Environment-friendly dye penetrant inspection agent used in low-temperature environment and preparation method of environment-friendly dye penetrant inspection agent

Abstract

The invention relates to the technical field of surface defect detection, and discloses an environment-friendly dye penetrant flaw detection agent used in a low-temperature environment, which comprises the following components in percentage by weight: 60-75% of penetrant base solution, 45-55% of low-temperature environment-friendly solvent and 10-15% of low-temperature solubilizer; 7-12% of a coloring agent; the invention further discloses a preparation method of the environment-friendly dye penetrant flaw detection agent used in the low-temperature environment. The preparation method comprises the following steps: S1, mixing the low-temperature environment-friendly solvent and the low-temperature solubilizer, and stirring to form a penetrant base solution; and S2, dissolving the fluorescent dye and the azo dye in the penetrant base solution. By optimizing the formula and the process, the excellent fluidity, permeability and developing effect of the flaw detection agent at low temperature are realized, the microcracks are clear, and the developing contrast ratio is high; meanwhile, the VOC content is reduced, the environment-friendly performance is excellent, the stability of long-term storage is high, and the method is suitable for high-precision detection in an extreme environment.

Description

Technical Field

[0001] The invention relates to the technical field of surface defect detection, in particular to an environmentally friendly colored penetrant flaw detection agent used in a low-temperature environment and a preparation method thereof. Background Art

[0002] In the field of industrial nondestructive testing, penetrant flaw detection agents are widely used testing materials, which help testers find microcracks or other defects on the surface of materials through processes such as penetration and development. However, with the increasing complexity of the application environment, especially in low temperature, extreme environment and scenes with high environmental protection requirements, the existing penetrant flaw detection agent technology has shown some unavoidable limitations and it is difficult to fully meet the actual needs of modern industrial testing.

[0003] In low-temperature environments, the penetration and flow properties of flaw detection agents are key indicators that affect detection accuracy. The flaw detection agents in the prior art usually use benzene, lipid or alcohol solvents as the base liquid. Although these solvents can maintain good fluidity under normal temperature conditions, in low-temperature environments (such as below -50°C), the solvent viscosity will increase significantly, and even freeze. This performance degradation leads to reduced spreading of the flaw detection agent on the crack surface and insufficient penetration depth inside the crack, especially for microcracks with a width of less than 0.1 mm. The problem of insufficient penetration is particularly prominent. In addition, the existing flaw detection agents lack special solubilizers for low-temperature environments, and the solubility of many solubilizers decreases at low temperatures, resulting in further deterioration of the penetration effect of the flaw detection agent. This significantly limits the application of existing flaw detection agents in low-temperature scenarios such as aerospace and polar engineering.

[0004] In terms of development performance, existing penetrant flaw detection agents also have obvious deficiencies. The function of the developer is to cover the crack surface with developer powder to form a defect display area visible to the naked eye. However, the powder particle size distribution of many traditional developers is uneven, or they have not been fully dispersed, which easily forms accumulation or blank areas on the crack surface, resulting in incomplete coverage of the developer layer. In addition, the volatility of commonly used solvents in existing developers is not well controlled, the evaporation rate of the solvent on the crack surface is uneven, and the adhesion of the developer particles is insufficient, which further weakens the crack development effect. Especially in precision industrial equipment, when the crack width and depth are small, the resolution and development clarity of the developer are difficult to meet the actual detection needs, limiting the widespread application of flaw detection agents in the field of high-precision non-destructive testing.

[0005] Environmental performance has gradually become an important direction for the development of penetrant flaw detection agent technology. The organic solvents used in existing flaw detection agents are mainly benzene and highly volatile alcohols. While these solvents improve the penetration performance, they also bring about higher volatile organic compound (VOC) emission problems. The typical VOC content often reaches 100-300 mg / L, which is much higher than the requirements of environmental protection regulations. In addition, the penetration aids or dispersants added to some flaw detection agents contain non-degradable ingredients, such as phosphorus compounds, which cause long-term pollution to the environment. Although some technologies attempt to reduce VOC by reducing the amount of solvent used, this method often comes at the cost of reduced performance, and it is difficult to achieve a balance between performance and environmental protection.

[0006] In the preparation process of flaw detection agents, traditional technologies also have some bottlenecks. For example, the dispersion process of developers mainly relies on mechanical stirring, and lacks more efficient dispersion technology (such as ultrasonic treatment), resulting in a wide distribution of developer powder particle size and unstable development performance. In addition, many flaw detection agents are not vacuum degassed or stabilized in the preparation process, which makes residual bubbles and particle agglomeration in the flaw detection agent more common, further affecting the permeability and development effect of the flaw detection agent. The shortcomings of this preparation process not only limit the improvement of the performance of the flaw detection agent, but also affect its consistency and reliability to a certain extent.

[0007] In summary, existing penetrant flaw detection agents have significant limitations in low temperature adaptability, development performance and environmental performance, and the backward preparation process has further exacerbated the problems in their application. Especially in scenarios that require high precision and environmental protection, traditional flaw detection agent technology is difficult to meet actual needs, and it is urgent to solve these technical bottlenecks through formulation optimization and process innovation. Summary of the invention

[0008] In view of the deficiencies in the prior art, the present invention provides an environmentally friendly colored penetrant flaw detection agent for use in a low-temperature environment and a preparation method thereof, which solves the problems of insufficient fluidity and permeability, poor developing performance, poor environmental protection and poor storage stability of the existing penetrant flaw detection agents in a low-temperature environment.

[0009] To achieve the above purpose, the present invention is implemented by the following technical scheme: an environmentally friendly colored penetrant flaw detection agent used in a low temperature environment, comprising the following components by weight percentage: Penetrant base liquid, accounting for 60-75%, including 45-55% of low-temperature environmentally friendly solvent and 10-15% of low-temperature solubilizer; Colorants, 7-12%, including fluorescent dyes 4-6% and azo dyes 3-5%; Penetration enhancers, accounting for 5-10%; Dispersants, 3-6%; Developer, accounting for 15-30%, including 10-20% of nano developer powder and 5-10% of developer solvent; Functional additives, accounting for 0.5-2%.

[0010] Preferably, the low-temperature environmentally friendly solvent is isopropyl alcohol ester or propylene glycol fatty acid ester, and the low-temperature solubilizing agent is polyethylene glycol, 1,2-butylene glycol or glycerol.

[0011] Preferably, the fluorescent dye is rhodamine B or 4-methylumbelliferone, and the azo dye is azobenzene or curcumin.

[0012] Preferably, the penetration aid is alkyl glycoside, disodium sulfosuccinate or alkyl polyether sulfonate.

[0013] Preferably, the dispersant is polysorbate 80 or ethoxylated fatty alcohol.

[0014] Preferably, the nano developer powder is titanium dioxide or silicon dioxide with a particle size of 10-30 nm, and the developer solvent is a mixture of deionized water and ethanol in a mixing ratio of 2:1.

[0015] A method for preparing an environmentally friendly colored penetrant flaw detector for use in a low-temperature environment, which is used to prepare the environmentally friendly colored penetrant flaw detector for use in a low-temperature environment as described above, comprises the following steps: S1. Mixing a low-temperature environmentally friendly solvent and a low-temperature solubilizer, and stirring to form a penetrant base liquid; S2, dissolving the fluorescent dye and the azo dye in the penetrant base liquid to form a colorant solution; S3, mixing the colorant solution, the penetration aid and the dispersant, and stirring evenly; S4, dispersing nano developer powder in a developer solvent to form a developer; S5, mixing the mixture of step S3 with a developer, performing vacuum degassing treatment, and standing to stabilize after the degassing is completed; S6. Packing to obtain the finished flaw detection agent.

[0016] Preferably, in step S1, the stirring temperature of the penetrant base liquid is 30-40° C., the stirring speed is 300-500 rpm, and the stirring time is 15-20 min.

[0017] Preferably, the vacuum degree of vacuum degassing in step S5 is -0.08 to -0.1 MPa, the degassing temperature is 30-40°C, the degassing time is 20-30 min, and the specific conditions of the stabilization treatment in step S5 are: The degassed mixture was placed at 5-10°C. The stabilization time is 12-24h.

[0018] The present invention provides an environmentally friendly colored penetrant flaw detection agent for use in a low temperature environment and a preparation method thereof. It has the following beneficial effects: 1. The present invention adopts an optimized combination of low-temperature environmentally friendly solvents and low-temperature solubilizers to ensure that the flaw detection agent still maintains good fluidity and permeability in an extreme environment of -50°C. Compared with the problem of detection failure caused by solvent crystallization or insufficient fluidity in the prior art, the technical defect that the flaw detection agent is difficult to use normally in a low-temperature environment is solved.

[0019] 2. The present invention significantly improves the color rendering and crack contrast through the combined use of fluorescent dyes and azo dyes, and can clearly present the depth and distribution of microcracks. Compared with the prior art that only uses a single dye with unstable color rendering or insufficient contrast, the crack color rendering quality and detection accuracy are significantly improved.

[0020] 3. The present invention uses environmentally friendly penetration aids and dispersants, which greatly reduces the volatile organic matter content of the flaw detection agent, while improving the uniformity of dye dispersion and penetration. Compared with traditional high-volatile solvent-type flaw detection agents, it solves the hidden dangers of environmental pollution and operator health and safety, and takes into account both green environmental protection requirements and industrial performance.

[0021] 4. The present invention adopts the coordinated design of nano developer powder and developer solvent in the preparation of developer, combined with vacuum degassing and stabilization treatment, which greatly improves the development uniformity and crack visualization effect. Compared with the technical solutions in the prior art in which the developer particles are easy to agglomerate and the coverage is incomplete, it effectively overcomes the problems of unclear development and low detection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the method flow of the present invention. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the specification of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Please see attached Figure 1 The embodiment of the present invention provides an environmentally friendly colored penetrant flaw detection agent for use in a low temperature environment, which comprises the following components by weight percentage: Penetrant base liquid, accounting for 60-75%, including 45-55% of low-temperature environmentally friendly solvent and 10-15% of low-temperature solubilizer; Colorants, 7-12%, including fluorescent dyes 4-6% and azo dyes 3-5%; Penetration enhancers, accounting for 5-10%; Dispersants, 3-6%; Developer, accounting for 15-30%, including 10-20% of nano developer powder and 5-10% of developer solvent; Functional additives, accounting for 0.5-2%.

[0025] The low-temperature environmentally friendly solvent is isopropyl alcohol ester or propylene glycol fatty acid ester, and the low-temperature solubilizer is polyethylene glycol, 1,2-butylene glycol or glycerol.

[0026] The fluorescent dye is rhodamine B or 4-methylumbelliferone, and the azo dye is azobenzene or curcumin.

[0027] The penetration aid is alkyl glycoside, disodium sulfosuccinate or alkyl polyether sulfonate.

[0028] The dispersant is polysorbate 80 or ethoxylated fatty alcohol.

[0029] The nano developer powder is titanium dioxide or silicon dioxide with a particle size of 10-30 nm, and the developer solvent is a mixture of deionized water and ethanol in a mixing ratio of 2:1.

[0030] A method for preparing an environmentally friendly colored penetrant flaw detector for use in a low-temperature environment, which is used to prepare an environmentally friendly colored penetrant flaw detector for use in a low-temperature environment, comprises the following steps: S1. Mixing a low-temperature environmentally friendly solvent and a low-temperature solubilizer, and stirring to form a penetrant base liquid; S2, dissolving the fluorescent dye and the azo dye in the penetrant base liquid to form a colorant solution; S3, mixing the colorant solution, the penetration aid and the dispersant, and stirring evenly; S4, dispersing nano developer powder in a developer solvent to form a developer; S5, mixing the mixture of step S3 with a developer, performing vacuum degassing treatment, and standing to stabilize after the degassing is completed; S6. Packing to obtain the finished flaw detection agent.

[0031] In step S1, the stirring temperature of the penetrant base liquid is 30-40° C., the stirring speed is 300-500 rpm, and the stirring time is 15-20 min.

[0032] The vacuum degree of vacuum degassing in step S5 is -0.08 to -0.1 MPa, the degassing temperature is 30-40°C, the degassing time is 20-30 min, and the specific conditions of the stabilization treatment in step S5 are: The degassed mixture was placed at 5-10°C. The stabilization time is 12-24h.

[0033] Example 1: An environmentally friendly colored penetrant flaw detector for ultra-low temperature aviation component inspection Specific preparation steps: Preparation of base liquid: Add 45 g of isopropyl alcohol ester and 10 g of polyethylene glycol (PEG-400) into a stirring kettle and set the stirring temperature to 35° C. Stir at 400 rpm for 20 min until a uniform transparent liquid is formed.

[0034] Colorant dissolution: Slowly add 5g of rhodamine B and 3g of azobenzene dye to the prepared base liquid. Ultrasonic oscillation assists dissolution (frequency 25kHz) and the time is set to 12 minutes. After no particles are precipitated, the colorant solution is obtained.

[0035] Component mixing: 5g of alkyl glycoside permeation enhancer and 4g of polysorbate-80 dispersant were added to the above colorant solution in sequence. The stirring speed was increased to 600 rpm and the mixing was continued for 15 minutes to make the system uniform.

[0036] Developer preparation: 15 g of silicon dioxide powder with a particle size of 20 nm was slowly added into a developer solvent consisting of 15 g of deionized water and 7.5 g of ethanol, first dispersed at a low speed (200 rpm) for 20 min, and then ultrasonically treated (30 kHz, 10 min) to form a developer.

[0037] Mixing and vacuum degassing: Slowly add the developer to the aforementioned colorant mixture, keep stirring at 600 rpm for 10 minutes, and then transfer to the vacuum degassing equipment. The vacuum degree is set to -0.1 MPa, the temperature is maintained at 40°C, and the degassing time is 30 minutes.

[0038] Stabilization: After degassing, place the flaw detector in a cold storage environment (7°C) for 20 hours to complete the stabilization process. After filling and sealing, the finished flaw detector is completed.

[0039] Example 2: A low temperature flaw detector suitable for crack detection in polar engineering pipelines Specific preparation steps: Base liquid mixing: weigh 50g of propylene glycol fatty acid ester and 12g of 1,2-butanediol in proportion, add into a thermostatic stirring kettle, and control the stirring temperature at 30°C. Set the stirring speed to 350rpm and mix for 15min.

[0040] Colorant preparation: 4.5 g 4-methylumbelliferone and 3.5 g curcumin powder were added to the base liquid, pre-mixed using a magnetic stirrer, and then subjected to ultrasonic dispersion treatment (frequency 28 kHz, duration 15 min) to form a uniform colorant liquid.

[0041] Addition of penetration aid and dispersant: 6 g of disodium sulfosuccinate and 3.5 g of ethoxylated fatty alcohol solution were added to the colorant in sequence, and treated at 800 rpm for 10 min using a high shear stirring device.

[0042] Preparation of developer: 12 g of developer powder (10 nm titanium dioxide) was slowly added to a mixture of 8 g of deionized water and 4 g of ethanol, stirred at a low speed for 20 min, and then ultrasonically dispersed (frequency 27 kHz) for 12 min to prepare the developer.

[0043] Vacuum degassing: Move the mixed solution into a vacuum device, set the temperature to 35°C, maintain the vacuum degree at -0.09MPa, and degassing time for 25min. During the process, maintain the stirring speed at 500rpm to ensure uniform mixing.

[0044] Stabilized storage: Refrigerate the degassed flaw detection agent (at 5°C) for 24 hours before filling to obtain the finished product.

[0045] Example 3: An environmentally friendly colored penetrant flaw detection agent for low-temperature industrial equipment Specific preparation steps: Base liquid preparation: Weigh 48 g of isopropyl alcohol ester and 11 g of propylene glycol, add into a stirring kettle, heat to 38°C, and maintain stirring at 350 rpm for 15 min.

[0046] Dissolve the colorant: Add 6g of rhodamine B and 3g of azobenzene dye to the base liquid. Use ultrasonic equipment to treat, set the frequency to 30kHz, and the time is 12min.

[0047] Dispersion and penetration-enhancing treatment: Add 5 g of alkyl glycoside penetration-enhancing agent and 3.5 g of polysorbate 80 dispersant, and treat with variable speed stirring (500-800 rpm) for 10 min.

[0048] Preparation of developer: 20 g of silica powder was added to 9 g of deionized water and 4 g of ethanol, stirred at a low speed for 30 min, and then treated with an ultrasonic dispersion device (frequency 35 kHz) for 8 min to form a developer.

[0049] Mixing and degassing: Slowly add the developer to the colorant mixture, keep the stirring speed at 600rpm, mix for 10 minutes, and then transfer to the vacuum degassing equipment. The degassing temperature is set to 40℃, the vacuum degree is -0.1MPa, and the treatment is 30 minutes.

[0050] Standing and filling: Place the degassed flaw detection agent in a 10℃ environment for 12 hours, and then fill and seal it after it stabilizes.

[0051] Example 4: A special flaw detection agent for crack detection of low-temperature nuclear power equipment Specific preparation steps: Mix base liquid: Mix 50g of propylene glycol fatty acid ester with 10g of polyethylene glycol-400, control the stirring temperature at 40°C, set the speed to 400rpm, and continue for 20min.

[0052] Addition of colorant: Add 5.5g 4-methylumbelliferone and 3g curcumin to the base liquid. Use high-frequency ultrasonic dispersion at a frequency of 28kHz for 15 minutes to ensure complete dissolution.

[0053] Dispersion and penetration treatment: add 6g of disodium sulfosuccinate and 4g of ethoxylated fatty alcohol to the colorant mixture, stir at 600rpm, and set the stirring time to 12min.

[0054] Preparation of developer: 15 g of titanium dioxide powder (particle size 15 nm) was added with 10 g of developer solvent (mixture of deionized water and ethanol), stirred at low speed for 25 min, and then ultrasonically treated (frequency 30 kHz) for 10 min to form a developer.

[0055] Vacuum degassing and stabilization: Add the developer and colorant mixture into the vacuum equipment, set the vacuum degree to -0.08MPa, maintain the temperature at 35℃, and process for 30min. After degassing, place the flaw detection agent in an environment of 8℃ to stabilize for 24h.

[0056] Comparative Example 1 (corresponding to Example 1): Preparation process: Preparation of base liquid: Add 45g of isopropyl alcohol ester and 5g of PEG-200 into a stirring kettle, control the stirring temperature at 30°C, set the stirring speed to 400rpm, and stir for 15min.

[0057] Colorant dissolution: 3g of rhodamine B and 6g of azobenzene dye were added to the base liquid and pre-mixed by magnetic stirring. Ultrasonic oscillation was not used to assist dissolution, and the stirring time was only extended to 30 minutes.

[0058] Component mixing: Add 4 g disodium sulfosuccinate and 5 g polysorbate-80, increase the stirring speed to 800 rpm, and set the mixing time to 8 min.

[0059] Developer preparation: 10 g of silicon dioxide powder with a particle size of 30 nm was directly mixed with 10 g of deionized water at a stirring speed of 200 rpm for 15 min. No ultrasonic dispersion treatment was performed.

[0060] Vacuum degassing: transfer the mixture to a vacuum device, set the vacuum degree to -0.05 MPa, maintain the temperature at 25 °C, and degassing for 20 min.

[0061] Standing and filling: The degassed flaw detection agent is placed in a 15℃ environment for 12 hours before filling and sealing.

[0062] Comparative Example 2 (corresponding to Example 2): Preparation process: Base liquid mixing: Weigh 55g of propylene glycol fatty acid ester and 8g of propylene glycol, add into a constant temperature stirring kettle, set the stirring temperature to 25°C, the speed to 300rpm, and continue stirring for 10min.

[0063] Colorant dissolution: Add 4g 4-methylumbelliferone and 3g curcumin powder to the base liquid. Dissolve by mechanical stirring without ultrasonic treatment, and extend the stirring time to 20min.

[0064] Addition of penetration aid and dispersant: 3 g of alkyl glycoside penetration aid and 2 g of ethoxylated fatty alcohol were added to the mixture, and the stirring speed was set to 400 rpm for 10 min.

[0065] Preparation of developer: 15 g of developer powder (titanium dioxide with a particle size of 40 nm) was directly added to 12 g of deionized water, with a stirring speed of 200 rpm for 15 min. No ethanol mixed solvent was used.

[0066] Vacuum degassing: The mixture was placed in a vacuum degassing device, the vacuum degree was set to -0.07 MPa, the temperature was set to 28 °C, and the degassing time was 15 min.

[0067] Stabilization treatment: Place the degassed flaw detection agent at room temperature (20°C) for 6 hours and then directly fill it.

[0068] Comparative Example 3 (corresponding to Example 3): Preparation process: Base liquid preparation: 50 g of isopropyl alcohol ester and 8 g of propylene glycol were added into a stirring kettle, the stirring temperature was controlled at 25°C, the stirring speed was set to 300 rpm, and the mixing time was 10 min.

[0069] Dissolving colorant: Add 7g of rhodamine B and 2g of azobenzene dye to the base liquid and treat it by mechanical stirring for 20min without ultrasonic treatment.

[0070] Addition of penetration aid and dispersant: Add 6 g of alkyl glycoside and 2 g of polysorbate-80, set the mixing speed to 500 rpm, and mix for 5 min.

[0071] Developer preparation: 20 g of developer powder (silicon dioxide with a particle size of 50 nm) was added to 20 g of deionized water, and the stirring speed was set to 300 rpm for 15 min. No ultrasonic dispersion was performed, and no ethanol mixture was used.

[0072] Vacuum degassing: In the vacuum equipment, the vacuum degree is set to -0.06MPa, the degassing temperature is 30℃, and the degassing time is 20min.

[0073] Static treatment: Place the flaw detection agent in a room temperature environment and let it stand for 10 hours before filling.

[0074] Comparative Example 4 (corresponding to Example 4): Preparation process: Mixed base liquid: Add 60g propylene glycol fatty acid ester and 5g PEG-200 into a stirring kettle, control the temperature at 25°C, stir at 350rpm, and stir for 10min.

[0075] Colorant dissolution: 6 g 4-methylumbelliferone and 2 g curcumin were added to the base liquid, and conventional magnetic stirring was used. The time was set to 25 min, and ultrasonic dispersion was not used.

[0076] Penetration aid and dispersant addition: Add 4g disodium sulfosuccinate and 3g ethoxylated fatty alcohol, increase stirring speed to 400rpm, and mix for 15min.

[0077] Preparation of developer: 15 g of developer powder (titanium dioxide with a particle size of 40 nm) was directly mixed with 10 g of deionized water at a stirring speed of 200 rpm, without adding ethanol, and the stirring time was 20 min.

[0078] Vacuum degassing: transfer the mixed solution to a vacuum device, set the temperature to 28°C, the vacuum degree to -0.07MPa, and the degassing time to 15min.

[0079] Stabilization treatment: Place the flaw detection agent at room temperature (20°C) and let it stand for 6 hours before directly filling and sealing.

[0080] Experiment 1: Fluidity test of flaw detection agent in low temperature environment Experimental description: Experimental purpose: To test the flowability of the flaw detection agent under low temperature conditions (-50°C) and verify whether the flaw detection agent of the present invention can maintain excellent fluidity.

[0081] Experimental steps: Sample preparation: Take 50 mL of flaw detection agent sample from Example 1, Example 2 and Comparative Example 1, Comparative Example 2 respectively, pour it into a transparent glass tube with a diameter of 10 mm and a length of 150 mm, and seal it with a rubber stopper.

[0082] Low temperature constant temperature treatment: Place the prepared glass tube sample in a low temperature constant temperature box and set the temperature to -50°C. Let the sample stand for 1 hour to ensure that it reaches the set temperature completely.

[0083] Liquidity test: (1) Take out the glass tube from the low temperature constant temperature box and quickly fix it on a bracket with an inclined angle of 30°.

[0084] (2) Record the distance (mm) that the flaw detection agent sample flows in the inclined glass tube for 10 seconds.

[0085] (3) Repeat the above steps three times and take the average value of each sample as the final result.

[0086] Note: During the test, the glass tube was protected from heat to ensure that the sample remained at a low temperature.

[0087] Use a millimeter ruler when recording flow distance to ensure accurate measurements.

[0088] The sample must be kept free of bubbles to avoid bias in the test results.

[0089] Experimental data: Table 1: Fluidity test results of flaw detection agent at -50℃ sample Test 1(mm) Test 2(mm) Test 3 (mm) Average value(mm) Example 1 67 72 69 69.3 Example 2 64 66 65 65.0 Comparative Example 1 42 45 43 43.3 Comparative Example 2 38 39 40 39.0 Experimental summary: The flaw detection agents in Example 1 and Example 2 show good flow properties under low temperature conditions. In the inclined glass tube, they can flow quickly and smoothly over a long distance without obvious sticking or intermittent phenomena. This is due to the selection of low-temperature environmentally friendly solvents (such as isopropyl alcohol esters and propylene glycol fatty acid esters), which can remain liquid even in extreme environments of -50°C. At the same time, the addition of PEG-400 or glycerol effectively reduces the viscosity of the system, making the flaw detection agent have excellent low-temperature fluidity.

[0090] In contrast, the fluidity of Comparative Examples 1 and 2 in low temperature environments is significantly limited. In Comparative Example 1, a low molecular weight solubilizer (PEG-200) is used, which has insufficient viscosity adjustment ability, resulting in a certain viscosity of the flaw detection agent at low temperatures. In addition, the proportion of propylene glycol in Comparative Example 2 is low, resulting in the base liquid being partially viscous at low temperatures and unable to meet the requirements of crack coverage. This shows that the molecular structure and addition ratio of the solubilizer are crucial to the low temperature performance of the flaw detection agent.

[0091] The results of this experiment also verified the mechanism of action of the penetration agent. The reasonable ratio of the penetration agent in the embodiment reduces the surface tension, making the flaw detection agent spread and flow more smoothly on the inclined pipe wall. However, the penetration agent in the comparative example is not added enough, resulting in weakened fluidity. This difference can be intuitively reflected from the flow distance data of the test results. The fluidity of the flaw detection agent in a low temperature environment directly affects its ability to penetrate cracks, so the formula optimization of the present invention is of great significance for the practicality of low-temperature non-destructive testing.

[0092] Experiment 2: Microcrack penetration performance test Experimental description: Experimental purpose: To verify the penetration performance of the flaw detection agent of the present invention on microcracks under low temperature conditions, and to focus on comparing the development effects of the flaw detection agents of the embodiment and the comparative example on artificial crack test pieces.

[0093] Experimental steps: Preparation of artificial crack test piece: Use ASTME165 standard artificial crack test piece, set the crack width to 0.05mm, and the crack depth to 0.1mm. After cleaning the test piece, wipe the surface with anhydrous ethanol to remove oil and ensure that there is no impurity residue in the crack.

[0094] Sample selection: Select the flaw detection agents of Example 1, Example 2, Example 3, and Comparative Example 1, Comparative Example 2, and Comparative Example 3. Prepare 3 test pieces for each flaw detection agent for testing to ensure experimental repeatability.

[0095] Low temperature treatment: Place all test pieces in a low temperature constant temperature box, set the temperature to -40℃, and keep the temperature constant for 1 hour to simulate the testing environment under extremely low temperature.

[0096] Flaw detection agent coating: After taking out the test piece from the constant temperature box, immediately apply the flaw detection agent sample on the surface of the test piece to ensure that the crack area is covered. Keep the static penetration time for 1 minute.

[0097] Surface cleaning and development: After penetration, wipe off the excess flaw detection agent on the surface with a dry cloth. Then spray the developer, and set the development time to 2 minutes to ensure that the crack area is clearly developed.

[0098] Observation of crack development effect: Use a high-definition digital camera (resolution set to 300dpi) to take crack development images and record the length of crack development (mm). Each sample is tested 3 times and the average value is taken.

[0099] Note: The entire operation process should be completed quickly in a low temperature environment to avoid heating of the test piece.

[0100] The developer needs to be sprayed evenly during the development process to avoid developer accumulation affecting the crack development effect.

[0101] Experimental data: Table 2: Test results of microcrack development length of flaw detection agent at -40℃ sample Test 1(mm) Test 2(mm) Test 3 (mm) Average value(mm) Example 1 0.92 0.95 0.94 0.94 Example 2 0.90 0.88 0.91 0.90 Example 3 0.89 0.86 0.90 0.88 Comparative Example 1 0.63 0.66 0.62 0.64 Comparative Example 2 0.57 0.59 0.60 0.59 Comparative Example 3 0.65 0.68 0.67 0.67 Experimental summary: The flaw detector of the present invention has shown its advantages in the low-temperature crack penetration performance test, especially the performance of Example 1 and Example 2 is more outstanding. Its ability to penetrate into the crack is obviously stronger, and the development length is close to the full length of the crack. The two solubilizers, PEG-400 and propylene glycol, play a key role in effectively reducing the viscosity of the liquid at low temperatures, allowing the flaw detector to quickly penetrate into cracks with a width of only 0.05 mm. Through the interfacial effect of the penetration agent, the flaw detector can quickly wet the surface of the test piece, showing a more uniform development effect.

[0102] The performance of the comparative samples was obviously limited. In particular, in comparative example 2, due to the insufficient propylene glycol content, the viscosity increased significantly at low temperatures, and the flow was slow when penetrating the cracks, resulting in incomplete crack development. At the same time, the low molecular weight solubilizer PEG-200 used in comparative example 1 had weak intermolecular forces, resulting in the inability of the solvent system to maintain uniformity at low temperatures. As a result, the coverage depth of the flaw detection agent in the crack was affected, and the crack development length was insufficient.

[0103] The dispersion state of the developer is also the key to the results. Ultrasonic treatment is used in the embodiment to make the nano developer powder evenly dispersed and better adhere to the crack area. However, the developer powder particle size of Comparative Example 3 is too large and not fully dispersed, so the developer has a weak ability to adhere to the crack surface, and the development effect is therefore limited to a certain extent. This shows that the formula design of the flaw detection agent of the present invention has significant advantages in both low-temperature penetration and development.

[0104] Experiment 3: Development performance test Experimental description: Experimental purpose: To test the developing performance of the flaw detection agent, including the clarity and contrast of the crack developing area, and to verify the advantages of the present invention in developing effect.

[0105] Experimental steps: Preparation of artificial crack test piece: Use standard artificial crack test piece (ASTME165), with crack width of 0.08mm and depth of 0.15mm. After cleaning the test piece, wipe the surface with anhydrous ethanol to ensure that there are no impurities and oil stains on the crack and the test piece surface.

[0106] Sample preparation: Take the flaw detection agent samples from Example 1, Example 4 and Comparative Example 1, Comparative Example 4 respectively, and prepare 3 test pieces for each flaw detection agent for testing.

[0107] Flaw detection agent coating: Apply the flaw detection agent evenly on the crack surface of the test piece and let it stand for 2 minutes to ensure that the flaw detection agent penetrates into the crack.

[0108] Surface cleaning and development: Use a clean soft cloth to gently wipe off the excess flaw detection agent on the surface of the test piece, ensuring that the flaw detection agent in the crack is not disturbed. Then use the developer to evenly spray the crack surface, the spraying distance is 15cm, and the development time is 2min.

[0109] Image recording and analysis: Use a high-definition digital camera (resolution 300dpi) to photograph the crack development area. Import the image into the development analysis software, and use the software to calculate the contrast (ΔC) of the crack development area.

[0110] Repeat the experiment: Repeat the test for each flaw detection agent 3 times and take the average value as the final contrast result.

[0111] Note: The developer should be sprayed evenly to avoid excessive accumulation or insufficient spraying of developer.

[0112] The developing time is strictly controlled within 2 minutes to prevent the developing effect from diffusing and blurring due to too long a time.

[0113] Experimental data: Table 3: Crack development contrast test results of flaw detection agent Sample test 1 (ΔC) Test 2 (ΔC) Test 3 (ΔC) Average value (ΔC) Example 1 0.88 0.91 0.90 0.90 Example 4 0.83 0.85 0.87 0.85 Comparative Example 1 0.62 0.65 0.63 0.63 Comparative Example 4 0.59 0.60 0.58 0.59 Experimental summary: The flaw detection agent of Example 1 showed significant advantages in the development performance test. The development contrast ΔC value reached 0.90, and the visual difference between the crack area and the background area was very obvious. Through the preferred developer formula, the developer powder was evenly dispersed after ultrasonic treatment, and the particle size was maintained in the range of 10-30nm. These powders can form a dense development covering layer on the crack surface, effectively enhancing the clarity of crack development. At the same time, the reasonable proportion of the penetration aid enables the flaw detection agent to penetrate into the crack more evenly, providing a sufficient development basis for the developer.

[0114] The test results of the comparative examples are quite different. The contrast ratio of comparative example 1 is only 0.63, the development effect is unclear, and the color development of the crack area is uneven. This is because its low molecular weight solubilizer (PEG-200) shows instability in a low temperature environment, and the viscosity of the flaw detection agent system is high, which cannot completely penetrate the crack. The developer powder is not dispersible enough, resulting in obvious particle accumulation when covering the crack, which further weakens the development effect.

[0115] Another key reason for the low contrast ratio of the developer is the particle size of the developer. The developer powder of Comparative Example 4 has not been treated with ultrasound, and the particle size is large and unevenly distributed, resulting in poor coverage of the crack development area. The choice of developer solvent also shows problems. The developer solvent that is not mixed with ethanol cannot evaporate quickly on the crack surface, the adhesion of the developer powder decreases, and the boundary of the development area is blurred. Obviously, the developer formulation and process optimization in the present invention are crucial in actual detection.

[0116] Experiment 4: Volatile organic compound (VOC) content test Experimental description: Experimental purpose: To test the volatile organic compound (VOC) content of the flaw detection agent, verify the advantages of the formula of the present invention in environmental performance, and compare it with the comparative example.

[0117] Experimental steps: Sample preparation: Take 50 mL of flaw detection agent samples from Example 1, Example 2, Example 3 and Comparative Example 1 and Comparative Example 2. All samples are stored in sealed containers to prevent external contamination.

[0118] Testing instruments: A gas chromatography-mass spectrometer (GC-MS) was used, equipped with a polar capillary column and a FID detector. Instrument parameters: Initial temperature: 50°C, heating rate: 10°C / min, final temperature: 220°C; Carrier gas flow rate: 1 mL / min, injection port temperature: 250 °C; Injection volume: 2 μL.

[0119] Testing process: (1) Place the flaw detection agent sample in a sealed glass container and leave it at room temperature for 24 hours before sampling; (2) 2 μL of the sample was extracted by syringe and directly injected into the gas chromatograph; (3) Record the volatile organic compound content in the sample, with the data expressed in mg / L; (4) Each sample was tested three times and the average value was taken.

[0120] Data processing: The content of each component in the sample is calculated by comparing with the standard curve, and finally the total VOC content is obtained.

[0121] Note: During operation, avoid exposing the sample to air to prevent volatile losses.

[0122] A blank calibration is required before the instrument is injected to ensure the accuracy of the results.

[0123] Experimental data: Table 4: Volatile organic compound (VOC) content test results of flaw detection agents sample Test 1 (mg / L) Test 2 (mg / L) Test 3 (mg / L) Average value (mg / L) Example 1 41 45 43 43.0 Example 2 48 46 50 48.0 Example 3 52 55 53 53.3 Comparative Example 1 89 92 87 89.3 Comparative Example 2 108 105 110 107.7 Experimental summary: The experimental results show that the volatile organic content of the flaw detection agents of Examples 1 and 2 is significantly lower than that of the comparative example. The VOC content of Example 1 is 43 mg / L, which is much lower than the industry standard of 50 mg / L. This excellent performance is mainly due to the use of environmentally friendly low-temperature solvents (such as isopropyl alcohol esters and propylene glycol fatty acid esters). They have a low vapor pressure and can remain stable even in an open environment, avoiding the release of high volatile organic compounds. In addition, the selection of penetration aids and dispersants (such as polysorbate-80 and alkyl glycosides) also plays a key role in reducing the VOC content. These ingredients themselves have low toxicity and low volatility, which further improves the environmental performance of the flaw detection agent.

[0124] The VOC content of Comparative Example 1 is significantly higher, reaching 89 mg / L. This is related to the PEG-200 solubilizer selected. Although low molecular weight solubilizers can improve solubility, their high vapor pressure leads to an increase in the release of volatile organic compounds during the use and storage of the flaw detection agent. In addition, ethanol is not introduced into the developing solvent of Comparative Example 1, which may cause the instability of the solvent system and aggravate the release of VOCs.

[0125] Although the VOC content in Example 3 is slightly higher, it is still controlled at 53.3 mg / L, which is lower than 107.7 mg / L in Comparative Example 2. This shows that the developer formula has a significant impact on the VOC content. Comparative Example 2 does not use developer powder with excellent dispersibility, and lacks a reasonable ratio adjustment of ethanol and deionized water, and the volatility problem of the developer solvent is more prominent. Overall, the present invention successfully reduces VOC emissions by optimizing the selection of solvents and additives in the formula design, providing a reliable solution for environmental protection applications.

[0126] Experiment 5: Storage stability test Experimental description: Experimental purpose: To test the physical stability and developing performance of the flaw detection agent under different storage conditions, and to verify the storage adaptability and reliability of the flaw detection agent of the present invention.

[0127] Experimental steps: Sample preparation: Take 50 mL of each flaw detection agent sample from Example 1, Example 3, Comparative Example 3, and Comparative Example 4, respectively, put them into a transparent sealed container, and seal them for later use.

[0128] Storage condition settings: The samples were placed in the following two storage environments: Low temperature environment: the temperature is set to -10°C and the storage time is 30 days; Room temperature environment: The temperature is set to 25°C and the storage time is 30 days.

[0129] Post-storage testing: (1) After the 30-day storage period, check whether the samples have stratification, crystallization, precipitation, etc., and record the observation results; (2) The stored flaw detection agent was used for standard artificial crack test (crack width of 0.05 mm, depth of 0.1 mm), and the development process was the same as that of Experiment 3; (3) Record the crack development contrast (ΔC) and the uniformity of the development area, and take a crack development image.

[0130] Data recording and analysis: The physical stability of the sample (whether it is stratified, crystallized, etc.) is marked as "good / bad"; the development performance is represented by the development contrast (ΔC). Each sample is tested 3 times and the average value is taken as the final result.

[0131] Note: After the sample is taken out from the storage environment, it should be tested promptly to avoid the results being affected by external temperature changes.

[0132] The development performance test must be carried out strictly in accordance with the standard crack test piece to ensure the comparability of the test results.

[0133] Experimental data: Table 5: Test results of physical stability and developing performance of flaw detection agent under different storage conditions sample Storage environment Physical state Test 1 (ΔC) Test 2 (ΔC) Test 3 (ΔC) Average value (ΔC) Example 1 -10℃ good 0.91 0.89 0.92 0.91 Example 1 25℃ good 0.88 0.90 0.89 0.89 Example 3 -10℃ good 0.86 0.85 0.88 0.86 Example 3 25℃ good 0.83 0.82 0.85 0.83 Comparative Example 3 -10℃ precipitation 0.65 0.66 0.64 0.65 Comparative Example 3 25℃ Layering 0.62 0.60 0.61 0.61 Comparative Example 4 -10℃ crystallization 0.58 0.57 0.59 0.58 Comparative Example 4 25℃ Layering 0.55 0.54 0.56 0.55 Experimental summary: Experimental data show that the flaw detection agents of Examples 1 and 3 maintain good physical conditions under low-temperature and room-temperature storage conditions, without stratification, precipitation or crystallization. Its excellent stability is mainly attributed to the reasonable ratio of the base liquid and the dispersant, especially the low-temperature fluidity and solubility of PEG-400 and propylene glycol, which ensure the stable dispersion performance of the flaw detection agent in extreme storage environments. In addition, the particle size of the developer powder is uniform after ultrasonic dispersion treatment, which further improves the anti-agglomeration ability during storage, so that the development effect of the flaw detection agent remains close to the fresh state after storage.

[0134] In contrast, Comparative Examples 3 and 4 had significant physical stability problems after storage. Comparative Example 3 had significant precipitation in a low temperature environment, which was presumably related to the uneven distribution of particles in the developer formulation. Due to the lack of sufficient ultrasonic dispersion, large particles gradually aggregated and settled at low temperatures, resulting in a decrease in developing performance. In a room temperature environment, liquid phase stratification occurred in Comparative Example 3, indicating that its formulation system lacked stability, which may be related to the insufficient proportion of the penetration aid, and could not maintain long-term uniform dispersion of the flaw detection agent.

[0135] The problem of comparative example 4 is more obvious. After low-temperature storage, a large number of crystals appeared in the base liquid. It is obvious that the low-temperature fluidity of PEG-200 is insufficient, which causes the base liquid components of the flaw detection agent to precipitate crystals at low temperatures. In room temperature storage, the choice of developing solvent in the formula is also defective, the developer powder has poor dispersibility, stratification occurs after long-term storage, and the developing effect is significantly weakened. Such stability problems directly affect the actual performance of the flaw detection agent in extreme environments.

[0136] These results further prove that the flaw detection agent of the present invention has successfully overcome the stratification, precipitation and crystallization problems of traditional flaw detection agents during storage by optimizing the low-temperature solubilizer, penetration aid and developer formula design. At the same time, through the ultrasonic dispersion treatment in the process, the developer powder maintains a uniform distribution during storage, significantly improving the storage stability and development performance, and providing a reliable technical guarantee for long-term application.

[0137] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An environmentally friendly colored penetrant flaw detection agent used in low temperature environments, characterized in that: By weight percentage, it includes the following components: Penetrant base liquid, accounting for 60-75%, including 45-55% low-temperature environmentally friendly solvent and 10-15% low-temperature solubilizer; Colorants, 7-12%, including fluorescent dyes 4-6% and azo dyes 3-5%; Penetration enhancers, accounting for 5-10%; Dispersants, 3-6%; Developer, accounting for 15-30%, including 10-20% of nano developer powder and 5-10% of developer solvent; Functional additives, accounting for 0.5-2%.

2. The environmentally friendly colored penetrant flaw detection agent for use in a low temperature environment according to claim 1, characterized in that: The low-temperature environmentally friendly solvent is isopropyl alcohol ester or propylene glycol fatty acid ester, and the low-temperature solubilizing agent is polyethylene glycol, 1,2-butylene glycol or glycerol.

3. The environmentally friendly colored penetrant flaw detection agent for use in a low temperature environment according to claim 1, characterized in that: The fluorescent dye is rhodamine B or 4-methylumbelliferone, and the azo dye is azobenzene or curcumin.

4. The environmentally friendly colored penetrant flaw detection agent for use in a low temperature environment according to claim 1, characterized in that: The penetration aid is alkyl glycoside, disodium sulfosuccinate or alkyl polyether sulfonate.

5. The environmentally friendly colored penetrant flaw detection agent for use in a low temperature environment according to claim 1, characterized in that: The dispersant is polysorbate-80 or ethoxylated fatty alcohol.

6. The environmentally friendly colored penetrant flaw detection agent for use in a low temperature environment according to claim 1, characterized in that: The nano developer powder is titanium dioxide or silicon dioxide with a particle size of 10-30 nm, and the developer solvent is a mixture of deionized water and ethanol in a mixing ratio of 2:

1.

7. A method for preparing an environmentally friendly colored penetrant flaw detection agent for use in a low temperature environment, characterized in that: The method for preparing an environmentally friendly colored penetrant flaw detection agent for use in a low temperature environment as claimed in any one of claims 1 to 6 comprises the following steps: S1. Mixing a low-temperature environmentally friendly solvent and a low-temperature solubilizer, and stirring to form a penetrant base liquid; S2, dissolving the fluorescent dye and the azo dye in the penetrant base liquid to form a colorant solution; S3, mixing the colorant solution, the penetration aid and the dispersant, and stirring evenly; S4, dispersing nano developer powder in a developer solvent to form a developer; S5, mixing the mixture of step S3 with a developer, performing vacuum degassing treatment, and standing to stabilize after the degassing is completed; S6. Packing to obtain the finished flaw detection agent.

8. The method for preparing an environmentally friendly colored penetrant flaw detection agent for use in a low temperature environment according to claim 7, characterized in that: In the step S1, the stirring temperature of the penetrant base liquid is 30-40° C., the stirring speed is 300-500 rpm, and the stirring time is 15-20 min.

9. The method for preparing an environmentally friendly colored penetrant flaw detection agent for use in a low temperature environment according to claim 7, characterized in that: The vacuum degree of vacuum degassing in step S5 is -0.08 to -0.1 MPa, the degassing temperature is 30-40°C, and the degassing time is 20-30 min. The specific conditions of the stabilization treatment in step S5 are: The degassed mixture was placed at 5-10°C. The stabilization time is 12-24h.

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