Method for determining scanning stepping of water immersion ultrasonic detection system

Abstract

The invention discloses a method for determining scanning stepping of a water immersion ultrasonic detection system, which comprises the following steps of: 1, selecting test blocks made of different materials, finding hole waves of the test blocks, adjusting the wave height to 80% of full-screen height, moving a probe along the X-axis or Y-axis direction, reducing the wave height to 40% of FSH, and recording the current X-axis or Y-axis value as A1; 2, the probes are moved in the opposite direction to the position where the hole wave is 40% FSH, the current X-axis or Y-axis numerical value is recorded as A2, and effective acoustic beam width values are tested on multiple devices through the multiple probes; 3, drawing a static response curve, namely drawing the static response curve on the test block by adopting a plurality of probes respectively; and 4, analyzing the static response curve. According to the method, the maximum scanning stepping value which can be used on the premise that phantom waves do not appear and defects are completely detected is obtained, effective acoustic beam width values are tested for different devices and different probes, and the maximum scanning stepping value is verified.

Description

Technical Field

[0001] The invention belongs to the technical field of ultrasonic nondestructive testing, and in particular relates to a method for determining a scanning step of a water immersion ultrasonic testing system. Background Art

[0002] When conducting underwater ultrasonic testing, the general standard only requires that the scanning step should not be greater than half of the effective sound beam diameter. However, there are no clear requirements for the scanning step setting.

[0003] In the prior art, if the scanning step is set too large, it will affect the detection of defects. If the scanning step is set too small, it will cause the repetition frequency to be too high and phantom waves will appear, affecting the judgment of defects, and will also greatly reduce the detection efficiency. Summary of the invention

[0004] The present invention aims at solving the problems in the prior art and proposes the following technical solutions: A method for determining a scanning step of an immersion ultrasonic detection system, the method comprising: Step 1: Select test blocks of different materials, find the hole wave of the test block and adjust the wave height to 80% of the full screen height, move the probe along the X-axis or Y-axis direction to reduce the wave height to 40% FSH, and record the current X-axis or Y-axis value as A1; Step 2: Move the probe in the opposite direction to the point where the hole wave is 40% FSH and record the current X-axis or Y-axis value as A2; Step 3: Draw the static response curve Use multiple probes to draw static response curves on the test block; Step 4: Analyze the static response curve According to the static response curves drawn, it can be seen that the curves drawn on multiple devices all rise smoothly in the shape of a “√”.

[0005] As a preferred embodiment of the above technical solution, in step 1 and step 2, for the liquid immersion focusing probe, the effective acoustic beam width should be measured at the focus.

[0006] As a preferred embodiment of the above technical solution, the scanning interval should not be greater than half of the effective sound beam width.

[0007] As a preferred embodiment of the above technical solution, the height of the alarm gate or signal recording gate should not be higher than half of the acceptance limit.

[0008] As a preferred embodiment of the above technical solution, automatic alarm or automatic recording detection is adopted.

[0009] As a preferred embodiment of the above technical solution, the scanning interval can be appropriately relaxed while ensuring that the minimum flat-bottom hole required to be detected can be alarmed or recorded twice in succession.

[0010] As a preferred embodiment of the above technical solution, the scanning interval is relaxed to a maximum of no more than 0.7 times of the effective sound beam width.

[0011] As a preferred embodiment of the above technical solution, in step 2, multiple probes are used to test the effective sound beam width value on multiple devices respectively.

[0012] As a preferred embodiment of the above technical solution, in step 4, it can be known that the gain value required for the front surface test block is the lowest, and the energy is most concentrated in the focal column area of ​​the probe.

[0013] As a preferred embodiment of the above technical solution, the sound beam diameter at this position is the smallest, which is the effective sound beam value required to determine the scanning step.

[0014] The beneficial effects of the present invention are: 1. The maximum scanning step value that can be used without the occurrence of phantom waves and ensuring complete defect detection is obtained; 2. Tested the effective beam width value for different devices and probes and verified the maximum scanning step. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 What is shown is a schematic diagram of the sound field structure of the focusing probe in the embodiment; Figure 2 Shown is a static response curve diagram of the LS200-LP1200 device in the embodiment; Figure 3 Shown is a static response curve diagram of the SM-J7B-1000 device in the embodiment; Figure 4 What is shown is a schematic diagram of the static response amplitude on the test block in the embodiment; Figure 5 The figure shows the dynamic response amplitude and C-scan schematic diagram when the stepping is set to 1.3 mm in the embodiment; Figure 6 The figure shows the dynamic response amplitude and C scan schematic diagram when the step is set to 1.5 mm in the embodiment; Figure 7 The figure shows the dynamic response amplitude and C-scan schematic diagram when the stepping is set to 1.8 mm in the embodiment; Figure 8 The figure shows a schematic diagram of the dynamic response amplitude and C-sweep in an embodiment in which the sensitivity is increased by 6 dB and the step setting is 1.8 mm. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments.

[0017] Example Different water immersion detection equipment has different detection frequency ranges, and the actual center frequency and actual focal column diameter of different probes are also different. When the probe is combined with the equipment, the effective sound beam width of the actual detection probe is not the same. According to the provisions of HB20159 / GJB 1580A / AMS-STD-2154 and other standards, the setting of the scanning step is directly related to the size of the effective sound beam diameter, such as Figure 1 The Φ shown here represents the effective sound beam width of the focused probe, and L represents the focal column diameter of the focused probe.

[0018] In ultrasonic testing, the formation and width of the focused beam are crucial to improving detection sensitivity and accuracy. The focused beam has the highest ultrasonic signal energy at the focus, and the sound width is the shortest at the focus, while the beam width spreads and becomes larger in the area outside the focus. Therefore, in theory, the minimum beam width can be regarded as the width of the focused beam when it propagates.

[0019] The minimum beam width is calculated as follows: in: Indicates the width of the sound beam at the focus; Indicates the wavelength of ultrasound; F represents the focal length, that is, the distance from the focus to the center of the array element; A represents the total length of the array element chip.

[0020] like Figure 1-Figure 8 As shown, a method for determining a scanning step of an immersion ultrasonic detection system, the method comprising: Step 1: Test the effective sound beam width of the two most commonly used test frequencies in actual testing, 5MHz (IX0519GB) and 10MHz (IS1010GA). The test method is to select test blocks of different materials, find the hole wave of the test block and adjust the wave height to 80% of the full screen height, move the probe along the X-axis or Y-axis direction, and drop the wave height to 40% FSH. Record the current X-axis or Y-axis value as A1.

[0021] Step 2: Move the probe in the opposite direction to the point where the hole wave is 40% FSH and record the current X-axis or Y-axis value as A2. Use different probes to test the effective sound beam width value on imported and domestic equipment respectively.

[0022] As shown in the following table: Table 1 Test values ​​of effective sound beam width of 5MHz flat probe of imported equipment Table 2 Test values ​​of effective sound beam width of 5MHz focused probe of imported equipment Table 3 Test values ​​of effective sound beam width of 10MHz focused probe of imported equipment Table 4 Test values ​​of effective sound beam width of 5MHz focused probe of domestic equipment Table 5 Test values ​​of effective sound beam width of 10MHz focused probe of domestic equipment Step 3: Draw the static response curve The static response curves were drawn on the BT9-Φ0.8mm test block using the IX0519GB probe and the IS1010GA probe respectively.

[0023] According to the state of the measurement in the measurement or control process, there are static and dynamic differences, so the input and output characteristics of the sensor are divided into static characteristics and dynamic characteristics.

[0024] Static characteristics refer to the relationship between the sensor output and the input signal under the action of the input signal in a steady state (when the input quantity is constant or changes very slowly), which is generally expressed by a curve, mathematical expression or table.

[0025] Without considering factors such as hysteresis, creep (the phenomenon that the strain of a solid material increases with time while the stress remains constant) and instability, the static characteristics of the sensor can be expressed by a polynomial equation: Where: y is the output of the sensor x is the input of the sensor a 0 Zero output a 1 The sensitivity at zero point a n —n>1, nonlinear term coefficient The static characteristic curve of the sensor can be obtained through actual testing. The main parameters for measuring static characteristics include measurement range, linearity, sensitivity, resolution, hysteresis, repeatability, stability, etc.

[0026] Step 4: Analyze the static response curve According to the static response curve, it can be seen that the curves drawn on the imported and domestic equipment are both rising smoothly in the shape of "√". It can be seen that the gain value required for the front surface test block is the lowest. The energy is most concentrated at this position, which is the focal column area of ​​the probe. The sound beam diameter at this position is the smallest, which is the effective sound beam value required to determine the scanning step.

[0027] The diameter of the focal column is a distance parameter. When the ratio of the sound pressure at any point at a distance of from the focus to the sound pressure at the focus itself is -6dB, it means that the ball has deviated from the axis by twice the distance.

[0028] When the focal column length L is the ratio of the sound pressure at any point on the focal line to the sound pressure at the focal position, it is -6dB, which means that the ball has deviated from the focal point by twice the distance.

[0029] Test the dynamic response of different devices and probes at different radii Dynamic response generally refers to the response of the control system's output from the initial state to the final state under the action of a typical input signal.

[0030] When a unit step input x(t) is added to a certain link (system), its response y(t) begins to gradually rise until it stabilizes at a certain value.

[0031] The LS200-LP1200 equipment is designed to detect a diameter of 1200mm, and the maximum detectable range of products is 1100mm. Dynamic response tests are performed at R=550mm and R=400mm respectively. The scanning step of the IX0519GB probe is set to 1.2mm, and the scanning step of the IS1010GA probe is set to 0.6mm.

[0032] Table 6 Dynamic response test of different probes, different diameters and different test blocks of LS200-LP1200 equipment The SM-J7B-1000 equipment is designed to detect a diameter of 1000mm, and the maximum detectable range of products is 900mm. Dynamic response tests are performed at R=450mm and R=300mm respectively. The scanning step of the IX0519GB probe is set to 1.2mm, and the scanning step of the IS1010GA probe is set to 0.6mm.

[0033] Table 7 Dynamic response test of different probes, different diameters and different test blocks of SM-J7B-1000 equipment In step 1 and step 2, according to the provisions of HB 20159, GJB 1580A, and AMS-STD-2154, for liquid-immersed focused probes, the effective sound beam width should be measured at the focus, and the scanning interval should not be greater than half of the effective sound beam width. At this time, the height of the alarm gate or signal recording gate should not be higher than half of the acceptance limit.

[0034] When using automatic alarm or automatic recording detection, the scanning interval can be appropriately relaxed while ensuring that the minimum flat-bottom hole required to be detected can be alarmed or recorded twice in succession, but the maximum should not exceed 0.7 times the effective sound beam width.

[0035] Dynamic response scanning tests were performed on Ti6Al4V-Ф0.4mm test blocks using 1.3mm, 1.5mm, and 1.8mm diameters, respectively. The sound beam diameter in the X direction of IX0519GB (H43001) was measured to be 545.246-542.518=2.7mm using the 6dB method on a test block with a burial depth of 6.3mm. The static scanning waveform is shown in the figure below. Figure 4 shown.

[0036] The repetition frequency is set to 900Hz, the scanning speed is set to 20r / min, the scanning step is set to 1.3mm, and the Ti6Al4V-Ф0.4mm test block with a buried depth of 6.3mm is dynamically scanned. The defect display amplitude height is 76.86%, such as Figure 5 shown.

[0037] The repetition frequency is set to 900Hz, the scanning speed is set to 20r / min, the scanning step is set to 1.5mm, and the Ti6Al4V-Ф0.4mm test block with a buried depth of 6.3mm is dynamically scanned. The defect display amplitude height is 73.73%, such as Figure 6 shown.

[0038] The repetition frequency is set to 900Hz, the scanning speed is set to 20r / min, the scanning step is set to 1.8mm, and the Ti6Al4V-Ф0.4mm test block with a buried depth of 6.3mm is dynamically scanned. The defect display amplitude height is 77.65%, such as Figure 7 shown.

[0039] The repetition frequency is set to 900Hz, the scanning speed is set to 20r / min, the scanning step is set to 1.8mm, and the sensitivity is adjusted to increase by 6dB to perform dynamic scanning of the Ti6Al4V-Ф0.4mm test block with a buried depth of 6.3mm. The defect display amplitude height is ≥100%, such as Figure 8 shown.

[0040] The repetition frequency is set to 900Hz, the scanning speed is set to 20r / min, and the dynamic response scanning of 1.3mm, 1.5mm, and 1.8mm on the Ti6Al4V-Ф0.4mm test block with a burial depth of 6.3mm can effectively find the defect display, which can ensure the reliability of the inspection. In addition, under the premise of ensuring sufficient signal-to-noise ratio, improving the 6dB scanning can obtain better dynamic scanning results.

[0041] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them.

Claims

1. A method for determining a scanning step of an immersion ultrasonic detection system, the method comprising: Step 1: Select test blocks of different materials, find the hole wave of the test block and adjust the wave height to 80% of the full screen height, move the probe along the X-axis or Y-axis direction to reduce the wave height to 40% FSH, and record the current X-axis or Y-axis value as A1; Step 2: Move the probe in the opposite direction to the point where the hole wave is 40% FSH and record the current X-axis or Y-axis value as A2; Step 3: Draw the static response curve Use multiple probes to draw static response curves on the test block; Step 4: Analyze the static response curve According to the static response curves drawn, it can be seen that the curves drawn on multiple devices all rise smoothly in the shape of a "√".

2. A method for determining a scanning step of an immersion ultrasonic detection system according to claim 1, characterized in that: In steps 1 and 2, for liquid-immersion focused transducers, the effective beam width should be measured at the focal point.

3. A method for determining a scanning step of an immersion ultrasonic detection system according to claim 2, characterized in that: The scanning interval should not be greater than half of the effective sound beam width.

4. A method for determining a scanning step of an immersion ultrasonic detection system according to claim 3, characterized in that: The height of the alarm gate or signal recording gate should not be higher than half of the acceptance limit.

5. The method for determining the scanning step of an immersion ultrasonic detection system according to claim 3, characterized in that: Use automatic alarm or automatic recording detection.

6. A method for determining a scanning step of an immersion ultrasonic detection system according to claim 5, characterized in that: Under the condition that the minimum flat-bottom hole required to be detected can be alarmed or recorded twice in succession, the scanning interval can be appropriately relaxed.

7. A method for determining a scanning step of an immersion ultrasonic testing system according to claim 6, characterized in that: The maximum scanning interval shall not exceed 0.7 times the effective sound beam width.

8. The method for determining the scanning step of an immersion ultrasonic detection system according to claim 1, characterized in that: In step 2, multiple probes are used to test the effective beam width value on multiple devices.

9. The method for determining the scanning step of an immersion ultrasonic detection system according to claim 1, characterized in that: In step 4, it can be seen that the gain value required for the front surface test block is the lowest, and the energy is most concentrated in the focal column area of ​​the probe.

10. A method for determining a scanning step of an immersion ultrasonic testing system according to claim 9, characterized in that: The sound beam diameter at this position is the smallest, which is the effective sound beam value required to determine the scanning step.

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