JPS5919845A - Permeating flaw detection - Google Patents

Abstract

PURPOSE:To suppress an occurrence of a background and an overwashing to obtain a clear flaw display by using a nonvolatile permeation liquid of specified composition and a washing liquid of water-alcohol base of specified composition having a surface tension smaller by >=4 dyne/cm than that of the permeation liquid. CONSTITUTION:The nonvolatile permeation liquid composed of 0.5-3 parts oil- soluble dye, 40-80 parts carbitols, 10-40 part water soluble surfactant, and 5- 20 parts nonvolatile aromatic hydrocarbon and the water-alcohol base washing liquid composed of 0.1-2 parts silicon or fluorine surfactant, 2-40 part ethanol and 60-95 parts water and having the surface tension smaller by >=4 dyne/cm than that of said permeation liquid are used. As the oil-soluble dye and water soluble surfactant, the matters conventionally used are acceptable. The carbitols are blended to provide the liquid itself with suitable viscosity and to dissolve the oil-soluble dye. The non-volatile aromatic hydrocarbon is blended to increase a washing property of the oil-soluble dye.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a penetrant flaw detection method, and more specifically, a penetrant flaw detection method that can suppress the occurrence of so-called "background" and "overcleaning" as much as possible, and can provide clear defect indication. It is about the method.

Penetrant testing is generally well known as a typical non-destructive testing method. This method is used to remove microscopic cracks, pinholes, etc. that are open on the surface of metal, ceramics, etc.
It is used to detect defects, and is particularly used for detecting surface opening defects in mechanical parts, and surface opening defects in mechanical parts and welded parts such as storage tanks and piping.

The operating method for this penetrant flaw detection method is as shown below.
It consists of purification.

■ Penetration operator: Penetration made by dissolving an oil-soluble visible dye (usually red) or fluorescent dye (a yellow-green under a normal ultraviolet lamp) on the surface of the object to be inspected, which has been washed to make the surface clean. A strong liquid (usually has a surface tension of 26 to 32 dy'nθ/image, hereinafter referred to as "penetrating liquid") is applied by means such as coating, spraying, or dipping, and is left until the penetrating liquid sufficiently penetrates into the opening defect. .

■Cleaning operation Excess penetrating liquid remaining on the surface of the object to be inspected without penetrating into the opening defect is dissolved, and liquid such as water (hereinafter referred to as "cleaning liquid") is used to wipe it off with a rag or spray cleaning. Remove by means.

■Development operation: In order to suck out the penetrating liquid remaining in the defective part of the opening to the surface and enlarge and reveal the defective part that contained this penetrating liquid, a thin, uniform layer of inorganic white fine powder is applied to the surface of the object to be inspected. to form.

■ After the inspection and development operation, the inorganic white fine powder layer is left to stand for a predetermined period of time, and the penetrating liquid is sucked out to the surface of the layer to reveal a blot pattern indicating defects. If the dye is a visible dye, 6
Defect indications are observed under colored light and, if the dye is a fluorescent dye, under ultraviolet lamp illumination.

Incidentally, the penetrant liquid and cleaning liquid used in the penetrant flaw detection method used in the above-mentioned method have the formulations shown below.

First, the oldest known dye is oil-soluble dye 0.
．． A combination of a penetrating liquid with a composition composition of 5 to 3 double soaked parts (hereinafter referred to as "parts") of 40 to 60 parts of high-boiling esters and 40 to 60 parts of an oily organic solvent, and a cleaning liquid made of a petroleum-based organic solvent. be. In addition, a self-emulsifying penetrating liquid with a composition of 0.5 to 3 parts of an oil-soluble dye, 5 to 20 parts of high-boiling esters, 60 to 80 parts of an oily organic solvent, and 5 to 60 parts of a surfactant, and water. Combinations with cleaning solutions are also well known.

However, when the above-mentioned penetrating liquid and cleaning liquid are used, there is a problem in that their toxicity causes harm not only to the waste water but also to the inspection personnel.

Therefore, in recent years, in an effort to solve the above problems, combinations of water-based penetrants and cleaning solutions that avoid the use of toxic high-point esters and oil-based organic solvents, and combinations of water-based penetrants and water-based cleaning solutions have been developed. Combinations with base cleaning solutions have been proposed. That is, the former is, for example, a cleaning liquid consisting of a penetrating liquid and water with a composition composition of 0.01 to 6 parts of an oil-soluble dye, 5 to 40 parts of a surfactant, and 60 to 90 parts of water, as disclosed in JP-A-50-120389. The latter is, for example, 1 to 1.5 parts of an oil-soluble dye disclosed in JP-A-50-104690, 0.1 to 3 parts of a surfactant, and 0.1 to 3 parts of a water-soluble organic solvent. It is a combination of a penetrating liquid with a composition of 50 to 99.5 ↑ 1μ of water, a surfactant, a water-soluble solvent, and a water-based cleaning solution consisting of water. The actual situation is that this method is hardly put into practical use because the defect display is unclear compared to conventional methods.

In addition, in view of the above-mentioned problems, the present inventor has developed a system that clearly displays defects without using toxic substances, so as not to cause harm to wastewater but also to inspection workers. As a combination of penetrating liquid and cleaning liquid that can be used for
Based on a non-volatile penetrating liquid with a composition of 5 to 50 parts of surfactant, 5 to 15 parts of surfactant, 10 to 40 parts of alcohol, and the balance water/alcohol with a composition of water. We have developed a combination with cleaning liquid.

In the case of the above combination, since the penetrating liquid consists only of non-volatile components, it goes without saying that it does not violate the "Organic Solvent Medium Prevention Regulations" (hereinafter abbreviated as "organic agents"), and during the penetrating operation. There is no risk of poisoning of inspection workers from IIIJ-emitting substances, and if ethanol is selected as the alcohol to be added to the cleaning solution, the cleaning solution itself will also be clean.
It does not conflict with "organic agents". Furthermore, in the case of this combination, defects are displayed during inspection much more easily than in the case of the above-mentioned combination using a water-based penetrant.
It has been improved.

However, compared to the case of a combination using a penetrating liquid using a high-boiling point ester or an oil-based organic solvent, the clear Uα property of defect display was still far from being sufficient. In other words, when removing excess penetrant during cleaning operations, a portion of the oil-soluble dye, which is the only oil-based component in the penetrant composition, tends to be left behind as a cleaning agent on the surface of the test object. In this case, the presence of oil-soluble dye left behind makes the defect indication completely clear during inspection (the contrast between the defect indication pattern on the surface of the inspected object and the other parts becomes poor. "Background"
). However,
If the cleaning residue on the surface of the object to be inspected is eliminated by vigorous cleaning, "background" will not occur, but in this case, even the penetrating liquid that has penetrated into the opening defect will be washed away. , the defect indication is unclear (the defect indication pattern itself on the surface of the inspected object becomes thin, or in extreme cases, the indication pattern does not appear).
It's called "over-cleaning." ).

Note that the above-mentioned two phenomena of "background" and "over-cleaning" may occur not only in the combination of the above-mentioned non-volatile penetrating liquid and water/alcohol-based cleaning liquid; This can also be seen in various combinations of

In view of the above problems, the present inventor conducted further experiments and research, and found that 0.5 to 3 parts of oil-soluble dye was used. A non-volatile penetrating liquid having a composition of 40 to 80 parts of nobitols, 10 to 40 parts of a water-soluble surfactant, and 5 to 20 parts of a non-volatile aromatic hydrocarbon, a silicone-based or fluorine-based surfactant Q,
1 to 2 parts, 2 to 40 parts of ethanol, and 6 to 95 parts of water
and the surface tension of the penetrating liquid is 4.
If all penetrant testing is carried out using a water/alcohol-based cleaning solution with a surface tension lower than dynθ/Cm, there will be no harm caused by wastewater or to the inspection personnel, and it may be possible to do it in one piece. It has also been found that clear defect indications can be obtained by suppressing the occurrence of "over-cleaning" as much as possible.

The compositions of the nonvolatile penetrating liquid and the water/alcohol cleaning liquid were determined as described above for the following reasons.

First, the nonvolatile penetrating liquid will be explained in detail.

As the oil-soluble dye, commonly used dyes may be used, such as Sudan Red-7nC (manufactured by BASF) and Oil Red RR (trade name: Orient Chemical Co., Ltd.), which have been considered suitable for penetrant testing methods. red oil-soluble dye, or flobenol yellow 618 (product name:
Day G1. Fluorescent dyes such as White Fluoro B (trade name; manufactured by Sumitomo Chemical Industries) and the like may be used.

The blending ratio is also within the range commonly used in penetrant testing methods; if it is less than 0.5 parts, practical flaw detection sensitivity cannot be obtained, and if it is blended in excess of 6 parts, the flaw detection sensitivity is too large.
Since no significant improvement could be expected, the amount was set at 0.5 to 3 parts.

Carpitols include, for example, ethylcarbyl and butylcarpitol, and these carpitols are the base material of the non-volatile penetrating liquid used in the method of the present invention, and are used to adjust the viscosity of the liquid itself and to absorb oil-soluble dyes. It is blended for dissolution and needs to be blended in an amount of at least 40 parts. However, the upper limit was set to 80 parts or less depending on the blending ratio of other blended compositions.

The water-soluble surfactant may be one that is commonly used, such as various anionic surfactants and nonionic surfactants that have been conventionally used in penetrant testing methods. The blending ratio must be at least 10 parts or more from the viewpoint of cleaning performance; if it is less than this, the oil-soluble dye cannot be sufficiently washed away during the cleaning operation. In addition, if the amount of the compound is increased, the cleaning performance will improve, but
Since the viscosity of the liquid would also increase and the permeability would decrease, the amount was set at 40 parts or less from the viewpoint of permeability.

Nonvolatile aromatic hydrocarbons include, for example, argylbenzene having 14 or more carbon atoms, alkylnaphthalene having 11 or more carbon atoms, bisphenol, diphenylene, and the like, which easily dissolve oil-soluble dyes and are water-soluble. It is easily dissolved in surfactants and calpitols, and is added to improve the cleaning properties of oil-soluble dyes. The blending ratio should be at least 5 parts or more in order to make the above-mentioned oil-soluble dye have good cleaning properties, and if the blending ratio is too high, the non-volatile aromatic hydrocarbon itself Since it is an oil-soluble substance, the cleaning performance is rather poor, so the practical limit of 20
It was set as below.

The non-volatile penetrating liquid formulated as described above is 29-32
ayne/Cn1 surface tension, and has practically sufficient permeability (AM).

Next, the water/alcohol-based cleaning solution will be explained in detail.

The most important point regarding the water/alcohol-based cleaning solution used in the method of the present invention is that a silicone-based or fluorine-based surfactant is used as the surfactant.

That is, as mentioned above! The small volatile penetrating liquid used in the method of the present invention is formulated with a predetermined amount of non-volatile aromatic hydrocarbon to improve the cleaning performance and prevent oil-soluble dyes from being removed during the cleaning operation in penetrant testing. This eliminates as much as possible the tendency for some parts to be left behind as cleaning residue. Therefore, if this non-volatile penetrating liquid is used in combination with a water/alcohol-based cleaning liquid, "background" will hardly occur, but there is still an inherent tendency for "over-cleaning" to occur.

The inventors of the present invention have found that (as a result of extensive experiments and research) the above-mentioned tendency to transient cleaning is caused by the surface tension between the penetrating liquid and the cleaning liquid.

That is, conventionally, the relationship between the surface tension between the penetrating liquid and the cleaning liquid is such that the surface tension values for both are approximately the same (26 to 32 d).
ynθ/ai), but when a penetrating solution is combined with a cleaning solution that has a surface tension smaller than that of the penetrating solution, the cleaning solution quickly removes the excess penetrating solution on the surface of the object to be inspected. Therefore, the cleaning time required to remove the excess permeate, in other words, the contact time between the excess permeate and the cleaning liquid required to remove the excess permeate is shortened. I found something useful. In addition,"
The "successive flicking off" phenomenon mentioned above means that when excess penetrant is in contact with the surface of the object to be inspected, if a cleaning solution with a surface tension lower than that of the penetrant is present, the cleaning solution will A phenomenon in which the cleaning liquid sinks under the excess penetrant and pushes away the excess penetrant because the wettability of the surface of the test object is greater than the wettability of the penetrant that was in contact with the surface of the test object first. This will occur significantly if the difference in surface tension between the two is 4 sne/Cm or more.

Cleaning necessary to remove dirt and excess permeate.

The shorter the time, the less chance some of the penetrating liquid that has penetrated into the open defect will flow out onto the surface of the object to be inspected, and the tendency to "overclean" can be eliminated as much as possible. . Furthermore, in the above phenomenon, when the cleaning liquid pushes away the excess penetrating liquid, the cleaning liquid acts to push those living near the opening defect into the defect. It can be inferred that this suppresses the outflow of a part of the penetrating liquid within the opening defect.

Therefore, in view of the above phenomenon, the present inventor conducted various studies on means for lowering the surface tension of water/alcohol-based cleaning liquids, and found that if a silicone-based or fluorine-based surfactant is used as a surfactant in a water/alcohol-based cleaning liquid, The headline is that surface tension can be lowered. Regarding the blending ratio, it is necessary to mix at least 0.1 part or more to cause the above phenomenon, and the above phenomenon becomes more pronounced as the blending amount increases, but up to 2 parts Since a sufficient effect can be obtained for practical use, the blending ratio is 0.
Parts 1 and 2.

In addition, the above silicone-based or fluorine-based surfactant may be added in an amount of 0.1 to
The surface tension of the water-alcohol-based cleaning solution itself when mixed in the range of 2 parts is 20 to 24 dynθ/I:fn
becomes. In addition, the surface tension ability of silicone-based or fluorine-based surfactants acts specifically on water, so even if they are blended as water-soluble surfactants for the above-mentioned non-volatile θ permeation liquid. Since there is no water present in the composition of the non-volatile permeate, its surface tension hardly decreases.

Ethanol is blended as a cleaning aid,
It supplements the cleaning ability of water, but at the same time it also has the effect of promoting the above-mentioned ``quickly repelling'' phenomenon. Regarding this blending ratio, in order to effectively exhibit the above-mentioned promoting effect, at least 2 parts or more is required, and if it is blended in excess of 40 parts, the above phenomenon will be weakened, so There were 40 copies.

In addition, instead of the above ethanol, methanol etc.
Although the same effect can be obtained even if the ethanol is blended with ethanol, ethanol was selected for use in the method of the present invention in consideration of the "organic rule."

Water is the base material of the water/alcohol-based cleaning solution used in the method of the present invention, and the remainder of the other ingredients listed above, usually 60%
~95 parts are blended.

In addition, a rust preventive agent may be added to the water/alcohol paste cleaning solution containing the above-mentioned ingredients according to a conventional rc method, if necessary.

The present invention performs penetrant testing using a combination of the above-described non-volatile penetrating liquid and a water/alcohol-based cleaning liquid, and the operation itself is exactly the same as each of the conventional operations (1) to (4) described above.

In the present invention, during the cleaning operation (2), the nonvolatile aromatic hydrocarbons in the nonvolatile penetrant are used to prevent oil-soluble dyes from remaining after cleaning as much as possible when excess penetrant is removed. The non-volatile penetrant that has penetrated into the opening defect can flow out due to the difference in surface tension between the non-volatile penetrant and the water/alcohol-based cleaning solution. ``over-cleaning'' is prevented.
This rarely occurs, and a clear defect indication can be obtained during the inspection of (3).

The inorganic white fine powder used in the developing operation (2) may be, for example, silicic acid fine powder, which is commercially available as a developer for penetrant testing.

As described above, according to the present invention, it is possible to suppress the occurrence of so-called "background" and "over-cleaning" as much as possible and obtain clear defect indications, as well as to obtain clear defect indications specified on the "organic side". The safety of the surface to be inspected is guaranteed because no organic solvent is used.The water/alcohol-based cleaning solution used in the present invention also contains 0.1 to 2 surfactants in its formulation.
Since only 1.5% of the cleaning fluid is mixed, there is less foaming and workability is better compared to conventional water-based cleaning fluids or water/alcohol-based cleaning fluids.

Next, a more detailed explanation will be given based on an example.

[Example 1] - Non-volatile penetrant liquid composition Sudan Red-7E (product name: 5ASIr) 1.5
Parts Eilcarpitol 60 parts Octylphenol ethoxylate 30 parts Methylnaphthalene 8.5 parts - The surface tension of the penetrating liquid with the above composition is 31.8 ay.
ne/crn.

・Water/alcohol-based cleaning solution Silicone surfactant SP (manufactured by Shin-Etsu Chemical) 0.5 parts Ethanol 20 parts Water
79
Part triethanolamine (corrosion inhibitor) [J, 5 parts - The surface tension of a cleaning solution with the above composition is 21.4 ayne7
It is a name.

Penetrant testing was carried out as follows using a non-volatile penetrating liquid with the above composition and a water/alcohol based cleaning solution.

Ultrasonic cleaning using acetone was performed for 20 minutes as pre-cleaning, and the surface of the "weld line regulation test piece" was air-dried.
The above non-volatile penetrating liquid was applied by brushing, and
Leave it for a minute.

Thereafter, excess penetrating liquid on the surface of the test piece was wiped off with a rag impregnated with the above-mentioned water/alcohol-based cleaning solution.

The excess penetrant was completely removed by wiping twice.

Next, a thin layer of inorganic white fine powder was applied to the surface of the test piece using a commercially available
It was formed using dry developer D-LTJ' (manufactured by Special Paint ■), and after 5 minutes, the surface of the test piece was observed under white light.The defect display blot pattern clearly indicated even the smallest defects. was clearly recognized.

For comparison, a commercially available non-volatile penetrating liquid ("Dyeing Penetrating Liquid P-LTJ" made by Special Paint ■) and a commercially available water/alcohol-based cleaning solution ("Cleaning Liquid R-LT" made by Special Paint ■) were used. When compared with the case where the above-mentioned penetrant detection (J5) was performed in combination, it was confirmed that in the case of the present invention, finer defects were detected and the color of the bleeding pattern was also darker.

[Example 2] ・Non-volatile penetrating liquid composition Solovenol Yellow 618 (i [Product name 2 DayG
1o Company i) 0.5 parts White Fluoro B (Product name 2 manufactured by Sumitomo Chemical Industries) 0.5
Parts Butyl Calpitol 70 Parts Polyquine Ethylene Dioleate 2 Parts Dodecylbenzene 9 Parts The surface tension of the penetrating liquid having the above composition is 30.2 ayne.

・Water/alcohol-based cleaning liquid Fluorine surfactant Megafac F=20 (Dainippon Ink & Chemicals) 0.2 parts Ethanol 30 parts Water 69
．． 5 parts Sodium nitrite (rust preventive agent) 0.5 parts The surface tension of the cleaning solution having the above composition is 20.4 a n
e/Cm.

Penetrant testing was carried out as follows using a non-volatile penetrating liquid with the above composition and a water/alcohol based cleaning solution.

“NDIS-
The non-volatile penetrating liquid was applied to the left half of the human-shaped test piece (a 2024s-ACC alloy side split test piece with a groove for comparison testing in the center), with the groove on the surface as the border, and the right side. For comparison, a commercially available non-volatile penetrating liquid ("Fluorescent Penetrating Liquid 0D-28001", manufactured by Special Paint ■) was applied to each half by spray coating, and then left for 15 minutes. After that, the excess penetrant on the surface of the test piece was removed from the left half using a cloth impregnated with the non-volatile penetrating solution, and from the right half.
For one thing, the commercially available water used for comparison in [Fruit Fabric Example 1]
With a rag soaked in an alcohol-based cleaning solution,
I wiped each one off. In this case, the ease of wiping was almost the same for both.

Next, the test piece was buried in a commercially available dry developer DN-600p-IJ (made by special paint), which is an inorganic white fine powder, for 5 minutes, then pulled out, and then placed under an ultraviolet lamp. When the surface of the test piece was observed, it was found that finer defects were more clearly indicated on the left half of the test piece than on the right half.

Example - Composition of non-volatile penetrating liquid Oil Red RR (trade name: Orient Chemical Co., Ltd.) 2 parts Butyl carpitol 65 parts Nonylphenol ethoxylate 25 parts Diisopropyl naphthalene 8 parts The surface tension of the penetrating liquid having the above composition is 3 [ ], 5 ay n e
/cm.

ψWater/alcohol-based cleaning liquid silicone surfactant X-45D9 (Shin-Etsu Chemical @)
1 part ethanol 10 parts water
88 Kure dicyclohexylamine nitrite (rust inhibitor)
The surface tension of the cleaning solution with the above composition υ is 20.8a
y n eA7n.

The following continuous penetrant testing was carried out using a non-volatile penetrant liquid with the above composition and a water/alcohol based cleaning solution.

The same pre-cleaning as in [Example 1] (however, the cleaning time was 10 minutes) was carried out to prepare rND engineering s-B type test pieces) (tu-
Two Or-plated bending crack test pieces with an opening defect of 50μ in depth and 5μ in lJ were used, and the -
The surface of the piece was coated with the above non-volatile penetrating liquid, and the surface of the remaining piece was coated with the commercially available non-volatile penetrating liquid used for comparison in [Example 1] (=J The former test piece is hereinafter referred to as test piece N1, and the latter test piece is referred to as test piece B.

After that, each test piece was tilted at an angle of about 45° and set up.
t21. , one drop of the above water/alcohol-based cleaning solution was applied to the surface of the test piece B, and on the surface of test piece B [Actual IM Example 1]
One drop of the commercially available water/alcohol-based cleaning solution used for comparison was applied to the upper end of each test piece. As a result, it was observed that on the surface of the test piece, as the Mizuko alcohol-based cleaning solution descended, the excess penetrating solution was repelled from side to side and flowed down with the cleaning solution, and about 5 seconds after dropping, Excess penetrating liquid on the surface of the test piece had been removed as far as the naked eye could see. On the other hand, on the surface of test piece B, only the excess penetrating liquid present in the descending path of the cleaning liquid flowed down with the cleaning liquid and was removed. The phenomenon of spreading was not observed.

Next, the surface of test piece A was wiped with an empty rag, and the surface of test piece B was wiped with a rag soaked in the above-mentioned commercially available water/alcohol-based cleaning solution. A thin layer of inorganic white fine powder was formed using the commercially available dry developer D-jJTJ used in Example 1.

After 5 minutes, the surface of each test piece was observed under white light, and the color of the defect bulletin pattern appearing on the surface of test piece A was more pronounced than that appearing on the surface of test piece 3. It was confirmed that the color was dark.

Patent applicant: Sumitomo Metal Industries, Ltd. Same Special Paint Co., Ltd.

Claims (1)

[Claims] (1), 0.5 to 3 parts of oil-soluble dye, 40 to 80 parts of carpitol, 1 to 10 to 40 parts of water-soluble surfactant
a non-volatile penetrating liquid having a composition of 5 to 20 parts by weight of a non-volatile aromatic hydrocarbon, 0.1 to 0.1 to ZBt gold parts of a silicone-based or fluorine-based surfactant, 2 to 40 parts by weight of ethanol, and 6 to 6 parts by weight of water. IM is carried out to detect defects on the surface of the material to be inspected using a water/alcohol-based cleaning liquid having a composition of 95 parts and a surface tension smaller than the surface tension of the penetrating liquid by p4dynθ/c1n or more. Penetrant testing method.