GB2098233A - Inspection penetrant for capillary flaw detection methods - Google Patents

Abstract

A penetrant composition for flaw detection by capillary methods, comprises the following components in percent by mass:- fluorescent dye 0.1 to 4.0 surfactant 2.0 to 10.0 solvent for the fluorescent dye 27.9 to 63.0 oxygen-containing organic compound 30.2 to 60.5 visible-colour dye 0.8 to 1.5 The inspection penetrant composition may further contain a metal corrosion inhibitor. The composition provides differentiation of the depth of the cracks. The fluorescent dye is preferably a naphthobenzimidazole and the visible dye a xanthene or phenazine. The solvent may be a diaryl alkane or a hydrogenated naphthalene and the oxygen-containing compound a butyl or propyl alcohol or propylene carbonate. The surfactant is preferably an alkyl phenol ether of polyethylene glycol and the corrosion inhibitor a polyethylene glycol or a mixture of cyclohexylamine and a fatty acid.

Description

SPECIFICATION Inspection penetrant for capillary flaw detection methods The present invention relates generally to nondestructive testing, and is particularly concerned with inspection penetrants for flaw detection by capillary methods.

Inspection penetrants for capillary flaw detection methods are designed for detecting surface defects in all types of metals used for critical components and products, e.g. in turbine, aircraft, ship building and other industries, as for flaw detection in products fabricated from plastics and other synthetic materials, glass or ceramics.

The present invention provides an inspection penetrant for flaw detection by capillary method, comprising a fluorescent dye, a surfactant, and a solvent system representing a mixture of at least one solvent for the fluorescent dye and at least one oxygen-containing organic compound, which penetrant composition further comprises, according to the invention, a visible-colour dye, with the proportions of the components taken in percent by mass being as follows: fluorescent dye 0.1 to 4.0 surfactant 2.0 to 10.0 solvent for the fluorescent dye 27.9 to 63.0 oxygen-containing organic compound 30.2 to 60.5 visible-colour dye 0.8 to 1.5 Incorporation of the visible-colour dye into the penetrant formulation provides the differentiation of the revealed defects with respect to depth, in case of the fluorescent method of flaw detection, due to different colouration of indication traces of the defects over 0.3-0.4 mm in depth and as compared to the defects less than 0.3-0.4 mm in depth. This arises from the fact that at the step of removing excess penetrant composition from the surface to be tested, said penetrant is easier washed away from the shallow defects than from the deep ones.Thus, the developer coating above the deep defects is turned to a colour of the visible-colour dye tinged with a colour of the fluorescent dye, while the fluorescent indication traces of the shallow defects are turned to a colour of the fluorescent dye slightly tinged with a colour of the visible-colour dye.

The deep defects i.e. defects over 0.3-0.4 mm in depth can also be revealed under white lighting conditions.

Thus, interrelated influence of the fluorescent dye and of the visible-colour dye provides the differentiation of the revealed defects with respect to depth and results in an enhanced sensitivity of the penetrant system and in improved colouring properties thereof.

Incorporation of the visible-colour dye in an amount less than 0.8 mass % into the penetrant composition is deficient to provide reliable flaw detection, while it is inexpedient to use the visible-colour dye in an amount over 1.5 mass %, since the visible-colour dye in an amount of between 0.8 to 1.5 mass % is sufficient for complete flaw detection.

Suitable visible-colour dyes are alcohol soluble dyes of the xanthene group.

It is advisable to use as the alcohol soluble visible-colour dye tatraethyl diamino-o-carboxy phenyl xanthenyl chloride C28H3,03N2CI, molecular mass 479.02, having the following structural formula:

This dye fluorescent both under white light and under black light is a reddish violet powder, nontoxic, soluble in water, alcohol and acetone.

The suitable alcohol-soluble dye is also 3amino-6-dimethylamino-2-methyl phenazine hydrochloride Cr5H N4HCI, molecular mass 288.8, having the following structural formula:

This dye is a greyish black powder soluble in water and alcohol, the water solution of said dye changing to a crimson colour, while the alcohol solution changes to a brownish-red colour.

It is also advisable that the inspection penetrant composition comprise additionally a metal corrosion inhibitor, the proportions of the components taken in percent by mass being in this case as follows: fluorescent dye 0.1 to 4.0 surfactant 2.0 to 10.0 solvent for the fluorescent dye 27.9 to 62.5 oxygen-containing organic compound 30.2 to 50.5 visible-colour dye 0.8 to 1.5 corrosion inhibitor 0.5 to 10.0 The. metal corrosion inhibitor is to be incorporated into the penetrant composition to prevent highly detrimental corrosion processes arising in fabricating and maintenance of equipment.

In the process of testing, as the inspection penetrant fills the flaws, when applied over the workpiece, and is then drawn up from the flaw cavities with the aid of a developer to form dye tracers, some of the liquid inspection penetrant composition remains over the walls of the flaw cavities. Thus, when a corrosion inhibitor is incorporated in the penetrant composition using solvents with high adhesive properties, effective anticorrosive coatings will be formed on the flaw cavity walls.

Suitable corrosion inhibitors are a mixture of cyclohexylamine and fatty acids, an aliphatic alkyl amine, polyethylene glycol.

A mixture of cyclohexylamine and fatty acids contains 31 to 34 mass % of cyclohexylamine, the balance being fatty acids. Said corrosion inhibitor is a water- and oil-soluble inhibitor Aliphatic alkyl amines are compounds having Cr5 to C18 alkyl chains and soluble in alcohols, hydrocarbons, and water.

Polyethylene glycols with a molecular mass of from 300 to 1,500 provide good inhibiting action.

Alongside with the provision of reliable anticorrosive coatings, addition of such corrosion inhibitors to the penetrant formulation improves colouring properties of the penetrant.

It is ineffective to introduce the corrosion inhibitor in amounts less than 0.5 mass %, while introduction the inhibitor in amounts over 10.0 mass % is found to be impossible without disturbing the proportions of the components incorporated in the penetrant composition.

The suitable fluorescent dye is 1,8naphthoylene-1 ',2'-benzoimidazole, C18H10N20, molecular mass 270.3, having the following structural formula:

which is a bright greenish yellow crystalline powder having a melting point of from 204 to 207 OC, fluorescent under ultraviolet light in a bright yellowish-green colour (fluorescence maximum at 510 nm).

Suitable solvents for the fluorescent dyes are hydrocarbons taken singly or in combinations and selected from the group of diaryl paraffins having one or more, preferably two or more carbon atoms in the paraffin chain, e.g. ditolyl methane, dicumyl methane, ditolyl ethane, di-meta-xylyl ethane, and ditolyl isobutane.

The solvents that can be used in inspection penetrant formulations include also compounds having condensed benzene rings, e.g. tetrahydronaphthalene (Tetralin), decahydronaphthalene (Decalin), and compound from the terpene group, e.g. turpentine oil.

Ditolyl methane C15H16: an oily liquid with pungent smell, molecular mass of 196.99, density of 0.9825, boiling point of 2920C, melting point of-3200, featuring good adhesive properties, maximum allowable concentration for vapour and aerosol equals to 1.0 mg/m3.

Dicumyl methane C1gH24: a viscous oily liquid with pungent smell, molecular mass of 252.39, boiling point of 3350C, melting point of 2200, density of 0.945, featuring good adhesive properties, maximum allowable concentration for vapour and aerosol equals to 5 mg/m3.

Ditolyl ethane C,6H,8: a colourless liquid with a molecular mass of 210, density of 0.9746, boiling point of 229"C, melting point of -440C, featuring good adhesive properties, maximum allowable concentration for vapour and aerosol equals to 7.2 mg/m3.

Di-meta-xylyl ethane C18H22: a crystalline compound with a molecular mass of 238, melting point of 36.2 C. The melt is a colourless, odourless liquid having a density of 0.9700 at 370C, boiling point of 33000, featuring good adhesive properties, maximum allowable concentration for vapour and aerosol equal to 50 mg"m3.

Dicumyl ethane C20H2s: colourless liquid with a molecular mass of 266, density of 0.9552, boiling point of 31 50C, melting point of 3000, featuring good adhesive properties, maximum allowable concentration for vapour and aerosol equals to 70 mg/m3.

Ditolyl isobutane C,8H22: a colourless liquid with a molecular mass of 238, density of 0.9633, boiling point 3090C, melting point of1 500, featuring good adhesive properties, maximum allowable concentration for vapour and aerosol equals to 70 mg/m3.

1,2,3,4 tetrahydronaphthalene (Tetralin) C,OH,2: a colourless mobile liquid with a molecular mass of 132.22, density of 0.9763, boiling point of 207.5 C, featuring good adhesive properties, maximum allowable concentration in a room of workshop equals to 100 mg/m3.

Decahydronaphthalene (Decalin) C,OH,8: a colourless mobile liquid with a molecular mass of 138.26, density of from 0.8903 to 0.8699, boiling point of 195.7 to 187.30C, melting point of -43.01 to -30A00C, maximum allowable concentration in a workshop room equals to 100 mg/m3.

Turpentine oil or turpentine: a colourless or greenish-yellow mobile liquid having a density of 0.85 to 0.88, boiling point ranging from 155 to 1 8000, maximum allowable concentration in a workshop room equals to 300 mg/m3.

Noteworthy is to mention that the proposed inspection penetrant composition is in no way restricted to the solvents listed hereinabove and that other equivalent solvents can be suitably used for this purpose.

Oxygen-containing organic compounds such as normal butyl alcohol, isobutyl alcohol, normal propyl alcohol, propylene carbonate are suitable solvents for the visible-colour dyes.

Normal butyl alcohol C4HgOH: a colourless liquid having a density of 0.809, boiling point of 117.5 C.

Isobutyl alcohol C4HgOH: a colourless liquid having a density of 0.803 and a boiling point of 1080C.

Normal propyl alcohol C3H,OH: a colourless liquid having a density of 0.804, boiling point of 97.20C.

Propylene carbonate C3H^CO3: an odourless, colourless liquid having a density of 1.2057 and a boiling point of 241.7 OC.

The solvents for the visible-colour dyes as listed above are not meant to exclude the possibilities of using other similar and equivalent solvents.

In the proposed penetrant composition, low molecular aliphatic alcohols may simultaneously perform three functions: those of a solvent for a visible-colour dye, a volatile component for a fluorescent dye solvent, and a surfactant.

The multifunctional effect of the aforesaid alcohols serves to enhance the detectability of inspection penetrants, similar to the effect produced by incorporation of surfactants, resulting in a better penetrability of the penetrant composition into the flaw cavities. This makes it possible to reveal defects present in articles as clearly defined bright indication traces.

Thus, the solvent system for the proposed penetrant composition comprises solvents for the fluorescent dye or their mixture and oxygencontaining organic compounds or their mixtures, used as solvents for the visible-colour dye, said solvents being well miscible.

One class of surfactants that can be suitably used for preparation of inspection penetrants are mixtures of monoalkyl and dialkyl phenol ethers of polyethylene glycol:

where R-alkyl radical containing from 8 to 10 carbon atoms; R,=R or H; n=6-7 or 10-12.

Another class of surfactants that can be used are mixtures of polyethylene glycol ethers of synthetic primary C,0 to C,8 fatty alcohols having the general formula: CnH2+1O(CH2CH2O)H where n+10-18 and m=10.

Introduction of surfactants in the penetrant serves to improve the penetrability thereof into the cavities of defects, thus improving detectability of said penetrant.

The proposed inspection penetrant composition can be prepared in the following manner.

A weighed quantity of a fluorescent dye is dissolved in a calculated quantity of a solvent (or a mixture of solvents) contained in a beaker placed on a water bath, while stirring and heating to 100 C. A weighed quantity of a surfactant is then added under stirring to the resulting solution.

Where corrosion inhibitors are employed, these are to be added to the composition simultaneously with the surfactant.

A visible-colour dye is dissolved in a suitable solvent for said dye without heating or heating on a water bath to a temperature of 50 to 600C.

Next, the resulting solutions of the fluorescent and visible-colour dyes are thoroughly mixed.

The penetrant composition so prepared and allowed to cool to room temperature is tested on the test specimens.

Detection of the surface flaws can be performed using the following techniques.

The liquid penetrant composition is applied to the test surface that has been thoroughly cleaned (washed and dried), so as to aliow the cavities of the defects to be fiiled.

Excess liquid dye penetrant composition is removed from the test surface by using a cleaning liquid, such as surfactant dissolved in water, without dislodging such penetrant from the defects. The test surface is rinsed thereafter with a warm water spray (water temperature about 300 C, washing time 1 to 3 minutes).

Following the washing step, the test surface background is checked to make sure that there is no fluorescence under ultraviolet light and colouration under while light, showing on the test surface, whereupon, the test surface is dried by a blast of room-temperature air or wiped dry with a clean piece of fabric.

A developer composition is then applied to the test surface, the developer being permitted to dwell over the test surface for a period of about 3 to 5 minutes to cause the penetrant retained in the cracks or surface flaws to be drawn up out of the surface defects by capillary action.

Then, the test surface is inspected for flaws under ultraviolet and white lighting conditions. An ultraviolet radiation source with a wavelength range of 315 to 400 mm is used.

Under ultraviolet light the defects are revealed as fluorescent indication traces of two basic colours.

Depending on the amount of the fluorescent dye incorporated into the penetrant composition and on the washing time (to remove excess penetrant from the test surface), the defects over 0.3-0.4 mm in depth are developed as fluorescent indication traces coloured reddish violet or red, pink of various intensity, pink white.

The defects less than 0.3-0.4 mm in depth are developed under ultraviolet light as fluorescent indication traces coloured within the range from bluish to greenish.

Under white light, the defects over 0.3-0.4 mm in depth are developed as reddish violet or red dye indication traces.

The proposed penetrant compositions are tested by application to the test specimens with a predetermined number of defects in a manner described hereinabove.

The test results provide a measure of reproducibility of flaw indication obtainable with the penetrant composition tested on the test specimens and enable an evaluation of the quality of the inspection penetrant tested.

Test results are evaluated using the following evaluation technique.

First, test results are assessed based on counting a number of defects revealed under white light as indication traces coloured reddish violet or red. These indication traces correspond to defects over 0.3-0.4 mm in depth.

Next, a number of defects revealed under ultraviolet light as fluorescent indication traces coloured in the range from reddish violet or red, pink of various intensity to pink white, is counted.

Then a comparative evaluation of the indication traces corresponding to defects over 0.3-0.4 mm in depth and revealed in the visible and ultraviolet regions is sequently performed in terms of number of defects revealed and of detection efficiency.

The same evaluation is performed for defects less than 0.3-0.4 mm in depth, developed under ultraviolet light as bluish or greenish fluorescent indication traces.

Thanks to the visible-colour dye incorporated in the penetrant formulation, the possibility exists of differentiating the revealed defects with respect to depth, and of using the penetrant both for fluorescent and visible-colour methods of flaw detection.

Differentiation of the revealed defects with respect to depth is an essential feature of the proposed penetrant, which permits to judge of the defect depth at a first checkout operation, thus eliminating the need for trimming and repeat check-out operations. If the depth of the defects in the workpiece lies within the limits of the dimensional tolerances the shallow defects will be removed by the subsequent mechanical working. Thus, the productional cycle is reduced.

What is more, the proposed inspection penetrant compositions feature low toxicity and low fire hazard propensity.

High quality compositions with a good balance of all properties essential for flaw detection by capillary methods have been obtained by incorporation of the fluorescent dye solvents featuring high adhesive properties and low vapour pressure, as well as by use of suitable surfactants and corrosion inhibitors and by application of two kinds of indication dyes soluble in different solvents and featuring high miscibility.

Thus, the balance of all essential properties inherent in the proposed penetrant compositions used for capillary flaw detection is considerably superior to that of the known penetrant compositions.

The following examples serve to illustrate but are not limitive of the benefits and advantages obtained by practice of the present invention.

Example 1 An inspection penetrant composition was composed of the following components in percent by mass: fluorescent dye 0.2 surfactant (a mixture of mono and dialkyl phenyl polyethylene glycol ethers) 2.0 ditolyl ethane 63.0 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 0.8 n-butyl alcohol 34.0 0.2 g of the fluorescent dye was dissolved in 64.6 ml of ditolyl ethane contained in a beaker, while stirring and heating the contents of 1000C on a water bath. The surfactant in the amount of 2.0 g was then added to the solution and thoroughly mixed in. 0.8 g of the visible-colour dye was dissolved under stirring in 42.0 ml of nbutyl alcohol contained in a beaker under room temperature. The resulting solutions of the fluorescent and visible-colour dyes were mixed and thoroughly stirred.

The inspection penetrant composition so prepared and allowed to cool to room temperature was tested on the test specimens.

For this purpose, the dye penetrant composition was applied to the test surface previously cleaned (washed and dried), so as to allow the cavities of the cracks and defects to be filled.

Then excess liquid dye penetrant composition was removed from the test surface without removing such penetrant from the cracks and defects. To accomplish this, the test surface was rinsed in a spray of warm water (water temperature about 300C, washing time 1 to 3 minutes).

Following the water washing step, the test surface background was checked to make sure that there was no fluorescence under ultraviolet light or coloration under white light, showing on the test surface.

After the background checking step, the test surface was dried by a blast of room temperature air or wiped dry with a clean piece of fabric, whereupon a developer composition was applied to the clean and dry test surface. On application of the developer coating and after allowing a dwell time of 3 to 5 minutes (for the developer to draw up the residual indicator dye out of the surface cracks and flaws), the test surface was inspected for flaw detection under ultraviolet light and under white light.

Test results were evaluated using the following evaluation technique.

Evaluation of test results was first performed based on the number of defects revealed under white light as reddish violet or red indication traces, said coloration of the indication traces indicating conclusively that the revealed defects are over 0.3-0.4 mm in depth.

Next, the number of defects revealed under ultraviolet light as fluorescent indication traces coloured in the range from reddish violet or red, pink of various intensity to pink white, was counted, such coloration of the fluorescent indication traces corresponding to defects over 0.3-0.4 mm in depth.

Then a comparative evaluation of the indication traces corresponding to defects over 0.34.4 mm in depth and revealed in the visible and ultraviolet regions is sequently performed in terms of number of defects revealed and detection efficiency.

The same evaluation was performed for defects less than 0.3-0.4 mm in depth developed under ultraviolet light as bluish or greenish fluorescent indication traces.

Test results: All of the defects present in the test specimens had been revealed.

Defects over 0.3-0.4 mm in depth were developed as pink fluorescent indication traces under ultraviolet light and as reddish violet dye indication traces under white light.

Defects less than 0.3--0.4 mm in depth were developed under ultraviolet light as bluish fluorescent indication traces.

All of the defect indication traces were found well defined and good.

Example 2 An inspection penetrant composition was composed of the following components in percent by mass: fluorescent dye 0.5 surfactant (a mixture of mono and dialkyl phenyl polyethylene glycol ethers) 3.0 ditolyl ethane 62.6 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 0.9 n-butyl alcohol 33.0 The procedures for preparation and testing of the inspection penetrant of above composition were similar to those of Example 1.

Test results: All of the defects present in the test specimens had been revealed.

Colouration of the indication traces depending on the defect deptn under ultraviolet and white lighting conditions was similar to that of Example 1.

The defect indication traces were good and well defined.

Example 3 An inspection penetrant composition comprising in percent by mass: fluorescent dye 1.0 surfactant (a mixture of mono and dialkyl phenyl polyethylene glycol ethers) 4.0 tetrahydronaphthalene 24.0 decahydronaphthalene 30.0 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 1.0 propylene carbonate 40.0 was prepared by dissolving under stirring 1.0 g of fluorescent dye in 24.6 ml of tetrahydronaphthalene and 33.7 ml of decahydronaphthalene contained in a beaker heated to a temperature of 1000C on a water bath, adding afterwards 4.0 g of surfactant. The resulting mixture was thoroughly stirred.

0.1 g of the visible-colour dye was dissolved with stirring and heating to 50-600C on a water bath in 33.2 ml of propylene carbonate contained in a beaker.

The resultant solutions were mixed and thoroughly stirred. The penetrant composition so obtained and allowed to cool to room temperature was tested in a manner described in Example 1.

Test results: All of the defects present in the test specimens had been revealed.

Defects less than 0.3-0.4 mm in depth were developed under white light as reddish violet dye indication traces, and under ultraviolet light as pink fluorescent indication traces Defects less than 0.3-0.4 mm in depth were developed under ultraviolet light as bluish green fluorescent indication traces.

The defect indication traces were well defined and good.

Example 4 An inspection penetrant was composed of the following components taken in percent by mass: fluorescent dye 2.0 surfactant (a mixture of mono and dialkyl phenyl polyethylene glycol ethers) 5.0 tetrahydronaphthalene 33.3 decahydronaphthalene 5.0 tetraethyi diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 1.4 propylene carbonate 53.3 The procedure for preparation of the penetrant composition was similar to that described in Example 3.

The testing procedure was similar to that of Example 1.

Test results: All of the defects present in the test specimens had been revealed.

Defects over 0.3--0.4 mm in depth were revealed under white light as dye indication traces coloured reddish violet, and under ultraviolet light as bright pink fluorescent indication traces.

Defects less than 0.3-0.4 mm in depth were revealed under ultraviolet light as bright bluish green traces.

The defect indication traces were well defined and good.

Example 5 An inspection penetrant was composed of the following components taken in percent by mass: fluorescent dye 4.0 surfactant (a mixture of mono and dialkyl phenyl polyethylene glycol ethers) 2.0 tetrahydronaphthalene 63.0 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 0.8 propylene carbonate 30.2 The procedure for preparation of the inspection penetrant was similar to that of Example 3.

The penetrant of above composition was tested in a manner described in Example 1.

Test results: All of the defects present in the test specimens had been revealed.

Defects over 0.3--0.4 mm in depth were revealed under white light as dye indication traces coloured reddish violet, and under ultraviolet light as fluorescent indication traces coloured bright pink white.

Defects less than 0.3-0.4 mm in depth were revealed under ultraviolet light as fluorescent indication traces coloured bright greenish.

The defect indication traces were well defined and good.

Example 6 An inspection penetrant was composed of the following components taken in percent by mass: fluorescent dye 2.0 surfactant (a mixture of mono and dialkyl phenyl polyethylene glycol ethers) 6.0 tetrahydronaphthalene 36.0 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 1.5 propylene carbonate 54.5 The procedure for preparation of the inspection penetrant of above composition was similar to that described in Example 3.

The testing procedure was similar to that of Example 1.

Test results: All of the defects present in the test specimens had been revealed.

Defects over 0.3--0.4 mm in depth were revealed under white light as indication traces coloured reddish violet, and under ultraviolet light as bright fluorescent indication traces coloured reddish violet.

Defects less than 0.3-0.4 mm in depth were revealed under ultraviolet light as bright fluorescent indication traces coloured greenish blue.

The defect indication traces were good and well defined.

Example 7 An inspection penetrant was composed of the following components taken in percent by mass: fluorescent dye 0.5 surfactant (a mixture of polyethylene glycol ethers of synthetic primary C,O to Cis fatty alcohols) 8.0 dicumyl methane 30.0 di-meta-xylyl ethane 25.0 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 0.8 n-butyl alcohol 35.7 The penetrant of above composition was prepared by dissolving with stirring 0.5 g of fluorescent dye in a beaker containing 31.7 ml of dicumyl methane and 25.0 g of di-meta-xyiyl ethane and placed on a water bath to be heated to a temperature of 1000C. Then 8.0 g of the surfactant was added. The resulting mixture of ingredients was stirred thoroughly.

0.8 g of the visible-colour dye was dissolved in 44.1 ml of n-butyl alcohol without heating.

The resulting solutions of the fluorescent and visible-colour dyes were mixed and thoroughly stirred.

The penetrant composition thus obtained was allowed to cool to room temperature and then tested in a manner similar to the procedure described in Example 1.

Test results: All of the defects present in the test specimens had been revealed.

Defects over 0.3-0.4 mm in depth were revealed under white light as reddish violet dye indication traces, and under ultraviolet light as pink fluorescent indication traces.

Defects less than 0.3-0.4 mm in depth were revealed under ultraviolet light as bluish fluorescent indication traces.

All the defect indication traces were good and well defined.

Example 8 An inspection penetrant was composed of the following components taken in percent by mass: fluorescent dye 0.5 surfactant (a mixture of polyethylene glycol ethers of synthetic primary C0 to C,8 fatty alcohols) 9.0 dicumyl methane 30.0 dicumyl ethane 24.0 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 0.8 n-butyl alcohol 15.7 n-propyl alcohol 20.0 The procedure for preparation of the inspection penetrant of above composition was similar to that described in Example 7, but with the visiblecolour dye dissolved in a mixture of n-butyl alcohol and n-propyl alcohol.

The test procedure was similar to that described in Example 1.

Test results: All of the defects present in the test specimens had been revealed.

The defect indication traces were similar to those described in Example 7.

Example 9 An inspection penetrant was composed of the following components taken in percent by mass: fluorescent dye 0.5 surfactant (a mixture of polyethylene glycol ethers of synthetic primary C,0 to C,8 fatty alcohols) 10.0 dicumyl methane 20.0 ditolyl isobutane 33.0 tetraethyi diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 0.8 n-butyl alcohol 1 5.7 isobutyl alcohol 20.0 The procedure for preparation of the inspection penetrant of above composition was similar to that of Example 7, but with the visible-colour dye dissolved in a mixture of n-butyl alcohol and isobutyl alcohol.

The testing procedure was similar to that of Example 1.

Test results: All of the defects present in the test specimens had been revealed. The defect indication traces were similar to those described in Example 7.

Example 10 An inspection penetrant was composed of the following components taken in percent by mass: fluorescent dye 0.5 di-meta-xylyl ethane 33.0 ditolyl methane 30.0 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 0.8 n-butyl alcohol 33.7 surfactant (a mixture of mono and dialkyl phenyl polyethylene glycol ethers) 2.0 The penetrant of above composition was prepared by dissolving 0.5 g of the fluorescent dye in 30.5 ml of ditolyl methane and 33.0 g of di-meta-xylyl ethane, while stirring and heating to 1000C on a water bath, whereupon 2.0 g of the surfactant was added to the solutions. 0.8 g of the visible-coiour dye was dissolved in 41.6 ml of n-butyl alcohol at room temperature. The resulting solutions were mixed and thoroughly stirred.

The penetrant composition so obtained and allowed to cool to room temperature was tested in a manner similar to that described in Example 1.

Test results: All of the defects present in the test specimens had been revealed.

Defects over 0.3--0.4 mm in depth were revealed as reddish violet dye indication traces under white light, and under ultraviolet light as fluorescent indication traces coloured pink.

Defects less than 0.3--0.4 mm in depth were revealed under ultraviolet light as fluorescent indication traces coloured bluish.

The defect indication traces were good and well defined.

Example 11 An inspection penetrant was composed of the following components taken in percent by mass: fluorescent dye 0.5 di-meta-xylyl ethane 30.0 ditolyl methane 33.0 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-coloured dye 0.8 n-butyl alcohol 20.7 n-propyl alcohol 10.0 surfactant (a mixture of mono and dialkyl phenyl polyethylene glycol ethers) 5.0 The procedure for preparation of the inspection penetrant was similar to that described in Example 10, but with the visible-colour dye dissolved in a mixture of n-butyl alcohol and npropyl alcohol.

The testing procedure was similar to that of Example 1.

Test results: All of the defects present in the test specimens had been revealed, the defect indication traces being similar to those described in Example 10.

Example 12 An inspection penetrant was composed of the following components taken in percent by mass: fluorescent dye 0.5 di-meta-xylyl ethane 28.5 ditolyl methane 30.0 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 0.8 n-butyl alcohol 20.2 isobutyl alcohol 10.0 surfactant (a mixture of mono and dialkyl phenyl polyethylene glycol ethers) 10.0 The procedure for preparation of the inspection penetrant composition was similar to that described in Example 20, but with the visiblecolour dye dissolved in a mixture of n-butyl alcohol and isobutyl alcohol.

The testing procedure was similar to that described in Example 1.

Test results: All of the defects present in the test specimens had been revealed, the defect indication traces being similar to those described in Example 10.

Example 13 An inspection penetrant was prepared, comprising in percent by mass: fluorescent dye 1.0 ditolyl ethane 63.0 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 0.8 n-butyl alcohol 33.2 surfactant (a mixture of polyethylene glycol ethers of synthetic primary C,0 to C,8 fatty alcohols) 2.0 The procedure for preparation of the inspection penetrant composition was similar to that described in Example 10.

The testing procedure was similar to that of Example 1.

Test results: All of the defects present in the test specimens had been revealed.

Defects over 0.3-0.4 mm in depth were revealed as reddish violet dye indication traces under white light, and as pink-white fluorescent indication traces under ultraviolet light.

Defects less than 0.3-0.4 mm in depth were revealed under ultraviolet light as bluish fluorescent indication traces.

The defect indication traces were good and well defined.

Example 14 An inspection penetrant composition was prepared, comprising in percent by mass: fluorescent dye 1.2 ditolyl ethane 58.4 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 1.0 n-butyl alcohol 36.4 surfactant (a mixture of polyethylene glycol ethers of synthetic primary C,O to C,8 fatty alcohols) 3.0 The procedure for preparation of the inspection penetrant composition was similar to that described in Example 10.

The testing procedure was similar to that of Example 1.

Test results: All of the defects present in the test specimens had been revealed, the defect indication traces being in similar to those described in Example 13.

Example 15 An inspection penetrant was composed of the following components taken in percent by mass: fluorescent dye 0.1 dicumyl ethane 63.0 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 0.8 n-butyl alcohol 22.1 isobutyl alcohol 10.0 surfactant (a mixture of polyethylene glycol ethers of synthetic primary C10 to C18 fatty alcohols) 4.0 0.1 g of the fluorescent dye was dissolved in 66.1 ml of dicumyl ethane contained in a beaker, while stirring and heating the contents to 1000C on a water bath. The surfactant in the amount of 4.0 g was then added to the solution.

0.8 g of the visible-colour dye was dissolved in a mixture of 27.3 ml of n-butyl alcohol and 1-2.5 ml of iso-butyl alcohol without heating.

The resulting solutions of the fluorescent and visible-colour dyes were mixed and thoroughly stirred. The inspection penetrant composition so prepared and allowed to cool to room temperature was tested in a manner described in Example 1.

Test results: All of the defects present in the test specimens had been revealed.

Defects over 0.3--0.4 mm in depth were revealed under white light as reddish violet dye indication traces and under ultraviolet light as fluorescent indication traces coloured reddish pink.

Defects less than 0.3-0.4 mm in depth were revealed under ultraviolet light as bluish fluorescent indication traces.

The defect indication traces were well defined and good.

Example 16 An inspection penetrant composition was prepared, comprising in percent by mass: fluorescent dye 0.2 dicumyl ethane 53.8 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 1.0 n-butyl alcohol 20.0 isobuty alcohol 20.0 surfactant (a mixture of polyethylene glycol ethers of synthetic primary C10 to C18 fatty alcohols) 5.0 The procedure for preparation of the inspection penetrant composition was similar to that of Example 15.

The penetrant composition was tested on the test specimens in a manner similar to the procedure described in Example 1.

Test results: All of the defects present in the test specimens had been revealed.

Defects over 0.3-0.4 mm in depth were revealed under white light as reddish violet dye indication traces and under ultraviolet light as fluorescent indication traces coloured reddish pink.

Defects less than 0.3-0.4 mm in depth were revealed under ultraviolet light as bluish fluorescent indication traces.

The defect indication traces were well defined and good.

Example 17 An inspection penetrant was composed of the following components taken in percent by mass: fluorescent dye 0.2 di-meta-xylyl ethane 63.0 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 0.8 n-butyl alcohol 34.0 surfactant (a mixture of polyethylene glycol ethers of synthetic primary C10 to C18 fatty alcohols) 2.0 0.2 g of the fluorescent dye was dissolved in 63.0 g of di-meta-xylyl ethane with stirring and heating to 1000C on a water bath, adding afterwards 2.0 g of the surfactant. The resulting solution was thoroughly stirred.

0.8 g of the visible-colour dye was dissolved in 42.0 ml of n-butyl alcohol without heating.

The solutions of the fluorescent and visiblecolour dyes were mixed and thoroughly stirred.

The resulting penetrant composition allowed to cool to room temperature was tested in a manner similar to the procedure described in Example 1.

Test results: All of the defects present in the test specimens had been revealed.

Defects over 0.3-0.4 mm in d.epth were revealed under white light as reddish violet dye indication traces and under ultraviolet light as fluorescent indication traces coloured pink.

Defects less than 0.3-0.4 mm in depth were revealed under ultraviolet light as bluish fluorescent indication traces.

The defect indication traces were well defined and good.

Example 18 An inspection penetrant composition was prepared, comprising in percent by mass: fluorescent dye 0.25 di-meta-xylyl ethane 59.85 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 0.90 n-butyl alcohol 36.00 surfactant (a mixture of polyethylene glycol ethers of synthetic primary C10 to C18 fatty alcohols) 3.00 The procedure for preparation of the inspection penetrant of above compositions was similar to that described in Example 1 7.

The testing procedure was similar to that of Example 1.

Test results: All of the defects present in the test specimens had been revealed.

Defects over 0.3-0.4 mm in depth were revealed under white light as reddish violet dye indication traces and under ultraviolet light fluorescent indication traces coloured reddish pink.

Defects less than 0.3-0.4 mm in depth were revealed under ultraviolet light as bluish fluorescent indication traces.

The defect indication traces were good and well defined.

Example 19 An inspection penetrant was composed of the following components taken in percent by mass: fluorescent dye 1.5 surfactant (a mixture of mono and dialkyl phenyl polyethylene glycol ethers) 5.0 tetrahydronaphthalene 52.7 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 0.8 propylene carbonate 40.0 The penetrant composition was prepared in the following manner.

1.5 g of the fluorescent dye were dissolved in 54.0 ml of tetrahydronaphthalene, while stirring and heating to 1000C on a water bath, adding afterwards 5.0 g of the surfactant under stirring.

0.8 g of the visible-colour dye was dissolved in 33.2 ml of propylene carbonate heated to 50600C on a water bath.

The resulting solutions of the fluorescent and visible-colour dyes were mixed and thoroughly stirred.

The penetrant composition so prepared and allowed to cool to room temperature was tested in a manner similar to the procedure described in Example 1.

Test results: All of the defects present in the test specimens had been revealed.

Defects over 0.3-0.4 mm in depth were revealed under white light as dye indication traces coloured reddish violet and under ultraviolet light as bright pink-white fluorescent indication traces.

Defects less than 0.3--0.4 mm in depth were revealed under ultraviolet light as bright greenish fluorescent indication traces.

The defect indication traces were well defined and good.

Example 20 An inspection penetrant composition was prepared, comprising in percent by mass: fluorescent dye 2.0 tetrahydronaphthalene 49.1 surfactant (a mixture of mono and dialkyl phenyl polyethylene glycol ethers) 3.0 tetraethyl-diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 0.9 propylene carbonate 45.0 The procedure for preparation of the penetrant composition was similar to that of Example 1 9.

The testing procedure was similar to the procedure described in Example 1.

The test results were the same as in Example 19.

Example 21 An inspection penetrant composition was prepared, comprising in percent by mass: fluorescent dye 2.7 tetrahydronaphthalene 46.3 surfactant (a mixture of mono and dialkyl phenyl polyethylene glycol ethers 2.0 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 1.0 propylene carbonate 48.0 The penetrant composition was prepared in a manner similar to the procedure described in Example 19.

The testing procedure was similar to that of Example 1.

The test results were the same as in Example 19.

Example 22 An inspection penetrant composition comprising percent by mass: fluorescent dye 0.2 di-meta-xylyl ethane 62.5 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 0.8 surfactant (a mixture of polyethylene glycol ethers of synthetic primary C10 to C18 fatty alcohols) 3.0 n-butyl alcohol 32.5 corrosion-inhibitor (a mixture of cyclohexylamine and fatty acids) 1.0 was prepared in the following manner.

0.2 g of the fluorescent dye was dissolved in 62.5 g of melted di-meta xylyl ethane, while stirring and heating to 1000C on a water bath, adding afterwards 3.0 g of the surfactant and 1.0 g of the corrosion inhibitor. The resulting mixture was thoroughly stirred to obtain a homogeneous solution.

0.8 g of the visible-colour dye was dissolved in 40.3 ml of n-butyl alcohol without heating.

The resulting solutions of the fluorescent and visible-colour dyes were mixed and thoroughly stirred.

The inspection penetrant composition so obtained and allowed to cool to room temperature was tested in a manner similar to the procedure described in Example 1.

Test results: All of the defects present in the test specimens had been revealed.

Defects over 0.3-0.4 mm in depth were revealed under white light as dye indication traces coloured reddish violet, and under ultraviolet light as pink fluorescent indication traces.

Defects less than 0.3-0.4 mm in depth were revealed under ultraviolet light as bluish fluorescent indication traces.

The defect indication traces were well defined and good.

Example 23 An inspection penetrant composition was prepared, comprising in percent by mass: fluorescent dye 0.25 di-meta-xylyl ethane 60.00 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 0.90 n-butyl alcohol 32.85 surfactant (a mixture of polyethylene glycol ethers of synthetic primary C10 to C18 fatty alcohols 4.00 corrosion inhibitor (a mixture of cylohexylamine and fatty acids) 2.00 The procedure for preparation of the penetrant composition was similar to that described in Example 22.

The testing procedure was similar to that of Example 1.

The test results were the same as in Example 22.

Example 24 An inspection penetrant composition was prepared, comprising in percent by mass: fluorescent dye 0.3 di-meta-xylyl ethane 53.7 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible dye 1.0 n-butyl alcohol 37.0 surfactant (a mixture of polyethylene glycol ethers of synthetic primary C,O to C,8 fatty alcohols) 5.0 corrosion inhibitor (a mixture of cyclohexylamine and fatty acids) 3.0 The inspection penetrant composition was prepared in a manner described in Example 22.

The testing procedure was similar to that of Example 1.

The test results were the same as in Example 22.

Example 25 An inspection penetrant composition comprising in percent by mass: fluorescent dye 0.3 ditolyl isobutane 62.5 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 0.8 n-butyl alcohol 30.4 surfactant (a mixture of polyethylene glycol ethers of synthetic primary C10 to C18 fatty alcohols) 5.0 corrosion inhibitor (a mixture of cyclohexylamine and fatty acids) 1.0 was prepared in the following manner.

0.2 g of the fluorescent dye was dissolved, while stirring and heating to 1000C on a water bath, in 65.5 ml of ditolyl isobutane, adding afterwards 5.0 g of the surfactant and 1.0 g of the corrosion inhibitor. The resulting mixture was then thoroughly stirred.

0.8g of the visible-colour dye was dissolved in 37.8 ml of n-butyl alcohol without heating.

The resulting solutions of the fluorescent and visible-colour dyes were mixed and thoroughly stirred. The penetrant composition so obtained and allowed to cool to room temperature was tested in a manner similar to the procedure described in Example 1.

Test results: All of the defects present in the test specimens had been revealed.

Defects over 0.3-0.4 mm in depth were revealed under white light as dye indication traces coloured reddish violet and under ultraviolet light as pink fluorescent indication traces.

Defects less than 0.3--0.4 mm in depth were revealed under ultraviolet light as bluish fluorescent indication traces.

The defect indication traces were good and well defined.

Example 26 An inspection penetrant composition was prepared, comprising in percent by mass: fluorescent dye 0.25 ditolyl isobutane 56.85 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 0.90 n-butyl alcohol 32.50 surfactant (a mixture of polyethylene glycol ethers of synthetic primary C10 to C18 fatty alcohols) 7.50 corrosion inhibitor (a mixture of cyclohexylamine and fatty acids) 2.0 The procedure for preparation of the inspection penetrant of above composition was similar to that described in Example 25.

All testing operations were similar to those described in Example 1.

The test results were the same as those cited in Example 25.

Example 27 An inspection penetrant composition was prepared, comprising in percent by mass: fluorescent dye 0.2 ditolyl isobutane 48.8 tetraethyl diamine-o-carboxy phenyl xanthenyl chloride visible-colour dye 1.0 n-butyl alcohol 37.0 surfactant (a mixture of polyethylene glycol ethers of synthetic primary C10 to C18 fatty alcohols) 10.0 corrosion inhibitor (a mixture of cyclohexylamine and fatty acids) 3.0 The procedure for preparation of the inspection penetrant composition was similar to that described in Example 25.

The testing procedure was similar to that of Example 1.

The test results were the same as those cited in Example 25.

Example 28 An inspection penetrant composition comprising in percent by mass: fluorescent dye 0.4 decahydronaphthalene 53.5 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 0.8 isobutyl alcohol 30.3 surfactant (a mixture of mono and dialkyl phenyl polyethylene glycol ethers) 5.0 corrosion inhibitor (polyethylene glycol, molecular mass 400) 10.0 was prepared in the following manner.

0.4 g of the fluorescent dye was dissolved, while stirring and heating on a water bath to 1000C, in 60.4 ml of decahydronaphthalene, adding afterwards 5.0 g of the surfactant and 10.0 g of the corrosion inhibitor. The resulting mixture was thoroughly stirred.

0.8 g of the visible-colour dye was dissolved in 37.3 ml of isobutyl alcohol without heating.

The fluorescent dye solution was allowed to cool to room temperature and was then mixed with the visible colour dye solution. The resulting mixture of ingredients was stirred thoroughly to a homogeneous solution.

The penetrant composition so obtained was tested by application over the test specimens.

The testing procedures was similar to that described in Example 1.

Test results: All of the defects present in the test specimens had been revealed.

Defects over 0.3-0.4 mm in depth were revealed under white light as reddish violet dye indication traces and under ultraviolet light as pink fluorescent indication traces.

Defects less than 0.3-0.4 mm in depth were revealed under ultraviolet light as bluish fluorescent indication traces.

The defect indication traces were evaluated as good and well defined.

Example 29 An inspection penetrant composition was prepared, comprising in percent by mass: fluorescent dye 0.5 decahydronaphthalene 60.0 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 0.9 isobutyl alcohol 31.5 surfactant (a mixture of mono and dialkyl phenyl polyethylene glycol ethers) 3.0 corrosion inhibitor (polyethylene glycol, molecular mass 400) 4.0 The procedure for preparation of said penetrant composition was similar to that described in Example 28.

All testing operations were similar to those described in Example 1.

The test results were the same as those cited in Example 28.

Example 30 An inspection penetrant composition was prepared, comprising in percent by mass: fluorescent dye 0.6 decahydronaphthalene 62.0 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 1.0 isobutyl alcohol 33.9 surfactant (a mixture of mono and dialkyl phenyl polyethylene glycol ethers) 2.0 corrosion inhibitor (polyethylene glycol, moleculas mass 400) 0.5 The procedure for preparation of said inspection penetrant composition was similar to that of Example 28.

All testing operations were similar to those described in Example 1.

The test results were the same as those described in Example 28.

Example 31 An inspection penetrant composition comprising in percent by mass: fluorescent dye 0.5 tetrahydronaphthalene 10.0 turpentine 52.5 tetraethyi diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 0.8 n-propyl alcohol 30.2 surfactant (a mixture of mono and dialkyl phenyl polyethylene glycol ethers) 3.0 corrosion inhibitor (aliphatic alkyl amines with C15 to C18 alkyl chain lengths) 3.0 was prepared in the following manner.

0.5 g of the fluorescent dye was dissolved in a mixture of 10.2 ml of tetrahydronaphthalene and 61.0 mi of turpentine, while stirring and heating to 1000C on a water bath, adding afterwards 3.0g of the surfactant and 3.0 g of the corrosion inhibitor. The total was thoroughly mixed up until a homogeneous solution.

0.8 g of the visible-colour dye was dissolved in 37.3 ml of n-propyl alcohol without heating.

Then the fluorescent dye solution allowed to cool to room temperature was mixed with the visible-colour dye solution and thoroughly stirred until a homogeneous solution was obtained.

The penetrant composition so prepared was tested on the test specimens in a manner similar to the testing procedure described in Example 1.

Test results: All of the defects present in the test specimens had been revealed.

Defects over 0.3-0.4 mm in depth were revealed under white light as dye indication traces coloured reddish violet, and under ultraviolet light as pink fluorescent indication traces.

Defects less than 0.3-0.4 mm in depth were revealed under ultraviolet light as bluish fluorescent indication traces.

Defect indication traces were evaluated as good and well defined.

Example 32 An inspection penetrant composition was prepared, comprising in percent by mass: fluorescent dye 0.6 tetrahydronaphthalene 10.0 turpentine 47.7 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 0.9 n-propyl alcohol 32.8 surfactant (a mixture of mono and dialkyl phenyl polyethylene glycol ethers) 4.0 corrosion inhibitor (aliphatic alkyl amines with C15 to C18 alkyl chain lengths) 4.0 The procedure for preparation of said penetrant composition was similar to that described in Example 31.

The penetrant composition was tested in a manner similar to the testing procedure described in Example 1.

The test results were the same as those cited in Example 31.

Example 33 An inspection penetrant composition was prepared, comprising in percent by mass: fluorescent dye 0.7 tetrahydronaphthalene 10.0 turpentine 43.3 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 1.0 n-propyl alcohol 35.0 surfactant (a mixture of mono and dialkyl phenyl polyethylene glycol ethers) 5.0 corrosion inhibitor (aliphatic alkyl amines with C18 to C18 alkyl chain lengths) 5.0 The procedure for preparation of said inspection penetrant composition was similar to that of Example 31.

The testing procedure was similar to that described in Example 1.

The test results were the same as those cited in Example 31.

Example 34 An inspection penetrant composition comprising in percent by mass: fluorescent dye 0.5 tetrahydronaphthalene 8.0 turpentine 1 9.9 3-amino-6-dimethylamino-2 methyl phanazine hydro chloride visible-colour dye 1.5 n-propyl alcohol 60.5 surfactant (a mixture of mono and dialkyl phenyl polyethylene glycol ethers) 9.6 was prepared in the following manner.

0.5 g of the fluorescent dye was dissolved in 8.1 ml of tetrahydronaphthalene and 23.0 ml of turpentine, while stirring and heating to 1000C on a water bath, adding afterwards 9.6 g of the surfactant. The resulting mixture was thoroughly mixed until a homogeneous solution was obtained.

1.5 g of the visible-colour dye were dissolved in 75.20 ml of n-propyl alcohol. Then the resulting solutions of the fluorescent dye and the visiblecolour dye taken at room temperature were mixed and thoroughly stirred.

The penetrant composition so obtained was tested on the test specimens in a planar similar to that described in Example 1.

Test results: All of the defects present in the test specimens had been revealed.

Defects over 0.3-0.4 mm in depth were developed under white light as indication traces coloured red and under ultraviolet light as bright red fluorescent indication traces.

Defects less than 0.3-0:4 mm in depth were developed under ultraviolet light as bluish fluorescent indication traces.

The defects indication traces were evaluated as good and well defined.

Example 35 An inspection penetrant composition was prepared, comprising in percent by mass: fluorescent dye 0.6 tetrahydronaphthalene 10.0 turpentine 53.0 3-amino-6-dimethylamino-2 methyl phenazine hydrochloride visible-colour dye 0.8 n-propyl alcohol 32.6 surfactant (a mixture of mono and dialkyl phenyl polyethylene glycol ethers) 3.0 The procedure for preparation of the inspection penetrant of above composition was similar to that described in Example 34.

The penetrant composition was tested in a manner similar to that described in Example 1.

Test results: All of the defects present in the test specimens had been revealed.

Defects over 0.3---0.4 mm in depth were revealed under white light as red dye indication traces and under ultraviolet light as red fluorescent indication traces.

Defects less than 0.3-0.4 mm in depth were revealed under ultraviolet light as bluish fluorescent indication traces.

The detect indication traces were evaluated as good and well defined.

Example 36 An inspection penetrant composition was prepared, comprising in percent by mass: fluorescent dye 0.7 tetrahydronaphthalene 12.0 turpentine 46.4 3-amino-6-dimethylamino-2 methyl phenazine hydrochloride visible-colour dye 0.9 n-propyl alcohol 35.0 surfactant (a mixture of mono and dialkyl phenyl polyethylene glycol ethers) 5.0 The above penetrant composition was prepared essentially as described in Example 34.

The testing procedure for said composition was similar to that described in Example 1.

Test results: All of the defects present in the test specimens had been revealed and differentiated with respect to depth under ultraviolet and white lighting conditions.

Defects over 0.3---0.4 mm in depth were developed under white light as red-coloured indication traces and under ultraviolet light as red fluorescent indication traces.

Defects less than 0.3-0.4 mm in depth were developed under ultraviolet light as bluish fluorescent indication traces.

The defect indication traces were evaluated as good and well defined.

Example 37 An inspection penetrant composition comprising in percent by mass: fluorescent dye 0.5 ditolyl methane 40.1 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 1.0 n-butyl alcohol 50.4 surfactant (a mixture of mono and dialkyl phenyl polyethylene glycol ethers) 5.0 corrosion inhibitor (polyethylene glycol, molecular mass 300) 3.0 was prepared in a manner decribed hereinbelow.

0.5 g of the fluorescent dye was dissolved in 40.8 ml of ditolyl methane, while stirring and - heating to 1000C on a water bath, adding afterwards 5.0 g of the surfactant and 3.0 g of the corrosion inhibitor, the total being thoroughly mixed.

1.0 g of the visible-colour dye was dissolved in 62.3 ml of n-butyl alcohol without heating.

The fluorescent dye solution so obtained and allowed to cool to room temperature was thoroughly mixed with the visible-colour dye solution. The resulting penetrant composition was tested on the test specimens in a manner similar to that described in Example 1.

Test results: All of the defects present in the test specimens had been revealed.

Defects over 0.3-0.4 mm in depth were revealed under white light as reddish violet dye indication traces and under ultraviolet light as pink fluorescent indication traces.

Defects less than 0.3-0.4 mm in depth were revealed under ultraviolet light as bluish fluorescent indication traces.

The defect indication traces were evaluated as good and well defined.

Example 38 An inspection penetrant composition was prepared, comprising in percent by mass: fluorescent dye 0.6 ditolyl methane 46.0 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride- visible-colour dye 0.9 n-butyl alcohol 45.0 surfactant (a mixture of mono and dialkyl phenyl polyethylene glycol ethers) 7.0 corrosion inhibitor (polyethylene glycol, molecular mass 1,500) 0.5 The above penetrant composition was prepared essentially as described in Example 37.

The testing procedure for said penetrant composition was similar to that described in Example 1.

Test results: All of the defects present in the test specimens had been revealed said differentiated with respect to depth.

The defect indication traces were the same as those described in Example 37.

Example 39 An inspection penetrant composition comprising in percent by mass: fluorescent dye 0.5 dicumyl methane 43.0 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 0.8 n-butyl alcohol 46.7 surfactant (a mixture of mono and dialkyl phenyl polyethylene glycol ethers) 7.0 corrosion inhibitor (polyethylene glycol, molecular mass 300) 2.0 was prepared in the following manner.

0.5 g of the fluorescent dye was dissolved in 45.5 ml of dicumyl methane, while stirring and heating to 1000C on a water bath, adding afterwards 7.0 g of the surfactant and 2.0 g of the corrosion inhibitor.

0.8 g of the visible-colour dye was dissolved in 57.7 ml of n-butyl alcohol without heating.

Then the fluorescent dye solution so obtained and allowed to cool to room temperature was mixed with the visible-colour dye solution and thoroughly stirred.

The resulting penetrant composition thus prepared was tested on the test specimens in a manner similar to that described in Example 1.

Test results: All of the defects present in the test specimens had been revealed.

Colouration and fluorescence of the defect indication traces developed under white light and under ultraviolet light were the same as those cited in Example 37.

Example 40 An inspection penetrant composition was composed of the following components taken in percent by mass: fluorescent dye 0.6 dicumyl methane 40.0 tetraethyl diamino-o-carboxy phenyl xanthenyl chloride visible-colour dye 0.9 n-butyl alcohol 43.5 surfactant (a mixture of mono and dialkyl phenyl polyethylene glycol ethers) 10.0 corrosion inhibitor (polyethylene glycol, molecular mass 300) 5.0 The procedure for preparation of above inspection penetrant composition was similar to that used in Example 39.

The testing procedure for said penetrant composition was similar to that described in Example 1.

Test results: All of the defects present in the test specimens had been revealed.

Colouration and fluorescence of the defect indication traces were the same as in Example 37.

Example 41 (for comparison) The inspection penetrant comprised in percent by mass: fluorescent dye 1.0 ditolyl ethane 62.0 surfactant (a mixture of polyethylene glycol ethers of synthetic primary C,0 to C,8 fatty alcohols) 2.0 n-butyl alcohol 35.0 Said inspection penetrant was prepared in the following manner.

1.0 g of the fluorescent dye was dissolved in 63.5 ml of ditolyl ethane contained in a beaker, while stirring and heating to 1000C on a water bath, adding afterwards 2.0 g of the surfactant.

The resulting solution was thoroughly stirred and then allowed to cool to room temperature.

whereupon 43.2 ml of n-butyl alcohol was introduced in the solution and thoroughly mixed.

The resulting penetrant composition was tested on the test specimens in a manner described in Example 1 for fluorescent method of flaw detection.

Test results: All of the defects present in the test specimens had been revealed but the defects over 0.3-0.4 mm in depth as well as the defects less than 0.3---0.4 mm in depth were revealed under ultraviolet light fluorescent indication traces coloured greenish yellow.

Thus the known penetrant composition fails to provide differentiation of the revealed defects with respect to depth.

Moreover, with the known penetrant composition, the indication traces of the defects are not visible under white light.

The inspection penetrant compositions of the present invention can be advantageously used both for fluorescent and daylight methods of flaw detection, thus revealing defects both under ultraviolet and white lighting conditions.

In addition, the proposed inspection penetrant compositions provide differentiation of the revealed defects with respect to depth. This is one of the most important features inherent in the proposed penetrant compositions.

Claims (6)

Claims

1. An inspection penetrant composition for flaw detection by capillary methods, comprising a fluorescent dye, a surfactant, a solvent system representing a mixture of at least one solvent for the fluorescent dye and at least one oxygencontaining organic compound, and a visiblecolour dye, the proportions of the components taken in percent by mass being as follows: fluorescent dye 0.1 to 4.0 surfactant 2.0 to 10.0 solvent for the fluorescent dye 27.9 to 63.0 oxygen-containing organic compound 30.2 to 60.5 visible-colour dye 0.8 to 1.5

2. An inspection penetrant composition according to Claim 1, wherein the visible-colour dye is an alcohol soluble dye.

3. An inspection penetrant composition according to Claim 2, wherein the alcohol soluble visible-colour dye is tetraethyl diamino-o-carboxy phenyl xanthenyl chloride or 3-amino-6dimethylamino-2-methyl phenazine hydrochloride.

4. An inspection penetrant composition according to any of Claims 1 to 3, which further comprises a corrosion inhibitor, the proportions of the components in percent by mass being as follows: fluorescent dye 0.1 to 4.0 surfactant 2.0 to 10.0 solvent for the fluorescent dye 27.9 to 62.5 oxygen-containing organic compound 30.2 to 50.5 visible-colour dye 0.8 to 1.5 corrosion inhibitor 0.5 to 10.0

5. An inspection penetrant composition according to Claim 5, wherein the corrosion inhibitor is selected from a mixture of cyclohexylamine and fatty acids, aliphatic alkyl amine, polyethylene glycol.

6. An inspection penetrant composition substantially as herein described with reference to the foregoing Examples.