B-type sleeve detection method based on double-probe phased array full-focusing acoustic projection

Abstract

The invention relates to a B-type sleeve detection method based on double-probe phased array full-focusing acoustic projection. The B-type sleeve detection method comprises the following specific steps: S1, collecting a signal of a special reference block; s2, collecting a signal of a test block to be detected; s3, subtracting the signal of the to-be-detected test block from the signal of the special reference block, wherein the subtracted signal only contains feature information related to the defect of the to-be-detected test block; and S4, performing full-focusing imaging on the signal in the S3 to obtain the defect morphology and size of the test block to be detected. The method has the beneficial effects that the double probes are used for detection, the defect morphology in the to-be-detected welding seam area can be clearly displayed, accurate qualitative and quantitative analysis is carried out, the detection is more comprehensive, and the accuracy is high.

Description

Technical Field

[0001] The invention relates to the technical field of nondestructive testing, and in particular to a B-type sleeve testing method based on dual-probe phased array fully focused acoustic projection. Background Art

[0002] The B-type sleeve is one of the common technologies used for pipeline repair. It uses two tile-shaped steel pipes of the same material and specifications, butt-welded to the outside of the mother pipe to be repaired, and then overlapped with the mother pipe at both ends through fillet welds to form a fully enclosed sleeve to reinforce the problem of reduced pressure strength caused by defects in the pipe wall. However, both butt welds and fillet welds are prone to welding defects, especially the horizontal fusion zone of the fillet weld. Defects close to the horizontal direction are very difficult to detect. For the detection of such fillet welds, it is generally recommended to use the traditional ultrasonic phased array method, that is, using a phased array probe to perform fan-scan imaging of the defective part through the focusing law of delayed excitation of the array element. The detection method of fully focused imaging using a single phased linear array probe has not yet been applied to the fillet welds of the B-type sleeve.

[0003] Limited by the special structure of the B-type sleeve, the traditional phased array detection usually places the probe on the sleeve or the mother tube, and uses primary or secondary waves for detection. At this time, for horizontal strip defects in the horizontal fusion line area of ​​the diagonal weld or with a small angle to the horizontal direction, the probe often finds it difficult to capture the mirror reflection of the defect, and the defect image can only show one or two end corners of the defect. Two artificial horizontal grooves with a length of 8mm and a width of 0.6mm only show four endpoints in the ultrasonic phased array fan scan image, and the results of full focus imaging are similar to fan scans. At this time, it is impossible to determine from the defect image whether the defects are four point defects or two groove defects, that is, the defect image cannot truly and correctly reflect the defects, which is easy to cause misjudgment. Summary of the invention

[0004] The invention provides a B-type sleeve detection method based on dual-probe phased array fully focused acoustic projection, aiming to solve the problems in the prior art.

[0005] The technical solution of the present invention to solve the above technical problems is as follows:

[0006] A B-type sleeve detection method based on dual-probe phased array fully focused acoustic projection includes the following specific steps:

[0007] S1: Collect the signal of the special comparison test block;

[0008] S2: Collect the signal of the test block to be tested;

[0009] S3: Subtract the signal of the test block to be inspected from the signal of the special comparison test block, and the signal after the subtraction only contains characteristic information related to the defects of the test block to be inspected;

[0010] S4: Perform full-focus imaging on the signal in S3 to obtain the defect morphology and size of the test block to be inspected.

[0011] The beneficial effects of the present invention are as follows: during the detection process, S1: collecting the signal of a special comparison test block; S2: collecting the signal of the test block to be detected; S3: subtracting the signal of the test block to be detected from the signal of the special comparison test block, and the signal after the subtraction only contains characteristic information related to the defects of the test block to be detected; S4: performing full-focus imaging on the signal in S3 to obtain the defect morphology and size of the test block to be detected.

[0012] The present invention utilizes dual-probe detection, which can clearly display the defect morphology in the weld area to be tested, and perform accurate qualitative and quantitative analysis, so that the detection is more comprehensive and highly accurate.

[0013] Based on the above technical solution, the present invention can also be improved as follows.

[0014] Further, the S4 specifically includes:

[0015] S41: performing Hilbert transform on the obtained signal;

[0016] S42: Select the area to be imaged so that the area to be imaged should cover the fillet weld area of ​​the entire sleeve and the mother tube. After calculating the amplitudes of all pixel points, the defect outline and information will be presented on the bottom surface of the mother tube in the imaging image.

[0017] The beneficial effect of adopting the above further scheme is to perform Hilbert transform on the obtained signal, that is, to envelop the signal, and the imaging effect is better; at the same time, after calculating the amplitude of all pixel points in the imaging area, the defect outline and information will be presented at the bottom surface of the mother tube in the imaging image.

[0018] Further, the S4 also includes S43:

[0019] Since the location where the defect appears after imaging is not the location of the defect itself, the end point of the defect should be found in combination with the results shown in the traditional full-focus spontaneous emission and self-reception mode or PAUT, and the dual-probe imaging results should be combined with the latter to reversely infer the defect morphology and size.

[0020] The beneficial effect of adopting the above further solution is that the method can be used to find the end point of the defect of the mother tube to be tested, and the dual-probe imaging result is combined with the latter to reversely infer the defect morphology and size.

[0021] Further, the S42 specifically includes:

[0022] S421: Taking the first transmitting array element as the starting point, selecting the area to be imaged so that the area to be imaged should cover the fillet weld area of ​​the entire sleeve and the mother tube;

[0023] S422: Select the first pixel point, calculate the distance and acoustic time from each transmitting array element and receiving array element to the pixel point, index the corresponding amplitude from the collected signal, and perform superposition;

[0024] S423: Repeat the operation of S422 for all pixels;

[0025] S424: After calculating the amplitudes of all pixel points, the defect outline and information will be presented at the bottom surface of the mother tube in the imaging image.

[0026] The beneficial effect of adopting the above further solution is that the method is simple, and after calculating the amplitudes of all pixel points, the defect outline and information will be presented at the bottom surface of the mother tube in the imaging image.

[0027] Further, the S2 specifically includes:

[0028] Place two linear array probes containing N array elements on the sleeve and the mother pipe to be tested respectively, and keep the array element directions of the two linear array probes consistent. At the same time, record the distances between the centers of the No. 1 array elements of the two linear array probes in the x direction and the z direction respectively.

[0029] The beneficial effect of adopting the above further solution is that the method is simple and the distance between the centers of the No. 1 array elements of the two linear array probes in the x-direction and the z-direction can be obtained. The data is used for the subsequent acoustic time calculation in the full-focus imaging.

[0030] Further, the S1 specifically includes:

[0031] Place two linear array probes containing N array elements on the comparison sleeve and the comparison mother tube respectively, and keep the array element directions of the two linear array probes consistent. At the same time, record the distances between the centers of the No. 1 array elements of the two linear array probes in the x and z directions respectively.

[0032] The beneficial effect of adopting the above further solution is that the method is simple and the distance between the centers of the No. 1 array elements of the two linear array probes in the x-direction and the z-direction can be obtained. The data is used for the subsequent acoustic time calculation in the full-focus imaging.

[0033] Further, all parameters of the comparison sleeve fillet weld in S1 are consistent with those of the sleeve fillet weld to be tested in S2, and the comparison sleeve fillet weld has no defects.

[0034] The beneficial effects of adopting the above further scheme are that the method is simple, the setting is reasonable, and it is convenient for subsequent calculations with high accuracy.

[0035] Furthermore, the two linear array probes in S1 and S2 are respectively one-dimensional linear array probes.

[0036] The beneficial effect of adopting the above further scheme is that the one-dimensional linear array probe is reasonably adopted, and its advantages mainly include high-speed signal acquisition, high resolution and high precision, high-speed imaging and low noise level.

[0037] Furthermore, the two linear array probes in S1 and S2 respectively include the same number of array elements.

[0038] The beneficial effect of adopting the above further solution is that the number of array elements included in the two linear array probes is reasonably set with high accuracy.

[0039] Furthermore, the two linear array probes in S1 and S2 respectively include 16 array elements.

[0040] The beneficial effect of adopting the above further solution is that the number of array elements included in the two linear array probes is reasonably set with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a detection flow chart of the present invention;

[0042] Figure 2 It is an assembly diagram of two linear array probes, a sleeve and a mother tube in the present invention;

[0043] Figure 3 Schematic diagram of the time domain reference signal collected by the dual probes in the present invention;

[0044] Figure 4 It is a schematic diagram of the signal collected by the dual probes in the present invention when the time domain contains strip defects;

[0045] Figure 5 It is a structural schematic diagram of a comparative test block in the present invention;

[0046] Figure 6 It is a structural schematic diagram of a case 1 of the present invention in which a horizontal groove defect exists in the test block to be inspected;

[0047] Figure 7 This is a schematic diagram of the structure when the test block to be inspected has two circular hole defects in implementation example 1 of the present invention;

[0048] Figure 8 This is a half-span full-focus imaging image of a groove defect in the test block to be inspected in Example 1 of the present invention;

[0049] Fig. 9 This is a half-span full-focus imaging image of two circular hole defects in the test block to be inspected in Example 1 of the present invention;

[0050] Fig.10 This is a single probe fully focused imaging image of the groove defect of the test block to be inspected in Example 1 of the present invention;

[0051] Fig.11 It is a structural schematic diagram of a test block to be inspected in Example 2 of the present invention when there is a horizontal double groove defect;

[0052] Fig.12 It is a structural schematic diagram of the test block to be inspected when there are four circular hole defects in implementation case 2 of the present invention;

[0053] Fig.13 This is a half-span full focus imaging image of two groove defects in the test block to be inspected in Example 2 of the present invention;

[0054] Fig.14 This is a half-span fully focused imaging image of four circular hole defects in the test block to be inspected in implementation example 2 of the present invention.

[0055] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0056] 1. Linear array probe; 2. Sleeve; 3. Mother tube. DETAILED DESCRIPTION

[0057] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0058] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0059] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0060] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0061] Example 1

[0062] like Figures 1 to 14 As shown, this embodiment provides a B-type sleeve detection method based on dual-probe phased array fully focused acoustic projection, including the following specific steps:

[0063] S1: Collect the signal of the special comparison test block;

[0064] S2: Collect the signal of the test block to be tested;

[0065] S3: Subtract the signal of the test block to be inspected from the signal of the special comparison test block, and the signal after the subtraction only contains characteristic information related to the defects of the test block to be inspected;

[0066] S4: Perform full-focus imaging on the signal in S3 to obtain the defect morphology and size of the test block to be inspected.

[0067] During the detection process, S1: collect the signal of the special comparison test block; S2: collect the signal of the test block to be detected; S3: subtract the signal of the test block to be detected from the signal of the special comparison test block, and the signal after the subtraction only contains characteristic information related to the defects of the test block to be detected; S4: perform full-focus imaging on the signal in S3 to obtain the defect morphology and size of the test block to be detected.

[0068] This embodiment utilizes dual-probe detection, which can clearly display the defect morphology in the weld area to be tested, and perform accurate qualitative and quantitative analysis, so that the detection is more comprehensive and highly accurate.

[0069] Example 2

[0070] On the basis of Example 1, in this embodiment, S4 specifically includes:

[0071] S41: performing Hilbert transform on the obtained signal;

[0072] S42: Select the area to be imaged so that the area to be imaged should cover the fillet weld area of ​​the entire sleeve and the mother tube. After calculating the amplitudes of all pixel points, the defect outline and information will be presented on the bottom surface of the mother tube in the imaging image.

[0073] The obtained signal is subjected to Hilbert transform, that is, the signal is enveloped, and the imaging effect is better; at the same time, after calculating the amplitude of all pixel points in the imaging area, the defect outline and information will be presented at the bottom surface of the mother tube in the imaging image.

[0074] Example 3

[0075] On the basis of Example 2, in this embodiment, S4 further includes S43:

[0076] Since the location where the defect appears after imaging is not the location of the defect itself, the end point of the defect should be found in combination with the results shown in the traditional full-focus spontaneous emission and self-reception mode or PAUT, and the dual-probe imaging results should be combined with the latter to reversely infer the defect morphology and size.

[0077] This method can be used to find the end point of the mother tube defect to be tested, and the dual-probe imaging results can be combined with the latter to infer the defect morphology and size.

[0078] Example 4

[0079] On the basis of any one of Embodiments 2 to 3, in this embodiment, S42 specifically includes:

[0080] S421: Taking the first transmitting array element as the starting point, selecting the area to be imaged, so that the area to be imaged should cover the fillet weld area of ​​the entire sleeve 2 and the mother tube 3;

[0081] S422: Select the first pixel point, calculate the distance and acoustic time from each transmitting array element and receiving array element to the pixel point, index the corresponding amplitude from the collected signal, and perform superposition;

[0082] S423: Repeat the operation of S422 for all pixels;

[0083] S424: After calculating the amplitudes of all pixel points, the defect outline and information will be presented at the bottom surface of the mother tube in the imaging image.

[0084] The method is simple. After calculating the amplitude of all pixel points, the defect outline and information will be presented at the bottom surface of the mother tube in the imaging image.

[0085] Example 5

[0086] On the basis of the above embodiments, in this embodiment, S2 specifically includes:

[0087] Two linear array probes 1 containing N array elements are placed on the sleeve and the mother pipe to be tested respectively, and the array element directions of the two linear array probes 1 are kept consistent. At the same time, the distances between the centers of the No. 1 array elements of the two linear array probes 1 in the x direction and the z direction are recorded respectively.

[0088] The method is simple and can obtain the distance between the centers of the No. 1 array elements of the two linear array probes in the x-direction and the z-direction. The data is used for the subsequent acoustic time calculation in the full-focus imaging.

[0089] Example 6

[0090] On the basis of the above embodiments, in this embodiment, S1 specifically includes:

[0091] Place two linear array probes containing N array elements on the comparison sleeve and the comparison mother tube respectively, and keep the array element directions of the two linear array probes consistent. At the same time, record the distances between the centers of the No. 1 array elements of the two linear array probes in the x and z directions respectively.

[0092] The method is simple and can obtain the distance between the centers of the No. 1 array elements of the two linear array probes in the x-direction and the z-direction. The data is used for the subsequent acoustic time calculation in the full-focus imaging.

[0093] Example 7

[0094] On the basis of Example 6, in this example, all parameters of the comparison sleeve fillet weld in S1 are consistent with those of the sleeve fillet weld to be tested in S2, and the comparison sleeve fillet weld has no defects.

[0095] The method is simple and has reasonable settings to facilitate subsequent calculations with high accuracy.

[0096] Example 8

[0097] On the basis of any one of Embodiment 5 or Embodiment 6, in this embodiment, the two linear array probes in S1 and S2 are respectively one-dimensional linear array probes.

[0098] The one-dimensional linear array probe is used reasonably, and its advantages mainly include high-speed signal acquisition, high resolution and high precision, high-speed imaging and low noise level.

[0099] Example 9

[0100] On the basis of any one of Embodiment 5 or Embodiment 6, in this embodiment, the two linear array probes in S1 and S2 respectively include the same number of array elements.

[0101] The number of array elements contained in the two linear array probes is reasonably set and has high accuracy.

[0102] Example 10

[0103] On the basis of Example 9, in this embodiment, the two linear array probes in S1 and S2 respectively include 16 array elements.

[0104] The number of array elements contained in the two linear array probes is reasonably set and has high accuracy.

[0105] Based on the above solution, the number of array elements included in each linear array probe is generally 8, 16, 32, 64 or 128. This embodiment adopts 16 array elements.

[0106] The specific steps of the B-type sleeve detection method provided by the present invention are as follows:

[0107] 1) First collect the signal of the special comparison test block. The definition of the special comparison test block is: a sample with the same material and specifications as the test block to be inspected but without defects inside. In the actual pipeline inspection process, you can first use the traditional full focusing method or PAUT fan scanning to circle the pipeline to find the part without defects, record the current position and place the dual probe system for signal acquisition. This signal is the signal of the special comparison test block;

[0108] 2) Place two linear array probes with N array elements on the sleeve and the mother tube respectively. The placement position should be as close to the weld area as possible, and the array element directions of the two linear array probes should be kept consistent. For example, the No. 1 array element is on the left. The placement process requires a double probe fixing bracket to ensure that the two probes are aligned in the y direction and can be well coupled with the sleeve and the mother tube respectively;

[0109] 3) Record the distances between the centers of the first array elements of the two linear array probes in the x-direction and the z-direction respectively. This data is used for the subsequent acoustic time calculation in the full-focus imaging.

[0110] 4) Collecting signals from the detected part according to the method shown in step 2;

[0111] 5) Subtract the model signal of the test block to be inspected from the signal of the special comparison test block, and the signal after subtraction only contains the characteristic information related to the defect;

[0112] 6) Performing Hilbert transform on the signal obtained in step 5;

[0113] 7) Taking the No. 1 transmitting array element as the starting point, select the area to be imaged, which should cover the entire fillet weld area;

[0114] 8) Divide the area to be imaged into multiple pixels. The number of pixels determines the accuracy of imaging. The more pixels there are, the higher the imaging accuracy.

[0115] 9) Select the first pixel, calculate the distance and acoustic time from each transmitting array element and receiving array element to the pixel, index the corresponding amplitude from the collected signal, and superimpose them;

[0116] 10) Repeat step 9 for all pixels;

[0117] 11) After calculating the amplitude of all pixels, the defect outline and information will be presented on the bottom surface of the mother tube in the imaging image, which is positively correlated with the projection of the defect in the horizontal direction;

[0118] 12) Since the location where the defect appears after imaging is not the location of the defect itself, the end point of the defect should be found in combination with the results shown in the traditional full-focus spontaneous emission and self-reception mode or PAUT, and the dual-probe imaging results should be combined with the latter to reversely infer the defect morphology and size.

[0119] Two one-dimensional linear array probes are used to detect the defects inside the B-type sleeve fillet weld with sleeve thickness T1, mother tube thickness T2, and gap thickness G, especially for the strip defects close to the horizontal direction that cannot be accurately detected by the traditional phased array detection method. The specific detection principle is:

[0120] Taking the probe emission on the sleeve and the probe reception on the mother tube as an example, each array element of the one-dimensional linear array probe will emit sound waves. The propagation path of the sound waves in the B sleeve is as follows: the sound waves diffuse and propagate after entering the sleeve, first passing through the fillet weld area, and then propagating from the weld area to the bottom surface of the mother tube for reflection. According to Snell's law, part of the reflected echo will propagate to the receiving probe (see Figure 2 If there is a strip defect inside the fillet weld, it will cause a certain shielding of the sound wave. This shielding effect will cause the signal amplitude to change, which can be seen by superimposing all the signals (see Figure 3 and Figure 4 ), and the echo signal will carry defect information. If the above sound propagation path is simplified to Figure 2 The three-stage process shown in the figure can be represented by the half-span mode in the full-focus imaging method. Assuming that the number of array elements in each linear array probe is N, and each array element transmits and receives, a total of N 2 After superimposing all the signals, the morphology of the defect can be presented.

[0121] For the B-type sleeve structure, the present invention designs an imaging algorithm of a half-span full-focus mode of a dual-probe phased array, which can solve the problem that conventional detection means cannot intuitively detect the horizontal defect morphology. The method uses dual probes for signal acquisition and imaging, but is not limited to only one probe transmitting and the other probe receiving. Instead, each probe can both transmit and receive sound waves. Take the use of two probes A and B as an example: there are four modes: A transmits and A receives, A transmits and B receives, B transmits and A receives, and B transmits and B receives. Among them, A transmits and A receives and B transmits and B receives belong to the spontaneous transmission and self-reception mode, which is equivalent to the conventional full-focus acquisition method. The imaging results can respectively reflect the partial morphology of the defect, such as the end angle of the groove; while A transmits and B receives and B transmits and A receives belong to the dual-probe one-transmission and one-reception mode proposed in this patent. Compared with the spontaneous transmission and self-reception mode, it is suitable for detecting strip defects with a near-horizontal direction located in the horizontal fusion line area, which can make up for the deficiency that spontaneous transmission and self-reception cannot receive the mirror reflection echo of the strip defect and cannot fully reflect the defect morphology. After the views of the four modes are superimposed, the morphology of the defect can be fully reflected.

[0122] The more probe array elements there are and the more divided pixel points there are, the better the imaging effect of defects will be. And the positions of the two probes can be adjusted continuously for imaging to find the position with the best defect detection effect.

[0123] The B-type sleeve detection method provided by the present invention has the following advantages:

[0124] 1) For horizontal strip defects, conventional ultrasonic detection technology can only detect the end angles of the defects, which can easily lead to misjudgment of the defects. The method described in this patent can fully detect the overall picture of the strip defects and achieve accurate qualitative and quantitative determination.

[0125] 2) This method has strong interpretability, low operating difficulty, short time consumption, wide application range, and can be adapted to various specifications of B-type sleeves.

[0126] 3) The imaging results of this method are intuitive and can be integrated into the detection software as a supplementary method for traditional phased array detection.

[0127] In order to prove whether the method described in the present invention can distinguish two types of defects that are easily confused by conventional detection methods (i.e. horizontal strip defects and multiple hole defects in the horizontal fusion line area, and the positions of the hole defects are just located at the two end corners of the strip defects), the corresponding B-type sleeve simulation model is established by finite element software, and the method described in the patent is used to detect it. The specific situation is as follows:

[0128] Implementation Case 1:

[0129] Three B-type sleeve simulation model test blocks were established using finite element software. The sleeve specifications are unified as follows: sleeve thickness T1 = 20mm, mother tube thickness T2 = 13mm, gap thickness G = 2mm. Test block 1 is a special comparison test block ( Figure 5 ), and test piece 2 has a horizontal notch defect in the horizontal fusion zone of the fillet weld ( Figure 6 , notch length 8mm, notch width 0.6mm), specimen 3 has two circular hole-shaped defects in the horizontal fusion zone of the fillet weld ( Figure 7 , the radius of the circular hole is 1mm). The defect is detected by the method of top transmission and bottom reception (the transmitting probe is located on the sleeve and the receiving probe is located on the mother tube).

[0130] The specific implementation steps are:

[0131] 1) Place the 16-element transmitting probe on the sleeve and the 16-element receiving probe on the mother tube, and apply a 5MHz excitation signal to each element. The element spacing is 1mm, and the placement position is close to the weld area. Keep the No. 1 element of the two linear array probes on the left;

[0132] 2) Record the distances between the centers of the No. 1 array elements of the two linear array probes in the x-direction and the z-direction, which are 37 mm and 20 mm respectively. This data is used for the subsequent acoustic time calculation in the full-focus imaging.

[0133] 3) First collect the signal of test block 1 according to the method shown in step 1;

[0134] 4) Collect the signals of test block 2 and test block 3 respectively according to the method shown in step 1;

[0135] 5) Subtract the signals of test block 2 and test block 3 from the signal of test block 1. At this time, the signals after subtraction only contain characteristic information related to the defect;

[0136] 6) Performing Hilbert transform on the signal obtained in step 5;

[0137] 7) Taking the No. 1 transmitting array element as the starting point, the area to be imaged is selected to be 54 mm in the x direction and 46 mm in the z direction, and the entire fillet weld area is covered in the area to be imaged;

[0138] 8) Divide the area to be imaged into a plurality of pixels, the number of which is 540*460;

[0139] 9) Select the first pixel, calculate the distance and acoustic time from each transmitting array element and receiving array element to the pixel, index the corresponding amplitude from the collected signal, and superimpose them;

[0140] 10) Repeat step 9 for all pixels;

[0141] 11) After calculating the amplitude of all pixels, the defect outline and information (in the red dotted box) will appear on the bottom surface of the mother tube in the imaging image, which is positively correlated with the projection of the defect in the horizontal direction;

[0142] 12) Since the location where the defect appears after imaging is not the location of the defect itself, the end point of the defect should be found in combination with the results shown in the traditional full-focus spontaneous emission and self-reception mode or PAUT, and the dual-probe imaging results should be combined with the latter to reversely infer the defect morphology and size.

[0143] In order to analyze the parts of the B-type sleeve corresponding to the points with higher amplitude in the imaging image, the imaging results are combined with the contour of the B-type sleeve. The imaging results are shown in Figure 8 and Fig. 9 shown.

[0144] In the dual-probe full-focus image, the projection result of the defect on the bottom surface of the mother tube can clearly distinguish the two types of defects. The defect length measured by the -6dB method is 8.2mm. Compared with the actual length of 8mm, the absolute error is only 0.2mm, which proves that this method has good quantitative ability for horizontal strip defects.

[0145] The dual-probe imaging results are compared with the traditional single-probe full-focus results ( Fig.10 is the single-probe full-focus imaging result). It can be seen that the single-probe full-focus method can still only detect two endpoints, but the dual-probe imaging result just makes up for the end face of the groove. The combination of the two can accurately characterize the morphology and size information of the groove defect.

[0146] Implementation Case 2:

[0147] Three B-type sleeve simulation model test blocks were established using finite element software. The sleeve specifications are unified as follows: sleeve thickness T1 = 23mm, mother tube thickness T2 = 15mm, gap thickness G = 2mm. Test block 1 is a special comparison test block ( Figure 5 ), there are two consistent horizontal notch defects in the horizontal fusion zone of the fillet weld of specimen 2 ( Fig.11 , notch length 7mm, notch width 0.6mm), test piece 3 has four consistent circular hole defects distributed in the horizontal fusion zone of the fillet weld ( Fig.12 The radius of the circular hole is 1mm). The defect is detected by the method of sending down and receiving up (the transmitting probe is located on the mother tube and the receiving probe is located on the sleeve).

[0148] The specific implementation steps are:

[0149] 1) Place the 16-element transmitting probe on the mother tube and the 16-element receiving probe on the sleeve, and apply a 5MHz excitation signal to each element. The element spacing is 1mm, and the placement position is close to the weld area. Keep the No. 1 element of the two linear array probes on the left;

[0150] 2) Record the distances between the centers of the first array elements of the two linear array probes in the x-direction and the z-direction, which are 40 mm and 23 mm respectively. This data is used for the subsequent acoustic time calculation in the full-focus imaging.

[0151] 3) First collect the signal of test block 1 according to the method shown in step 1;

[0152] 4) Collect the signals of test block 2 and test block 3 respectively according to the method shown in step 1;

[0153] 5) Subtract the signals of test block 2 and test block 3 from the signal of test block 1. At this time, the signals after subtraction only contain characteristic information related to the defect;

[0154] 6) Performing Hilbert transform on the signal obtained in step 5;

[0155] 7) Taking the No. 1 transmitting array element as the starting point, the area to be imaged is selected to be 56 mm in the x direction and 53 mm in the z direction, and the entire fillet weld area is covered in the area to be imaged;

[0156] 8) Divide the area to be imaged into a plurality of pixels, the number of which is 560*530;

[0157] 9) Select the first pixel, calculate the distance and acoustic time from each transmitting array element and receiving array element to the pixel, index the corresponding amplitude from the collected signal, and superimpose them;

[0158] 10) Repeat step 9 for all pixels;

[0159] 11) After calculating the amplitude of all pixels, the defect outline and information will be presented at the bottom of the mother tube (in the red dotted box) in the imaging image, which is positively correlated with the projection of the defect in the horizontal direction;

[0160] 12) Since the location where the defect appears after imaging is not the location of the defect itself, the end point of the defect should be found in combination with the results shown in the traditional full-focus spontaneous emission and self-reception mode or PAUT, and the dual-probe imaging results should be combined with the latter to reversely infer the defect morphology and size.

[0161] In order to analyze the parts of the B-type sleeve corresponding to the points with higher amplitude in the imaging image, the imaging results are combined with the contour of the B-type sleeve. The imaging results are shown in Fig.13 and Fig.14 shown.

[0162] In the dual-probe full-focus image, the projections of the two types of defects on the bottom surface of the mother tube show significant differences: the projection amplitude of the two groove defect models is higher, while the projection amplitude of the four circular hole defect models is lower. In addition, the imaging effect of the upper emission and lower collection mode is better than that of the lower emission and upper collection mode.

[0163] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0164] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

[0165] 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 principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A B-type sleeve detection method based on dual-probe phased array fully focused acoustic projection, characterized in that: The specific steps include: S1: Collect the signal of the special comparison test block; S2: Collect the signal of the test block to be tested; S3: Subtract the signal of the test block to be inspected from the signal of the special comparison test block, and the signal after the subtraction only contains characteristic information related to the defects of the test block to be inspected; S4: Perform full-focus imaging on the signal in S3 to obtain the defect morphology and size of the test block to be inspected.

2. The B-type sleeve detection method based on dual-probe phased array fully focused acoustic projection according to claim 1 is characterized in that: The S4 specifically includes: S41: performing Hilbert transform on the obtained signal; S42: Select the area to be imaged so that the area to be imaged should cover the fillet weld area of ​​the entire sleeve and the mother tube. After calculating the amplitudes of all pixel points, the defect outline and information will be presented on the bottom surface of the mother tube in the imaging image.

3. The B-type sleeve detection method based on dual-probe phased array fully focused acoustic projection according to claim 2 is characterized in that: The S4 also includes S43: Since the location where the defect appears after imaging is not the location of the defect itself, the end point of the defect should be found in combination with the results shown in the traditional full-focus spontaneous emission and self-reception mode or PAUT, and the dual-probe imaging results should be combined with the latter to reversely infer the defect morphology and size.

4. The B-type sleeve detection method based on dual-probe phased array fully focused acoustic projection according to claim 2 is characterized in that: The S42 specifically includes: S421: Taking the first transmitting array element as the starting point, selecting the area to be imaged so that the area to be imaged should cover the fillet weld area of ​​the entire sleeve and the mother tube; S422: Select the first pixel point, calculate the distance and acoustic time from each transmitting array element and receiving array element to the pixel point, index the corresponding amplitude from the collected signal, and perform superposition; S423: Repeat the operation of S422 for all pixels; S424: After calculating the amplitudes of all pixel points, the defect outline and information will be presented at the bottom surface of the mother tube in the imaging image.

5. The B-type sleeve detection method based on dual-probe phased array fully focused acoustic projection according to claim 1 is characterized in that: The S2 specifically includes: Place two linear array probes containing N array elements on the sleeve and the mother pipe to be tested respectively, and keep the array element directions of the two linear array probes consistent. At the same time, record the distances between the centers of the No. 1 array elements of the two linear array probes in the x direction and the z direction respectively.

6. The B-type sleeve detection method based on dual-probe phased array fully focused acoustic projection according to claim 1 is characterized in that: The S1 specifically includes: Place two linear array probes containing N array elements on the comparison sleeve and the comparison mother tube respectively, and keep the array element directions of the two linear array probes consistent. At the same time, record the distances between the centers of the No. 1 array elements of the two linear array probes in the x and z directions respectively.

7. The B-type sleeve detection method based on dual-probe phased array fully focused acoustic projection according to claim 6 is characterized in that: All parameters of the comparison sleeve fillet weld in S1 are consistent with those of the sleeve fillet weld to be tested in S2, and the comparison sleeve fillet weld has no defects.

8. The B-type sleeve detection method based on dual-probe phased array fully focused acoustic projection according to claim 5 or 6, characterized in that: The two linear array probes in S1 and S2 are respectively one-dimensional linear array probes.

9. The B-type sleeve detection method based on dual-probe phased array fully focused acoustic projection according to claim 5 or 6, characterized in that: The two linear array probes in S1 and S2 respectively include the same number of array elements.

10. The B-type sleeve detection method based on dual-probe phased array fully focused acoustic projection according to claim 9, characterized in that: The two linear array probes in S1 and S2 respectively include 16 array elements.

Images