Brazing and heat treatment manufacturing method for 6061 aluminum alloy flat plate slot antenna

Abstract

The invention belongs to the technical field of flat plate slot antenna manufacturing, and discloses a 6061 aluminum alloy flat plate slot antenna brazing and heat treatment manufacturing method. The method comprises the steps of preparing, cleaning, assembling, vacuum brazing, solution treatment and aging treatment, Al-Si-Ge series brazing filler metal is selected, and a vacuum uniform temperature field regulation and control process curve is researched and developed to achieve vacuum brazing of the 6061 aluminum alloy antenna. The problems that in an existing brazing system, the melting point of brazing filler metal is not matched with the melting point of base metal in temperature and the brazing filler metal is not melted synchronously and spread continuously due to uneven temperature distribution of a large-size antenna are solved, and it is guaranteed that a weld joint is continuous and compact. A multiphase flow cooling field homogenization regulation and control tool is used for establishing an antenna full-space cooling field, uniform and rapid cooling of the 6061 aluminum alloy antenna is achieved by regulating and controlling the air fog speed and the coverage area, the problem of solid solution deformation of a thin-wall structural part is solved, and it is guaranteed that the size of the antenna is stable, and the strength of the antenna is improved; and a specification is provided for engineering manufacturing of the high-precision 6061 aluminum alloy flat plate slot antenna.

Description

Technical Field

[0001] This invention relates to the field of flat panel slotted antenna manufacturing technology, and in particular to a brazing and heat treatment manufacturing method for a 6061 aluminum alloy flat panel slotted antenna. Background Technology

[0002] The planar slot antenna is a typical planar array antenna, composed of multiple compactly connected layers such as a feed layer, coupling layer, and power layer. It boasts advantages such as high radiation efficiency, strong directivity, compact structure, light weight, high gain, and low sidelobes, and is widely used in ground-based, navigation, and weather radar applications. The antenna structure features multiple layers, cavities, and thin walls; the complexity and high precision required make vacuum aluminum brazing the preferred forming method.

[0003] The following problems exist in the engineering manufacturing of 6061 aluminum alloy flat panel antennas: (1) The commonly used Al-Si-Mg brazing filler metals in GB / T 13815 "Aluminum-based Brazing Filler Metals" include BAl88Si(Mg) and BAl89SiMg(Bi), with melting points in the range of 579℃ to 591℃. The melting point of 6061 aluminum alloy is in the range of 582℃ to 652℃. The melting points of the two are close, the brazing window is narrow, and the brazing temperature and furnace uniformity are difficult to control. During the welding process, welding defects such as base metal erosion are easy to occur, the weld joint softens severely, the strength coefficient decreases, and the welding quality cannot be guaranteed; if the welding temperature is reduced, the brazing filler metal will not melt completely, which will easily lead to false welding and seriously affect the joint performance; the melting temperature of Al-Si-Ge brazing filler metal can be reduced to 519℃, but this brazing filler metal is rarely used in the vacuum brazing of 6061 aluminum alloy flat panel crack antennas. The antenna has a large external size and many layers. During the brazing process, uneven furnace temperature and uneven workpiece temperature distribution can easily cause asynchronous melting and spreading of the brazing filler metal, such as overflow of the overheated layer and incomplete spreading of the underheated layer. It is necessary to further develop process curves and welding parameters to control the temperature uniformity of the antenna and ensure continuous and dense welds. (2) When heat treating 6061 aluminum alloy, it is necessary to cool it to room temperature at a sufficient cooling rate to avoid early decomposition of the solid solution, which would affect the mechanical properties of the alloy after aging. The conventional solid solution methods are water cooling and air cooling. The antenna is large in size, thin in wall, has many layers and hollow cavity. Water cooling can easily lead to large-area deformation, which will seriously damage the accuracy of the radiation hole and reduce the electrical performance. Air cooling can easily lead to uneven cooling rates at the antenna edge and inside, and uneven cooling rates between the top and bottom parts, which will eventually lead to uneven deformation of the thin-walled antenna. In addition, if the air cooling rate is too slow, the antenna will have low strength after heat treatment, that is, it is difficult to control the antenna deformation while improving the strength.

[0004] These challenges result in a low pass rate in antenna engineering manufacturing. Substandard products cannot be repaired and must be scrapped. Due to the high dimensional precision of the parts and the difficulty of machining, scrapping them incurs significant cost losses. Summary of the Invention

[0005] The purpose of this invention is to provide a brazing and heat treatment manufacturing method for a 6061 aluminum alloy planar cracked antenna. This method utilizes Al-Si-Ge brazing filler metal and develops a vacuum temperature field control process curve to achieve vacuum brazing of the 6061 aluminum alloy antenna. It aims to solve the problems of temperature mismatch between the melting point of the brazing filler metal and the melting point of the base material in existing brazing systems, as well as the problems of uneven temperature distribution in large-size antennas causing asynchronous melting and discontinuous spreading of the brazing filler metal, ensuring a continuous and dense weld. A multiphase flow cooling field homogenization control fixture is used to establish a full-space cooling field for the antenna. By controlling the wind speed and coverage area, uniform and rapid cooling of the 6061 aluminum alloy antenna is achieved, solving the problem of solid solution deformation in thin-walled structural components, ensuring antenna dimensional stability and improved strength, and providing a standard for the engineering manufacturing of high-precision 6061 aluminum alloy planar cracked antennas.

[0006] To achieve the above objectives, the present invention provides a method for brazing and heat treatment of a 6061 aluminum alloy flat panel crack antenna, comprising the following steps: Step 1: Preparation: Select Al-Si-Ge brazing filler metal with a thickness of 0.05mm~0.08mm and a width of 100mm~150mm. Use laser processing equipment to process the brazing filler metal into a single piece along the welding surface. Step 2: Cleaning: Use chemical cleaning to remove surface oxides from each layer of the 6061 aluminum alloy flat panel crack antenna components and brazing filler metal. After cleaning, dry the surface moisture in an oven at 100℃~120℃. Step 3: Assembly: Assemble the brazing filler metal onto the welding surface, and use tooling to press the upper layer of the 6061 aluminum alloy flat panel slotted antenna to ensure that the welding gap is less than 0.05mm; Step 4: Vacuum Brazing: Place the assembled 6061 aluminum alloy flat panel slotted antenna components, brazing filler metal, and welding fixtures into a vacuum brazing furnace. Temperature-measuring thermocouples are inserted into each layer of the 6061 aluminum alloy flat panel slotted antenna components to display the temperature of each layer in real time. Heating is performed using a "vacuum degree-temperature gradient-temperature uniformity" temperature control curve. The temperature control curve is set with four heating stages: cold low vacuum stage, preheating stage, temperature uniformity stage, and final temperature stage. The "vacuum degree-temperature gradient-temperature uniformity" temperature control curve includes a vacuum degree temperature control curve, a heating rate temperature control curve, and a temperature uniformity temperature control curve. Step 5: Solution treatment: The welded 6061 aluminum alloy flat plate cracked antenna is placed horizontally into a well-type heating furnace for solution treatment. The heating temperature is 520±10℃. After the heat preservation is completed, the 6061 aluminum alloy flat plate cracked antenna is quickly transferred out of the well-type heating furnace and cooled using a solution cooling fixture. Step 6: Aging treatment: Place the solution-treated 6061 aluminum alloy flat cracked antenna flat in an oven for aging treatment at a temperature of 175±5℃. After the aging process, cool it to room temperature.

[0007] Furthermore, the Al-Si-Ge solder selected in step 1 has a width of 100 mm and a thickness of 0.08 mm.

[0008] Furthermore, the chemical cleaning method in step 2 uses a chemical solution containing 10% NaOH solution and 10% HNO3 solution, and the temperature inside the oven is 120℃.

[0009] Furthermore, step 4 involves heating using a temperature control curve based on "vacuum degree - temperature gradient - temperature uniformity," and includes the following operations: When the vacuum level is below 1.0 × 10 -3 When Pa is reached, subsequent heating is started. The temperature readings of all thermocouples of the 6061 aluminum alloy flat plate crack antenna are 540±1℃. The heating program is then turned off. After heating is completed, the antenna is removed from the vacuum brazing furnace when it cools to below 100℃. The welding fixture can be removed after cooling to room temperature.

[0010] Furthermore, the solution cooling fixture in step 5 includes a frame, a fan atomizer, and an antenna hanger; The frame includes a support base, an outer frame, and nine fan mounting plates. The support base, outer frame, and fan mounting plates are all made of stainless steel profiles welded together to ensure strength, and a hollow structure is used to ensure heat dissipation efficiency. In addition to installing fan mounting plates at the eight vertices of the outer frame, an extra set of fan mounting plates is added to the bottom surface; The fan atomizer includes a fan, water pipes, and atomizing nozzles. The fan has an adjustable angle and blows water mist onto the 6061 aluminum alloy flat panel crack antenna. The antenna hanger includes a hook and a fixture base plate. The hook can rotate horizontally, and the fixture base plate has a hollow design.

[0011] Furthermore, in step 5, the heating temperature is increased to 510°C in 1 hour, and then kept at that temperature for 1 hour.

[0012] Furthermore, in step 6, the aging temperature is increased to 175°C in 1 hour, followed by holding at that temperature for 8 hours.

[0013] Beneficial effects: The present invention provides a brazing and heat treatment manufacturing method for a 6061 aluminum alloy flat plate crack antenna, which has the following beneficial effects: (1) The present invention develops a multi-field temperature control process curve of "vacuum degree-temperature gradient-temperature uniformity" for Al-Si-Ge brazing filler metal for multi-layer large 6061 aluminum alloy antennas. Through multiple temperature gradients, the vacuum degree in the furnace and the temperature uniformity of multi-layer parts are guaranteed, solving the problems of mismatch between the melting point of the brazing filler metal and the melting point of the base material, asynchronous melting of the brazing filler metal and uneven spreading during the welding process. (2) The present invention provides a cooling fixture to address the problems of uneven deformation and insufficient strength of thin-walled large antennas under solid solution cooling. Through the wind-mist two-phase flow cooling medium and uniform cooling field control fixture, the antenna can be rapidly and uniformly cooled at various thin and thick positions, solving the problems of uneven deformation and insufficient strength of large-size thin-walled structures. Attached Figure Description

[0014] Figure 1 This invention relates to a process flow diagram of the brazing and heat treatment manufacturing method for a 6061 aluminum alloy flat panel crack antenna. Figure 2 This is a schematic diagram of the heating curve involved in an embodiment of the present invention; Figure 3 This is a schematic diagram of the solution cooling fixture involved in an embodiment of the present invention; Figure 4 This is a schematic diagram of the 6061 aluminum alloy flat panel slot antenna prepared according to an embodiment of the present invention; Figure 5 This is a schematic diagram of laser cutting of antenna solder according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the antenna vacuum brazing temperature curve according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the external weld after vacuum brazing and solution aging heat treatment of the antenna according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the internal weld after vacuum brazing and solution aging heat treatment according to an embodiment of the present invention. Detailed Implementation

[0015] The preferred mechanisms and implementation methods of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0016] like Figures 1 to 8 As shown in the figure, the present invention discloses a technical solution for a method of brazing and heat treatment manufacturing of a 6061 aluminum alloy flat panel crack antenna. Figure 1 This invention relates to a process flow diagram of the brazing and heat treatment manufacturing method for a 6061 aluminum alloy flat panel crack antenna. Figure 2 This is a schematic diagram of the heating curve involved in an embodiment of the present invention; Figure 3This is a schematic diagram of the solution cooling fixture involved in an embodiment of the present invention; Figure 4 This is a schematic diagram of the 6061 aluminum alloy flat panel slot antenna prepared according to an embodiment of the present invention; Figure 5 This is a schematic diagram of laser cutting of antenna solder according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the antenna vacuum brazing temperature curve according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the external weld after vacuum brazing and solution aging heat treatment of the antenna according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the internal weld after vacuum brazing and solution aging heat treatment according to an embodiment of the present invention.

[0017] Example 1: Preparation Figure 1 The 6061 aluminum alloy planar slot antenna shown has dimensions of 700mm × 700mm (length × width), a cavity depth of 5mm, and a wall thickness of 1mm. It consists of three layers: a feed layer, a coupling layer, and a power layer. Figure 4 As shown.

[0018] This invention provides a method for brazing and heat treatment of a 6061 aluminum alloy flat panel crack antenna, comprising the following steps: Step 1: Preparation: Select Al-Si-Ge solder with a width of 100mm and a thickness of 0.08mm, cut it to a length of 700mm, and use laser processing equipment to integrally shape the solder along the welding surface; for example... Figure 5 As shown.

[0019] Step 2: Cleaning: Chemical cleaning is used to remove surface oxides from the various layers of components and brazing filler metal of the 6061 aluminum alloy flat panel slotted antenna. After cleaning, the surface moisture is dried in a 120℃ oven. The chemical solution used in the chemical cleaning method includes 10% NaOH solution and 10% HNO3 solution.

[0020] Step 3: Assembly: Assemble the brazing filler metal onto the welded surfaces of each layer. To ensure the brazing filler metal spreads and fills the gaps, use a tooling to press the 6061 aluminum alloy flat panel crack antenna to ensure that the weld gap is less than 0.05mm.

[0021] Step 4: Vacuum Brazing: Place the assembled 6061 aluminum alloy flat panel slotted antenna components, brazing filler metal, and welding fixtures into a vacuum brazing furnace. Temperature-measuring thermocouples are inserted into each layer of the 6061 aluminum alloy flat panel slotted antenna components to display the temperature of each layer in real time. Heating is performed using a "vacuum degree-temperature gradient-temperature uniformity" temperature control curve. The temperature control curve is set to four stages (cold vacuum stage and three gradient heating stages). The "vacuum degree-temperature gradient-temperature uniformity" temperature control curve includes a vacuum degree temperature control curve, a heating rate temperature control curve, and a uniformity temperature control curve. See the temperature curves below. Figure 6The vacuum brazing parameters of this invention are shown in Table 1, including gradient temperature, heating rate, temperature uniformity, and vacuum degree. The heating curves are shown in Table 1. Figure 2 ;

[0022] .

[0023] This embodiment selects a vacuum level below 1.0 × 10⁻⁶. -3 When Pa is reached, subsequent heating is initiated. The temperature readings of all thermocouples on the 6061 aluminum alloy flat-plate slotted antenna are 540±1℃. The heating program is then shut off. After heating, the antenna is cooled to below 100℃ within the vacuum brazing furnace and removed. Once cooled to room temperature, the welding fixture can be removed. The temperature control curve is shown below. Figure 6 The vacuum brazing welding parameters are shown in Table 2.

[0024] .

[0025] Step 5: Solution treatment: After the 6061 aluminum alloy flat cracked antenna is brazed, it is placed horizontally into a well-type heating furnace for heating and heat preservation. The heating and heat preservation operation is to raise the temperature to 510℃ for 1 hour, and then keep it at that temperature for 1 hour. After the heat preservation is completed, the 6061 aluminum alloy flat cracked antenna is quickly transferred out of the well-type furnace and solution treatment is performed using a solution cooling fixture.

[0026] The solution cooling fixture in step 5 includes a frame, a fan atomizer, and an antenna hanger; The frame includes a support base, an outer frame, and nine fan mounting plates. The support base, outer frame, and fan mounting plates are all made of stainless steel profiles welded together to ensure strength, and a hollow structure is used to ensure heat dissipation efficiency. In addition to installing fan mounting plates at the eight vertices of the outer frame, an extra set of fan mounting plates is added to the bottom surface; The fan atomizer includes a fan, water pipes, and atomizing nozzles. The fan has an adjustable angle and blows water mist onto the 6061 aluminum alloy flat panel crack antenna. The antenna hanger includes a hook and a tooling base plate. The hanger can rotate horizontally, and the tooling base plate has a hollow design.

[0027] In this embodiment, thermal simulation technology is used to adjust the angle and speed of the fan in the solution cooling fixture to achieve uniform cooling of all layers and positions of the antenna. The fan speed is set to 10 m / s, the cooling time is 90 s, and then the fan and spray are turned off, allowing air cooling to reach room temperature.

[0028] Step 6: Aging Treatment: The solution-treated 6061 aluminum alloy flat cracked antenna is placed flat in an oven for aging treatment. The heating and holding process involves raising the temperature to 175℃ for 1 hour, followed by holding at that temperature for 8 hours. After the holding period, the antenna is cooled to room temperature in the furnace. The completed external and internal welds are as follows: Figure 7 , 8 As shown.

[0029] This invention provides a method for brazing and heat treatment manufacturing of a 6061 aluminum alloy planar cracked antenna. It utilizes Al-Si-Ge brazing filler metal and develops a vacuum temperature field control process curve to achieve vacuum brazing of the 6061 aluminum alloy antenna. This solves the problems of temperature mismatch between the melting point of the brazing filler metal and the melting point of the base material in existing brazing systems, as well as the problems of asynchronous melting and discontinuous spreading of the brazing filler metal caused by uneven temperature distribution in large-size antennas, ensuring a continuous and dense weld. A multiphase flow cooling field homogenization control fixture is used to establish a full-space cooling field for the antenna. By controlling the wind speed and coverage area, uniform and rapid cooling of the 6061 aluminum alloy antenna is achieved, solving the problem of solid solution deformation in thin-walled structural components, ensuring antenna dimensional stability and improved strength, and providing a standard for the engineering manufacturing of high-precision 6061 aluminum alloy planar cracked antennas.

[0030] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. However, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for manufacturing a 6061 aluminum alloy flat panel crack antenna by brazing and heat treatment, characterized in that, Includes the following steps: Step 1: Preparation: Select Al-Si-Ge brazing filler metal with a thickness of 0.05mm~0.08mm and a width of 100mm~150mm. Use laser processing equipment to process the brazing filler metal into a single piece along the welding surface. Step 2: Cleaning: Use chemical cleaning to remove surface oxides from each layer of the 6061 aluminum alloy flat panel crack antenna components and brazing filler metal. After cleaning, dry the surface moisture in an oven at 100℃~120℃. Step 3: Assembly: Assemble the brazing filler metal onto the welding surface, and use tooling to press the upper layer of the 6061 aluminum alloy flat panel slotted antenna to ensure that the welding gap is less than 0.05mm; Step 4: Vacuum Brazing: Place the assembled 6061 aluminum alloy flat panel slotted antenna components, brazing filler metal, and welding fixtures into a vacuum brazing furnace. Temperature-measuring thermocouples are inserted into each layer of the 6061 aluminum alloy flat panel slotted antenna components to display the temperature of each layer in real time. Heating is performed using a "vacuum degree-temperature gradient-temperature uniformity" temperature control curve. The temperature control curve is set with four heating stages: cold low vacuum stage, preheating stage, temperature uniformity stage, and final temperature stage. The "vacuum degree-temperature gradient-temperature uniformity" temperature control curve includes a vacuum degree temperature control curve, a heating rate temperature control curve, and a temperature uniformity temperature control curve. Step 5: Solution treatment: The welded 6061 aluminum alloy flat plate cracked antenna is placed horizontally into a well-type heating furnace for solution treatment. The heating temperature is 520±10℃. After the heat preservation is completed, the 6061 aluminum alloy flat plate cracked antenna is quickly transferred out of the well-type heating furnace and cooled using a solution cooling fixture. Step 6: Aging treatment: Place the solution-treated 6061 aluminum alloy flat cracked antenna flat in an oven for aging treatment at a temperature of 175±5℃. After the aging process, cool it to room temperature.

2. The method for manufacturing a 6061 aluminum alloy flat panel crack antenna by brazing and heat treatment according to claim 1, characterized in that, The Al-Si-Ge solder selected in step 1 has a width of 100 mm and a thickness of 0.08 mm.

3. The method for manufacturing a 6061 aluminum alloy flat panel crack antenna by brazing and heat treatment according to claim 1, characterized in that, The chemical cleaning method in step 2 uses a chemical solution containing 10% NaOH solution and 10% HNO3 solution, and the temperature inside the oven is 120℃.

4. The method for manufacturing a 6061 aluminum alloy flat panel crack antenna by brazing and heat treatment according to claim 1, characterized in that, Step 4 involves heating using a temperature control curve based on "vacuum degree - temperature gradient - temperature uniformity," and includes the following operations: When the vacuum degree is below 1.0×10 -3 When Pa is reached, subsequent heating is started. The temperature readings of all thermocouples of the 6061 aluminum alloy flat plate crack antenna are 540±1℃. The heating program is then turned off. After heating is completed, the antenna is removed from the vacuum brazing furnace when it cools to below 100℃. The welding fixture can be removed after cooling to room temperature.

5. The method for manufacturing a 6061 aluminum alloy flat panel crack antenna by brazing and heat treatment according to claim 1, characterized in that, The solution cooling fixture in step 5 includes a frame, a fan atomizer, and an antenna hanger; The frame includes a support base, an outer frame, and nine sets of fan mounting plates. The support base, outer frame, and fan mounting plates are all made of stainless steel profiles welded together to ensure strength, and a hollow structure is used to ensure heat dissipation efficiency. In addition to installing fan mounting plates at the eight vertices of the outer frame, an extra set of fan mounting plates is added to the bottom surface; The fan atomizer includes a fan, a water pipe, and an atomizing nozzle. The fan is adjustable in angle and blows water mist toward the 6061 aluminum alloy flat panel crack antenna. The antenna hanger includes a hook and a fixture base plate. The hook can rotate horizontally, and the fixture base plate has a hollow design.

6. The method for manufacturing a 6061 aluminum alloy flat panel crack antenna by brazing and heat treatment according to claim 1, characterized in that, In step 5, the heating temperature is increased to 510℃ in 1 hour, and then kept at that temperature for 1 hour.

7. The method for manufacturing a 6061 aluminum alloy flat panel crack antenna by brazing and heat treatment according to claim 1, characterized in that, In step 6, the aging temperature is increased to 175°C in 1 hour, and then kept at that temperature for 8 hours.

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