Laser-TIG (Tungsten Inert Gas) electric arc hybrid welding method for aerospace liquid attitude and orbit control titanium alloy storage tank

Abstract

The invention discloses a laser-TIG (Tungsten Inert Gas) electric arc hybrid welding method for a spaceflight liquid attitude and orbit control titanium alloy storage tank, which comprises the following steps of: carrying out a laser-TIG hybrid welding process test by using a flat plate and a profiling piece which are the same as the titanium alloy storage tank in material and thickness in advance; the laser-TIG hybrid welding process parameters of the aerospace liquid attitude and orbit control titanium alloy storage tank with the assembly clearance smaller than or equal to 0.3 mm are obtained; the titanium alloy storage tank is clamped, and it is guaranteed that the assembling gap is smaller than or equal to 0.3 mm; and performing laser-TIG hybrid welding on the titanium alloy storage tank according to the obtained laser-TIG hybrid welding process parameters. The welding method that laser and TIG are combined to act on the same molten pool at the same time is adopted, laser-TIG composite welding is conducted on the spaceflight liquid attitude and orbit control titanium alloy storage tank, and the single laser welding mode and the first single laser welding mode and the second TIG capping welding mode are compared; the method has incomparable advantages in the aspects of mechanical property and welding effect at a welding seam joint, and the production and manufacturing cost can be greatly reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of material engineering welding, and particularly relates to a laser-TIG electric arc composite welding method for a spaceflight liquid attitude and orbit control titanium alloy storage tank. BACKGROUND

[0002] In 2024, the launch activities in the field of global spaceflight transportation were very active, and about 263 launch researches were performed. In the satellite demand end, the medium and large liquid rocket will be the best choice, and the storage tank is one of the most core and important parts in the liquid rocket power system. At present, developed countries such as the United States and Russia are in the leading position in the design and manufacture and test of the storage tank. Due to the adoption of advanced storage tank technology for effective management of liquid propellant in the whole process, the foreign attitude and orbit control power system realizes the requirement of once filling and 15-year long-term storage, which greatly improves the reliability of various spacecrafts in orbit. However, due to the restriction of the design and manufacture technology of the metal diaphragm storage tank, the domestic attitude and orbit control power system cannot meet the development demand, and the technology needs to be broken through.

[0003] The metal diaphragm storage tank is made of titanium alloy, which has the advantages of corrosion resistance, high temperature resistance and light weight, and is widely used. The titanium alloy storage tank can effectively eliminate the shaking of the propellant, but due to the complex structure and numerous parts of the titanium alloy storage tank, the welding quality requirement of the titanium alloy storage tank as a spaceflight product is high, so a reliable welding process method becomes one of the key technical difficulties in the successful manufacture of the titanium alloy storage tank.

[0004] Firstly, titanium alloy starts to oxidize when the temperature exceeds 200 DEG C, which can easily cause problems such as embrittlement and porosity of the welded joint. Secondly, due to the great welding difficulty of the titanium alloy storage tank and the complex working condition, the traditional welding methods such as stick arc welding, gas welding and carbon dioxide shielded welding are not suitable for the welding of titanium and titanium alloy. If manual argon arc welding is used to weld the titanium alloy storage tank, the welding efficiency is low, the smoke and harmful gas generated will cause harm to the workers, the welding quality cannot be guaranteed, there are many welds and the welding position is not ideal, which is a great challenge to the technical level of the welding operator. Whether manual or automatic welding, the weld depth-width ratio is relatively small compared with high-energy beam welding, and the welding deformation is large, which affects the precision of the storage tank or increases the subsequent processing amount. If vacuum electron beam welding is used to weld the titanium alloy storage tank, there are certain limitations: firstly, the joint form and welding position are limited: only straight seams or ring seams can be welded, which is difficult to meet the welding of special-shaped parts and thin-walled parts of the storage tank; secondly, the storage tank has many welds, which needs multiple vacuumizing, multiple fixtures, multiple assembly and multiple welding, and there are problems of low welding efficiency and high cost; in addition, electron beam welding exists radiation, which is harmful to human body. Therefore, to some extent, electron beam welding is difficult to meet the welding requirements of all parts of the titanium alloy storage tank.

[0005] Due to the complex structure of the space liquid attitude and orbit control titanium alloy tank, especially the machining and manufacturing difficulty of the large-size variable-diameter spherical thin-walled part therein, it is difficult to meet the high-precision assembly requirement required by single laser welding or single laser welding and then TIG cover welding, that is, the assembly gap is very small, if the assembly gap is very small, the processing cost will certainly be greatly improved, the processing efficiency will also be greatly reduced, many parts may need to be made on site, the processing efficiency is extremely low, batch production and large-scale production cannot be realized, therefore, a welding process method capable of tolerating a certain assembly gap is needed to efficiently and high-quality complete the welding of the titanium alloy tank. SUMMARY

[0006] In order to solve the problems in the above background art, the present application provides a space liquid attitude and orbit control titanium alloy tank laser-TIG arc composite welding method, which adopts a welding method of laser and TIG composite acting on the same molten pool, does not need to open a groove, does not need to make on site, can tolerate a certain assembly gap, only needs to select appropriate laser-TIG composite welding process parameters according to the size of the assembly gap during welding to weld once, not only the welding quality is guaranteed, but also the welding efficiency is greatly improved, and the vacuum environment is not needed, which is beneficial to realize batch production and large-scale production.

[0007] In order to achieve the above purpose, the present application adopts the following technical scheme:

[0008] The present application provides a space liquid attitude and orbit control titanium alloy tank laser-TIG arc composite welding method, comprising the following steps:

[0009] (1) Pre-expanding laser-TIG composite welding process test by using a flat plate with the same material and thickness as the titanium alloy tank and a profiling piece to obtain the space liquid attitude and orbit control titanium alloy tank laser-TIG composite welding process parameters with an assembly gap of ≤0.3mm;

[0010] (2) Clamping the titanium alloy tank to ensure that the assembly gap is ≤0.3mm;

[0011] (3) Laser-TIG composite welding of the titanium alloy tank according to the laser-TIG composite welding process parameters obtained in step (1).

[0012] The thickness of the titanium alloy tank ranges from 1 to 4mm, and the thickness of each part of the titanium alloy tank is 1mm / 2mm / 3mm / 4mm, the present application is mainly aimed at the titanium alloy tank, therefore, the thickness of the plate for pre-expanding laser-TIG composite welding process test is selected to be 1-4mm.

[0013] The above technical scheme is adopted:

[0014] In this invention, based on the distribution and thickness characteristics of the welding positions in the aerospace liquid attitude and orbit control titanium alloy tank, butt welding tests were conducted on titanium alloy plates with thicknesses of 1mm, 2mm, 2.5mm, 3mm, and 4mm to explore suitable laser-TIG arc hybrid welding process parameters. Considering the high manufacturing cost of the aerospace liquid attitude and orbit control titanium alloy tank, a profiled part with a similar structure to the titanium alloy tank was used to conduct process tests in order to simulate actual working conditions and predict potential problems in the welding of the aerospace liquid attitude and orbit control titanium alloy tank. During the specific welding operation, the bevel of the titanium alloy tank to be welded was first pickled, then rinsed with clean water, and then placed in an oven for drying. After cleaning, it was clamped using tooling fixtures to ensure that the assembly gap of the weld joint was ≤0.3mm. High-purity argon gas was used to protect the front and back of the weld, ensuring that the high-purity argon gas covered the area with a temperature higher than 200℃. After the titanium alloy tank was clamped, the assembly gap of the bevel to be welded was measured using a feeler gauge. The corresponding laser-TIG hybrid welding process was selected according to the three ranges of assembly gap: 0~0.1mm, 0.1mm~0.2mm, and 0.2mm~0.3mm. The laser and TIG eutectic pool were welded simultaneously.

[0015] Further, in step (1), the assembly gap is divided into three intervals: 0-0.1mm, 0.1-0.2mm, and 0.2-0.3mm, and the corresponding laser-TIG composite welding process parameters for each assembly gap interval are obtained.

[0016] Specifically, for assembly gaps in the range of 0–0.1 mm, the process parameters for laser-TIG hybrid welding of titanium alloy tanks are as follows: laser power of 800–3500 W, defocusing amount of +2–+3 mm, laser deflection angle of 8°, welding speed of 1.2–1.4 m / min, wire spacing of 2–3 mm, TIG welding current of 50–80 A, and wire feeding speed of 2–3.5 m / min.

[0017] Specifically, the assembly gap is in the range of 0.1 to 0.2 mm. The process parameters for laser-TIG composite welding of titanium alloy tanks are as follows: laser power of 850 to 3900 W, defocusing amount of +3 to +4 mm, laser deflection angle of 8°, welding speed of 1.2 to 1.5 m / min, wire spacing of 2 to 3 mm, TIG welding current of 60 to 90 A, and wire feeding speed of 2.8 to 4.2 m / min.

[0018] Specifically, for assembly gaps of 0.2–0.3 mm, the process parameters for laser-TIG hybrid welding of titanium alloy tanks are as follows: laser power of 900–3800 W, defocusing amount of +3–+4 mm, laser deflection angle of 8°, welding speed of 1.2–1.5 m / min, wire spacing of 2–3 mm, TIG welding current of 60–100 A, and wire feeding speed of 2.8–4.5 m / min.

[0019] For specific plate thicknesses and assembly gaps, excessively high laser power and insufficient welding speed can lead to burn-through, while excessively low laser power and excessively high welding speed can result in incomplete penetration. Excessive defocusing will result in excessive weld width and reduced weld depth, while insufficient defocusing will result in insufficient weld width and increased weld depth. Excessive welding current will increase weld depth and width, while insufficient welding current will decrease weld depth and width. Excessive wire feed speed will increase filler weight, leading to excessive weld reinforcement, while insufficient wire feed speed will decrease filler weight and cause weld depression. Insufficient wire spacing weakens the interaction between the laser and the arc, reducing weld depth; excessive wire spacing renders the arc ineffective, negatively impacting assembly gaps. In this application, to cover thicknesses ranging from 1mm to 4mm and meet the assembly gap requirements within the aforementioned specific range, the above-mentioned range of process parameters for laser-TIG hybrid welding of titanium alloy tanks was determined through multiple experiments.

[0020] Furthermore, in step (3), before performing laser-TIG composite welding on the titanium alloy tank, laser-TIG composite tack welding is performed first. The process parameters are as follows: tack welding spacing is 40-50mm, tack welding length is 10-15mm, laser power is 700-1000W, defocusing amount is +2-+4mm, laser deflection angle is 8°, welding speed is 1.2-1.5m / min, wire spacing is 2-3mm, TIG welding current is 50-80A, and wire feeding speed is 2-3m / min.

[0021] Furthermore, in step (3), during the laser-TIG composite welding of the titanium alloy tank, high-purity argon gas is used to protect the front and back of the welding area to ensure that the high-purity argon gas covers the area with a temperature higher than 200°C.

[0022] Furthermore, in step (2), before clamping the titanium alloy tank, the bevel of the titanium alloy tank to be welded is pickled in advance, rinsed with clean water after pickling, and then placed in an oven for drying.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) Due to the complex structure of the aerospace liquid attitude and orbit control titanium alloy tank, especially the large-size variable diameter spherical thin-walled component, the processing and manufacturing is extremely difficult, making it difficult to meet the high-precision assembly requirements of single laser welding. Therefore, according to different assembly gaps, the corresponding laser-TIG arc composite welding process parameters are adopted, which can give full play to their respective advantages and better ensure welding quality. Compared with single laser or laser welding followed by TIG cap welding, it can tolerate a considerable assembly gap, greatly enhance the bridging ability of the bevel gap, greatly reduce the precision requirements of the titanium alloy tank bevel processing assembly and weld alignment, significantly expand the engineering application range of laser welding, greatly improve the production efficiency of titanium alloy tanks, reduce production costs, avoid on-site assembly, and realize batch and large-scale production of products.

[0025] (2) Compared with the manual or automatic argon arc welding method for welding titanium alloy tanks, the laser-TIG arc hybrid welding method can obtain a larger weld depth-to-width ratio, eliminate the need for beveling and multi-layer multi-pass welding, and complete the welding in one go. The welding deformation is greatly reduced, the accuracy of the tank is improved, and unnecessary subsequent processing is reduced or eliminated.

[0026] (3) Compared with the method of using vacuum electron beam welding to weld titanium alloy tanks, laser-TIG arc hybrid welding does not require a large vacuum chamber, avoiding multiple vacuuming and multiple clamping welding processes, which greatly improves welding efficiency. At the same time, since laser + TIG hybrid welding does not use expensive high-power lasers, its cost is significantly reduced compared with electron beam welding. In addition, electron beam welding has radiation, which is harmful to the human body, while laser-TIG arc hybrid welding does not have radiation.

[0027] (4) In this invention, before welding the titanium alloy tank for aerospace liquid attitude and orbit control, test pieces and profiling pieces are used to conduct welding tests to simulate the actual working conditions of the tank weld. Only when the welding of the profiling pieces meets the requirements can welding be carried out on the formal sample of the titanium alloy tank. This not only reduces costs, but also allows for the prediction of possible problems during welding. Attached Figure Description

[0028] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0029] Figure 1 This is a flowchart of the laser-TIG arc hybrid welding process for aerospace liquid attitude and orbit control titanium alloy tanks in this invention. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Examples 1-4

[0032] Examples 1-4 are all aerospace liquid attitude and orbit control titanium alloy tanks with assembly gaps in the range of 0 to 0.1 mm. The difference between them is that the thickness of the welded parts is different.

[0033] like Figure 1 As shown, the bevel of the titanium alloy tank for aerospace liquid attitude and orbit control is pickled before welding. After pickling, it is rinsed with clean water and then placed in an oven for drying.

[0034] Then, tooling fixtures are used to clamp the titanium alloy storage tank.

[0035] During the laser-TIG hybrid welding process of titanium alloy tanks, high-purity argon gas is used to protect the front and back of the weld, ensuring that the high-purity argon gas covers the area with a temperature higher than 200°C.

[0036] Before welding, the titanium alloy tank is first subjected to laser-TIG arc hybrid tack welding. The tack welding spacing is 45mm, the tack welding length is 10mm, and the tack welding process parameters are: laser power is 800W, defocusing amount is +3mm, laser deflection angle is 8°, welding speed is 1.2m / min, wire spacing is 2mm, TIG welding current is 50A, and wire feeding speed is 2.5m / min.

[0037] After the tack welding is completed, select a welding wire diameter of 1.2mm, a laser deflection angle of 8°, and use the welding process parameters shown in Table 1 for welding.

[0038] Table 1 Welding process parameters for Examples 1-4

[0039]

[0040] Examples 5-8

[0041] Examples 5-8 are all aerospace liquid attitude and orbit control titanium alloy tanks with assembly gaps in the range of 0.1 to 0.2 mm. The difference between them is that the thickness of the welded parts is different.

[0042] Before welding, the bevel of the titanium alloy tank for aerospace liquid attitude and orbit control is pickled. After pickling, it is rinsed with clean water and then placed in an oven for drying.

[0043] Then, tooling fixtures are used to clamp the titanium alloy storage tank.

[0044] During the laser-TIG hybrid welding process of titanium alloy tanks, high-purity argon gas is used to protect the front and back of the weld, ensuring that the high-purity argon gas covers the area with a temperature higher than 200°C.

[0045] Before welding, the titanium alloy storage tank is first subjected to laser-TIG arc hybrid tack welding. The tack welding spacing is 45mm, the tack welding length is 10mm, and the tack welding process parameters are: laser power is 900W, defocusing amount is +4mm, laser deflection angle is 8°, welding speed is 1.2m / min, wire spacing is 2mm, TIG welding current is 50A, and wire feeding speed is 3m / min.

[0046] After the tack welding is completed, select a welding wire diameter of 1.2mm, a laser deflection angle of 8°, and use the welding process parameters shown in Table 2 for welding.

[0047] Table 2 Welding process parameters for Examples 5-8

[0048]

[0049] Examples 9-12

[0050] Examples 9-12 are all aerospace liquid attitude and orbit control titanium alloy tanks with assembly gaps in the range of 0.2 to 0.3 mm. The difference between them is that the thickness of the welded parts is different.

[0051] Before welding, the bevel of the titanium alloy tank for aerospace liquid attitude and orbit control is pickled. After pickling, it is rinsed with clean water and then placed in an oven for drying.

[0052] Then, tooling fixtures are used to clamp the titanium alloy storage tank.

[0053] During the laser-TIG hybrid welding process of titanium alloy tanks, high-purity argon gas is used to protect the front and back of the weld, ensuring that the high-purity argon gas covers the area with a temperature higher than 200°C.

[0054] Before welding, the titanium alloy tank is first subjected to laser-TIG arc hybrid tack welding. The tack welding spacing is 45mm, the tack welding length is 10mm, and the tack welding process parameters are: laser power is 1000W, defocusing amount is +4mm, laser deflection angle is 8°, welding speed is 1.5m / min, wire spacing is 2mm, TIG welding current is 50A, and wire feeding speed is 2m / min.

[0055] After the tack welding is completed, select a welding wire diameter of 1.2mm, a laser deflection angle of 8°, and use the welding process parameters shown in Table 2 for welding.

[0056] Table 3 Welding process parameters for Examples 9-12

[0057]

[0058] Comparative Examples 1-4

[0059] Comparative Examples 1-4 are comparative test cases of Examples 5-8, and their differences from Examples 5-8 are as follows:

[0060] In Comparative Examples 1-4, no TIG arc was used when welding the titanium alloy tanks. The tack welding of the titanium alloy tanks was carried out using single laser welding with a tack welding spacing of 45 mm and a tack welding length of 10 mm. The tack welding process parameters were: laser power of 900 W, defocusing amount of +4 mm, and laser deflection angle of 8°.

[0061] The other steps and parameter settings in Comparative Examples 1-4 are the same as those in Examples 5-8.

[0062] Comparative Examples 5-8

[0063] Comparative Examples 5-8 are comparative test cases to Examples 9-12, and their differences from Examples 9-12 are as follows:

[0064] In Comparative Examples 5-8, no TIG arc was used when welding the titanium alloy tanks. The tack welding of the titanium alloy tanks was carried out using single laser welding with a tack welding spacing of 40 mm and a tack welding length of 10 mm. The tack welding process parameters were: laser power of 1000 W, defocusing amount of +4 mm, and laser deflection angle of 8°.

[0065] The other steps and parameter settings in Comparative Examples 5-8 are the same as those in Examples 9-12.

[0066] Comparative Examples 9-12

[0067] Comparative Examples 9-12 are comparative test examples of Examples 5-8, and their differences from Examples 5-8 are as follows:

[0068] In Comparative Examples 9-12, the titanium alloy tank was welded using a combination of laser welding followed by TIG arc welding. The laser welding process parameters for Comparative Examples 9-12 are shown in Table 4, and the TIG arc welding process parameters are shown in Table 5. The tack welding of the titanium alloy tank used single-laser welding with a tack weld spacing of 45 mm and a tack weld length of 10 mm. The tack weld process parameters were: laser power of 800 W, defocusing amount of +2 mm, and laser deflection angle of 8°.

[0069] The other steps and parameter settings in Comparative Examples 9-12 are the same as those in Examples 5-8.

[0070] Table 4 Laser welding process parameters for Comparative Examples 9-12

[0071]

[0072] Table 5. TIG arc capping welding process parameters for Comparative Examples 9-12

[0073]

[0074] Comparative Examples 13-16

[0075] Comparative Examples 13-16 are comparative test examples of Examples 9-12, and their differences from Examples 9-12 are as follows:

[0076] In Comparative Examples 13-16, the titanium alloy tank was welded using a combination of laser welding followed by TIG arc welding. The process parameters for laser welding in Comparative Examples 13-16 are shown in Table 6, and the process parameters for TIG arc welding are shown in Table 7. The tack welding of the titanium alloy tank was performed using single-laser welding. The tack welding spacing was 45 mm, the tack welding length was 10 mm, and the tack welding process parameters were: laser power 800 W, defocusing amount +4 mm, and laser deflection angle 8°.

[0077] The other steps and parameter settings in Comparative Examples 13-16 are the same as those in Examples 9-12.

[0078] Table 6 Laser welding process parameters for Comparative Examples 13-16

[0079]

[0080]

[0081] Table 7. TIG arc capping welding process parameters for Comparative Examples 13-16

[0082]

[0083] Performance testing:

[0084] The welded joints of the titanium alloy tanks for aerospace liquid attitude and orbit control in Examples 1-12 and Comparative Examples 1-16 were observed to determine the degree of welding deformation and the surface forming effect of the weld (whether defects such as incomplete penetration, depression, undercut, and sagging occurred at the weld). The mechanical properties of the welded joints of the titanium alloy tanks (with corresponding flat plates for verification) and the base material were also tested. The test results are shown in Tables 8 and 9.

[0085] Table 8 shows the performance test results of the welded joints in each embodiment and comparative example.

[0086]

[0087]

[0088] Table 9 Tensile strength of unwelded base material specimens

[0089]

[0090] As shown in Tables 8 and 9, in Examples 1-12, the tensile strength of the welded joint of the aerospace liquid attitude and orbit control titanium alloy tank (through the corresponding plate side certificate specimen) reached 90% of the tensile strength of the aerospace liquid attitude and orbit control base material specimen, indicating that the laser-TIG arc composite welding achieved the expected effect. The weld surface is relatively beautiful, the edge fusion is good, and no obvious defects such as undercut, depression, or collapse are observed. The weld reinforcement on both sides is normal.

[0091] In Comparative Examples 1-4, since no TIG arc was added and only a single laser was used, compared with Examples 5-8, obvious depressions appeared on the front of the weld, and concavity or sinking appeared on the back of the weld. The thinner the specimen, the more obvious the depressions were.

[0092] In Comparative Examples 5-8, since no TIG arc was added and only a single laser was used, compared with Examples 9-12, the 1 mm thick specimens were almost not fused together. Other specimens showed obvious depressions on the front side of the weld and obvious concavity or sinking on the back side. The thinner the specimen, the more obvious the phenomenon.

[0093] In Comparative Examples 9-12, instead of using a welding method that combines laser and TIG arc on the same molten pool, a welding method of first using a single laser and then using a TIG arc to cover the weld was adopted. Compared with Examples 5-8, the weld front side showed good fusion, while the weld back side showed obvious concavity or sagging, which was more pronounced the thinner the specimen.

[0094] In Comparative Examples 13-16, the welding method that combines laser and TIG arc on the same molten pool was not used. Instead, a welding method of first using a single laser and then using a TIG arc to cover the surface was adopted. Compared with Examples 9-12, the 1mm thick specimens were almost not fused together. Other specimens showed obvious concavity or sagging on the reverse side of the weld, which was more obvious as the specimen thickness was thinner.

[0095] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A laser-TIG arc hybrid welding method for aerospace liquid attitude and orbit control titanium alloy tanks, characterized in that, Includes the following steps: (1) A laser-TIG composite welding process test was conducted in advance using a flat plate and a contoured part with the same material and thickness as the titanium alloy tank to obtain the laser-TIG composite welding process parameters for the aerospace liquid attitude and orbit control titanium alloy tank with an assembly gap of ≤0.3mm. (2) Clamp the titanium alloy tank to ensure that the assembly gap is ≤0.3mm; (3) Perform laser-TIG composite welding on the titanium alloy tank according to the laser-TIG composite welding process parameters obtained in step (1).

2. The laser-TIG arc hybrid welding method for aerospace liquid attitude and orbit control titanium alloy tanks according to claim 1, characterized in that, In step (1), the assembly gap is divided into three intervals: 0-0.1mm, 0.1-0.2mm, and 0.2-0.3mm, and the corresponding laser-TIG composite welding process parameters for each assembly gap interval are obtained.

3. The laser-TIG arc hybrid welding method for aerospace liquid attitude and orbit control titanium alloy tanks according to claim 2, characterized in that, The assembly gap is in the range of 0 to 0.1 mm. The process parameters for laser-TIG hybrid welding of titanium alloy tanks are as follows: laser power of 800 to 3500 W, defocusing amount of +2 to +3 mm, laser deflection angle of 8°, welding speed of 1.2 to 1.4 m / min, wire spacing of 2 to 3 mm, TIG welding current of 50 to 80 A, and wire feeding speed of 2 to 3.5 m / min.

4. The laser-TIG arc hybrid welding method for aerospace liquid attitude and orbit control titanium alloy tanks according to claim 2, characterized in that, The assembly gap is in the range of 0.1 to 0.2 mm. The process parameters for laser-TIG hybrid welding of titanium alloy tanks are as follows: laser power of 850 to 3900 W, defocusing amount of +3 to +4 mm, laser deflection angle of 8°, welding speed of 1.2 to 1.5 m / min, wire spacing of 2 to 3 mm, TIG welding current of 60 to 90 A, and wire feed speed of 2.8 to 4.2 m / min.

5. The laser-TIG arc hybrid welding method for aerospace liquid attitude and orbit control titanium alloy tanks according to claim 2, characterized in that, For assembly gaps of 0.2–0.3 mm, the process parameters for laser-TIG hybrid welding of titanium alloy tanks are as follows: laser power 900–3800 W, defocusing amount +3–+4 mm, laser deflection angle 8°, welding speed 1.2–1.5 m / min, wire spacing 2–3 mm, TIG welding current 60–100 A, and wire feed speed 2.8–4.5 m / min.

6. The laser-TIG arc hybrid welding method for aerospace liquid attitude and orbit control titanium alloy tanks according to claim 1, characterized in that, In step (3), before performing laser-TIG composite welding on the titanium alloy tank, laser-TIG composite tack welding is performed first. The process parameters are as follows: tack welding spacing is 40-50mm, tack welding length is 10-15mm, laser power is 700-1000W, defocusing amount is +2-+4mm, laser deflection angle is 8°, welding speed is 1.2-1.5m / min, filament spacing is 2-3mm, TIG welding current is 50-80A, and wire feeding speed is 2-3m / min.

7. The laser-TIG arc hybrid welding method for aerospace liquid attitude and orbit control titanium alloy tanks according to claim 1, characterized in that, In step (3), during the laser-TIG composite welding of the titanium alloy tank, high-purity argon gas is used to protect the front and back of the welding area to ensure that the high-purity argon gas covers the area with a temperature higher than 200°C.

8. The laser-TIG arc hybrid welding method for aerospace liquid attitude and orbit control titanium alloy tanks according to claim 1, characterized in that, In step (2), before clamping the titanium alloy tank, the bevel of the titanium alloy tank to be welded is pre-pickled, washed with water and dried.

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