A friction stir welding method for a curved aluminium alloy profile

Abstract

The application discloses a kind of arc aluminum alloy profile's friction stir welding welding method, comprising: the shape data of profile is collected, matching friction stir welding welding tooling;Profile is placed in the friction stir welding welding tooling after adaptation, and space posture is calibrated;Profile is multidimensional collaborative fixed based on the fixed component of the friction stir welding welding tooling;Profile is respectively carried out first round friction stir welding and second round friction stir welding based on the stir head of the friction stir welding welding tooling;It is cooled to handle to be welded, and the shaped arc aluminum alloy profile component is obtained.The friction stir welding welding method for arc aluminum alloy profile provided by the application has the advantages of fast welding speed, high welding strength, low welding environment requirement and low welding cost, effectively improves the quality of shaped product, meets the comprehensive demand of high-end equipment on shaping precision, production efficiency and environmental protection.

Description

Technical Field

[0001] This invention relates to the field of welding technology, and in particular to a friction stir welding method for curved aluminum alloy profiles. Background Technology

[0002] With the rapid development of transportation technology, the rail vehicle manufacturing industry is continuously moving towards lightweighting, high strength, and high efficiency. Aluminum alloys, due to their excellent specific strength and corrosion resistance, are widely used in curved structural components such as sidewalls and roofs, becoming a key component in rail vehicle parts. Welding, as a critical connection process, directly affects the vehicle's safety, durability, and production costs. Currently, aluminum alloy welding technology is mainly based on arc welding. However, with increasing demands for welding speed, quality, and environmental friendliness, traditional welding methods are no longer sufficient to meet the needs of high-end equipment manufacturing. This is especially true for curved profiles, whose complex geometry makes them prone to deformation and defects during welding. The industry urgently needs innovative processes to achieve high-precision, high-efficiency forming connections.

[0003] In the existing technology, the welding technology for curved aluminum alloy profiles mainly adopts melting inert gas welding (MIG welding). However, its welding speed can usually only reach 1100mm / min, and the strength of the aluminum alloy decreases too much after welding, resulting in poor weld appearance and quality stability. At the same time, due to its reliance on welding wire and shielding gas, it has problems such as high requirements for welding environment, high welding cost, and large environmental pollution from arc light and noise. Although it can achieve basic connection, it cannot meet the comprehensive requirements of high-end equipment for forming accuracy, production efficiency and environmental protection. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art. This invention provides a friction stir welding method for curved aluminum alloy profiles, which has the advantages of fast welding speed, high welding strength, low welding environment requirements and low welding cost, effectively improving the quality of the formed products and meeting the comprehensive requirements of high-end equipment for forming accuracy, production efficiency and environmental protection.

[0005] This invention provides a friction stir welding method for curved aluminum alloy profiles, the welding method comprising:

[0006] S101. Collect the shape data of the curved aluminum alloy profile to be welded, and match the friction stir welding fixture based on the collected shape data.

[0007] S102. Place the curved aluminum alloy profile to be welded in the adapted friction stir welding fixture, and calibrate the spatial orientation of the curved aluminum alloy profile to be welded.

[0008] S103. The curved aluminum alloy profile to be welded is fixed in a multi-dimensional coordinated manner based on the fixing components of the friction stir welding fixture.

[0009] S104. Based on the stirring head of the friction stir welding fixture, the curved aluminum alloy profile to be welded is subjected to a first round of friction stir welding and a second round of friction stir welding.

[0010] S105. After completing two rounds of friction stir welding, the welded curved aluminum alloy profile is cooled to obtain the formed curved aluminum alloy profile assembly.

[0011] Furthermore, in step S101, the shape data of the curved aluminum alloy profile to be welded is collected, and the friction stir welding fixture is matched based on the collected shape data, including:

[0012] The arc contour data, cross-sectional dimension data, and length data of the curved aluminum alloy profile to be welded are accurately collected, and suitable friction stir welding fixtures are selected based on the collected arc contour data, cross-sectional dimension data, and length data.

[0013] Furthermore, in step S102, placing the curved aluminum alloy profile to be welded in the adapted friction stir welding fixture and calibrating the spatial orientation of the curved aluminum alloy profile to be welded includes:

[0014] The curved aluminum alloy profile to be welded is placed in the friction stir welding fixture according to the preset placement method. The joint of the profile is aligned by a laser alignment component or a vision alignment component. The lateral, longitudinal and circumferential positions of the profile are adjusted based on the alignment detection results.

[0015] Furthermore, in step S103, the multi-dimensional coordinated fixing of the curved aluminum alloy profile to be welded based on the fixing components of the friction stir welding fixture includes:

[0016] Analyze and extract the side profile data of the curved aluminum alloy profile to be welded;

[0017] Select a suitable clamping block based on the side profile data, and assemble the clamping block onto the side clamping arm of the friction stir welding fixture.

[0018] Adjust the extension and retraction of the movable side arm of the side clamping arm relative to the fixed side arm so that the contact surface of the clamping block fits against the side of the profile;

[0019] The side clamping arm and clamping block apply clamping force to the side of the profile.

[0020] Furthermore, in step S103, the multi-dimensional coordinated fixing of the curved aluminum alloy profile to be welded based on the fixing components of the friction stir welding fixture also includes:

[0021] Analyze and extract the top surface contour data of the curved aluminum alloy profile to be welded;

[0022] The spacing of the clamping arm heads on the vertical clamping arm of the friction stir welding fixture is adjusted according to the top surface contour data, so that the clamping arm heads are evenly spaced along the extension direction of the lower surface of the vertical clamping arm, and each clamping arm head can correspond to the effective clamping area of ​​the top surface of the profile.

[0023] Select a clamping arm head whose contact surface matches the top surface contour of the profile, and adjust the extension and retraction of the clamping arm head so that the contact surface of the clamping arm head can fit against the top surface of the profile.

[0024] The vertical clamping arm and the clamping arm head apply a clamping force to the top surface of the profile.

[0025] Furthermore, in step S103, the multi-dimensional coordinated fixing of the curved aluminum alloy profile to be welded based on the fixing components of the friction stir welding fixture also includes:

[0026] Analyze and extract the bottom contour data of the curved aluminum alloy profile to be welded;

[0027] The spacing of the support pads of the friction stir welding fixture is adjusted according to the bottom contour data so that the support pads are evenly spaced along the weld extension direction of the profile, and each support pad can correspond to the effective support area of ​​the bottom surface of the profile.

[0028] Select a support pad whose contact surface matches the bottom contour of the profile, and adjust the height of the support pad so that the contact surface of the support pad can fit against the bottom surface of the profile.

[0029] The support plate applies a supporting force to the bottom surface of the profile.

[0030] Furthermore, the method also includes: after step S103, the spacing of the curved aluminum alloy profile to be welded is detected by a laser alignment component or a vision alignment component; if the spacing detection result does not meet the standard, the process returns to step S102.

[0031] The spacing detection of the curved aluminum alloy profile to be welded using a laser alignment component or a vision alignment component includes:

[0032] The butt joint spacing d1 at the joint of the profile is inspected, and the acceptable value range for the butt joint spacing d1 is: d1 < 0.5 mm;

[0033] The upper and lower overlap spacing d2 at the joint of the profile is tested. The acceptable value range for the upper and lower overlap spacing d2 is: d2 < 0.4 mm.

[0034] The misalignment distance d3 at the joint of the profile is tested. The acceptable range for the misalignment distance d3 is: d3 < 0.3 mm.

[0035] Furthermore, in step S104, the stirring head is a single-shoulder stirring head, the stirring head is made of H14 carbon tool steel, the needle length of the stirring head matches the wall thickness of the profile, and the shoulder diameter of the stirring head matches the weld width and weld depth of the profile.

[0036] Furthermore, in the first round of friction stir welding in step S104, the curved aluminum alloy profile to be welded is placed in the friction stir welding fixture in a reverse assembly manner, and the reverse weld of the curved aluminum alloy profile to be welded is welded based on the stirring head of the friction stir welding fixture.

[0037] In the second round of friction stir welding in step S104, the curved aluminum alloy profile to be welded is placed in the friction stir welding fixture in a front-side assembly manner, and the front weld of the curved aluminum alloy profile to be welded is performed based on the stirring head of the friction stir welding fixture.

[0038] Furthermore, in step S104, the weld seam of the central profile of the curved aluminum alloy profile to be welded is welded first, and then the weld seams of the profiles extending from the center to both sides are welded in sequence.

[0039] This invention provides a friction stir welding method for curved aluminum alloy profiles. By collecting shape data regarding the curvature profile, cross-sectional dimensions, and length of the curved aluminum alloy profile to be welded, matching it with specialized friction stir welding fixtures, and performing precise spatial orientation calibration, multi-dimensional collaborative fixing, and multi-stage welding processes, the method effectively controls joint quality, achieving high-precision, high-strength curved profile connections. This method solves the problems of displacement deformation and joint misalignment that easily occur during the welding of curved aluminum alloy profiles in traditional welding methods, improving welding accuracy and quality. It avoids the defects of traditional welding methods, such as material strength attenuation, stringent environmental requirements, and environmental pollution. It boasts advantages such as fast welding speed, high welding strength, low welding environmental requirements, and low welding cost, effectively improving the quality of the formed products and meeting the comprehensive requirements of high-end equipment for forming accuracy, production efficiency, and environmental protection. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art 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.

[0041] Figure 1 This is a flowchart of the friction stir welding method for curved aluminum alloy profiles in Embodiment 1 of the present invention;

[0042] Figure 2 This is a schematic diagram of the butt joint assembly structure of the curved aluminum alloy profile in Embodiment 1 of the present invention;

[0043] Figure 3 This is a reverse assembly structure diagram of the curved aluminum alloy profile in the welding fixture in Embodiment 1 of the present invention;

[0044] Figure 4 This is a front assembly structure diagram of the curved aluminum alloy profile in the welding fixture in Embodiment 1 of the present invention;

[0045] Figure 5 This is a flowchart illustrating the process of fixing the profile based on the side clamping assembly in Embodiment 1 of the present invention;

[0046] Figure 6 This is a flowchart illustrating the process of fixing the profile using a vertical clamping assembly in Embodiment 1 of the present invention;

[0047] Figure 7 This is a flowchart of fixing the profile based on the support component in Embodiment 1 of the present invention;

[0048] Figure 8 yes Figure 2 Enlarged schematic diagram of point a in the middle.

[0049] In the figure: curved aluminum alloy profile 1, first profile 11, second profile 12, third profile 13, fourth profile 14, fifth profile 15, first butt joint structure 21, second butt joint structure 22, joint 23, overlap 24, boss 25, first side clamping arm 31, second side clamping arm 32, clamping block 33, first vertical clamping arm 41, second vertical clamping arm 42, clamping arm head 43, support pad 51. Detailed Implementation

[0050] 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.

[0051] In this invention, it should be understood that terms such as “comprising” or “having” are intended to indicate the presence of features, figures, steps, behaviors, components, portions or combinations thereof disclosed in this specification, and are not intended to exclude the possibility that one or more other features, figures, steps, behaviors, components, portions or combinations thereof are present or added.

[0052] It should also be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0053] Example 1

[0054] In the field of rail vehicle manufacturing, aluminum alloy profiles, due to their complex geometry, are prone to stress concentration and thermal deformation during welding. This leads to defects such as gaps, uneven overlaps, and misalignments at the joints, thus affecting the stability of welding quality. This problem stems from the mismatch between traditional welding processes and the curved surface characteristics of the profiles, resulting in uneven heat input distribution, a significant decrease in local strength of the material, and limited welding efficiency, making it impossible to meet the dimensional accuracy and structural integrity requirements of lightweight components.

[0055] For example, in the production process of rail vehicle side wall panels, when using molten inert gas welding to connect curved aluminum alloy profiles, the profile's curvature profile is not well-suited to the tooling. The welding thermal cycle causes asymmetrical stress, resulting in slight displacement of the profile in the lateral and circumferential directions. The joints are not tightly fitted, and porosity and lack of fusion defects appear in the weld area. Subsequent assembly requires repeated adjustments to correct the deformation, increasing the complexity of the process.

[0056] If the above problems are not effectively resolved, the residual stress in the welded components will continue to accumulate, which may lead to cold cracks and post-deformation, reducing the durability and safety of the vehicle structure. At the same time, arc light and noise pollution in the welding environment will be difficult to control, restricting the improvement of production efficiency and increasing the risk of quality fluctuations in the manufacturing process.

[0057] In response, Embodiment 1 of the present invention provides a friction stir welding method for curved aluminum alloy profiles, the welding method comprising:

[0058] S101. Collect the shape data of the curved aluminum alloy profile to be welded, and match the friction stir welding fixture based on the collected shape data.

[0059] S102. Place the curved aluminum alloy profile to be welded in the adapted friction stir welding fixture, and calibrate the spatial orientation of the curved aluminum alloy profile to be welded.

[0060] S103. The curved aluminum alloy profile to be welded is fixed in a multi-dimensional coordinated manner based on the fixing components of the friction stir welding fixture.

[0061] S104. Based on the stirring head of the friction stir welding fixture, the curved aluminum alloy profile to be welded is subjected to a first round of friction stir welding and a second round of friction stir welding.

[0062] S105. After completing two rounds of friction stir welding, the welded curved aluminum alloy profile is cooled to obtain the formed curved aluminum alloy profile assembly.

[0063] Specifically, the friction stir welding method for curved aluminum alloy profiles in this embodiment operates through a systematic process to achieve high-precision and high-efficiency welding. First, the shape data of the curved aluminum alloy profile to be welded is collected, and the friction stir welding fixture is matched based on the collected shape data. This ensures precise geometric adaptation between the fixture and the profile, eliminating stress concentration and welding deformation risks caused by geometric mismatch at the source. Customized support is specifically implemented for the curved surface characteristics of the profile. Further, the profile is placed in the adapted fixture, and its spatial orientation is calibrated. By dynamically adjusting the lateral, longitudinal, and circumferential positions, a tight fit at the joint is ensured, effectively suppressing defects such as gaps, uneven overlaps, and misalignments. The fixture's fixing components provide multi-dimensional collaborative fixation of the profile, implementing all-round constraints and evenly distributing clamping force to prevent local warping caused by welding heat input, particularly suitable for the asymmetric stress requirements of curved profiles. Friction stir welding (FSW) is performed on the profiles using a stirring head, with the reverse side welded first, followed by the front side weld. This staged fusion allows for gradual stress release, reducing residual deformation. Simultaneously, FSW avoids material melting, improving connection strength and surface quality. After both rounds of welding, the welded profiles are cooled to smooth temperature gradients, prevent cold cracking and post-deformation, and ensure dimensional accuracy and structural integrity of the components.

[0064] In one optional implementation of this embodiment, such as Figure 1 As shown, Figure 1The flowchart of the friction stir welding method for curved aluminum alloy profiles according to Embodiment 1 of the present invention is shown, including the following steps:

[0065] S101. Collect the shape data of the curved aluminum alloy profile to be welded, and match the friction stir welding fixture based on the collected shape data.

[0066] In one optional implementation of this embodiment, the curvature profile data, cross-sectional dimension data, and length data of the curved aluminum alloy profile to be welded are accurately collected, and a suitable friction stir welding fixture is selected based on the collected curvature profile data, cross-sectional dimension data, and length data.

[0067] Specifically, based on a three-dimensional laser scanning device, the arc contour data, cross-sectional dimension data, and length data of the curved aluminum alloy profile to be welded are accurately collected, and a suitable friction stir welding fixture is selected based on the collected arc contour data, cross-sectional dimension data, and length data.

[0068] Furthermore, the curvature profile data refers to the bending shape parameters of the profile in three-dimensional space, which aims to accurately reflect the spatial curvature changes of the profile; the cross-sectional dimension data refers to the geometric parameters of the profile's cross-section, which aims to accurately obtain the thickness and width information of the profile; and the length data refers to the dimensional parameters of the profile along the extension direction, which aims to fully describe the overall dimensions of the profile.

[0069] This is because traditional welding methods do not include a mechanism for collecting shape data for curved profiles. This is because the geometry of curved aluminum alloy profiles is complex and easily deformed. If only general shape data is collected, as is the case with flat aluminum alloy profiles, it may lead to inaccuracies in key parameters such as curvature profile, cross-sectional dimensions, and length. This would result in the matching tooling not being able to fully adapt to the actual three-dimensional shape of the profile, which in turn would cause defects such as profile positioning deviation, joint misalignment, and welding deformation in subsequent fixing and welding stages, affecting the final component's forming accuracy and structural strength.

[0070] Therefore, in this embodiment, a three-dimensional laser scanning acquisition method is considered to scan the curved aluminum alloy profile with welding, accurately acquire its curvature contour data, cross-sectional dimension data, and length data, obtain the complete three-dimensional geometric information of the profile, and then select suitable friction stir welding fixtures based on these acquired data to avoid positioning deviations caused by parameter mismatch, thereby providing a reliable geometric basis for subsequent multi-dimensional collaborative fixing and high-precision welding.

[0071] In one optional implementation of this embodiment, after the shape data of the profile is collected, a suitable friction stir welding fixture is selected based on the collected shape data, including curvature contour data, cross-sectional dimension data and length data, so that the selected fixture can be matched with the curved aluminum alloy profile to be welded and complete the subsequent welding work.

[0072] The above technical solution ensures that the welding fixture for friction stir welding is precisely matched with the actual geometric shape of the curved aluminum alloy profile, effectively avoiding problems such as profile positioning deviation, joint misalignment and welding deformation caused by inaccurate fixture adaptation, thereby improving the forming accuracy and structural strength of the welded components.

[0073] S102. Place the curved aluminum alloy profile to be welded in the adapted friction stir welding fixture, and calibrate the spatial orientation of the curved aluminum alloy profile to be welded.

[0074] In one optional implementation of this embodiment, the curved aluminum alloy profile to be welded is placed in a friction stir welding fixture based on a preset placement method.

[0075] Specifically, the preset placement method refers to the initial positioning strategy preset based on the curvature contour data of the profile. It can be achieved by setting the positioning reference point by matching the three-dimensional model generated based on the shape data of the profile, or by combining the cross-sectional size data and length data to generate the support path planning. This can reduce initial deviations and lay the foundation for subsequent high-precision calibration.

[0076] In one optional implementation of this embodiment, after the curved aluminum alloy profile to be welded is placed in the friction stir welding fixture, the joint of the profile is aligned by a laser alignment component or a vision alignment component, and the lateral position, longitudinal position and circumferential position of the profile are adjusted based on the alignment detection results.

[0077] Specifically, ideally, after placing the curved aluminum alloy profile to be welded in the friction stir welding fixture, its placement should be completely consistent with the preset placement method. However, errors are unavoidable in actual operation. Therefore, it is necessary to perform alignment detection on the joint of the placed profile. Alignment detection refers to the process of quantitatively measuring the geometric features of the profile joint. This can be achieved using contour matching algorithms or feature point cloud comparison technology. The data collected by the above methods can be obtained through laser alignment components or vision alignment components. These two components can be implemented using infrared laser scanning, combined with a reflective target or an industrial camera combined with image recognition algorithms. This overcomes the blind spots of manual inspection on complex curved surfaces, captures minute geometric deviations at the joint in real time, and identifies the lateral, longitudinal, and circumferential deviations of the profile through alignment detection. Then, the lateral, longitudinal, and circumferential positions of the profile are adjusted to complete the calibration of the spatial posture of the profile.

[0078] Furthermore, the spatial orientation calibration of the profile is achieved by using a servo motor-driven precision slide in conjunction with a rotating platform. The X-axis precision slide is used to adjust the lateral position of the profile, the Y-axis precision slide is used to adjust the longitudinal position of the profile, and the rotating platform is used to adjust the circumferential position of the profile.

[0079] This approach calibrates the spatial orientation of the profile, effectively solving the problem of spatial orientation calibration caused by the complex geometry of curved profiles in welding fixtures. It significantly improves the accuracy and stability of joint alignment, avoiding defects such as uneven welding gaps, misalignment, and poor lap joints caused by transverse, longitudinal, and circumferential positional deviations, thereby ensuring the geometric consistency and quality reliability of the friction stir welding process.

[0080] In an optional implementation of this embodiment, after step S102, the aluminum alloy profiles to be welded are placed, joined together, and aligned to form a pre-welding assembly structure, such as... Figure 2 As shown, Figure 2 A schematic diagram of the butt joint assembly structure of the curved aluminum alloy profile 1 in Embodiment 1 of the present invention is shown. The butt joint assembly structure of the curved aluminum alloy profile 1 consists of five profile segments, including a first profile 11, a second profile 12, a third profile 13, a fourth profile 14 and a fifth profile 15, which are connected end to end in sequence.

[0081] Furthermore, after placing all the curved aluminum alloy profiles to be welded in the friction stir welding fixture, and performing butt welding and calibration, the profiles are now in the following state: Figure 2 As shown.

[0082] S103. The curved aluminum alloy profile to be welded is fixed in a multi-dimensional coordinated manner based on the fixing components of the friction stir welding fixture.

[0083] In one optional implementation of this embodiment, the profile to be welded must be fixed to a certain extent during the welding process, regardless of the welding method used. In traditional welding methods, the profiles to be welded are all flat profiles, so only simple left and right side clamping is required. However, in the welding of the curved aluminum alloy profile with a complex curved surface used in this embodiment, the fixing components of conventional welding fixtures lack adaptability to the curved profile, resulting in the inability to achieve uniform fit during fixing. This causes local stress concentration, displacement, and deformation during profile welding, which in turn creates a welding curve and affects the structural accuracy and connection strength of the final component.

[0084] In this embodiment, a multi-dimensional collaborative fixing method is provided for the curved aluminum alloy profile. Based on the side clamping component, vertical clamping component, and support component of the friction stir welding fixture, the curved aluminum alloy profile to be welded is fixed in a multi-dimensional manner to adapt to the curvature of the profile. This effectively solves the problems of stress concentration, displacement, and deformation caused by non-fitting fixing of the curved profile, significantly improves the uniformity of the weld and the joint accuracy, thereby ensuring the structural accuracy and connection strength of the final component.

[0085] In one optional implementation of this embodiment, such as Figure 3 and Figure 4 As shown, Figure 3 This diagram shows the reverse assembly structure of the curved aluminum alloy profile in the welding fixture according to Embodiment 1 of the present invention. Figure 4 This diagram shows the front assembly structure of the curved aluminum alloy profile in the welding fixture according to Embodiment 1 of the present invention. Figure 3 and Figure 4 In this process, the welding fixtures have been used to fix the curved aluminum alloy profile in a multi-dimensional coordinated manner.

[0086] In an optional implementation of this embodiment, the curved aluminum alloy profile to be welded is fixed based on the side clamping component in the friction stir welding fixture.

[0087] Specifically, such as Figure 5 As shown, Figure 5 The flowchart shown in Embodiment 1 of the present invention illustrates the method of fixing a profile based on a side clamping assembly, including the following steps:

[0088] S501. Analyze and extract the side profile data of the curved aluminum alloy profile to be welded;

[0089] Specifically, the shape data of the curved aluminum alloy profile to be welded obtained in step S101 is analyzed, including the curvature contour data, cross-sectional dimension data and length data, and the side contour data of the curved aluminum alloy profile to be welded is obtained through analysis.

[0090] S502. Select a suitable clamping block according to the side profile data, and assemble the clamping block onto the side clamping arm of the friction stir welding fixture.

[0091] Specifically, based on the side profile data, after selecting a clamping block whose contact surface can perfectly match the side profile data, the opposite side of the contact surface of the clamping block is assembled onto the side clamping arm of the side clamping assembly of the friction stir welding fixture.

[0092] Furthermore, clamping blocks are mounted on both side clamping arms of the side clamping assembly.

[0093] Furthermore, when the clamping block is made of a hard material, its contact surface needs to be completely matched with the side profile of the profile. When the clamping block is made of a soft material, its contact surface can be completely matched with the side profile of the profile, or it can adopt a planar structure, depending on the actual design requirements.

[0094] S503. Adjust the extension and retraction of the movable side arm of the side clamping arm relative to the fixed side arm so that the contact surface of the clamping block fits against the side of the profile.

[0095] Specifically, the side clamping assembly includes two side clamping arms, one of which is a movable side arm and the other is a fixed side arm. Here, without moving the fixed side arm, the extension and retraction of the movable side arm is adjusted so that the clamping blocks assembled on the two side clamping arms are in contact with the side of the profile.

[0096] S504. Apply a clamping force to the side of the profile based on the side clamping arm and clamping block.

[0097] Specifically, after the clamping blocks on both side clamping arms are in contact with the side of the profile, the extension and retraction of the movable side arm is increased, causing the movable side arm to extend towards the fixed side arm, forming a clamping force to clamp the side of the profile.

[0098] Furthermore, such as Figure 3 and Figure 4As shown, the friction stir welding fixture includes a side clamping assembly, which includes two side clamping arms, both of which are adjustable side clamping arms, including a first side clamping arm 31 and a second side clamping arm 32. The first side clamping arm 31 is a movable side arm that can be extended and retracted by a drive motor installed at the rear end of the arm. The extension and retraction length can be adjusted according to the structure of the profile to achieve the best clamping effect. In cooperation with it, the second side clamping arm 32 is a fixed side arm whose position is fixed. The side of the curved aluminum alloy profile 1 is fixed by the compression clamping of the first side clamping arm 31 at the other end.

[0099] Furthermore, both the tightening ends of the first side tightening arm 31 and the second side tightening arm 32 are equipped with tightening blocks 33, and the contact surface of the tightening blocks 33 is adapted to the side profile of the curved aluminum alloy profile 1.

[0100] Furthermore, the side clamping assembly set in the friction stir welding fixture refers to a device used to provide a fixing effect from the side of the profile. It can be achieved through a hydraulically driven or electrically adjustable arm structure, and its purpose is to adapt to the arc surface changes of the profile under different curvatures. Two retractable side clamping arms, located on the left and right sides respectively, are arranged facing each other and can be dynamically adjusted in position and angle. One side arm is movable, and the other is fixed. They can be understood as moving and fixed parts that cooperate with each other. The purpose is to flexibly adjust the position of the side clamping arms, thereby achieving precise matching with the curvature contour of the profile side and ensuring the flexibility and stability of adjustment. The clamping block, which is set between the two side clamping arms and the side of the profile, is a contact component. Its material can be elastic material or hard alloy. Its purpose is to disperse the clamping force brought by the side clamping arms and improve the clamping stability. The fit between the contact surface of the clamping block and the side contour of the profile means that the surface shape of the contact surface of the clamping block matches the geometric features of the profile side. The two can make close contact and achieve uniform contact surface, dispersing the clamping force on the contact surface and avoiding local stress concentration, which would lead to an unsatisfactory clamping effect.

[0101] In general, the position of the first side clamping arm 31, which is the movable side arm, relative to the second side clamping arm 32, which is the fixed side arm, is adjusted according to the curvature contour data of the profile. This ensures that the mating contact surface of the clamping block precisely fits the side contour of the profile, applies a uniform clamping force, achieves uniform force distribution during the fixing process, and realizes the stability of the side clamping.

[0102] In an optional implementation of this embodiment, the curved aluminum alloy profile to be welded is fixed based on the vertical clamping component in the friction stir welding fixture.

[0103] Specifically, such as Figure 6 As shown, Figure 6The flowchart shown in Embodiment 1 of the present invention illustrates the process of fixing a profile based on a vertical clamping assembly, including the following steps:

[0104] S601. Analyze and extract the top surface contour data of the curved aluminum alloy profile to be welded;

[0105] Specifically, the shape data of the curved aluminum alloy profile to be welded obtained in step S101 is analyzed, including the curvature contour data, cross-sectional dimension data and length data, and the top surface contour data of the curved aluminum alloy profile to be welded is obtained through analysis.

[0106] S602. Adjust the spacing of the clamping arm heads on the vertical clamping arm of the friction stir welding fixture according to the top surface contour data, so that the clamping arm heads are evenly spaced along the extension direction of the lower surface of the vertical clamping arm, and each clamping arm head can correspond to the effective clamping area of ​​the top surface of the profile.

[0107] Specifically, the position and spacing of the clamping arm heads on the lower surface of the two vertical clamping arms of the vertical clamping assembly in the friction stir welding fixture are adjusted according to the top surface contour data. The positions are evenly spaced along the extension direction of the lower surface of the vertical clamping arm, and each clamping arm head can correspond to the effective clamping area of ​​the top surface of the profile, that is, a position that does not affect the subsequent welding effect.

[0108] S603. Select a clamping arm head whose contact surface matches the top surface contour of the profile, and adjust the extension and retraction of the clamping arm head so that the contact surface of the clamping arm head can fit against the top surface of the profile.

[0109] Specifically, based on the top surface contour data, a clamping arm head whose contact surface can perfectly match the top surface contour data is selected.

[0110] Furthermore, based on the pressing position of the pressing arm head corresponding to the profile, and combined with the top surface contour data of the curved profile, the extension and retraction of each pressing arm head is adaptively adjusted so that each pressing arm head fits the corresponding position on the top surface of the profile.

[0111] S604. Apply a clamping force to the top surface of the profile based on the vertical clamping arm and the clamping arm head.

[0112] Specifically, after all the clamping arm heads on the two vertical clamping arms are in contact with the top surface of the profile, the extension and retraction of all the clamping arm heads are increased to form a vertically downward clamping force, thereby clamping the top surface of the profile.

[0113] Specifically, such as Figure 3 and Figure 4As shown, the friction stir welding fixture includes a vertical clamping assembly, which includes two vertical clamping arms. The vertical clamping arms are telescopic clamping arms, including a first vertical clamping arm 41 and a second vertical clamping arm 42. Both the first vertical clamping arm 41 and the second vertical clamping arm 42 are clamping walls that can be telescopically adjusted. The telescopic length is adjusted according to the structure of the profile by a drive motor installed at the rear end of the arm.

[0114] A plurality of clamping arm heads 43 are provided on the lower surface of the first vertical clamping arm 41 and the lower surface of the second vertical clamping arm 42. The plurality of clamping arm heads 43 are arranged at intervals along the extending direction of the lower surface of the first vertical clamping arm 41 and the lower surface of the second vertical clamping arm 42. The number, spacing and clamping degree of the clamping arm heads 43 are all set according to the shape data of the profile.

[0115] The pressing surface of the pressing arm head 43 is adapted to the top surface contour of the curved aluminum alloy profile 1, and the top surface of the curved aluminum alloy profile is fixed by the vertical downward pressing of the pressing arm head 43.

[0116] Furthermore, to ensure the actual clamping effect, the spacing between the clamping arm heads 43 must be less than 1m.

[0117] Furthermore, the vertical clamping component set in the friction stir welding fixture refers to a device used to provide a fixing effect from the top surface of the profile. It can be implemented by a retractable clamping arm driven by hydraulic, pneumatic or electric power and a clamping arm head set on the lower surface of the clamping arm. Its purpose is to provide an adjustable vertical constraint force, thereby clamping the curved aluminum alloy profile. Since this embodiment uses the welding of curved aluminum alloy profiles, when the curved aluminum alloy profile is clamped by the side clamping component, the curved protruding side of the profile may deform. Therefore, to avoid this situation, a vertical constraint force needs to be applied to the curved protruding side of the profile for vertical fixation. The two telescopic clamping arms located on the left and right sides can be dynamically adjusted in length in the horizontal direction. Their main purpose is to adapt to the length of the profile and ensure that the vertical constraint force is applied to the profile. The clamping arm head is an execution unit located on the lower surface of the clamping arm and in direct contact with the profile. The clamping arm heads are all telescopic and can be dynamically adjusted in length in the vertical direction to adjust the degree of vertical clamping on the profile. The matching of the clamping surface of the clamping arm head with the top surface contour of the profile means that the surface shape of the contact surface of the clamping arm head matches the geometric characteristics of the top surface of the profile. The two can achieve close contact and uniform contact surface, dispersing the clamping force on the contact surface and avoiding local stress concentration, which would lead to an unsatisfactory clamping effect.

[0118] In an optional implementation of this embodiment, the curved aluminum alloy profile to be welded is fixed based on the support component in the friction stir welding fixture.

[0119] Specifically, such as Figure 7 As shown, Figure 7 The flowchart illustrates the fixing of the bottom surface of the profile based on the support component in Embodiment 1 of the present invention, including the following steps:

[0120] S701. Analyze and extract the bottom contour data of the curved aluminum alloy profile to be welded;

[0121] Specifically, the shape data of the curved aluminum alloy profile to be welded obtained in step S101 is analyzed, including the curvature contour data, cross-sectional dimension data and length data, and the bottom contour data of the curved aluminum alloy profile to be welded is obtained through analysis.

[0122] S702. Adjust the spacing of the support pads of the support assembly of the friction stir welding fixture according to the bottom contour data, so that the support pads are evenly spaced along the weld extension direction of the profile, and each support pad can correspond to the effective support area of ​​the bottom surface of the profile.

[0123] Specifically, the position and spacing of all support pads in the friction stir welding fixture are adjusted according to the bottom contour data. Their positions are evenly spaced along the weld extension direction of the profile, and each support pad corresponds to the effective support area of ​​the bottom surface of the profile, that is, a position that does not affect the subsequent welding effect.

[0124] S703. Select a support pad whose contact surface matches the bottom contour of the profile, and adjust the height of the support pad so that the contact surface of the support pad can fit against the bottom surface of the profile.

[0125] Specifically, based on the bottom surface contour data, a support pad whose contact surface can perfectly match the bottom surface contour data is selected.

[0126] Furthermore, based on the support position of each support pad corresponding to the profile, and combined with the bottom contour data of the curved profile, the extension and retraction of each support pad are adaptively adjusted so that each support pad fits the corresponding position on the bottom surface of the profile.

[0127] S704. Apply a supporting force to the bottom surface of the profile based on the supporting pad.

[0128] Specifically, after all the support pads are in contact with the mantle of the profile, the expansion and contraction of all the support pads are increased to form a vertically upward supporting force, thereby supporting the bottom surface of the profile.

[0129] Specifically, such as Figure 3 and Figure 4 As shown, the friction stir welding fixture includes a support assembly, which includes several support pads 51. The support pads 51 are telescopic support pads. The height of the support pads 51 is adjusted according to the structure of the profile. The support pads 51 are arranged at intervals along the weld extension direction of the curved aluminum alloy profile 1. The number, spacing and height of the support pads 51 are all set according to the shape data of the profile. Their positions can correspond one-to-one with the clamping arm head 43. The support surface of the support pads 51 is adapted to the bottom contour of the profile.

[0130] Furthermore, to ensure the support effect, the spacing between the support pads 51 should be less than 1m.

[0131] Furthermore, the support components set in the friction stir welding fixture refer to components used to provide bottom support. Their main purpose is to provide support to the bottom of the profile to prevent deformation. When the vertical clamping components apply a downward vertical constraint force to the profile, a corresponding upward support force is also needed to firmly fix the profile. Several support pads can be considered as multiple independent support units. By discretizing the support points to adapt to the continuous curved surface characteristics of the curved aluminum alloy profile, the slight displacement of the profile caused by gravity, welding stress, and vertical constraint force during welding is suppressed, further achieving multi-dimensional fixing of the profile.

[0132] In an optional implementation of this embodiment, the method further includes: after step S103, it is necessary to perform a spacing test on the curved aluminum alloy profile to be welded; if the spacing test result does not meet the standard, the process returns to step S102.

[0133] Furthermore, the spacing of the curved aluminum alloy profile to be welded is detected using a laser alignment component or a vision alignment component.

[0134] Specifically, the laser alignment component refers to a device that uses laser technology for non-contact geometric measurement. It can be implemented using a laser rangefinder or a laser triangulation sensor, with the aim of quickly acquiring micron-level spatial parameters at the seam. The visual alignment component refers to a detection system based on the principle of optical imaging. It can be implemented using an industrial CCD camera in conjunction with an image processing unit, with the aim of identifying the seam contour features through visual algorithms. In this embodiment, the appropriate component can be selected according to actual needs.

[0135] In an optional implementation of this embodiment, in this step, three indicators are set: the butt joint spacing d1 at the profile joint, the upper and lower overlap spacing d2 at the profile overlap, and the misalignment spacing d3 at the profile joint. The obtained detection results represent the spacing detection results of the curved aluminum alloy profile to be welded.

[0136] Specifically, such as Figure 8 As shown, Figure 8 yes Figure 2 Enlarged diagram of point a in the middle. Figure 2 The schematic diagram of the butt joint assembly structure of the curved aluminum alloy profile can also be regarded as a schematic diagram of the state of the curved aluminum alloy profile 1 after multi-dimensional collaborative fixing, such as... Figure 8 As shown, Figure 8 The diagram illustrates the mating position of the second profile 12 and the third profile 13. The structure in the diagram can be considered as a butt joint structure that needs to be set at both ends of the two profiles during the welding process. The second profile 12 has a first butt joint structure 21 at one end, and the third profile 13 has a second butt joint structure 22 at one end. The first butt joint structure 21 can be considered as including two butt joint blocks located on the upper and lower top surfaces respectively. The second butt joint structure 22 has notches on the upper and lower top surfaces to match the butt joint blocks of the first butt joint structure 21 located on the upper and lower top surfaces. It also includes two butt joint blocks located on the middle surface, which are inserted into the cavity between the butt joint blocks of the first butt joint structure 21 located on the upper and lower top surfaces and overlapped. The second profile 12 and the third profile 13 are mated through the first butt joint structure 21 and the second butt joint structure 22.

[0137] It should be noted that each end of any profile is provided with a first mating structure 21 or a second mating structure 22.

[0138] Furthermore, when the first docking structure 21 and the second docking structure 22 dock together, two joints 23 and two overlaps 24 are formed. Among the three indicators set above, the docking distance d1 and the misalignment distance d3 of the profile joints are reflected in the two joints 23, while the upper and lower overlap distance d2 of the profile overlaps is reflected in the two overlaps 24.

[0139] Specifically, the butt joint spacing d1 at the profile joint refers to the distance between the two joints 23, the misalignment spacing d3 at the profile joint refers to the vertical offset between the two joints 23, and the vertical overlap spacing d2 at the profile overlap refers to the vertical distance between the two overlaps 24.

[0140] Furthermore, the value ranges of the three indicators—the butt joint spacing d1 at the profile joint, the upper and lower overlap spacing d2 at the profile overlap, and the misalignment spacing d3 at the profile joint—include:

[0141] The acceptable range for the docking spacing d1 is: d1 < 0.5 mm, and can be any one of 0.1 mm, 0.2 mm, 0.3 mm, or 0.4 mm. When the docking spacing d1 does not reach 0.5 mm, it is considered to meet the standard.

[0142] The acceptable value range for the upper and lower overlap spacing d2 is: d2 < 0.4 mm, and can be one of 0.1 mm, 0.2 mm, or 0.3 mm. When the upper and lower overlap spacing d2 does not reach 0.4 mm, it is considered to meet the standard.

[0143] The acceptable range for the misalignment distance d3 is: d3 < 0.3 mm, and can be any one of 0.1 mm, 0.15 mm, or 0.2 mm. When the misalignment distance d3 does not reach 0.3 mm, it is considered to meet the standard.

[0144] By setting three spacing detection indicators, the geometric deviations at the joints and overlaps can be accurately identified and dynamically corrected, avoiding welding defects such as incomplete welding and porosity caused by inaccurate fixing, and significantly improving the integrity and structural reliability of the welded joints of curved aluminum alloy profiles.

[0145] Furthermore, such as Figure 8 As shown, Figure 8 The first docking structure 21 and the second docking structure 22 are provided with a boss 25 at the joint 23 of the two, which is used for filling the stirring welding metal.

[0146] S104. Based on the stirring head of the friction stir welding fixture, the curved aluminum alloy profile to be welded is subjected to a first round of friction stir welding and a second round of friction stir welding.

[0147] In an optional implementation of this embodiment, the stirring head used in this step is a single-shoulder stirring head. The stirring head is made of H14 carbon tool steel. The needle length of the stirring head matches the wall thickness of the profile, and the shoulder diameter of the stirring head matches the weld width and weld depth of the profile.

[0148] Specifically, a single-shoulder stirring head refers to a design where the stirring head contains only a single shoulder structure. This can be achieved using a disc-shaped or tapered shoulder, the purpose of which is to simplify the structure to accommodate the curvature changes of curved profiles and avoid motion interference and localized stress concentration that can occur with multi-shoulder structures during welding. The stirring head is made of H14 carbon tool steel, meaning it uses carbon tool steel with high hardness and wear resistance. Other tool steels with similar hardness, such as T8A, can also be used. This is to resist high-temperature wear and plastic deformation during welding, ensuring the stirring head maintains its geometric precision during long-term operation. The length of the stirring head needle is matched with the wall thickness of the profile. The needle length parameter is dynamically adjusted according to the actual wall thickness of the profile. It can be adjusted based on the shape data of the profile collected in step S101. The purpose is to make the insertion depth of the stirring needle accurately correspond to the material thickness, ensure that the material is fully plasticized and flows, and prevent incomplete welding or bottom burn-through. The diameter of the stirring head shoulder is matched with the weld width and welding depth of the profile. The shoulder size is customized according to the geometric characteristics of the weld. The purpose is to control the contact area between the shoulder and the material, so that the heat input area accurately corresponds to the weld requirements and avoids excessive heat accumulation or insufficient heat input.

[0149] Furthermore, in this embodiment, the needle length of the stirring head is preferably 5.0 mm and the shoulder diameter is preferably 15 mm.

[0150] In an optional implementation of this embodiment, in the first round of friction stir welding in step S104, the curved aluminum alloy profile to be welded is placed in the friction stir welding fixture in a reverse assembly manner, and the reverse weld of the curved aluminum alloy profile to be welded is welded based on the stirring head of the friction stir welding fixture.

[0151] Specifically, the reverse assembly method refers to fixing the curved aluminum alloy profile in the tooling with the curved protruding side facing down, such as... Figure 3 As shown, after the curved aluminum alloy profile 1 is fixed in the tooling in a reverse assembly manner, the reverse weld of the curved aluminum alloy profile to be welded is welded based on the stirring head of the friction stir welding tooling.

[0152] In an optional implementation of this embodiment, in the second round of friction stir welding in step S104, the curved aluminum alloy profile to be welded is placed in the friction stir welding fixture in a front-side assembly manner, and the front weld of the curved aluminum alloy profile to be welded is performed based on the stirring head of the friction stir welding fixture.

[0153] Specifically, the frontal assembly method refers to fixing the curved aluminum alloy profile in the tooling with the curved protruding side facing upwards, such as... Figure 4As shown, after the curved aluminum alloy profile 1 is fixed in the tooling in a front-side assembly manner, the front weld of the curved aluminum alloy profile to be welded is welded based on the stirring head of the friction stir welding tooling.

[0154] Furthermore, in this embodiment, a high-quality connection of curved aluminum alloy profiles is achieved through a multi-round double-sided welding strategy. In the traditional welding process using gas metal arc welding (GMAW), it is recommended to perform one round of welding on the profile's weld seam. However, in the actual welding process of friction stir welding, it is impossible to achieve one round of welding. It is necessary to weld one side of the profile first and then weld the other side. Therefore, in this embodiment, a two-round welding sequence is considered, where the reverse weld seam of the profile is welded first, followed by the front weld seam of the profile, to achieve a welding step that is compatible with curved aluminum alloy profiles.

[0155] In the first round of friction stir welding, the profiles to be welded are placed in a reverse assembly configuration, allowing the stirring head to effectively target the root region of the weld. Due to the curvature distribution characteristics of the curved profiles, the reverse assembly configuration ensures a suitable contact between the stirring head and the weld root, avoiding incomplete fusion defects caused by insufficient heat input at the root during single-sided welding. After completing the first round of welding, the profiles are repositioned in a front assembly configuration for the second round of welding, allowing the stirring head to weld the surface region of the weld. The front assembly configuration optimizes the surface treatment effect of the stirring head, reducing surface oxidation and unevenness defects. Through the complementary mechanism of the two rounds of welding, the synergistic effect of double-sided heating and pressure effectively balances the distribution of residual welding stress, thereby suppressing warping deformation of the curved profiles during welding, ensuring complete fusion of the weld from root to surface, significantly improving the uniformity and structural reliability of the weld joint, and ensuring high-quality forming of the curved aluminum alloy profile assembly.

[0156] In one optional implementation of this embodiment, the weld seam of the central profile of the curved aluminum alloy profile to be welded is welded first, and then the weld seams of the profiles extending from the center to both sides are welded in sequence.

[0157] Specifically, the randomness of the welding sequence can lead to uneven distribution of thermal stress, easily causing deformation and welding defects in the curved profiles, affecting product precision and quality. Therefore, in this embodiment, based on the two rounds of welding, the further sequence of each round of welding is planned, that is, the weld seam of the central profile is welded first, and then the weld seams of the profiles extending from the center to both sides are welded in sequence. Specifically, in this embodiment, the weld seam between the second profile 12 and the third profile 13, and the weld seam between the third profile 13 and the fourth profile 14 are welded first. Welding is performed on the welds between the first profile 11 and the second profile 12, and on the welds between the fourth profile 14 and the fifth profile 15, thus completing one round of welding. This allows the thermal stress to be symmetrically distributed along the length of the profile, preventing local heat accumulation and stress concentration. Especially for the curved surface characteristics of the curved profile, it effectively maintains the accuracy of the curved contour, reduces twisting, misalignment or lap defects caused by asymmetric thermal stress, effectively controls the distribution of thermal stress, and improves the geometric accuracy and quality consistency of the components formed after welding.

[0158] S105. After completing two rounds of friction stir welding, the welded curved aluminum alloy profile is cooled to obtain the formed curved aluminum alloy profile assembly.

[0159] In one optional implementation of this embodiment, after completing the two rounds of friction stir welding in step S104, the welded curved aluminum alloy profile is cooled, which may include natural cooling, air cooling or water cooling, to obtain the formed curved aluminum alloy profile assembly.

[0160] In an optional implementation of this embodiment, the welding process parameters of the friction stir welding include: welding tilt angle of 2°-3°, preferably 2.5°; spindle pressure of 1T-2T, preferably 1.5T; rotation speed of 2800r / min-3000r / min; and welding speed of 1800mm / min-2000mm / min, which is more than 60% higher than the conventional MIG welding speed of 1100mm / min.

[0161] The product produced in this embodiment has a tensile strength of 257 MPa, which is about 86% of the strength of the base material. Compared with the conventional MIG welding product, which has a tensile strength of about 60% of the base material, the mechanical properties of the weld are significantly improved.

[0162] In this embodiment, the weld surface groove formed by friction stir welding has no abnormal depth and a more beautiful shape. Moreover, there is no smoke, arc light and low noise during the welding process. Furthermore, there is no need to use consumables such as welding wire, shielding gas and contact nozzle. Only a stirring head is used, which reduces the overall consumable cost by about 75%.

[0163] In summary, Embodiment 1 of this invention provides a friction stir welding method for curved aluminum alloy profiles. By collecting shape data of the curved aluminum alloy profile to be welded, including its curvature profile, cross-sectional dimensions, and length, and matching it with a dedicated friction stir welding fixture, the method employs precise spatial orientation calibration, multi-dimensional collaborative fixing, and a multi-stage welding process. This effectively controls the joint quality, achieving high-precision and high-strength curved profile connections. It solves the problems of displacement deformation and joint misalignment that easily occur during the welding of curved aluminum alloy profiles in traditional welding methods, improving welding accuracy and quality. It avoids the defects of traditional welding methods, such as material strength attenuation, stringent environmental requirements, and environmental pollution. The method boasts advantages such as fast welding speed, high welding strength, low welding environmental requirements, and low welding cost, effectively improving the quality of the formed products and meeting the comprehensive requirements of high-end equipment for forming accuracy, production efficiency, and environmental protection.

[0164] The above provides a detailed description of a friction stir welding method for curved aluminum alloy profiles provided by the present invention. Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, which may include: read-only memory (ROM), random access memory (RAM), disk or optical disk, etc.

[0165] Furthermore, the embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A friction stir welding method of a radiused aluminum alloy profile, characterized by, The welding method comprises: S101, collecting shape data of the aluminum alloy profile with an arc to be welded, and matching a friction stir welding tool based on the collected shape data; S102, placing the aluminum alloy profile with an arc to be welded in the matched friction stir welding tool, and calibrating the spatial posture of the aluminum alloy profile with an arc to be welded; S103, performing multidimensional cooperative fixing on the aluminum alloy profile with an arc to be welded based on a fixing assembly of the friction stir welding tool; S104, performing first round and second round friction stir welding on the aluminum alloy profile with an arc to be welded respectively based on a stir head of the friction stir welding tool; S105, after completing the two rounds of friction stir welding, performing cooling treatment on the aluminum alloy profile with an arc to be welded, and obtaining a formed aluminum alloy profile assembly with an arc; The method further comprises: after step S103, detecting the spacing of the aluminum alloy profile with an arc to be welded by a laser alignment assembly or a visual alignment assembly, and returning to step S102 if the spacing detection result is not up to standard; The spacing detection of the aluminum alloy profile with an arc to be welded by the laser alignment assembly or the visual alignment assembly comprises: detecting the butt joint spacing d1 of the joint of the profile, wherein the up-to-standard value range of the butt joint spacing d1 is d1 < 0.5mm; detecting the upper and lower lap joint spacing d2 of the lap joint of the profile, wherein the up-to-standard value range of the upper and lower lap joint spacing d2 is d2 < 0.4mm; detecting the misalignment spacing d3 of the joint of the profile, wherein the up-to-standard value range of the misalignment spacing d3 is d3 < 0.3mm.

2. The method of friction stir welding of a radiused aluminum alloy profile of claim 1, wherein, In step S101, the collecting of the shape data of the aluminum alloy profile with an arc to be welded and the matching of the friction stir welding tool based on the collected shape data comprise: precisely collecting the arc profile data, cross-sectional size data and length data of the aluminum alloy profile with an arc to be welded, and selecting the matched friction stir welding tool based on the collected arc profile data, cross-sectional size data and length data.

3. The method of friction stir welding of a radiused aluminum alloy profile of claim 1, wherein, In step S102, the placing of the aluminum alloy profile with an arc to be welded in the matched friction stir welding tool and the calibration of the spatial posture of the aluminum alloy profile with an arc to be welded comprise: placing the aluminum alloy profile with an arc to be welded in the friction stir welding tool based on a preset placement mode, detecting the alignment of the joint of the profile by a laser alignment assembly or a visual alignment assembly, and adjusting the transverse position, longitudinal position and circumferential position of the profile based on the alignment detection result.

4. The method of friction stir welding of a radiused aluminum alloy shape as defined in claim 1, wherein In step S103, the multidimensional cooperative fixing of the aluminum alloy profile with an arc to be welded based on the fixing assembly of the friction stir welding tool comprises: analyzing and extracting the side profile data of the aluminum alloy profile with an arc to be welded; selecting the matched top block according to the side profile data, and assembling the top block to the side top arm of the friction stir welding tool; Adjust the telescopic amount of the movable side arm of the side clamping arm relative to the fixed side arm, so that the contact surface of the clamping block is in close contact with the side surface of the profile; The side clamping arm and the clamping block exert a clamping force on the side surface of the profile.

5. The method of friction stir welding of a radiused aluminum alloy shape as defined in claim 1, wherein, In step S103, the multi-dimensional collaborative fixing of the aluminum alloy profile to be welded by the fixing assembly of the friction stir welding tooling further comprises: Extract the top surface profile data of the aluminum alloy profile to be welded; Adjust the spacing of the pressure arm heads on the vertical pressure arm of the friction stir welding tooling according to the top surface profile data, so that the pressure arm heads are uniformly spaced along the extension direction of the lower surface of the vertical pressure arm, and each pressure arm head can correspond to the effective pressure area of the top surface of the profile; Select the pressure arm heads with contact surfaces that match the top surface profile of the profile, and adjust the telescopic amount of the pressure arm heads, so that the contact surfaces of the pressure arm heads can be in close contact with the top surface of the profile; The vertical pressure arm and the pressure arm heads exert a pressure force on the top surface of the profile.

6. The method of friction stir welding of a radiused aluminum alloy shape as defined in claim 1, wherein, In step S103, the multi-dimensional collaborative fixing of the aluminum alloy profile to be welded by the fixing assembly of the friction stir welding tooling further comprises: Extract the bottom surface profile data of the aluminum alloy profile to be welded; Adjust the spacing of the support pads of the support assembly of the friction stir welding tooling according to the bottom surface profile data, so that the support pads are uniformly spaced along the extension direction of the weld of the profile, and each support pad can correspond to the effective support area of the bottom surface of the profile; Select the support pads with contact surfaces that match the bottom surface profile of the profile, and adjust the height of the support pads, so that the contact surfaces of the support pads can be in close contact with the bottom surface of the profile; The support pads exert a support force on the bottom surface of the profile.

7. The method of friction stir welding of a radiused aluminum alloy shape as defined in claim 1, wherein, In step S104, the stirring head is a single shaft shoulder stirring head, the material of the stirring head is H14 carbon tool steel, the length of the needle of the stirring head matches the wall thickness of the profile, and the diameter of the shaft shoulder of the stirring head matches the weld width and weld depth of the profile.

8. The method of friction stir welding of a radiused aluminum alloy shape as defined in claim 1, wherein, In the first round of friction stir welding in step S104, the aluminum alloy profile to be welded is placed in the friction stir welding tooling in a reverse assembly manner, and the reverse weld of the aluminum alloy profile to be welded is welded based on the stirring head of the friction stir welding tooling. In the second round of friction stir welding in step S104, the aluminum alloy profile to be welded is placed in the friction stir welding tooling in a front assembly manner, and the front weld of the aluminum alloy profile to be welded is welded based on the stirring head of the friction stir welding tooling.

9. The method of friction stir welding of a radiused aluminum alloy shape as defined in claim 1, wherein, In step S104, the weld of the center profile in the aluminum alloy profile to be welded is welded first, and then the welds of the profiles extending in both directions from the center are welded in sequence.

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