A low-melting-point repair solder for high-temperature nickel-based alloy honeycomb repair and its preparation method

Abstract

This invention relates to a low-melting-point repair solder for high-temperature nickel-based alloy honeycomb repair and its preparation method. The chemical composition of the repair solder is as follows (mass percentage): Au: 10-20%, Cr: 5.6-7.2%, B: 2.5-3.15%, Si: 3.6-4.5%, Ge: 1.0-1.5%, with the balance being Ni. The preparation method includes the following steps: preparing the repair solder into amorphous flakes, powder, or solder paste. The application method includes: cleaning the damaged area, fabricating the repair part, and performing brazing repair using the repair solder. The technical solution of this invention completely repairs honeycomb brazing defects, ensuring stable repair conditions, good strength, and compliance with technical requirements, resulting in a high success rate for honeycomb brazing repair. Compared to replacing with a new product, using the repair solder and process of this invention for honeycomb repair saves on the cost per part.

Description

Technical Field

[0001] This invention relates to the field of metal brazing technology, specifically to a low-melting-point repair brazing filler metal for high-temperature nickel-based alloy honeycomb repair welding and its preparation method. Background Technology

[0002] As a typical lightweight structure, honeycomb structures are widely used in the sealing structures of aero-engines. They possess excellent spatial geometry and superior mechanical properties. Compared to other structures made of the same material, they combine high specific strength, high specific stiffness, high strength and toughness, good impact resistance, and unique properties such as sound absorption and energy storage, heat dissipation and vibration damping, and electromagnetic shielding. Furthermore, honeycomb structures are easy to manufacture, making them ideal for use in components with complex shapes.

[0003] Aero-engine sealing structures are often fabricated using high-temperature alloy honeycomb and high-temperature alloy plates via vacuum brazing. During the brazing process, localized honeycomb damage and welding defects are prone to occur. Currently, the method of powdering the original brazing filler metal and then remelting it is used to repair the defective areas. This repair method not only reduces the strength of the original honeycomb material but may also cause the original braze seam to remelt. Therefore, it is very important to find a new low-melting-point repair brazing filler metal and repair method. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a low-melting-point repair solder for high-temperature nickel-based alloy honeycomb welding and its preparation method; the specific technical solution is as follows:

[0005] A low-melting-point brazing filler metal for repairing high-temperature nickel-based alloy honeycomb has the following chemical composition by mass percentage: Au: 10-20%, Cr: 5.6-7.2%, B: 2.5-3.15%, Si: 3.6-4.5%, Ge: 1.0-1.5%, with the balance being Ni.

[0006] A low-melting-point solder for repairing high-temperature nickel-based alloy honeycomb, wherein the preferred embodiment is to mix low-melting-point nickel-based alloy powder and binder evenly to form solder paste;

[0007] The binder is used to improve the fluidity of the brazing filler metal, making it easier to apply to the workpiece, and also to remove oxides from the surface of the base material and the brazing filler metal.

[0008] The preferred embodiment of the method for preparing a low-melting-point brazing filler metal for repairing high-temperature nickel-based alloy honeycomb is as follows: The preparation method of the low-melting-point brazing filler metal includes the following steps:

[0009] Step 1: Weigh each raw material according to the mass percentage, ultrasonically clean each raw material in acetone solution for 15 minutes, then ultrasonically clean it in alcohol solution for 5 minutes, and dry it for later use.

[0010] Step 2: Mix the nickel, chromium, gold, silicon, boron, and germanium raw materials evenly, place them in a vacuum arc melting furnace, evacuate to a low vacuum, fill with argon gas, and melt repeatedly 4 times to obtain a nickel-based alloy ingot. After cooling, remove it from the vacuum arc melting furnace, grind off the surface metal dross, and obtain the gold-containing low-melting-point repair solder.

[0011] The preferred embodiment of the method for preparing a low-melting-point brazing filler metal for repairing high-temperature nickel-based alloy honeycomb is that, in step one, the concentration of the acetone solution is 99.5%.

[0012] The preferred embodiment of the method for preparing a low-melting-point brazing filler metal for repairing high-temperature nickel-based alloy honeycomb is that, in step two, the vacuum degree of the low vacuum evacuation is 1×10⁻⁶. -1 Pa, the repeated melting is spaced 5 minutes apart, the melting temperature is 1200℃-1300℃, and the melting time is 10-30 minutes, so as to allow the elements to fully diffuse and fuse.

[0013] The preferred embodiment of the method for preparing a low-melting-point brazing filler metal for repairing high-temperature nickel-based alloy honeycomb is a method for using the low-melting-point gold-containing brazing filler metal, comprising the following steps:

[0014] Step 1: Use a cutting machine to clean out the area to be repaired and process the corresponding repair patch. The size of the patch should be larger than the size of the area to be repaired, but not too large. L is 0.3-0.5 times the honeycomb radius.

[0015] Step 2: Clean, grind, and acid-wash the area to be repaired and the patch to remove oil and oxide film from the material surface;

[0016] Step 3: Install the patch on the area to be repaired, carefully adjust its position, and apply solder paste or insert brazing foil into the gap between the patch and the original honeycomb.

[0017] Step 4: Place the assembled honeycomb and brazing filler metal into a high-temperature brazing furnace for welding. The welding parameters are 980℃ / 60min and a vacuum degree of 3×10⁻⁶. -3 Pa;

[0018] Step 5: After brazing, clean the brazing seam to remove any residual brazing filler metal and flux.

[0019] Compared with the prior art, the present invention has the following beneficial technical effects:

[0020] The technical solution adopted in this invention ensures a stable composition ratio of gold-containing low-melting-point repair solder, free from excessive impurities. The binder improves the fluidity of the solder, facilitating its application to the workpiece, while also removing oxides from the base material and solder surfaces, thus improving welding quality.

[0021] This invention facilitates the preparation of a low-melting-point gold-containing repair brazing filler metal that can be used to repair nickel-based high-temperature alloy honeycomb. Compared with the traditional high-melting-point brazing filler metal powdering repair method, this method simultaneously ensures the strength of the honeycomb base material and the original weld after repair.

[0022] The method of this invention is applied in the repair of honeycomb sealing structures of aero engines, which completely repairs honeycomb brazing defects and faults. The repaired position is stable, the strength is good, and it meets the technical requirements, thereby improving the pass rate of honeycomb brazing repair. Attached Figure Description

[0023] Figure 1 The high-temperature nickel-based alloy tensile curves are shown in the examples.

[0024] Figure 2 This is a schematic diagram illustrating the process of cleaning the damaged area and creating a patch, as shown in the example.

[0025] Figure 3 This is a schematic diagram of the assembly patch and filler solder in an embodiment. Detailed Implementation

[0026] The following is in conjunction with the appendix Figure 1-3 The present invention will be described in detail, but the scope of protection of the present invention is not limited by the accompanying drawings.

[0027] Example 1

[0028] A method for preparing a low-melting-point brazing filler metal for repairing honeycomb structures in high-temperature nickel-based alloys includes the following steps:

[0029] Step 1: Prepare the solder: Au: 10%, Cr: 6%, B: 2.5%, Si: 4%, Ge: 1%, balance Ni. Weigh out the various high-purity raw materials according to the above mass percentages, ensuring that the purity of each high-purity raw material is not less than 99.99%.

[0030] Step 2: Weigh each raw material according to the mass percentage, and ultrasonically clean each raw material in acetone solution for 15 minutes, then ultrasonically clean it in alcohol solution for 5 minutes, and dry it for later use; wherein the concentration of the acetone solution is 99.5%;

[0031] Step 3: Mix the nickel, chromium, gold, silicon, boron, and germanium raw materials evenly, place them in a vacuum arc melting furnace, evacuate to a low vacuum, fill with argon gas, and repeat the melting process four times to obtain a nickel-based alloy ingot. After cooling, remove it from the vacuum arc melting furnace, polish to remove surface metal dross, and obtain the gold-containing low-melting-point repair solder; the vacuum degree of the low vacuum is 1×10⁻⁶. -1Pa, the repeated melting is spaced 5 minutes apart, the melting temperature is 1200℃-1300℃, and the melting time is 10min-30min, so as to allow the elements to fully diffuse and fuse.

[0032] Step 4: The bulk alloy is made into amorphous thin sheets. The amorphous thin sheets are prepared by single-roll quenching and the thickness of the amorphous thin sheets is 50 μm.

[0033] Step 5: Assemble the nickel-based alloy plate and brazing filler metal and place them in a high-temperature brazing furnace for welding. The welding parameters are 980℃ / 60min and a vacuum degree of 3×10⁻⁶. -3 Pa.

[0034] Step 6: After welding, a tensile test is performed on the sample. The tensile strength can reach about 600 MPa, indicating that the welding quality is good.

[0035] Example 2

[0036] A method for preparing a low-melting-point brazing filler metal for repairing honeycomb structures in high-temperature nickel-based alloys includes the following steps:

[0037] Step 1: Prepare the solder, with the following composition: Au: 20%, Cr: 7%, B: 3%, Si: 4.5%, Ge: 1.5%, and the balance being Ni. Weigh out the various high-purity raw materials according to the above mass percentages, ensuring that the purity of each high-purity raw material is not less than 99.99%.

[0038] Step 2: Weigh each raw material according to the mass percentage, and ultrasonically clean each raw material in acetone solution for 15 minutes, then ultrasonically clean it in alcohol solution for 5 minutes, and dry it for later use; the concentration of the acetone solution is 99.5%;

[0039] Step 3: Mix the nickel, chromium, gold, silicon, boron, and germanium raw materials evenly, place them in a vacuum arc melting furnace, draw a low vacuum, fill with argon gas, and melt repeatedly four times to obtain a nickel-based alloy ingot. After cooling, take it out of the vacuum arc melting furnace, grind off the surface metal dross, and obtain the gold-containing low-melting-point repair brazing filler metal.

[0040] The vacuum level of the evacuation is 1×10⁻⁶. -1 Pa, the repeated melting is spaced 5 minutes apart, the melting temperature is 1200℃-1300℃, and the melting time is 10-30 minutes, so as to allow the elements to fully diffuse and fuse;

[0041] Step 4: The bulk alloy is made into amorphous thin sheets. The amorphous thin sheets are prepared by single-roll quenching and the thickness of the amorphous thin sheets is 50 μm.

[0042] Step 5: Fabrication of welding test blocks: The nickel-based alloy honeycomb test block is 100x100 mm in size, the area to be repaired is 50x50 mm in size, and the honeycomb size is 12.8 mm; the patch block is 55x55 mm in size, and the honeycomb size is consistent with the material to be repaired;

[0043] Step Six: Assemble the patch block with the cell to be repaired, adjust its position, and place the brazing foil between the two test blocks;

[0044] Step 7: The honeycomb structure and brazing filler metal are placed in a high-temperature brazing furnace for welding. The welding parameters are 980℃ / 60min and a vacuum degree of 3×10⁻⁶. -3 Pa.

[0045] Step 8: After welding is completed, the weld quality is tested. No cracks were found in any of the welds, and the welding quality is good.

Claims

1. A method for preparing a low-melting-point brazing filler metal for repairing high-temperature nickel-based alloy honeycomb, characterized in that: The chemical composition of the low-melting-point solder, by mass percentage, is as follows: Au: 10~20%, Cr: 5.6~7.2%, B: 2.5~3.15%, Si: 3.6~4.5%, Ge: 1.0~1.5%, with the balance being Ni; The preparation method of low-melting-point solder includes the following steps: Step 1: Weigh each raw material according to the mass percentage, and ultrasonically clean each raw material in acetone solution for 15 minutes, then ultrasonically clean it in alcohol solution for 5 minutes, and dry it for later use. Step 2: Mix the nickel, chromium, gold, silicon, boron, and germanium raw materials evenly, place them in a vacuum arc melting furnace, draw a low vacuum, fill with argon gas, and melt repeatedly 4 times to obtain a nickel-based alloy ingot. After cooling, take it out of the vacuum arc melting furnace, grind off the surface metal dross, and obtain the low melting point repair brazing filler metal. The method for using low-melting-point gold-containing solder includes the following steps: Step 1: Use a cutting machine to clean out the area to be repaired and process the corresponding repair patch. The size of the patch is larger than the size of the area to be repaired, where L is 0.3-0.5 times the honeycomb radius. Step 2: Clean, grind, and acid-wash the area to be repaired and the patch to remove oil and oxide film from the material surface; Step 3: Install the patch on the area to be repaired, carefully adjust its position, and apply solder paste or insert brazing foil into the gap between the patch and the original honeycomb. Step 4: Place the assembled honeycomb and brazing filler metal into a high-temperature brazing furnace for welding. The welding parameters are 980℃ / 60min and a vacuum degree of 3×10⁻⁶. -3 Pa; Step 5: After brazing, clean the brazing seam to remove any residual brazing filler metal and flux.

2. The method for preparing a low-melting-point brazing filler metal for repairing high-temperature nickel-based alloy honeycomb according to claim 1, characterized in that: Low-melting-point nickel-based alloy powder and binder are mixed evenly to form solder paste; The binder is used to improve the fluidity of the brazing filler metal, making it easier to apply to the workpiece, and also to remove oxides from the surface of the base material and the brazing filler metal.

3. The method for preparing a low-melting-point brazing filler metal for repairing high-temperature nickel-based alloy honeycomb according to claim 1, characterized in that: The concentration of the acetone solution is 99.5%.

4. The method for preparing a low-melting-point brazing filler metal for repairing high-temperature nickel-based alloy honeycomb according to claim 1, characterized in that: The vacuum level of the evacuation is 1×10⁻⁶. -1 Pa, the repeated melting is spaced 5 minutes apart, the melting temperature is 1200℃-1300℃, and the melting time is 10-30 minutes, so as to allow the elements to fully diffuse and fuse.

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