Liquid penetrant inspection method and liquid penetrant inspection apparatus

Abstract

To provide a penetrant inspection device and a penetrant inspection method capable of suppressing the consumption of an excess penetrant and easily managing the consumption of the penetrant.SOLUTION: The liquid penetrant inspection method sequentially includes a heating process 40, a penetration process 31, a cooling process 41, a cleaning process 32, a developing process 33, and an observation process 34, and further includes a mounting process and a moving process that can be performed in the penetration process 31, the cleaning process 32, and the like. The object 10 is held in the hole 47 of the holder 45. The placing step is a step in which the holder 45 is positioned at a predetermined height with reference to the base 49 and the inspection object 10 is placed on the base 49 to form the gap 48, and the moving step is a step in which, for example, the first moving step 60, the second moving step 61, the third moving step 62, and the second moving step 61 are sequentially performed, and the penetrant testing method repeats the moving step a plurality of times.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a penetrant inspection method and apparatus, and more particularly to a method and apparatus for penetrating a penetrant into a flaw on the surface of an object to be inspected. [Background technology]

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

[0003] Conventional penetrant testing methods include a penetrant application process, in which a penetrant is applied to the surface of an object to be inspected and the penetrant penetrates open defects present on the surface of the object. This process is followed by a cleaning process, in which excess penetrant remaining on the surface of the object without penetrating into the defects is removed using a cleaning solution, leaving only the penetrant remaining within the defects. After the cleaning solution dries, a uniform thin layer of developer is formed on the surface of the object to absorb the penetrant that has penetrated into the defects, revealing a defect indication pattern on the surface of the layer. This is followed by an observation process, in which the defect indication pattern is confirmed under visible or ultraviolet light. If the surface of the object to be inspected contains oil or other contaminants, a pre-cleaning process is performed to clean the surface using an organic solvent or the like. The penetrant is typically a non-volatile, highly penetrating liquid prepared by dissolving a red dye or fluorescent dye in a petroleum-based mixed solvent or an aromatic solvent, with the addition of a plasticizer, surfactant, or the like. Another known cleaning process involves using an organic solvent capable of dissolving the penetrant or water to wash away the excess penetrant.

[0004] Patent Document 1 discloses an automatic dye penetrant inspection system that applies a dye penetrant to the surface of a test object, then washes the dye penetrant off the surface, dries, and develops it to determine whether the test object has defects. The system features a dye penetrant tank, a cleaning device, and a drying device arranged on a semicircular arc, with a vertically movable and rotatable lifting ball at the center of the arc. The ball has an arm with a hook at the end, which lifts a basket containing the test object by moving the ball vertically and rotating it, and then rotates it to the position of the dye penetrant tank, cleaning device, and drying device, and then suspends it within these devices. While the technology disclosed in Patent Document 1 allows the test object to be transported between processes, the test object is transported in a basket. As a result, the penetrant tends to adhere to the basket, and excess penetrant inevitably remains on the test object.

[0005] [Patent Document 1] Japanese Patent Application Publication No. 58-223046 Summary of the Invention [Problem to be solved by the invention]

[0006] As described above, conventional penetrant testing devices have the drawback of consuming a large amount of penetrant liquid and producing a large amount of waste liquid during the cleaning process because the test object is transported in a basket. Furthermore, in the conventional penetrant testing process, a long penetrant time is required to fully penetrate the open defects present on the surface of the test object. The long penetration time required during the penetrant testing process creates a bottleneck, reducing line efficiency and requiring a large amount of space. Therefore, conventional penetrant testing methods are virtually ineffective for parts with high production volumes or parts that must be inspected in real time. The present invention provides a penetrant testing method and a penetrant testing device used therefor that solve these problems. [Means for solving the problem]

[0007] Therefore, the penetrant flaw detection device of the present invention is capable of performing a penetrant process of applying a penetrant liquid to the surface of a spherical object to be inspected, or a cleaning process of removing the penetrant liquid, and is characterized in that the penetrant flaw detection device further comprises a holder having a circular hole for holding the object to be inspected, and a flat base on which the object to be inspected can be placed, the holder being configured to be able to hold the object at a predetermined height relative to the base, the predetermined height being a height at which the object to be inspected held by the holder comes into contact with the base and the circular hole of the holder has a gap between it and the object to be inspected, and the holder being configured to be able to move approximately horizontally and relatively to the base when the holder is positioned at the predetermined height relative to the base.

[0008] In addition, the penetrant flaw detection device of the present invention is characterized in that the diameters of the test objects held by the holder at the same time are the same, and when the holder holds test objects with different diameters, the specified height can be adjusted according to the diameters of the test objects.

[0009] In addition, the penetrant flaw detection device of the present invention is characterized in that the base is flexible enough to allow a recess to be formed by the weight of the test object and is formed from a flexible material that can be impregnated with the penetrant liquid.

[0010] Furthermore, the penetrant flaw detection method of the present invention is a penetrant flaw detection method using the penetrant flaw detection device described in claim 1, characterized in that the penetrant flaw detection method includes at least the penetrating step, and in the penetrating step, the penetrant liquid is dropped onto the center of each test object.

[0011] Furthermore, the penetrant flaw detection method of the present invention is a penetrant flaw detection method using the penetrant flaw detection apparatus of claim 1, the penetrant flaw detection method comprising a moving step, the moving step comprising a first moving step, a second moving step, and a third moving step, the first moving step, the second moving step, and the third moving step all being steps in which the holder is held at the predetermined height and moved approximately horizontally and relatively with the base as a reference, the first moving step being a step of linearly moving the holder in a fixed direction a distance equal to or greater than the circumferential distance of the object to be inspected, the second moving step being a step of linearly moving the holder in a direction perpendicular to the fixed direction on a horizontal plane, the third moving step being a step of linearly moving the holder in a direction opposite to the fixed direction on a horizontal plane a distance equal to or greater than the circumferential distance of the object to be inspected, the moving steps being steps in which the first moving step is followed by the second moving step, the third moving step, and the second moving step are performed in sequence, and the moving steps are repeated two or more times.

[0012] Furthermore, the penetrant flaw detection method of the present invention is a penetrant flaw detection method using the penetrant flaw detection device described in claim 1, and the penetrant flaw detection method includes a transporting step of transporting the test object from a penetrant flaw detection area for carrying out the penetrant flaw detection process to a cleaning flaw detection area for carrying out the cleaning flaw detection process after the penetrant flaw detection process, and the transporting step includes lifting the holder, which is positioned at the predetermined height relative to the base, from the predetermined height position, so that the test object can be fitted into the holder and transported, and the penetrant flaw detection method further includes a heating step of increasing the surface temperature of the test object, and the cleaning step involves cleaning the surface of the test object with steam. [Effects of the Invention]

[0013] In a penetrant inspection device capable of performing a penetrant process of applying a penetrant liquid to the surface of a spherical object to be inspected, or a cleaning process of removing the penetrant liquid, the penetrant inspection device further comprises a holder having a circular hole for holding the object to be inspected, and a flat base on which the object to be inspected can be placed, the holder being configured to be able to hold the object at a predetermined height relative to the base, the predetermined height being a height at which the object to be inspected held by the holder comes into contact with the base when the holder is positioned at the predetermined height relative to the base, and there is a gap between the circular hole in the holder and the object to be inspected, and the holder being configured to be able to move approximately horizontally and relatively with respect to the base when the holder is positioned at the predetermined height relative to the base.This makes it possible to rotate the object to be inspected, allowing the penetrant liquid to be applied evenly and thinly, and by performing the cleaning process while rotating the object to be inspected, a penetrant inspection method can be provided in which excess penetrant liquid on the object to be inspected can be cleanly removed.

[0014] The penetrant flaw detection device of the present invention is characterized in that the diameters of the test objects held by the holder at the same time are the same, and when the holder holds test objects of different diameters, the height can be adjusted to a predetermined value according to the diameter of the test object.Therefore, even if test objects of different diameters are to be held at different times, the test object can be rotated, and the penetrant liquid can be applied evenly and thinly.Furthermore, by performing a cleaning process while rotating the test object, it is possible to provide a penetrant flaw detection device that can cleanly remove excess penetrant liquid from the test object.

[0015] The penetrant flaw detection device of the present invention is characterized in that the base is formed from a flexible material that is flexible enough to form a recess due to the weight of the object being inspected and can be impregnated with penetrant liquid.This allows for a large contact area, makes it difficult for the object being inspected to slip, allows the penetrant liquid to be applied evenly, and prevents the application of excess penetrant liquid, making it possible to provide a penetrant flaw detection device.

[0016] The penetrant flaw detection method of the present invention is a penetrant flaw detection method using the penetrant flaw detection device described in claim 1, and is characterized in that it includes at least a penetrating step, in which the penetrant liquid is dripped onto the center of each test object.Therefore, when dripping using a touch valve, it is possible to provide a penetrant flaw detection method that can reliably drip the liquid onto a spherical test object.

[0017] The penetrant flaw detection method of the present invention is a penetrant flaw detection method using the penetrant flaw detection device according to claim 1, and the penetrant flaw detection method includes a moving step, which includes a first moving step, a second moving step, and a third moving step, and the first moving step, the second moving step, and the third moving step are all steps in which a holder is held at a predetermined height and moved approximately horizontally and relatively with respect to a base, and the first moving step is a step in which the holder is moved linearly in a fixed direction over a distance equal to or greater than the circumferential distance of the object to be inspected, and the second moving step is a step in which the holder is moved perpendicular to the fixed direction on a horizontal plane. The first moving step is a step of linearly moving the holder in a direction opposite to the fixed direction on a horizontal plane by a distance equal to or greater than the circumferential distance of the object to be inspected, and the second moving step, the third moving step is a step of linearly moving the holder in a direction opposite to the fixed direction on a horizontal plane by a distance equal to or greater than the circumferential distance of the object to be inspected, and the moving steps are performed in the order of the first moving step, the second moving step, the third moving step, and the second moving step, and are characterized in that the moving steps are repeated two or more times, so that in the penetrating step, the penetrating liquid can be evenly applied to the surface of the spherical object to be inspected, and a penetrant inspection method that is also effective in the cleaning step, heating step, and drying step can be provided.

[0018] The penetrant flaw detection method of the present invention is a penetrant flaw detection method using the penetrant flaw detection device described in claim 1, and the penetrant flaw detection method includes a transporting step of transporting the test object from a penetrant flaw detection area for carrying out the penetrant flaw detection process to a cleaning flaw detection area for carrying out the cleaning flaw detection process after the penetrant flaw detection process, and in the transporting step, a holder positioned at a predetermined height relative to the base is lifted from the predetermined height position, so that the test object can be fitted into the holder and transported, and the penetrant flaw detection method further includes a heating step of raising the surface temperature of the test object, and in the cleaning step, the surface of the test object is cleaned with steam.Therefore, it is possible to provide a penetrant flaw detection method in which the transporting step can be carried out efficiently, the penetrant flaw detection time can be shortened by the heating step, and the drying time can be shortened by cleaning with steam and the amount of wastewater can be reduced. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 2 is a flowchart of a penetrant flaw detection method according to the present embodiment. [Figure 2] 10 is a schematic cross-sectional view showing the transition of the state around the flaw 12 in the penetrant inspection method according to this embodiment, where (W) is the state before the penetrant process 31 is performed, (X) is the state immediately after the penetrant liquid 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 of (X) during the penetrant process 31, and (Z) is a conceptual diagram showing the state around the flaw 12 after the cleaning process 32. [Figure 3] 4 is a plan view showing a holder 45 and a hanger 46 which are parts of the penetrant flaw detection device according to the present embodiment. FIG. [Figure 4] 4 is a plan view showing the state in which the object under test 10 is held by the holder 45 shown in FIG. 3. FIG. [Figure 5] FIG. 5 is a cross-sectional view taken along the line W-W in FIG. 4. [Figure 6] FIG. 2 is a perspective view showing an inspection object 10 held by a holder 45 which is a part of the penetrant flaw detection device according to the present embodiment. [Figure 7]This is a diagram showing the state in which the touch valve 70 provided in the penetrant flaw detection device of this embodiment drips the penetrant liquid 21, (X) is an explanatory diagram showing the state before dripping, and (Y) is an explanatory diagram showing the state at the time of dripping. [Figure 8] This figure shows the test object 10 held by the holder 45 when the penetrant liquid 21 is dripped in the penetrant flaw detection device of this embodiment, (X) is a figure showing the test object 10 after the penetrant liquid 21 is dripped, before the holder 45 is moved and before the test object 10 is rotated in the α direction, and (Y) is an explanatory figure showing the test object 10 after the holder 45 has moved horizontally from the state of (X) and the test object 10 has rotated in the α direction. [Figure 9] 1 is a partially enlarged cross-sectional view showing a part of the holder 45 and the object to be inspected 10 in a horizontal cross section including a hole 47 and a corner 50. FIG. [Figure 10] (X) is a cross-sectional view of the object to be inspected 10 held by the holder 45, and (Y) is a cross-sectional view of the object to be inspected 10', which has a smaller diameter than the object to be inspected 10 in (X), held by the same holder 45 as in (X). [Figure 11] 10 is a cross-sectional view showing a holder 45, a hanger 46, and a second holder 51, which is another example of the penetrant flaw detection device according to the present embodiment. FIG. [Figure 12] This is an explanatory cross-sectional view showing the time when steam 82 is sprayed onto the object 10 to be inspected by the cleaning nozzle 81 provided in the penetrant flaw detection device of this embodiment in the cleaning process 32 provided in the penetrant flaw detection method of this embodiment. [Figure 13] (X) is a diagram showing the direction of movement when the holder 45 moves relative to the base as a reference, as an example of the penetrant testing method of this embodiment, and (Y) is a diagram showing the direction of movement when the holder 45 moves relative to the base as a reference, as another example of the penetrant testing method of this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0020] The details of the embodiments of the present invention will be described below with reference to the drawings. First, the penetrant inspection method according to this embodiment will be described. FIG. 1 is a flowchart of the penetrant inspection method as an example of an embodiment according to the present invention. FIG. 2 is a schematic cross-sectional view showing the transition of the state around the flaw 12 in the penetrant inspection method according to this embodiment, 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 applying the penetrant to the flaw 12 during the penetrant step 31. (Y) represents the state around the flaw 12 after a shorter penetration time has elapsed since the state (X) during the penetrant step 31. (Z) represents the state around the flaw 12 after the cleaning step 32. FIG. 3 is a plan view showing a holder 45 and a hanger 46, which are parts of the penetrant inspection apparatus according to this embodiment. Components other than the holder 45 and the hanger 46 are not shown. FIG. 4 is a plan view showing the inspection object 10 held by the holder 45 shown in FIG. 3. FIG. 5 is a cross-sectional view taken along line W-W in FIG. 4 , showing the object under test 10 held by a holder 45, which is part of the penetrant flaw detection apparatus according to this embodiment, and placed on a base 49. FIG. 6 is a perspective view showing the object under test 10 held by a holder 45, which is part of the penetrant flaw detection apparatus according to this embodiment. A hanger 46 and other components are not shown. FIG. 7 is a diagram showing the touch valve 70 of the penetrant flaw detection apparatus according to this embodiment dripping the penetrant 21, where (X) shows the state before dripping and (Y) shows the state during dripping. FIG. 8 is a diagram showing the object under test 10 held by the holder 45 when the penetrant 21 is dripped in the penetrant flaw detection apparatus according to this embodiment. (X) shows the state before the holder 45 is moved after the penetrant 21 has dripped and before the object under test 10 is rotated in the α direction. (Y) is an explanatory diagram showing the state after the holder 45 has moved linearly horizontally from the state shown in (X) and the object under test 10 has rotated in the α direction. Fig. 9 is a cross-sectional view showing the holder 45 and the object under test 10 in a horizontal cross section with the hole 47 and the corner 50. Fig. 10(X) is a cross-sectional view showing the object under test 10 held by the holder 45, and Fig. 10(Y) is a cross-sectional view showing the object under test 10' having a smaller diameter than the object under test 10 in (X) being held by the same holder 45 as in (X).Fig. 11 is a cross-sectional view showing holder 45, hanger 46, and second holder 51, which is another example of the penetrant flaw detection apparatus according to the present embodiment. Fig. 12 is an explanatory cross-sectional view showing a state in which steam 82 is sprayed onto inspection object 10 from cleaning nozzle 81 provided in the penetrant flaw detection apparatus according to the present embodiment in cleaning step 32 provided in the penetrant flaw detection method according to the present embodiment. Fig. 13(X) is a diagram showing the movement direction when holder 45 moves relatively with respect to the base as a reference, as an example of the penetrant flaw detection method according to the present embodiment, and Fig. 13(Y) is a diagram showing the movement direction when holder 45 moves relatively with respect to the base as another example of the penetrant flaw detection method according to the present embodiment. In this disclosure, for the sake of convenience, when simply referring to the upper side, it refers to the upper side in Figures 5, 7, 8, 11, 12, and 13, and when simply referring to the lower side, it refers to the lower side in Figures 5, 7, 8, 11, 12, and 13.

[0021] Next, a penetrant inspection method and a penetrant inspection device using this method according to the present invention will be described in detail with reference to FIGS. 1 and 2. The steps shown in FIG. 1 are a flowchart illustrating the steps of a penetrant inspection method according to an embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating the enlarged view of a flaw 12 on an object to be inspected 10, which is the target of detection in the penetrant inspection method, in each of the (W) to (Z) views. Unlike conventional methods, the penetrant inspection method according to this embodiment may include a heating step 40 shown in FIG. 1. In the heating step 40, heating is performed toward the surface 11 by a heating means. The heating means for performing the heating step 40 may include a hot water bath and a steam or hot air spraying unit. After immersing the object to be inspected in hot water stored in the hot water bath, the object to be inspected 10 may be pulled out of the hot water bath and then superheated steam may be sprayed onto the surface 11 by the steam spraying unit, or high-temperature hot air of 100°C or higher may be sprayed onto the surface 11 by the hot air spraying unit. Other known methods may also be used. Drying the surface 11 by the heating means allows the penetrant to penetrate the surface 11 effectively. Furthermore, by heating the surface 11 and the surface vicinity 16 by the heating means, the air inside the defect 14 in the inspection object 10 after the heating step 40 is performed expands, making it easier to draw in the penetrant 21. In the present disclosure, superheated steam refers to steam with a steam temperature of 100°C or higher. Furthermore, the heating step 40 may be performed when it is desired to shorten the cycle time, and may be omitted in the penetrant inspection method of the present invention.

[0022] Next, a penetrant testing method according to an embodiment of the present invention will be described in more detail with reference to FIGS. 1 and 2. The penetrant testing method according to an embodiment of the present invention shown in FIG. 1 is a method that sequentially performs 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. In this manner, the penetrant testing method according to this embodiment first performs the heating step 40. The heating step 40 is performed in the initial state shown in FIG. 2(W). After this state, the surface 11 is heated by a heating means, and then the penetrant testing step 31 is performed. In the heating step 40, it is preferable to heat the surface 11 to a temperature of 20 degrees Celsius or more in absolute terms. This means that the penetrant testing is usually performed at room temperature, and therefore the surface 11 is heated by 20 degrees Celsius or more. By heating in this manner, the penetration time is significantly reduced.

[0023] 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 process 31 until the penetrant liquid 21 has sufficiently penetrated into the interior 14 of the defect for penetrant testing and the object can be moved to the next cleaning process 32.

[0024] In the heating step 40, it is preferable to raise the absolute temperature of the surface 11 by 20 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. In this way, when the absolute temperature of the surface 11 is raised by the heating means by 50 degrees Celsius or more, it is possible to reach a state in which the penetrant 21 has penetrated 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 testing, which is preferable.

[0025] 1, the penetrant step 31 in the penetrant inspection method according to this embodiment is performed by applying the penetrant liquid 21 to the surface 11 of the object to be inspected 10. This results in a transition to the state shown in FIG. 2(X). The penetrant liquid 21 is applied to the object to be inspected 10 using a holder 45 and a base 49 shown in FIGS. 3, 5, etc.

[0026] Here, a method for applying the penetrant liquid 21 to the object 10 using the holder 45 and the base 49 in the permeation step 31 will be described in detail. The permeation step 31 includes a placing step, a dropping step, and a moving step. After the placing step, the dropping step and the moving step may be performed sequentially or simultaneously.

[0027] First, the loading process will be described in detail. FIG. 3 shows a plan view of a holder 45 included in the penetrant flaw detection system according to this embodiment. The holder 45 shown in FIG. 3 is flat, has a circular hole 47, and is suspended from a hanger 46 so as to be approximately horizontal. Although the hole 47 is circular, it is preferable to set its diameter smaller than that of the test object 10, 10', as this facilitates transport of the test object 10 during the transport process. Furthermore, the material of the holder 45 is preferably metal, fluorine-based plastic, silicone, or the like. Fluorine-based plastic and silicone are preferable due to their low coefficient of friction. FIGS. 4, 5, and 6 show the test object 10 held in the holder 45 included in the penetrant flaw detection system according to this embodiment. FIG. 4 shows a plan view of the test object 10 held in the holder 45, and FIG. 5 shows a cross-sectional view taken along line W-W in FIG. 4. 4, 5, and 6, in the placing step, the holder 45 holds the object under test 10 in the hole 47, and at the same time, the object under test 10 is placed on the base 49. In addition, as shown in FIG. 5, a gap 48 is formed between the object under test 10 placed on the base 49 and the hole 47.

[0028] Although not shown, the placement step is a step of moving from a state in which the hanger 46 is fitted into the holder 45 and held apart from the base 49 to a state in which the hanger 46 is moved downward to place the object under test 10 on the base 49, as shown in Figures 4, 5, and 6, so that the object under test 10 is held between the holes 47 and there is a gap 48 between the hole 47 and the object under test 10. Although the gap 48 is formed in a fixed direction in Figures 5 and 6, the placement step is not limited to this, and the gap 48 may be formed around the entire periphery, for example.

[0029] Next, the dropping step will be described in detail. Fig. 7 shows how the penetrant 21 is dropped onto the object to be inspected 10 by the touch valve 70 after the placing step. The touch valve 70 will be described in detail with reference to Fig. 7(X). The touch valve 70 comprises a tube 71, an O-ring 72, a piston 73, and the penetrant 21. The penetrant 21 is held within the tube 71, and a piston 73 is provided in the center of the tube 71, with an O-ring 72 provided at the discharge section between the piston 73 and the tube 71.

[0030] FIG. 7(X) shows a stage before the piston tip 74, which is the tip portion of the piston 73 of the touch valve 70, comes into contact with the object under test 10. FIG. 7(Y) shows a state in which the piston tip 74, which is the tip portion of the piston 73 of the touch valve 70, comes into contact with the object under test 10 toward the center of the object under test 10, and the penetrant liquid 21 is applied to the object under test 10. The touch valve 70 assists in applying the penetrant liquid 21 to the object under test 10 and also serves to replenish the penetrant liquid 21 applied to the base 49 shown in FIG. 8. The touch valve 70 is preferable because it drips the penetrant liquid 21 toward the center of the object under test 10, which more reliably presses the object under test 10 with the piston tip 74 and ensures reliable dripping. Furthermore, the use of the touch valve 70 makes it possible to replenish the penetrant liquid 21 only as it is consumed, which is preferable because the penetrant liquid 21 does not overflow at the base 49.

[0031] Conventionally, the method of applying the penetrant liquid has been to place the object to be inspected 10 in a basket and immerse it in a layer of penetrant liquid, but this has the drawback of causing the penetrant liquid 21 to adhere to the basket, resulting in unnecessary consumption.This disclosure discloses a penetrant flaw detection device and a penetrant flaw detection method that solves this problem.

[0032] Next, the moving step will be described in detail. In the moving step, holder 45 moves horizontally relative to base 49 in the X direction shown in Figures 5 and 8. The moving direction in Figures 5 and 8 is an example for explanation, and the moving direction is not limited to the X direction. As a result, object 10 abuts against corner 50 and rotates in the α direction, and gap 48 is formed on the right side in Figure 5. Note that holder 45 only needs to move relative to base 49, so for example, the position of holder 45 may be fixed and base 49 may move in the Z direction, which is the opposite direction to the X direction.

[0033] The state shown in Fig. 8(Y) is reached by horizontally moving the holder 45 relative to the base 49 in the X direction shown in Fig. 5 and Fig. 8(X), which will be described in detail below. Fig. 8 is a cross-sectional view showing one piece of the test object 10, which is a part of Fig. 5. Fig. 8(X) shows the state after the dropping step. As shown in Fig. 8(X), after the dropping step, excess penetrant liquid 22 adheres to the test object 10. From this state, the holder 45 moves horizontally relative to the base 49 in the X direction.

[0034] Next, referring to FIG. 8(Y), we will explain how excess penetrant 22 drips from the test object 10 as the holder 45 moves horizontally relative to the base 49. FIG. 8(Y) shows the state in which the holder 45 moves in the X direction relative to the base 49 from the state in FIG. 8(X). As the holder 45 moves in the X direction relative to the base 49, the test object 10 rotates in the α direction and moves relative to the base 49. This causes the test object 10 to contact a corner 50 on the edge of the hole 47 of the holder 45. This causes excess penetrant 22 to drip downward. This reduces the consumption of excess penetrant 22 and allows the penetrant step 31 to be performed with the minimum necessary consumption of penetrant 21, which is preferable. Furthermore, if excess penetrant 22 were left on the test object 10, the penetrant layer would thicken, resulting in variations in thickness. In contrast, removing the excess penetrant liquid 22 thins the layer of penetrant liquid on the surface of the inspection object 10, making it easier to keep the thickness of the layer of penetrant liquid constant and stabilizing the amount of penetrant liquid consumed. This has the advantage of facilitating management such as replenishing the penetrant liquid, as the amount of penetrant liquid consumed is stabilized.

[0035] The contact between the object under test 10 and the corner 50 provided on the edge of the hole 47 of the holder 45 is a point contact in the cross section shown in Fig. 8, but in reality, if there is a line contact as shown in Fig. 9, it is more preferable because it prevents slippage, such as the object under test 10 not rotating. However, even though there is a line contact, strictly speaking it is a point contact because the circumferences are different.

[0036] Next, the placement of the holder 45 at a predetermined height relative to the base 49 in the placement step will be described in detail. The placement step is a step in which, as shown in FIGS. 4 and 5 , the hanger 46 is moved downward to place the object under test 10 on the base 49, and the object under test 10 is held between the holes 47, with a gap 48 formed between the holes 47 and the object under test 10. In order to form this gap 48, the holder 45 is appropriately designed to be positioned at a predetermined height at which the gap 48 is formed between the holes 47 and the object under test 10 when the object under test 10 is placed on the base 49. This predetermined height is appropriately designed depending on the sizes of the holes 47 and the object under test 10.

[0037] 9 is a cross-sectional view taken along a horizontal plane where a corner 50, which is the edge of a circular hole 47, is located. The "predetermined height" refers to the distance between the base 49 and the horizontal plane where the corner 50 is located. When the circumference of the hole 47 is taken as 100 percent of the horizontal plane where the corner 50 is located, the circumference of the test object 10 is preferably 90 to 99 percent of the horizontal plane where the corner 50 is located. The predetermined height is also preferably set to a height where the circumference of the test object 10 is 90 to 99 percent of the horizontal plane where the circumference of the hole 47 is taken as 100 percent. With this configuration, the circumferences are roughly the same, so there is a large overlapping portion on the circumference, and excess penetrant 22 can be effectively removed.

[0038] FIG. 10 also shows that the predetermined height is adjustable. FIG. 10(X) shows the holder 45 for holding the object under test 10 set to the predetermined height a. FIG. 10(Y) shows the holder 45 for holding a spherical object under test 10', which has a different diameter from the object under test 10 and is therefore holding a different type of spherical object under test 10'. In FIG. 10(Y), the predetermined height is b. The reason the predetermined height differs between FIG. 10(X) and FIG. 10(Y) is that the same holder 45 is used to hold the objects under test 10, 10' using holes 47 of the same size, and the predetermined height is adjusted to set the circumference of the cross section of the object under test 10, 10' at the predetermined height to be between 90 percent and 99 percent of the circumference of the hole 47. To adjust the predetermined height to a or b, a spacer (not shown) may be provided between the base 49 and the holder 45. When a spacer is used, the predetermined height is adjusted by replacing it with a spacer of a different height. The predetermined height may be adjusted by vertically raising or lowering the hanger 46, or by any other known method. When the base 49 is filled with the penetrant 21, the predetermined height must be higher than the surface of the penetrant 21. However, this does not apply when the base 49 is made of a flexible material.

[0039] Here, the material used for the base 49 will be described. The base 49 may be made of a material with high friction, such as rubber. This can prevent the object under test 10 from slipping horizontally without rotating when rotating in the α direction. The base may also be made of a flexible material. A flexible material is a material such as felt or sponge that can be indented by placing the object under test 10 on it and that can be impregnated with the penetrant liquid 21. This is preferable because the indentation created by placing the object under test 10 on it increases the contact area and increases friction, and impregnating the soft material with the penetrant liquid 21 can further prevent excess penetrant liquid 22 from being applied.

[0040] 11, the penetrant flaw detection device of the present invention may further include a second holder 51. FIG. 11 is a cross-sectional view of the penetrant flaw detection device of the present invention, taken at the same position as FIG. 5, when the penetrant flaw detection device includes the second holder 51. The second holder 51 may have the same shape as the holder 45 shown in FIGS. 3, 4, 5, 6, etc. That is, the second holder 51 may be flat and have a hole at the same position as the hole 47 of the holder 45, and a gap similar to the gap 48. However, the hole 47 of the holder 45 and the hole of the second holder 51 do not necessarily have to be the same shape or size. The hole of the second holder 51 is smaller than the diameter of the object under test 10, and the second holder 51 holds the object under test 10 at any position in the upper half. In contrast, the hole 47 of the holder 45 is positioned at a predetermined height, which is any position in the lower half of the object under test 10, and holds the object under test 10. By providing the second holder 51, it is possible to prevent the object under test 10 from being held in the hole 47 of the holder 45 by bouncing or the like and escaping.

[0041] 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 to which a surfactant is further added, making 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.

[0042] 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 process does not proceed to the cleaning step 32 until the penetration time has elapsed. This allows the penetrant liquid 21 to penetrate into the defect interior 14. By undergoing the heating step 40 of the penetrant flaw detection method according to this embodiment, this penetration time can be shortened compared to normal. Specifically, what previously required 5 to 10 minutes or more is reduced to approximately 5 to 30 seconds. The use of a heating means is advantageous because it allows the penetrant liquid 21 to sufficiently penetrate into the defect interior 14 even when the penetration time is shortened.

[0043] Next, the cooling step 41 shown in FIG. 1 will be described in detail. The cooling step 41 is preferably performed during the permeation time after the application of the penetrant 21 in the permeation step 31. However, the cooling step 41 may be omitted. In this case, as another example of this embodiment, a permeation time may be provided between the permeation step 31 and the cleaning step 32 during which the cooling step 41 is not performed. Specifically, the cooling step 41 is performed by blowing cold air or pouring room-temperature water or cold water toward the surface 11 and its vicinity where the penetrant 21 is attached, in the state shown in FIG. 2 (X), after the permeation step 31. This creates a cooling effect that cools the surface 11 and the surface vicinity 16. The cooling effect also cools and contracts the air inside the defect 14. As a result, the penetrant 21 is drawn into the defect 14. Because the cooling step 41 creates such a cooling effect, the permeation time from the cooling step 41 to the cleaning step 32 can be shortened. As factors for the cooling effect of cooling the vicinity of the surface 11 and the surface vicinity portion 16, cooling from the inside portion of the inspection object 10 and cooling by the penetrant liquid 21 are also important.

[0044] Next, the cleaning process 32 shown in FIG. 1 will be described. In the cleaning process 32, as shown in FIG. 2(Y), the penetrant 21 has sufficiently penetrated into the defect interior 14 through 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 needs to be removed. Therefore, the cleaning process 32 shown in FIG. 1 removes the penetrant 21 from the surface 11. For this purpose, in the cleaning process 32, steam 82 may be applied to the inspection object 10 as shown in FIG. 12, or a known method such as applying a cleaning liquid to the inspection object 10 may be used. In the case shown in FIG. 12, the inspection object 10 undergoes a loading process and a moving process, similar to the infiltration process 31. During the moving process, cleaning nozzles 81 are positioned directly above and to the side of the inspection object 10 as shown in FIG. 12. The cleaning nozzles 81 positioned to the side are configured to be able to spray toward the portion of the inspection object 10 below the holder 45 positioned at a predetermined height. The cleaning step 21 includes a placing step and a moving step similar to those of the permeation step 31, and in the moving step, steam 82 is sprayed from a cleaning nozzle 81. The steam 82 may be superheated steam. By carrying out the cleaning step 32, the state in which the permeation liquid 21 is applied to the surface 11 of the object to be inspected, as shown in FIG. 2(Y), transitions to the state in FIG. 2(Z), in which excess permeation liquid 21 has been removed.

[0045] Here, the placing step and the moving step, which are also used in the infiltration step 31, the cleaning step 32, the heating step 40, the drying step, etc., will be described in more detail. In the placing step, the holder 45 is positioned at a predetermined height. In common with the above, the predetermined height is a height such that when the object to be inspected 10 is placed on the base 49, the ratio of the circumference of the object to be inspected 10 to the hole 47 being 100% is between 90% and 99%. Furthermore, in common with the placing step, the holder 45 is configured to form a gap 48 when positioned at the predetermined height.

[0046] Next, the moving process will be described in detail. The moving process begins with the holder 45 positioned at a predetermined height in the placing process. In the moving process, for example, as already described, the holder 45 moves linearly in the X direction relative to the base 49, as shown in FIGS. 5 and 8 . FIG. 13 illustrates the relative movement of the holder 45 relative to the base 49 during the moving process, while the holder 45 is positioned at a predetermined height. While FIG. 13 illustrates the relative movement of the holder 45 relative to the base 49, the position of the holder 45 may be fixed, and the base 49 may move in the direction opposite to the arrows 60, 61, 62, 63, and 64 in FIG. 13 . In the moving process, the object under test 10 rolls on the base 49. The base 49 may be configured to have a thin layer of penetrant liquid spread over it, or may be configured to be made of a flexible material impregnated with the penetrant liquid. Therefore, as the object to be inspected 10 rolls on the base 49, the penetrant liquid 21 is applied to the object to be inspected 10.

[0047] The moving step will be described in more detail. The moving step is performed by sequentially performing a first moving step 60, a second moving step 61, a third moving step 62, and a second moving step 61, and these moving steps may be repeated two or more times. The moving step will be described in detail with reference to FIG. 13(X). In the following description of the moving step, horizontal relative movement will be simply referred to as movement, but this always means that the holder 45 moves horizontally relative to the base 49 at a predetermined height.

[0048] In the first moving step 60, the holder 45 is moved linearly in a fixed direction, a distance equal to or greater than the circumferential distance of the object under test 10. While the X direction is shown as the fixed direction in FIG. 13(X), this is merely an example, and any linear movement direction is acceptable. Then, the second moving step 61 is performed. In the second moving step 61, the holder 45 is moved linearly in a direction perpendicular to the fixed direction, which is the movement direction of the first moving step 60, a distance equal to or greater than one-eighth and one-sixth of the circumferential distance. In FIG. 13(X), the second moving step 61 is illustrated as moving linearly in the Y direction, but this is merely an example, and the second moving step 61 is not limited to the Y direction. Next, the third moving step 62 is performed. In the third moving step 62, the holder 45 is moved linearly in a direction opposite to the fixed direction, which is the direction of the first moving step 60, a distance equal to or greater than the circumferential distance. After the third moving step 62, the second moving step 61 is performed again. These steps may be repeated two or more times to thoroughly coat the spherical surface of the test object 10 with the penetrant 21, or to heat the surface or apply steam 82 to perform the cleaning process, etc. Rotating the test object 10 in this manner is advantageous because it allows the penetrant 21 to be thoroughly coated over the entire circumference.

[0049] When the touch valve 70 operates to drip the penetrant liquid 21 toward the center of the object under test 10, the object under test 10 then rotates one and a half times around its circumference, allowing the corners 50 to drip the maximum amount of excess penetrant liquid. Therefore, in the moving step, after the touch valve 70 drips the penetrant liquid 21 onto the center of the object under test 10, it is preferable that the holder 45 moves relatively with the base 49 as the reference for one and a half revolutions around the circumference of the object under test 10.

[0050] Another example of the movement step in the penetrant inspection method according to this embodiment will be described in detail with reference to FIG. 13(Y). Hereinafter, in the description of the movement step, horizontal relative movement will be simply referred to as "movement," but all of these terms equally refer to horizontal relative movement of holder 45 at a predetermined height with base 49 as the reference. As shown in FIG. 13(Y), the movement step first includes a first movement step 60. In the first movement step 60, holder 45 is moved linearly in a fixed direction by a distance equal to or greater than the circumferential distance of object 10 to be inspected. While the X direction is shown as the fixed direction in FIG. 13(Y), the X direction is merely an example, and any linear movement is acceptable.

[0051] Thereafter, a fourth movement step 63 is performed. In the fourth movement step 63, the object 10 is moved linearly in a direction that forms an acute angle with the constant direction of the first movement step 60, over a distance equal to or greater than the circumferential distance of the object 10. The acute angle may be, for example, approximately 5 to 30 degrees. After the fourth movement step 63, a fifth movement step 64 is performed. In the fifth movement step 64, when an imaginary line is drawn in the direction opposite to the constant direction of the first movement step 60, the object 10 is moved linearly in a direction that forms an acute angle with the imaginary line, over a distance equal to or greater than the circumferential distance of the object 10. The acute angle may be, for example, approximately 5 to 30 degrees. In the movement step, these steps may be repeated two or more times to evenly apply the penetrant liquid 21 to the spherical surface of the object 10, or to apply heat or steam 82 to the spherical surface. This is advantageous because the penetrant liquid 21 can be applied to the entire circumference by rotating the object 10.

[0052] 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 presence of the penetrant 21 is difficult to detect with the naked eye. Therefore, a white inorganic fine powder or a dispersion of the 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, which are well known for use in developers. The uniform, thin layer of white inorganic fine powder formed on the surface 11 then causes capillary action, sucking out the penetrant 21 from inside the defect 14, thereby forming a rainbow pattern (indicator pattern). This indicator pattern magnifies the defect opening 13, facilitating detection with the naked eye and improving detection accuracy.

[0053] However, the penetrant flaw detection 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 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 desirable to use a fluorescent penetrant for ease of observation in the observation step 34, but the method is not limited to this.

[0054] Next, in the observation step 34 shown in FIG. 1, the indication pattern can be observed by visual inspection or by using known means such as a method using a fluorescent penetrant and a black light in a dark room, or a method of taking an image using an imaging device and inspecting it.

[0055] The penetrant flaw detection device of the present invention may be provided with a penetrant means, a cleaning means, and an observation means, and preferably includes a heating means or the like for further performance enhancement. A cleaning means may be provided for performing a cleaning step 32 to remove the penetrant liquid 21 from the object under test 10. Subsequent steps may include a developing means for performing a developing step 33 and an observation means for performing an observation step 34. However, since a non-developing method is available, a developing means may not be provided. The cleaning means is preferably a mechanism for applying a cleaning liquid to the object under test 10 by spraying or coating, etc. The developing means is preferably a spraying or coating device for applying a developer or developing solution to the surface 11 of the object under test 10. The observation means is preferably composed of an imaging means for capturing still or moving images, a recording medium, a display medium, etc., although known devices may be used for each of these.

[0056] In the heating step 40, the surface vicinity 16 is heated first. Then, the air on the surface 11 adjacent to the surface vicinity 16 and the air inside the defect 14 are heated. As a result of the air being heated, when the state shown in FIG. 2(X) is reached in the penetration step 31 shown in FIG. 1, the air remaining inside the defect 14 is heated. During the penetration time, this heated air is cooled and contracts due to the cooling effects of cooling from the inside of the object 10, cooling by the penetrant liquid 21, and cooling by the cooling step 41. The contraction of the air inside the defect 14 acts to draw the penetrant liquid 21 into the defect 14, thereby shortening the penetration time required for the penetrant liquid 21 to penetrate into the defect 14.

[0057] Next, the relationship between performing the heating step 40 and the accelerated penetration time will be explained. When the surface 11 is heated to 50 degrees Celsius in absolute temperature using a heating means in the heating step 40, theoretically, if air at 25 degrees is heated by 50 degrees in the heating step 40, for example, the volume will expand, increasing by 17 percent. In this state, the penetration step 31 is performed and the penetrant liquid 21 is applied to the surface 11. Then, in addition to the force of the penetrant liquid 21 itself trying to enter the defect interior 14, the volume of the air inside the defect 14, which had expanded by 17 percent, returns to its original state as the temperature approaches room temperature, decreasing by approximately 17 percent. This allows a large amount of the penetrant liquid 21 to be drawn into the defect interior 14 instantaneously.

[0058] Next, the penetrant flaw detection device of the present invention will be further described. The penetrant flaw detection device 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. The penetrating means may include a holder 45 and a base 49, with the holder 45 at a predetermined height relative to the base 49 and movable horizontally relative to the base 49, and the base 49 may be made of a flexible material. The cooling means may be a known device for blowing cold air or immersing the object under test in cold water. The cleaning means may include a holder 45 at a predetermined height relative to the base 49 and movable horizontally relative to the base 49, and may include cleaning nozzles 81 arranged directly above and to the side to spray steam 82 onto the object under test 10, as shown in FIG. 12 . The developing means may be a device for applying a developer to the object 10, and the observing means may be a visual observation or a video or still image capturing device, etc. Any known means may be used for each. The penetrant flaw detection device of the present invention may be designed as appropriate so that the penetrant flaw detection method of the present invention can be carried out.

[0059] The penetrant flaw detection device of the present invention may further include a transport means. The transport means includes a holder 45 and a hanger 46, etc. The transport means may further include a second holder 51. In the penetrant flaw detection method according to this embodiment, the transport step is performed using this transport means. In the penetrant flaw detection method, the holder 45 is positioned at a predetermined height and loosely holds the object 10 to be inspected. The holder 45 is then raised to a predetermined height or higher. The object 10 then fits into the hole 47 and is firmly held. The object 10 is then moved to the cooling step area where the next step, the cooling step 41, is performed, and the placement step is performed again. The same transport steps are also performed using the same transport means when moving from the heating step area where the heating step 40 is performed to the penetrating step area where the penetrating step 31 is performed; when moving from the penetrating step area where the penetrating step 31 is performed to the cleaning step area where the cleaning step 32 is performed without passing through the cooling step 41; and when moving from the cleaning step area where the cleaning step 32 is performed to the developing step area where the developing step 33 is performed.

[0060] The transport means and transport process provided in the penetrant inspection device and penetrant inspection method of the present invention make it possible to carry out all penetrant inspections while the object to be inspected 10 is held in the holder 45, which is preferable as it eliminates the need for unnecessary work such as transferring the object to be inspected 10. The heating process area, penetrant process area, cooling process area, and cleaning process area each have a separate base 49, and it is preferable to use a flexible member in the penetrant process area. In the heating process area, cooling process area, and cleaning process area, it is preferable to use a member made of rubber or the like.

[0061] The present disclosure can be suitably used for inspecting flaws in spherical objects, such as balls made of non-magnetic materials, as the object 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]

[0062] 10. Inspection object 11, surface 12. Scratches 13. Defective opening 14. Inside the defect 16. Near surface 21, Penetration liquid 22. Excess penetrant 31, Penetration process 32. Cleaning process 33, Development process 34. Observation process 40,Heating process 41, Cooling process 45, Holder 46. ​​Hanger 47, Hole 48, Gap 49, bass 50, corner 51, second holder 60, first operation (first movement process) 61, second operation (second movement process) 62, third operation (third movement process) 63, fourth operation (fourth movement process) 64, Fifth movement (fifth movement process) 70. Touch valve 71, pipe section 72, O-ring 73, Piston 74, Piston tip 81, cleaning nozzle 82. Steam

Claims

1. In a penetrant inspection device capable of carrying out a penetrant step of applying a penetrant liquid to the surface of a spherical object to be inspected or a cleaning step of removing the penetrant liquid, the penetrant inspection device further comprises a holder having a circular hole for holding the object to be inspected, and a flat base on which the object to be inspected can be placed, and the holder is configured to be able to be held at a predetermined height relative to the base, the predetermined height is a height at which, when the holder is positioned at the predetermined height relative to the base, the object under test held by the holder comes into contact with the base and a gap is formed between the circular hole of the holder and the object under test; The penetrant flaw detection device is characterized in that the holder is configured to be movable approximately horizontally and relatively with respect to the base when the holder is positioned at the predetermined height relative to the base.

2. the diameters of the objects to be inspected held simultaneously by the holder are the same; 2. The penetrant flaw detection device according to claim 1, wherein when the holder holds the test objects having different diameters, the predetermined height is adjustable in accordance with the diameter of the test objects.

3. 2. The penetrant flaw detection device according to claim 1, wherein the base is made of a flexible material that is flexible enough to allow a recess to be formed under the weight of the test object and that can be impregnated with the penetrant liquid.

4. A penetrant flaw detection method using the penetrant flaw detection device according to claim 1, The penetrant flaw detection method includes at least the penetrating step, A penetrant flaw detection method, characterized in that the penetrant liquid is dropped onto the center of each test object in the penetrating step.

5. A penetrant flaw detection method using the penetrant flaw detection device according to claim 1, The penetrant flaw detection method includes a moving step, the moving step including a first moving step, a second moving step, and a third moving step, the first moving step, the second moving step, and the third moving step are all steps in which the holder is held at the predetermined height and moves approximately horizontally relative to the base, the first moving step is a step of linearly moving the holder in a fixed direction over a distance equal to or greater than the circumferential distance of the object to be inspected, the second moving step is a step of linearly moving the holder in a direction perpendicular to the certain direction on a horizontal plane, the third moving step is a step of linearly moving the holder in a direction opposite to the fixed direction on a horizontal plane by a distance equal to or greater than the circumferential distance of the object to be inspected, The penetrant flaw detection method is characterized in that the moving process is a process in which the first moving process is followed by the second moving process, the third moving process, and the second moving process are carried out in that order, and the moving process is repeated two or more times.

6. A penetrant flaw detection method using the penetrant flaw detection device according to claim 1, the penetrant flaw detection method includes a transporting step of transporting an object to be inspected from a penetrating step area for carrying out the penetrating step to a cleaning step area for carrying out the cleaning step after the penetrating step, the conveying step includes lifting the holder, which is positioned at the predetermined height relative to the base, from the predetermined height, so that the object to be inspected can be fitted into the holder and conveyed; The penetrant inspection method further includes a heating step of increasing the surface temperature of the object to be inspected, 10. The penetrant inspection method, wherein the cleaning step involves cleaning the surface of the object to be inspected with steam.

Images