JP6775410B2 - Magnetic particle flaw detector, magnetic particle flaw detector method - Google Patents

Description

The present invention relates to a flaw detector, a flaw detection method, and a flaw detection inspection liquid, and more specifically, to a magnetic particle flaw detector that performs flaw detection using magnetic powder, a magnetic particle flaw detection method, and a magnetic powder flaw detection inspection liquid.

The magnetic particle flaw detection test is applied to the flaw detection inspection of the surface of an object to be inspected, for example, a billet, an automobile shaft, etc., and is standardized in JIS-Z-2320. In the magnetic particle inspection test, a test solution containing magnetic powder is sprayed on the surface of the object to be inspected, and a magnetic field is applied to the object to be inspected to magnetize the object to be inspected. If there are cracks or other scratches on the surface of the magnetized object to be inspected, magnetic flux leaks from these scratches. The magnetic powder in the inspection liquid flowing on the surface of the object to be inspected is attracted to this leakage flux, and the instruction pattern corresponding to the scratch is formed by the magnetic powder. Then, the scratch is inspected by observing this magnetic particle instruction pattern.

The scratch detection accuracy is improved by reliably forming a magnetic particle instruction pattern corresponding to the scratch. Here, the formation of the magnetic particle instruction pattern is greatly affected by the flow velocity and the flow direction of the test liquid flowing on the surface of the object to be inspected. When the flow velocity of the test liquid is high, the magnetic powder is flown without being attracted by the leakage flux, and it becomes difficult to form the magnetic powder instruction pattern. In particular, when the scratch is small or the depth of the scratch is shallow, the leakage flux that attracts the magnetic powder becomes weak, so that it becomes difficult to form the magnetic powder instruction pattern corresponding to the scratch. On the other hand, when the flow velocity of the test solution is slow, magnetic powder tends to remain in a place different from the scratch, and false detection of the scratch increases. In addition, it takes a lot of time to form the magnetic particle instruction pattern, and the flaw detection time becomes long. Further, when the inspection liquid flows in the direction parallel to the direction in which the scratch extends, the amount of magnetic powder passing over the scratch within a predetermined time is reduced, so that the magnetic powder instruction pattern is less likely to be formed.

Therefore, in order to improve the detection accuracy of scratches, it is important to grasp the flow velocity and flow direction of the test liquid flowing on the surface of the object to be inspected, and to make the flow of the test liquid easy to form the magnetic particle instruction pattern. .. Further, by controlling the flow velocity and the flow direction of the test solution, the scratch detection accuracy can be maintained at a certain level or higher.

Patent Document 1 discloses a configuration in which a magnetic particle flaw detector includes an air blow unit that discharges air toward an object to be inspected in a direction against gravity to adjust the flow velocity of an inspection liquid flowing on the surface of the object to be inspected. Has been done.

Japanese Unexamined Patent Publication No. 2011-38796

According to the magnetic particle flaw detector of Patent Document 1, the flow velocity of the inspection liquid can be stabilized at a desired speed, and a clear magnetic powder instruction pattern can be formed. The magnetic particle flaw detector of Patent Document 1 can stably detect shallow scratches that have been overlooked in the past, and can improve the scratch detection accuracy.

Here, the flow of the test solution is affected by the shape of the object to be inspected, the surface roughness of the object to be inspected, the state of spraying the test solution, and the like, and therefore varies depending on the object to be inspected. Then, the adjustment of the flow velocity and the flow direction of the test solution depends on the skill of the inspector, and there is a concern that the detection accuracy of the scratch may change depending on the inspector. Further, since the test solution flows in the form of a film on the surface of the object to be inspected, it is not easy to actually measure the flow velocity of the test solution. The flow state of the test solution is often monitored visually by an inspector, which makes quantitative evaluation difficult, and there is room for improvement in terms of maintenance and management of detection accuracy.

Therefore, an object of the present invention is to provide a magnetic particle flaw detecting device, a magnetic particle flaw detecting method, and a magnetic particle flaw detecting inspection liquid capable of easily measuring the flow velocity and the flow direction of the inspection liquid flowing on the surface of the object to be inspected.

In order to solve the above problems, the magnetic particle flaw detector of the present invention
A test solution containing magnetic powder and
A spraying part that sprays the test solution on the object to be inspected,
An irradiation unit that irradiates the object to be inspected with light,
An imaging unit that images the surface of the object to be inspected to which the light is irradiated and the inspection liquid flows.
A calculation unit that processes the original image captured by the imaging unit to calculate the flow velocity and flow direction of the test solution flowing on the surface.
With
The test solution further contains a tracer and
The tracer is a non-magnetic material, and when irradiated with the light, it emits light having a brightness or wavelength different from that emitted by the magnetic powder.

Further, the imaging unit is characterized by including a filter through which the light emitted by the tracer is transmitted and the light emitted by the magnetic powder is not transmitted.

Further, the irradiation unit irradiates a pulse of light, and the imaging unit images the surface in synchronization with the pulse irradiation by the irradiation unit.

Further, the irradiation unit is irradiated with ultraviolet rays, and the irradiation unit is irradiated with ultraviolet rays.
The magnetic powder is excited by the ultraviolet rays to emit light.
The tracer is excited by the ultraviolet rays to emit light.

Furthermore, the magnetic particle flaw detection method of the present invention
The process of spraying the inspection liquid containing magnetic powder on the object to be inspected,
The step of irradiating the object to be inspected with light and
A step of photographing the surface of the object to be inspected to which the light is irradiated and the inspection liquid flows,
A step of processing the captured original image to calculate the flow velocity and the flow direction of the test solution flowing on the surface, and
With
The test solution further contains a tracer and
The tracer is a non-magnetic material, and when irradiated with the light, it emits light having a brightness or wavelength different from that emitted by the magnetic powder.

Further, the magnetic particle inspection liquid of the present invention is
Contains magnetic powder and tracer,
The tracer is characterized in that when it is irradiated with light, it emits light having at least a brightness or wavelength different from the light emitted by the magnetic powder.

The magnetic particle flaw detector of the present invention includes an inspection liquid containing magnetic powder, a spraying portion for spraying the inspection liquid on an object to be inspected, an irradiation portion for irradiating the object to be inspected with light, and the light being irradiated to the subject. An imaging unit that images the surface of the object to be inspected through which the test solution flows, a calculation unit that processes the original image captured by the imaging unit and calculates the flow velocity and flow direction of the test solution flowing through the surface. The test solution further contains a tracer, and the tracer is a non-magnetic material and emits light having a brightness or wavelength different from that emitted by the magnetic powder when irradiated with the light. It is possible to provide a magnetic particle flaw detector capable of easily measuring the flow velocity and the flow direction of the inspection liquid flowing on the surface of the object to be inspected.

Further, since the imaging unit includes a filter through which the light emitted by the tracer is transmitted and the light emitted by the magnetic powder is not transmitted, the flow velocity and the flow direction of the inspection liquid flowing on the surface of the object to be inspected can be measured more reliably.

Further, since the irradiation unit irradiates light in a pulse and the imaging unit images the surface in synchronization with the pulse irradiation by the irradiation unit, it is possible to irradiate high-intensity light with an inexpensive configuration, and the productivity is high. Is improved, and energy-efficient measurement becomes possible.

Further, the irradiation unit irradiates ultraviolet rays, the magnetic powder is excited by the ultraviolet rays to emit light, and the tracer is excited by the ultraviolet rays to emit light, so that the inspection liquid flowing on the surface of the object to be inspected. It is possible to provide a magnetic particle flaw detector capable of easily measuring the flow velocity and the flow direction of the ultraviolet rays.

Further, in the magnetic particle inspection method of the present invention, a step of spraying a test solution containing magnetic powder on an object to be inspected, a step of irradiating the object to be inspected with light, and a step of irradiating the light and causing the test solution to flow. The inspection liquid further comprises a step of imaging the surface of the object to be inspected and a step of processing the captured original image to calculate the flow velocity and the flow direction of the inspection liquid flowing through the surface. Since the tracer contained is a non-magnetic material and emits light having a brightness or wavelength different from the light emitted by the magnetic powder when irradiated with the light, the test liquid flowing on the surface of the object to be inspected. It is possible to provide a magnetic particle flaw detection method capable of easily measuring the flow velocity and the flow direction.

Further, the magnetic particle inspection liquid of the present invention contains magnetic powder and a tracer, and when the tracer is irradiated with light, the tracer emits light having a brightness or wavelength different from that emitted by the magnetic powder. It is possible to provide an inspection liquid for magnetic particle inspection that can easily measure the flow velocity and the flow direction of the inspection liquid flowing on the surface of the inspection object.

It is a schematic block diagram which showed an example of the magnetic particle flaw detection apparatus which concerns on this embodiment. It is a schematic block diagram which showed the spraying part, the collecting part, and a tank. It is a block diagram of the control system of a magnetic particle flaw detector. It is the schematic of an example of the image which the locus of a tracer was extracted. It is a flow chart which showed the outline of the magnetic particle inspection method which concerns on this embodiment. It is a flow chart which showed the outline of another magnetic particle inspection method which concerns on this embodiment. It is a time chart which shows the operation of the magnetizing part, the spraying part, the irradiation part, and the imaging part.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, the configuration of the magnetic particle inspection liquid according to the present embodiment will be described in detail. The magnetic particle inspection liquid (hereinafter referred to as an inspection liquid) according to the present embodiment is used for magnetic particle inspection. The test solution is a solution in which magnetic powder and a tracer are mixed with water as a solvent. The magnetic powder is contained in the test solution to detect the scratched portion as a defect. On the other hand, the tracer is included to measure the flow velocity and the flow direction of the test solution flowing on the surface of the test solution.

Magnetic powder is a magnetic substance and is water-insoluble particles as a solvent. The particle size of the magnetic powder is about 3 μm to 70 μm. Tracers are particles that are insoluble in water as a solvent. The particle size of the tracer is about 50 μm to 100 μm. The test solution is used for magnetic particle flaw detection in a state where magnetic powder and tracer are dispersed. Then, the tracer is configured to emit light having at least a brightness or wavelength different from the light emitted by the magnetic powder when irradiated with light.

The light to be irradiated includes ultraviolet rays and visible light. On the other hand, the light emitted by the magnetic powder and the tracer is visible light, and includes light emitted by being excited by ultraviolet rays and reflected light. That is, the magnetic powder and the tracer may be configured to be excited by irradiation with ultraviolet rays to emit light, or may be configured to simply reflect visible light that is not excited by irradiation with ultraviolet rays.

The wavelength of the light emitted by the magnetic powder and the tracer is not particularly limited and may be the same. Further, when the wavelengths of the light emitted by the magnetic powder and the tracer are the same, the magnetic powder and the tracer are configured so that the brightness of the emitted light is different.

As the magnetic powder that is excited by irradiation with ultraviolet rays and emits light, a configuration in which the surface of iron oxide powder is coated with a phosphor can be exemplified. When this magnetic powder is irradiated with ultraviolet rays, a phosphor is excited to emit light. Examples of the tracer that is excited by irradiation with ultraviolet rays to emit light include a structure in which a powder material containing a phosphor is granulated, a structure in which the surface of a powder, for example, a synthetic resin powder is coated with a phosphor, and the like. In this tracer, a phosphor is excited by irradiation with ultraviolet rays to emit light. The magnetic powder and tracer having such a configuration can adjust the brightness and wavelength of the light emitted by the magnetic powder and the tracer by using different phosphors, using different particle diameters, and changing the amount of the phosphors. ..

The magnetic powder that is not excited by irradiation with ultraviolet rays has a structure that does not contain a phosphor and has an iron oxide powder whose surface is not coated with anything, a structure in which the surface of the iron oxide powder is coated with a colorant, and the like. It can be exemplified. This magnetic powder reflects the irradiated visible light. Examples of the tracer that is not excited by irradiation with ultraviolet rays include a synthetic resin powder and a structure in which the surface of the synthetic resin powder is coated with a colorant. This tracer reflects the irradiated visible light. The magnetic powder and the tracer having such a structure are configured so that the wavelengths of the reflected light are different by using colorants having different colors or the like.

The tracer is preferably a non-magnetic material, unlike magnetic powder which is a magnetic material. Although the details will be described later, since the tracer is a non-magnetic material, the tracer does not affect the formation of the magnetic particle instruction pattern for detecting the scratched portion, and the detection accuracy of the scratched portion does not decrease.

The test solution may further contain a dispersant, a rust preventive, or the like. As the dispersant, for example, a polyoxyalkylene allyl phenyl ether type nonionic surfactant and an anionic activator can be used. As the rust preventive, for example, sodium nitrite or the like can be used. Further, the fluorescent material used for the magnetic powder and the tracer may be any one that is excited by ultraviolet rays to emit light, and commercially available fluorescent pigments and fluorescent dyes can be used. In addition, the concentration of the dispersant, rust preventive, etc. in the test solution can be appropriately set. Further, the solvent of the test solution may be white kerosene. When the solvent of the test solution is white kerosene, the magnetic powder and the tracer shall be insoluble in white kerosene.

Next, the configuration of the magnetic particle flaw detector according to the present embodiment will be described in detail. In the following, a magnetic particle flaw detector that performs flaw detection using a test solution containing a magnetic particle and a tracer that are excited by irradiation with ultraviolet rays to emit light will be described as an example. FIG. 1 is a schematic configuration diagram showing an example of a magnetic particle flaw detector 1 according to the present embodiment. FIG. 2 is a schematic configuration diagram showing a spraying unit 13, a collecting unit 14, and a tank 17. Here, for convenience of explanation, in FIG. 1, the side of the imaging unit 16 described later is on the top, and the side of the collecting unit 14 described later is on the bottom. Further, in FIG. 2, the flow direction of the test liquid 11 is indicated by an arrow d1, and the description of the magnetizing unit 12, which will be described later, the irradiation unit 15, the imaging unit 16, and the like, which will be described later, is omitted.

As shown in FIGS. 1 and 2, the magnetic particle flaw detector 1 is configured to detect, for example, a scratched portion as a defect on the surface (outer peripheral surface) of the prismatic object 10 to be inspected by using magnetic powder. .. The magnetic particle inspection device 1 includes an inspection liquid 11, a magnetizing unit 12, a spraying unit 13, a collecting unit 14, an irradiation unit 15, an imaging unit 16, a control unit (not shown), and the like. Although the details will be described later, the magnetic particle flaw detector 1 sprays the inspection liquid 11 containing magnetic powder on the object 10 to be inspected, magnetizes the object 10 to be inspected to which the inspection liquid 11 is sprayed, and magnetizes the magnetic powder on the wound portion. An instruction pattern is formed, the object to be inspected 10 is irradiated with ultraviolet rays, the surface of the object to be inspected 10 irradiated with ultraviolet rays is imaged, and a scratched portion is detected based on the captured image. Further, the magnetic particle flaw detector 1 irradiates the object 10 to be inspected with ultraviolet rays before the object 10 to be magnetized, and images the surface of the object 10 to be inspected to which the ultraviolet rays are irradiated and the inspection liquid 11 flows. It is configured to calculate and measure the flow velocity and the flow direction of the inspection liquid 11 flowing on the surface of the object 10 to be inspected based on the image.

The test liquid 11 is stored in the tank 17. The test liquid 11 contains magnetic powder and a tracer. Magnetic particles and tracers are excited by irradiation with ultraviolet rays to emit light. The magnetic powder and the tracer have substantially the same wavelength of light emitted, and the tracer light is configured to be brighter than the magnetic powder light.

The tank 17 is made of a material that does not affect the physical properties of the stored test solution 11. As the material of the tank 17, for example, stainless steel, aluminum, copper, synthetic resin and the like can be used. The tank 17 includes a stirrer (not shown) that stirs the test liquid 11. As the stirrer, a configuration including a stirrer arranged in the test solution and a rotating device for rotating the stirrer can be exemplified. Then, the inspection liquid 11 is stored in the tank 17 in a state where the magnetic powder and the tracer are dispersed. The configuration of the tank 17 is not particularly limited. The tank 17 may be configured to store the test liquid 11 in a state in which the magnetic powder and the tracer are dispersed. For example, the tank 17 may be further provided with a lid portion that closes the upper opening, or may be configured to include a concentration measuring portion for measuring the concentration of magnetic powder, tracer, etc. contained in the test liquid 11. ..

The magnetizing portion 12 is configured to apply a magnetic field to the object to be inspected 10 to magnetize at least the surface layer portion of the object to be inspected 10. More specifically, the magnetizing portion 12 is configured to magnetize the surface layer portion of the object 10 to be inspected by using an energization method and a coil method. As shown in FIG. 1, the magnetized portions 12 include electrodes 18 and 19 that come into contact with both ends of the object 10 to be inspected and allow an electric current to flow through the object 10 to be inspected, and an exciting coil 20 arranged near both ends of the object 10 to be inspected. , 21 and the like. The object to be inspected 10 is inserted through the exciting coils 20 and 21.

The magnetized portion 12 forms a magnetic field in a direction (circumferential direction) orthogonal to the axial direction of the object to be inspected 10 by passing an electric current through the electrodes 18 and 19 to the object to be inspected 10. Further, the magnetized portion 12 forms a magnetic field in the axial direction of the object to be inspected 10 by flowing an electric current through the exciting coils 20 and 21. Then, by changing the phases of the currents flowing through the electrodes 18 and 19 and the exciting coils 20 and 21, a rotating magnetic field can be applied to the object 10 to be inspected, and the scratched portion extending in any direction on the surface of the object 10 to be inspected. Leakage magnetic flux can also be generated from.

The configuration of the magnetized portion 12 is not particularly limited. The magnetizing portion 12 may be configured to apply a magnetic field to the object to be inspected 10 to magnetize at least the surface layer portion of the object to be inspected 10. The magnetizing portion 12 has a configuration in which the object to be inspected 10 is magnetized by a magnetization method different from the above, such as an interpolar method in which the object to be inspected 10 is arranged between the magnetic poles of an electromagnet or a permanent magnet to magnetize the object to be inspected 10. You may. Then, the magnetization method of the magnetizing portion 12 can be appropriately selected according to the form of the object to be inspected 10.

The spraying unit 13 is configured to spray the test solution 11 on the object to be inspected 10. The spraying unit 13 includes a spraying pump 22 for pumping the test liquid 11, a spraying nozzle 23 for discharging the test liquid 11 pressure-fed by the spraying pump 22, a switching valve 24, and the like.

The suction side of the spray pump 22 is connected to the tank 17 by the pipe 25a. The discharge side of the spray pump 22 is connected to the switching valve 24 by the pipe 25b. The spray nozzle 23 is arranged above the object to be inspected 10 and is connected to the switching valve 24 by the pipe 25c. In addition to the pipes 25b and 25c, the switching valve 24 is connected to the other end of the pipe 25d whose one end is connected to the tank 17.

The switching valve 24 is configured so that the test liquid 11 pumped by the spray pump 22 can flow through the pipe 25c to which the spray nozzle 23 is connected or the pipe 25d connected to the tank 17. The switching valve 24 is a 3-port air-operated valve that operates by air pressure, and is configured so as not to be affected by the magnetic powder contained in the inspection liquid 11. A circulation circuit 26 is formed in which the tank 17, the spray pump 22, and the switching valve 24 to which the spray nozzle 23 is branched and connected are circulated and connected by the pipes 25a, 25b, and 25d.

The test liquid 11 always circulates in the circulation circuit 26. The test liquid 11 circulating in the circulation circuit 26 is maintained in a state in which the magnetic powder and the tracer are dispersed. Then, when the test liquid 11 is sprayed from the spray nozzle 23, the test liquid 11 is sent from the switching valve 24 to the spray nozzle 23. Here, since the test liquid in the pipe 25c when the test liquid 11 circulates in the circulation circuit 26 does not flow, the magnetic powder and the tracer are in a state of settling without being dispersed. However, the pipe 25c only connects the spray nozzle 23 and the switching valve 24, and the amount of the inspection liquid 11 in the pipe 25c is very small. Therefore, the spraying unit 13 can instantly spray the inspection liquid 11 in which the magnetic powder and the tracer are dispersed, and the waiting time until the inspection liquid 11 in which the magnetic powder and the tracer are dispersed is short, and the flaw detection time is reduced. It can be shortened.

The spray nozzle 23 is configured to discharge the test liquid 11 from a large number of discharge ports and spray the test liquid 11. The discharge state of the test liquid 11 to be sprayed can be appropriately selected, and can be changed by changing the number, shape, opening area, flow velocity of the test liquid 11 at the time of discharge, etc. of the spray nozzle 23. it can. For example, the spray nozzle 23 may be configured to include a throttle mechanism capable of adjusting the opening area of the discharge port. The flow velocity at the time of discharging the test liquid 11 can be adjusted by changing the discharge amount of the spray pump 22. The flow rate control valve or the like may be provided on the pipe 25b or the pipe 25c to adjust the flow rate of the test liquid 11 sprayed from the spray nozzle 23.

Here, the tank 17 may be configured so that the test liquid 11 stored by the test liquid 11 discharged from the pipe 25d constituting the circulation circuit 26 is swirled and stirred. With such a configuration, the test liquid 11 can be agitated with a simple configuration without using a stirrer, and the productivity is improved.

The spraying unit 13 sprays the test solution 11 onto the object 10 to be inspected from above. The test liquid 11 to be sprayed is in a state in which magnetic powder and a tracer are dispersed. The sprayed test liquid 11 flows on the surface of the object to be inspected 10 due to the momentum (kinetic energy) and gravity (potential energy) when it is discharged from the spray nozzle 23.

Here, the object 10 to be inspected is magnetized by the magnetizing portion 12 in a state where the inspection liquid 11 is sprayed by the spraying portion 13. When the magnetized object 10 has a scratch as a defect on the surface of the object 10 to be inspected, a leakage magnetic field is generated due to the scratch. The magnetic powder that passes over the wound portion of the magnetized object 10 to be inspected is attracted to the wound portion by the leakage magnetic field. Then, the magnetic powder gathers on the scratched portion due to the leakage magnetic field, so that the magnetic powder instruction pattern caused by the scratched portion is formed.

When the tracer contained in the test liquid 11 is a non-magnetic material, the tracer is not attracted to the scratched portion by the leakage magnetic field. The tracer contained in the inspection liquid 11 has almost no effect on the formation of the magnetic particle instruction pattern, and the detection accuracy of the scratched portion does not decrease.

From the viewpoint of preferably forming the magnetic powder instruction pattern, the flow velocity of the inspection liquid 11 flowing on the surface of the object 10 to be inspected is preferably about 20 mm / s to 100 mm / s, and the spray nozzle is so as to have such a flow velocity. The discharge speed, discharge amount, and the like of the test liquid discharged from 23 are appropriately adjusted. If the flow velocity of the test liquid 11 is larger than 100 mm / s, the magnetic powder is flown without being attracted by the leakage flux, and it becomes difficult to form the magnetic powder instruction pattern. Then, the detection omission of the scratched portion occurs, and the detection accuracy of the scratched portion tends to decrease. On the other hand, when the flow velocity of the test solution is less than 20 mm / s, magnetic powder tends to remain in a portion different from the injured portion, false detection of the injured portion increases, and the detection accuracy of the injured portion tends to decrease. In addition, it takes a lot of time to form the magnetic particle instruction pattern, and the flaw detection time becomes long.

The surplus test liquid 11 sprayed on the object 10 to be inspected by the spraying unit 13 falls downward due to gravity and is collected by the collecting unit 14.

The configuration of the spraying portion 13 is not particularly limited. The spraying unit 13 may be configured to spray the agitated test liquid 11 stored in the tank 17 onto the object 10 to be inspected. For example, the spraying unit 13 may be configured to include a plurality of spraying nozzles 23. Further, the spraying portion 13 may be configured not to include the switching valve 24 and the pipe 25d, that is, to be configured not to include the circulation circuit 26, and the spraying pump 22 and the spraying nozzle 23 may be connected by the pipe 25b. You can also. However, it is preferable to have a configuration including a circulation circuit 26. With such a configuration, the agitated test solution 11 can be sprayed. Further, adhesion of magnetic powder, tracer, etc. to the inner surface of the pipe and clogging of the pipe are prevented, and the inspection liquid 11 can be satisfactorily sprayed. Further, the arrangement of the spray nozzle 23 is not particularly limited. The spraying unit 13 may be configured to spray the test solution 11 onto the test object 10 from the side of the test object 10 or the like.

The recovery unit 14 is configured to collect the test liquid 11 sprayed on the object to be inspected 10 by the spraying unit 13 and return it to the tank 17. The recovery unit 14 has a recovery receiver 27 and a recovery pipe 28. The recovery receiver 27 is a saucer having a substantially U-shaped vertical cross section, and is arranged below the object to be inspected 10. The bottom of the recovery receiver 27 is located above the liquid level of the test liquid 11 in the tank 17. One end of the recovery pipe 28 is connected to the bottom of the recovery receiver 27, and the other end is connected to the tank 17.

The collection unit 14 collects the test liquid 11 sprayed on the object 10 to be inspected by the spraying unit 13 by the collection receiver 27, and returns the collected test liquid 11 to the tank 17. Therefore, the test liquid 11 recovered by the recovery unit 14 is reused as the test liquid 11 sprayed by the spraying unit 13, and the burden on the environment and the disposal cost of the test liquid 11 can be reduced.

The configuration of the collection unit 14 is not particularly limited. The recovery unit 14 may be configured to collect the test liquid 11 sprayed by the spraying unit 13 and return it to the tank 17. For example, the recovery unit 14 may be configured to include a pump that pumps the test liquid 11 recovered by the recovery receiver 27 to the tank 17. With such a configuration, the recovery receiver 27 can be arranged below the liquid level of the test liquid in the tank 17, and the degree of freedom in design is increased. In addition, the test liquid 11 recovered by the recovery receiver 27 can be reliably returned to the tank 17, and overflow of the test liquid 11 in the recovery receiver 27 can be prevented. Further, the collection receiver 27 may be configured to cover the side of the object to be inspected 10. With such a configuration, the test liquid 11 sprayed by the spraying unit 13 can be recovered more reliably.

The irradiation unit 15 is configured to irradiate the surface (outer peripheral surface) of the object to be inspected 10 imaged by the imaging unit 16 described later with ultraviolet rays as light. The irradiation unit 15 includes an ultraviolet LED (Light Emitting Diode) or an ultraviolet lamp as a light source, a fan (not shown) as a cooling device, and the like. The irradiation unit 15 is arranged above the object to be inspected 10. Then, the irradiation unit 15 irradiates the surface of the object to be inspected 10 imaged by the imaging unit 16 with ultraviolet rays from above. The magnetic powder and the tracer contained in the test liquid 11 are excited by the ultraviolet rays in the region irradiated with the ultraviolet rays by the irradiation unit 15 and emit light.

The configuration of the irradiation unit 15 is not particularly limited. The irradiation unit 15 may be configured to irradiate the surface of the object to be inspected 10 with light so that the imaging unit 16 can image at least the magnetic powder and the tracer in the imaging region. Then, the irradiation unit 15 is configured to irradiate light according to the configuration of the test liquid 11. For example, when the magnetic powder and the tracer contained in the test liquid 11 are not excited by ultraviolet rays, the irradiation unit 15 is configured to irradiate the surface of the object 10 to be inspected with visible light, for example, white light.

The irradiation unit 15 may be configured to include a magnetic shield in order to avoid the influence of the magnetic field generated by the magnetization unit 12. Further, the arrangement of the irradiation unit 15 is not particularly limited. The irradiation unit 15 may be configured to irradiate the surface of the object 10 to be inspected with ultraviolet rays from the side or the like.

The irradiation unit 15 may be configured to pulse-irradiate ultraviolet rays or visible light. With such a configuration, the irradiation unit 15 does not need to be configured to be able to constantly irradiate high-intensity ultraviolet rays or visible light, and can be made inexpensive. In addition, the irradiation unit 15 can irradiate energy-efficient light without irradiating unnecessary light. Further, the change in viscosity due to the temperature rise of the test liquid 11 is prevented, the flow velocity of the test liquid 11 is unlikely to change, and the decrease in the detection accuracy of the scratched portion can be prevented. In addition, the life of the light source of ultraviolet rays and visible light can be expected to be extended. The pulse irradiation time is appropriately set according to the flow velocity of the test liquid 11 flowing on the surface of the object to be inspected 10.

The image pickup unit 16 is configured to image the surface of the object to be inspected 10 irradiated with ultraviolet rays as light by the irradiation unit 15. The imaging unit 16 is arranged above the object to be inspected 10 and images the surface of the object to be inspected 10 from above. The original image captured by the imaging unit 16 is sent to a control unit (not shown here). The magnetic powder and the tracer in the imaging region of the imaging unit 16 are excited by the ultraviolet rays of the irradiation unit 15 to emit light.

An area camera can be used as the image pickup unit 16, and the image pickup unit 16 is not particularly limited. For example, a CCD (Charge Coupled Device) camera can be used. The shutter speed of the imaging unit 16 and the resolution of the image to be imaged are appropriately set according to the intensity of the light emitted by the irradiation unit 15, the flow velocity of the inspection liquid 11 flowing on the surface of the object 10 to be inspected, and the like. The image captured by the image pickup unit 16 may be a color image or a monochrome image.

Here, the imaging unit 16 is configured to image the surface of the object 10 to be inspected in the two states. On the other hand, the object to be inspected 10 is not magnetized, and the test solution 11 is flowing on the surface of the object to be inspected 10, and the test solution 11 is being sprayed. The other is a state in which the magnetic powder instruction pattern is formed after the spraying of the test solution 11 is completed. Although the details will be described later, the image captured in one of the states is used to measure the flow velocity and the flow direction of the test liquid 11 flowing on the surface of the object to be inspected 10. The image captured in the other state is used to detect a scratch on the surface of the object 10 to be inspected. In the other state, the object to be inspected 10 is preferably magnetized. With such a configuration, it is possible to prevent the magnetic particle instruction pattern from being distorted due to the magnetic powder being blown off.

The configuration of the imaging unit 16 is not particularly limited. For example, the imaging unit 16 may be configured to include a magnetic shield in order to avoid the influence of the magnetic field generated by the magnetizing unit 12. Further, when the irradiation unit 15 irradiates a pulse of ultraviolet rays or visible light, the image pickup unit 16 is configured to take an image in synchronization with the pulse irradiation of the irradiation unit 15. Further, the imaging unit 16 may be configured to capture a plurality of images, or may be configured to capture a moving image. Further, the arrangement of the imaging unit 16 is not particularly limited. The imaging unit 16 may be configured to image the surface of the object 10 to be inspected from the side or the like.

Next, the control system of the magnetic particle flaw detector 1 according to the present embodiment will be described. FIG. 3 is a block diagram of the control system of the magnetic particle flaw detector 1. The magnetic particle flaw detection device 1 includes a control unit 30, in which the magnetization unit 12, the spraying unit 13, the irradiation unit 15, the imaging unit 16, and the like are controlled by the control unit 30, and as defects on the surface of the object 10 to be inspected by automatic control. It is configured to be able to detect scratches on the surface.

The control unit 30 is configured to control the operation of the magnetic particle inspection device 1 by reading input signals such as various set values and detection values by various sensors and outputting the control signals. Examples of the control unit 30 include a microcomputer (Central Processing Unit) that performs arithmetic processing and control processing, a main storage device that stores data, a timer, an input circuit, an output circuit, a power supply circuit, and the like. To. The main storage device exemplified by the ROM (Read Only Memory) and the EEPROM (Electrically Erasable Programmable Read Only Memory) stores a control program for executing the operation according to the present embodiment and various data. It should be noted that these various programs, data, and the like may be stored in an external storage device and read by the control unit 30.

A magnetizing unit 12, a spraying unit 13, an irradiation unit 15, an imaging unit 16, and the like are electrically connected to the control unit 30. Various sensors and the like other than those shown in FIG. 3 are electrically connected to the control unit 30.

The control unit 30 has a detection unit 31. The detection unit 31 is composed of, for example, a program. The detection unit 31 is configured to detect defects on the surface of the object 10 to be inspected by performing a predetermined process (image process) on the image signal (original image) input from the image pickup unit 16. The object to be image-processed by the detection unit 31 is that the object to be inspected 10 is magnetized, and the surface of the object to be inspected 10 on which the magnetic particle instruction pattern is formed is after the spraying of the inspection liquid 11 is completed. This is the captured original image.

The detection unit 31 performs an enhancement process on the original image so that the magnetic particle instruction pattern in the original image is emphasized. As the enhancement process, for example, a LUT (Look Up Table) conversion process, an enlargement / contraction process, a shading process, and a process combining these various processes can be used.

Next, the detection unit 31 binarizes the emphasized image with a predetermined threshold value stored in the main storage device to extract the magnetic particle instruction pattern. This threshold value is appropriately set according to the brightness of the light emitted by the magnetic powder and the tracer, and is set so that the light emitted by the tracer is not included in the image from which the magnetic powder instruction pattern is extracted. Therefore, even if the light emitted by the tracer is shown in the original image, the tracer does not affect the extraction of the magnetic particle instruction pattern. Then, the detection unit 31 performs a process based on elements related to the shape such as an area, a length, a width, etc. on the extracted magnetic powder instruction pattern to extract a scratched portion as a defect.

The detection unit 31 is not limited to the above configuration. The detection unit 31 may be configured so that defects can be detected from the original image. The detection unit 31 may have a configuration in which, for example, the extracted magnetic powder instruction pattern is subjected to an expansion treatment and then the scratched portion is extracted. The expansion treatment is a treatment for expanding the extracted magnetic powder instruction pattern in a predetermined direction by a predetermined amount. It is possible to compensate for the breakage of the magnetic particle instruction pattern extracted by the expansion treatment, and the detection accuracy of the scratched portion is improved. Further, the detection unit 31 may be configured to perform binarization processing on the original image a plurality of times with different threshold values.

Further, the detection unit 31 may be configured to process a plurality of image processes in parallel by pipeline processing. With such a configuration, the time required to determine the presence or absence of a scratched portion can be shortened.

The detection unit 31 detects the scratched portion by real-time processing linked with the imaging by the imaging unit 16. However, the detection unit 31 may detect the scratched portion by batch processing in which a plurality of original images captured by the imaging unit 16 are accumulated and then processed without interlocking with the imaging by the imaging unit 16. With such a configuration, the calculation load of the control unit 30 by the detection unit 31 is reduced, and the productivity is improved.

Further, the detection unit 31 may be provided in another control unit connected to the control unit 30. With such a configuration, the calculation load of the control unit 30 is reduced, and for example, the magnetic particle flaw detector 1 can smoothly perform various processes in real time, and the detection time can be shortened.

The control unit 30 further has a calculation unit 32. The calculation unit 32 is composed of, for example, a program. The calculation unit 32 is configured to calculate the flow velocity and the flow direction of the test liquid 11 flowing on the surface of the object to be inspected 10 by performing predetermined image processing on the original image input from the image pickup unit 16. The object to be image-processed by the calculation unit 32 is that the object 10 to be inspected is not magnetized, the inspection liquid 11 is flowing on the surface, and the surface of the object 10 to be inspected while the inspection liquid 11 is being sprayed is This is the captured original image.

Here, the tracer flows together with water, which is the solvent of the test solution 11. That is, the speed and the moving direction of the tracer are substantially the same as the flow velocity and the flow direction of the test liquid 11. Then, the trail of light emitted by the tracer (trajectory of the tracer) is captured in the original image. The calculation unit 32 calculates the flow velocity and the flow direction of the test liquid 11 from the trajectory of the tracer.

The calculation unit 32 first performs an enhancement process on the original image so that the tracer trajectory in the original image is emphasized. As the enhancement process, for example, a LUT (Look Up Table) conversion process, an enlargement / contraction process, a shading process, and a process combining these various processes can be used.

Next, the calculation unit 32 binarizes the emphasized image with a predetermined threshold value stored in the main storage device to extract the tracer trajectory. FIG. 4 shows a schematic view of an example of an image in which the tracer locus 33 is extracted. This threshold value is appropriately set according to the brightness of the light emitted by the magnetic powder and the tracer, and is set so that the light emitted by the magnetic powder is not included in the image extracted from the trace 33 of the tracer. Therefore, even if the light emitted by the magnetic powder is reflected in the original image, the magnetic powder does not affect the extraction of the trace 33 of the tracer.

Then, the calculation unit 32 calculates the speed and the moving direction of the tracer as the flow velocity and the flow direction of the test liquid 11 based on the extracted tracer locus 33 and the shutter speed of the imaging unit 16. The calculated speed and moving direction of the tracer are stored in the main storage device of the control unit 30 as the flow velocity and flow direction of the test liquid 11, and are displayed on a display unit (not shown).

When extracting the tracer locus 33, the calculation unit 32 excludes the tracer locus 33 that intersects the edge of the image, the tracer locus 33 that intersects the other tracer locus 33, and the like. It also performs processing. The calculation unit 32 can calculate the speed and the moving direction of the tracer with higher accuracy by this exclusion process.

Here, the test liquid 11 flows in the form of a film on the surface of the object to be inspected 10. The film thickness of the test solution 11 is, for example, 2 mm or less. It is difficult to actually measure the flow velocity and flow direction of such a flow. However, the calculation unit 32 can calculate the speed and the moving direction of the test liquid 11 based on the original image captured by the imaging unit 16. Therefore, the magnetic particle flaw detector 1 can easily measure the speed and the moving direction of the inspection liquid 11.

Further, since the speed and the flow direction of the test liquid 11 are calculated and measured by image processing, the measurement is performed without any variation depending on the inspector performing the measurement. The inspector can quantitatively evaluate the flow state of the test solution 11 from this measured value. Therefore, the magnetic particle flaw detector 1 can satisfactorily maintain and manage the detection accuracy of the scratched portion.

When the trajectories of a plurality of tracers are extracted, the calculation unit 32 may calculate the speed and the moving direction of each tracer to create the flow distribution of the test liquid 11. Further, the calculation unit 32 may calculate the speed and the moving direction of each tracer, and use the average as the flow velocity and the flow direction of the test liquid 11.

Here, from the viewpoint of satisfactorily measuring the flow velocity and the flow direction of the test solution 11, the concentration of the tracer is preferably 50 pieces / mL to 500 pieces / mL. When the concentration of the tracer is less than 50 pieces / mL, the number of tracer trajectories 33 appearing in the captured original image is reduced, and it becomes difficult to calculate the flow velocity and the flow direction of the test solution 11. When the concentration of the tracer is larger than 500 / mL, the number of tracer trajectories 33 appearing in the captured original image increases, the tracer trajectories 33 intersect, and the flow velocity and flow direction of the test liquid 11 Is difficult to calculate. In addition, the calculation load of the control unit 30 by the calculation unit 32 increases.

Further, the number of tracer trajectories 33 appearing in the original image for which the calculation unit 32 performs image processing is preferably 5 to 50. If the number of tracer trajectories 33 is less than 5, it becomes difficult to calculate the flow velocity and flow direction of the test liquid 11. If the number of tracer trajectories 33 is larger than 50, it becomes difficult to calculate the flow velocity and flow direction of the test liquid 11 due to the intersection of tracer trajectories 33 and the like. In addition, the calculation load of the control unit 30 by the calculation unit 32 increases.

Further, the ratio of the fluorescence coefficient of the tracer to the fluorescence coefficient of the magnetic powder is preferably 5 or more. If this ratio is less than 5, it becomes difficult to distinguish between the light emitted by the magnetic powder and the light emitted by the tracer in the image processing in the detection unit 31 and the calculation unit 32, and the detection of the scratched portion and the flow velocity and flow of the inspection liquid 11 It becomes difficult to calculate the direction. Here, the fluorescence coefficient has a unit of cd / W and is one index representing the brightness defined by JIS-Z-2320, and is the surface brightness (W / m ² ) with respect to the surface ultraviolet irradiance (W / m ² ). cd / m ² ). When the magnetic powder and the tracer contained in the test liquid 11 are not excited by ultraviolet rays, the tracer reflects the brightness (cd / m ² ) of the light reflected by the magnetic powder when irradiated with visible light of the same intensity. The ratio of the brightness (cd / m ² ) of the light to be emitted is preferably 5 or more.

Further, the shutter speed of the imaging unit 16 when the original image processed by the calculation unit 32 is imaged includes the flow velocity of the test solution 11, the brightness of the light emitted by the tracer, the size of the imaging range of the imaging unit 16, and the like. It is appropriately set according to the above, and is set to, for example, 1 ms to 100 ms. The length of the tracer trajectory 33 to be imaged changes according to the shutter speed.

Further, the shutter speed of the imaging unit 16 when capturing the original image processed by the detection unit 31 is appropriately set according to the brightness of the light emitted by the magnetic powder and the like. The shutter speed of the imaging unit 16 may be the same as or different from the shutter speed of the imaging unit 16 when the original image processed by the calculation unit 32 is imaged.

Further, when the irradiation unit 15 irradiates the ultraviolet rays in a pulsed manner, the shutter speed of the imaging unit 16 when the original image processed by the calculation unit 32 is imaged is longer than the time during which the irradiation unit 15 is irradiating the ultraviolet rays. You may. In this case, the irradiation unit 15 is configured to pulse ultraviolet rays while the imaging unit 16 is opening the shutter. The length of the tracer locus 33 to be imaged changes according to the time during which the irradiation unit 15 is irradiating the ultraviolet rays. Then, the calculation unit 32 calculates the flow velocity and the flow direction of the test liquid 11 based on this time and the trace 33 of the extracted tracer.

With such a configuration, the irradiation time of the ultraviolet rays of the irradiation unit 15 can be minimized, and the irradiation unit 15 can be made inexpensive. Further, the irradiation unit 15 does not irradiate the ultraviolet rays that are unnecessary for the imaging of the imaging unit 16, and can irradiate the ultraviolet rays with high energy efficiency.

The calculation unit 32 is not limited to the above configuration. The calculation unit 32 may be configured to calculate the flow velocity and the flow direction of the test liquid 11 from the original image. For example, the calculation unit 32 performs image processing on two original images captured with a minute time difference, tracks the light emitted by the tracer, calculates the speed and the moving direction of the tracer, and calculates the flow velocity and the flow of the test liquid 11. It may be configured in a direction. Further, the calculation unit 32 may be configured to perform the binarization process a plurality of times with different threshold values on the original image.

Further, the calculation unit 32 may be configured to perform image processing on a plurality of original images, extract the tracer locus 33, and calculate the flow velocity and the flow direction of the test liquid 11. With such a configuration, the number of tracer trajectories 33 to be extracted increases, and the flow velocity and flow direction of the test liquid 11 can be measured with higher accuracy. In addition, it becomes easy to create a flow distribution of the test solution 11.

Further, the calculation unit 32 may be configured such that when a plurality of tracer trajectories 33 are extracted, the tracer trajectories 33 used for calculating the flow velocity and the flow direction of the test liquid 11 are selected by the inspector. good.

Further, the original image to be image-processed by the calculation unit 32 may be an original image in which the inspection liquid 11 is flowing on the surface and the surface of the object to be inspected 10 while the inspection liquid 11 is being sprayed is captured. .. When the tracer of the test liquid 11 is a non-magnetic material, the object 10 to be inspected may be in a magnetized state. The non-magnetic tracer is not affected even if the object 10 to be inspected is magnetized. Then, the calculation unit 32 can calculate the velocity and the moving direction regardless of the presence or absence of magnetization of the object 10 to be inspected.

From the viewpoint of satisfactorily calculating the flow velocity and the flow direction of the test liquid 11, the original image processed by the calculation unit 32 is preferably an image in which the object to be inspected 10 is not magnetized. That is, it is preferable that the image is in a state where the magnetic particle instruction pattern is not formed. With such a configuration, the calculation unit 32 does not need to distinguish between the light emitted by the tracer and the magnetic particle instruction pattern in the original image to be image-processed, and can easily measure the flow velocity and the flow direction of the inspection liquid 11. Become. In addition, the flow velocity and flow direction of the test liquid 11 can be measured with higher accuracy.

Further, the calculation unit 32 may be configured to process a plurality of image processes in parallel by pipeline processing. With such a configuration, the time required to measure the flow velocity and the flow direction of the test liquid 11 can be shortened.

The calculation unit 32 calculates the flow velocity and the flow direction of the test liquid 11 by real-time processing linked with the imaging by the imaging unit 16. However, the calculation unit 32 calculates the flow velocity and the flow direction of the test liquid 11 by batch processing in which a plurality of original images captured by the imaging unit 16 are accumulated and then processed without being linked with the imaging by the imaging unit 16. You may. With such a configuration, the calculation load of the control unit 30 by the calculation unit 32 is reduced, and the productivity is improved. Further, it is possible to grasp the flow state of the test liquid 11 based on a large number of calculated flow velocities and flow directions of the test liquid 11. Based on this flow state, it becomes easy to improve and optimize the spraying of the test solution 11, and it is possible to improve the detection accuracy of the scratched portion.

Further, the calculation unit 32 may be provided in another control unit connected to the control unit 30. With such a configuration, the calculation load of the control unit 30 is reduced, and for example, the magnetic particle flaw detector 1 can smoothly perform various processes in real time.

The magnetic particle flaw detector 1 is not limited to the above configuration. The magnetic particle flaw detector 1 is appropriately changed according to the configuration of the inspection liquid 11. For example, when the magnetic powder and the tracer contained in the test liquid 11 are configured to emit light having different wavelengths, the imaging unit 16 may be configured to capture a color image. Further, the detection unit 31 is configured to perform image processing on the original image using a threshold value set according to the wavelength of the magnetic powder and the light emitted by the tracer to extract the magnetic powder instruction pattern. This threshold value is set so that the image from which the magnetic particle instruction pattern is extracted does not include the light emitted by the tracer. Further, the calculation unit 32 is configured to perform image processing on the original image using a threshold value set according to the wavelength of the magnetic powder and the light emitted by the tracer to extract the tracer locus 33, similarly to the detection unit 31. Will be done. This threshold value is set so that the light emitted by the magnetic powder is not included in the image obtained by extracting the trace 33 of the tracer.

With such a configuration, the magnetic particle inspection device 1 is configured so that the magnetic powder and the tracer contained in the inspection liquid 11 emit light having different wavelengths, and the inspection liquid 11 flows on the surface of the inspection liquid 10. The speed and the direction of movement can be easily measured.

Further, when the magnetic particle and the tracer are configured to emit light having different wavelengths in this way, the magnetic particle flaw detector 1 may be configured to include two imaging units 16. On the other hand, the imaging unit 16 is configured to include a filter through which the light emitted by the magnetic powder is transmitted and the light emitted by the tracer is not transmitted. The other imaging unit 16 is configured to include a filter through which the light emitted by the tracer is transmitted and the light emitted by the magnetic powder is not transmitted. The detection unit 31 performs image processing on the original image captured by one of the imaging units 16 to detect the scratched portion. The calculation unit 32 performs image processing on the original image captured by the other imaging unit 16 to calculate the flow velocity and the flow direction of the test liquid 11.

Even with such a configuration, when the magnetic particle flaw detector 1 is configured so that the magnetic powder and the tracer contained in the inspection liquid 11 emit light having different wavelengths, the inspection liquid 11 flows on the surface of the object to be inspected 10. The speed and the direction of movement can be easily measured.

Here, the light emitted by the tracer is not reflected in the original image captured by one of the imaging units 16, that is, the original image for which the detection unit 31 performs image processing. Further, the magnetic powder instruction pattern is not reflected in the original image captured by the other imaging unit 16, that is, the original image processed by the calculation unit 32. Therefore, the detection unit 31 does not need to distinguish between the light emitted by the tracer and the magnetic particle instruction pattern in the image processing, and can detect the scratched portion with higher accuracy by a relatively simple image processing. Similarly, the calculation unit 32 does not need to distinguish between the light emitted by the tracer by the image processing and the magnetic particle instruction pattern, and can calculate the flow velocity and the flow direction of the inspection liquid 11 with higher accuracy by relatively simple image processing. .. Therefore, the calculation load of the control unit 30 by the detection unit 31 and the calculation unit 32 is reduced, and the productivity is improved. Further, the magnetic particle inspection device 1 improves the detection accuracy of the scratched portion and the measurement accuracy of the flow velocity and the flow direction of the inspection liquid 11.

It should be noted that one of the imaging units 16 does not have to be provided with a filter through which the light emitted by the magnetic powder is transmitted and the light emitted by the tracer is not transmitted. The detection unit 31 is performed based on the original image captured in a state where the test liquid 11 does not flow on the surface of the object 10 to be inspected. The tracer shown in the original image captured in this state remains on the surface of the object 10 to be inspected. Therefore, even if one of the imaging units 16 is not provided with a filter, the number of tracers captured in the original image captured by the one imaging unit 16 is small, and the same effect as described above can be obtained.

The magnetic particle flaw detector 1 may be configured to include one imaging unit 16 that can switch between the above two filters. Further, the magnetic particle inspection device 1 may be configured to include one imaging unit 16 which is detachably provided with a filter which allows light emitted by the tracer to be transmitted and does not transmit light emitted by magnetic powder. With such a configuration, the same effect as that of the configuration including the above-mentioned two imaging units 16 can be obtained, the number of parts is reduced, and the productivity is improved.

When the magnetic powder and the tracer are configured to emit light having different wavelengths, the tracer is preferably a non-magnetic material. With such a configuration, it is possible to prevent the magnetic powder instruction pattern from being formed only by the magnetic powder and the extraction of the magnetic powder instruction pattern by the detection unit 31 from becoming complicated.

Further, when the magnetic powder and the tracer are not excited by irradiation with ultraviolet rays, the irradiation unit 15 is configured to irradiate visible light, for example, white light. Here, the magnetic powder and the tracer are configured so that the wavelengths of the reflected light are different. Therefore, similarly to the case where the magnetic powder and the tracer described above are configured to emit light having different wavelengths, the magnetic particle flaw detector 1 has a configuration in which the imaging unit 16 can capture a color image, or two imaging units 16 are provided. It is configured to be prepared. With such a configuration, the magnetic particle flaw detector 1 can determine the speed and moving direction of the inspection liquid 11 flowing on the surface of the object 10 to be inspected even if the magnetic particle and the tracer are not excited by irradiation with ultraviolet rays. It can be easily measured.

When the wavelength of the light emitted or reflected by the magnetic powder is different from the wavelength of the light emitted or reflected by the tracer, the absolute value of the difference between these wavelengths is preferably 100 nm or more. With such a configuration, in the image processing in the detection unit 31 and the calculation unit 32, it becomes easy to distinguish between the light emitted by the magnetic powder and the light emitted by the tracer, and the detection of the scratched portion and the flow velocity of the inspection liquid 11 and the flow velocity of the inspection liquid 11 and The flow direction can be calculated easily.

Further, the magnetic particle inspection device 1 includes a determination unit for determining whether the flow velocity and the flow direction of the measured inspection liquid 11 are within a predetermined range, and an alarm unit for notifying the inspector of an abnormality by sound or light. It may be provided. As the determination unit, a program provided in the control unit 30 can be exemplified. Examples of the alarm unit include an alarm sound generator and a lamp blinking device, which are controlled by the control unit 30. Then, the magnetic particle inspection device 1 determines whether the flow velocity and the flow direction of the inspection liquid 11 measured by the determination unit are within a predetermined range, and operates the alarm unit when it is determined that the inspection liquid 11 is out of the range. It may be configured to notify the inspector of the abnormality.

With such a configuration, for example, when detecting a plurality of objects 10 having the same shape, the inspector does not have to pay much attention to the change in the flow state of the inspection liquid 11, which imposes a burden on the inspector. It is reduced and the maintenance of the detection accuracy of the scratched portion can be easily performed.

Further, the magnetic particle flaw detection device 1 is not limited to a configuration in which the original image captured by the imaging unit 16 is subjected to image processing to detect the scratched portion. For example, the magnetic particle flaw detector 1 may be configured so that the inspector visually observes the magnetic particle instruction pattern formed on the object 10 to be inspected and the inspector detects the scratched portion.

Further, the magnetic particle inspection device 1 may have a configuration in which the magnetizing unit 12, the spraying unit 13, the irradiation unit 15, the imaging unit 16, and the like are manually operated by an inspector. With such a configuration, the configuration of the control unit 30 is simplified and the productivity is improved.

As described above, the magnetic particle flaw detector 1 according to the present embodiment has the inspection liquid 11 containing the magnetic powder, the spraying portion 13 for spraying the inspection liquid 11 on the inspection object 10, and the inspection object 10. The irradiation unit 15 that irradiates light, the image pickup unit 16 that images the surface of the object 10 to be inspected that is irradiated with light and the inspection liquid 11 flows, and the original image captured by the image pickup unit 16 are processed and flow through the surface. A calculation unit 32 for calculating the flow velocity and flow direction of the test liquid 11 is provided, the test liquid 11 further contains a tracer, and the tracer is at least as bright as the light emitted by the magnetic powder when irradiated with light. It emits light of different wavelengths.

According to the present embodiment, it is possible to provide a magnetic particle flaw detector capable of easily measuring the flow velocity and the flow direction of the inspection liquid 11 flowing on the surface of the object to be inspected 10.

Further, the magnetic particle inspection liquid 11 according to the present embodiment contains magnetic powder and a tracer, and the tracer emits light having at least a brightness or wavelength different from the light emitted by the magnetic powder when irradiated with light.

According to the present embodiment, it is possible to provide an inspection liquid for magnetic particle inspection that can easily measure the flow velocity and the flow direction of the inspection liquid 11 flowing on the surface of the object to be inspected 10.

Here, the test solution 11 according to the present embodiment has a configuration in which a tracer is further contained in the solution containing magnetic powder used for magnetic particle inspection. Therefore, the test solution 11 can be easily and inexpensively produced.

Further, in the magnetic particle flaw detector that detects a scratched portion by image processing, the inspection liquid further contains a tracer, and the calculation unit 32 composed of a program is further provided, whereby the magnetic particle flaw detector according to the present embodiment is provided. It becomes the device 1. Therefore, the magnetic particle flaw detector 1 according to the present embodiment can be easily and inexpensively manufactured without changing the main configuration of the magnetic particle flaw detector that detects a scratched portion by image processing.

Next, the outline of the magnetic particle flaw detection method according to the present embodiment will be described. In the following, the scratched portion on the surface of the object 10 to be inspected by the magnetic particle flaw detector 1 shown in FIGS. 1 to 3 is used with the inspection liquid 11 containing the magnetic powder and the tracer which are excited by irradiation with ultraviolet rays to emit light. The flaw detection will be illustrated and described. FIG. 5 is a flow chart showing an outline of the magnetic particle flaw detection method according to the present embodiment. In this embodiment, a step of spraying the test liquid 11 on the test object 10, a step of irradiating the test object 10 with light, and an image of the surface of the test object 10 to which the light is irradiated and the test liquid 11 flows are imaged. It is characterized by including a step and a step of processing the captured original image to calculate the flow velocity and the flow direction of the test liquid 11 flowing on the surface. In the following, each step will be described in more detail.

First, the spraying unit 13 starts spraying the test solution 11 on the surface of the object 10 to be inspected (step S1). As described above, the spraying unit 13 sprays the inspection liquid 11 in a state where the magnetic powder and the tracer are dispersed from above on the object 10 to be inspected. The surplus test solution sprayed on the object to be inspected 10 by the spraying unit 13 falls downward due to gravity and is collected by the collecting unit 14.

Next, the surface of the object to be inspected 10 is first irradiated with ultraviolet rays by the irradiation unit 15 (step S2). As described above, the irradiation unit 15 irradiates the surface of the object to be inspected 10 imaged by the imaging unit 16 with ultraviolet rays as light from above. The magnetic powder and the tracer contained in the test liquid 11 are excited by the ultraviolet rays in the region irradiated with the ultraviolet rays by the irradiation unit 15 and emit light.

Next, the first imaging by the imaging unit 16 is performed (step S3). At this time, the test liquid 11 is flowing on the surface of the object to be inspected 10. The image pickup unit 16 is a region where ultraviolet rays are irradiated by the irradiation unit 15 as the first image pickup, and the inspection liquid 11 is flowing on the surface of the image pickup unit 16 and the object to be inspected while the inspection liquid 11 is being sprayed. The surface of 10 is imaged. That is, the first imaging is an imaging of the surface of the object 10 to be inspected, which is irradiated with ultraviolet rays and through which the inspection liquid 11 flows. The captured original image is sent to the control unit 30. The first irradiation of ultraviolet rays (step S2) is continued until the first imaging (step S3) is completed.

Next, the calculation unit 32 calculates the flow velocity and the flow direction of the test liquid 11 flowing on the surface of the object to be inspected 10 (step S4). The calculation unit 32 performs predetermined image processing on the original image captured in the first imaging (step S3) to extract the tracer locus 33. Then, the calculation unit 32 calculates the speed and the moving direction of the tracer based on the extracted tracer locus 33 and the shutter speed in the first imaging (step S3) as the flow velocity and the flow direction of the test liquid 11. The calculated speed and moving direction of the tracer are stored in the main storage device of the control unit 30 as the flow velocity and flow direction of the test liquid 11, and are displayed on a display unit (not shown).

Here, the calculation of the flow velocity and the flow direction of the test liquid 11 is performed based on the original image captured in the first imaging (step S3). Therefore, even if the test liquid 11 flows on the surface of the object 10 in the form of a film, its flow velocity and flow direction can be easily calculated. Further, the calculated speed and flow direction of the inspection liquid 11 do not vary depending on the inspector performing the magnetic particle inspection.

Next, the object to be inspected 10 is magnetized by the magnetizing portion 12 (step S5). As described above, the magnetizing portion 12 applies a rotating magnetic field to the object to be inspected 10 to magnetize the surface layer portion of the object to be inspected 10. When there is a scratch on the surface of the object 10 to be inspected, leakage flux is generated from the scratch regardless of the extending direction of the scratch. The magnetization of the object to be inspected 10 (step S5) is continued until the second imaging by the imaging unit 16 described later is completed.

Next, the spraying unit 13 stops spraying the test solution 11 on the surface of the object 10 to be inspected (step S6). Stopping the spraying of the test liquid 11 (step S6) is performed after a predetermined time has elapsed from the start of the magnetization of the object 10 to be inspected (step S5). From step S5 to step S6, the test solution 11 continues to flow on the surface of the magnetized object 10 to be inspected. When there is a scratched portion on the surface of the object to be inspected 10, the magnetic powder contained in the inspection liquid 11 is attracted to the leaked magnetic field caused by the scratched portion, and the magnetic powder instruction pattern caused by the scratched portion is formed. When the tracer contained in the test liquid 11 is a non-magnetic material, the tracer is not attracted to the scratched portion by the leakage magnetic field, and the tracer does not affect the formation of the magnetic particle instruction pattern.

Next, the irradiation unit 15 irradiates the surface of the second object to be inspected 10 with ultraviolet rays (step S7). Similar to the first irradiation of ultraviolet rays (step S2), the irradiation unit 15 irradiates the surface of the object 10 to be imaged by the imaging unit 16 with ultraviolet rays as light from above. The region irradiated with ultraviolet rays by the second irradiation of ultraviolet rays (step S7) is the same as the region irradiated with ultraviolet rays by the first irradiation of ultraviolet rays (step S2). When there is a magnetic powder instruction pattern in the region irradiated with ultraviolet rays by the irradiation unit 15, the phosphor of the magnetic powder forming the magnetic powder instruction pattern is excited and emits light.

Next, a second image pickup is performed by the image pickup unit 16 (step S8). At this time, the test liquid 11 does not flow on the surface of the object to be inspected 10. The image pickup unit 16 is a region irradiated with ultraviolet rays by the irradiation unit 15 as the second image pickup, and is inspected in which the magnetic powder instruction pattern is formed after the inspection liquid 11 has been sprayed. The surface of the object 10 is imaged. The region imaged by the second imaging (step S8) is the same as the region imaged by the first imaging (step S3). The captured original image is sent to the control unit 30. The second irradiation of ultraviolet rays (step SS) is continued until the second imaging (step S8) is completed.

Here, in step S8, the test liquid 11 does not flow on the surface of the object to be inspected 10. Then, although the tracer slightly adheres to the surface of the object to be inspected 10, it does not move in the region to be imaged by the imaging unit 16 and does not become linear, and is hardly reflected in the original image.

Next, the detection unit 31 detects the scratched portion as a defect (step S9). The detection unit 31 performs predetermined image processing on the original image captured in the second imaging (step SS) to extract the magnetic particle instruction pattern. The detection unit 31 determines the presence or absence of a scratched portion based on the extracted magnetic particle instruction pattern, and detects the scratched portion. Then, the flaw detection is completed.

Here, since the detection of the scratched portion is performed based on the original image captured in a state where the test liquid 11 does not flow on the surface of the object 10 to be inspected, the tracer hardly appears in the original image. Therefore, even if the tracer is extracted as a candidate for a scratched portion, the region is small and it can be determined that the tracer is not a scratched portion. Further, only the magnetic powder instruction pattern can be extracted based on the difference in brightness between the light emitted by the tracer and the light emitted by the magnetic powder. Therefore, the tracer does not affect the detection of the scratched portion, and the inclusion of the tracer in the test solution 11 does not reduce the detection accuracy of the scratched portion.

The magnetic particle flaw detection method is not limited to the above method. The magnetic particle flaw detection method is appropriately changed according to the composition of the inspection liquid 11. For example, when the magnetic powder and tracer contained in the test liquid 11 are configured not to be excited by irradiation with ultraviolet rays, in the first irradiation with ultraviolet rays (step S2) and the second irradiation with ultraviolet rays (step S7), Irradiate visible light, for example white light, instead of ultraviolet light.

When the magnetic powder and the tracer contained in the test solution 11 are configured to emit light having different wavelengths, they are covered through the filter in the first imaging (step S3) and the second imaging (step S8). The surface of the inspection object 10 may be imaged. In the first imaging (step S3), a filter is used in which the light emitted by the tracer is transmitted and the light emitted by the magnetic powder is not transmitted. On the other hand, in the second imaging (step S8), a filter is used in which the light emitted by the magnetic powder is transmitted and the light emitted by the tracer is not transmitted. By adopting such a method, the calculation load of the control unit 30 by the detection unit 31 and the calculation unit 32 can be reduced, and the productivity can be improved. Further, the detection accuracy of the scratched portion and the measurement accuracy of the flow velocity and the flow direction of the test liquid 11 can be improved.

Further, the magnetization of the object to be inspected 10 (step S5) may be performed so that the magnetic particle instruction pattern is formed at the time of the second imaging (step S8), and the start and end times thereof are particularly limited. It's not a thing. For example, the magnetization of the object to be inspected 10 (step S5) may be started before the start of spraying the test solution (step S1), or may be terminated before the second imaging (step S8). I do not care. However, in order to prevent the formed magnetic particle instruction pattern from collapsing before the second imaging (step S8), the magnetization of the object 10 to be inspected (step S5) is completed in the second imaging (step S8). It is preferable to continue until it is done.

Further, the magnetic particle inspection method may be a step of irradiating one ultraviolet ray with the first irradiation of ultraviolet rays (step S2) and the second irradiation of ultraviolet rays (step S7). That is, the first irradiation of ultraviolet rays (step S2) may be continued until the second imaging (step S8) is completed. However, from the viewpoint of energy efficiency, it is preferable that the irradiation of ultraviolet rays is divided into a first irradiation of ultraviolet rays (step S2) and a second irradiation of ultraviolet rays (step S7).

Further, as the magnetic particle inspection method, as shown in FIG. 6, the first irradiation of ultraviolet rays (step S12) may be performed during the first imaging (step S13). Further, the second irradiation of ultraviolet rays (step S17) may be performed during the second imaging (step S18). Here, FIG. 6 is a flow chart showing an outline of another magnetic particle inspection method according to the present embodiment. In the magnetic particle inspection method shown in FIG. 5, another magnetic particle inspection method shown in FIG. 6 is a method in which step S2, step S3, step S7, and step S8 are different from each other in the magnetic particle inspection method shown in FIG. It is the same as the magnetic particle inspection method shown. The description of the part similar to the magnetic particle flaw detection method shown in FIG. 5 will be omitted.

In another magnetic particle inspection method, after the start of spraying the test solution 11 (step S1) is performed, the shutter of the imaging unit 16 is opened and the first imaging is started (step S13a). Then, while the imaging unit 16 opens the shutter, the first irradiation of ultraviolet rays (step S12) is performed. After the first irradiation of ultraviolet rays (step S12) is completed, the shutter of the imaging unit 16 is closed and the first imaging is completed (step S13b).

Similarly, after the spraying of the test solution 11 is stopped (step S6), the shutter of the imaging unit 16 is opened and the second imaging is started (step S18a). Then, while the imaging unit 16 opens the shutter, the second irradiation of ultraviolet rays (step S17) is performed. After the second irradiation of ultraviolet rays (step S17) is completed, the shutter of the imaging unit 16 is closed and the second imaging is completed (step S18b).

By adopting such a method, the irradiation time of the ultraviolet rays of the irradiation unit 15 can be minimized, and the irradiation unit 15 can be made inexpensive. Further, the irradiation unit 15 does not irradiate the ultraviolet rays that are unnecessary for the imaging of the imaging unit 16, and can irradiate the ultraviolet rays with high energy efficiency.

As described above, the magnetic particle flaw detection method according to the present embodiment includes a step of spraying the inspection liquid 11 containing magnetic powder on the object to be inspected 10, a step of irradiating the object to be inspected 10 with light, and light. A step of imaging the surface of the object to be inspected 10 to which the test liquid 11 is irradiated and the test liquid 11 flows, and a step of processing the captured original image to calculate the flow velocity and the flow direction of the test liquid 11 flowing through the surface. , The test liquid 11 further contains a tracer, and the tracer is a non-magnetic material, and when irradiated with light, emits light having a brightness or wavelength different from that emitted by magnetic powder.

Then, according to this embodiment, it is possible to provide a magnetic particle inspection method for easily measuring the flow velocity and the flow direction of the inspection liquid 11 flowing on the surface of the object to be inspected 10.

The present disclosure will be described in more detail and concretely with reference to Examples below. However, the present disclosure is not limited to the following examples.

<Material and measurement method>
[Example 1]
The magnetic particle flaw detection device 1 according to the present embodiment shown in FIGS. 1 to 3 and the magnetic particle flaw detection inspection liquid 11 according to the present embodiment were used. That is, the magnetic particle inspection device 1 has a spraying unit 13 that sprays the inspection liquid 11 on the object to be inspected 10, an irradiation unit 15 that irradiates the object to be inspected 10 with light, and an inspected unit that is irradiated with light and the inspection liquid 11 flows. An image pickup unit 16 that images the surface of an object 10 and a calculation unit 32 that processes an original image captured by the image pickup unit 16 and calculates the flow velocity and flow direction of the test solution 11 flowing on the surface of the test solution. No. 11 contained magnetic powder and a tracer, and the tracer was a non-magnetic material and had a feature that when irradiated with light, it emitted light having at least a brightness or wavelength different from the light emitted by the magnetic powder.

A non-magnetic tracer was produced by granulating a powder material containing a water-insoluble fluorescent pigment (manufactured by Shinroihi Co., Ltd .: Shinroihi Color FZ-6056M) as a main component. The tracer was prepared so that the particle size was about 50 μm to 100 μm and the fluorescence coefficient was about 70 cd / W. The prepared tracer and magnetic powder (manufactured by MARKTEC Corporation: Super Magna fluorescent magnetic powder, LY-30) were contained in water to prepare a test solution 11. The magnetic powder had a particle size of about 4.5 μm to 6.4 μm and a fluorescence coefficient of about 5.8 cd / W. The test solution 11 was prepared so that the magnetic powder concentration was about 0.5 g / L and the tracer concentration was about 300 pieces / mL. As the object to be inspected 10, a strip-shaped steel plate formed from SS400 was prepared. The object 10 to be inspected was formed in the shape of a gutter having a bottom having a width of about 210 mm, with both end portions bent upward. On the surface of the bottom of the object 10 to be inspected, a wound having a depth of about 0.12 mm, a length of about 30 mm, and a width of about 50 μm was formed. The wound portion extended in the width direction of the object to be inspected 10.

Then, the surface of the bottom surface of the object 10 to be inspected was detected by the magnetic particle flaw detection method shown in FIG. At this time, the strength of the magnetic field applied to the object 10 to be inspected by the magnetizing portion 12 was about 80 oersted. The flow rate of the test liquid 11 discharged from the spray nozzle 23 of the spray unit 13 was about 2 L / min. The intensity of the ultraviolet rays emitted by the irradiation unit 15 was about 4000 μW / cm ² at the center of the irradiation area on the bottom surface of the object 10 to be inspected. The light emitted when the magnetic powder and tracer of the test solution 11 were excited by ultraviolet rays was greenish yellow. The test liquid 11 was sprayed so as to flow in a film shape from one end to the other on the surface of the bottom of the object 10 to be inspected. The film thickness of the test solution 11 flowing on the surface of the bottom of the object 10 to be inspected was about 0.5 mm.

Further, as shown in FIG. 7, the time for applying the magnetic field from the magnetizing portion 12 to the object to be inspected 10 is 4.5 s, the time for spraying the test liquid 11 from the spraying portion 13 is 4 s, and the ultraviolet rays. The ultraviolet irradiation time of the irradiation unit 15 in the first irradiation and the second irradiation of ultraviolet rays was 10 ms, and the shutter speed of the image pickup unit 16 in the first imaging and the second imaging was 20 ms. Here, FIG. 7 is a time chart showing the operations of the magnetizing unit 12, the spraying unit 13, the irradiation unit 15, and the imaging unit 16, and shows a time chart for flaw detection of one inspected object 10.

Specifically, the imaging unit 16 opens the shutter 1 s after the inspection liquid 11 starts to be sprayed on the object 10 to be inspected by the spraying unit 13 to start the first imaging. The irradiation unit 15 irradiates ultraviolet rays 5 ms after the imaging unit 16 opens the shutter, and starts the first irradiation of the ultraviolet rays. Then, the irradiation unit 15 finishes the first irradiation of ultraviolet rays 5 ms before the shutter of the image pickup unit 16 is closed.

Further, the imaging unit 16 opens the shutter 2 seconds after the spraying unit 13 finishes spraying the test liquid 11, and starts the second imaging. The irradiation unit 15 irradiates ultraviolet rays 5 ms after the imaging unit 16 opens the shutter to start the second irradiation of the ultraviolet rays. Then, the irradiation unit 15 ends the second irradiation of ultraviolet rays 5 ms before the shutter of the image pickup unit 16 is closed. The magnetization of the object 10 to be inspected by the magnetizing portion 12 starts 2 seconds before the spraying of the inspection liquid 11 by the spraying portion 13 is completed.

Therefore, in the method according to the first embodiment, a step of spraying the test solution 11 containing magnetic powder on the test object 10, a step of irradiating the test object 10 with ultraviolet rays, and a step of irradiating the test object 10 with ultraviolet rays, the test liquid 11 flows. The test liquid 11 includes a step of imaging the surface of the bottom of the object to be inspected 10 and a step of processing the captured original image to calculate the flow velocity and the flow direction of the test liquid 11 flowing on the surface. The tracer had the characteristics according to the present embodiment, such as emitting light having a brightness different from that emitted by the magnetic powder when irradiated with ultraviolet rays.

[Example 2]
In the second embodiment, except for the configuration of the tracer and the imaging unit 11 contained in the test solution 11, the first imaging (step S13), and the second imaging (step S18) in the above-mentioned Example 1. It was the same as in Example 1.

The tracer of Example 2 was produced by granulating a powder material containing a water-insoluble fluorescent pigment (manufactured by Shinroihi Co., Ltd .: Shinroihi Color FZ-5037) as a main component. The tracer of Example 2 was made of a non-magnetic material, having a particle size of about 50 μm to 100 μm, and a fluorescence coefficient of about 15 cd / W. The prepared tracer and magnetic powder having a fluorescence coefficient of about 5.8 cd / W (manufactured by MARKTEC Corporation: Super Magna Fluorescent Magnetic Powder, LY-30) were contained in water to prepare a test solution 11. The test solution 11 of Example 2 was prepared so that the magnetic powder concentration was about 0.5 g / L and the tracer concentration was about 300 pieces / mL. The light emitted when the magnetic powder of the test solution 11 of Example 2 was excited by ultraviolet rays was greenish yellow. The light emitted when the tracer of the test solution 11 of Example 2 was excited by ultraviolet rays was red.

The imaging unit 16 of Example 2 is provided with a removable filter capable of transmitting light having a wavelength of 650 nm or more. When the image pickup unit 16 of Example 2 took an image through this filter, it could not take an image of the light emitted by the magnetic powder excited by the ultraviolet rays, and could take an image of the light emitted by the tracer excited by the ultraviolet rays.

In Example 2, in the magnetic particle inspection method shown in FIG. 6, in the first imaging (step S13), an image was taken through a filter, and in the second imaging (step S18), an image was taken with the filter removed. Then, the magnetic particle flaw detection method according to the second embodiment had the characteristics according to the present embodiment as in the first embodiment.

[Comparative Example 1]
In Comparative Example 1, the above-mentioned Example 1 was the same as that of Example 1 except for the configuration of the test solution 11. In Comparative Example 1, the test solution 11 did not contain a tracer. Therefore, the magnetic particle flaw detection method according to Comparative Example 1 did not have the characteristics according to the present embodiment.

[Comparative Example 2]
In Comparative Example 2, in Example 2 described above, the configuration was the same as in Example 2 except for the configuration of the test solution 11. In Comparative Example 2, the test solution 11 did not contain a tracer. Therefore, the magnetic particle flaw detection method according to Comparative Example 2 did not have the characteristics according to the present embodiment.

<Evaluation method>
(Measurement of flow velocity and flow direction of test solution 11)
For Example 1, Example 2, Comparative Example 1, and Comparative Example 2, the flow velocity and the flow direction of the test solution 11 were measured 50 times. In Example 1, the measured flow velocity is 230 mm / s to 500 mm / s, the average value thereof is 315.8 mm / s, and the measured flow directions are all substantially perpendicular to the width direction of the object 10 to be inspected. It was in the right direction. In Example 2, the measured flow velocity is 210 mm / s to 430 mm / s, the average value thereof is 319.5 mm / s, and the measured flow directions are all substantially perpendicular to the width direction of the object 10 to be inspected. It was in the right direction. In Comparative Example 1 and Comparative Example 2, since the test solution 11 did not contain a tracer, the flow velocity and the flow direction of the test solution 11 could not be measured.

(Detection of scratches)
For Example 1, Example 2, Comparative Example 1, and Comparative Example 2, the scratched portion of the object to be inspected 10 was detected. In Example 1, Example 2, Comparative Example 1, and Comparative Example 2, the scratched portion could be detected without over-detection.

The following points were derived from the above-mentioned examples. In Example 1 and Example 2, there was no significant difference between the average value of the flow velocity of the test liquid 11 flowing on the surface of the measured object 10 and the flow direction. The width of the bottom of the object to be inspected 10 is about 210 mm, the flow rate of the test solution 11 to be sprayed is about 2 L / min, and the film thickness of the test solution 11 flowing on the surface of the object to be inspected 10 is about 0. It is 5 mm. Therefore, the flow velocity of the test liquid 11 flowing on the surface of the object 10 to be inspected is estimated to be about 320 mm / s. In Examples 1 and 2, although there are variations in the flow velocity of the test liquid 11 flowing on the surface of the measured object 10, this variation is within a reasonable range, and the average value of the flow velocities is within a reasonable range. Was not far from this estimate. Further, in Examples 1 and 2, it was shown that the detection accuracy of the scratched portion does not decrease due to the inclusion of the tracer in the test solution 11.

From the results of the above examples, in the magnetic particle inspection device 1, the magnetic particle inspection method, and the magnetic particle inspection liquid 11 according to the present embodiment, the flow velocity and the flow direction of the inspection liquid flowing in a film shape on the surface of the object 10 to be inspected can be easily determined. It was shown that the detection accuracy of the wound was not reduced. Therefore, in the present embodiment, it is possible to provide a magnetic particle flaw detecting device 1, a magnetic particle flaw detecting method, and a magnetic particle flaw detecting inspection liquid 11 that can easily measure the flow velocity and the flow direction of the inspection liquid 11 flowing on the surface of the object to be inspected 10. It has been shown.

The present disclosure can be suitably used for a magnetic particle flaw detector that performs flaw detection using magnetic powder, a magnetic particle flaw detection method, and a magnetic particle flaw detection inspection liquid. However, the present disclosure is not limited to the embodiments and examples described above. The magnetic particle flaw detection device, magnetic particle flaw detection method, and magnetic particle flaw detection inspection liquid of the present disclosure are useful for flaw detection of the surface of any magnetic material such as shafts, pipes, steel materials, etc. It is useful when an inspector detects a flaw.

1 Magnetic particle inspection device 10 Object to be inspected 11 Magnetic particle inspection liquid (inspection liquid)
12 Magnetizing part 13 Spraying part 14 Recovery part 15 Irradiating part 16 Imaging part 30 Control part 31 Detection part 32 Calculation part

Claims (5)

A test solution containing magnetic powder and
A spraying part that sprays the test solution on the object to be inspected,
An irradiation unit that irradiates the object to be inspected with light,
An imaging unit that images the surface of the object to be inspected to which the light is irradiated and the inspection liquid flows.
A calculation unit that processes the original image captured by the imaging unit to calculate the flow velocity and flow direction of the test solution flowing on the surface.
With
The test solution further contains a tracer and
The tracer is a non-magnetic material, and when irradiated with the light, it emits light having at least a brightness or a wavelength different from the light emitted by the magnetic powder. The imaging unit is characterized by including a filter through which the light emitted by the tracer is transmitted and the light emitted by the magnetic powder is not transmitted.
The magnetic particle flaw detector according to claim 1. The irradiation unit irradiates a pulse of light, and the imaging unit images the surface in synchronization with the pulse irradiation by the irradiation unit.
The magnetic particle flaw detector according to claim 1 or 2. The irradiation unit irradiates ultraviolet rays and
The magnetic powder is excited by the ultraviolet rays to emit light.
The tracer is excited by the ultraviolet rays to emit light.
The magnetic particle flaw detector according to any one of claims 1 to 3. The process of spraying the inspection liquid containing magnetic powder on the object to be inspected,
The step of irradiating the object to be inspected with light and
A step of photographing the surface of the object to be inspected to which the light is irradiated and the inspection liquid flows,
A step of processing the captured original image to calculate the flow velocity and the flow direction of the test solution flowing on the surface, and
With
The test solution further contains a tracer and
The tracer is a non-magnetic material, and when irradiated with the light, it emits light having at least a brightness or wavelength different from the light emitted by the magnetic powder.

Images