Preparation and application method of low-melting-point brazing filler metal for repairing aluminum alloy honeycomb damage

Abstract

The invention relates to preparation of low-melting-point brazing filler metal for repairing aluminum alloy honeycomb damage and an application method of the low-melting-point brazing filler metal. The low-melting-point brazing filler metal is prepared from, by mass, 5%-12% of Mg, 5%-13% of Cu, 10%-40% of Zn, 1.5%-4.5% of Sn, 2.0%-6.0% of Ge, 4.5%-12.5% of Si and the balance Al. The preparation method comprises the following steps: preparing the low-melting-point repair brazing filler metal into an amorphous sheet, powder or soldering paste; the using method comprises the steps that damaged parts are cleaned, repaired parts are manufactured, and the low-melting-point repairing brazing filler metal is used for conducting brazing repairing. According to the method, the melting reduction effect of Mg, Cu, Zn, Sn, Ge and Si elements is facilitated, the low-melting-point brazing filler metal capable of being used for repairing the aluminum alloy honeycomb is prepared, and compared with a traditional glue pouring repairing method, the method guarantees the strength and the light weight of the repaired honeycomb at the same time.

Description

Technical Field

[0001] The invention relates to the technical field of metal brazing, and in particular to a preparation method and an application method of a low-melting-point brazing filler metal for repairing aluminum alloy honeycomb damage. Background Art

[0002] Honeycomb materials have a very low density and are therefore very light, which helps reduce the overall weight of the aircraft. At the same time, they have high strength and can withstand greater pressure and impact. Honeycomb materials also have excellent corrosion resistance, which can meet the long-term use requirements of aircraft in harsh environments. In addition, honeycombs are very easy to process, which makes them very suitable for use in parts with complex shapes. Due to these advantages, honeycomb materials are widely used in aircraft.

[0003] However, in the long-term use process, the honeycomb parts are inevitably hit by foreign objects, resulting in damage, honeycomb collapse, corrosion, etc. At present, the honeycomb is repaired by filling the honeycomb core with glue. This repair method not only fails to meet the strength requirements of the original honeycomb material, but also greatly increases the weight of the aircraft. Therefore, it is very important to find a new repair method that can take into account both weight and strength. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a preparation method and application method of a low melting point solder for repairing aluminum alloy honeycomb damage; the specific technical scheme is as follows: A method for preparing a low melting point solder for repairing aluminum alloy honeycomb damage comprises the following steps: Step 1: The chemical composition mass percentages of the low melting point solder are: Mg: 5-12%, Cu: 5-13%, Zn: 10-40%, Sn: 1.5-4.5%, Ge: 2.0-6.0%, Si: 4.5-12.5%, and the balance is Al; Weigh various high-purity raw materials according to the mass percentage of the chemical composition of the solder, and the purity of the various high-purity raw materials is not less than 99.99%; Step 2: Divide the Al raw material into three parts, namely, the first part, the second part and the third part; wherein the first part is combined with Ge to form an Al-Ge compound, and the second part is combined with Si to form an Al-Si compound; Step 3: Evenly mix the third part of Al raw material, Mg raw material, Cu raw material, Zn raw material, Sn raw material, Al-Ge compound and Al-Si compound, heat and melt them in an arc furnace under an argon protective atmosphere to obtain a block alloy, i.e. the above-mentioned low-melting-point repair solder.

[0005] The method for preparing a low-melting-point solder for repairing aluminum alloy honeycomb damage is preferably as follows: in step 2, the mass ratio of the first part of Al raw material, the second part of Al raw material and the third part of Al raw material depends on the specific composition of the solder.

[0006] The method for preparing a low-melting-point solder for repairing aluminum alloy honeycomb damage is preferably as follows: in step three, the melting temperature of the electric arc furnace is 700°C and the melting time is 5min-10min, so as to facilitate full diffusion and fusion of the elements while avoiding element loss.

[0007] The method for preparing a low-melting-point solder for repairing aluminum alloy honeycomb damage is preferably as follows: in step three, the block alloy is made into an amorphous sheet, the amorphous sheet is prepared by a single-roller rapid cooling method, and the thickness of the amorphous sheet is 50 μm.

[0008] A method for applying a low melting point solder for repairing aluminum alloy honeycomb damage comprises the following steps: Step 1: Use a cutting machine to clean 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. Step 2: Clean, polish, and pickle the repaired area and patch to remove oil and oxide film on the surface of the material; Step 3: Install the patch on the area to be repaired, carefully adjust the position, and apply solder paste or put solder foil into the gap between the patch and the original honeycomb; Step 4: Use special repair tools or flame, hot air gun, induction coil, and braze by heating. When using other heating methods, pay attention to controlling the temperature and time to prevent damage to the honeycomb itself; Step 5: After brazing, clean the brazing seam to remove residual brazing material and flux. Beneficial Effects

[0009] Compared with the prior art, the present invention has the following beneficial technical effects: The technical solution adopted by the present invention is to utilize the melting reduction effect of Mg, Cu, Zn, Sn, Ge, and Si elements to prepare a low-melting-point solder that can be used to repair alloy honeycombs. Compared with the traditional glue pouring repair method, this method simultaneously ensures the strength and lightness of the repaired honeycomb, filling the gap in aircraft alloy honeycomb repair. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 A schematic diagram of cleaning a damaged area and making a patch in an embodiment; Figure 2 A schematic diagram of an assembly patch and a filling solder of an embodiment; Figure 3 It is a special welding tool for the embodiment. DETAILED DESCRIPTION

[0011] The following is combined with Figure 1-3 The present invention is described in detail, but the protection scope of the present invention is not limited by the accompanying drawings. Example

[0012] A method for preparing a low melting point solder for repairing aluminum alloy honeycomb damage comprises the following steps: Step 1: Prepare solder, the composition is Mg: 7.8%, Cu: 6.3%, Zn: 33.5%, Sn: 2.5%, Ge: 4.25%, Si: 6.25%, and the balance is Al. Weigh various high-purity raw materials according to the above mass percentages, and the purity of various high-purity raw materials is not less than 99.99%; Step 2: Mixing the first part of the Al raw material with the Ge raw material to prepare an Al-Ge compound, and mixing the second part of the Al raw material with the Si raw material to prepare an Al-Si compound; Step 3: uniformly mixing the third part of Al raw material, Mg raw material, Cu raw material, Zn raw material, Sn raw material, Al-Ge compound and Al-Si compound, heating and melting them in an arc furnace under an argon protective atmosphere at a melting temperature of 650° C. for 5 minutes to obtain a bulk alloy; Step 4: The bulk alloy is made into an amorphous sheet. The preparation method of the amorphous sheet is a single-roller rapid cooling method. The thickness of the amorphous sheet is 50 μm.

[0013] The application method of the low melting point solder for repairing the aluminum alloy honeycomb damage comprises the following steps: Step 1: Use a cutting machine to clean 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. Step 2: Clean, polish, and pickle the repaired area and patch to remove oil and oxide film on the surface of the material; Step 3: Install the patch on the area to be repaired, carefully adjust the position, and apply solder paste or put solder foil in the gap between the patch and the original honeycomb. Figure 2 As shown; Step 4: Use this solder to conduct a brazing test on the aluminum foil, use a special repair tool, select a heating head width of 5mm, a temperature of 475℃, and a welding time of 45s; Step 5: After brazing, clean the brazing seam to remove residual brazing material and flux.

[0014] After welding, the specimens were subjected to tensile tests, and all specimens broke at the parent material, indicating that the welding quality was good and the weld strength was higher than that of the parent material. Example

[0015] A method for preparing a low melting point solder for repairing aluminum alloy honeycomb damage comprises the following steps: Step 1: Prepare solder, the composition is Mg: 7.8%, Cu: 6.3%, Zn: 33.5%, Sn: 2.5%, Ge: 4.25%, Si: 6.25%, and the balance is Al. Weigh various high-purity raw materials according to the above mass percentages, and the purity of various high-purity raw materials is not less than 99.99%; Step 2: Mixing the first part of the Al raw material with the Ge raw material to prepare an Al-Ge compound, and mixing the second part of the Al raw material with the Si raw material to prepare an Al-Si compound; Step 3: uniformly mixing the third part of Al raw material, Mg raw material, Cu raw material, Zn raw material, Sn raw material, Al-Ge compound and Al-Si compound, heating and melting them in an arc furnace under an argon protective atmosphere at a melting temperature of 650° C. for 5 minutes to obtain a bulk alloy; Step 4: The bulk alloy is made into an amorphous sheet. The preparation method of the amorphous sheet is a single-roller rapid cooling method. The thickness of the amorphous sheet is 50 μm.

[0016] The application method of the low melting point solder for repairing the aluminum alloy honeycomb damage comprises the following steps: Step 1: Use a cutting machine to clean the area to be repaired and make a welding test block: the size of the aluminum honeycomb test block is 100 x 100 mm, the size of the area to be repaired is 50 x 50 mm, and the honeycomb size is 12.8 mm; the size of the patch block is 55 x 55 mm, and the honeycomb size is consistent with the material to be repaired; Step 2: Clean, polish, and pickle the repaired area and patch to remove oil and oxide film on the surface of the material; Step 3: Assemble the patch block and the honeycomb to be repaired, adjust the position and put the solder foil into the gap between the two test blocks; Step 4: Use Figure 3 The special repair tool in the brazing process was selected with a heating head width of 5 mm, a temperature of 475°C, and a welding time of 45 seconds, and the honeycomb welds were brazed in sequence; Step 5: After brazing, clean the brazing seam to remove residual brazing material and flux.

[0017] After welding was completed, the weld quality was tested and no cracks were found in any welds, indicating good welding quality.

Claims

1. A method for preparing a low melting point solder for repairing aluminum alloy honeycomb damage, characterized in that: The following steps are involved: Step 1: The chemical composition mass percentages of the low melting point solder are: Mg: 5-12%, Cu: 5-13%, Zn: 10-40%, Sn: 1.5-4.5%, Ge: 2.0-6.0%, Si: 4.5-12.5%, and the balance is Al; Weigh various high-purity raw materials according to the mass percentage of the chemical composition of the solder, and the purity of the various high-purity raw materials is not less than 99.99%; Step 2: Divide the Al raw material into three parts, namely, the first part, the second part and the third part; wherein the first part is combined with Ge to form an Al-Ge compound, and the second part is combined with Si to form an Al-Si compound; Step 3: Evenly mix the third part of Al raw material, Mg raw material, Cu raw material, Zn raw material, Sn raw material, Al-Ge compound and Al-Si compound, heat and melt them in an arc furnace under an argon protective atmosphere to obtain a block alloy, i.e. the above-mentioned low-melting-point repair solder.

2. The method for preparing a low melting point solder for repairing aluminum alloy honeycomb damage according to claim 1, characterized in that: In step 2, the mass ratio of the first part of Al raw material, the second part of Al raw material and the third part of Al raw material depends on the specific composition of the solder.

3. The method for preparing a low melting point solder for repairing aluminum alloy honeycomb damage according to claim 1, characterized in that: In step three, the melting temperature of the electric arc furnace is 700° C. and the melting time is 5 min-10 min, so as to facilitate the full diffusion and fusion of the elements and avoid the loss of the elements.

4. The method for preparing a low melting point solder for repairing aluminum alloy honeycomb damage according to claim 1, characterized in that: In step three, the bulk alloy is made into an amorphous sheet. The preparation method of the amorphous sheet is a single-roller rapid cooling method. The thickness of the amorphous sheet is 50 μm.

5. The method for preparing a low melting point solder for repairing aluminum alloy honeycomb damage according to claim 1, characterized in that: The following steps are involved: Step 1: Use a cutting machine to clean the area to be repaired and process the corresponding repair patch, where the patch size should be larger than the size of the area to be repaired, where L is 0.3-0.5 times the honeycomb radius; Step 2: Clean, polish, and pickle the repaired area and patch to remove oil and oxide film on the surface of the material; Step 3: Install the patch on the area to be repaired, carefully adjust the position, and apply solder paste or put solder foil into the gap between the patch and the original honeycomb; Step 4: Use special repair tools or flame, hot air gun, induction coil, and braze by heating. When using other heating methods, pay attention to controlling the temperature and time to prevent damage to the honeycomb itself; Step 5: After brazing, clean the brazing seam to remove residual brazing material and flux.

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