Ultrasonic detection method and device for stainless steel pipeline

Abstract

The invention provides an ultrasonic detection method and device for a stainless steel pipeline, and the method comprises the steps: employing two two-dimensional area array probes, respectively placing the two two-dimensional area array probes at the two sides of the center line of a to-be-detected welding line, enabling each two-dimensional area array probe to achieve the self-serial full-matrix data collection until the whole welding line region is covered, and obtaining the full-matrix data; performing full-focus imaging processing on the full-matrix data to obtain a full-focus imaging processing result; and performing defect identification on the full-focus imaging processing result to obtain a defect result. Two two-dimensional area array probes are adopted and arranged on the two sides of the center line of the weld joint to be detected respectively, each two-dimensional area array probe achieves self-serial full-matrix data collection till the whole weld joint area is covered, and full-matrix data are obtained. And performing full-focus imaging processing on the full-matrix data to obtain a high-definition full-focus imaging processing result.

Description

Technical Field

[0001] This application relates to the field of non-destructive testing technology, and particularly to an ultrasonic testing method and device for stainless steel pipes. Background Art

[0002] Due to the presence of coarse columnar tissue structures in austenitic stainless steel welds, the acoustic wave attenuation is large and the signal-to-noise ratio is low during ultrasonic testing. At the same time, the acoustic beam deflection caused by the anisotropy of the columnar tissue structures makes it difficult to locate defects in ultrasonic testing. In addition, compared with traditional large-angle V-shaped welding grooves, the approximate I-shaped weld groove angle of narrow-gap welds is smaller, and it is necessary to focus on checking the sidewall lack of fusion defects between the weld and the base metal. Since the orientation of the sidewall lack of fusion in narrow-gap welds is close to vertical, when using a single probe for ultrasonic testing, missed detections may occur due to specular reflection. Therefore, usually two inclined probes are added in series front and back, and the one-transmit-one-receive inspection method is used to improve the detection rate of sidewall lack of fusion in narrow-gap welds. However, the two inclined probes in series front and back need to move simultaneously to determine the series reference line and the detection section, which is relatively inconvenient in pipeline inspection. Therefore, developing a suitable ultrasonic testing technology to improve the detection rate of sidewall lack of fusion in narrow-gap welds of stainless steel pipes is a key problem to be solved. Summary of the Invention

[0003] This application provides an ultrasonic testing method and device for stainless steel pipes to solve the problem that the two inclined probes in series front and back need to move simultaneously to determine the series reference line and the detection section, which is relatively inconvenient in pipeline inspection.

[0004] The technical solution adopted by this application to solve its technical problems is: This application provides an ultrasonic testing method for stainless steel pipes, including the following steps:

[0005] S1: Two two-dimensional array probes are used and placed on both sides of the center line of the weld to be tested on the stainless steel pipe. Each of the two-dimensional array probes realizes self-series full matrix data acquisition until the entire weld area is covered to obtain full matrix data;

[0006] S2: The full matrix data is subjected to full focus imaging processing to obtain a full focus imaging processing result;

[0007] S3: Defect identification is performed on the full focus imaging processing result to obtain a defect result.

[0008] In one embodiment, the step S1 includes:

[0009] S1-1: Obtain the attribute data of the weld to be tested on the stainless steel pipe;

[0010] S1-2: Set the acquisition parameters of each two-dimensional array probe according to the attribute data;

[0011] S1-3: For each of the two-dimensional array probes with set acquisition parameters, perform self-serial full matrix data acquisition on the weld to be measured until the entire weld area is covered, and obtain the full matrix data.

[0012] In one embodiment, the two-dimensional array probe includes a first two-dimensional array probe and a second two-dimensional array probe; wherein, the first two-dimensional array probe and the second two-dimensional array probe respectively include a preset number of array elements; the full matrix data includes a first matrix data set and a second matrix data set;

[0013] The step S1-3 includes:

[0014] For the first two-dimensional array probe, activate the array elements one by one as the emission source in a first preset order, and at the same time, all array elements act as receivers to receive the acoustic waves from the emission array elements until all array elements have served as an emission source once and completed the corresponding acoustic wave reception process, thereby generating a first matrix data set including the emission array elements, the receiving array elements, and the time sampling points;

[0015] For the second two-dimensional array probe, activate the array elements one by one to emit acoustic waves in a second preset order, and at the same time, all array elements act as receivers to receive the acoustic waves from the emission array elements until all array elements have served as an emission source once and completed the corresponding acoustic wave reception process, thereby generating a second matrix data set including the emission array elements, the receiving array elements, and the time sampling points.

[0016] In one embodiment, before the step S2, it includes:

[0017] Preprocess the first matrix data set, and use the method of multi-modal full focus imaging to perform delay and weighted synthesis processing on the preprocessed full matrix data to obtain a processed first matrix data set;

[0018] Preprocess the second matrix data set, and use the method of multi-modal full focus imaging to perform delay and weighted synthesis processing on the preprocessed full matrix data to obtain a processed second matrix data set.

[0019] In one embodiment, the step S2 includes:

[0020] S2-1: Perform imaging reconstruction processing on the processed first matrix data set to obtain a first full focus imaging;

[0021] S2-2: Perform imaging reconstruction processing on the processed second matrix data set to obtain a second full focus imaging;

[0022] S2-3: Perform image fusion processing on the first full focus imaging and the second full focus imaging to obtain the full focus imaging processing result.

[0023] In one embodiment, the first full-focus imaging includes a first full-focus image, a second full-focus image, and a third full-focus image;

[0024] The second full-focus imaging includes a fourth full-focus image, a fifth full-focus image, and a sixth full-focus image;

[0025] The step S2-1 includes:

[0026] Performing full-focus imaging on the processed first matrix dataset in direct mode L-L to generate the first full-focus image;

[0027] Performing full-focus imaging on the processed first matrix dataset in self-serial mode LL-L to generate the second full-focus image;

[0028] Performing full-focus imaging on the processed first matrix dataset in self-serial mode TL-L to generate the third full-focus image;

[0029] The step S2-2 includes:

[0030] Performing full-focus imaging on the processed second matrix dataset in direct mode L-L to generate the fourth full-focus image;

[0031] Performing full-focus imaging on the processed second matrix dataset in self-serial mode LL-L to generate the fifth full-focus image;

[0032] Performing full-focus imaging on the processed second matrix dataset in self-serial mode TL-L to generate the sixth full-focus image.

[0033] In one embodiment, the step S2-3 includes:

[0034] Create a new fused image matrix;

[0035] Calculate the signal intensity values of the corresponding pixel points in the first full-focus image, the second full-focus image, the third full-focus image, the fourth full-focus image, the fifth full-focus image, and the sixth full-focus image respectively;

[0036] Take the maximum signal intensity value of each pixel point in all full-focus images as the signal intensity value of the pixel point in the fused image matrix, so as to obtain a fused image matrix with the most significant signal features in all full-focus images.

[0037] In one embodiment, the defect result includes a defect quantitative analysis result, and the step S3 includes:

[0038] Based on the fused image matrix, a preset measurement method is used to quantitatively analyze the defects, and the quantitative analysis result of the defects is obtained.

[0039] In one embodiment, the preset measurement method includes the -6d measurement method.

[0040] This application also provides a stainless steel pipe ultrasonic detection device, including at least two probes, a phased array ultrasonic detector, and a wedge block;

[0041] The two probes are connected by a main shaft, the main shaft is perpendicular to the center line of the weld to be measured, and each probe is respectively connected to the phased array ultrasonic detector; the probe is arranged on the top surface of the wedge block, and the bottom surface of the wedge block is a concave surface with the same outer diameter as the weld to be measured.

[0042] Implementing this application has the following beneficial effects: The present invention uses two two-dimensional array probes, which are respectively placed on both sides of the center line of the weld to be measured. Each two-dimensional array probe realizes self-tandem full matrix data acquisition until the entire weld area is covered, and full matrix data is obtained; the full matrix data is subjected to full focus imaging processing to obtain a full focus imaging processing result; defect recognition is performed on the full focus imaging processing result to obtain a defect result. The present invention uses two two-dimensional array probes, which are respectively placed on both sides of the center line of the weld to be measured. Each two-dimensional array probe realizes self-tandem full matrix data acquisition until the entire weld area is covered, and full matrix data is obtained. The full matrix data is subjected to full focus imaging processing to obtain a high-definition full focus imaging processing result. Description of the Drawings

[0043] The following will further illustrate this application in conjunction with the drawings. In the drawings:

[0044] Figure 1 is a flowchart of a stainless steel pipe ultrasonic detection method of this application;

[0045] Figure 2 is a structural schematic diagram of a stainless steel pipe ultrasonic detection device of this application;

[0046] Figure 3 is a direct mode L-L beam path schematic diagram of a stainless steel pipe ultrasonic detection method of this application;

[0047] Figure 4 is a self-tandem mode LL-L beam path schematic diagram of a stainless steel pipe ultrasonic detection method of this application;

[0048] Figure 5 is a self-tandem mode TL-L beam path schematic diagram of a stainless steel pipe ultrasonic detection method of this application.

[0049] Among them, the component labels are:

[0050] 1 - First two - dimensional array probe; 2 - Second two - dimensional array probe; 3 - Uniaxial pipeline scanner; 4 - Stainless steel pipeline; 5 - First wedge; 6 - Second wedge; Specific embodiments

[0051] The present application will be further described in detail below in conjunction with the accompanying drawings through specific embodiments. Similar elements in different embodiments are labeled with related similar element numbers. In the following embodiments, many detailed descriptions are provided to enable a better understanding of the present application. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other elements, materials, or methods. In some cases, some operations related to the present application are not shown or described in the specification to avoid overwhelming the core part of the present application with excessive descriptions. For those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations based on the descriptions in the specification and general technical knowledge in the art.

[0052] The present application provides a method and device for ultrasonic detection of stainless steel pipelines to solve the problem that the tandem arrangement of two inclined probes requires simultaneous movement to determine the tandem reference line and the detection cross - section, which is inconvenient to operate in pipeline inspection.

[0053] As Figure 1 shown, Figure 1 is a flow chart of a method for ultrasonic detection of stainless steel pipelines according to the present application.

[0054] The technical solution adopted by the present application to solve its technical problems is: The present application provides a method for ultrasonic detection of stainless steel pipelines, including the following steps:

[0055] S1: Use two two - dimensional array probes, which are respectively placed on both sides of the center line of the weld to be measured of the stainless steel pipeline. Each two - dimensional array probe independently performs self - tandem full - matrix data acquisition until the entire weld area is covered to obtain full - matrix data;

[0056] During the data acquisition process, the probe emits and receives ultrasonic signals, and uses the full - matrix capture technology to record all echo data emitted and received by each element, providing a detailed data basis for subsequent full - focus imaging.

[0057] S2: Perform full - focus imaging processing on the full - matrix data to obtain the full - focus imaging processing result;

[0058] This step uses a preset algorithm to process the acquired full - matrix data, and generates a high - resolution full - focus image through virtual focusing technology, so as to clearly display the internal structure and potential defects of the weld.

[0059] S3: Identify defects in the full-focus imaging processing results to obtain defect results.

[0060] It should be noted that the technical solution adopted in this application is optimized specifically for the detection requirements of narrow-gap welds of stainless steel pipes 4. The two two-dimensional array probes are not only symmetrically arranged on both sides of the weld center line, but also through precisely selected probe and wedge parameters, and the use of multi-modal full-focus imaging technology, effectively solving the problem of ultrasonic attenuation caused by the coarse grains of austenitic stainless steel materials. In addition, by fusing the full-focus images from the two probes, the accuracy and reliability of defect detection are further improved. The entire detection process realizes full coverage of the weld by single-axis mechanical scanning, improving the detection efficiency, and at the same time optimizing the delay rule for different acoustic modes to ensure a high detection rate for the specific defects of narrow-gap welds.

[0061] Further, step S1 includes:

[0062] S1-1: Obtain the attribute data of the weld to be measured of the stainless steel pipe 4;

[0063] S1-2: Set the acquisition parameters of each two-dimensional array probe according to the attribute data;

[0064] S1-3: Based on each two-dimensional array probe with set acquisition parameters, perform self-serial full matrix data acquisition on the weld to be measured until the entire weld area is covered to obtain full matrix data.

[0065] In a specific embodiment, the following steps are followed to ensure the effectiveness and accuracy of the detection:

[0066] First, according to the material characteristics of the object to be inspected, such as the ultrasonic attenuation problem caused by the coarse grains of austenitic stainless steel, geometric dimensions, and welding process, select the parameters of the two-dimensional array probe and the wedge. It should be noted that the parameters of the two two-dimensional array probes and their wedges need to be kept consistent to ensure the consistency of the detection. Among them, the wedge is as Figure 2 shown including a first wedge 5 and a second wedge 6.

[0067] Next, due to the particularity of austenitic stainless steel materials, a strategy of symmetrically arranging double probes on both sides of the weld center line is adopted. This arrangement ensures that each probe can effectively detect proximal defects on the same side as the weld and has sufficient signal-to-noise ratio. The probe main axis is perpendicular to the weld center line and scans along the weld center line at a fixed distance. During the scanning process, the full matrix data acquisition technology is used to capture the detailed information inside the weld.

[0068] Finally, based on the collected full matrix data, post - processing is performed on the information within the imaging area. In this step, multi - modal virtual focusing technology is used to generate high - resolution fused images. These images can clearly display the internal structure of the weld and potential defects.

[0069] As Figure 2 shown, specifically, taking the narrow - gap butt weld of the stainless - steel pipe of the fluctuating tube in a nuclear power plant as an example, the outer diameter of the weld is 356 mm, the wall thickness is 36 mm, the material is stainless steel, and the weld groove angle is 6°. According to these parameters, a two - dimensional planar phased array probe with the model number 2.25DM7×4PM - 19×12 - A17 is selected. The center frequency of this probe is 2.25 MHz, the number of array elements is 562×7×4, the center spacing of the main - axis array elements is 2.71 mm, and the center spacing of the secondary - axis array elements is 3 mm. At the same time, a wedge block with the model number N55L - FD40 - AOD356 is selected, its angle is 19.5°, the sound velocity is 2330 m / s, and the roof angle is 1°. To ensure the effective coupling between the probe and the weld, the bottom surface of the wedge block is machined into a concave surface with the same outer diameter as the fluctuating tube.

[0070] During the installation process, the two - dimensional planar phased array probe 1 and probe 2 are symmetrically arranged on the left and right sides of the outer surface of the weld, and the distance from the front end of the probe to the center line of the weld is 20 mm. The sound beam emission directions of the two probes are perpendicular to the center line of the weld. The width of the target imaging area is set to 40 mm, and the height is 36 mm. In this way, it can ensure a comprehensive detection of the entire weld area and obtain accurate full matrix data.

[0071] Furthermore, the two - dimensional planar phased array probe includes the first two - dimensional planar phased array probe 1 and the second two - dimensional planar phased array probe 2; among them, the first two - dimensional planar phased array probe 1 and the second two - dimensional planar phased array probe 2 include a preset number of array elements; the full matrix data includes a first matrix data set and a second matrix data set;

[0072] Step S1 - 3 includes:

[0073] For the first two - dimensional planar phased array probe 1, the array elements are activated one by one in the first preset order as emission sources, and at the same time, all array elements act as receivers to receive the sound waves from the emission array elements until all array elements have served as a single emission source and completed the corresponding sound - wave receiving process, thereby generating a first matrix data set containing emission array elements, receiving array elements, and time sampling points;

[0074] For the second two - dimensional planar phased array probe 2, the array elements are activated one by one in the second preset order to emit sound waves, and at the same time, all array elements act as receivers to receive the sound waves from the emission array elements until all array elements have served as a single emission source and completed the corresponding sound - wave receiving process, thereby generating a second matrix data set containing emission array elements, receiving array elements, and time sampling points.

[0075] In a specific embodiment, a single-axis pipeline scanner 3 is adopted. This scanner is equipped with a two-dimensional array probe 1 and a two-dimensional array probe 2, where probe 1 is the first two-dimensional array probe 1 and probe 2 is the second two-dimensional array probe 2. It is used to perform the acquisition task of full matrix data. There are various types of scanners, including but not limited to pipeline chain scanners and orbital ring scanners, which are all equipped with encoders and can accurately record the circumferential position information during the scanning process.

[0076] The detailed process of full matrix data acquisition is as follows:

[0077] The two-dimensional array probe 1 is equipped with 56 array elements. When these array elements emit sound waves, they will be numbered according to a preset sound wave emission sequence, such as 1, 2,..., 56. In the data acquisition stage, first, the 1st array element emits a sound wave, and then all 56 array elements will act as receivers to jointly capture and receive the sound wave signal, thereby generating 56 echo data. Then, the remaining array elements of probe 1 will successively perform the emission and reception operations until the acquisition of the entire 56×56 matrix data is completed. This data set not only contains the sequence information of the transmitting and receiving array elements but also details the three-dimensional data information of the time sampling points.

[0078] The two-dimensional array probe 2 is also equipped with 56 array elements. However, when emitting sound waves, to distinguish it from probe 1, the numbers of these array elements are set as 65, 66,..., 120. The data acquisition process is the same as that of probe 1, that is, first, the 65th array element emits a sound wave, and then all array elements receive the sound wave signal and generate 56 echo data. Then, the remaining array elements of probe 2 will successively perform the emission and reception operations until the acquisition of the entire 56×56 matrix data is completed. This data set also details the three-dimensional data information of the transmitting array element, the receiving array element, and the time sampling points.

[0079] Through the above process, the integrity and accuracy of the full matrix data can be ensured, laying a solid foundation for subsequent data processing and defect identification.

[0080] Furthermore, before step S2, it includes:

[0081] Preprocess the first matrix data set, and use the method of multi-modal full focus imaging to perform delay and weighted synthesis processing on the preprocessed full matrix data to obtain the processed first matrix data set;

[0082] Preprocess the second matrix data set, and use the method of multi-modal full focus imaging to perform delay and weighted synthesis processing on the preprocessed full matrix data to obtain the processed second matrix data set.

[0083] In a specific embodiment, the principle of the multi-modal full-focus imaging method lies in utilizing the principle of linear superposition of the sound field. When sound waves are emitted from the transmitting array elements and received by the receiving array elements after propagating through the medium, precise time delay and weighting processing can be performed on each received sound wave signal according to the propagation path and time delay of the sound waves. This process realizes the virtual focusing of the sound wave signals, thereby enabling the generation of a high-resolution full-focus image. Through the synthesized amplitude information, the internal structure and potential defects of the weld can be more clearly displayed, providing strong support for subsequent defect identification.

[0084] Further, step S2 includes:

[0085] S2-1: Perform imaging reconstruction processing on the processed first matrix data set to obtain the first full-focus imaging;

[0086] S2-2: Perform imaging reconstruction processing on the processed second matrix data set to obtain the second full-focus imaging;

[0087] S2-3: Perform image fusion processing on the first full-focus imaging and the second full-focus imaging to obtain the full-focus imaging processing result.

[0088] It should be noted that for the imaging reconstruction processing: for the processed first matrix data set, imaging reconstruction processing is performed. This process is based on the principle of multi-modal full-focus imaging and realizes virtual focusing through post-processing techniques such as time delay and weighted synthesis. Utilizing the principle of linear superposition of the sound field, amplitude information is synthesized, thereby generating the first full-focus imaging. This imaging result clearly shows the internal structural characteristics of the weld.

[0089] Similarly, for the processed second matrix data set, imaging reconstruction processing is also performed to obtain the second full-focus imaging. This imaging result complements the first full-focus imaging and jointly provides a comprehensive view of the internal structure of the weld.

[0090] For the image fusion processing: after obtaining the first full-focus imaging and the second full-focus imaging, image fusion processing is performed. This step aims to integrate the effective information in the two imaging results to generate a more comprehensive and accurate image of the internal structure of the weld.

[0091] In a specific embodiment, the maximum value fusion imaging method is adopted. For each image point in the full-focus image, the signal with the strongest signal is selected from the six reconstructed full-focus imaging TFM images of the two two-dimensional array probes as the signal of this image point. Through point-by-point composite superposition, a fused image is finally obtained.

[0092] Such as Figure 3 、 Figure 4 and Figure 5As shown, further, the first full-focus imaging includes a first full-focus image, a second full-focus image, and a third full-focus image;

[0093] The second full-focus imaging includes a fourth full-focus image, a fifth full-focus image, and a sixth full-focus image;

[0094] Step S2-1 includes:

[0095] Performing full-focus imaging on the processed first matrix dataset in the direct mode L-L to generate a first full-focus image;

[0096] Performing full-focus imaging on the processed first matrix dataset in the serial mode LL-L to generate a second full-focus image;

[0097] Performing full-focus imaging on the processed first matrix dataset in the serial mode TL-L to generate a third full-focus image;

[0098] Step S2-2 includes:

[0099] Performing full-focus imaging on the processed second matrix dataset in the direct mode L-L to generate a fourth full-focus image;

[0100] Performing full-focus imaging on the processed second matrix dataset in the serial mode LL-L to generate a fifth full-focus image;

[0101] Performing full-focus imaging on the processed second matrix dataset in the serial mode TL-L to generate a sixth full-focus image.

[0102] It should be noted that the direct mode L-L is a detection mode based on ultrasonic imaging. Its core feature is to use L waves for signal transmission and reception. The longitudinal wave is a mechanical wave whose vibration direction is consistent with the wave propagation direction. It can efficiently propagate in materials and penetrate deeper regions, thereby reflecting the macroscopic structural characteristics inside the materials. In the direct mode L-L, both the transmitting end and the receiving end use longitudinal waves as signal carriers: First, ultrasonic waves are emitted from the transmitting array element in the form of longitudinal waves and enter the interior of the material to be detected; Subsequently, the longitudinal waves propagate in the material and are reflected when encountering internal structures (such as defects, grain boundaries, etc.); The reflected longitudinal wave signals are captured by the receiving array element and subjected to virtual focusing processing through post-processing techniques such as time delay and weighted synthesis, and finally a high-resolution full-focus image is generated. The direct mode L-L has the characteristic of strong penetration ability and can effectively detect specific types of defects in austenitic stainless steel welds, such as cracks, inclusions, etc.

[0103] The serial mode LL-L is an ultrasonic imaging technique based on the reflection signal of longitudinal waves (L-waves). Its name "LL-L" indicates that longitudinal waves (L-waves) are used in the processes of transmission, reflection, and reception. During operation, the transmitting end emits ultrasonic signals in the form of longitudinal waves. The signals propagate inside the material and are reflected after reaching the bottom surface. The reflected longitudinal wave signals are then captured by the array elements at the receiving end. Through post-processing techniques such as time delay and weighted synthesis, the receiving end can generate a full-focus image from the captured signals.

[0104] The serial mode TL-L is an ultrasonic imaging mode that combines transverse waves (T-waves) and longitudinal waves (L-waves). Its name "TL-L" means that the transmitting end uses transverse waves (T-waves), while the reflecting and receiving ends use longitudinal waves (L-waves). In terms of the working principle, ultrasonic waves are emitted from the transmitting array elements in the form of transverse waves. After entering the material, the transverse waves propagate in the material and are reflected when encountering defects or the bottom surface. The reflected signals return in the form of longitudinal waves and are captured by the receiving array elements, and a high-resolution full-focus image is generated through signal processing techniques.

[0105] The serial modes LL-L and TL-L are suitable for detecting sidewall lack of fusion defects in narrow-gap welds because they utilize the bottom surface reflection signal, significantly enhancing the detection sensitivity and detection rate for sidewall defects, and effectively making up for the deficiencies of the direct mode L-L in detecting defects with a direction close to the vertical orientation in the sidewalls of narrow-gap welds.

[0106] First, a series of imaging reconstruction steps were performed on the processed first matrix dataset. Specifically, the direct mode L-L was adopted, using longitudinal waves for transmission and reception, and virtual focusing was achieved through post-processing techniques such as delay and weighted synthesis, thereby generating a first full-focus image that clearly shows the internal structure of the weld, especially the characteristic of coarse grains in the austenitic stainless steel weld. To improve the detection rate of lack of fusion on the sidewall of narrow-gap welds, the self-tandem modes LL-L and TL-L were further used for full-focus imaging, generating a second full-focus image and a third full-focus image respectively. The LL-L mode and the TL-L mode enhance the signal intensity of the lack of fusion defect on the sidewall by using the reflection of ultrasonic waves on the bottom surface, while the TL-L mode combines the transmission and reception of longitudinal waves and transverse waves, improving the detection ability for lack of fusion defects on the sidewall. For the processed second matrix dataset, the same imaging reconstruction steps were also adopted, generating the fourth, fifth, and sixth full-focus images respectively. These images complement each other with the images in the first full-focus imaging, jointly providing a comprehensive view of the internal structure of the weld. When performing multi-modal full-focus imaging reconstruction, based on the principle of linear superposition of sound fields, the post-processing technique of delay and weighted synthesis was adopted, and the full-focus image characterization was realized by synthesizing the amplitude information of acoustic wave signals between different transmit-receive element pairs. Longitudinal waves and transverse waves were used as identifiers for different modes. According to whether the ultrasonic signal passes through the reflection on the bottom surface, it can be represented as different modes such as L-L, LL-L, etc. Considering the characteristics of austenitic stainless steel welds, longitudinal waves were preferentially used as the imaging mode, and two self-tandem modes, LL-L and TL-L, were selected for full-focus imaging to replace the double-probe front-back tandem inspection method in conventional ultrasonic testing, thereby improving the detection accuracy and efficiency.

[0107] Further, step S2-3 includes:

[0108] Create a new fused image matrix;

[0109] Calculate the signal intensity values of the corresponding pixel points in the first full-focus image, the second full-focus image, the third full-focus image, the fourth full-focus image, the fifth full-focus image, and the sixth full-focus image respectively;

[0110] Take the maximum signal intensity value of each pixel point in all full-focus images as the signal intensity value of this pixel point in the fused image matrix, so as to obtain a fused image matrix with the most significant signal features in all full-focus images.

[0111] In one embodiment, in step S2-3, multi-modal full-focus image fusion processing is performed. First, a fused image matrix is newly created to store the final fusion result. Subsequently, the signal intensity values of the corresponding pixel points in the first full-focus image, the second full-focus image, the third full-focus image, the fourth full-focus image, the fifth full-focus image, and the sixth full-focus image are calculated respectively. In order to obtain a fused image containing the most significant signal features in all full-focus images, a maximum value fusion imaging method is adopted. Specifically, for each pixel point in the fused image matrix, the signal intensity value with the maximum value is selected from the six full-focus images, that is, the three TFM images generated by each of the two two-dimensional array probes, as the signal intensity value of this pixel point. This step is repeatedly applied to all pixel points in the inspection area, and finally, a fused image that combines the most significant signal features in all full-focus images is obtained through point-by-point composite superposition. This fused image not only improves the visualization of the internal structure of the weld, but also provides more accurate and comprehensive information for subsequent defect location and quantitative analysis.

[0112] Further, step S3 includes:

[0113] Based on the fused image matrix, a preset measurement method is used to quantitatively analyze the defects to obtain the defect quantitative analysis result.

[0114] Further, the preset measurement method includes the -6d measurement method.

[0115] It should be noted that the -6d measurement method includes -6dB method length measurement and -6dB method height measurement. -6dB method length measurement: In the full-focus image fusion imaging technology, first, the maximum amplitude point of the defect is located. Then, along the length direction of the defect, the positions where the amplitude decreases to -6dB of the maximum amplitude (i.e., decreases to about 50% of the maximum value) are found on both sides respectively. The distance between these two edges is the length of the defect. -6dB method height measurement: Similarly, in the full-focus image fusion imaging technology, first, the maximum amplitude point of the defect is determined. Then, along the depth direction of the defect (usually consistent with the propagation direction of the sound beam), the positions where the amplitude decreases to -6dB of the maximum amplitude are found on both sides respectively. The vertical distance between these two edges is the height of the defect.

[0116] In a specific embodiment, based on the previously obtained fused image matrix, quantitative analysis of the defects in the weld is performed. To achieve this goal, a preset measurement method, namely the -6dB measurement method, is adopted. This method accurately measures the length and height of the detected defects based on the results of multi-modal full-focus image fusion imaging. Through this method, the quantitative analysis results of the defects can be obtained.

[0117] The present application also provides an ultrasonic testing device for a stainless steel pipe 4, which includes at least two probes, a phased array ultrasonic detector, and a wedge block;

[0118] The two probes are connected by a main shaft, the main shaft is perpendicular to the center line of the weld to be measured, and each probe is respectively connected to the phased array ultrasonic detector; the probes are arranged on the top surface of the wedge block, and the bottom surface of the wedge block is a concave surface with the same outer diameter as the weld to be measured.

[0119] The present application provides an ultrasonic testing device for a stainless steel pipe. This device integrates at least two probes, a phased array ultrasonic detector, and a special wedge block. The two probes are tightly connected by a main shaft, and the main shaft is perpendicular to the center line of the weld to be measured, ensuring accurate scanning perpendicular to the weld during the testing process. A wedge block is configured below each probe, and seamless docking is achieved between the probe and the phased array ultrasonic detector through cables or other efficient connection methods to ensure the smooth transmission, reception, and processing of signals.

[0120] The bottom surface of the wedge block adopts a concave surface design that matches the outer diameter of the weld to be measured, enhancing the fit between the wedge block and the weld surface, and further improving the accuracy and reliability of the testing. In addition, this ultrasonic testing device also has the flexibility of being height-adjustable and rotatable, and can easily adapt to the testing requirements of stainless steel pipe 4 welds with different diameters and angles. By flexibly adjusting the positions of the probes and the wedge block, comprehensive coverage testing of each key part of the weld can be achieved, ensuring the integrity and accuracy of the testing results, and providing solid technical support for the quality assessment and repair work of stainless steel pipe 4 welds.

[0121] The outer diameter of the weld is 356 mm, the wall thickness is 36 mm, the material is stainless steel, and the weld groove is 6°. According to these parameters, a two-dimensional matrix phased array probe with the model number 2.25DM7×4PM-19×12-A17 is selected. The center frequency of this probe is 2.25 MHz, the number of array elements is 562×7×4, the center spacing of the main axis array elements is 2.71 mm, and the center spacing of the secondary axis array elements is 3 mm. At the same time, a wedge block with the model number N55L-FD40-AOD356 is selected, its angle is 19.5°, the sound velocity is 2330 m / s, and the roof angle is 1°. In order to ensure effective coupling between the probe and the weld, the bottom surface of the wedge block is machined into a concave surface with the same outer diameter as the fluctuating pipe.

[0122] The two-dimensional matrix probes 1 and 2 are symmetrically arranged on the left and right sides of the outer surface of the weld, and the distance from the front end of the probe to the center line of the weld is 20 mm. The sound beam emission directions of the two probes are perpendicular to the center line of the weld. The width of the target imaging area is set to 40 mm, and the height is 36 mm. In this way, it can ensure comprehensive testing of the entire weld area and obtain accurate full matrix data.

[0123] It is understood that the above embodiments only represent the preferred embodiments of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, by freely combining the above technical features and making several deformations and improvements, these all fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made to the scope of the claims of the present invention shall fall within the scope covered by the claims of the present invention.

Claims

1. A method for ultrasonic detection of stainless steel pipelines, characterized in that: The following steps are involved: S1: Two two-dimensional array probes are used, and are placed on both sides of the center line of the weld to be tested of the stainless steel pipeline. Each of the two-dimensional array probes realizes self-serial full matrix data acquisition until the entire weld area is covered to obtain full matrix data; S2: performing full-focus imaging processing on the full-matrix data to obtain a full-focus imaging processing result; S3: performing defect identification on the full-focus imaging processing result to obtain a defect result.

2. The stainless steel pipeline ultrasonic detection method according to claim 1, characterized in that: The step S1 comprises: S1-1: Obtaining property data of the weld to be tested of the stainless steel pipeline; S1-2: setting acquisition parameters of each of the two-dimensional array probes according to the attribute data; S1-3: Based on the set acquisition parameters of each of the two-dimensional array probes, self-serial full matrix data acquisition is performed on the weld to be measured until the entire weld area is covered to obtain the full matrix data.

3. The stainless steel pipeline ultrasonic detection method according to claim 2, characterized in that: The two-dimensional array probe includes a first two-dimensional array probe and a second two-dimensional array probe; wherein the first two-dimensional array probe and the second two-dimensional array probe respectively include a preset number of array elements; the full matrix data includes a first matrix data set and a second matrix data set; The step S1-3 comprises: For the first two-dimensional array probe, the array elements are activated one by one as the transmitting source according to the first preset order, and all the array elements are used as receivers to receive the sound waves from the transmitting array elements until all the array elements are used as the transmitting source once and complete the corresponding sound wave receiving process, thereby generating a first matrix data set including the transmitting array elements, the receiving array elements and the time sampling points; For the second two-dimensional array probe, the array elements are activated one by one in a second preset order to transmit sound waves, and all array elements act as receivers to receive sound waves from the transmitting array elements until all array elements act as a transmitting source and complete the corresponding sound wave receiving process, thereby generating a second matrix data set including transmitting array elements, receiving array elements and time sampling points.

4. The stainless steel pipeline ultrasonic detection method according to claim 3, characterized in that: The step S2 includes: Preprocessing the first matrix data set, and using a multimodal full-focus imaging method to perform time-delay and weighted synthesis processing on the preprocessed full matrix data to obtain a processed first matrix data set; The second matrix data set is preprocessed, and a multimodal full-focus imaging method is used to perform time delay and weighted synthesis processing on the preprocessed full matrix data to obtain a processed second matrix data set.

5. The stainless steel pipeline ultrasonic detection method according to claim 4, characterized in that: The step S2 comprises: S2-1: performing imaging reconstruction processing on the processed first matrix data set to obtain a first all-focus imaging; S2-2: performing imaging reconstruction processing on the processed second matrix data set to obtain a second all-focus imaging; S2-3: Perform image fusion processing on the first all-focus imaging and the second all-focus imaging to obtain the all-focus imaging processing result.

6. The stainless steel pipeline ultrasonic detection method according to claim 5, characterized in that: The first fully focused image includes a first fully focused image, a second fully focused image, and a third fully focused image; The second fully focused image includes a fourth fully focused image, a fifth fully focused image, and a sixth fully focused image; The step S2-1 comprises: Performing direct mode LL all-focus imaging on the processed first matrix data set to generate the first all-focus image; Performing self-serial mode LL-L all-focus imaging on the processed first matrix data set to generate the second all-focus image; Performing self-tandem mode TL-L all-focus imaging on the processed first matrix data set to generate the third all-focus image; The step S2-2 comprises: performing direct mode LL all-focus imaging on the processed second matrix data set to generate the fourth all-focus image; performing self-serial mode LL-L all-focus imaging on the processed second matrix data set to generate the fifth all-focus image; The processed second matrix data set is subjected to self-serial mode TL-L all-focus imaging to generate the sixth all-focus image.

7. The stainless steel pipeline ultrasonic detection method according to claim 6, characterized in that: The step S2-3 comprises: Create a new fused image matrix; Respectively calculating the signal intensity value of each corresponding pixel point in the first fully focused image, the second fully focused image, the third fully focused image, the fourth fully focused image, the fifth fully focused image, and the sixth fully focused image; The maximum signal intensity value of each pixel in all fully focused images is used as the signal intensity value of the pixel in the fused image matrix to obtain a fused image matrix with the most significant signal features in all fully focused images.

8. The ultrasonic detection method for stainless steel pipelines according to claim 7, characterized in that: The defect result includes a defect quantitative analysis result, and the step S3 includes: Based on the fused image matrix, a preset measurement method is used to perform quantitative analysis on the defects to obtain the defect quantitative analysis results.

9. The stainless steel pipeline ultrasonic detection method according to claim 8, characterized in that: The preset measurement method includes a -6d measurement method.

10. A stainless steel pipeline ultrasonic detection device, characterized in that: It includes at least two probes, a phased array ultrasonic detector and a wedge; The two probes are connected by a main shaft, the main shaft is perpendicular to the center line of the weld to be measured, and each probe is connected to the phased array ultrasonic detector respectively; the probe is arranged on the top surface of the wedge block, and the bottom surface of the wedge block is a concave surface with the same outer diameter as the weld to be measured.

Images