Reference block group for ultrasonic detection of brazing type copper-aluminum transition equipment wire clamp and calibration method of reference block group

Abstract

The invention relates to a reference block group for ultrasonic detection of a brazing type copper-aluminum transition equipment wire clamp and a calibration method of the reference block group, and belongs to the technical field of nondestructive detection. The test block group comprises three independent test blocks, each test block is formed by connecting an aluminum plate layer and a copper plate layer through a brazing process, the area of the copper plate layer is smaller than that of the aluminum plate layer, one test block is provided with four through holes with different diameters on the aluminum plate layer, and the other test block is provided with corresponding through holes on the copper plate layer. The third test block is pre-embedded with an air domain at the copper-aluminum bonding surface to simulate an incomplete fusion defect, and a standard reflection signal database is established by accurately controlling the size of the test block and the position and form of the defect and combining ultrasonic detection, so that the accuracy, the reliability and the repeatability of ultrasonic detection can be effectively improved, and the test efficiency is improved. And a technical support is provided for quality control and safety evaluation of the brazing type copper-aluminum transition equipment wire clamp.

Description

Technical Field

[0001] This invention belongs to the field of nondestructive testing technology, and in particular relates to a set of comparative test blocks and its calibration method for ultrasonic testing of wire clamps in brazed copper-aluminum transition equipment. Background Technology

[0002] Brazed copper-aluminum transition clamps are widely used in power systems to connect copper and aluminum conductors. Due to their dissimilar material connection characteristics, the brazed interface is prone to defects such as incomplete fusion, porosity, and cracks, affecting the reliability and safety of the connection. Ultrasonic testing is an important means of evaluating the quality of such components; however, there is currently a lack of standardized test blocks specifically designed for this type of structure, leading to poor consistency in test results and difficulties in quantifying defects. Existing test blocks are mostly designed based on homogeneous materials, which suffers from insufficient simulation capabilities and a lack of calibration methods, making it difficult to accurately reflect the acoustic characteristics and defect morphology of the copper-aluminum transition zone, thus limiting the accuracy and reliability of the test. Summary of the Invention

[0003] This invention provides a set of comparative test blocks and its calibration method for ultrasonic testing of wire clamps in brazed copper-aluminum transition equipment, in order to solve the problems of insufficient test block simulation capability and lack of calibration method in the prior art.

[0004] The technical solution adopted in this invention is as follows: it includes an aluminum-side hole comparison test block, a copper-side hole comparison test block, and a bonding non-fusion defect comparison test block. The three test blocks are independent test blocks. Each test block includes an aluminum plate layer and a copper plate layer brazed to the surface of the aluminum plate layer. The area of ​​the copper plate layer is smaller than the area of ​​the aluminum plate layer. The aluminum-side hole comparison test block and the copper-side hole comparison test block also include a single cylindrical clamp. The bonding non-fusion defect comparison test block includes a double cylindrical clamp. A through hole is provided on the aluminum plate layer of the aluminum-side hole comparison test block. A through hole is provided on the copper plate layer of the copper-side hole comparison test block. An air zone is pre-embedded at the copper-aluminum bonding surface of the bonding non-fusion defect comparison test block.

[0005] The aluminum plate layer of the aluminum side hole comparison test block of the present invention has a thickness d of 10 mm and a copper plate layer thickness d of 1 mm. The width W of the aluminum plate layer and the copper plate layer is 100 mm. The length L1 of the aluminum plate layer is 100 mm and the length L2 of the copper plate layer is 80 mm. The top end face of the aluminum plate layer and the top end face of the copper plate layer are on the same vertical plane. A single cylindrical clamp is connected to the rear of the aluminum plate layer.

[0006] The aluminum plate layer of the present invention is provided with four through holes with diameters of 8mm, 4mm, 3mm and 2mm respectively. The distance from the center of each through hole to any edge of the copper plate layer is not less than 20mm, and the distance between the centers of adjacent through holes is not less than 30mm.

[0007] The thickness d of the aluminum plate layer of the copper side hole comparison test block of the present invention is 10mm, the thickness d of the copper plate layer is 1mm, the width W of the aluminum plate layer and the copper plate layer is 100mm, the length of the aluminum plate layer L1 is 100mm, the length of the copper plate layer L2 is 80mm, the top end face of the aluminum plate layer and the top end face of the copper plate layer are on the same vertical plane, and a single cylindrical wire clamp is connected to the rear of the aluminum plate layer.

[0008] The copper plate layer of the present invention is provided with four through holes with diameters of 8mm, 4mm, 3mm and 2mm respectively. The distance from the center of each through hole to any edge of the copper plate layer is not less than 20mm, and the distance between the centers of adjacent through holes is not less than 30mm.

[0009] The aluminum plate layer thickness d of the comparative test block for unfused defects described in this invention is 10mm, the copper plate layer thickness d is 1mm, the width W of both the aluminum plate layer and the copper plate layer is 100mm, the length L1 of the aluminum plate layer is 100mm, the length L2 of the copper plate layer is 80mm, the top end face of the aluminum plate layer and the top end face of the copper plate layer are on the same vertical plane, and the rear part of the aluminum plate layer is connected to a double cylindrical wire clamp.

[0010] The present invention relates to a pre-embedded air gap region at the copper-aluminum interface of a comparative test block for incomplete fusion defects. The air gap region, measured from the top, has a width of 50 mm, a length of 35 mm, and a depth d1 of 0.1 mm to 0.3 mm, and is used to simulate incomplete fusion defects.

[0011] The surface roughness Ra of all surfaces of the aluminum-side hole comparison test block, the copper-side hole comparison test block, and the bonding non-fusion defect comparison test block described in this invention is ≤ 6.3μm, and the dimensional tolerance of each part does not exceed ±0.1mm.

[0012] The aluminum-side hole comparison test block, copper-side hole comparison test block, and bonding non-fusion defect comparison test block of the present invention have no burrs on their edges and no opening defects on the edges of the through holes.

[0013] A calibration method for a set of comparative test blocks for ultrasonic testing of wire clamps in brazed copper-aluminum transition equipment includes the following steps: (1) Precision fabrication of aluminum side hole comparison test blocks, copper side hole comparison test blocks and bonding incomplete fusion defect comparison test blocks; (2) Calibrate the three types of test blocks; A pulse-echo ultrasonic flaw detector is used, equipped with a 5MHz~15MHz high-frequency dual-crystal probe or a focusing probe. The coupling agent is glycerin or a special ultrasonic coupling agent, as detailed below: 1) Intact bonding area calibration: Scan the defect-free areas of the three test blocks made in step (1) respectively, and record their typical waveform characteristics as a reference; 2) Hole defect identification: Scan the four through holes on the aluminum plate layer of the aluminum side comparison block; scan the four through holes on the copper plate layer of the copper side comparison block; record the waveform characteristics of each. 3) Unbonded area calibration: Scan the air gap area of ​​the comparative test block with unbonded defects and record its waveform characteristics; (3) Establish a standard reflection signal database based on the reflection signal, and record the reflection amplitude, time-domain waveform, sound path and defect equivalent parameters of each defect to form a defect map that can be used for actual detection and comparison.

[0014] The advantages of this invention are that the comparative test block group includes three test blocks, which respectively simulate aluminum-side holes, copper-side holes, and interface non-fusion defects. The test block structure is reasonably designed, the defect size and location are strictly controlled, and the surface roughness and dimensional accuracy meet the requirements of high-precision testing.

[0015] The calibration method described above can establish a standard reflection signal database, enabling performance verification, sensitivity calibration, and quantitative analysis of defects in ultrasonic testing equipment, thereby significantly improving the reliability and comparability of test results. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the aluminum side hole comparison test block of the present invention; Figure 2 yes Figure 1 The left view; Figure 3 This is a schematic diagram of the structure of the copper-side hole comparison test block of the present invention; Figure 4 yes Figure 3 The left view; Figure 5 This is a schematic diagram of the structure of the comparative test block for incomplete fusion defects in this invention; Figure 6 yes Figure 5 The left view; Figure 7 Waveform diagram of the welded area on the aluminum side; Figure 8 Waveform diagram of the welded area on the copper side; Figure 9 Waveform diagram of weld hole defect area detected on aluminum side; Figure 10 Waveform diagram of the defective area of ​​welded holes on the copper side; Figure 11 Waveform diagram of weld desoldering defect area detected on the aluminum side; Figure 12 Waveform diagram of the weld desoldering defect area detected on the copper side. Detailed Implementation

[0017] The test block includes an aluminum-side hole comparison test block 1, a copper-side hole comparison test block 2, and a bonding incomplete fusion defect comparison test block 3. The three test blocks are independent test blocks. Each test block includes an aluminum plate layer and a copper plate layer brazed to the surface of the aluminum plate layer. The area of ​​the copper plate layer is smaller than the area of ​​the aluminum plate layer. The aluminum-side hole comparison test block 1 and the copper-side hole comparison test block 2 also include a single cylindrical clamp, while the bonding incomplete fusion defect comparison test block 3 includes a double cylindrical clamp. A through hole is provided on the aluminum plate layer of the aluminum-side hole comparison test block 1, and a through hole is provided on the copper plate layer of the copper-side hole comparison test block 2. An air zone is pre-embedded at the copper-aluminum bonding surface of the bonding incomplete fusion defect comparison test block 3.

[0018] The aluminum plate layer 101 of the aluminum side hole comparison test block 1 of the present invention has a thickness d of 10mm and a copper plate layer 102 has a thickness d of 1mm. The width W of the aluminum plate layer 101 and the copper plate layer 102 is 100mm. The length L1 of the aluminum plate layer 101 is 100mm and the length L2 of the copper plate layer 102 is 80mm. The top end face of the aluminum plate layer 101 and the top end face of the copper plate layer 102 are on the same vertical plane. The rear part of the aluminum plate layer 101 is connected to a single cylindrical wire clamp 104.

[0019] The aluminum plate layer 101 of the present invention is provided with four through holes 103, with diameters of 8mm, 4mm, 3mm and 2mm respectively. The distance from the center of each through hole 103 to any edge of the copper plate layer 102 is not less than 20mm, and the distance between the centers of adjacent through holes is not less than 30mm.

[0020] The thickness d of the aluminum plate layer 201 of the copper side hole comparison test block 2 of the present invention is 10mm, the thickness d of the copper plate layer 202 is 1mm, the width W of the aluminum plate layer and the copper plate layer is 100mm, the length of the aluminum plate layer L1 is 100mm, the length of the copper plate layer L2 is 80mm, the top end face of the aluminum plate layer and the top end face of the copper plate layer are on the same vertical plane, and the rear part of the aluminum plate layer 201 is connected to a single cylindrical wire clamp 204.

[0021] The copper plate layer 202 of the present invention is provided with four through holes 203, with diameters of 8mm, 4mm, 3mm and 2mm respectively. The distance from the center of each through hole to any edge of the copper plate layer is not less than 20mm, and the distance between the centers of adjacent through holes is not less than 30mm.

[0022] In the present invention, the aluminum plate layer 301 of the comparative test block 3 for unfused defects has a thickness d of 10 mm, the copper plate layer 302 has a thickness d of 1 mm, the width W of both the aluminum plate layer and the copper plate layer is 100 mm, the length L1 of the aluminum plate layer is 100 mm, the length L2 of the copper plate layer is 80 mm, the top end face of the aluminum plate layer and the top end face of the copper plate layer are on the same vertical plane, and the rear part of the aluminum plate layer 301 is connected to the double cylindrical clamp 304.

[0023] The present invention relates to an air gap region 303 pre-embedded at the copper-aluminum interface of the comparative test block 3 for incomplete fusion defects. The air gap region is 50 mm wide, 35 mm long, and d1 deep (0.1 mm ~ 0.3 mm) from the top, and is used to simulate incomplete fusion defects.

[0024] The surface roughness Ra of all surfaces of the aluminum side hole comparison test block 1, the copper side hole comparison test block 2, and the bonding non-fusion defect comparison test block 3 described in this invention is ≤ 6.3μm, and the dimensional tolerance of each part does not exceed ±0.1mm.

[0025] The aluminum-side hole comparison test block 1, the copper-side hole comparison test block 2, and the bonding non-fusion defect comparison test block 3 of the present invention have no burrs on their edges and no opening defects on the edges of the through holes.

[0026] A calibration method for a set of comparative test blocks for ultrasonic testing of wire clamps in brazed copper-aluminum transition equipment includes the following steps: (1) Precision fabrication of aluminum side hole comparison test block 1, copper side hole comparison test block 2 and bonding incomplete fusion defect comparison test block 3; (2) Calibrate the three types of test blocks; A pulse-echo ultrasonic flaw detector is used, equipped with a 5MHz~15MHz high-frequency dual-crystal probe or a focusing probe. The coupling agent is glycerin or a special ultrasonic coupling agent, as detailed below: 1) Intact bonding area calibration: Scan the defect-free areas of the three test blocks made in step (1) respectively, and record their typical waveform characteristics as a reference; 2) Hole defect identification: Scan the four through holes on the aluminum plate layer of the aluminum side comparison test block 1; scan the four through holes on the copper plate layer 202 of the copper side comparison test block 2; record the waveform characteristics of each. 3) Unbonded area calibration: Scan the air gap area of ​​the unbonded defect comparison block 3 and record its waveform characteristics; (3) Establish a standard reflection signal database based on the reflection signal, and record the reflection amplitude, time-domain waveform, sound path and defect equivalent parameters of each defect to form a defect map that can be used for actual detection and comparison.

[0027] The invention will be further illustrated below with specific experimental examples.

[0028] (1) Precision manufacturing of aluminum side hole comparison test block 1, copper side hole comparison test block 2 and bonding non-fusion defect comparison test block 3 in the specific implementation method; 1) Fabrication of aluminum side hole comparison test block 1: Industrial pure aluminum plate with a thickness of 10mm ± 0.1mm and pure copper plate with a thickness of 1mm ± 0.05mm were selected and metallurgically bonded using brazing. Flat-bottomed holes with diameters of Φ8mm, Φ4mm, Φ3mm, and Φ2mm were machined into the aluminum plate layer, with a hole diameter tolerance of ±0.05mm, a hole center distance from the edge ≥20mm, a hole spacing ≥30mm, and the hole axis perpendicular to the plate surface (see...). Figure 1 , 2 ).

[0029] 2) Fabrication of copper side hole comparison test block 2: The material specifications are the same as those of the aluminum side hole comparison test block. Flat-bottomed holes of the same specifications as those in the aluminum side hole comparison test block are machined at the corresponding positions on the copper plate layer (see...). Figure 3 , 4 ).

[0030] 3) Fabrication of a comparative test block 3 for unbonded defects: A rectangular groove with a depth of 0.1mm~0.3mm, a width of 50mm, and a length of 35mm was machined on the bonding surface of the aluminum plate layer using wire cutting. This groove was then brazed to the copper plate layer to form a precisely dimensional air gap defect, used to simulate a completely unbonded interface state (see...). Figure 5 , 6 ).

[0031] After each test block was fabricated, the surface roughness Ra ≤ 6.3 μm, and penetrant testing confirmed that there were no surface defects. (2) Calibrate the three types of test blocks; A pulse-echo ultrasonic flaw detector is used, equipped with a 5MHz~15MHz high-frequency dual-crystal probe or a focusing probe. The coupling agent is glycerin or a special ultrasonic coupling agent, as detailed below: 1) Intact bonding area calibration: Scan the defect-free areas of the three test blocks made in step (1) respectively, and record their typical waveform characteristics as a reference; In this area, the ultrasonic waves fully penetrate the brazing interface, with clear echoes on the bottom surface and an amplitude not less than 50% of the full screen height, while the interface echoes do not exceed 15% of the full screen height (see [reference]). Figure 7 ,8); 2) Hole defect identification: Scan the four through holes on the aluminum plate layer of the aluminum side comparison test block 1; scan the four through holes on the copper plate layer 202 of the copper side comparison test block 2, and record their respective waveform characteristics; this area shows the coexistence of interface echo and bottom surface echo, and the bottom surface echo amplitude shows a regular decrease due to defect obstruction (see Figure 9 ,10); 3) Unbonded area calibration: Scan the air gap area of ​​the unbonded defect comparison block 3 and record its waveform characteristics; this area is characterized by strong ultrasonic reflection at the interface, complete disappearance or significant reduction of the bottom surface echo, strong interface echo, and a single high-amplitude interface echo on the aluminum side; the copper side shows multiple interface echoes with non-exponential decay (see...). Figure 11 ,12); (3) The established standard reflection signal database includes the reflection amplitude, time-domain waveform, sound path and defect equivalent parameters of each defect, forming a defect map that can be used for actual detection and comparison.

[0032] (4) Inspection and quality assessment of actual workpieces Taking the factory inspection of a certain model JLX-84A brazed copper-aluminum equipment clamp as an example, the specific steps are as follows: 1) Equipment calibration and verification The USM-100 ultrasonic flaw detector and the 10MHz dual-crystal straight probe were calibrated using three comparative test blocks prepared in this experimental example: Sensitivity calibration: First, scan the Φ2mm flat-bottomed hole of the aluminum side hole comparison test block 1, adjust the instrument gain so that the echo amplitude of the hole reaches exactly 80% of the full screen height, and use this state as the benchmark detection sensitivity.

[0033] Performance Verification: Subsequently, the system performance was verified at this sensitivity: the intact area was scanned to confirm that the bottom surface echo amplitude was ≥50% and the interface echo amplitude was ≤15%; the comparative test block 3 with incomplete fusion defects was scanned to confirm that the interface echo amplitude was ≥80% and the bottom surface echo disappeared. Only after the system performance met the requirements could the actual workpiece be inspected.

[0034] 2) Defect detection and identification Perform a 100% scan on the copper-aluminum composite rod of the JLX-84A clamp. The probe moves along a spiral line on the outer wall of the rod, and the scanning speed is no more than 50 mm / s to ensure full coverage without any omissions.

[0035] When scanning to a distance of 35mm from the end, a suspicious signal was acquired. Its waveform characteristics were: a single high-amplitude interface echo (amplitude reaching 85% of the full screen height) appeared when incident on the aluminum side, while the bottom echo completely disappeared (amplitude <5%). Real-time comparison of this waveform with the established standard database revealed that it matched the standard waveform for "unbonded area (detached solder) - aluminum side" in the database. Figure 11 Based on the highly consistent characteristics, it was initially determined that there was an area-type non-fusion defect at this location.

[0036] 3) Quantitative Defects For the identified incomplete fusion defects, precise dimensional measurements were performed; Quantitative method: The relative amplitude method was used to determine the defect boundary.

[0037] Specific operation: First, move the probe to find the maximum value of the defect echo (amplitude 85%) and mark it as point O. Then, with point O as the center, slowly move the probe along the axial and circumferential directions of the bar. Monitor the echo amplitude. When the amplitude drops to 20% of the maximum value (i.e., 85% × 20% = 17%, approximately equal to 17% of the full screen height), stop moving and mark this position as boundary points A, B, C, and D.

[0038] Results: Connecting the boundary points forms an approximately elliptical region on the projection plane. Measurements show that the maximum axial length of this region is approximately 8.5 mm, and the maximum circumferential width is approximately 4.2 mm. Based on this, the equivalent area of ​​the unfused defect is calculated to be approximately 28 mm².

[0039] 4) Quality assessment The above test result, namely "the existence of one non-fusion defect with an equivalent area of ​​28 mm²", was compared with the established acceptance standard for this product. According to this standard, the area of ​​a single non-fusion defect at the brazed interface must not exceed 50 mm². In this example, the defect area (28 mm²) meets the requirement. Furthermore, the defect area (28 mm²) is less than the limit requirement, and no other defects were observed in other areas of the workpiece.

[0040] Final assessment conclusion: The ultrasonic test results of the JLX-84A brazed copper-aluminum equipment clamp meet the technical specifications and are deemed qualified.

Claims

1. A set of comparative test blocks for ultrasonic testing of wire clamps in brazed copper-aluminum transition equipment, characterized in that: The test includes an aluminum-side hole comparison test block, a copper-side hole comparison test block, and a bonding incomplete fusion defect comparison test block. These three test blocks are independent of each other. Each test block includes an aluminum plate layer and a copper plate layer brazed to the surface of the aluminum plate layer. The area of ​​the copper plate layer is smaller than that of the aluminum plate layer. The aluminum-side hole comparison test block and the copper-side hole comparison test block also include a single cylindrical clamp, while the bonding incomplete fusion defect comparison test block includes a double cylindrical clamp. A through hole is provided on the aluminum plate layer of the aluminum-side hole comparison test block, and a through hole is provided on the copper plate layer of the copper-side hole comparison test block. An air zone is pre-embedded at the copper-aluminum bonding surface of the bonding incomplete fusion defect comparison test block.

2. The comparative test block set for ultrasonic testing of wire clamps in brazed copper-aluminum transition equipment according to claim 1, characterized in that: The thickness d of the aluminum plate layer of the aluminum side hole comparison test block is 10mm, the thickness d of the copper plate layer is 1mm, the width W of the aluminum plate layer and the copper plate layer is 100mm, the length L1 of the aluminum plate layer is 100mm, and the length L2 of the copper plate layer is 80mm. The top end face of the aluminum plate layer and the top end face of the copper plate layer are on the same vertical plane, and a single cylindrical clamp is connected to the rear of the aluminum plate layer.

3. The comparative test block set for ultrasonic testing of wire clamps in brazed copper-aluminum transition equipment according to claim 2, characterized in that: The aluminum plate layer has four through holes with diameters of 8mm, 4mm, 3mm and 2mm respectively. The distance from the center of each through hole to any edge of the copper plate layer is not less than 20mm, and the distance between the centers of adjacent through holes is not less than 30mm.

4. The comparative test block set for ultrasonic testing of wire clamps in brazed copper-aluminum transition equipment according to claim 1, characterized in that: The thickness d of the aluminum plate layer of the copper side hole comparison test block is 10mm, the thickness d of the copper plate layer is 1mm, the width W of the aluminum plate layer and the copper plate layer is 100mm, the length of the aluminum plate layer L1 is 100mm, the length of the copper plate layer L2 is 80mm, the top end face of the aluminum plate layer and the top end face of the copper plate layer are on the same vertical plane, and the rear part of the aluminum plate layer is connected to a single cylindrical wire clamp.

5. A comparative test block set for ultrasonic testing of wire clamps in brazed copper-aluminum transition equipment according to claim 4, characterized in that: The copper plate layer is provided with four through holes with diameters of 8mm, 4mm, 3mm and 2mm respectively. The distance from the center of each through hole to any edge of the copper plate layer is not less than 20mm, and the distance between the centers of adjacent through holes is not less than 30mm.

6. A comparative test block set for ultrasonic testing of wire clamps in brazed copper-aluminum transition equipment according to claim 1, characterized in that: The aluminum plate layer thickness d of the combined non-fusion defect comparison test block is 10mm, the copper plate layer thickness d is 1mm, the width W of both the aluminum plate layer and the copper plate layer is 100mm, the length L1 of the aluminum plate layer is 100mm, the length L2 of the copper plate layer is 80mm, the top end face of the aluminum plate layer and the top end face of the copper plate layer are on the same vertical plane, and the rear part of the aluminum plate layer is connected to a double cylindrical clamp.

7. A comparative test block set for ultrasonic testing of wire clamps in brazed copper-aluminum transition equipment according to claim 6, characterized in that: The air gap region at the copper-aluminum interface of the comparative test block with incomplete fusion defects is pre-embedded. The air gap region is calculated from the top, with a width of 50 mm, a length of 35 mm, and a depth d1 of 0.1 mm to 0.3 mm, and is used to simulate incomplete fusion defects.

8. A comparative test block set for ultrasonic testing of wire clamps in brazed copper-aluminum transition equipment according to claim 1, characterized in that: The surface roughness Ra of all surfaces of the aluminum-side hole comparison test block, the copper-side hole comparison test block, and the bonding non-fusion defect comparison test block is ≤ 6.3μm, and the dimensional tolerance of each part does not exceed ±0.1mm.

9. A comparative test block set for ultrasonic testing of wire clamps in brazed copper-aluminum transition equipment according to claim 1, characterized in that: The edges of the aluminum-side hole comparison test block, the copper-side hole comparison test block, and the bonding non-fusion defect comparison test block are free of burrs, and the edges of the through holes are free of opening defects.

10. A calibration method for a set of comparative test blocks for ultrasonic testing of wire clamps in brazed copper-aluminum transition equipment as described in any one of claims 1 to 9, characterized in that, Includes the following steps: (1) Precision fabrication of aluminum side hole comparison test blocks, copper side hole comparison test blocks and bonding incomplete fusion defect comparison test blocks; (2) Calibrate the three types of test blocks; A pulse-echo ultrasonic flaw detector is used, equipped with a 5MHz~15MHz high-frequency dual-crystal probe or a focusing probe. The coupling agent is glycerin or a special ultrasonic coupling agent, as detailed below: 1) Intact bonding area calibration: Scan the defect-free areas of the three test blocks made in step (1) respectively, and record their typical waveform characteristics as a reference; 2) Hole defect identification: Scan the four through holes on the aluminum plate layer of the aluminum side comparison block; scan the four through holes on the copper plate layer of the copper side comparison block; record the waveform characteristics of each. 3) Unbonded area calibration: Scan the air gap area of ​​the comparative test block with unbonded defects and record its waveform characteristics; (3) Establish a standard reflection signal database based on the reflection signal, and record the reflection amplitude, time-domain waveform, sound path and defect equivalent parameters of each defect to form a defect map that can be used for actual detection and comparison.

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