JPH0464580B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a penetrant testing method for objects whose surfaces exhibit a color other than white, for example, black, and is particularly subject to limitations of the working environment. To provide a penetrant testing method suitable for when it is necessary to perform non-destructive testing work in a state where the safety of workers is ensured.

[Conventional technology]

As is well known, surface opening defects (hereinafter referred to as "defects") such as minute cracks and minute pinholes exist on the surfaces of mechanical parts and weld lines of structures made of metals, plastics, ceramics, etc. ”
That's what it means. As one of the nondestructive testing methods applied to the detection of ), penetrant testing method, which is also standardized as "JIS-Z-2343-1982", is widely used.
This test method involves applying a highly penetrating liquid containing a visible dye (usually red) or a fluorescent dye (usually yellow to yellow-green under ultraviolet light) to the surface to be inspected. After the liquid has penetrated into the defect, excess liquid remaining on the surface of the object to be inspected without penetrating into the defect is removed. If it is difficult to observe, then apply white inorganic fine powder to the surface and use this fine powder to suck out the liquid that has penetrated into the defect to form a defect indication pattern, and observe this indication pattern. This is a test method that detects the presence of defective parts by

The highly permeable liquid used in the above penetrant testing method that dissolves a visible dye is called a ``dye penetrant liquid,'' and the highly penetrant liquid that dissolves a fluorescent dye is called a ``fluorescent penetrant liquid.'' Various formulations are commercially available for "penetrant testing," but they can be roughly divided into "water-based systems," in which visible or fluorescent dyes are dissolved in water and water-soluble organic solvents, and visible or fluorescent dyes. There is an "organic solvent-based system" in which a fluorescent dye is dissolved in an organic solvent. still,
In either system, a surfactant is blended to improve wettability and sufficiently dissolve the dye, and if necessary, a small amount of petroleum-based solvent or plasticizer (DOP, DBP, etc.) is added. BPBG, etc.) are added to further improve wettability.

As shown in the above JIS standard, A.
When a dye penetrant is used, the defect indicator pattern is observed under white light, which is called the "dye penetrant test"method; on the other hand, when a fluorescent penetrant is used, the defect indicator pattern is observed under an ultraviolet lamp in the dark. Observation of defect-indicating patterns is carried out under the ``fluorescence penetration test'' method. The latter method uses clear fluorescence excited by ultraviolet irradiation, so it has a much better ability to indicate defects than the former, but on the other hand, it requires a dark room and a dark room. An ultraviolet lamp (commonly called a black light) is required.

In addition, the white inorganic fine powder used in the penetrant testing method described above includes calcium carbonate, magnesium carbonate, aluminum hydroxide, various silicic acids,
It is a fine powder with a particle size of about 20 microns or less, such as clay, kaolin, bentonite, talc, zinc oxide, titanium white, lithopone (trade name: white pigment made of a mixture of zinc sulfide and barium sulfide), etc.

And, as shown in the above JIS standard,
There are two types: "dry developer", which is applied as a powder only, "wet developer", which is applied by dispersing the powder in water, and "wet developer", which is applied by dispersing the powder in a volatile organic solvent. Quick-drying developer
is commercially available in powder form (dispersed in water by the purchaser), and is commercially available in aerosol spray cans.

In this case, only the white inorganic fine powder is in uniform contact with the surface of the object to be inspected (by immersing it in the powder, holding it, and pulling it up), and the penetrating liquid in the defect is absorbed by the capillary phenomenon between the powder particles in contact. Only the powder that has come into contact with the sucked out penetrant will adhere to the area around the defect, while the powder that has not come into contact with the penetrant will fall off the surface of the inspected object. In other words, the defect indication pattern is small. on the other hand,
The fine white inorganic powder dispersed in a medium (water, volatile organic solvent) adheres to the surface of the object to be inspected together with the medium (by dipping into the dispersion and pulling it up, the dispersion When the medium is volatilized, a white inorganic fine powder layer is formed over the entire surface of the object to be inspected, and the powder layer is formed by capillary action between the powder particles. The penetrating liquid in the defect is sucked out, and the sucked out penetrating liquid oozes out onto the powder layer surface, forming a bleed corresponding to the amount of penetrating liquid in the defect. The instruction pattern is large enough.

When performing penetrant testing as described above, A, B, and are selected and combined as appropriate depending on the type of object to be inspected, work environment, work efficiency, etc. This is also indicated in the JIS standard.

[Problem that the invention seeks to solve]

Now, the surface is colored other than white, especially black, brown,
The above-mentioned method is to conduct a penetrant test on an object exhibiting a dark color such as red, in a work environment where special equipment cannot be prepared, efficiently and while ensuring the safety of workers. If we consider whether or not it is possible to select and combine A, B, .

In other words, it goes without saying that method B cannot be carried out in a working environment where special equipment such as a dark place and a black light cannot be prepared, and method A must be used. Since the defects are minute, ranging from microns to several millimeters, and it is impossible to confirm with the naked eye the dye penetrant that has penetrated into such minute defects, A.
It will be combined with one of the following. However, since it requires a dipping tank,
It cannot be used in work environments that require special equipment such as tanks, and is inefficient because it requires long drying times. Because they require volatile organic solvents, they are dangerous in terms of fire and inhalation toxicity, and there are problems in ensuring the safety of workers. Therefore, it is necessary to carry out the process in combination with A, but when A and or are combined, the color of the dye penetrating liquid will appear on the white background (the surface of the white inorganic fine powder layer). The defect indication pattern appears, and the contrast is extremely good, but
When A and A are combined, a defect indicating pattern exhibiting the color of the dye penetrant appears behind the background color of the surface of the non-inspected object, and the contrast is extremely poor, and the defect indicating pattern itself is small. Its observation is almost impossible. In fact, in "Non-destructive Testing Technology Series - Penetrant Testing A: Japan Non-destructive Testing Association: P17-18: 1976 Edition, 4th Edition, Published February 20, 1980," it states, "...This method It is a method that applies a differential dry developer, and is often applied in combination with post-emulsification fluorescent penetrant testing and water-washing fluorescent penetrant testing.However, it cannot be applied to dye penetrant testing. It has been stated.

Therefore, the inventor of the present invention has developed an object to be inspected whose surface exhibits a color other than white, especially a dark color such as black, brown, or red, in order to improve efficiency in a work environment where special equipment cannot be prepared, and to make it easier for workers to inspect. The present invention was achieved as a result of repeated research aimed at making it possible to conduct penetrant testing while ensuring safety.

[Means for solving problems]

That is, in the present invention, an object whose surface exhibits a color other than white is an object to be inspected, a colorless penetrating liquid containing water is applied to the surface of the object, and the penetrating liquid is applied inside the surface opening defect. After infiltrating into the defect, excess penetrating liquid remaining on the surface of the object to be inspected without penetrating into the defect is removed, and then dry development consisting of white inorganic fine powder and white super absorbent resin fine powder is applied to the surface. A developer is brought into contact with the developer to suck out the penetrating liquid that has penetrated into the defective part, and the sucked out penetrating liquid causes a part of the developer to adhere to the periphery of the defective part, and the attached developer. This is a penetrant testing method for an object whose surface exhibits a color other than white, which is characterized by forming a defect indicating pattern by expanding the fine resin powder contained in the agent by absorbing water.

First, the white super absorbent resin fine powder, which is the most important in the method of the present invention, will be explained. This powder is
“Fusayoshi Masuda: Super absorbent resin: Magazines, functional materials,
April 1982 issue: P36-44: CMC Co., Ltd.: Showa
As stated in "Published April 5, 1957", "...
At first glance, it looks like an ordinary white powder, but when you pour water into it, it instantly absorbs water and turns the entire water into a gel. Its water absorption capacity is hundreds of times greater, meaning that 1g of powder can absorb 500 to 600g of water. can absorb...'',
``...A number of applications have been considered, including toys that gradually expand when immersed in water, sealants and wire coating materials that expand when they come into contact with water and have a waterproof effect, and some have already been put into practical use...'' A typical product is one whose main component is a hydrolyzate of starch graft polymer (usually starch is grafted with acrylonitrile). Yokasei Co., Ltd.
It is commercially available under the names "SPG" (product name: manufactured by Henkel) and "SPG" (product name: manufactured by Henkel).

The present inventor focused on the above-mentioned property of white super absorbent resin fine powder that instantly absorbs water and expands when it comes into contact with water, and realized the idea of using this property to three-dimensionally enlarge a defect indicating pattern. This is what I did.

That is, in the method of the present invention, the above-mentioned white super-absorbent resin fine powder and the above-mentioned white inorganic fine powder, which has conventionally been commonly used in penetrant testing, are used together as a dry developer.

It is preferable to use the above-mentioned white super absorbent resin fine powder with a particle size of 20 microns or less, and this is used to enable a uniform contact when bringing it into contact with the surface of the object to be inspected, and to suck out the penetrating liquid. This is to ensure that there are no problems. It is for the same reason that the white inorganic fine powder conventionally used as a developer for penetrant testing has a particle size of 20 microns or less.

Further, the blending amount of the white super absorbent resin fine powder is preferably 5 to 900 parts with respect to 100 parts by weight of the white inorganic fine powder (hereinafter simply referred to as "parts"), and 5 parts or more. If blended, a large and raised defect indicating pattern that can be easily observed with the naked eye will be formed during use. The larger the amount, the larger the defect indicator pattern formed, but it should be kept at less than 900 parts, which is 10% by weight (hereinafter simply referred to as "%") in the dry developer.
This is because if the above-mentioned white inorganic fine powder is not present, it will be difficult to uniformly contact the surface of the object to be inspected.

The above-mentioned white super absorbent resin fine powder expands in the presence of an extremely small amount of water, and the defects that are subject to penetrant testing are minute micrometers to several millimeters in size. Although the amount of penetrating fluid contained in the defect is very small, if the penetrating fluid contains approximately 30% or more of water, the fine resin powder will absorb the moisture in the penetrating fluid in the defect area and reduce the amount of water by approximately 10%. Expands to more than double its size.

Next, in the method of the present invention, a colorless liquid containing water is used as the penetrating liquid. Roughly speaking, it is the formulation of a water-based dye penetrant solution for penetrant testing without the dye, and in detail, it is 30 to 87% water, 10 to 50% water-soluble solvent, and 3 to 20% surfactant. The water-soluble solvent and surfactant are used to improve wettability and to prevent the penetrant from evaporating before the development process. For this purpose, the former should be at least 10% and the latter should be at least 3%.
%, and the former is 50% or more and the latter is 20%.
% or more, the water absorption expansion of the white super absorbent resin fine powder is inhibited. Suitable water-soluble solvents include carbitol-based solvents such as butyl carbitol and ethyl carbitol, cellosolve-based solvents such as ethyl cellosolve and butyl cellosolve, and glycol-based solvents such as glycerin and propylene glycol. Non-ionic ones are suitable. In addition, in order to further improve the wettability
A small amount of plasticizer or petroleum solvent such as DOP, BPBG, or DBP may be added. Further, a small amount of a fluorescent brightener may be added to the dry developer for the purpose of increasing the whiteness of the dry developer during use.

"Function" The method of the present invention is a penetrant test method performed using the above-mentioned dry developer and the above-mentioned colorless penetrant liquid, and the operation itself is similar to the conventional penetrant test method performed by combining A and A. It will be done. Next, its operation will be explained along with its effects.

The above-mentioned colorless penetrating liquid is applied to the surface of the object to be inspected (for example, a fired black ceramic product) whose surface has been cleaned by a conventional method, and then the colorless penetrant is applied for a specified period of time (usually 5 to 10 minutes).
Leave it alone to allow the penetrant to penetrate into the defect. The penetrating liquid may be attached by immersing the object to be inspected in the penetrating liquid and pulling it up, or by brushing or spraying the penetrating liquid onto the surface of the object to be inspected. Next, the surface of the object to be inspected is wiped with a rag or the like to remove excess penetrating liquid remaining on the surface of the object without penetrating into the defective portion. Next, the dry developer is brought into contact with the surface of the object to be inspected. Contact with the developer powder can also be achieved by immersing the object to be inspected in the developer powder (in a powder tank), holding it in that state for a predetermined period of time (usually 1 to 5 minutes), and then pulling it out. Alternatively, the developer powder may be sprinkled onto the surface of the object to be inspected to a uniform thickness, held in that state for a predetermined period of time (same as above), and then the surface of the object to be inspected is tilted. In either method, the penetrating liquid in the defective area is sucked out by capillary action between particles during holding, and only the developer powder that has come into contact with the sucked out penetrating liquid adheres to the area around the defective part. The developer powder that did not come into contact with the penetrating liquid falls off the surface when it is pulled up or tilted. The white inorganic fine powder in the developer powder adhering to the vicinity of the defective area maintains its size, but the white super-absorbent resin fine powder absorbs water from the penetrating liquid with which it comes into contact, increasing its size. As it expands, a large and raised white defect indicating pattern is formed. This defect indicating pattern appears in white against the background color (for example, black) of the surface of the object to be inspected.
The defect indicating pattern is large and raised, and has good contrast, so it is extremely easy to observe.By combining the conventional A and or, dye penetrating liquid is applied to the back of the white background (the surface of the white inorganic fine powder layer). The defective portion can be detected with the same level of accuracy or higher accuracy than when a defect indicating pattern exhibiting a color (for example, red) is displayed.

〔Example〕

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

Example 1 Preparation of colorless penetrating liquid 70% water, 10% diethylene glycol monobutyl ether (manufactured by Nippon Nyukazai Co., Ltd.) and Nonipol 60
(Product name: Sanyo Chemical Co., Ltd.) 20% was mixed to obtain a colorless penetrant.

Preparation of dry developer Talc with a particle size of 3 to 20 microns (Nippon Talc Co., Ltd.)
20% titanium white (Titan Kogyo Co., Ltd.) with a particle size of 2 to 5 microns, 30% hydrated silicic acid (Carplex #1120, product name: manufactured by Shionogi & Co., Ltd.) with a particle size of 2 to 4 microns ) 20% and white super absorbent resin fine powder with a particle size of 10 to 20 microns (Sunwet 1M-1000MPS:
(trade name: manufactured by Sanyo Kasei Co., Ltd.) 30% to obtain a white dry developer.

Penetrant test: A type A comparative test piece (aluminum alloy quench crack test piece) for sensitivity testing according to the JIS-S-2343 standard with a black-gray surface was used, and the above colorless penetrant liquid was sprayed onto the surface. After being left for 3 minutes, the surface was wiped with a cloth to remove excess penetrating liquid, and then the test piece was immersed in a powder tank filled with the above dry developer, and after being held for 4 minutes, it was pulled out and exposed to white light. When I observed it with the naked eye, I could clearly see a raised white defect indicator pattern on a black-gray background.

In addition, when observed using a magnifying glass, it was found that the white super absorbent resin fine powder particles in the powder particles forming the defect indicator pattern had expanded to about 10 times the size before application. .

Example 2 Preparation of colorless penetrating liquid 50% water, 25% diethylene glycol monobutyl ether (manufactured by Nippon Nyukazai Co., Ltd.), 20% Nonipol 60 (trade name: manufactured by Sanyo Chemical Co., Ltd.), and DOP (Daihachi Chemical Co., Ltd.)
A colorless penetrant solution was obtained by mixing 5% of the product.

Preparation of dry developer: 10% talc as in Example 1, 20% titanium white as in Example 1, silicic anhydride (Aerosil #200, trade name: Nippon Aerosil) with a particle size of 2 to 5 microns.
Co., Ltd.), 20% zinc oxide with a particle size of 1 to 3 microns (Sakai Chemical Co., Ltd.), and 40% of the same white super absorbent resin fine powder as in Example 1 were thoroughly mixed to form a white dry powder. A developer was obtained.

Penetrant test The same penetrant test as in Example 1 was conducted using the above colorless penetrant liquid and the above dry developer.
As in Example 1, a raised white defect indicating pattern on a black-gray background could be clearly seen.

Note that, as in Example 1, the white superabsorbent resin fine powder particles had expanded to about 10 times the size before application.

〔effect〕

According to the method of the present invention, a fluorescent penetrant liquid, a dye penetrant liquid, a wet developer, and a quick-drying developer can be used when performing a penetrant test on a test object whose surface exhibits a color other than white. Since it is possible to obtain a defect indicating pattern that can be easily observed with the naked eye, all of the above-mentioned problems when using these methods can be solved.
In particular, a remarkable effect can be obtained in that safety problems when using a quick-drying developer can be solved.

Furthermore, in the method of the present invention, a penetrant test is carried out using a colorless penetrant, so that the working environment is not contaminated by the dye that occurs when fluorescent penetrants or dyed penetrants are used.

Claims (1)

[Claims] 1. An object whose surface exhibits a color other than white is the object to be inspected, and a colorless penetrating liquid containing water is applied to the surface of the object to be inspected, and the penetrating liquid is allowed to penetrate into the surface opening defects. , remove the excess penetrating liquid remaining on the surface of the object to be inspected without penetrating into the defective part, and then contact the surface with a dry developer consisting of white inorganic fine powder and white super absorbent resin fine powder. The penetrating liquid that has penetrated into the defective part is sucked out, and the sucked-out penetrating liquid causes a part of the developer to adhere to the periphery of the defective part, and is mixed with the adhered developer. A penetrant testing method for an object whose surface exhibits a color other than white, characterized in that a defect indicating pattern is formed by expanding the resin fine powder by absorbing water.