A heterogeneous material welding method applied to a brush seal structure

Abstract

This invention belongs to the field of heterogeneous material welding, specifically relating to a method for welding heterogeneous materials applied to brush-type sealing structures. First, a backing plate and brush filaments are prepared. After ultrasonic cleaning and drying, the brush filaments are tightly arranged in the backing plate at different ratios. An electron beam is applied using a vacuum electron beam welding device. By filling the backing plate with brush filaments, a brush-type sealing assembly with stable structure and excellent performance is obtained using vacuum electron beam welding technology. This method improves upon existing welding methods for brush-type sealing structures. The weld depth-to-width ratio obtained by this method can reach 4:1, with no defects such as incomplete welding, incomplete penetration, porosity, or undercut. The yield strength at the weld can reach up to 800 MPa, significantly improving post-weld performance.

Description

Technical Field

[0001] This invention belongs to the field of heterogeneous material welding, specifically relating to a heterogeneous material welding method applied to brush seal structures, applicable to the manufacturing of brush seal components for turbine machinery such as aero engines, industrial gas turbines, and steam turbines. Background Technology

[0002] Sealing technology has always been a key technology in the development of high-performance aero engines. By reducing the leakage of airflow inside the engine, it can greatly improve the engine's performance and efficiency. Its characteristics have a significant impact on aero engine performance, especially the air passage seal, which directly affects the improvement of engine pressure ratio and turbine efficiency. As one of the key technologies in the development of modern advanced turbine machinery, brush seals have a leakage rate of 1 / 5 to 1 / 10 that of comb labyrinth seals, and can maintain a constant sealing capacity even under severe transient misalignment between moving and stationary components. This improves both unit efficiency and rotor stability, and has been applied to turbomachinery such as aero engines, industrial gas turbines, and steam turbines.

[0003] The brush seal structure consists of front and rear back plates and brush filaments sandwiched between them, all welded together. However, the brush filaments are prone to detachment and incomplete welds during welding and use, making the weld seam a weak point in the entire seal structure. Traditional electron beam welding involves injecting the brush from the tail of the back plate, requiring a specialized high-precision fixture to tightly arrange and clamp 90-180 wires / mm circumferentially at a preset angle, while simultaneously fixing the front and rear baffles precisely. The relative positions of all three components must be strictly guaranteed, which limits the efficiency of large-scale production to some extent.

[0004] The patent with publication number CN121179018A proposes a femtosecond and picosecond composite laser welding method and equipment for heterogeneous materials. It focuses on welding glass / metal heterogeneous materials, suppressing cracks in transparent materials and improving connection strength. However, it is fundamentally different from the heterogeneous welding requirements of brush-type sealing structures and cannot solve key problems such as brush filament detachment and incomplete welding that lead to sealing failure.

[0005] Patent CN119057241A discloses a titanium-steel dissimilar metal connection and its processing method. For titanium-steel dissimilar metal connection, it relies on a Cu-V composite interlayer to suppress brittle phases and achieves connection through a composite interlayer. However, the brush filaments of brush seals are densely arranged, making it impossible to add an interlayer between each brush filament and the backing plate. It relies on an interlayer of a specific thickness (0.03mm copper foil, 0.05mm vanadium foil) and precise laser parameter control, which is complex and costly, and does not meet the needs of large-scale production of brush seals.

[0006] The patent with publication number CN117697060A proposes a method for joining dissimilar materials, titanium and solder, for sealing vacuum containers. This method achieves dissimilar connection through a multi-step process involving metal transition section, cladding, stamping, and joining. However, it focuses on the indirect connection between titanium and solder, rather than the direct fusion of dissimilar metals between the brush filament and the backplate. This method cannot meet the high-strength metallurgical bonding requirements of the brush filament and the backplate, and the weld strength is insufficient to support the long-term use of the sealing structure.

[0007] The patent with publication number CN112077428A proposes a method for controlling electron beam weld defects in brush-type sealing rings. This method only addresses electron beam welding defects in brush-type sealing rings made of homogeneous materials and does not consider the fusion problems caused by differences in the thermophysical properties of dissimilar materials (such as stainless steel backing plate and cobalt-based alloy brush filaments). Therefore, it cannot solve the risks of incomplete welding and detachment under dissimilar combinations.

[0008] Therefore, it is necessary to explore more operable and reliable welding methods to improve welding quality, and to develop a welding method suitable for the structural characteristics of brush seals and for heterogeneous material combinations, so as to provide support for the high-performance and large-scale application of brush seals. Summary of the Invention

[0009] To address the problems existing in current brush seal structure welding technology, the purpose of this invention is to propose a dissimilar material welding method for brush seal structures. By filling the back plate with brush filaments and using vacuum electron beam welding technology, a brush seal assembly with stable structure and excellent performance is obtained. This method solves the problems of brush filament detachment and incomplete welding, while simplifying the process and improving production efficiency.

[0010] The technical solution of this invention is:

[0011] A method for welding dissimilar materials for use in brush seal structures includes the following steps:

[0012] Step 1: Prepare heterogeneous materials for the back plate and brush bristles. Polish the surfaces of the brush bristles and back plate to a metallic luster. Perform ultrasonic cleaning on the polished brush bristles and back plate in anhydrous ethanol solvent for no less than 20 minutes and then dry them. Cut a groove from one side of the back plate and insert the brush bristles longitudinally and tightly into the groove.

[0013] Step 2: At the starting and ending points of the tightly arranged brush seal structure, the arc-starting plate and the lead-out plate are fixed by argon arc spot welding, respectively. The arc-starting plate and the lead-out plate are made of the same grade as the back plate.

[0014] Step 3: Use a tooling to fix and align the brush seal structure. The tooling has a hollow area along the length of the pad. After aligning the welding area with the hollow area, fix the brush seal on the pad.

[0015] Step 4: Place the brush-type sealing structure reinforced by spot welding in the vacuum chamber of the electron beam welding machine, fix it with a clamp, and perform electron beam welding after evacuation; maintain the vacuum atmosphere for 3 to 5 minutes after welding, and then open the electron beam vacuum chamber to air cool the weldment.

[0016] In the dissimilar material welding method applied to the brush seal structure, in step one, the back plate material is AISI410L ferritic stainless steel, and the brush bristle material is NS163 cobalt-based high-temperature alloy.

[0017] In the dissimilar material welding method applied to the brush-type sealing structure, in step one, the brush-type sealing structure includes brush bristles and a back plate. The back plate is an annular structure with an annular groove on its inner sidewall. The brush bristles are longitudinally and tightly inserted into the groove to achieve initial positioning. The electron beam weld is the contact area between the brush bristles and the back plate, and the electron beam is perpendicular to the electron beam weld.

[0018] In the dissimilar material welding method applied to the brush sealing structure, in step one, an annular groove is cut on the inner sidewall of the back plate at a position 2-3 mm away from the upper surface of the back plate to fill the brush filaments.

[0019] In the dissimilar material welding method applied to the brush-type sealing structure, in step two, the argon gas flow rate for argon arc spot welding is 16L / min, the welding machine current is 95A, and the spot welding positions are the bottom contact ends of the back plate and the arc-starting plate and the arc-ending plate, a total of 3 to 5 points.

[0020] In the dissimilar material welding method applied to the brush-type sealing structure, the process parameters for electron beam welding in step four are: electron beam current 12mA~14.5mA, working distance 490mm, accelerating voltage 110kV, and welding speed 800mm / min.

[0021] In the dissimilar material welding method applied to brush-type sealing structures, in step four, the vacuum pressure in the electron beam welding machine's vacuum chamber is lower than 5 × 10⁻⁶. -4 Pa, electron gun vacuum pressure is below 5 × 10 -5 Pa.

[0022] In the dissimilar material welding method applied to the brush-type sealing structure, in step four, pre-welding adjustment is performed before electron beam welding. The back plate to be welded area is aligned with the electron beam, and the positioning is calibrated to coincide with the beam spot position. The surface focusing current is determined to be 1955mA.

[0023] The design concept of this invention is:

[0024] This invention changes the traditional method of electron beam injection from the tail of the backplate, allowing the electron beam to act directly on the contact area between the brush filaments and the backplate, achieving direct metallurgical bonding of dissimilar materials and fundamentally strengthening the weld's strength. This invention eliminates the need for intermediate layers, cladding, or stamping processes. Ultrasonic cleaning ensures material cleanliness, argon arc spot welding ensures stable arc initiation / exit, and perforated fixtures provide precise positioning, simplifying the overall process. Addressing the thermophysical characteristics of dissimilar materials (differences in melting point and thermal conductivity), this invention optimizes key parameters such as vacuum level, electron beam current, and accelerating voltage to ensure full fusion of the two materials without excessive thermal damage, while preventing brush filament breakage or backplate deformation. Combining the dense arrangement of the brush filaments, this invention designs a grooved insertion arrangement and perforated fixture positioning, ensuring brush filament arrangement accuracy while minimizing fixture interference with the welding process.

[0025] This invention features a perforated area along the length of the backing plate, aligning the welding area with this perforated area. The width of the perforated area can be 2-5 mm larger than the welding area, and its length covers the entire welding path. This reduces the heat conduction interference of the backing plate on the weld and prevents residual stress caused by uneven weld cooling. During electron beam welding, the accelerating voltage is set to 110 kV to accommodate the melting point differences between dissimilar materials (AISI 410L melting point approximately 1480°C, NS163 melting point approximately 1390°C). The electron beam current range of 12 mA to 14.5 mA ensures sufficient fusion of the two materials without excessive thermal damage, preventing brush wire breakage.

[0026] Compared with existing brush-type sealing structure welding methods, the present invention has the following main advantages and beneficial effects:

[0027] 1. Greater Freedom in Product Design: Traditional methods may impose specific constraints on the backplate structure to ensure the electron beam reaches the welding area (e.g., sufficient penetration space and thickness are required at the tail). This invention, by changing the electron beam's direction, allows the electron beam to directly act on the contact area between the backplate and the brush bristles, freeing the backplate from structural design constraints. Engineers can more freely optimize the backplate structure to meet mechanical or fluid performance requirements without being overly constrained by the welding process.

[0028] 2. Improved Welding Quality and Structural Reliability: Traditional methods inject electron beams from the tail of the backplate, making the weld a weak point in the structure, prone to filament detachment and incomplete welds. This invention changes the direction of electron beam injection, directing it to the contact area between the backplate and the filaments. This direct fusion of dissimilar materials fundamentally enhances the weld's strength and reduces the risk of failure.

[0029] 3. Simplified tooling and fixtures, reducing manufacturing difficulty and cost: Traditional methods require the design of specialized high-precision fixtures to strictly fix the relative positions of thousands of brush filaments and the front and rear back plates, which places extremely high demands on fixture accuracy. The new welding path of this invention reduces the stringent requirements for clamping, thereby simplifying or even eliminating complex fixtures, making the manufacturing process simpler and cheaper.

[0030] 4. Improves production efficiency and adapts to large-scale production: The complex clamping and positioning steps in traditional methods limit the production pace. This invention simplifies fixtures and assembly requirements, reduces cumbersome clamping and positioning steps, optimizes the production process, significantly improves assembly and welding efficiency, and makes it easier to automate and scale up production.

[0031] Furthermore, the yield strength at the weld of the brush seal structure obtained using the method of this invention can reach up to 800 MPa. Therefore, this invention not only solves the problem of effective welding of brush seal structures, but also further improves weld quality and production efficiency, demonstrating significant technical advantages. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the brush seal structure designed for this invention.

[0033] Figure 2 This is a schematic diagram of the electron beam welding process.

[0034] Figure 3 The image shows the surface morphology of the electron beam weld seam, obtained by cutting a portion of the backplate.

[0035] Figure 4 A longitudinal section morphology diagram of the electron beam weld seam, showing a portion of the backplate.

[0036] Figure labeling: 1-Brush bristles; 2-Back plate; 3-Electron beam weld; 4-Electron beam. Detailed Implementation

[0037] like Figures 1-2 As shown, the brush seal structure includes brush bristles 1 and a back plate 2. The back plate 2 is an annular structure with an annular groove on its inner sidewall. The brush bristles 1 are longitudinally and tightly inserted into the groove for initial positioning. The electron beam weld seam 3 is the contact area between the brush bristles 1 and the back plate 2, and the electron beam 4 is perpendicularly pointed to the electron beam weld seam 3 (i.e., the contact interface between the brush bristles 1 and the back plate 2). First, the back plate and brush bristles are prepared. After ultrasonic cleaning and drying, the brush bristles are arranged tightly in the back plate in different proportions. An electron beam is applied using a vacuum electron beam welding device. The above method improves the welding method of the existing brush seal structure.

[0038] To make the technical problems, technical solutions, and advantages of this invention clearer, a detailed description will be provided below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the descriptions of these embodiments are intended to aid in understanding the invention but do not constitute a limitation thereof. Unless otherwise specified, the experimental and detection methods described in the following embodiments are conventional methods; the reagents and materials described are commercially available unless otherwise specified.

[0039] The equipment used in this invention is an EB4C-150-15-W electron beam welder with a power of 15KW, an accelerating voltage between 100kV and 160kV, a beam current between 0 and 100mA, and a welding vacuum pressure below 10 kWh. -3 Pa.

[0040] The brush sealing structure and electron beam welding process provided by this invention are as follows: Figure 1 , Figure 2 As shown. Brush 1 is made of NS163 cobalt-based high-temperature alloy with a diameter of 0.5 mm, and back plate 2 is an annular AISI 410L ferritic stainless steel plate with an outer diameter of 50 mm, a ring width of 20 mm, and a thickness of 8 mm. An annular groove with an outer diameter of 40 mm, a ring width of 15 mm, and a thickness of 1 mm to 4 mm is opened on the inner side of back plate 2. Both workpieces are in the rolled annealed state. The chemical composition is shown in Table 1.

[0041] Table 1. Chemical composition (mass percentage) of AISI 410L and NS163

[0042] Brand C Fe Cr Ni Ti Nb Si Al Co V Mn AISI 410L 0.015 Bal. 12.00 0.10 - - 0.60 - - 0.10 0.20 NS163 0.094 21.60 26.92 8.02 0.96 1.04 0.16 0.35 Bal. - -

[0043] Example 1

[0044] In this embodiment, a method for welding dissimilar materials applied to a brush seal structure includes the following steps:

[0045] The first step involves preparing an annular AISI 410L ferritic stainless steel plate with an outer diameter of 50mm, a ring width of 20mm, and a thickness of 8mm; NS163 cobalt-based high-temperature alloy with a diameter of 0.5mm; an arc-starting plate; an arc-ending plate; 99wt% anhydrous ethanol; scouring pads; 3009 type microfiber lint-free cloth; feeler gauges, and other measuring tools. At a position 2mm from the top surface of the AISI 410L ferritic stainless steel plate, a ring groove with an outer diameter of 40mm, a ring width of 15mm, and a thickness of 4mm is cut from the inner wall of the AISI 410L ferritic stainless steel plate using a wire EDM machine to fill the groove with NS163 brush filaments. To enhance the surface bonding of the weldment, promote metal-to-metal fusion during welding, and prevent inclusions within the weld, the oxide scale on the surface of the plate and inside the groove must be removed with a scraper. Then, a fine-mesh lint-free cloth dampened with alcohol should be used to wipe away oil and foreign impurities from the back plate and brush bristles to be welded. Simultaneously, the surfaces of the arc-starting and arc-ending plates should be cleaned. Protective gloves must be worn throughout the surface cleaning process. Subsequently, all polished materials should be ultrasonically cleaned for 30 minutes in anhydrous ethanol solution, and then the surface moisture should be dried using compressed air.

[0046] The second step, as Figures 1-2 As shown, NS163 cobalt-based high-temperature alloy brush wires were inserted into the grooves of the back plate, ensuring a tight arrangement. The arc-starting and arc-ending plates were then reinforced with argon arc welding before and after the arranged structure. The material of the argon wires was the same as that of the back plate. The argon flow rate was 16 L / min, the welding current was 95 A, and four spot welds were performed at the bottom contact points between the AISI 410L back plate and the arc-starting and arc-ending plates. After spot welding, the welds were wiped with alcohol, and the welds were inspected for cracks and a silver-white color.

[0047] The third step is to fix the entire workpiece in a bench vise, move the vise to ensure that the distance between the AISI 410L surface to be welded and the gun chamber is 490mm. Then place it in the vacuum chamber of the electron beam welding machine, evacuate the vacuum chamber, and set the vacuum chamber pressure to 3×10⁻⁶. -4 Pa, the vacuum pressure of the electron gun is 3 × 10⁻⁶ Pa. -5 At Pa, pre-welding adjustments are initiated. The area to be soldered on the backplate is aligned under the electron beam, and the positioning is calibrated to coincide with the beam spot position. Under the predetermined working distance of 490mm, the surface focusing current is determined to be 1955mA.

[0048] The fourth step uses the following welding parameters: electron beam current of 14.5 mA, accelerating voltage of 110 kV, and welding speed of 800 mm / min. After welding, the vacuum atmosphere is maintained for 3-5 minutes, then the electron beam vacuum chamber is opened to allow the workpiece to air cool. The workpiece is then removed, and its surface is wiped with alcohol. The surface and longitudinal section morphology of the weld are as follows. Figure 3 , Figure 4As shown, visual inspection revealed that the weld formation was good, with no defects such as incomplete welding, lack of penetration, porosity, or undercut. The weld depth-to-width ratio was 4:1. Strength testing determined the weld yield strength to be 390 MPa.

[0049] Example 2

[0050] In this embodiment, a method for welding dissimilar materials applied to a brush seal structure includes the following steps:

[0051] The first step involves preparing an annular AISI 410L ferritic stainless steel plate with an outer diameter of 50mm, a ring width of 20mm, and a thickness of 8mm; NS163 cobalt-based high-temperature alloy with a diameter of 0.5mm; an arc-starting plate; an arc-ending plate; 99wt% anhydrous ethanol; scouring pads; 3009 type microfiber lint-free cloth; feeler gauges, and other measuring tools. At a position 2mm from the top surface of the AISI 410L ferritic stainless steel plate, a ring groove with an outer diameter of 40mm, a ring width of 15mm, and a thickness of 1mm is cut from the inner wall of the AISI 410L ferritic stainless steel plate using a wire EDM machine to fill the groove with NS163 brush filaments. To enhance the surface bonding of the weldment, promote metal-to-metal fusion during welding, and prevent inclusions within the weld, the oxide scale on the surface of the plate and inside the groove must be removed with a scraper. Then, a fine-mesh lint-free cloth dampened with alcohol should be used to wipe away oil and foreign impurities from the back plate and brush bristles to be welded. Simultaneously, the surfaces of the arc-starting and arc-ending plates should be cleaned. Protective gloves must be worn throughout the surface cleaning process. Subsequently, all polished materials should be ultrasonically cleaned for 30 minutes in anhydrous ethanol solution, and then the surface moisture should be dried using compressed air.

[0052] The second step, as Figures 1-2 As shown, NS163 cobalt-based high-temperature alloy brush wires were inserted into the grooves of the back plate, ensuring a tight arrangement. The arc-starting and arc-ending plates were then reinforced with argon arc welding before and after the arranged structure. The material of the argon wires was the same as that of the back plate. The argon flow rate was 16 L / min, the welding current was 95 A, and four spot welds were performed at the bottom contact points between the AISI 410L back plate and the arc-starting and arc-ending plates. After spot welding, the welds were wiped with alcohol, and the welds were inspected for cracks and a silver-white color.

[0053] The third step is to fix the entire workpiece in a bench vise, move the vise to ensure that the distance between the AISI 410L surface to be welded and the gun chamber is 490mm. Then place it in the vacuum chamber of the electron beam welding machine, evacuate the vacuum chamber, and set the vacuum chamber pressure to 1×10⁻⁶. -4 Pa, the vacuum pressure of the electron gun is 1×10⁻⁶ Pa. -5 At Pa, pre-welding adjustments are initiated. The area to be soldered on the backplate is aligned under the electron beam, and the positioning is calibrated to coincide with the beam spot position. Under the predetermined working distance of 490mm, the surface focusing current is determined to be 1955mA.

[0054] The fourth step involved welding with an electron beam current of 14.5 mA, an accelerating voltage of 110 kV, and a welding speed of 800 mm / min. After welding, the vacuum atmosphere was maintained for 3-5 minutes, and then the electron beam vacuum chamber was opened to allow the workpiece to air cool. The workpiece was then removed and its surface was wiped with alcohol. Visual inspection revealed a good weld formation, with no defects such as incomplete welds, lack of penetration, porosity, or undercut. Strength testing showed a weld yield strength of 790 MPa.

[0055] Example 3

[0056] In this embodiment, a method for welding dissimilar materials applied to a brush seal structure includes the following steps:

[0057] The first step involves preparing an annular AISI 410L ferritic stainless steel plate with an outer diameter of 50mm, a ring width of 20mm, and a thickness of 8mm; NS163 cobalt-based high-temperature alloy with a diameter of 0.5mm; an arc-starting plate; an arc-ending plate; 99wt% anhydrous ethanol; a scouring pad; a 3009 type microfiber lint-free cloth; a feeler gauge, and other measuring tools. At a position 2mm from the top surface of the AISI 410L ferritic stainless steel plate, a ring groove with an outer diameter of 40mm, a ring width of 15mm, and a thickness of 2mm is cut from the inner wall of the AISI 410L ferritic stainless steel plate using a wire EDM machine to fill the groove with NS163 brush filaments. To enhance the surface bonding of the weldment, promote metal-to-metal fusion during welding, and prevent inclusions within the weld, the oxide scale on the surface of the plate and inside the groove must be removed with a scraper. Then, a fine-mesh lint-free cloth dampened with alcohol should be used to wipe away oil and foreign impurities from the back plate and brush bristles to be welded. Simultaneously, the surfaces of the arc-starting and arc-ending plates should be cleaned. Protective gloves must be worn throughout the surface cleaning process. Subsequently, all polished materials should be ultrasonically cleaned for 30 minutes in anhydrous ethanol solution, and then the surface moisture should be dried using compressed air.

[0058] The second step, as Figures 1-2 As shown, NS163 cobalt-based high-temperature alloy brush wires were inserted into the grooves of the back plate, ensuring a tight arrangement. The arc-starting and arc-ending plates were then reinforced with argon arc welding before and after the arranged structure. The material of the argon wires was the same as that of the back plate. The argon flow rate was 16 L / min, the welding current was 95 A, and four spot welds were performed at the bottom contact points between the AISI 410L back plate and the arc-starting and arc-ending plates. After spot welding, the welds were wiped with alcohol, and the welds were inspected for cracks and a silver-white color.

[0059] The third step is to fix the entire workpiece in a bench vise, move the vise to ensure that the distance between the AISI 410L surface to be welded and the gun chamber is 490mm. Then place it in the vacuum chamber of the electron beam welding machine, evacuate the vacuum chamber, and set the vacuum chamber pressure to 2×10⁻⁶. -4 Pa, the vacuum pressure of the electron gun is 2 × 10⁻⁶ Pa. -5At Pa, pre-welding adjustments are initiated. The area to be soldered on the backplate is aligned under the electron beam, and the positioning is calibrated to coincide with the beam spot position. Under the predetermined working distance of 490mm, the surface focusing current is determined to be 1955mA.

[0060] The fourth step involved welding with an electron beam current of 12mA, an accelerating voltage of 110kV, and a welding speed of 800mm / min. After welding, the vacuum atmosphere was maintained for 3-5 minutes, and then the electron beam vacuum chamber was opened to allow the workpiece to air cool. The workpiece was then removed and its surface was wiped with alcohol. Visual inspection revealed a good weld formation, with no defects such as incomplete welds, lack of penetration, porosity, or undercut. Strength testing showed a weld yield strength of 400MPa.

[0061] The comparative analysis of the above embodiments shows that, in the process of welding the brush seal structure using electron beam welding, both the welding parameters (electron beam current) and the preparation parameters (brush wire ratio) affect the welding quality. Only when these factors are coordinated can the final welding quality meet the requirements. In particular, for the dissimilar combination of AISI410L ferritic stainless steel and NS163 cobalt-based high-temperature alloy commonly used in brush seals, stable metallurgical bonding of the two materials is achieved through the design of special process parameters and steps, avoiding the fusion problems that are prone to occur when welding dissimilar materials.

[0062] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A heterogeneous material welding method applied to a brush seal structure, characterized by, Includes the following steps: Step 1: Prepare heterogeneous materials for the back plate and brush bristles. Polish the surfaces of the brush bristles and back plate to a metallic luster. Perform ultrasonic cleaning on the polished brush bristles and back plate in anhydrous ethanol solvent for no less than 20 minutes and then dry them. Cut an annular groove from one side of the back plate and insert the brush bristles longitudinally and tightly into the annular groove. In step one, the brush sealing structure includes brush bristles and a back plate. The back plate has an annular structure with an annular groove on its inner sidewall. The brush bristles are inserted tightly into the annular groove longitudinally to achieve initial positioning. The electron beam weld is the contact area between the brush bristles and the back plate, and the electron beam is perpendicular to the electron beam weld. Step 2: At the starting and ending points of the tightly arranged brush seal structure, the arc-starting plate and the lead-out plate are fixed by argon arc spot welding, respectively. The arc-starting plate and the lead-out plate are made of the same grade as the back plate. Step 3: Use a tooling to fix and align the brush seal structure. The tooling has a hollow area along the length of the pad. After aligning the welding area with the hollow area, fix the brush seal on the pad. Step 4: Place the brush-type sealing structure reinforced by spot welding in the vacuum chamber of the electron beam welding machine, fix it with a clamp, and perform electron beam welding after evacuation; maintain the vacuum atmosphere for 3 to 5 minutes after welding, and then open the electron beam vacuum chamber to air cool the weldment.

2. The dissimilar material welding method applied to brush seal structures according to claim 1, characterized in that, In step one, the backplate material is AISI410L ferritic stainless steel, and the brush bristle material is NS163 cobalt-based high-temperature alloy.

3. The dissimilar material welding method applied to brush seal structures according to claim 1, characterized in that, In step one, at a distance of 2-3 mm from the upper surface of the back plate, an annular groove is cut on the inner side wall of the back plate using a wire cutting machine to fill the brush filaments.

4. The dissimilar material welding method applied to brush seal structures according to claim 1, characterized in that, In step two, the argon flow rate for argon arc spot welding is 16L / min, the welding machine current is 95A, and the spot welding positions are the bottom contact ends of the back plate and the arc initiation plate and arc termination plate, a total of 3 to 5 points.

5. The dissimilar material welding method applied to a brush seal structure according to claim 1, characterized in that, In step four, the process parameters for electron beam welding are: electron beam current 12mA~14.5mA, working distance 490mm, accelerating voltage 110kV, and welding speed 800mm / min.

6. The dissimilar material welding method applied to a brush seal structure according to claim 5, characterized in that, In step four, the vacuum chamber of the electron beam welder is at a vacuum pressure of less than 5 x 10 -4 Pa, and the electron gun is at a vacuum pressure of less than 5 x 10 -5 Pa.

7. The dissimilar material welding method applied to a brush seal structure according to claim 6, characterized in that, In step four, pre-welding adjustments are performed before electron beam welding. The area to be welded on the backplate is aligned with the electron beam, and the positioning is calibrated to coincide with the beam spot position. The surface focusing current is determined to be 1955mA.

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