Rocket tank aluminum alloy weld ultrasonic phased array detection and calibration method

Abstract

The application provides a rocket tank aluminum alloy weld joint ultrasonic phased array detection and calibration method, comprising the following steps: S1, starting the equipment; S2, gain adjustment; S3, energy distribution test; S4, detection capability test; S5, weld front scanning; S6, detection data storage; S7, gain verification; S8, energy distribution verification; S9, detection capability verification; S10, detection end. The application is innovative and optimized from two aspects of ultrasonic phased array performance test block design and process parameters, and realizes the ultrasonic phased array detection and calibration of large-thickness 2219 aluminum alloy rocket tank friction stir welding weld joints.

Description

Technical Field

[0001] This invention belongs to the field of ultrasonic phased array testing, and in particular relates to an ultrasonic phased array testing and calibration method for aluminum alloy welds in rocket propellant tanks. Background Technology

[0002] With the advancement of China's lunar exploration program, higher requirements have been placed on the thrust, payload, and reliability of the new generation of manned launch vehicles. The propellant tank is the source of the rocket's power and is directly related to thrust and payload; greater thrust requires a larger volume propellant tank. Therefore, the thickness of the propellant tanks for the new generation of manned launch vehicles has also increased significantly. The maximum weld thickness is nearly 30mm, twice the weld thickness of existing launch vehicle propellant tanks. To reduce its own weight and effectively increase payload, the propellant tanks of the new generation of manned launch vehicles will be manufactured using friction stir welding technology, which offers superior joint performance. During the welding process, due to factors such as equipment fluctuations and changes in temperature and humidity, defects such as voids, weak bonds, incomplete penetration, and cracks may appear in the friction stir weld. If the rocket carries these defects during its flight mission, it may lead to major accidents such as propellant tank leakage. Ultrasonic phased array testing technology can effectively detect the internal quality of the friction stir weld of 2219 aluminum alloy, eliminate safety hazards, and effectively improve product reliability. However, the weld thickness of the new generation of manned launch vehicles is over 20mm, which exceeds the current range of ultrasonic phased array testing capabilities (3-15mm). Therefore, developing a highly reliable ultrasonic phased array testing method for the friction stir weld of thick 2219 aluminum alloy propellant tanks is crucial to ensuring the successful flight of the new generation of manned launch vehicles.

[0003] Ultrasonic phased array testing technology is a novel testing technique based on the principle of ultrasonic testing. The ultrasonic phased array testing equipment converts electrical signals into ultrasonic waves through transducers. After the ultrasonic waves enter the workpiece, they are reflected at the defect interface or workpiece surface. The reflected ultrasonic waves are received by the transducer and converted back into electrical signals. The equipment forms a three-dimensional image based on the amplitude and time differences of the received electrical signals, which is used to assess the location and magnitude of defects. In industries such as pressure vessels, where products are joined using fusion welding technology, a sector-scanning method is generally chosen for ultrasonic phased array testing of the weld seams. However, practice has shown that sector-scanning has poor detection capability for weak bond defects at the root of friction stir welds in 2219 aluminum alloys. Therefore, linear scanning is used for ultrasonic phased array testing of friction stir welds in rocket propellant tanks, a significant difference from other industries.

[0004] Existing technologies have the following drawbacks when inspecting friction stir welds in thick 2219 aluminum alloy tanks:

[0005] (1) Root weak bond and incomplete penetration are common defects in friction stir welds and are also the main targets of ultrasonic phased array testing. Existing testing technology cannot complete the internal quality testing of welds with a thickness of more than 20mm on one side. Supplementary testing is required on the back side. Due to the limitations of the ultrasonic principle itself, there is a blind zone near the probe surface. Therefore, existing technology cannot detect the root weak bond and incomplete penetration defects of friction stir welds in thick 2219 aluminum alloy tanks.

[0006] (2) The maximum thickness that the existing testing technology can detect is 15mm. It cannot complete the internal quality inspection of welds with a thickness of more than 20mm on one side. Supplementary inspection is required on the back side, which results in low testing efficiency and high labor intensity.

[0007] (3) After the existing detection technology is completed, the gain is only verified by the transverse through hole test block, while the energy change of ultrasonic waves in the workpiece space and the ability to detect adjacent defects are not verified.

[0008] (4) Existing detection technologies, after adjusting the gain using artificial defects, can only provide the smallest equivalent defect that can be detected, but cannot provide a quantitative description of the smallest detectable defect, which is not conducive to the implementation of defect elimination work. Summary of the Invention

[0009] In view of this, the present invention aims to propose an ultrasonic phased array testing and calibration method for aluminum alloy welds in rocket propellant tanks. It innovates and optimizes both the design of ultrasonic phased array performance test blocks and process parameters to achieve ultrasonic phased array testing and calibration of friction stir welds in thick 2219 aluminum alloy rocket propellant tanks, thereby solving the above-mentioned problems.

[0010] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0011] A method for ultrasonic phased array testing and calibration of aluminum alloy welds in rocket propellant tanks includes the following steps:

[0012] S1. Start the equipment; connect the probe and control system to the ultrasonic phased array flaw detector, and start the ultrasonic phased array flaw detector and control system;

[0013] S2. Gain Adjustment: Adjust the equipment gain using a test block;

[0014] S3. Energy distribution test: Using test blocks, test whether there is a difference in the reflected wave height of artificial defects in the same group of transverse through holes, and then determine whether there is a difference in the distribution of ultrasonic energy in the horizontal direction and whether there is a wafer fault.

[0015] S4. Detection capability test: Using a test block, the probe is scanned sequentially over artificial defects such as flat-bottomed holes and square grooves to test the quantitative detection capability of the detection process for defects at different burial depths.

[0016] S5. Frontal inspection of weld; defects are assessed through double-sided inspection.

[0017] S6. Detection data storage;

[0018] S7. Gain Verification: Verify the gain using the test timing; the artificial defect waveform height fluctuation should be within 2dB.

[0019] S8. Energy distribution verification: The characteristics of ultrasonic energy distribution are verified using a test block. The fluctuation of artificial defect wave height should be within 2dB.

[0020] S9. Detection capability verification: The detection capability of the detection system is verified using test blocks. The smallest detectable defect size should not be larger than the smallest detectable defect size before product inspection.

[0021] S10, Detection complete.

[0022] Furthermore, the test block includes a gain adjustment test block, an energy distribution test block, and a quantitative detection test block; the gain adjustment test block is used for S2 gain adjustment, the energy distribution test block is used for S3 energy distribution testing, and the quantitative detection block is used for S4 detection capability testing.

[0023] Furthermore, the gain adjustment test block is a cuboid structure with a length-to-width-to-height ratio of 25:4:3; the gain adjustment test block is provided with an artificial defect hole.

[0024] Furthermore, the diameter of the first artificial defect hole is 1mm, and the burial depth of the first artificial defect hole is between 13mm and 27mm; the burial depth is the distance between the first artificial defect hole and the top of the gain adjustment block.

[0025] Furthermore, the energy distribution test block includes a first distribution test block and a second distribution test block. The first distribution test block has a cuboid structure with a length-width-height ratio of 76:5:6. The first distribution test block has second artificial defect holes, which are distributed in groups of four. The second artificial defect holes in each group are arranged horizontally with a spacing of 3 mm, and there are nine groups. The distance between the burial depth of each group of second artificial defect holes and the top of the first distribution test block is between 3 mm and 27 mm. The distance between the first group of second artificial defect holes and the end of the first distribution test block is 2.5 mm, and the spacing between the other groups of second artificial defect holes is 3 mm.

[0026] Furthermore, the second distribution test block has a cuboid structure with a length-width-height ratio of 80:25:28; the second distribution test block is provided with a third artificial defect hole, which is arranged in groups of 5, with the 5 third artificial defect holes in each group arranged horizontally, with a 3.5mm interval between each pair, and a 2.5mm spacing between the third artificial defect holes in each group.

[0027] Furthermore, the quantitative test block has a cuboid structure with a length-to-width-to-height ratio ranging from 300:90:5 to 300:90:25. The surface of the quantitative test block is provided with flat-bottomed holes and square-groove artificial defect holes. The flat-bottomed holes are set in two groups, and the square-groove artificial defect holes are set in one group. Each group of flat-bottomed holes contains 4 flat-bottomed holes, and the center-to-center distance between each pair is 30mm. Each group of square-groove artificial defect holes contains 5 square-groove artificial defect holes, and the center-to-center distance between each pair is 30mm. The distance between the two groups of flat-bottomed holes is 40mm.

[0028] Furthermore, both the flat-bottomed holes and the square-groove artificial defect holes are arranged in a straight line; two sets of parallel flat-bottomed holes are set on one side of the quantitative test block, and the set of square-groove artificial defect holes is set on the other side of the quantitative monitoring test block.

[0029] Furthermore, the first group of flat-bottomed holes are defined as K1, K2, K3, and K4 in sequence; the second group of flat-bottomed holes are defined as K5, K6, K7, and K8 in sequence; and the square groove artificial defect holes are defined as L1, L2, L3, L4, and L5.

[0030] Furthermore, the steps for using the quantitative test block are as follows:

[0031] S1. Scan each defect with the probe in sequence, measure the equivalent size of the defect, and record it.

[0032] S2. If the probe has been working for more than 2 hours or after the test is completed, use the probe again to scan each defect in sequence and compare it with the results of the first test. The measurement values ​​before and after the test should not have a deviation of more than 2dB.

[0033] Compared with existing technologies, the ultrasonic phased array detection and calibration method for aluminum alloy welds in rocket propellant tanks described in this invention has the following advantages:

[0034] This invention, through the design of performance testing blocks and optimization of testing parameters, ultimately achieves ultrasonic phased array testing and calibration of friction stir welds in thick 2219 aluminum alloy rocket propellant tanks. This technology offers the following advantages:

[0035] (1) The thickness range of ultrasonic phased array detection for friction stir welds of 2219 aluminum alloy rocket propellant tanks has been expanded to 27 mm.

[0036] (2) The performance test block can not only quantitatively test the detection performance of the ultrasonic phased array detection system, but also calibrate the energy distribution of ultrasonic waves in the workpiece under inspection, thereby improving the reliability of the detection. Attached Figure Description

[0037] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0038] Figure 1 This is a side view of the gain adjustment test block according to an embodiment of the present invention;

[0039] Figure 2 This is a top view of the gain adjustment test block described in an embodiment of the present invention;

[0040] Figure 3 This is a side view of the No. 1 distribution test block according to an embodiment of the present invention;

[0041] Figure 4 This is a top view of the No. 1 distribution test block according to an embodiment of the present invention;

[0042] Figure 5 This is a side view of the second distribution test block according to an embodiment of the present invention;

[0043] Figure 6 This is a top view of the second distribution test block according to an embodiment of the present invention;

[0044] Figure 7 This is a top view of the quantitative detection test block according to an embodiment of the present invention;

[0045] Figure 8 As described in the embodiments of the present invention Figure 7 Sectional view of plane AA;

[0046] Figure 9 As described in the embodiments of the present invention Figure 7 BB section view;

[0047] Figure 10 As described in the embodiments of the present invention Figure 7 CC section view;

[0048] Figure 11 This is a reference diagram for ultrasonic phased array testing of friction stir welds according to an embodiment of the present invention;

[0049] Figure 12 This is a reference diagram for ultrasonic phased array detection of defects in friction stir welds according to an embodiment of the present invention.

[0050] Explanation of reference numerals in the attached figures:

[0051] 1. Gain adjustment test block; 11. Artificial defect hole No. 1; 21. Distribution test block No. 1; 211. Artificial defect hole No. 2; 22. Distribution test block No. 2; 221. Artificial defect hole No. 3; 3. Quantitative test block; 31. Flat bottom hole; 32. Square groove artificial defect hole. Detailed Implementation

[0052] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0053] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0054] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0055] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0056] This invention is achieved by constructing an ultrasonic phased array inspection system for friction stir welds. The system comprises a probe, an ultrasonic phased array flaw detector, and a control system. Its principle is as follows: the control system adjusts the operating parameters of the ultrasonic phased array probe. The ultrasonic phased array flaw detector transmits digital commands through the probe, which generates ultrasonic waves that are transmitted to the workpiece to inspect its internal quality. When the ultrasonic waves encounter a defect interface or the lower surface of the workpiece, they are reflected and received by the probe, which converts them into digital signals. The probe transmits these digital signals to the ultrasonic phased array flaw detector. After processing by the flaw detector, an image signal is generated and transmitted to the control system. This presents a three-dimensional image of the workpiece's internal information on the control system, allowing inspectors to assess and locate defects.

[0057] A method for ultrasonic phased array testing and calibration of aluminum alloy welds in rocket propellant tanks includes the following steps:

[0058] S1. Start the equipment; connect the probe and control system to the ultrasonic phased array flaw detector, and start the ultrasonic phased array flaw detector and control system;

[0059] S2. Gain Adjustment: Adjust the equipment gain using a test block;

[0060] S3. Energy distribution test: Using test blocks, test whether there is a difference in the reflected wave height of artificial defects in the same group of transverse through holes, and then determine whether there is a difference in the distribution of ultrasonic energy in the horizontal direction and whether there is a wafer fault.

[0061] S4. Detection capability test: Using a test block, the probe is scanned sequentially over the flat-bottomed hole 31 and the square groove for artificial defects to test the quantitative detection capability of the detection process for defects at different burial depths.

[0062] S5. Frontal inspection of weld; defects are assessed through double-sided inspection.

[0063] S6. Detection data storage;

[0064] S7. Gain Verification: Verify the gain using the test timing; the artificial defect waveform height fluctuation should be within 2dB.

[0065] S8. Energy distribution verification: The characteristics of ultrasonic energy distribution are verified using a test block. The fluctuation of artificial defect wave height should be within 2dB.

[0066] S9. Detection capability verification: The detection capability of the detection system is verified using test blocks. The smallest detectable defect size should not be larger than the smallest detectable defect size before product inspection.

[0067] S10, Detection complete.

[0068] Preferably, the test block includes a gain adjustment test block 1, an energy distribution test block, and a quantitative detection test block 3; the gain adjustment test block 1 is used for gain adjustment in S2, the energy distribution test block is used for energy distribution testing in S3, and the quantitative detection test block 3 is used for detection capability testing in S4.

[0069] Preferred, such as Figure 1 Figure 2 As indicated, the gain adjustment test block 1 is a cuboid structure, and the length-width-height ratio of the gain adjustment test block 1 is 25:4:3; specifically, in this embodiment, it is 250mm long, 40mm wide, and 30mm high; the gain adjustment test block 1 is provided with an artificial defect hole 11, which is a horizontal through hole.

[0070] Preferably, the diameter of the first artificial defect hole 11 is 1mm, and the burial depth of the first artificial defect hole 11 is between 13mm and 27mm; the burial depth is the distance between the first artificial defect hole 11 and the top of the gain adjustment block.

[0071] Preferably, the burial depths of the first artificial defect hole 11 are 13 / 15 / 17 / 19 / 21 / 23 / 25 / 27 mm; each burial depth is a test block, and there are a total of 9 types of gain adjustment test blocks 1;

[0072] Preferred, such as Figure 3 Figure 4 As shown, the energy distribution test block includes a first distribution test block 21 and a second distribution test block 22. The first distribution test block 21 has a cuboid structure with a length-width-height ratio of 76:5:6. In this embodiment, it is specifically 380mm long, 25mm wide, and 30mm high. The first distribution test block 21 has a second artificial defect hole 211 with a diameter of 1mm. The second artificial defect holes 211 are distributed in groups of 4, with each group having 4 holes arranged horizontally and spaced 3mm apart. There are 9 groups in total. The distance between the burial depth of each group of second artificial defect holes 211 and the top of the first distribution test block 21 is between 3mm and 27mm. Specifically, the distances between the burial depth of each group of second artificial defect holes 211 and the top of the first distribution test block 21 are 3, 6, 9, 12, 15, 18, 21, 24, and 27mm.

[0073] The distance between the second artificial defect hole 211 in the first group and the end of the first distribution test block 21 is 2.5 mm, and the spacing between the second artificial defect holes 211 in each other group is 3 mm.

[0074] Preferred, such as Figure 5 Figure 6As shown, the second distribution test block 22 has a cuboid structure with a length-width-height ratio of 80:25:28. The second distribution test block 22 has a third artificial defect hole 221 with a diameter of 0.5 mm. The third artificial defect holes 221 are arranged in groups of five, with each group of five holes horizontally spaced 3.5 mm apart. The spacing between any two holes in each group is 2.5 mm. The last group of third artificial defect holes 221 is 3 mm from the bottom. There are a total of 10 rows of third artificial defect holes 221.

[0075] Currently, linear array probes with 64 or 128 wafers are selected, and the number of wafers excited simultaneously (spindle aperture) is 12-24. The purpose of the first distribution test block 21 is as follows: 1. After prolonged use, some wafers may become damaged, requiring detection of wafer faults; 2. To assess the resolution of adjacent defects. The specific operation is as follows: The probe sequentially scans each group of transverse through-holes on the first type of artificial defect test block. The energy display changes when a certain group of wafers passes over the transverse through-holes in the same group, thus identifying the presence of faulty wafers. Simultaneously, it is observed whether the four transverse through-holes in each group can be distinguished, thereby testing the resolution of adjacent defects.

[0076] The second distribution test block 22 is used to detect the energy field distribution in the probe at a certain focusing depth. The specific operation is as follows: place the center of the probe in the center of the test block, adjust different focusing depths, and observe the changes in the energy field in the focusing and non-focusing areas, as well as the energy fluctuations, to verify whether there is a decrease or increase in energy in a certain area during the detection process.

[0077] Preferred, such as Figures 7-10 As shown, the quantitative test block 3 has a cuboid structure with a length-to-width-to-height ratio ranging from 300:90:5 to 300:90:25; it comes in five sizes, with equal length and width, and heights of 5 / 10 / 15 / 20 / 25 mm respectively; the surface of the quantitative test block 3 is provided with flat-bottomed holes 31 and square-groove artificial defect holes 32; the flat-bottomed holes 31 are arranged in two groups, and the square-groove artificial defect holes 32 are arranged in one group. Each group of flat-bottomed holes 31 contains 4 flat-bottomed holes 31, and the center-to-center distance between each pair is 30 mm; each group of square-groove artificial defect holes 32 contains 5 square-groove artificial defect holes 32, and the center-to-center distance between each pair is 30 mm; the distance between the two groups of flat-bottomed holes 31 is 40 mm.

[0078] Preferably, the flat-bottomed holes 31 and the square groove artificial defect holes 32 are arranged in a straight line; two sets of parallel flat-bottomed holes 31 are arranged on one side of the quantitative test block 3, and the set of square groove artificial defect holes 32 is arranged on the other side of the quantitative monitoring block.

[0079] Preferably, the first group of flat-bottomed holes 31 are defined as K1, K2, K3, and K4 in sequence; the second group of flat-bottomed holes 31 are defined as K5, K6, K7, and K8 in sequence; and the square groove artificial defect holes 32 are defined as L1, L2, L3, L4, and L5. Specific parameters are shown in the table below:

[0080]

[0081]

[0082] This test block can quantitatively test the detection capability of artificial defects such as flat-bottomed holes (simulating hole-type defects) and square grooves (simulating cracks and incomplete penetration defects) under different detection parameters. The specific operation is as follows: scan each defect sequentially with the probe, measure the equivalent size of the defect and record it. If the probe works for more than 2 hours or after the test is completed, scan each defect sequentially with the probe again and compare it with the result of the first test. The deviation between the two measurements before and after the test should not exceed 2dB.

[0083] The ultrasonic phased array testing process parameters for friction stir welds in thick 2219 aluminum alloy rocket propellant tanks, as determined by experiments, are shown in the table below:

[0084]

[0085]

[0086] Example: Taking ultrasonic phased array testing of a 19mm thick friction stir weld as an example, the specific steps are as follows:

[0087] (1) Connect the probe and control system to the ultrasonic phased array flaw detector and start the ultrasonic phased array flaw detector and control system;

[0088] (2) Based on the product thickness of 19mm, adjust the incident angle to 17°, the repetition frequency to 6000Hz, the thickness display range to -2~38mm, the focusing depth to 18mm, the scanning speed to 20mm / s, and the spindle aperture to 20. Use the gain adjustment test block 1 to adjust the equipment gain so that the artificial defect wave height reaches 80%, and then increase it by 15dB.

[0089] (3) Select a Φ1mm transverse through-hole energy distribution test block. The probe is used to scan each group of transverse through-hole artificial defects with burial depths of 3, 6, 9, 12, 15, 18, and 21mm in sequence. Test whether there is a difference in the reflected wave height of the artificial defects in the same group of transverse through-holes, and then determine whether there is a difference in the distribution of ultrasonic energy in the horizontal direction and whether there is a wafer fault. At the same time, determine the resolution capability of different detection processes for adjacent defects at different depths. Select a Φ0.5mm transverse through-hole energy distribution test block. Place the probe in the middle of the artificial defect array and observe the difference in the reflected waves of each artificial defect, and then determine the change of the energy field in the focused area and the non-focused area.

[0090] (4) Select quantitative test blocks 3 with thicknesses of 5, 10, 15, and 20 mm. The probe scans the flat-bottomed hole 31 and the square groove artificial defects in sequence to test the quantitative detection capability of the detection process for defects at different burial depths.

[0091] (5) Select probe positions 1 and 2 on the front side of the weld for double-sided scanning and assess defects; such as Figure 11 , Figure 12 As shown, unlike the commonly used sector scanning detection at present, this application uses linear scanning to achieve better results;

[0092] (6) Store the detection data;

[0093] (7) Use gain adjustment test block 1 to verify the gain. The artificial defect wave height fluctuation should be within 2dB.

[0094] (8) Use the ultrasonic energy distribution characteristic test block to verify the ultrasonic energy distribution characteristics. The artificial defect wave height fluctuation should be within 2dB.

[0095] (9) The detection capability of the detection system is verified by using a quantitative test block for ultrasonic phased array detection capability. The smallest detectable defect size should not be larger than the smallest detectable defect size before product testing.

[0096] (10) The test is over.

[0097] Definitions:

[0098] (1) Friction stir welding: After the high-speed rotating stirring head is inserted into the workpiece, it moves along the welding direction. Frictional heat is generated at the contact point between the stirring head and the workpiece, causing the attached metal profile to plastically soften. The softened layer fills the cavity formed behind the stirring needle under the action of the rotating stirring head, and the material connection is achieved under the stirring and squeezing action of the shoulder and the stirring needle.

[0099] (2) Voids: Defects such as worm-like or tunnel-like shapes formed inside the weld seam of friction stir welding along the welding direction;

[0100] (3) Weak bond at the root: A welding defect in which the joined materials are in close contact but fail to form an effective bond in the plastic deformation zone at the root of the weld.

[0101] (4) Linear scanning: Each group of element beams of the phased array probe takes turns to perform linear scanning, and the scanning angle and focal length remain constant, also known as E-scan.

[0102] (5) Sector scanning: The phased array probe element beam continuously performs sector scanning at a certain step angle, also known as S-scan;

[0103] (6) Decibels (dB): 20 times the logarithm of the ratio of the amplitudes of two ultrasound signals to the base 10;

[0104] (7) Near field: The region in which the sound pressure does not change monotonically with distance due to interference;

[0105] (8) Burial depth: The distance between the artificial defect and the workpiece surface;

[0106] (9) Artificial defects: By mechanically processing different shapes and sizes of flat-bottomed holes, horizontal through holes, square grooves and other structures on the test block, different types of natural defects are simulated.

[0107] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for ultrasonic phased array testing and calibration of aluminum alloy welds in rocket propellant tanks, characterized in that: Includes the following steps: S1. Start the equipment; connect the probe and control system to the ultrasonic phased array flaw detector, and start the ultrasonic phased array flaw detector and control system; the ultrasonic phased array testing method uses linear scanning, and the linear scanning testing parameters are set as follows: scanning speed control 10~30mm / s, spindle aperture: 12~24, gain adjustment to Φ1-9dB; when the weld thickness is 17mm, the display range is -2~34mm, the repetition frequency is 4000~6000Hz, the incident angle is 13~25°, and the focusing depth is 16mm; when the weld thickness is 19mm, the display range is -2~38mm, the repetition frequency is 4000~6000Hz, the incident angle is 13~25°, and the focusing depth is 18mm; when the weld thickness is 2... When the weld thickness is 1mm, the display range is -2 to 42mm, the repetition frequency is 3000 to 5000Hz, the incident angle is 15 to 27°, and the focusing depth is 20mm; when the weld thickness is 23mm, the display range is -2 to 46mm, the repetition frequency is 3000 to 5000Hz, the incident angle is 17 to 29°, and the focusing depth is 22mm; when the weld thickness is 25mm, the display range is -2 to 50mm, the repetition frequency is 3000 to 5000Hz, the incident angle is 17 to 29°, and the focusing depth is 24mm; when the weld thickness is 27mm, the display range is -2 to 54mm, the repetition frequency is 3000 to 5000Hz, the incident angle is 17 to 29°, and the focusing depth is 26mm. S2. Gain Adjustment: Adjust the equipment gain using a test block; S3. Energy distribution test: Using test blocks, test whether there is a difference in the reflected wave height of artificial defects in the same group of transverse through holes, and then determine whether there is a difference in the distribution of ultrasonic energy in the horizontal direction and whether there is a wafer fault. S4. Detection capability test: Using a test block, the probe is scanned sequentially over artificial defects such as flat-bottomed holes and square grooves to test the quantitative detection capability of the detection process for defects at different burial depths. S5. Frontal inspection of weld; defects are assessed through double-sided inspection. S6. Detection data storage; S7. Gain verification: Verify the gain using a test block. The fluctuation of the artificial defect wave height should be within 2dB. S8. Energy distribution verification: The characteristics of ultrasonic energy distribution are verified using a test block. The fluctuation of artificial defect wave height should be within 2dB. S9. Detection capability verification: The detection capability of the detection system is verified using test blocks. The smallest detectable defect size should not be larger than the smallest detectable defect size before product inspection. S10, Detection complete; The test block includes a gain adjustment test block, an energy distribution test block, and a quantitative detection test block; the gain adjustment test block is used for S2 gain adjustment, the energy distribution test block is used for S3 energy distribution testing, and the quantitative detection block is used for S4 detection capability testing. The energy distribution test block includes a first distribution test block and a second distribution test block. The first distribution test block has a cuboid structure with a length-width-height ratio of 76:5:

6. The first distribution test block contains second artificial defect holes, which are arranged in groups of four. Within each group, the second artificial defect holes are horizontally arranged with a spacing of 3 mm, and there are nine groups in total. The distance between the burial depth of each group of second artificial defect holes and the top of the first distribution test block is between 3 mm and 27 mm. The distance between the first artificial defect hole and the end of the first distribution test block is 2.5 mm, and the spacing between the second artificial defect holes in each other group is 3 mm. The second distribution test block has a cuboid structure with a length-width-height ratio of 80:25:

28. The second distribution test block is provided with a third artificial defect hole, which is arranged in groups of 5. The 5 third artificial defect holes in each group are arranged horizontally with a 3.5 mm interval between each pair, and the spacing between the third artificial defect holes in each group is 2.5 mm.

2. The method for ultrasonic phased array detection and calibration of aluminum alloy weld seams in rocket propellant tanks according to claim 1, characterized in that: The gain adjustment test block is a cuboid structure with a length-to-width-to-height ratio of 25:4:

3. The gain adjustment test block contains a first artificial defect hole with a diameter of 1 mm and a depth between 13 mm and 27 mm. The depth is the distance between the first artificial defect hole and the top of the gain adjustment test block.

3. The method for ultrasonic phased array detection and calibration of aluminum alloy welds in rocket propellant tanks according to claim 1, characterized in that: The quantitative test block has a cuboid structure with a length-to-width-to-height ratio ranging from 300:90:5 to 300:90:

25. The surface of the quantitative test block is provided with flat-bottomed holes and square-groove artificial defect holes. The flat-bottomed holes are set in two groups, and the square-groove artificial defect holes are set in one group. Each group of flat-bottomed holes contains 4 holes, and the center-to-center distance between each pair is 30mm. Each group of square-groove artificial defect holes contains 5 holes, and the center-to-center distance between each pair is 30mm. The distance between the two groups of flat-bottomed holes is 40mm.

4. The method for ultrasonic phased array detection and calibration of aluminum alloy weld seams in rocket propellant tanks according to claim 3, characterized in that: Both the flat-bottomed holes and the square-groove artificial defect holes are arranged in a straight line; two sets of parallel flat-bottomed holes are set on one side of the quantitative test block, and the set of square-groove artificial defect holes is set on the other side of the quantitative test block.

5. The method for ultrasonic phased array detection and calibration of aluminum alloy weld seams in rocket propellant tanks according to claim 3, characterized in that: The first group of flat-bottomed holes are defined as K1, K2, K3, and K4 in sequence; the second group of flat-bottomed holes are defined as K5, K6, K7, and K8 in sequence; and the square groove artificial defect holes are defined as L1, L2, L3, L4, and L5.

6. The method for ultrasonic phased array detection and calibration of aluminum alloy weld seams in rocket propellant tanks according to claim 5, characterized in that, The steps for using the quantitative test block are as follows: S1. Scan each defect with the probe in sequence, measure the equivalent size of the defect, and record it. S2. If the probe has been working for more than 2 hours or after the test is completed, use the probe again to scan each defect in sequence and compare it with the results of the first test. The measurement values ​​before and after the test should not have a deviation of more than 2dB.

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