A diffusion welding method for layered plate structure cylinder

Abstract

This invention provides a diffusion welding method for layered plate structure cylinders, comprising the following steps: single-piece preparation; outer bushing preparation; cleaning; application of anti-weld flux; assembly; evacuation and sealing; diffusion welding; and machining. Addressing the problems of large temperature differences between the solid frame and adjacent areas, high thermal stress, and material instability that exist when manufacturing layered plate structure components using existing processes, this diffusion welding method for layered plate structure cylinders eliminates the need to retain the solid frame at the weld joint when first welding the layered plate blanks and then welding the cylinder. This achieves direct diffusion welding manufacturing of layered plate structure cylinders without a weld joint frame, improving the uniformity of the circumferential air intake-turbulence-impact structure of the layered plate structure cylinder, improving the cooling effect of the layered plate structure cylinder, and extending the service life of the layered plate structure components. In the layered plate structure cylinders prepared by this invention, the proportion of plate-microstructure welds to the total number is greater than 98%, the weld rate of a single plate-microstructure is greater than 95%, and the deformation before and after welding is less than 0.05 mm.

Description

Technical Field

[0001] This invention relates to the field of aero-engine combustion component manufacturing, and in particular to a diffusion welding method for a layered structure cylinder. Background Technology

[0002] Laminate cooling is a novel composite cooling method that has many advantages, such as reducing the temperature gradient of the component wall, reducing structural thermal stress, saving cooling air consumption, and reducing structural weight. It can effectively improve the structural strength and service life of hot-end components and has significant application advantages in hot-end components such as combustion chamber flame tubes, tail nozzles, and stabilizers. Figure 1 It is a typical structural layered plate.

[0003] The layered flame tube is a typical complex structural component with internal topology optimization features, thin walls, and weak rigidity. Currently, the general process flow for layered flame tube structures is as follows: layered plate single-piece preparation → layered plate blank welding → layered plate blank forming → cutting → splicing and welding → straightening. On high-temperature alloy thin plates, arrayed microstructures and arrayed holes are prepared using precision machining, electrical discharge machining, laser machining, electrolysis, photochemical machining, and LIGA microstructure processing methods to form layered plate single-pieces. Subsequently, diffusion welding and pressure brazing are used to weld and form layered plate structure flat blanks. Then, cold pressing and hot creep forming are used to shape the flat blanks into layered plate structure formed parts with specific curved surfaces. Next, laser cutting or wire cutting is used to remove excess parts, forming a sandwich structure with solid borders on all sides and arrayed microstructures and arrayed holes inside. Next, vacuum electron beam welding, laser welding, or special fusion welding are used to weld several layered plate structure formed parts to form a layered plate structure cylinder. As needed, the layered plate structure cylinder is spliced ​​with the mounting edge or other solid cylinders to form a flame tube. Finally, the layered plate structure flame tube is straightened to improve the dimensional accuracy of the flame tube.

[0004] When assembling layered structural components into a cylindrical body, vacuum electron beam welding, laser welding, or special fusion welding methods must be used. Welding is performed at the solid edges of adjacent layered structural components, and multiple components are welded sequentially to form the layered structural cylindrical body. To ensure the structural strength of the components, holes cannot be machined at the solid edges, nor can microstructures be added laterally. Figure 2 , 3 As shown. There are no cooling holes at the solid frame; cooling relies on nearby array holes and array microstructures. During use, the solid frame experiences high temperatures, leading to the following problems:

[0005] (1) The temperature at the solid frame will be higher than other locations, resulting in greater thermal stress due to the temperature difference;

[0006] (2) The high temperature of the solid frame and the combined effect of the large thermal stress in the adjacent position make the material prone to instability and deformation under the action of high temperature and thermal stress, which may lead to the scrapping of parts.

[0007] The presence of solid borders affects the cooling effect of the shelf structure, becomes a safety hazard during the use of the shelf structure, and limits the application range of the shelf structure. Summary of the Invention

[0008] The purpose of this invention is to address the problems that arise when manufacturing layered structure components using existing processes, it is necessary to retain solid frame edges for welding, and the weld joints cannot be machined with holes or arranged microstructures. These problems include large temperature differences between the solid frame edges and adjacent locations, high thermal stress, and easy material instability. This invention proposes a diffusion welding method for layered structure cylinders, which eliminates the need to retain solid frame edges at the weld joints when welding the layered blanks first and then welding the cylinder. This enables direct diffusion welding manufacturing of layered structure cylinders without weld joint frames, and improves the cooling effect of layered structure cylinders.

[0009] This invention provides a diffusion welding method for a layered structure cylinder, comprising the following steps: single-piece preparation; outer bushing preparation; cleaning; application of anti-weld flux; assembly; evacuation and sealing; diffusion welding; and machining.

[0010] Step 1: Single item preparation

[0011] Prepare the single-piece layer 1 (1), single-piece layer 2 (2), and inner lining cylinder to be welded, wherein:

[0012] (1) Single piece of layer plate (1) is a high temperature alloy cone cylinder with a height of H1, a wall thickness of δ1, an outer diameter of ФA1 at the large end, and an outer diameter of ФB1 at the small end. The cone cylinder wall is machined with an array of holes, such as Figure 4 As shown;

[0013] (2) Single piece of layer plate two (2) is a high temperature alloy cone cylinder with a height of H2 and H2=H1, a wall thickness of δ2, an outer diameter of ФA2 at the large end and an outer diameter of ФB2 at the small end, and ФA2-2×δ2=ФA1, ФB2-2×δ2=ФB1. The cone cylinder wall is machined with array holes, and the inner surface is arranged with array microstructures, such as Figure 5 As shown;

[0014] (3) The inner lining cylinder is a high-temperature alloy cone cylinder with the same material as the single piece of the layer plate (2). The cone cylinder height is H3, and H3=H1, the wall thickness is δ3, the outer diameter of the large end is ФA3, the outer diameter of the small end is ФB3, and ФA1-2×δ1=ФA3, ФB1-2×δ1=ФB3;

[0015] Step 2: Preparation of the outer liner

[0016] Prepare an outer bushing. The bushing material is a high-temperature resistant alloy with a coefficient of linear expansion close to that of the base material being welded. Two rows of vent holes are evenly distributed along the height direction of the inner conical surface of the bushing, with eight vent holes evenly distributed circumferentially in each row. The vent holes are small on the inner conical surface side of the bushing, with a size of approximately Ф1.0 mm, and large on the outer wall side of the bushing, with a size of Ф6.0 mm. The small and large vent holes are concentric. A stainless steel gas pipe is welded to the inlet side of the large vent hole. The gas pipe has an outer diameter of Ф8.0 mm and an inner diameter of Ф6.0 mm; the length of the gas pipe is not limited. An alumina diffusion layer with a thickness of approximately 0.03 mm to 0.05 mm is applied to the inner conical surface of the bushing. Figure 6 As shown.

[0017] Step 3: Cleaning

[0018] Pre-treat the surfaces to be welded of single-piece layer 1 (1) and single-piece layer 2 (2) to remove residual oxides, foreign matter, etc.; clean single-piece layer 1 (1), single-piece layer 2 (2) and inner liner cylinder with deionized water; clean the outer liner with clean water.

[0019] Step 4: Apply solder resist

[0020] Apply a weld-stopping agent evenly to the outer wall surface of the inner liner cylinder and allow it to air dry.

[0021] Step 5: Assembly

[0022] Place the second (2) and first (1) layer plates and the inner liner cylinder sequentially into the outer liner, aligning their end faces; then weld the large and small end faces using a special fusion welding technique. Figure 7 As shown.

[0023] Step Six: Evacuate and Seal

[0024] Connect the vacuum pump to the gas pipe and start the vacuum pump to evacuate the gas, lowering the pressure to below 4 × 10⁻² Pa. Continue evacuating, and then use resistance welding to weld the gas pipes, ensuring at least two resistance welds on each pipe, with each weld being at least 3 mm wide and the center-to-center distance between adjacent welds at least 15 mm. Remove the vacuum pump, and then use argon arc welding to seal the gas pipe joints. Figure 8 As shown.

[0025] Step 7: Diffusion Welding

[0026] After the sealing welding is completed, layer plate 1 and layer plate 2 are sent into a gas pressurization equipment for gas pressurized diffusion welding. The process parameters are as follows:

[0027] Phase 1: Insulation temperature 900℃~1000℃, gas pressure 60MPa~80MPa, insulation time 3h~5h;

[0028] Phase 2: Insulation temperature 1120℃~1200℃, gas pressure 5MPa~25MPa, insulation time 1.5h~4h.

[0029] Step 8: Machining

[0030] First, the weld seams on the large and small ends of the weldment are removed by machining. Then, machining continues along the inner conical surface of the outer bushing, with a radial removal of δ1+δ2+δ3-0.05mm and an axial removal of 2mm-4mm. Finally, mechanical grinding is used to remove the remaining 0.05mm thin layer, allowing the weldment, inner liner, and outer bushing to separate. Figure 9 As shown, the proportion of welded plates and microstructures in the resulting layered structure cylinder is greater than 98% of the total number, the welding rate of a single plate and microstructure is greater than 95%, and the deformation of the layered structure before and after welding is no greater than 0.05 mm.

[0031] Advantages of this invention:

[0032] This invention proposes a diffusion welding method for layered plate structure cylinders. It eliminates the need for a solid frame at the weld joint, which must be retained when welding the layered plate blanks first and then the cylinder body. This enables direct diffusion welding of layered plate structure cylinders without a weld joint frame, improving the uniformity of the circumferential air intake-turbulence-impact structure, enhancing the cooling effect, and extending the service life of the layered plate structure components. The layered plate structure cylinders prepared by this invention have a plate-microstructure weld ratio greater than 98% of the total number of plates, a weld ratio of over 95% for individual plates-microstructures, and a deformation of less than 0.05 mm before and after welding. Attached Figure Description

[0033] Figure 1 A typical schematic diagram of a layered structure;

[0034] Figure 2 Schematic diagram of the welding positions of the formed components of the layered structure;

[0035] Figure 3 Schematic diagram of the welded cross-section of the laminated structure components;

[0036] Figure 4 Schematic diagram of a single shelf unit;

[0037] Figure 5 Schematic diagram of a single shelf piece;

[0038] Figure 6 Schematic diagram of the outer bushing structure;

[0039] Figure 7 Schematic diagram of the assembled result;

[0040] Figure 8 Schematic diagram of the effect after encapsulation;

[0041] Figure 9 Post-welding processing diagram;

[0042] Figure reference numerals: 1-Layer plate single piece one, 2-Layer plate single piece two, 3-Array microstructure, 4-Diffusion weld, 5-Array hole, 6-Welding position, 7-Welding joint, 8-Small vent hole, 9-Large vent hole, 10-Gas pipe, 11-Fillet weld, 12-Edge sealing weld, 13-Resistance weld, 14-End sealing weld. Detailed Implementation

[0043] The present invention will be further explained below with reference to specific implementation schemes, but it is not limited to the present invention. The structures, proportions, sizes, etc. shown in the accompanying drawings are only used to complement the content disclosed in the specification, so as to enable those skilled in the art to understand and read, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size, without affecting the effect and purpose that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0044] Example 1

[0045] Step 1: Single item preparation

[0046] Prepare the single-piece layer 1 (1), single-piece layer 2 (2), and inner lining cylinder to be welded, among which

[0047] (1) The single piece of the layer plate (1) is a GH5188 alloy cone cylinder with a height of 120.0 mm, a wall thickness of 1.4 mm, an outer diameter of 608.0 mm at the large end, and an outer diameter of 592.0 mm at the small end. The cone cylinder wall is machined with an array of holes, such as Figure 4 As shown;

[0048] (2) Single piece of layer plate two (2) is a GH5188 alloy cone cylinder with a height of 120.0 mm, a wall thickness of 1.2 mm, an outer diameter of 610.4 mm at the large end, and an outer diameter of 594.4 mm at the small end. The cone cylinder wall is machined with array holes, and the inner surface is arranged with array microstructures, such as Figure 5 As shown;

[0049] (3) The inner lining cylinder is a GH5188 alloy cone cylinder with a height of 120.0 mm, a wall thickness of 1.5 mm, an outer diameter of 605.2 mm at the large end, and an outer diameter of 589.2 mm at the small end;

[0050] Step 2: Preparation of the outer liner

[0051] Prepare an outer bushing. The bushing material is a high-temperature resistant alloy with a coefficient of linear expansion close to that of the base material being welded. Two rows of vent holes are evenly distributed along the height direction of the inner conical surface of the bushing, with eight vent holes evenly distributed circumferentially in each row. The vent holes are small on the inner conical surface side of the bushing, with a size of approximately Ф1.0 mm, and large on the outer wall side of the bushing, with a size of Ф6.0 mm. The small and large vent holes are concentric. A stainless steel gas pipe is welded to the inlet side of the large vent hole. The gas pipe has an outer diameter of Ф8.0 mm and an inner diameter of Ф6.0 mm; the length of the gas pipe is not limited. An alumina diffusion layer with a thickness of approximately 0.03 mm is applied to the inner conical surface of the bushing. Figure 6 As shown.

[0052] Step 3: Cleaning

[0053] Pre-treat the surfaces to be welded of single-piece layer 1 (1) and single-piece layer 2 (2) to remove residual oxides, foreign matter, etc.; clean single-piece layer 1 (1), single-piece layer 2 (2) and inner liner cylinder with deionized water; clean the outer liner with clean water.

[0054] Step 4: Apply solder resist

[0055] Apply a weld-stopping agent evenly to the outer wall surface of the inner liner cylinder and allow it to air dry.

[0056] Step 5: Assembly

[0057] Place the second (2) and first (1) layer plates and the inner liner cylinder sequentially into the outer liner, aligning their end faces; then weld the large and small end faces using a special fusion welding technique. Figure 7 As shown.

[0058] Step Six: Evacuate and Seal

[0059] Connect the vacuum pump to the gas pipe and start the vacuum pump to evacuate the gas, lowering the pressure to below 4 × 10⁻² Pa. Continue evacuating, and then use resistance welding to weld the gas pipes, with at least two resistance welds on each pipe, each weld being 3 mm wide and approximately 15 mm apart. Remove the vacuum pump, and then use argon arc welding to seal the gas pipe joints. Figure 8 As shown.

[0060] Step 7: Diffusion Welding

[0061] After the sealing welding is completed, layer plate 1 and layer plate 2 are sent into a gas pressurization equipment for gas pressurized diffusion welding. The process parameters are as follows:

[0062] Phase 1: Insulation temperature 900℃, gas pressure 60MPa, insulation time 5h;

[0063] Phase 2: Insulation temperature 1120℃, gas pressure 5MPa, insulation time 4h.

[0064] Step 8: Machining

[0065] First, the weld seams on the large and small ends of the weldment are removed by machining. Then, machining continues along the inner conical surface of the outer bushing, with a radial removal of 4.05 mm and an axial removal of 2 mm. Finally, a thin layer of 0.05 mm is removed by mechanical grinding, allowing the weldment, inner liner, and outer bushing to separate. Figure 9 As shown, the number of welded plates and microstructures in the resulting layered structure cylinder accounts for approximately 98.5% of the total number, the welding rate of a single plate and microstructure is approximately 95.6%, and the deformation of the layered structure before and after welding is 0.04 mm.

[0066] Example 2

[0067] Steps one through six are the same as in Example 1; the other processes follow these steps:

[0068] Step 7: Diffusion Welding

[0069] After the sealing welding is completed, layer plate 1 and layer plate 2 are sent into a gas pressurization equipment for gas pressurized diffusion welding. The process parameters are as follows:

[0070] Phase 1: Insulation temperature 1000℃, gas pressure 80MPa, insulation time 3h;

[0071] Phase 2: Insulation temperature 1200℃, gas pressure 25MPa, insulation time 1.5h.

[0072] Step 8: Machining

[0073] First, the weld seams on the large and small ends of the weldment are removed by machining. Then, machining continues along the inner conical surface of the outer bushing, with a radial removal of 4.05 mm and an axial removal of 2 mm. Finally, a thin layer of 0.05 mm is removed by mechanical grinding, allowing the weldment, inner liner, and outer bushing to separate. Figure 9 As shown, the number of welded plates and microstructures in the resulting layered structure cylinder accounts for approximately 99.2% of the total number, the welding rate of a single plate and microstructure is approximately 98.8%, and the deformation of the layered structure before and after welding is 0.05 mm.

[0074] Example 3

[0075] Steps one through six are the same as in Example 1; the other processes follow these steps:

[0076] Step 7: Diffusion Welding

[0077] After the sealing welding is completed, layer plate 1 and layer plate 2 are sent into a gas pressurization equipment for gas pressurized diffusion welding. The process parameters are as follows:

[0078] Phase 1: Insulation temperature 900℃, gas pressure 80MPa, insulation time 4h;

[0079] Phase 2: Insulation temperature 1120℃, gas pressure 25MPa, insulation time 3h.

[0080] Step 8: Machining

[0081] First, the weld seams on the large and small ends of the weldment are removed by machining. Then, machining continues along the inner conical surface of the outer bushing, with a radial removal of 4.05 mm and an axial removal of 2 mm. Finally, a thin layer of 0.05 mm is removed by mechanical grinding, allowing the weldment, inner liner, and outer bushing to separate. Figure 9 As shown, the number of welded plates and microstructures in the resulting layered structure cylinder accounts for approximately 98.5% of the total number, the welding rate of a single plate and microstructure is approximately 98.7%, and the deformation of the layered structure before and after welding is 0.05 mm.

[0082] Example 4

[0083] Step 1: Single item preparation

[0084] Prepare the single-piece layer 1 (1), single-piece layer 2 (2), and inner lining cylinder to be welded, among which

[0085] (1) The single piece of the layer plate (1) is a GH3230 alloy cone cylinder with a height of 85.0 mm, a wall thickness of 1.0 mm, an outer diameter of 568.0 mm at the large end, and an outer diameter of 542.0 mm at the small end. The cone cylinder wall is machined with an array of holes, such as Figure 4 As shown;

[0086] (2) Single piece of layer plate two (2) is a GH3230 alloy cone cylinder with a height of 85.0 mm, a wall thickness of 1.5 mm, an outer diameter of 571.0 mm at the large end, and an outer diameter of 545.0 mm at the small end. The cone cylinder wall is machined with array holes, and the inner surface is arranged with array microstructures, such as Figure 5 As shown;

[0087] (3) The inner lining cylinder is a GH3230 alloy cone cylinder with a height of 85.0 mm, a wall thickness of δ1.2 mm, an outer diameter of 566.0 mm at the large end, and an outer diameter of 540.0 mm at the small end;

[0088] Step 2: Preparation of the outer liner

[0089] Prepare an outer bushing. The bushing material is a high-temperature resistant alloy with a coefficient of linear expansion close to that of the base material being welded. Two rows of vent holes are evenly distributed along the height direction of the inner conical surface of the bushing, with eight vent holes evenly distributed circumferentially in each row. The vent holes are small on the inner conical surface side of the bushing, with a size of approximately Ф1.0 mm, and large on the outer wall side of the bushing, with a size of Ф6.0 mm. The small and large vent holes are concentric. A stainless steel gas pipe is welded to the inlet side of the large vent hole. The gas pipe has an outer diameter of Ф8.0 mm and an inner diameter of Ф6.0 mm; the length of the gas pipe is not limited. An alumina diffusion layer with a thickness of approximately 0.05 mm is applied to the inner conical surface of the bushing. Figure 6 As shown.

[0090] Step 3: Cleaning

[0091] Pre-treat the surfaces to be welded of single-piece layer 1 (1) and single-piece layer 2 (2) to remove residual oxides, foreign matter, etc.; clean single-piece layer 1 (1), single-piece layer 2 (2) and inner liner cylinder with deionized water; clean the outer liner with clean water.

[0092] Step 4: Apply solder resist

[0093] Apply a weld-stopping agent evenly to the outer wall surface of the inner liner cylinder and allow it to air dry.

[0094] Step 5: Assembly

[0095] Place the second (2) and first (1) layer plates and the inner liner cylinder sequentially into the outer liner, aligning their end faces; then weld the large and small end faces using a special fusion welding technique. Figure 7 As shown.

[0096] Step Six: Evacuate and Seal

[0097] Connect the vacuum pump to the gas pipe and start the vacuum pump to evacuate the gas, lowering the pressure to below 4 × 10⁻² Pa. Continue evacuating, and then use resistance welding to weld the gas pipes, with three resistance welds on each pipe, each weld 5 mm wide and 20 mm apart between adjacent welds. Remove the vacuum pump, and then use argon arc welding to seal the gas pipe joints. Figure 8 As shown.

[0098] Step 7: Diffusion Welding

[0099] After the sealing welding is completed, layer plate 1 and layer plate 2 are sent into a gas pressurization equipment for gas pressurized diffusion welding. The process parameters are as follows:

[0100] Phase 1: Insulation temperature 1000℃, gas pressure 60MPa, insulation time 4h;

[0101] Phase 2: Insulation temperature 1150℃, gas pressure 15MPa, insulation time 3h.

[0102] Step 8: Machining

[0103] First, the weld seams on the large and small ends of the weldment are removed by machining. Then, machining continues along the inner conical surface of the outer bushing, with a radial removal of 3.65 mm and an axial removal of 4 mm. Finally, a thin layer of 0.05 mm is removed by mechanical grinding, allowing the weldment, inner liner, and outer bushing to separate. Figure 9 As shown, the number of welded plates and microstructures in the resulting layered structure cylinder accounts for approximately 98.2% of the total number, the welding rate of a single plate and microstructure is 95.3%, and the deformation of the layered structure before and after welding is 0.04 mm.

[0104] Matters not covered in this invention are common knowledge.

[0105] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A diffusion welding method for a layered plate structure cylinder, characterized in that: Includes the following steps: Single-piece preparation; outer bushing preparation; cleaning; anti-weld flux application; assembly; evacuation and sealing; diffusion welding; machining; Step 1: Single item preparation; Prepare the single-piece layer 1 (1), single-piece layer 2 (2), and inner lining cylinder to be welded, wherein: (1) The single piece of the layer plate (1) is a high temperature alloy cone with a height of H1, a wall thickness of δ1, an outer diameter of ФA1 at the large end, an outer diameter of ФB1 at the small end, and an array of holes processed on the wall of the cone. (2) The single piece of the layer plate (2) is a high temperature alloy cone. The height of the cone is H2 and H2=H1, the wall thickness is δ2, the outer diameter of the large end is ФA2, the outer diameter of the small end is ФB2, and ФA2-2×δ2=ФA1, ФB2-2×δ2=ФB1. The cone wall is machined with array holes, and the inner surface is arranged with array microstructures. (3) The inner lining cylinder is a high-temperature alloy cone cylinder with the same material as the single piece of the layer plate (2). The cone cylinder height is H3, and H3=H1, the wall thickness is δ3, the outer diameter of the large end is ФA3, the outer diameter of the small end is ФB3, and ФA1-2×δ1=ФA3, ФB1-2×δ1=ФB3; Step 2: Preparation of the outer liner; Prepare an outer bushing. The bushing material is a high-temperature resistant alloy with a coefficient of linear expansion close to that of the base material being welded. Two rows of vent holes are evenly distributed along the height direction of the inner conical surface of the bushing, with 8 vent holes evenly distributed circumferentially in each row. The vent holes are small vent holes with a size of Ф1.0mm on the inner conical surface side of the bushing, and large vent holes with a size of Ф6.0mm on the outer wall side of the bushing. The small and large vent holes are concentric. A stainless steel gas pipe is welded to the inlet side of the large vent hole. The gas pipe has an outer diameter of Ф8.0mm, an inner diameter of Ф6.0mm, and a length that is not limited. There is an alumina diffusion layer with a thickness of 0.03mm-0.05mm on the inner conical surface of the bushing. Step 7: Diffusion welding; After sealing, the single-piece layer 1 (1) and single-piece layer 2 (2) are sent into a gas pressurization equipment for gas pressurized diffusion welding. The process parameters are as follows: Phase 1: Insulation temperature 900℃~1000℃, gas pressure 60MPa~80MPa, insulation time 3h~5h; Phase 2: Insulation temperature 1120℃~1200℃, gas pressure 5MPa~25MPa, insulation time 1.5h~4h.

2. The diffusion welding method for layered plate structure cylinders according to claim 1, characterized in that: Step 3: Cleaning; Pre-treat the surfaces to be welded of single-piece layer 1 (1) and single-piece layer 2 (2) to remove residual oxides, foreign matter, etc.; clean single-piece layer 1 (1), single-piece layer 2 (2) and inner liner cylinder with deionized water; clean the outer liner with clean water.

3. The diffusion welding method for layered plate structure cylinders according to claim 1, characterized in that: Step 4: Apply solder resist; Apply a weld-stopping agent evenly to the outer wall surface of the inner liner cylinder and allow it to air dry.

4. The diffusion welding method for layered plate structure cylinders according to claim 1, characterized in that: Step 5: Assembly; Place the second layer of the shelf, the first layer of the shelf, and the inner liner into the outer liner in sequence, so that the end faces are aligned; use special fusion welding to weld the large and small end faces; step six: evacuate and seal; Connect the vacuum pump to the gas line and start the vacuum pump to evacuate the gas until the pressure is below 4 × 10⁻⁶. -2 Pa; Continue to maintain vacuum, and use resistance welding to weld the gas pipes. There should be no less than 2 resistance welding points on each gas pipe, the width of the welding point should be no less than 3mm, and the center distance between two adjacent welding points should be no less than 15mm; Remove the vacuum pump, and then use argon arc welding to seal the gas pipe joints.

5. The diffusion welding method for layered plate structure cylinders according to claim 1, characterized in that: Step 8: Machining; First, the end face welds of the large and small ends of the weldment are removed by machining. Then, machining continues along the inner conical surface of the outer bushing. The radial removal amount is δ1+δ2+δ3-0.05mm, and the axial removal amount is 2mm-4mm. Finally, the thin layer after 0.05mm is removed by mechanical grinding, so that the weldment, inner liner cylinder and outer bushing are separated. The number of plate-microstructure welds in the resulting layered structure cylinder is greater than 98% of the total number, the weld rate of a single plate-microstructure is greater than 95%, and the deformation of the layered structure before and after welding is no more than 0.05mm.

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