JP5720944B2 - Penetration testing method using washable water based penetrant for penetration testing - Google Patents

Description

  The present invention relates to a water-based water-based penetrant for penetrant testing applied to flaw detection of fine opening defects existing on the surface of various members such as automobile members and a penetrant flaw testing method using the penetrant. .

  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. Commercially available products commonly used by those skilled in the art include oil-soluble red dyes (for example, Oil Red 5B: trade name: Orient Corporation and Sudan Red 462: trade name: BASF) or oil-soluble fluorescent dyes (for example, Fluorol 7GA: Product name: GAF company: 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.

  Typical commercially available water-based water-based penetrants include Super Check P-LK (trade name: water and water-soluble organic solvents that are compatible with water as main solvents, oil-soluble red dyes, surfactants, etc. Liquid blended: Marktech Co., Ltd. and Super Glow OD-18S (trade name: water and water-soluble organic solvent compatible with water as the main solvent, oil-soluble fluorescent dye, surfactant, etc. are blended A typical commercial product of solvent-removable oil-based penetrant is Super Check UP-ST (trade name: flammable water-insoluble organic solvent as the main solvent, Liquids containing oil-soluble red dyes, diluent solvents, etc .: Marktech Co., Ltd. are listed. Typical commercial products for water-washable oil-based penetrants include Super Check UP-G3 (trade name: flammable) Water-insoluble Liquids containing oil-soluble red dyes, surfactants, diluents, etc., with solvent as the main solvent: Marktech Co., Ltd. and Eco Glow EG-2000 (trade name: flammable water-insoluble organic solvents) And a liquid in which an oil-soluble fluorescent dye, a surfactant, a diluting solvent and the like are blended: Marktec Corporation).

  Flushable water-based penetrants contain water and water-soluble organic solvents in a proportion that does not have a flash point, and meet the standards of the Fire Service Law, so there are no problems in handling and storage. It is widely used in automobile factories where large amounts of penetrant are used.

  Solvent-removable oil-based penetrants and water-washable oil-based penetrants generally do not remove the penetrant that has penetrated into the opening defect as compared to water-washable water-based penetrants. The flaw detection accuracy is higher than that of the water-based penetrant, and it is used to detect fine opening defects.

  The present inventors reversibly change the two phase states of a state in which the organic solvent and water are dissolved into a single phase and a state in which the organic solvent is separated from water into two phases by temperature change. Flushable water-based penetrant that changes to, does not have a flash point, meets the standards of the Fire Service Act, so there is no problem in handling and storage, and excessive penetrant that has penetrated into the opening defect part Since it is not removed, a water-washable water-based penetrant having high flaw detection accuracy equivalent to the water-washable oil-based penetrant has been successfully developed (Patent Document 1).

  Further, in the known penetrant flaw detection test, a method of selectively detecting an opening defect portion having a depth to be detected by changing the flaw detection accuracy by properly using the various penetrants and cleaning methods has been attempted.

JP 2008-275335 A

  In the removal of surplus permeate in the well-known permeation test, the water-based water-based permeate is a water-soluble organic solvent. The liquid may be washed away (hereinafter referred to as “overcleaning”), and in this case, the flaw detection accuracy is lowered, and thus there is a possibility that a fine opening defect portion may not be detected.

  The solvent-removable oil-based penetrant or the water-washable oil-based penetrant does not cause the overcleaning because the main solvent is a water-insoluble organic solvent, but it falls under the Fire Service Act and is handled and stored. There are problems with quantity and safety of storage facilities.

  In addition, since neither oil-based penetrant is overwashed, the flaw detection accuracy is high, and even fine opening defects can be detected. There is a problem that a defect indicating bleed pattern or a defect indicating fluorescent pattern (hereinafter referred to as “defect indicating pattern” together with a defect indicating bleed pattern and a defect indicating fluorescent pattern) indicating a fine opening defect portion having an outer depth increases.

  The water-washable water-based penetrant described in Patent Document 1 has no flash point, does not have a problem in handling and storage, and has the same detection accuracy as the water-washable oil-based penetrant. Similar to the penetrating liquid, when the opening defect portion to be detected is deep to some extent, there is a problem that the defect indication pattern outside the detection target increases.

  Furthermore, the water washing in which the organic solvent and water are dissolved to form a single phase and the organic solvent is separated from the water and separated into two phases are reversibly changed by temperature change. Because it is a water-based penetrant, if it is washed with warm water at or above the temperature at which it separates into two phases, it will immediately change to two phases regardless of the temperature and maintain high flaw detection accuracy. The flaw detection accuracy cannot be changed.

  Therefore, when changing the detection accuracy, it is necessary to change the penetrant depending on the depth of the opening defect to be detected. However, at the penetrant testing site, the penetrant used is removed from the penetrant tank and penetrated. After washing the liquid tank, it is necessary to put in the permeate with the required detection accuracy, which is very laborious.

  In addition, in order to selectively detect the opening defect portion having a depth to be detected by the cleaning method, it penetrates into a minute opening defect having a depth less than the depth of the opening defect portion to be detected. It is necessary to wash away the permeated liquid, and there are means for increasing the jetting pressure of water during washing or lengthening the washing time. However, if the injection pressure is increased or the cleaning time is lengthened, the amount of cleaning water to be used increases, so the amount of drainage also increases. Since the wastewater contains excess permeate, the wastewater becomes industrial waste. Therefore, the amount of drainage should be as small as possible.

  The present inventor has made it a technical subject to solve the above-mentioned problems, and as a result of many trial and error trial manufactures and experiments, the surfactant in the water-soluble water-based penetrant is changed to an interface having a cloud point. By using an activator, between the two phase states of the surfactant being dissolved in water and becoming a single phase, and the surfactant being separated from water and being in a two-phase state Is mixed in a ratio that reversibly changes with temperature, and is used as a main solvent, and an oil-soluble red dye or an oil-soluble fluorescent dye is blended in the main solvent to prepare a water-washable water-based penetrant, When washing and removing surplus permeate in well-known penetrant flaw detection tests with warm water, use warm water at a temperature equal to or higher than the temperature at which the permeate separates into two phases (hereinafter referred to as “separation temperature”). If the temperature difference from the temperature is small, deep opening defects Flaw detection accuracy can be changed by the temperature difference between the separation temperature and the temperature of the hot water used for cleaning, in which, if the temperature difference is large, even fine opening defects can be detected. The above-mentioned technical problem has been achieved by obtaining the remarkable knowledge.

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

That is, in the present invention, a surfactant having a cloud point and water are dissolved in water to form a single phase, and the surfactant is separated from water into two phases. A main solvent formed by reversibly changing between two phase states with a change in temperature and an oil-soluble red dye or oil-soluble fluorescent dye dissolved in the main solvent, and the surfactant is 10 to 30% by weight, 40 to 80% by weight of the water, and 0.2 to 2% by weight of the oil-soluble dye, and a water-based penetrant having no flash point, and the permeate change in state from a state which is the single phase has become the two phases are arising at a temperature above the cloud point of the water-based penetrant, in the phase state is the single phase In this state, the permeate is attached to the surface of the inspection object and the opening defect on the surface of the inspection object The surface of the object to be inspected is washed with warm water having a temperature equal to or higher than the cloud point of the permeation solution after permeating into the permeation solution to remove the remaining permeate remaining without permeating into the opening defect portion and in the opening defect portion. In the penetrant flaw detection test method, the phase state of the penetrating liquid penetrating into the two-phase state is changed, and then the presence of the opening defect portion is detected by the penetrating liquid penetrating the opening defect portion. An opening defect portion having a depth to be detected by adjusting a temperature difference between the cloud point of the penetrating liquid and the temperature of the hot water used for the cleaning according to the depth of the opening defect portion to be detected. This is a penetrant testing method characterized in that the presence of water is detected (claim 1).

Further, in the present invention, the surfactant having a cloud point of the penetrant is selected from polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether and polyoxyethylene alkylamine. The penetrant flaw detection test method according to claim 1, wherein there are one or more kinds (claim 2).

Further, the present invention includes a feature that has been incorporated the diethylene glycol monobutyl ether in the permeate, one selected from butyl glycol and methyl dipropylene glycol or 2 or more kinds at a rate of 5% to 35% by weight The penetration flaw detection test method according to claim 1 or 2 (claim 3).

Moreover, this invention is a temperature by which the temperature of the cloud point of the said osmosis | permeation liquid is selected from the range of 40 to 70 degreeC, The penetration test method in any one of the Claims 1 thru | or 3 characterized by the above-mentioned. (Claim 4 ).

The “separation temperature” in the present specification refers to a temperature at which the phase state of the water-washable water-based permeate according to the present invention is separated from a single phase into two phases.
In addition, the “cloud point” in the present specification refers to the temperature at which the surfactant becomes transparent or translucent at low temperatures but becomes opaque when heated, and relates to the present invention. The “separation temperature” is referred to for the water-based water-based penetrant.

  According to the washable water-based penetrant for penetrant testing according to the present invention and the penetrant flaw testing method using the penetrant, the penetrant is in a single phase with the surfactant dissolved in water and Since the surfactant has the property of reversibly changing between the two phases of the state separated from water and in a two-phase state due to a temperature change, If washing is performed using warm water that is at or above the separation temperature and has a large temperature difference with the separation temperature, the permeate that has permeated into the opening defect portion is quickly separated into two phases, and the separated upper phase portion contains a small amount of water. Since it is a surfactant component contained, it hardly dissolves in warm water, so that the occurrence of overcleaning can be suppressed as much as possible, and even fine opening defect portions can be detected.

  In addition, if washing is performed using warm water that is equal to or higher than the separation temperature of the permeation liquid and has a small temperature difference from the separation temperature, it takes time for the permeation liquid penetrating into the opening defect to separate into two phases. In addition to the excess permeate, the permeate that has penetrated into the fine opening defect is also washed away, but the permeate that has penetrated into the deep opening defect takes time to be washed away and reaches the separation temperature without being washed away. Since no further cleaning is performed, deep opening defects can be selectively detected.

  Moreover, since the flaw detection accuracy can be changed by changing the temperature difference between the separation temperature of the permeation liquid and the temperature of the washing water, an opening defect portion having a depth to be detected by the same permeation liquid and the same flaw detection apparatus. Can be selectively detected, so that the work efficiency is greatly improved.

  Furthermore, by changing only the temperature of warm water used for washing, a temperature difference can be provided between the temperature of separation of the permeate and the temperature of warm water used for washing. Only the temperature of the hot water to be used is changed, the excess permeate is washed and removed, and the permeate penetrating into the opening defect of the depth to be detected is selectively left to open the depth of the target to be detected. A defective portion can be selectively detected. As a result, there is no need to change the cleaning method such as increasing the injection pressure or lengthening the cleaning time, so that the amount of cleaning water is constant and an increase in the amount of drainage can be prevented.

  Moreover, since surfactants with various cloud points are commercially available, the cloud point (separation temperature) of the permeate can be selected by selecting and blending the required surfactants. ), Penetrants with different detection accuracy depending on the combination with the temperature can be easily and inexpensively prepared.

  In other words, the detection accuracy can be changed without taking the trouble of changing the penetrant for penetrant testing or changing the cleaning method to increase the amount of drainage. An opening defect portion having a depth to be inspected according to the strength or the like can be selectively detected with the same permeation solution and the same flaw detection apparatus.

  In addition, since the separated lower phase part is water containing a small amount of a surfactant, the dissolved oil-soluble (red or fluorescent) dye component moves to the upper phase part and the dye concentration in the upper phase part becomes high. Since a clear defect indication pattern is formed, detection accuracy equivalent to that of a conventional oil-based penetrant can be obtained.

  In addition, since the penetrant does not have a flash point, it does not fall under the category of dangerous materials under the Fire Service Law, and therefore there are no problems with handling, storage amount, and safety of storage facilities.

  The embodiment of the present invention is as follows.

  The washable water-based penetrant for penetrant testing according to the present embodiment is selected from polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, and polyoxyethylene alkylamine 1 Alternatively, a surfactant having two or more cloud points and water are dissolved in the water to form a single phase, and the surfactant is separated from the water into two phases. An oil-soluble red dye or oil-soluble fluorescent dye that dissolves in the main solvent is blended in the main solvent that is mixed so that the two phase states of the two phases change reversibly with temperature. It is a liquid material.

(Manufacture of washable water-based penetrant for penetration testing)
The surfactant is a nonionic surfactant having a cloud point and has an HLB value of 9-14.

  The blending ratio is 10% by weight to 30% by weight. If it is less than 10% by weight, the surfactant phase in the upper phase part becomes thin when separated into two phases, and over-cleaning may not be prevented and the flaw detection accuracy may be lowered. This is because the viscosity increases, the permeability to the opening defect portion decreases, and the flaw detection accuracy may decrease.

  What is necessary is just to select and mix | blend the said surfactant with the required cloud point from a commercial item, and as polyoxyethylene polyoxypropylene alkyl ether, for example, Neugen NL-Dash410 (HLB: 12.5, cloud point measurement, cloud point) : 66 ° C (1% aqueous solution), manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Neugen SD-70 (HLB: 13.2, cloud point measurement / clouding point: 64 ° C (1% aqueous solution), Daiichi Kogyo Seiyaku Co., Ltd. Manufactured), Neugen XL-70 (HLB: 13.2, cloud point measurement / clouding point: 40 ° C. (1% aqueous solution), manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Neugen XL-80 (HLB: 13.8, cloudy) Point measurement / cloud point: 55 ° C. (1% aqueous solution), manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neugen XL-40 (HLB: 10.5, cloud point measurement / cloud point: 53 ° C. (10% aqueous solution, 10% aqueous solution contains 25% BDG) Manufactured by Kogyo Seiyaku Co., Ltd., Neugen LF-30X (HLB: 9.4, cloud point measurement, cloud point: 42 ° C. (10% aqueous solution, including 25% BDG in 10% aqueous solution), Daiichi Kogyo Seiyaku Co., Ltd. Company), Neugen TDX-80D (HLB: 13.1, cloud point measurement / cloud point: 56 ° C. (1% aqueous solution), manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), polyoxyethylene alkyl ether is Neugen DKS NL- 60 (HLB: 11.5, cloud point measurement / cloud point: 43 ° C. (1% aqueous solution), manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) is used as polyoxyethylene alkylphenyl ether, Blaunon N-509 (HLB: 12.2. 8. Cloud point measurement / cloud point: 48 ° C. (1% aqueous solution), manufactured by Aoki Yushi Kogyo Co., Ltd.) As polyoxyethylene alkylamine, Brownon L-205 (HLB: 10.4, cloud point measurement / cloud point: 59 ° C. (1% aqueous solution) manufactured by Aoki Oil & Fat Co., Ltd. can be used.

  The oil-soluble red dye, the oil-soluble fluorescent dye, and the blending ratio thereof may be those commonly used in penetrants for known penetrant flaw detection tests. 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. Is 0.2 to 2% by weight when any dye is used. If the amount is less than 0.2% by weight, a clear defect indication pattern cannot be obtained at the time of observation, so that the flaw detection accuracy is remarkably lowered. On the other hand, if the amount exceeds 2% by weight, a clearer defect indication pattern is obtained. This is because the flaw detection accuracy is not improved so much.

  The amount of water is 40% to 80% by weight. If it is within the range of the blending ratio, the penetrating liquid in which the surfactant and the respective oil-soluble red dyes or the respective oil-soluble fluorescent dyes are blended and dissolved in the required ratio amounts to room temperature (about 20 ° C.). Is maintained in the single phase, and can be guaranteed to change to the two-phase state when the permeate is heated to a temperature equal to or higher than the cloud point temperature.

  If necessary, one or more selected from the group consisting of diethylene glycol monobutyl ether (BDG), butyl glycol (BG), and methyldipropylene glycol (DPGM), which is a water-soluble organic solvent, is used as the main solvent in an amount of 5% by weight to 5% by weight. By adding 35% by weight, the separation temperature of the permeate can be adjusted.

(Preparation of washable water-based penetrant)
Preparation of a washable water-based penetrant for penetrant testing according to the present embodiment is easy, with 10% to 30% by weight of the surfactant, 40% to 80% by weight of the water, and each oil Each material is weighed so that the total amount of the soluble red dye or each oil-soluble fluorescent dye is 0.2 to 2% by weight within each blending ratio range, and the weighed material is placed in a stainless steel tank. The mixture may be added and stirred at room temperature (about 20 ° C.) using an electric mixer or the like until each material is mixed and dissolved to form a single phase.

  In order to finely adjust the temperature at which the penetrant changes from a single phase state to a two phase state, the water-soluble organic solvent is added within a range of 5 wt% to 35 wt% as necessary. In this case, however, it is necessary to reduce the amount of water according to the amount added.

  If the cloud point (separation temperature) of the penetrating liquid is selected from the range of 40 ° C. to 70 ° C., the penetrating liquid having the required flaw detection accuracy can be easily prepared.

(Penetration testing method)
The penetration flaw detection test method according to the present embodiment first inspects the water-based water penetration penetrant for penetration flaw testing according to the present invention stored at the room temperature in an inspection working atmosphere at room temperature (about 20 ° C.). It is applied and adhered to the surface of the object, and penetrates into the opening defect part (penetration treatment). Then, the surface of the object to be inspected is used with hot water of about 50 ° C. to 80 ° C., and the water pressure is about 0.3 to 0.5 Mpa. -Flow rate: The excess permeate remaining on the surface of the object to be inspected without being permeated into the defective portion at 1 to 3 L / min is washed and removed (cleaning process).

  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 the inspection object is steel, etc. Therefore, the excess permeated liquid remaining on the surface of the object to be inspected by the cooled water and its water pressure is cooled down to room temperature: about 20 ° C.). As the cleaning starts, 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 penetrating into the opening defect part is separated into two phases and separated. The upper phase part is a surfactant containing a small amount of water, and since the surfactant is saturated with water, it hardly dissolves in the sprayed warm water. Can be suppressed, or Since the separated lower phase is water containing a small amount of surfactant, the oil-soluble (red or fluorescent) dye component dissolved in the permeation solution moves to the upper phase and the dye concentration in the upper phase In the case of a penetrating liquid using an oil-soluble red dye, a clear defect-indicating red blurring pattern appears on the surface of the developer thin layer, and in the case of a penetrating liquid using an oil-soluble fluorescent dye, Since the brightness of the yellow-green defect indicating fluorescent pattern that emits light under the irradiation of the ultraviolet lamp in the dark room is high, and in any case, the defect indicating pattern can be easily determined at the time of observation, so that the flaw can be detected with high accuracy.

  At this time, when the temperature of the warm water for washing is equal to or higher than the separation temperature of the washable water-based permeation solution of the present invention and the temperature difference between the separation temperature and the warm water is large, it is quickly separated into a two-phase state, Since the upper phase that is in contact with warm water is a surfactant saturated with water, it prevents over-cleaning and increases the detection accuracy. Therefore, even a fine opening defect having a depth of about 100 μm is detected. be able to.

  On the other hand, when the temperature of the hot water is equal to or higher than the separation temperature of the washable water-based permeation liquid of the present invention and the temperature difference between the separation temperature and the hot water is small, it takes time to separate into a two-phase state, In the meantime, along with the excess permeate, the permeate that has penetrated into the fine opening defect part is also washed away, but the permeate that has penetrated into the deep opening defect part reaches the separation temperature without being washed away and can be washed further. Therefore, the permeation liquid remains in the deep opening defect portion, and the opening defect portion can be detected.

When the temperature difference between the separation temperature of the washable water-based penetrant according to the present invention and the hot water used for washing is less than 10 ° C., it is possible to detect a large opening defect having a depth of 200 μm or more. it can.
When the temperature difference is 10 ° C. to 20 ° C., it is possible to detect an opening defect having an opening defect depth of 150 μm or more.
When the temperature difference is 20 ° C. or more, it is possible to detect a fine opening defect having an opening defect depth of about 100 μm.

  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 detected in a glass beaker and observe it visually while gradually warming it from room temperature (about 20 ° C.). The temperature 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: Using a stainless steel test piece having a surface of 6 mm, a width of 20 μm, and a depth of 100 μm, 150 μm, and 200 μm of artificial scratches (opening defect), at room temperature (about 20 ° C.), After applying and penetrating the permeation liquid to be measured to the surface of the test piece and allowing it to stand for 5 minutes, the cleaning water at each temperature is sprayed onto the surface of the test piece at a water pressure of 0.3 MPa and a flow rate of 1 L / min. Then, after removing water droplets on the surface of the test piece by air blow, the test piece is dried with hot air at about 70 ° C. for 5 minutes using a hot air circulation dryer, and the permeation liquid to be detected is an oil-soluble red dye. If it is used, an inorganic white using a commercially available developer for dye penetration testing (super check developer: trade name: inorganic white fine powder: Marktech Co., Ltd.) on the surface of each test piece. A thin layer of powder is formed, and the surface of the thin layer is visually observed under white light for evaluation. When the permeation liquid to be evaluated is an oil-soluble fluorescent dye, a developer is used. Without using, the surface of each test piece was visually evaluated under the irradiation of an ultraviolet irradiation lamp in a dark room.

  The evaluation standard is “○” when a clear defect indication pattern corresponding to the depth of the artificial scratch is visible (Note: If the penetrant is an oil-soluble red dye, the scratch is deep. If the defect indication pattern is darker and larger in color, and the penetrant uses an oil-soluble fluorescent dye, the defect indication pattern brightness increases as the scratch becomes 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). "

  Moreover, the amount of washing water (drainage amount) used for the washing treatment was 0.58 L.

Example 1
Nonionic surfactant (trade name: Neugen NL-Dash410 (HLB: 12.5, cloud point measurement / cloud point: 66 ° C. (1% aqueous solution)), Daiichi Kogyo Seiyaku Co., Ltd.) 25% by weight, oil-soluble Fluorescent dye (trade name: Fluoro 17GA, GAF) 1.0% by weight, each material was weighed so that the formulation was 74% by weight, and each weighed material was put into a stainless steel tank at room temperature (about At 20 ° C., a water-washable water-based fluorescent permeation solution in which the respective materials were mixed and dissolved to form a single phase was prepared by stirring for 30 minutes using an electric mixer.

The cloudable point (separation temperature) of the washable water-based fluorescent penetrant obtained here was 66 ° C., and there was no flash point.
The flaw detection performance evaluation at a cleaning water temperature of 70 ° C. was “x” at a scratch depth of 100 μm, “Δ” at a scratch depth of 150 μm, and “◯” at a scratch depth of 200 μm.

(Example 2)
Nonionic surfactant 1 (trade name: Neugen TDX-80D (HLB: 13.1, cloud point measurement / cloud point: 56 ° C. (1% aqueous solution)), Daiichi Kogyo Seiyaku Co., Ltd.) 10% by weight, nonion Surfactant 2 (trade name: Neugen XL-80 (HLB: 13.8, cloud point measurement / cloud point: 55 ° C. (1% aqueous solution)), Daiichi Kogyo Seiyaku Co., Ltd.) 15% by weight, oil-soluble Each material was weighed so that a fluorescent dye (trade name: Fluoro17GA, GAF) 1.0 wt% and water 74 wt% was formulated, and the materials were mixed and dissolved under the same conditions as in Example 1. Thus, a washable water-based fluorescent permeation solution in a single phase state was prepared.

The cloudable point (separation temperature) of the washable water-based fluorescent penetrant obtained here was 55 ° C., and there was no flash point.
The flaw detection performance evaluation at a cleaning water temperature of 70 ° C. was “Δ” at a scratch depth of 100 μm, “◯” at a scratch depth of 150 μm, and “◯” at a scratch depth of 200 μm.

(Example 3)
Nonionic surfactant (trade name: Neugen DKS NL-60 (HLB: 11.5, cloud point measurement / cloud point: 43 ° C. (1% aqueous solution)), Daiichi Kogyo Seiyaku Co., Ltd.) 25% by weight, oil Soluble fluorescent dye (trade name: Fluoro 17GA, GAF) 1.0% by weight and each material were weighed so that the formulation was 74% by weight of water. A water-washable water-based fluorescent penetrating solution that was dissolved to form a single phase was prepared.

The cloudable point (separation temperature) of the washable water-based fluorescent penetrant obtained here was 43 ° C. and there was no flash point.
The flaw detection performance evaluation at a cleaning water temperature of 70 ° C. was “◯” at a scratch depth of 100 μm, “O” at a scratch depth of 150 μm, and “O” at a scratch depth of 200 μm.

Example 4
Nonionic surfactant (trade name: Neugen XL-70 (HLB: 13.2, cloud point measurement / cloud point: 40 ° C. (1% aqueous solution)), Daiichi Kogyo Seiyaku Co., Ltd.) 20% by weight, oil-soluble Each material was weighed so that a red dye (trade name: Oil Red 5B, manufactured by Orient Co., Ltd.) 2.0% by weight, DPGM 10% by weight, water 68% by weight, and under the same conditions as in Example 1, A water-washable water-based red penetrant in which the respective materials were mixed and dissolved to form a single phase was prepared.

The cloudable point (separation temperature) of the washable water-based red penetrant obtained here was 65 ° C., and there was no flash point.
The flaw detection performance evaluation at a cleaning water temperature of 70 ° C. was “x” at a scratch depth of 100 μm, “Δ” at a scratch depth of 150 μm, and “◯” at a scratch depth of 200 μm.

(Example 5)
Nonionic surfactant (trade name: Neugen XL-40 (HLB: 10.5, cloud point measurement / cloud point: 53 ° C. (10% aqueous solution, including 25% BDG in 10% aqueous solution)), first Kogyo Seiyaku Co., Ltd.) 10% by weight, oil-soluble red dye (trade name: Oil Red 5B manufactured by Orient Co., Ltd.) 2.0% by weight, BDG 25% by weight, water 63% by weight. Then, under the same conditions as in Example 1, a washable water-based red penetrant in which the respective materials were mixed and dissolved to form a single phase was prepared.

The cloudable point (separation temperature) of the washable water-based red penetrant obtained here was 53 ° C., and there was no flash point.
The flaw detection performance evaluation at a cleaning water temperature of 70 ° C. was “Δ” at a scratch depth of 100 μm, “◯” at a scratch depth of 150 μm, and “◯” at a scratch depth of 200 μm.

(Example 6)
Nonionic surfactant (trade name: Neugen XL-70 (HLB: 13.2, cloud point measurement / cloud point: 40 ° C. (1% aqueous solution)), Daiichi Kogyo Seiyaku Co., Ltd.) 15% by weight, oil-soluble Each material was weighed so that a red dye (trade name: Oil Red 5B, manufactured by Orient Co., Ltd.) 2.0% by weight, BG 15% by weight, and water 68% by weight was prepared. A water-washable water-based red penetrant in which the respective materials were mixed and dissolved to form a single phase was prepared.

The cloudable point (separation temperature) of the washable water-based red penetrant obtained here was 46 ° C. and there was no flash point.
The flaw detection performance evaluation at a cleaning water temperature of 70 ° C. was “◯” at a scratch depth of 100 μm, “O” at a scratch depth of 150 μm, and “O” at a scratch depth of 200 μm.

(Example 7)
Nonionic surfactant (trade name: Neugen LF-30X (HLB: 9.4, cloud point measurement / cloud point: 42 ° C. (10% aqueous solution, including 25% BDG in 10% aqueous solution)), first Kogyo Seiyaku Co., Ltd.) 10% by weight, oil-soluble fluorescent dye (trade name: Fluoro 17GA, GAF) 1.0% by weight, BDG 25% by weight, water 64% by weight. Under the same conditions as in Example 1, a water-washable water-based fluorescent permeation solution in which the respective materials were mixed and dissolved to form a single phase was prepared.

The cloudable point (separation temperature) of the washable water-based fluorescent penetrant obtained here was 42 ° C. and there was no flash point.
The flaw detection performance evaluation at a cleaning water temperature of 20 ° C. was “x” at a scratch depth of 100 μm, “x” at a scratch depth of 150 μm, and “Δ” at a scratch depth of 200 μm (reference example).
The flaw detection performance evaluation at a cleaning water temperature of 50 ° C. was “x” at a scratch depth of 100 μm, “Δ” at a scratch depth of 150 μm, and “◯” at a scratch depth of 200 μm.
The flaw detection performance evaluation at a cleaning water temperature of 60 ° C. was “Δ” at a scratch depth of 100 μm, “◯” at a scratch depth of 150 μm, and “◯” at a scratch depth of 200 μm.
The flaw detection performance evaluation at a cleaning water temperature of 70 ° C. was “◯” at a scratch depth of 100 μm, “O” at a scratch depth of 150 μm, and “O” at a scratch depth of 200 μm.

(Comparative Example 1)
25% by weight of polyoxyethylene tridecyl ether (trade name: Neugen TDS-200D (HLB: 16.3, cloud point measurement / cloud point: 80 ° C. or higher (1% aqueous solution)), manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) Oil-soluble red dye (trade name: Oil Red 5B manufactured by Orient Co., Ltd.) 1.0% by weight, each material was weighed so as to have a prescription of 74% by weight of water. A washable water-based red penetrant in which the material was mixed and dissolved to form a single phase was prepared.

The cloudable point (separation temperature) of the washable water-based red penetrant obtained here was 80 ° C. or higher, and there was no flash point.
The evaluation of flaw detection performance at a cleaning water temperature of 70 ° C. was “x” at a scratch depth of 100 μm, “x” at a scratch depth of 150 μm, and “x” at a scratch depth of 200 μm.

(Comparative Example 2)
Polyoxyethylene polyoxypropylene branched decyl ether (trade name: Neugen XL-60 (HLB: 12.5, cloud point measurement / cloud point: 28 ° C. (1% aqueous solution)), manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 25 weight %, Oil-soluble fluorescent dye (trade name: Fluoro 17GA, GAF) 1.0% by weight, each material was weighed so as to have a formulation of 74% by weight of water. A water-washable water-based fluorescent permeation solution in which a single phase was formed by mixing and dissolving was prepared.

The cloudable point (separation temperature) of the washable water-based fluorescent penetrant obtained here was 28 ° C. and there was no flash point.
The flaw detection performance evaluation at a cleaning water temperature of 70 ° C. was “◯” at a scratch depth of 100 μm, “O” at a scratch depth of 150 μm, and “O” at a scratch depth of 200 μm. Since it was difficult to remove, there was a lot of background afterglow and the discriminability from the defect indicating pattern was deteriorated.

(Comparative Example 3)
Anionic surfactant (trade name: Antox EHD-PNA (HLB: none), manufactured by Nippon Emulsifier Co., Ltd.) 10% by weight, oil-soluble red dye (trade name: Oil Red 5B manufactured by Orient Co., Ltd.) 1.0 Each material was weighed so as to have a formulation of wt%, BDG 15 wt%, and water 74 wt%. Under the same conditions as in Example 1, the materials were mixed and dissolved to form a single phase. A washable water-based red penetrant was prepared.

The cloud point (separation temperature) of the washable water-based red penetrant obtained here was not confirmed, and there was no flash point.
The evaluation of flaw detection performance at a cleaning water temperature of 70 ° C. was “x” at a scratch depth of 100 μm, “x” at a scratch depth of 150 μm, and “x” at a scratch depth of 200 μm.

(Comparative Example 4: Washing water amount)
Washing required when washing with water-based water-based penetrant Super Check P-LK (trade name) at a water temperature of 20 ° C. so that the flaw detection evaluation is as shown in (1) to (3) below. The amounts of water were (1) 0.58 L, (2) 0.97 L, and (3) 1.50 L, respectively.
(1) The flaw detection evaluation is “◯” at a scratch depth of 100 μm, “O” at a scratch depth of 150 μm, and “O” at a scratch depth of 200 μm.
(2) In the flaw detection evaluation, “Δ” at a scratch depth of 100 μm, “O” at a scratch depth of 150 μm, and “O” at a scratch depth of 200 μm.
(3) The flaw detection evaluation is “X” at a scratch depth of 100 μm, “△” at a scratch depth of 150 μm, and “◯” at a scratch depth of 200 μm.

According to the penetrant testing method according to the present invention, when the temperature of the penetrant liquid is not less than the cloud point (separation temperature) and the temperature difference between the penetrant separation temperature and the hot water is small, the deep opening defect portion If the temperature difference is large, it is possible to detect up to a minute opening defect portion equivalent to the conventional oil-based permeating liquid, so that the detection accuracy can be easily changed. It is possible to satisfy the requirements of the penetration testing site where the detection defect has various depths, and the penetrant in the present invention has no flash point and meets the standards of the Fire Service Act. Since there is no problem, it can be said that the industrial applicability of the present invention is great.

Claims (4)

A surfactant having a cloud point and water are dissolved in water to form a single phase, and a surfactant is separated from water to have a two-phase state. It consists of a main solvent obtained by mixing two phase states so as to reversibly change with temperature, and an oil-soluble red dye or oil-soluble fluorescent dye dissolved in the main solvent. The water-based penetrating liquid contains 40 to 80% by weight of the water and the oil-soluble dye in a proportion of 0.2 to 2% by weight and does not have a flash point. made by changing the state of the state that is the two phases are to take permeate arising at a temperature above the cloud point of the water-based penetrant, with its phase state is in the single phase Adhering to the surface of the object to be inspected, and penetrating the permeate into the opening defect portion of the surface of the object to be inspected In addition, the surface of the object to be inspected is washed with warm water having a temperature equal to or higher than the cloud point of the penetrating liquid to remove the remaining penetrating liquid without penetrating into the opening defect portion and penetrate into the opening defect portion. A penetrant flaw detection test method for detecting the presence of an opening defect by the permeation liquid penetrating into the opening defect, Depending on the depth of the target opening defect, the temperature difference between the cloud point of the permeate and the temperature of the hot water used for the cleaning is adjusted to detect the presence of the opening defect at the detection target depth. A penetrant testing method characterized by: The surfactant having a cloud point of the penetrant is one or more selected from polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether and polyoxyethylene alkylamine The penetration flaw testing method according to claim 1, wherein: Claim 1 or 2, characterized in that it is formulated the diethylene glycol monobutyl ether in the permeate, one selected from butyl glycol and methyl dipropylene glycol or 2 or more kinds at a rate of 5% to 35% by weight 2. The penetrant testing method described in 1 . Penetrant method according to claim 1, wherein the temperature of the cloud point of the permeate is at a temperature selected within the range of 40 ° C. to 70 ° C..