A flaw detection coupling fluid and its preparation method

Abstract

This application relates to the field of nondestructive testing, specifically disclosing a flaw detection coupling fluid and its preparation method. The flaw detection coupling fluid comprises the following raw materials by mass percentage: ethylene glycol 35-70%; rust inhibitor 1-2.5%; organic carboxylic acid composite functional agent 2-5%; defoamer 0.005-0.03%; dye 0-0.006%; and water as the balance. The organic carboxylic acid composite functional agent comprises the following raw materials: inorganic alkali, organic dicarboxylic acid, methylbenzotriazole, organic sodium salt, diethylene glycol, dipropylene glycol monomethyl ether, and water. The preparation method includes the following steps: mixing water and ethylene glycol, then adding the organic carboxylic acid composite functional agent and rust inhibitor, stirring at room temperature, then adding the defoamer and dye, stirring, filtering, and filling to obtain the flaw detection coupling fluid. This application has the advantage of producing a flaw detection coupling fluid with recyclability and excellent recyclability.

Description

Technical Field

[0001] This application relates to the field of ultrasonic testing, and more specifically, to a flaw detection coupling fluid and its preparation method. Background Technology

[0002] Non-destructive testing (NDT) is an important technical means to ensure the manufacturing quality and service condition of industrial products. It belongs to the category of non-destructive testing methods. Among them, ultrasonic testing is one of the most widely used NDT methods. Ultrasonic testing technology is used in railway engineering, locomotive, rolling stock, power supply and other systems. Ultrasonic testing technology is also mainly used for the testing of track steel base materials and welds.

[0003] During ultrasonic testing, the air between the ultrasonic probe and the surface of the workpiece will hinder the transmission of ultrasonic waves into the workpiece. In order for the ultrasonic waves to effectively penetrate the workpiece and ensure sufficient sound intensity transmittance on the probe surface to achieve the purpose of detection, a liquid conductive medium is needed to connect the probe and the workpiece. This medium is called coupling fluid, also known as ultrasonic testing coupling fluid.

[0004] The purpose of using coupling fluid is twofold: first, to fill the tiny gaps between the contact surfaces, preventing the minute air particles in these gaps from affecting the penetration of ultrasonic waves; second, through the "transition" effect of the coupling fluid, to reduce the acoustic impedance difference between the ultrasonic probe and the surface of the workpiece being measured, thereby reducing the reflection loss of ultrasonic energy at this interface. Additionally, it also acts as a "lubricant," reducing friction between the ultrasonic probe surface and the workpiece surface, allowing the ultrasonic probe to slide flexibly during testing and extending its service life.

[0005] For example, Chinese patent application publication number CN107367551A discloses an ultrasonic testing coupling agent for rail welds. By mass percentage, the coupling agent contains: 10-40% solvent, 1-3% gelling agent, 1-3% colloidal stabilizer, 0.02-2% water-soluble rust inhibitor, 0.01-0.5% additives, and the balance is water. The gelling agent is selected from one or more of carbomer, calcium alginate, hydroxypropyl methylcellulose, methylcellulose, hydroxymethylcellulose, or sodium hydroxymethylcellulose. It has good acoustic properties, low-temperature performance, and rust prevention performance.

[0006] However, the above-mentioned coupling agents contain gelling agents, and the final product exists in colloidal form. Moreover, most products currently add colloids or esters as stabilizers, which means that the flaw detection coupling agents cannot be recycled and can only be used as disposable products, which is not conducive to improving their economic efficiency. Summary of the Invention

[0007] In order to improve the recyclability of the flaw detection coupling agent and to ensure its excellent performance during recycling, this application provides a flaw detection coupling fluid and its preparation method.

[0008] Firstly, this application provides a flaw detection coupling fluid, employing the following technical solution:

[0009] A flaw detection coupling fluid comprises the following raw materials by mass percentage:

[0010] Ethylene glycol 35-70%;

[0011] Rust inhibitor 1-2.5%;

[0012] Organic carboxylic acid type compound functional agent 2-5%;

[0013] Defoamer 0.005-0.03%;

[0014] Dye content: 0-0.006%;

[0015] Water balance;

[0016] The organic carboxylic acid type composite functional agent comprises the following raw materials in parts by weight:

[0017] 3-5 parts inorganic base, 25-35 parts organic dicarboxylic acid, 15-20 parts methylbenzotriazole, 10-15 parts organic sodium salt, 5-12 parts diethylene glycol, 5-10 parts dipropylene glycol monomethyl ether and 30-40 parts water.

[0018] By adopting the above technical solution, ethylene glycol in this application plays an excellent antifreeze role. Combined with the addition of rust remover and organic carboxylic acid composite functional agent, the rust remover achieves online rust prevention. The organic dicarboxylic acid composite functional agent plays an excellent anti-corrosion role. Combined with methylbenzotriazole as a rust inhibitor and slow-release agent, and further combined with organic sodium salt, using a unique organic acid compounding technology, it provides excellent protection for various metals and exhibits excellent rust and corrosion prevention properties. The addition of inorganic alkali facilitates the dissolution of methylbenzotriazole in dilute alkaline solution, thereby enabling the formulation of an aqueous solution and facilitating product recycling. Diethylene glycol has good wetting and antifreeze properties. Dipropylene glycol monomethyl ether acts as a dispersant and diluent, serving as an antifreeze component, and an antifoaming agent to remove bubbles generated during the mixing of raw materials in water.

[0019] The final formulation of ethylene glycol, rust inhibitor, and organic carboxylic acid composite functional agent results in a flaw detection coupling fluid with good low-temperature fluidity, sound transmission, and wettability. It has a freezing point ≥ -45℃, exhibiting no freezing or solidification. It also possesses high acoustic impedance, high transmittance, and good sound transmission performance. Furthermore, it is rust-proof and corrosion-resistant, suitable for ultrasonic testing of various metal and non-metal workpieces. Its high boiling point makes it non-volatile and resistant to rancidity, thus having wide applications in ultrasonic flaw detection. Moreover, the flaw detection coupling fluid prepared in this application is an aqueous solution; after recycling and filtration, it can be reused while still maintaining excellent low-temperature fluidity and sound transmission, without affecting its re-application in flaw detection, demonstrating excellent recyclability.

[0020] Optionally, the mass percentage of the dye in the flaw detection coupling fluid raw material is 0.001-0.006%.

[0021] Optionally, the organic carboxylic acid type composite functional agent is prepared by the following method:

[0022] An inorganic base is dissolved in water, then methylbenzotriazole, an organic sodium salt, and an organic dicarboxylic acid are added. After mixing, diethylene glycol and dipropylene glycol monomethyl ether are added to obtain the product.

[0023] By adopting the above technical solution, an inorganic alkali is first dissolved in water to obtain a dilute alkali solution, and then methylbenzotriazole is added to dissolve it before adding other raw materials to obtain the final solution.

[0024] Optionally, the rust inhibitor is selected from one or more of triethanolamine, monoethanolamine, trisodium phosphate, and hexamethylenetetramine.

[0025] By adopting the above technical solution, the above rust inhibitor, as a water-soluble rust inhibitor, has excellent rust prevention performance and excellent reusability when reused.

[0026] Optionally, the organic dicarboxylic acid is selected from one or more of sebacic acid, oxalic acid, glutamic acid, and aspartic acid.

[0027] Optionally, the organic dicarboxylic acid is selected from aspartic acid and sebacic acid in a mass ratio of 1:(2-3).

[0028] Optionally, the organic sodium salt is selected from sodium benzoate and sodium methylsilicate in a mass ratio of 1:(1.2-1.5).

[0029] By adopting the above technical solution, the rust and corrosion prevention performance is better when the above organic acid and organic sodium salt are combined, and the reuse performance is also better.

[0030] Optionally, the diethylene glycol is obtained by pretreatment using the following method:

[0031] Dissolve 2-5 parts by weight of microcrystalline cellulose in 3-5 parts of N,N-dimethylformamide, then add 3-5 parts by weight of microcrystalline cellulose.

[0032] Add 1-3 parts of stearic acid to castor oil, mix, then add 10-20 parts of diethylene glycol, mix again, and obtain pretreated diethylene glycol.

[0033] By adopting the above technical solution, since diethylene glycol has a certain degree of hygroscopicity, during use and reuse, its hygroscopicity absorbs moisture from the air, causing changes in the flaw detection coupling agent and affecting the coupling performance after reuse. By modifying it with microcrystalline cellulose and stearic acid, its hygroscopicity is improved, and the addition of castor oil promotes the miscibility of diethylene glycol with other raw materials of the aqueous agent of this application. The final flaw detection coupling fluid has better performance and reusability.

[0034] Secondly, this application provides a method for preparing a flaw detection coupling fluid, which adopts the following technical solution:

[0035] A method for preparing a flaw detection coupling fluid includes the following steps:

[0036] Water and ethylene glycol are mixed and prepared, then an organic carboxylic acid type coolant composite functional agent and a rust inhibitor are added, stirred at room temperature, then an antifoaming agent and dye are added, stirred, filtered, and filled to obtain the flaw detection coupling fluid.

[0037] By adopting the above technical solution, this application first prepares water and ethylene glycol-based liquid, and then adds other raw materials. The preparation method is simple and easy to industrialize.

[0038] In summary, this application has the following beneficial effects:

[0039] 1. The compounding of ethylene glycol, rust inhibitor, and organic carboxylic acid type composite functional agent in this application results in a flaw detection coupling fluid with good low-temperature fluidity, sound transmission, and wettability. It has a freezing point ≥ -45℃, with no freezing or solidification; it has high acoustic impedance, high transmittance, and good sound transmission performance; it also has rust and corrosion resistance, making it suitable for ultrasonic testing of various metal and non-metal workpieces. Its high boiling point makes it non-volatile and non-acidic, and it has wide applications in the field of ultrasonic flaw detection. Furthermore, the flaw detection coupling fluid prepared in this application is an aqueous solution; after recycling and filtration, it can be reused while still exhibiting excellent low-temperature fluidity and sound transmission, without affecting its re-application in flaw detection, demonstrating excellent recyclability.

[0040] 2. In this application, the organic dicarboxylic acid in the organic carboxylic acid composite functional agent plays an excellent role in corrosion prevention. Combined with methylbenzotriazole as a rust inhibitor and slow-release agent, and further combined with organic sodium salt, it adopts a unique organic acid compounding technology to provide excellent protection for a variety of metals and has excellent rust and corrosion prevention performance. The addition of inorganic alkali is conducive to the dissolution of methylbenzotriazole in dilute alkaline solution, thereby preparing an aqueous solution and facilitating product recycling and reuse. Diethylene glycol has good wettability and antifreeze properties, and dipropylene glycol monomethyl ether is used as a dispersant and diluent as an antifreeze component. The addition of diethylene glycol and dipropylene glycol monomethyl ether significantly improves the coupling performance of the flaw detection coupling fluid.

[0041] 3. In this application, diethylene glycol is pretreated and modified with microcrystalline cellulose and stearic acid to improve its hygroscopicity. The addition of castor oil promotes the miscibility of diethylene glycol with other raw materials of the aqueous solution of this application. The resulting flaw detection coupling fluid has better performance and reusability. This solves the problem that diethylene glycol has a certain degree of hygroscopicity, which causes changes in the flaw detection coupling fluid due to the absorption of moisture from the air during use and reuse, thus affecting the coupling performance after reuse. Detailed Implementation

[0042] The following detailed description of this application is provided in conjunction with the embodiments. It should be noted that: unless otherwise specified, the conditions in the following embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following embodiments are all from commercially available sources.

[0043] The defoamer used in the following examples is a commercially available water-soluble defoamer, model AT-930.

[0044] The following preparation examples 1-10 and comparative preparation examples 1-2 are examples of the preparation of organic carboxylic acid type composite functional agents and comparative preparation examples. Preparation Example 1

[0045] A method for preparing an organic carboxylic acid type composite functional agent includes the following steps:

[0046] Dissolve 4 kg of inorganic base in 35 kg of water, then add 18 kg of methylbenzotriazole, 12 kg of organic sodium salt and 30 kg of organic dicarboxylic acid. After mixing, add 8 kg of diethylene glycol and 8 kg of dipropylene glycol monomethyl ether to obtain the final product.

[0047] Among them, the organic dicarboxylic acids selected are aspartic acid and sebacic acid in a mass ratio of 1:2.5;

[0048] The organic sodium salt is selected from sodium benzoate and sodium methylsilicate in a mass ratio of 1:1.4;

[0049] For inorganic alkalis, caustic soda flakes are selected.

[0050] Preparation Example 2

[0051] A method for preparing an organic carboxylic acid type composite functional agent includes the following steps:

[0052] Dissolve 3 kg of inorganic base in 30 kg of water, then add 15 kg of methylbenzotriazole, 10 kg of organic sodium salt and 25 kg of organic dicarboxylic acid. After mixing, add 5 kg of diethylene glycol and 5 kg of dipropylene glycol monomethyl ether to obtain the final product.

[0053] Among them, the organic dicarboxylic acid is selected from one or more of sebacic acid, oxalic acid, glutamic acid and aspartic acid; the organic dicarboxylic acid is selected from aspartic acid and sebacic acid in a mass ratio of 1:2.

[0054] The organic sodium salt is selected from sodium benzoate and sodium methylsilicate in a mass ratio of 1:1.2;

[0055] For inorganic alkalis, caustic soda flakes are selected.

[0056] Preparation Example 3

[0057] A method for preparing an organic carboxylic acid type composite functional agent includes the following steps:

[0058] Dissolve 5 kg of inorganic base in 40 kg of water, then add 20 kg of methylbenzotriazole, 15 kg of organic sodium salt and 35 kg of organic dicarboxylic acid. After mixing, add 12 kg of diethylene glycol and 10 kg of dipropylene glycol monomethyl ether to obtain the final product.

[0059] Among them, the organic dicarboxylic acids selected are aspartic acid and sebacic acid in a mass ratio of 1:3;

[0060] The organic sodium salt is selected from sodium benzoate and sodium methylsilicate in a mass ratio of 1:1.5;

[0061] For inorganic alkalis, caustic soda flakes are selected.

[0062] Preparation Example 4

[0063] A method for preparing an organic carboxylic acid type composite functional agent is carried out according to the method in Preparation Example 1, except that sebacic acid is selected as the organic dicarboxylic acid.

[0064] Preparation Example 5

[0065] A method for preparing an organic carboxylic acid type composite functional agent is carried out according to the method in Preparation Example 1, except that aspartic acid is selected as the organic dicarboxylic acid.

[0066] Preparation Example 6

[0067] A method for preparing an organic carboxylic acid type composite functional agent is carried out according to the method in Preparation Example 1, except that aspartic acid is replaced with oxalic acid in equal amounts.

[0068] Preparation Example 7

[0069] A method for preparing an organic carboxylic acid type composite functional agent is carried out according to the method in Preparation Example 1, except that sodium benzoate is used as the organic sodium salt.

[0070] Preparation Example 8

[0071] A method for preparing an organic carboxylic acid type composite functional agent is carried out according to the method in Preparation Example 1, except that diethylene glycol is added after pretreatment as follows:

[0072] Dissolve 3 kg of microcrystalline cellulose in 4 kg of N,N-dimethylformamide, then add 4 kg of castor oil and 2 kg of stearic acid, stir and mix, then add 15 kg of diethylene glycol and stir and mix to obtain pretreated diethylene glycol.

[0073] Preparation Example 9

[0074] A method for preparing an organic carboxylic acid type composite functional agent is carried out according to the method in Preparation Example 1, except that diethylene glycol is added after pretreatment as follows:

[0075] Dissolve 2 kg of microcrystalline cellulose in 3 kg of N,N-dimethylformamide, then add 3 kg of castor oil and 1 kg of stearic acid, stir and mix, then add 10 kg of diethylene glycol and stir and mix to obtain pretreated diethylene glycol.

[0076] Preparation Example 10

[0077] A method for preparing an organic carboxylic acid type composite functional agent is carried out according to the method in Preparation Example 1, except that diethylene glycol is added after pretreatment as follows:

[0078] Dissolve 5 kg of microcrystalline cellulose in 5 kg of N,N-dimethylformamide, then add 5 kg of castor oil and 3 kg of stearic acid, stir and mix, then add 20 kg of diethylene glycol and stir and mix to obtain pretreated diethylene glycol.

[0079] Comparative Preparation Example 1

[0080] A method for preparing an organic carboxylic acid type composite functional agent is carried out according to the method in Preparation Example 1, except that diethylene glycol is not added to the raw materials.

[0081] Comparative Preparation Example 2

[0082] A method for preparing an organic carboxylic acid type composite functional agent is carried out according to the method in Preparation Example 1, except that dipropylene glycol monomethyl ether is not added to the raw materials.

[0083] The following preparation examples 8-10 are examples of the preparation of pretreated diethylene glycol.

[0084] Example

[0085] Example 1

[0086] A flaw detection coupling fluid, with the following weight percentage of each raw material per 100g:

[0087] 58% ethylene glycol;

[0088] Rust inhibitor 1.65%;

[0089] 4% organic carboxylic acid type compound functional agent;

[0090] Defoamer 0.025%;

[0091] Dye 0.005%;

[0092] Water balance.

[0093] Among them, triethanolamine is selected as the rust inhibitor;

[0094] The organic carboxylic acid type composite functional agent is selected from the organic carboxylic acid type composite functional agent prepared in Preparation Example 1;

[0095] The preparation method of this flaw detection coupling agent includes the following steps:

[0096] Water and ethylene glycol are mixed and prepared, then organic carboxylic acid type coolant composite functional agent and rust inhibitor are added, and the mixture is stirred at room temperature for 20 minutes. Then defoamer and dye are added, and the mixture is stirred for 10 minutes. The mixture is then filtered through a 400-mesh filter and bottled to obtain the flaw detection coupling fluid.

[0097] Example 2

[0098] A flaw detection coupling fluid, with the following weight percentage of each raw material per 100g:

[0099] 35% ethylene glycol;

[0100] Rust inhibitor 2.5%;

[0101] 5% organic carboxylic acid type compound functional agent;

[0102] Defoamer 0.005%;

[0103] Water balance.

[0104] Among them, hexamethylenetetramine is selected as the rust inhibitor;

[0105] The organic carboxylic acid type composite functional agent is selected from the organic carboxylic acid type composite functional agent prepared in Preparation Example 2;

[0106] The preparation method of this flaw detection coupling agent includes the following steps:

[0107] Water and ethylene glycol are mixed and prepared, then an organic carboxylic acid type coolant composite functional agent and rust inhibitor are added, and the mixture is stirred at room temperature for 18 minutes. Then, defoamer and dye are added, and the mixture is stirred for 10 minutes. The mixture is then filtered through a 400-mesh filter and bottled to obtain the flaw detection coupling fluid.

[0108] Example 3

[0109] A flaw detection coupling fluid, with the following weight percentage of each raw material per 100g:

[0110] 70% ethylene glycol;

[0111] Rust inhibitor 1%;

[0112] Organic carboxylic acid type compound functional agent 2%;

[0113] Defoamer 0.03%;

[0114] Dye 0.006%;

[0115] Water balance.

[0116] Among them, trisodium phosphate is selected as the rust inhibitor;

[0117] The organic carboxylic acid type composite functional agent is selected from the organic carboxylic acid type composite functional agent prepared in Preparation Example 3;

[0118] The preparation method of this flaw detection coupling agent includes the following steps:

[0119] Water and ethylene glycol are mixed and prepared, then an organic carboxylic acid type coolant composite functional agent and rust inhibitor are added, and the mixture is stirred at room temperature for 25 minutes. Then, defoamer and dye are added, and the mixture is stirred for 10 minutes. The mixture is then filtered through a 400-mesh filter and bottled to obtain the flaw detection coupling fluid.

[0120] Example 4

[0121] A flaw detection coupling fluid, which differs from Example 1 in that the weight percentages of each raw material are as follows:

[0122] 40% ethylene glycol;

[0123] Rust inhibitor 1.4%;

[0124] 3% organic carboxylic acid type compound functional agent;

[0125] Defoamer 0.018%;

[0126] Dye 0.003%;

[0127] Water balance.

[0128] The preparation method of the flaw detection coupling fluid is the same as that in Example 1.

[0129] Example 5

[0130] A flaw detection coupling fluid and its preparation method are disclosed, which differ from Example 1 in that the rust inhibitor is hexamethylenetetramine.

[0131] Examples 6-12

[0132] A flaw detection coupling fluid and its preparation method are carried out according to Example 1, except that the organic carboxylic acid type composite functional agent is selected from the organic carboxylic acid type composite functional agents prepared in Examples 4-10.

[0133] Comparative Example 1

[0134] A flaw detection coupling fluid, which differs from that in Example 1, replaces the organic carboxylic acid type composite functional agent with ethylene glycol and rust inhibitor in equal proportion.

[0135] Comparative Example 2

[0136] A flaw detection coupling fluid, which differs from Example 1 in that the organic carboxylic acid type composite functional agent is selected from the organic carboxylic acid type composite functional agent prepared in Comparative Preparation Examples 1-2.

[0137] Performance testing

[0138] The flaw detection coupling fluids prepared in the embodiments and comparative examples of this application were tested for freezing point, acoustic performance, and rust prevention performance. Furthermore, after applying the above-mentioned flaw detection coupling fluids to the online fault detection system of the EMU depot, they were recycled, filtered, and reused. The freezing point, acoustic performance, and rust prevention performance of the coupling fluids after three cycles were tested. The freezing point was determined according to SH / T0090-1991, and the rust prevention performance was determined according to SH / T0085-1991 - glassware method (brass and cast iron conditions). The testing conditions were 88±2℃ for 336±2h, and the mass change (mg) was measured to characterize its rust prevention performance. The product test results are shown in Table 1 below, and the performance test results after three cycles are shown in Table 2 below.

[0139] Table 1: Test Results of the Prepared Products

[0140]

[0141]

[0142] Table 2: Test results after 3 cycles of use

[0143]

[0144] In addition, the pH of the flaw detection coupling fluid prepared in the embodiments of this application was tested, and its pH was between 7 and 8, which is neutral and non-toxic and harmless to the human body.

[0145] As shown in Table 1 above, the flaw detection coupling fluid prepared in this application has excellent sound transmission performance and rust and corrosion prevention performance. Furthermore, its freezing point can reach -47℃, exhibiting excellent low-temperature flow performance. Referring to the test results of Examples 1 and 5, when hexamethyleneimine was selected as the rust inhibitor in Example 5, the resulting flaw detection coupling fluid exhibited superior sound transmission, rust and corrosion prevention performance, and recyclability.

[0146] Combining the test results of Examples 1, 6, and 7, it can be seen that when sebacic acid and aspartic acid are selected as the organic dicarboxylic acid in the organic carboxylic acid composite functional agent, the rust and corrosion prevention performance and sound transmission performance are superior compared to when only sebacic acid or aspartic acid is added, and the product performance is better maintained after recycling. Combining the test results of Example 8, when ordinary alkyl acids are selected as the organic dicarboxylic acid, the rust and corrosion prevention performance is significantly reduced compared to the combination of sebacic acid and aspartic acid, and the performance is superior when sebacic acid and aspartic acid are selected as the organic dicarboxylic acid. Referring to the test results of Examples 1 and 9, it can be seen that the performance of organic sodium salt with added sodium methylsilicate is greatly improved compared to the commonly added sodium benzoate.

[0147] Combining the test results of Examples 1 and 10-12, it can be seen that the performance of the flaw detection coupling fluid is significantly improved after pretreatment and addition of diethylene glycol in the organic carboxylic acid composite functional agent. Furthermore, the product performance remains largely unchanged after recycling, with almost no loss. Combining the test results of Examples 1 and Comparative Examples 2 and 3, it is clear that when diethylene glycol and dipropylene glycol monomethyl ether are not added to the organic carboxylic acid composite functional agent, its sound transmission and rust / corrosion prevention performance are significantly reduced. Referring to the test results of Comparative Example 1, when only ethylene glycol and rust inhibitor are added to the flaw detection coupling fluid, without the addition of the organic carboxylic acid composite functional agent, the sound transmission and rust / corrosion prevention performance are significantly reduced. Moreover, when it is recycled, filtered, and reused, its performance is noticeably reduced.

[0148] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A flaw detection coupling fluid, characterized in that, Including the following percentages of raw materials by weight: Ethylene glycol 35-70%; Rust inhibitor 1-2.5%; Organic carboxylic acid type compound functional agents 2-5%; Defoamer 0.005-0.03%; Dye content: 0-0.006%; Water balance; The organic carboxylic acid type composite functional agent comprises the following raw materials in parts by weight: 3-5 parts inorganic base, 25-35 parts organic dicarboxylic acid, 15-20 parts methylbenzotriazole, 10-15 parts organic sodium salt, 5-12 parts diethylene glycol, 5-10 parts dipropylene glycol monomethyl ether and 30-40 parts water.

2. The flaw detection coupling fluid according to claim 1, characterized in that: The mass percentage of the dye in the raw material of the flaw detection coupling fluid is 0.001-0.006%.

3. The flaw detection coupling fluid according to claim 1, characterized in that: The organic carboxylic acid type composite functional agent is prepared by the following method: An inorganic base is dissolved in water, then methylbenzotriazole, an organic sodium salt, and an organic dicarboxylic acid are added. After mixing, diethylene glycol and dipropylene glycol monomethyl ether are added to obtain the product.

4. The flaw detection coupling fluid according to claim 1, characterized in that: The rust inhibitor is selected from one or more of triethanolamine, monoethanolamine, trisodium phosphate, and hexamethylenetetramine.

5. The flaw detection coupling fluid according to claim 1, characterized in that: The organic dicarboxylic acid is selected from one or more of sebacic acid, oxalic acid, glutamic acid, and aspartic acid.

6. The flaw detection coupling fluid according to claim 1, characterized in that: The organic dicarboxylic acid is selected from aspartic acid and sebacic acid in a mass ratio of 1:(2-3).

7. The flaw detection coupling fluid according to claim 1, characterized in that: The organic sodium salt is selected from sodium benzoate and sodium methylsilicate in a mass ratio of 1:(1.2-1.5).

8. The flaw detection coupling fluid according to claim 1, characterized in that: The diethylene glycol was obtained after pretreatment using the following method: Dissolve 2-5 parts by weight of microcrystalline cellulose in 3-5 parts of N,N-dimethylformamide, then add 3-5 parts of castor oil and 1-3 parts of stearic acid, mix, then add 10-20 parts of diethylene glycol, mix, and obtain pretreated diethylene glycol.

9. A method for preparing the flaw detection coupling fluid as described in any one of claims 1-8, characterized in that: Includes the following steps: Water and ethylene glycol are mixed and prepared, then an organic carboxylic acid type coolant composite functional agent and a rust inhibitor are added, stirred at room temperature, then an antifoaming agent and dye are added, stirred, filtered, and filled to obtain the flaw detection coupling fluid.

Images