Pipeline ultrasonic detection calibration test block and pipeline ultrasonic detection method

Abstract

The invention provides a pipeline ultrasonic detection calibration test block and a pipeline ultrasonic detection method.The pipeline ultrasonic detection calibration test block comprises a test block body, a plurality of defect grooves are formed in the inner arc surface of the test block body, the groove depths of the defect grooves are different, and at least three calibration transverse holes are formed in the test block body; the vertical distances between the calibration transverse holes and the inner arc surface of the test block body are gradually increased in sequence; sensitivity adjustment in the ultrasonic detection process is achieved through the defect groove, and equivalent discrimination reference is provided for defect detection on a to-be-detected pipeline; a DAC curve is made through calibration transverse holes formed in different depth positions, depth calibration is achieved, a defect signal position judgment reference is provided, and a to-be-detected pipeline can be effectively detected by comparing actual detection signal data with reference detection signal data of defect grooves and the calibration transverse holes in the pipeline ultrasonic detection calibration test block. And the actual defects are accurately positioned and quantified.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pipeline ultrasonic testing, and particularly relates to a pipeline ultrasonic testing calibration test block and a pipeline ultrasonic testing method. BACKGROUND

[0002] In the prior art, the ultrasonic testing technology is commonly used for detecting internal defects of a pipeline. The ultrasonic testing instrument alone cannot determine the degree of internal defects of a material, and can only rely on the comparison between the echo of the instrument and the echo of a certain specific reflector to realize the detection of internal defects of the material. The test piece containing such a specific reflector is collectively referred to as a calibration test block.

[0003] The current ultrasonic testing standard specifies the ultrasonic testing method and quality classification, but the current ultrasonic testing standard is only applicable to the pipeline with the ratio of the inner diameter to the outer diameter greater than 65%, and is only applicable to the weld detection of the pipeline with the ratio of the inner diameter to the outer diameter greater than 70%. For the pipeline body with the ratio of the inner diameter to the outer diameter less than 65% or the pipeline weld with the ratio of the inner diameter to the outer diameter less than 70%, for example, the stainless steel pipeline with a wall thickness of 86 mm in a residue hydrogenation device of a refining enterprise, the conventional probe and method cannot be applied. When the circumferential scanning transverse defects of the pipeline (for example, the pipeline with a specification of 300x86 mm) are performed, the 45° probe beam in the existing standard cannot reach the inner surface of the pipeline, and the defects on the inner surface cannot be detected, and the depth position and size of the defects cannot be determined. SUMMARY

[0004] Therefore, it is necessary to provide a pipeline ultrasonic testing calibration test block and a pipeline ultrasonic testing method to assist in realizing the detection of the internal wall defects of the pipeline with the ratio of the inner diameter to the outer diameter less than 65% and determining the depth position and size of the defects.

[0005] A pipeline ultrasonic testing calibration test block comprises a test block body, the test block body is in a circular arc structure, the curvature radius, thickness and material of the circular arc surface of the test block body are the same as those of a pipeline to be detected, a plurality of defect grooves are arranged on the inner circular arc surface of the test block body, the defect grooves are arranged at intervals, and the groove depths of the defect grooves are different.

[0006] In one embodiment, the number of the calibration transverse holes is three, and the vertical distances of the three calibration transverse holes from the inner circular arc surface of the test block body are 3 mm, 5 mm and 8 mm respectively.

[0007] In one of the embodiments, the distance between the adjacent calibration transverse holes is equal, and the distance between the adjacent calibration transverse holes is greater than the coverage area of the half diffraction angle of the sound velocity of the detection probe.

[0008] In one of the embodiments, one calibration transverse hole is arranged between every two adjacent defect grooves, one defect groove is arranged between every two adjacent calibration transverse holes, and the defect grooves are symmetrically distributed along the symmetry line of the test block body.

[0009] In one of the embodiments, the distance between the adjacent defect grooves is greater than the coverage area of the half diffraction angle of the sound velocity of the detection probe.

[0010] In one of the embodiments, the defect groove is a rectangular groove.

[0011] In one of the embodiments, the number of the defect grooves is four, and the groove depths of the four defect grooves are 0.5 mm, 1 mm, 2 mm and 3 mm respectively.

[0012] In one of the embodiments, the width of the test block body is greater than the maximum sound path of the probe sound beam propagating in the pipeline to be detected.

[0013] In one of the embodiments, the number of the test block bodies is multiple, and at least one of the test block bodies is provided with a weld joint at the position of the central axis.

[0014] The application also provides a pipeline detection method based on the pipeline ultrasonic detection calibration test block.

[0015] S101, moving the ultrasonic detection probe towards the surface of the test block body, aligning the defect groove on the test block body with the ultrasonic detection probe and performing scanning, finding the position of the highest wave, and calibrating the sensitivity of the ultrasonic detection according to the position of the highest wave;

[0016] S102, moving the ultrasonic detection probe to align the calibration transverse hole on the test block body with the ultrasonic detection probe respectively and performing scanning, generating the reference sound path and the first reflection signal amplitude of the multiple calibration transverse holes, adjusting the sound path according to the reference sound path, and making a DAC curve;

[0017] S103, moving the ultrasonic detection probe towards the pipeline to be detected and performing scanning to generate the defect signal sound path and the defect signal amplitude, comparing the defect signal sound path with the DAC curve to determine the position of the defect;

[0018] S104, comparing the defect signal amplitude with the first reflection signal amplitude to determine the equivalent size of the defect;

[0019] S105, moving the ultrasonic detection probe towards the weld seam test block body, moving the ultrasonic detection probe to be aligned with the defect groove and the calibration transverse hole of the weld seam test block body respectively, and performing scanning to generate a second reflection signal amplitude, and determining the detection sensitivity of the defect according to the difference between the second reflection signal amplitude and the ultrasonic detection instrument noise signal amplitude.

[0020] The technical scheme has the following technical effects:

[0021] The pipeline ultrasonic detection calibration test block provided by the application comprises a test block body, a plurality of defect grooves are arranged on the inner arc surface of the test block body, the groove depths of the defect grooves are different, at least three calibration transverse holes are arranged on the test block body, and the vertical distances from the calibration transverse holes to the inner arc surface of the test block body are sequentially increased. The defect grooves are used to adjust the sensitivity in the ultrasonic detection process and provide equivalent discrimination reference for defect detection on the pipeline to be detected. The calibration transverse holes arranged at different depth positions are used to make a DAC curve, realize depth calibration, and provide defect signal position discrimination reference. In this way, the pipeline ultrasonic detection calibration test block is used to assist the ultrasonic detection instrument in detecting the stainless steel pipeline with an inner diameter to outer diameter ratio less than 65%, and through comparison of actual detection signal data and reference detection signal data of the defect grooves and the calibration transverse holes on the pipeline ultrasonic detection calibration test block, the pipeline to be detected can be effectively detected, and the actual defect can be accurately positioned and quantified. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a structural schematic view of the pipeline ultrasonic detection calibration test block in an embodiment;

[0023] Figure 2 It is a structural schematic view of the pipeline ultrasonic detection calibration test block in an embodiment; Figure 1 It is another direction view of the pipeline ultrasonic detection calibration test block in the embodiment;

[0024] Figure 3 It is a structural schematic view of the pipeline ultrasonic detection calibration test block in another embodiment;

[0025] Figure 4 It is a structural schematic view of the pipeline ultrasonic detection calibration test block in another embodiment; Figure 3 It is another direction view of the pipeline ultrasonic detection calibration test block in the embodiment;

[0026] Figure 5 It is a structural schematic view of the pipeline ultrasonic detection calibration test block (weld seam is arranged on the calibration test block) in another embodiment;

[0027] Figure 6 It is a structural schematic view of the pipeline ultrasonic detection calibration test block in another embodiment; Figure 5 It is another direction view of the pipeline ultrasonic detection calibration test block in the embodiment;

[0028] Figure 7A flowchart of a pipeline ultrasonic testing method in one embodiment.

[0029] Label description:

[0030] 100, test block body; 110, defect groove; 120, calibration horizontal hole; 130, weld; d, vertical distance; h, groove depth. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0032] Embodiment one

[0033] In this embodiment, referring to Figures 1 to 6 , a pipeline ultrasonic testing calibration test block is provided, which is suitable for ultrasonic testing of stainless steel pipelines with an inner diameter to outer diameter ratio of less than 65%, such as stainless steel pipelines provided in a residue hydrogenation device in a refining enterprise. Because the inner diameter to outer diameter ratio of the stainless steel pipeline is less than 65%, the curvature change of the inner diameter and the outer diameter is large, and in the process of ultrasonic wave propagation in ultrasonic testing, phenomena such as attenuation, refraction and deviation are prone to occur, which greatly affects the accuracy of the test results, resulting in that the detection of the pipeline in the prior art cannot be effectively realized, and the risk of the pipeline in use is increased. The present application is applied to ultrasonic testing of stainless steel pipelines with an inner diameter to outer diameter ratio of less than 65%. It is worth mentioning that the inner surface of the stainless steel pipeline is prone to cracking, so for cracking and weld defects, the present application develops the pipeline ultrasonic testing calibration test block, which is used to adjust the sensitivity in the ultrasonic testing process, and to distinguish and reference the defect signal position and equivalent of the pipeline to be tested.

[0034] Referring to Figure 1 , Figure 3 and Figure 5 , the pipeline ultrasonic testing calibration test block includes a test block body 100, the test block body 100 is a circular arc structure, the curvature radius, thickness and material of the circular arc surface of the test block body 100 are the same as those of the pipeline to be tested; a plurality of defect grooves 110 are formed in the inner circular arc surface of the test block body 100, the defect grooves 110 are arranged at intervals, and the groove depths h of the defect grooves 110 are different; at least three calibration horizontal holes 120 are formed in the outer circular arc surface of the test block body 100 towards the inner circular arc surface, the depths of the calibration horizontal holes 120 are less than the thickness of the test block body 100, the vertical distances d of the calibration horizontal holes 120 from the inner circular arc surface of the test block body 100 are sequentially increased, the hole diameters of the calibration horizontal holes 120 are equal, and the calibration horizontal holes 120 are arranged at intervals.

[0035] This application utilizes multiple defect grooves 110 of varying depths on the inner arc surface of the test block body 100 to adjust the sensitivity during ultrasonic testing and provide equivalent discrimination references for defect detection on the pipeline under test. Simultaneously, by creating DAC curves through at least three calibration transverse holes 120 with sequentially increasing vertical distances d from the inner arc surface of the test block body 100, depth calibration and defect signal location discrimination references are achieved. Thus, the pipeline ultrasonic testing calibration test block assists ultrasonic testing instruments in ultrasonic testing stainless steel pipelines with an inner diameter to outer diameter ratio of less than 60%. By comparing the actual test signal data with the reference test signal data from the defect grooves 110 and calibration transverse holes 120 on the pipeline ultrasonic testing calibration test block, the pipeline under test can be effectively tested, and the actual defects can be accurately located and quantified.

[0036] In this embodiment, to ensure consistency with the ultrasonic testing object, i.e., the pipe to be tested, the radius of curvature, thickness, and material of the arc surface of the test block body 100 are all consistent with those of the pipe to be tested. Specifically, ultrasonic testing calibration test blocks 100 with different curvatures and thicknesses can be manufactured according to different specifications of the pipe to be tested. (See also...) Figures 1 to 4 As shown, for example, the specifications of the pipeline ultrasonic testing calibration block 100 can be set according to the specifications of the pipeline to be tested: wait.

[0037] It should be understood that due to the curvature of the pipe under test and the fact that the pipe inspection surface is an arc, when the ultrasonic testing probe inspects along the circumference of the pipe, the instrument cannot directly display the accurate depth of the defect. Complex calculations using formulas are required, leading to difficulties in locating the detected defect. Therefore, this solution involves creating multiple calibration transverse holes 120 on the test block body 100, with progressively increasing vertical distances (d) from the inner arc surface of the test block body 100. This generates a DAC curve, which represents the sound path position of the reflected echoes from the multiple calibration transverse holes 120 within the ultrasonic instrument. The DAC curve allows for adjustment of the detection sound path, enabling calibration of the defect sound path position during ultrasonic testing and thus determining the approximate location of the defect.

[0038] Specifically, the inner wall defects of the stainless steel pipeline are mostly cracks, and the inner surface cracks of the pipeline mostly extend along the direction perpendicular to the inner surface of the pipeline, so the depth position parameter of the cracks is certain, and is basically the wall thickness of the pipeline; the DAC curve represents the corresponding sound path positions of the reflected echoes of the calibration transverse holes 120 with different vertical distances (i.e., different opening depth positions) from the inner arc surface of the test block body 100 in the ultrasonic instrument. During the detection of the pipeline to be detected, according to the DAC curve, the sound path position of the defect signal on the pipeline to be detected is adjusted, that is, the calibration of the defect position is realized. In addition, the reference sound path of the calibration transverse hole 120 with different opening depth positions of the test block body 100 and the defect signal sound path on the pipeline to be detected are compared to determine the approximate position of the defect, and at the same time, the equivalent size of the defect is determined by comparing the amplitude of the defect signal on the pipeline to be detected with the amplitude of the reflected signal of the calibration transverse hole 120 or the rectangular groove 110.

[0039] Wherein, DAC (English Distance amplitude curve) curve, that is, distance-amplitude curve; the DAC curve in the prior art is more troublesome to make, and the traditional instrument sound path adjustment is mainly used for flat workpieces, and it is difficult to adjust the sound path and defect positioning of the curved pipe to the right position, and the error after adjustment is large. Since the present application detects the inner wall defects of the pipeline, the same specification test block body 100 as the pipeline to be detected is made, and the sound path is adjusted and calibrated through the plurality of calibration transverse holes 120, so that the actual position of the defect can be quickly determined, and whether the defect is an inner surface defect can be distinguished. Since the calibration distance is close to the inner wall, the accuracy is higher, and the calibration speed is faster.

[0040] In the embodiment, the number of the calibration transverse holes 120 with the vertical distance d from the inner arc surface of the test block body 100 increasing in turn is three, and the DAC curve can be made through the three calibration transverse holes 120. Of course, in other embodiments, the number of the calibration transverse holes 120 can also be 4, 5, etc., so as to improve the accuracy of the DAC curve, which is not limited herein.

[0041] In one of the embodiments, the aperture of the calibration transverse hole 120 is 2 mm. The aperture of the calibration transverse hole 120 with a size of 2 mm is relatively easy to find, so it is set as the aperture of the calibration transverse hole 120 on the test block body 100. In other embodiments, the aperture of the calibration transverse hole 120 can also be 1 mm, 3 mm, etc., which is not limited herein.

[0042] In one of the embodiments, referring to Figure 1 and Figure 3As shown, the vertical distances d of the three calibration holes 120 from the inner arc surface of the test block body 100 are 3mm, 5mm and 8mm respectively. In order to avoid the interference of the side wall of the test block body 100 and ensure the rationality of the distribution, the vertical distance d is set to 3mm, 5mm and 8mm in a stepwise increasing manner. Of course, in other embodiments, the vertical distance d of the calibration hole 120 from the inner arc surface of the test block body 100 can also be 4mm, 6mm and 9mm, etc., which is not limited herein.

[0043] In one embodiment, the distance between adjacent calibration holes 120 is equal, and the distance between adjacent calibration holes 120 is greater than the coverage area of the half diffusion angle of the detection probe sound velocity. The formula for calculating the half diffusion angle is: half diffusion angle (θ) = arcsin (1.22λ / Ds), λ is the wavelength of the ultrasonic wave (unit: meter), and Ds is the effective aperture of the ultrasonic probe (unit: meter). When setting the distance between adjacent calibration holes 120, the signal interference between the two adjacent calibration holes 120 is mainly considered, so that by setting the distance between adjacent calibration holes 120 to be greater than the coverage area of the half diffusion angle of the detection probe sound velocity, the signal interference between the two calibration holes 120 during detection can be effectively avoided.

[0044] In one embodiment, referring to Figure 1 and Figure 3 As shown, a calibration hole 120 is arranged between every two adjacent defect grooves 110, and a defect groove 110 is arranged between every two adjacent calibration holes 120. The defect grooves 110 and the calibration holes 120 are distributed alternately and symmetrically along the symmetry line of the test block body 100. In this embodiment, the defect grooves 110 and the calibration holes 120 are arranged in a plum blossom pattern, which ensures the rationality of the distribution of the defect grooves 110 and the calibration holes 120 on the test block body 100, and avoids interference between the defect grooves 110 and the calibration holes 120.

[0045] In one embodiment, the distance between adjacent defect grooves 110 is greater than the coverage area of the half diffusion angle of the detection probe sound velocity. When setting the distance between adjacent defect grooves 110, the signal interference between the two adjacent defect grooves 110 is mainly considered, so that by setting the distance between adjacent defect grooves 110 to be greater than the coverage area of the half diffusion angle of the detection probe sound velocity, the signal interference between the two defect grooves 110 during detection can be effectively avoided.

[0046] In one embodiment, the defect groove 110 is a rectangular groove. In the prior art, there are various ways to simulate defects on the test block, such as opening a horizontal hole, a V-groove, a rectangular groove, etc. The inventors of the present scheme have summarized the defects on the inner wall of the stainless steel pipeline and found that the defects on the inner wall of the stainless steel pipeline are mostly cracks. Therefore, according to the propagation route of the ultrasonic detection probe beam and the detectability of the echo, through the analysis and comparison of various horizontal holes and grooves, it is found that when the defect groove 110 is a rectangular groove, the end angle reflection and vertical reflection of the detection beam can be realized, which is convenient for sensitivity calibration.

[0047] In one embodiment, referring to Figure 1 and Figure 3 , the number of the defect groove 110 is four, and the groove depth h of the four defect grooves 110 is 0.5mm, 1mm, 2mm and 3mm respectively. Based on the structure size and detection accuracy requirement of thick-walled stainless steel pipeline, the defect groove 110 with a depth of 0.5mm is the limit sensitivity of ultrasonic detection, so it is set as the minimum defect depth of the defect groove 110 on the test block body 110. Similarly, the defect groove 110 with a depth of 3mm is also a relatively easy-to-find defect size, so it is set as the maximum defect depth of the defect groove 110 on the test block body 110. Considering that the length-depth ratio of the actual defect on the stainless steel pipeline is uncertain, the length of the defect groove 110 is not specified in the test block body 100, and the user determines the length of the defect groove 110 according to the actual defect characteristics of different specifications of stainless steel pipeline.

[0048] In one embodiment, the width of the test block body 100 is greater than the maximum sound path of the probe beam propagating in the pipeline to be detected. In this way, when the width of the test block body 100 is small, the sidewall of the test block body 100 interferes with the propagation of the probe beam in the defect groove 110 and the standard horizontal hole 120 during ultrasonic detection, affecting the detection result.

[0049] In one embodiment, the defect groove 110 and the standard horizontal hole 120 are both opened by electric spark machining. Electric spark machining is a machining method by discharging and etching, which has high precision, flexibility and stable machining quality, ensuring accurate machining of the defect groove 110 and the standard horizontal hole 120.

[0050] In one embodiment, referring to Figure 5 and Figure 6As shown, the number of pipeline ultrasonic testing calibration test blocks is multiple, and at least one test block body 100 is provided with a weld 130 at the position of the central axis. In this embodiment, in order to better simulate the on-site testing situation and effectively verify the testing process, the defect groove and calibration transverse hole in the test block body 100 with a weld are detected, and the detection sensitivity of the defect is determined according to the difference between the reflection signal amplitude of the corresponding defect groove or calibration transverse hole and the instrument noise signal amplitude.

[0051] Embodiment two

[0052] In this embodiment, referring to Figures 5 to 7 As shown, a pipeline ultrasonic testing method is provided, which is realized based on the pipeline ultrasonic testing calibration test block as described in embodiment 1, referring to Figure 7 As shown, the method comprises the following steps:

[0053] S101, moving the ultrasonic testing probe towards the surface of the test block body, moving the ultrasonic testing probe to align with the defect groove on the test block body and perform scanning, finding the position of the highest wave, and calibrating the sensitivity of ultrasonic testing according to the position of the highest wave;

[0054] S102, moving the ultrasonic testing probe to align with the calibration transverse hole on the test block body respectively, and performing scanning to generate the reference sound path and the first reflection information amplitude of multiple calibration transverse holes, adjusting the sound path according to the reference sound path, and making a DAC curve;

[0055] S103, moving the ultrasonic testing probe towards the pipeline to be tested, moving the ultrasonic testing probe to perform scanning to produce the defect signal sound path and the defect signal amplitude, comparing the defect signal sound path with the DAC curve to determine the approximate position of the defect;

[0056] S104, comparing the defect signal amplitude with the first reflection signal amplitude to determine the equivalent size of the defect;

[0057] S105, moving the ultrasonic testing probe towards the test block body with a weld, moving the ultrasonic testing probe to align with the defect groove and the calibration transverse hole of the test block body with a weld respectively, and performing scanning to generate the second reflection signal amplitude, and determining the detection sensitivity of the defect according to the difference between the second reflection signal amplitude and the ultrasonic testing instrument noise signal amplitude.

[0058] When the pipe ultrasonic testing calibration block is used for ultrasonic testing of the pipe to be tested, the sensitivity in the ultrasonic testing process can be adjusted through the defect groove, and the equivalent discrimination reference for the defect testing on the pipe to be tested is provided; and the DAC curve is made through the calibration transverse holes opened at different depth positions, the depth calibration is realized, and the defect signal position discrimination reference is provided. In this way, through comparison of the actual testing signal data and the reference testing signal data of the defect groove and the calibration transverse holes on the pipe ultrasonic testing calibration block, the pipe to be tested can be effectively tested, and the actual defect can be accurately positioned and quantified.

[0059] The technical features of the above embodiments can be combined in any manner. To make the description simple, all possible combinations of the technical features in the above embodiments are not described, but as long as the combinations of the technical features do not contradict, they should be considered as falling within the scope of the present disclosure.

[0060] The above embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all fall within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A pipeline ultrasonic inspection calibration test block, characterized by, The test block body is in a circular arc structure, and the curvature radius, thickness, and material of the circular arc surface of the test block body are the same as those of the pipeline to be detected.

2. The pipe ultrasonic inspection calibration test block of claim 1, wherein, The number of the calibration transverse holes is three, and the vertical distances of the three calibration transverse holes from the inner circular arc surface of the test block body are 3 mm, 5 mm, and 8 mm respectively.

3. The pipe ultrasonic inspection calibration test block of claim 1, wherein, The spacing between adjacent calibration transverse holes is equal, and is greater than the coverage area of the half diffusion angle of the sound velocity of the detection probe.

4. The pipe ultrasonic inspection calibration test block of claim 1 or 3, wherein, One calibration transverse hole is arranged between every two adjacent defect grooves, and one defect groove is arranged between every two adjacent calibration transverse holes and is symmetrically distributed along the symmetry line of the test block body.

5. The pipe ultrasonic inspection calibration test block of claim 4, wherein, The spacing between adjacent defect grooves is greater than the coverage area of the half diffusion angle of the sound velocity of the detection probe.

6. The pipe ultrasonic inspection calibration test block of claim 1, wherein, The defect groove is a rectangular groove.

7. The pipe ultrasonic inspection calibration test block of claim 1 or 6, wherein, The number of the defect grooves is four, and the groove depths of the four defect grooves are 0.5 mm, 1 mm, 2 mm, and 3 mm respectively.

8. The pipe ultrasonic inspection calibration test block of claim 1, wherein, The width of the test block body is greater than the maximum sound path of the sound beam of the probe propagating in the pipeline to be detected.

9. The pipe ultrasonic inspection calibration test block of claim 1, wherein, The number of the test block bodies is multiple, and at least one test block body is provided with a weld on the position of the central axis.

10. A method of pipeline inspection, implemented based on the ultrasonic pipeline inspection calibration block according to any one of claims 1 to 9, characterized in that, The method comprises the following steps: S101, moving the ultrasonic detection probe towards the surface of the test block body, aligning the defect groove on the test block body with the ultrasonic detection probe, and performing scanning to find the position of the highest wave, and calibrating the sensitivity of ultrasonic detection according to the position of the highest wave; S102, moving the ultrasonic detection probe to align the calibration transverse holes on the test block body with the ultrasonic detection probe respectively, and performing scanning to generate reference sound paths and first reflection signal amplitudes of the multiple calibration transverse holes, adjusting the sound path according to the reference sound paths, and making a DAC curve; S103, moving the ultrasonic detection probe towards the pipeline to be detected, and performing scanning to generate defect signal sound paths and defect signal amplitudes, comparing the defect signal sound paths with the DAC curve to determine the position of the defect; S104, comparing the defect signal amplitudes with the first reflection signal amplitudes to determine the equivalent size of the defect; S105, moving the ultrasonic detection probe towards the test block body with a weld, aligning the defect groove and the calibration transverse hole of the test block body with the weld with the ultrasonic detection probe respectively, performing scanning to generate second reflection signal amplitudes, and determining the detection sensitivity of the defect according to the difference between the second reflection signal amplitudes and the noise signal amplitude of the ultrasonic detection instrument.

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