New loading permeation ultrasonic nondestructive testing method and system

Abstract

The invention discloses a novel loading permeation ultrasonic nondestructive testing method and system, which are used for solving the problems that initial fatigue cracks are extremely small and are in a closed state in a static state, the cracks are possibly blocked by oxides and corrosives in the fatigue cracks, and the initial fatigue cracks cannot be detected by a permeation method. Putting the test piece into the penetrating fluid, applying a load to the test piece, opening the static closed crack, releasing ultrasonic waves by an ultrasonic source, oscillating the test piece by the ultrasonic waves, expanding the opening state of the crack of the test piece, increasing the extension distance of the penetrating agent along the test piece, and cleaning oxides and corrosives in the fatigue crack of the test piece by the penetrating agent; and oil and water in the defects are replaced, so that the penetrant increases the climbing speed of a capillary tube and smoothly permeates into cracks, and the penetration capacity is improved by ultrasonic waves, so that the penetration detection sensitivity is improved, and the detection capacity of penetration on the defects of a test piece is greatly improved on the basis of loading penetration and ultrasonic detection principles.

Description

Technical Field

[0001] The present invention belongs to the field of detection technology, relates to a new non-destructive detection method, and in particular to a new load-added penetration ultrasonic non-destructive detection method and device. Background Art

[0002] Penetrant nondestructive testing can only detect open defects on the surface of materials or components, near-surface defects, and internal defects, but cannot detect internal defects in test specimens. Incipient fatigue cracks are extremely small and remain closed at rest. Furthermore, fatigue cracks contain oxides and corrosion products that may block the cracks, preventing the penetrant from penetrating the cracks. Consequently, penetrant nondestructive testing cannot detect incipient fatigue cracks. When a specimen contains both incipient fatigue cracks and internal defects, existing technologies cannot simultaneously detect both.

[0003] Therefore, it is urgent to develop a new penetration detection method to overcome the problems existing in the existing technology. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0005] A new method for nondestructive testing by ultrasonic penetration under load, characterized in that the method comprises the following steps:

[0006] S1 Pretreatment: The first step is to remove rust and oxide scale from the specimen. The second step is to place the specimen in an ultrasonic cleaning tank and use ultrasonic cleaning to clean the oil and dirt on the surface of the specimen. The third step is to place the specimen in an electric drying oven to dry the moisture on the surface of the specimen.

[0007] S2 Load Penetration: The first step is to place the specimen in the penetrating liquid and tighten the test piece with a tool; the second step is to apply a load to the specimen to make the fatigue crack open from a closed state, allowing the penetrating liquid to penetrate the crack smoothly;

[0008] S3 generates ultrasonic waves: The ultrasonic waves generated by the signal generator are directed to the specimen through the power amplifier. The ultrasonic waves cause the specimen to vibrate, further expanding the crack opening state, and increasing the distance the penetrating liquid extends along the specimen. The penetrating liquid is used to clean the oxides and corrosion products in the fatigue cracks of the specimen, allowing the penetrating liquid to penetrate the cracks smoothly.

[0009] S4 collects and analyzes ultrasonic echoes: First, scan each position of the test piece to collect real-time echo signals, and transmit the collected echo signals to the computer through the A / D converter; Second, analyze the echo signals in the computer to determine the defect position of the test piece and mark it;

[0010] S5 Cleaning and Drying: First, remove the specimen from the penetrant and place it in a water tank for cleaning. Clean the excess penetrant on the specimen surface and blow dry the excess water on the specimen surface. Second, dry it.

[0011] S6 spray imaging powder and observe and analyze: The first step is to spray imaging powder on the dried specimen to absorb the penetrant in the cracks of the specimen to form an image; the second step is to analyze the imaging traces and mark the position and size of the cracks in the specimen.

[0012] The beneficial effect of the present invention is that the new method of load-added penetration ultrasonic non-destructive testing can realize the detection of extremely small fatigue cracks in the early stage, and ultrasound improves the penetration ability, thereby improving the detection sensitivity of penetration to defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0014] Figure 1 This is a schematic diagram of a novel method and system for nondestructive testing using loaded penetrant ultrasonic technology. In the diagram: 1, crack; 2, test piece; 3, load; 4, penetrant; 5, ultrasonic wave.

[0015] Figure 2 Schematic diagram of the process of Example 3. DETAILED DESCRIPTION

[0016] The present invention will be further described below with reference to the accompanying drawings and examples.

[0017] Example 1:

[0018] A new method for nondestructive testing using loaded penetrant ultrasonic technology is proposed. The method is characterized by the following features: For extremely small initial fatigue cracks that are closed at rest, and the presence of oxides and corrosion products within the fatigue cracks that may block the cracks, penetrant testing is unable to detect them. Loaded penetrant testing and ultrasonic testing are used in conjunction with each other. The principle is that initial fatigue cracks are closed at rest. During penetrant testing, the specimen is placed in a penetrant and a load is applied to the specimen, causing the static closed state to become open. Simultaneously, an ultrasonic source releases ultrasonic waves, which cause the specimen to vibrate, further expanding the crack opening and causing the penetrant to extend farther along the specimen. The penetrant cleans oxides and corrosion products within the fatigue cracks and replaces oil and water within the defects, allowing the penetrant to penetrate smoothly into the cracks. The loaded penetrant testing method is primarily used to analyze surface defects in the specimen. Simultaneously, ultrasonic waves penetrate the specimen. Defects within the specimen cause the ultrasonic waves to reflect, and the echo signals of the ultrasonic waves are picked up. These echo signals are primarily used to analyze internal defects in the specimen. The loaded penetrant ultrasonic testing method improves penetrant testing capability and sensitivity.

[0019] The method comprises the following steps:

[0020] S1 Pretreatment: The first step is to mechanically and physically remove rust, scale and other excess materials from the specimens to prevent them from blocking the penetration of the penetrant into the cracks. The second step is to place the specimens in an ultrasonic cleaning tank to clean the oil and dirt on the surface of the specimens with ultrasonic waves. The third step is to place the specimens in an electric drying oven to dry out excess moisture on the surface of the specimens.

[0021] S2 Load Penetration: In the first step, the specimen is placed in the penetrating liquid and fastened with a loading fixture. The fatigue crack on the specimen is in a closed state. In the second step, a load is applied to the specimen. The main purpose is to make the fatigue crack open from a closed state, so that the penetrating liquid can penetrate into the crack smoothly.

[0022] S3 generates ultrasonic waves: The ultrasonic waves generated by the signal generator are directed to the specimen through the power amplifier. The ultrasonic waves cause the specimen to vibrate, further expanding the crack opening state and causing the penetrating liquid to extend along the specimen. The penetrating liquid is mainly used to clean the oxides and corrosion products in the fatigue cracks of the specimen, so that the penetrating liquid can penetrate into the crack smoothly.

[0023] S4 collects and analyzes ultrasonic echoes: In the first step, the acquisition probe comprehensively scans all positions of the test piece to collect real-time echo signals, which are then transmitted to a computer via an A / D converter. In the second step, the echo signals in the computer are analyzed. When there are defects inside the test piece, the ultrasonic echo signals undergo abnormal changes, and the defect locations of the test piece are marked, primarily to detect defects inside the test piece.

[0024] S5 Cleaning and Drying: First, remove the specimen from the penetrant and place it in a warm water bath for cleaning, mainly to clean the excess penetrant on the specimen surface, and then use an air gun to blow away the excess moisture on the specimen surface; second, dry it at a temperature of (60-90)°C and for (10-20) minutes.

[0025] S6 sprays imaging powder and observes and analyzes: The first step is to spray imaging powder on the dried specimen. The main purpose of the imaging powder is to absorb the penetrant in the cracks of the specimen to form an image; the second step is to carefully observe and analyze the imaging traces, and mark the position and size of the cracks on the specimen, mainly to realize the surface defect detection of the specimen.

[0026] Preferably, the S4 and S6 defect interpretation results are combined to comprehensively evaluate the defects of the test piece; locate the defects; quantify the defects; and characterize the defects.

[0027] Preferably, an ultrasonic source, a power amplifier, an ultrasonic signal transmitting and collecting probe, a device for adding load to the specimen, a tooling, etc. are provided, the main function of which is to tighten the specimen and smoothly generate ultrasonic waves and collect ultrasonic echoes, thereby analyzing the internal defects of the specimen.

[0028] Preferably, the penetrant is a conventional industrial penetrant with good penetrability, and the penetrant must be kept in the test piece for a sufficient penetration time.

[0029] Preferably, in the step S6, the developer is sprayed and observed, and when there is doubt about the crack defect, the black light in the darkroom is turned on for all-round observation of the test piece, and if there is a very thin yellow-green stripe on the test piece, the yellow-green stripe is wiped with a cloth soaked with acetone, and then the developer is sprayed again, and if the yellow-green stripe disappears, it indicates that the defect is a false defect; if the yellow-green stripe does not disappear, it indicates that the defect is a crack defect.

[0030] Example 2: Same as example 1

[0031] Figure 1 As shown in the embodiment, a new type of loading penetration ultrasonic nondestructive testing system is used for the initial fatigue crack (1) which is very small and in a closed state in a static state, and there is oxide and corrosion in the fatigue crack which may block the crack, so that the initial fatigue crack cannot be detected by penetration. The loading penetration and ultrasonic wave mutual auxiliary method is used, and the principle is that the initial fatigue crack is in a closed state in a static state, the test piece (2) is penetrated, the test piece is placed in the penetrant (4), a load (3) is applied to the test piece to change the static closed state into an open state, and at the same time, an ultrasonic wave source releases ultrasonic waves (5), the ultrasonic waves make the test piece vibrate, further expand the crack opening state of the test piece, increase the extension distance of the penetrant along the test piece, and the penetrant (4) cleans the oxide and corrosion in the fatigue crack of the test piece and replaces the oil and water in the defect, so that the penetrant successfully penetrates into the crack. The loading penetration method is mainly used for analyzing the surface defects of the test piece, and at the same time, the ultrasonic wave (5) penetrates the test piece, and when there is a defect in the test piece (2), the ultrasonic wave will be reflected, and the reflected wave signal is mainly used for analyzing the internal defects of the test piece. The loading penetration ultrasonic method improves the penetration detection capability and sensitivity.

[0032] The method comprises the following steps:

[0033] S1 Pretreatment: First, remove the rust, oxide scale and other excess substances on the test piece by mechanical and physical methods, mainly to prevent the excess substances from blocking the penetration of the penetrant into the crack; second, place the test piece in an ultrasonic cleaning tank to clean the oil and dirt on the surface of the test piece by ultrasonic waves; third, place the test piece in an electric heating drying box to dry the excess moisture on the surface of the test piece;

[0034] S2 Loading penetration: First, place the test piece in the penetrant, and fasten the test piece by using a loading tool, and the fatigue crack on the test piece is in a closed state; second, apply a load to the test piece, mainly to change the fatigue crack from a closed state to an open state, and promote the penetrant to successfully penetrate into the crack;

[0035] S3 generates ultrasonic waves: The ultrasonic waves generated by the signal generator are directed to the specimen through the power amplifier. The ultrasonic waves cause the specimen to vibrate, further expanding the crack opening state and causing the penetrating liquid to extend along the specimen. The penetrating liquid is mainly used to clean the oxides and corrosion products in the fatigue cracks of the specimen, so that the penetrating liquid can penetrate into the crack smoothly.

[0036] S4 collects and analyzes ultrasonic echoes: In the first step, the acquisition probe comprehensively scans all positions of the test piece to collect real-time echo signals, which are then transmitted to a computer via an A / D converter. In the second step, the echo signals in the computer are analyzed. When there are defects inside the test piece, the ultrasonic echo signals undergo abnormal changes, and the defect locations of the test piece are marked, primarily to detect defects inside the test piece.

[0037] S5 Cleaning and Drying: First, remove the specimen from the penetrant and place it in a warm water bath for cleaning, mainly to clean the excess penetrant on the specimen surface, and then use an air gun to blow away the excess moisture on the specimen surface; second, dry it at a temperature of (60-90)°C and for (10-20) minutes.

[0038] S6 sprays imaging powder and observes and analyzes: The first step is to spray imaging powder on the dried specimen. The main purpose of the imaging powder is to absorb the penetrant in the cracks of the specimen to form an image; the second step is to carefully observe and analyze the imaging traces, and mark the position and size of the cracks on the specimen, mainly to realize the surface defect detection of the specimen.

[0039] Preferably, the S4 and S6 defect interpretation results are combined to comprehensively evaluate the defects of the test piece; locate the defects; quantify the defects; and characterize the defects.

[0040] Preferably, an ultrasonic source, a power amplifier, an ultrasonic signal transmitting and collecting probe, a device for adding load to the specimen, a tooling, etc. are provided, the main function of which is to tighten the specimen and smoothly generate ultrasonic waves and collect ultrasonic echoes, thereby analyzing the internal defects of the specimen.

[0041] Preferably, the penetrant is a conventional industrial penetrant with good permeability, and a sufficient penetration time must be maintained when penetrating the specimen.

[0042] Preferably, in step S6, the developer powder is sprayed and observed and analyzed. When there is doubt about the crack defect, the specimen is observed in all directions under a black light in a dark room. If there are very fine yellow-green stripes on the specimen, wipe it with a cloth soaked in acetone, and then gently and evenly spray the developer powder. If the yellow-green stripes disappear, it indicates a pseudo defect; if the yellow-green stripes do not disappear, it indicates a crack defect.

[0043] Example 3:

[0044] A novel method for nondestructive testing by ultrasonic penetration under load, characterized by comprising the following steps:

[0045] S1 pretreatment: mechanical and physical methods to remove rust, oxide scale and other redundant materials on the specimen;

[0046] S2 Ultrasonic cleaning: Place the specimen in an ultrasonic cleaning tank and use ultrasonic waves to clean the oil and dirt on the surface of the specimen;

[0047] S3 Multifunctional cleaning: Place the specimen into the multifunctional cleaning tank and clean it with pressurized water;

[0048] S4 Electric heating drying: Place the specimen into an electric heating drying oven for drying;

[0049] S5 Self-emulsification fluorescent penetrant: Place the specimen into the fluorescent liquid in the self-emulsification penetrant tank;

[0050] S6 Loading: Apply load to the specimen to make the fatigue crack change from static state to open state;

[0051] S7 generates ultrasonic waves: the ultrasonic source generates ultrasonic waves, which penetrate the test piece;

[0052] S8 collects ultrasonic echoes: Ultrasonic echoes are used to analyze internal defects of the specimen;

[0053] S9 Multifunctional Cleaning: Place the specimen into the multifunctional cleaning tank and clean it with water pressure;

[0054] S10 Immersion cleaning: Place the specimen into the immersion tank for cleaning;

[0055] S11 Air gun drying: Use a water gun to dry the surface moisture of the specimen;

[0056] S12 Electric heating drying: Place the specimen in an electric heating drying oven for drying;

[0057] S13 imaging powder spraying: put the test piece into the imaging tank for powder spraying;

[0058] S14 Observation and Analysis: Under darkroom conditions, use a black light to evaluate the surface defects of the specimen;

[0059] S15 Defect marking: Mark the location of the defect with a red marker;

[0060] S16 comprehensive evaluation: Combine the evaluation results of S8 and S15 to comprehensively evaluate the defects of the specimen;

[0061] S17 Ultrasonic cleaning: Place the qualified test piece into the ultrasonic cleaning tank and clean it with ultrasonic waves;

[0062] S18 Multifunctional cleaning: Place the qualified test piece into the multifunctional cleaning tank and clean the test piece with pressurized water;

[0063] S19 Electric drying: Place qualified test pieces in an electric drying oven for drying.

[0064] Preferably, the S1 pretreatment comprises the following steps:

[0065] S101 removing stains and attachments on the surface of the test piece by mechanical physical means;

[0066] S102 placing the test piece in the penetrating liquid, and the test piece is completely submerged in the penetrating liquid.

[0067] Preferably, the S6 loading comprises the following steps:

[0068] S601 clamping and fixing the test piece by the loading fixture, and the crack on the test piece is in a normal closed state;

[0069] S602 loading the test piece in two directions, or in a single direction, or in one up and one down direction;

[0070] S603 after loading the test piece, the fatigue crack of the test piece changes from a closed state to an open state, which facilitates the penetration of the penetrating liquid.

[0071] Preferably, the S7 ultrasonic wave generation comprises the following steps:

[0072] S701 the signal generator generates ultrasonic waves, and the ultrasonic waves are emitted to the test piece through a power amplifier;

[0073] S701 the ultrasonic waves make the test piece vibrate, expand the open state of the crack of the test piece, promote the increase of the extension distance of the penetrating agent along the test piece, clean the oxides and corrosion in the fatigue crack of the test piece, replace the oil and water in the defect, and make the penetrating agent improve the capillary climbing speed to smoothly penetrate into the crack;

[0074] S701 the ultrasonic waves penetrate the test piece, and when there is a defect in the test piece, the ultrasonic waves will be reflected.

[0075] Preferably, the S8 ultrasonic echo collection comprises the following steps:

[0076] S801 collecting the real-time echo signals collected by the probe at each position of the test piece;

[0077] S802 the probe transmits the collected echo signals to the computer through an A / D converter;

[0078] S803 analyzing the echo signals in the computer, and if there is a defect in the test piece, an alarm is generated, and the defect position of the test piece is marked;

[0079] S804 using a standard sample to correct the detection system, and the correction steps are S801-S803 in S8;

[0080] After S805 calibration is completed, the test piece is tested again. If the defect in the test piece is smaller than the defect in the standard sample, the system will not alarm; if the defect in the test piece is larger than the defect in the standard sample, the system will alarm, and the defect will be manually interpreted and located, qualitatively and quantitatively determined.

[0081] Preferably, the S9 multifunctional cleaning is to place the test piece into a multifunctional cleaning tank and clean the test piece with a pressurized water gun. The cleaning water pressure is ≤0.27MPa and the cleaning time is 2min-5min.

[0082] Preferably, in the step S10, the specimen is placed in a warm water tank to clean the penetrant, and the cleaning is performed with warm water in the range of 10-30°C. The warm water tank is equipped with ultrasonic wave to assist in the cleaning, and the cleaning time range is 10-20 minutes. If the penetrant on the specimen is not completely cleaned, a water gun is used to further clean the part.

[0083] Preferably, the S11 air gun is used for drying, and excess moisture of the specimen is removed using an air gun with compressed air, the compressed air pressure is ≤0.17 MPa, and the distance between the air gun nozzle and the specimen is ≥30 cm.

[0084] Preferably, the S12 electric drying is carried out in a drying oven using fully enclosed hot circulating air, with a drying temperature range of 50-80°C and a drying time of 5-15 minutes;

[0085] Preferably, the S13 imaging and powder spraying comprises the following steps:

[0086] S1301 Place the dried specimen in a closed developing tank;

[0087] The S1302 developing tank is equipped with an air blowing port on the outside. The developing powder in the tank is lifted up by an air gun. The blowing frequency is 2-3 times, and each blowing time is 1-2 seconds.

[0088] S1303 Wait for 15-30 minutes until the developing powder falls and completely covers the surface of the specimen. The developing powder absorbs the penetrant in the cracks of the specimen to form an image.

[0089] Preferably, the S14 observation and analysis includes the following steps:

[0090] S1401 inspectors wear protective gear in the darkroom and their vision needs to adapt for 5 minutes;

[0091] S1402 Use an ultraviolet intensity meter to measure the ultraviolet intensity. The ultraviolet intensity at a distance of 380 mm from the light source should be no less than 1000 μW / cm 2 ;

[0092] S1403 Turn off the fluorescent light and turn on the black light to observe the test piece in all directions in a dark room. If there are very fine yellow-green stripes on the test piece, wipe it with a cloth soaked in acetone, and then gently and evenly spray the developer powder. If the yellow-green stripes disappear, it indicates a micro defect; if the yellow-green stripes do not disappear, it indicates a defect.

[0093] Preferably, the S15 defect marking is to mark the location, size and nature of the defect with a marker;

[0094] Preferably, the S16 comprehensive evaluation combines the evaluation results of S8 and S15 to comprehensively evaluate the defects of the test piece; locate the defects; quantify the defects; and characterize the defects.

[0095] Preferably, the S17 ultrasonic cleaning is to place the qualified test piece in an ultrasonic cleaning tank for cleaning, the cleaning water temperature is 30°-45°, and the cleaning time is 5min-10min.

[0096] Preferably, the S18 multi-function cleaning time is 5min-15min:

[0097] Preferably, the temperature of the S19 electric drying is 60°-70°, and the time of the S19 electric drying is 10min-20min.

[0098] Preferably, the test piece has already produced early fatigue cracks, and the surface is accompanied by oxides and corrosion products.

[0099] Preferably, the penetrant is a conventional industrial penetrant with good permeability, and a sufficient penetration time must be maintained when penetrating the specimen.

[0100] Preferably, an ultrasonic source, an ultrasonic signal transmitting and collecting probe, a device for applying a load to the specimen, a tooling, etc. are provided;

[0101] Preferably, the load is applied to change the fatigue crack from a closed state to an open state, and the ultrasonic wave and the load together cause the penetrant to penetrate into the crack of the specimen. The ultrasonic wave realizes the internal defect detection of the specimen, and the penetration realizes the surface defect detection. It can take into account the detection of internal and surface defects, and realize the simultaneous detection of surface defects and internal defects, thereby improving the defect detection capability.

[0102] The above description is only a detailed description of the present invention, but the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by ordinary technicians in this field, any modifications, equivalences, replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A new method for nondestructive testing by ultrasonic penetration under load, characterized by: The method comprises the following steps: S1 Pretreatment: The first step is to remove rust and oxide scale from the specimen. The second step is to place the specimen in an ultrasonic cleaning tank and use ultrasonic cleaning to clean the oil and dirt on the surface of the specimen. The third step is to place the specimen in an electric drying oven to dry the moisture on the surface of the specimen. S2 Load Penetration: The first step is to place the specimen in the penetrating liquid and tighten the test piece with a tool; the second step is to apply a load to the specimen to make the fatigue crack open from a closed state, allowing the penetrating liquid to penetrate the crack smoothly; S3 generates ultrasonic waves: The ultrasonic waves generated by the signal generator are directed to the specimen through the power amplifier. The ultrasonic waves cause the specimen to vibrate, further expanding the crack opening state, and increasing the distance the penetrating liquid extends along the specimen. The penetrating liquid is used to clean the oxides and corrosion products in the fatigue cracks of the specimen, allowing the penetrating liquid to penetrate the cracks smoothly. S4 collects and analyzes ultrasonic echoes: First, scan each position of the test piece to collect real-time echo signals, and transmit the collected echo signals to the computer through the A / D converter; Second, analyze the echo signals in the computer to determine the defect position of the test piece and mark it; S5 Cleaning and Drying: First, remove the specimen from the penetrant and place it in a water tank for cleaning. Clean the excess penetrant on the specimen surface and blow dry the excess water on the specimen surface. Second, dry it. S6 spray imaging powder and observe and analyze: The first step is to spray imaging powder on the dried specimen to absorb the penetrant in the cracks of the specimen to form an image; the second step is to analyze the imaging traces and mark the position and size of the cracks in the specimen.

2. The novel method of nondestructive testing by ultrasonic penetration under load according to claim 1, characterized in that: Combined with the S4 and S6 defect interpretation results, the specimen defects are comprehensively evaluated.

3. The novel method of nondestructive testing by ultrasonic penetration under load according to claim 1, characterized in that: The system used includes a signal generator, a power amplifier, an ultrasonic signal transmitting and collecting probe, and a tooling for applying load to the specimen. The tooling is used to tighten the specimen and increase the load. The signal generator and power amplifier are used to generate and amplify ultrasonic waves. The ultrasonic signal transmitter is used to transmit ultrasonic waves, and the collecting probe is used to collect ultrasonic echoes.

4. The novel method of nondestructive testing by ultrasonic penetration under load according to claim 1, characterized in that: The permeate is a conventional industrial permeate.

5. The novel method of nondestructive testing by ultrasonic penetration under load according to claim 1 is characterized in that: In step S6, the developer powder is sprayed and observed and analyzed. Specifically, the test piece is observed in a dark room under a black light. The yellow-green stripes on the test piece are wiped with a cloth soaked in acetone, and then the developer powder is evenly sprayed again. If the yellow-green stripes disappear, it indicates a pseudo defect; if the yellow-green stripes do not disappear, it indicates a crack defect.

6. The novel method of nondestructive testing by ultrasonic penetration under load according to claim 1 is characterized in that: The second step of S5 is drying, with a drying temperature of (60-90)°C and a drying time of (10-20) min.

7. The novel method of nondestructive testing by ultrasonic penetration under load according to claim 1, characterized in that: Clean the excess penetrant on the surface of the test piece: Place the test piece in a multi-functional cleaning tank and clean the test piece with a pressurized water gun. The cleaning water pressure is ≤0.27MPa and the cleaning time is 2min-5min.

8. The novel method of nondestructive testing by ultrasonic penetration under load according to claim 1, characterized in that: Step S5 also includes immersion cleaning, placing the specimen in a warm water tank to clean the penetrant. The cleaning uses warm water in the range of 10-30°C. The warm water tank is equipped with ultrasonic waves to assist in the cleaning. The cleaning time range is 10-20 minutes. If the specimen layout is not cleaned by the penetrant, a water gun is used to further clean the area.

9. The novel method of nondestructive testing by ultrasonic penetration under load according to claim 1, characterized in that: The load on the specimen is set to be applied in two directions, up and down, or in a single direction, or in both directions.

10. The novel method of nondestructive testing by ultrasonic penetration under load according to claim 1, characterized in that: In S4, a standard specimen is used for testing and the defects in the specimen are judged to be smaller than or less than the defects of the standard specimen for marking.

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