A method for controlling assembly welding precision of a large thin-walled titanium alloy frame

Abstract

The application provides a large thin-wall titanium alloy frame assembly welding precision control method, which comprises the following steps: S1, platform and tooling are made; S2, parts positioning and spot welding are performed; S3, one-time detection and precision adjustment are performed; S4, full welding is performed; and S8, product inspection is performed. Through the large thin-wall titanium alloy frame assembly welding precision control method, high-precision assembly welding of the large thin-wall titanium alloy frame is realized on the basis of greatly reducing the operation difficulty, and the product size deviation is small and the precision is high.

Description

Technical Field

[0001] This invention relates to the field of titanium alloy processing technology, and more specifically, to a method for controlling the welding accuracy of large thin-walled titanium alloy frames. Background Technology

[0002] Titanium alloys possess excellent comprehensive properties such as low density, high specific strength, corrosion resistance, and non-magnetic properties, and have become an important structural material in the field of high-end equipment. With the rapid development of my country's shipbuilding, aviation, and aerospace industries, the demand for high performance and high precision in related supporting equipment has led to the development of titanium alloy castings towards integration, large size, and complexity. In particular, aerospace equipment has an increasing demand for large titanium alloy frame castings, requiring larger dimensions and lighter weight.

[0003] Due to limitations in existing casting furnace equipment size and the difficulty of filling thin-walled titanium alloy molds, the dimensions of large thin-walled titanium alloy frame castings are generally within 3000mm, with a casting wall thickness typically ≥5mm. However, larger and thinner frame structures cannot be directly cast. One feasible research direction is to organize production through component welding; however, this method requires extremely high dimensional accuracy, necessitating strict control of the positional accuracy of each welding step during the assembly stage to avoid affecting yield rates due to significant dimensional deviations. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is to propose a method for controlling the welding accuracy of large thin-walled titanium alloy frames, so as to achieve high-precision welding of large thin-walled titanium alloy frames while greatly reducing the difficulty of operation, and meet the requirements of small product size deviation and high precision.

[0005] To address the aforementioned technical problems, this invention proposes a method for controlling the welding accuracy of large thin-walled titanium alloy frames, comprising the following steps:

[0006] S1: Manufacturing platform and tooling;

[0007] S2: Component positioning and spot welding;

[0008] S3: Single inspection and accuracy adjustment;

[0009] S4: Full soldering;

[0010] S8: Finished product inspection.

[0011] Preferably, step S1 includes the following specific manufacturing steps:

[0012] S11: Fabricate a dedicated large welding platform to ensure that the welding platform is flat and meets the flatness requirements;

[0013] S12: Fabricate welding fixtures, which include at least: support fixtures, fixing fixtures, and anti-deformation fixtures.

[0014] Preferably, after step S12, step S1 further includes the following steps:

[0015] S13: The support fixture is positioned on the welding platform using laser positioning and verified by a theodolite.

[0016] Preferably, the height of the support fixture is greater than 200mm, so that the parts can have welding space in multiple directions after being fixed on it.

[0017] Preferably, step S2 includes the following specific execution steps:

[0018] S21: Select several key components as positioning points, and use their lower end faces as reference surfaces to make corresponding position marks on the welding platform;

[0019] S22: Laser positioning is used, and supporting fixtures are welded at the corresponding marked positions;

[0020] S23: Place the corresponding key components on the support fixture with its positioning center point as the reference, and verify the flatness with a theodolite;

[0021] S24: Using the upper plane of the supporting fixture as a reference, and using a level and height gauge to check, ensure that the error is within 2mm;

[0022] S25: All key components are fixed by spot welding.

[0023] Preferably, in step S25, after each spot weld is completed, the dimensions are checked by chord length to ensure that the dimensional accuracy meets the requirements.

[0024] Preferably, step S3 includes the following specific execution steps:

[0025] S31: Precision inspection, using inspection tools to inspect dimensions and flatness;

[0026] S32: Based on the test results, fine-tune the position of parts with dimensional deviations.

[0027] Preferably, in step S4, a vibration aging apparatus is used to eliminate welding stress.

[0028] Preferably, in step S8, the large thin-walled titanium alloy frame finished product formed by welding is inspected using a 3D scanner.

[0029] Preferably, when the large thin-walled titanium alloy frame is a complex multi-layered structure, after step S4 and before step S8, the control method further includes the following steps:

[0030] S5: Secondary precision inspection based on single-layer full welding;

[0031] S6: Referring to steps S2-S5, complete the full soldering and secondary precision inspection of all other layers one by one;

[0032] S7: Perform overall welding from bottom to top on all qualified layers.

[0033] Compared with existing technologies, the method for controlling the welding accuracy of large thin-walled titanium alloy frames described in this invention has the following advantages:

[0034] 1) While significantly reducing the difficulty of operation, high-precision assembly welding of large thin-walled titanium alloy frames is achieved, meeting the requirements of small product size deviation and high precision;

[0035] 2) The large thin-walled titanium alloy frame is assembled and welded with high precision through the process of “making platform and tooling - component positioning and spot welding - primary inspection and precision adjustment - full welding - finished product inspection”, in order to meet the high dimensional accuracy requirements of component assembly welding. Attached Figure Description

[0036] The accompanying drawings, which constitute a part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention.

[0037] In the picture:

[0038] Figure 1 This is a schematic diagram of the first three-dimensional structure of a large thin-walled titanium alloy frame according to the present invention;

[0039] Figure 2 This is a schematic diagram of the second three-dimensional structure of a large thin-walled titanium alloy frame according to the present invention;

[0040] Figure 3 This is a schematic diagram of a three-dimensional structure with a fully soldered bottom layer according to the present invention;

[0041] Figure 4 for Figure 3 A three-dimensional structural diagram of an external circular I-beam as described in the figure;

[0042] Figure 5 This is a schematic diagram of a three-dimensional structure with a fully welded upper layer according to the present invention. Detailed Implementation

[0043] To make the above-mentioned objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below. It should be understood that the specific embodiments described herein are only some embodiments constituting the present invention, and are only used to explain the present invention, and do not constitute a limitation thereof. Unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0044] See Figure 1-5 As shown, this invention proposes a method for controlling the welding accuracy of large thin-walled titanium alloy frames, comprising the following steps:

[0045] S1: Manufacturing platform and tooling;

[0046] S2: Component positioning and spot welding;

[0047] S3: Single inspection and accuracy adjustment;

[0048] S4: Full soldering;

[0049] S8: Finished product inspection.

[0050] For details, see Figure 1-2 The diagram shown is a three-dimensional structural schematic of a large thin-walled titanium alloy frame. In this invention, when production is organized using component welding, the high dimensional accuracy requirements of component welding can be addressed through a process of "platform and tooling fabrication - component positioning and spot welding - initial inspection and accuracy adjustment - full welding - finished product inspection," thereby achieving high-precision welding of the large thin-walled titanium alloy frame. Thus, while significantly reducing operational difficulty, high-precision welding of the large thin-walled titanium alloy frame is achieved, meeting the requirements of small product dimensional deviations and high precision.

[0051] Preferably, step S1 includes the following specific manufacturing steps:

[0052] S11: Fabricate a dedicated large welding platform to ensure that the welding platform is flat and meets the flatness requirements;

[0053] S12: Fabricate welding fixtures, which include at least: support fixtures, fixing fixtures, and anti-deformation fixtures.

[0054] Specifically, the welding platform can be made of stainless steel, carbon steel, etc., with a flatness generally ≤2mm; the tooling can assist in controlling the welding accuracy of the components in subsequent steps. After step S12, the supporting tooling can be positioned on the welding platform using laser positioning and verified with a theodolite, i.e., step S13; and when the welding platform and supporting tooling are used in a cyclical scenario, step S1 can also include the following calibration steps:

[0055] S14: Regularly calibrate with a level to ensure that the flatness of the welding platform and supporting fixtures is within 2mm.

[0056] As a preferred example of the present invention, the support fixture has a height greater than 200mm, so that the components can be fixed thereon and have welding work space in multiple directions. More specifically, the support fixture may include, for example, welded telescopic legs and a disc.

[0057] Preferably, step S2 includes the following specific execution steps:

[0058] S21: Select several key components as positioning points, and use their lower end faces as reference surfaces to make corresponding position marks on the welding platform;

[0059] S22: Laser positioning is used, and supporting fixtures are welded at the corresponding marked positions;

[0060] S23: Place the corresponding key components on the support fixture with its positioning center point as the reference, and verify the flatness with a theodolite;

[0061] S24: Using the upper plane of the supporting fixture as a reference, and using a level and height gauge to check, ensure that the error is within 2mm;

[0062] S25: All key components are fixed by spot welding.

[0063] Specifically, in step S21, the position markings can be center points and distribution circles, and a center mark can be determined according to the centering principle; in step S22, the height of the support fixture can be different, and can be selected as needed, or the height can be adjusted in step S24; in step S23, positioning center points and extension marks to mark the position of parts can be drawn on the upper plane of some support fixtures, and cross marks can be drawn on some parts; in step S25, the spot welding fixing method can be, for example, argon arc welding, laser welding, etc.

[0064] Preferably, step S3 includes the following specific execution steps:

[0065] S31: Precision inspection, using inspection tools to inspect dimensions and flatness;

[0066] S32: Based on the test results, fine-tune the position of parts with dimensional deviations.

[0067] Specifically, in step S31, the accuracy inspection includes at least dimensional and flatness measurements, and the inspection tool can be, for example, a 3D scanner.

[0068] Preferably, in step S4, a vibration aging apparatus is used to eliminate welding stress.

[0069] Specifically, in step S4, welding can be carried out by symmetrical welding, intermittent welding, etc., until the relevant full welding is completed. During this period, a vibration aging instrument can be used to eliminate welding stress.

[0070] Preferably, in step S8, the large thin-walled titanium alloy frame finished product formed by welding is inspected using a 3D scanner.

[0071] Specifically, the large thin-walled titanium alloy frame may be a relatively simple single-layer structure or a superposition of multiple single-layer structures, i.e. a more complex multi-layer structure. When it is only the former, the assembly and welding of the large thin-walled titanium alloy frame can be completed by step S4. Therefore, the control method described in this invention only needs to include steps S1-S4 before step S8.

[0072] Preferably, when the large thin-walled titanium alloy frame is a complex multi-layered structure, after step S4 and before step S8, the control method further includes the following steps:

[0073] S5: Secondary precision inspection based on single-layer full welding;

[0074] S6: Referring to steps S2-S5, complete the full soldering and secondary precision inspection of all other layers one by one;

[0075] S7: Perform overall welding from bottom to top on all qualified layers.

[0076] Specifically, the secondary precision inspection in step S5 can refer to step S8. The difference is that the inspection object in step S8 is the finished product, even if the finished product may only be a relatively simple single-layer structure; while the inspection object in step S5 must be assembled and welded in step S7 before it can be called a finished product.

[0077] Example 1

[0078] The large titanium alloy frame is welded together, with dimensions of 4000×1000mm and material of TC4.

[0079] I. Production Platform and Tooling

[0080] A dedicated large-scale welding platform needs to be fabricated. The platform must be flat and can be made of materials such as stainless steel or carbon steel. Simultaneously, tooling for support, fixation, and deformation prevention required during the welding process should be fabricated. The support tooling should be longer than 200mm and positioned on the welding platform using laser positioning, verified with a theodolite. The flatness of the welding platform and support tooling should be calibrated with a level before each day's work to ensure that the flatness of the welding platform and support tooling is within 1mm.

[0081] II. Component positioning and spot welding

[0082] First, mark the joint position on the welding platform to weld the support fixture. Mark the joint position on the support fixture and place the joint with the positioning center point and extension direction of the support fixture. After the joint is placed in the positive direction, use a theodolite to determine the flatness.

[0083] Secondly, using the lower end face of the outer I-beam (the upper plane of the supporting fixture) as the reference plane, a level and height gauge are used to check and ensure that the error is within 1mm. The other joints are leveled by adjusting the height of the corresponding supporting fixture according to the reference plane.

[0084] Next, the outer I-beam is fixed to the supporting fixture. Using the lower end face of the outer I-beam (the upper plane of the supporting fixture) as a horizontal reference, three key inner I-beam intermediate joints are selected for laser positioning. The joint positions are then determined by the center mark and the cross marks on the main joints, and spot welding is performed. This layer of structure has a total of 14 pipe joints. The positions of the remaining pipe joints are determined by radiating outwards from the three inner I-beam intermediate joints. After each set of pipe joints is spot welded, the dimensions are checked by the chord length to ensure dimensional accuracy.

[0085] III. Initial Testing and Accuracy Adjustment

[0086] After the components are spot-welded and fixed, a 3D scanner is used to inspect the dimensions, flatness, and other precision. Based on the detailed inspection results, the positions of components with dimensional deviations are fine-tuned.

[0087] IV. Full soldering of the bottom layer

[0088] After adjusting the dimensional accuracy, full welding is performed. Welding can be carried out using methods such as symmetrical welding or intermittent welding. During the welding process, a vibration aging instrument is used to eliminate welding stress.

[0089] V. Finished Product Inspection

[0090] This frame structure is quite complex and requires two layers: a bottom layer and an upper layer, each fully welded separately, before final assembly welding. The complete steps for the upper layer's full welding can be found in steps two through four. Finally, attached... Figure 1-2 A 3D scanner was used to compare and inspect the finished large thin-walled titanium alloy frame after assembly and welding.

[0091] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A method for controlling the welding accuracy of a large thin-walled titanium alloy frame assembly, characterized in that, Includes the following steps: S1: Manufacturing platform and tooling; S2: Component positioning and spot welding; The large, thin-walled titanium alloy frame is a complex multi-layered structure with 14 pipe joints. The positions of the remaining pipe joints are determined by three internal I-beam joints radiating outwards. First, mark the joint position on the welding platform to weld the support fixture. Mark the joint position on the support fixture and place the joint with the positioning center point and extension direction of the support fixture. After the joint is placed in the positive direction, use a theodolite to determine the flatness. Secondly, using the lower end face of the outer circular I-beam as the reference surface, the level and height gauge are used to ensure that the error is within 1mm. The remaining joints are leveled by adjusting the height of the corresponding support fixtures according to the reference surface. Next, fix the outer I-beam on the support fixture. Using the lower end face of the outer I-beam as the horizontal reference, select the three key control points of the inner I-beam intermediate joints, use laser positioning, and determine the joint positions by the center mark and the cross mark on the main joints for spot welding. S3: Single inspection and accuracy adjustment; S4: Full soldering; S8: Finished product inspection; After step S4 and before step S8, the control method further includes the following steps: S5: Secondary precision inspection based on single-layer full welding; S6: Referring to steps S2 and S5, complete the full soldering and secondary precision inspection of all other layers one by one; S7: Perform overall welding from bottom to top on all qualified layers.

2. The method for controlling the welding accuracy of a large thin-walled titanium alloy frame according to claim 1, characterized in that, Step S1 includes the following specific production steps: S11: Fabricate a dedicated large welding platform to ensure that the welding platform is flat and meets the flatness requirements; S12: Fabricate welding fixtures, which include at least: support fixtures, fixing fixtures, and anti-deformation fixtures.

3. The method for controlling the welding accuracy of a large thin-walled titanium alloy frame according to claim 2, characterized in that, Following step S12, step S1 further includes the following steps: S13: The support fixture is positioned on the welding platform using laser positioning and verified by a theodolite.

4. The method for controlling the welding accuracy of a large thin-walled titanium alloy frame according to claim 2, characterized in that, The support fixture is more than 200mm high so that the parts can be fixed on it and have welding space in multiple directions.

5. The method for controlling the welding accuracy of a large thin-walled titanium alloy frame according to claim 1, characterized in that, In step S2, after each spot weld is completed, a set of pipe joints is checked for dimensions by chord length to ensure that the dimensional accuracy meets the requirements.

6. The method for controlling the welding accuracy of a large thin-walled titanium alloy frame according to claim 1, characterized in that, Step S3 includes the following specific execution steps: S31: Precision inspection, using inspection tools to inspect dimensions and flatness; S32: Based on the test results, fine-tune the position of parts with dimensional deviations.

7. The method for controlling the welding accuracy of a large thin-walled titanium alloy frame according to claim 1, characterized in that, In step S4, a vibration aging apparatus is used to eliminate welding stress.

8. The method for controlling the welding accuracy of a large thin-walled titanium alloy frame according to claim 1, characterized in that, In step S8, the large thin-walled titanium alloy frame finished product, which is assembled and welded, is inspected using a 3D scanner.

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