Brazing process for brazing aluminum alloy material

Abstract

The application provides a brazing process of an aluminum alloy material for brazing. The material of a runner plate used in the brazing process is an aluminum rare earth material, which comprises, in percentage by mass, 7.0-9.0% of a rare earth metal element RE, 0.4-0.6% of an Fe element, 0.6-1.2% of an Mn element, 0.3-0.5% of a Cr element, 0.02-0.15% of an Mg element, 0.1-0.2% of a Ti element, 0.02-0.2% of a V element, 0.02-0.1% of a B element, ≤0.1% of an Si element, ≤0.01% of a Cu element, the balance of an Al element and inevitable impurities, and ≤0.05% of a single impurity element. After brazing by the brazing process, the weld is full and has high strength, and the brazing process is suitable for brazing of runner plates with various complex structures.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy technology, and more specifically, to a brazing process for aluminum alloy materials used in brazing. Background Technology

[0002] Brazing is a welding method in which both the workpiece and a filler metal with a flux with a melting point lower than the workpiece's melting point are simultaneously heated to the flux's melting temperature. The liquid flux then fills the gaps in the solid workpiece to join the metals. Brazing aluminum alloys typically requires the use of an appropriate protective atmosphere to ensure a high-quality bond and prevent oxidation. Argon or nitrogen is commonly used as the protective atmosphere for aluminum alloy brazing because these gases effectively reduce the presence of oxygen, thus preventing oxidation.

[0003] Adding rare earth metal elements to brazing aluminum alloys helps to form high eutectic points and high-temperature stable phases, thus creating a brazable aluminum alloy system framework. By controlling the content of rare earth metal elements, the synergistic effect between the elements is enhanced, resulting in a uniform microstructure and fine grains in the aluminum alloy, which exhibits good castability, fluidity, hot crack resistance, and weldability.

[0004] Because the thermal management module flow channel plate integrates a large number of sub-components and needs to implement multiple different operating modes, its structure is very compact and complex. Currently commonly used processes include laser welding, friction stir welding, and vacuum brazing. Laser welding releases a significant amount of heat at the weld joint, easily causing deformation of the flow channel plate, making it unsuitable for complex flow channels. Friction stir welding has limitations on part wall thickness, generally requiring a wall thickness ≥4mm, which is difficult to meet the requirements for lightweight parts. Vacuum brazing requires high precision in part machining, and continuous vacuum brazing furnaces are expensive, resulting in very high production investment.

[0005] Therefore, there is an urgent need for a brazing method suitable for nitrogen protection of die-cast flow channel plates of aluminum alloys containing rare earth elements, in order to solve the technical problem that the above-mentioned aluminum alloys containing rare earth elements and manufactured by die casting, as well as aluminum alloys with large wall thickness variations and complex structures, are not suitable for current nitrogen-protected brazing. Summary of the Invention

[0006] The main objective of this invention is to provide a brazing process for aluminum alloy materials for brazing, so as to solve the problem that the brazing process for aluminum alloy materials for brazing in the prior art is relatively limited.

[0007] To achieve the above objectives, according to one aspect of the present invention, a brazing process for an aluminum alloy material for brazing is provided. The brazing process includes: sequentially performing degreasing, drying, preheating, brazing, and cooling steps on the aluminum alloy material for brazing. The material of the flow channel plate used in the brazing process is an aluminum rare earth material, which, by mass percentage, comprises: 7.0–9.0% rare earth metal element RE, 0.4–0.6% Fe, 0.6–1.2% Mn, 0.3–0.5% Cr, 0.02–0.15% Mg, 0.1–0.2% Ti, and 0.02–0.2% [unspecified element]. The aluminum alloy base plate used in the brazing process has a flux protective layer on its outer surface, which is an integral design with the aluminum alloy base plate. The brazing temperature is set at 620℃~630℃, and the brazing time does not exceed 30 minutes. The aluminum alloy base plate includes a core material, an Al-Si brazing composite layer and a flux protective layer sequentially covering the surface of the core material. The Al-Si brazing composite layer is in contact with the core material and is made of AA4045Al-Si alloy.

[0008] Furthermore, in the aforementioned aluminum alloy materials for brazing, Al 11 The mass percentage of RE3 phase is 12-15%, the mass percentage of Al6Mn phase is 2.5-4.5%, the mass percentage of Al7Cr phase is 1.5-2.5%; and / or the rare earth metal element RE is La and Ce, preferably with a mass ratio of La to Ce of 2.0-3.0:1.

[0009] Furthermore, the thickness of the aforementioned flow channel plate is 2.5–3.5 mm, and / or the solidus temperature of the flow channel plate material is 625 °C, and the liquidus temperature of the flow channel plate material is 642–644 °C; and / or the assembly gap between the flow channel plate and the aluminum alloy base plate is ≤0.2 mm.

[0010] Furthermore, the thickness of the aforementioned pre-embedded flux protective layer is 1 to 4% of the thickness of the aluminum alloy base plate.

[0011] Furthermore, the brazing time is 25 to 30 minutes.

[0012] Furthermore, the aforementioned aluminum alloy base plate is made of 3-series aluminum alloy, and / or the core material is model AA3003MOD.

[0013] Furthermore, the thickness of the Al-Si solder composite layer is 7.5 to 12.5% ​​of the thickness of the aluminum alloy base plate; and / or the thickness of the aluminum alloy base plate is 2.8 to 3.2 mm.

[0014] Furthermore, prior to the above degreasing step, the aluminum alloy material for brazing is baked at a temperature of 550–610°C and / or for a time of 1–3 hours.

[0015] Furthermore, the above brazing is performed in a nitrogen atmosphere, wherein the oxygen content in the nitrogen atmosphere is ≤10ppm.

[0016] Furthermore, between the above degreasing and drying, the welding surfaces of the flow channel plate and the aluminum alloy base plate are ultrasonically cleaned at a frequency of 25–28 kHz for a duration of 30–40 min.

[0017] By applying the technical solution of this invention, this application, through the addition of rare earth metal element RE to brazing aluminum alloy materials, facilitates the formation of high eutectic points and high-temperature stable phases, thereby forming a brazable aluminum alloy material system framework. Adding Fe, Mn, and Cr elements to brazing aluminum alloy materials improves anti-sticking properties during die casting. Adding Mg element helps improve solid solution strengthening. Adding Ti, V, and B elements helps achieve microstructure homogeneity and prevent segregation. Controlling the amount of Si element added within the above range helps to maximize its synergistic effect with other elements and ensures that the solidus and liquidus temperatures of the flow channel plate used in the brazing process are within a reasonable preset range. By controlling the content of rare earth metal elements in aluminum rare earth materials within the above range, it is beneficial to improve the stability and welding quality of aluminum rare earth materials during brazing and to keep the solidus and liquidus temperatures of the flow channel plate material within a suitable range. Meanwhile, because the outer surface of the aluminum alloy base plate used in the brazing process has a flux protective layer, and the flux protective layer and the aluminum alloy base plate are designed as an integral unit, it helps to reduce oxidation during welding, thereby improving the strength and airtightness of the weld, while also promoting the flow and wetting of the brazing filler metal. The brazing process of this invention produces a full and high-strength weld. In empirical burst tests, the burst failure pressure of the flow channel plate can reach over 90 bar, making it suitable for brazing flow channel plates with various complex structures. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0019] Figure 1 The diagram shows the burst pressure test results of a brazed aluminum alloy material according to Embodiment 1 of the brazing process of the present invention;

[0020] Figure 2 The diagram shows the burst pressure test results of a brazed aluminum alloy material according to Embodiment 2 of the brazing process of the present invention;

[0021] Figure 3 The diagram shows the burst pressure test results of a brazed aluminum alloy material according to embodiment 3 of the brazing process of the present invention;

[0022] Figure 4 The diagram shows the burst pressure test results of a brazed aluminum alloy material according to Example 4 of the brazing process of the present invention. Detailed Implementation

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0024] As analyzed in the background section, the existing technology has the problem that the brazing process for aluminum alloy materials for brazing is relatively limited. In order to solve this problem, the present invention provides a brazing process for aluminum alloy materials for brazing.

[0025] In a typical embodiment of this application, a brazing process for an aluminum alloy material is provided. This brazing process includes the following steps: degreasing, drying, preheating, brazing, and cooling of the aluminum alloy material. The characteristic feature is that the flow channel plate used in the brazing process is made of aluminum rare earth material, comprising, by mass percentage: 7.0–9.0% rare earth metal element RE, 0.4–0.6% Fe, 0.6–1.2% Mn, 0.3–0.5% Cr, 0.02–0.15% Mg, 0.1–0.2% Ti, and 0.02–0.2% [unspecified element]. The aluminum alloy base plate contains 0.02-0.1% V, 0.1%-0.1% B, ≤0.1%-0.1%-0.01%-0.01%-0.05% Al and unavoidable impurities, with each impurity element having a content of ≤0.05%. The outer surface of the aluminum alloy base plate used in the brazing process has a flux protective layer, which is an integral design with the aluminum alloy base plate. The brazing temperature is set at 620℃-630℃, and the brazing time does not exceed 30 minutes. The aluminum alloy base plate includes a core material, an Al-Si brazing composite layer sequentially covering the surface of the core material, and a flux protective layer. The Al-Si brazing composite layer is in contact with the core material, and the Al-Si brazing composite layer is of type AA4045Al-Si alloy.

[0026] This application utilizes rare earth metal element RE to add to brazing aluminum alloy materials, which facilitates the formation of high eutectic points and high-temperature stable phases, thereby creating a brazable aluminum alloy material system framework. Adding Fe, Mn, and Cr elements to the brazing aluminum alloy material improves anti-sticking properties during die casting. Adding Mg helps improve solid solution strengthening. Adding Ti, V, and B elements helps achieve microstructure homogeneity and prevent segregation. Controlling the amount of Si added within the above range helps to maximize its synergistic effect with other elements and ensures that the solidus and liquidus temperatures of the flow channel plate used in the brazing process are within a reasonable preset range. By controlling the content of rare earth metal elements in the aluminum rare earth material within the above range, it is beneficial to improve the stability and weld quality of the aluminum rare earth material during brazing and to keep the solidus and liquidus temperatures of the flow channel plate material within a suitable range. Meanwhile, because the outer surface of the aluminum alloy base plate used in the brazing process has a flux protective layer, and the flux protective layer and the aluminum alloy base plate are designed as an integral unit, it helps to reduce oxidation during welding, thereby improving the strength and airtightness of the weld, while also promoting the flow and wetting of the brazing filler metal. The brazing process of this invention produces a full and high-strength weld. In empirical burst tests, the burst failure pressure of the flow channel plate can reach over 90 bar, making it suitable for brazing flow channel plates with various complex structures.

[0027] Furthermore, the Al-Si composite layer and the integrated flux protection layer provide good melting point compatibility and welding performance. The Al-Si brazing filler metal composite layer is further selected as AA4045Al-Si alloy, whose liquidus temperature is conducive to brazing, thereby improving the structural integrity and burst pressure of the flow channel plate.

[0028] The actual temperature that can be achieved during brazing is about 10°C lower than the set temperature.

[0029] In one embodiment of this application, in the above-mentioned aluminum alloy material for brazing, Al 11 The mass percentage of RE3 phase is 12-15%, preferably 14-15%; the mass percentage of Al6Mn phase is 2.5-4.5%, preferably 2.71-4.21%; the mass percentage of Al7Cr phase is 1.5-2.5%, preferably 1.76-2.34%; and / or the rare earth metal element RE is La and Ce, preferably with a mass ratio of La to Ce of 2.0-3.0:1.

[0030] Preferred control of AI 11Maintaining the mass percentage of the RE3 phase within the aforementioned range helps improve the casting performance of brazing aluminum alloys. Dispersed Al6Mn and Al7Cr phases are beneficial for suppressing the growth of recrystallized grains in aluminum alloys; controlling the mass percentage of Al6Mn and Al7Cr phases within the aforementioned range facilitates better grain refinement. Controlling the type of rare earth element RE and its ratio with Ce helps optimize the alloy's microstructure, forming a more stable high-temperature phase, ensuring the material's performance at high temperatures, thereby reducing cracks and voids during welding and enhancing the airtightness and mechanical properties of the aluminum alloy.

[0031] In one embodiment of this application, the thickness of the flow channel plate is 2.5 to 3.5 mm, and / or the solidus temperature of the flow channel plate material is 625°C, and the liquidus temperature of the flow channel plate material is 642 to 644°C; and / or the assembly gap between the flow channel plate and the aluminum alloy base plate is ≤0.2 mm.

[0032] Controlling the solid-liquid line temperature of the flow channel plate material within the aforementioned range facilitates the brazing process. Maintaining the solid-liquid line temperature within this range improves welding efficiency and quality, reduces aluminum alloy deformation, and also meets the requirements for lightweight components and structural complexity.

[0033] In one embodiment of this application, the thickness of the aforementioned pre-embedded flux protective layer is 1 to 4% of the thickness of the aluminum alloy base plate.

[0034] The integrated design of the flux protective layer and the aluminum alloy base plate helps to reduce the amount of flux protective layer used. Furthermore, it is preferable to control the ratio of the thickness of the flux protective layer to the thickness of the aluminum alloy base plate within the above range. This is beneficial for the flux to fully cover and protect the surface of the aluminum alloy base plate, reduce oxidation and contamination, and improve the cleanliness of the welding area. This is conducive to improving the reliability of the weld, while also reducing material waste and saving costs.

[0035] In one embodiment of this application, the time is 25 to 30 minutes.

[0036] Preferably controlling the brazing time within the above range is beneficial for improving the fluidity and full melting of the brazing filler metal, while avoiding deformation or performance degradation caused by overheating of the aluminum alloy material. It also improves efficiency and is suitable for industrial mass production.

[0037] To further promote a strong connection between the aluminum alloy base plate and the flow channel plate material during the welding process, in some preferred embodiments of this application, the aluminum alloy base plate is made of 3-series aluminum alloy, and / or the core material is AA3003MOD.

[0038] In one embodiment of this application, the thickness of the Al-Si solder composite layer is 7.5 to 12.5% ​​of the thickness of the aluminum alloy base plate; and / or the thickness of the aluminum alloy base plate is 2.8 to 3.2 mm.

[0039] Controlling the range of the above conditions is beneficial to improving the melting and flow of the composite layer during the brazing process, as well as its good bonding with the base plate material. This is conducive to improving welding efficiency, increasing the strength and pressure resistance of the welded joint, and meeting the high-performance requirements of the flow channel plate.

[0040] In one embodiment of this application, prior to the above-mentioned degreasing step, the aluminum alloy material for brazing is baked at a temperature of 550–610°C and / or for a duration of 1–3 hours.

[0041] Baking the aluminum alloy material for brazing before the degreasing step helps remove moisture and residues from the surface, improving its cleanliness. Preferably controlling the baking temperature and time within the aforementioned range promotes faster drying of the aluminum alloy surface without damaging its microstructure. Controlling these conditions improves the quality of the weld surface, reduces welding defects, and provides a better welding environment for subsequent brazing steps.

[0042] In one embodiment of this application, the above-mentioned brazing is performed in a nitrogen atmosphere, wherein the oxygen content in the nitrogen atmosphere is ≤10ppm.

[0043] This application employs nitrogen-shielded welding for brazing flow channel plates. Because the nitrogen-shielded tunnel furnace provides uniform brazing temperature, it helps reduce deformation caused by uneven heating. Since the mechanism of nitrogen-shielded welding involves the melting and joining of composite layers with the base material, the wall thickness requirement is not high, which can meet the requirements for lightweight parts. Nitrogen-shielded welding equipment is relatively common, with a fast production cycle and high efficiency, making it very suitable for mass production in factories. Simultaneously, by controlling the oxygen content in the nitrogen atmosphere within the aforementioned range, a purer welding environment is achieved, improving the strength and airtightness of the weld joint and reducing contamination and oxidation during the welding process.

[0044] In one embodiment of this application, between the above degreasing and drying, the welding surfaces of the flow channel plate and the aluminum alloy base plate are ultrasonically cleaned. The ultrasonic cleaning frequency is 25-28 kHz and the ultrasonic cleaning time is 30-40 min.

[0045] Ultrasonic cleaning utilizes the cavitation effect of ultrasound to effectively remove oil and oxides from the welding surface, providing a clean welding surface for brazing. Preferably controlling the frequency and duration of ultrasonic cleaning within the aforementioned range is beneficial for improving the cleanliness of the welding surface, reducing welding defects, improving welding quality and the performance of the flow channel plate, thereby enhancing the overall product reliability and service life.

[0046] Furthermore, the aluminum alloy material for the flow channel plate obtained by the brazing method of this application preferably has a tensile strength of 187.7-198.5 MPa, a yield strength of 80.2-93.8 MPa, an elongation at break of 10.0-19.1%, and an electrical conductivity of 16.0-16.7 ms / m.

[0047] The beneficial effects of this application will be explained below with reference to specific embodiments and comparative examples.

[0048] Examples of preparation of aluminum alloy materials for flow channel plates:

[0049] Example 1

[0050] The aluminum alloy material used for the flow channel plate in this embodiment is composed of the following mass percentages: 5.7% La, 2.3% Ce, 0.6% Fe, 0.8% Mn, 0.5% Cr, 0.05% Mg, 0.15% Ti, 0.05% V, 0.03% B, 0.09% Si, 0.01% Cu, and the remainder is aluminum.

[0051] Preparation steps:

[0052] Step 1: According to the above mass percentage, add industrial pure aluminum ingots into a crucible resistance furnace and heat to 750°C until the pure aluminum ingots are completely melted. Then, add the other components of the preset composition except for aluminum, that is, add the other element components in the above mass percentage composition except for aluminum to obtain aluminum alloy liquid.

[0053] Step 2: The aluminum alloy sodium-free refining agent ZS-AJ6 is pressed in through a degassing machine for refining and degassing for 20 minutes to remove gas from the molten aluminum.

[0054] Step 3: Check whether the effective aluminum alloy liquid composition meets the usage standard. If yes, proceed to Step 4. If no, the original mass percentage of a certain element in the aluminum alloy liquid does not reach the preset mass percentage. It is necessary to add an additional mass percentage of the element to adjust the mass percentage of the element in the effective aluminum alloy liquid so that the mass percentage of the element meets the usage standard, that is, reaches the preset mass percentage.

[0055] Step 4: Detect the gas content using a hydrogen analyzer. If the gas content is below 0.15 mL / 100g, die-cast the product using a high-pressure die-casting device. If the gas content does not meet the standard, continue with the refining and degassing process in Step 2.

[0056] Step 5: Die casting is performed using an 1100T die casting machine. The die casting temperature is 720℃, the mold cavity vacuum degree is 35mBar, the casting pressure is 31.5MPa, the injection speed is 2.5m / s, the mold temperature is 130℃, and the aluminum alloy liquid temperature is 690℃ to obtain aluminum alloy material for runner plate.

[0057] Example 2

[0058] The difference from Example 1 is that the aluminum alloy material for the flow channel plate is composed of the following mass percentages: 5.5% La, 2.5% Ce, 0.6% Fe, 1.0% Mn, 0.45% Cr, 0.10% Mg, 0.15% Ti, 0.15% V, 0.04% B, 0.09% Si, 0.01% Cu, with the remainder being aluminum, thus obtaining the aluminum alloy material for the flow channel plate.

[0059] Example 3

[0060] The difference from Example 1 is that the aluminum alloy material for the flow channel plate is composed of the following mass percentages: 5.0% La, 4.0% Ce, 0.4% Fe, 0.9% Mn, 0.3% Cr, 0.08% Mg, 0.1% Ti, 0.02% V, 0.07% B, 0.09% Si, 0.01% Cu, with the remainder being aluminum, thus obtaining the aluminum alloy material for the flow channel plate.

[0061] Example 4

[0062] The difference from Example 1 is that the sum of the mass ratios of La and Ce is 8%, and the mass ratio of La to Ce is 3:1, ultimately yielding an aluminum alloy material for the flow channel plate.

[0063] Example 5

[0064] The difference from Example 1 is that the sum of the mass ratios of La and Ce is 8%, and the mass ratio of La to Ce is 2:1, ultimately yielding an aluminum alloy material for the flow channel plate.

[0065] Comparative Example 1

[0066] The difference from Example 1 is that the aluminum alloy material for the flow channel plate is composed of the following mass percentages: 5.0% La, 2% Ce, 2.5% Fe, 0.5% Mn, 0.8% Cr, 0.10% Mg, 0.1% Ti, 0.12% V, 0.05% B, 0.15% Si, 0.02% Cu, with the remainder being aluminum. The resulting aluminum alloy material for the flow channel plate has a solidus temperature of 607°C.

[0067] In the aluminum alloy materials for flow channel plates prepared in the above embodiments and comparative examples, Al 11 The proportions of RE3 phase, Al6Mn phase and Al7Cr phase are shown in Table 1.

[0068] Table 1

[0069] Implementation / Comparative Example <![CDATA[Al 11 RE3 percentage (%) <![CDATA[Percentage of Al6Mn phase (%)]]> <![CDATA[Percentage of Al7Cr phase (%)]]> Example 1 14 2.71 2.34 Example 2 14 4.11 2.17 Example 3 15 3.35 1.76 Example 4 14 4.13 1.92 Example 5 14 4.21 1.91 Comparative Example 1 12 1.26 2.18

[0070] The aluminum alloy materials for flow channel plates prepared in the above embodiments and comparative examples were wire-cut according to the GBT228 standard test pieces, and their tensile strength, yield strength, elongation at break and electrical conductivity were tested. The test results are shown in Table 2.

[0071] Table 2

[0072]

[0073]

[0074] The brazing feasibility of the aluminum alloys used for flow channel plates prepared in the above embodiments and comparative examples was tested using gas shielded welding.

[0075] Brazing process example 1

[0076] The flow channel plate (made of aluminum alloy as described in Example 1) and the aluminum alloy base plate are assembled and clamped using brazing fixtures. The assembly gap is required to be 0.1 mm, and the thickness of the flow channel plate is 3 mm. The aluminum alloy base plate is made of 3-series aluminum alloy (manufactured by machining, stamping, forging, or die casting). The aluminum alloy base plate includes a core material, an Al-Si solder composite layer and a flux protective layer sequentially covering the surface of the core material. The Al-Si solder composite layer is in contact with the core material. The core material is AA3003MOD, with a solidus temperature of 625°C and a liquidus temperature of 648°C. The thickness of the Al-Si solder composite layer is 7.5% of the thickness of the aluminum alloy base plate. The Al-Si solder composite layer is AA4045Al-Si alloy, with solidus and liquidus temperatures of 577°C and 590°C, respectively. The thickness of the aluminum alloy base plate is 3 mm.

[0077] Baking (550℃ for 1 hour), degreasing, drying, preheating, brazing, and cooling.

[0078] The flux protective layer and the aluminum alloy base plate are integrated into a single design (the flux is injected into the solder using spray forming technology, combined with a rolling process to create a standard composite assembly. In actual CAB production, spraying flux is not required), and the thickness of the pre-embedded flux protective layer is 2.5% of the thickness of the aluminum alloy base plate.

[0079] Degreasing was performed in a furnace at 110℃. The weld surfaces of the flow channel plate and the aluminum alloy base plate were ultrasonically cleaned at a frequency of 26.5kHz for 35 minutes each. Afterwards, the material was dried at 290℃ and preheated in a furnace at 560℃. Brazing was then performed in a furnace at 620℃ for 30 minutes. While meeting brazing requirements, the brazing temperature was kept as low as possible to reduce weld diffusion and erosion, thereby improving weld strength. Finally, the material was cooled by water or air to complete the brazing process, resulting in the brazed aluminum alloy material. The burst pressure test results of the brazed aluminum alloy material are shown in the figure below. Figure 1 As shown. It should be noted that due to the special properties of this material, the oxygen and moisture content in the furnace cavity should be controlled. The protective atmosphere requires high-purity nitrogen, the oxygen content in the furnace cavity should be 10 ppm, and the nitrogen dew point should be controlled below -40℃.

[0080] Brazing process example 2

[0081] The difference from Example 1 of the brazing process is that the brazing temperature was set to 620℃ and the brazing time was 25 minutes, resulting in a brazed aluminum alloy material. The burst pressure test results of this brazed aluminum alloy material are shown in the figure below. Figure 2 As shown.

[0082] Brazing process example 3

[0083] The difference from Example 1 of the brazing process is that the brazing temperature was set to 630℃ and the brazing time was 30 minutes, resulting in a brazed aluminum alloy material. The burst pressure test results of this brazed aluminum alloy material are shown in the figure below. Figure 3 As shown.

[0084] Brazing process example 4

[0085] The difference from Example 1 of the brazing process is that the brazing temperature was set to 630℃ and the brazing time was 25 minutes, resulting in a brazed aluminum alloy material. The burst pressure test results of this brazed aluminum alloy material are shown in the figure below. Figure 4 As shown.

[0086] Brazing process example 5

[0087] The difference from the brazing process in Example 1 is that the flow channel plate uses the aluminum alloy material of the flow channel plate in Example 2, and the final brazed aluminum alloy material is obtained.

[0088] Brazing process example 6

[0089] The difference from the brazing process in Example 1 is that the flow channel plate uses the aluminum alloy material of the flow channel plate in Example 3, and the final brazed aluminum alloy material is obtained.

[0090] Brazing process example 7

[0091] The difference from Example 1 of the brazing process is that the flow channel plate uses the aluminum alloy material of Example 4, and the final brazed aluminum alloy material is obtained.

[0092] Brazing process example 8

[0093] The difference from Example 1 of the brazing process is that the flow channel plate uses the aluminum alloy material of Example 5, and the final brazed aluminum alloy material is obtained.

[0094] Brazing process comparison example 1

[0095] The difference from Example 1 of the brazing process is that the brazing temperature is set to 610°C and the brazing time is 50 minutes, resulting in a brazed aluminum alloy material.

[0096] Brazing process comparison example 2

[0097] The difference from Example 1 of the brazing process is that the brazing temperature was set to 610°C and the brazing time was 40 minutes, resulting in a brazed aluminum alloy material.

[0098] Brazing process comparison example 3

[0099] The difference from Example 1 of the brazing process is that the brazing temperature was set to 610°C and the brazing time was 30 minutes, resulting in a brazed aluminum alloy material.

[0100] Brazing process comparison example 4

[0101] The difference from Example 1 of the brazing process is that the brazing temperature was set to 610°C and the brazing time was 25 minutes, resulting in brazed aluminum alloy material.

[0102] Brazing process comparison example 5

[0103] The difference from Example 1 of the brazing process is that the brazing temperature was set to 620°C and the brazing time was 50 minutes, resulting in brazed aluminum alloy material.

[0104] Brazing process comparison example 6

[0105] The difference from Example 1 of the brazing process is that the brazing temperature was set to 620°C and the brazing time was 40 minutes, resulting in a brazed aluminum alloy material.

[0106] Brazing process comparison example 7

[0107] The difference from Example 1 of the brazing process is that the brazing temperature was set to 630°C and the brazing time was 50 minutes, resulting in brazed aluminum alloy material.

[0108] Brazing process comparison example 8

[0109] The difference from Example 1 of the brazing process is that the brazing temperature was set to 630°C and the brazing time was 40 minutes, resulting in a brazed aluminum alloy material.

[0110] Brazing process comparison example 9

[0111] The difference from Example 1 of the brazing process is that the flow channel plate uses the aluminum alloy material of the flow channel plate of Comparative Example 1, and the final brazed aluminum alloy material is obtained.

[0112] Brazing process comparison example 10

[0113] The difference from Example 1 of the brazing process is that the process involves baking (baking at 550℃ for 1 hour), applying flux, degreasing, drying, preheating, brazing, and cooling. A flux spraying device is used to spray flux onto the AA3003 / AA4045 aluminum plate, ultimately obtaining the brazed aluminum alloy material.

[0114] Brazing process comparison example 11

[0115] The difference from Example 1 of the brazing process is that the brazing temperature is set at 630°C, and the Al-Si brazing filler metal composite layer is AA4343Al-Si alloy with a solidus temperature of 577°C and a liquidus temperature of 613°C.

[0116] The aluminum alloy materials obtained from the above brazing process examples and brazing process comparison examples were subjected to air tightness tests and burst pressure tests. The test conditions and test results are recorded as follows:

[0117] Brazing process example 1

[0118]

[0119] Brazing process example 2

[0120]

[0121] Brazing process example 3

[0122]

[0123] Brazing process example 4

[0124]

[0125] Brazing process example 5

[0126]

[0127] Brazing process example 6

[0128]

[0129] Brazing process example 7

[0130]

[0131] Brazing process example 8

[0132]

[0133] Brazing process comparison example 1

[0134]

[0135]

[0136] Brazing process comparison example 2

[0137]

[0138] Brazing process comparison example 3

[0139]

[0140] Brazing process comparison example 4

[0141]

[0142] Brazing process comparison example 5

[0143]

[0144] Brazing process comparison example 6

[0145]

[0146] Brazing process comparison example 7

[0147]

[0148] Brazing process comparison example 8

[0149]

[0150] Brazing process comparison example 9

[0151]

[0152] Brazing process comparison example 10

[0153]

[0154] Brazing process comparison example 11

[0155]

[0156] In summary, the above verification shows that for die-cast flow channel plate parts containing aluminum rare elements, the brazing zone temperature is set at 620℃~630℃, so that the actual temperature of the flow channel plate body is 605℃~615℃. The brazing time is 25~30min, and the welding strength and weld rate meet the requirements of airtightness and burst pressure test.

[0157] Among them, the brazing process in Comparative Example 10 had poor cleanliness due to flux residue.

[0158] Compared with Example 1 of the brazing process, the Al-Si brazing composite layer in Comparative Example 11 of the brazing process was changed to AA4043Al-Si alloy, which has an increased liquidus temperature, which is not conducive to brazing and causes explosion, which is unacceptable.

[0159] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0160] This application utilizes rare earth metal element RE to add to brazing aluminum alloy materials, which facilitates the formation of high eutectic points and high-temperature stable phases, thereby creating a brazable aluminum alloy material system framework. Adding Fe, Mn, and Cr elements to the brazing aluminum alloy material improves anti-sticking properties during die casting. Adding Mg helps improve solid solution strengthening. Adding Ti, V, and B elements helps achieve microstructure homogeneity and prevent segregation. Controlling the amount of Si added within the above range helps to maximize its synergistic effect with other elements and ensures that the solidus and liquidus temperatures of the flow channel plate used in the brazing process are within a reasonable preset range. By controlling the content of rare earth metal elements in the aluminum rare earth material within the above range, it is beneficial to improve the stability and weld quality of the aluminum rare earth material during brazing and to keep the solidus and liquidus temperatures of the flow channel plate material within a suitable range. Meanwhile, because the outer surface of the aluminum alloy base plate used in the brazing process has a flux protective layer, and the flux protective layer and the aluminum alloy base plate are designed as an integral unit, it helps to reduce oxidation during welding, thereby improving the strength and airtightness of the weld, while also promoting the flow and wetting of the brazing filler metal. The brazing process of this invention produces a full and high-strength weld. In empirical burst tests, the burst failure pressure of the flow channel plate can reach over 90 bar, making it suitable for brazing flow channel plates with various complex structures.

[0161] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A brazing process for aluminum alloy materials used in brazing, the brazing process comprising: The method for sequentially performing degreasing, drying, preheating, brazing, and cooling steps on aluminum alloy materials for brazing is characterized in that the material of the flow channel plate used in the brazing process is an aluminum rare earth material, which, by mass percentage, comprises: 7.0–9.0% rare earth metal element RE, 0.4–0.6% Fe, 0.6–1.2% Mn, 0.3–0.5% Cr, 0.02–0.15% Mg, 0.1–0.2% Ti, 0.02–0.2% V, 0.02–0.1% B, ≤0.1% Si, ≤0.01% Cu, with the balance being Al and unavoidable impurities, and the content of a single impurity element being ≤0.05%. The outer surface of the aluminum alloy base plate used in the brazing process has a flux protective layer, and the flux protective layer and the aluminum alloy base plate are integrated into the design. The brazing temperature is set at 620℃~630℃, and the brazing time does not exceed 30 minutes; The aluminum alloy base plate includes a core material, an Al-Si solder composite layer sequentially covering the surface of the core material, and a flux protective layer. The Al-Si solder composite layer is in contact with the core material, and the Al-Si solder composite layer is of type AA4045Al-Si alloy.

2. The brazing process according to claim 1, characterized in that, In the aluminum alloy material used for brazing, Al 11 The mass percentage of RE3 phase is 12-15%, the mass percentage of Al6Mn phase is 2.5-4.5%, and the mass percentage of Al7Cr phase is 1.5-2.5%; and / or the rare earth metal element RE is La and Ce, preferably the mass ratio of La to Ce is 2.0-3.0:

1.

3. The brazing process according to claim 1 or 2, characterized in that, The thickness of the flow channel plate is 2.5 to 3.5 mm, and / or the solidus temperature of the flow channel plate material is 625°C, and the liquidus temperature of the flow channel plate material is 642 to 644°C. And / or the assembly gap between the flow channel plate and the aluminum alloy base plate is ≤0.2mm.

4. The brazing process according to any one of claims 1 to 3, characterized in that, The thickness of the pre-embedded flux protective layer is 1 to 4% of the thickness of the aluminum alloy base plate.

5. The brazing process according to any one of claims 1 to 4, characterized in that, The brazing time is 25 to 30 minutes.

6. The brazing process according to any one of claims 1 to 5, characterized in that, The aluminum alloy base plate is made of 3-series aluminum alloy, and / or the core material is model AA3003MOD.

7. The brazing process according to any one of claims 1 to 6, characterized in that, The thickness of the Al-Si solder composite layer is 7.5 to 12.5% ​​of the thickness of the aluminum alloy base plate; and / or the thickness of the aluminum alloy base plate is 2.8 to 3.2 mm.

8. The brazing process according to any one of claims 1 to 7, characterized in that, Prior to the degreasing step, the aluminum alloy material for brazing is baked at a temperature of 550–610°C and / or for a duration of 1–3 hours.

9. The brazing process according to any one of claims 1 to 8, characterized in that, The brazing is performed in a nitrogen atmosphere, wherein the oxygen content in the nitrogen atmosphere is ≤10ppm.

10. The brazing process according to any one of claims 1 to 9, characterized in that, Between the degreasing and drying processes, the welding surfaces of the flow channel plate and the aluminum alloy base plate are ultrasonically cleaned. The ultrasonic cleaning frequency is 25–28 kHz, and the ultrasonic cleaning time is 30–40 min.

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