Penetrant flaw detection method and penetrant flaw detection device

Abstract

To provide a penetrant flaw detection method and a penetrant flaw detection device capable of shortening the time required to complete an observation process on the same line.SOLUTION: A penetrant flaw detection method comprises a heating process 40, a penetrant process 31, a cooling process 41, a cleaning process 32, a developing process 33, an observation process 34, and other optional processes, where each step is completed within 2 minutes. A penetrant flaw detection device 1 that performs the penetrant flaw detection method includes, as heating means for the heating step 40, for example, a coil enabling high-frequency induction heating, and also includes a steam injection device 20 as cleaning means capable of performing the cleaning process 32, making it possible to inject superheated steam.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a penetrant inspection method and apparatus, and more particularly to a method of penetrantly infiltrating a flaw on the surface of an object to be inspected with a penetrant and then removing the penetrant, a method of observing the flaw, and an apparatus for carrying out these methods. [Background technology]

[0002] Penetrant testing has long been known as one of the non-destructive testing methods for detecting minute opening defects on the surfaces of products made of non-magnetic materials such as aluminum, titanium, stainless steel, and ceramics that are manufactured as industrial materials.

[0003] Penetrant testing is standardized in JIS Z2343-1 to 6. Conventionally known penetrant testing methods for penetrant testing include a penetrant step in which a penetrant is applied to the surface of the test object and the penetrant is allowed to penetrate into the open defects present on the surface of the test object, a cleaning step in which the excess penetrant that has not penetrated into the defects and remains on the surface of the test object is removed by a cleaning solution so that the penetrant remains only in the defects, a development step in which a uniform thin layer of developer is formed on the surface of the test object after the cleaning solution has dried, the penetrant that has penetrated into the defects is sucked out to reveal a defect indication pattern on the layer surface, and an observation step in which the defect indication pattern is confirmed under irradiation with visible light or ultraviolet light. If the surface of the test object has oil stains or the like before the penetrant step, a pretreatment step is performed to clean the surface using an organic solvent or the like. The penetrant is usually a non-volatile, highly penetrating liquid obtained by dissolving a red dye or a fluorescent dye in a petroleum-based mixed solvent, an aromatic solvent, or the like, and adding a plasticizer, a surfactant, or the like. Also, a method is known in which an organic solvent capable of dissolving the penetrant or water is used as a cleaning liquid for cleaning away the excess penetrant.

[0004] Patent Document 1 discloses a penetrant inspection method in which a cleaning operation is performed in which excess penetrant remaining on the surface of the test object is turned into fine oil droplets and removed by spraying steam onto the surface of the test object using a high-pressure jet in a penetrant inspection test. This technology is superior in that it uses steam, but the steam is thought to contain moisture, so there is room for reducing the amount of wastewater and the drying time can be long.

[0005] Patent Document 2 discloses a penetrant testing method in which the heating of the surface of a test specimen in the drying process carried out after a cleaning process in which excess penetrant is washed away with water is performed by induction heating, in which self-heating is caused by the resistance loss of eddy currents induced near the surface layer of the test specimen. Although this is an excellent drying process, there are still problems with shortening the time required for the process of penetrating the penetrant.

[0006] In addition, in the case of Patent Documents 1 and 2, although the formation of the indication pattern by the penetrant in the development process can be promoted, when only one of the penetrant process or the indication pattern formation process (drying and observation process) is shortened, for example, when the penetrant process and the drying and observation process are carried out on the same line such as a merry-go-round type rotary conveyance, the time of the slower process must be adjusted, so that there is a problem in that the time cannot be shortened after all.

[0007] [Patent Document 1] Japanese Patent Application Publication No. 52-146291 [Patent Document 2] Japanese Patent Application Publication No. 6-167462 Summary of the Invention [Problem to be solved by the invention]

[0008] The conventionally known penetrant inspection method is a test that requires a relatively long time among the flaw detection tests. Therefore, it has been an issue whether the time required for this can be shortened. More specifically, in the conventionally known penetrant inspection method, in the penetration step in which the penetrant is made to penetrate into the open defect part present on the surface of the test object, a long penetration time is required to allow the penetrant to penetrate into the open defect part sufficiently. The long penetration time in the penetration step causes the penetrant step to become a bottleneck, reducing the work efficiency of the line, and the need for a large space for the penetrant step. In addition, it has been an issue whether it is possible to move to the observation step in a short time after the cleaning step, and whether it is possible to complete the observation step in a shorter time because the conventional method of observing after the flaw grows takes too much time in the observation step. In addition, it has been an issue that a large space is required for the penetrant inspection because the time required for the penetrant inspection is long.

[0009] In particular, when the test object is a relatively large billet, storage space is required to wait for the growth of the indication pattern on multiple billets, and factories with high production volumes need to secure a large space to store many large billets, which is also an issue. Therefore, the conventional penetrant inspection method is practically unable to target parts with high production volumes or parts that must be inspected in real time. In addition, using water in the cleaning process is safe and does not pose the risk of inhalation toxicity or ignition. However, using water also causes water contamination, which places a heavy burden on wastewater treatment, which is also an issue.

[0010] In addition, by simply shortening either the penetration process or the cleaning-observation process, the other process that takes a long time becomes a bottleneck in one line, for example, when a merry-go-round type rotary conveyance is used, and sufficient time reduction is not achieved. When using rotary conveyance, all processes run simultaneously, so if there is a process that takes a long time to process, it is necessary to lengthen the cycle time or increase the number of processes to adjust the time. Increasing the number of processes increases the size of the penetrant inspection device itself, and there is also the problem that it is not possible to make a compact penetrant inspection device. The present invention provides a penetrant inspection method and a penetrant inspection device used therefor to solve these problems. [Means for solving the problem]

[0011] The penetrant flaw detection apparatus of the present invention is a penetrant flaw detection apparatus comprising an apparatus for carrying out a penetrating process of applying a penetrating liquid to the surface of the object to be inspected, a cleaning apparatus for carrying out a cleaning process of removing the penetrating liquid from the surface of the object to be inspected, and an apparatus for carrying out an observation process of observing an indication pattern, wherein the penetrant flaw detection apparatus further comprises a heating apparatus for carrying out a heating process before the penetrating process, the heating apparatus being capable of heating the surface of the object to be inspected by 30 degrees or more in absolute temperature, the cleaning apparatus being configured to be capable of injecting superheated steam from the nozzle of the steam injection device onto the surface of the object to be inspected, the penetrant flaw detection apparatus further comprises a transport device, and the penetrant flaw detection apparatus comprises one or more handling devices for fixing the object to be inspected, the transport device forms a line, and loading and unloading can be carried out in the same area on the line.

[0012] In addition, in the present invention, the penetrant flaw detection apparatus is characterized in that the conveying device is a merry-go-round type rotary conveying device.

[0013] Furthermore, in the present invention, the penetrant flaw detection device is characterized by including a wireless power supply system and a wireless LAN communication system.

[0014] Further, the penetrant inspection method of the present invention sequentially comprises a penetrant step of applying a penetrant liquid to an object to be inspected, a cleaning step of removing the penetrant liquid from the surface of the object to be inspected, and an observation step of observing an indication pattern, and further comprises a heating step before the penetrant step, and in addition to the heating step, the penetrant inspection method further comprises a cooling step immediately after the penetrant step to allow the penetrant liquid to penetrate, a drying step to dry the water wetted in the cleaning step, a carrying-out and carrying-in step, and any other optional steps. The method is characterized in that the heating step, the penetration step, the cleaning step, the observation step, and the optional cooling step, the drying step, the carrying-in and carrying-out steps, and other steps, which are provided in the penetrant flaw detection method, are all completed within 2 minutes, the heating step is a step of heating the surface of the object to 30 degrees or more in absolute temperature, and the cleaning step is a step of cleaning the surface of the object to be inspected by injecting steam from a steam injection device, and the steam injected by the steam injection device is superheated steam.

[0015] In addition, in the present invention, the penetrant flaw detection method further includes a cooling step after the penetrating step is completed and before the cleaning step is started, and the cooling step is started within 30 seconds after the penetrating step is completed. Effect of the Invention

[0016] The penetrant inspection apparatus of the present invention is provided with a penetrant step of applying a penetrant liquid to the surface of the object to be inspected, a cleaning device for performing a cleaning step of removing the penetrant liquid from the surface of the object to be inspected, and a device for performing an observation step of observing an indication pattern. The penetrant inspection apparatus further includes a heating device for performing a heating step before the penetrant step, the heating device being capable of heating the surface of the object to be inspected by 30 degrees or more in absolute temperature, and the cleaning device being configured to be able to spray superheated steam from the nozzle of the steam injection device onto the surface of the object to be inspected. The penetrant inspection apparatus further includes a conveying device. The penetrant inspection apparatus further includes one or more handling devices for fixing the object to be inspected, the conveying device forms a line, and the carrying-in and carrying-out can be performed in the same area on the line. Therefore, the penetrant liquid can be penetrated into the open defect in a short time, and the penetrant liquid can be effectively removed in the cleaning step while the growth of the indication pattern can be accelerated. This makes it possible to shorten the cycle time and to provide a penetrant inspection method that reduces the load on wastewater treatment in the cleaning step.

[0017] In addition, in the present invention, the penetrant flaw detection device is characterized in that the conveying device uses a merry-go-round type rotating conveying device, so that a penetrant flaw detection device can be provided that can penetrate the penetrant into the open defect in a short period of time, and can effectively remove the penetrant in the cleaning process while accelerating the growth of the indication pattern.

[0018] In addition, in the present invention, the penetrant flaw detection device is characterized by being equipped with a wireless power supply system and a wireless LAN communication system, so that a penetrant flaw detection device can be provided that eliminates the hassle of maintenance even when transported by a rotating transport device.

[0019] Furthermore, the penetrant inspection method of the present invention is a penetrant inspection method which sequentially comprises a penetrant step of applying a penetrant to an object to be inspected, a cleaning step of removing the penetrant from the surface of the object to be inspected, and an observation step of observing an indication pattern, and further comprises a heating step before the penetrant step, and the penetrant inspection method, in addition to the heating step, penetrant step, cleaning step, and observation step, optionally comprises a cooling step immediately after the penetrant step to allow the penetrant to penetrate, a drying step to dry water wetted in the cleaning step, a carrying-out and carrying-in step, and other optional steps, and the heating step, penetrant step, cleaning step, and observation step, as well as the optional cooling step, drying step, carrying-out and carrying-in steps, which are included in the penetrant inspection method, are Each of the steps, including the loading process and other steps, can be completed within two minutes. The heating process is a process of heating the surface of the object to be inspected to 30 degrees or more in absolute temperature. The cleaning process is a process of cleaning the surface of the object to be inspected by injecting steam from a steam injection device. The steam injected by the steam injection device is superheated steam. Since the penetrant can penetrate into the open defect in a short period of time, and the penetrant can be effectively removed in the cleaning process while accelerating the growth of the indication pattern, the cycle time can be shortened, and a penetrant flaw detection method can be provided that reduces the burden on wastewater treatment in the cleaning process.

[0020] Furthermore, the penetrant flaw detection method of the present invention is characterized in that it further includes a cooling step after the penetration step is completed and before the cleaning step is started, and the cooling step is started within 30 seconds after the penetration step is completed, so that a penetrant flaw detection method can be provided that can penetrate the penetrant liquid into the open defect in a short period of time. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a flowchart of a conventional penetrant inspection method. [Diagram 2]1A and 1B are schematic cross-sectional views showing the transition of the state around the flaw 12 in a conventional penetrant inspection method, in which (W) is the state before the penetrating process 31 is performed, (X) is the state immediately after the penetrating liquid 21 is applied to the flaw 12 during the penetrating process 31, (Y) is the state around the flaw 12 when the penetrating time has elapsed from the state (X) during the penetrating process 31, and (Z) is a schematic diagram showing the state around the flaw 12 after the cleaning process 32'. [Diagram 3] FIG. 2 is a flowchart of a penetrant inspection method according to the present embodiment. [Figure 4] 11 is a schematic cross-sectional view showing the transition of the state around the flaw 12 in the penetrant inspection method of this embodiment, in which (W) is the state before the penetrant process 31 is performed, (X) is the state immediately after the penetrant liquid 21 is applied to the flaw 12 during the penetrant process 31, (Y) is the state around the flaw 12 when the penetrant time has elapsed from the state (X) during the penetrant process 31, and (Z) is a schematic diagram showing the state around the flaw 12 after the cleaning process 32. [Diagram 5] 3 is a schematic diagram showing the state around a flaw 12 when a cleaning step 32 is performed in the penetrant inspection method according to the present embodiment. FIG. [Figure 6] FIG. 1 is a schematic diagram mainly showing the flaw 12 and the first automatic imaging device 24, and FIG. 2 is a schematic diagram mainly showing the flaw 12' and the second imaging device 25 when performing the observation process 34 in the penetrant flaw detection device 1 and the penetrant flaw detection method of this embodiment. [Figure 7] 1 is a flow chart of the penetrant flaw detector 1 according to the present embodiment, and is also a conceptual diagram showing the layout of areas. [Figure 8] FIG. 8 is a schematic perspective view showing the penetrant flaw detector 1 of FIG. 7. [Figure 9] FIG. 11 is a conceptual diagram showing the flow and area arrangement of a penetrant flaw detector as another example according to the present embodiment. [Figure 10] 1 is a front view showing a handling device 110 provided in the penetrant flaw detection device 1 of this embodiment, in which (X) shows the state in which the object to be inspected 10 is lowered, and (Y) shows the state in which the object to be inspected 10 is raised. [Figure 11]FIG. 1 is a front view showing the handling device 110 provided in the penetrant flaw detection device 1 of this embodiment, in which (X) is the base, (Y) shows a rotation of about 45 degrees around the cylinder portion 111 as an axis, and (Z) shows a rotation of about 45 degrees in the opposite direction. [Figure 12] This is a top view showing the handling device 110 equipped with the penetrant flaw detection device 1 of this embodiment, in which (X) is the base, (Y) shows a rotation of about 45 degrees around the cylinder portion 111 as an axis, and (Z) shows a rotation of about 45 degrees in the opposite direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, the details of the embodiment of the present invention will be described with reference to the drawings. First, the penetrant inspection method according to the present embodiment will be described. FIG. 1 is a flow chart of a conventional penetrant inspection method. FIG. 2 is a schematic cross-sectional view showing the transition of the state around the flaw 12 in the conventional penetrant inspection method, where the state transitions in the order of (W), (X), (Y), and (Z). Of these, (W) represents the initial state before the penetrant step 31 is performed. (X) represents the state immediately after the application of the penetrant to the flaw 12 in the penetrant step 31, (Y) represents the state around the flaw 12 when the penetrant time has elapsed from the state of (X) in the penetrant step 31, and (Z) represents the state around the flaw 12 after the cleaning step 32'. FIG. 3 is a flow chart of a penetrant inspection method as an example of an embodiment according to the present invention. FIG. 4 is a schematic cross-sectional view showing the transition of the state around the flaw 12 in the penetrant inspection method according to the present embodiment, where the state transitions in the order of (W), (X), (Y), and (Z). Among them, (W) represents the initial state before the penetration step 31 is performed. (X) represents the state immediately after the application of the penetrant to the flaw 12 in the penetration step 31, (Y) represents the state around the flaw 12 when a shorter penetration time than the conventional time has elapsed from the state of (X) in the penetration step 31, and (Z) represents the state around the flaw 12 after the cleaning step 32. FIG. 5 is a schematic diagram showing the state around the flaw 12 during the cleaning step 32 in the penetrant flaw inspection device and the penetrant flaw inspection method according to this embodiment. FIG. 6 is a schematic diagram showing the transition of the flaw 12 when the observation step 34 is performed in the penetrant flaw inspection device 1 and the penetrant flaw inspection method according to this embodiment, and shows that the state of the flaw 12 transitions to the state of the flaw 12' in the order of (X) and (Y). FIG. 7 is a schematic diagram showing the layout of the area in a circle and the flow of the method of transporting the test object in the penetrant flaw inspection method and the penetrant flaw inspection device 1 according to this embodiment because of the rotational transport. Fig. 8 is a schematic perspective view showing the penetrant flaw detection device 1 of Fig. 7. Supports for power supply and the like are omitted from Fig. 8. Fig. 9 is a schematic view showing the penetrant flaw detection method and penetrant flaw detection device according to the present embodiment in a circular manner, as in Fig. 7, and illustrating the layout of the areas and the flow of the method of transporting the test object due to the rotational transport.FIG. 10 is a front view showing the handling device 110 provided in the penetrant inspection device 1 of this embodiment, where (X) shows the state in which the test object 10 is lowered, and (Y) shows the state in which the test object 10 is raised. FIG. 11 is a front view showing the handling device 110 provided in the penetrant inspection device 1 of this embodiment, where (X) is the reference, (Y) shows the cylinder part 111 rotated about 45 degrees around the axis, and (Z) shows the reverse rotation of about 45 degrees. FIG. 12 is a top view showing the handling device 110 provided in the penetrant inspection device 1 of this embodiment, where (X) is the reference, (Y) shows the cylinder part 111 rotated about 45 degrees around the axis, and (Z) shows the reverse rotation of about 45 degrees. FIGS. 12(X), (Y), and (Z) show the top views of FIGS. 11(X), (Y), and (Z), respectively. In this disclosure, for the sake of convenience, when simply referring to the upper side, it refers to the upper side in FIGS. 2, 4, 5, and 6, and when simply referring to the lower side, it refers to the lower side in FIGS.

[0023] The steps shown in FIG. 1 are a flow chart showing the steps of a conventional penetrant inspection method. In the conventional penetrant inspection method, a penetrant step 31, a cleaning step 32', a developing step 33, and an observation step 34' are sequentially performed. This will be described in detail with reference to the state around the flaw 12 shown in FIG. 2. Each of (W) to (Z) in FIG. 2 is a cross-sectional view showing an enlarged view of the flaw 12, which is a target for detection in the penetrant inspection method, on the inspection object 10. First, FIG. 2(W) shows the state before the penetrant step 31 shown in FIG. 1. In the state shown in FIG. 2(W), the flaw 12 has a defect opening 13 and a defect interior 14. The flaw 12 is formed in a shape having the defect opening 13 on the surface 11, which is the surface of the inspection object 10.

[0024] Next, the penetrating step 31 shown in Fig. 1 will be described in detail. The penetrating step 31 is performed by applying the penetrating liquid 21 to the surface 11 of the object to be inspected 10. Methods of application include coating, immersion in the penetrating liquid, etc. The penetrating liquid 21 may be a liquid having a composition in which a fluorescent dye or a red visible dye is dissolved in an oily solvent and a surfactant is further added to the liquid to make it removable by washing with water, or a liquid in which a fluorescent dye or a red visible dye is dissolved in an oily solvent.

[0025] FIG. 2(X) shows the state immediately after the penetrant 21 is applied to the surface 11 in the penetrant step 31. Since the penetrant 21 is applied to the surface 11 immediately, the penetrant 21 has not yet penetrated into the defect interior 14, which is the inside of the flaw 12. In the conventional penetrant inspection method, the penetrant 21 does not penetrate sufficiently into the defect interior 14 from the defect opening 13 unless a certain long penetration time is passed after the penetrant step 31. FIG. 2(Y) shows the state after the long penetration time has passed. In FIG. 2(Y), the penetrant 21 has sufficiently penetrated and penetrated into the defect interior 14. However, since the penetrant 21 covers the surface 11, it is necessary to remove the penetrant 21 from the surface 11 by the cleaning step 32' shown in FIG. 1. Therefore, in the cleaning step 32', the cleaning liquid is applied to the surface 11 from, for example, the direction of the arrow in FIG. 2(Y) so as to wash away the penetrant 21. This causes a transition from the state of FIG. 2(Y) to the state of FIG. 2(Z).

[0026] Next, the state of Fig. 2(Z) will be described in detail. The state of Fig. 2(Z) is a state in which the penetrant liquid 21 that filled the surface 11 of the inspection object 10 has been washed away with a cleaning liquid in the cleaning step 32', and the penetrant liquid 21 has been removed. Although the penetrant liquid 21 has been removed from the surface 11, the penetrant liquid 21 remains inside the defect 14 as it has penetrated therein.

[0027] Next, the developing step 33 will be described. First, in the state shown in FIG. 2(Z), the penetrant 21 remains only inside the defect 14. In this state, the flaw 12 is so fine that the presence of the penetrant 21 is difficult to detect with the naked eye. Therefore, a white inorganic fine powder or a dispersion of the white inorganic fine powder in water or a solvent is applied to the surface 11 as a developer so as to form a uniform thin layer on the test object. Examples of the white inorganic fine powder include magnesium carbonate powder and calcium carbonate powder. Then, the uniform thin layer of the white inorganic fine powder formed on the surface 11 causes a capillary phenomenon, sucking out the penetrant 21 inside the defect 14, thereby forming a rainbow pattern (defect indication pattern). This defect indication pattern shows the defect opening 13 in an enlarged manner, making it easy to detect with the naked eye.

[0028] As for the observation step 34', in addition to visual observation, the indication pattern is observed using a method in which a fluorescent penetrant is used and then a black light is used in a dark room, or an image is generated using an imaging device or the like and then inspected.

[0029] Next, the penetrant inspection method according to the present invention and the penetrant inspection device 1 using this method will be described in detail with reference to Figs. 3 and 4. The steps shown in Fig. 3 are a flow chart showing steps of the penetrant inspection method as an example of an embodiment according to the present invention. Fig. 4 is a cross-sectional view showing an enlarged view of the periphery of a flaw 12, which is a detection target in the penetrant inspection method, on an object 10 in each of Figs. (W) to (Z). Unlike the conventional method, the penetrant inspection method according to the present embodiment includes a heating step 40 shown in Fig. 3. In the heating step 40, heating is performed toward the surface 11 shown in Fig. 4(X) by a heating means. The heating means may be a method using high-frequency induction heating, a method using steam or dry steam, a method using hot air, or a method using infrared heating, or other known means may be used. By heating the surface 11 and the surface vicinity 16 by the heating means, the air inside the defect 14 expands, making it easier to draw in the penetrant liquid 21.

[0030] The penetrant inspection method according to an embodiment of the present invention will be described in more detail with reference to Figs. 3 and 4. The penetrant inspection method according to an embodiment of the present invention shown in Fig. 3 is a method in which a heating step 40, a penetrant step 31, a cooling step 41, a cleaning step 32, a developing step 33, and an observation step 34 are sequentially performed. In this manner, the penetrant inspection method according to this embodiment first performs the heating step 40. In the heating step 40, the surface 11 is heated by a heating means in the initial state shown in Fig. 4(W), and then the penetrant step 31 is performed. In the heating step, it is preferable to heat the surface 11 to an absolute temperature of 30 degrees Celsius or more. This means that the penetrant inspection is usually performed at room temperature, and therefore the surface 11 is heated to 30 degrees Celsius or more. By heating in this manner, the penetrant time is significantly reduced.

[0031] In this disclosure, the penetration time refers to the time required from the end of the process of applying the penetrant liquid 21 to the surface 11 of the object to be inspected 10 in the penetration step 31 until the penetrant liquid 21 has sufficiently penetrated into the interior 14 of the defect for penetrant testing and the state becomes ready for moving on to the next cleaning step 32, 32'.

[0032] In the heating step 40, it is preferable to raise the absolute temperature of the surface 11 by 30 degrees Celsius or more, and it is even more preferable to raise the absolute temperature of the surface 11 by 50 degrees Celsius or more by the heating means. When the absolute temperature of the surface 11 is raised by the heating means by 50 degrees Celsius or more in this manner, it is preferable that the penetrant liquid 21 can penetrate into the defect interior 14 to such an extent that a relatively large flaw of about 10 to 50 microns in size can be detected in a penetration time of about 5 to 10 seconds in a penetrant inspection test. As will be described later, the heating step 40 is performed in a heating step area 140. In order to perform the heating step 40, it is preferable to provide a plurality of temperature sensors in the heating step area 140. In the heating step 40, it is preferable to control the handling device and the heating means based on the information from the temperature sensors, thereby achieving a uniform temperature rise at all the points set on the surface of the test object. As the member used for the temperature sensor, a known means such as a non-contact radiation thermometer may be used.

[0033] The penetrant step 31 in the penetrant inspection method according to this embodiment shown in Fig. 3 is performed by applying the penetrant liquid 21 to the surface 11 of the object 10 to be inspected. This results in a transition to the state shown in Fig. 4(X). The penetrant liquid 21 may be applied by a known method such as application by spraying or immersion in a penetrant liquid tank. Examples of the penetrant liquid 21 include a liquid having a composition in which a fluorescent dye or a red visible dye is dissolved in an oily solvent and a surfactant is further added to the liquid to make it removable by washing with water, or a liquid in which a fluorescent dye or a red visible dye is dissolved in an oily solvent, but other known liquids may also be used.

[0034] In the penetration step 31, after the penetrant liquid 21 is applied, the penetrant liquid 21 is left attached to the surface 11 and the cleaning step 32 is not started until the penetration time has elapsed. This allows the penetrant liquid 21 to penetrate into the defect interior 14. By going through the heating step 40 of the penetrant flaw detection method according to the present embodiment, this penetration time can be made shorter than usual. Specifically, what previously required 5 to 10 minutes or more is reduced to about 5 to 15 seconds. It is preferable to carry out the heating step 40 because the penetrant liquid 21 can be sufficiently penetrated into the defect interior 14 even if the penetration time is shortened.

[0035] Next, the cooling step 41 shown in FIG. 3 will be described in detail. The cooling step 41 is preferably performed during the permeation time after the permeation liquid 21 is applied to the object 10 in the permeation step 31. The permeation step 31 is performed by applying the permeation liquid 21 to the object 10 to cover the surface 11 of the object 10 to be inspected. The permeation step 31 is completed when the application of the permeation liquid 21 to the object 10 to be inspected is completed. The permeation time is the time required for the permeation of the permeation liquid into the object 10 after the permeation step 31 is completed. The timing for starting the cooling step 41 is preferably within 30 seconds after the permeation step 31 is completed, and more preferably within 10 seconds after the permeation step 31 is completed. However, the cooling step 41 may not be provided. In that case, as another example of this embodiment, a permeation time may be provided between the permeation step 31 and the cleaning step 32 such that the cooling step 41 is not performed. Specifically, the cooling step 41 is performed after the infiltration step 31 by blowing cold air or pouring room temperature water or cold water toward the vicinity of the surface 11 to which the infiltrate 21 is attached in the state of (X) in FIG. 4. This generates a cooling effect that cools the surface 11 and the surface vicinity 16. Due to the cooling effect, the air inside the defect 14 is also cooled and contracts. As a result, the infiltrate 21 is drawn into the defect 14.

[0036] In particular, when the cooling step 41 is performed by pouring room temperature water or cold water onto the object 10 to be inspected or by immersing the object 10 in room temperature water or cold water, the cooling step 41 may be performed immediately after the penetration step 31, and the temperature of the surface of the object 10 to be inspected is rapidly cooled. By cooling in this manner, the air inside the defect 14 is also rapidly cooled and contracts. This makes it more preferable that the effect of drawing the penetrant 21 into the defect 14 is greater than the effect of cooling by leaving the object at room temperature. By carrying out the cooling step 41, such a cooling effect occurs, and therefore it is possible to shorten the penetration time from the cooling step 41 until moving to the cleaning step 32. As causes of the cooling effect that cools the vicinity of the surface 11 and the surface vicinity portion 16, cooling from the inside portion of the test object 10 and cooling by the penetrating liquid 21 are also important.

[0037] Next, the cleaning step 32 shown in FIG. 3 and FIG. 4(Y) will be described. In the cleaning step 32, as shown in FIG. 4(Y), the penetrant 21 has sufficiently penetrated into the defect interior 14 from the defect opening 13. In other words, the penetrant 21 has sufficiently penetrated into the defect interior 14. However, the penetrant 21 covers the surface 11, so it is necessary to remove it. For this reason, the penetrant 21 is removed from the surface 11 by the cleaning step 32 shown in FIG. 3. For this reason, the penetrant flaw detection device 1 according to this embodiment is provided with a cleaning means. The cleaning means includes a steam injection device 20 and a suction recovery unit 22. The suction recovery unit 22 is not shown in FIG. 4(Y) and (Z). In the cleaning step 32, a method is used in which the cleaning liquid is injected from the steam injection device 20 in FIG. 4(Y) as superheated steam toward the surface 11 to remove the penetrant 21. By carrying out this, the state of FIG. 4(Y) transitions to the state of FIG. 4(Z).

[0038] Next, the developing step 33 will be described. First, the state in FIG. 4(Z) is a state in which the cleaning step 32 is completed and the penetrant 21 remains only inside the defect 14. In this state, the presence of the penetrant 21 is difficult to detect with the naked eye. Therefore, as a developer, a white inorganic fine powder or a powder obtained by dispersing the white inorganic fine powder in water or a solvent is applied to the surface 11 so as to form a uniform thin layer on the test object. As the white inorganic fine powder, a powder known to be used as a developer, such as magnesium carbonate powder or calcium carbonate powder, may be used. Then, the uniform thin layer of the white inorganic fine powder formed on the surface 11 causes a capillary phenomenon, sucking out the penetrant 21 inside the defect 14, thereby forming a rainbow pattern (defect indication pattern). This defect indication pattern shows the defect opening 13 in an enlarged manner, making it easier to detect with the naked eye and improving the detection accuracy.

[0039] However, the penetrant inspection method of the present invention may be performed by a known method such as a non-developing method without the development step 33. In the case of the non-developing method, the development step 33 is not performed to apply a developer, and the indication pattern of the penetrant is observed as is. For this reason, it is preferable to use a fluorescent penetrant from the viewpoint of convenience of observation in the observation step 34, but the present invention is not limited to this.

[0040] As for the observation step 34 shown in FIG. 3, the indication pattern can be observed by visual inspection or by using known means such as a method of using a fluorescent penetrant in a dark room with a black light, or a method of generating an image using an imaging device and inspecting it.

[0041] FIG. 5 shows an example of the penetrant inspection method and penetrant inspection device 1 according to the present embodiment, for carrying out the cleaning step 32. The steam injection device 20 injects superheated steam in the direction of the arrow α toward the surface 11 of the test object 10 from the upper right direction. Then, the superheated steam hits the penetrant 21, mixes with the condensed water, turns into fine oil droplets, and the penetrant 21 turns into mist, or the superheated steam condenses into water, mixes with the penetrant 21, and flows down. It is preferable to use superheated steam that has a temperature of 110 degrees Celsius or more immediately after being injected from the nozzle of the steam injection device 20. It is also preferable that the pressure of the superheated steam inside the nozzle of the steam injection device 20 is 0.1 to 1.0 megapascals. If the pressure is lower than 0.1 MPa, the penetrant 21 cannot be effectively removed, and if the pressure exceeds 1.0 MPa, when a fluorescent penetrant is used as the penetrant 21, the fluorescent brightness of the fluorescent penetrant decreases, and there is a risk of the pattern being overlooked. The cleaning process 32 is preferably performed in a booth surrounded by a shielding plate so that the mist of the penetrant 21 does not scatter, but this is not a limitation. Also, when the cleaning process is performed in a booth, a suction recovery section may not be provided because the penetrant does not scatter to the outside.

[0042] Furthermore, it is more preferable that the temperature of the superheated steam injected by the steam injection device 20 immediately after being injected from the injection port of the nozzle provided in the steam injection device 20 is 130 degrees Celsius or more and 180 degrees Celsius or less. At 130 degrees Celsius, there is a 30 degree margin before condensation begins, so that the amount of water that condenses when the superheated steam is sprayed onto the surface 11 and becomes waste water can be reduced, and the drying of the surface 11 can be accelerated. This is preferable because the drying of the surface 11 does not hinder the growth of the so-called indication pattern, in which the penetrant 21 oozes out of the flaw 12 and forms an indication pattern. Furthermore, if the superheated steam exceeds 180 degrees Celsius, when a fluorescent penetrant is used as the penetrant 21, the fluorescent substance contained in the fluorescent penetrant is an organic substance, and there is a risk of the composition changing or the quality deteriorating.

[0043] As shown in FIG. 5, the opening of the suction recovery unit 22 is provided in the direction of the arrow β, which is the direction in which the superheated steam incident from the direction α is reflected. The suction recovery unit 22 is composed of an opening, a pipe, and a suction recovery means, and the suction recovery means may be a known means such as a mist collector or a local exhaust device combined with a filter. The suction recovery unit 22 may also be equipped with a ventilator 23. If a motor is used to configure the suction recovery means, there is a risk of malfunction when high-temperature mist is sucked. Therefore, in addition to suction from the opening in the β direction, the ventilator 23 also takes in gas from the ventilator 23, which is preferable because it can lower the temperature of the sucked gas when it reaches the suction recovery means. The ventilator 23 may be equipped with a damper with an adjustable air volume (not shown). This damper with an adjustable air volume is preferable because it can adjust the temperature inside the pipe of the suction recovery means 22.

[0044] Next, the observation step 34 in the penetrant inspection method and penetrant inspection device 1 according to this embodiment will be described in more detail with reference to Fig. 6. After the cleaning step 32 shown in Fig. 5 is completed, the test object 10 reaches the observation means in the observation step area 134 of the penetrant inspection device 1. As the observation means, Fig. 6 shows a configuration including a first automatic imaging device 24 capable of capturing still images and a second automatic imaging device 25 also capable of capturing still images, but a configuration including a third automatic imaging device capable of capturing moving images may also be used. Fig. 6 shows a flaw 12 and a flaw 12', but the flaw 12' is shown as the flaw that has undergone a state transition when the flaw 12 moves in the traveling direction.

[0045] With reference to FIG. 6, the case where the observation step 34 is started by using a non-developing method after the cleaning step 32 is completed will be described in more detail. The penetrant flaw detection device 1 and the penetrant flaw detection method according to the present invention are provided with the first automatic imaging device 24 and the second automatic imaging device 25, or the third automatic imaging device, as an observation means. After the cleaning step 32 is completed, the first automatic imaging device 24 starts imaging or the third automatic imaging device starts imaging a moving image in the observation step 34, between 1 second and 20 seconds. FIG. 6(X) shows the state of imaging by the first automatic imaging device 24, and FIG. 6(Y) shows the state of imaging by the second automatic imaging device 25. The process may be changed from the state of FIG. 6(X) to the state of FIG. 6(Y). First, the surface part of the inspection object 10 cleaned in the cleaning step 32 enters the imaging range of the first automatic imaging device 24, which can capture still images. Then, the portion of the surface of the object 10 cleaned in the cleaning step 32 reaches the imaging range 26 of the first automatic imaging device 24 shown in Fig. 6(X) one second after the completion of the cleaning step 32, and reaches the imaging range 26' of the second automatic imaging device 25 shown in Fig. 6(Y) by 20 seconds after the completion of the cleaning step 32, and is imaged by the second automatic imaging device 25. However, from the viewpoint of time saving, it is fully possible and preferable to perform this within 1 to 10 seconds from the completion of the cleaning step 32.

[0046] The first automatic imaging device 24 and the second automatic imaging device 25 capture images at regular intervals. It is preferable to leave a predetermined interval between the first automatic imaging device 24 and the second automatic imaging device 25 after a specific part enters the imaging range 26 and before it enters the next imaging range 26', because this makes it possible to observe the growth of the indication pattern and distinguish pseudo patterns, etc., using the first and second automatic imaging devices.

[0047] In the case of capturing a moving image by the third automatic imaging device, the portion of the surface of the object 10 cleaned in the cleaning step 32 reaches the imaging range of the third automatic imaging device one second after the completion of the cleaning step 32, and the portion of the surface of the object 10 cleaned in the cleaning step 32 is imaged for a predetermined length of time. By capturing images in this manner, the growth of the indication pattern can be captured and a false pattern or the like can be distinguished, which is preferable.

[0048] Next, referring to FIG. 6, the penetrant flaw detection method and penetrant flaw detection device 1 according to the present embodiment will be described in detail with a focus on the state of the flaw 12. The flaw 12 shown in FIG. 6(X) has reached the imaging range 26. The flaw 12 is at a stage where the penetrant 21 has started to come out of the flaw opening 13 onto the surface 11 and has started to form an indication pattern. Next, the flaw 12' shown in FIG. 6(Y) will be described, which has reached the imaging range 26'. The flaw 12' has more penetrant 21 coming out of the flaw opening 13 onto the surface 11 than the flaw 12, forming an indication pattern. The indication pattern formed by the flaw 12' is wider than that formed by the flaw 12. This is called the growth of the indication pattern in this disclosure, and since the presence of the flaw can be observed by observing the growth of the indication pattern, a configuration in which the first automatic imaging device 24, the second automatic imaging device 25, or the third automatic imaging device is provided is preferable. This configuration is preferable because it reduces the time required to complete the observation process compared to when the observation process is performed after the indication pattern has grown sufficiently.

[0049] Next, with further reference to Fig. 6(X)(Y), it will be explained how the injection of superheated steam onto the surface 11 by the steam injection device 20 in the cleaning means accelerates the growth of the indication pattern. The flaw 12 in Fig. 6(X) is in a state where a small amount of the penetrant 21 has oozed onto the surface 11 to form an indication pattern, but at this time, the temperature inside the defect 14 and the surface vicinity 16 has risen due to heating by the superheated steam. As a result, the air pressure inside the defect 14 has risen, and a pressure difference has occurred between the inside of the defect 14 and the atmospheric pressure, so that this pressure generates a force pushing the penetrant 21 onto the surface 11. This force increases the speed at which the penetrant 21 oozes onto the surface 11. In addition, the viscosity of the penetrant 21 has been reduced by heating with the superheated steam, and the surface 11 has dried quickly, which also contributes to the increase in the speed at which the penetrant 21 oozes onto the surface 11. This accelerates the growth of the indication pattern.

[0050] Distinguishing between indications and pseudo indications cannot be generalized because there are various patterns depending on the condition of surface 11, but as the growth of the indications accelerates, the change in the indications becomes more noticeable, and by capturing this with an observation means it may be possible to determine the presence or absence of scratches, so it is preferable to make the growth of the indications observable between 1 and 20 seconds after the end of cleaning step 32. However, from the standpoint of saving time, it is fully possible and preferable to do this between 1 and 10 seconds from the completion of cleaning step 32.

[0051] Next, the penetrant inspection method of the present invention and the steps and areas in which the penetrant inspection device 1 performs the method will be described in detail. FIG. 7 is a schematic diagram showing the progress of the test object through the carry-in / carry-out process area 136 in which the carry-in process is performed, the heating process area 140 in which the heating process 40 is performed, the penetrant process area 131 in which the penetrant process 31 is performed, the cleaning process area 132 in which the cleaning process 32 is performed, and the carry-in / carry-out process area 136 in which the carry-out process is performed, in the penetrant inspection method of the present invention. FIG. 7 shows that the test object moves on the same line by rotating conveyance, but the present invention is not limited to rotating conveyance, and it is sufficient that a plurality of test objects move on the same line while being processed in each of the above steps. For example, while one of the test objects is undergoing the heating process 40 in the heating process area 140, another test object is undergoing the penetrant process 31 in the penetrant process area 131, and in the cleaning process area 132, another test object is undergoing the cleaning process 32, and these test objects are present on the same line by the same conveyance means.

[0052] FIG. 8 is a schematic diagram showing the rotational transport in FIG. 7 from a perspective view. FIG. 8 shows the penetrant flaw detection device 1 of the present invention, but the central support pillar for power supply and the like are omitted for the sake of explanation, and the diagram is merely a schematic diagram. FIG. 8 shows a handling device 110, a rail for transporting the handling device, a platform for carrying out each area, and a carry-in / out process area 136, a heating process area 140, a penetrating process area 131, and a cleaning process area 132 provided on the platform, which are separated by a partition section 114. The partition section 114 may be composed of a shutter. By using the partition section 114 as a shutter that can be opened and closed, it is possible to prevent, for example, superheated steam sprayed when carrying out the cleaning process 32 in the cleaning process area 132 from affecting other areas.

[0053] The penetrant flaw detection device 1 equipped with the rotary conveying device will be described in more detail with reference to FIG. 8. The rotary conveying device is equipped with a handling device 110, a rail for conveying the handling device, a power supply device (not shown), and a wireless LAN communication system for communicating signals via wireless LAN. As a method of rotary conveying, as shown in FIG. 8, the inspection object is fixed by the handling device 110 in the carry-in / carry-out process area 136, and then the handling device 110 conveys the inspection object to the heating process area 140, then to the permeation process area 131, and then to the cleaning process area 132, and each process is performed in each process area. At that time, while the carry-in process is being performed in the carry-in / carry-out process area 136, another inspection object may be subjected to the permeation process 31 in the permeation process area 131, and the cleaning process 32 may be performed on another inspection object in the cleaning process area 132. For this reason, the number of handling devices 110 provided may be the same as the number of areas in which the processes of the penetrant flaw detection device 1 are carried out, but this is not limited to this, and there may be one or more handling devices 110.

[0054] Next, another embodiment of the penetrant flaw detection device 1 of the present invention will be described in detail with reference to FIG. 9. FIG. 9 shows a case where the number of areas is eight, whereas the number of areas is four in the case shown in FIG. 7. The carry-in process is carried out in the carry-in / carry-in process area 136, then the test object is transported to the pre-treatment area 137, where the pre-treatment process is carried out, then the heating process area 140, where the heating process 40 is carried out, then the test object is transported to the permeation process area where the permeation process 31 is carried out, then the cooling process area 141, where the cooling process 41 is carried out, then the cleaning process area 132, where the cleaning process 32 is carried out, then the drying process area 135, where the drying process is carried out, and then the observation process area 134, where the observation process 34 is carried out. Then the test object is transported to the carry-in / carry-in process area 136, where the carry-out process is carried out, in which the test object is carried out. In these steps, a plurality of objects to be inspected may be processed simultaneously, for example, while one of the objects to be inspected is undergoing pretreatment in the pretreatment step area 137, another object to be inspected is undergoing the heating step 40 in the heating step area 140. In the case of Fig. 9, like the case of Fig. 7 where the penetrant flaw inspection device 1 is configured as in Fig. 8, each area shown in Fig. 9 may be provided on a table-like stand, the objects to be inspected may be transported to each area by the handling device 40, and the partition section 114 may be provided with an openable and closable shutter, and the penetrant flaw inspection device 1 may be configured in the same manner as in the case of Fig. 8.

[0055] Next, the handling device 110 of the penetrant flaw detection device 1 will be described in detail with reference to FIG. 10. The handling device 110 includes a cylinder section 111, a connection section 112, and a clamp section 113. The cylinder section 111 is configured to be able to raise and lower the test object 10 fixed to the handling device 110 by transitioning the connection section 112 and the clamp section 113 from the state of FIG. 10(X) to the state of FIG. 10(Y), or conversely, transitioning from the state of FIG. 10(Y) to the state of FIG. 10(X). For this reason, the cylinder section 111 can use a known technology such as an air cylinder or an electric cylinder. The clamp section 113 is configured to be swingable so that the test object 10 can be clamped and fixed.

[0056] Next, the handling device 110 will be described in more detail with reference to Figures 11 and 12. Figure 11(X) is a front view of the handling device 110, and Figure 12(X) is a top view of the handling device 110. In Figure 12(Y), the clamping part 113 of the handling device 110 is rotated by about 45 degrees, and Figure 11(Y) shows this from the front, while Figures 11(Z) and 12(Z) show the opposite side rotated by 45 degrees. In this way, the connecting part 112 and the clamping part 113 are configured to be rotatable. This allows the inspection object 10 fixed to the handling device 110 to also rotate.

[0057] By rotating or raising and lowering the specimen 10 by the handling device 110, each process or any process that is added arbitrarily can be performed. For example, when a method using steam or dry steam is used in the heating process 40, by rotating the specimen 10, steam or the like can be sprayed evenly on the surface of the specimen 10, and the surface of the specimen 10 can be heated approximately uniformly. In addition, by being able to raise and lower the clamping part 113 of the handling device 110, when the permeation process 31 is performed by immersing the specimen 10 in an immersion tank, the specimen 10 can be immersed by lowering the clamping part 113 and the specimen 10 fixed to the clamping part 113 into the immersion tank for immersion.

[0058] Next, the pretreatment process and drying process will be described in detail as optional additional processes. The pretreatment process is performed when the test object brought in has not been pretreated, and is a process of removing adhesions such as oil stains and cleaning the surface of the test object. The drying process is a process of drying the test object because the indication pattern cannot be formed if the test object is wet. If steam is used in the cleaning process, this process may not be necessary. In the drying process, the surface 11 of the test object 10 is dried by a method of drying with hot air, a method of drying by blowing normal air, or a method of using hot air and air blowing in combination. Air blowing is the cheapest method. If the flow rate of hot air is slow, it takes a long time to dry, so by making the flow rate of hot air as fast as possible, it is possible to dry in a short time. The method of using hot air and air blowing in combination is the most effective and more preferable.

[0059] The penetrant flaw detection device 1 of the present invention is provided with a cleaning means and an observation means in addition to the heating means, and may also be provided with a developing means for carrying out the developing step 33. The developing means is preferably a spraying or coating device for applying a developer or developing solution to the surface 11 of the inspected object 10, and the observation means is preferably composed of a recording medium, a display medium, etc. in addition to the first to third automatic imaging devices, and for each of them, a publicly known device may be used as appropriate.

[0060] Next, the heating means in the penetrant inspection method and penetrant inspection device 1 of this embodiment will be described in more detail. As the heating means, a high-frequency induction heating method, a steam or dry steam method, a hot air method, and an infrared heating method can be used. When using hot air, it is preferable to use dry air, and known means can be used as devices for implementing these heating means. Moreover, the heating means is configured to be able to implement the heating step 40.

[0061] As an example of an embodiment of the penetrant inspection device and penetrant inspection method of the present invention, the action when high-frequency induction heating is used as the heating means will be described in detail below. In the heating step 40 performed in the state of FIG. 4(W), the range from the surface 11 to the penetration depth δ shown in the figure is the surface vicinity 16. The penetration depth δ in this case is an arbitrary value set in advance when an arbitrary penetration depth δ is set in advance in the design in the heating step 40. In the heating step 40, when high-frequency induction heating is performed on the inspection object 10 using, for example, a coil capable of passing an electric current as the heating means, the surface vicinity 16 is heated first. Next, the air on the surface 11 adjacent to the surface vicinity 16 and the air inside the defect 14 are heated. By heating the air, the air remaining inside the defect 14 is heated when the state of FIG. 4(X) is reached in the penetration step 31 shown in FIG. 3. During the penetration time, this heated air is cooled and contracted by the cooling effect of the cooling from the part inside the surface vicinity 16 of the inspection object 10, the cooling by the penetrant 21, and the cooling by the cooling step 41. In particular, when electromagnetic induction heating is used as the heating means, only the surface vicinity 16 is heated. Therefore, it is preferable to perform the heating step 40 by electromagnetic induction heating, since the cooling effect from the inside is large. When the air inside the defect 14 contracts, a force acts to draw the penetrant liquid 21 into the defect 14, and the penetration time for the penetrant liquid 21 to penetrate into the defect 14 is shortened.

[0062] Next, as another example of the penetrant inspection method and penetrant inspection device of the present invention, the heating step 40 and the heating means as the implementation means thereof are applicable to materials in which eddy currents do not easily flow, and the case where the heating means is steam or, among steam, dry steam will be described in detail. In the case of dry steam, although not shown, as an example of this embodiment, the penetrant inspection device 1 is provided with one or more steam injection units. The steam injection unit is composed of an injection nozzle, a hose, a steam supply source, etc., but as long as it is possible to inject steam onto the surface 11, it may be by any suitable known means. In the heating step 40 as another example of this embodiment, the steam injection unit injects dry steam or steam toward the surface 11. At this time, it is preferable that the steam or dry steam has a steam pressure of 0.03 megapascals or more. As a result, the air on the surface 11 becomes heated steam. And the steam penetrates into the inside 14 of the defect. In addition, by heating not only the surface 11 but also the surface vicinity 16 as a target, the air inside the defect 14 is prevented from cooling immediately. By heating in this manner, the air remaining inside the defect 14 is heated when the state of Fig. 4(X) is reached in the permeation step 31 shown in Fig. 3. After the permeation step 31, this heated air is cooled during the permeation time by the cooling effect of the cooling from the portion inside the surface vicinity portion 16 of the object to be inspected 10, the cooling by the permeation liquid 21, and the cooling step 41, and the steam is condensed. As the steam inside the defect 14 condenses, a pressure difference occurs between the defect 14 and the atmospheric pressure, and the permeation liquid 21 is drawn into the defect 14. In this way, the permeation time required for the permeation of the permeation liquid 21 into the defect 14 is shortened.

[0063] Next, the relationship between performing the heating step 40 and the faster penetration time will be described. When the surface 11 is heated to 50 degrees Celsius in absolute temperature by the heating means in the heating step 40, theoretically, when air at 25 degrees is raised by 50 degrees in the heating step 40, the volume expands and increases by 17 percent. In this state, the penetration step 31 is performed and the penetrant 21 is applied to the surface 11. Then, in addition to the force of the penetrant 21 itself trying to enter the defect interior 14, the volume of the air in the defect interior 14, which expanded by 17 percent, returns to its original state as the temperature approaches room temperature, and the volume decreases by about 17 percent. This makes it possible to instantly draw a large amount of the penetrant 21 into the defect interior 14. In relation to performing the heating step 40 and the cooling step 41, if the cooling step 41 is performed by pouring room temperature water or immersing the test object within 30 seconds, more preferably within 10 seconds, after the completion of the penetrating step 31, an overshoot occurs as a result of rapid cooling, and more penetrant liquid enters the defect interior 14, which is more preferable.

[0064] As an example of an embodiment of the penetrant inspection device and penetrant inspection method according to the present invention, the case where the heating means is only hot air or only infrared heating will be described. When only these means are used, the heating time, which is the time required to heat the surface 11 to an absolute temperature of 30 degrees Celsius or more, may take about one minute or more. Therefore, even if the surface vicinity 16 is heated, thermal diffusion occurs, and the inner part of the object 10, which is closer to the surface vicinity 16, also becomes hot. In this case, the cooling effect on the surface vicinity 16 due to the inner part of the object 10 being at room temperature is weakened. Therefore, it is particularly preferable to provide a cooling process 41.

[0065] Next, as an example of an embodiment of the penetrant inspection device and penetrant inspection method according to the present invention, the case where the heating means is only steam or only high-frequency induction heating will be described. When the heating means is only hot air or only infrared heating, it is difficult to heat the surface 11 to 30 degrees Celsius or more in absolute temperature within 10 seconds, whereas when the heating means is only steam or only high-frequency induction heating, it is fully possible to heat the surface 11 to 30 degrees Celsius or more in absolute temperature even if the heating time is within 10 seconds. Therefore, when the heating means is only steam or only high-frequency induction heating, the heating time can be kept within 10 seconds, and as a result, thermal diffusion is sufficiently suppressed. Therefore, when the heating means is only steam or only high-frequency induction heating, it is preferable to provide the cooling process 41, but the cooling process 41 may not be provided.

[0066] Next, the point that each step of the steps shown in FIG. 8 and other optional steps is completed within 2 minutes will be described in detail. It is preferable that each step shown in FIG. 8 and the like is completed within 2 minutes. More preferably, it is even more preferable that each step is completed within 1 minute. Conventionally, the time required for penetration and development was long, which was a bottleneck. However, in the present invention, by adopting a heating device for performing the heating step, the penetration time is shortened, and the cleaning device is provided that can inject superheated steam with a temperature of 110 degrees or more immediately after injection from the nozzle of the steam injection device, so that this bottleneck can be eliminated. When the steps are performed on the same line, or especially when using a rotary conveyance such as a merry-go-round type, each step is performed simultaneously in the area where each step shown in the penetrant inspection device as shown in FIG. 7 and FIG. 9 is performed, if a step that takes a long time even for only one step is designed, it is necessary to design it so that the time is increased in all steps or the number of steps is increased by adding an optional step. However, by configuring the heating and cleaning processes to eliminate the bottlenecks as described above, the present invention makes it possible to complete each process within two minutes, and more preferably within one minute, thereby providing a penetrant inspection device and a penetrant inspection method that can shorten the time for the penetrant testing itself.

[0067] Next, a method for supplying power to the penetrant flaw detector 1 of this embodiment and a method for communicating a control signal will be described in detail. The penetrant inspection device 1 of this embodiment uses a rotary conveyance, and a handling device 110 is used to fix the object 10 to be inspected in the rotating device. The handling device 110 has a function to raise and lower the object 10 to be inspected and a function to rotate it, but it is necessary to supply a power source and a signal for electrically controlling it. For this purpose, a rotary connector (slip ring) using a metal such as copper or silver for the contact point or a rotary connector (rotary connector) using a liquid metal has been used in the past. However, since the slip ring forms a sliding contact point with a ring-shaped electrode part and a brush-shaped electrode part, it is necessary to periodically clean the wear powder, and the slip ring must be replaced when it reaches the end of its life. In addition, in the case of a slip ring, if the number of poles of the power or signal line increases, the slip ring itself becomes large, and it becomes impossible to make a compact penetrant inspection device. In addition, noise may be generated due to sliding.

[0068] Furthermore, when using rotary connectors, liquid metal is used for the contacts, and mercury-based connectors have traditionally been widely used because they have a low melting point and are inexpensive. Mercury-based connectors have the advantage of low contact resistance, low noise, and can be made smaller. However, they are costly to dispose of and have the risk of leaking from the contacts. In particular, if leakage does occur, there is a high risk of contamination of the production line and health damage. In the penetrant flaw detection device 1 of this embodiment, it is preferable to use a wireless power supply system. Since the wireless power supply system is an electromagnetic induction type, it is safe because it does not produce wear powder, has a long life, and does not pollute the environment. Since the wireless power supply system has a drawback that the efficiency drops significantly when the distance between the two coils increases, it is preferable to install the wireless power supply system on the shaft of the rotating device in the penetrant flaw detection device of this embodiment. The control signal can be exchanged from the control device via wireless LAN, thereby reducing the maintenance work. Therefore, it is preferable that the penetrant flaw detection device 1 of this embodiment is equipped with at least a wireless LAN communication system. In order to stabilize the control signal, it is preferable to install the wireless LAN master unit and the wireless LAN communication system (slave unit) as close to each other as possible from the viewpoint of noise countermeasures.

[0069] Next, the penetrant inspection device 1 of the present invention will be further described. The penetrant inspection device 1 of the present invention may include a heating means for performing the heating step 40, a penetrating means for performing the penetrating step 31, a cooling means for performing the cooling step 41, a cleaning means for performing the cleaning step 32, a developing means for performing the developing step 33, and an observation means for performing the observation step 34. As the penetrating means, a known means such as a means for applying the penetrating liquid 21 to the object to be inspected 10 by a spraying device may be used, as the cooling means, a known device for blowing cold air, as the developing means, a device for applying the developing liquid to the object to be inspected 10, and the like, each of which may be a known device. In addition, the penetrant inspection device 1 of the present invention may be appropriately designed so as to be able to carry out the penetrant inspection method of the present invention.

[0070] The present disclosure can be suitably used for the purpose of inspecting defects in industrial parts and the like made of a non-magnetic material as the inspection subject 10. However, the present disclosure is not limited to this, and can be widely used in the inspection of products that require flaw detection. [Explanation of symbols]

[0071] 1, Penetrant testing equipment 10. Test object 11, surface 12,12´, Kizu 13. Defective opening 14. Defect inside 16. Near surface 20. Steam injection device 21, Penetration liquid 22, Suction recovery section 23. Ventilator 24, the first automatic imaging device 25, second automatic imaging device 26, 26´ Imaging range 31, Penetration process 32,32´, Cleaning process 33, Development process 34, 34´, Observation process 40,Heating process 41, Cooling process δ Penetration depth 110 Handling Equipment 111 Cylinder section 112 Connection 113 Clamp section 114 Partition 131, Penetration process area 132. Cleaning process area 134, Observation process area 135 Drying Process Area 136 Loading / unloading area 137 Pre-treatment area 140, Heating process area 141, Cooling process area

Claims

1. A penetrant flaw detection apparatus including a device for performing a penetrant step of applying a penetrant liquid to a surface of an object to be inspected, a cleaning device for performing a cleaning step of removing the penetrant liquid from the surface of the object to be inspected, and a device for performing an observation step of observing an indication pattern, The penetrant flaw detection apparatus further includes a heating device for performing a heating step prior to the penetrating step, The heating device is capable of heating the surface of the test object by 30 degrees or more in absolute temperature, The cleaning device is configured to be capable of injecting superheated steam onto a surface of the object to be inspected from an injection port of a nozzle of the steam injection device, The penetrant inspection apparatus further includes a transport device, The penetrant inspection apparatus further includes one or more handling devices for fixing the test object, The penetrant flaw detection device is characterized in that the conveying device forms a line, and loading and unloading can be performed in the same area on the line.

2. 2. The penetrant inspection apparatus according to claim 1, wherein the conveying device is a merry-go-round type rotary conveying device.

3. The penetrant flaw detection device according to claim 2 or 3, further comprising a wireless power supply system and a wireless LAN communication system.

4. A penetrant inspection method including a penetrant step of applying a penetrant to an object to be inspected, a cleaning step of removing the penetrant from a surface of the object to be inspected, and an observation step of observing an indication pattern, The penetrant inspection method further includes a heating step prior to the penetrating step, The penetrant inspection method includes the heating step, the penetrating step, the cleaning step, and the observation step, and further includes a cooling step immediately after the penetrating step to allow the penetrant to penetrate, a drying step to dry the water wetted in the cleaning step, a carrying-out step, and a carrying-in step, and any other optional steps. The heating step, the penetrating step, the cleaning step, the observation step, and the optional cooling step, the drying step, the carrying-out and carrying-in steps, and other steps, which are included in the penetrant inspection method, are all completed within 2 minutes; The heating step is a step of heating a surface of the test object to 30 degrees or more in absolute temperature, The penetrant inspection method, characterized in that the cleaning step is a step of cleaning the surface of the test object by injecting steam from a steam injection device, and the steam injected by the steam injection device is superheated steam.

5. The penetrant inspection method according to claim 4, further comprising a cooling step performed after the penetrating step is completed and before the cleaning step is started, and the cooling step is started within 30 seconds after the penetrating step is completed.

Images