Ultrasonic flaw detection device and detection method thereof

Abstract

The invention relates to the technical field of ultrasonic flaw detection, and particularly discloses an ultrasonic flaw detection device and a detection method thereof. Measuring the depth of the wound according to the velocity of the ultrasonic; measuring the size of a wound in the standard component; determining the optimal frequency range of standard part flaw detection; measuring the propagation speed of ultrasonic waves in the brass block and the aluminum block; measuring an ultrasonic attenuation coefficient in the standard component; and measuring the ultrasonic attenuation coefficients in the brass block and the aluminum block, wherein uncertainty analysis needs to be carried out on all the steps, and Matlab is used for drawing an error bar. According to the invention, the basic function of flaw detection is realized, the accurate positioning of the wound in the test block and the measurement of the size of the wound are completed, the sound velocity and attenuation coefficient of sound waves propagating in different metals are researched, and the application in various materials is realized.

Description

Technical Field

[0001] The invention relates to the technical field of ultrasonic flaw detection, in particular to an ultrasonic flaw detection device and a detection method thereof. Background Art

[0002] Nondestructive testing is a technical means to evaluate the quality of the object being tested by detecting the changes in the physical properties of light, electricity, sound, magnetism, etc. caused by the defects to determine the size, location, nature and other information of the internal or surface defects without damaging or affecting the performance of the object being tested. It usually includes six major common methods: X-ray testing, penetration testing, magnetic particle testing, ultrasonic testing, eddy current testing and infrared testing. Nowadays, ultrasonic testing technology has been widely used in all aspects of production, which can not only achieve fast but also relatively accurate preliminary testing. Ultrasonic nondestructive testing has many advantages such as easy application, strong applicability, high accuracy, and easy automation. It plays a vital role in important fields such as industry, medical care, and construction in my country.

[0003] Ultrasonic flaw detector is a non-destructive testing technology used to detect defects inside materials. Its development history can be traced back to the first time that Sakhanov of the Soviet Union proposed the use of penetration method to inspect the internal structure of solids. During World War II, the application of sonar technology promoted the birth of pulse reflection ultrasonic flaw detector, which was originally developed by the United States and the United Kingdom in the 1940s and gradually applied to the industrial field. In the 1950s, with the introduction of piezoelectric ceramic chips, ultrasonic flaw detectors began to be widely used in industries such as steel, shipbuilding and machinery manufacturing. In the 1970s, the advancement of electronic components and electronic technology significantly improved the performance of ultrasonic flaw detectors, and the introduction of quantitative methods improved the comparability and credibility of test results. In the 1980s, the emergence of digital ultrasonic flaw detectors and the development of computer technology further promoted the development of automatic ultrasonic testing technology.

[0004] In recent years, domestic digital ultrasonic flaw detectors have begun to form large-scale production and have been widely used, marking that domestic ultrasonic flaw detection technology has entered a new stage of development.

[0005] Due to the widespread use of ultrasonic flaw detection in non-destructive testing, many experts and scholars have provided valuable reference directions and suggestions for the research and application of ultrasonic flaw detection.

[0006] Song Jianping and other scholars explored the signal processing process of the ultrasonic flaw detector's transceiver circuit, analyzed the design points of the transceiver circuit according to the flaw detector's requirements for the transceiver circuit, and explained in detail the selection basis, circuit characteristics, and technical indicators of key components in each unit circuit, thus building a framework for the construction of an ultrasonic flaw detector.

[0007] Yin Chang and other scholars used the pulse transmission insertion substitution method to measure the sound velocity of chromium stainless steel, chromium-nickel stainless steel and ordinary carbon steel at a frequency of 4.5MHz, and performed Fourier transform on the measured signal to obtain the amplitude spectrum and calculate the sound attenuation coefficient. This provides ideas and methods for the measurement of sound velocity and attenuation coefficient.

[0008] Zhan Shaozheng and other scholars have conducted research on the existence of interference signals in the test results and found that too high a repetition frequency will shorten the interval between two excitation pulses, which can easily cause the pulse echo signal generated by the ultrasonic probe when it is stimulated by the previous pulse to not completely decay and disappear in time, and fall into the next trigger cycle for display, forming interference signals on the instrument display screen, such as phantom waves, false defect signals, etc., which can cause misjudgment of the test results. This provides ideas for exploring the authenticity of the test results.

[0009] Dong Zheng and other scholars analyzed the process and results of ultrasonic flaw detection, analyzed and evaluated each uncertainty component, and finally obtained the result of synthetic uncertainty evaluation. This method has certain reference value for the uncertainty evaluation of the sound path and equivalent size of metal material defects.

[0010] When ultrasonic waves propagate in a medium, their energy gradually weakens as the propagation distance increases. This phenomenon is called ultrasonic attenuation.

[0011] Theoretically, there are three main reasons for the attenuation of ultrasound: ultrasound attenuation caused by sound beam diffusion, ultrasound attenuation caused by scattering, and ultrasound attenuation caused by medium absorption. The attenuation of ultrasound in solids is mainly caused by internal friction and heat conduction.

[0012] The frequency component of the ultrasonic pulse wave emitted by the probe in ultrasonic flaw detection is determined by the shape of the excitation pulse, the type of wafer and the installation process. When using ultrasonic flaw detection, the first problem to be solved is how to emit and receive ultrasonic waves. Summary of the invention

[0013] In view of the above-mentioned problems in the prior art, the present invention provides an ultrasonic flaw detection device and a detection method thereof, which realizes the flaw detection function and simplifies the equipment. Compared with ultrasonic flaw detection instruments on the market, the cost is greatly reduced and the accuracy difference is relatively small. The signal waveform and flaw detection method can be changed according to the specific application scenario, thereby broadening the scope of use.

[0014] The technical solution adopted by the present invention is as follows:

[0015] A detection method for an ultrasonic flaw detection device, the steps of the detection method are as follows:

[0016] S1. Determine the ultrasonic propagation velocity in the standard part, calculate the sound velocity and the average time of ultrasonic propagation in the delay block, perform uncertainty analysis on the sound velocity and draw error bars using Matlab;

[0017] S2, measuring the depth of the wound based on the speed of ultrasound;

[0018] S3, measure the wound size in the standard part, make uncertainty analysis and draw error bars;

[0019] S4. Determine the optimal frequency range for standard parts flaw detection;

[0020] S5. Measure the ultrasonic propagation velocity in the brass block and the aluminum block, perform uncertainty analysis and draw error bars;

[0021] S6. Measure the ultrasonic attenuation coefficient in the standard part, perform uncertainty analysis and draw error bars;

[0022] S7. Measure the ultrasonic attenuation coefficient in the brass block and the aluminum block, perform uncertainty analysis and draw error bars.

[0023] Preferably, the calculation formula for the propagation speed of the ultrasonic wave in the standard component in step S1 is: The formula for calculating the propagation time of the ultrasonic wave in the delay block is: Δt0 = Δt1 - Δt2;

[0024] Where ν is the sound velocity of the material being tested, D is the thickness of the test block, Δt1 is the time difference between the initial ultrasonic wave and the first echo on the bottom surface of the standard part, and Δt2 is the time difference between the first and second bottom surface echoes.

[0025] Preferably, the calculation formula for the wound depth in step S2 is:

[0026]

[0027] Where l is the wound depth, and Δt3 is the time difference between the first echo of the ultrasonic wave on the upper surface of the wound of the standard part and the first echo on the bottom surface.

[0028] Preferably, step S3 includes the following steps:

[0029] Step 1: Repeat step S2 to measure the front and back depths of the wound to obtain the longitudinal diameter of the wound, which is calculated as follows:

[0030]

[0031] Where d is the wound thickness, Δt'3 is the time difference between the first bottom echo and the first wound upper surface echo after the workpiece is reversed;

[0032] Step 2: Use the half-wave method to measure the transverse diameter of the wound.

[0033] Preferably, it is characterized in that in the step S5, the time difference Δt between the initial wave and the first bottom surface echo of the ultrasonic wave in the brass block and the aluminum block is measured respectively, and the propagation speed ν of the ultrasonic wave in the brass block and the aluminum block is calculated by the formula:

[0034]

[0035] Preferably, the calculation formula of the attenuation coefficient δ of the standard part, the brass block and the aluminum block at a certain frequency is:

[0036]

[0037] Where A1 is the peak-to-peak value of the sinusoidal signal directly transmitted to the straight probe, and A2 is the peak-to-peak value of the sinusoidal signal after the ultrasonic wave passes through the standard, brass block, and aluminum block.

[0038] Preferably, the uncertainty calculation formula is: U k0 =K×U C0 ;

[0039]

[0040] Where U c0 is the standard uncertainty constant of the ultrasonic propagation velocity v in the workpiece, U k0 is the expanded uncertainty constant of v, k is the coverage factor, U D is the uncertainty constant of thickness D, U t2 is the uncertainty constant of the time difference Δt2.

[0041] Preferably, the sound velocity and wound depth are measured by a pulse multiple reflection method, and the attenuation coefficient of the test block is measured by a penetration method.

[0042] Preferably, a single dual crystal probe design device is used to measure the speed of sound and the wound depth; and a dual probe design device is used to measure the attenuation coefficient of the test block.

[0043] An ultrasonic flaw detection device comprises an equipment module and a data analysis software module. The equipment module comprises an oscilloscope, a function signal generator, a standard ultrasonic test block, a metal block, a dual crystal probe, a straight probe, a medical ultrasonic coupling agent, a vernier caliper, a scale, and a probe line; the data analysis software module comprises a Device Manager virtual oscilloscope and WaveAnalysis.

[0044] The present invention has the following characteristics and advantages:

[0045] (1) The function signal generator, oscilloscope and dual crystal probe are used as the transceiver circuit at the same time, realizing the function of flaw detection, simplifying the equipment, and completing the precise positioning of the wound in the test block and the measurement of the wound size;

[0046] (2) Compared with other ultrasonic flaw detection instruments on the market, the cost is greatly reduced and the accuracy is relatively close;

[0047] (3) The present invention summarizes and explores a variety of methods that are most compatible with the equipment and test blocks, and measures the sound velocity and attenuation coefficient in a variety of materials, including standard test blocks of steel, aluminum blocks and brass blocks, thereby broadening the application scope of ultrasonic flaw detection and allowing it to be applied to more different materials for measurement.

[0048] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 : is a diagram of instruments used in the device of the present invention, wherein (a) is a UTD7122F oscilloscope, (b) is a UTG7025B function signal generator, (c) is a 30*40*50mm aluminum block and a 30*40*50mm brass block, (d) is a 5Pφ20 straight probe and a 5Pφ10F10 dual crystal probe, (e) RB-1 standard ultrasonic test block vernier caliper and scale, (f) is a medical ultrasonic coupling agent and a 4mm wound steel block;

[0050] Figure 2 1 is a diagram of the overall experimental device of the present invention, wherein (a) is a diagram of the experimental device using a single dual crystal probe design, and (b) is a diagram of the experimental device using a dual probe design;

[0051] Figure 3 It is a schematic diagram of multiple reflections of a pulse;

[0052] Figure 4 It is a schematic diagram of sinusoidal signal attenuation;

[0053] Figure 5 It is a schematic diagram of the oscilloscope waveform;

[0054] Figure 6 is a schematic diagram of thickness measurement;

[0055] Figure 7 It is a schematic diagram of the application of the half-wave method;

[0056] Figure 8 It is a schematic diagram of the peak attenuation of a sinusoidal signal;

[0057] Fig. 9 This is the waveform of the continuous pulse signal of the RB-1 test block;

[0058] Fig.10is the standard error bar graph of the sound velocity in the RB-1 test block;

[0059] Fig.11 This is the waveform of the continuous pulse signal of the brass block;

[0060] Fig.12 is the standard error bar graph of the sound velocity in the brass block;

[0061] Fig.13 It is the waveform diagram of continuous pulse signal in aluminum block;

[0062] Fig.14 is the standard error bar graph of the speed of sound in the aluminum block;

[0063] Fig.15 It is the peak-to-peak graph of a continuous sinusoidal signal on an oscilloscope;

[0064] Fig.16 Graphs showing the waveform peak value of wounds at different depths as a function of frequency, where (a) is the waveform peak value of a 3.5 mm wound as a function of frequency, (b) is the waveform peak value of an 8.5 mm wound as a function of frequency, (c) is the waveform peak value of a 13.5 mm wound as a function of frequency, (d) is the waveform peak value of an 18.5 mm wound as a function of frequency, and (e) is the waveform peak value of a 25 mm bottom surface as a function of frequency;

[0065] Fig.17 This is the waveform of the continuous pulse signal detecting a 3.5mm wound in RB-1;

[0066] Fig.18 is the standard error bar graph of 3.5 mm wound in RB-1;

[0067] Fig.19 This is the waveform of the continuous pulse signal detecting a 13.5mm wound in RB-1;

[0068] Fig. 20 is the standard error bar graph of 13.5 mm wound in RB-1;

[0069] Fig.21 is the standard error bar graph of 3.5 mm through-hole wound thickness in RB-1;

[0070] Fig. 22 It is the standard error bar graph of the wound thickness of 13.5mm through hole in RB-1. DETAILED DESCRIPTION

[0071] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0072] like Figure 1As shown, the present invention provides an ultrasonic flaw detection device, including the following devices: an equipment module and a data analysis software module, wherein the equipment module includes an oscilloscope, a function signal generator, a standard ultrasonic test block, a metal block, a dual crystal probe, a straight probe, a medical ultrasonic coupling agent, a vernier caliper, a ruler, and a probe line; the data analysis software module includes a DeviceManager virtual oscilloscope and WaveAnalysis.

[0073] like Figure 2 As shown, the present invention uses a pulse multiple reflection method to measure the sound velocity and wound depth, and uses a single dual crystal probe to design an experimental device. Figure 3 As shown, the function signal generator, as the signal generating part of the device, repeatedly generates excitation electric pulses. The electric signal is transmitted to the probe by the dual-crystal probe line, converted into an ultrasonic signal by the piezoelectric effect, and reflected many times in the test block. The dual-crystal probe receives the reflected ultrasonic signal, generates an electric signal by the inverse piezoelectric effect, and displays it on the oscilloscope. The waveform is read by the virtual oscilloscope and analyzed.

[0074] The present invention adopts the sinusoidal signal attenuation method to determine the attenuation coefficient of the test block, and adopts a double probe design experimental device and a single double crystal probe design experimental device. Figure 4 As shown, the function signal generator sends out a continuous sinusoidal wave signal. Similarly, in the reflection method, the ultrasonic signal of the dual crystal probe is transmitted into the test block, emitted at the corresponding surface, received by the straight probe and the electrical signal is displayed on the oscilloscope. The attenuation coefficient is determined by comparing and analyzing the changes in the peak-to-peak amplitudes of the initial wave signal and the emitted wave signal.

[0075] The specific experimental steps of this embodiment are as follows:

[0076] Step 1: Calibrate the oscilloscope and use the built-in calibration signal to perform a self-test on the oscilloscope;

[0077] Step 2, ultrasonic sound velocity measurement, including measuring the ultrasonic propagation velocity in the RB-1 standard part, measuring the ultrasonic propagation velocity in the brass block and the aluminum block;

[0078] Step 3, measuring the ultrasonic attenuation coefficient, including measuring the ultrasonic attenuation coefficient in the RB-1 standard part and measuring the ultrasonic attenuation coefficient in the brass block;

[0079] Step 4: Ultrasonic flaw detection, including determining the best flaw detection frequency, measuring the depth and thickness of the wound according to the speed of the ultrasonic wave, and measuring the width of the wound using the half-wave method.

[0080] In step 2, the specific operation of determining the ultrasonic propagation velocity in the RB-1 standard is as follows:

[0081] (1) On the RB-1 standard part, mark sample points every 30 mm at 10 mm (path 1) and 30 mm (path 2) from the edge; use a vernier caliper to measure the thickness of each sample point on the standard part and take the average value;

[0082] (2) Connect the dual crystal probe, signal generator, oscilloscope and computer; adjust the signal generator to output a 4-cycle pulse train electrical signal with a carrier parameter of 5 MHz and a 5 Vpp sine wave;

[0083] (3) Apply coupling agent evenly on the sample point, place the probe on the sample point, adjust the probe direction so that the center line of the dual crystal probe coincides with path 1 or 2, and apply a large constant pressure on the probe;

[0084] (4) Adjust the oscilloscope to observe and record a clear and stable waveform. Repeat the recording 10 times for each sample point.

[0085] (5) Use WaveAnalysis waveform analysis software to read the time difference Δt1 between the initial wave and the first bottom surface reflection wave, and the time difference Δt2 between the first bottom surface reflection wave and the second bottom surface reflection wave. Then, the ultrasonic wave propagation time Δt0 in the delay block is Δt1-Δt2.

[0086] (6) Calculate the speed of sound and the average time it takes for ultrasonic waves to propagate in the delay block, perform uncertainty analysis on the speed of sound, and plot error bars using Matlab.

[0087] The ultrasonic velocity in the RB-1 test block was measured by the pulse reflection method. The waveform is shown in the figure below. Fig. 9 The waveform is analyzed using WaveAnalysis waveform analysis software to obtain the time interval between the primary and secondary bottom wall echoes, and the data is recorded to obtain the sound velocity.

[0088] Table 1 Measurement of sound velocity in RB-1 (path A)

[0089] Position(mm) Average propagation time (μs) Average sound speed (m / s) 30 8.60 5814.79 60 8.57 5836.07 90 8.58 5828.91 120 8.56 5843.85 150 8.58 5831.19 180 8.61 5809.35 210 8.66 5777.29 240 8.59 5820.17 270 8.56 5842.49

[0090] Table 2 Measurement of sound velocity in RB-1 (path B)

[0091] Position(mm) Average propagation time (μs) Average sound speed (m / s) 30 8.562 5839.76 60 8.618 5801.94 90 8.625 5797.41 120 8.578 5829.08 150 8.605 5810.73 180 8.568 5835.96 210 8.568 5835.80 240 8.633 5792.02 270 8.572 5833.30

[0092] The above data are analyzed for error, and the standard error formula is used to analyze each sampling point. The error bar image is as follows: Fig.10 Shown:

[0093]

[0094] The experimentally measured average sound velocity in the standard part is 5821m / s. Fig.10It can be seen that the data error is small and the accuracy is high. The experimental value is basically consistent with the steel sound velocity of 5977m / s obtained by Yin Chang and other scholars. The experimental results are good. It can be seen that this experimental device has high measurement accuracy and high accuracy and can be widely used

[0095] After completing the precision analysis, uncertainty analysis is performed on the experimental data.

[0096] In this experiment, the sound velocity of the standard block is obtained by 2D = νΔt2. Applying the above uncertainty calculation formula, we can get:

[0097]

[0098] U t2 =0.006(μs)

[0099]

[0100] Taking the confidence probability as 95% and the coverage factor k = 2, the expanded uncertainty is U = k × μ.

[0101] U k0 =K×U C0 =10(m / s);

[0102] The error analysis and uncertainty analysis steps in the following experiments are consistent with the process in this experiment, so only the calculation formula and results are given without further elaboration.

[0103] After verifying the accuracy of sound velocity measurement in RB-1 standard steel, the experimental setup was applied to different materials.

[0104] In step 2, the specific operation of measuring the ultrasonic wave propagation velocity in the brass block and the aluminum block is as follows:

[0105] (1) Use a vernier caliper to measure the thickness of the brass block and the aluminum block, repeat ten times; mark sample points on their surfaces at intervals of 5 mm;

[0106] (2) Repeat steps (2), (3), (4) of Experiment 1;

[0107] (3) Use WaveAnalysis waveform analysis software to read the time difference Δt between the initial wave and the first bottom surface reflection wave, then the transmission time of the ultrasonic wave in the test block Δt4 = Δt1-Δt0;

[0108] (4) Calculate the wave velocity, perform uncertainty analysis and draw error bars.

[0109] The obtained continuous pulse signal waveform of the brass block is as follows: Fig.11 As shown, the waveform is analyzed using WaveAnalysis waveform analysis software to obtain the time interval between the initial wave and the first ground reflection wave, and the data is recorded to obtain the sound speed.

[0110] Table 3 Determination of sound velocity in brass block

[0111]

[0112] The standard error bar graph of the sound velocity in the brass block is shown in Fig.12 As shown in the figure, the average propagation speed of ultrasonic waves in brass is calculated to be 4299 m / s. As can be seen from the error bar, the experimental data has high accuracy and is in good agreement with the result of 4430 m / s measured by Zhou Hongxian and other scholars, and the experimental results are good.

[0113] The waveform of the continuous pulse signal in the aluminum block is as follows: Fig.13 As shown, the waveform is analyzed using WaveAnalysis waveform analysis software to obtain the time interval between the initial wave and the first ground reflection wave, and the data is recorded to obtain the sound speed.

[0114] Table 4 Determination of sound velocity in aluminum blocks

[0115]

[0116] The average propagation speed of ultrasonic waves in aluminum blocks was calculated to be 6395 m / s, which is close to the result of 6451.75 m / s measured by Li Xiaozhi, and the experimental results are good.

[0117] The standard error bar graph of the sound velocity in the aluminum block is shown in Fig.14 As shown, the uncertainty of the brass velocity is calculated as: Uncertainty of the aluminum block velocity:

[0118] Where U1 is the uncertainty of the time interval between the first bottom echo and the second bottom echo of the standard part, U2 is the uncertainty of the time interval between the first bottom echo and the first initial wave of the standard part, and U3 is the uncertainty of the time interval between the first bottom echo and the first initial wave of the test block.

[0119] The expanded uncertainties are: U K1 = k × U ν1 =4(m / s);U K2 = k × U ν2 =4(m / s).

[0120] The attenuation coefficient is measured by the transmission method, which is achieved by real-time recording of the peak-to-peak value of the continuous sinusoidal signal of the oscilloscope. The peak-to-peak value of the continuous sinusoidal signal of the oscilloscope is shown in Fig.15 shown.

[0121] Table 5 Initial incoming amplitude

[0122]

[0123]

[0124] In step 3, the specific operation of measuring the ultrasonic attenuation coefficient in the RB-1 standard is as follows:

[0125] (1) Take a sample point every 10 m along the midline of the 10 cm uninjured part of the RB-1 standard (a total of 11 points);

[0126] (2) Connect the dual crystal probe, straight probe, signal generator, oscilloscope and computer, adjust the signal generator to output a continuous sine wave electrical signal of 5MHz, 5Vpp:

[0127] (3) Apply coupling agent evenly on the surfaces of the two probes, tightly fit the dual-element probe and the straight probe, and measure the amplitude A1 of the incoming electrical signal. Repeat 10 times.

[0128] (4) Apply coupling agent evenly on the sample point, fit the dual crystal probe and the straight probe tightly to the sample points on the opposite sides of the test block, adjust the probe direction so that its mark coincides with the sample point mark, measure the electrical signal amplitude A2, and repeat 10 times;

[0129] (5) Calculate the attenuation coefficient, perform uncertainty analysis and draw error bars.

[0130] Table 6 Determination of attenuation coefficient in RB-1 standard block

[0131] Location Amplitude average value (mV) Attenuation coefficient (dB / cm) 1 70.3 1.184 2 70.7 1.165 3 70.7 1.166 4 70.6 1.171 5 70.7 1.166 6 71.0 1.154 7 70.0 1.200 8 70.6 1.171 9 70.6 1.173 10 70.3 1.188 11 70.3 1.184

[0132] The average value is 1.18dB / cm. The standard part is carbon steel. Yin Chang and other scholars measured the carbon steel attenuation coefficient at 4.5MHz signal as 1.1dB / cm, which is very close and slightly larger. It is speculated that it may be caused by the different ultrasonic frequencies. The higher the ultrasonic frequency, the greater its attenuation coefficient.

[0133] The calculation uncertainty is:

[0134]

[0135] Its expanded uncertainty is: U kδ = k × U δ =0.06(dB / cm).

[0136] In step 3, the specific operation of measuring the ultrasonic attenuation coefficient in the brass block is as follows:

[0137] (1) Take a sample point at the center of brass surface 1 and surface 2, and measure the thickness of brass surface 1 and surface 2 with a vernier caliper. Repeat ten times.

[0138] (2) Repeat steps (2)(3)(4)(5) of the experiment.

[0139] Table 7 Determination of attenuation coefficient of brass block

[0140] Thickness(mm) Amplitude average value (mV) Attenuation coefficient (dB / cm) 0 98.9 - 29.9 23.6 4.163 40.0 14.6 4.160

[0141] The average value was found to be 4.16 dB / cm.

[0142] In step 4, the specific operation of determining the optimal flaw detection frequency is as follows:

[0143] (1) Connect the dual crystal probe, signal generator, oscilloscope and computer;

[0144] (2) Place the probe directly above the wound and adjust the carrier parameters of the signal generator pulse signal from 4 MHz to 6 MHz in increments of 0.1 MHz, and record the peak-to-peak value of the wound waveform at each frequency;

[0145] (3) Repeat the above steps for four wound depths.

[0146] The peak value of the wound waveform at different depths varies with frequency. Fig.16 As shown, the experimental data show that at the same wound depth, as the sound wave frequency increases, the amplitude first increases and then decreases; when the wound depth increases, the sound wave frequency at the maximum amplitude decreases, and the optimal flaw detection frequency range decreases.

[0147] In step 4, the depth and thickness of the wound are measured according to the speed of the ultrasound. The specific operation is as follows:

[0148] (1) Sample points were marked every 4 mm above the through holes at depths of 3.5 mm, 8.5 mm, 13.5 mm, and 18.5 mm on the RB-1 standard.

[0149] (2) Repeat steps (2), (3), (4) of Experiment 1;

[0150] (3) Using WaveAnalysis waveform analysis software, measure the time difference Δt3 between the first echo of the ultrasonic wave on the upper surface of the wound of the standard component and the first echo on the bottom surface;

[0151] (4) Calculate the wound depth and wound thickness of 3.5m and 13.5mm through holes, perform uncertainty analysis and draw error bars.

[0152] The RB-1 standard test block was inspected for two wounds with depths of 3.5 mm and 13.5 mm. Fig.17 As shown in the figure. By observing the waveform, it can be seen that when the wound waveform appears, the bottom wave amplitude will decrease or even disappear. The standard error bar graph of 3.5mm wound in RB-1 is shown in the figure. Fig.18 The waveform of the continuous pulse signal detecting a 13.5 mm wound in RB-1 is shown in Fig.19The standard error bar graph of 13.5 mm wound in RB-1 is shown in Fig. 20 shown.

[0153] Table 8 Detection of 3.5 mm wounds

[0154] Position(mm) Defect to bottom surface (us) Surface to bottom (us) Average depth (mm) 4 7.36 1.24 3.59 8 7.36 1.23 3.58 12 7.35 1.24 3.61 16 7.36 1.23 3.58 20 7.36 1.23 3.59 24 7.35 1.24 3.61 28 7.35 1.24 3.61 32 7.37 1.22 3.55 36 7.37 1.22 3.54

[0155] The average wound depth was 3.58 mm.

[0156] Table 9 13.5mm wound detection

[0157] Position(mm) Defect to bottom surface (us) Surface to bottom (us) Average depth (mm) 4 3.98 4.61 13.58 8 3.99 4.60 13.55 12 3.99 4.60 13.55 16 3.99 4.60 13.57 20 3.99 4.60 13.55 24 4.00 4.59 13.55 28 4.00 4.59 13.50 32 3.99 4.60 13.51 36 4.01 4.58 13.48

[0158] The average wound size was found to be 13.53 mm.

[0159] The experimental results are highly accurate. The relative error of detecting the depth of a 3.5mm wound is 2.3%, and the relative error of detecting the depth of a 13.5mm wound is 0.2%. The detection result is very close to the actual position of the wound, and the flaw detection effect is good. The uncertainty of calculating a 3.5mm defect is 0.04mm, and the expanded uncertainty is 0.08mm. The uncertainty of calculating a 13.5mm defect is 0.06mm, and the expanded uncertainty is 0.12mm.

[0160] The standard error bar graph of wound thickness of 3.5 mm through hole in RB-1 is as follows Fig.21 As shown, the standard error bar graph of the 13.5 mm through-hole wound thickness in RB-1 is as follows Fig. 22 shown.

[0161] Table 103.5mm through hole wound thickness detection

[0162]

[0163] The average wound thickness at the 3.5mm through hole was found to be 3.07mm.

[0164] Table 1113.5mm through hole wound thickness detection

[0165]

[0166] The average wound thickness at the 13.5mm through hole is 3.08mm. The experimental results are highly accurate. The relative error of detecting the thickness of a 3.5mm wound is 2.3%, and the relative error of detecting the thickness of a 13.5mm wound is 2.7%. The detection result is very close to the actual thickness of the wound, and the flaw detection effect is good. The uncertainty of calculating the thickness of a 3.5mm deep wound is 0.03mm, and the expanded uncertainty is 0.06mm. The uncertainty of calculating the thickness of a 13.5mm deep wound is 0.03mm, and the expanded uncertainty is 006mm.

[0167] In step 4, the half-wave method is used to measure the wound width. The specific operation is as follows:

[0168] (1) Connect the dual crystal probe, signal generator, oscilloscope and computer, adjust the signal generator to output a 4-cycle pulse train electrical signal with a carrier parameter of 5 MHz and 5 Vpp sine wave;

[0169] (2) Place the dual crystal probe 3.5 mm above the center of the wound, adjust the oscilloscope until only the wound waveform is visible on the screen and the waveform is at its maximum, and record the peak-to-peak value of the wound waveform at this time;

[0170] (3) Move the dual crystal probe to the edge of the wound, adjust the oscilloscope until only the wound waveform appears on the screen, and record the peak-to-peak value of the wound waveform at this time;

[0171] (4) Compare the results measured in steps (2) and (3) and guess and determine the waveform ratio;

[0172] (5) Use the waveform ratio obtained in step (5) to find and mark the 4 mm wound edge, and use a vernier caliper to measure the distance between the two marks.

[0173] In order to determine the waveform ratio, the peak values ​​of the highest wound waveform and the edge wound waveform corresponding to four wound depths were measured respectively. Within the error range, this experiment selected a waveform ratio of 75%, which was called the three-quarter waveform method and was applied to a steel block with a 4mm wound for verification.

[0174] When detecting a 4mm cylindrical wound, the maximum peak-to-peak value of the wound waveform is 8.94mV, and the three-quarter wave height is 6.71mV.

[0175] Table 12 Determination of the edge position of a wound with a transverse diameter of 4 mm

[0176] frequency Left amplitude (mV) Right amplitude (mV) Vernier caliper reading (mm) 1 6.72 6.64 4.10 2 6.64 6.72 4.12 3 6.64 6.72 4.02 4 6.72 6.64 4.02 5 6.80 6.80 4.08 6 6.72 6.72 4.10 7 6.64 6.72 4.12 8 6.72 6.72 4.10 9 6.80 6.64 4.10 10 6.72 6.64 4.08 average value 6.71 6.70 4.08

[0177] Table 13 Detection of wounds with a transverse diameter of 4 mm

[0178]

[0179] The experimental results are highly accurate. The relative error of detecting a wound with a transverse diameter of 4mm is 2.7%. The detection result is very close to the actual width of the wound, and the flaw detection effect is good. The uncertainty of calculating a wound with a diameter of 4mm is 0.02mm, and the expanded uncertainty is 0.04mm.

[0180] In summary, the present invention realizes the basic functions of flaw detection, completes the precise positioning of the wound in the test block and the measurement of the wound size, studies the speed of sound and attenuation coefficient of sound waves propagating in different metals, and realizes application in a variety of materials.

[0181] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A detection method of an ultrasonic flaw detection device, characterized in that: The steps of the detection method are as follows: S1. Determine the ultrasonic propagation velocity in the standard part, calculate the sound velocity and the average time of ultrasonic propagation in the delay block, perform uncertainty analysis on the sound velocity and draw error bars using Matlab; S2, measuring the depth of the wound based on the speed of ultrasound; S3, measure the wound size in the standard part, make uncertainty analysis and draw error bars; S4. Determine the optimal frequency range for standard parts flaw detection; S5. Measure the ultrasonic propagation velocity in the brass block and the aluminum block, perform uncertainty analysis and draw error bars; S6. Measure the ultrasonic attenuation coefficient in the standard part, perform uncertainty analysis and draw error bars; S7. Measure the ultrasonic attenuation coefficient in the brass block and the aluminum block, perform uncertainty analysis and draw error bars.

2. The detection method of an ultrasonic flaw detection device according to claim 1, characterized in that: The calculation formula of the propagation speed of the ultrasonic wave in the standard component in step S1 is: The formula for calculating the propagation time of ultrasonic waves in the delay block is: Δt0=Δt1-Δt2; Where ν is the sound velocity of the material being tested, D is the thickness of the test block, Δt1 is the time difference between the initial ultrasonic wave and the first echo on the bottom surface of the standard part, and Δt2 is the time difference between the first and second bottom surface echoes.

3. The detection method of an ultrasonic flaw detection device according to claim 1, characterized in that: The calculation formula for the wound depth in step S2 is: Where l is the wound depth, and Δt3 is the time difference between the first echo of the ultrasonic wave on the upper surface of the wound of the standard part and the first echo on the bottom surface.

4. The detection method of an ultrasonic flaw detection device according to claim 1, characterized in that: The step S3 includes the following steps: Step 1: Repeat step S2 to measure the front and back depth values ​​of the wound to obtain the longitudinal diameter of the wound, and the calculation formula is: Where d is the wound thickness, Δt'3 is the time difference between the first bottom echo and the first wound upper surface echo after the workpiece is reversed; Step 2: Use the half-wave method to measure the transverse diameter of the wound.

5. The detection method of an ultrasonic flaw detection device according to claim 1, characterized in that: In step S5, the time difference Δt between the initial wave and the first bottom surface echo of the ultrasonic wave in the brass block and the aluminum block is measured respectively. The propagation speed ν of the ultrasonic wave in the brass block and the aluminum block is calculated as follows:

6. The detection method of an ultrasonic flaw detection device according to claim 1, characterized in that: The calculation formula for the attenuation coefficient δ of standard parts, brass blocks and aluminum blocks at a certain frequency is: Where A1 is the peak-to-peak value of the sinusoidal signal directly transmitted to the straight probe, and A2 is the peak-to-peak value of the sinusoidal signal after the ultrasonic wave passes through the standard, brass block, and aluminum block.

7. The detection method of an ultrasonic flaw detection device according to claim 1, characterized in that: The uncertainty calculation formula is: U k0 =K×U C0 ; Where U c0 is the standard uncertainty constant of the ultrasonic propagation velocity v in the workpiece, U k0 is the expanded uncertainty constant of v, k is the coverage factor, U D is the uncertainty constant of thickness D, U t2 is the uncertainty constant of the time difference Δt2.

8. The detection method of an ultrasonic flaw detection device according to claim 1, characterized in that: The pulse multiple reflection method was used to measure the sound velocity and wound depth, and the penetration method was used to measure the attenuation coefficient of the test block.

9. The detection method of an ultrasonic flaw detection device according to claim 1, characterized in that: A single dual-element probe design was used to measure the velocity of sound and wound depth; a dual-probe design was used to measure the attenuation coefficient of the test block.

10. An ultrasonic flaw detection device according to any one of claims 1 to 9, characterized in that: It includes an equipment module and a data analysis software module. The equipment module includes an oscilloscope, a function signal generator, a standard ultrasonic test block, a metal block, a dual crystal probe, a straight probe, a medical ultrasonic coupling agent, a vernier caliper, a ruler, and a probe line; the data analysis software module includes a DeviceManager virtual oscilloscope and WaveAnalysis.

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