Water-based penetrant for penetrant testing

Abstract

This invention provides a highly accurate aqueous penetrant for penetrant testing. It has no flash point, thus eliminating restrictions on handling and storage quantities under the Fire Service Act. Furthermore, it does not contain volatile organic solvents, minimizing impact on handlers and the environment. Moreover, it is less likely to cause corrosion to various metals, including aluminum alloys, magnesium alloys, and steel. [Solution] A water-based penetrant for penetrant testing containing 20% ​​to 80% by weight of water, 2% to 39% by weight of a glycol ether-based organic solvent without hydroxyl groups, 8% to 45% by weight of a surfactant, 0.2% to 5% by weight of 2,2'-[[(methyl-1H-benzotriazol-1-yl)methyl]imino]bisethanol, and 0.1% to 5% by weight of a dye.

Description

Technical Field

[0001] The present invention relates to an aqueous penetrant for penetrant flaw detection tests. Specifically, the aqueous penetrant is an aqueous penetrant with high flaw detection accuracy, has no flash point and meets the standards of the Fire Service Act, so there are no restrictions on the handling and storage amounts. Also, since it does not contain volatile organic solvents, it has little impact on handlers and the environment. Moreover, the present invention relates to an aqueous penetrant for penetrant flaw detection tests that is less likely to cause corrosion or the like to various metals such as aluminum alloys, magnesium alloys, and steel.

Background Art

[0002] As is well known, the penetrant flaw detection test is a type of non-destructive inspection method and is standardized in JIS Z 2343-1~6 and AMS 2644.

[0003] The basic mode of the penetrant flaw detection test is usually to attach a highly penetrant dye-dissolved staining penetrant to the surface of the test object and allow it to penetrate into the open defect part. Then, the excess staining penetrant remaining on the surface of the test object without penetrating into the defect part is removed. Next, a thin layer of inorganic white powder such as magnesium carbonate powder or calcium carbonate powder (referred to as a "developer" among those skilled in the art) is formed on the surface of the test object, and the staining penetrant penetrating into the open defect part is sucked out onto the surface of the thin layer to reveal a defect indication pattern. Under natural light or white light, or by observing an image taken with a digital camera or the like, the presence and position of the open defect part are detected based on the defect indication pattern.

[0004] In the standards of JIS Z 2343-1~6 and AMS 2644, in the corrosion test for metals, it is required that discoloration, pitting corrosion, and corrosion (hereinafter sometimes referred to as "corrosion or the like") do not occur in all metal pieces of aluminum alloys, magnesium alloys, and steel (hereinafter sometimes referred to as "various metals").

[0005] In the case of a solvent-based penetrant, since corrosion or the like is less likely to occur, it is easy to meet the requirements of the above corrosion test.

[0006] However, because solvent-based penetrants are flammable, they pose a fire hazard, and the handling and storage quantities are strictly regulated by the Fire Service Act.

[0007] Furthermore, because it contains volatile organic solvents (VOCs), it can harm human health and the environment, and is therefore subject to regulations under the Organic Solvent Poisoning Prevention Law. Sellers and buyers must exercise caution when handling it.

[0008] Water-based permeable solutions have no flash point and therefore pose no fire hazard, meaning there are no restrictions on handling or storage quantities, and they have minimal impact on human health and the environment.

[0009] However, with aqueous penetrants, rust and corrosion easily occur on various metal pieces of aluminum alloys, magnesium alloys, and steel due to the water and water-soluble organic solvents they contain, making it difficult to make aqueous penetrants conform to the standards of the aforementioned corrosion test.

[0010] Therefore, there is a need for the development of an aqueous penetrant that offers high flaw detection accuracy, has no restrictions on handling or storage volume, has minimal impact on the human body and the environment, does not cause discoloration, pitting, or corrosion when used on various metals such as aluminum alloys, magnesium alloys, and steel, and meets the requirements of the aforementioned corrosion tests. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Japanese Patent Publication No. 2017-96858 [Overview of the Initiative] [Problems that the invention aims to solve]

[0012] The applicant has developed a water-based penetrant for penetrant testing, as described in Patent Document 1, which contains pentadecenyl succinic anhydride, a solvent having a glycol skeleton, and a water-soluble dye, with water as the solvent, and which is less corrosive even when used on magnesium alloys.

[0013] The inventors conducted numerous trial-and-error experiments to develop an aqueous penetrant that would not cause corrosion on many metal pieces. As a result, they have found an aqueous penetrant for penetrant testing that contains 20% to 80% by weight of water, 2% to 39% by weight of an organic solvent, 8% to 45% by weight of a surfactant, 0.2% to 5% by weight of a rust inhibitor, and 0.1% to 5% by weight of a dye, wherein the organic solvent is glycol ether without hydroxyl groups. A remarkable finding has been obtained that a water-based penetrant for penetrant testing, which is an organic solvent and whose rust inhibitor is 2,2'-[[(methyl-1H-benzotriazol-1-yl)methyl]imino]bisethanol, is a water-based penetrant with high inspection accuracy that can obtain clear indication patterns, does not cause discoloration, pitting, or corrosion on all metal pieces of aluminum alloy, magnesium alloy, and steel, and is a water-based penetrant that meets the requirements of the corrosion test, thereby achieving the aforementioned technical objective. [Means for solving the problem]

[0014] The aforementioned technical problems can be solved by the present invention as follows.

[0015] The present invention relates to an aqueous penetrant for penetrant testing, comprising 20% ​​or more by weight of water and 80% or less by weight, 2% or more by weight of an organic solvent and 39% or less by weight, 8% or more by weight of a surfactant and 45% or less by weight, 0.2% or more by weight of a rust inhibitor and 5% or more by weight of a dye, wherein the organic solvent is a glycol ether-based organic solvent without hydroxyl groups, and the rust inhibitor is 2,2'-[[(methyl-1H-benzotriazol-1-yl)methyl]imino]bisethanol.

[0016] The present invention also relates to the aqueous penetrant for penetrant inspection described above, wherein the glycol ether-based organic solvent without the hydroxyl group is one or more selected from diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and dimethoxytetraethylene glycol.

[0017] The present invention also relates to the aqueous penetrant for penetrant inspection described above, wherein the dye is a fluorescent dye or a visible color dye.

[0018] The present invention also relates to a method for producing the aqueous penetrant for penetrant inspection described above, which is produced by mixing and stirring water, an organic solvent, a surfactant, a rust inhibitor, and a dye.

Advantages of the Invention

[0019] The aqueous penetrant for penetrant inspection of the present invention is an aqueous penetrant with high inspection accuracy capable of obtaining a clear defect indication pattern, and can suppress discoloration, pitting corrosion, and corrosion of all metal pieces of aluminum alloy, magnesium alloy, and steel. Therefore, it is an aqueous penetrant for penetrant inspection that meets the requirements of the above corrosion test.

[0020] Moreover, since it is aqueous, there is no risk of fire, and it is not subject to the handling quantity and storage quantity restrictions under the Fire Service Act.

[0021] In addition, since it does not contain volatile organic solvents (VOCs), it has little impact on the human body and the environment of handlers, etc..

[0022] For the aqueous penetrant in the present invention, a high-precision penetrant inspection test can be carried out using either a water-soluble fluorescent dye or a visible color dye

Embodiments for Carrying Out the Invention

[0023] The present invention is an aqueous penetrant for penetrant inspection containing water, an organic solvent, a surfactant, a rust inhibitor, and a dye.

[0024] The water contained in the aqueous penetrant in the present invention may be any of pure water, distilled water, and tap water.

[0025] The water content of the aqueous penetrant of the present invention is preferably 20% to 80% by weight, more preferably 40% to 70% by weight.

[0026] If it is less than 20% by weight, the compatibility may be poor and the flaw detection test accuracy may decrease. If it exceeds 80% by weight, the effect of the rust inhibitor may be weakened and corrosion may occur on various metals.

[0027] The organic solvent in the present invention is a glycol ether-based organic solvent without a hydroxyl group.

[0028] This is because glycol ether-based organic solvents with a hydroxyl group may cause corrosion on various metals.

[0029] The glycol ether-based organic solvent without a hydroxyl group is not particularly limited, and examples include diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and dimethoxytetraethylene glycol.

[0030] The content of the glycol ether-based organic solvent without a hydroxyl group is preferably 2% to 39% by weight, more preferably 7% to 20% by weight.

[0031] If the content is less than 2% or more than 39% by weight, the compatibility may deteriorate and the flaw detection accuracy may decrease.

[0032] The surfactants used in this invention are not particularly limited, but examples include Pegnol® ST-7, Pegnol ST-9, Pegnol ST-12 (all manufactured by Toho Chemical Industry Co., Ltd.), Softanol® 70 (manufactured by Nippon Shokubai Co., Ltd.), Paionin D-1106DIR (manufactured by Takemoto Oil & Fat Co., Ltd.), Naroacty® CL95 (manufactured by Sanyo Chemical Industries, Ltd.), and Neugen® LF-60X (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).

[0033] The surfactant content in this invention is preferably 8% to 45% by weight, and more preferably 14% to 30% by weight.

[0034] This is because if the content is less than 8% by weight or more than 45% by weight, the compatibility will deteriorate, and the accuracy of flaw detection may decrease.

[0035] The rust inhibitor in this invention is 2,2'-[[(methyl-1H-benzotriazol-1-yl)methyl]imino]bisethanol (manufactured by Johoku Chemical Industry Co., Ltd.).

[0036] This is because it has good compatibility with water, organic solvents, surfactants, and dyes, enabling high-precision flaw detection tests, and is less likely to cause discoloration, pitting, and corrosion in all metals, including aluminum alloys, magnesium alloys, and steel, thus becoming a water-based penetrant that meets the requirements of the aforementioned corrosion tests.

[0037] The rust inhibitor content is preferably 0.2% to 5% by weight, and more preferably 1% to 2% by weight.

[0038] If the content is less than 0.2% by weight, the rust prevention effect will not be sufficient, and if it exceeds 5% by weight, the compatibility will deteriorate, which may reduce the accuracy of flaw detection and may cause corrosion of various metal pieces.

[0039] The dye used in the aqueous penetrant in this invention may be either a fluorescent dye or a visible color dye.

[0040] While the dyes are not particularly limited, examples include Oplus Yellow 156 (manufactured by Orient Chemical Industry Co., Ltd.) and MDAC (7-diethylamino-4-methylcoumarin) as fluorescent dyes, and SPITASOL FAST RED 260S (manufactured by Futaba Chemical Research Institute Co., Ltd.) and Alcohol Rhodamine B (manufactured by Shirado Chemical Co., Ltd.) as visible color dyes.

[0041] The aqueous penetrant in this invention can be produced by mixing and stirring water, an organic solvent, a surfactant, a rust inhibitor, and a dye.

[0042] This document describes one embodiment of a penetrant testing method using an aqueous penetrant according to the present invention. In an inspection environment at room temperature (approximately 20°C), the aqueous penetrant solution according to the present invention, which has been stored at the same room temperature, is applied to the surface of the object to be inspected and allowed to penetrate into the opening defects (penetration treatment). Next, the surface of the object under inspection is washed and removed using tap water or a cleaning agent such as EcoCheck® ER-ST (manufactured by Marktec Co., Ltd.) at a water pressure of approximately 0.2 MPa and a flow rate of 5 L / min, removing any excess penetrant that remains on the surface of the object under inspection without penetrating into the defective area (washing treatment). After drying the object to be inspected, an inorganic white powder such as magnesium carbonate powder or calcium carbonate powder, or a developer such as EcoCheck® UD-ST (manufactured by Marktec Co., Ltd.) is applied to the surface. The defect indication pattern that appears when the water-based penetrant remaining in the defective area soaks into the developer is observed with the naked eye, or by taking a photograph with a digital camera and observing it, thereby detecting the opening defect in the object to be inspected. [Examples]

[0043] The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited thereto.

[0044] The raw materials listed in Table 1 were mixed and stirred at 50-80 rpm for 30 minutes as described in Tables 2-4 to produce the aqueous permeates for each of the examples and comparative examples.

[0045] The aqueous permeates in the examples and comparative examples were evaluated as follows.

[0046] (compatibility) The samples were visually inspected and evaluated as follows: those with no undissolved dye or cloudy penetrating solution were marked with "○", and those with undissolved dye or cloudy penetrating solution were marked with "×".

[0047] (flash point) The flash point was measured using a Cleveland open-type flash point analyzer ACO-8 (manufactured by Tanaka Scientific Instruments Co., Ltd.).

[0048] We evaluated the samples as follows: those that boiled at around 100°C and did not have a flash point were marked with "○", and those that had a flash point before boiling were marked with "×".

[0049] (Penetrant testing) Penetrant testing was performed using aluminum quenching test specimens at room temperature of 20°C.

[0050] After applying the aqueous penetrant solutions of the examples and comparative examples to the test surface and allowing them to stand for 5 minutes, the test surface was washed with a water shower at a water pressure of 0.2 MPa to remove excess penetrant solution.

[0051] After washing, the test specimens were dried for 5 minutes using a hot air circulating dryer at 50°C.

[0052] When a visible color dye was used as the dye, a developer (Ecocheck® Developer ED-ST / manufactured by Marktec Co., Ltd.) was sprayed onto the test surface to form a coating, and the defect indication pattern was visually observed under white light.

[0053] When fluorescent dyes were used as the dyes, the defect indication patterns were visually observed in a darkroom using a black light (Super Light D-40L / Marktec Co., Ltd.) without using a developer.

[0054] We evaluated the results as follows: "○" indicates that all defect indication patterns were detected, and "×" indicates that none of the defect indication patterns were detected or that some defect indication patterns were not detected.

[0055] (Corrosion test) The following materials were used as metal corrosion test specimens: 4130 alloy steel (length 101 mm, width 25 mm, thickness 1 mm), 7075-T6 aluminum alloy (length 60 mm, width 15 mm, thickness 3 mm), and AZ-31B magnesium alloy (length 100 mm, width 13 mm, thickness 1 mm).

[0056] Each test specimen was polished with 320-grit sandpaper and then cleaned with acetone.

[0057] Each test specimen was immersed halfway along its length in a beaker containing the respective aqueous permeate for the examples and comparative examples. After standing at 50°C for 3 hours, the test specimens were removed, washed with acetone, and visually observed.

[0058] For each test specimen, the immersion points were evaluated as follows: those without discoloration, pitting, or corrosion were marked with "○", and those with discoloration, pitting, or corrosion were marked with "×".

[0059] The formulation amounts and evaluation results for the examples are shown in Tables 2 and 3, and the formulation amounts and evaluation results for the comparative examples are shown in Tables 4 and 5. In the evaluation column of the tables, "-" indicates that the compatibility was poor and other evaluations could not be performed. The unit of measurement for the proportion of each ingredient is weight percent. The fluorescent dye used was a mixture of Oplus Yellow 156 (Y) and MDAC (M) as shown in Table 1.

[0060] [Table 1]

[0061] [Table 2]

[0062] [Table 3]

[0063] [Table 4]

[0064] [Table 5]

[0065] Tables 2 to 5 demonstrate that the aqueous penetrant of the present invention allows for high-precision flaw detection testing, has no flash point, and is therefore not subject to restrictions on handling or storage quantities under the Fire Service Act. Furthermore, it has been proven that it does not cause corrosion or other damage to various metal fragments of aluminum alloys, magnesium alloys, and alloy steels. [Industrial applicability]

[0066] The aqueous penetrant according to the present invention is an aqueous penetrant with high accuracy in flaw detection, capable of obtaining clear defect indication patterns. Since it has no flash point, there are no restrictions on handling or storage volume under the Fire Service Act. Furthermore, since it does not contain volatile organic solvents, it has little impact on handlers and the environment. Moreover, it is less likely to cause corrosion to various metals such as aluminum alloys, magnesium alloys, and steel, making it an aqueous penetrant for penetrant testing that meets the requirements of the aforementioned corrosion tests. Therefore, the industrial applicability of this invention is high.

Claims

1. A water-based penetrant for penetrant testing, comprising 20% ​​or more by weight of water and 80% or less by weight of an organic solvent, 2% or more by weight of an organic solvent and 39% or less by weight of an organic solvent, 8% or more by weight of a surfactant and 45% or less by weight of a surfactant, 0.2% or more by weight of a rust inhibitor and 5% or more by weight of a dye, wherein the organic solvent is a glycol ether-based organic solvent without hydroxyl groups, and the rust inhibitor is 2,2'-[[(methyl-1H-benzotriazole-1-yl)methyl]imino]bisethanol.

2. The aqueous penetrant for penetrant testing according to claim 1, wherein the glycol ether-based organic solvent without hydroxyl groups is selected from one or more of diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and dimethoxytetraethylene glycol.

3. The aqueous penetrant for penetrant testing according to claim 1 or 2, wherein the dye is a fluorescent dye or a visible color dye.

4. A method for producing an aqueous penetrant for penetrant testing according to claim 1 or 2, comprising mixing and stirring water, an organic solvent, a surfactant, a rust inhibitor, and a dye.

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