JP2004333484A - Magnetic flaw detection method and magnetic flaw detection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To bring a magnetic flaw detection sheet into close contact with a surface of an inspected object to conduct favorably magnetic particle inspection. <P>SOLUTION: A transparent pressure connection body 4 is supported onto a magnetism generating mechanism A formed into a U-shape by a main body 2 and a pair of magnetic poles 3, via an energizing mechanism B provided with a plurality of compression coils 26, a flexible pressing member C and the magnetic flaw detection sheet D sealed with magnetic powder are overlappedly supported in a position to be astride with the paired magnetic poles on an underface side of the pressure connection body 4, the detection sheet D are arranged on the inspected object 1 when detecting a flaw, magnetism is generated in the magnetism generating mechanism A to attract the magnetic poles 3 onto the inspected object 1, and energizing force from the energizing mechanism B caused by attractive force is made to act on the pressing member C and the magnetic flaw detection sheet D to bring the magnetic flaw detection sheet D into close contact with the inspected object. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention provides a sheet-like or bag-like flexible magnetic inspection sheet enclosing a magnetic sensitive body forming a pattern corresponding to a magnetic flux density by applying pressure from a pressure applying means to the magnetic inspection sheet to be inspected. In this contact state, the magnetic flux generated from the test object is captured by the magnetic field generated by the magnetic generating mechanism acting on the test object in the contact state, and the magnetic flux leaking from the test object is captured by the magnetic sensor of the magnetic inspection sheet, based on the pattern created by the magnetic sensor. The present invention relates to a magnetic flaw detection method and a magnetic flaw detection apparatus for performing flaw detection on an object to be inspected.

  As a technique related to the magnetic flaw detection method and the magnetic flaw detection apparatus configured as described above, a magnetic powder (5) together with water and kerosene is placed inside a sealed space of an inspection cassette (10) having a transparent top surface and side surfaces and a thin bottom portion. ) (Magnetic substance of the present invention) is encapsulated as a suspension, and the magnetizing device (1) is magnetized in a state where the suspension is brought into contact with the object (4) to be inspected, thereby inspecting the pattern (pattern) of the magnetic powder. There is one configured to visually detect a target defective portion (for example, refer to Patent Document 1 and refer to the number in the document).

  As a related technique, two transparent sheets (1a) and (1b) each have a large number of small chambers (2), and each of the small chambers (2) is filled with a white dispersion medium in which magnetic powder is dispersed. The magnetized sheet (18) (the magnetic flaw detection sheet of the present invention) is constituted, and as the batch color magnetic particle flaw detection apparatus, provided with a number of springs (20) (the pressure applying means of the present invention) for pressing the magnetized sheet against the flaw-detected body, In some cases, the magnetized sheet is pressed against the flaw-detected body by the spring force (for example, refer to Patent Document 2 and refer to the reference numbers in the literature).

  Further, as a related technique, a white dispersion medium having a large number of small chambers (2) in two transparent sheets (1a) and (1b) and a magnetic powder (3) dispersed in each of the small chambers (2). The magnetized sheet (4) is a magnetized sheet (magnetic flaw detection sheet of the present invention), and has a magnetizer (14) made of a permanent magnet having a U-shaped cross section. A compression coil spring (15) (pressure applying means of the present invention) is attached, and a pressing tool (16) is further attached to the lower end of the compression coil spring (15). (For example, refer to Patent Document 3 and refer to the numbers in the literature).

JP-A-56-40752 JP 2001-21539 A JP-A-2002-90343

  The technique described in Patent Literature 1 shows a basic technique for inspecting a defect of an inspection target without directly contacting a magnetic sensitive substance such as a magnetic powder with the inspection target. No. 3 discloses a technique for inspecting a defect of an inspection object by bringing a magnetic inspection sheet into contact with the inspection object.

  Here, in consideration of the working mode when inspecting the defect to be inspected, when performing an inspection with high accuracy, the magnetic inspection sheet is closely attached to the inspected object so that there is no gap, and This is an operation mode in which magnetism from the generating mechanism acts on the inspection target. In addition, the technique of magnetic flaw detection is often used for the purpose of inspecting a welded portion for a defect to be inspected, and the welded portion has a protruding portion such as a surplus portion.

  Then, considering the technology shown in Patent Documents 2 and 3, Patent Document 2 uses a large number of springs, so that it is possible to apply pressure to a wide surface of the magnetized sheet (magnetically flaw-proof sheet). Since a strong force acts on the protruding part such as the extra part, and a weak force acts on the flat part separated from the extra part, the pressure acting on the magnetized sheet In the case where the distribution tends to be non-uniform and such a large number of springs are provided, there is room for improvement in that the number of parts is increased and the cost is increased. Furthermore, in Patent Document 3, judging from the drawings, since the pressure of one compression coil spring of a magnetizer (magnetic generation mechanism) is applied from a flat pressing tool to a magnetized sheet (magnetic flaw detection sheet), it is disclosed in Patent Document 3. Although the number of parts is reduced as compared with Reference 2, a strong force acts intensively on a protruding portion such as a surplus portion, and there is a room for improvement because the other portion is hardly affected by a pressing force. There is. In other words, none of the techniques disclosed in Patent Documents 2 and 3 makes it possible to bring the magnetic inspection sheet into close contact with the object to be inspected, which has a protruding portion such as a surplus portion.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic flaw detection method and a magnetic flaw detection apparatus capable of closely attaching a magnetic flaw detection sheet to a surface of a test object where a protruding portion exists and performing a good magnetic test. It is in.

The features, functions and effects of the first aspect of the present invention are as follows.
〔Characteristic〕
A pressure is applied from a pressure applying means to a sheet-shaped or bag-shaped flexible magnetic inspection sheet enclosing a magnetic sensitive material that forms a pattern corresponding to the magnetic flux density, and the magnetic inspection sheet is brought into contact with the inspection object. In the contact state, the magnetism generated by the magnetism generating mechanism acts on the object to be inspected, so that the magnetic flux leaking from the object to be inspected is captured by the magnetic body of the magnetic inspection sheet, and the magnetic field of the object to be inspected is determined based on the pattern created by the magnetic body. In the magnetic flaw detection method for performing flaw detection, the pressure applying means includes a biasing mechanism that generates a biasing force from an attraction force in which a magnetic pole of the magnetic generation mechanism is attracted to the inspection target by magnetism, and a deformation of the magnetic flaw detection sheet. And a pressing member that flexibly deforms, and at the time of flaw detection, the magnetic pole is attracted to the inspection object by magnetism generated by a magnetic generation mechanism. The suction force at the time of the suction through the the pressing member and the biasing mechanism lies in to act on the magnetic flaw detection sheet.

[Action / Effect]
According to the above feature, the magnetic flaw detection sheet and the pressing member are arranged on the surface of the object to be inspected in a superimposed state, and the magnetic pole of the magnetic generating mechanism is attracted to the object to be inspected. To generate an urging force, and this urging force acts on the magnetic inspection sheet via the pressing member. In addition, since the pressing member is flexibly deformed in accordance with the deformation of the magnetic inspection sheet, the surface of the magnetic inspection sheet is flat, for example, when the magnetic inspection sheet is set at a protruding portion such as a welded portion. Even if not, it is possible to apply a uniform pressure to the magnetic inspection sheet from the pressing member without using many springs, and if a transparent material is used as the pressing member, the magnetic inspection sheet The pattern of the magnetic sensitive body appearing inside can be observed through the pressing member. In particular, when the urging force from the urging means is applied to the pressing member, since the attraction force of the magnetic generating mechanism is used, the operator does not need to apply the pressing force artificially, and the vertical wall Even when the inspection target is inspected, no labor is imposed on the worker by using the attraction force of the magnetic generating mechanism. As a result, a magnetic flaw detection method was obtained in which the magnetic flaw detection sheet could be satisfactorily adhered to the surface of the test object to perform a magnetic test with high accuracy.

The features, operations and effects of the magnetic flaw detection method according to claim 2 of the present invention are as follows.
〔Characteristic〕
The magnetic flaw detection method according to claim 1, wherein the pressure applying unit includes at least one permanent magnet at a position corresponding to a peripheral area of the magnetic flaw detection sheet, and the permanent magnet is magnetized to the inspection target. The point is that the urging force is generated from the suction force to be sucked.

[Action / Effect]
According to the above feature, since at least one permanent magnet is provided at a position corresponding to the peripheral area of the magnetic flaw detection sheet, in addition to the attracting force due to the magnetism generated from the magnetic poles of the magnetism generating mechanism, the attracting force due to the magnetism generated from the permanent magnet is provided. The force can be applied to the magnetic inspection sheet via the urging mechanism and the pressing member. As a result, for example, even if the entire magnetic inspection sheet cannot be uniformly urged to the inspection target only by the urging force of the magnetic poles of the magnetic generation mechanism, the entire magnetic inspection sheet is pressed against the inspection target and securely contacts the inspection target. As a result, a method of performing a highly accurate inspection in a simple working form was obtained.

The features, functions and effects of the magnetic flaw detection method according to claim 3 of the present invention are as follows.
〔Characteristic〕
3. The magnetic flaw detection method according to claim 1, wherein the magnetic generation is performed such that the transparent pressure-bonded body that receives the urging force from the urging mechanism is movable in a direction to approach and separate from the inspection object. In addition to being supported by a mechanism, the pressing member and the magnetic inspection sheet are supported by being superimposed on the compression body, and at the time of inspection, the magnetic pole is attracted to the inspection object by magnetism generated by a magnetic generation mechanism. Then, the suction force at the time of the suction is applied from the urging mechanism to the pressure-bonding body, and is applied from the pressure-bonding body to the magnetic flaw detection sheet via a pressing member.

[Action / Effect]
According to the above feature, the compression body is supported with respect to the magnetic generation mechanism, and the pressing member and the magnetic inspection sheet are supported on the compression body in a superimposed manner. Just by setting the magnetism generating mechanism and applying magnetism, the urging force from the urging mechanism is transmitted to the crimping body, the pressing member, and the magnetic inspection sheet to bring the magnetic inspection sheet into close contact with the surface of the inspection object. Further, since the compression body is transparent, the pattern of the magnetic sensitive body appearing in the magnetic test sheet can be observed through the pressing member. As a result, a method for performing a highly accurate inspection in a simple working form was obtained.

The features, functions and effects of the magnetic flaw detection method according to claim 4 of the present invention are as follows.
〔Characteristic〕
4. The magnetic flaw detection method according to claim 3, wherein a protrusion is formed on a surface of the pressure-bonding body on a side of the pressing member, and the flaw detection sheet and the pressing member are located at a position facing the concave portion of the inspection target at the time of flaw detection. Is disposed, and in this state, the magnetic pole is attracted to the object to be inspected by the magnetism generated by the magnetism generating mechanism. At this time, the attracting force is applied by the urging mechanism to the projecting portion of the crimping body, the pressing member, the magnetic force. The point is that the magnetic flaw detection sheet is sequentially transmitted to each of the flaw detection sheets and is brought into close contact with the concave portion of the detection target.

[Action / Effect]
According to the above feature, the urging force from the urging mechanism is applied to the pressing member by the protruding portion formed on the pressure-bonding body. By applying pressure to the flaw detection sheet, the magnetic flaw detection sheet can be deformed into a shape along the concave surface and brought into close contact. As a result, a method has been obtained in which a concave portion of an object to be inspected can be inspected with high accuracy.

The features, operations and effects of the magnetic flaw detection method according to claim 5 of the present invention are as follows.
〔Characteristic〕
5. The magnetic flaw detection method according to claim 4, wherein the magnetism generating mechanism is formed by forming a pair of the magnetic poles for applying magnetism to the object to be inspected, and the protrusion of the pressing member is linear in a predetermined direction. And a virtual straight line connecting the pair of magnetic poles and the predetermined direction are set in a posture orthogonal to or parallel to the predetermined direction, and the magnetic field is set in a concave groove of the inspection target at the time of flaw detection. The point is that the flaw detection sheet and the pressing member are arranged, and the biasing force from the biasing mechanism is applied by making the predetermined direction coincide with the flat direction of the concave groove.

[Action / Effect]
According to the above feature, for example, even when inspecting a portion of a fillet weld as a target to be inspected, by setting a predetermined direction of the protrusion of the pressing member so as to be along a direction along a forming direction of the fillet weld, Inspection of the portion of this fillet welding becomes possible. In the case of performing this inspection, in a mode in which the magnetic pole of the magnetic generation mechanism is set at a position straddling the fillet welding, the inspection can be performed by creating magnetic force lines in a direction orthogonal to the direction in which the fillet welding is formed. In the embodiment in which the magnetic pole of the magnetic generating mechanism is set at a position parallel to the fillet welding, the inspection can be performed by creating magnetic force lines in a direction parallel to the direction in which the fillet welding is formed. As a result, a method has been obtained in which inspection can be performed with high accuracy by applying magnetism in a required direction even at the bottom of a groove or a valley.

The features, functions and effects of the magnetic flaw detection method according to claim 6 of the present invention are as follows.
〔Characteristic〕
6. The magnetic inspection method according to claim 1, wherein the magnetic generation mechanism is configured by forming a pair of magnetic poles at both ends of a main body in a parallel posture, and the magnetic inspection sheet is configured to inspect the magnetic inspection sheet. In this state, the direction of the magnetic pole of the magnetism generating mechanism is set to a posture inclined with respect to the surface to be inspected of the object to be inspected, and the flaw detection is performed by applying magnetism.

[Action / Effect]
According to the above feature, the magnetic generation mechanism is displaced to a position away from a position covering the surface of the magnetic inspection sheet by tilting the magnetic generation mechanism with respect to the surface to be inspected, and the magnetic sensing element of the magnetic inspection sheet becomes The created pattern can be observed without being obstructed from a direction perpendicular to the surface to be inspected of the magnetic inspection sheet. As a result, a method was obtained in which the pattern created by the magnetic sensitive body of the magnetic inspection sheet could be reliably observed.

The features, functions and effects of the magnetic flaw detection method according to claim 7 of the present invention are as follows.
〔Characteristic〕
In the magnetic flaw detection method according to claim 2, the magnetic generation mechanism is formed by forming a pair of magnetic poles in a parallel posture at both ends of a main body, and in a state where the magnetic flaw detection sheet is brought into contact with the inspection object, The direction in which the magnetic pole of the magnetic generation mechanism is directed is set to a posture inclined with respect to the surface to be inspected of the object to be inspected, and flaw detection is performed by applying magnetism. On the opposite side, the permanent magnet is disposed.

[Action / Effect]
According to the above feature, the magnetic generation mechanism is displaced to a position away from a position covering the surface of the magnetic inspection sheet by tilting the magnetic generation mechanism with respect to the surface to be inspected, and the magnetic sensing element of the magnetic inspection sheet becomes The created pattern can be observed without being obstructed from a direction perpendicular to the surface to be inspected of the magnetic inspection sheet. As a result, a method was obtained in which the pattern created by the magnetic sensitive body of the magnetic inspection sheet could be reliably observed. In addition, by arranging a permanent magnet on the side opposite to the inclined side of the magnetic generating mechanism, in addition to the magnetic attraction generated from the magnetic poles of the magnetic generating mechanism, the magnetic attraction generated by the permanent magnet can be reduced. Thus, the magnetic inspection sheet can be made to act on the magnetic inspection sheet in a well-balanced manner via the urging mechanism and the pressing member. As a result, for example, even if the entire magnetic inspection sheet cannot be uniformly urged to the inspection target only by the urging force of the magnetic poles of the magnetic generation mechanism, the entire magnetic inspection sheet is pressed against the inspection target and securely contacts the inspection target. As a result, a method of performing a highly accurate inspection in a simple working form was obtained.

The features, functions and effects of the magnetic flaw detection method according to claim 8 of the present invention are as follows.
〔Characteristic〕
8. The magnetic inspection method according to claim 1, wherein the magnetic generation mechanism forms a pair of the magnetic poles for applying magnetism to the object to be inspected, and attaches the magnetic poles to the magnetic inspection sheet. 9. It is arranged at a straddling position, and the flaw detection is performed by magnetism generated by supplying an alternating current to the magnetism generating mechanism.

[Action / Effect]
According to the above feature, for example, it is possible to directly use the current from the commercial power supply, and it is also possible to not include a power supply device. As a result, a method capable of reducing the cost of the power supply system was obtained.

The features, operations and effects of the magnetic flaw detection method according to claim 9 of the present invention are as follows.
〔Characteristic〕
5. The magnetic flaw detection method according to claim 1, wherein the magnetism generating mechanism forms two pairs of magnetic poles for applying magnetism to the object to be inspected, and a virtual straight line connecting each pair of magnetic poles. 6. These magnetic poles are arranged so as to be orthogonal to each other and at a position straddling the magnetic flaw detection sheet, and an alternating current having a phase difference of 90 degrees is supplied to the magnetic generating mechanism to generate the magnetic poles at the respective magnetic poles. The point is that flaw detection is performed by magnetism caused by a rotating magnetic field.

[Action / Effect]
According to the above feature, by applying a rotating magnetic field to the object to be inspected from the four magnetic poles, for example, even when there are a plurality of cracks formed in different directions, the magnetically sensible body is reliably created in the magnetic inspection sheet. It can be observed as a pattern. As a result, a method was obtained in which even defects having different formation directions could be reliably inspected without performing operations such as changing the attitude of the magnetic generator.

The features, operations and effects of the magnetic flaw detection method according to claim 10 of the present invention are as follows.
〔Characteristic〕
The magnetic flaw detection method according to claim 8 or 9, wherein the alternating current supplied to the coil provided in the magnetic generator is set higher than the frequency of the commercial power supply.

[Action / Effect]
According to the above characteristics, when an alternating magnetic field acts on a magnetic body, it is known that the higher the frequency, the stronger the magnetic field acts near the surface (skin effect). Facilitates finding defects near the surface of the object. As a result, a method has been obtained that makes it easier to find a defect near the surface of the object to be inspected.

The features, functions and effects of the magnetic flaw detection method according to claim 11 of the present invention are as follows.
〔Characteristic〕
The magnetic flaw detection method according to any one of claims 1 to 10, wherein a pattern created by the magnetic sensitive body in the magnetic flaw detection sheet is captured as an image and recorded in a recording unit.

[Action / Effect]
According to the above characteristics, the pattern created by the magnetic sensitive body in the magnetic inspection sheet is captured by a camera or the like, recorded on a photographic film, a recording tape, a semiconductor memory, a hard disk, or the like. And the form can be confirmed. As a result, a method was obtained in which not only the presence or absence of a defect but also the position and form of the defect, if any, could be reliably grasped.

The features, operations and effects of the magnetic flaw detector according to claim 12 of the present invention are as follows.
〔Characteristic〕
A sheet-shaped or bag-shaped flexible magnetic inspection sheet enclosing a magnetic sensitive material that forms a pattern corresponding to the magnetic flux density, and the magnetic inspection sheet is brought into contact with the inspection object by applying pressure to the magnetic inspection sheet. A pressure applying means and a magnetic generation mechanism are provided, and the magnetic flux generated from the magnetic generation mechanism acts on the inspection target in a state where the magnetic inspection sheet is in contact with the inspection target, thereby reducing magnetic flux leaking from the inspection target. In a magnetic flaw detector configured to perform flaw detection of an object to be inspected based on a pattern generated by the magnetic flaw detection sheet, the pressure applying means includes a magnetic pole of the magnetic generation mechanism that is magnetized. An urging mechanism for generating an urging force from an attraction force adsorbed on the inspection object, and a pressing unit that flexibly deforms according to the deformation of the magnetic inspection sheet There in that it includes a door.

[Action / Effect]
According to the above feature, the magnetic flaw detection sheet and the pressing member are arranged on the surface of the object to be inspected in a superimposed state, and the magnetic pole of the magnetic generating mechanism is attracted to the object to be inspected. To generate an urging force, and this urging force acts on the magnetic inspection sheet via the pressing member. In addition, since the pressing member is flexibly deformed in accordance with the deformation of the magnetic inspection sheet, the surface of the magnetic inspection sheet is flat, for example, when the magnetic inspection sheet is set at a protruding portion such as a welded portion. Even if not, it becomes possible to apply uniform pressure to the magnetic inspection sheet from the pressing member without using many springs, and if the pressing member uses a transparent material, Can be observed through the pressing member. In particular, when the urging force from the urging means is applied to the pressing member, since the attraction force of the magnetic generating mechanism is used, the operator does not need to apply the pressing force artificially, and the vertical wall Even when the inspection target is inspected, no labor is imposed on the worker by using the attraction force of the magnetic generating mechanism. As a result, a magnetic flaw detector capable of performing high-precision magnetic inspection with the magnetic flaw detection sheet in good contact with the surface of the test object was obtained.

The features, operations and effects of the magnetic flaw detector according to claim 13 of the present invention are as follows.
〔Characteristic〕
13. The magnetic flaw detection apparatus according to claim 12, wherein the pressure applying means includes at least one permanent magnet at a position corresponding to a peripheral area of the magnetic flaw detection sheet, and the permanent magnet is magnetized to the inspection object. The point is that the urging force is generated from the suction force to be sucked.

[Action / Effect]
According to the above feature, since at least one permanent magnet is provided at a position corresponding to the peripheral area of the magnetic flaw detection sheet, in addition to the attracting force due to the magnetism generated from the magnetic poles of the magnetism generating mechanism, the attracting force due to the magnetism generated from the permanent magnet is provided. The force can be applied to the magnetic inspection sheet via the urging mechanism and the pressing member. As a result, for example, even if the entire magnetic inspection sheet cannot be uniformly urged to the inspection target only by the urging force of the magnetic poles of the magnetic generation mechanism, the entire magnetic inspection sheet is pressed against the inspection target and securely contacts the inspection target. As a result, an apparatus capable of performing highly accurate inspection in a simple working form was obtained.

The features, functions and effects of the magnetic flaw detector according to claim 14 of the present invention are as follows.
〔Characteristic〕
14. The magnetic flaw detector according to claim 12, wherein the transparent magnetic pressure-receiving member receiving the urging force from the urging mechanism is movable so as to be movable toward and away from the object to be inspected. In addition to being supported by the mechanism, the pressing member and the magnetic flaw detection sheet are supported by being superposed on the press body.

[Action / Effect]
According to the above feature, the compression body is supported with respect to the magnetic generation mechanism, and the pressing member and the magnetic inspection sheet are supported on the compression body in a superimposed manner. Just by setting the magnetism generating mechanism and applying the magnetism, the urging force from the urging mechanism is transmitted to the crimping body, the pressing member, and the magnetic inspection sheet to bring the magnetic inspection sheet into close contact with the surface of the inspection object. Further, since the compression body is transparent, the pattern of the magnetic sensitive body appearing in the magnetic test sheet can be observed through the pressing member. As a result, a device capable of performing a highly accurate inspection in a simple working form was obtained.

The features, functions and effects of the magnetic flaw detector according to claim 15 of the present invention are as follows.
〔Characteristic〕
15. The magnetic flaw detector according to claim 14, wherein a protrusion is formed on a surface of the crimping body on a side of the pressing member, and the pressing member and the magnetic flaw detection sheet are arranged along the protrusion. It is in.

[Action / Effect]
According to the above feature, since the urging force from the urging mechanism is applied to the pressing member by the protruding portion formed on the crimping body, even when inspecting a concave portion on the surface of the inspection target, the pressing member is By applying pressure to the magnetic inspection sheet, the magnetic inspection sheet can be deformed into a shape along the concave surface and brought into close contact. As a result, a device capable of inspecting the concave portion of the inspection target with high accuracy was obtained.

The features, operations and effects of the magnetic flaw detector according to claim 16 of the present invention are as follows.
〔Characteristic〕
16. The magnetic flaw detector according to claim 15, wherein the magnetic generation mechanism is formed by forming a pair of the magnetic poles for applying magnetism to the object to be inspected, and the protrusion of the pressing member has a straight line in a predetermined direction. And the virtual straight line connecting the pair of magnetic poles and the predetermined direction are set in a posture orthogonal to or parallel to the predetermined direction.

[Action / Effect]
According to the above feature, for example, even when inspecting a portion of a fillet weld as a target to be inspected, by setting a predetermined direction of the protrusion of the pressing member so as to be along a direction along a forming direction of the fillet weld, Inspection of the portion of this fillet welding becomes possible. In the case of performing this inspection, in a mode in which the magnetic pole of the magnetic generating mechanism is set at a position straddling the fillet welding, the inspection can be performed by creating magnetic force lines in a direction orthogonal to the direction in which the fillet welding is formed. In the embodiment in which the magnetic pole of the magnetic generating mechanism is set at a position parallel to the fillet welding, the inspection can be performed by creating magnetic force lines in a direction parallel to the direction in which the fillet welding is formed. As a result, an apparatus capable of inspecting with high accuracy even at the bottom of a groove or a valley was obtained.

The features, operations and effects of the magnetic flaw detector according to claim 17 of the present invention are as follows.
〔Characteristic〕
17. The magnetic inspection apparatus according to claim 12, wherein the magnetic generation mechanism is configured by forming a pair of the magnetic poles at both ends of a main body in a parallel posture, and inspecting the magnetic inspection sheet with the inspection target. The point that the direction of the magnetic pole of the magnetism generating mechanism in the state of being in contact with the object is set to be inclined with respect to the inspection surface of the inspection object.

[Action / Effect]
According to the above feature, the magnetic generation mechanism is displaced from a position covering the surface of the magnetic inspection sheet by tilting the magnetic generation mechanism, and the pattern created by the magnetic sensitive body of the magnetic inspection sheet is covered by the magnetic inspection sheet. Observation can be made without obstruction from a direction perpendicular to the inspection surface. As a result, an apparatus capable of performing an inspection capable of reliably observing the pattern created by the magnetic sensitive body of the magnetic inspection sheet was obtained.

The features, operations and effects of the magnetic flaw detector according to claim 18 of the present invention are as follows.
〔Characteristic〕
14. The magnetic flaw detection apparatus according to claim 13, wherein the magnetic generation mechanism is configured by forming a pair of the magnetic poles in a parallel posture at both ends of a main body, and in a state where the magnetic flaw detection sheet is brought into contact with the inspection object. The direction in which the magnetic poles of the magnetic generating mechanism are directed is set to a posture inclined with respect to the surface to be inspected of the object to be inspected, and the permanent magnet is disposed on the side opposite to the inclined side of the magnetic generating mechanism. It is at the point where it is arranged.

[Action / Effect]
According to the above feature, the magnetic generation mechanism is displaced from a position covering the surface of the magnetic inspection sheet by tilting the magnetic generation mechanism, and the pattern created by the magnetic sensitive body of the magnetic inspection sheet is covered by the magnetic inspection sheet. Observation can be made without obstruction from a direction perpendicular to the inspection surface. As a result, an apparatus capable of performing an inspection capable of reliably observing the pattern created by the magnetic sensitive body of the magnetic inspection sheet was obtained. In addition, by arranging a permanent magnet on the side opposite to the inclined side of the magnetic generating mechanism, in addition to the magnetic attraction generated from the magnetic poles of the magnetic generating mechanism, the magnetic attraction generated by the permanent magnet can be reduced. Thus, the magnetic inspection sheet can be made to act on the magnetic inspection sheet in a well-balanced manner via the urging mechanism and the pressing member. As a result, for example, even if the entire magnetic inspection sheet cannot be uniformly urged to the inspection target only by the urging force of the magnetic poles of the magnetic generation mechanism, the entire magnetic inspection sheet is pressed against the inspection target and securely contacts the inspection target. As a result, an apparatus capable of performing highly accurate inspection in a simple working form was obtained.

The features, operations and effects of the magnetic flaw detector according to claim 19 of the present invention are as follows.
〔Characteristic〕
17. The magnetic inspection apparatus according to claim 12, wherein the magnetic generation mechanism is configured by forming a pair of the magnetic poles at both ends of a main body in a parallel posture, and inspecting the magnetic inspection sheet with the inspection target. In a state in which the magnetic poles of the magnetic generating mechanism are in contact with the object, the direction of the magnetic poles is from 90 degrees perpendicular to the surface to be inspected of the object to be inclined to 20 degrees inclined to the surface to be inspected. In that it can be changed freely within the range of.

[Action / Effect]
According to the above feature, by changing the attitude of the magnetic generator as needed, the space above the surface to be inspected of the magnetic inspection sheet can be opened and the operator can observe the sheet easily. As a result, an apparatus capable of performing an inspection in a favorable working environment was obtained.

The features, operations and effects of the magnetic flaw detector according to claim 20 of the present invention are as follows.
〔Characteristic〕
14. The magnetic flaw detection apparatus according to claim 13, wherein the magnetic generation mechanism is configured by forming a pair of the magnetic poles in a parallel posture at both ends of a main body, and in a state where the magnetic flaw detection sheet is brought into contact with the inspection object. The direction in which the magnetic poles of the magnetism generating mechanism are directed can be freely changed within a range from a posture perpendicular to the surface to be inspected at 90 degrees to a surface inclined at 20 degrees to the surface to be inspected. The permanent magnet is arranged on the side opposite to the inclined side of the magnetic generating mechanism.

[Action / Effect]
According to the above feature, by changing the attitude of the magnetic generator as needed, the space above the surface to be inspected of the magnetic inspection sheet can be opened and the operator can observe the sheet easily. As a result, an apparatus capable of performing an inspection in a favorable working environment was obtained. In addition, by arranging a permanent magnet on the side opposite to the inclined side of the magnetic generating mechanism, in addition to the magnetic attraction generated from the magnetic poles of the magnetic generating mechanism, the magnetic attraction generated by the permanent magnet can be reduced. Thus, the magnetic inspection sheet can be made to act on the magnetic inspection sheet in a well-balanced manner via the urging mechanism and the pressing member. As a result, for example, even if the entire magnetic inspection sheet cannot be uniformly urged to the inspection target only by the urging force of the magnetic poles of the magnetic generation mechanism, the entire magnetic inspection sheet is pressed against the inspection target and securely contacts As a result, an apparatus capable of performing highly accurate inspection in a simple working form was obtained.

The features, operations and effects of the magnetic flaw detector according to claim 21 of the present invention are as follows.
〔Characteristic〕
21. The magnetic flaw detector according to any one of claims 12 to 20, wherein the magnetic generating mechanism forms a pair of the magnetic poles for applying magnetism to the object to be inspected, and supplies an alternating current to the magnetic generating mechanism. It has a power supply unit for supplying.

[Action / Effect]
According to the above feature, for example, it is possible to directly use the current from the commercial power supply, and it is also possible to not include a power supply device. As a result, an apparatus for reducing the cost of the power supply system was obtained.

The features, operations and effects of the magnetic flaw detector according to claim 22 of the present invention are as follows.
〔Characteristic〕
The magnetic flaw detector according to any one of claims 12 to 15, wherein the magnetic generation mechanism forms two pairs of magnetic poles for applying magnetism to the object to be inspected, and a virtual straight line connecting each pair of magnetic poles. Are arranged perpendicular to each other, and at a position straddling the magnetic flaw detection sheet, a power supply unit for supplying an alternating current having a phase difference of 90 degrees to the magnetic generation mechanism is provided. is there.

[Action / Effect]
According to the above feature, by applying a rotating magnetic field to the object to be inspected from the four magnetic poles, for example, even when there are a plurality of cracks formed in different directions, the magnetically sensible body is reliably created in the magnetic inspection sheet. It can be observed as a pattern. As a result, an apparatus capable of reliably inspecting for defects having different formation directions without performing an operation such as changing the attitude of the magnetic generator is obtained.

The features, functions and effects of the magnetic flaw detector according to claim 23 of the present invention are as follows.
〔Characteristic〕
23. The magnetic flaw detector according to claim 21, wherein an alternating current supplied to a coil provided in the magnetic generator is set higher than a frequency of a commercial power supply.

[Action / Effect]
According to the above characteristics, when an alternating magnetic field acts on a magnetic body, it is known that the higher the frequency, the stronger the magnetic field acts near the surface (skin effect). Facilitates finding defects near the surface of the object. As a result, a device that facilitates finding defects near the surface of the object to be inspected was obtained.

The features, operations and effects of the magnetic flaw detector according to claim 24 of the present invention are as follows.
〔Characteristic〕
The magnetic inspection apparatus according to any one of claims 12 to 23, further comprising an illumination mechanism for illuminating the magnetic inspection sheet.

[Action / Effect]
According to the above feature, the pattern formed by the magnetic sensitive body can be observed by illuminating the magnetic flaw detection sheet with the illumination mechanism even at night or in a room where there is no illumination. As a result, an apparatus capable of performing inspection even in a dark environment was obtained.

The features, functions and effects of the magnetic flaw detector according to claim 25 of the present invention are as follows.
〔Characteristic〕
25. The magnetic flaw detector according to claim 24, wherein the illumination mechanism is configured by a light emitting body provided in the magnetic generation mechanism, or is configured by an optical fiber that guides a light beam to a portion of the magnetic generation mechanism. is there.

[Action / Effect]
According to the above feature, the magnetic flaw detection sheet can be illuminated with a light beam from the light emitting body provided in the magnetism generating mechanism or a light beam from the optical fiber. As a result, by illuminating from the magnetism generating mechanism adjacent to the magnetic inspection sheet, it is possible to obtain a device capable of satisfactorily observing the pattern created by the magnetic sensitive body of the magnetic inspection sheet without disposing lamps near the magnetic inspection sheet. Was.

The features, operations and effects of the magnetic flaw detector according to claim 26 of the present invention are as follows.
〔Characteristic〕
26. The magnetic flaw detection apparatus according to claim 12, wherein the magnetic sensitive material enclosed in the magnetic flaw detection sheet is formed by coating a magnetic substance with a fluorescent substance, and illuminates the magnetic flaw detection sheet with ultraviolet light. It has an ultraviolet generating mechanism.

[Action / Effect]
According to the above feature, the fluorescent substance coated on the magnetic powder in the magnetic flaw detection sheet emits light by the ultraviolet ray from the ultraviolet ray generating mechanism, and the pattern created by the magnetic sensitive body of the magnetic flaw detection sheet can be observed even at night or in a room without illumination. As a result, an apparatus capable of performing inspection even in a dark environment was obtained.

The features, operations and effects of the magnetic flaw detector according to claim 27 of the present invention are as follows.
〔Characteristic〕
The magnetic inspection apparatus according to any one of claims 12 to 26, further comprising an imaging mechanism that captures, as an image, a pattern created by the magnetic sensitive body in the magnetic inspection sheet.

[Action / Effect]
According to the above feature, it is also possible to capture the pattern created by the magnetic sensitive body in the magnetic inspection sheet with a camera or the like, and confirm the position or form where the defect exists from the image. As a result, not only is it possible to confirm the presence / absence of a defect, but also when the defect exists, a device capable of surely grasping the position and form of the defect has been constructed.

The features, operations and effects of the magnetic flaw detector according to claim 28 of the present invention are as follows.
〔Characteristic〕
28. The magnetic flaw detector according to claim 27, further comprising recording means for recording an image photographed by the imaging mechanism.

[Action / Effect]
According to the above characteristics, the pattern created by the magnetic sensitive body in the magnetic flaw detection sheet is captured by a camera or the like, and is recorded on a recording means such as a photographic film, a recording tape, a semiconductor memory, a hard disk, or the like. It is also possible to confirm the existing position and form. As a result, not only was it possible to check for the presence or absence of a defect, but also to obtain a device that could reliably ascertain the position and form when a defect was present.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
As shown in FIGS. 1 to 3, a transparent crimping body is provided via a biasing mechanism B with respect to a magnetic generating mechanism A having a U-shape by forming magnetic poles 3 at both ends of a main body 2. 4 is supported, and the pressing member C and the magnetic inspection sheet D are supported on the pressure-bonding body 4 in a superimposed state, thereby forming a portable magnetic inspection apparatus.

  The above configuration is a typical configuration for realizing the magnetic flaw detection method and the magnetic flaw detection apparatus of the present invention. In this magnetic flaw detection method, a magnetic substance typified by iron is the inspection object 1. Specifically, when inspecting an excess portion 1A of a welded portion of an iron plate material or a defect 1C (scratch such as a crack) of a curved surface portion of an iron pipe, an operator operates the magnetic flaw detector with one hand. Thus, this inspection is realized. It is assumed that the surplus portion 1A has a general form having a width of about 10 mm and a height of about 4 mm from the object 1 to be inspected.

  As shown in FIG. 5, the magnetism generating mechanism A functions as an electromagnet by winding a coil 5 of a good conductor such as a copper alloy around a main body 2 made of a magnetic material. Is provided with a cable 7 for supplying a current from a power supply unit 6 to the coil 5, and a power switch 8, a CCD camera 9 as an imaging mechanism, a photographing switch 10, and a light emitting diode (light emitting body) ) Is provided.

  Although FIG. 1 shows a lighting mechanism 11 composed of a light emitting diode, a fluorescent lamp or a halogen lamp can be used as the lighting mechanism 11. For example, a power supply unit 6 or a light source arranged near this unit can be used. It is also possible to configure the illumination mechanism 11 with an optical fiber that guides a light beam to the portion of the magnetic generation mechanism A. In the case where an optical fiber is used as the illumination mechanism 11, lamps are not provided in the vicinity of the magnetic generation mechanism A, and a power cable does not need to be formed. It will be.

  Further, the power switch 8 is arranged at a position where the operator can press and operate with the fingertip when the operator grips and operates the main body 2. The camera 9 is configured to photograph a pattern of magnetic particles (see FIG. 6) on the magnetic test sheet D, and the photographing switch 10 can be operated when the camera 9 captures an image. Are located in The illuminating mechanism 11 is arranged at a position for illuminating the magnetic flaw detection sheet D by passing a light beam through the pressure bonding plate 4.

  The power supply unit 6 includes an inverter circuit (not shown) so as to increase the frequency of a current from a commercial power supply (approximately 180 Hz / 240 Hz is an upper limit) and supply the current to the coil. An AC current is supplied to the illumination mechanism 11 and a current is supplied to the lighting mechanism 11 simultaneously with the supply of the AC current. The reason for increasing the frequency of the current is that when an alternating magnetic field acts on a magnetic material, it is known that the higher the frequency, the stronger the magnetic field acts near the surface (skin effect). This is to make it easy to find a defect near the surface of the inspection target 1 by using the method.

  Further, a monitor 12 for displaying an image captured by the camera 9 and a recording device 13 (an example of a recording unit) including a semiconductor memory and a hard disk for storing the image captured by the camera 9 are provided. In such a case, a photographing system is configured to photograph with the camera 9, display the image on the monitor 12, and store the image in the recording device 13.

  As long as the power supply unit 6 supplies a current having a frequency in the range of 240 Hz from the frequency of the commercial power supply at the frequency of the commercial power supply, there is no practical inconvenience, and the supplied voltage is 500 V or less. Is desirable. Further, the camera 9 may be a still camera for photographing a still image or a movie camera for photographing a moving image.

  As shown in FIGS. 1 to 3, a transparent acrylic resin support 20 is disposed on the base end side of the pair of magnetic poles 3, and the support 20 is provided with a metal bracket 21 and a support 20. And is fixed by a screw 22 screwed into. The pressure-sensitive adhesive member 4 made of transparent acrylic resin and having a plate shape is disposed on the end of the magnetic pole 3 via the urging mechanism B with respect to the support member 20, and a transparent surface is provided on the lower surface side of the pressure-sensitive member 4. The pressing member C, which deforms flexibly, and the magnetic flaw detection sheet D are supported in an overlapping state. The support 20 can be made of a metal. However, when a metal is used, an induced current may be generated in the metal due to the action of an AC magnetic field generated by the magnetic generating mechanism A to generate heat. In order to avoid this heat generation and to reduce the weight and improve the visibility, a transparent acrylic resin is used.

  The crimping body 4 is supported by the urging mechanism B so as to be movable along the direction in which the magnetic pole 3 is formed (the vertical direction in FIGS. 1 and 2). As shown in FIG. The distance S is set between the virtual straight line connecting the magnetic pole 3 and the bottom surface of the magnetic inspection sheet D. Incidentally, the urging mechanism B, the pressure-bonding body 4 and the pressing member C constitute a pressure applying means.

  In this magnetic inspection apparatus, by removing the screw 22, the supporting mechanism 20 and the urging mechanism B, the press body 4, the pressing member C supported by the press body 4, and the magnetic inspection sheet D are each generated by magnetism. It is configured to be separable from the mechanism A, and by performing this separation, magnetism is applied when performing an inspection in a form in which magnetic particles are sprayed on the inspection target 1 as a conventional magnetic particle flaw detection method. It can also be used as a means. Further, in order to more easily remove the support 20 from the magnetism generating mechanism A, it is conceivable to use a thumb screw instead of the screw 22.

  The biasing mechanism B includes four through holes formed in the support body 20, rods 25 inserted into the four through holes formed in the crimping body 4, and a compression coil spring 26 externally fitted to each rod 25. In the non-use state shown in FIG. 3, the crimped body 4 is supported by the four rods 25 in a suspended state. The urging mechanism B is not limited to the compression coil spring 26, but may be a rubber that obtains an urging force by being elastically deformed, or a gas spring that utilizes gas pressure.

  The pressing member C is formed by mixing polyvinyl alcohol and borax into a bag 30 in which a polyethylene film or a polyvinyl film having a film thickness of about 0.1 to 0.5 mm is formed into a bag shape as a flexible and transparent resin film. Using a transparent gel-like (slime-like) substance 31 (may be water) or a substance obtained by encapsulating a gel-like substance obtained by copolymerizing polyethylene and styrene with oil, or using a bag 30 The gelled material is directly attached without being applied, and is configured so as to be transparent and flexible as a whole. Even when the magnetic test sheet D is in a deformed state, the pressure applied from the pressure-bonding body 4 is reduced. It functions to act on the magnetic test sheet D with a uniform pressure.

  As shown in FIG. 6, the magnetic flaw detection sheet D is formed by laminating an upper surface material 35 made of a flexible and transparent resin film and a lower surface material 36 made of a flexible resin film. A space 37 having a gap d of about 20 to 30 μm is formed by interposing a spacer 37 formed by arranging fibers in a mesh shape between each other. The magnetic powder 38 (an example of a magnetic sensitive material) having a particle size of about 0.1 μm or more and sufficiently smaller than the gap value (about 20 to 30 μm), and a fluid substance 39 such as water or kerosene as a dispersion medium. (May be a gas), and has a hermetically sealed structure in which the outer peripheral portions of the front surface material 35 and the back surface material 36 are joined using a heat welding technique or an adhesive.

  More specifically, a film thickness of the surface material 35 and the back surface material 36 of about 0.02 to 0.5 mm is used, and it is essential that the surface material 35 of the container is transparent. A slightly colored material may be used, and the backing material 136 does not need to be transparent, and a colored resin may be used. Polyethylene, polyvinyl, or PET (polyethylene terephthalate) resin can be used as the front surface material 35 and the back surface material 36, and a soft magnetic austenitic stainless steel foil is used as the back surface material 36 instead of the resin film. Is also possible. Further, as the material of the magnetic powder 38, not only iron and nickel but also magnetite and gamma-hectite can be used.

  Further, as the spacer 37, a particle having the same particle size as the gap d may be used in a form of being dispersed between the front surface member 35 and the back surface member 36, or may be used between the front surface member 35 and the back surface member 36. It is also conceivable to use a plurality of columnar members that can form the gap d.

  When supporting the pressing member C and the magnetic inspection sheet D with respect to the press-bonding body 4, the pressing member C and the magnetic inspection sheet D are overlapped on the bottom side of the pressing body 4, and the end of the magnetic inspection sheet D is The part is pulled up to the upper surface of the crimping body 4, and in a state where an appropriate tension is applied to the magnetic test sheet D, the end of the magnetic test sheet D is press-fitted with the fixing plate 40 and fixed with the screw 41. I have.

  In this magnetic flaw detector, the inspection target 1 is assumed to be a welded portion of a steel plate constituting a tank for storing oil or the like, or a welded portion of a steel plate constituting a bridge or the like. The operation is performed as described below. For example, when flaw detection is to be performed on a portion 1A of a welded portion, as shown in FIG. 3, the magnetic pole 3 is arranged at a position straddling the portion of the surplus 1A, and a position that covers a portion where flaw detection is to be performed. By operating the power switch 8 in a state where the magnetic inspection sheet D is disposed on the coil 5, the current from the power supply unit 6 is supplied to the coil 5, and the coil 5 generates magnetism and the magnetic pole 3 is covered. Adsorb to inspection object 1. When the magnetic pole 3 is thus attracted to the inspection target 1, the distance S (see FIG. 3) between the virtual straight line connecting the pair of magnetic poles 3 and the bottom surface of the magnetic inspection sheet D as shown in FIG. The magnetic pole 3 moves relative to the crimping body 4 by an amount corresponding to the pressure of the compression coil spring 26 of the urging mechanism B, and the urging force from the compression coil spring 26 is applied to the crimping body 4. Further, the pressing force from the pressure-bonding body 4 is applied from the pressing member C to the magnetic inspection sheet D, and the magnetic inspection sheet D is brought into close contact with the inspection target 1.

  In this close contact state, even if there is an extra bank 1A in the welded portion, the magnetic inspection sheet D is deformed into a shape along the portion of the extra bank 1A, and the pressing member C is deformed to follow this deformation, and 4, since the pressure is applied to the magnetic inspection sheet D as a uniform pressure, the entire surface of the bottom surface (outer surface of the back surface member 36) of the magnetic inspection sheet C is closely adhered to the upper surface of the inspection object 1 without any gap. It becomes. Then, a magnetic circuit is formed between the pair of magnetic poles 3 and the inspection target 1 in a state where the magnetic inspection sheet D is in close contact with the inspection target 1 in this manner, and the respective magnetic poles 3 are connected to each other. If the magnetic field lines are formed in the direction and the defect 1C is present at the portion of the extra bank 1A, the magnetic flux leaks at the defect 1C and acts on the magnetic powder 38 of the magnetic inspection sheet D. A pattern in which the magnetic particles 38 form a line along the direction is created, and the defect 1C can be grasped visually or, when photographed by the camera 9, from the photographed image. If the direction of the magnetic pole 3 of the magnetism generating mechanism A is set to, for example, an attitude perpendicular to the surface to be inspected of the inspection object 1 as shown in FIG. Since the inspection can be performed, a clearer pattern of the magnetic powder 38 can be obtained.

  As described above, in the first embodiment, the magnetic test sheet D formed in a flexible sheet shape, the pressing member C configured to be flexible and capable of transmitting pressure, and the crimping body 4 that is hardly deformed. Are integrated and supported in such a state that the urging force from the urging mechanism B can act on the magnetism generating mechanism A. Therefore, when inspecting the inspection target 1, the operator can use the magnetic inspection sheet. It is not necessary to perform the operation of setting D artificially, which improves the workability. In addition, when performing the flaw detection, the magnetic pole 3 is attracted to the inspection target 1 by the magnetic force only by operating the power switch 8. By this suction, the urging force from the urging mechanism B is applied to the crimping body 4, and the pressing member C and the magnetic test sheet D are sandwiched between the crimping body 4 and the inspection object 1 to be inspected. Magnetic test sheet D for subject 1 During without close contact so, with each other to those capable of performing inspection with high accuracy at high sensitivity.

  Since this magnetic flaw detector is relatively small and is configured to be easy to handle, it can be easily operated even on an inspection object having a vertical wall shape or a ceiling wall shape. In particular, since the illumination device 11 is provided for the magnetic generation mechanism A, the pattern created by the magnetic sensitive body of the magnetic inspection sheet D can be clearly observed even at night or indoors where there is no illumination.

  In the magnetic flaw detection apparatus of the first embodiment, even if the entire magnetic flaw detection sheet D cannot be uniformly urged toward the inspection target 1 only by the urging force of the magnetic pole of the magnetic generating mechanism, the magnetic flaw detection sheet D At least one permanent magnet is arranged at a position corresponding to the peripheral area of the magnetic flaw detection sheet D of the pressure applying means, as in a sixth embodiment to be described later, in order to press the whole against the object to be inspected and make sure that the whole is in contact with the object to be inspected. However, the permanent magnet may be configured to generate an urging force from an attraction force attracted to a test object by magnetism. Details of the permanent magnet and the like will be described in detail in the sixth embodiment.

[Second embodiment]
In the second embodiment, those having the same functions as those in the first embodiment are denoted by the same reference numerals and symbols as those in the first embodiment.

  In the second embodiment, the structure of the magnetic generating mechanism A, the structure of the pressure-bonding body 4, the structure in which the pressing member C and the magnetic test sheet D are supported on the pressure-bonding body 4 in an overlapping manner, and the pressing member The structure of C and the magnetic test sheet D is basically the same as that of the first embodiment. As shown in FIGS. 7 and 8, a virtual structure including the main body 2 of the magnetic generation mechanism A and a pair of magnetic poles 3 is used. It is characterized in that the relative angle between the flat surface and the bottom surface of the crimping body 4 is set to an angle θ (about 20 degrees). Although the specific structure is not shown in the figure, the crimping body 4 is movably supported with respect to the magnetic generating mechanism A in a direction perpendicular to the plate surface of the crimping body 4 (vertical direction in FIG. 8). A spring-type urging mechanism B is provided between the magnetism generating mechanism A and the pressure-bonding body 4. Incidentally, also in the second embodiment, the urging mechanism B, the pressure bonding body 4 and the pressing member C constitute a pressure applying means.

  Since the magnetic flaw detector is configured as described above, the pattern generated by the magnetic particles 38 of the magnetic flaw detection sheet D can be observed without being hindered by the magnetic generation mechanism A when performing inspection on the inspection target 1 at the time of inspection. It becomes.

  Further, in the second embodiment, the configuration including the lighting device 11 and the camera 9 shown in the first embodiment, or setting the frequency of the power supply unit 6 higher than the frequency of the commercial power supply, etc. The configuration described in the first embodiment may be arbitrarily used. Further, the angle θ described above is not limited to about 20 degrees, and an angle having a value larger than about 20 degrees may be selected according to the work mode.

[Third embodiment]
In the third embodiment, those having the same functions as those in the first embodiment are denoted by the same reference numerals and symbols as those in the first embodiment.

  In the third embodiment, the structure of the magnetism generating mechanism A, the structure of the crimping body 4, the structure in which the pressing member C and the magnetic flaw detection sheet D are supported on the crimping body 4 in an overlapping manner, and the pressing member The structure of C and the magnetic test sheet D is basically the same as that of the first embodiment. As shown in FIGS. 9 and 10, a virtual structure including a main body 2 of a magnetic generation mechanism A and a pair of magnetic poles 3. The feature is that the relative angle between the flat surface and the bottom surface of the crimping body 4 can be changed.

  That is, a bracket 4A is formed at an end of the crimping body 4, and a support shaft 3A protruding from the magnetic pole 3 is inserted into an elongated hole 4B formed in the bracket 4A, and the center of the support shaft 3A is centered. A lock mechanism (not shown) for determining the swinging posture of the magnetism generating mechanism A is provided, and further, an urging mechanism B including a spring for applying an urging force to the support shaft 3A is provided. With this configuration, the magnetic generation mechanism A can freely adjust the angle θ in the range of 20 degrees to 90 degrees with respect to the crimp body 4, and It is movable in a direction perpendicular to the plane (the longitudinal direction of the long hole 4B, the vertical direction in FIG. 10). Incidentally, also in the third embodiment, the urging mechanism B, the pressure bonding body 4 and the pressing member C constitute a pressure applying means.

  Since the posture of the magnetic generation mechanism A can be set arbitrarily in this manner, not only can the posture of the magnetic generation mechanism A be set to a posture that is easy for the operator to operate during inspection, but also the crimping body By setting the position above 4 to be open, the pattern created by the magnetic particles 38 of the magnetic inspection sheet D can be observed without being obstructed by the magnetic generation mechanism A, as in the second embodiment.

  Also, in the third embodiment, the configuration including the lighting device 11 and the camera 9 shown in the first embodiment, or setting the frequency of the power supply unit 6 higher than the frequency of the commercial power supply, etc. The configuration described in the first embodiment may be arbitrarily used.

[Fourth embodiment]
In the fourth embodiment, components having the same functions as those in the first embodiment are denoted by the same reference numerals and symbols as those in the first embodiment.

  In the fourth embodiment, as shown in FIG. 11 and FIG. 12, the posture along the virtual straight line connecting the pair of magnetic poles 3 with respect to the lower surface of the crimping body 4 (the side facing the magnetic inspection sheet D). A protruding portion 4T that is a straight convex is formed. The structure in which the pressing member C and the magnetic flaw detection sheet D are supported by being superposed on the support 4 and the structure of the pressing member C and the magnetic flaw detection sheet D are basically different from those of the first embodiment. There is basically no change in the structure of the magnetic generation mechanism A. Although the projection 4T is shown as an integral part of the crimping body 4 in the same figure, a structure in which the projection 4T and the crimping body 4 are formed by different members may be used. Incidentally, also in the fourth embodiment, the urging mechanism B, the pressing body 4 and the pressing member C constitute a pressure applying means.

  As shown in FIG. 11, this magnetic flaw detector assumes a fillet weld 1B to be a concave or V-shaped groove (an example of a concave portion) as the inspection object 1, and performs an inspection. In this case, the pair of magnetic poles 3 of the magnetic generator A are arranged in parallel in the direction along the welding direction of the fillet weld 1B (the direction in which the groove-shaped bottom is formed) (connect the tips of the pair of magnetic poles 3). The magnetic pole 3 is attracted to the fillet weld 1B by causing the magnetic pole 3 to be attracted to the fillet weld 1B by making the magnetic field act by matching the direction in which the fillet weld 1B is formed. Is realized.

  As described above, in the present invention, the protrusion 4T is formed on the lower surface of the pressure-bonding body 4, so that the fillet weld 1B of the inspection target 1 and the bottom of the grooved surface can be easily inspected. In particular, since the direction in which the magnetism acts is parallel to the direction in which the fillet welded portion 1B is formed, cracks and the like whose longitudinal direction is oriented in a direction orthogonal to the direction in which the magnetism acts can be detected well. ing.

  Further, in the fourth embodiment, the configuration including the lighting device 11 and the camera 9 shown in the first embodiment, or setting the frequency of the power supply unit 6 higher than the frequency of the commercial power supply, etc. The configuration described in the first embodiment may be arbitrarily used.

[Fifth Embodiment]
In the fifth embodiment, components having the same functions as those in the first embodiment are denoted by the same reference numerals and symbols as those in the first embodiment.

  In the fifth embodiment, as shown in FIG. 13, a linear projection is formed on the lower surface (the side facing the magnetic inspection sheet D) of the crimping body 4 in a direction orthogonal to a virtual straight line connecting the magnetic poles 3 to each other. A protruding portion 4T is formed. The structure in which the pressing member C and the magnetic inspection sheet D are supported by being superposed on the protruding portion 4T, and the structure of the pressing member C and the magnetic inspection sheet D are basically different from those in the first embodiment. There is basically no change in the structure of the magnetic generation mechanism A. However, in the fifth embodiment, the support 20 is supported on the relatively end side of the magnetic pole 3, and the intermediate support 20A is formed on the lower surface of the support 20. The pressing member 4 is formed via the urging mechanism B, and the projection 4T is formed on the lower surface (on the side of the magnetic flaw detection sheet D) of the pressing member 4 as described above. Further, a yoke 3Y made of a magnetic material is formed at the end of the magnetic pole 3 in order to apply magnetism from the magnetic pole 3 to the inspection target 1. Incidentally, also in the fifth embodiment, the urging mechanism B, the pressure bonding body 4 and the pressing member C constitute a pressure applying means.

  In this magnetic flaw detector, a fillet welded portion 1B serving as a concave or V-shaped groove (an example of a concave portion) is assumed as the object 1 to be inspected. A virtual straight line connecting the tips of the pair of magnetic poles 3 in a direction in which the pair of yokes 3Y (magnetic poles 3) of the magnetic generator A are arranged in parallel in a direction orthogonal to the welding direction of the portion 1B (the direction in which the groove-shaped bottom is formed). (In a direction parallel to the fillet welded portion 1B), and magnetism is applied, so that the yoke 3Y is attracted to the surface of the inspection target 1 at a position straddling the fillet welded portion 1B and is formed perpendicular to the fillet welded portion 1B. Inspection in the form of applying magnetism in the direction is realized. In particular, as shown in the figure, even if the member 1X that inhibits the inspection is protruded from the object 1 to be inspected, the inspection can be realized without difficulty by forming the yoke 3Y on the magnetic pole 3. I have to.

  As described above, in the present invention, the protrusion 4T is formed on the lower surface of the pressure-bonding body 4, so that the fillet weld 1B of the inspection target 1 and the bottom of the grooved surface can be easily inspected. In particular, since the direction in which the magnetism acts is orthogonal to the direction in which the fillet weld 1B is formed, cracks and the like whose longitudinal direction is oriented in a direction perpendicular to the direction in which the magnetism acts can be detected well. ing.

  Further, in the fifth embodiment, the configuration including the lighting device 11 and the camera 9 shown in the first embodiment, or setting the frequency of the power supply unit 6 higher than the frequency of the commercial power supply, etc. The configuration described in the first embodiment may be arbitrarily used.

[Sixth Embodiment]
In the sixth embodiment, components having the same functions as those in the first embodiment are denoted by the same reference numerals and symbols as those in the first embodiment.

  In the sixth embodiment, as shown in FIG. 14, the structure of the magnetism generating mechanism A, the structure of the pressure-bonding body 4, and the pressing member C and the magnetic test sheet D are supported on the pressure-bonding body 4 in an overlapping manner. The structure described above, and the structure of the pressing member C and the magnetic inspection sheet D are basically the same as those of the first embodiment, but in the sixth embodiment, the magnetic generating mechanism A The magnetic generating mechanism A is fixed so that the pattern created by the magnetic sensitive body of the magnetic test sheet D can be observed without obstruction from a direction perpendicular to the surface to be inspected of the magnetic test sheet D. The posture of the object 1 to be inspected is set to be inclined with respect to the surface to be inspected. The magnetic generating mechanism A is fixed so that the difference (magnetic pole side gap) between the lowermost part of the magnetic pole 3 and the bottom surface of the magnetic inspection sheet D is about 3 mm.

  In such a magnetic flaw detector, for example, when the inspection is performed with the magnetic flaw detector mounted on the inspection object 1 in a horizontal plane, the center of gravity of the magnetic generation mechanism A is tilted because the magnetic generation mechanism A is inclined. Since the magnetic detection mechanism D is located at a position deviated from the sky above the center of the flaw detection sheet D toward the inclined side of the magnetic generation mechanism A, the entire magnetic flaw detection sheet D is uniformly applied to the inspection target 1 only by the urging force of the magnetic poles 3 of the magnetic generation mechanism A. There is a case where the magnetic test sheet D cannot be brought into contact with the inspection target 1 because it cannot be biased.

  Therefore, the pressure applying means including the pressure-bonding body 4 and the pressing member C includes at least one permanent magnet 50 at a position corresponding to the peripheral area of the magnetic test sheet D. Then, the permanent magnet 50 can generate an attracting force to be attracted to the inspection target 1 by its magnetism. Since the permanent magnet 50 functions to assist the attraction force of the magnetism generating mechanism A from the magnetic pole 3, it is possible to press the entire magnetic flaw detection sheet D against the object 1 to be inspected and securely contact the same. .

  In the sixth embodiment, the configuration including the lighting device 11 and the camera 9 shown in the first embodiment, or setting the frequency of the power supply unit 6 higher than the frequency of the commercial power supply, or the like, The configuration described in the embodiment may be arbitrarily used. Further, as shown in the third embodiment, the inclination posture of the magnetic generating mechanism A is changed from a posture orthogonal to the inspection surface of the inspection target 1 at 90 degrees to 20 degrees with respect to the inspection surface. It can also be configured to be freely changeable within a range up to the inclined posture.

  Next, the optimal arrangement of the permanent magnet 50 on the pressure applying means will be described with reference to FIGS.

  The permanent magnet 50 is attached to the crimping body 4 of the pressure applying means. Specifically, as shown in FIG. 16, the permanent magnet 50 mounted on the mounting tool 51 having a U-shaped cross section is held and fixed to the peripheral region of the crimping body 4 with bolts b1 to b6. . At this time, the difference (permanent magnet side gap) between the bottom surface of the permanent magnet 50 and the bottom surface of the magnetic inspection sheet D is set to about 1 to 4 mm. The gap on the permanent magnet side can be appropriately adjusted by interposing, for example, an aluminum spacer 52 between the permanent magnet 50 and the mounting tool 51. Further, the permanent magnet 50 has a magnetic force sufficient to assist the magnetic attraction force from the magnetic pole 3 of the magnetic generating mechanism A, but does not affect the measurement of magnetic flaw detection. This is because the permanent magnets 50 are spaced apart from the magnetic inspection sheet D so as not to affect the magnetic particles 38 in the magnetic inspection sheet D, and the spacers 37 provided in the magnetic inspection sheet D This restricts excessive movement of the magnetic powder 38.

  In this specification, for convenience, the side on which the magnetic generating mechanism A is inclined is defined as the rear side, and the opposite side is defined as the front side. Then, in the magnetic flaw detector according to the sixth embodiment, as shown in FIG. 15, the permanent magnets 50 can be held and fixed at three places before and after the crimping body 4 by bolts b1 to b6. The bolts mounted on the front side are b1, b2, b3, and the bolts mounted on the rear side are b4, b5, b6.

Table 1 below shows the results of the evaluation of the adsorption stability of the magnetic flaw detector based on the difference in the mounting position of the permanent magnet 50.

  Here, the permanent magnet 50 used for the adsorption stability evaluation is a neodymium magnet having a square cross section of 10 mm on a side and a thickness of 8 mm. The test piece used for the stability evaluation is a standard test piece A1-15 / 100 (linear type) for magnetic particle flaw detection specified in Japanese Industrial Standard JIS G 0565. The numbers described in the columns b1 to b6 are the numbers of the permanent magnets 50 attached to the bolt positions. In the column of the adsorption stability, も の: Good adsorption, Δ: Adsorbed at first but then insufficiently adsorbed, or permanent magnet 50 was too strong to remove afterwards And ×: each of which shows that the front side is lifted due to insufficient adsorption.

  According to the results in Table 1 above, evaluation No. Conditions 3 and 4 showed good adsorption stability. That is, in this magnetic flaw detector, the permanent magnet 50 is not disposed on the rear side, and three permanent magnets 50 are provided only on the center bolt b2 on the front side, or the permanent magnets 50 are respectively provided on the bolts b1, b2, and b3. It has become clear that it is preferable to use one in which the permanent magnets 50 are installed one by one.

[Another embodiment]
The present invention can be configured, for example, as follows, in addition to the above-described embodiment. (In this alternative embodiment, components having the same functions as those of the above-described embodiment are denoted by the same reference numerals as those of the embodiment.) , With a sign).

(A) As shown in FIG. 17, two "U" -shaped magnetism generating portions each having a pair of magnetic poles 3 formed on the main body portion 2 are used, and the magnetic poles 3 of each magnetism generating portion have a cross-shaped line. The magnetism generating mechanism A is configured by arranging them so as to be positioned above, and a current from a power supply 56 is supplied to one coil 5 in a state where a phase difference of 90 degrees is set by a phase shifter 55. Thus, a rotating magnetic field is generated in each magnetic pole 3. Although not shown in the figure, the structure of the pressure-bonding body 4 and the structure in which the pressing member C and the magnetic inspection sheet D are supported by being superposed on the pressure-bonding body 4 are basically the same as in the first embodiment. There is no change.

  With such a configuration, for example, even if the direction in which cracks are formed is different, the pattern can be reliably observed as a pattern created by the magnetic sensitive body in the magnetic inspection sheet D, and operations such as changing the attitude of the magnetic generator A can be performed. Even without performing this, it is possible to reliably inspect even defects having different formation directions.

(B) As the magnetic sensitive body, a magnetic powder 38 coated with a fluorescent substance is used, and as the illumination mechanism 13, an ultraviolet light source (ultraviolet light generating mechanism) is used. Although this configuration is not different from that of the first embodiment and is not shown in the drawings, the fluorescent material coated on the magnetic powder 38 emits light due to the light from the ultraviolet light source when performing an inspection. Also, even at night or indoors where there is no illumination, the pattern created by the magnetic sensitive body of the magnetic test sheet D can be observed by the emission of the fluorescent substance.

(C) On the surface of the compression-bonding body 4, lines are formed on a scale capable of measuring the size of a pattern appearing on the magnetic inspection sheet D by a printing technique or the like, or in a vertical or horizontal mesh shape. By forming the scales and lines in this way, the size of the defect and the direction in which the defect is formed can be easily specified.

(D) A lens is detachably attached to the surface of the crimping body 4. By providing the lens in this manner, it is possible to magnify and observe the pattern appearing on the magnetic flaw detection sheet D, so that the detailed form of the defect can be properly grasped. In particular, by using a Fresnel lens as a lens, it is possible to suppress an increase in size.

1 is a perspective view of a magnetic flaw detector according to a first embodiment. FIG. 2 is an exploded perspective view of the magnetic flaw detector according to the first embodiment. Partial cutaway side view of the magnetic flaw detector of the first embodiment. Partially cutaway side view of the magnetic flaw detector according to the first embodiment during flaw detection. FIG. 2 is a block circuit diagram showing a control system of the magnetic flaw detector according to the first embodiment. FIG. 4 is a longitudinal sectional view and a transverse sectional view of the magnetic inspection sheet according to the first embodiment. Perspective view of a magnetic flaw detector according to a second embodiment. Side view of the magnetic flaw detector of the second embodiment Perspective view of a magnetic flaw detector according to a third embodiment. Side view of the magnetic flaw detector of the third embodiment Sectional view of a magnetic flaw detector according to a fourth embodiment. The perspective view which shows the shape of the pressure bonding body of 4th Embodiment. Partial cutaway side view of a magnetic flaw detector according to a fifth embodiment. Perspective view of a magnetic flaw detector according to a sixth embodiment. Top view of a magnetic flaw detector according to a sixth embodiment Partial sectional view of the magnetic flaw detector shown in FIG. Schematic diagram showing the principle of a magnetic generation mechanism in another embodiment (a).

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Inspection object 3 Magnetic pole 4 Crimping body 4T Projecting part 6 Power supply part 9 Imaging mechanism 11 Illumination mechanism 13 Recording means 38 Magnetic sensitive body 50 Permanent magnet A Magnetic generating mechanism B Energizing mechanism C Pressing member D Magnetic flaw detection sheet

Claims (28)

A pressure is applied from a pressure applying means to a sheet-shaped or bag-shaped flexible magnetic inspection sheet enclosing a magnetic sensitive material that forms a pattern corresponding to the magnetic flux density, and the magnetic inspection sheet is brought into contact with the inspection object. In the contact state, the magnetism generated by the magnetism generating mechanism acts on the object to be inspected, so that the magnetic flux leaking from the object to be inspected is captured by the magnetic body of the magnetic inspection sheet, and the magnetic field of the object to be inspected is determined based on the pattern created by the magnetic body. A magnetic flaw detection method for flaw detection,
The pressure applying means includes an urging mechanism that generates an urging force from an attraction force in which a magnetic pole of the magnetic generation mechanism is attracted to the inspection target by magnetism, and a pressing member that flexibly deforms according to the deformation of the magnetic inspection sheet. Prepared,
At the time of flaw detection, a magnetic flaw detection method in which the magnetic pole is attracted to the object to be inspected by magnetism generated by a magnetism generating mechanism, and the attraction force at the time of the suction is applied to the magnetic flaw detection sheet via the urging mechanism and the pressing member. .   The pressure applying means includes at least one permanent magnet at a position corresponding to a peripheral area of the magnetic flaw detection sheet, and the permanent magnet generates an urging force from an attraction force attracted to the inspection object by magnetism. Item 6. The magnetic inspection method according to Item 1.   A transparent crimping body receiving the urging force from the urging mechanism is supported by the magnetic generating mechanism so as to be movable in a direction approaching and separating from the object to be inspected, and the crimping body is A pressing member and the magnetic flaw detection sheet are superposed and supported, and at the time of flaw detection, the magnetic pole is attracted to the object to be inspected by magnetism generated by a magnetism generating mechanism. The magnetic flaw detection method according to claim 1, wherein the magnetic flaw detection sheet is applied to the magnetic flaw detection sheet via a pressing member.   A protrusion is formed on a surface of the pressure-bonding body on the side of the pressing member, and the magnetic test sheet and the pressing member are arranged at a position facing the concave portion of the inspection object at the time of flaw detection. The magnetic pole is attracted to the object to be inspected by the magnetism generated in the step, and at this time, the attracting force is sequentially transmitted from the urging mechanism to the protrusion, the pressing member, and the magnetic flaw detection sheet of the crimping body. The magnetic inspection method according to claim 3, wherein the magnetic inspection sheet is brought into close contact with the concave portion of the detection target.   The magnetism generating mechanism is formed by forming a pair of the magnetic poles for applying magnetism to the object to be inspected, and the protrusion of the pressing member is formed in a convex shape that is linear in a predetermined direction. A virtual straight line connecting the magnetic poles and the predetermined direction are set to be orthogonal or parallel, and at the time of flaw detection, the magnetic flaw detection sheet and the pressing member are arranged in the concave groove of the inspection object, and the concave shape is formed. 5. The magnetic flaw detection method according to claim 4, wherein the biasing force from the biasing mechanism is applied by making the predetermined direction coincide with the flat direction of the groove.   The magnetic generating mechanism is formed by forming a pair of magnetic poles in a parallel posture at both ends of the main body, and in a state where the magnetic flaw detection sheet is in contact with the object to be inspected, a direction toward the magnetic pole of the magnetic generating mechanism, The magnetic flaw detection method according to any one of claims 1 to 5, wherein flaw detection is performed by setting a posture inclined with respect to the inspection target surface of the inspection target and applying magnetism.   The magnetic generating mechanism is formed by forming a pair of magnetic poles in a parallel posture at both ends of the main body, and in a state where the magnetic flaw detection sheet is in contact with the object to be inspected, a direction toward the magnetic pole of the magnetic generating mechanism, The flaw detection is performed by setting a posture inclined with respect to the surface to be inspected of the object to be inspected and applying magnetism, and the permanent magnet is arranged on a side opposite to a side of the magnetism generating mechanism that is inclined. 3. The magnetic flaw detection method according to 2.   The magnetic generation mechanism forms a pair of the magnetic poles for applying magnetism to the object to be inspected, arranges the magnetic poles at a position across the magnetic flaw detection sheet, and supplies an alternating current to the magnetic generation mechanism. The magnetic flaw detection method according to any one of claims 1 to 7, wherein flaw detection is performed by generated magnetism.   The magnetism generating mechanism forms two pairs of magnetic poles for applying magnetism to the object to be inspected, such that virtual straight lines connecting each pair of magnetic poles are orthogonal, and these are positioned at positions straddling the magnetic inspection sheet. The flaw detection is performed by arranging magnetic poles and supplying alternating current having a phase difference of 90 degrees to the magnetism generating mechanism by magnetism caused by a rotating magnetic field generated at each magnetic pole. 2. The magnetic flaw detection method according to claim 1.   The magnetic flaw detection method according to claim 8, wherein an alternating current supplied to a coil provided in the magnetic generator is set higher than a frequency of a commercial power supply.   The magnetic flaw detection method according to any one of claims 1 to 10, wherein a pattern created by the magnetic sensitive body in the magnetic flaw detection sheet is captured as an image and recorded in a recording unit. A sheet-shaped or bag-shaped flexible magnetic inspection sheet enclosing a magnetic sensitive material that forms a pattern corresponding to the magnetic flux density, and the magnetic inspection sheet is brought into contact with the inspection object by applying pressure to the magnetic inspection sheet. A pressure applying means and a magnetic generation mechanism are provided, and the magnetic flux generated from the magnetic generation mechanism acts on the inspection target in a state where the magnetic inspection sheet is in contact with the inspection target, thereby reducing magnetic flux leaking from the inspection target. A magnetic flaw detector which is configured to detect a flaw of an object to be inspected based on a pattern created by the magnetic fever, which is captured by a magnetic body of the magnetic flaw detection sheet,
The pressure applying means includes an urging mechanism that generates an urging force from an attraction force in which a magnetic pole of the magnetic generation mechanism is attracted to the inspection target by magnetism, and a pressing member that flexibly deforms according to the deformation of the magnetic inspection sheet. Magnetic flaw detector provided.   The pressure applying means includes at least one permanent magnet at a position corresponding to a peripheral area of the magnetic flaw detection sheet, and the permanent magnet generates an urging force from an attraction force attracted to the inspection target by magnetism. Item 13. A magnetic flaw detector according to Item 12.   A transparent crimping body receiving the urging force from the urging mechanism is supported by the magnetic generating mechanism so as to be movable in a direction approaching and separating from the object to be inspected, and the crimping body is 14. The magnetic flaw detector according to claim 12, wherein the pressing member and the magnetic flaw detection sheet are overlapped and supported.   The magnetic flaw detector according to claim 14, wherein a protrusion is formed on a surface of the crimping body on the side of the pressing member, and the pressing member and the magnetic flaw detection sheet are arranged along the protrusion.   The magnetism generating mechanism is formed by forming a pair of the magnetic poles for applying magnetism to the object to be inspected, and the protrusion of the pressing member is formed in a convex shape that is linear in a predetermined direction. 16. The magnetic flaw detector according to claim 15, wherein a virtual straight line connecting the magnetic poles and the predetermined direction are set to be orthogonal or parallel.   The magnetic generating mechanism is formed by forming a pair of the magnetic poles in a parallel posture at both ends of the main body, and in a state where the magnetic flaw detection sheet is in contact with the inspection target, the direction of the magnetic pole of the magnetic generating mechanism is changed. The magnetic flaw detector according to any one of claims 12 to 16, wherein the posture is set to be inclined with respect to the surface to be inspected of the object to be inspected.   The magnetic generation mechanism is formed by forming a pair of the magnetic poles in a parallel posture at both ends of the main body, and in a state where the magnetic flaw detection sheet is in contact with the inspection object, the direction of the magnetic poles of the magnetic generation mechanism is changed. 14. The magnetic inspection apparatus according to claim 13, wherein the permanent magnet is set to a posture inclined with respect to a surface to be inspected of the object to be inspected, and the permanent magnet is arranged on a side opposite to an inclined side of the magnetic generation mechanism. apparatus.   The magnetic generating mechanism is formed by forming a pair of the magnetic poles in a parallel posture at both ends of the main body, and in a state where the magnetic flaw detection sheet is in contact with the inspection target, the direction of the magnetic pole of the magnetic generating mechanism is changed. 17. The apparatus according to claim 12, wherein the posture of the object to be inspected can be changed within a range from a posture perpendicular to the surface to be inspected at 90 degrees to a posture inclined to 20 degrees with respect to the surface to be inspected. 2. The magnetic flaw detector according to claim 1.   The magnetic generating mechanism is formed by forming a pair of the magnetic poles in a parallel posture at both ends of the main body, and in a state where the magnetic flaw detection sheet is in contact with the inspection target, the direction of the magnetic pole of the magnetic generating mechanism is changed. A tilt angle of the magnetism generating mechanism, wherein the tilt angle of the magnetism generating mechanism is variable within a range from a posture orthogonal to the surface to be inspected at 90 degrees to a surface inclined to 20 degrees with respect to the surface to be inspected. The magnetic flaw detector according to claim 13, wherein the permanent magnet is disposed on a side opposite to a side on which the permanent magnet is formed.   21. The magnetic generating mechanism according to claim 12, further comprising: a power supply unit that forms a pair of the magnetic poles for applying magnetism to the object to be inspected and supplies an alternating current to the magnetic generating mechanism. 6. The magnetic flaw detector according to claim 1.   The magnetism generating mechanism forms two pairs of magnetic poles for applying magnetism to the object to be inspected, such that virtual straight lines connecting each pair of magnetic poles are orthogonal, and these are positioned at positions straddling the magnetic inspection sheet. The magnetic flaw detector according to any one of claims 12 to 15, further comprising a power supply unit that has a magnetic pole and supplies an alternating current having a phase difference of 90 degrees to the magnetism generating mechanism.   23. The magnetic flaw detector according to claim 21, wherein an alternating current supplied to a coil provided in the magnetic generator is set higher than a frequency of a commercial power supply.   24. The magnetic inspection apparatus according to claim 12, further comprising an illumination mechanism for illuminating the magnetic inspection sheet.   25. The magnetic flaw detector according to claim 24, wherein the illumination mechanism is configured by a light emitter provided in the magnetic generation mechanism, or is configured by an optical fiber that guides a light beam to a portion of the magnetic generation mechanism.   26. The magnetic inspection sheet according to claim 12, wherein the magnetic sensitive body sealed in the magnetic inspection sheet is formed by coating a magnetic substance with a fluorescent substance, and further includes an ultraviolet ray generating mechanism for illuminating the magnetic inspection sheet with ultraviolet rays. The magnetic flaw detector according to the above.   The magnetic inspection apparatus according to any one of claims 12 to 26, further comprising an imaging mechanism that captures, as an image, a pattern created by the magnetic sensitive body in the magnetic inspection sheet.   28. The magnetic flaw detector according to claim 27, further comprising a recording unit that records an image captured by the imaging mechanism.

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