Method suitable for detecting single crystal welding seam
By cutting and processing single crystal weld samples and combining metallographic images with electron backscatter diffraction testing, the problem of inaccurate single crystal weld inspection results was solved, and high-reliability single crystal weld quality assessment was achieved.
Patent Information
- Application Number
- CN202510999056.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-18
- Publication Date
- 2025-10-03
AI Technical Summary
Existing single crystal weld quality inspection methods cannot accurately determine the degree of single crystal, resulting in low reliability of inspection results.
By cutting and processing the sample to be tested, the weld microstructure morphology on the observation surface is determined, and the area of the weld microstructure region is analyzed using metallographic images. Combined with electron backscatter diffraction testing, the single crystal degree of the single crystal weld is accurately determined.
The accuracy and reliability of single crystal weld inspection results are improved, inspection errors are reduced, and the accuracy of quality assessment of single crystal welds is ensured.
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Figure CN120741544A_ABST
Abstract
Description
Technical Field
[0001] The embodiments of the present application relate to the field of welding technology, and in particular to a method suitable for detecting single crystal welds. Background Art
[0002] The statements herein merely provide background information related to the present application and do not necessarily constitute prior art.
[0003] Refractory metal single crystal tubes have excellent high-temperature structural stability and creep resistance, and are widely used in aerospace, laser, nuclear industry and other fields.
[0004] To meet the demands of single-crystal tubing, welding is unavoidable. However, the presence of high-angle grain boundaries in the weld seam can disrupt the single-crystal material's crystallinity, easily inducing cracks and leading to component failure. Therefore, testing the weld quality of single-crystal welds is essential. However, existing methods for determining weld quality often yield limited results and are unreliable. Summary of the Invention
[0005] A brief overview of the present application is provided below to provide a basic understanding of certain aspects of the present application. It should be understood that this overview is not an exhaustive overview of the present application. It is not intended to identify key or important portions of the present application, nor is it intended to limit the scope of the present application. Its purpose is simply to present certain concepts in a simplified form as a prelude to the more detailed description that will be discussed later.
[0006] An embodiment of the present application provides a method suitable for detecting single crystal welds, which includes the following steps: S1, determining a sample to be detected obtained by welding two single crystal samples; S2, cutting the sample to be detected determined in step S1 according to predetermined requirements, and determining the observation surface of the sample to be detected; S3, processing the observation surface determined in step S2, and obtaining the weld tissue morphology on the observation surface; S4, determining the fusion line and the corresponding metallographic image inside it based on the weld tissue morphology obtained in step S3; S5, determining the first area of the target weld tissue area located in the fusion line and the second area of all independent grains located in the fusion line based on the metallographic image determined in step S4; S6, determining the single crystal degree of the single crystal weld based on the first area and the second area determined in step S5, so as to determine the detection result of the single crystal weld based on the single crystal degree.
[0007] The method provided in the embodiments of the present application cuts the sample to be tested according to predetermined requirements to determine the observation surface of the sample to be tested, which is conducive to ensuring the accuracy of the sampling position of the determined weld. By processing the observation surface, the weld tissue morphology on the observation surface can be obtained, and then the corresponding metallographic image is determined based on the weld tissue morphology, and then the detection result of the single crystal weld is determined based on the first area of the target weld tissue area located in the fusion line and the second area of all independent grains located in the fusion line. This method does not simply rely on the metallographic image to directly determine the detection result of the single crystal weld, but can more accurately determine the single crystal degree of the single crystal weld based on the determined first area and second area, and then determine the detection result of the single crystal weld based on the single crystal degree, which is conducive to reducing the error in the process of determining the detection result and improving the reliability of the detection result.
[0008] These and other advantages of the present application will become more apparent through the following detailed description of the preferred embodiments of the present application in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0009] To further illustrate the above and other advantages and features of the present application, the following detailed description of specific embodiments of the present application is provided in conjunction with the accompanying drawings. The accompanying drawings, together with the detailed description below, are incorporated into and form a part of this specification. Elements with the same function and structure are denoted by the same reference numerals. It should be understood that these drawings depict only typical examples of the present application and should not be construed as limiting the scope of the present application.
[0010] Figure 1 is a flow chart of a method for detecting single crystal welds according to an embodiment of the present application;
[0011] Figure 2 is a schematic diagram of a process for determining a sample to be tested according to an embodiment of the present application;
[0012] Figure 3 is a schematic diagram of a process for determining an observation surface of a sample to be detected according to an embodiment of the present application;
[0013] Figure 4 is a schematic diagram of a metallographic image according to an embodiment of the present application.
[0014] It should be noted that the drawings are not necessarily drawn to scale, but are merely shown in a schematic manner that does not affect the reader's understanding.
[0015] Description of reference numerals:
[0016] 11. Single crystal metal tube; 12. Single crystal weld; 13. Sample to be tested; 14. First cutting surface; 15. Second cutting surface; 16. Observation surface; 17. Metallographic image; 171. Fusion line; 172. Target weld microstructure area; 173. Selected weld microstructure area; 174. Independent grains. DETAILED DESCRIPTION
[0017] Exemplary embodiments of the present application will be described below with reference to the accompanying drawings. For the sake of clarity and conciseness, not all features of actual implementations are described in the specification. However, it should be understood that many implementation-specific decisions must be made in the process of developing any such actual implementation in order to achieve the developer's specific goals, such as meeting those constraints related to the system and business, and these constraints may vary depending on the implementation. In addition, it should be understood that although the development work may be very complex and time-consuming, it is a routine task for those skilled in the art who benefit from the content of this application.
[0018] It is also necessary to explain here that, in order to avoid obscuring the present application due to unnecessary details, the accompanying drawings only show the device structure and / or processing steps that are closely related to the solution according to the present application, while other details that are not closely related to the present application are omitted.
[0019] It should be noted that, unless otherwise defined, the technical or scientific terms used in this application should have the common meanings understood by persons having ordinary skills in the field to which this application belongs.
[0020] In the description of the embodiments of the present application, “multiple” means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.
[0021] Currently, the quality of single-crystal welds is often determined by examining the effect of orientation deviation on the microstructure and mechanical properties of the weld. Related techniques include metallographic structure characterization, electron backscatter diffraction (EBSD), room-temperature tensile testing, and hardness testing to determine the weld quality of single-crystal superalloy brazed joints. However, these current methods are unable to determine the degree of single-crystallinity of single-crystal welds, nor can they guarantee the accuracy of the sampling locations of the welds. Consequently, the reliability of the weld quality determination results obtained is low.
[0022] In order to solve the above technical problems, the embodiments of the present application provide a method for detecting single crystal welds. Figure 1 FIG. 1 is a flow chart of a method for detecting single crystal welds according to an embodiment of the present application. Figure 1 As shown, the method may at least include the following steps S1 to S6.
[0023] S1. Determine a sample to be tested obtained by welding two single crystal samples.
[0024] S2. Cut the sample to be tested determined in step S1 according to predetermined requirements to determine the observation surface of the sample to be tested.
[0025] S3. Process the observation surface determined in step S2 to obtain the weld microstructure on the observation surface.
[0026] S4. Determine the fusion line and the corresponding metallographic image inside it based on the weld microstructure obtained in step S3.
[0027] S5. Determine a first area of the target weld microstructure region within the fusion line and a second area of all independent grains within the fusion line based on the metallographic image determined in step S4.
[0028] S6. Determine the single crystal degree of the single crystal weld according to the first area and the second area determined in step S5, so as to determine the inspection result of the single crystal weld based on the single crystal degree.
[0029] The method provided in the embodiments of the present application cuts the sample to be tested according to predetermined requirements to determine the observation surface of the sample to be tested, which is conducive to ensuring the accuracy of the sampling position of the determined weld. By processing the observation surface, the weld tissue morphology on the observation surface can be obtained, and then the corresponding metallographic image is determined based on the weld tissue morphology, and then the detection result of the single crystal weld is determined based on the first area of the target weld tissue area located in the fusion line and the second area of all independent grains located in the fusion line. This method does not simply rely on the metallographic image to directly determine the detection result of the single crystal weld, but can more accurately determine the single crystal degree of the single crystal weld based on the determined first area and second area, and then determine the detection result of the single crystal weld based on the single crystal degree, which is conducive to reducing the error in the process of determining the detection result and improving the reliability of the detection result.
[0030] In some embodiments, in step S1, the single crystal sample may be a single crystal metal tube or a single crystal metal block, etc.
[0031] In some embodiments, Figure 2 is a schematic diagram of a process for determining a sample to be detected according to an embodiment of the present application, such as Figure 2As shown, after directionally welding two single crystal metal tubes 11, a single crystal weld 12 having a certain width can be formed at the joint. In such an embodiment, a circular ring having a certain height can be cut from the welded part along the first cutting surface 14 using wire cutting. During the cutting process, the single crystal weld 12 is ensured to be located in the center area along the axial direction of the circular ring. The cut circular ring is then used as a sample 13 to be tested. The height of the sample 13 to be tested can be within a range of more than 2 mm from the upper and lower edges of the single crystal weld 12.
[0032] In some embodiments, Figure 3 FIG. 1 is a flow chart of determining the observation surface of a sample to be detected according to an embodiment of the present application. Figure 3 As shown, a second cutting plane 15 is determined along a direction perpendicular to the single crystal weld 12, and then the sample 13 to be inspected is cut along the second cutting plane 15 to obtain an observation surface 16 of the sample 13 to be inspected. In such an embodiment, the predetermined requirement is that the direction of the observation surface 16 is perpendicular to the direction of the single crystal weld 12.
[0033] In some embodiments, when welding two single crystal samples, the target weld microstructure region may be the metal region of the single crystal sample that has been heated to a liquid state, and the fusion line may be the solid-liquid boundary between the target weld microstructure region and the unmelted base material. It will be appreciated that during the welding process, the target weld microstructure region is in a liquid state. After the weld is completed and cooled, the target weld microstructure region cools to a solid state, but the fusion line continues to exist after the welding is completed.
[0034] In some embodiments, Figure 4 is a schematic diagram of a metallographic image according to an embodiment of the present application, such as Figure 4 As shown, in step S5, the following steps are included: S51, determining the fusion line 171 in the metallographic image 17; S52, determining the first area of the target weld tissue region 172 based on the fusion line 171, and determining the outline of each independent grain 174 located in the target weld tissue region 172; S53, determining the area of each independent grain 174 based on the outline of the independent grain 174; S54, summing the areas of all independent grains 174 to determine the second area.
[0035] The method provided in the embodiment of the present application determines the first area of the target weld tissue region 172 based on the fusion line 171 in the metallographic image 17, determines the area of each independent grain 174 based on the outline of each independent grain 174 located in the target weld tissue region 172, and then sums the areas of all independent grains 174 to determine the second area. In this way, the outlines of the target weld tissue region 172 and the independent grains 174 are first determined, and then the areas of the target weld tissue region 172 and the independent grains 174 are determined, which is conducive to improving the accuracy of the determined first area and the second area, thereby improving the accuracy of the determined single crystal degree of the single crystal weld 12.
[0036] In some embodiments, the metallographic image 17 can be calibrated with the actual weld structure through the pixel values and scale values of the metallographic image 17 to determine the area of the actual target weld structure area and the total area of all independent grains 174 in the actual target weld structure area based on the area of the target weld structure area 172 in the metallographic image 17 and the total area of all independent grains 174 in the target weld structure area 172.
[0037] In some embodiments, since the outer surface or inner surface of the sample to be tested 13 after welding needs to be processed again, for example, the thickness of the sample to be tested 13 is removed before application, a portion of the selected weld tissue area 173 ( Figure 4 The area within the two white dotted lines shown in the figure) is then determined, and the third area of the selected weld tissue area 173 and the fourth area of all independent grains 174 located in the selected weld tissue area 173 are determined, and the degree of single crystalization of the single crystal weld 12 is determined based on the third area and the fourth area.
[0038] In some embodiments, step S6 includes the following steps: determining a ratio of the second area to the first area based on the first area and the second area determined in step S5; and determining a degree of single crystal weld 12 based on the ratio.
[0039] The method provided in the embodiment of the present application determines the degree of single crystallization of the single crystal weld 12 based on the proportion of the total area of all independent grains 174 in the target weld tissue area 172, which helps to intuitively quantify the degree of single crystallization of the single crystal weld 12.
[0040] In some embodiments, step S3 includes the following steps: S31, grinding the observation surface 16 according to the first predetermined grinding requirement, and then polishing it; S32, chemically corroding the ground and polished observation surface 16 obtained in step S31 to obtain the target weld tissue area 172 on the observation surface 16.
[0041] The method provided in the embodiment of the present application grinds and polishes the observation surface 16, which is conducive to making the observation surface 16 flat, and then chemically corrodes the grinded and polished observation surface 16, which is conducive to improving the clarity of microstructures such as grain boundaries and fusion lines on the observation surface 16, facilitating observation, thereby improving the accuracy of subsequent determination of independent grains 174 on the observation surface 16.
[0042] In some embodiments, the observation surface 16 can be sanded in stages using sandpaper. For example, 600 grit, 800 grit, 1000 grit, 1200 grit, 1500 grit, and 2000 grit sandpaper can be used to sand the observation surface 16 in sequence, ensuring that the scratches on the observation surface 16 are oriented in the same direction after each sanding. In such an embodiment, the first predetermined sanding requirement is that the scratches on the observation surface 16 are oriented in the same direction after sanding.
[0043] In some embodiments, the ground viewing surface 16 may be polished using a polishing machine until the viewing surface 16 is polished to a mirror finish.
[0044] In some embodiments, the single crystal sample is a molybdenum alloy. In step S32, during the chemical etching process, the chemical etching solution is a mixed solution of nitric acid, hydrochloric acid, and hydrofluoric acid. The chemical etching time is 2-4 minutes.
[0045] In the method provided in the embodiment of the present application, a mixed solution of nitric acid, hydrochloric acid and hydrofluoric acid is used as an etching solution to corrode the molybdenum alloy, so that the weld microstructure can be observed more clearly on the observation surface 16 of the corroded molybdenum alloy. The weld microstructure includes the fusion line and the microstructure inside the fusion line.
[0046] In some embodiments, the volume ratio of nitric acid, hydrochloric acid, and hydrofluoric acid in the etching solution is 1:2:2 to ensure the etching effect on the ground and polished observation surface 16.
[0047] In some embodiments, after step S3, the following steps are also included: determining an observation sample based on the sample to be tested 13; performing electron backscatter diffraction analysis on the observation sample to determine the crystal orientation information within the target weld tissue area 172.
[0048] The method provided in the embodiment of the present application can determine the crystal orientation information within the target weld tissue area 172 by performing electron backscatter diffraction analysis on the observed sample. This makes it convenient to observe the microstructure of the central area of the single crystal weld 12 using the backscattered electron diffraction method, thereby ensuring the accuracy of the crystal orientation information obtained within the target weld tissue area 172. At the same time, the crystal orientation information obtained within the target weld tissue area 172 can be easily verified with the observation results of the metallographic image 17, thereby compensating for the deviation in the observation results of the metallographic image 17.
[0049] In some embodiments, the observation sample can be a backscattered electron diffraction test sample. In such an embodiment, the observation sample is placed in a sample chamber of a scanning electron microscope, and then the observation surface 16 is tested using an EBSD probe equipped therewith.
[0050] In some embodiments, the observation sample can be a sample obtained by cutting the sample to be detected 13. During the process of cutting the sample to be detected 13, the observation surface 16 is kept intact.
[0051] In some embodiments, step S5 further includes the following steps: correcting the positions of the independent grains 174 within the target weld tissue area 172 in the metallographic image 17 based on the crystal orientation information; wherein all the independent grains 174 within the target weld tissue area 172 include: independent grains 174 determined directly based on the metallographic image 17, and independent grains 174 determined after correction based on the crystal orientation information.
[0052] The method provided in the embodiment of the present application corrects the position of the independent grains 174 in the target weld tissue area 172 in the metallographic image 17 based on the crystal orientation information, which can ensure that all the independent grains 174 in the target weld tissue area 172 are obtained relatively accurately, and further ensure the accuracy and reliability of the subsequently determined degree of single crystallization.
[0053] In some embodiments, if a single or multiple independent grains 174 exist in the target weld tissue region 172 and extend throughout the thickness direction of the sample 13 to be tested (or observed sample), the degree of single crystallization of the single crystal weld 12 can be determined to be 0%.
[0054] In other embodiments, if the above conditions do not exist, the degree of single crystallization of the single crystal weld 12 can be determined based on the ratio between the second area of all independent grains 174 located in the target weld microstructure region 172 and the first area of the target weld microstructure region 172. In such an embodiment, the degree of single crystallization is equal to 100% minus the ratio of the second area to the first area.
[0055] In some embodiments, a metallographic microscope can be used to capture an image of the observation surface 16. In such an embodiment, the magnification of the metallographic microscope is adjusted to 50 times to obtain the microstructure of the entire target weld tissue region 172, that is, to obtain a metallographic image 17. At the same time, it is determined whether there are single or multiple continuous penetrating grains in the observation surface 16. If there are suspected grains, the image can be magnified to 200 times or 500 times for further observation, and then the location and number of penetrating grains in the target weld tissue region 172 are recorded.
[0056] In some embodiments, determining an observation sample based on the sample to be detected 13 includes the following steps: grinding and then polishing the observation surface 16 according to a second predetermined grinding requirement; electrolyzing and then cleaning the ground and polished observation surface 16 to obtain the observation sample.
[0057] The method provided in the embodiment of the present application performs electrolysis on the ground and polished observation surface 16, which is beneficial for removing interference factors such as distortion of the observation surface 16 and improving the accuracy of subsequent determination of independent grains 174 on the observation surface 16.
[0058] It can be understood that in the embodiments of the present application, the first predetermined grinding requirement and the second predetermined grinding requirement may be the same or different, and the present application does not impose any limitation on this.
[0059] In some embodiments, the observation surface 16 can be sanded in stages using sandpaper. For example, 600 grit, 800 grit, 1000 grit, 1200 grit, 1500 grit, and 2000 grit sandpaper can be used to sand the observation surface 16 in sequence, ensuring that the scratches on the observation surface 16 are oriented in the same direction after each sanding. In such an embodiment, the second predetermined sanding requirement is that the scratches on the observation surface 16 are oriented in the same direction after sanding.
[0060] In other embodiments, sandpaper with other grinding sizes may be used to perform step-by-step grinding on the observation surface 16 .
[0061] In some embodiments, the ground viewing surface 16 may be polished using a polishing machine until the viewing surface 16 is polished to a mirror finish.
[0062] In some embodiments, the single crystal sample is a molybdenum alloy, and the ground and polished observation surface 16 is electrolyzed, including: using dilute sulfuric acid as an electrolyte, performing constant current electrolysis on the ground and polished observation surface 16, and maintaining the electrolysis for a predetermined time.
[0063] The method provided in the embodiment of the present application uses dilute sulfuric acid as the electrolyte and performs constant current electrolysis on the observation surface 16 for a predetermined period of time, which can further ensure the electrolysis effect on the observation surface 16.
[0064] In some embodiments, dilute sulfuric acid with a volume fraction of 20% can be used as an electrolyte to perform constant current electrolysis on the ground and polished observation surface 16, and the current density is maintained at 1A / cm during the constant current electrolysis process. 2 .
[0065] In some embodiments, the predetermined duration may be in the range of 2-3 minutes.
[0066] In some embodiments, the observation sample after electrolysis is cleaned, including: cleaning with chromic acid and deionized solution to remove contamination generated on the surface of the observation sample during the electrolysis process.
[0067] In some embodiments, the test results of the single crystal weld 12 may also include mechanical property test results. In such an embodiment, different national standards may be selected based on the application scenario of the sample 13 to be tested to perform tensile testing on it and obtain mechanical property data of the single crystal weld 12.
[0068] In some embodiments, if the sample to be tested 13 is a non-standard sample, it is necessary to perform mechanical property testing on a base material sample with the same size as the sample to be tested 13 under the same experimental conditions for comparison with the mechanical property data of the single crystal weld 12 in the sample to be tested 13.
[0069] Regarding the embodiments of the present application, it should also be noted that, in the absence of conflict, the embodiments of the present application and the features therein can be combined with each other to obtain new embodiments.
[0070] The above description is only a specific implementation method of the present application, but the protection scope of the present application is not limited thereto. The protection scope of the present application shall be based on the protection scope of the claims.
Claims
1. A method for detecting single crystal welds, characterized in that: The method comprises the following steps: S1. Determine a sample to be tested obtained by welding two single crystal samples; S2. Cutting the sample to be tested determined in step S1 according to predetermined requirements to determine the observation surface of the sample to be tested; S3, processing the observation surface determined in step S2 to obtain the weld microstructure on the observation surface; S4, determining the fusion line and the corresponding metallographic image inside it according to the weld microstructure obtained in step S3; S5. Determine, based on the metallographic image determined in step S4, a first area of a target weld microstructure region within the fusion line and a second area of all independent grains within the fusion line; S6. Determine the single crystal degree of the single crystal weld according to the first area and the second area determined in step S5, so as to determine the inspection result of the single crystal weld based on the single crystal degree.
2. The method according to claim 1, characterized in that In step S5, the following steps are included: S51, determining the fusion line in the metallographic image; S52, determining a first area of the target weld microstructure region according to the fusion line, and determining a contour of each independent grain located in the target weld microstructure region; S53, determining the area of each independent grain according to the outline of the independent grain; S54 , summing the areas of all the independent grains to determine the second area.
3. The method according to claim 2, characterized in that In step S6, the following steps are included: Determine a ratio of the second area to the first area based on the first area and the second area determined in step S5; The degree of single crystallization of the single crystal weld is determined according to the ratio.
4. The method according to claim 1, wherein The S3 step includes the following steps: S31, grinding and then polishing the observation surface according to a first predetermined grinding requirement; S32. Chemically corrode the ground and polished observation surface obtained in step S31 to obtain the weld microstructure on the observation surface.
5. The method according to claim 4, characterized in that The single crystal sample is a molybdenum alloy, In step S32, during the chemical etching process, the etching solution of the chemical etching is a mixed solution of nitric acid, hydrochloric acid and hydrofluoric acid, and the etching time of the chemical etching is 2-4 minutes.
6. The method according to claim 5, characterized in that The volume ratio of the nitric acid, the hydrochloric acid and the hydrofluoric acid in the etching solution is 1:2:
2.
7. The method according to any one of claims 1 to 6, characterized in that After step S3, the following steps are also included: Determining an observation sample according to the sample to be detected; Electron backscatter diffraction analysis is performed on the observed sample to determine crystal orientation information within the weld microstructure.
8. The method according to claim 7, characterized in that In step S5, the following steps are also included: Correcting positions of independent grains located within the fusion line in the metallographic image according to the crystal orientation information; Wherein, all the independent grains located in the fusion line include: the independent grains directly determined based on the metallographic image, and the independent grains determined after correction based on the crystal orientation information.
9. The method according to claim 8, characterized in that The step of determining an observation sample based on the sample to be detected comprises the following steps: grinding and then polishing the observation surface according to a second predetermined grinding requirement; The ground and polished observation surface is electrolyzed and then cleaned to obtain the observation sample.
10. The method according to claim 9, characterized in that The single crystal sample is a molybdenum alloy, The electrolysis of the ground and polished observation surface comprises: Using dilute sulfuric acid as an electrolyte, the ground and polished observation surface is subjected to constant current electrolysis, and the electrolysis is maintained for a predetermined time.
11. The method according to claim 9, characterized in that The observation sample after electrolysis is cleaned, including: cleaning with chromic acid and deionized solution.