Local vacuum laser welding device and welding method thereof

Abstract

This invention provides a local vacuum laser welding device and method, belonging to the field of vacuum laser welding equipment design technology. The device includes 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 surface of the vacuum hood and surrounds the hood's opening. A fixing groove is formed on the bottom surface of the elastic sealing ring to hold the weld sealing strip assembly. The weld sealing strip assembly includes a strip-shaped elastic body and a high-temperature resistant elastic gasket. A contoured groove is formed on the bottom surface of the strip-shaped elastic body, extending through both ends of the strip-shaped elastic body. The high-temperature resistant elastic gasket is connected to the groove wall and can conform to the outer wall surface of the weld seam through its own deformation. This invention enables precise, gapless fitting between the weld sealing strip assembly and the outer wall surface of the weld reinforcement during the welding process, ensuring that the vacuum level 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, specifically relating to a local vacuum laser welding device and its welding method. 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 and welding method, which can overcome the shortcomings of the existing local vacuum welding device, which has insufficient fit between the sealing structure and the weld reinforcement surface contour, resulting in the vacuum degree not being maintained stably during the welding process and reducing the quality of vacuum laser welding.

[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 and a high-temperature resistant elastic gasket arranged sequentially along the direction close to the workpiece to be welded. A contoured groove is formed on the bottom end face of the strip-shaped elastic body. The contoured groove extends through both ends of the strip-shaped elastic body along the length of the weld. The high-temperature resistant elastic gasket is connected to the groove wall of the contoured groove and can conform to the outer wall surface of the weld by its own deformation.

[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 high-temperature resistant elastic gasket is sealed to the opening of the hollow cavity, and the hollow cavity is filled with pressurized fluid; an auxiliary positioning groove is formed on the bottom end face of the vacuum shroud to engage 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, the strip-shaped elastic body has two filling tubes formed 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 has positioning through holes, and 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; 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, an elastic thermally conductive layer is provided between the high-temperature resistant elastic gasket and the contoured groove; the elastic sealing ring includes an insert ring that is 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 weld seal assembly has two symmetrical sections about the cover hole.

[0018] The present invention also provides a welding method using the above-described local vacuum laser welding apparatus, comprising the following steps:

[0019] Position the workpiece to be welded after cleaning;

[0020] Select a weld sealing strip assembly that corresponds to the weld reinforcement height of the workpiece to be welded and assemble the weld sealing strip assembly with the vacuum hood, and control the operation of the active cooling circulation component so that the pressure fluid in the hollow cavity reaches the preset pressure;

[0021] The local vacuum laser welding device is started to weld the workpiece to be welded. During the welding process, the real-time pressure in the hollow cavity is detected and the circulating pressure pump is adjusted to ensure that the real-time pressure is maintained at the preset pressure.

[0022] The local vacuum laser welding device and welding method provided by the present invention have the following beneficial effects:

[0023] By engaging a weld sealing strip assembly aligned with the weld length direction on the bottom end face of an elastic sealing ring surrounding the cover hole, and setting a contoured groove on the bottom end face of the weld sealing strip assembly that resembles the shape and size of the outer wall surface of the weld reinforcement, and further setting a high-temperature resistant elastic gasket on the groove wall, a precise and gapless fit between the weld sealing strip assembly and the outer wall surface (contour) of the weld reinforcement can be achieved during the welding process. This ensures that the vacuum degree at the cover hole is stably maintained at a preset value during the welding process, improving the quality of vacuum laser welding. It is worth emphasizing that the aforementioned high-temperature resistant elastic gasket utilizes its own elastic deformation to achieve adaptive compensation fitting for changes in weld size, resulting in a higher compensation and filling response rate compared to other methods (such as filling the outer wall surface of the weld with sealing material). Attached Figure Description

[0024] 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.

[0025] Figure 1 This is a three-dimensional structural schematic diagram of the local vacuum laser welding device of the present invention in one embodiment;

[0026] Figure 2 This is an exploded three-dimensional structural diagram of the local vacuum laser welding device of the present invention in another embodiment;

[0027] Figure 3 yes Figure 2 A three-dimensional structural diagram of the weld sealing strip assembly in the image;

[0028] Figure 4 yes Figure 3 A schematic cross-sectional view of the weld seal strip assembly in the diagram;

[0029] 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.

[0030] Figure 6 yes Figure 2 A partial cross-sectional structural diagram of the assembly of the elastic sealing ring and the vacuum hood;

[0031] Figure 7The 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 contour groove of the present invention but adopts a high-temperature resistant elastic gasket.

[0032] The attached figures are labeled as follows:

[0033] 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; 30. Contouring groove; 31. Strip-shaped elastic body; 312. Hollow cavity; 313. Filling tube; 314. Anti-slip sealing structure; 32. High temperature resistant elastic gasket; 33. Elastic heat-conducting layer; 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

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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-shaped elastic body 31 and the high-temperature resistant elastic pad 32 are arranged sequentially from top to bottom in the indicated orientation. A contoured groove 30 is formed on the bottom surface of the strip-shaped elastic body 31. The specific structural shape of the contoured groove 30 is similar to the outer wall surface of the corresponding weld reinforcement. The specific shape and size can be reasonably selected and matched according to the actual welding conditions. The contoured groove 30 extends along the length of the weld (i.e.,...). Figure 1 (In the left and right directions shown) it extends through both ends of the length of the strip elastic body 31, and the high temperature resistant elastic pad 32 is connected to the groove wall of the contoured groove 30 and can fit against the outer wall of the weld by its own deformation.

[0039] In this technical solution, a weld sealing strip assembly 3, which is aligned with the weld length direction, is snapped onto the bottom end face of an elastic sealing ring 2 surrounding the cover hole 11. A contoured groove 30, similar in shape and size to the outer wall of the weld reinforcement, is provided on the bottom end face of the weld sealing strip assembly 3. Furthermore, a high-temperature resistant elastic gasket 32 ​​is further provided on the groove wall of the contoured groove 30. This enables precise and gapless fitting between the weld sealing strip assembly 3 and the outer wall (contour) of the weld reinforcement during the welding process. This ensures that the vacuum degree at the cover hole 11 is stably maintained at a preset value during the welding process, thereby improving the quality of vacuum laser welding. It is worth emphasizing that the aforementioned high-temperature resistant elastic gasket 32 ​​utilizes its own elastic deformation to achieve adaptive compensation fitting for changes in weld size. Compared with other methods (such as filling the outer wall of the weld with sealing material), the compensation and filling response rate is higher. 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.

[0040] The aforementioned high-temperature resistant elastic gasket 32, as a component in direct contact with the weld, acts as a barrier against the high temperature of direct 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 high-temperature resistant elastic gasket 32 ​​can also effectively block the transfer of welding heat from the weld to the elastic sealing ring 2 on it due to its excellent thermal stability and ablation resistance, preventing the elastic sealing ring 2 from failing due to softening or decomposition at high temperatures. The strip-shaped elastic body 31 can provide high elasticity to ensure that the high-temperature resistant elastic gasket 32 ​​can reliably and efficiently adapt to and compensate for changes in the shape of the outer wall of the weld. At the same time, it can also have a certain rigidity to ensure the structural stability and reliability of the entire weld sealing strip assembly 3.

[0041] Furthermore, it should be noted that the two ends of the aforementioned high-temperature resistant elastic gasket 32 ​​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 high-temperature resistant elastic gasket 32 ​​(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.

[0042] 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 2The 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 elastic gasket 32 ​​using a high-temperature resistant adhesive. In a preferred embodiment, the hollow cavity 312 has an opening facing the workpiece to be welded. In this case, the high-temperature resistant elastic gasket 32 ​​is sealed to the opening of the hollow cavity 312. That is, the hollow cavity 312 is formed by the high-temperature resistant elastic gasket 32 ​​and the strip elastic body 31 together to form a sealed cavity. In this case, the high-temperature resistant elastic gasket 32 ​​can exist as the bottom wall surface of the strip elastic body 31. The aforementioned contoured groove 30 is formed on the high-temperature resistant elastic gasket 32. The hollow cavity 312 is filled with pressurized fluid.

[0043] 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 high-temperature resistant elastic pad 32, thereby improving the deformation ability of the high-temperature resistant elastic pad 32 at different weld positions.

[0044] 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 more stable, preventing the weld sealing strip assembly 3 from detaching or causing vacuum leakage due to 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.

[0045] See details Figure 2As shown, in some embodiments, the local vacuum laser welding apparatus further includes an active cooling circulation component (not labeled 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 therein. 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.

[0046] In this technical solution, cooling water is used as the aforementioned pressure fluid. Its positive pressure enables the outward expansion and deformation of the high-temperature resistant elastic gasket 32, ensuring efficient deformation and seamless contact with different locations on the weld outer wall to guarantee sealing. Simultaneously, an active cooling circulation component circulates and cools the cooling water, significantly reducing the temperature rise of the high-temperature resistant elastic gasket 32, the strip-shaped elastic body 31, and the vacuum chamber 1. This simplifies material selection for related components. Furthermore, due to active cooling, the lower temperature limit of the high-temperature resistant elastic gasket 32 ​​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 cooling requirements and the pressure requirements of the pressure fluid.

[0047] In some embodiments, the strip-shaped elastic body 31 has two filling tubes 313 formed 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 has 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] In some embodiments, an elastic heat-conducting layer 33 is provided between the high-temperature resistant elastic pad 32 and the contoured groove 30, so as to more efficiently guide the heat on the high-temperature resistant elastic pad 32 into the hollow cavity 312 and exchange heat with the pressure fluid therein, effectively reducing the temperature rise of the high-temperature resistant elastic pad 32. In other feasible embodiments, the opposite sides of the aforementioned elastic heat-conducting layer 33 are reliably connected to the high-temperature resistant elastic pad 32 by a high-temperature resistant adhesive and a strip elastic body 31. In order to further improve the heat conduction effect of the elastic heat-conducting layer 33, it can be made of a composite material containing metal particles.

[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 allows the local vacuum laser welding device to be used in linear reciprocating welding. It is understood that, due to the design of the aforementioned hollow cavity 312, on the side where no weld is formed, the contoured groove 30 of the weld sealing strip assembly 3 will be in a state of contact with the plane of the workpiece to be welded under the action of the pressurized fluid (objectively a plane rather than a groove), thereby ensuring the sealing of the side without a weld.

[0059] According to an embodiment of the present invention, a welding method using the above-described local vacuum laser welding apparatus is also provided, comprising the following steps:

[0060] After cleaning the workpiece to be welded, position it. Specifically, before welding, assemble the workpiece to be welded as required, clean the surface oil, and then assemble it on the welding platform.

[0061] Select the weld sealing strip assembly 3 corresponding to the weld reinforcement height of the workpiece to be welded and assemble the weld sealing strip assembly 3 with the vacuum chamber 1 (select the groove width and groove depth of the groove 30 on the strip elastic body 31 or the high temperature resistant elastic pad 32 and the corresponding thickness, the temperature resistance of the high temperature adhesive bonding the two, etc. according to the welding process parameters and the resulting weld reinforcement height), control the operation of the active cooling circulation component so that the pressure fluid in the hollow cavity 312 reaches the preset pressure. It is understood that the corresponding vacuum pumping component should also be turned on to form the target vacuum degree in the vacuum chamber 1.

[0062] After the vacuum level in the vacuum chamber 1 reaches the target value, the local vacuum laser welding device is started to weld the workpiece to be welded. During the welding process, the real-time pressure in the hollow cavity 312 is detected and the circulating pressure pump 42 is adjusted to ensure that the real-time pressure is maintained at the preset pressure. This is to prevent excessive real-time pressure from causing excessive friction between the weld sealing strip assembly 3 and the outer wall of the weld, which would accelerate component wear, and insufficient real-time pressure from causing untimely deformation and dimensional compensation of the high-temperature resistant elastic gasket 32 ​​in the weld sealing strip assembly 3, which would lead to vacuum leakage. After welding is completed, the welding device and vacuum pump are turned off.

[0063] In some embodiments, during the local vacuum laser welding of metal materials, the welding power is 0.01-200 kW, the welding speed is 0.01-5 m / min, and the weld reinforcement is 0.1-30 mm. During the local vacuum laser welding of metal materials, the groove depth (i.e., the aforementioned contoured groove 30) of the high-temperature resistant elastic pad 32 is 0.1-50 mm, and the groove width is 0.1-100 mm. The thickness of the strip elastic body 31 is 0.1-60 mm.

[0064] The core of this invention's design mechanism lies in the synergistic effect of a contour-following sealing structure, a composite high-temperature resistant system, and parameter adaptation to systematically solve the sealing technology bottleneck in localized vacuum laser welding. For the unique arc-shaped or fish-scale pattern contour of the weld reinforcement surface, a high-temperature resistant elastic gasket is set with a precisely matched contour-following groove facing the weld side, achieving geometric conformity between the sealing interface and the weld shape, thereby eliminating leakage gaps caused by contour mismatch at the structural level. To cope with the instantaneous high-temperature environment in the welding area, a double-layer functional structure is adopted, using an elastic elastomer sealing material as the matrix and a high-temperature resistant elastic gasket composite on the surface, along with an elastic thermally conductive layer disposed between the high-temperature resistant elastic gasket and the elastomer sealing material.

[0065] The elastomeric sealing material (i.e., the aforementioned strip-shaped elastic body 31) provides the necessary structural elasticity and compressive resilience to ensure initial sealing. The high-temperature resistant elastic gasket is firmly attached to the outer wall of the contour groove by a high-temperature resistant adhesive, directly facing high-temperature heat radiation and molten pool splash. With its excellent thermal stability and ablation resistance, it effectively blocks heat transfer to the internal elastomeric sealing material, preventing the sealing body from failing due to high-temperature softening or decomposition. Through the elastic heat-conducting layer and its external cooling connection set at the sealing interface, a closed cooling channel (i.e., the aforementioned hollow cavity 312) is pre-installed inside. During welding, the cooling medium (i.e., the aforementioned pressure fluid) of the external cooling system (i.e., the aforementioned active cooling circulation component) circulates in this channel, thereby achieving efficient and uniform active cooling inside the structure directly involved in sealing and bonding. This achieves active and efficient heat removal from welding, fundamentally avoiding thermal failure of the elastomeric material. The three components complement and synergize under high-temperature conditions, maintaining a continuous tight fit between the sealing surface and the workpiece surface, and significantly improving the overall thermal durability of the structure. Furthermore, the device allows for matching adjustments to the width and depth of the contour groove and the thickness of the elastomeric sealing material based on welding power, speed, and expected weld size. Through parameter optimization, the sealing structure dynamically adapts to different welding processes and weld morphologies, thus maintaining the stability and integrity of the local vacuum cavity under varying operating conditions. In summary, this invention, through the integrated design of a triple mechanism of "structural contouring - material temperature resistance - adjustable parameters (adaptive deformation adjustment)," fundamentally overcomes the defects of traditional sealing methods, such as poor fit, high-temperature failure, and insufficient reliability. This provides crucial technical support for achieving high-quality, high-reliability local vacuum laser welding of thick plate components.

[0066] Furthermore, the local vacuum laser welding device of this invention features a practical and easy-to-maintain structure. The sealing components can be flexibly customized according to the weld morphology, and quick installation and replacement are achieved through positioning grooves (i.e., the aforementioned positioning through-hole 12 and auxiliary positioning groove 13), significantly improving assembly efficiency and operational convenience. It also boasts strong process compatibility; the sealing structure does not affect the laser beam path or welding process, and can be directly integrated with existing local vacuum welding systems without complex modifications, facilitating widespread adoption and practical application. In summary, this invention offers significant advantages in terms of fit, temperature resistance, sealing reliability, and ease of use, providing a practical sealing solution for high-quality, high-efficiency local vacuum laser welding.

[0067] The technical solution of the present invention will be described below with reference to several embodiments and comparative examples.

[0068] Example 1

[0069] A 50mm thick stainless steel plate was selected. Before welding, dust and oil were removed from the plate surface to ensure cleanliness. A local vacuum composite sealing device was used to adhere to the plate surface, and a vacuum environment was created using a vacuum pump. The composite sealing assembly included a vacuum shroud and a high-temperature resistant elastic gasket (the aforementioned high-temperature resistant elastic gasket 32) embedded within it, conforming to the weld contour. The high-temperature resistant elastic gasket had a contoured groove (the aforementioned contoured groove 30) on the side facing the weld. An elastic thermally conductive layer and an elastomeric sealing material (the aforementioned strip-shaped elastic body 31) were fixedly bonded to the outer wall of the contoured groove using a high-temperature resistant adhesive. The elastomeric sealing material contained a hollow cavity for filling with pressurized fluid, which circulated during welding to achieve cooling (the aforementioned hollow cavity 312). Vacuum laser welding experiments were conducted when the vacuum level was maintained at 10 Pa. The selected welding parameters were: welding power of 10 kW and welding speed of 0.4 m / min. The parameters of the selected sealing device are as follows: the groove depth of the high-temperature resistant elastic gasket is 6mm and the groove width is 15mm; the thickness of the elastomer sealing material is 10mm.

[0070] Technical Effects and Analysis: Through the aforementioned welding process, localized vacuum laser welding of thick stainless steel plates was achieved. The resulting weld surface morphology of the thick stainless steel plate is as follows: Figure 7 As shown in (a), local vacuum laser welding achieved high-quality welding of steel with no welding defects on the weld surface and a weld reinforcement of 5 mm. Furthermore, the local vacuum laser welding process was relatively stable, with the vacuum level consistently maintained around 10 Pa.

[0071] Comparative Example 1

[0072] A 50mm thick stainless steel plate was selected. Before welding, dust and oil were removed from the plate surface to ensure cleanliness. A localized vacuum composite sealing device was used to adhere to the plate surface, and a vacuum environment was created using a vacuum pump. The composite sealing assembly included a vacuum chamber and an embedded elastomeric sealing material. The high-temperature resistant elastic gasket facing the weld was flat and ungrooved. An elastic thermally conductive layer and the elastomeric sealing material were bonded together using a high-temperature resistant adhesive. Vacuum laser welding experiments were conducted when the vacuum level was maintained at 10Pa. Selected welding parameters: welding power 10 kW, welding speed 0.4 m / min. Selected sealing device parameters: elastomeric sealing material thickness 10mm.

[0073] 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 (b), the local vacuum laser welding technology successfully welded thick stainless steel plates without any welding defects on the weld surface, but the weld reinforcement was only 0.8 mm. Furthermore, the molten pool fluctuated significantly during the local vacuum laser welding process, resulting in severe metal spatter. The vacuum level increased from the initial 10 Pa to 100 Pa, leading to severe oxidation of the weld surface. Simultaneously, the reduced vacuum level generated a large amount of plasma plume during welding, causing contamination of the protective lens and a significant reduction in weld penetration. This was mainly due to the difficulty in fully fitting the flat, high-temperature resistant sealing material to the arc-shaped contour of the weld reinforcement, resulting in gaps and vacuum leakage during the welding process.

[0074] Comparative Example 2

[0075] A 50mm thick stainless steel plate was selected. Before welding, dust and oil were removed from the plate surface to ensure cleanliness. A localized vacuum single-seal device was used to adhere to the plate surface, and a vacuum environment was created using a vacuum pump. The single-material sealing component included a vacuum chamber and a high-temperature resistant elastic gasket conforming to the weld contour. The high-temperature resistant elastic gasket had a groove on the side facing the weld. An elastic thermally conductive layer and an elastomeric sealing material were bonded together using a high-temperature resistant adhesive. Vacuum laser welding experiments were conducted when the vacuum level was maintained at 10Pa. Selected welding parameters: welding power of 10 kW, welding speed of 0.4 m / min. Selected sealing device parameters: groove depth of the high-temperature resistant elastic gasket was 6mm, and groove width was 15mm.

[0076] 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 (c), the weld surface is severely oxidized, and the weld reinforcement is only 0.5 mm. Furthermore, the molten pool fluctuates significantly during the localized vacuum laser welding process, resulting in severe metal spatter, and the vacuum level increases from the initial 10 Pa to 10000 Pa. Simultaneously, due to the decrease in vacuum level, a large amount of plasma plume is generated during welding, severely contaminating the protective lens and significantly reducing the weld penetration. This is mainly because the temperature in the weld area is extremely high during laser welding, often exceeding 1500℃. A single high-temperature resistant elastic gasket is prone to softening, aging, or melting under continuous high-temperature radiation, thus rapidly losing its sealing performance and leading to a significant decrease in vacuum level.

[0077] Comparative Example 3

[0078] A 50mm thick stainless steel plate was selected. Before welding, dust and oil were removed from the plate surface to ensure cleanliness. A localized vacuum composite sealing device was used to adhere to the plate surface, and a vacuum environment was created using a vacuum pump. The composite sealing assembly included a vacuum shroud and a high-temperature resistant elastic gasket conforming to the weld contour. The high-temperature resistant elastic gasket had a groove on the side facing the weld, and an elastomer sealing material was bonded to the outer wall of the groove using a high-temperature resistant adhesive. Vacuum laser welding experiments were conducted when the vacuum level was maintained at 10 Pa. Selected welding parameters: welding power 10 kW, welding speed 0.4 m / min. Selected sealing device parameters: groove depth of the high-temperature resistant elastic gasket 6mm, groove width 15mm; elastomer sealing material thickness 10mm.

[0079] Technical Effects and Analysis: The welding process described resulted in severe surface oxidation of the weld, with a weld reinforcement height of only 0.6 mm. Furthermore, the molten pool fluctuated significantly during the localized vacuum laser welding process, leading to severe metal spatter and an increase in vacuum level from the initial 10 Pa to 1000 Pa. Simultaneously, the reduced vacuum level generated a large amount of plasma plume during welding, severely contaminating the protective lens and drastically reducing the weld penetration. This was primarily due to the lack of an elastic heat-conducting layer during laser welding, resulting in heat accumulation and extremely high temperatures in the weld area. This caused the high-temperature resistant elastic gasket to soften, age, or melt under continuous high-temperature radiation, rapidly losing its sealing performance and leading to a significant reduction in vacuum level.

[0080] Example 2

[0081] A 50mm thick stainless steel plate was selected. Before welding, dust and oil were removed from the plate surface to ensure cleanliness. A localized vacuum composite sealing device was used to adhere to the plate surface, and a vacuum environment was created using a vacuum pump. The composite sealing assembly included a vacuum shroud and a high-temperature resistant elastic gasket shaped like the weld contour embedded within it. The high-temperature resistant elastic gasket had a groove on the side facing the weld, and an elastomeric sealing material was fixed to the outer wall of the groove using a high-temperature resistant adhesive. The elastomeric sealing material contained a hollow cavity for filling with pressurized fluid, which circulated during welding for cooling. Vacuum laser welding experiments were conducted when the vacuum level was maintained at 10Pa. Selected welding parameters: welding power 0.5 kW, welding speed 1 m / min. Selected sealing device parameters: groove depth of the high-temperature resistant elastic gasket 0.1mm, groove width 0.1mm; elastomeric sealing material thickness 2mm.

[0082] 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 a weld reinforcement height of 0.5 mm. Furthermore, the localized vacuum laser welding process was relatively stable, with the vacuum level consistently maintained around 10 Pa.

[0083] Comparative Example 4

[0084] A 50mm thick stainless steel plate was selected. Before welding, dust and oil were removed from the plate surface to ensure cleanliness. A localized vacuum composite sealing device was used to adhere to the plate surface, and a vacuum environment was created using a vacuum pump. The composite sealing assembly included a vacuum shroud and a high-temperature resistant elastic gasket conforming to the weld contour. The high-temperature resistant elastic gasket had a groove on the side facing the weld, and an elastomer sealing material was bonded to the outer wall of the groove using a high-temperature resistant adhesive. Vacuum laser welding was conducted when the vacuum level was maintained at 10 Pa. Selected welding parameters: welding power 0.5 kW, welding speed 1 m / min. Selected sealing device parameters: groove depth of the high-temperature resistant elastic gasket 0.05mm, groove width 0.05mm; elastomer sealing material thickness 2mm.

[0085] Technical effects and analysis: The welding process described above achieved localized vacuum laser welding of thick stainless steel plates. However, due to the mismatch between the groove depth and width, the high-temperature sealing material could not fully conform to the arc-shaped contour of the weld reinforcement, resulting in gaps and vacuum leakage during the welding process. Increasing the vacuum level from the initial 10 Pa to 10000 Pa led to severe oxidation of the weld surface, and the resulting weld reinforcement was only 0.1 mm.

[0086] Example 3

[0087] A 250mm thick stainless steel plate was selected. Before welding, dust and oil were removed from the plate surface to ensure cleanliness. A localized vacuum composite sealing device was used to adhere to the plate surface, and a vacuum environment was created using a vacuum pump. The composite sealing assembly included a vacuum shroud and a high-temperature resistant elastic gasket shaped like the weld contour embedded within it. The high-temperature resistant elastic gasket had a groove on the side facing the weld. An elastomer sealing material was bonded to the outer wall of the groove using a high-temperature resistant adhesive. The elastomer sealing material contained a hollow cavity for filling with pressurized fluid, which circulated during welding for cooling. Vacuum laser welding experiments were conducted when the vacuum level was maintained at 10 Pa. Selected welding parameters: welding power 100 kW, welding speed 0.2 m / min. Selected sealing device parameters: groove depth of the high-temperature resistant elastic gasket 50mm, groove width 100mm; elastomer sealing material thickness 50mm.

[0088] 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 a weld reinforcement height of 20mm. Furthermore, the localized vacuum laser welding process was relatively stable, with the vacuum level consistently maintained around 10Pa.

[0089] Comparative Example 5

[0090] A 250mm thick stainless steel plate was selected. Before welding, dust and oil were removed from the plate surface to ensure cleanliness. A localized vacuum composite sealing device was used to adhere to the plate surface, and a vacuum environment was created using a vacuum pump. The composite sealing assembly included a vacuum shroud and a high-temperature resistant elastic gasket shaped like the weld contour embedded within it. The high-temperature resistant elastic gasket had a groove on the side facing the weld, and an elastomer sealing material was bonded to the outer wall of the groove using a high-temperature resistant adhesive. Vacuum laser welding experiments were conducted when the vacuum level was maintained at 10 Pa. Selected welding parameters: welding power 100 kW, welding speed 0.2 m / min. Selected sealing device parameters: groove depth of the high-temperature resistant elastic gasket 60mm, groove width 150mm; elastomer sealing material thickness 50mm.

[0091] Technical effects and analysis: The welding process described above achieved localized vacuum laser welding of thick stainless steel plates. However, due to the excessive depth and width of the groove, the high-temperature resistant sealing material could not fully conform to the arc-shaped contour of the weld reinforcement, leading to damage to the sealing material and vacuum leakage. Increasing the vacuum level from the initial 10 Pa to 100 Pa resulted in severe oxidation of the weld surface, and the resulting weld reinforcement was only 1.5 mm.

[0092] 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.

[0093] 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 device, characterized by, 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 cover 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 cover 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) includes a strip-shaped elastic body (31) and a high-temperature resistant elastic pad (32) arranged sequentially along the direction close to the workpiece to be welded. A contoured groove (30) is formed on the bottom end face of the strip-shaped elastic body (31). The contoured groove (30) extends through both ends of the strip-shaped elastic body (31) along the length direction of the weld. The high-temperature resistant elastic pad (32) is connected to the groove wall of the contoured groove (30) and can fit against the outer wall of the weld by its own deformation.

2. The local vacuum laser welding device of claim 1, wherein, The strip-shaped elastic body (31) has a hollow cavity (312) recessed toward the side away from the workpiece to be welded. The high-temperature resistant elastic gasket (32) is sealed to the opening of the hollow cavity (312). The hollow cavity (312) is filled with pressurized fluid. An auxiliary positioning groove (13) is formed on the bottom end surface of the vacuum shroud (1) and is fitted with the top end surface of the strip-shaped elastic body (31).

3. The local vacuum laser welding device of claim 2, wherein, 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 device of claim 3, wherein, 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 device of claim 4, wherein, 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); the inlet tube (44) is connected to the filling tube (313) located inside the elastic sealing ring (2).

6. The local vacuum laser welding device of claim 5, wherein, 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 device of claim 3, wherein, An elastic heat-conducting layer (33) is provided between the high-temperature resistant elastic pad (32) and the contoured groove (30); the elastic sealing ring (2) includes an insert ring (21) that is fitted into the assembly ring groove (14) on the bottom end of the vacuum shroud (1), the assembly ring groove (14) is a constricted groove, and the cross-sectional shape of the insert ring (21) matches the cross-sectional shape of the assembly ring groove (14).

8. The local vacuum laser welding device of claim 7, wherein, 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 3, characterized in that, The weld sealing strip assembly (3) has two symmetrical sections about the cover hole (11).

10. A welding method using the local vacuum laser welding apparatus according to any one of claims 3 to 9, characterized by, Includes the following steps: Position the workpiece to be welded after cleaning; Select the weld sealing strip assembly (3) corresponding to the weld reinforcement height of the workpiece to be welded and assemble the weld sealing strip assembly (3) with the vacuum hood (1), and control the operation of the active cooling circulation component so that the pressure fluid in the hollow cavity (312) reaches the preset pressure; The local vacuum laser welding device is started to weld the workpiece to be welded. During the welding process, the real-time pressure in the hollow cavity (312) is detected and the circulating pressure pump (42) is adjusted to ensure that the real-time pressure is maintained at the preset pressure.

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