Method of diffusion welding of split hollow structural sections

Abstract

The present application relates to the technical field of vacuum diffusion welding, and particularly relates to a diffusion welding method for split hollow structural members. The method comprises the following steps: determining a compression amount of diffusion welding according to the structural characteristics of the split hollow structural member; adjusting the profile size of the split hollow structural member in a reverse deformation manner according to the compression amount; determining the process parameters of vacuum diffusion welding according to the material characteristics of the split hollow structural member; designing and processing a limiting diffusion welding tooling by using a preset deformation amount and a high-temperature deformation difference caused by the difference between the material and the tooling expansion coefficients; and welding the split hollow structural member by using the limiting diffusion welding tooling according to the process parameters. The purpose of the diffusion welding method for the split hollow structural member is to solve the problem of low scale control precision of the hollow structure in the diffusion welding process.

Description

Technical Field

[0001] This invention relates to the field of vacuum diffusion welding technology, and more specifically to a diffusion welding method for split hollow structural components. Background Technology

[0002] Diffusion welding technology can meet the special connection requirements of key components in aerospace products. Therefore, its application in new aerospace products is becoming increasingly widespread. Furthermore, to meet engine weight reduction requirements, components such as the support plates and adjustable guide vanes in aero-engine inlet casings adopt hollow designs. The hollow cavity of the hollow structural component not only reduces weight but also enables functions such as oil intake, oil return, and ventilation within the inlet casing. Changes in the internal dimensions of hollow structural components often affect product performance; therefore, the amount of dimensional deformation during diffusion welding has a significant impact on the internal dimensions of the component. However, for some split hollow structural components, controlling the internal dimensions during diffusion welding remains a challenge.

[0003] Therefore, the inventors have provided a diffusion welding method for split hollow structural components. Summary of the Invention

[0004] (1) Technical problems to be solved

[0005] This invention provides a diffusion welding method for split hollow structural components, which solves the technical problem of low dimensional control accuracy of hollow structures during the diffusion welding process.

[0006] (2) Technical solution

[0007] This invention provides a diffusion welding method for split hollow structural components, comprising the following steps:

[0008] Based on the structural characteristics of the split hollow structural component, determine the compression amount for diffusion welding;

[0009] Based on the compression amount, the surface dimensions of the split hollow structural member are adjusted by reverse deformation;

[0010] Based on the material properties of the split hollow structural component, the process parameters for vacuum diffusion welding are determined;

[0011] By utilizing the preset deformation amount and the high-temperature deformation difference caused by the difference in the expansion coefficients of materials and tooling, a limiting diffusion welding tooling is designed and manufactured.

[0012] According to the process parameters, the split hollow structure is welded using the limiting diffusion welding fixture.

[0013] Furthermore, the method of adjusting the profile dimensions of the split hollow structural component based on the compression amount specifically involves raising both symmetrical half-blade welding surfaces before welding, with the raising amount of each half-blade welding surface being half of the compression amount.

[0014] Furthermore, the compression amount is 1 mm and the elevation amount is 0.5 mm.

[0015] Furthermore, the process of machining the limiting diffusion welding fixture by utilizing the preset deformation amount and the high-temperature deformation difference caused by the difference in the expansion coefficients of the material and the fixture specifically involves:

[0016] The thickness of the limiting diffusion welding fixture is less than the thickness of the split hollow structure.

[0017] Furthermore, the split hollow structural member includes at least one inner cavity, and each inner cavity is a symmetrical structure.

[0018] Furthermore, the material of the split hollow structural component is TC4 titanium alloy.

[0019] Furthermore, the material of the limiting diffusion welding fixture is 1Cr17Ni2.

[0020] Furthermore, after welding the split hollow structure using the limiting diffusion welding fixture according to the process parameters, the process further includes: cutting along a set cross-section of the split hollow structure, removing burrs from the cut, and completing the detection of relevant dimensions and cavity wall thickness.

[0021] (3) Beneficial effects

[0022] In summary, this invention achieves high-precision welding of the welded parts during diffusion welding by designing the structural design of the welding interface allowance area and designing and manufacturing a limiting diffusion welding fixture based on the welding compression amount, and ultimately achieves precise control of the dimensions of the cavity with a hollow cavity structure in the height direction. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic flowchart of a diffusion welding method for a split hollow structural component provided in an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of a split hollow structural component provided in an embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the pre-welding assembly of a split hollow structural component provided in an embodiment of the present invention.

[0027] In the picture:

[0028] 1-First half-blank to be welded; 2-Second half-blank to be welded; 3-Cavity; 4-Welding surface; 5-Limiting diffusion welding fixture. Detailed Implementation

[0029] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present invention by way of example, but should not be used to limit the scope of the present invention. That is, the present invention is not limited to the described embodiments, and any modifications, substitutions and improvements to the parts, components and connection methods are covered without departing from the spirit of the present invention.

[0030] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0031] In the description of this invention, it should be understood that the terms "upper," "lower," "front," "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this invention and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0032] Figure 1 This is a schematic flowchart of a diffusion welding method for a split hollow structural component provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the method may include the following steps:

[0033] S100. Determine the compression amount for diffusion welding based on the structural characteristics of the split hollow structural component.

[0034] S200. Based on the compression amount, the surface dimensions of the split hollow structural component are adjusted by reverse deformation.

[0035] S300. Determine the process parameters for vacuum diffusion welding based on the material properties of the split hollow structural components.

[0036] S400. Design and process a limiting diffusion welding fixture by utilizing the preset deformation amount and the high-temperature deformation difference caused by the difference in the expansion coefficients of the material and the tooling.

[0037] S500. According to the process parameters, the split hollow structure is welded using a limiting diffusion welding fixture.

[0038] In the above implementation, based on the deformation amount of the hollow structure during diffusion welding, the welding surface and cavity of the component are first adjusted in reverse deformation. Through this adjustment, the hollow structure is ensured to meet the design requirements after diffusion welding. By calculating the difference in the expansion coefficients of the material and the tooling, and controlling the height of the tooling limiting device, precise control of the component cavity deformation and the amount of deformation can be achieved, ultimately realizing the application of diffusion welding technology in products with hollow structures.

[0039] As an optional implementation method, the profile dimensions of the split hollow structural component are adjusted by reverse deformation based on the compression amount. Specifically, the welding surfaces of the two symmetrical half-blade components before welding are raised, and the raising amount of each half-blade welding surface is half of the compression amount.

[0040] The compression amount is 1mm and the elevation amount is 0.5mm. Before welding, the overall compression amount of diffusion welding of the part was determined to be 1mm. In order to ensure that the dimensional tolerance of the inner cavity of the component meets the requirements of the design drawings, the welding surfaces of the first half-blank 1 and the second half-blank 2 to be welded were raised. The overall elevation of the welding surface of the half-blank was 0.5mm. The thickness of the half-blank of the part is 10mm and the overall thickness of the component is 20mm.

[0041] As an optional implementation method, the limiting diffusion welding fixture is processed by utilizing the preset deformation amount and the high-temperature deformation difference caused by the difference in the expansion coefficients of the material and the tooling. Specifically, the thickness of the limiting diffusion welding fixture is less than the thickness of the split hollow structure.

[0042] In the above embodiment, the welding temperature of the structural component is 900℃. Due to the different expansion coefficients of the two materials, the thickness of the limiting diffusion welding fixture 5 is set to 18.86mm to control and ensure the blade compression of the structural component. The limiting diffusion welding fixture 5 enables the split hollow structural component and the fixture to achieve high-precision dimensional control under theoretical conditions at the welding temperature. After the split hollow structural component cools down, it can ensure stable deformation and welding quality, as well as the stability of the hollow structure deformation.

[0043] As an optional implementation, the split hollow structural member includes at least one internal cavity, each cavity being a symmetrical structure. Specifically, as... Figure 2 As shown, the split hollow structure includes two symmetrically distributed first half-blanks 1 and second half-blanks 2, as well as a cavity 3 and a welding surface 4 formed after the two half-blanks are joined together. The specific size and shape of the cavity 3 are determined according to actual needs.

[0044] As an optional implementation, the material of the split hollow structure is TC4 titanium alloy. However, there is no specific limitation on the material of the split hollow structure; it is selected based on the specific requirements of the aerospace product components.

[0045] As an optional implementation, the material of the limiting diffusion welding fixture is 1Cr17Ni2. However, the material of the limiting diffusion welding fixture is not specifically limited and is selected based on the diffusion welding process of the split hollow structure.

[0046] As an optional implementation, after welding the split hollow structure using a limiting diffusion welding fixture according to process parameters, the method further includes: step S600, cutting along the set cross section of the split hollow structure, removing burrs from the cut, and completing the detection of relevant dimensions and the wall thickness of the part cavity.

[0047] Specifically, due to structural limitations, the internal dimensions of hollow structural components are difficult to inspect without damage after diffusion welding. To control the accuracy of the internal cavity dimensions, one component from each batch is dissected. For the dissected component, it is cut along a specified cross-section, burrs are removed from the cut, and relevant dimensions and cavity wall thickness are measured. Ultrasonic thickness gauges are not permitted for wall thickness measurement. After testing, the internal cavity dimensional tolerances of the split hollow structural components meet the design requirements.

[0048] Example 1 Diffusion welding process for a certain titanium alloy split hollow structural component

[0049] Material: TC4 titanium alloy, external dimensions 20×80×94; Limiting diffusion welding fixture: material 1Cr17Ni2, external dimensions 18.8×30×50.

[0050] (1) Machining of split hollow structural parts and tooling

[0051] Based on the UG digital model, complete the machining of the half blank of the split hollow structural component; based on the diffusion welding process parameters of the structural component, complete the design and machining of the diffusion welding tooling for the structural component.

[0052] (2) Pre-welding assembly of split hollow structural components

[0053] like Figure 3 As shown, the pre-welding assembly of the split hollow structure is completed. During the diffusion welding process, the limiting diffusion welding fixture 5 can ensure that the final actual deformation of the split hollow structure is consistent with the preset deformation, thus meeting the requirements of subsequent split hollow precision machining.

[0054] (3) Post-weld finishing and dimensional inspection of hollow structural components

[0055] Based on the 2D drawing and UG digital model of the hollow structural component, the outer shape of the ultrasonically tested and qualified hollow structural component is machined. Due to structural limitations, it is difficult to inspect the internal cavity dimensions of the hollow structural component under non-destructive conditions after diffusion welding is completed. To control the accuracy of the internal cavity dimensions, one structural component from each batch is selected for dissection. For the dissected component, it is cut along a specified section, the cut is deburred, and the relevant dimensions and cavity wall thickness are measured. Ultrasonic thickness gauges are not allowed to be used for wall thickness measurement. After testing, the internal cavity dimensional tolerances of the split hollow structural component meet the design requirements.

[0056] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. The present invention is not limited to the specific steps and structures described above and shown in the figures. Furthermore, for the sake of brevity, detailed descriptions of known methods and techniques are omitted here.

[0057] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art without departing from the scope of the invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.

Claims

1. A diffusion welding method for split hollow structural components, characterized in that, The method includes the following steps: Based on the structural characteristics of the split hollow structural component, determine the compression amount for diffusion welding; Based on the compression amount, the surface dimensions of the split hollow structural component are adjusted by reverse deformation. Specifically, the two symmetrical half-blade welding surfaces before welding are raised. The raising amount of each half-blade welding surface is half of the compression amount, where the compression amount is 1 mm and the raising amount is 0.5 mm. Based on the material properties of the split hollow structural component, the process parameters for vacuum diffusion welding are determined; By utilizing the preset deformation amount and the high-temperature deformation difference caused by the difference in the expansion coefficients of the material and the tooling, a limiting diffusion welding tooling is designed and processed. Specifically, the thickness of the limiting diffusion welding tooling is less than the thickness of the split hollow structure. According to the process parameters, the split hollow structure is welded using the limiting diffusion welding fixture.

2. The diffusion welding method for split hollow structural members according to claim 1, characterized in that, The split hollow structural member includes at least one inner cavity, and each inner cavity is a symmetrical structure.

3. The diffusion welding method for split hollow structural members according to claim 1, characterized in that, The material of the split hollow structural component is TC4 titanium alloy.

4. The diffusion welding method for split hollow structural members according to claim 1, characterized in that, The limiting diffusion welding fixture is made of 1Cr17Ni2.

5. The diffusion welding method for split hollow structural members according to claim 1, characterized in that, After welding the split hollow structure using the limiting diffusion welding fixture according to the process parameters, the process further includes: The hollow structural member is cut along a predetermined cross-section, and the cut is used to remove burrs and detect the relevant dimensions and cavity wall thickness.

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