Method for improving compactness of brazing seam of chip net assembly

Abstract

The invention relates to a method for improving compactness of a brazing seam of a chip net assembly, and belongs to the technical field of aero-engines. Preparing brazing paste; the brazing paste coating is conducted, specifically, the surface of the filter screen is coated with the brazing paste prepared in the step S2, and the brazing paste is compacted; the other plate in the chip net assembly is assembled; performing positioned welding on the other plate in the chip net assembly through the high-temperature alloy foil; coating the brazing paste for the second time: coating the prepared brazing paste into a brazing seam on the end surface of the assembly for supplementary coating; performing vacuum brazing; lathing is conducted; and performing visual inspection. The method is used for manufacturing the chip net assembly, and can reduce pores of a brazing seam and reduce the porosity of the brazing seam, so that the compactness of the brazing seam is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of aviation engines, and in particular relates to a method for improving the density of a brazing seam of a chip net assembly. Background Art

[0002] In aircraft engines, the chip net assembly is a sandwich structure assembly of plate + net + plate, for example Figure 1 The chip screen assembly shown is composed of a stainless steel support ring in the inner ring, a stainless steel filter screen in the middle and a stainless steel frame in the outer ring. The support ring, filter screen and frame are connected by brazing, and then the left and right end faces are machined by lathing to ensure the assembly clearance requirements. It plays a role in isolating impurities such as particles and debris in the air during use.

[0003] Since the filter screen of the dust screen assembly is a stainless steel woven screen, the diameter of the wire 4 used for weaving is 0.4 mm, and the thickness of the filter screen formed after weaving is about 0.8 mm. Figure 2-3 At the same time, there is a 0.1mm-0.2mm assembly gap between the filter screen and the support ring and the frame. The current brazing method results in a brazing gap of up to 1.0mm-1.2mm, far exceeding the requirement that the brazing assembly gap does not exceed 0.15mm. The brazing material cannot effectively fill the gap, resulting in large brazing seam pores and high porosity in the assembly after machining on the left and right end faces. The brazing repair rate is as high as 40%, and the scrap rate is as high as 20%. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a method for improving the density of the brazing seam of a chip net assembly. The present invention proposes a method for improving the density of the brazing seam of a chip net assembly, adopting a process route of single-piece preparation → brazing paste preparation → skeleton and filter net positioning welding → brazing paste coating → support ring assembly → support ring positioning welding → second coating of brazing paste → vacuum brazing → turning → visual inspection, thereby reducing the porosity of the brazing seam and the porosity of the brazing seam, and realizing high-density brazing manufacturing of the chip net assembly.

[0005] A method for improving the density of a brazing seam of a chip net assembly comprises the following steps:

[0006] S1: Single piece preparation

[0007] Gather all the parts to be welded and check that there is no heterogeneity in the parts to be welded;

[0008] S2: Brazing paste preparation

[0009] S3: Position weld one of the plates of the chip screen assembly to the filter screen:

[0010] S4: Solder paste application

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

[0012] S5: Assemble the other plate in the chip screen assembly

[0013] According to the process drawing, assemble another plate onto the part coated with brazing paste, with the end faces flush to form an assembly;

[0014] S6: Position welding of another plate in the chip net assembly

[0015] Clean the brazing material on the end surface of the assembly formed in step S5, and position-weld the high-temperature alloy foil to the end surfaces of the two plates to form a bridge;

[0016] S7: Second application of solder paste

[0017] Applying the prepared solder paste to the solder joint of the end face of the assembly for supplementary coating;

[0018] S8: Vacuum brazing

[0019] The chip net assembly supplemented with brazing paste is brazed using a common vacuum brazing process;

[0020] S9: Turning

[0021] S10: Visual inspection

[0022] Visually inspect the machined end face to ensure that there are no excessive porosity defects.

[0023] The solder paste in step S2 is formed by uniformly mixing solder alloy, filling powder and binder.

[0024] The solder alloy is a commercial solder alloy, the filling powder is a stainless steel alloy powder of the same quality as the single piece to be welded, and the binder is a commercial finished product binder.

[0025] The proportions of the components in the solder paste are as follows: solder alloy accounts for 40%-50%, filling powder accounts for 40%-50%, and binder accounts for 10%.

[0026] In step S3, if it is an annular assembly, in this step, the outer plate is welded to the filter screen; if it is other plate-type dust screen assemblies, in this step, any one plate is welded to the filter screen;

[0027] In step S3, the plate and the filter are assembled according to the process drawings, and the positioning welding is performed by energy storage spot welding.

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

[0029] The high temperature alloy foil has a thickness of 0.3 mm, a width of 0.6 mm, and a length of 2 mm, and is positioned welded to the end face of the plate by energy storage spot welding; 4-6 positioning welds are evenly distributed on each end face.

[0030] The step S8 adopts a general vacuum brazing process corresponding to the brazing alloy in the brazing paste in step S3.

[0031] In step S9, the end surface of the assembly is machined by turning to remove the solder accumulation.

[0032] The beneficial effects of the present invention are as follows: the present invention is used for manufacturing chip net assemblies, which can reduce the pores of the brazing seams and the porosity of the brazing seams, thereby improving the density of the brazing seams, ensuring that the assemblies meet the product quality requirements after mechanical processing, and realizing high-density brazing manufacturing of chip net assemblies.

[0033] By adopting the method provided by the invention to manufacture the chip net assembly, the brazing seam formed has higher density, the first-time brazing qualified rate is as high as 90%, and the scrap rate does not exceed 5%. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a structural schematic diagram of a chip net assembly;

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

[0036] Figure 3 for Figure 2 AA view;

[0037] Figure 4 Schematic diagram of applying solder paste to the frame and filter screen;

[0038] Figure 5 It is a schematic diagram of the assembly positioning welding of the assembly in the present 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-brazing paste, 6-left end surface, 7-right end surface, 8-high temperature alloy foil. DETAILED DESCRIPTION

[0042] In order to better explain the present invention and facilitate understanding, the technical solutions and effects of the present invention are described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0043] Example 1

[0044] This embodiment provides a method for improving the density of the brazing seam of a chip net assembly, wherein the annular chip net assembly composed of a stainless steel support ring 2, a stainless steel filter net 3 and a stainless steel frame 1 is brazed, specifically comprising the following steps:

[0045] S1: Single piece preparation

[0046] Gather the stainless steel support ring 2, stainless steel filter 3 and stainless steel skeleton 1 to be welded, and check whether the single piece to be welded is free of foreign matter such as oil and dirt.

[0047] S2: Preparation of solder paste 5

[0048] The solder alloy, filler powder and binder are mixed uniformly to form a solder paste 5 .

[0049] The solder alloy is a commercial solder alloy BNi82CrSiB, the filling powder is a stainless steel alloy powder of the same quality as the single piece to be welded, and the binder is a commercial finished product binder.

[0050] The proportions of the components in the solder paste 5 are as follows: solder alloy accounts for 40%, filling powder accounts for 50%, and binder accounts for 10%.

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

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

[0053] S4: Solder paste 5 coating

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

[0055] S5: Support ring 2 assembly

[0056] According to the process drawing, the support ring 2 is assembled onto the frame 1 and the filter screen 3 coated with the solder paste 5, so that the end face of the support ring 2 is flush with the end face of the frame 1 to form an assembly.

[0057] S6: Support ring 2 positioning welding

[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 on the left end face 6 and the right end face 7 of the assembly formed in step S5. Use energy storage spot welding to position weld the high-temperature alloy foil 8 to the end faces of the skeleton 1 and the support ring 2 to form a bridge. Position weld 6 locations are evenly distributed around the circumference. Figure 5-6 shown.

[0059] S7: Second application of solder paste 5

[0060] The prepared solder paste 5 is applied to the soldering seams of the left end face 6 and the right end face 7 for supplementary coating.

[0061] S8: Vacuum brazing

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

[0063] S9: Turning

[0064] The left end face 6 and the right end face 7 are machined by turning to remove the accumulation of solder.

[0065] S10: Visual inspection

[0066] Visually inspect the left end face 6 and the right end face 7 after machining, and find that there are no excessive porosity defects.

[0067] Example 2

[0068] This embodiment provides a method for improving the density of the brazing seam of a chip net assembly, wherein the annular chip net assembly composed of a stainless steel support ring 2, a stainless steel filter net 3 and a stainless steel frame 1 is brazed, specifically comprising the following steps:

[0069] S1: Single piece preparation

[0070] Gather the stainless steel support ring 2, stainless steel filter 3 and stainless steel skeleton 1 to be welded, and check whether the single piece to be welded is free of foreign matter such as oil and dirt.

[0071] S2: Preparation of solder paste 5

[0072] The solder alloy, filler powder and binder are mixed uniformly to form a solder paste 5 .

[0073] The solder alloy is a commercial solder alloy BNi82CrSiB, the filling powder is a single pure nickel powder, and the binder is a commercial finished product binder.

[0074] The proportions of the components in the solder paste 5 are as follows: solder alloy accounts for 50%, filling powder accounts for 40%, and binder accounts for 10%.

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

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

[0077] S4: Solder paste 5 coating

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

[0079] S5: Support ring 2 assembly

[0080] According to the process drawing, the support ring 2 is assembled onto the frame 1 and the filter screen 3 coated with the solder paste 5, so that the end face of the support ring 2 is flush with the end face of the frame 1 to form an assembly.

[0081] S6: Support ring 2 positioning welding

[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 on the left end face 6 and the right end face 7 of the assembly formed in step S5. Use energy storage spot welding to position weld the high-temperature alloy foil 8 to the end faces of the skeleton 1 and the support ring 2 to form a bridge. Position weld 6 locations are evenly distributed around the circumference. Figure 5-6 shown.

[0083] S7: Second application of solder paste 5

[0084] The prepared solder paste 5 is applied to the soldering seams of the left end face 6 and the right end face 7 for supplementary coating.

[0085] S8: Vacuum brazing

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

[0087] S9: Turning

[0088] The left end face 6 and the right end face 7 are machined by turning to remove the accumulation of solder.

[0089] S10: Visual inspection

[0090] Visually inspect the left end face 6 and the right end face 7 after machining, and find that there are no excessive porosity defects.

Claims

1. A method for improving the density of brazing seams of chip net assemblies, characterized in that: The specific steps include: S1: Single piece preparation Gather all the parts to be welded and check that there is no heterogeneity in the parts to be welded; S2: Brazing paste preparation S3: Position weld one of the plates of the chip screen assembly to the filter screen: S4: Solder paste application Apply the solder paste prepared in step S2 to the surface of the filter screen and compact it; S5: Assemble the other plate in the chip screen assembly According to the process drawing, assemble another plate onto the part coated with brazing paste, with the end faces flush to form an assembly; S6: Position welding of another plate in the chip net assembly Clean the brazing material on the end surface of the assembly formed in step S5, and position-weld the high-temperature alloy foil to the end surfaces of the two plates to form a bridge; S7: Second application of solder paste Applying the prepared solder paste to the solder joint of the end face of the assembly for supplementary coating; S8: Vacuum brazing The chip net assembly supplemented with brazing paste is brazed using a common vacuum brazing process; S9: Turning S10: Visual inspection Visually inspect the machined end face to ensure that there are no excessive porosity defects.

2. A method for improving the density of brazing seams of chip net assemblies according to claim 1, characterized in that: The solder paste in step S2 is formed by uniformly mixing solder alloy, filling powder and binder.

3. A method for improving the density of brazing seams of chip net assemblies according to claim 2, characterized in that: The solder alloy is a commercial solder alloy, the filling powder is a stainless steel alloy powder of the same quality as the single piece to be welded, and the binder is a commercial finished product binder.

4. A method for improving the density of brazing seams of chip net assemblies according to claim 2, characterized in that: The proportions of the components in the solder paste are as follows: solder alloy accounts for 40%-50%, filling powder accounts for 40%-50%, and binder accounts for 10%.

5. A method for improving the density of brazing seams of chip net assemblies according to claim 1, characterized in that: In step S3, if it is an annular assembly, in this step, the outer plate is tack welded to the filter screen; if it is other plate-type dust screen assemblies, in this step, any one plate is selected to be tack welded to the filter screen.

6. A method for improving the density of brazing seams of chip net assemblies according to claim 5, characterized in that: In step S3, the plate and the filter are assembled according to the process drawings, and the positioning welding is performed by energy storage spot welding.

7. A method for improving the density of brazing seams of chip net assemblies according to claim 1, characterized in that: In the step S4, the thickness of the applied solder paste is greater than 1.2 mm.

8. A method for improving the density of brazing seams of chip net assemblies according to claim 1, characterized in that: The high temperature alloy foil has a thickness of 0.3 mm, a width of 0.6 mm, and a length of 2 mm, and is positioned welded to the end face of the plate by energy storage spot welding; 4-6 positioning welds are evenly distributed on each end face.

9. A method for improving the density of brazing seams of chip net assemblies according to claim 1, characterized in that: The step S8 adopts a general vacuum brazing process corresponding to the brazing alloy in the brazing paste in step S3.

10. A method for improving the density of brazing seams of chip net assemblies according to claim 1, characterized in that: In step S9, the end surface of the assembly is machined by turning to remove the solder accumulation.

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