JP5093574B2 - Penetration testing method - Google Patents

Description

The present invention relates to a penetrant flaw detection test method applied to flaw detection of fine opening defects existing on the surface of various members such as automobile members, and a water-washable water-based penetrant used in the penetrant flaw detection test method.

  As is well known, the penetrant testing standardized in “JIS Z 2343-1 to 4: 2001”, which is a kind of non-destructive inspection method, exists on the surface of various members such as automobile members (for example, piston rods). It is widely used for flaw detection of fine opening defects (for example, fine cracks and pinholes), and its basic mode is dyed penetrant (usually oil-soluble red as shown in the JIS standard). A highly penetrating liquid in which a dye is dissolved in a solvent is used) or a fluorescent penetrating liquid (usually ultraviolet light: black light: penetrating oil-soluble fluorescent dye that emits yellow-green fluorescence under irradiation in a solvent) A strong liquid is used) is adhered to the surface of the object to be infiltrated and penetrates into the opening defect portion, and then the excess permeate remaining on the surface of the object to be inspected without penetrating into the defect portion is removed. When using a dye penetrant, A thin layer of inorganic white powder (called “developer” among those skilled in the art) such as magnesium carbonate powder or calcium carbonate powder is formed on the surface of the object to be inspected, and penetrates into the opening defect portion by the thin layer. The defect-indicating bleed pattern appears by sucking out the dye penetrant liquid onto the surface of the thin layer, and is observed under natural light or white light. Is used, and without using the developer, the surface of the object to be inspected becomes yellowish green under the irradiation of an ultraviolet lamp (called “black light” by those skilled in the art) in a dark room. In this method, the presence / position of the opening defect portion is detected by a defect indicating fluorescent pattern that emits light (hereinafter, the flaw detection test employing this basic mode is referred to as a “well-known penetrant flaw detection test”).

  A wide variety of prescription products are commercially available and widely used for dyeing and fluorescent penetrants (hereinafter sometimes referred to as “penetrant”), which are used in well-known penetrant testing. The oil-soluble red dye (for example, Oil Red 5B: trade name: Orient Co., Ltd. or Sudan Red 462: trade name: BASF) or the oil-soluble fluorescent dye (for example, Fluorol 7GA: Product name: GAF: Fluorescent bright varnish agent 68: Product name: Nippon Kayaku Co., Ltd.) It can be classified into a water-based penetrant containing an organic solvent as a main solvent and an oil-based penetrant containing a flammable water-insoluble organic solvent (usually a high-boiling organic solvent) as a main solvent. The oil-based penetrant contains a diluent solvent (usually a volatile low / medium boiling organic solvent).

  And, among those skilled in the art, when removing a surplus permeate in a well-known permeation test, if a water-based permeate is used, the water-based permeate is removed by washing with water. If an oil-based penetrant does not contain a surfactant in the formulation, wipe it off with a cloth soaked with an organic solvent and remove it. Therefore, this oil-based permeate is called “solvent-removable oil-based permeate”, and the oil-based permeate contains a surfactant (usually a nonionic surfactant) in its formulation. This oil base permeate is called “water washable oil base permeate” because it is removed by washing with water.

  Representative commercial products for water-based water-based penetrants include Super Check P-LK (trade name: water and water-soluble organic solvents that are compatible with water, oil-soluble red dyes, surfactants, etc. Formulated liquid: Marktech Co., Ltd. and Super Glow OD-18S (Product name: Water and water-soluble organic solvents compatible with water are used as the main solvent, and oil-soluble fluorescent dyes, surfactants, etc. are included. Liquid: Marktech Co., Ltd.), and typical commercial products of solvent-removable oil-based penetrants include Super Check UP-ST (trade name: flammable water-insoluble organic solvent as the main solvent, Liquids containing oil-soluble red dyes, dilution solvents, etc .: Mark Tech Co., Ltd. are listed, and typical commercial products for washable oil-based penetrants include Super Check UP-G3 (trade name: flammable) Oil-soluble Liquids containing color dyes, surfactants, diluting solvents, etc .: Mark Tech Co., Ltd. and Eco Glow EG-2000 (trade name: Combustible water-insoluble organic solvents as main solvents, oil-soluble fluorescent dyes, interfaces A liquid in which an activator, a diluting solvent and the like are blended: Marktec Corporation).

  In addition to the above technical means, an oil-soluble red dye or an oil-soluble fluorescent dye is dissolved in a flammable water-insoluble organic solvent (an organic solvent that is not compatible with water), and an interface is formed. An oil-based penetrant that does not contain an activator is used to remove excess penetrant in well-known penetrant flaw detection tests by spraying water onto the surface of the test object at high water pressure (patented) Reference 1), a main solvent composed of 5 to 10% by weight of an oil-soluble red dye or oil-soluble fluorescent dye and a high-boiling organic solvent having a boiling point of 190 ° C. or higher that dissolves the dye, and a boiling point of 110 compatible with the main solvent. When a penetrating liquid containing 30 to 80% by weight of a diluting solvent composed of a volatile organic solvent at a temperature of 0 ° C. or lower is blended and permeated into an opening defect part in a well-known penetrant flaw detection test, 50 ~ 80% by weight of the permeate is evaporated There has been proposed a technical means for concentrating and detecting flaws in extremely fine openings (see Patent Document 2).

Japanese Patent Laid-Open No. 5-72148 JP-A-8-271448

  The prescription for the water-based water-based penetrant is that the main solvent is a mixture of water and a water-soluble organic solvent at a ratio that does not have a flash point. Since there is no problem with the amount of storage, it is widely used in automobile factories where large amounts of penetrants are used.

  However, when removing the excess permeate in the well-known penetrant testing, the main solvent of the water-based water-based permeate is water and a water-soluble organic solvent. In some cases, the penetrant solution is washed away (referred to as “overwashing” in the industry). In this case, the flaw detection accuracy is reduced, and the penetrating solution originally exhibits the performance. There is a problem of disappearing.

  Of course, when the solvent-removable oil-based permeate or the water-washable oil-based permeate is used, the main solvent is a water-insoluble organic solvent, so the overwash does not occur. Since the main solvent is a flammable, non-water-soluble organic solvent, it falls under the category of dangerous materials under the Fire Service Act, and there are problems with handling, storage amount, and safety of storage equipment.

  In view of the problems inherent in the water-washable water-based penetrant and the known penetrant flaw detection test using the penetrant, the present invention does not have a flash point and is used to remove the excess penetrant by washing. Occurrence of cleaning can be suppressed as much as possible, and the water-cleaning water-based penetrant for penetrant testing and having the same flaw detection performance as that of the above-mentioned commercially available water-based oil-based penetrant and penetrant flaw detection using the penetrant Providing a test method is a technical issue.

  In order to achieve the above technical problem, the present inventor has thought and error about the combination of water and various organic solvents as the main solvent for dissolving the oil-soluble red dye and oil-soluble fluorescent dye in the water-washable water-based penetrant. As a result of many trial manufactures and experiments, the organic solvent that dissolves the oil-soluble red dye and the oil-soluble fluorescent dye and water are dissolved in the water to form a single phase and the organic solvent. The solvent is separated from the water and is in a two-phase state. The two solvents are reversibly changed by temperature change and mixed at a ratio that does not have a flash point. A water-washable water-based penetrant is prepared by blending a solvent with an oil-soluble red dye or oil-soluble fluorescent dye and a surfactant, and using the penetrant, the permeate is removed when removing the surplus penetrant in a well-known penetrant test. Above the temperature at which the liquid separates into two phases If washed with water, the occurrence of the overwash can be suppressed as much as possible, and the remarkable technical knowledge that flaw detection can be performed with the same accuracy as the above-mentioned commercial product of the washable oil-based penetrant has been obtained. Achieved.

  The technical problem can be solved by the present invention as follows.

  That is, in the penetrant testing method according to the present invention, the organic solvent and water are dissolved in the water to form a single phase, and the organic solvent is separated from the water into two phases. An oil-soluble red dye or oil-soluble fluorescence that dissolves in the organic solvent and a main solvent obtained by reversibly changing between two phase states with the state of being in a reversible state with a change in temperature and having no flash point A water-based water-based penetrant for penetrant flaw detection, in which a dye and a surfactant are blended, is attached to the surface of the object to be inspected in a state where the phase of the penetrant is the single phase, and the penetrant After infiltrating the liquid into the opening defect portion of the surface of the object to be inspected, the surface of the object to be inspected is washed with warm water at a temperature equal to or higher than the temperature at which the phase state of the permeating liquid changes to the two phases and does not penetrate into the opening defect portion Remove excess permeate remaining on the surface of the test object, Is intended to flaw detection of the presence of the opening defect by permeate pervades portion (claim 1).

According to the penetrant flaw detection test method and the water-based water-based penetrant used in the penetrant flaw detection test method according to the present invention, the permeate contains a state in which the organic solvent is dissolved in water and is in a single phase. Since it has the property of reversibly changing between the two phase states with the two phases separated from the water by the temperature change, in removing the excess permeate in the penetration test, When washing with warm water above the temperature at which the permeate separates into two phases, the permeate penetrating into the opening defect part separates into two phases, and the separated upper phase part is an organic solvent component containing a small amount of water, Since it hardly dissolves in warm water, the occurrence of the overwash can be suppressed as much as possible, and the separated lower phase part contains water containing a small amount of an organic solvent component. Fluorescent) dye component moves to the upper phase Since the dye concentration in the upper phase is increased, a clear defect indication (brightness or fluorescence) pattern is obtained at the time of observation, with the same accuracy as when using the above-mentioned commercially available solvent-removable oil-based penetrant. Can detect flaws.

Moreover, since the water-based water-based penetrant used in the penetrant testing method according to the present invention does not have a flash point, it does not fall under the dangerous goods of the Fire Service Act, so there are no problems with handling, storage amount, and safety of storage facilities. .

  The embodiment of the present invention is as follows.

Embodiment 1 FIG.

The washable water-based penetrant used in the penetrant testing method according to the present embodiment includes diethylene glycol monoethyl ether acetate (hereinafter referred to as “EDGAC”), propylene glycol monomethyl ether acetate (hereinafter referred to as “PMA”), diethylene glycol diethyl ether ( A state in which one or two or more organic solvents selected from ethylene glycol monobutyl ether (hereinafter referred to as “BCL”) and water are dissolved in water to form a single phase. And the main solvent in which the organic solvent is separated from the water into a two-phase state and is mixed as much as possible with a change in temperature and does not have a flash point. An oil-soluble red dye or oil-soluble fluorescent dye that dissolves in the organic solvent and a surfactant are blended. That is a liquid material.

  The oil-soluble red dye, the oil-soluble fluorescent dye, and the blending ratio thereof may be those commonly used in known penetrant flaw detection penetrants. For the former, oil red 5B (trade name: Orient Co., Ltd.) Sudan Red 462 (trade name: BASF) is suitable, and Fluorol 7GA (trade name: GAF) and Fluorescent Bright Varnish Agent 68 (trade name: Nippon Kayaku Co., Ltd.) are suitable for the latter. In any of the dyes, 0.2 to 2% by weight is preferable, 1 to 2% by weight is more preferable, and if it is less than 0.2% by weight, a clear defect indication (brightening or fluorescent) pattern is observed during the observation. Therefore, the flaw detection accuracy is remarkably lowered. On the other hand, even if it exceeds 2% by weight, the flaw detection accuracy is not so improved.

  What is necessary is just to apply what is normally used for the penetration liquid for well-known penetrant flaw detection tests, and, as for the said surfactant and its mixture ratio, Nonionic surfactant, More specifically, the polyoxyalkylene of HLB value 8-13 Alkyl ethers such as Neugen NL-Dash408 (trade name: Daiichi Kogyo Co., Ltd.) are suitable, but it is also possible to reinforce the permeate using an ester surfactant such as polyoxyethylene fatty acid ester. The blending ratio is preferably 3 to 7% by weight when any surfactant is used, and if it is less than 3% by weight, sufficient penetrating power cannot be obtained, so that the flaw detection accuracy is remarkably lowered. Even if the weight percentage is exceeded, the flaw detection accuracy does not improve so much.

  The mixing ratio of water to the organic solvent in the main solvent is 1: 1 to 1: 2, and if the mixing ratio is within the range, each oil-soluble red dye described above or each oil-soluble fluorescent dye described above and each interface described above. An osmotic solution prepared by mixing and dissolving the active agent in a required proportion amount maintains the state of the single phase at room temperature (about 20 ° C.), and the osmotic solution is heated ( About 35 ° C. to 60 ° C.), it can be guaranteed that the two-phase state is changed and that the permeate has no flash point.

Preparation of a water-washable water-based penetrant used in the penetrant testing method according to the present embodiment is easy, and the main solvent 92 to 92 has a water mixing ratio of 1: 1 to 1: 2 with respect to the organic solvent. 96% by weight, each oil-soluble red dye described above or each oil-soluble fluorescent dye 1-2% by weight, each surfactant 3 to 7% by weight within each mixing ratio range so that the total amount is 100% by weight. Weigh the materials, put each weighed material into a stainless steel tank, and use an electric mixer etc. at room temperature (about 20 ° C) and stir until each material is mixed and dissolved into a single phase. do it.

  As long as the mixing ratio of water to the organic solvent is in the range of 1: 1 to 1: 2, a water-soluble organic solvent (for example, diethyl glycol monobutyl ether-hereinafter “ The effect of the present invention does not change even when-"BDG" is added within the range of 5 to 16% by weight. However, when BDG is added, the amount of the organic solvent must be reduced according to the amount added. (See Examples 4 and 5 below).

  Embodiment 2. FIG.

The penetrant testing method according to the present embodiment uses a water-washable water-based penetrant used in the penetrant flaw testing method according to the first embodiment, and the basic aspect thereof is the same as the well-known penetrant test. First, in the inspection working atmosphere at room temperature (about 20 ° C.), the water-washable water-based penetrating solution used in the penetrant testing method according to Embodiment 1 stored at the room temperature is applied to the surface of the object to be inspected. Then, it penetrates into the opening defect part (penetration treatment), and then the surface of the object to be inspected uses hot water of about 60 ° C. to 70 ° C., water pressure: about 0.3 to 0.5 MPa, flow rate: 1 to 3 L / min The excess permeate remaining on the surface of the object to be inspected without penetrating into the defective portion is washed and removed (cleaning process).

  When the surface of the object to be inspected after drying is dried, and the permeation liquid uses an oil-soluble red dye, a thin layer of the developer composed of the inorganic white powder is formed on the surface of the object to be inspected. The permeation liquid penetrating into the opening defect portion by the layer is sucked out to the surface of the thin layer so that a defect-indicating red rainbow pattern appears (development processing), and the surface of the object to be inspected is exposed to natural light or white light. This is a method of observing and detecting the presence / position of the opening defect portion by the bleed pattern.

  In addition, when the penetrating liquid uses an oil-soluble fluorescent dye, the object to be inspected after drying is dried and then subjected to ultraviolet light irradiation in a dark room without performing the development processing. This is a method in which the presence / position of an opening defect portion is detected by a defect indicating fluorescent pattern that emits yellowish green light by observing the surface.

  In the present embodiment, in the cleaning process, when the warm water is sprayed onto the surface of the inspection object with the water pressure and flow rate, the hot water that has contacted the inspection object surface at the beginning of cleaning is the temperature of the inspection object (usually, Since the object to be inspected is a metal member such as steel, its temperature is cooled to room temperature: about 20 ° C, much lower than that), and remains on the surface of the object to be inspected by the cooled water and its water pressure. As the excess permeate begins to be removed and cleaning proceeds, the temperature of the surface of the object to be inspected rises due to the hot water being sprayed and approaches the temperature of the hot water, and the permeate that has permeated into the opening defect is in two phases. Since the separated upper phase part is an organic solvent component containing a small amount of water, it hardly dissolves in the sprayed warm water, and the occurrence of the overwash is suppressed as much as possible. And the separated lower phase Is water containing a small amount of organic solvent component, so the oil-soluble (red or fluorescent) dye component dissolved in the penetrating liquid moves to the upper phase part and the dye concentration is higher in the upper phase part. In the case of a penetrating liquid using an oil-soluble red dye, a clear defect-indicating red blemishes pattern appears on the surface of the developer thin layer. In the case of a penetrating liquid using an oil-soluble fluorescent dye, an ultraviolet lamp in a dark room is used. The brightness of the yellow-green defect indicating fluorescent pattern that emits light under irradiation is high, and in any case, the defect indicating pattern can be easily determined at the time of observation, so that flaw detection can be performed with high accuracy.

  The present invention will be described in more detail with reference to examples and comparative examples. In addition, each of the separation temperature and flash point measurement of the penetrant and the penetrant flaw detection performance evaluation in each of the following examples and comparative examples were performed by the following methods.

  Measurement of separation temperature: Place the permeate to be measured in a glass beaker, gradually warm from room temperature (approx. 20 ° C), visually observe, and the temperature at which the permeate begins to clearly separate into two phases Was measured.

  Measurement of flash point: The flash point of the permeated liquid to be measured and the presence or absence of the flash point were measured according to JIS K 2265-4.

  Performance evaluation: Stainless steel test piece with 6mm length, 10μm width and 100μm depth (open defect) on the surface, 6mm length, 10μm width and 150μm depth on the surface (same as above) ) And a stainless steel test piece with a surface of 6 mm long, 10 μm wide and 200 μm deep (same as above), and at room temperature (about 20 ° C.) After applying the permeation liquid to be measured to the surface of each test piece and allowing it to stand for 5 minutes, the hot water of about 65 ° C. is sprayed on the surface of each test piece at a water pressure of 0.3 Mpa and a flow rate of 1 L / min, and washed. Next, after removing water droplets on the surface of the test piece by air blowing, each test piece is dried for 5 minutes with hot air at about 60 ° C. using a hot air circulation dryer, and then the permeation liquid to be evaluated is an oil-soluble red dye. On the surface of each test piece. A thin layer of inorganic white fine powder is formed using a developer for penetrating flaw detection (Super Check Developer UD-ST: Product Name: Main component is inorganic white fine powder: Marktech Co., Ltd.) and visually observed under white light When the permeated liquid to be evaluated is an oil-soluble fluorescent dye, it is visually observed under the irradiation of an ultraviolet lamp in a dark room without using a developer. The surface of each test piece was observed and evaluated.

  In the comparative example, the case where about 20 ° C. water was used instead of about 60 ° C. hot water was also evaluated.

  The evaluation standard is “○” when a clear defect indication pattern corresponding to the depth of the artificial flaw is visible (Note: If the penetrant is an oil-soluble red dye, the flaw is deep. If the defect indicating pattern is darker and larger in color, and the penetrant uses an oil-soluble fluorescent dye, the defect indicating pattern becomes brighter as the flaw is deeper). If the pattern is partly discontinuous, the color is light, or the brightness is low and the clarity is not clear, “△” indicates that the defect indicating pattern cannot be visually recognized (note: the defect indicating pattern does not appear). "

  Example 1: EDGAC 46.5 wt%, water 46.5 wt%, nonionic surfactant (Neugen NL-Dash408: trade name: HLB12: Daiichi Kogyo Co., Ltd.) 5.0 wt% and oil-soluble fluorescent dye (Fluorol7GA: trade name) : GAF) Weigh each material so that it becomes a prescription of 2.0% by weight, put each weighed material into a stainless steel tank, and stir for 30 minutes using an electric mixer at room temperature (about 20 ° C) Thus, a water-washable water-based fluorescent penetrating solution in which the respective materials were mixed and melted to form a single phase was prepared. The mixing ratio of water to EDGAC in the permeation solution is 1: 1.

  The separation temperature of the washable water-based fluorescent penetrating solution obtained here was 50 ° C., there was no flash point, and the flaw detection performance evaluation results were “◯” for all the test pieces.

  Example 2: Same as Example 1 except that 46.5% by weight of EDGAC was changed to 38.0% by weight of DEDG, 57.0% by weight of water, and 3.0% by weight of nonionic surfactant. Under the conditions, a washable water-based fluorescent permeation solution in which the respective materials were mixed and dissolved to form a single phase was prepared. In addition, the mixing ratio of water with respect to DEGD in the permeation solution is 1: 1.5.

  The separation temperature of the washable water-based fluorescent penetrant obtained here is 40 ° C., there is no flash point, and the flaw detection performance evaluation is “△” for a test piece having a scratch depth of 100 μm, and for other test pieces. It was “○”.

  Example 3: Example except that 3% by weight of EDGAC, 30.0% by weight of DEDG, 31.0% by weight of water, 7.0% by weight of nonionic surfactant (same as above), 1.0% by weight of oil-soluble fluorescent dye (same as above) A water-washable water-based fluorescent permeation solution in which the respective materials were mixed and dissolved in a single phase under the same conditions as in 1 was prepared. In addition, the mixing ratio of water with respect to EDGAC and DEDG in the permeation solution is 1: 1.96.

  The separation temperature of the washable water-based fluorescent penetrating solution obtained here was 37 ° C., there was no flash point, and the flaw detection performance evaluation results were “◯” for all the test pieces.

  Example 4: PMA 31.0% by weight, water 46.5% by weight, nonionic surfactant (same as above) 5.0% by weight, BDG 15.5% by weight and oil-soluble red dye (Oil Red 5B: trade name: Orient Corporation) 2.0 Each material is weighed so as to give a prescription of wt%, and each weighed material is put into a stainless steel tank and stirred at room temperature (about 20 ° C) for 30 minutes using an electric mixer. A washable water-based red penetrant in which the material was mixed and dissolved to form a single phase was prepared. The mixing ratio of water to PMA in the permeation solution is 1: 1.5.

  The separation temperature of the washable water-based red penetrant obtained here was 35 ° C., there was no flash point, and the flaw detection performance evaluation result was “◯” for any test piece.

  Example 5: Under the same conditions as in Example 4, except that PMA 31.0% by weight was changed to BCL 44.0% by weight, the water ratio was changed to 44.0% by weight, and the BOG ratio was changed to 5.0% by weight. A water-washable water-based red penetrant in which the respective materials were mixed and dissolved to form a single phase was prepared. The mixing ratio of water to BCL in the permeation solution is 1: 1.

  The separation temperature of the washable water-based red penetrant obtained here was 60 ° C., there was no flash point, and the flaw detection performance evaluation result was “◯” for any test piece.

  Example 6: PMA 31.0% by weight DEDG 31.0% by weight, water ratio 65.0% by weight, nonionic surfactant (same as above) ratio 3.0% by weight, oil-soluble red dye (same as above) A water-washable water-based red permeation in which each material is mixed and dissolved in a single phase under the same conditions as in Example 4 except that the ratio was changed to 1.0% by weight and BDG was not used. A liquid was prepared. In addition, the mixing ratio of water with respect to DEGG in the permeation solution is 1: 2.

  The separation temperature of the washable water-based red penetrant obtained here is 50 ° C., there is no flash point, and the flaw detection performance evaluation is “△” for a test piece with a scratch depth of 100 μm, and for other test pieces. It was “○”.

  Comparative Example 1: The ratio of EDGAC was changed to 18.0 wt%, the ratio of water to 78.0 wt%, the ratio of nonionic surfactant to 3.0 wt%, and the ratio of oil-soluble fluorescent dye to 1.0 wt%, respectively. Except for the above, under the same conditions as in Example 1, a comparative washable water-based fluorescent permeation solution in which the respective materials were mixed and dissolved to form a single phase was prepared. The mixing ratio of water to EDGAC in the permeation solution is 1: 4.3.

  The comparative washable water-based fluorescent penetrant obtained here does not separate into two phases even when the liquid temperature is raised to 100 ° C, there is no flash point, and the flaw detection performance evaluation result is about 20 ° C water. When used, it is “×” for a specimen having a flaw depth of 100 μm, “△” for a specimen having a flaw depth of 150 μm, and “◯” for a specimen having a flaw depth of 200 μm. When hot water was used, the test piece with a scratch depth of 100 μm and the test piece with a depth of 150 μm were both “x”, and the test piece with a crack depth of 200 μm was “Δ”.

  Comparative Example 2: PMA 31.0% by weight EDGAC 39.2% by weight, water ratio 58.8% by weight, respectively, except that surfactant and BDG were not used, under the same conditions as Example 4 A comparative washable water-based red penetrant in which each material was mixed and dissolved to form a single phase was prepared. In addition, the mixing ratio of water with respect to EDGAC of the said permeate is 1: 1.5.

  The separation temperature of the comparative washable water-based red penetrant obtained here is 43 ° C, there is no flash point, and the flaw detection performance evaluation result is a flaw depth of 100μm when using water at about 20 ° C. “×” for the test piece, “△” for both the test piece with a depth of 150 μm and the test piece with a depth of 200 μm, and when the hot water of about 65 ° C. is used, the depth is 100 μm. The test piece was “x”, the test piece having a flaw depth of 150 μm was “Δ”, and the test piece having a flaw depth of 200 μm was “◯”.

  Comparative Example 3 Example 1 except that 46.5% by weight of water, 5.0% by weight of a nonionic surfactant (same as above), 46.5% by weight of BDG and 2% by weight of an oil-soluble fluorescent dye (same as above) were used, and EDGA was not used. A comparative washable water-based fluorescent permeation solution in which each material was mixed and dissolved in a single phase under the same conditions was prepared.

  The comparative washable water-based fluorescent penetrant obtained here does not separate into two phases even when the liquid temperature is raised to 100 ° C, there is no flash point, and the flaw detection performance evaluation results use water of about 20 ° C In this case, the test piece with a scratch depth of 100 μm and the test piece with a depth of 150 μm are both “△”, and the test piece with a crack depth of 200 μm is “◯”, using hot water of about 65 ° C. In this case, the test piece having a scratch depth of 100 μm was “×”, the test piece having a scratch depth of 150 μm was “Δ”, and the test piece having a scratch depth of 200 μm was “◯”.

  Comparative Example 4: EDGAC 46.5% by weight, water-insoluble organic solvent (Cactus normal paraffin N-12: trade name: normal paraffin: Japan Energy Co., Ltd.) 40.0% by weight, nonionic surfactant (same as above) 5.0% by weight, BDG 6.5% by weight, oil-soluble fluorescent dye (same as above) 2.0% by weight, except that water was not used, each material was mixed and dissolved in a single phase under the same conditions as in Example 1. A comparative washable oil-based fluorescent penetrant was prepared.

  The comparative washable oil-based fluorescent penetrant obtained here does not separate into two phases even when the liquid temperature is raised to 100 ° C, the flash point is 89 ° C, and the flaw detection performance evaluation result is about 20 ° C. In the case of using water of approximately 65 ° C and in the case of using hot water of about 65 ° C, △ is indicated for specimens with a scratch depth of 100 μm, and specimens with a depth of 150 μm and specimens with a depth of 200 μm are both used. It was “○”.

  According to the present invention, a well-known penetrant flaw detection test can be performed using a flushable water-based penetrant having no flash point, and the occurrence of overwashing is suppressed as much as possible in removing the surplus penetrant so that the test can be performed with high accuracy. Since fine opening defects on the surface of the inspection object can be inspected, it can meet the demands of the penetration inspection field in automobile factories that require large-scale use / storage of penetrant and high-accuracy defect detection performance. Therefore, it can be said that the present invention has great industrial applicability.

Claims (1)

An organic solvent and water are dissolved in the water to form a single phase, and the organic solvent is separated from the water into a two-phase state. Penetration in which a main solvent mixed reversibly with a temperature change and having a flash point and an oil-soluble red dye or oil-soluble fluorescent dye dissolved in the organic solvent and a surfactant are blended A washable water-based penetrant for flaw detection tests is attached to the surface of the inspection object in a state in which the phase of the permeation liquid is the single phase, and the permeation liquid penetrates into an opening defect portion on the surface of the inspection object. Then, excess permeation that remains on the surface of the inspection object without being infiltrated into the opening defect by washing the surface of the inspection object with warm water at a temperature equal to or higher than the temperature at which the phase state of the permeation liquid changes to the two phases. Remove the liquid and then open it with the permeate that has penetrated into the opening defect Penetrant method characterized by testing for the presence of Recessed portion.