving unit 6 is realized by using a transfer mechanism such as a guide unit and a drive unit, and although not particularly illustrated, the thickness direction of the steel material 15 from the surface of the steel material 15 (that is, above the steel material 15). Has a transfer path to The moving unit 6 maintains the state in which the surface of the steel material 15 and the detector 5a are separated from each other by a distance H or more, and an internal defect in a direction away from the surface of the steel material 15 based on an instruction from the control unit 9. The detection unit 5 is transferred. In this case, the moving part 6 transfers the internal defect detection part 5 to the upper direction of the steel material 15, as shown by the broken line arrow of FIG. As a result, the moving unit 6 retracts the internal defect detection unit 5 to a position separated from the steel material 15 such as an upper position of the steel material 15, and the detector 5 a of the internal defect detection unit 5 and the convex defect of the steel material 15. To avoid collisions.

  On the other hand, the moving unit 6 can move the internal defect detection unit 5 after retraction in a direction approaching the surface of the steel material 15 to return the internal defect detection unit 5 to the original detection position. Specifically, the moving unit 6 retracts the internal defect detection unit 5 to a position above the steel material 15 and then approaches the surface of the steel material 15 based on an instruction from the control unit 9 (shown in FIG. 1). The internal defect detector 5 after the retraction is transferred to the original detection position (in the direction opposite to the dashed arrow). Thereby, as shown in FIG. 1, the moving unit 6 is a position close to the surface of the steel material 15 up to the separation distance H and is a fixed position when detecting an internal defect of the steel material 15, that is, the original detection position. The internal defect detector 5 is returned to the state.

  The measurement part 7 measures the conveyance distance of the steel material 15 conveyed. Specifically, the measuring unit 7 is realized by using a roll having a predetermined radius that rotates in accordance with the conveying operation of the steel material 15. The roll having a predetermined radius may be, for example, a roll installed in the production line, and the measurement unit 7 measures the transport distance based on the rotation speed, circumference, and the like of the roll. Each time the measurement unit 7 measures the conveyance distance as described above, the measurement unit 7 sequentially transmits the measured conveyance distance to the control unit 9.

  The input unit 8 is realized by using an input device such as an input key or a mouse, and inputs various types of information to the control unit 9 in accordance with an input operation by an operator. Specifically, the input unit 8 includes instruction information for instructing the operation start or operation stop of the defect detection apparatus 1, the convex defect detection units 2 and 3, the surface defect detection unit 4 and the internal defect detection unit 5. The distance information indicating the distance and other information useful for the retreat operation of the internal defect detection unit 5 as exemplified by the transfer speed of the internal defect detection unit 5 are input to the control unit 9.

  The control unit 9 is realized by using a storage unit that stores a program or the like for realizing the function of the defect detection apparatus 1 and a CPU or the like that executes a program in the storage unit. The control unit 9 includes each component of the defect detection apparatus 1, that is, each of the convex defect detection units 2 and 3, the surface defect detection unit 4, the internal defect detection unit 5, the moving unit 6, the measurement unit 7, and the input unit 8. The operation is controlled, and input / output of electric signals to / from each of these components is controlled.

  Specifically, the control unit 9 controls the start and stop of each operation of the convex defect detection units 2 and 3, the surface defect detection unit 4, and the internal defect detection unit 5 based on the input information of the input unit 8. To do. Further, the control unit 9 controls the operation timing of the moving unit 6 based on the measurement result of the transport distance of the steel material 15 by the measurement unit 7, and the convex defect detection units 2 and 3, surface defects are controlled at this operation timing. Based on the detection results of the detection unit 4 and the internal defect detection unit 5, the moving unit 6 is controlled to retract the internal defect detection unit 5 from the steel material 15.

  In the retraction control of the internal defect detection unit 5, the control unit 9 performs the convex defect detection units 2, 3 and the surface defect detection unit based on the detection results of the convex defect detection units 2, 3 and the surface defect detection unit 4. 4 is used to grasp which convex defect of the steel material 15 is detected, and based on this, the distance from the detection position of the convex defect to the internal defect detection unit 5 is grasped. Further, the control unit 9 grasps the transport position of the steel material 15 based on the transport distance measured by the measurement unit 7. Further, the control unit 9 grasps the transport distance from the detection position of the convex defect based on the detection results of the convex defect detection units 2 and 3 and the surface defect detection unit 4 and the measurement result of the measurement unit 7. . Based on each piece of information thus grasped, the control unit 9 controls the moving unit 6 at a timing before the detected convex defect passes through the detection position of the internal defect detection unit 5, and the steel material 15 The internal defect detection unit 5 is withdrawn.

  On the other hand, the control unit 9 performs control for retracting the internal defect detection unit 5 from the convex defect as described above, and then detects the distance from the detection position of the convex defect to the internal defect detection unit 5 and the detection of the convex defect. Based on the transport distance from the position, it is determined whether or not the convex defect has passed the internal defect detection position. The control unit 9 maintains the internal defect detection unit 5 in a retracted state until the convex defect passes through the detection position of the internal defect detection unit 5, and the convex defect passes through the detection position of the internal defect detection unit 5. The moving part 6 is controlled at a later timing, and the internal defect detecting part 5 is brought close to the surface of the steel material 15.

  In addition, the control part 9 controls the internal defect detection part 5 so that the internal defect detection operation | movement of the steel material 15 may be stopped, when the internal defect detection part 5 is evacuated from a convex defect as mentioned above. On the other hand, when the control unit 9 brings the internal defect detection unit 5 after retraction close to the surface of the steel material 15 and returns the internal defect detection unit 5 to the original detection position as described above, The internal defect detector 5 is controlled to resume the internal defect detection operation.

  Here, the convex defect detection units 2 and 3 and the surface defect detection unit 4 described above constitute a plurality of convex defect detection units in the defect detection apparatus 1. Specifically, the plurality of convex defect detectors use different defect detection methods, and as shown in FIG. 1, the convexity of the surface of the steel material 15 located upstream of the internal defect detector 5 as compared with the internal defect detector 5. Each defect is detected. In the plurality of convex defect detectors, at least one of the convex defect detectors 2 and 3 and the surface defect detector 4 detects a convex defect that is not detected by the remaining convex defect detectors. As a result, the convex defect detection units 2 and 3 and the surface defect detection unit 4 compensate each other for the lack of detection capability and the disadvantage at the time of detection. Detection is performed without leakage at the front stage of the defect detection unit 5.

  In addition, the convex defect detection result of the convex defect detection units 2 and 3 described above, the surface defect detection result of the surface defect detection unit 4 and the internal defect detection result of the internal defect detection unit 5 are different from the detection result of the convex defect. It is transmitted to an external device such as a defect management device. Various defects generated in the steel material 15 are managed by the external device. The control unit 9 is not limited to the above-described embodiment, and may control the operation timing of the moving unit 6 based on at least the detection result of the convex defect. For example, the convex defect detection units 2 and 3 and the surface defect Each operation of the detection unit 4 and the internal defect detection unit 5 may be separately controlled by each independent control unit.

  Next, a method for retracting the defect detection apparatus 1 according to the embodiment of the present invention will be described. FIG. 2 is a schematic diagram illustrating a state in which the internal defect detection unit is retracted from the convex defect on the surface of the steel material. FIG. 3 is a schematic diagram illustrating a state in which the internal defect detection unit after retraction is returned to the original detection position. Hereinafter, with reference to FIGS. 1-3, the retraction | saving method of the defect detection apparatus 1, ie, the retraction | saving method of the internal defect detection part 5 from the convex defect which arose on the surface of the steel material 15, is demonstrated in detail.

  As shown in FIG. 1, the steel material 15 is conveyed by a conveyance mechanism (not shown) such as a conveyance roll, while the convex defect detection unit 2, the convex defect detection unit 3, the surface defect detection unit 4, and the internal defect detection unit 5. The detection positions are sequentially passed in this order. The convex defect detection units 2 and 3 and the surface defect detection unit 4 sequentially perform convex defect detection processing on the steel material 15 being conveyed. As long as there is no convex defect on the surface of the steel material 15, the internal defect detector 5 brings the detector 5 a close to the surface of the normal steel material 15 without the convex defect to a separation distance H, and the inside of the steel material 15. Defect detection processing is performed sequentially.

  Here, when a convex defect exists on the surface of the steel material 15, the convex defect is detected by the convex defect detection unit 2, the convex defect detection unit 3, and the surface defect detection unit 4 as the steel material 15 is conveyed. The position is sequentially passed in this order. In this case, the defect detection apparatus 1 first detects the convex defect by at least one of the convex defect detection units 2 and 3 and the surface defect detection unit 4. Next, the defect detection apparatus 1 moves the internal defect detection unit 5 in a direction away from the surface of the steel material 15 where the convex defect exists, and thereby retracts the internal defect detection unit 5 from the steel material 15. .

  Specifically, the convex defect 15a on the surface of the steel material 15 detected by at least one of the convex defect detection units 2 and 3 and the surface defect detection unit 4 is combined with the steel material 15 as shown in FIG. It is conveyed to the internal defect detector 5 side. At the same time, the control unit 9 performs arithmetic processing and the like based on the detection results of the convex defect detection units 2 and 3 and the surface defect detection unit 4 and the measurement result of the conveyance distance by the measurement unit 7. The distance L1 from the detection position P1 of the convex defect 15a shown in FIG. 2 to the detection position P2 of the internal defect detection unit 5 and the current conveyance distance L2 of the convex defect 15a starting from the detection position P1 are grasped.

  The detection position P1 shown in FIG. 2 is a position where the convex defect 15a is detected by at least one of the convex defect detection units 2 and 3 and the surface defect detection unit 4. That is, the detection position P1 is any one of the convex defect detection units 2 and 3 and the surface defect detection unit 4 that detect the convex defect 15a.

  The control unit 9 may set the position at which the convex defect 15a is first detected among the detection positions of the convex defect detection units 2 and 3 and the surface defect detection unit 4 as the detection position P1, or finally the convex position. The position where the defect 15a is detected may be set as the detection position P1. Alternatively, when the control unit 9 is detected by all of the convex defect detection units 2 and 3 and the surface defect detection unit 4, the position where the convex defect 15a is detected secondly among the three detection positions of the convex defect 15a. May be set as the detection position P1. In any case, as long as the detection position P1 is determined before the convex defect 15a reaches the detection position P2 of the internal defect detection unit 5, the detection position P1 may be any detection position of the convex defect 15a.

  On the other hand, after calculating the distance L1 between the two detection positions P1 and P2, the control unit 9 continuously acquires the measurement result of the conveyance distance by the measurement unit 7, and based on the acquired measurement result, The conveyance distance L2 of the defect 15a is sequentially updated to the latest one. At the same time, the control unit 9 monitors the latest transport distance L2 and the distance L1, and in a state where the transport distance L2 <the distance L1, that is, the state before the convex defect 15a reaches the position of the internal defect detection unit 5. Know if there is.

  Subsequently, the control unit 9 moves the moving unit 6 during a period in which the magnitude relationship of the conveyance distance L2 <the distance L1 is maintained, that is, at a timing before the convex defect 15a reaches the detection position P2 of the internal defect detection unit 5. As shown in FIG. 2, the internal defect detector 5 a is retracted from the steel material 15. In this case, the control unit 9 considers the transfer speed of the internal defect detection unit 5 by the moving unit 6 and the conveyance speed of the convex defect 15 a, and the internal defect detection unit in the direction in which the moving unit 6 is separated from the surface of the steel material 15. The operation start timing of the moving unit 6 is controlled so that the internal defect detection unit 5 (particularly the detector 5a) and the convex defect 15a do not come into contact with each other during the transfer.

  The moving unit 6 starts the transfer of the internal defect detection unit 5 at a timing before the convex defect 15a reaches the detection position P2 of the internal defect detection unit 5 based on the timing control of the control unit 9 as described above. Thereafter, the moving unit 6 moves away from the surface of the steel material 15 without bringing the internal defect detection unit 5 and the convex defect 15a into contact with each other (for example, upward direction of the steel material 15 indicated by the broken arrow in FIG. 2). The internal defect detector 5 is transferred. As a result, as shown in FIG. 2, the internal defect detection unit 5 is safely retracted to a position sufficiently separated from the surface of the steel material 15 without being in contact with the convex defect 15 a.

  After the internal defect detector 5 has been retracted in this way, the controller 9 continues to monitor the latest transport distance L2 and distance L1, and the state where the transport distance L2 ≧ distance L1, that is, the convex defect 15a is internal. The moving unit 6 is controlled so as to maintain the above-described retracted state of the internal defect detecting unit 5 until it passes through the position of the defect detecting unit 5.

  On the other hand, when the latest transport distance L2 described above exceeds the distance L1, the convex defect 15a is located on the transport downstream side as compared with the detection position P2 of the internal defect detection unit 5. As described above, when the magnitude relationship of the latest transport distance L2> distance L1 is established, the control unit 9 determines that the convex defect 15a has passed the detection position P2 of the internal defect detection unit 5.

  Subsequently, as shown in FIG. 3, the control unit 9 is a period in which the magnitude relationship of transport distance L <b> 2> distance L <b> 1 is maintained, that is, after the convex defect 15 a has passed the detection position P <b> 2 of the internal defect detection unit 5. At this timing, the moving unit 6 is controlled to bring the internal defect detection unit 5a after retraction closer to the surface of the steel material 15. In this case, the control unit 9 considers the transfer speed of the internal defect detection unit 5 by the moving unit 6 and the conveyance speed of the convex defect 15a, and the internal defect after retreating in the direction in which the moving unit 6 approaches the surface of the steel material 15. The operation start timing of the moving unit 6 is controlled so that the internal defect detecting unit 5 and the convex defect 15a do not come into contact with each other while the detecting unit 5 is transferred.

  The moving unit 6 starts the transfer of the internal defect detection unit 5 at a timing after the convex defect 15a passes the detection position P2 of the internal defect detection unit 5 based on the timing control of the control unit 9 as described above. Thereafter, the moving unit 6 transfers the internal defect detection unit 5 after retreating in a direction approaching the surface of the steel material 15 (see the broken line arrow in FIG. 3) without bringing the internal defect detection unit 5 and the convex defect 15a into contact with each other. To do. As a result, as shown in FIG. 3, the internal defect detector 5 returns to the detection position P2 after the convex defect 15a passes without contacting the convex defect 15a.

  As described above, the defect detection apparatus 1 retracts the internal defect detection unit 5 from the surface of the steel material 15 when necessary, thereby reliably avoiding contact between the convex defect 15a and the internal defect detection unit 5. Furthermore, the defect detection apparatus 1 makes the internal defect detection unit 5 after being retracted at an appropriate timing close to the surface of the steel material 15, thereby preventing the convex defect 15 a and the internal defect detection unit 5 from contacting each other. The internal defect detection processing of the steel material 15 by the defect detection unit 5 is continued.

  Here, in the above-described retraction method of the defect detection apparatus 1, the convex defect 15 a is detected by at least one of the convex defect detection units 2 and 3 and the surface defect detection unit 4 located in the preceding stage of the internal defect detection unit 5. Is done. In this case, the convex defect detection units 2 and 3 and the surface defect detection unit 4 detect the convex defect 15a while complementing each other's disadvantages and deficiencies in detection capability at the time of convex defect detection.

  Specifically, if the convex defect 15a is a defect that is easily detected by the convex defect detector 2, the convex defect detector 2 detects the convex defect 15a without omission. However, if the convex defect 15a is a defect that is difficult for the convex defect detector 2 to detect (for example, a minute convex defect having a height of 1 mm or less), the convex defect detector 2 may fail to detect the convex defect 15a. . In this case, at least one of the convex defect detection unit 3 and the surface defect detection unit 4 in the subsequent stage detects the convex defect 15a.

  On the other hand, if the convex defect 15a is a defect that is easily detected by the convex defect detector 3, the convex defect detector 3 normally detects the convex defect 15a without omission. However, the convex defect detector 3 may fail to detect the convex defect 15a due to the environment when the convex defect 15a is detected. Specifically, the convex defect detector 3 is highly likely to fail to detect the convex defect 15a when the optical axis of the laser beam is shifted due to vibration generated during detection. In this case, the subsequent surface defect detection unit 4 detects the convex defect 15a. Since the surface defect detection unit 4 is not affected by vibration as compared with the laser-type convex defect detection unit 3, even if vibration occurs during detection, the surface defect detection unit 4 detects this defect without omission. Alternatively, the convex defect 15a may have already been detected by the convex defect detection unit 2 in the previous stage. In any case, the convex defect 15a that the convex defect detector 3 fails to detect is detected by at least one of the convex defect detector 2 and the surface defect detector 4.

  On the other hand, if the convex defect 15a is a defect that is easily detected by the surface defect detection unit 4, the surface defect detection unit 4 detects the convex defect 15a without omission. However, if the convex defect 15a is a defect that is difficult for the surface defect detection unit 4 to detect, the surface defect detection unit 4 may fail to detect the convex defect 15a.

  Here, the surface defect detection unit 4 does not directly detect the height of the convex defect by physically or optically contacting the convex defect, but illuminates and images the surface of the steel material 15 as described above. A convex defect is detected based on the surface image. Therefore, even if the convex defect 15a is actually a convex defect having a height to be detected, if the convex defect has few two-dimensional features when viewed from above, the surface defect detection unit 4 It fails to detect the convex defect 15a.

  The two-dimensional features described above are features on a plane when a convex defect is viewed from above. For example, the height difference of the undulation of the convex defect, the difference in brightness between the convex defect and its surroundings, the steel material The two-dimensional size of the convex defect projected on the surface of 15. For example, a defect having a small two-dimensional characteristic is, for example, a fine defect on a plane such as Dents or a defect whose contrast with the surroundings such as a convex defect having a smooth shape does not appear clearly on the image.

  On the other hand, since the mechanical convex defect detector 2 detects the convex defect by bringing the wire 2a and the convex defect into direct contact with each other, even if the convex defect has few two-dimensional features as described above. The convex defect having a height that can contact the wire 2a is detected without omission. Similarly, the laser-type convex defect detector 3 detects the convex defect by the contact between the laser beam projected and received in the width direction of the steel material 15 and the convex defect, so that there are few two-dimensional features as described above. Even if it is a convex defect, the convex defect of the height or shape which can contact a laser beam is detected without omission. Therefore, at least one of the convex defect detection units 2 and 3 detects the convex defect 15a that is difficult to detect by the surface defect detection unit 4 as described above without omission.

  As described above, the convex defect detection units 2 and 3 and the surface defect detection unit 4 compensate for the detection defect of the convex defect, thereby detecting the convex defect 15a of the steel material 15 without leakage. Thereafter, the detected convex defect 15 a is transported to the rear stage side of the convex defect detection units 2 and 3 and the surface defect detection unit 4 as the steel material 15 is transported.

  As described above, in the defect detection apparatus and the retraction method according to the embodiment of the present invention, a plurality of convex defect detection units that respectively detect convex defects on the surface of the steel material being conveyed by different defect detection methods. Among these, the convex defect on the surface of the steel material is detected by at least one convex defect detection unit, and when the convex defect is not detected, the steel defect is detected by the internal defect detection unit adjacent to the surface of the steel material. When a convex defect is detected by performing an internal defect detection process on the material, the internal defect detection unit is moved away from the steel material by moving the internal defect detection unit in a direction away from the surface of the steel material.

  For this reason, while detecting the internal defect of the steel material in a state where the detector of the internal defect detection unit is brought close to a predetermined separation distance on the surface of the steel material, the direction away from the surface of the steel material as necessary The internal defect detector can be transferred to As a result, the internal defects of the steel material can be detected with higher accuracy than before, and the convex defects on the surface of the steel material are sufficiently separated from the surface of the steel material in an emergency when approaching the internal defect detection part. The internal defect detector can be transferred to the position. As a result, the internal defect detection unit can be retracted from the convex defect when necessary without lowering the internal defect detection capability of the steel material, and contact between the convex defect and the internal defect detection unit can be reliably avoided. Damage to the internal defect detector due to contact with the detector of the internal defect detector can be accurately prevented.

  In addition, since the convex defects on the surface of the steel material are detected using a plurality of convex defect detectors that detect the convex defects generated on the surface of the steel material by different defect detection methods, The disadvantages of the defect detection unit and the lack of detection capability can be compensated for among the plurality of convex defect detection units. As a result, a convex defect that one of the plurality of convex defect detectors fails to detect can be detected by at least one of the remaining convex defect detectors. In addition, it is possible to detect a convex defect without omission and to use a high-accuracy detection result of the convex defect for retreat control of the internal defect detection unit, so that the internal defect detection unit can be retreated at a more accurate timing.

  Furthermore, in the defect detection device and the retraction method according to this embodiment, the internal defect detection part after retraction approaches the steel material surface at the timing after the convex defect passes the detection position of the internal defect detection part. Is moving in the direction. For this reason, the internal defect detection part after retraction | saving can be returned to the original detection position at the appropriate timing in which a convex defect does not exist on the steel material surface. Thereby, the internal defect detection part after evacuation can be easily brought close to the steel surface without bringing the internal defect detection part and the convex defect into contact with each other. As a result, the internal defect detection unit can be saved and restored without trouble, and the internal defect detection unit can continue the internal defect detection process as much as possible while preventing damage to the internal defect detection unit. It can be carried out.

  In the above-described embodiment, the laser-type convex defect detector 3 is arranged after the mechanical convex defect detector 2, and the surface defect detector 4 is arranged after the convex defect detector 3. However, the arrangement order of the convex defect detectors 2 and 3 and the surface defect detector 4 along the conveying direction of the steel material 15 is not limited to this, taking into account the installation space or detection capability of each detector, The order may be as desired. For example, as shown in FIG. 4, a surface defect detection unit 4 is disposed downstream of the laser-type convex defect detection unit 3 along the conveyance direction of the steel material 15, and a mechanical type is disposed downstream of the surface defect detection unit 4. The convex defect detector 2 may be arranged. Alternatively, the surface defect detection unit 4 may be arranged in front of the two convex defect detection units 2 and 3, and the laser type convex defect detection unit 3 is replaced with the mechanical type convex defect detection unit 2 and the surface defect detection unit 4. It may be arranged in the subsequent stage or other arrangement order.

  Moreover, in embodiment mentioned above, although the wire 2a of the convex defect detection part 2 was stretched by the predetermined | prescribed height from the surface of the steel material 15, it is not restricted to this, The convex produced on the surface of the steel material 15 is carried out. The height of the wire 2a may be changeable according to the height of the defect. For example, as shown in FIG. 4, the convex defect detection unit 2 may be provided with a vertical movement mechanism or the like (not shown) so that the convex defect detection unit 2 can move up and down relatively with respect to the steel material 15. In this case, the convex defect detection unit 2 moves upward as shown in FIG. 4 when a convex part such as an excessively high convex defect or a welded part is approaching, for example, as compared with the wire 2a. The height of the wire 2a from the surface of is moderately increased. Accordingly, contact between the excessive convex defect or the convex portion and the wire 2a can be avoided, and damage to the wire 2a due to this contact and further disconnection can be prevented. The convex defect detection unit 2 may move downward and return to the original state before ascending after avoiding the excessive convex defect or convex part.

  When the convex defect detection unit 2 is configured to be movable up and down relatively with respect to the steel material 15, the convex defect detection unit 2 is either the laser-type convex defect detection unit 3 or the surface defect detection unit 4. As shown in FIG. 4, it is desirable to arrange | position in a back | latter stage, and it is desirable to arrange | position in the back | latter stage of the convex defect detection part 3 and the surface defect detection part 4. As shown in FIG. By arranging in this way, even if there are excessive convex defects or convex portions on the surface of the steel material 15 that may cause damage to the wire 2a, these excessive convex defects or convex portions are connected to the wire 2a. Prior to the contact, at least one of the convex defect detection unit 3 and the surface defect detection unit 4 in the previous stage can detect this excessive convex defect or convex part. As a result, the control unit 9 can move the convex defect detection unit 2 up and down at an appropriate timing. As a result, excessive convex defects or convex portions can easily and reliably damage or break the wire 2a due to contact with the wire 2a. Can be prevented.

  Moreover, in embodiment mentioned above, although the convex defect detection parts 2 and 3 and the surface defect detection part 4 were arrange | positioned as a some convex defect detection part which detects the convex defect of the steel material surface, it is not restricted to this. The plurality of convex defect detectors in the present invention only need to detect the convex defects on the surface of the material to be inspected by different defect detection methods. For example, the plurality of convex defect detection units in the present invention may be any two selected from the convex defect detection units 2 and 3 and the surface defect detection unit 4 described above.

  Specifically, the mechanical convex defect detection unit 2 and the laser convex defect detection unit 3 may be combined. In this case, a mechanical convex defect detection unit is provided after the laser convex defect detection unit 3. 2 is preferably arranged, so that an excessive convex defect or convex portion existing on the surface of the steel material 15 can be detected by the laser type convex defect detection unit 3 prior to the mechanical convex defect detection unit 2. . By using this detection result, contact between the wire 2a and an excessive convex defect or convex portion can be avoided, and as a result, damage to the wire 2a can be prevented. Further, the mechanical convex defect detector 2 can compensate for the disadvantage of the laser convex defect detector 3 that the detection capability is lowered due to a subtle change in the optical axis of the laser beam at the time of detection. On the other hand, the laser-type convex defect detection unit 3 can compensate for the disadvantage of the mechanical convex-defect detection unit 2 that the detection capability is reduced due to the wire 2a being bent by its own weight.

  In the mechanical convex defect detector 2, a difference in height occurs between the center portion and the end portion of the wire 2a due to the bending of the wire 2a. As a result, the gap between the center portion of the wire 2a and the material to be inspected becomes excessively small, and disadvantages such as damage to the wire 2a due to contact between the wire 2a and the material to be inspected, and errors in detection capability occur.

  On the other hand, the mechanical convex defect detection unit 2 and the surface defect detection unit 4 may be combined. In this case, it is desirable to arrange the convex defect detection unit 2 at the subsequent stage of the surface defect detection unit 4. As a result, the same operational effects as those of the laser-type convex defect detection unit 3 described above can be obtained. Further, the convex defect detection unit 2 can compensate for the disadvantage of the surface defect detection unit 4 that it is difficult to detect the convex defect with few two-dimensional features described above.

  On the other hand, the laser-type convex defect detection unit 3 and the surface defect detection unit 4 may be combined. In this case, since there is nothing to detect the convex defect in physical contact with the inspection material, the surface of the inspection material The convex defect and the surface defect can be detected without damage to the detection unit. Further, in this combination, the surface defect detection unit 4 compensates for disadvantages at the time of detection by the laser-type convex defect detection unit 3 as in the case of the mechanical convex-defect detection unit 2 described above, and the laser-type convex defect detection unit 4 The defect detection unit 3 can compensate for disadvantages and the like at the time of detection by the surface defect detection unit 4 as in the case of the mechanical convex defect detection unit 2 described above.

  Note that, in the combination of the convex defect detection units described above, one of the plurality of convex defect detection units captures the surface defect detection unit 4, that is, the surface image of the material to be inspected, and the obtained surface image is obtained. It is preferable to detect the convex defect of the material to be inspected. Specifically, a combination of the surface defect detector 4 and the mechanical convex defect detector 2 or a combination of the surface defect detector 4 and the laser convex defect detector 3 is preferable. This is because the surface defect detection unit 4 is less susceptible to the detection performance due to the variation of the material to be inspected than the convex defect detection units 2 and 3. Specifically, since the mechanical convex defect detection unit 2 or the laser convex defect detection unit 3 directly detects the height of the convex defect, the inspection target material such as vibration of the inspection target material is used. It is easily affected by the variation of the material to be inspected in the thickness direction (height direction). On the other hand, the surface defect detection unit 4 detects the height of the convex defect of the material to be inspected based on the surface image of the material to be inspected. Less susceptible to material fluctuations. That is, the surface defect detection unit 4 is suitable as one of the plurality of convex defect detection units in the present invention in order to compensate for the disadvantages of the convex defect detection units 2 and 3 due to the above-described fluctuation of the material to be inspected.

  In the above-described embodiment, the transport distance of the steel material 15 is measured, and the internal defect detection unit 5 is used for retraction or restoration using the transport distance of the convex defect 15a obtained based on the measurement result. Although the operation timing of the moving unit 6 to be moved is controlled, the present invention is not limited to this, and the operation timing of the moving unit 6 may be controlled using the conveyance time of the convex defect 15a.

  For example, the control unit 9 calculates the conveyance speed of the convex defect 15a based on the conveyance distance and the conveyance time of the convex defect 15a measured by the measurement unit 7, and the conveyance speed of the convex defect 15a and the detection position P1. , P2 is used to calculate the time until the convex defect 15a reaches the detection position P2 of the internal defect detection unit 5. The control unit 9 may control the operation timing of the moving unit 6 using the time thus obtained.

  Or you may comprise so that the conveyance speed (= conveyance speed of the convex defect 15a) of the steel material 15 may be measured by the measurement part 7. FIG. Based on the conveyance speed of the convex defect 15a measured by the measurement unit 7 and the distance L1 between the detection positions P1 and P2, the control unit 9 reaches the detection position P2 of the internal defect detection unit 5. Calculate the time until. The control unit 9 may control the operation timing of the moving unit 6 using the time thus obtained.

  Moreover, in embodiment mentioned above, although the strip-shaped steel material 15 was illustrated as an example of to-be-inspected material, not only this but to-be-inspected material may be plate-shaped steel materials, such as a steel plate. And steel materials of shapes other than these may be sufficient. Alternatively, the material to be inspected may be another metal material such as copper or aluminum. That is, the defect detection apparatus 1 may be installed in a production line that produces metal products other than steel products.

  Further, in the above-described embodiment, as an example of the internal defect detector 5 that is brought close to the surface of the inspection material, a leakage magnetic flux type that detects the leakage magnetic flux from the inspection material and detects the internal defect of the inspection material. However, the present invention is not limited to this, and the internal defect detection unit 5 may be other than the leakage magnetic flux type. For example, an ultrasonic wave is oscillated in a material to be inspected and the object is detected based on the echo. It may be of an ultrasonic type that detects an internal defect of the inspection material.

  Moreover, in embodiment mentioned above, although the measurement part 7 calculated | required the conveyance distance of steel materials using the roll which has a predetermined | prescribed radius, it is not restricted to this, The measurement part 7 sets the conveyance speed of a conveyed product. You may measure the conveyance distance of conveyance objects, such as steel materials, based on the measured conveyance speed obtained and measured time.

  Furthermore, in the above-described embodiment, the internal defect detection unit 5 after retraction is detected by the drive control of the moving unit 6 at the timing after the convex defect 15a passes the detection position P2 of the internal defect detection unit 5 at the detection position P2. However, the present invention is not limited to this, and the internal defect detection unit 5 after retraction may be returned to the original detection position P2 by manual operation. In this case, after confirming that the convex defect 15a has passed the detection position P2, the operator operates the input unit 8 to send instruction information for moving the internal defect detection unit 5 to the detection position P2 to the control unit 9. input. Based on this input information, the control unit 9 may control the moving unit 6 so as to move the internal defect detection unit 5 to the detection position P2 at a timing after the convex defect 15a passes the detection position P2.

  In the above-described embodiment, the convex defect detection units 2 and 3 and the surface defect detection unit 4 are combined as a plurality of convex defect detection units. However, the present invention is not limited to this. The defect detection units 2 and 3 and the surface defect detection unit 4 are combined with one or more defect detection units that detect convex defects on the surface of the material to be inspected by a different defect detection method. Alternatively, two or more of the same type of convex defect detection unit may be used.

  Further, the present invention is not limited to the embodiment described above. What was comprised combining each component mentioned above suitably is also contained in this invention. In addition, all other embodiments, examples, operation techniques, and the like made by those skilled in the art based on the above-described embodiments are included in the present invention.

DESCRIPTION OF SYMBOLS 1 Defect detection apparatus 2,3 Convex defect detection part 2a Wire 3a Light emission part 3b Light reception part 4 Surface defect detection part 5 Internal defect detection part 5a Detector 6 Moving part 7 Measurement part 8 Input part 9 Control part 15 Steel material 15a Convex defect P1, P2 detection position

Claims (3)

Close to the surface of the material to be inspected, an internal defect detector for detecting internal defects in the material to be inspected,
Using different defect detection methods, a plurality of convex defect detection units for detecting convex defects on the surface of the inspection object located on the upstream side of conveyance compared to the internal defect detection unit,
A moving unit that moves the internal defect detector in a direction away from the surface of the inspection material or a direction approaching the surface of the inspection material ;
A measurement unit for measuring a conveyance distance of the inspection object;
Detection of the internal defect detection unit from the detection position of the convex defect based on the detection result of the convex defect by at least one of the plurality of convex defect detection units and the measurement result of the transport distance by the measurement unit Grasping the distance to the position and the transport distance from the detection position of the convex defect, and controlling the moving unit during the period in which the transport distance is less than the distance, from the inspection material to the internal defect detection unit And a control unit that controls the moving unit to bring the internal defect detection unit after the retraction closer to the surface of the inspection object during a period in which the transport distance exceeds the distance ,
A defect detection apparatus comprising:   One of the plurality of convex defect detection units is a surface defect detection unit that captures a surface image of the inspection object and detects the convex defect based on the obtained surface image. The defect detection apparatus according to claim 1. When the convex defect is detected by at least one convex defect detection unit among the plurality of convex defect detection units that respectively detect convex defects on the surface of the material to be inspected by different methods, the plurality of convex defects Based on the detection result of the convex defect by at least one of the detection units and the measurement result of the conveyance distance of the inspection material by the measurement unit, the internal defect of the inspection material is detected from the detection position of the convex defect. A direction to grasp the distance to the detection position of the internal defect detection unit and the conveyance distance from the detection position of the convex defect, and away from the surface of the inspection object during the period when the conveyance distance is less than the distance The internal defect detection unit is moved to move the internal defect detection unit from the material to be inspected, and the internal defect detection unit after retraction is moved to the material to be inspected during a period when the transport distance exceeds the distance. On the surface of Is moved to the brute direction, the save method of defect detection apparatus, characterized in that to close the internal defect detection unit on the surface of the test material.

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