A method for improving the brazing density of wire mesh assemblies

Abstract

This invention relates to a method for improving the density of brazed seams in a chip mesh assembly, belonging to the field of aero-engine technology. The method includes: component preparation; brazing paste preparation; locating welding of one plate of the chip mesh assembly to a filter screen; brazing paste application: applying the prepared brazing paste from step S2 to the surface of the filter screen and compacting it; assembling the other plate of the chip mesh assembly; locating welding the other plate of the chip mesh assembly using a high-temperature alloy foil; a second application of brazing paste: applying the prepared brazing paste to the brazed seam on the end face of the assembly for supplementary coating; vacuum brazing; machining; and visual inspection. This invention is used in the manufacture of chip mesh assemblies, reducing brazed seam porosity and thus improving the density of the brazed seam.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine technology, and particularly relates to a method for improving the density of brazed seams in chip mesh assemblies. Background Technology

[0002] In aero-engines, the chip mesh assembly is a sandwich structure assembly consisting of a plate, a mesh, and another plate, for example... Figure 1 The chip filter assembly shown consists of an inner stainless steel support ring, a middle stainless steel filter screen, and an outer stainless steel frame. The support ring, filter screen, and frame are connected by brazing, and the left and right end faces are machined to ensure the required assembly clearance. During use, it serves to isolate airborne particles, debris, and other impurities.

[0003] Because the filter screen of the filter assembly is made of stainless steel woven mesh, and the diameter of the wire 4 used in the weaving is 0.4mm, the thickness of the resulting filter screen is approximately 0.8mm. Figure 2-3 As shown. Meanwhile, there are assembly gaps of 0.1mm-0.2mm between the filter screen and the support ring and frame. Current brazing methods result in brazing gaps reaching as high as 1.0mm-1.2mm, far exceeding the requirement of no more than 0.15mm. The brazing filler metal cannot effectively fill these gaps, leading to problems such as large weld seam pores and high porosity in the assembled components after machining on the left and right end faces, resulting in a brazing repair rate as high as 40% and a scrap rate as high as 20%. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for improving the density of brazed seams in chip mesh assemblies. The method employs a process route of: single-piece preparation → brazing paste preparation → positioning welding of the frame and filter screen → brazing paste application → support ring assembly → support ring positioning welding → second application of brazing paste → vacuum brazing → machining → visual inspection. This approach reduces brazed seam porosity and porosity, achieving high-density brazing manufacturing of chip mesh assemblies.

[0005] A method for improving the brazing density of a wire mesh assembly specifically includes the following steps:

[0006] S1: Single item preparation

[0007] Gather all the individual parts to be welded and check them for any foreign matter.

[0008] S2: Preparation of solder paste

[0009] S3: Weld one of the plates of the dust collection assembly to the filter screen for positioning.

[0010] S4: Solder paste application

[0011] Apply the brazing paste prepared in step S2 to the surface of the filter screen and compact it;

[0012] S5: Another plate component in the assembly of the chip mesh assembly

[0013] According to the process drawings, assemble another plate onto the part that has been coated with solder paste, with the end faces flush, to form an assembly;

[0014] S6: Tack weld of another plate in the wire mesh assembly

[0015] Clean the brazing filler metal from the end face of the assembly formed in step S5, and then position and weld the high-temperature alloy foil to the end face of the two plates to form a bridge.

[0016] S7: Second application of solder paste

[0017] Apply the prepared brazing paste to the brazing seam on the end face of the assembly for supplementary coating;

[0018] S8: Vacuum brazing

[0019] The chip mesh assembly with additional brazing paste coating was brazed using a general vacuum brazing process.

[0020] S9: Machining

[0021] S10: Visual inspection

[0022] Visual inspection of the machined end face revealed no excessive porosity defects.

[0023] The solder paste in step S2 is a mixture of solder alloy, filler powder and binder.

[0024] The brazing alloy is a commercially available brazing alloy, the filler powder is stainless steel alloy powder of the same type as the component to be welded, and the binder is a commercially available finished binder.

[0025] The proportions of each component in the solder paste are as follows: 40%-50% solder alloy, 40%-50% filler powder, and 10% binder.

[0026] In step S3, if it is a ring assembly, the outer plate is positioned and welded to the filter screen in this step; if it is any other plate-type chip screen assembly, any plate is selected and positioned and welded to the filter screen in this step.

[0027] In step S3, the plates and filter screen are assembled according to the process drawings, and energy storage spot welding is used for positioning welding.

[0028] In step S4, the thickness of the applied solder paste is greater than 1.2 mm.

[0029] The high-temperature alloy foil is 0.3mm thick, 0.6mm wide, and 2mm long. It is spot welded to the end face of the plate using energy storage spot welding. There are 4-6 spot welds evenly distributed on each end face.

[0030] In step S8, a general vacuum brazing process corresponding to the brazing alloy in the brazing paste in step S3 is used.

[0031] In step S9, the end face of the assembly is machined by turning to remove the brazing filler metal buildup.

[0032] The beneficial effects of this invention are: This invention is used in the manufacture of chip mesh assemblies, which can reduce the porosity of brazed seams and improve the density of brazed seams, ensuring that the assemblies meet product quality requirements after machining, and realizing the high-density brazing manufacturing of chip mesh assemblies.

[0033] The method provided by this invention for manufacturing chip mesh assemblies results in a higher density of brazed seams, a first-pass brazing pass rate of up to 90%, and a scrap rate of no more than 5%. Attached Figure Description

[0034] Figure 1 This is a structural schematic diagram of the chip mesh assembly;

[0035] Figure 2 This is a schematic diagram of the filter screen structure;

[0036] Figure 3 for Figure 2 AA view;

[0037] Figure 4 A schematic diagram showing the application of solder paste to the frame and filter screen;

[0038] Figure 5 This is a schematic diagram of the assembly and tack welding of the components in this invention;

[0039] Figure 6 for Figure 5 P-direction schematic diagram;

[0040] in,

[0041] 1-Skeleton, 2-Support ring, 3-Filter screen, 4-Wire, 5-Bronzing paste, 6-Left end face, 7-Right end face, 8-High temperature alloy foil. Detailed Implementation

[0042] To better explain and facilitate understanding of the present invention, the technical solution and effects of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] Example 1

[0044] This embodiment provides a method for improving the brazing density of a chip mesh assembly. The method involves brazing an annular chip mesh assembly composed of a stainless steel support ring 2, a stainless steel filter screen 3, and a stainless steel frame 1. The specific steps include:

[0045] S1: Single item preparation

[0046] Gather the stainless steel support ring 2, stainless steel filter screen 3, and stainless steel frame 1 to be welded, and check that the parts to be welded are free of oil, dirt, or other foreign matter.

[0047] S2: Preparation of solder paste 5

[0048] The brazing alloy, filler powder and binder are mixed evenly to form brazing paste 5.

[0049] The brazing alloy is a commercially available brazing alloy BNi82CrSiB, the filler powder is a stainless steel alloy powder of the same type as the component to be welded, and the binder is a commercially available finished binder.

[0050] The proportions of each component in the solder paste 5 are as follows: 40% solder alloy, 50% filler powder, and 10% binder.

[0051] S3: Position welding of frame 1 and filter screen 3

[0052] Assemble the frame 1 and filter screen 3 according to the process drawings, and use energy storage spot welding to perform positioning welding on the frame 1 and filter screen 3.

[0053] S4: Solder paste 5-coating

[0054] The prepared solder paste 5 from step S2 is applied to the inner ring side of the filter screen 3 and compacted to ensure the thickness of the applied solder paste 5 is greater than 1.2 mm. Figure 4 As shown.

[0055] S5: Support ring 2 assembly

[0056] According to the process drawings, the support ring 2 is assembled onto the skeleton 1 and the filter screen 3 after the solder paste 5 has been applied, so that the end face of the support ring 2 is flush with the end face of the skeleton 1 to form an assembly.

[0057] S6: Positioning weld of support ring 2

[0058] Prepare a high-temperature alloy foil 8 with a thickness of 0.3 mm, a width of 0.6 mm, and a length of 2 mm. Clean the brazing filler metal from the left end face 6 and right end face 7 of the assembly formed in step S5. Use energy storage spot welding to position and weld the high-temperature alloy foil 8 to the end faces of the frame 1 and the support ring 2, forming a bridge. Distribute 6 circumferentially evenly among the positioning welds. Figure 5-6 As shown.

[0059] S7: Second application of solder paste 5

[0060] Apply the prepared solder paste 5 to the brazing seam on the left end face 6 and the right end face 7 for supplementary coating.

[0061] S8: Vacuum brazing

[0062] The chip mesh assembly with supplementary brazing paste 5 was brazed using the BNi82CrSiB general vacuum brazing process.

[0063] S9: Machining

[0064] The left end face 6 and the right end face 7 are machined by turning to remove the brazing filler metal buildup.

[0065] S10: Visual inspection

[0066] Visual inspection of the machined left end face 6 and right end face 7 revealed no excessive porosity defects.

[0067] Example 2

[0068] This embodiment provides a method for improving the brazing density of a chip mesh assembly. The method involves brazing an annular chip mesh assembly composed of a stainless steel support ring 2, a stainless steel filter screen 3, and a stainless steel frame 1. The specific steps include:

[0069] S1: Single item preparation

[0070] Gather the stainless steel support ring 2, stainless steel filter screen 3, and stainless steel frame 1 to be welded, and check that the parts to be welded are free of oil, dirt, or other foreign matter.

[0071] S2: Preparation of solder paste 5

[0072] The brazing alloy, filler powder and binder are mixed evenly to form brazing paste 5.

[0073] The brazing alloy is a commercially available brazing alloy BNi82CrSiB, the filler powder is pure nickel powder, and the binder is a commercially available finished binder.

[0074] The proportions of each component in the solder paste 5 are as follows: 50% solder alloy, 40% filler powder, and 10% binder.

[0075] S3: Position welding of frame 1 and filter screen 3

[0076] Assemble the frame 1 and filter screen 3 according to the process drawings, and use energy storage spot welding to perform positioning welding on the frame 1 and filter screen 3.

[0077] S4: Solder paste 5-coating

[0078] The prepared solder paste 5 from step S2 is applied to the inner ring side of the filter screen 3 and compacted to ensure the thickness of the applied solder paste 5 is greater than 1.2 mm. Figure 4 As shown.

[0079] S5: Support ring 2 assembly

[0080] According to the process drawings, the support ring 2 is assembled onto the skeleton 1 and the filter screen 3 after the solder paste 5 has been applied, so that the end face of the support ring 2 is flush with the end face of the skeleton 1 to form an assembly.

[0081] S6: Positioning weld of support ring 2

[0082] Prepare a high-temperature alloy foil 8 with a thickness of 0.3 mm, a width of 0.6 mm, and a length of 2 mm. Clean the brazing filler metal from the left end face 6 and right end face 7 of the assembly formed in step S5. Use energy storage spot welding to position and weld the high-temperature alloy foil 8 to the end faces of the frame 1 and the support ring 2, forming a bridge. Distribute 6 circumferentially evenly among the positioning welds. Figure 5-6 As shown.

[0083] S7: Second application of solder paste 5

[0084] Apply the prepared solder paste 5 to the brazing seam on the left end face 6 and the right end face 7 for supplementary coating.

[0085] S8: Vacuum brazing

[0086] The chip mesh assembly with supplementary brazing paste 5 was brazed using the BNi82CrSiB general vacuum brazing process.

[0087] S9: Machining

[0088] The left end face 6 and the right end face 7 are machined by turning to remove the brazing filler metal buildup.

[0089] S10: Visual inspection

[0090] Visual inspection of the machined left end face 6 and right end face 7 revealed no excessive porosity defects.

Claims

1. A method for improving the brazing density of a wire mesh assembly, characterized in that, Specifically, the following steps are included: S1: Single item preparation Gather all the individual parts to be welded and check them for any foreign matter. S2: Preparation of solder paste S3: Weld one of the plates of the dust collection assembly to the filter screen for positioning. S4: Solder paste application Apply the brazing paste prepared in step S2 to the surface of the filter screen and compact it; S5: Another plate component in the assembly chip mesh assembly According to the process drawings, assemble another plate onto the part that has been coated with solder paste, with the end faces flush, to form an assembly; S6: Tack weld of another plate in the wire mesh assembly Clean the brazing filler metal from the end face of the assembly formed in step S5, and then position and weld the high-temperature alloy foil to the end face of the two plates to form a bridge. S7: Second application of solder paste Apply the prepared brazing paste to the brazing seam on the end face of the assembly for supplementary coating; S8: Vacuum brazing The chip mesh assembly with additional brazing paste coating was brazed using a general vacuum brazing process. S9: Machining S10: Visual inspection Visual inspection of the machined end face revealed no excessive porosity defects.

2. The method for improving the brazing density of a wire mesh assembly according to claim 1, characterized in that: The solder paste in step S2 is a mixture of solder alloy, filler powder and binder.

3. The method for improving the brazing density of a wire mesh assembly according to claim 2, characterized in that: The brazing alloy is a commercially available brazing alloy, the filler powder is stainless steel alloy powder of the same type as the component to be welded, and the binder is a commercially available finished binder.

4. The method for improving the brazing density of a wire mesh assembly according to claim 2, characterized in that: The proportions of each component in the solder paste are as follows: 40%-50% solder alloy, 40%-50% filler powder, and 10% binder.

5. The method for improving the brazing density of a wire mesh assembly according to claim 1, characterized in that: In step S3, if it is a ring assembly, the outer plate is positioned and welded to the filter screen in this step; if it is any other plate-type chip screen assembly, any plate is selected and positioned and welded to the filter screen in this step.

6. The method for improving the brazing density of a wire mesh assembly according to claim 5, characterized in that: In step S3, the plates and filter screen are assembled according to the process drawings, and energy storage spot welding is used for positioning welding.

7. The method for improving the brazing density of a wire mesh assembly according to claim 1, characterized in that: In step S4, the thickness of the applied solder paste is greater than 1.2 mm.

8. The method for improving the brazing density of a wire mesh assembly according to claim 1, characterized in that: The high-temperature alloy foil is 0.3mm thick, 0.6mm wide, and 2mm long. It is spot welded to the end face of the plate using energy storage spot welding. There are 4-6 spot welds evenly distributed on each end face.

9. The method for improving the brazing density of a wire mesh assembly according to claim 1, characterized in that: In step S8, a general vacuum brazing process corresponding to the brazing alloy in the brazing paste in step S3 is used.

10. The method for improving the brazing density of a wire mesh assembly according to claim 1, characterized in that: In step S9, the end face of the assembly is machined by turning to remove the brazing filler metal buildup.

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