Vacuum electron beam welding method for titanium alloy structural part

Abstract

The invention discloses a vacuum electron beam welding method for a titanium alloy structural part, and belongs to the technical field of aero-engine manufacturing. The method comprises the following steps: cleaning stains on the surface of a to-be-welded structural member; an oxidation film on the surface of the to-be-welded structural part is cleaned, and a by-product layer formed when the oxidation film is cleaned is removed in a mechanical mode; residual pollutants generated when the surface of the to-be-welded structural part is cleaned in a mechanical mode are removed, and pre-welding cleaning is completed; when the cleaned structural part to be welded is placed in a vacuum chamber of a vacuum electron beam welding machine to be welded, small-beam preheating is conducted firstly; formal welding is carried out according to pre-optimized welding parameters, and electron beam dynamic deflection is increased in the welding process. The method can reduce air hole defects in welding seams, improve the comprehensive mechanical performance of welding joints, and meet the design requirements of aeroengine component welding joints.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine manufacturing technology and relates to a vacuum electron beam welding method for titanium alloy structural components. Background Technology

[0002] To meet the performance requirements of high thrust-to-weight ratio, new-generation aero-engines are increasingly using novel high-temperature engineering alloys with high specific strength and specific stiffness, such as Ti60, for their hot-section components. Ti60 structural components are often joined using vacuum electron beam welding. Furthermore, due to the complex service environment of hot-section components, vacuum electron beam welded joints must be defect-free or meet stringent welding acceptance standards in terms of the number and type of defects.

[0003] Laboratory studies on vacuum electron beam welding of Ti60 alloy are mostly found in published papers, while research on its engineering applications in industrial equipment is rarely reported. Surveys of published papers reveal that porosity is highly likely to occur in the weld seam during vacuum electron beam welding of Ti60 alloy, and the presence of porosity negatively impacts the overall mechanical properties of the weld joint. In the engineering application research of vacuum electron beam welding of this alloy, it was found that when using conventional and simple process control methods, porosity is indeed prone to occur in the weld seam of Ti60 alloy after welding, and the type, location, size, and number of porosity are relatively random.

[0004] In summary, to advance the research and development of next-generation aviation equipment and ensure the unimpeded application of titanium alloys in high thrust-to-weight ratio aero engines, it is urgent to develop a defect-free vacuum electron beam welding process control method for titanium alloy structural components. This method would effectively eliminate porosity defects in the weld, comprehensively improve welding quality, ensure stable and reliable weld quality, and ensure that the overall mechanical properties of the welded joint strictly meet the design requirements of the aero engine. This would guarantee the safe, stable, and efficient operation of the aero engine in complex service environments. Summary of the Invention

[0005] The purpose of this invention is to provide a vacuum electron beam welding method for titanium alloy structural components, so as to solve the technical problem that porosity is very easy to occur in the weld during vacuum electron beam welding in the prior art, which affects the mechanical properties of the welded joint.

[0006] To achieve the above objectives, the present invention employs the following technical solution: This invention provides a vacuum electron beam welding method for titanium alloy structural components, comprising the following steps: The clean structural components to be welded are placed in the vacuum chamber of the vacuum electron beam welding machine for preheating with a small beam current; Formal welding is performed according to pre-selected welding parameters, with electron beam deflection added during the welding process.

[0007] Furthermore, the clean structural component to be welded is obtained by performing the following cleaning treatment on the structural component to be welded, including: Clean the stains on the surface of the structural components to be welded; Clean the oxide film on the surface of the structural parts to be welded, and remove the by-product layer formed during the oxide film cleaning process by mechanical means; Remove contaminants remaining from mechanical cleaning of the surface of the structural components to be welded, and complete the pre-welding cleaning.

[0008] Furthermore, in the step of cleaning the stains on the surface of the structural component to be welded, the structural component to be welded is cleaned with a silk cloth soaked in acetone until the silk cloth is no longer black.

[0009] Furthermore, in the step of cleaning the oxide film on the surface of the structural component to be welded, laser cleaning or acid pickling is used.

[0010] Furthermore, the laser wavelength for laser cleaning is 1000nm~2000nm, and the power is 50W~100W; the acid solution used in the pickling method is one or a mixture of hydrofluoric acid and nitric acid, wherein the volume concentration of hydrofluoric acid is 2%~3%, and the volume concentration of nitric acid is 30%~35%.

[0011] Furthermore, the machining method is turning or milling; the by-product layer is an oxide layer or a hydrogen-enriched layer.

[0012] Furthermore, in the step of removing contaminants remaining on the surface of the structural component to be welded by mechanical cleaning, the structural component to be welded is cleaned with a silk cloth soaked in acetone until the silk cloth is no longer black.

[0013] Furthermore, the beam current intensity of the small beam preheating is 5% to 15% of the formal welding current, and the number of preheating cycles is 2 to 3.

[0014] Furthermore, the pre-optimization process of the welding parameters includes: optimizing and matching the main process parameters through plate butt welding tests based on the thickness of the joint to be welded and the working distance. The main process parameters include accelerating voltage, welding current, welding speed, and focusing current.

[0015] Furthermore, the deflection amplitude of the electron beam deflection is 0.2 mm to 1.5 mm, and the deflection frequency is 50 Hz to 100 Hz.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a vacuum electron beam welding method for titanium alloy structural components. First, the surface of the structural components to be welded is cleaned to remove contaminants such as oil and sweat. Then, the oxide film on the surface of the welding head and its surrounding area is removed. Simultaneously, a new byproduct layer is generated on the surface of the structural components to be welded through mechanical removal of the oxide film, thus preventing its impact on weld quality. Next, contaminants generated during machining are cleaned again to complete the pre-welding cleaning. Finally, the cleaned structural components are preheated with a small beam current to reduce the temperature gradient during welding and lower thermal stress. Formal welding is performed according to pre-selected welding parameters, and electron beam deflection is added during the welding process to increase the fluidity of the molten pool in the weld, facilitating the effective dissipation of gases generated in the weld pool during electron beam welding of the alloy, thereby eliminating porosity, improving the overall mechanical properties of the welded joint, and meeting the design requirements of welded joints for aero-engine components. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart of a vacuum electron beam welding method for titanium alloy structural components according to an embodiment of the present invention. Detailed Implementation

[0019] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0020] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0021] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0022] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0023] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0024] The present invention will now be described in further detail with reference to the accompanying drawings: 1) Analysis of the causes of porosity in vacuum electron beam welding: There are many and complex reasons why porosity easily occurs in the weld after vacuum electron beam welding of Ti60 alloy. These reasons can be classified into three categories: The composition of the alloy itself is a contributing factor. Ti60 high-temperature titanium alloy contains a variety of high-density, low-density, high-melting-point, and low-melting-point alloying elements. Among them, Nb, Mo, and Ta have relatively high melting points, at 2467℃, 2662℃, and 2996℃ respectively, while C reaches 3550℃. Al and Sn have relatively low melting points, at 660.37℃ and 232℃ respectively, while the melting point of Ti60 alloy is around 1360℃. During vacuum electron beam welding, the high beam power causes instantaneous melting and vaporization of the metal, with the volatilization of low-melting-point components Al and Sn being more severe. If the molten pool has poor fluidity, coupled with the rapid melting and solidification characteristics of vacuum electron beam welding, porosity defects can easily form. Reasons for pre-welding cleaning. The surface of Ti60 alloy is covered with a dense oxide film. The presence of this oxide film increases the tendency for porosity in the weld. Additionally, the presence of contaminants such as oil, moisture, and sweat on the joint surface also makes the weld more prone to porosity. To ensure cleanliness before welding, pre-welding cleaning generally includes pickling and wiping with a cloth soaked in organic solvents such as acetone. Pickling aims to remove the oxide film from the surface of the metal to be welded, while wiping with a cloth soaked in organic solvents such as acetone aims to remove contaminants such as oil, moisture, and sweat. However, improper pickling during the pre-welding pickling process can cause hydrogen enrichment on the surface of the joint to be welded. Since the solubility of hydrogen in the liquid phase is much greater than that in the solid phase, when the molten pool metal cools, pores will precipitate near its fusion line. The general pre-welding cleaning process involves using a wire brush to grind the surface of the joint to be welded after pickling. However, this method cannot effectively prevent hydrogen enrichment on the surface of the joint to be welded from being caused by pickling due to the uneven and inconsistent contact area of ​​the wire brush. The Influence of Welding Process Parameters. For welded joints with a defined thickness and working distance, the main process parameters for vacuum electron beam welding include accelerating voltage, welding current, welding speed, and focusing current. Optimal matching of these parameters is crucial for achieving a good weld. However, welding speed significantly impacts the formation of porosity in vacuum electron beam welds. At lower welding speeds, the volatilization of low-melting-point components such as Al and Sn in the Ti60 alloy weld pool is more severe, leading to porosity as mentioned earlier. Conversely, at higher welding speeds, the cooling rate is faster, and the narrower weld pool in vacuum electron beam welds makes it difficult for pores to evaporate and they remain in the weld as it solidifies.

[0025] 2) Derivation of the approach to porosity control in welds: Based on the above analysis, it can be found that the reasons for porosity during Ti60 vacuum electron beam welding include the material's own composition, as well as pre-weld cleaning and the selection of process parameters during welding. To effectively suppress the tendency of Ti60 alloy to generate porosity during vacuum electron beam welding, consideration should be given to both the selection and setting of pre-weld cleaning methods and steps, and the selection and setting of welding process parameters. Pre-welding cleaning should ensure the removal of oxide film and various surface contaminants from the alloy surface without introducing new contaminants. Alternatively, pre-welding cleaning can be carried out in stages to ensure that any new or potential contaminants generated after the removal of surface oxide film and existing contaminants are also ultimately removed. Welding parameters, such as the matching of acceleration voltage, welding current and welding speed, should ensure complete penetration of the weld joint to form a good weld appearance. At the same time, the welding speed should be reasonably selected and necessary beam oscillation should be increased to maximize the fluidity of the liquid in the weld pool so that any possible gases can be effectively dissipated.

[0026] 3) Implementation of porosity control in the weld: Based on the causes of potential porosity in Ti60 alloy vacuum electron beam welding clarified in step 1) and the approach to porosity control in the weld described in step 2), porosity control in the weld can be achieved through the following steps, the specific implementation methods of which are as follows: Figure 1 As shown, the overall process control steps for defect-free electron beam welding of Ti60 alloy structural parts can be summarized as "cleaning with acetone-soaked cloth → laser cleaning / acid pickling → mechanical removal of oxide / hydrogen-enriching layer → cleaning with acetone-soaked cloth" combined with "optimal matching of main welding parameters + preheating before welding + increasing electron beam deflection in welding parameters". Specifically, it includes the following steps: S1, Clean the stains on the surface of the structural parts to be welded; Soak a cloth in acetone and clean the structural parts to be welded until the cloth is no longer black. The purpose of this step is to clean off the oil, sweat and other contaminants on the surface of the structural parts to be welded, in order to prepare for the next step of removing the oxide film from the joint to be welded. S2, clean the oxide film on the surface of the structural parts to be welded, and remove the by-product layer formed during the oxide film cleaning process by mechanical means; S201, Laser Cleaning / Acid Pickling: Laser cleaning or acid pickling is used to remove the surface oxide film on the surface of the joint to be welded and within a 10mm radius around it. The parameters for laser cleaning or the duration of acid pickling should be optimized and verified through process experiments in advance. The laser wavelength for laser cleaning is 1000~2000nm, and the power is 50W~100W. The acid solution used for acid pickling is one or a mixture of hydrofluoric acid and nitric acid, with a volume concentration of 2%~3% for hydrofluoric acid and 30%~35% for nitric acid.

[0027] S202. Mechanical methods are used to remove the oxide / hydrogen-enriched layer. While laser cleaning removes the surface oxide film, excessive laser irradiation may create a new oxide layer on the alloy surface. During pickling, improper processes may also generate a hydrogen-enriched layer. To remove any potential oxide or hydrogen-enriched layers, machining methods such as turning or milling are used. This process removes a relatively small amount of surface material but effectively prevents any potential oxide or hydrogen-enriched layers from affecting the weld quality.

[0028] S3, removes contaminants remaining from mechanical cleaning of the surface of the structural parts to be welded, completing the pre-welding cleaning; The purpose of cleaning the cloth with acetone is to remove contamination from the surface of the structural parts to be welded due to the machining of S202.

[0029] S4. Place the cleaned structural parts to be welded into the vacuum chamber of the vacuum electron beam welding machine for small beam preheating. Before formal welding, the target structural component to be welded, after pre-welding cleaning, is placed in the vacuum chamber of the vacuum electron beam welding machine. Before formal welding, a larger or even maximum beam current that will not cause the base material to melt at the weld joint should be selected for 2 to 3 preheating cycles. The beam current intensity of the small beam preheating is 5% to 15% of the formal welding current. The purpose of this step is to heat the weld joint as much as possible to remove any residual gas and other liquid contaminants that may remain in the weld joint, and to further ensure the cleanliness of the weld joint.

[0030] S5, perform formal welding according to the pre-selected welding parameters, and add electron beam deflection during the welding process.

[0031] S501, Preliminary matching of formal welding parameters: Based on the thickness of the joint to be welded of the target structural component and the working distance of the electron gun of the vacuum electron beam welder, the main process parameters are optimized through a plate butt test. After welding, the weld quality is evaluated by visual inspection and radiographic testing. The parameters that can ensure good formability of the front and back of the weld and have no or few pores in the weld are selected as the matching of the main process parameters. S502, the formal welding parameters include electron beam dynamic deflection. This process involves increasing the electron beam stirring in the weld pool during the welding of the Ti60 alloy joint. The deflection amplitude of the electron beam dynamic deflection is 0.2 mm to 1.5 mm, and the deflection frequency is 50 Hz to 100 Hz. The purpose of this step is to increase the fluidity of the weld pool, facilitating the effective dissipation of gases generated in the weld pool during electron beam welding of this alloy.

[0032] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0033] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0034] Example 1: S1. Use a silk cloth soaked in acetone to clean the structural parts to be welded until the silk cloth is no longer black.

[0035] S2, laser cleaning is used to remove the surface oxide film on the surface of the head to be welded and within a 10mm radius around the head; the laser wavelength for laser cleaning is 1064nm and the power is 80W; S3, the oxide layer generated by laser cleaning is removed by machining; S4, use a cloth soaked in acetone to clean the contamination on the surface of the structural parts to be welded after the mechanical processing in step S3. S5, Preliminary matching of formal welding parameters: Based on the thickness of the joint to be welded in the target structural component and the working distance of the electron gun relative to the vacuum electron beam welder, the main process parameters are optimized through a plate butt test. S6. Before the formal welding, the structural parts to be welded are placed in the vacuum chamber of the vacuum electron beam welding machine and preheated three times with a small beam current, the beam current intensity being 15% of the formal welding current; S7. Perform formal welding according to the preferred welding parameters, and add electron beam deflection during the welding process. The deflection amplitude is 1.5mm and the deflection frequency is 100Hz.

[0036] Example 2: S1. Use a silk cloth soaked in acetone to clean the structural parts to be welded until the silk cloth is no longer black.

[0037] S2, the surface oxide film on the surface of the joint to be welded and within a 10mm radius around the joint is removed by pickling; the acid solution used for pickling is 2 vol% hydrofluoric acid; S3, the hydrogen-rich layer generated by pickling is removed by milling; S4, use a cloth soaked in acetone to clean the contamination on the surface of the structural parts to be welded after the mechanical processing in step S3. S5, Preliminary matching of formal welding parameters: Based on the thickness of the joint to be welded in the target structural component and the working distance of the electron gun relative to the vacuum electron beam welder, the main process parameters are optimized through a plate butt test. S6. Before the formal welding, the structural parts to be welded are placed in the vacuum chamber of the vacuum electron beam welding machine and preheated three times with a small beam current, the beam current intensity being 10% of the formal welding current; S7. Perform formal welding according to the preferred welding parameters, and add electron beam deflection during the welding process. The deflection amplitude is 1.0 mm and the deflection frequency is 60 Hz.

[0038] Example 3: S1. Use a silk cloth soaked in acetone to clean the structural parts to be welded until the silk cloth is no longer black.

[0039] S2, laser cleaning is used to remove the surface oxide film on the surface of the head to be welded and within a 10mm radius around the head; the laser wavelength for laser cleaning is 1070nm and the power is 100W; S3, the oxide layer generated by laser cleaning is removed by machining; S4, use a cloth soaked in acetone to clean the contamination on the surface of the structural parts to be welded after the mechanical processing in step S3. S5, Preliminary matching of formal welding parameters: Based on the thickness of the joint to be welded in the target structural component and the working distance of the electron gun relative to the vacuum electron beam welder, the main process parameters are optimized through a plate butt test. S6. Before the formal welding, the structural parts to be welded are placed in the vacuum chamber of the vacuum electron beam welding machine and preheated twice with a small beam current, the beam current intensity being 10% of the formal welding current; S7. Perform formal welding according to the preferred welding parameters, and add electron beam deflection during the welding process. The deflection amplitude is 0.5mm and the deflection frequency is 80Hz.

[0040] Example 4: S1. Use a silk cloth soaked in acetone to clean the structural parts to be welded until the silk cloth is no longer black.

[0041] S2, laser cleaning is used to remove the surface oxide film on the surface of the head to be welded and within a 10mm radius around the head; the laser wavelength for laser cleaning is 1080nm and the power is 60W; S3, the oxide layer generated by laser cleaning is removed by milling; S4, use a cloth soaked in acetone to clean the contamination on the surface of the structural parts to be welded after the mechanical processing in step S3. S5, Preliminary matching of formal welding parameters: Based on the thickness of the joint to be welded in the target structural component and the working distance of the electron gun relative to the vacuum electron beam welder, the main process parameters are optimized through a plate butt test. S6. Before the formal welding, the structural parts to be welded are placed in the vacuum chamber of the vacuum electron beam welding machine and preheated three times with a small beam current, the beam current intensity being 5% of the formal welding current; S7. Perform formal welding according to the preferred welding parameters, and add electron beam deflection during the welding process. The deflection amplitude is 1.0 mm and the deflection frequency is 60 Hz.

[0042] Example 5: S1. Use a silk cloth soaked in acetone to clean the structural parts to be welded until the silk cloth is no longer black.

[0043] S2, the surface oxide film on the surface of the joint to be welded and within a 10mm radius around the joint is removed by pickling; the acid solution used for pickling is 30 vol% nitric acid; S3, the hydrogen-rich layer generated by pickling is removed by milling; S4, use a cloth soaked in acetone to clean the contamination on the surface of the structural parts to be welded after the mechanical processing in step S3. S5, Preliminary matching of formal welding parameters: Based on the thickness of the joint to be welded in the target structural component and the working distance of the electron gun relative to the vacuum electron beam welder, the main process parameters are optimized through a plate butt test. S6. Before the formal welding, the structural parts to be welded are placed in the vacuum chamber of the vacuum electron beam welding machine and preheated twice with a small beam current, the beam current intensity being 8% of the formal welding current; S7. Perform formal welding according to the preferred welding parameters, and add electron beam deflection during the welding process. The deflection amplitude is 0.3mm and the deflection frequency is 55Hz.

[0044] Example 6: S1. Use a silk cloth soaked in acetone to clean the structural parts to be welded until the silk cloth is no longer black.

[0045] S2, the surface oxide film on the surface of the joint to be welded and within a 10mm radius around the joint is removed by pickling; the acid solution used for pickling is 35 vol% nitric acid; S3, the hydrogen-rich layer generated by pickling is removed by milling; S4, use a cloth soaked in acetone to clean the contamination on the surface of the structural parts to be welded after the mechanical processing in step S3. S5, Preliminary matching of formal welding parameters: Based on the thickness of the joint to be welded in the target structural component and the working distance of the electron gun relative to the vacuum electron beam welder, the main process parameters are optimized through a plate butt test. S6. Before the formal welding, the structural parts to be welded are placed in the vacuum chamber of the vacuum electron beam welding machine and preheated twice with a small beam current, the beam current intensity being 10% of the formal welding current; S7. Perform formal welding according to the preferred welding parameters, and add electron beam deflection during the welding process. The deflection amplitude is 1.2mm and the deflection frequency is 50Hz.

[0046] Example 7: S1. Use a silk cloth soaked in acetone to clean the structural parts to be welded until the silk cloth is no longer black.

[0047] S2, the surface oxide film on the surface of the joint to be welded and within a 10mm radius around the joint is removed by pickling; the acid solution used for pickling is 32 vol% nitric acid; S3, the hydrogen-rich layer generated by acid washing is removed by machining; S4, use a cloth soaked in acetone to clean the contamination on the surface of the structural parts to be welded after the mechanical processing in step S3. S5, Preliminary matching of formal welding parameters: Based on the thickness of the joint to be welded in the target structural component and the working distance of the electron gun relative to the vacuum electron beam welder, the main process parameters are optimized through a plate butt test. S6. Before the formal welding, the structural parts to be welded are placed in the vacuum chamber of the vacuum electron beam welding machine and preheated three times with a small beam current, the beam current intensity being 5% of the formal welding current; S7. Perform formal welding according to the preferred welding parameters, and add electron beam deflection during the welding process. The deflection amplitude is 0.8mm and the deflection frequency is 65Hz.

[0048] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A vacuum electron beam welding method for titanium alloy structural components, characterized in that, Includes the following steps: The clean structural components to be welded are placed in the vacuum chamber of the vacuum electron beam welding machine for preheating with a small beam current; Formal welding is performed according to pre-selected welding parameters, with electron beam deflection added during the welding process.

2. The vacuum electron beam welding method for titanium alloy structural components according to claim 1, characterized in that, The cleaned structural component to be welded is obtained by performing the following cleaning treatment: Clean the stains on the surface of the structural components to be welded; Clean the oxide film on the surface of the structural parts to be welded, and remove the by-product layer formed during the oxide film cleaning process by mechanical means; Remove contaminants remaining from mechanical cleaning of the surface of the structural components to be welded, and complete the pre-welding cleaning.

3. The vacuum electron beam welding method for titanium alloy structural components according to claim 2, characterized in that, In the step of cleaning the stains on the surface of the structural component to be welded, a silk cloth soaked in acetone is used to clean the structural component to be welded until the silk cloth is no longer black.

4. The vacuum electron beam welding method for titanium alloy structural components according to claim 2, characterized in that, In the step of cleaning the oxide film on the surface of the structural parts to be welded, laser cleaning or acid pickling is used.

5. The vacuum electron beam welding method for titanium alloy structural components according to claim 3, characterized in that, The laser cleaning uses a laser wavelength of 1000nm to 2000nm and a power of 50W to 100W. The acid solution used in the pickling method is one or a mixture of hydrofluoric acid and nitric acid, with the volume concentration of hydrofluoric acid being 2% to 3% and the volume concentration of nitric acid being 30% to 35%.

6. The vacuum electron beam welding method for titanium alloy structural components according to claim 2, characterized in that, The mechanical method is turning or milling; the by-product layer is an oxide layer or a hydrogen-enriched layer.

7. The vacuum electron beam welding method for titanium alloy structural components according to claim 2, characterized in that, In the step of removing contaminants remaining on the surface of the structural component to be welded by mechanical cleaning, the structural component to be welded is cleaned with a silk cloth soaked in acetone until the silk cloth is no longer black.

8. The vacuum electron beam welding method for titanium alloy structural components according to claim 2, characterized in that, The beam current intensity for the low-current preheating is 5% to 15% of the formal welding current, and the preheating is performed 2 to 3 times.

9. The vacuum electron beam welding method for titanium alloy structural components according to claim 2, characterized in that, The pre-optimization process of the welding parameters includes: optimizing and matching the main process parameters through plate butt joint tests based on the thickness of the joint to be welded and the working distance; the main process parameters include acceleration voltage, welding current, welding speed and focusing current.

10. The vacuum electron beam welding method for titanium alloy structural components according to claim 1, characterized in that, The deflection amplitude of the electron beam dynamic deflection is 0.2 mm to 1.5 mm, and the deflection frequency is 50 Hz to 100 Hz.

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