Aluminum alloy U-shaped tube type radiator processing method
Patent Information
- Application Number
- CN202611052755.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-15
- Publication Date
- 2026-09-25
AI Technical Summary
[0005]本发明旨在提供一种铝合金U型列管式散热器加工方法，解决铝合金U型列管难钎焊、效率低、难于一体钎焊的难题，提高铝合金U型列管式散热器钎焊质量和焊接合格率
[0017]本发明公开了一种铝合金U型列管式散热器加工方法，根据铝合金U型列管式散热器芯子组件中不同的升温特性利用特定钎料+钎剂进行惰性气保护钎焊的方法将铝合金U型列管分别与折流板（多层）、芯子端板（1层）进行钎焊。首先将折流板（采用双面钎料复合板）、芯子端板、定位杆、定距套、U型散热管进行除油、碱+酸清洗，再进行烘干；其次将各钎焊处涂抹钎剂，并进行装配，然后根据待钎焊零件（主要是芯子端板和折流板）升温特性不同，在芯子端板处涂覆与折流板不同的钎料，因芯子端板厚，升温较折流板处慢，加上惰性气保护钎焊易因温度因素产生熔蚀，避免厚度较薄的折流板处因温度过高产生熔蚀；最后，在惰性气保护钎焊炉中进行钎焊，并充入特定流量的惰性气进行保护。
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Figure CN122807507A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a processing method for an aluminum alloy U-shaped tube radiator, used in a series of oil-fired radiators, and belongs to the field of heat exchanger processing technology. Background Technology
[0002] Heat exchangers utilize the flow of heat transfer media inside and outside tube bundles to achieve heat transfer, and are developing towards lighter weight and faster thermal conductivity. Capillary tubes of different heat dissipation tube specifications made of stainless steel, high-temperature alloys, and even titanium alloys can be well joined using vacuum brazing technology. Although aluminum alloy sheets can also be vacuum brazed, the vacuum brazing of aluminum alloy capillary tubes still suffers from high costs and low yield rates. With the increasing demands for production capacity and cost reduction, the current situation of long lead times and high costs in vacuum brazing aluminum tubes urgently needs to be addressed.
[0003] The aluminum alloy U-shaped tube radiator has a complex tube bundle structure, consisting of approximately 200 U-shaped heat dissipation tubes and about 400 brazed joints. Furthermore, to maximize the heat exchange area and improve heat exchange efficiency within a limited volume, the distance between the heat dissipation tubes must be strictly controlled (no more than 0.6mm). The brazing process is inherently difficult, and the large number of tubes, the 12mm plate thickness (8mm brazing depth), and the structural limitations of the core end plate leading to insufficient filler metal all contribute to the high technical requirements for product manufacturing.
[0004] For aluminum alloy U-shaped tube-and-shell radiators, there are two traditional methods for connecting the U-shaped heat pipes to the core end plate: riveting and vacuum brazing. Riveting is labor-intensive, inefficient, results in low connection strength, and is not heat-resistant. Vacuum brazing is time-consuming, requires stringent conditions, and is complex to operate. Summary of the Invention
[0005] The present invention aims to provide a processing method for aluminum alloy U-shaped tube radiators, which solves the problems of difficult brazing, low efficiency and difficulty in integral brazing of aluminum alloy U-shaped tubes, and improves the brazing quality and welding qualification rate of aluminum alloy U-shaped tube radiators.
[0006] The main idea of this invention is to use inert gas-protected brazing to weld the internal structure of the radiator, and to use different brazing filler metals and appropriate fluxes to target the heating conditions of different components (baffles and core end plates) in the aluminum alloy U-shaped tube radiator core assembly. By using a ring with a non-wetting brazing filler metal to help increase the amount of brazing filler metal used between the core end plate and the U-shaped heat pipe, the brazing of the aluminum alloy U-shaped tube radiator core assembly can be completed in one step.
[0007] To achieve the objectives of this invention, the following technical solution is adopted: A method for processing an aluminum alloy U-shaped tube-type radiator includes: Step 1: Parts processing. Complete the processing of parts including baffle plate, core end plate, positioning rod, spacer sleeve and U-shaped heat dissipation pipe. The baffle plate is a double-sided brazing composite plate. Ensure that the dimensions after processing are such that there is a brazing gap of no more than the set value between the core end plate and the U-shaped heat dissipation pipe, and between the baffle plate and the U-shaped heat dissipation pipe during subsequent assembly. Step 2: Parts cleaning. The parts to be brazed are degreased and treated with a combination of alkaline washing and acid washing. Then they are dried. Step 3: Assembly. First, assemble the baffle plate, core end plate, positioning rod and spacer set to form a frame. Then, install the free end of each U-shaped heat dissipation tube onto the core end plate, starting from the inside of the core end plate and working outwards. Step 4: Solder coating. A surface-coated ring is attached to the end face of the core end plate away from the U-shaped heat pipe. The coating layer of the ring should not wet the solder used for brazing the core end plate and the U-shaped heat pipe. This creates a solder filling area in the inner ring hole area of the ring, while the ring itself forms a barrier to ensure the amount of solder used between the core end plate and the U-shaped heat pipe. The liquidus line of the solder used for brazing the core end plate and the U-shaped heat pipe is lower than the liquidus line of the solder composite on the surface of the baffle plate. Step 5: Brazing. A non-vacuum brazing furnace is used to heat the material rapidly to a temperature higher than the brazing temperature, and then the temperature is cooled down to the brazing temperature plateau to quickly complete the brazing process and obtain the aluminum alloy U-shaped tube-type radiator core assembly. Step 6: Heat treatment. First, the aluminum alloy U-shaped tube radiator core assembly is subjected to solution treatment, followed by aging treatment. Step 7: Assembly processing. First, install the aluminum alloy U-shaped tube radiator core assembly into the cylinder. Then, assemble the fuel and lubricating oil inlet and outlet end caps and the lubricating oil inlet and outlet assembly. Next, use laser welding to weld the cylinder, the aluminum alloy U-shaped tube radiator core assembly, and the fuel and lubricating oil inlet and outlet end caps.
[0008] As one possible approach: the first step also includes punching the surface of the U-shaped heat pipe.
[0009] As one possible approach: In the second step, firstly, an alkaline wash is performed using a solution of NaOH + NaCO3, followed by neutralization with acid wash using HNO3.
[0010] As one possible solution: In the second step, during the degreasing, alkaline washing, and acid washing processes, no degreasing agent, alkaline washing solution, or acid washing solution should remain inside the U-shaped part of the U-shaped heat sink.
[0011] As one possible solution: In the third step, the lower end of the positioning rod is connected to the core end plate, the spacer sleeve is fitted onto the outside of the positioning rod, and the baffle plate is inserted into the positioning rod and contacts the end face of the spacer sleeve.
[0012] As one possible solution: In the third step, the free end of the U-shaped heat sink is inserted into the assembly hole of the core end plate and then extends a certain distance out of the hole.
[0013] As one solution: In the third step, flux is applied to the brazing joint between the baffle plate and the U-shaped heat sink (the flux is applied to the baffle plate when forming the frame, and then applied after assembly). In the third step, flux is first applied to the brazing joint between the core end plate and the U-shaped heat sink. In the fourth step, the solder and flux are mixed and then applied to the brazing joint between the core end plate and the U-shaped heat sink. The first application of flux is to enhance the flux film breaking effect. After the first flux application is completed, the core end plate and the U-shaped heat sink are assembled, and then the mixture of flux and solder is applied to the brazing joint.
[0014] As one possible approach: In the fourth step, the brazing filler metal used for brazing the core end plate and the U-shaped heat sink is the same series of brazing filler metal as the brazing filler metal composite on the surface of the baffle plate, and the liquidus line of the brazing filler metal is reduced by increasing or decreasing one or more of its elements.
[0015] As one possible approach: In the fifth step, before heating, the non-vacuum brazing furnace is first filled with inert gas to purge the air inside the furnace, and then the inert gas is extracted. This process is repeated several times before heating and filling with inert gas to perform brazing.
[0016] As one possible solution: In the sixth step, after aging treatment, the core end plate is subjected to hardness testing to determine whether the strength meets the requirements.
[0017] This invention discloses a processing method for an aluminum alloy U-shaped tube-type radiator. Based on the different heating characteristics of the core components of the aluminum alloy U-shaped tube-type radiator, a method using specific brazing filler metal and flux for inert gas-protected brazing is employed to braze the aluminum alloy U-shaped tubes to a multi-layer baffle plate and a single-layer core end plate. First, the baffle plate (using a double-sided brazing filler metal composite plate), core end plate, positioning rod, spacer sleeve, and U-shaped heat dissipation tubes are degreased, cleaned with alkali and acid, and then dried. Next, flux is applied to each brazing joint, and the components are assembled. Then, based on the different heating characteristics of the parts to be brazed (mainly the core end plate and baffle plate), a different brazing filler metal is applied to the core end plate than to the baffle plate. Because the core end plate is thicker, its heating is slower than that of the baffle plate. Furthermore, inert gas-protected brazing is prone to erosion due to temperature factors, thus preventing erosion of the thinner baffle plate due to excessive temperature. Finally, brazing is performed in an inert gas-protected brazing furnace, with a specific flow rate of inert gas used for protection.
[0018] This invention solves the difficult problem of brazing aluminum alloy U-shaped tube radiators, especially the challenge of integral brazing, and provides a reference for other integrally brazed products. The processing method of this invention improves brazing quality and production efficiency, and broadens the processing methods and application areas of radiators / heat exchangers.
[0019] Compared with the prior art, the present invention has the following characteristics: (1) Low cost. Vacuum brazing has a service life of no less than 10 hours. The processing method of the present invention can be completed in just 3 hours, which greatly shortens the processing cycle and reduces time and equipment usage costs. (2) Adjust the corresponding brazing filler metal according to the different heating characteristics of the components in the aluminum alloy U-shaped tube radiator core assembly, so that the aluminum alloy U-shaped tube radiator core assembly can be brazed in one go, thereby improving the brazing efficiency. (3) By using a ring with a surface coating layer, a brazing filler metal that cannot wet the coating layer is matched to provide sufficient brazing filler metal for the core end plate and the U-shaped heat sink tube. There is no need to reserve a margin on the end face of the core end plate, reducing the amount of machining work before and after brazing. Attached Figure Description
[0020] Figure 1 Assemble the frame for the core assembly of the aluminum alloy U-shaped tube radiator; Figure 2 It is a U-shaped heat dissipation pipe; Figure 3 It is an aluminum alloy U-shaped tube-type radiator core assembly; Figure 4 For oil-fired radiator assembly; In the diagram: 1. Core end plate, 2. Positioning rod, 3. Baffle plate, 4. Spacer sleeve, 5. Cylinder body, 6. Fuel inlet / outlet end cap, 7. Lubricating oil inlet / outlet assembly, 8. Laser weld. Detailed Implementation
[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, it should not be construed that the scope of the subject matter of the present invention is limited to the following embodiments. All modifications, substitutions and alterations made based on ordinary technical knowledge and conventional means in the art without departing from the above-described technical concept of the present invention are included within the scope of the present invention.
[0022] like Figures 1-4 This invention designs a processing method for an aluminum alloy U-shaped tube-type radiator, comprising: Step 1: Parts processing. Complete the processing of each component, including the U-shaped heat pipe forming. The dimensions of each component must ensure that the brazing gap does not exceed the set value. Step 2: Cleaning and degreasing the parts. First, use alkaline cleaning, then acid cleaning. During the alkaline + acid cleaning process, the U-shaped part of the U-shaped heat sink is only degreased. After acid cleaning, it is blown dry and finally dried. Step 3: Assembly, first assemble as follows Figure 1 The frame shown is assembled, and then the U-shaped heat dissipation pipes are installed one by one from the inside to the outside. Bending of the aluminum alloy U-shaped heat dissipation pipes should be avoided; the baffle plate 3 is a double-layer brazing filler plate. Step 4: Solder coating, on Figure 1 A ring-shaped part with a surface coating is attached to the lower end face of the core end plate 1 to form a barrier. The inner area of the ring-shaped part is convenient for filling with solder to ensure the amount of solder between the core end plate 1 and the U-shaped heat sink. The solder is the same series as the solder on the surface of the baffle plate 3, but the liquidus line is lower than the liquidus line of the solder on the surface of the baffle plate 3. Step 5: Brazing. Because the walls of the U-shaped heat sink tubes are relatively thin, they are prone to erosion during nitrogen-protected brazing. Therefore, to solve this problem, a rapid heating method is adopted to raise the overall temperature of the aluminum alloy U-shaped tube heat sink core assembly, and then cool it down to near the brazing temperature plateau to ensure rapid completion of brazing. Step 6: Heat treatment. The brazed aluminum alloy is in an annealed state, and its strength is reduced. In order to ensure the strength, the aluminum alloy U-shaped tube heat sink core assembly is first solution treated and then aged. Step 7: Assembly processing. The aluminum alloy U-shaped tube radiator core assembly is welded to the fuel and lubricating oil inlet and outlet end caps, lubricating oil inlet and outlet assemblies and cylinder. In order to reduce the influence of the outer ring welding on the brazing of the U-shaped heat dissipation tubes in the core assembly, laser welding is used to weld the assembly and complete the pressure test.
[0023] The following section uses the following materials as examples to illustrate the processing method of aluminum alloy U-shaped tube radiators: baffle plate 3 (double-sided brazing composite plate) made of 3A21 material, core end plate 1 made of 6063 material, positioning rod 2 made of 6061 material, spacer sleeve 4 made of 6061 material, U-shaped heat dissipation tube made of 3A21 material, cylinder 5 made of 6063 material, and oil inlet and outlet end caps made of 6063 material.
[0024] This invention utilizes a specific Al-Si brazing filler metal and flux for nitrogen-protected brazing, brazing an aluminum alloy U-shaped heat sink to a baffle plate 3 (4 layers) and a core end plate 1 (1 layer). First, the baffle plate 3 (double-sided brazing filler metal composite plate), core end plate 1, positioning rod 2, spacer sleeve 4, and U-shaped heat sink are cleaned with an alkaline and acid solution, then dried. Next, they are assembled, and flux is applied to each brazing joint. Then, based on the different heating characteristics, a brazing filler metal with a slightly lower liquidus line than the baffle plate 3 is applied to the core end plate 1. Because the core end plate 1 is 12mm thick and heats up more slowly than the baffle plate 3, and nitrogen-protected brazing is prone to melting due to temperature factors, this method avoids melting of the 2mm thick baffle plate 3 due to excessive temperature. Finally, a certain flow rate of nitrogen is introduced into the brazing furnace for nitrogen-protected brazing. After brazing, heat treatment is performed to improve material strength. Detailed processing methods are as follows: The first step is to machine the parts. This involves machining the baffle plate 3 (double-sided brazing composite plate), core end plate 1, positioning rod 2, spacer sleeve 4, U-shaped heat dissipation tube, cylinder 5, oil inlet and outlet end caps 6, and oil inlet and outlet components. The U-shaped heat dissipation tube has 12 different specifications with different bending radii (R3 to R12). The U-shaped heat dissipation tube is punched to enhance its heat dissipation performance. The brazing gap between the core end plate 1 and the U-shaped heat dissipation tube, and between the baffle plate 3 and the U-shaped heat dissipation tube, must be no more than 0.15mm.
[0025] Step 2: Parts cleaning. First, the parts (including core end plate 1, positioning rod 2, spacer sleeve 4, U-shaped heat sink and baffle plate 3) are alkaline washed and corroded in an alkaline solution (NaOH + NaCO3, 5% NaOH). Then, they are acid washed and neutralized in HNO3. During the alkaline washing and acid washing process, the U-shaped part of the U-shaped heat sink is only degreased, and the U-shaped part is positioned above the liquid during degreasing to prevent excessive corrosion caused by the alkaline and acid liquids not being able to drain easily. Finally, they are blown dry and dried at 140℃ for 3 hours.
[0026] Step 3: Assembly, first press... Figure 1 Assemble the frame, with the lower end of positioning rod 2 connected to the upper end of core end plate 1. The spacer sleeve 4, a hollow tube, is fitted onto positioning rod 2. Then, install baffle plate 3 onto positioning rod 2, controlling its position using spacer sleeve 4. Finally, install each U-shaped heat dissipation pipe from the inside out (see...). Figure 3 (As shown in the right image, installation proceeds from the center of the circular cross-section outwards towards the outer edge). Bending the aluminum alloy U-shaped heat sink should be avoided. The baffle plate 3 is a double-layer brazing filler plate; the main component of the brazing filler is 4045, with a liquidus temperature of 590℃. During the installation of the U-shaped heat sink, it is necessary to ensure that the end of the U-shaped heat sink extends at least 3mm beyond the core end plate 1 (refer to...). Figure 3 The end of the U-shaped heat pipe extends out Figure 3(The length of the left end dimension line at the 2mm mark on the left side shall not be less than 3mm). After the frame assembly is completed, apply flux to the baffle plate 3, with the application location being where the baffle plate 3 is assembled with the U-shaped radiator tube.
[0027] Step 4: Brazing filler metal coating. First, the auxiliary steel ring (with a TiCr film on its surface) is coated. This is because the core end plate 1 is brazed on the side corresponding to... Figure 3 The height of the left end face of the core end plate 1 above the brazing surface is only 2mm, while the effective brazing depth of the core end plate 1 is 8mm, and the spacing between each U-shaped heat dissipation tube is only 0.6mm. At the same time, the distance between the outermost U-shaped heat dissipation tube and the edge of the core end plate 1 is only 0.8mm. Faced with the long brazing depth and dense arrangement of U-shaped heat dissipation tubes (384 brazing joints), the amount of brazing filler metal required is large. Moreover, the brazing filler metal in the subsequent nitrogen-protected brazing contains flux, which further compresses the space of the brazing filler metal. Therefore, it is necessary to use an overlapping steel ring, using the axial height (2mm) of the steel ring as a barrier to prevent the brazing filler metal from overflowing, which increases the coating height of the brazing filler metal. With the steel ring with surface coating (vacuum-deposited TiCr film layer is used for 4045 brazing filler metal in this embodiment), the amount of brazing filler metal used is guaranteed. Next is the preparation of the solder and flux. The solder used is a self-mixed AI-Si series solder (near 4045 solder), with a liquidus temperature of 575℃ and in powder form. The flux is cesium fluoroaluminate, and the mixing ratio is 50:1 by mass, diluted appropriately with alcohol. Finally, the solder is coated. The solder is drawn up with a syringe and applied to the base of each U-shaped heatsink tube until it is flush with the end of the tube. (This is an indicator of the amount of solder used; the solder level with the end of the tube indicates the correct height. Too little solder means insufficient solder, too much will flow into the heatsink tube.) During the solder coating process, care should be taken to avoid solder flowing into the heatsink tube.
[0028] Step 5: Brazing. The aluminum alloy U-shaped heat sink has a wall thickness of only 0.1mm and is prone to erosion during nitrogen-protected brazing. Therefore, to solve this problem, a rapid heating method is adopted to raise the overall temperature of the aluminum alloy U-shaped tube radiator core assembly to 650℃ (this invention uses a non-vacuum brazing furnace, i.e., a common heating furnace that does not have a vacuum function or, although it has a vacuum function, does not meet the requirements of vacuum brazing; when a heating furnace with a vacuum function is selected, it can only evacuate the furnace to near 0Pa. The initial evacuation to near 0Pa pressure is mainly to expel the air in the furnace, and then a large amount of nitrogen is introduced for protection. When a heating furnace without a vacuum function is selected, nitrogen is introduced into the furnace and then extracted, and this process is repeated several times to purge the air in the furnace and form a nitrogen protective atmosphere. Because of this, the nitrogen-protected brazing cycle is only about 1 / 3 of the vacuum brazing time, resulting in significant cost reduction and efficiency improvement), and then the temperature is lowered to near the brazing temperature plateau to ensure rapid brazing completion; before the heating furnace is heated, 25m³ of nitrogen is introduced into the heating furnace. 3Nitrogen gas at a flow rate of / h is used to purge the air inside the furnace. The process involves two cycles of nitrogen injection and evacuation, followed by heating and a stable injection of 20m³. 3 Nitrogen gas is used for brazing at a rate of / h. After brazing is completed, the steel ring is removed.
[0029] Step 6: Heat treatment. The brazed aluminum alloy is in an annealed state, which causes a decrease in strength, especially for the core end plate 1 of the pressure-resistant component. In order to ensure strength, the aluminum alloy U-shaped tube heat sink core assembly is first solution treated at 520℃ and then aged at 170℃ for 8 hours. After heat treatment, the 6063 aluminum alloy core end plate 1 is tested for hardness and meets the T6 condition.
[0030] Step 7: Assembly. The first step is assembly. After machining and heat-treating the aluminum alloy U-shaped tube radiator core assembly, the aluminum alloy U-shaped tube radiator core assembly is installed into cylinder 5 (e.g., Figure 4 Then, assemble the fuel and lubricating oil inlet and outlet end caps 6 and the lubricating oil inlet and outlet assembly 7; next is laser welding. In order to reduce the impact of the outer ring fusion welding on the brazing of the U-shaped heat dissipation tubes in the internal aluminum alloy U-shaped tube-type radiator core assembly, laser welding is used to weld the two circumferential welds of the assembly ( Figure 4 The image shows two laser welds (8), with a laser welding power of 1.2KW, a frequency of 150HZ, and a scanning speed of 200mm / s; finally, a pressure test was conducted, which completed a maximum pressure test of 15MPa through a hydraulic pressure test.
[0031] The aluminum alloy U-shaped tube radiator processing method of the present invention is based on the heating characteristics of the aluminum alloy U-shaped tube radiator, namely, the core end plate 1 is 12mm thick and the effective brazing depth is 8mm, resulting in a lower heating depth at the core end plate 1 than other parts (baffle plate 3). If the same brazing filler metal is used, erosion at the brazing joint of baffle plate 3 is likely to occur. Therefore, based on the characteristics of heating and nitrogen-protected brazing, 4045 brazing filler metal is used in the faster heating area (baffle plate 3), and a near-4045 brazing filler metal is used in the slower heating area (core end plate 1). The brazing is completed in one step by utilizing the characteristic that the liquidus line of 4045 brazing filler metal is slightly higher than that of the self-prepared near-4045 brazing filler metal. Both brazing filler metals belong to the Al-Si system, but the Si content of the self-prepared near-4045 brazing filler metal is about 15% higher than that of 4045 brazing filler metal. In addition, the thickness of baffle plate 3 is only 2mm, and it is a double-sided brazing filler metal composite plate. The composite brazing filler metal is sufficient to meet the brazing requirements of the U-shaped heat pipe and baffle plate 3. The gaps between the U-shaped heat dissipation tubes in the core end plate 1, and the distance between the outermost U-shaped heat dissipation tube and the inner side of the core end plate 1, are only 0.6mm, with an effective brazing depth of 8mm. However, the outer edge height of the core end plate 1 is only 2mm. Even if the gaps in the core end plate 1 are filled with brazing filler metal using a syringe, it is insufficient to fill all the brazed joints (386 brazed joints) and form rounded corners on the back. To solve the problem of brazing filler metal quantity, this invention does not mechanically increase the outer edge height of the core end plate 1 as a margin for later machining removal, as this would increase workload and cause excess material and deformation. This invention uses a steel ring with the same diameter as the outer edge of the core end plate 1 and an axial height of 2mm. A TiCr film is then vacuum-deposited on the surface of the steel ring. Since 4045 brazing filler metal is an Al-Si based material, it cannot wet the TiCr film. The steel ring with the TiCr film then assists in filling the brazing filler metal, ultimately ensuring the correct amount of brazing filler metal is used.
[0032] Compared with the traditional riveting connection method for aluminum alloy U-shaped heat sinks, the present invention has the following advantages: First, it is more efficient. Riveting can only rivet the U-shaped heat sink tubes one by one, which is labor-intensive and inefficient. Brazing, on the other hand, can be mass-produced and has better quality consistency. Secondly, it has good temperature resistance. The riveted aluminum alloy U-shaped heat dissipation tube utilizes the plastic deformation of the rivet and the elastic deformation of the aluminum alloy U-shaped heat dissipation tube. In terms of operating temperature, most of them do not exceed 200℃. After exceeding the temperature, they will fail due to the temperature. At the same time, high temperature should be avoided when welding the cylinder 5. For brazed joints, they still have a certain connection strength at 500℃. Finally, brazing has higher strength. In riveting, the area near the edge plays a major connecting role, while in brazing, the entire gap is connected and plays a connecting role. Therefore, the strength of brazing is generally higher than that of riveting.
[0033] Compared with the traditional vacuum brazing method for aluminum alloy U-shaped heat sinks, the present invention has the following advantages: First, the cost is low. Vacuum brazing has a service life of no less than 10 hours, while the method of this invention can be completed in just 3 hours, which greatly shortens the processing cycle and reduces time and equipment usage costs. Secondly, based on the different heating characteristics of each component in the aluminum alloy U-shaped tube radiator core assembly, the corresponding brazing filler metal is adjusted to allow the aluminum alloy U-shaped tube radiator core assembly to be brazed as a whole in one go, thereby improving brazing efficiency. Finally, by depositing a TiCr film on the surface of the steel ring and taking advantage of the fact that Al-Si brazing filler metal cannot wet the TiCr film, the edge of the core end plate 1 is raised to form a space for filling the brazing filler metal. After brazing, it can be directly removed, providing sufficient brazing filler metal and reducing the amount of machining work before and after brazing.
[0034] Those skilled in the art can make various adjustments to this application based on the actual circumstances. The general principles defined in this application can be implemented in other embodiments without departing from their connotations. Therefore, this application is not limited to the structure shown in the specific embodiments, but is to be accorded the widest scope consistent with the principles and features set forth in the claims of this application.
Claims
1. A method for processing an aluminum alloy U-shaped tube-type radiator, characterized in that, include: Step 1: Parts processing. Complete the processing of parts including baffle plate, core end plate, positioning rod, spacer sleeve and U-shaped heat dissipation pipe. The baffle plate is a double-sided brazing composite plate. Ensure that the dimensions after processing are such that there is a brazing gap of no more than the set value between the core end plate and the U-shaped heat dissipation pipe, and between the baffle plate and the U-shaped heat dissipation pipe during subsequent assembly. Step 2: Parts cleaning. The parts to be brazed are degreased and treated with a combination of alkaline washing and acid washing. Then they are dried. Step 3: Assembly. First, assemble the baffle plate, core end plate, positioning rod and spacer set to form a frame. Then, install the free end of each U-shaped heat dissipation tube onto the core end plate, starting from the inside of the core end plate and working outwards. Step 4: Solder coating. A surface-coated ring is attached to the end face of the core end plate away from the U-shaped heat pipe. The coating layer of the ring should not wet the solder used for brazing the core end plate and the U-shaped heat pipe. This creates a solder filling area in the inner ring hole area of the ring, while the ring itself forms a barrier to ensure the amount of solder used between the core end plate and the U-shaped heat pipe. The liquidus line of the solder used for brazing the core end plate and the U-shaped heat pipe is lower than the liquidus line of the solder composite on the surface of the baffle plate. Step 5: Brazing. A non-vacuum brazing furnace is used to heat the material rapidly to a temperature higher than the brazing temperature, and then the temperature is cooled down to the brazing temperature plateau to quickly complete the brazing process and obtain the aluminum alloy U-shaped tube-type radiator core assembly. Step 6: Heat treatment. First, the aluminum alloy U-shaped tube radiator core assembly is subjected to solution treatment, followed by aging treatment. Step 7: Assembly processing. First, install the aluminum alloy U-shaped tube radiator core assembly into the cylinder. Then, assemble the fuel and lubricating oil inlet and outlet end caps and the lubricating oil inlet and outlet assembly. Next, use laser welding to weld the cylinder, the aluminum alloy U-shaped tube radiator core assembly, and the fuel and lubricating oil inlet and outlet end caps.
2. The method for processing an aluminum alloy U-shaped tube-type radiator according to claim 1, characterized in that: The first step also includes punching the surface of the U-shaped heat pipe.
3. The method for processing an aluminum alloy U-shaped tube radiator according to claim 1, characterized in that: In the second step, an alkaline wash is first performed using a solution of NaOH + NaCO3, followed by an acid wash and neutralization using HNO3.
4. The processing method of an aluminum alloy U-shaped tube radiator according to claim 1, characterized in that: In the second step, during the degreasing, alkaline washing, and acid washing processes, no degreasing agent, alkaline washing solution, or acid washing solution should remain inside the U-shaped part of the U-shaped heat dissipation tube.
5. The method for processing an aluminum alloy U-shaped tube-type radiator according to claim 1, characterized in that: In the third step, the lower end of the positioning rod is connected to the core end plate, the spacer sleeve is fitted onto the outside of the positioning rod, and the baffle plate is inserted into the positioning rod and contacts the end face of the spacer sleeve.
6. The method for processing an aluminum alloy U-shaped tube-type radiator according to claim 1, characterized in that: In the third step, the free end of the U-shaped heat sink is inserted into the assembly hole of the core end plate and then extends a certain distance out of the hole.
7. The method for processing an aluminum alloy U-shaped tube-type radiator according to claim 1, characterized in that: In the third step, flux is applied to the brazing joint between the baffle plate and the U-shaped heat sink. In the third step, flux is first applied to the brazing joint between the core end plate and the U-shaped heat sink. In the fourth step, the brazing filler metal and flux are mixed and then applied to the brazing joint between the core end plate and the U-shaped heat sink.
8. A method for processing an aluminum alloy U-shaped tube-type radiator according to claim 1, characterized in that: In the fourth step, the brazing filler metal used for brazing the core end plate and the U-shaped heat sink is the same series of brazing filler metal as the brazing filler metal composite on the surface of the baffle plate, and the liquidus line of the brazing filler metal is reduced by increasing or decreasing one or more of its elements.
9. A method for processing an aluminum alloy U-shaped tube-type radiator according to claim 1, characterized in that: In the fifth step, before heating, the non-vacuum brazing furnace is first filled with inert gas to purge the air inside the furnace, and then the inert gas is extracted. This process is repeated several times before heating and filling with inert gas to perform brazing.
10. A method for processing an aluminum alloy U-shaped tube-type radiator according to claim 1, characterized in that: In the sixth step, after aging treatment, the core end plate is subjected to hardness testing to determine whether the strength meets the requirements.