Irregular variable cross-section structure welding seam detection method
By dividing the welded joint into different areas and selecting appropriate radiographic directions and parameters for X-ray inspection, the problem of inspection error in irregularly shaped cross-section structures is solved, and efficient and accurate inspection of welds in irregularly shaped cross-section structures is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-10
- Publication Date
- 2026-03-13
AI Technical Summary
In the existing technology, the X-ray detection beam direction is perpendicular to the direction of the weld joint, which cannot effectively detect the weld joint at the junction of the two cavities of the pressure vessel. In particular, the irregular cross-section structure causes a large variation in the thickness of the weld joint when radiographed, resulting in detection errors.
The weld joint to be inspected is divided into different areas, and different radiographic directions are selected according to the location and structure of different areas. Radiographic parameters of the X-ray machine are used for radiography. The image density and contrast sensitivity of multiple radiographic directions are measured and compared with reference values to determine whether the weld inspection meets the technical requirements.
This avoids detection errors caused by irregular weld cross-sections, improves the accuracy and reliability of weld inspection, and ensures that the internal quality of welded joints meets technical requirements.
Smart Images
Figure CN121656293A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of weld inspection technology, and specifically to a method for inspecting welds in irregularly shaped variable cross-section structures. Background Technology
[0002] Irregularly shaped variable cross-section structures refer to components in the engineering and manufacturing fields whose cross-sectional shape is irregular and varies along the length direction.
[0003] For example, such as Figure 1 As shown, this is a pressure vessel manufactured by our company that will bear significant internal and external loads. During operation, the inner surface will withstand the high temperature and pressure generated by combustion, while the outer surface will withstand aerodynamic loading. Therefore, this pressure vessel has high requirements for strength and internal quality. The pressure vessel is constructed by welding several sections of a double-cavity structure. The junction between the two cavities is an irregularly shaped variable cross-section structure, which is complex and extremely difficult to weld, and is also the area with the highest probability of failure during operation. Defects such as porosity, inclusions, incomplete penetration, lack of fusion, and cracks are prone to occur in this area during welding. Therefore, it is essential to inspect the internal quality of the welded joints in this area. Currently, the main method for inspecting the internal quality of welded joints in pressure vessels is X-ray inspection. During X-ray inspection, to facilitate defect detection, the X-ray beam direction should be perpendicular to the direction of the welded joint.
[0004] However, the product's dual-cavity structure results in a partition obstructing the weld joint below, and the irregular weld cross-section causes significant variations in the thickness of the weld joint when exposed to radiographic light, making it impossible to effectively inspect the weld joint at the junction of the two cavities. Summary of the Invention
[0005] The purpose of this invention is to overcome the above-mentioned technical deficiencies and propose a method for inspecting welds in irregularly shaped variable cross-section structures. This method solves the technical problem that existing technologies cannot effectively inspect welded joints at the junction of two cavities because the X-ray inspection beam direction is perpendicular to the weld joint direction.
[0006] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for inspecting welds in irregularly shaped variable cross-section structures, comprising the following steps: Based on the geometry and structure of the weld joint to be inspected, the weld joint to be inspected is divided into different regions, and different radiographic directions are selected according to the location and structure of different regions. Using tooling, apply a film to the surface of the welded joint to be inspected; Select the X-ray machine's radiographic parameters for different radiographic directions and perform radiography; The film density and contrast sensitivity of images obtained from multiple radiographic directions are measured, and the measured values are compared with reference values to determine whether the weld inspection meets the technical requirements.
[0007] In some embodiments, the weld joint to be inspected includes a first region, a second region, and a third region, wherein the second region and the third region are symmetrically distributed along the center of the first region.
[0008] In some embodiments, the radiographic direction includes a first direction, a second direction, and a third direction, wherein the first direction is set relative to the first region, the second direction is set relative to the second region, and the third direction is set relative to the third region.
[0009] In some embodiments, the X-ray machine along the first direction is a circumferential X-ray machine of type HS-160C, and the X-ray machine along the second or third direction is a directional X-ray machine of type HS-225C.
[0010] In some embodiments, the first direction is perpendicular to the partition direction, and the second or third direction forms an angle with the tangent of the light transmission center and the outer edge surface, the angle being 10° to 15°.
[0011] In some embodiments, the radiographic parameters include focal length, focal spot size, tube voltage, tube current, and exposure time.
[0012] In some embodiments, the radiographic source in the first direction is embedded in the weld joint to be inspected.
[0013] In some embodiments, the second or third direction radiographic source is externally placed on the weld joint to be inspected, and the number of films is two, with the two films respectively connected to the inner wall of the weld joint to be inspected.
[0014] In some embodiments, the two films have different gradients and are simultaneously placed for radiography. When the radiography changes in thickness, the film density in different thickness areas can be satisfied at the same time.
[0015] In some embodiments, the total number of images obtained after radiography is six, and the number of images obtained along the first direction, the second direction, and the third direction are two each.
[0016] Compared with the prior art, the beneficial effects of the method for inspecting welds of irregularly shaped variable cross-section structures provided by the present invention include: firstly, the weld joint to be inspected is divided into different regions according to the geometry and structure of the weld joint to be inspected, and different radiographic directions are selected according to the location and structure of different regions; then, using tooling, film is placed on the surface of the weld joint to be inspected; then, the radiographic parameters of the X-ray machine are selected in different radiographic directions, and radiography is performed; finally, the film density and contrast sensitivity of the images obtained from multiple radiographic directions are measured, and the measured values are compared with reference values to determine whether the weld inspection meets the technical requirements. Compared to existing technologies, this method divides the weld joint to be inspected into different areas and selects different radiographic directions based on the location and structure of each area. After X-ray radiography, the film density and contrast sensitivity of the images obtained from multiple radiographic directions are analyzed against reference values to help determine whether the weld inspection meets the technical requirements. This avoids the detection error caused by the large variation in the radiographic thickness of the weld joint due to the irregular structure of the weld cross-section. It can solve the technical problem in existing technologies where the X-ray detection beam direction is perpendicular to the weld joint direction, making it impossible to effectively inspect the weld joint at the junction of two cavities. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of a pressure vessel provided in an embodiment of the present invention; Figure 2 This is a flowchart of a method for detecting welds in irregularly shaped variable cross-section structures according to an embodiment of the present invention; Figure 3 This is a schematic diagram of an embodiment of the present invention for the inspection of welds in irregularly shaped variable cross-section structures applied to a pressure vessel; Figure 4 yes Figure 3 Enlarged diagram of point A in the middle.
[0018] Explanation of reference numerals in the attached figures: A pressure vessel, 100; Cavity 110; partition 120; welded joint to be inspected 200; first area 210; second area 220; third area 230; radiographic direction 300; first direction 310; second direction 320; third direction 330; film 400; radiation source 500. Detailed Implementation
[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0020] To address the technical problem that using X-ray inspection beams perpendicular to the weld joint direction cannot effectively inspect weld joints at the junction of two cavities, this invention provides a method for inspecting welds in irregularly shaped variable cross-section structures. This method divides the weld joint 200 to be inspected into different regions and selects different radiographic directions 300 based on the location and structure of each region. After X-ray radiography, the film density and contrast sensitivity of the images obtained from multiple radiographic directions 300 are analyzed against reference values to help determine whether the weld inspection meets technical requirements. This avoids detection errors caused by significant variations in the radiographic thickness of the weld joint due to its irregular cross-section.
[0021] Please see Figures 2 to 4 , Figure 2 This is a schematic diagram of a method for inspecting welds in an irregularly shaped variable cross-section structure according to an embodiment of the present invention. The method includes the following steps: selecting a radiographic direction 300; dividing the weld joint 200 to be inspected into different regions based on its geometry and structure; selecting different radiographic directions 300 based on the location and structure of each region; applying a film 400 using a tooling fixture to apply the film 400 to the surface of the weld joint 200; radiography, selecting the radiographic parameters of the X-ray machine at different radiographic directions 300 and performing radiography; and film evaluation, measuring the film density and contrast sensitivity of the images obtained from multiple radiographic directions 300, and comparing the measured values with reference values to determine whether the weld inspection meets the technical requirements.
[0022] In this application, compared with the prior art, by dividing the weld joint 200 to be inspected into different regions and selecting different radiographic directions 300 according to the location and structure of different regions, after X-ray radiography, the film density and contrast sensitivity of the images obtained from multiple radiographic directions 300 are analyzed with reference values to help determine whether the weld inspection meets the technical requirements. This avoids the detection error caused by the large variation in the radiographic thickness of the weld joint due to the irregular structure of the weld cross section. It can solve the technical problem in the prior art that the method of using the X-ray detection beam direction perpendicular to the weld joint direction cannot effectively detect the weld joint at the junction of two cavities.
[0023] Furthermore, here as Figure 1As shown, a pressure vessel 100 manufactured by our company includes a cavity 110 and a partition 120. This pressure vessel 100 will bear significant internal and external loads, and during operation, its inner surface must withstand the high temperature and pressure generated during combustion, while its outer surface must withstand aerodynamic loading. Therefore, this pressure vessel has high requirements for product strength and internal quality. The pressure vessel is constructed by welding several sections of a double-cavity structure. The junction of the two cavities is an irregularly shaped variable cross-section structure, which is complex and extremely difficult to weld, and is also the area with the highest probability of failure during operation. Defects such as porosity, inclusions, incomplete penetration, lack of fusion, and cracks are prone to occur in this area during welding. Therefore, it is necessary to inspect the internal quality of the welded joint. However, the double-cavity structure of this product results in the partition 120 obstructing the welded joint, and the irregular welded cross-section causes significant variations in the thickness of the welded joint under radiographic light, making it impossible to effectively inspect the welded joint at the junction of the two cavities.
[0024] Furthermore, using an X-ray machine to examine the weld is a routine method in weld inspection and is a standard procedure known to those skilled in the art, so it will not be elaborated upon here.
[0025] In some embodiments, during the patching process, an elastic structure corresponding to the internal cavity 110 of the product is used to apply the film 400. This allows the film 400 to be stably abutted against the inner wall of the area to be tested. The elastic structure is an inverted "U" shape, and its two ends can generate elastic restoring forces that move closer or further apart. The elastic structure has a clamping groove on the inner wall of the area to be tested to accommodate the film 400. The user first fixes the film 400 in the clamping groove, then squeezes the elastic structure to deform and shrink it. The shrunken elastic structure is then inserted into the cavity 110 of the product. Finally, after the pressure is released, the elastic structure automatically returns to its original shape and presses the film 400 firmly against the inner wall of the area to be tested. Further details are omitted here.
[0026] In this embodiment, as Figure 4 As shown, in step 300, the welded joint to be inspected 200 includes a first region 210, a second region 220 and a third region 230, and the second region 220 and the third region 230 are symmetrically distributed along the center of the first region 210.
[0027] By dividing the weld joint 200 to be inspected into a first region 210, a second region 220 and a third region 230, the weld joint 200 to be inspected can be inspected from three different radiographic directions 300, which can improve the accuracy of the inspection results.
[0028] Furthermore, the second region 220 and the third region 230 are respectively located on both sides of the first region 210 and are symmetrically distributed along the center of the first region 210, which can simplify the setting of radiography parameters and improve the operability and accuracy of the detection method.
[0029] In one embodiment, such as Figure 4 As shown, in step 300, the radiographic direction 300 includes a first direction 310, a second direction 320 and a third direction 330. The first direction 310 is set relative to the first region 210, the second direction 320 is set relative to the second region 220, and the third direction 330 is set relative to the third region 230.
[0030] The first direction 310 is set relative to the first region 210, the second direction 320 is set relative to the second region 220, and the third direction 330 is set relative to the third region 230, wherein the second direction 320 and the third direction 330 are symmetrically distributed.
[0031] In one embodiment, during the radiography step, the X-ray machine along the first direction 310 is a circumferential X-ray machine of type HS-160C, and the X-ray machine along the second direction 320 or the third direction 330 is a directional X-ray machine of type HS-225C.
[0032] In this application, a circumferential X-ray machine of model HS-160C is used to irradiate the first region 210, and a directional X-ray machine of model HS-225C is used to irradiate the second region 220 or the third region 230.
[0033] Furthermore, the HS-160C circumferential X-ray machine and the HS-225C directional X-ray machine mentioned here are common and readily available equipment on the market, and are conventional setups known to those skilled in the art, so they will not be described in detail here.
[0034] In one embodiment, the first direction 310 is perpendicular to the partition 120, and the second direction 320 or the third direction 330 forms an angle α with the tangent of the light transmission center and the outer edge surface, the size of the angle α being 10° to 15°.
[0035] The first direction 310 is a horizontal direction perpendicular to the partition 120. The second direction 320 and the third direction 330 are symmetrically distributed along the partition 120, and the second direction 320 or the third direction 330 forms an angle α of 10° to 15° with the tangent of the center of illumination and the outer edge.
[0036] In some embodiments, the X-ray source 500 that generates radiopaque light along the first direction 310 is located inside the cavity housing of this product. The end face of the cavity housing is provided with an opening that communicates with its interior. The user can extend the X-ray source 500 of the HS-160C circumferential X-ray machine into the interior of the cavity housing and set it relative to the first region 210. This will not be described in detail here.
[0037] Furthermore, such as Figure 3 As shown, the radiation source 500 that generates transmitted light along the second direction 320 or the third direction 330 is located outside the cavity housing of this product and is respectively positioned relative to the second region 220 or the third region 230.
[0038] In one embodiment, the radiography parameters in the radiography step include focal length, focal spot size, tube voltage, tube current, and exposure time.
[0039] By rationally selecting radiographic parameters such as focal length, focal spot size, tube voltage, tube current, and exposure time, the accuracy of testing can be improved, meeting the requirements of standardized production.
[0040] In one embodiment, the transmission parameters of the first direction 310 are: focal length 150mm, focal spot size 0.4mm×4mm, tube voltage 78kV, tube current 8mA, and exposure time 2min.
[0041] By setting standardized radiography parameters, the accuracy of detection can be improved.
[0042] In one embodiment, the transmission parameters of the second direction 320 or the third direction 330 are: focal length 900mm, focal spot size 0.4mm×0.4mm, tube voltage 85kV, tube current 4mA, and exposure time 3min.
[0043] By setting standardized radiography parameters, the accuracy of detection can be improved.
[0044] In one embodiment, during the film evaluation step, the film density in the radiopaque area is 2.0 to 3.2, and the image quality value is W14.
[0045] When evaluating the negatives, the film density and contrast sensitivity were measured. The film density in the radiopaque area was 2.0 to 3.2, and the image quality value was W14, which meets the requirements of GJB1187A.
[0046] Furthermore, GJB1187A here is the national standard for weld inspection, which is a standard setting known to those skilled in the art and will not be elaborated further here.
[0047] In one embodiment, in the film evaluation step, the total number of images obtained after radiography is six, and the number of images obtained along the first direction 310, the second direction 320 and the third direction 330 are two each.
[0048] Using two images combined for three different directions improves the accuracy of the assessment.
[0049] Furthermore, the six radiographs obtained were evaluated. If no defects were found in the four radiographs taken along the second direction 320 and the third direction 330, but a crack defect was found in the radiograph taken along the first direction 310, the welded joint did not meet the technical requirements.
[0050] In addition, in some embodiments, two films with different gradients are selected and placed simultaneously for radiography, so that the blackness of the film in different thickness areas can be satisfied at the same time when the radiography area varies greatly in thickness.
[0051] Furthermore, the film is evaluated by measuring the film's blackness and contrast sensitivity to ensure that the blackness and contrast sensitivity of the film within the radiographic area meet the standard requirements; the six radiographic images are evaluated, and the quality of the welded joint in the area is comprehensively assessed based on the images of the six films.
[0052] To better understand this invention, the following is combined with... Figures 1 to 4 The technical solution of the present invention will be described in detail below: First, based on the geometry and structure of the weld joint 200 to be inspected, the weld joint 200 is divided into different regions. Different radiographic directions 300 are selected according to the location and structure of each region. Next, using a fixture, film 400 is placed on the surface of the weld joint 200. Then, the radiographic parameters of the X-ray machine are selected at different radiographic directions 300, and radiography is performed. Finally, the film density and contrast sensitivity of the images obtained from multiple radiographic directions 300 are measured, and the measured values are compared with reference values to determine whether the weld inspection meets the technical requirements. Compared with existing technologies, by dividing the weld joint 200 to be inspected into different regions and selecting different radiographic directions 300 according to the location and structure of each region, and analyzing the film density and contrast sensitivity of the images obtained from multiple radiographic directions 300 after X-ray radiography, the determination of whether the weld inspection meets the technical requirements is aided. This avoids the detection errors caused by the large variations in the radiographic thickness of the weld joint due to its irregular weld cross-section.
[0053] The specific testing steps for this application are as follows: The radiographic direction 300 is selected. Based on the geometry and structure of the inspected part, the welded joint is divided into three regions (first region 210, second region 220, and third region 230). Then, the radiographic direction is determined according to the location and structure of the three regions, and radiographic direction is determined from the first direction 310, the second direction 320, and the third direction 330. Specifically, the first direction 310 and the second direction 320 are radiographically transmitted using an HS-225C directional X-ray machine, forming an angle α of 10° to 15° with the tangent of the radiographic center and the outer edge. The third direction 330 is radiographically transmitted using an HS-160C circumferential X-ray machine. For patch application, apply film 400 to the surface of the welded joint. Two different grades of film 400, Kodak AA400 and Kodak MX125, are applied simultaneously for radiography. Among them, the transmission parameters for direction 1 are: focal length 900mm, focal spot size 0.4mm×0.4mm, tube voltage 85kV, tube current 4mA, and exposure time 3min; Among them, the transmission parameters for direction 2 are: focal length 900mm, focal spot size 0.4mm×0.4mm, tube voltage 85kV, tube current 4mA, and exposure time 3min; Among them, the transmission parameters for direction 3 are: focal length 150mm, focal spot size 0.4mm×4mm, tube voltage 78kV, tube current 8mA, and exposure time 2min. The film was evaluated, and its blackness and contrast sensitivity were measured. The blackness of the film within the radiographic area was 2.0~3.2, and the image quality value was W14, meeting the requirements of GJB1187A. The six radiographic images were evaluated. No defects were found in the four images corresponding to the second direction 320 and the third direction 330. One crack defect was found in the image corresponding to the first direction 310, indicating that the welded joint did not meet the technical requirements.
[0054] This application solves the technical problem in the prior art that the welding joint at the junction of two cavities cannot be effectively inspected because the X-ray detection beam direction is perpendicular to the welding joint direction.
[0055] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.
Claims
1. A method for inspecting welds in irregularly shaped variable cross-section structures, characterized in that, Includes the following steps: Based on the geometry and structure of the weld joint to be inspected, the weld joint to be inspected is divided into different regions, and different radiographic directions are selected according to the location and structure of different regions. Using tooling, apply a film to the surface of the welded joint to be inspected; Select the X-ray machine's radiographic parameters for different radiographic directions and perform radiography; The film density and contrast sensitivity of images obtained from multiple radiographic directions are measured, and the measured values are compared with reference values to determine whether the weld inspection meets the technical requirements.
2. The method for inspecting welds in irregularly shaped variable cross-section structures according to claim 1, characterized in that, The weld joint to be inspected includes a first region, a second region, and a third region, with the second and third regions symmetrically distributed along the center of the first region.
3. The method for inspecting welds in irregularly shaped variable cross-section structures according to claim 2, characterized in that, The radiographic direction includes a first direction, a second direction, and a third direction. The first direction is set relative to the first region, the second direction is set relative to the second region, and the third direction is set relative to the third region.
4. The method for inspecting welds in irregularly shaped variable cross-section structures according to claim 3, characterized in that, The X-ray machine along the first direction is a circumferential X-ray machine of type HS-160C, and the X-ray machine along the second or third direction is a directional X-ray machine of type HS-225C.
5. The method for inspecting welds in irregularly shaped variable cross-section structures according to claim 4, characterized in that, The first direction is perpendicular to the direction of the partition, and the second or third direction forms an angle with the tangent of the center of illumination and the outer edge, the angle being 10° to 15°.
6. The method for inspecting welds in irregularly shaped variable cross-section structures according to claim 3, characterized in that, The radiographic parameters include focal length, focal spot size, tube voltage, tube current, and exposure time.
7. The method for inspecting welds in irregularly shaped variable cross-section structures according to claim 3, characterized in that, The light source in the first direction is built into the weld joint to be inspected.
8. The method for inspecting welds in irregularly shaped variable cross-section structures according to claim 3, characterized in that, The second or third direction radiographic source is placed externally on the weld joint to be inspected, and there are two films, which are respectively connected to the inner wall of the weld joint to be inspected.
9. The method for inspecting welds in irregularly shaped variable cross-section structures according to claim 8, characterized in that, The two films have different gradients and are placed simultaneously for radiography. When the radiography changes in thickness, the film density in different thickness areas can be satisfied at the same time.
10. The method for inspecting welds in irregularly shaped variable cross-section structures according to claim 3, characterized in that, The total number of images obtained after radiography is six, with two images obtained along the first direction, two along the second direction, and two along the third direction.