A local vacuum laser welding device

Abstract

This invention provides a local vacuum laser welding device, including a vacuum hood and a sealing structure. The sealing structure includes an elastic sealing ring and a weld sealing strip assembly. The elastic sealing ring is connected to the bottom end face of the vacuum hood and surrounds the hood opening. A fixing groove is formed on the elastic sealing ring. The weld sealing strip assembly is snapped into the fixing groove. The weld sealing strip assembly includes a strip-shaped elastic body, a heat-insulating elastic strip, and a first high-temperature resistant elastic gasket. The heat-insulating elastic strip is connected to the bottom end face of the strip-shaped elastic body, and the first high-temperature resistant elastic gasket is connected to the bottom end face of the heat-insulating elastic strip and can fit against the outer wall surface of the weld by its own deformation. The porosity of the heat-insulating elastic strip is higher than that of the first high-temperature resistant elastic gasket. This invention can achieve precise and gapless fitting and matching between the weld sealing strip assembly and the outer wall surface of the weld reinforcement during the welding process, ensuring that the vacuum degree is stably maintained at a preset value and improving the quality of vacuum laser welding.

Description

Technical Field

[0001] This invention belongs to the field of vacuum laser welding equipment design technology, and specifically relates to a local vacuum laser welding device. Background Technology

[0002] With the development of aerospace, deep-sea and other fields towards larger scale and higher performance, the demand for large-size and thick metal components is increasing. Welding, as a key process in the fabrication of large components, directly affects structural performance. Currently, welding of thick plates mainly uses arc welding and electron beam welding. Arc welding is prone to defects such as porosity and cracks, and multi-layer, multi-pass welding has low efficiency and high residual stress. Although electron beam welding has high joint strength, it is limited by the size of the vacuum chamber and is difficult to use for large components. Furthermore, the high vacuum environment (10) -5 ~10 -2 Pa) and electromagnetic interference increased costs and difficulties.

[0003] Laser welding boasts advantages such as high energy density, minimal welding deformation, and high flexibility, and has been widely applied in aerospace, shipbuilding, automotive, and electronics industries. However, laser welding in an atmospheric environment inevitably generates plasma plumes, which enhance the laser shielding effect. Because the laser beam is absorbed by the dense plumes, the energy transmission efficiency is significantly reduced, resulting in a substantial decrease in weld penetration. Therefore, atmospheric laser welding is primarily concentrated on thin and medium-thick plates.

[0004] To improve energy utilization in laser welding, vacuum laser welding technology has been proposed, opening up new avenues for laser welding applications. This method performs laser welding in a vacuum environment, effectively suppressing plasma plume generation and significantly increasing weld penetration. Furthermore, vacuum laser welding technology can be applied even in low vacuum (10⁻⁶ m / s²). -1 ~10 4 Vacuum laser welding, performed in a vacuum environment, not only significantly improves welding efficiency but also saves processing costs. Therefore, it shows broad application prospects for welding thick plate components in important industrial fields such as aerospace, automobiles, and shipbuilding.

[0005] Although the vacuum level of full-vacuum laser welding is significantly lower than that of electron beam welding, enabling the welding of thick plate components, the full-vacuum chamber is extremely expensive and difficult to manufacture for large components tens or hundreds of meters in length. In reality, most components require welding in localized areas. Therefore, localized vacuum laser welding is a highly efficient, reliable, and economical method for manufacturing large, thick-walled equipment. Localized vacuum laser welding technology has advantages such as low energy consumption, high efficiency, and a small heat-affected zone on the workpiece. It can be used in aerospace, automotive manufacturing, and precision electronics. Its core principle is to create a stable localized vacuum environment in the weld area, preventing defects such as oxidation, porosity, and slag inclusions caused by contact between the molten metal pool and air during welding. Therefore, the reliability of the sealing structure directly determines the weld quality.

[0006] The sealing methods currently used in local vacuum welding have several technical limitations: (1) Traditional sealing materials are usually flat silicone pads or rubber elastomer sealing materials, which are difficult to fully fit the arc-shaped contour of the weld reinforcement (after the weld is rapidly melted by vacuum laser welding, a weld reinforcement will be formed during the condensation process. The surface of the weld reinforcement is uneven, also known as fish scale weld reinforcement, which is prone to gaps with the sealing material and vacuum leakage); (2) High temperature failure: The temperature of the weld area is extremely high during laser welding, often exceeding 1500℃. Single silicone or rubber materials are prone to softening, aging or melting under continuous high temperature radiation, thus quickly losing sealing performance and having poor durability; (3) Insufficient sealing reliability: Single materials often cannot meet the dual requirements of elastic fit and high temperature resistance at the same time, and the sealing edge often leaks due to uneven pressure distribution, which directly affects the stability of the local vacuum environment.

[0007] To address these issues, some studies have attempted to apply high-temperature resistant coatings to the surface of sealing materials. However, these coatings are prone to peeling off and still cannot adapt to changes in the weld shape. Other studies have used ceramic gaskets, but due to their brittleness and lack of necessary elasticity, the sealing effect remains unsatisfactory. Therefore, there is an urgent need for a composite sealing structure that combines good contour fit, excellent high-temperature resistance, and high reliability to effectively meet the stringent sealing performance requirements of local vacuum laser welding. Summary of the Invention

[0008] Therefore, the present invention provides a local vacuum laser welding device that can overcome the shortcomings of existing local vacuum welding devices, such as insufficient fit between the sealing structure and the weld reinforcement surface contour, which leads to unstable maintenance of vacuum during the welding process and reduced vacuum laser welding quality.

[0009] To address the aforementioned problems, this invention provides a local vacuum laser welding device, comprising a vacuum hood and a sealing structure. The sealing structure includes an elastic sealing ring and a weld sealing strip assembly. The vacuum hood has a hood hole positioned opposite to the workpiece to be welded. The elastic sealing ring is connected to the bottom end face of the vacuum hood and surrounds the hood hole. A fixing groove is formed on the bottom end face of the elastic sealing ring. The weld sealing strip assembly is snap-fitted into the fixing groove. The weld sealing strip assembly includes a strip-shaped elastic body, a heat-insulating elastic strip, and a first high-temperature resistant elastic gasket, arranged sequentially along the direction close to the workpiece to be welded. The heat-insulating elastic strip is connected to the bottom end face of the strip-shaped elastic body. The first high-temperature resistant elastic gasket is connected to the bottom end face of the heat-insulating elastic strip and can adhere to the outer wall of the weld seam by its own deformation. The porosity of the heat-insulating elastic strip is higher than that of the first high-temperature resistant elastic gasket.

[0010] In some embodiments, the strip-shaped elastic body has a hollow cavity recessed toward the side away from the workpiece to be welded, the heat-insulating elastic strip is sealed to the opening of the hollow cavity, the hollow cavity is filled with pressurized fluid; and / or, an auxiliary positioning groove is formed on the bottom end face of the vacuum shroud that engages with the top end face of the strip-shaped elastic body.

[0011] In some embodiments, the local vacuum laser welding apparatus further includes an active cooling circulation component, which includes a cooling component, a circulating pressurizing pump, a return pipe, and an inlet pipe. Both the return pipe and the inlet pipe are connected to the hollow cavity. The pressurized fluid is cooling water. The circulating pressurizing pump is used to circulate the cooling water under pressure between the cooling component and the hollow cavity through the return pipe and the inlet pipe.

[0012] In some embodiments, two filling tubes are formed on the strip-shaped elastic body at both ends of its length. The two filling tubes are respectively located on the inner and outer sides of the elastic sealing ring. The active cooling circulation component is circulated with the hollow cavity through each of the filling tubes. The vacuum cover is formed with positioning through holes. Each of the filling tubes is inserted into the positioning through holes one by one to realize the detachable connection between the weld sealing strip assembly and the vacuum cover.

[0013] In some embodiments, the filling tube is interference-fitted with the positioning through hole, and an anti-slip sealing structure is formed between the mating wall surfaces of the filling tube and the positioning through hole; and / or, the inlet tube is connected to the filling tube located inside the elastic sealing ring.

[0014] In some embodiments, the anti-slip sealing structure includes multiple first anti-detachment rings formed on the outer wall of the filling tube and multiple second anti-detachment rings formed on the inner wall of the positioning through hole. Each first anti-detachment ring and each second anti-detachment ring extends around the circumference of the positioning through hole, and the depth direction of each positioning through hole is staggered to form a concave-convex fit.

[0015] In some embodiments, the weld sealing strip assembly further includes a second high-temperature resistant elastic gasket, the second high-temperature resistant elastic gasket being located between the heat-insulating elastic strip and the strip-shaped elastic body; and / or, the elastic sealing ring includes an insert ring fitted into an assembly ring groove on the bottom end of the vacuum shroud, the assembly ring groove being a constricted groove, and the cross-sectional shape of the insert ring matching the cross-sectional shape of the assembly ring groove.

[0016] In some embodiments, a filling annular cavity is formed within the insert ring, the filling annular cavity extending along the circumferential direction of the insert ring and being used to fill pressurized fluid.

[0017] In some embodiments, the porosity of the thermal insulation elastic strip is higher than that of the second high-temperature resistant elastic pad; and / or, the porosity of the thermal insulation elastic strip is 40%-90%, and the porosity of the first and second high-temperature resistant elastic pads is ≤40%.

[0018] In some embodiments, the weld seal assembly has two symmetrical sections about the cover hole.

[0019] The local vacuum laser welding device provided by this invention has the following beneficial effects:

[0020] The sealing structure includes a weld sealing strip assembly designed to address the weld reinforcement. This assembly comprises stacked strip-shaped elastic bodies, a heat-insulating elastic strip, and a first high-temperature resistant elastic gasket, forming a composite structure resembling a "sandwich." The heat-insulating elastic strip has a higher porosity than the first high-temperature resistant elastic gasket, thus effectively isolating the weld from high temperatures (potentially exceeding 1000°C). This creates a thermal barrier for components on the side of the first high-temperature resistant elastic gasket away from the weld, avoiding the softening, ablation, and failure problems common with traditional polymer sealing materials. This achieves stable high-temperature performance for all components of the sealing structure throughout the entire laser welding cycle. The sandwich composite structure is highly resistant to heat and moisture. Meanwhile, the elasticity of each layer allows the first high-temperature resistant elastic gasket to adapt to the weld reinforcement and workpiece surface morphology during initial compression, maintaining sufficient elasticity and contact pressure during the welding thermal cycle. This actively compensates for microscopic gaps that may arise due to thermal expansion and contraction. Simultaneously, the middle heat-insulating elastic strip utilizes its thermal barrier function to ensure the dimensional stability of the entire sealing structure, preventing overall softening and deformation caused by high temperatures. This synergistic stability of performance ensures that the local vacuum cavity maintains an effective vacuum seal throughout the entire process from welding to cooling, significantly improving reliability and welding quality. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. The drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0022] Figure 1 This is a three-dimensional structural schematic diagram of the local vacuum laser welding device of the present invention in one embodiment, where the laser welding head is not shown.

[0023] Figure 2 This is a three-dimensional structural diagram (expanded structure) of the local vacuum laser welding device of the present invention in another embodiment, where the laser welding head is not shown.

[0024] Figure 3 yes Figure 2 A three-dimensional structural diagram of the weld sealing strip assembly in the image;

[0025] Figure 4 yes Figure 3 A schematic cross-sectional view of the weld seal strip assembly in the diagram;

[0026] Figure 5 yes Figure 2 The diagram shows a partial internal structure of a local vacuum laser welding device, with the flow path of the pressurized fluid shown in the figure.

[0027] Figure 6 yes Figure 2 A partial structural diagram (section) of the assembly of the elastic sealing ring and the sealing cover in the middle.

[0028] Figure 7 The weld surface morphology obtained by using local vacuum laser welding devices with different sealing structures is shown in (a). The local vacuum laser welding device corresponding to (b) adopts the sealing structure of the present invention. The local vacuum laser welding device corresponding to (c) does not adopt the sealing structure of the present invention but adopts a single high-temperature resistant elastic gasket (i.e., the first high-temperature resistant elastic gasket). The local vacuum laser welding device corresponding to (c) does not adopt the sealing structure of the present invention but adopts a single high-porosity heat insulation layer (i.e., heat insulation elastic strip).

[0029] The attached figures are labeled as follows:

[0030] 1. Vacuum hood; 11. Hoist hole; 12. Positioning through hole; 13. Auxiliary positioning groove; 14. Assembly ring groove; 2. Elastic sealing ring; 20. Fixing groove; 21. Embedded ring; 211. Filling ring cavity; 3. Weld seam sealing strip assembly; 31. Strip-shaped elastic body; 312. Hollow cavity; 313. Filling tube; 314. Anti-slip sealing structure; 32. Heat-insulating elastic strip; 33. First high-temperature resistant elastic gasket; 34. Second high-temperature resistant elastic gasket; 41. Refrigeration component; 42. Circulating pressurization pump; 43. Return pipe; 44. Inlet pipe; 61. Laser incident tube; 62. Vacuum port; 63. O-ring seal; 64. Connecting screw. Detailed Implementation

[0031] 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. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. 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.

[0032] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0033] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90° or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0034] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0035] See also Figures 1 to 7 As shown in the figure, according to an embodiment of the present invention, a local vacuum laser welding apparatus is provided, including a vacuum hood 1 and a sealing structure (not indicated in the figure). The sealing structure includes an elastic sealing ring 2 and a weld sealing strip assembly 3. The vacuum hood 1 has a hood hole 11 disposed opposite to the workpiece to be welded. See details below. Figure 1As shown, on the side of the vacuum chamber 1 away from the workpiece to be welded, a laser incident tube 61 and a laser incident window lens (not shown in the figure) are arranged sequentially along the direction away from the workpiece. The laser incident tube 61 has connecting flanges at both ends (not labeled in the figure). The connecting flange at the lower end of the laser incident tube 61 is detachably connected to the vacuum chamber 1 by corresponding connecting screws 64. The laser incident window lens is specifically fixed to the connecting flange at the upper end of the laser incident tube 61 by a lens clamping plate (not labeled in the figure). In actual use, a corresponding laser welding head (i.e., a laser generating component, not shown in the figure) is also arranged on the top side end face of the laser clamping plate (i.e., the side end face away from the workpiece to be welded). It can be understood that the central hole of the aforementioned laser incident tube 61 is the laser incident channel. Simultaneously, an air extraction port 62 communicating with the central hole is formed on the side wall of the laser incident tube 61. The aforementioned extraction port 62 allows for controllable communication with external vacuum components (such as a vacuum pump and corresponding vacuum bellows), thereby creating a localized vacuum environment for laser welding. To ensure the stability of the vacuum level, corresponding O-ring seals 63 are provided between the assembly surfaces of the corresponding components. The elastic sealing ring 2 is connected to the bottom end face of the vacuum shroud 1 and surrounds the shroud hole 11. A fixing groove 20 is formed on the bottom end face of the elastic sealing ring 2 (i.e., the end face near the workpiece to be welded). The weld sealing strip assembly 3 is snapped into the fixing groove 20. This allows the weld sealing strip assembly 3 and the elastic sealing ring 2 to form a cross-shaped interlocking connection at the fixing groove 20, which significantly improves the connection strength between the elastic sealing ring 2 and the vacuum shroud 1, while also enhancing the deformation resistance of the elastic sealing ring 2. The weld sealing strip assembly 3 includes components along the direction close to the workpiece to be welded (i.e., Figure 1 The strip elastic body 31, the heat-insulating elastic strip 32, and the first high-temperature resistant elastic gasket 33 are arranged sequentially from top to bottom in the indicated orientation. The heat-insulating elastic strip 32 is connected to the bottom end face of the strip elastic body 31, and the first high-temperature resistant elastic gasket 33 is connected to the bottom end face of the heat-insulating elastic strip 32 and can adhere to the outer wall of the weld by its own deformation. The porosity of the heat-insulating elastic strip 32 is higher than that of the first high-temperature resistant elastic gasket 33. Preferably, the porosity of the heat-insulating elastic strip 32 is also higher than that of the strip elastic body 31, that is, its porosity is the highest among the relevant materials in the sealing structure.

[0036] In this technical solution, the sealing structure includes a weld sealing strip assembly 3 designed for the weld reinforcement. This assembly comprises a strip-shaped elastic body 31 stacked vertically, a heat-insulating elastic strip 32, and a first high-temperature resistant elastic gasket 33, forming a composite structure resembling a "sandwich." The porosity of the heat-insulating elastic strip 32 is higher than that of the first high-temperature resistant elastic gasket 33, thus utilizing its high porosity to effectively isolate the high temperature of the weld (potentially exceeding 1000℃). This forms a thermal barrier for components on the side of the first high-temperature resistant elastic gasket 33 away from the weld, avoiding the softening, ablation, and failure problems common with traditional polymer sealing materials. This achieves a sealing structure that is fully functional throughout the entire laser welding cycle. The components exhibit stable high-temperature resistance. Simultaneously, the elasticity of each layer in the sandwich composite structure allows the first high-temperature resistant elastic gasket 33 to adapt to the weld reinforcement and workpiece surface morphology during initial compression, maintaining sufficient elasticity and contact pressure during welding thermal cycling. This actively compensates for microscopic gaps that may arise due to thermal expansion and contraction. Meanwhile, the intermediate heat-insulating elastic strip 32 utilizes its thermal barrier function to ensure the dimensional stability of the entire sealing structure, preventing overall softening and deformation caused by high temperatures. This synergistic stability ensures that the local vacuum cavity maintains an effective vacuum seal throughout the entire process from welding to cooling, significantly improving reliability and welding quality. It is worth emphasizing that the porosity of the aforementioned first high-temperature resistant elastic gasket 33 is lower than that of the heat-insulating elastic strip 32, meaning it is more dense. This reduces the contact friction between the first high-temperature resistant elastic gasket 33 and the weld, lowering the probability of breakage and increasing its service life.

[0037] It is particularly important to emphasize that traditional sealing solutions, due to limitations in the performance of a single material, often struggle to achieve a balance between high-temperature resistance and surface morphology fit. To address this, this invention breaks through the limitations of homogeneous material thinking and instead adopts a functionally graded composite design concept. By constructing a "sandwich" sealing structure, materials with different properties are spatially distributed in an orderly manner, thereby integrating the two mutually restrictive functions of "interface elastic sealing" and "body thermal insulation protection".

[0038] In addition, the weld sealing strip assembly 3 and the aforementioned elastic sealing ring 2 overlap at the fixing groove 20, that is, the two are cross-locked into one, and together they construct a stable and leak-proof local vacuum environment.

[0039] The aforementioned first high-temperature resistant elastic gasket 33, as a component in direct contact with the weld, is subjected to high-temperature welding. Its temperature resistance is 1000~1800℃, effectively isolating heat radiation, preventing the elastomeric sealing material from softening and aging, and significantly extending its service life. More importantly, the first high-temperature resistant elastic gasket 33, with its excellent thermal stability and ablation resistance, can also block the transfer of welding heat from the weld to the heat-insulating elastic strip 32 on it to a certain extent, forming a thermal isolation barrier together with the heat-insulating elastic strip 32, preventing other sealing components from failing due to softening or decomposition at high temperatures. The strip-shaped elastic body 31 can provide high elasticity to ensure reliable and efficient adaptation and compensation of the first high-temperature resistant elastic gasket 33 and the heat-insulating elastic strip 32 to changes in the shape of the weld outer wall, while also having a certain rigidity to ensure the structural stability and reliability of the entire weld sealing strip assembly 3.

[0040] Furthermore, it should be noted that the two ends of the aforementioned first high-temperature resistant elastic gasket 33 protrude from the inner and outer walls of the elastic sealing ring 2, thereby enabling a relatively long matching fit with the weld. This length matching helps to improve the tightness of its fit with the outer wall surface of the weld reinforcement, ensuring the sealing effect at the weld position. In a specific embodiment, the length of the aforementioned first high-temperature resistant elastic gasket 33 (i.e., the overall length of the weld sealing strip assembly 3) should be at least four times greater than the ring wall thickness of the elastic sealing ring 2.

[0041] See also Figures 2 to 5 As shown, in some embodiments, the strip-shaped elastic body 31 has a recess toward the side away from the workpiece to be welded (i.e., Figure 2 The hollow cavity 312 (recessed on the upward side as shown) is specifically connected to the bottom end face of the hollow cavity 312 by a high-temperature resistant adhesive. In a preferred embodiment, the hollow cavity 312 has an opening facing the workpiece to be welded. At this time, the heat-insulating elastic strip 32 is sealed to the opening of the hollow cavity 312. That is, the hollow cavity 312 is formed by the heat-insulating elastic strip 32 and the strip elastic body 31 together to form a sealed cavity. At this time, the heat-insulating elastic strip 32 can exist as the bottom wall surface of the strip elastic body 31. The hollow cavity 312 is filled with pressurized fluid.

[0042] In this technical solution, a hollow cavity 312 is provided inside the strip-shaped elastic body 31. The hollow cavity 312 can be filled with pressurized fluid. In this way, the self-filling pressure of the pressurized fluid can be used to form a relatively balanced and flexible pressure on the heat-insulating elastic strip 32 and the first high-temperature resistant elastic pad 33 below it. This can improve the deformation ability of the first high-temperature resistant elastic pad 33 and the heat-insulating elastic strip 32 at different weld positions.

[0043] In some embodiments, an auxiliary positioning groove 13 is formed on the bottom surface of the vacuum chamber 1, which engages with the top surface of the strip-shaped elastic body 31. It is understood that the length of the auxiliary positioning groove 13 is approximately the same as the length of the strip-shaped elastic body 31. This makes the overall structure of the strip-shaped elastic body 31 (and the weld sealing strip assembly 3) more stable, preventing vacuum leakage caused by the detachment of the weld sealing strip assembly 3 or displacement deviation during welding. In some embodiments, an anti-slip structure is provided between the auxiliary positioning groove 13 and the top surface of the strip-shaped elastic body 31. This anti-slip structure can be, for example, multiple horizontal bars and grooves perpendicular to the length direction of the weld, i.e., the length direction of the strip-shaped elastic body 31. One of the horizontal bars and grooves is located on the groove wall of the auxiliary positioning groove 13, and the other is located on the top surface of the strip-shaped elastic body 31. Each horizontal bar and groove corresponds to a concave-convex fit, thus preventing the weld sealing strip assembly 3 from being flipped and unstable during welding.

[0044] See details Figure 2 As shown, in some embodiments, the local vacuum laser welding apparatus further includes an active cooling circulation component (not indicated in the figure). The active cooling circulation component includes a cooling component 41, a circulating pressurizing pump 42, a return pipe 43, and an inlet pipe 44. Both the return pipe 43 and the inlet pipe 44 can communicate with the hollow cavity 312. The pressurized fluid is cooling water. The circulating pressurizing pump 42 is used to form a pressure circulation of the cooling water between the cooling component 41 and the hollow cavity 312 through the return pipe 43 and the inlet pipe 44. The aforementioned cooling component 41 can be, for example, an air-cooled heat exchanger or a water-cooled heat exchanger, which can cool the pressurized fluid flowing within it. In a specific embodiment, the aforementioned cooling component 41 includes a cooling water tank and a cooling device (such as a semiconductor cooling component) assembled on the cooling water tank. The cooling water flows into the cooling water tank under the action of the aforementioned circulating pressurizing pump 42 and is cooled and dissipated.

[0045] In this technical solution, cooling water is used as the aforementioned pressurized fluid. Its positive pressure enables the outward expansion and deformation of the aforementioned heat-insulating elastic strip 32 and the first high-temperature resistant elastic pad 33, ensuring that the first high-temperature resistant elastic pad 33 can more efficiently deform and fit seamlessly with different positions on the outer wall of the weld, ensuring sealing. Simultaneously, an active cooling circulation component circulates and cools the cooling water, significantly reducing the temperature rise of the heat-insulating elastic strip 32, the first high-temperature resistant elastic pad 33, the strip-shaped elastic body 31, and the vacuum chamber 1. This reduces the difficulty of material selection for each component. In particular, due to the active cooling capability, the lower temperature limit of the first high-temperature resistant elastic pad 33 can be reasonably lowered, thus reducing design and manufacturing costs. It is understood that the pumping pressure of the aforementioned circulating pressurization pump 42 can be reasonably determined based on the cooling requirements and the pressure requirements of the pressurized fluid.

[0046] In some embodiments, two filling tubes 313 are formed on the strip-shaped elastic body 31 at both ends of its length. The two filling tubes 313 are respectively located on the inner and outer sides of the elastic sealing ring 2. The active cooling circulation component is circulated with the hollow cavity 312 through each of the filling tubes 313. The vacuum cover 1 is formed with positioning through holes 12. Each of the filling tubes 313 is inserted into each positioning through hole 12 in a corresponding manner to realize the detachable connection between the weld sealing strip assembly 3 and the vacuum cover 1. The aforementioned hollow cavity 312 can be as long as possible along the length of the weld while ensuring the structural strength of the strip-shaped elastic body 31.

[0047] In this technical solution, the filling tube 313 serves as a conduit for the flow of pressurized fluid into the hollow cavity 312, ensuring smooth circulation of the pressurized fluid. On the other hand, it also serves as a positioning connection structure between the weld sealing strip assembly 3 and the vacuum chamber 1, enabling a detachable connection between the two. This facilitates quick replacement of the weld sealing strip assembly 3 with a more suitable size and shape under different welding conditions, improving the versatility of the device. Furthermore, the filling tube 313 is located at both ends of the strip elastic body 31, forming a fixed-point positioning for both ends of the strip elastic body 31, which further enhances the positional reliability and stability of the weld sealing strip assembly 3 during the welding process.

[0048] In some embodiments, the filling tube 313 is interference-fitted with the positioning through hole 12, and an anti-slip sealing structure 314 is formed between the mating wall surfaces of the filling tube 313 and the positioning through hole 12. As a specific embodiment, the anti-slip sealing structure 314 includes multiple first anti-detachment rings (not labeled in the figure) formed on the outer wall of the filling tube 313 and multiple second anti-detachment rings (not labeled in the figure) formed on the inner wall of the positioning through hole 12. Each first anti-detachment ring and each second anti-detachment ring extends around the circumference of the positioning through hole 12, and the depth direction of each positioning through hole 12 is staggered to form a concave-convex fit.

[0049] In this technical solution, the aforementioned anti-slip sealing structure 314 utilizes its anti-detachment rings to form a concave-convex fit structure, which on the one hand can improve the friction and fastening force between two adjacent mating parts, the position reliability of the weld sealing strip assembly 3, and effectively prevent the anti-detachment phenomenon from occurring. On the other hand, it can form a labyrinth sealing effect for pressurized fluids, preventing pressurized fluid leakage.

[0050] In some embodiments, the inlet pipe 44 is connected to the filling pipe 313 located inside the elastic sealing ring 2. That is, the lower temperature pressure fluid (cooling water) is first introduced into the hollow cavity 312 in the inner region of the elastic sealing ring 2 to exchange heat with the higher temperature region before flowing out through the return pipe 43. This is beneficial to improve the cooling effect of the pressure fluid.

[0051] In some embodiments, the weld sealing strip assembly 3 further includes a second high-temperature resistant elastic gasket 34, which is located between the heat-insulating elastic strip 32 and the strip-shaped elastic body 31.

[0052] In some embodiments, the porosity of the thermal insulation elastic strip 32 is also higher than that of the second high-temperature resistant elastic pad 34. In some embodiments, the second high-temperature resistant elastic pad 34 and the first high-temperature resistant elastic pad 33 can be made of the same high-density high-temperature resistant elastic material, which can seal the side of the thermal insulation elastic strip 32 that contacts the hollow cavity 312, preventing pressurized fluid from seeping out from the thermal insulation elastic strip 32 with higher porosity. In some embodiments, the porosity of the thermal insulation elastic strip 32 is 40%-90%, and the porosity of the first high-temperature resistant elastic pad 33 and the second high-temperature resistant elastic pad 34 is ≤40%. In some embodiments, the high temperature resistance of the first high temperature resistant elastic pad 33 and the second high temperature resistant elastic pad 34 is ≤2000℃, the high temperature resistance of the heat insulation elastic strip 32 is ≤3500℃, the thickness of the first high temperature resistant elastic pad 33 and the second high temperature resistant elastic pad 34 is 0.1~200mm, and the thickness of the heat insulation elastic strip 32 is 0.1~300mm. The specific thickness can be reasonably selected according to the actual welding conditions.

[0053] In some embodiments, the elastic sealing ring 2 includes an insert ring 21 that fits into an assembly ring groove 14 on the bottom end of the vacuum shroud 1. The assembly ring groove 14 is a constricted groove (i.e., the width of the groove opening is smaller than the width of the groove body). The cross-sectional shape and size of the insert ring 21 match the cross-sectional shape and size of the assembly ring groove 14. Specifically, the cross-section of the assembly ring groove 14 is an inverted trapezoid with a larger top and a smaller bottom, and correspondingly, the cross-section of the insert ring 21 is also an inverted trapezoid with a larger top and a smaller bottom.

[0054] In this technical solution, the embedded ring 21 of the elastic sealing ring 2 is adapted to the inverted trapezoidal groove structure of the assembly ring groove 14 of the vacuum shroud 1, thereby objectively forming a wedge-shaped anti-detachment structure. For example, the narrowing structure of the assembly ring groove 14 forms a mechanical anchoring of the top embedded part of the elastic sealing ring 2, effectively reducing the probability of the elastic sealing ring 2 detaching from the vacuum shroud 1 under the action of internal and external pressure difference during the welding process. At the same time, it can also effectively reduce the probability of circumferential movement or radial rolling caused by uneven friction between the elastic sealing ring 2 and the workpiece to be welded during the welding process, ensuring that the vacuum degree is maintained stably during the welding process.

[0055] See details Figure 6 As shown, in some embodiments, a filling ring cavity 211 is formed inside the insert ring 21. The filling ring cavity 211 extends along the annular direction of the insert ring 21 and is used to fill the filling ring cavity 211 with a pressurized fluid. The pressurized fluid can be gaseous, liquid, or even solid particles that can be applied under the high-temperature conditions. In principle, it is sufficient that the fluid filling the filling ring cavity 211 can cause outward extrusion deformation of the outer wall of the filling ring cavity 211.

[0056] In this technical solution, by providing a filling ring cavity 211 in the insert ring 21, the filling ring cavity 211 can be filled with a corresponding pressure fluid, so that it can expand and deform under the outward squeezing action of the pressure fluid, thereby improving the connection reliability and stability of the insert ring 21 in the assembly ring groove 14. It is understandable that when the aforementioned insert ring 21 adopts a solid structure, in order for its wedge-shaped structure, which is larger at the top and smaller at the bottom, to be smoothly inserted into the assembly ring groove 14 of the constricted structure in an interference fit, the difference between the large size of the insert ring 21 and the small size of the assembly ring groove 14 should not be too large. Generally, the vacuum cover 1 needs to be heated when assembling the elastic sealing ring 2. By forming a hollow structure, namely the aforementioned filling ring cavity 211, in the insert ring 21, it can be ensured that the filling ring cavity 211 is hollow before assembly. Since there is no pressurized fluid in the filling ring cavity 211, the insert ring 21 has a greater deformation capacity (it can shrink in size under external force) and is more easily inserted into the assembly ring groove 14. After being inserted into the assembly ring groove 14, pressurized fluid is then filled into the filling ring cavity 211 to improve the deformation resistance of the insert ring 21, thereby making it closely matched with the assembly ring groove 14 and improving the anti-dislodgement effect of the elastic sealing ring 2.

[0057] It is understood that the pressure fluid in the aforementioned filled annular cavity 211 can be the same as or different from the pressure fluid in the aforementioned hollow cavity 312. In some preferred embodiments, the pressure fluid in the aforementioned filled annular cavity 211 is the same as the pressure fluid in the aforementioned hollow cavity 312, that is, both use cooling water as the pressure fluid. In this case, the filled annular cavity 211 and the hollow cavity 312 can share a set of the aforementioned active cooling circulation components, which can simplify the structural design and reduce manufacturing costs. However, in terms of the specific circulation flow path design, the pressure requirements of the pressure fluid in the filled annular cavity 211 and the hollow cavity 312 are different, and they should be designed to form independent pressure control designs through corresponding circulation flow paths.

[0058] In some embodiments, the weld sealing strip assembly 3 has two symmetrical sections about the cover hole 11, which makes the local vacuum laser welding device suitable for linear reciprocating welding conditions and improves the versatility of the device.

[0059] The aforementioned local vacuum laser welding device uses the following method for welding:

[0060] Step 1: Clean the workpiece to be welded. Before welding, assemble the workpiece to be welded as required and clean the surface oil. Then assemble it on the welding platform.

[0061] Step 2: Prepare the vacuuming components and connect the vacuuming components to the vacuum port 62 (for example, connect them to an external vacuum pump through a vacuum bellows).

[0062] Step 3: Based on the welding process parameters and the resulting weld reinforcement, select a sealing structure of appropriate size (mainly the thickness and other parameters of the aforementioned weld sealing strip assembly 3).

[0063] Step 4: Control the vacuum pumping component to operate and pump vacuum. Once the vacuum level meets the welding requirements, start welding. During the process, maintain the pressure fluid in the active cooling circulation component and the aforementioned hollow cavity 312 at a preset pressure.

[0064] Step 5: Welding completed, turn off the welding torch and vacuum pump.

[0065] In some embodiments, during the local vacuum laser welding of metallic materials, the welding power is 0.01~200kW, the welding speed is 0.01~5m / min, and the resulting weld reinforcement is 0.1~30mm.

[0066] In the process of local vacuum laser welding of thick plate components, the "sandwich" local vacuum composite sealing device of the present invention is used. The sealing structure as a whole must have excellent high temperature resistance and heat insulation performance to effectively prevent vacuum leakage. It can make the sealing material and the workpiece surface completely fit together, ensure the stability of the local vacuum cavity, and achieve high-quality welding of components, providing a new method for the engineering application of vacuum laser welding.

[0067] The design mechanism of the method of this invention is as follows:

[0068] The dense, elastic surface layers placed on the inner and outer sides (i.e., the aforementioned first and second high-temperature resistant elastic gaskets), with their significant compressibility, act as an adaptive sealing interface. Under the action of clamping force, they can fully conform to the contour of the weld reinforcement and the microscopic irregularities of the workpiece surface, undergoing elastic or plastic deformation to fill the gaps and form the first airtight barrier. Their dense characteristics minimize the leakage path of gas through the material body. The high-porosity thermal insulation layer sandwiched in the middle (i.e., the aforementioned thermal insulation elastic strip 32) is dedicated to thermal protection. Its porous structure contains a large amount of still air, which can effectively block the intense radiant and conductive heat from the weld pool, constructing a stable thermal barrier inside the sealing body. This design is crucial: it ensures that the actual operating temperature of the lower dense surface layer near the high-temperature zone is significantly reduced, thus enabling it to maintain its sealing function within a safe range for a long time; at the same time, it also protects the upper sealing material and the outer auxiliary sealing elements from thermal damage, maintaining the structural integrity of the entire sealing system at high temperatures.

[0069] In the aforementioned sandwich multi-layer sealing structure, each layer is bonded together with high-temperature resistant adhesive to form a whole, producing a synergistic reinforcement effect. The rigid insulation layer provides backing support for the flexible surface layer, preventing it from becoming unstable or collapsing under vacuum negative pressure; while the flexible surface layer absorbs mechanical stress through deformation, protecting the insulation layer from excessive compression. This configuration effectively separates the mechanical stress from the heat load transmission path. Finally, this "sandwich" composite sealing structure works in conjunction with the outer annular elastic seal (i.e., the aforementioned elastic sealing ring 2) to form a partitioned sealing, primary and secondary coordinated composite sealing system, which not only overcomes the high-temperature sealing problem in the weld area but also ensures the sealing reliability and economy of the rest of the system.

[0070] This invention significantly improves the sealing performance and engineering applicability of partial vacuum laser welding through synergistic innovation in structure, materials, and processes. Its most prominent advantage lies in the combination of superior high-temperature resistance and long-lasting sealing reliability under high-temperature environments, fundamentally solving the long-standing technical bottleneck of partial vacuum laser welding. Through a unique "sandwich" composite sealing structure design, this invention imbues the core high-temperature protection function into a high-porosity thermal insulation layer. This layer effectively blocks welding temperatures exceeding 1000℃, constructing a stable thermal barrier for the entire sealing system. Under this protection, the dense, elastic surface layers on both the inner and outer sides can operate within a safe temperature range, maintaining the inherent temperature resistance of the material. The material is no longer directly exposed to extreme thermal shock, thus completely avoiding the softening, ablation, and failure problems that are common in traditional polymer sealing materials, achieving stable high-temperature tolerance throughout the entire laser welding cycle. Furthermore, this invention demonstrates the ability to dynamically maintain a seal under continuous high-temperature conditions. The highly elastic, dense surface layer not only adapts to the weld reinforcement and workpiece surface morphology during initial compression but also maintains sufficient elasticity and contact pressure during the welding thermal cycle, actively compensating for microscopic gaps that may arise from thermal expansion and contraction. Simultaneously, the intermediate heat insulation layer ensures the dimensional stability of the entire sealing structure, preventing overall softening and deformation due to high temperatures. This synergistic stability, coupled with the circulation of pressurized fluid in the hollow cavity 312 within the aforementioned strip-shaped elastic body 31, further eliminates temperature rise in related components, ensuring that the local vacuum cavity maintains an effective vacuum seal throughout the entire process from welding to cooling, significantly improving reliability.

[0071] In addition to its core advantage of high-temperature sealing, this invention also boasts broad process adaptability and excellent economic efficiency. Its sealing interface can adapt to various joint types and surface conditions, reducing the stringent requirements for workpiece preparation and broadening the process window. The entire device has a simple structure, is easy to assemble and adjust, requires no complex auxiliary cooling system, and has low maintenance and replacement costs. Compared to constructing large vacuum chambers, this invention achieves a high-quality local vacuum environment with extremely low cost and energy consumption, providing a practical and economical solution for high-efficiency welding of high-end materials in aerospace, new energy vehicles, and other fields, demonstrating broad prospects for industrial application.

[0072] The technical solution of the present invention will be described below with reference to several embodiments and comparative examples.

[0073] Example 1

[0074] A 30mm thick stainless steel plate was selected. Before welding, dust and oil were removed from the surface of the plate to ensure cleanliness. A sandwich composite sealing device (i.e., the aforementioned sealing structure, containing the aforementioned hollow cavity 312 filled with pressurized fluid) was used to adhere to the plate surface, and a vacuum environment was created using a vacuum pump (i.e., the aforementioned vacuum pumping component). When the vacuum level was maintained at 10 Pa, a vacuum laser welding experiment was conducted. Selected welding parameters: welding power of 8kW and welding speed of 0.5m / min. Selected sealing device parameters: the thickness of both dense elastic surface layers (i.e., the aforementioned first and second high-temperature resistant elastic gaskets) was 20mm, and the thickness of the high-porosity heat insulation layer (i.e., the aforementioned heat-insulating elastic strip 32) was 30mm.

[0075] Technical Effects and Analysis: Through the aforementioned welding process, localized vacuum laser welding of thick stainless steel plates was achieved, resulting in a weld surface morphology as shown in the figure. Figure 7 As shown in (a), the figure demonstrates that high-quality welding of steel was achieved using localized vacuum laser welding, with no welding defects on the weld surface and the vacuum level consistently maintained around 10 Pa. This fully proves that the dense elastic surface layer on the high-temperature side close to the workpiece (i.e., the aforementioned first high-temperature resistant elastic gasket 33) can still tightly adhere to the plate surface and weld area while withstanding the welding thermal shock, without causing leakage points due to high-temperature ablation. Moreover, the high-porosity heat insulation layer in the middle (i.e., the aforementioned heat insulation elastic strip 32) effectively blocks the transmission of welding high temperature to the upper part of the sealing device and the vacuum pump, protecting the key components of the vacuum system and maintaining the performance integrity of the sealing material, thus achieving a dual mechanism of high-temperature isolation and morphological fit.

[0076] Comparative Example 1

[0077] A 30mm thick stainless steel sheet was selected. Before welding, dust and oil were removed from the surface of the sheet to ensure cleanliness. A localized vacuum high-temperature resistant elastic gasket was applied to the sheet surface, and a vacuum environment was created using a vacuum pump. Once the vacuum level was maintained at 10 Pa, a vacuum laser welding experiment was conducted. Selected welding parameters: welding power 8kW, welding speed 0.5m / min. Selected sealing device parameters: dense elastic surface layer thickness 70mm.

[0078] Technical effects and analysis: Through the aforementioned welding process, the surface morphology of the weld seam in thick stainless steel plates is as follows: Figure 7 As shown in (b), although the local vacuum laser welding technology achieved the welding of thick stainless steel plates, the molten pool fluctuated significantly during the process, resulting in severe metal spatter. The vacuum level increased from the initial 10 Pa to 1000 Pa, leading to severe oxidation of the weld surface. The decrease in vacuum level directly confirmed the sealing failure and gas leakage. The leakage caused residual air to enter the welding zone, causing surface oxidation of the weld and disrupting the suppression effect of the local vacuum environment on plasma plume. This resulted in increased plume expansion, which not only contaminated the protective lens but also further weakened the weld penetration due to laser energy scattering and attenuation. Therefore, in the welding process of a single, dense, elastic surface sealing structure, the surface material is directly exposed to extreme high temperatures, making it prone to localized ablation or performance degradation. A stable local vacuum environment cannot be maintained, making it difficult to guarantee welding quality.

[0079] Comparative Example 2

[0080] A 30mm thick stainless steel sheet was selected. Before welding, dust and oil were removed from the surface of the sheet to ensure cleanliness. A localized vacuum single high-porosity insulation layer was applied to the surface of the sheet, and a vacuum environment was created using a vacuum pump. Once the vacuum level was maintained at 10 Pa, a vacuum laser welding experiment was conducted. The selected welding parameters were: welding power of 8kW, welding speed of 0.5m / min, and insulation layer thickness of 70mm.

[0081] Technical effects and analysis: Through the aforementioned welding process, the surface morphology of the weld seam in thick stainless steel plates is as follows: Figure 7As shown in (c), although the local vacuum laser welding technology achieved the welding of thick stainless steel plates, the process resulted in severe metal spatter, with the vacuum level increasing from the initial 10 Pa to 10000 Pa. While the 70mm thick insulation layer possesses good high-temperature insulation performance and can block the welding heat source to some extent, its material itself has high porosity and a loose surface, lacking a dense sealing interface. Under compression, its fit with the weld reinforcement is poor, failing to effectively fill the gaps formed by minor surface irregularities, thus leaving physical channels for gas leakage. Furthermore, this single structure may lack sufficient elasticity to adapt to the dynamic changes in workpiece morphology caused by thermal cycling during welding, leading to localized loss of sealing pressure.

[0082] Example 2

[0083] A 150mm thick stainless steel plate was selected. Before welding, dust and oil were removed from the plate surface to ensure cleanliness. A sandwich composite sealing device was used to adhere to the plate surface, and a vacuum environment was created using a vacuum pump. Vacuum laser welding was conducted when the vacuum level was maintained at 10 Pa. Selected welding parameters: welding power of 50kW and welding speed of 0.5m / min. Selected sealing device parameters: the porosity of the two dense elastic surface layers (i.e., the aforementioned first and second high-temperature resistant elastic gaskets) was 20%; the porosity of the high-porosity insulation layer (i.e., the aforementioned insulation elastic strip 32) was 80%.

[0084] Technical Effects and Analysis: The welding process described above achieved localized vacuum laser welding of thick stainless steel plates, with no welding defects on the weld surface and the vacuum level consistently maintained around 10 Pa. Under extremely high heat input conditions, the dense, elastic surface layer on the high-temperature side close to the workpiece maintained its structural integrity and closely adhered to the plate surface and the dynamically formed weld area, without any leakage channels caused by high-temperature ablation, softening, or decomposition. The intermediate high-porosity insulation layer played a crucial thermal barrier role; its low-density, high-porosity structure effectively blocked the transmission of welding high temperatures to the upper part of the sealing device and the vacuum system, thereby protecting the performance stability of the vacuum sealing interface and pump components.

[0085] Comparative Example 3

[0086] A 150mm thick stainless steel sheet was selected. Before welding, dust and oil were removed from the surface of the sheet to ensure cleanliness. A sandwich composite sealing device was used to adhere to the sheet surface, and a vacuum environment was created using a vacuum pump. Once the vacuum level was maintained at 10 Pa, a vacuum laser welding experiment was conducted. Selected welding parameters: welding power 50kW, welding speed 0.5m / min. Selected sealing device parameters: the porosity of the two dense elastic surface layers was 50%; the porosity of the high-porosity insulation layer was 95%.

[0087] Technical Effects and Analysis: While localized vacuum laser welding technology enabled the welding of thick stainless steel plates, it resulted in severe metal spatter during the process, with the vacuum level increasing from the initial 10 Pa to 1000 Pa. This is primarily due to the fact that despite the composite structure, the high porosity (up to 50%) of the dense, elastic surface layer means its density is relatively insufficient. Under the intense thermal shock and metal vapor impact of 50kW ultra-high power laser welding, it may be more prone to microscopic damage or leakage. Simultaneously, while the extremely high porosity (95%) of the intermediate insulation layer provides excellent thermal insulation, it may also weaken its mechanical support function as a structural layer. Under compression and thermal stress, it is more susceptible to compressive deformation, affecting the uniform transmission and maintenance of the overall sealing pressure. This macroscopic mismatch amplifies the potential microscopic sealing deficiencies caused by the high porosity of the material, collectively forming a significant leakage channel at the weld seam height profile.

[0088] It will be readily understood by those skilled in the art that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0089] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. A local vacuum laser welding apparatus, characterized in that, The system includes a vacuum hood (1) and a sealing structure. The sealing structure includes an elastic sealing ring (2) and a weld sealing strip assembly (3). The vacuum hood (1) has a hood hole (11) that is opposite to the workpiece to be welded. The elastic sealing ring (2) is connected to the bottom end face of the vacuum hood (1) and surrounds the hood hole (11). A fixing groove (20) is formed on the bottom end face of the elastic sealing ring (2). The weld sealing strip assembly (3) is snapped into the fixing groove (20). The weld sealing strip assembly (3) encloses... The assembly includes a strip-shaped elastic body (31), a heat-insulating elastic strip (32), and a first high-temperature resistant elastic pad (33) arranged sequentially along the direction close to the workpiece to be welded. The heat-insulating elastic strip (32) is connected to the bottom end face of the strip-shaped elastic body (31), and the first high-temperature resistant elastic pad (33) is connected to the bottom end face of the heat-insulating elastic strip (32) and can adhere to the outer wall of the weld by its own deformation. The porosity of the heat-insulating elastic strip (32) is higher than that of the first high-temperature resistant elastic pad (33).

2. The local vacuum laser welding apparatus according to claim 1, characterized in that, The strip-shaped elastic body (31) has a hollow cavity (312) recessed toward the side away from the workpiece to be welded, the heat-insulating elastic strip (32) is sealed to the opening of the hollow cavity (312), the hollow cavity (312) is filled with pressurized fluid; and / or, an auxiliary positioning groove (13) is formed on the bottom end surface of the vacuum shroud (1) and engages with the top end surface of the strip-shaped elastic body (31).

3. The local vacuum laser welding apparatus according to claim 2, characterized in that, It also includes an active cooling circulation component, which includes a refrigeration component (41), a circulation pressurizing pump (42), a return pipe (43), and an inlet pipe (44). The return pipe (43) and the inlet pipe (44) can both communicate with the hollow cavity (312). The pressurized fluid is cooling water. The circulation pressurizing pump (42) is used to form a pressure circulation of the cooling water between the refrigeration component (41) and the hollow cavity (312) through the return pipe (43) and the inlet pipe (44).

4. The local vacuum laser welding apparatus according to claim 3, characterized in that, Two filling tubes (313) are formed on the strip-shaped elastic body (31) at both ends of its length. The two filling tubes (313) are respectively located on the inner and outer sides of the elastic sealing ring (2). The active cooling circulation component is circulated with the hollow cavity (312) through each of the filling tubes (313). A positioning through hole (12) is formed on the vacuum cover (1). Each of the filling tubes (313) is inserted into the positioning through hole (12) in a corresponding manner to realize the detachable connection between the weld sealing strip assembly (3) and the vacuum cover (1).

5. The local vacuum laser welding apparatus according to claim 4, characterized in that, The filling tube (313) is press-fitted with the positioning through hole (12), and an anti-slip sealing structure (314) is formed between the mating wall surfaces of the filling tube (313) and the positioning through hole (12); and / or, the inlet tube (44) is connected to the filling tube (313) located inside the elastic sealing ring (2).

6. The local vacuum laser welding apparatus according to claim 5, characterized in that, The anti-slip sealing structure (314) includes multiple first anti-detachment rings formed on the outer wall of the filling tube (313) and multiple second anti-detachment rings formed on the inner wall of the positioning through hole (12). Each first anti-detachment ring and each second anti-detachment ring extends around the circumference of the positioning through hole (12), and the depth directions of each positioning through hole (12) are staggered to form a concave-convex fit.

7. The local vacuum laser welding apparatus according to claim 3, characterized in that, The weld sealing strip assembly (3) further includes a second high-temperature resistant elastic gasket (34), which is located between the heat-insulating elastic strip (32) and the strip-shaped elastic body (31); and / or, the elastic sealing ring (2) includes an insert ring (21) fitted into an assembly ring groove (14) on the bottom end of the vacuum shroud (1), the assembly ring groove (14) being a constricted groove, and the cross-sectional shape of the insert ring (21) matching the cross-sectional shape of the assembly ring groove (14).

8. The local vacuum laser welding apparatus according to claim 7, characterized in that, A filling annular cavity (211) is formed within the insert ring (21), the filling annular cavity (211) extends along the annular direction of the insert ring (21) and is used to fill pressure fluid.

9. The local vacuum laser welding apparatus according to claim 7, characterized in that, The porosity of the heat-insulating elastic strip (32) is higher than that of the second high-temperature resistant elastic pad (34); and / or, the porosity of the heat-insulating elastic strip (32) is 40%-90%, and the porosity of the first high-temperature resistant elastic pad (33) and the second high-temperature resistant elastic pad (34) is ≤40%.

10. The local vacuum laser welding apparatus according to claim 3, characterized in that, The weld sealing strip assembly (3) has two symmetrical sections about the cover hole (11).

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