Ray digital imaging nondestructive testing method for weld defects of pipelines with different wall thicknesses
Through the non-destructive detection method of radio digital imaging, the problem that existing equipment cannot efficiently and accurately detect defects of unequal wall thickness pipeline welds is solved, and efficient and accurate detection of unequal wall thickness pipeline welds is achieved, ensuring the stability and safety of the detection results.
Patent Information
- Application Number
- CN202311810873.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-26
- Publication Date
- 2025-06-27
AI Technical Summary
Existing equipment cannot efficiently and accurately non-destructive testing of weld defects in pipes with unequal wall thickness, especially in the case of concentrated stress and high risk of cracking.
The non-destructive detection method of radiation digital imaging is adopted, and by determining the detection standards and technical levels, obtaining weld information of pipes with different wall thicknesses, selecting appropriate detection equipment, and setting equipment parameters based on the weld information, collecting images for detection. The specific steps include placing single-line and double-line image meters, setting X-ray machine parameters, collecting images and determining whether the detection process and equipment meet the standards, and finally classifying the weld quality.
It realizes efficient and accurate non-destructive testing of weld defects in unequal wall thickness pipelines, reduces the workload during the inspection process, ensures the stability of the inspection results and the accuracy of data, reduces the radiation range, and improves the safety and environmental protection of the inspection.
Smart Images
Figure CN120213981A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of non-destructive testing for welds of pipes with unequal wall thicknesses, and particularly relates to a method for non-destructive testing of weld defects of pipes with unequal wall thicknesses by means of radiographic digital imaging. Background Art
[0002] In natural gas stations, the risk of stress concentration cracking in girth welds with variable wall thicknesses is high. The problem of welding pipes with unequal wall thicknesses affects the alignment and welding during the installation process. If not properly handled, it is likely to cause stress concentration and affect the welding quality. The butt joint of welds with unequal wall thicknesses is divided into two cases: internal alignment and external alignment. When the inner diameters of the workpieces are unequal, it is difficult to penetrate the root during the welding process, which seriously reduces the fatigue strength of the weld and may cause the weld to fail and become a crack source; when the outer diameters of the workpieces are unequal, a gradient will be formed at the weld joint, creating a stress concentration point, and the stress concentration point is prone to becoming a cracking source, resulting in a cracking risk. Traditional radiographic testing is difficult to quickly detect weld defects of pipes with unequal wall thicknesses. Due to the wall thickness difference in radiographic testing, there are often shadows on the radiographic film on the thin-wall side, thus masking the quality problem of the root. Summary of the Invention
[0003] The object of the present invention is to provide a method for non-destructive testing of weld defects of pipes with unequal wall thicknesses by means of radiographic digital imaging, which solves the problem that existing equipment cannot efficiently and accurately perform non-destructive testing on weld defects of pipes with unequal wall thicknesses.
[0004] The technical solution adopted by the present invention is that a method for non-destructive testing of weld defects of pipes with unequal wall thicknesses by means of radiographic digital imaging is specifically implemented according to the following steps: Step 1: Determine the detection standard and the detection technology level; Step 2: Determine the weld information of the pipes with unequal wall thicknesses; Step 3: Select the detection equipment and set the relevant parameter ranges of the detection equipment according to the weld information of the pipes with unequal wall thicknesses; Step 4: Place a single-line image quality indicator and a double-line image quality indicator across the weld, and use the detection equipment to collect images of the pipes with unequal wall thicknesses to determine whether the detection process and the detection equipment meet the standards; Step 5: Grade the quality of the pipes with unequal wall thicknesses according to the images of the pipes with unequal wall thicknesses.
[0005] The characteristics of the present invention also lie in that: The weld information of the pipes with unequal wall thicknesses includes the shape of the pipes with unequal wall thicknesses, the welding method, the pipe wall thickness, and the weld material.
[0006] The detection equipment includes an X-ray machine, a flat panel detector system, a filter plate, a single-line image quality indicator, a double-line image quality indicator, an identification device, a detection tooling, a computer hardware system, a display, and a computer software system.
[0007] Setting the relevant parameter ranges of the detection equipment according to the weld information of the pipes with unequal wall thicknesses specifically includes: Select the energy range of the X-ray machine according to the penetration thickness, material, and focal length, in accordance with the exposure curve graph of the X-ray machine in use. The flat panel detector system includes a flat panel detector with a built-in A / D converter and accessories. The flat panel detector is docked with the accessories through a socket. The number of bits of the A / D converter in the flat panel detector is not less than 12 bits. The flat panel detector has a built-in bad pixel table and a bad pixel correction method, and the dynamic range of the flat panel detector should not be less than 2000:1.
[0008] The accessories include a network connection cable, a power adapter, a wireless router, and a computer loaded with flat panel detector control software.
[0009] The specific process of step 4 for acquiring images of pipes with unequal wall thicknesses is as follows: Place the single-line image quality indicator and the double-line image quality indicator across the weld. Set the thin-wall side of the base metal of the weld with unequal wall thicknesses as the starting point for the X-ray machine to scan. The X-ray machine emits X-rays to scan the pipe with unequal wall thicknesses. The attenuated signal is received by the flat panel detector system, and the signal intensity at different positions is presented in a continuous imaging manner to obtain a signal intensity image, which is the image of the pipe with unequal wall thicknesses.
[0010] When the X-ray machine emits X-rays to scan the pipe with unequal wall thicknesses, the scanning speed of the inspected pipe with unequal wall thicknesses matches the frame rate of image acquisition. At the same time, the main X-ray beam perpendicularly penetrates the pipe with unequal wall thicknesses and reaches the effective imaging area of the flat panel detector system.
[0011] The specific process of step 4 for determining whether the inspection process and inspection equipment meet the standards is as follows: Based on the single-line image quality indicator in the image of the pipe with unequal wall thicknesses, determine the single-line wire number according to the inspection technology level; determine the single-line standard wire number in the inspection standard based on the weld information of the pipe with unequal wall thicknesses, and compare to determine whether the single-line wire number meets the single-line standard wire number. Based on the double-line image quality indicator in the image of the pipe with unequal wall thicknesses, calculate the double-line wire number according to the inspection technology level; determine the double-line standard wire number in the inspection standard based on the weld information of the pipe with unequal wall thicknesses, and compare to determine whether the calculated double-line wire number meets the double-line standard wire number. If the single-line wire number meets the single-line standard wire number and the double-line wire number meets the double-line standard wire number, then the inspection process and inspection equipment meet the standards; otherwise, the inspection process does not meet the standards or the inspection equipment does not meet the standards. Adjust the inspection equipment or the relevant parameter range of the inspection equipment, and re-execute step 4.
[0012] The specific process of step 5 is as follows: Judge the defect type and defect length on the image of the pipe with unequal wall thicknesses to grade the inspected weld.
[0013] The beneficial effects of the present invention are: The ray digital imaging non-destructive testing method for weld defects of pipes with unequal wall thicknesses in the present invention solves the problem that existing equipment cannot efficiently and accurately perform non-destructive testing on weld defects of unequal wall thicknesses; the testing method of the present invention combines the difficulties of ray testing for unequal wall thicknesses, stipulates the parameter selection and precautions during the testing operation of unequal wall thickness welds, reduces the redundant workload during the testing process, and at the same time ensures the stability of the testing results and the accuracy of the data. The testing method of the present invention can achieve non-destructive testing of on-site welds of pipes with unequal wall thicknesses, laying a foundation for the efficient and accurate detection of weld defects of unequal wall thicknesses in steel pipes. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 is the flow chart of the ray digital imaging non-destructive testing method for weld defects of pipes with unequal wall thicknesses in the present invention; Figure 2 is the schematic diagram of the selection of the tube voltage for X-ray machine irradiation in the present invention, where the maximum tube voltage allowed by NB / T47013.11 should be satisfied with the thickness transformation; Figure 3 is the schematic diagram of the relative position between the testing equipment and the testing area in Embodiment 3 of the present invention; Figure 4 is the schematic diagram of the identification of the radiographic film in Embodiment 3 of the present invention Figure 5 is the measurement diagram of the single-line type IQI and double-line type IQI in the embodiments of the present invention; Figure 6 is the schematic diagram of the single wire basis adopted in the embodiments of the present invention; Figure 7 is the schematic diagram of the double wire basis adopted in the embodiments of the present invention; Figure 8 is the schematic diagram of the basis for the decomposition and evaluation of the quality of strip defects required by 4.18 in SY / T 4109-2020 in the embodiments of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0015] The present invention will be described in detail below in conjunction with the drawings and specific embodiments.
[0016] Embodiment 1 Compared with traditional film photography, the use of ray digital imaging non-destructive testing technology in welds of unequal wall thicknesses in natural gas stations can improve the testing efficiency and shorten the testing work cycle. At the same time, the required ray dose for imaging is relatively small, the imaging time is very short, it can effectively reduce the radiation range, and it is safer and more environmentally friendly in actual use. Moreover, the testing process is very easy to control, the obtained testing results can be analyzed and processed by computer programs, and stored and transmitted electronically, with less time used and can be permanently saved. The ray digital imaging non-destructive testing method for weld defects of pipes with unequal wall thicknesses in the present invention, as Figure 1As shown in the figure, the implementation is specifically carried out according to the following steps: Determine the detection standard and detection technology level; Determine the weld information of the unequal wall thickness pipeline; Select the detection equipment and set the relevant parameter range of the detection equipment according to the weld information of the unequal wall thickness pipeline; Place the single-line image quality indicator and the double-line image quality indicator across the weld, and use the detection equipment to collect the images of the unequal wall thickness pipeline to judge whether the detection process and the detection equipment meet the standards; Classify the quality of the unequal wall thickness pipeline according to the images of the unequal wall thickness pipeline. In view of the engineering problems existing in the defects of the steel pipeline with unequal wall thickness welds, the present invention proposes to formulate a standardized operation method for the radiographic testing of the defects of the steel pipeline with unequal wall thickness welds, and makes corresponding regulations on the radiographic digital imaging detection system, the relevant factors considered in the detection process, the radiographic digital imaging detection method and evaluation of the unequal wall thickness welds, so as to efficiently and accurately detect the defects of the unequal wall thickness pipeline welds. It ensures the accuracy and repeatability of the radiographic testing results and provides technical support for the radiographic digital imaging detection of the steel pipeline with unequal wall thickness welds.
[0017] Embodiment 2 The radiographic digital imaging non-destructive testing method for the defects of the welds of the unequal wall thickness pipeline of the present invention, as Figure 1 shown, is specifically carried out according to the following steps: Step 1: Determine the detection standard and detection technology level; In view of the many problems existing in the detection results of the unequal wall thickness weld defects, different detection standards are determined for different application scenarios. The standard used for the non-destructive testing of the steel pipeline welds in oil and gas is SY / T4109-2020, and the commonly used standard for the non-destructive testing of pressure-bearing equipment is NB / T47013-2021. The detection technology levels are divided into level A, AB level, and B level, and the commonly used ones are AB level and B level.
[0018] Step 2: Determine the weld information of the unequal wall thickness pipeline; The weld information of the unequal wall thickness pipeline includes the shape of the unequal wall thickness pipeline, the welding method, the pipeline wall thickness, and the weld material.
[0019] Step 3: Select the detection equipment (including X-ray machine, flat panel detector system, filter plate, single-line image quality indicator, double-line image quality indicator, marking device, detection tooling, computer hardware system, display, computer software system), and set the relevant parameter range of the detection equipment according to the weld information of the unequal wall thickness pipeline, specifically including: X-ray machine: For workpieces with unequal wall thickness, the penetration of workpieces with unequal wall thickness is usually large. It is necessary to select the energy range of the X-ray machine according to the penetration thickness, material and focal length. In China, the unequal wall thickness welds are usually in the long-distance oil and gas stations. The energy of the X-ray machine should be set in the range of 150-180KeV; Flat panel detector system: It includes a flat panel detector with a built-in A / D converter and accessories (the accessories include a network connection cable, a power adapter, a wireless router, and a computer loaded with flat panel detector control software). The flat panel detector is docked with the accessories through sockets; the number of bits of the A / D converter in the flat panel detector is not less than 12 bits; the flat panel detector has a built-in bad pixel table and a bad pixel correction method, and the dynamic range of the flat panel detector should not be less than 2000:1. Before detection, the detector should be calibrated according to the image calibration method specified by the specific detector system.
[0020] Computer hardware system: The basic configuration of the computer system is determined according to the performance and speed requirements of the X-ray digital imaging component used. It is advisable to be equipped with a memory with a capacity of not less than 4GB, a hard disk with a capacity of not less than 512GB, a high-brightness and high-resolution monitor, as well as a CD burner, a network card, etc. In addition, the monitor should meet the following requirements: the brightness is not less than 250 cd / m², the gray scale is not less than 8 bits, the image display resolution is not less than 1920×1080, and the pixel pitch of the monitor is not higher than 0.3 mm.
[0021] Computer software system: The system software should include basic digital image processing functions such as superposition noise reduction, changing window width and window level, and contrast enhancement; it should have functions for browsing and searching for relevant information of the acquired images; it should include functions such as signal-to-noise ratio measurement, defect marking, dimension measurement, and dimension calibration; it is advisable to have a magnification function of not less than 4 times.
[0022] The voltage selection of the X-ray tube for radiography should meet the requirements of the highest tube voltage allowed by NB / T47013.11, as Figure 2 shown. By adjusting the tube voltage of the X-ray machine, the energy of the X-ray can be changed, so as to ensure an appropriate exposure dose.
[0023] Step 4: Place the single-line image quality indicator and the double-line image quality indicator across the weld. Set the thin-wall side of the base metal of the weld with unequal wall thickness as the starting point for X-ray machine scanning. The X-ray machine emits X-rays to scan the pipeline with unequal wall thickness. The flat panel detector system receives the attenuated signal and presents the signal intensity at different positions in a continuous imaging manner to obtain a signal intensity image, which is the image of the pipeline with unequal wall thickness.
[0024] Among them, 1) The requirements for the radiography method are as follows: When emitting X-rays to scan the pipeline with unequal wall thickness, the single-wall radiography method is preferred, and the double-wall radiography method is only allowed when the single-wall radiography method cannot be implemented.
[0025] When the X-ray machine emits X-rays to scan the pipeline with unequal wall thickness, the scanning speed of the pipeline with unequal wall thickness to be inspected matches the frame rate of image acquisition. At the same time, the main X-ray beam is perpendicularly incident on the pipeline with unequal wall thickness and reaches the effective imaging area of the flat panel detector system.
[0026] The window of the X-ray machine should be placed on the thin-wall side of the base metal of the weld with unequal wall thicknesses to minimize the penetration thickness and improve the sensitivity.
[0027] The static imaging method is used to collect images, and the length of the overlapping area (butt joint part) of the image collection should be not less than 10 mm.
[0028] 2) Process verification of the operation instruction manual: The operation instruction manual should be subjected to process verification before its first application; Verification is carried out using an image quality indicator, a simulated test block or the actual test object; The process verification images should be marked with "GYYZ" or other marks that can be recognized as process verification images.
[0029] 3) Identification of the radiographed film and the image quality indicator Before radiographing the film, marks such as the serial number, welding joint number, position number, and radiographing date should be arranged on the workpiece to be inspected. The marks are generally composed of numbers, pinyin letters, and symbols made of lead or other suitable heavy metals of appropriate sizes, and the marks should not cover the weld and the heat-affected zone.
[0030] The wire-type image quality indicator should be placed at about 1 / 4 of the length to be detected. The metal wire should span across the weld, and the thin wire should be placed on the outside. When performing single-wall single-image, it is placed on the X-ray machine side; when performing double-wall single-image, it is placed on the detector side, and it should be noted in the test report.
[0031] Based on the single-wire-type image quality indicator in the image of the pipeline with unequal wall thicknesses, determine the single-wire number according to the detection technology level; determine the single-wire standard number on the detection standard according to the weld information of the pipeline with unequal wall thicknesses, and compare whether the determined single-wire number meets the single-wire standard number; Based on the double-wire-type image quality indicator in the image of the pipeline with unequal wall thicknesses, calculate the double-wire number according to the detection technology level; determine the double-wire standard number on the detection standard according to the weld information of the pipeline with unequal wall thicknesses, and compare whether the calculated double-wire number meets the double-wire standard number; If the single-wire number meets the single-wire standard number and the double-wire number meets the double-wire standard number, the detection process and the detection equipment meet the standards; otherwise, the detection process does not meet the standards or the detection equipment does not meet the standards. Adjust the detection equipment or the relevant parameter range of the detection equipment, and re-perform step 4.
[0032] Relevant regulations have been made on the image resolution corresponding to different nominal thicknesses or penetration thickness ranges. Among them, the image resolution that should be achieved by the selected detection standard and the AB-class image quality of the detection technology is shown in Table 1, and the image resolution that should be achieved by the detection standard and the B-class image quality of the detection technology is shown in Table 2: Table 1
[0033] Table 2
[0034] The gray scale value of Class AB images should be controlled within 20% - 80% of the full scale, and the gray scale value of Class B images should be controlled within 40% - 80% of the full scale.
[0035] Step 5: Determine the type and length of the defects on the image of the pipe with unequal wall thickness, and grade the welds to be inspected: The grading of the X-ray digital imaging inspection of the welds of the pressure-bearing equipment with unequal wall thickness welded joints shall be carried out in accordance with the provisions of Standard NB / T 47013.2. The grading of the X-ray digital imaging inspection of the welds of the steel pipelines with unequal wall thickness in oil and gas shall be carried out in accordance with the provisions of Standard SY / T 4109 4.18. Example 3 This example is for the welds with unequal wall thickness in the long-distance natural gas station yard.
[0036] Determine the information of the object to be inspected. The thickness of the thick-walled part of the test block is 50 mm, the thickness of the thin-walled part is 30 mm, and the thickness ratio is: 50 / 30 = 1.66 (when the thickness ratio is greater than 1.4, it can be considered as a specimen with a large thickness ratio). The shape of the workpiece is a rectangular test block, and the welding method is GMAW + FCAW-S.
[0037] Determine the inspection standard and inspection technology level. Determine the non-destructive testing standard as SY / T4109-2020, and the inspection technology level as Class AB.
[0038] Determine the set parameters of the inspection equipment and materials according to the wall thickness and shape of the workpiece to be inspected: (1) X-ray machine: The energy of the X-ray machine should be set within the range of 150 - 180 keV; (2) The flat panel detector system includes the flat panel detector and its accessories, etc. The dynamic range should be not less than 2000:1, and the A / D conversion bit number should be not less than 12 bits; The flat panel detector must have a bad pixel table and a bad pixel correction method; Before inspection, the detector should be corrected according to the image correction method specified by the specific detector system.
[0039] (3) Computer hardware system: The basic configuration of the computer system is determined according to the performance and speed requirements of the X-ray digital imaging components used. It is advisable to be equipped with a memory with a capacity of not less than 4 GB, a hard disk with a capacity of not less than 512 GB, a high-brightness and high-resolution monitor, as well as a CD burner, network card, etc. In addition, the monitor should meet the requirements: the brightness is not less than 250 cd / m², the gray scale level is not less than 8 bits, the image display resolution is not less than 1920×1080, and the pixel pitch of the monitor is not higher than 0.3 mm.
[0040] (4)Computer software system: The system software shall include basic digital image processing functions such as superimposed noise reduction, window width and window level change, and contrast enhancement; shall have the functions of browsing and searching for relevant information of the acquired images; shall include functions of signal-to-noise ratio measurement, defect marking, dimension measurement, and dimension calibration; and preferably have a magnification function of not less than 4 times.
[0041] Determine the inspection process parameters (exposure dose, radiographic geometry parameters, material and thickness of the filter plate, relative position between the inspection equipment and the inspection area). The exposure time is selected as 15 s, and the relative position between the inspection equipment and the inspection area is as Figure 3 shown.
[0042] The voltage selection of the X-ray tube for radiography should meet the requirements of the maximum allowable voltage of the X-ray tube in NB / T 47013.11: the current of the X-ray tube for radiography is 6 mA.
[0043] Select the radiographic method, and the radiographic method is the single-wall single-image method. And verify the process of the operation instruction manual. The operation instruction manual should be verified for the process before the first application; verify it with an image quality indicator, a simulated test block or an actual inspection object; the process verification image should be marked with "GYYZ" or other marks that can be recognized as process verification images.
[0044] Radiographic film identification and image quality indicator. It is required that the image quality index is 10, the position of the image quality indicator is on the flat plate side, the model of the image quality indicator is 6FE JB. Before radiographing the film, marks such as serial number, welding joint number, part number, and radiographing date should be arranged on the workpiece to be inspected. The marks are generally composed of numbers, pinyin letters, and symbols made of lead or other suitable heavy metals of appropriate size. The marks should not cover the weld and the heat-affected zone, as Figure 4 shown.
[0045] In this embodiment, the model of the single-line image quality indicator is 6 FE JB, which meets the single-line standard wire number 10 (the actual visible wire is number 11); the model of the double-line image quality indicator is ISO 19232-5, which meets the double-line standard wire number D7. Therefore, the inspection process and inspection equipment meet the standards. The measurement diagrams of the single-line image quality indicator type and the double-line image quality indicator are as Figure 5 shown, the basis for the single wire used is as Figure 6 shown, and the basis for the double wire used is as Figure 7 shown.
[0046] In this example, the base metal thicknesses on both sides of the weld with unequal wall thicknesses are 50 mm and 30 mm respectively, the nominal thickness range is >25 - 55, the image resolution is 2.50 lp / mm, the wire number is D7, the wire diameter is 0.20 mm, and the gray value of the image should be controlled within 20% - 80% of the full scale.
[0047] From Figure 8The following shows the basis for the quality decomposition assessment of strip defects required in 4.18 of SY / T 4109-2020, combined with Figure 8 It can be seen from the requirements of 4.18 in SY / T 4109-2020 that there are 3 strip defects in the weld with unequal wall thickness. Among them, the length of the groove 1-3 defect is 31.6 mm and the width is 4.9 mm, belonging to Grade IV (defect width greater than 2 mm); the length of the groove 1-4 defect is 33.9 mm and the width is 2.1 mm, belonging to Grade IV (defect width greater than 2 mm); the length of the groove 1-5 defect is 39.8 mm and the width is 2.2 mm, belonging to Grade IV (defect width greater than 2 mm).
[0048] Through the above method, the radiographic digital imaging non-destructive testing method for the defects of the weld of the unequal wall thickness pipeline of the present invention solves the problem that the existing equipment cannot perform non-destructive testing on the defects of the unequal wall thickness weld efficiently and accurately; the detection method of the present invention combines the difficulties of unequal wall thickness ray detection, stipulates the parameter selection and precautions during the detection operation of the unequal wall thickness weld, reduces the redundant workload during the detection process, and at the same time ensures the stability of the detection result and the accuracy of the data. The detection method of the present invention can realize the non-destructive testing of the weld of the on-site unequal wall thickness pipeline, and lays a foundation for the efficient and accurate detection of the defects of the unequal wall thickness weld of the steel pipeline.
Claims
1. A radiographic digital imaging non-destructive testing method for weld defects of pipes with unequal wall thicknesses, characterized in that, The implementation is specifically carried out according to the following steps: Step 1: Determine the detection standard and the detection technology level; Step 2: Determine the weld information of the pipeline with unequal wall thickness; Step 3: Select the detection equipment and set the relevant parameter range of the detection equipment according to the weld information of the pipeline with unequal wall thickness; Step 4: Place the single-line image quality indicator and the double-line image quality indicator across the weld, use the detection equipment to collect the image of the pipeline with unequal wall thickness, and judge whether the detection process and the detection equipment meet the standards; Step 5: Grade the quality of the pipeline with unequal wall thickness according to the image of the pipeline with unequal wall thickness.
2. The radiographic digital imaging non-destructive testing method for weld defects of pipes with unequal wall thicknesses according to claim 1, characterized in that The weld information of the pipeline with unequal wall thickness includes the shape of the pipeline with unequal wall thickness, the welding method, the wall thickness of the pipeline, and the weld material.
3. The radiographic digital imaging non-destructive testing method for weld defects of pipes with unequal wall thicknesses according to claim 1, wherein, The detection equipment includes an X-ray machine, a flat panel detector system, a filter plate, a single-line image quality indicator, a double-line image quality indicator, a marking device, a detection tooling, a computer hardware system, a display, and a computer software system.
4. The radiographic digital imaging non-destructive testing method for weld defects of pipes with unequal wall thicknesses according to claim 3, wherein The specific setting of the relevant parameter range of the detection equipment according to the weld information of the pipeline with unequal wall thickness includes: According to the penetration thickness, material, and focal length, select the energy range of the X-ray machine according to the exposure curve graph of the X-ray machine; The flat panel detector system includes a flat panel detector with a built-in A / D converter and accessories. The flat panel detector is docked with the accessories through a socket; the number of bits of the A / D converter in the flat panel detector is not less than 12 bits; the flat panel detector has a built-in bad pixel table and a bad pixel correction method, and the dynamic range of the flat panel detector should not be less than 2000:
1.
5. The radiographic digital imaging non-destructive testing method for weld defects of pipes with unequal wall thickness according to claim 4, characterized in that, The accessories include a network connection cable, a power adapter, a wireless router, and a computer loaded with flat panel detector control software.
6. The radiographic digital imaging non-destructive testing method for weld defects of pipes with unequal wall thicknesses according to claim 3, characterized in that, The specific process of collecting the image of the pipeline with unequal wall thickness in Step 4 is as follows: Place the single-line image quality indicator and the double-line image quality indicator across the weld, set the thin-wall side of the base metal of the weld with unequal wall thickness as the starting point of the X-ray machine scan, the X-ray machine emits X-rays to scan the pipeline with unequal wall thickness, the attenuated signal is received by the flat panel detector system, and the signal intensity at different positions is presented in a continuous imaging manner to obtain a signal intensity image, which is the image of the pipeline with unequal wall thickness.
7. The radiographic digital imaging non-destructive testing method for weld defects of pipes with unequal wall thicknesses according to claim 6, wherein When the X-ray machine emits X-rays to scan the pipeline with unequal wall thickness, the scanning speed of the pipeline with unequal wall thickness to be detected matches the frame rate of image acquisition, and at the same time, the main X-ray beam vertically penetrates the pipeline with unequal wall thickness and reaches the effective imaging area of the flat panel detector system.
8. The radiographic digital imaging non-destructive testing method for weld defects of pipes with unequal wall thicknesses according to claim 3, wherein, The specific process of judging whether the detection process and the detection equipment meet the standards in Step 4 is as follows: According to the single-line image quality indicator in the image of the pipeline with unequal wall thickness, determine the single-line wire number according to the detection technology level; determine the single-line standard wire number on the detection standard according to the weld information of the pipeline with unequal wall thickness, and compare whether the determined single-line wire number meets the single-line standard wire number; According to the double-line image quality indicator in the image of the pipeline with unequal wall thickness, calculate the double-line wire number according to the detection technology level; determine the double-line standard wire number on the detection standard according to the weld information of the pipeline with unequal wall thickness, and compare whether the calculated double-line wire number meets the double-line standard wire number; If the single-line wire number meets the single-line standard wire number and the double-line wire number meets the double-line standard wire number, the detection process and detection equipment meet the standards; otherwise, the detection process does not meet the standards or the detection equipment does not meet the standards. Adjust the detection equipment or the relevant parameter range of the detection equipment, and re-execute step 4.
9. The radiographic digital imaging non-destructive testing method for weld defects of pipes with unequal wall thicknesses according to claim 3, characterized in that The specific process of step 5 is as follows: Determine the defect type and defect length on the image of the unequal wall thickness pipeline to grade the welds to be inspected.