Aluminum-silicon-copper brazing filler metal powder and integrated preparation method and device thereof

Abstract

The application relates to the technical field of brazing materials, in particular to an aluminum-silicon-copper brazing filler powder and an integrated preparation method and device thereof, the integrated preparation device of the aluminum-silicon-copper brazing filler powder comprises a grinding container, a plurality of metal blocks with a preset thickness are accommodated in the grinding container, a rotating shaft is arranged in the grinding container, and the rotating shaft can rotate around a first axis. The integrated device of the aluminum-silicon-copper brazing filler powder used by the application is provided with a liquid nitrogen spraying pipe which sprays liquid nitrogen into the grinding container to promote the brittle pulverization of the metal blocks, is provided with a rotating shaft and a cutting tool which cut and grind the metal blocks in the grinding container, is provided with an auger screw which conveys the aluminum-silicon-copper brazing filler powder brittle pulverized in the grinding container to a filter plate for filtration, so that the finished aluminum-silicon-copper brazing filler powder is obtained, the entire production process does not need to use atomization equipment, the crushing, grinding, oxygen removal and filtration of the metal blocks can be realized through one set of equipment, the equipment has low manufacturing cost, and the powder preparation efficiency is high.

Description

Technical Field

[0001] This invention relates to the field of brazing materials technology, and in particular to an aluminum-silicon-copper brazing filler powder and its integrated preparation method and apparatus. Background Technology

[0002] Brazing is a welding technique that uses a filler metal with a melting temperature lower than that of the base metal, and operates at a temperature below the solidus of the base metal but above the liquidus of the filler metal. The molten filler metal then joins the base metals together. Brazing is one of the most effective welding techniques for aluminum alloys, and with the increasingly widespread application of aluminum alloys, its brazing technology is attracting more and more attention.

[0003] Aluminum-silicon-copper (ASi-Co) brazing filler metal powder, especially near-eutectic ASi-Co, has a relatively low melting point, good flowability, and high operability, making it widely used in furnace brazing of thin-walled complex aluminum alloy components. However, existing ASi-Co brazing filler metal powders are mostly prepared using gas atomization or water atomization, often requiring expensive atomization equipment. After atomization, additional drying and sieving processes are needed, resulting in a long and complex preparation process and high costs. In addition, some researchers have used mechanical crushing and grinding methods to prepare ASi-Co brazing filler metal powder, but this requires first crushing the aluminum-silicon-copper into small pieces, followed by grinding and sieving, a similarly complex process with low powder production efficiency. Furthermore, most existing crushing and grinding processes are carried out in an atmosphere with high oxygen content, resulting in high oxygen content in the brazing filler metal powder, which severely affects the performance of the brazed joints.

[0004] Chinese invention patent CN102935558B discloses a method for preparing self-brazing filler metal for welding aluminum-copper components. It uses vacuum atomization technology to prepare fine metal powder filler metal, but it requires a complete set of atomization equipment, resulting in high preparation costs. Moreover, the oxygen content of the filler metal powder is high, leading to poor brazing joint performance. To solve these problems, it is urgent to develop an integrated preparation device for aluminum-silicon-copper filler metal powder and a matching preparation method. Summary of the Invention

[0005] Therefore, it is necessary to address the existing problems in the preparation of current brazing filler metal powder by providing an integrated preparation method and apparatus for aluminum-silicon-copper brazing filler metal powder.

[0006] The primary objective of this invention is to provide an integrated preparation method for aluminum-silicon-copper brazing filler metal powder. This method is simple and can solve the problems of long production processes, low efficiency, and high costs associated with existing aluminum-silicon-copper brazing filler metal powder production. Moreover, the prepared brazing filler metal powder has low oxygen content and excellent brazing joint performance, showing promising prospects for industrial application.

[0007] The second objective of this invention is to provide an integrated preparation device for aluminum-silicon-copper solder powder. This device solves the problems of long process flow and high equipment cost of existing solder powder preparation equipment. This device does not require matching expensive atomization equipment, has low equipment cost, can realize the integrated preparation of aluminum-silicon-copper solder powder, and has higher powder preparation efficiency.

[0008] The third objective of this invention is to provide an aluminum-silicon-copper brazing filler powder with low oxygen content, which results in brazing joints with better performance.

[0009] The above objectives are achieved through the following technical solutions:

[0010] An integrated preparation method for aluminum-silicon-copper brazing filler metal powder includes the following steps:

[0011] (1) Melt and cast aluminum, silicon and copper metal raw materials to prepare metal blocks of a predetermined thickness;

[0012] (2) Apply liquid metal embrittlement agent to the surface of the metal block obtained in step (1) and let it stand for a preset time to make the metal block pulverize and become brittle.

[0013] (3) The metal block obtained in step (2) is transported into the grinding container and liquid nitrogen is continuously sprayed into the grinding container at a preset flow rate;

[0014] (4) Cut and grind the metal block in the grinding container to grind the metal block into semi-finished aluminum-silicon-copper brazing filler powder;

[0015] (5) Filter the brazing filler powder of the semi-finished product to obtain the finished aluminum-silicon-copper brazing filler powder.

[0016] In one embodiment, the aluminum-silicon-copper metal raw material in step (1) is composed of the following components by mass percentage: Si 5.1%, Cu 26.7%, Al 68.2%.

[0017] In one embodiment, the preset thickness of the metal block in step (1) is ≤15 mm.

[0018] In one embodiment, the liquid metal embrittler in step (2) is composed of the following components by mass percentage: 100% Ga or 75% Ga, 25% In or 68.5% Ga, 21.5% In, and 10% Sn, with a preset settling time of 2-5 minutes.

[0019] In one embodiment, the preset spray flow rate of liquid nitrogen in step (2) is 0.3 to 0.5 liters / hour.

[0020] In one embodiment, the liquid metal embrittlement agent in the finished aluminum-silicon-copper brazing filler powder in step (5) accounts for 0.5%-1% of the mass percentage of the finished aluminum-silicon-copper brazing filler powder.

[0021] An integrated preparation device for aluminum-silicon-copper brazing filler metal powder includes a grinding container, which contains several metal blocks of a predetermined thickness. A rotating shaft is provided inside the grinding container and can rotate around a first axis. A cutting tool is provided on the outer periphery of the rotating shaft and extends along the radial direction of the rotating shaft. The cutting edge of the cutting tool is serrated.

[0022] In one embodiment, a preset gap is left between the lower end face of the rotating shaft and the bottom of the grinding container. The rotating shaft is hollow inside and open at the lower end. An auger is rotatably installed inside the rotating shaft, and the diameter of the auger is adapted to the inner diameter of the rotating shaft.

[0023] In one embodiment, a guide pipe is provided at the upper part of the rotating shaft, the guide pipe is connected to the inside of the rotating shaft, and a three-pronged pipe is provided at the end of the guide pipe away from the rotating shaft. The first branch of the three-pronged pipe is connected to the inside of the grinding container, and the second branch of the three-pronged pipe is vertically downward for collecting finished aluminum-silicon-copper brazing powder. A filter plate is provided inside the three-pronged pipe and between the first branch and the second branch. The filter plate is inclined so that the semi-finished brazing powder can re-enter the grinding container along the filter plate for further grinding.

[0024] In one embodiment, the grinding container is further provided with a liquid nitrogen spray pipe, which is used to spray liquid nitrogen into the grinding container.

[0025] The beneficial effects of this invention are:

[0026] 1. The integrated method for producing aluminum-silicon-copper brazing filler metal powder used in this invention innovatively utilizes liquid metal to penetrate into the grain boundaries inside the metal block, causing initial embrittlement. Then, liquid nitrogen is sprayed to further embrittle it. Simultaneously, the blades inside the grinding device are activated for cutting and grinding, thereby obtaining the powder. This process is simple, has a short production flow, high powder production efficiency, and low cost.

[0027] 2. The integrated device for aluminum-silicon-copper brazing filler powder used in this invention is equipped with a liquid nitrogen spray pipe to spray liquid nitrogen into the grinding container to promote the brittle and powdered metal block, while forming an inert nitrogen atmosphere to protect the powder from oxidation. A rotating shaft and cutting blades are set up to cut and grind the metal block inside the grinding container. An auger is set up to transport the brittle and powdered aluminum-silicon-copper brazing filler powder inside the grinding container to a filter plate for filtration, thereby obtaining the finished aluminum-silicon-copper brazing filler powder. The entire production process does not require the use of atomization equipment. A single set of equipment can realize the crushing, grinding, deoxygenation and filtration of metal blocks. The equipment has low cost and high powder production efficiency.

[0028] 3. The finished aluminum-silicon-copper brazing filler powder obtained by this invention has a low oxygen content (0.038-0.077 w / %) and excellent brazing joint performance (38.7-42 MPa), and has broad application prospects in the field of brazing aluminum alloy components. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall structure of an integrated preparation device for aluminum-silicon-copper brazing filler metal powder according to the present invention.

[0030] Figure 2 This is a schematic cross-sectional view of an integrated preparation device for aluminum-silicon-copper brazing filler metal powder according to the present invention.

[0031] Figure 3 for Figure 2 Enlarged view of the structure at point A in the middle;

[0032] Figure 4 This is a half-sectional perspective view of an integrated preparation device for aluminum-silicon-copper brazing filler metal powder according to the present invention.

[0033] Figure 5 This is a schematic diagram of the cutting tool in the integrated preparation device for aluminum-silicon-copper brazing filler metal powder of the present invention;

[0034] Figure 6 The metallographic structure diagrams show the weld joints of the aluminum-silicon-copper brazing filler powder prepared in this invention (right figure) and existing brazing filler powder (left figure).

[0035] in:

[0036] 100. Grinding container; 110. Exhaust port; 210. Rotating shaft; 220. Cutting tool; 221. Wear-resistant inclined surface; 230. Screw auger; 240. Feed guide pipe; 250. Three-way branch pipe; 251. First branch pipe opening; 252. Second branch pipe opening; 260. Filter plate; 300. Liquid nitrogen spray pipe; 310. Hydraulic tank; 410. Drive motor; 420. First pulley; 430. Second pulley; 500. Fixing sleeve; 610. External gear ring; 620. Central gear; 630. Connecting frame; 640. Intermediate gear; 700. Support. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0038] The serial numbers assigned to components in this document, such as "first," "second," etc., are merely used to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages). In the description of this invention, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention.

[0039] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0040] like Figures 1-6 As shown, an integrated preparation device for aluminum-silicon-copper solder powder includes a grinding container 100, which contains several aluminum-silicon-copper metal blocks of a predetermined thickness. A rotating shaft 210 is provided inside the grinding container 100, and the rotating shaft 210 can rotate around a first axis, which is the axis of the rotating shaft 210. Specifically, a drive motor 410 is provided outside the grinding container 100. The output shaft of the drive motor 410 is fixedly connected to a first pulley 420, and a second pulley 430 is fixedly connected to the outer periphery of the rotating shaft 210. The first pulley 420 and the second pulley 430 are connected by a belt, so that the drive motor 410 outputs torque to drive the rotating shaft 210 to rotate. A cutting tool 220 is provided on the outer periphery of the rotating shaft 210, and the cutting tool 220 extends in the radial direction of the rotating shaft 210. The cutting edge of the cutting tool 220 is serrated.

[0041] In use, the operator adds aluminum-silicon-copper metal blocks coated with liquid metal embrittlement agent into the grinding container 100, starts the drive motor 410, and drives the rotating shaft 210 to rotate through the belt drive of the first pulley 420 and the second pulley 430. The rotating shaft 210 drives the cutting tool 220 to rotate. The cutting tool 220 follows the rotation of the rotating shaft 210 to cut and grind the aluminum-silicon-copper metal blocks inside the grinding container 100, so that the particle size of the aluminum-silicon-copper metal blocks becomes smaller, and finally the aluminum-silicon-copper metal blocks are ground into aluminum-silicon-copper brazing filler metal powder with a qualified particle size.

[0042] It should be further explained that the cutting edge of the cutting tool 220 is serrated. This allows the aluminum-silicon-copper metal block to slide relative to the cutting tool 220 in the radial direction of the rotating shaft 210, and the serrations of the cutting edge of the cutting tool 220 to exert greater pressure on the aluminum-silicon-copper metal block, thus promoting the pulverization of the aluminum-silicon-copper metal block.

[0043] It should also be noted that the axis of the rotating shaft 210 should be perpendicular to the bottom surface of the grinding container 100, so that when the cutting tool 220 cuts and grinds the aluminum-silicon-copper metal block inside the grinding container 100, the cutting tool 220 is subjected to uniform force at all points.

[0044] In a further embodiment, such as Figure 2 and Figure 4 As shown, a preset distance is left between the lower end face of the rotating shaft 210 and the bottom of the grinding container 100. The rotating shaft 210 is hollow inside and open at the lower end. An auger spiral 230 is rotatably installed inside the rotating shaft 210. The diameter of the auger spiral 230 is adapted to the inner diameter of the rotating shaft 210. To realize the rotation of the auger spiral 230, a central gear 620 is fixedly connected to the upper end of the auger spiral 230, and an external gear ring 610 is fixedly connected to the upper end of the rotating shaft 210. An intermediate gear 640 meshes between the external gear ring 610 and the central gear 620, thereby driving the external gear ring 610 to rotate through the rotating shaft 210. When the external gear ring 610 drives the intermediate gear 640 to rotate, the intermediate gear 640 drives the central gear 620 to rotate, and the central gear 620 drives the auger spiral 230 to rotate, thereby driving the auger spiral 230 to rotate.

[0045] Additionally, to support the intermediate gear 640, a fixing sleeve 500 is fixedly connected to the top of the grinding container 100, and a connecting frame 630 is fixedly connected to the lower end of the fixing sleeve 500. The intermediate gear 640 is rotatably mounted on the connecting frame 630. Furthermore, to guide and support the upper end of the auger spiral 230, a limiting hole can be opened on the lower end face of the connecting frame 630, so that the upper part of the auger spiral 230 is rotatably connected within the limiting hole.

[0046] It should also be added that, such as Figure 5As shown, a wear-resistant inclined surface 221 is provided on the upper surface of the cutting tool 220. The material of the wear-resistant inclined surface 221 is hard wear-resistant alloy. During the rotation of the cutting tool 220 driven by the rotating shaft 210, under the guidance of the inclined surface of the wear-resistant inclined surface 221, the aluminum-silicon-copper metal block can roll along the guide inclined surface of the wear-resistant inclined surface 221 in a direction away from the center of the rotating shaft 210. During the rolling process, the aluminum-silicon-copper metal block and the wear-resistant inclined surface 221 rub against each other, so that the aluminum-silicon-copper metal block is ground by the wear-resistant inclined surface 221 and the particle size gradually becomes smaller.

[0047] In use, the operator starts the drive motor 410, which drives the auger spiral 230 and the rotating shaft 210 to rotate at the same angular velocity. The rotating shaft 210 drives the cutting tool 220 to rotate and cut and grind the aluminum-silicon-copper metal block. The rotating shaft 210 drives the auger spiral 230 to rotate, so that the semi-finished aluminum-silicon-copper brazing powder enters the rotating shaft 210. Driven by the spiral blades of the auger spiral 230, the semi-finished aluminum-silicon-copper brazing powder overcomes friction and rises in a spiral trajectory, thereby conveying the semi-finished aluminum-silicon-copper brazing powder to the upper part of the rotating shaft 210, so that the semi-finished aluminum-silicon-copper brazing powder can be discharged from the upper part of the rotating shaft 210 to the outside of the grinding container 100.

[0048] It should be noted that the number of cutting tools 220 should be two or more, and the rotation of the shaft 210 should enable the cutting edge of the cutting tool 220 to actively face the aluminum-silicon-copper metal block, thereby applying force to the aluminum-silicon-copper metal block.

[0049] In a further embodiment, such as Figure 2 As shown, a liquid nitrogen spray pipe 300 is also provided on the grinding container 100. The liquid nitrogen spray pipe 300 is used to spray liquid nitrogen into the grinding container 100. Specifically, the spray head of the liquid nitrogen spray pipe 300 is located inside the grinding container 100 and faces the bottom of the grinding container 100. A hydraulic tank 310 is provided outside the grinding container 100. The discharge valve of the hydraulic tank 310 is connected to the liquid nitrogen spray pipe 300, so that the liquid nitrogen inside the hydraulic tank 310 can be sprayed to the bottom of the grinding container 100 through the liquid nitrogen spray pipe 300.

[0050] It should be added that the grinding container 100 is made of stainless steel, and the top of the grinding container 100 also needs to be provided with an exhaust port 110 so that the air inside the grinding container 100 can be discharged when nitrogen is sprayed into the grinding container 100.

[0051] In a further embodiment, such as Figure 2As shown, specifically, a guide tube 240 is provided on the upper part of the rotating shaft 210. The guide tube 240 is connected to the interior of the rotating shaft 210. A three-way tube 250 is provided at the end of the guide tube 240 away from the rotating shaft 210. The end of the guide tube 240 connected to the rotating shaft 210 is higher and the other end is lower, so that the semi-finished brazing powder entering the guide tube 240 can slide towards the end close to the three-way tube 250 under the action of gravity. The first branch port 251 of the three-way tube 250 is connected to the interior of the grinding container 100. The second branch port 252 of the three-way tube 250 is vertically downward. A filter plate 260 is provided inside the three-way tube 250 and between the first branch port 251 and the second branch port 252. The filter plate 260 has a number of filter holes. The filter plate 260 is inclined so that the semi-finished aluminum-silicon-copper brazing powder can enter the interior of the grinding container 100 along the filter plate 260.

[0052] When the semi-finished aluminum-silicon-copper brazing filler powder moves from the feed pipe 240 into the three-way pipe 250, it falls onto the filter plate 260. At this time, aluminum-silicon-copper brazing filler powder with a particle size larger than the pore size of the filter plate 260 cannot pass through the filter plate 260 and can only roll down from the first branch pipe opening 251 along the inclined surface of the filter plate 260 into the grinding container 100. Meanwhile, aluminum-silicon-copper brazing filler powder with a particle size smaller than the pore size of the filter plate 260 passes through the filter plate 260 and is discharged outward from the second branch pipe opening 252. At this time, the finished aluminum-silicon-copper brazing filler powder is obtained.

[0053] In a further embodiment, a support 700 is provided at the bottom of the grinding container 100, which is used to support the grinding container 100.

[0054] An integrated preparation method for aluminum-silicon-copper brazing filler metal powder includes the following steps:

[0055] (1) Melt and cast aluminum, silicon and copper metal raw materials to prepare metal blocks of a predetermined thickness;

[0056] (2) Apply liquid metal embrittlement agent to the surface of the metal block obtained in step (1) and let it stand for a preset time to make the metal block pulverize and become brittle. In order to make the degree of embrittlement of the metal blocks basically uniform, the liquid metal embrittlement agent needs to be evenly applied to the surface of the metal block.

[0057] (3) The metal block obtained in step (2) is transported into the grinding container and liquid nitrogen is continuously sprayed into the grinding container at a preset flow rate. The grinding container is a closed container. Spraying liquid nitrogen into the closed grinding container can, on the one hand, exhaust the air inside the grinding container and make the grinding container 100 obtain an inert atmosphere to ensure that the metal block is not oxidized. On the other hand, the sprayed liquid nitrogen can further promote the embrittlement of the aluminum-silicon-copper metal block.

[0058] (4) Cut and grind the metal block in the grinding container to grind the metal block into semi-finished aluminum-silicon-copper brazing filler powder;

[0059] (5) Filter the brazing filler powder of the semi-finished product to obtain the finished aluminum-silicon-copper brazing filler powder.

[0060] An integrated preparation method for aluminum-silicon-copper brazing filler metal powder, specifically: First, a liquid metal embrittlement agent is uniformly brushed onto the surface of the metal block obtained in step (1). The liquid metal embrittlement agent gradually penetrates into the metal grain boundaries of the aluminum-silicon-copper metal block, causing the aluminum-silicon-copper metal block to become brittle and powdery. Then, the brittle and powdery metal block is placed in a grinding container 100, and liquid nitrogen is continuously sprayed into the grinding container 100 at a preset flow rate. Then, the metal block in the grinding container 100 is cut and ground, so that the metal block is ground into a semi-finished aluminum-silicon-copper brazing filler metal powder. During the grinding process, the sprayed liquid nitrogen can, on the one hand, expel the air inside the grinding container, giving the grinding container 100 an inert atmosphere and preventing the aluminum-silicon-copper metal block from being oxidized during the cutting and grinding process by the cutting tool 220. On the other hand, the sprayed liquid nitrogen can also cool the metal block and further embrittle the aluminum-silicon-copper metal block, thereby significantly improving the grinding efficiency. After the aluminum-silicon-copper metal block is ground into semi-finished aluminum-silicon-copper brazing filler powder, the semi-finished brazing filler powder needs to be filtered to obtain the finished aluminum-silicon-copper brazing filler powder.

[0061] It should be noted that the semi-finished aluminum-silicon-copper brazing filler powder refers to the brazing filler powder that meets the particle size standard (finished brazing filler powder) and the brazing filler powder that does not meet the particle size standard. Therefore, the brazing filler powder of this finished product needs to be filtered to remove the brazing filler powder that does not meet the particle size standard. What remains is the brazing filler powder that meets the particle size standard, that is, the finished brazing filler powder.

[0062] It should be added that the aluminum-silicon-copper metal raw material in step (1) is composed of the following components by mass percentage: Si 5.1%, Cu 26.7%, Al 68.2%, which is a ternary eutectic aluminum-silicon-copper metal raw material, which can better meet the welding requirements of thin-walled aluminum alloys.

[0063] Considering the improved joint strength of thin-walled aluminum alloy components, preferably, the aluminum-silicon-copper metal raw material is composed of the following components by mass percentage: Si 5.1%, Cu 26.7%, with the balance being Al; or Al 88%, Si 12%; or Al 80%, Si 20%. More preferably, the aluminum-silicon-copper metal raw material is composed of the following components by mass percentage: Si 5.1%, Cu 26.7%, with the balance being Al. The aluminum-silicon-copper raw material with an Al-5.1Si-26.7Cu composition is a ternary eutectic aluminum-silicon-copper metal raw material, which better meets the welding requirements of thin-walled aluminum alloys.

[0064] It should be added that the preset thickness of the metal block in step (1) is ≤15 mm. This setting is conducive to obtaining aluminum-silicon-copper metal powder with the required particle size.

[0065] It should be added that the liquid metal embrittlement in step (2) is composed of the following components by mass percentage: Ga 100% (gallium accounts for 100%) or Ga 75%, In 25% (gallium accounts for 75%, indium accounts for 25%) or Ga 68.5%, In 21.5%, Sn 10% (gallium accounts for 68.5%, indium accounts for 21.5%, tin accounts for 10%), and the preset standing time is 2-5 minutes.

[0066] The liquid metal embrittler provided in this embodiment has a high surface tension, which allows it to penetrate into the metal grain boundaries of the aluminum-silicon-copper metal block in a short time. Therefore, it only needs to be applied at room temperature and left to stand for 2-5 minutes to wet the solid metal. The liquid metal embrittler transforms from liquid to solid, causing the volume expansion rate of the aluminum-silicon-copper metal block to be as high as 3% or more. This makes it easy to break the internal grain boundaries of the metal, disintegrate the crystal structure of the metal from the inside, reduce the bonding force between solid metal atoms, and destroy the original metal bonds, thereby making the aluminum-silicon-copper metal block brittle and powdery, effectively improving the subsequent grinding effect.

[0067] It should be added that the preset spray flow rate of liquid nitrogen is 0.3 to 0.5 liters per hour. This setting is to control the grinding speed of the aluminum, silicon and copper metal blocks, so as to obtain more brazing filler metal powder with the required particle size.

[0068] Method 1

[0069] Based on the above preparation method, the present invention provides a preferred embodiment in which the method for preparing aluminum-silicon-copper solder powder provided by the present invention includes the following steps:

[0070] (1) The aluminum-silicon-copper metal raw material with Al-5.1Si-26.7Cu composition is smelted and cast to prepare a metal block with a preset thickness of 10 mm;

[0071] (2) Apply liquid metal embrittlement agent to the surface of the metal block obtained in step (1). The liquid metal embrittlement agent is Ga. Let it stand for 5 minutes to make the metal block pulverize and become brittle. In order to make the degree of embrittlement of the metal block basically uniform, the liquid metal embrittlement agent needs to be evenly applied to the surface of the metal block.

[0072] (3) The metal block obtained in step (2) is transported into the grinding container and liquid nitrogen is continuously sprayed into the grinding container at 0.4 liters / hour. The grinding container is a closed container. Spraying liquid nitrogen into the closed grinding container can, on the one hand, remove the air inside the grinding container and obtain an inert atmosphere to ensure that the metal block is not oxidized. On the other hand, the sprayed liquid nitrogen can further promote the embrittlement of the aluminum-silicon-copper metal block.

[0073] (4) Cut and grind the metal block in the grinding container so that the rotation speed of the rotating shaft 210 is 150 rpm and the rotation time is 40 minutes, so that the metal block is ground into semi-finished aluminum-silicon-copper brazing filler powder.

[0074] (5) Filter the semi-finished brazing powder. The filter plate 260 has a pore size of 600-800 mesh to obtain finished aluminum-silicon-copper brazing powder.

[0075] The aluminum-silicon-copper brazing filler powder in this embodiment was prepared using method 1 described above.

[0076] Method 2

[0077] Based on the above method, the present invention provides another preferred embodiment, in which the method for preparing aluminum-silicon-copper brazing filler metal powder provided by the present invention includes the following steps:

[0078] (1) The aluminum-silicon-copper metal raw material with Al-5.1Si-26.7Cu composition is smelted and cast to prepare a metal block with a preset thickness of 10 mm;

[0079] (2) The surface of the metal block obtained in step (1) is coated with liquid metal embrittlement agent, which is 5Ga-25In, and left to stand for 4 minutes to make the metal block pulverize and become brittle. In order to make the degree of embrittlement of the metal block basically uniform, the liquid metal embrittlement agent needs to be evenly coated on the surface of the metal block.

[0080] (3) The metal block obtained in step (2) is transported into the grinding container and liquid nitrogen is continuously sprayed into the grinding container at 0.5 liters / hour. The grinding container is a closed container. Spraying liquid nitrogen into the closed grinding container can, on the one hand, remove the air inside the grinding container and obtain an inert atmosphere to ensure that the metal block is not oxidized. On the other hand, the sprayed liquid nitrogen can further promote the embrittlement of the aluminum-silicon-copper metal block.

[0081] (4) Cut and grind the metal block in the grinding container so that the rotation speed of the rotating shaft 210 is 130 rpm and the rotation time is 30 minutes, so that the metal block is ground into semi-finished aluminum-silicon-copper brazing filler powder.

[0082] (5) Filter the semi-finished brazing filler powder. The filter plate 260 has a pore size of 500-600 mesh to obtain finished aluminum-silicon-copper brazing filler powder.

[0083] The aluminum-silicon-copper brazing filler powder in this embodiment was prepared using method 2 described above.

[0084] Method 3

[0085] Based on the above method, the present invention provides a preferred embodiment in which the method for preparing aluminum-silicon-copper brazing filler metal powder provided by the present invention includes the following steps:

[0086] (1) The aluminum-silicon-copper metal raw material with Al-5.1Si-26.7Cu composition is smelted and cast to prepare a metal block with a preset thickness of 10 mm;

[0087] (2) The surface of the metal block obtained in step (1) is coated with liquid metal embrittlement agent, which is 68.5Ga-21.5In-10Sn, and left to stand for 3 minutes to make the metal block pulverize and become brittle. In order to make the degree of embrittlement of the metal block basically uniform, the liquid metal embrittlement agent needs to be evenly coated on the surface of the metal block.

[0088] (3) The metal block obtained in step (2) is transported into the grinding container and liquid nitrogen is continuously sprayed into the grinding container at 0.3 liters / hour. The grinding container is a closed container. Spraying liquid nitrogen into the closed grinding container can, on the one hand, remove the air inside the grinding container and obtain an inert atmosphere to ensure that the metal block is not oxidized. On the other hand, the sprayed liquid nitrogen can further promote the embrittlement of the aluminum-silicon-copper metal block.

[0089] (4) Cut and grind the metal block in the grinding container so that the rotation speed of the rotating shaft 210 is 120 rpm and the rotation time is 25 minutes, so that the metal block is ground into semi-finished aluminum-silicon-copper brazing filler powder.

[0090] (5) Filter the semi-finished brazing powder. The filter plate 260 has a pore size of 400-500 mesh to obtain finished aluminum-silicon-copper brazing powder.

[0091] The aluminum-silicon-copper brazing filler powder in this embodiment was prepared using method 3 described above.

[0092] Method 4

[0093] Based on the above method, the present invention provides a preferred embodiment in which the method for preparing aluminum-silicon-copper brazing filler metal powder provided by the present invention includes the following steps:

[0094] (1) The aluminum-silicon-copper metal raw material with Al-5.1Si-26.7Cu composition is smelted and cast to prepare a metal block with a preset thickness of 10 mm;

[0095] (2) Apply liquid metal embrittlement agent to the surface of the metal block obtained in step (1). The liquid metal embrittlement agent is Ga. Let it stand for 2 minutes to make the metal block pulverize and become brittle. In order to make the degree of embrittlement of the metal block basically uniform, the liquid metal embrittlement agent needs to be evenly applied to the surface of the metal block.

[0096] (3) The metal block obtained in step (2) is transported into the grinding container and liquid nitrogen is continuously sprayed into the grinding container at 0.4 liters / hour. The grinding container is a closed container. Spraying liquid nitrogen into the closed grinding container can, on the one hand, remove the air inside the grinding container and obtain an inert atmosphere to ensure that the metal block is not oxidized. On the other hand, the sprayed liquid nitrogen can further promote the embrittlement of the aluminum-silicon-copper metal block.

[0097] (4) Cut and grind the metal block in the grinding container so that the rotation speed of the rotating shaft 210 is 100 rpm and the rotation time is 20 minutes, so that the metal block is ground into semi-finished aluminum-silicon-copper brazing filler powder.

[0098] (5) Filter the semi-finished brazing powder. The filter plate 260 has a pore size of 300-400 mesh to obtain finished aluminum-silicon-copper brazing powder.

[0099] The aluminum-silicon-copper brazing filler powder in this embodiment was prepared using method 4 described above.

[0100] Method 5

[0101] Based on the above method, the present invention provides a preferred embodiment in which the method for preparing aluminum-silicon-copper brazing filler metal powder provided by the present invention includes the following steps:

[0102] (1) The aluminum-silicon-copper metal raw material with Al-5.1Si-26.7Cu composition is smelted and cast to prepare a metal block with a preset thickness of 10 mm;

[0103] (2) Apply liquid metal embrittlement agent to the surface of the metal block obtained in step (1). The liquid metal embrittlement agent is Ga. Let it stand for 2 minutes to make the metal block pulverize and become brittle. In order to make the degree of embrittlement of the metal block basically uniform, the liquid metal embrittlement agent needs to be evenly applied to the surface of the metal block.

[0104] (3) The metal block obtained in step (2) is transported into the grinding container and liquid nitrogen is continuously sprayed into the grinding container at 0.4 liters / hour. The grinding container is a closed container. Spraying liquid nitrogen into the closed grinding container can, on the one hand, remove the air inside the grinding container and obtain an inert atmosphere to ensure that the metal block is not oxidized. On the other hand, the sprayed liquid nitrogen can further promote the embrittlement of the aluminum-silicon-copper metal block.

[0105] (4) Cut and grind the metal block in the grinding container so that the rotation speed of the rotating shaft 210 is 80 rpm and the rotation time is 10 minutes, so that the metal block is ground into semi-finished aluminum-silicon-copper brazing filler powder.

[0106] (5) Filter the brazing filler powder of the semi-finished product. The pore size of the filter plate 260 is 200-300 mesh, which is the same as that of the liquid nitrogen spray pipe, to obtain the finished aluminum-silicon-copper brazing filler powder.

[0107] The aluminum-silicon-copper brazing filler powder in this embodiment was prepared using method 5 described above.

[0108] The oxygen content in the aluminum-silicon-copper brazing filler powder prepared by methods 1-5 and by existing methods was tested using a nitrogen-hydrogen-oxygen combined analyzer. Simultaneously, each brazing filler powder sample was used for furnace brazing of 3003 aluminum alloy and copper. The shear strength of the joint was tested after brazing, with reference to standard GB / T11363. The aluminum-silicon-copper brazing filler powder obtained by the existing method has a composition of 68.2% Al, 5.1% Si, and 26.7% Cu, i.e., Al-5.1Si-26.7Cu. It is prepared using a mechanical crushing, grinding, and sieving method. The specific preparation process is as follows: large pieces of metal are first crushed into small pieces, then ball-milled, and sieved to obtain powder with a particle size of 200-300 mesh.

[0109] The test results for oxygen content and shear strength are shown in Table 1.

[0110] Table 1. Comparison of oxygen content and joint shear strength between the brazing filler metal powders prepared by methods 1-5 and existing brazing filler metal powders.

[0111] The brazing filler metal powder prepared by method 1 0.077 38.7 The brazing filler powder prepared by method 2 0.063 39.5 The brazing filler metal powder prepared by method 3 0.051 40.8 The brazing filler metal powder prepared by method 4 0.042 41.5 The brazing filler metal powder prepared by method 5 0.038 42 Solder powder produced by existing technology 0.13 30.5

[0112] As shown in Table 1, among the five types of aluminum-silicon-copper brazing filler metal powders prepared by methods 1-5 of this invention, the oxygen content decreases and the joint shear strength increases as the particle size of the brazing filler metal powder becomes coarser. Compared with the 200-300 mesh aluminum-silicon-copper brazing filler metal powder prepared by existing mechanical crushing, grinding, and sieving methods, the aluminum-silicon-copper brazing filler metal powder obtained by method 5 of this invention shows the largest reduction in oxygen content, decreasing from 0.13% to 0.038%. Compared with existing brazing filler metal powders, the brazing filler metal powder obtained by method 5 of this invention exhibits significantly improved weld joint shear strength, reaching 38.7-42 MPa, which is far superior to existing aluminum-silicon-copper brazing filler metal powders.

[0113] Further scanning electron microscopy was used to analyze the microstructure of the brazing filler metal powder prepared by method 5 and the welded joints of aluminum-silicon-copper brazing filler metal powders in the prior art. The results are as follows: Figure 6 As shown.

[0114] Depend on Figure 6 It can be seen that there are many slag pores in the existing brazing filler metal powder welded joints. Figure 6(Left figure). The slag porosity in the aluminum-silicon-copper brazing filler powder joint obtained by method 5 of this invention is significantly reduced ( Figure 6 (See right figure). This also confirms that the aluminum-silicon-copper brazing filler powder prepared by this invention has fewer inclusions, higher purity, higher brazing joint strength, and better overall performance.

[0115] Comparative analysis revealed that traditional crushing, grinding, and sieving methods fail to embrittle and pulverize the brazing filler metal blocks. The metal must first be crushed into metal fragments in a metal crusher, where the hard metal easily breaks the cutting blades. During the cutting and grinding process, the lack of protection causes the powder to oxidize due to frictional heat. Finally, sieving is required to obtain brazing filler powder. This method requires approximately 6 hours for two workers to prepare 5 kg of brazing filler powder. In contrast, the brazing filler metal blocks in this invention are pre-embrittled and pulverized, and then mechanically crushed and ground under liquid nitrogen protection for further embrittlement. Simultaneous filtration and collection, with all processes completed on a single device, allow for the preparation of 5 kg of brazing filler powder in approximately 3 hours. This invention achieves twice the powder-making efficiency of the traditional method. Therefore, the preparation device and method of this invention effectively improve the powder-making efficiency of aluminum-silicon-copper brazing filler powder and are more suitable for large-scale industrial production applications.

[0116] In summary, the aluminum-silicon-copper brazing filler powder and its integrated preparation method and apparatus provided by this invention simultaneously realize the functions of crushing, grinding, filtering, deoxygenating and collecting aluminum-silicon-copper brazing filler powder in one set of equipment, with high powder production efficiency; and the obtained brazing filler powder has low oxygen content and excellent brazing joint performance, and has broad application prospects in the preparation of high-quality aluminum-silicon-copper brazing filler powder and the brazing of aluminum alloy components.

[0117] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0118] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. An integrated preparation method for aluminum-silicon-copper brazing filler metal powder, characterized in that, Includes the following steps: (1) Melt and cast aluminum, silicon and copper metal raw materials to prepare metal blocks of a predetermined thickness; (2) Apply liquid metal embrittlement agent to the surface of the metal block obtained in step (1) and let it stand for a preset time to make the metal block pulverize and become brittle; (3) The metal block obtained in step (2) is transported into the grinding container and liquid nitrogen is continuously sprayed into the grinding container at a preset flow rate; (4) Cut and grind the metal block in the grinding container to grind the metal block into semi-finished aluminum-silicon-copper brazing filler powder; (5) Filter the brazing filler powder of the semi-finished product to obtain the finished aluminum-silicon-copper brazing filler powder.

2. The integrated preparation method of aluminum-silicon-copper brazing filler metal powder according to claim 1, characterized in that, The aluminum-silicon-copper metal raw materials mentioned in step (1) are composed of the following components by mass percentage: Si 5.1%, Cu 26.7%, Al 68.2%.

3. The integrated preparation method of aluminum-silicon-copper brazing filler metal powder according to claim 1, characterized in that, The preset thickness of the metal block in step (1) is ≤15 mm.

4. The integrated preparation method of aluminum-silicon-copper brazing filler metal powder according to claim 1, characterized in that, The liquid metal embrittlement agent described in step (2) consists of the following components by mass percentage: Ga 100%; or Ga 75% and In 25%; or Ga 68.5% and In 21.5% and Sn 10%; The preset set time is 2-5 minutes.

5. The integrated preparation method of aluminum-silicon-copper brazing filler metal powder according to claim 1, characterized in that, The preset spray flow rate of liquid nitrogen in step (2) is 0.3-0.5 liters / hour.

6. An aluminum-silicon-copper brazing filler powder, prepared using the integrated preparation method of aluminum-silicon-copper brazing filler powder according to any one of claims 1-5, characterized in that, In step (5), the liquid metal embrittlement agent in the finished aluminum-silicon-copper brazing filler powder accounts for 0.5%-1% of the mass percentage of the finished aluminum-silicon-copper brazing filler powder.

7. An integrated preparation apparatus for aluminum-silicon-copper brazing filler metal powder, characterized in that, The device includes a grinding container containing several metal blocks of a predetermined thickness. A rotating shaft is installed inside the grinding container, capable of rotating around a first axis. A cutting tool is mounted on the outer circumference of the rotating shaft, extending radially along the shaft, and the cutting edge of the tool is serrated. A predetermined distance is maintained between the lower end of the rotating shaft and the bottom of the grinding container. The rotating shaft is hollow with an opening at its lower end. A auger spiral is rotatably mounted inside the rotating shaft, its diameter matching the inner diameter of the shaft. A guide pipe is installed at the upper part of the rotating shaft, connecting to the interior of the shaft. A three-pronged pipe is installed at the end of the guide pipe furthest from the rotating shaft. The first branch of the three-pronged pipe connects to the interior of the grinding container, and the second branch faces downwards. A filter plate is installed inside the three-pronged pipe, between the first and second branch openings, at an angle to allow the semi-finished brazing filler metal powder to enter the interior of the grinding container along the filter plate.

8. The integrated preparation apparatus for aluminum-silicon-copper brazing filler metal powder according to claim 7, characterized in that, The grinding container is also equipped with a liquid nitrogen spray pipe, which is used to spray liquid nitrogen into the grinding container.

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