JPH04140651A - Method for penetration test and penetrant used for the method - Google Patents

Abstract

PURPOSE:To enable highly accurate probing without causing pollution by performing penetration treatment using penetrant which is not compatible with water and does not contain base solvent with specific gravity less than 1 and surfactant such as diluent and by repetitively using water with the penetrant separated to blow it with a specific water pressure to perform cleaning. CONSTITUTION:After penetrant is applied on a surface of a specimen to be inspected and penetrated into a defect part to perform penetration treatment, cleaning treatment is performed wherein excessive penetrant which remains is cleaned off by using water. Then, after the specimen is dried, probing of the defect part is done. Penetration treatment is performed by using penetrant which is not compatible with water and which does not surfactant comprising base solvent with specific gravity less than 1 at normal temperature, similar diluent and oil soluble fluorescent dye. Cleaning treatment is performed by repetitively using water with the penetrant separated by a difference in specific gravities from the water container excessive penetrant caused by the cleaning so that the water is blown against the surface of the specimen to be inspected at a water pressure of at least 6 kg/cm<2> or higher. Thus pollution is not caused while highly accurate probing is possible.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a penetrant test method and a penetrant liquid used in the method, which does not cause pollution problems due to cleaning waste liquid generated during cleaning processing, and which The present invention provides a penetrant test method that provides highly accurate flaw detection results.

Further, the present invention provides a penetrant liquid for penetrant testing methods that can be used even at low temperatures.

[Conventional technology]

As is well known, penetrant testing methods have been widely used for a long time to detect defects such as minute racks and minute pinholes that exist on the surfaces of various equipment and parts.
It has also been standardized in S-Z 2343-1982J.

The basic method is to apply a highly penetrating liquid made by dissolving an oil-soluble visible or fluorescent dye in a solvent to the surface of the object to be inspected, and then penetrate the defective area. Remove the excess penetrating liquid remaining on the surface of the test object without
The presence of a defect is detected using a penetrating liquid that has penetrated into the defect.

The above-mentioned penetrant testing method has various specific aspects depending on the type of penetrant used and the type of treatment means for removing excess penetrant.
-37501 Publication (hereinafter referred to as "1st Publication") and Special Publication No. 59-28860 (hereinafter referred to as "2nd Publication")
There is a penetrant testing method that adopts the following specific aspects as disclosed in .

That is, in the first publication, an oil-based penetrant containing no surfactant, which is made of an oil-based solvent that is not compatible with water and an oil-soluble fluorescent dye, is used as the penetrating liquid, and the excess penetrating liquid is removed. A penetrant test method is disclosed in which water vapor is sprayed onto the surface of the test object at a spray pressure of 0.1 to 5 kg/Ci as a treatment means, and the second publication discloses that a hydrophobic penetrant is used as a penetrating liquid. A penetrant test method has been disclosed in which water is sprayed onto the surface of an object to be inspected at a water pressure of 0.5 to 4 kg/cd as a treatment means for removing excess penetrating liquid.

The first publication states, ``Waste liquid can be easily separated from oil and water.''
(First Publication, Column 8, Lines 19-20), and the Second Publication states: 1. The permeate liquid can be easily separated from the water due to the difference in specific gravity of the water bar, and by standing still, the permeate liquid and water can be separated in a short time.'' (Second
According to the penetrant test method (hereinafter referred to as "known penetrant test method") disclosed in the first and second publications of Doyo, as stated in Column 3, lines 14 to 16 of the publication, excessive penetration Since the permeate can be separated from the water (waste liquid) containing surplus permeate generated by the cleaning process in which the liquid is washed and removed using water, by oil-water separation based on the difference in specific gravity, the treatment of the cleaning waste liquid becomes easy and there is no problem with pollution. It is said that it does not cause

Regarding the penetrant liquid used in the known penetrant testing method, the first publication states that ``specifically, it may be selected from commercially available oil-based penetrant liquids'' (column 7, lines 17-18 of the first publication), and that ``alkylbenzene , a commercially available fluorescent oil-based penetrating liquid 0D-6000 (trade name: manufactured by Tokushu Toyo Co., Ltd.) consisting of vegetable oil and fluoro-lure GA' (first publication, column 8, lines 39-42), and the second publication mentions '"It does not contain a surfactant that imparts emulsifying properties and is made by adding an oil-soluble organic fluorescent dye or a red dye to highly permeable mineral oil" (No. 2 Publication No. 2, column 3, lines 33-35).

Incidentally, the general formulation of commercially available surfactant-free oil-based fluorescent penetrants includes 2 to 5 parts of an oil-soluble fluorescent dye, a base solvent for dissolving the dye (high-boiling esters, high-boiling alcohols, polyhydric 10 to 40 parts of alcohol (conductor, etc.) and 50 to 90 parts of a diluting solvent (chain or ring-t hydrocarbon, etc.).

[Problem to be solved by the invention]

As mentioned above, the present inventor has discovered that, according to the known penetrant testing method, it is possible to separate the penetrating liquid from the water containing the surplus penetrating liquid produced by the cleaning process by separating the penetrating liquid based on the difference in specific gravity. Focusing on this fact, we came up with the idea of performing spring purification treatment by repeatedly using water from which the permeate has been separated from shellfish, which saves resources and reduces cleaning treatment costs.

Moreover, in embodying the above idea, the present inventors have developed a method using water vapor that uses water vapor, rather than the means using water vapor disclosed in the first publication.
The means of spraying water disclosed in the gazette is equipment,
It was judged to be advantageous in terms of operability, water circulation line setting, etc.

Therefore, when we conducted experiments using all of the commercially available oil-based fluorescent penetrants that do not contain surfactants, including the penetrants exemplified in the first and second publications, we found the following problems. I learned that there is.

That is, the first problem is that it takes approximately 30 to
The second problem is that spraying with a water pressure of about 0.5 to 4 kg, as taught in the second publication, cannot sufficiently wash away the excess penetrant, resulting in poor accuracy. The problem is that high flaw detection results were not obtained.

Therefore, in view of the above-mentioned problems, the present invention establishes a technical means that makes it possible to quickly separate the permeate from water containing excess permeate generated by cleaning treatment by oil-water separation at room temperature. A new type of penetrant flaw detection that enables repeated use of the water from which the penetrant has been separated during the cleaning process and provides high flaw detection results by establishing a technical means that can sufficiently wash excess penetrant liquid by spraying and obtain highly accurate flaw detection results. The technical challenge is to provide a test method.

Furthermore, in the process of completing the present invention, the inventor
We conducted various studies on the formulation of oil-based fluorescent penetrants that do not contain surfactants, and found that increasing the amount of oil-soluble fluorescent dye dissolved would improve the indication of defective areas. It was learned that fluorescent dyes tend to precipitate in the penetrant solution at low temperatures. For example, in the case of nuclear reactor equipment, it is necessary to perform penetrant testing at a low temperature of about -15°C, but in such cases, the amount of dissolved fluorescent dye is reduced to better indicate the defective area. Even if an attempt is made to use an increased amount of penetrant, there is a problem in that the fluorescent dye will precipitate.

Therefore, in view of the above-mentioned problems, the present invention has established a technical means that can obtain a good indication of defective parts without increasing the amount of dissolved fluorescent dye, and has developed an oil-based dye that can be used even at a low temperature of about -15°C. The technical problem is to provide a fluorescent penetrant.

[Means to solve the problem]

Each of the above technical problems can be achieved by the present invention as follows.

■ Apply a penetrating liquid containing no surfactants to the surface of the test object, consisting of a base solvent that is not compatible with water, a diluent solvent that is not compatible with water, and an oil-soluble fluorescent dye. Then, a cleaning treatment is performed to remove excess penetrating liquid remaining on the surface of the object to be inspected without penetrating into the defective part by washing with water. In a penetrant test method in which the presence of a defect is detected using a penetrant liquid that has permeated into the defect after drying the surface of the object to be inspected, the penetrant treatment is carried out using water that is compatible with water. Specific gravity 1 at normal temperature
carried out using a penetrating liquid consisting of a base solvent of less than 1,000 ml, a diluent having no compatibility with water and a specific gravity of less than 1 at room temperature, and an oil-soluble fluorescent dye, and containing no surfactant,
The cleaning treatment is applied to the surface of the object to be inspected at a rate of at least 6 kg/cm.
Water is sprayed at a water pressure of m2 or more, and the spraying is carried out by repeatedly using water that has been separated from water containing surplus permeate generated by cleaning treatment by oil-water separation based on the difference in specific gravity. Penetrant testing method.

2. Consisting of a base solvent that is not compatible with water and has a specific gravity of less than 1 at room temperature, a diluent solvent that is not compatible with water and has a specific gravity of less than 1 at room temperature, and an oil-soluble fluorescent dye; A penetrant liquid for a penetrant test method that does not contain a surfactant, wherein the base solvent is dioctyl phthalate or trioctyl phosphate, and the diluent solvent is an aromatic solvent.

3. It has no compatibility with water and has a specific gravity of 1 at room temperature.
10 to 40 parts of a base solvent of less than 10 to 40 parts, and a diluent solvent of 50 to 90 parts that has no compatibility with water and has a specific gravity of less than 1 at room temperature.
In the penetrant liquid for a penetrant test method, which contains 2 to 5 parts of oil-soluble fluorescent dye and does not contain a surfactant, the base solvent is dioctyl phthalate or trioctyl phosphate, and the diluent solvent is an aromatic solvent. , the oil-soluble fluorescent dye is Florescent Bright Varnish Agent 7.
5 (trade name: manufactured by Morton Co., USA) or Florescent Bright Varnish Agent 68 (trade name: manufactured by Coromoto Kayaku), and as a fluorescence brightness enhancer, it is a fluorescent dye with a carbon number of 6 to 14 that is difficult to dissolve. A penetrant liquid for penetrant testing methods, characterized in that an aliphatic solvent or mineral oil is added.

The configuration of the present invention will be explained in more detail as follows.

First, the base solvent used in the present invention, which is not compatible with water and has a specific gravity of less than 1 at room temperature, can be easily obtained from commercial products, and among them, trioctyl phosphate (
TOP/specific gravity 0.920), tributyl phosphate (TB
P・specific gravity 0.978), dioctyl phthalate (DO
P・specific gravity 0.982), dibutyl malate (DBM・
specific gravity 0.997), ditridecyl phthalate (DTDP)
・Specific gravity 0.953), dinonyl phthalate (DNP・specific gravity 0.970), dioctyldodecanedioate (D
OD D/specific gravity 0.910), dioctyl fumarate (DOF/specific gravity 0.942), etc. can be suitably used.

In the present invention, the diluting solvent that is not compatible with water and has a specific gravity of less than 1 at room temperature can be easily obtained from commercial products, and among them, aromatic solvents, especially xylene,
Dimethylnaphthalene, creosote oil, Tsurubento naphtha, Tsurupetz 100 (product name: Exxon), Tsurupetz 150 (product name: Exxon), KMC11
3 (trade name, manufactured by Niriha Co., Ltd.), etc. can be suitably used.

As the oil-soluble fluorescent dye in the present invention, commercially available products conventionally used as oil-based fluorescent penetrants can be used. Among them, Fluorescent Bright Varnish Agent 75 (trade name: manufactured by Morton Co., Ltd., USA) and Fluorescent Bright Varnish Agent 68 (trade name: Nippon Kayaku) can be suitably used.

The penetrating liquid according to the present invention is easy to prepare, and the mixing ratio of each material may be the same as that in the general formulation of the commercially available oil-based penetrating liquid that does not contain a surfactant. 10 to 40 parts of base solvent,
It can be prepared by mixing 50 to 90 parts of a diluting solvent and 2 to 5 parts of an oil-soluble fluorescent dye, stirring the materials, and heating if necessary to dissolve the dye.

In addition, as a prescription for the penetrating liquid in the present invention, from each of the above materials, dioctyl phthalate or trioctyl phosphate is used as the base solvent, an aromatic solvent is used as the diluting solvent, and Florescent Bright Varnish Agent 75 (same as above) is used as the oil-soluble fluorescent dye. Or, when selecting Florescent Bright Varnish Agent 68 (same as above) and setting the base solvent and diluent solvent in the mixing ratio within the above range, an aliphatic solvent or mineral having 6 to 14 carbon atoms in which the dye is hardly soluble. By adding oil as a fluorescence brightness enhancer, even if the amount of dye used is 2 to 3 parts, sufficient fluorescence brightness can be obtained to clearly indicate defective areas.

The above-mentioned aliphatic solvents having 6 to 14 carbon atoms and mineral oils can be easily obtained from commercial products, and among them, hexane,
Heptane, octane, Isopar G (trade name: manufactured by Exxon), No. 0 Solvent M (trade name, manufactured by Coromoto Sekiyu), etc. can be suitably used.

The amount added is 5 to 30% by volume (hereinafter referred to as "%"), preferably 10 to 20%, based on the target penetrating liquid of the above formulation. If it is less than 5%, no remarkable brightness improvement effect can be obtained, and if it exceeds 5%, the fluorescence brightness increases in proportion to the amount added, reaching a peak between about 10 and 20%, and about 30%.
If it exceeds %, it will drop dramatically.

Figure 1 is a graph showing the relationship between the fluorescence brightness of a defect indicating pattern and the amount added. When heptane is added, as seen by the solid line in the figure, the defect indicating brightness is lower than when no heptane is added. If it is 100, it becomes about 115 when 10% addition is about 118.20% addition and about 125.30% addition is about 122.40% addition. The present inventors are hexane, octane, Isopar G (same as above), Solvent No. 0 M (same as above)
It has been confirmed that almost the same tendency is observed in the case of

Further, in a penetrating liquid in which 2 to 3 parts of an oil-soluble fluorescent dye is dissolved, the dye does not precipitate even at -15 to -16°C, for example.

Incidentally, after the penetrating liquid according to the present invention is prepared, it can be used as an aerosol type by being sealed in an aerosol can together with a propellant according to a conventional method.

Next, the penetrant treatment and drying treatment in the present invention are completely similar to the operating modes employed in conventional penetrant testing methods.

The cleaning treatment in the present invention must be carried out by spraying water at a water pressure of at least 6 kg/1ff1 onto the surface of the object to be inspected after the penetration treatment. When using water pressure of 6 kg/d or higher, excess penetrating liquid can be sufficiently washed away and highly accurate flaw detection results can be obtained. The higher the water pressure, the shorter the cleaning time, for example 20kg/ci.
If the water pressure is set to about 30 seconds, sufficient cleaning can be achieved. However, if the pressure is too high, there is a risk of over-cleaning and removing even the penetrating liquid in the defect area, but the inventor has found that even with a water pressure of 60 kg/d, over-cleaning does not occur and high accuracy is achieved. It has been confirmed that flaw detection results can be obtained. Taking cleaning time, equipment, etc. into consideration, a water pressure of about 10 to 30 kg/ad is practical. For spraying water, a well-known high-pressure pump and spray nozzle may be used.

In the cleaning process of the present invention, water containing excess permeate generated by the cleaning process is collected, and the water from which the permeate is separated by oil-water separation based on the difference in specific gravity is repeatedly used for cleaning. In this case, separation of the permeate can be achieved by keeping it stationary for 3 to 6 minutes at room temperature.

Of course, the separated penetrant liquid can be reused if it is not contaminated by dust attached to the object to be inspected or dust around the testing area, but if it is heavily contaminated, it may be burned. It can be easily processed by

[Effect]

As mentioned above, the present inventor used all of the commercially available oil-based fluorescent penetrants that do not contain surfactants, including the penetrants exemplified in the first and second publications, As a result of many repeated experiments on the separation of penetrant liquid by oil-water separation under standing conditions, we found that the reason why conventional oil-based fluorescent penetrant liquids require a long time of approximately 30 minutes or more for separation is because the specific gravity is 1. For example, diethyl phthalate (DEP, specific gravity 1.120
), tricresyl phosphate (TCP, specific gravity 1.170
), etc., so I learned that the cause is that the specific gravity of the penetrating liquid itself is 1 or more, or almost 1.

In the present invention, the penetrating liquid includes a base solvent that is not compatible with water and has a specific gravity of less than 1 at room temperature, a diluent solvent that is not compatible with water and has a specific gravity of less than 1 at room temperature, and Since the formulation is made of oil-soluble fluorescent dye and does not contain surfactants, the specific gravity of the penetrating liquid itself is less than 1, so if it is left standing for 3 to 6 minutes at room temperature,
Easily separated from water by oil/water separation based on the difference in specific gravity.

In addition, in the present invention, in the cleaning process, 6 kg/a
Since water is sprayed at a high water pressure of at least 100 kg/car, preferably 10 to 30 kg/car, excess penetrating liquid remaining on the surface of the object to be inspected can be sufficiently washed away.

Although it has not yet been possible to theoretically elucidate the phenomenon in which over-washing does not occur even with high water pressure of 10 to 30 kg/at/, the inventor believes that this is due to the fact that the specific gravity of the penetrating liquid itself is less than 1. I think of it as something.

In addition, in the present invention, when the above-mentioned aliphatic solvent having 6 to 14 carbon atoms or mineral oil is added to the penetrating liquid with a specific prescription, the fluorescence brightness indicating the defective part increases. Unfortunately, this has not yet been possible, but as shown in the Examples below, it can be guaranteed that the effect of improving fluorescence brightness can be reliably obtained.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

1. Preparation of penetrant A, 20 parts of dioctyl phthalate (manufactured by Ohe Kagaku), 77 parts of Tsurupez 150 (same as above), 1 part of Florescent Bright Varnish Agent 75 (same as above), and 1 part of Florescent Bright Varnish Agent 68 (same as above). ) mix 2 parts,
A penetrating solution A was obtained by stirring. The specific gravity of this permeate is 0.91
1 (25°C).

B, mixing 30 parts of octyl phosphate (manufactured by Daihe Kagaku), 67 parts of Tsurpez 150 (same as above), 1 part of Florescent Bright Varnish Agent 75 (same as above) and 2 parts of Florescent Bright Varnish Agent 68 (same as above); Penetration liquid B was obtained by stirring. The specific gravity of this permeate is 0.901 (2
5°C).

C, 17 parts of dioctyl phthalate (same as above), 68 parts of Tsurupez 150 (same as above), 10.5 parts of Isopar G (same as above)
0.9 parts of Florescent Bright Varnish Agent 75 (same as above) and 1.6 parts of Florescent Bright Varnish Agent 68 (same as above) were mixed and stirred to obtain a penetrating liquid C. The specific gravity of this permeate is 0.890 (25°C).

D, 10 parts of octyl phosphate (same as above), 150 parts of Tsurpets
(same as above), 19 parts of Isopar G (same as above), 1 part of Florescent Bright Varnish Agent 75 (same as above), and 2 parts of Fluorescent Bright Varnish Agent 68 (same as above) were mixed and stirred to obtain a penetrating liquid. Ta.

2. Oil-water separation test results Weigh out 2 cc of each of the above-mentioned permeate liquids A-D, put 2 cc of permeate liquid and 20 cc of water into a 180 mm long screw test tube, and conduct each test at 25°C. After shaking the tube for 5 seconds, the tube was allowed to stand still, and an oil-water separation test was conducted by measuring the time from the end of shaking until the tube became transparent at a height of 20 mm from the bottom of the test tube.

For comparison, 0D-1700A (trade name: manufactured by Marktic ■), which is a commercially available oil-based penetrating liquid that does not contain a surfactant, was used.
and 0D-6000 (trade name: manufactured by Marktic ■) were also subjected to an oil-water separation test using the same method as above.

The results showed that the permeate solutions A-D became clear in 4 minutes, but 0D
-1700A (same as above) and 0D-6000 (same as above) remained cloudy even after 30 minutes.

3. Implementation of penetrant test method The following penetrant test method was carried out using each of the above penetrants A to D.

JrS-Z-2343-1982 standard B type test piece (warp depth: 50μ) was subjected to ultrasonic cleaning in acetone 3.
After pre-treatment for 0 minutes, a penetrating solution is applied to the test surface using a brush and left for 5 minutes for a penetrating treatment. and a spray with a nozzle hole diameter of 1 mm,
Water pressure 20kg/al, water flow 41/min, spray angle 2
A cleaning process was performed by spraying water for 30 seconds at a hand blowing angle of 5 degrees, followed by a drying process in which the specimen was dried at 80°C for 2 minutes, and then exposed to an ultraviolet lamp (black light) in a dark place.
Visually observe the test surface under irradiation.

Incidentally, the water containing the surplus permeate generated in the cleaning process is allowed to stand at room temperature for 5 minutes, and the permeate is separated by oil-water separation, and then used again for cleaning.

As a result, a defect-indicating fluorescent pattern was clearly visible to the naked eye on the test surface when any of the penetrants A to D was used.

In addition, oil-water separation of water containing excess penetrating liquid proceeded smoothly after 5 minutes of standing, and clear water could be repeatedly used for cleaning.

Although this embodiment shows an embodiment in which a known developer is not used, it goes without saying that the present invention can also be practiced in an embodiment in which a known developer is used.

4. Fluorescence brightness improvement test result To the above penetrant A, 10% heptane by volume, 2
Penetrant solutions A1 to A4 were prepared by adding 0%, 30%, and 40%. The specific gravity of each of the penetrating liquids A1 to 4 is 0 for A1.
．． 889, A2 is 0.867, A3 is 0.845, A4
is 0,823.

In addition, 10% of heptane was added in a volume ratio to the above-mentioned penetrating solution B.
%, 20%, 30%, 40%, penetrant B1~
4 was prepared. The specific gravity of the penetrating liquids B1 to B4 is B
1 is 0.895, B2 is 0.878, B3 is 0.862
, B4 is 0.846.

Using the penetrant liquids A1 to 4 and B1 to 4, the penetrant test method was carried out under the same conditions as in "3. Implementation of the penetrant test method" above, and the fluorescence of each defect indicating fluorescent pattern was The luminance was measured using a photomultiplier tube (manufactured by Hamamatsu Photonics) with a field of view area of the light receiving slit of 2 mm.
It was measured at 2-.

The results showed that, regardless of whether penetrants A1-4 or B1-4 were used, a clear defect-indicating fluorescent pattern could be seen with the naked eye on the test surface, indicating that the water containing excess penetrant generated during the cleaning process was clearly visible to the naked eye. The state of oil-water separation was also the same as in the case of using penetrants A-D.

The relationship between the amount of heptane added and the fluorescence brightness of the defect indicator pattern is shown in Figure 1 for penetrant A I-4, and for penetrant B
1 to 4 are as shown in FIG.

In addition, both Figures 1 and 2 show the fluorescence brightness of each defect indicating fluorescent pattern (by the same measurement method as above) when using penetrant A1 and penetrant B in "3. Penetrant testing method" above. 1
It was created as 00.

In addition, in Figure 1, Isopar G (same as above) is added at a volume ratio of 10%, 20%, 30%, and 40% to the above-mentioned penetrating liquid A.
The results were also shown when measuring in the same manner as in the case of penetrants A1 to 4 using the penetrant solution prepared by adding
(dotted line in Figure 1).

5. Dye precipitation test for penetrant solutions The above penetrant solutions A to D were left at -16°C for one month, but no dye precipitation was observed in any of the penetrant solutions.

〔Effect of the invention〕

According to the present invention as described above, it is possible to implement a penetrant flaw detection test method that does not cause pollution problems due to cleaning waste liquid generated during the cleaning process and can provide highly accurate flaw detection results.

That is, in the present invention, the permeate can be separated from the water containing the surplus permeate generated during the cleaning process in a short time of 3 to 6 minutes at room temperature, allowing efficient repeated use of water. Therefore, the penetrant testing method can be carried out using a closed loop method that does not generate cleaning waste fluid. In addition, in the present invention, 6 kg
Since water can be sprayed at a high pressure of /cm or more for cleaning, sufficient cleaning can be performed and there is no over-cleaning, making it possible to obtain highly accurate flaw detection results.

Furthermore, since the penetrant liquid according to the present invention does not precipitate dye even at a low temperature of -15 to -16°C, the range of application of the penetrant test method can be expanded.

[Brief explanation of the drawing]

FIGS. 1 and 2 are graphs showing the relationship between the fluorescence brightness of a defect indicating pattern and the amount added to explain the effect of adding the fluorescence brightness enhancer in the present invention. In FIG. 1, the solid line shows the case of hebutane, and the dotted line shows the case of Isopar G. In FIG. 2, the solid line represents hebutane.

Claims (1)

[Scope of Claims] 1. A penetrating liquid consisting of a base solvent that is not compatible with water, a diluent solvent that is not compatible with water, and an oil-soluble fluorescent dye, and does not contain a surfactant. A penetrating treatment is performed in which the penetrant is applied to the surface of the object to be inspected and penetrates into the surface opening defects (hereinafter referred to as "defects"), and then the excess remaining on the surface of the object without penetrating into the defects is removed. Penetrant testing involves performing a cleaning process to remove the penetrating liquid using water, followed by a drying process to dry the surface of the object to be inspected, and then detecting the presence of defects using the penetrating liquid that has penetrated into the defective area. In the method, the infiltration treatment is performed using a base solvent that is not compatible with water and has a specific gravity of less than 1 at room temperature, a diluent solvent that is not compatible with water and has a specific gravity of less than 1 at room temperature, and an oil-soluble solvent. The cleaning treatment is carried out using a penetrating liquid consisting of a fluorescent dye and containing no surfactant, and the cleaning treatment is carried out by spraying water onto the surface of the object to be inspected at a water pressure of at least 6 kg/cm^2 or more, and the spraying is accompanied by cleaning. 1. A penetrant test method characterized by repeatedly using water containing excess penetrant generated by treatment, from which the penetrant is separated by oil-water separation based on a difference in specific gravity. 2. It has no compatibility with water and has a specific gravity of 1 at room temperature.
In a penetrant liquid for a penetrant test method that does not contain a surfactant and does not contain a surfactant, the base solvent is incompatible with water and has a specific gravity of less than 1 at room temperature. is dioctyl phthalate or trioctyl phosphate, and the diluting solvent is an aromatic solvent. 3. It has no compatibility with water and has a specific gravity of 1 at room temperature.
less than 10 to 40 parts by weight (hereinafter referred to as "parts") of a base solvent, which has no compatibility with water and has a specific gravity of 1 at room temperature.
less than 50-90 parts of diluting solvent and 2-5 parts of oil-soluble fluorescent dye
A penetrant liquid for a penetrant testing method that does not contain a surfactant, wherein the base solvent is dioctyl phthalate or trioctyl phosphate, the diluent solvent is an aromatic solvent, and the oil-soluble fluorescent dye is fluororesin. St. Bright Varnish Agent 75 (trade name: manufactured by Morton Co., Ltd., USA) or Florescent Bright Varnish Agent 68 (trade name: manufactured by Nippon Kayaku Co., Ltd.) is used as a fluorescent brightness enhancer, and the number of carbon atoms in which the fluorescent dye is hardly soluble 1. A penetrant liquid for penetrant testing, characterized in that an aliphatic solvent or mineral oil of 6 to 14 is added.