JPH0464579B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement of a dry developer for penetrant flaw detection and a penetrant test method using the improved dry developer.

[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 liquid containing a visible dye (usually red) or a fluorescent dye (usually yellow to yellow-green under an ultraviolet lamp) to the surface to be inspected, and then applying the liquid into the defect. After the infiltration, remove the excess liquid that has not penetrated into the defect and remains on the surface of the object to be inspected. A white inorganic fine powder is applied to the surface, and the fine powder sucks out the liquid that has penetrated into the defect to form a defect indicating pattern.By observing this indicating pattern, the presence of the defect can be detected. This is a method of detecting

The liquid used in the above-mentioned penetrant testing method in which visible dye is dissolved is called "dye penetrant liquid", and the liquid in which fluorescent dye is dissolved is called "fluorescent penetrant liquid", and there are various types of liquids. Formulated products are commercially available as "for penetrant testing," but they can be roughly divided into "water-based systems," in which visible or fluorescent dyes are dissolved in water or water and water-soluble organic solvents, and "water-based systems," in which visible or fluorescent dyes are dissolved in water or water and water-soluble organic solvents. There is also an ``organic solvent-based type'' that is dissolved in an organic solvent. And A "dye penetrant"
When using a dye penetrant test, the defect indicator pattern is observed under white light.
On the other hand, when B "fluorescent penetrant liquid" is used, it is called "fluorescent penetrant testing", and the defect indicator pattern is observed in a dark place under irradiation with an ultraviolet lamp (usually called black light). is being carried out.

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 of clay, kaolin, bentonite, talc, zinc oxide, titanium white, lithopone (product name: white pigment consisting of a mixture of zinc sulfide and barium sulfate), etc., with a particle size of approximately 20 microns or less, and meets the JIS standards listed above. As shown, 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 one in which the powder is dispersed in a volatile organic solvent. There are so-called "quick-drying developers" that are applied as a spray, and are commercially available in powder form (dispersed in water by the purchaser) and are applied in an aerosol spray can. It is commercially available in the form

The penetrant testing method described above is A, B,
and are carried out in appropriate combinations depending on the required flaw detection accuracy, work efficiency, work environment, etc.
A, B, and each have their own advantages and disadvantages, and there are cases where it is said that they cannot be combined.

That is, first, since B uses fluorescence excited by ultraviolet irradiation, its defect indicating ability is far superior to A, but on the other hand, it requires a dark place and a black light.

Next, white inorganic fine 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 it into the dispersion and pulling it up). , by aerosol spraying of a dispersion liquid), and by volatilization of the medium, a white inorganic fine powder layer is formed over the entire surface of the object to be inspected, and the capillary tubes between the powder particles forming the powder layer are formed. This phenomenon causes the penetrant in the defect to be sucked out, and the sucked-out penetrant oozes out onto the surface of the powder layer, forming a bleed corresponding to the amount of penetrant in the defect.
In other words, the defect indicating pattern is sufficiently large, but on the other hand, only the white inorganic fine powder is in uniform contact with the surface of the object to be inspected (by immersion, holding, and pulling up into the powder), and the powder particles in contact are The penetrating liquid inside the defect is sucked out by the capillary phenomenon between the two, and only the powder that has come into contact with the sucked out penetrating liquid adheres to the area around the defect, while the powder that has not come into contact with the penetrating liquid falls off from the surface of the inspected object. Therefore, the powder adhering to the vicinity of this defect, in other words, the defect indicating pattern, is small.

Since fluorescence is used not only when B and B are combined, but also when B and B are combined, it is easy to observe the defect indicating pattern, but when A and B are combined, Observation of defect-indicating patterns becomes extremely difficult, and sometimes impossible. To be more specific, when the dye penetrating liquid uses red dye, for example, the red color appears on the background of the white background (the surface of the white inorganic fine powder layer) and the contrast is very good, but in the case of They appear in red against the background color, and if the surface of the object to be inspected is black or dark, the contrast is extremely poor, and the defect indicator pattern itself is so small that it is almost impossible to observe it. . Therefore, the actual situation in the industry is that A and A are never combined, and when they are used, they are exclusively combined with B. In fact, "Non-destructive testing technology series/penetrant testing A: Japan Non-destructive Testing Association: P17-
18: 1976, 4th edition, published February 20, 1982" states, "...This method uses a fine white powder dry developer, and is suitable for post-emulsification fluorescent penetrant testing and water-washing fluorescent penetrant testing. It is often applied in combination with testing. However, it cannot be applied to dye penetrant testing...".

On the other hand, there are problems in that it requires a large tank containing the dispersion liquid, a drying device, and long drying times, and it is dangerous in terms of fire and inhalation toxicity because it requires a volatile organic solvent. While there is a problem that there is, there is no such problem.

[Problem that the invention seeks to solve]

By the way, when implementing B, a dark place and a black light are required, so if you are working outdoors or in a work environment without a power source, you have no choice but to use A, but in this case it cannot be combined with the above method. However, when the object to be inspected is a welded line inside a huge tank, it is impossible to combine it with or because of the problems mentioned above. Due to the problems mentioned above, there are serious problems in terms of deterioration of the working environment and safety.
However, if combination with A becomes possible, these problems can be solved at once.

Therefore, the present inventor conducted repeated research aimed at improving the shortcoming of the defect indicator pattern being small, and as a result, the present invention was achieved.

[Means for solving problems]

That is, the present inventor added a dry developer for penetrant testing consisting of a white inorganic fine powder with a particle size of 20 microns or less to an amount equivalent to 5 to 95% by weight of the inorganic fine powder with a white super absorbent particle size of 20 microns or less. A water-absorbing and swelling dry developer for penetrant testing (hereinafter referred to as "1") containing fine resin powder.
It is called the ``th invention''. ), a water-based penetrant dye penetrant liquid containing water and visible dye is applied to the surface of the inspected object, and the penetrant liquid penetrates into the defective part. The excess penetrating liquid remaining on the surface of the object to be inspected is removed, and then the water-absorbing and swelling dry developer for penetrant testing according to the first invention is brought into contact with the surface to remove the penetrating liquid that has penetrated into the defective part. and causing a part of the developer to adhere to the periphery of the defective part by the sucked-out penetrating liquid, and at the same time causing the fine resin powder blended in the adhered developer to absorb water and expand. This is a completed penetrant testing method (hereinafter referred to as the "second invention"), which consists of forming a defect indicating pattern by the method of the present invention.

[Effect]

First, the most important white superabsorbent resin fine powder in the first and second inventions will be explained. This powder is produced by "Fusayoshi Masuda: Super absorbent resin: Magazine/Functional Materials/April 1982 issue: P36-44:
CMC Co., Ltd.: Published on April 5, 1981.'' As stated in ``...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-absorbing power is hundreds of times higher, meaning that 1g of powder can absorb 500 to 600g of water...","...A toy that gradually expands when immersed in water, and expands when it comes in contact with water. Numerous applications have been investigated, such as sealants and wire coating materials that exhibit water-stopping effects, and some have already been put into practical use. Typical products are products whose main component is the hydrolyzate of ``SUNWETT 1M-300MPS'' (product name: Sanyo Chemical Co., Ltd.) and ``SPG'' (product name: Henkel Co., Ltd.). It is commercially available under the name "Made in Japan". still,
“Sunwet 1M-” currently on the market
The particle size of ``300MPS'' is approximately 20 to 40 microns, but the particle size can be easily reduced by crushing it using a ball mill.
It can be 20 microns or less. 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.

Next, the first invention will be explained. The dry developer for penetrant flaw detection made of white inorganic fine powder with a particle size of 20 microns or less in the present invention is a commercially available product called the above-mentioned "dry developer." In the present invention, an amount corresponding to 5 to 95% by weight of the inorganic fine powder is replaced with the white super absorbent resin fine powder having a particle size of 20 microns or less.

It is necessary to use the above-mentioned fine resin powder with a particle size of 20 microns or less, and this is done in order to enable uniform contact when bringing it into contact with the surface of the object to be inspected, and to ensure that there is no problem in sucking out the penetrating liquid. This is for the purpose of 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.

Furthermore, if at least 5% by weight of the inorganic fine powder is replaced with the resin fine powder, a large and raised defect indicating pattern that can be easily observed with the naked eye can be formed during use. The larger the amount of the fine resin powder, the larger the defect indicator pattern formed, but the replacement amount must be up to 95% by weight, and at least 5% by weight of the fine inorganic powder must be present. If not, it will be difficult to make uniform contact with the surface of the object to be inspected. In addition, in practical terms, it is preferable to replace 20 to 70% by weight with the above resin fine powder.

It should be noted that the fine resin powder described above expands in the presence of an extremely small amount of water, and the defects that are subject to penetrant testing are minute microns to several millimeters in size. Although the amount of penetrating liquid that has penetrated into the defective part is very small, as long as the penetrating liquid is water-based, the fine resin powder absorbs about 10 times the moisture in the penetrating liquid inside the defective part. Expands to a larger size.

Therefore, when performing penetrant testing using the water-swellable dry developer for penetrant testing according to the first invention in combination with A or B, if the penetrating liquid is water-based, The inorganic fine powder among the powders that adhere to the surface maintains the same size, but the resin powder absorbs moisture from the water-based penetrating liquid that it comes into contact with and expands, resulting in large and raised defect indicators. A pattern is formed. Although the combination with A is not sufficient in terms of contrast, the defect indication pattern is large and raised, so
The observation is easy, and as a result, the defective part can be detected with the same or higher accuracy than the combination of A and A.

Next, the second invention will be explained. Briefly speaking, this invention uses the water-absorbing swellable dry developer for penetrant flaw detection according to the first invention and a water-based dye penetrating liquid, and the operation is the same as the conventional penetrant flaw detection method in combination with A. It is done in exactly the same way.

A water-based dye penetrating solution is one in which a water-soluble visible dye is dissolved in water, or an oil-soluble visible dye is dissolved in water and a water-soluble organic solvent such as diethylene glycol monobutyl ether. Usually, a red dye is used. ing. A typical water-based dye penetrant solution is one made by dissolving an oil-soluble red dye in water and diethylene glycol monobutyl ether. )”, “Super Check P-
LT・1 (Product name: Tokushu Toyo Co., Ltd.), Super Check P-G・L (Product name: Tokushu Toyo Co., Ltd.)
These commercially available products are approximately
Contains 40-70% water by weight.

The function of the second invention together with its operation will be explained as follows. A water-based dye penetrating solution is applied to the surface of the object to be inspected, which has been cleaned by a conventional method, and left for a predetermined period of time (usually 5 to 10 minutes) to allow the penetrating solution to penetrate into the defective area. 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 water-absorbing expansion dry developer for penetrant testing according to the first aspect of the invention 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 on 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, which does not come into contact with the penetrating liquid, falls off the surface when it is pulled up or tilted. The developer powder adhering to the vicinity of the defective portion is colored in the same color as the penetrating liquid, and the fine resin powder contained in the powder absorbs moisture in the penetrating liquid and swells. In this way, a large and raised defect indicating pattern is formed around the defective part, which is made up of the fine inorganic powder colored in the color of the penetrating liquid and the fine resin powder which is colored in the same way as the expanded resin powder. .

〔Example〕

Examples of the first and second inventions will be described.
In addition, "%" means weight %.

Example 1 Preparation of a water-swellable dry developer for penetrant testing Hydrous silicic acid (Carplex #1120: trade name: manufactured by Shionogi & Co., Ltd.) with a particle size of 2 to 4 microns, 20%, particle size of 2 to 10 microns Calcium silicate (Tomita Pharmaceutical)
Co., Ltd.), 40% talc (made by Nippon Talc Co., Ltd.) with a particle size of 3 to 20 microns, and white super absorbent resin fine powder with a particle size of 5 to 15 microns (Sunwet 1M-
1000MPS (trade name: Sanyo Chemical Co., Ltd.) 30% was thoroughly mixed to obtain a dry developer.

Penetrant test A water-based dye penetrating liquid (Super Check P-
LT・1: Product name: Tokushu Toyo Co., Ltd. - red color, water content 40% -) was spray applied and left for 5 minutes.
The surface was wiped with a cloth to remove excess penetrating liquid, and then the test piece was immersed in a powder bath filled with the above dry developer, held for 4 minutes, pulled out, and observed with the naked eye under white light. The raised defect indication pattern could be clearly seen. 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. .

For comparison, the penetrant test was conducted using a dry developer consisting of 30% hydrated silicic acid, 20% calcium silicate, and 50% talc, but the defect indication pattern in this case was unclear. Observation with the naked eye was extremely difficult.

Example 2 Preparation of a water-swellable dry developer for penetrant testing Silicic anhydride (Aerosil #
200: Product name: Made by Nippon Aerosil Co., Ltd.) 5%, magnesium carbonate with a particle size of 1 to 2 microns (Tomita Pharmaceutical Co., Ltd.)
Co., Ltd., 20% of the same talc as in Example 1, and 60% of the white super absorbent resin fine powder as in Example 1 were thoroughly mixed to obtain a dry developer.

Penetrant test A water-based dye penetrating solution (Super Check UP-G,
W: Product name: Manufactured by Tokushu Toyo Co., Ltd. - Red color, water content 65
%-) was spray applied, left for 5 minutes, the surface was wiped with a cloth to remove excess penetrating liquid, and the test piece was then immersed in a powder tank filled with the above dry developer and held for 4 minutes. After that, when it was pulled up and observed with the naked eye under white light, a red raised defect indicator pattern could be clearly seen.

For comparison, the above penetrant test was conducted using a dry developer consisting of 15% silicic anhydride, 40% magnesium carbonate, and 45% talc, but the defect indication pattern in this case was unclear and invisible to the naked eye. Observation was difficult.

〔effect〕

The first invention is for the implementation of penetrant testing method.
Defect indication patterns that can be easily observed with the naked eye can be obtained without using wet or quick-drying developers.
All of the problems mentioned above when using a wet developer or a quick-drying developer are solved. In particular, the first invention has great industrial applicability because safety problems when using a quick-drying developer are solved.

In addition to the above-mentioned effects of the first invention, the second invention provides a method for penetrant testing that can be easily performed with the naked eye without using a fluorescent penetrating liquid that requires a dark place and a black light. Since an observable defect indicating pattern is obtained, there is a remarkable effect that flaw detection work can be carried out without being restricted by the working environment.

Claims (1)

[Scope of Claims] 1. A dry developer for penetrant testing consisting of white inorganic fine powder with a particle size of 20 microns or less containing 5 to 95% of the inorganic fine powder.
A water-absorbent, water-swellable dry developer for penetrant testing, which contains white super-absorbent resin fine powder with a particle size of 20 microns or less in an amount corresponding to the weight percent. 2. After applying a dye penetrant liquid for penetrant testing containing water and a visible dye to the surface of the object to be inspected and allowing the penetrant to penetrate into the surface opening defect, the surface of the object to be inspected is coated without penetrating into the defect. The excess penetrating liquid remaining on the surface is removed, and then a dry developer for penetrant testing consisting of white inorganic fine powder with a particle size of 20 microns or less is applied to the surface in an amount equivalent to 5 to 95% by weight of the inorganic fine powder. Particle size
The penetrant liquid that has penetrated into the defect area is sucked out by contacting with a water-absorbing and swelling dry developer for penetrant testing, which is made of fine white super absorbent resin powder of 20 microns or less, and sucking out the penetrant liquid. A part of the developer is attached to the periphery of the defective part, and the fine resin powder contained in the attached developer is expanded by water absorption, thereby forming a defect indicating pattern. Characteristic penetrant testing method.