Preparation mold and method of porous hollow metal sphere

Abstract

The application discloses a kind of preparation mould of porous hollow metal ball, including upper die punch with upper concave hemisphere and lower die punch with lower concave hemisphere, and upper half screw rod and lower half screw rod are arranged on upper die punch and lower die punch, and bolt hole is opened.Therefore, the application also discloses a kind of preparation method of porous hollow metal ball, metal powder feed is loaded into mould after heating, then start rotating, finally high temperature heat treatment is carried out, and porous hollow metal ball is obtained.The application is combined by upper die punch and lower die punch with multiple concave hemispheres on the surface, and multiple porous hollow metal balls are prepared at a time, with high production efficiency, low preparation cost, the size and wall thickness of the prepared porous hollow metal ball are regulated according to application environment, and the surface of the porous hollow metal ball is smooth, with metallic luster, high sphericity, which can meet the demand of heat insulation, sound insulation and other materials and components in automobile, aerospace, steel metallurgy, nuclear industry and other fields.

Description

Technical Field

[0001] This invention belongs to the field of porous metal material preparation technology, specifically relating to a mold and preparation method for porous hollow metal spheres. Background Technology

[0002] Porous metallic materials are a type of structural and functional integrated material composed of a rigid framework and its internal pores. They possess the characteristics of metallic materials as well as properties such as low density, high specific surface area, high specific strength, high permeability, excellent sound absorption and noise reduction, and efficient heat exchange. They have been applied in aerospace, steel metallurgy, petrochemical, transportation, biomedicine, electronic information and other fields, and are an indispensable key supporting material in modern high-tech fields.

[0003] Currently, the main methods for preparing porous metal materials include pressureless forming, compression forming, space-occupying forming, slurry forming, foaming, and additive manufacturing. However, these methods suffer from problems such as uneven pore distribution and poor pore size controllability, making it difficult to meet the urgent needs of modern high-tech fields for high-performance porous metal materials. Based on this problem, it is envisioned that if a type of porous hollow metal sphere with controllable pore size and porosity could be prepared, then the preparation of high-performance porous metal materials using these spheres would become a reality. Porous hollow metal spheres possess characteristics such as regular shape, stable structure, and controllable macroscopic dimensions. The compressive strength, energy absorption performance, sound insulation performance, and thermal insulation performance of porous metal materials prepared from them can be optimized and adjusted according to the usage environment. Therefore, porous hollow metal spheres are a key raw material for preparing porous metal materials with precisely controllable service performance.

[0004] After years of research, scientists have developed several methods for preparing porous hollow metal spheres, such as the template method, displacement reaction method, coaxial jet forming method, and 3D printing technology. The template method uses polymer spherical microparticles or particle precursors as templates. A layer of metal powder of a certain thickness is coated onto the template core through coating, adhesion, adsorption, precipitation reaction, sol-gel interaction, etc., forming a core-shell structure. Then, porous hollow metal spheres are obtained by heat treatment or solvent dissolution of the template. Domestic and foreign scholars have published numerous patents and papers on the preparation of porous hollow metal spheres using the template method, involving material systems including titanium alloys and stainless steel. However, the template is prone to contaminating the metal powder during removal, and the sphere shell is not dense and has poor thickness controllability, resulting in low mechanical properties of the porous hollow metal spheres. The displacement reaction method involves immersing spherical iron particles in a copper sulfate solution. Iron and copper undergo a displacement reaction, with copper deposited on the surface of the iron particles, while the iron particles gradually dissolve to eventually form porous copper spheres. However, this method has limited applicability to certain material systems. Coaxial jetting combines coaxial jetting equipment with gas injection equipment to atomize and disperse metal slurry, followed by high-temperature heat treatment and post-treatment to produce porous hollow metal spheres. During the high-temperature heat treatment process, the binder can contaminate the metal powder; furthermore, the macroscopic dimensions of the porous hollow metal spheres are difficult to control precisely. 3D printing technology can directly form large-sized porous hollow metal spheres, but it is difficult to produce porous hollow metal spheres smaller than 5mm, and the surface roughness of the spheres is relatively large, while the printing cost is high.

[0005] Based on the shortcomings of the above methods, there is a need to provide a mold and preparation method for porous hollow metal spheres. Summary of the Invention

[0006] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a mold for preparing porous hollow metal spheres. This mold uses an upper and lower die punch with multiple concave hemispheres distributed on their surfaces to close together, producing multiple porous hollow metal spheres at once. This results in high production efficiency and low production cost. By controlling the diameter of the multiple concave hemispheres on the lower die punch and making the diameters vary in a gradient, porous hollow metal spheres with different diameters can be produced in one pass, further improving production efficiency.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a mold for preparing porous hollow metal spheres, characterized in that the mold includes an upper die punch and a lower die punch, the lower surface of the upper die punch is provided with a plurality of uniformly distributed upper concave hemispheres, the upper surface of the lower die punch is provided with a plurality of lower concave hemispheres corresponding to the upper concave hemispheres, the sides of the upper die punch and the lower die punch are respectively provided with upper half screws and lower half screws, and bolt holes are opened on both the upper die punch and the lower die punch.

[0008] The above-mentioned mold for preparing a porous hollow metal sphere is characterized in that the diameter of the concave hemisphere is 0.5mm to 5.0mm, and an annular boss is provided on the outer edge of the concave hemisphere. The height of the annular boss is 1.0mm to 1.5mm and the width is 1.5mm to 2.0mm; an annular recess corresponding to the annular boss is provided on the outer edge of the upper concave hemisphere.

[0009] The above-mentioned mold for preparing a porous hollow metal sphere is characterized in that the distance between adjacent concave hemispheres punched on the upper mold is 3mm to 4mm.

[0010] The above-mentioned mold for preparing a porous hollow metal sphere is characterized in that the surface roughness of the upper and lower die punches does not exceed 1.6 μm.

[0011] In addition, the present invention also provides a method for preparing porous hollow metal spheres, characterized in that the method includes the following steps:

[0012] Step 1: Mix the metal powder and binder to obtain the metal powder feed;

[0013] Step 2: Place the metal powder obtained in Step 1 into the concave hemisphere of the lower die punch to obtain the loading lower die punch;

[0014] Step 3: Combine the lower and upper punches obtained in Step 2 and fix them with bolts to obtain the loading mold;

[0015] Step 4: Heat the loading mold obtained in Step 3 to obtain a heated loading mold;

[0016] Step 5: Fix the upper and lower screws of the heating and loading mold obtained in Step 4 to the rotary table. Then start the rotary table to make the heating and loading mold rotate with the upper and lower screws as the axis. After rotating for 2 to 3 minutes, turn off the rotary table to obtain the rotated loading mold.

[0017] Step 6: After the rotating loading mold obtained in Step 5 has cooled naturally to room temperature, open it to obtain a porous hollow metal sphere green blank.

[0018] Step 7: Perform high-temperature heat treatment on the porous hollow metal sphere green blank obtained in Step 6 to obtain porous hollow metal spheres.

[0019] This invention involves mixing metal powder and a binder, then loading the mixture into the concave hemisphere of a lower die punch. The lower and upper die punches are combined and secured with bolts. Heating softens the metal powder feed, giving it a certain degree of fluidity. A rotary table is activated, causing the heated loading die to rotate around the upper and lower screws. This allows the softened metal powder feed to flow along the inner wall of the sphere formed by the lower and upper die punches, spreading evenly. After natural cooling to room temperature, a uniform spherical shell is formed, i.e., a porous hollow metal sphere green body. Finally, the porous hollow metal sphere green body undergoes high-temperature heat treatment to remove the binder. Simultaneously, this invention allows for the greening of porous hollow metal spheres, forming porous hollow metal spheres with certain strength and rigidity. The prepared porous hollow metal spheres have uniform pore size, smooth and even pore walls, and their pore structure can be precisely controlled as needed. They also possess characteristics such as low density, high specific strength, and high specific stiffness, which can meet the significant demand for porous hollow metal spheres and porous materials for energy absorption, sound insulation, and heat insulation in fields such as aviation, aerospace, transportation, machinery manufacturing, weaponry, and construction. Furthermore, the preparation process of this invention is relatively short, low-cost, and easy to mass-produce, making it suitable for preparing porous metal materials and components.

[0020] The above method is characterized in that the metal powder in step one is titanium alloy powder, aluminum alloy powder, copper alloy powder, stainless steel powder, nickel-based alloy powder, or high-entropy alloy powder; the volume content of the metal powder in the metal powder feed is 50% to 70%, and the binder is high-density polyethylene, polyoxymethylene, or paraffin wax. This invention prepares porous hollow metal spheres with different compositions by controlling the composition of the metal powder. These metal powders possess excellent comprehensive properties such as low density, high specific strength, high specific stiffness, excellent corrosion resistance, high temperature resistance, low temperature resistance, non-magnetic properties, and weldability, meeting the application needs of aviation, aerospace, nuclear industry, weaponry, marine, petroleum, and chemical industries. This invention ensures the fluidity of the heated metal powder feed by controlling the volume content of the metal powder in the metal powder feed, thereby ensuring the uniform structure of the prepared porous hollow metal spheres. This achieves simultaneous control of porosity during the preparation of porous hollow metal spheres, improving the molding effect.

[0021] The above method is characterized in that the mass M of the metal powder feed in step two satisfies: Where M is the mass of the metal powder feed, R is the outer radius of the porous hollow metal sphere, r is the inner radius of the porous hollow metal sphere, ρ1 and ρ2 are the densities of the metal powder and binder, respectively, and V1 and V2 are the volumes of the metal powder and binder, respectively. This invention, through a designed formula, adjusts the mass of the metal powder feed based on the radii of the upper and lower concave hemispheres in the mold (which are the outer radii of the porous hollow metal spheres), as well as the densities and volumes of the metal powder and binder. This controls the wall thickness of the porous hollow metal spheres and allows for the preparation of porous hollow metal spheres of different sizes by combining different radii of the upper and lower concave hemispheres.

[0022] The above method is characterized in that the heating process in step four is as follows: heating to 65℃~130℃ and then holding at that temperature for 3min~5min. This invention, by controlling the heating temperature and holding time, heats the metal powder feed to a semi-solid state, giving it a certain degree of fluidity. This ensures that the feed is evenly spread along the inner wall of the mold, preventing the metal powder feed from being too solid and unable to flow due to excessively low temperature, and also preventing the binder from melting into a liquid and separating from the metal powder due to excessively high temperature, thus failing to prepare uniform porous hollow metal spheres.

[0023] The method described above is characterized in that the rotational speed of the rotary table in step five is 400 rpm to 600 rpm. This invention ensures that the metal powder is evenly spread along the inner surface of the mold by controlling the rotational speed of the rotary table, preventing the problem of insufficient spreading of the powder on the inner surface of the mold due to excessively low speed, and avoiding the drawbacks of excessively high speed leading to increased energy consumption and higher manufacturing costs.

[0024] The above method is characterized in that the high-temperature heat treatment process in step seven is as follows: heating to 0.7T m ~0.9T m After heat preservation for 1 to 2 hours, the T m The melting point of the metal powder is [value missing]. This invention controls the heating temperature to remove the binder without damaging the overall structure of the porous hollow metal sphere green body, allowing the metal powder to form a metallurgical bond, resulting in porous hollow metal spheres with certain strength and rigidity.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] 1. This invention uses an upper die and a lower die with multiple concave hemispheres distributed on their surfaces to close the mold, thereby producing multiple porous hollow metal spheres in one operation. This results in high production efficiency and low production cost. By controlling the diameter of the multiple concave hemispheres on the lower die and making the diameters vary in a gradient, porous hollow metal spheres with different diameters can be produced in one operation, thus improving production efficiency.

[0027] 2. In this invention, metal powder is fed into the concave hemisphere of the lower die, and then the die is rotated at high speed, so that the feed is evenly spread along the inner wall of the concave hemisphere, while air is drawn in, and a porous hollow metal ball is spontaneously formed in situ. The production efficiency is high. By adjusting the diameter of the concave hemisphere of the die, the weight of the metal feed, and the rotation speed of the rotary table, porous hollow metal balls with uniform wall thickness, smooth surface, and controllable macroscopic dimensions can be obtained. They have characteristics such as low density, high specific strength, heat insulation, and sound insulation.

[0028] 3. The porous hollow metal spheres prepared by this invention are key raw materials for preparing lightweight, high-strength, and stable and reliable porous metal materials. High-performance porous metal materials that meet the urgent needs of the automotive, aerospace, steel metallurgy, nuclear industry and other fields can be obtained by optimizing the macroscopic characteristics, stacking method and preparation process of porous materials.

[0029] 4. The porous hollow metal spheres prepared by this invention can have their pore parameters adjusted according to the usage environment, which is beneficial to achieving synergistic control between the pore structure of porous metal materials and their service performance.

[0030] 5. The mold prepared by this invention can produce complete porous hollow metal spheres without diffusion welding, and has a low surface roughness, which meets the application requirements.

[0031] 6. The mold prepared by the present invention can produce porous hollow metal spheres with different macroscopic dimensions in the same batch, and the wall thickness of the spheres can be adjusted according to the performance of the application environment.

[0032] 7. The mold prepared by this invention can easily realize the stable batch production of porous hollow metal spheres, significantly reducing production costs.

[0033] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of the mold for preparing the porous hollow metal spheres of the present invention.

[0035] Figure 2 This is a schematic diagram of the upper die punch in the mold for preparing the porous hollow metal sphere of the present invention.

[0036] Figure 3 yes Figure 2 AA sectional view.

[0037] Figure 4 yes Figure 3 Enlarged view of point B.

[0038] Figure 5 This is a schematic diagram of the lower die punch in the mold for preparing the porous hollow metal sphere of the present invention.

[0039] Figure 6 yes Figure 5 CC section view.

[0040] Figure 7 yes Figure 6 Enlarged view of point D.

[0041] Figure 8 This is a schematic diagram of the structure of the porous hollow metal sphere green blank prepared in Embodiment 2 of the present invention.

[0042] Figure 9 This is a schematic diagram of the structure of the porous hollow metal sphere prepared in Embodiment 2 of the present invention.

[0043] Explanation of reference numerals in the attached figures:

[0044] 1—Upper die punch; 1-1—Upper concave hemisphere; 1-2—Upper screw;

[0045] 1-3—Circular concave platform; 2—Lower die punch; 2-1—Concave hemisphere;

[0046] 2-2—Lower half screw; 2-3—Annular boss; 3—Bolt hole;

[0047] 4—Fixing bolts. Detailed Implementation

[0048] The preparation mold for a porous hollow metal sphere of the present invention is described in detail through Example 1.

[0049] Example 1

[0050] like Figure 1 , Figure 2 , Figure 3 , Figure 5 and Figure 6 As shown in the figure, a mold for preparing a porous hollow metal ball according to this embodiment is characterized in that the mold includes an upper die punch 1 and a lower die punch 2. The lower surface of the upper die punch 1 is provided with a plurality of uniformly distributed upper concave hemispheres 1-1, and the upper surface of the lower die punch 2 is provided with a plurality of lower concave hemispheres 2-1 corresponding to the upper concave hemispheres 1-1. The sides of the upper die punch 1 and the lower die punch 2 are respectively provided with upper half screws 1-2 and lower half screws 2-2. Bolt holes 3 are opened on both the upper die punch 1 and the lower die punch 2.

[0051] It should be noted that by using an upper die punch 1 and a lower die punch 2 with multiple concave hemispheres 1-1 and 2-1 distributed on their surfaces to close the mold, the concave hemispheres 1-1 and 2-1 form a spherical space, which can produce multiple porous hollow metal spheres at once, resulting in high production efficiency and reduced manufacturing costs.

[0052] It should be noted that the upper screw 1-2 and the lower screw 2-2 are combined to form a single screw, which facilitates mounting with the rotary table.

[0053] It should be noted that bolt holes 3 are provided on both the upper die punch 1 and the lower die punch 2, and the mold is fixed by fixing bolts 4 when the mold is closed, so as to ensure the molding effect.

[0054] like Figure 4 and Figure 7 As shown, in this embodiment, the diameter of the concave hemisphere 2-1 is 0.5mm to 5.0mm, and an annular boss 2-3 is provided on the outer edge of the concave hemisphere 2-1. The height of the annular boss 2-3 is 1.0mm to 1.5mm, and the width is 1.5mm to 2.0mm. The outer edge of the upper concave hemisphere 1-1 is provided with an annular recess 1-3 corresponding to the annular boss 2-3. By controlling the diameter of the concave hemisphere 2-1, porous hollow metal spheres of different sizes can be prepared. Furthermore, by controlling the diameter of multiple concave hemispheres 2-1 on the lower die punch 2 and making the diameters change in a gradient, porous hollow metal spheres of different diameters can be produced in one operation, improving production efficiency. The annular boss 2-3 and the annular recess 1-3 ensure the accuracy of mold closing and improve the quality of the porous hollow metal spheres.

[0055] In this embodiment, the distance between adjacent concave hemispheres 1-1 on the upper die punch 1 is 3mm to 4mm. By controlling the distance between adjacent concave hemispheres 1-1, the adjacent concave hemispheres 1-1 do not affect each other.

[0056] In this embodiment, the surface roughness of the upper die punch 1 and the lower die punch 2 does not exceed 1.6 μm. This invention ensures the surface quality of the porous hollow metal sphere by controlling the surface roughness of the upper die punch 1 and the lower die punch 2.

[0057] The preparation method of a porous hollow metal sphere of the present invention is described in detail through Examples 2 to 8.

[0058] Example 2

[0059] This embodiment includes the following steps:

[0060] Step 1: Mix 50g of titanium alloy powder and 10g of high-density polyethylene to obtain metal powder feed;

[0061] Step 2: Place the metal powder obtained in Step 1 into the concave hemisphere 2-1 of the lower die punch 2 to obtain the loading lower die punch;

[0062] Step 3: Combine the lower die punch and upper die punch 1 obtained in Step 2 and fix them with bolts to obtain the loading mold;

[0063] Step 4: Heat the filling mold obtained in Step 3 to 70°C and hold it at that temperature for 4 minutes to obtain the heated filling mold;

[0064] Step 5: Fix the upper screw 1-2 and lower screw 2-2 of the heating and loading mold obtained in Step 4 to the rotary table. Then start the rotary table to make the heating and loading mold rotate at a speed of 500 rpm with the upper screw 1-2 and lower screw 2-2 as the axis. After rotating for 3 minutes, turn off the rotary table to obtain the rotating loading mold.

[0065] Step 6: After the rotating loading mold obtained in Step 5 has cooled naturally to room temperature, open it to obtain a porous hollow metal sphere green blank.

[0066] Step 7: Heat the porous hollow metal sphere green billet obtained in Step 6 to 0.85T. m After heat preservation for 2 hours, the T m The melting point of the metal powder is used to obtain porous hollow metal spheres.

[0067] Testing revealed that the porous hollow metal spheres prepared in this embodiment have a sphericity of 0.95 or higher, a wall thickness of 0.3 mm, and a density of 1.75 g / cm³. 3 .

[0068] Figure 8 This is a schematic diagram of the structure of the porous hollow metal sphere green blank prepared in this embodiment. Figure 9 This is a schematic diagram of the structure of the porous hollow metal sphere prepared in this embodiment. Figure 8 and Figure 9 As can be seen from the figure, the porous hollow metal sphere green blank prepared in this embodiment has a smooth surface and high sphericity. The porous hollow metal sphere obtained after high-temperature heat treatment still maintains a complete spherical structure.

[0069] Example 3

[0070] This embodiment includes the following steps:

[0071] Step 1: Mix metal powder and polyoxymethylene to obtain metal powder feed;

[0072] Step 2: Place the metal powder obtained in Step 1 into the concave hemisphere 2-1 of the lower die punch 2 to obtain the loading lower die punch;

[0073] Step 3: Combine the lower die punch and upper die punch 1 obtained in Step 2 and fix them with bolts to obtain the loading mold;

[0074] Step 4: Heat the loading mold obtained in Step 3 to 65℃~130℃ and keep it at that temperature for 3 minutes to obtain the heated loading mold;

[0075] Step 5: Fix the upper screw 1-2 and lower screw 2-2 of the heating and loading mold obtained in Step 4 to the rotary table. Then start the rotary table to make the heating and loading mold rotate at a speed of 600 rpm with the upper screw 1-2 and lower screw 2-2 as the axis. After rotating for 3 minutes, turn off the rotary table to obtain the rotated loading mold.

[0076] Step 6: After the rotating loading mold obtained in Step 5 has cooled naturally to room temperature, open it to obtain a porous hollow metal sphere green blank.

[0077] Step 7: Heat the porous hollow metal sphere green billet obtained in Step 6 to 0.85T. m After heat preservation for 2 hours, the T m The melting point of the metal powder is used to obtain porous hollow metal spheres.

[0078] Testing revealed that the porous hollow metal spheres prepared in this embodiment have a sphericity of 0.95 or higher, a wall thickness of 0.15 mm, and a density of 0.94 g / cm³. 3 .

[0079] Example 4

[0080] This embodiment includes the following steps:

[0081] Step 1: Mix the metal powder and paraffin wax to obtain the metal powder feed;

[0082] Step 2: Place the metal powder obtained in Step 1 into the concave hemisphere 2-1 of the lower die punch 2 to obtain the loading lower die punch;

[0083] Step 3: Combine the lower die punch and upper die punch 1 obtained in Step 2 and fix them with bolts to obtain the loading mold;

[0084] Step 4: Heat the loading mold obtained in Step 3 to 65℃~130℃ and keep it at that temperature for 5 minutes to obtain the heated loading mold;

[0085] Step 5: Fix the upper screw 1-2 and lower screw 2-2 of the heating and loading mold obtained in Step 4 to the rotary table. Then start the rotary table to make the heating and loading mold rotate at a speed of 450 rpm with the upper screw 1-2 and lower screw 2-2 as the axis. After rotating for 2.5 minutes, turn off the rotary table to obtain the rotated loading mold.

[0086] Step 6: After the rotating loading mold obtained in Step 5 has cooled naturally to room temperature, open it to obtain a porous hollow metal sphere green blank.

[0087] Step 7: Heat the porous hollow metal sphere green billet obtained in Step 6 to 0.85T. m After heat preservation for 2 hours, the Tm The melting point of the metal powder is used to obtain porous hollow metal spheres.

[0088] Testing revealed that the porous hollow metal spheres prepared in this embodiment have a sphericity of 0.95 or higher, a wall thickness of 0.2 mm, and a density of 1.22 g / cm³. 3 .

[0089] Example 5

[0090] This embodiment includes the following steps:

[0091] Step 1: Mix metal powder and high-density polyethylene to obtain metal powder feed;

[0092] Step 2: Place the metal powder obtained in Step 1 into the concave hemisphere 2-1 of the lower die punch 2 to obtain the loading lower die punch;

[0093] Step 3: Combine the lower die punch and upper die punch 1 obtained in Step 2 and fix them with bolts to obtain the loading mold;

[0094] Step 4: Heat the loading mold obtained in Step 3 to 65℃~130℃ and keep it at that temperature for 3 minutes to obtain the heated loading mold;

[0095] Step 5: Fix the upper screw 1-2 and lower screw 2-2 of the heating and loading mold obtained in Step 4 to the rotary table. Then start the rotary table to make the heating and loading mold rotate at a speed of 500 rpm with the upper screw 1-2 and lower screw 2-2 as the axis. After rotating for 2 minutes, turn off the rotary table to obtain the rotating loading mold.

[0096] Step 6: After the rotating loading mold obtained in Step 5 has cooled naturally to room temperature, open it to obtain a porous hollow metal sphere green blank.

[0097] Step 7: Heat the porous hollow metal sphere green billet obtained in Step 6 to 0.7T. m After heat preservation for 1.5 hours, the T m The melting point of the metal powder is used to obtain porous hollow metal spheres.

[0098] Testing revealed that the porous hollow metal spheres prepared in this embodiment have a sphericity of 0.95 or higher, a wall thickness of 0.2 mm, and a density of 0.73 g / cm³. 3 .

[0099] Example 6

[0100] This embodiment includes the following steps:

[0101] Step 1: Mix metal powder and polyoxymethylene to obtain metal powder feed;

[0102] Step 2: Place the metal powder obtained in Step 1 into the concave hemisphere 2-1 of the lower die punch 2 to obtain the loading lower die punch;

[0103] Step 3: Combine the lower die punch and upper die punch 1 obtained in Step 2 and fix them with bolts to obtain the loading mold;

[0104] Step 4: Heat the loading mold obtained in Step 3 to 65℃~130℃ and hold for 4 minutes to obtain the heated loading mold;

[0105] Step 5: Fix the upper screw 1-2 and lower screw 2-2 of the heating and loading mold obtained in Step 4 to the rotary table. Then start the rotary table to make the heating and loading mold rotate at a speed of 500 rpm with the upper screw 1-2 and lower screw 2-2 as the axis. After rotating for 3 minutes, turn off the rotary table to obtain the rotating loading mold.

[0106] Step 6: After the rotating loading mold obtained in Step 5 has cooled naturally to room temperature, open it to obtain a porous hollow metal sphere green blank.

[0107] Step 7: Heat the porous hollow metal sphere green blank obtained in Step 6 to 0.9T. m After heat preservation for 1 hour, the T m The melting point of the metal powder is used to obtain porous hollow metal spheres.

[0108] Testing revealed that the porous hollow metal spheres prepared in this embodiment have a sphericity of 0.95 or higher, a wall thickness of 0.2 mm, and a density of 2.43 g / cm³. 3 .

[0109] Example 7

[0110] This embodiment includes the following steps:

[0111] Step 1: Mix the metal powder and paraffin wax to obtain the metal powder feed;

[0112] Step 2: Place the metal powder obtained in Step 1 into the concave hemisphere 2-1 of the lower die punch 2 to obtain the loading lower die punch;

[0113] Step 3: Combine the lower die punch and upper die punch 1 obtained in Step 2 and fix them with bolts to obtain the loading mold;

[0114] Step 4: Heat the loading mold obtained in Step 3 to 65℃~130℃ and keep it at that temperature for 5 minutes to obtain the heated loading mold;

[0115] Step 5: Fix the upper screw 1-2 and lower screw 2-2 of the heating and loading mold obtained in Step 4 to the rotary table. Then start the rotary table to make the heating and loading mold rotate at a speed of 500 rpm with the upper screw 1-2 and lower screw 2-2 as the axis. After rotating for 2.5 minutes, turn off the rotary table to obtain the rotated loading mold.

[0116] Step 6: After the rotating loading mold obtained in Step 5 has cooled naturally to room temperature, open it to obtain a porous hollow metal sphere green blank.

[0117] Step 7: Heat the porous hollow metal sphere green billet obtained in Step 6 to 0.75T. m After heat preservation for 2 hours, the T m The melting point of the metal powder is used to obtain porous hollow metal spheres.

[0118] Testing revealed that the porous hollow metal spheres prepared in this embodiment have a sphericity of 0.95 or higher, a wall thickness of 0.2 mm, and a density of 2.14 g / cm³. 3 .

[0119] Example 8

[0120] This embodiment includes the following steps:

[0121] Step 1: Mix metal powder and high-density polyethylene to obtain metal powder feed;

[0122] Step 2: Place the metal powder obtained in Step 1 into the concave hemisphere 2-1 of the lower die punch 2 to obtain the loading lower die punch;

[0123] Step 3: Combine the lower die punch and upper die punch 1 obtained in Step 2 and fix them with bolts to obtain the loading mold;

[0124] Step 4: Heat the loading mold obtained in Step 3 to 65℃~130℃ and hold for 4 minutes to obtain the heated loading mold;

[0125] Step 5: Fix the upper screw 1-2 and lower screw 2-2 of the heating and loading mold obtained in Step 4 to the rotary table. Then start the rotary table to make the heating and loading mold rotate at a speed of 600 rpm with the upper screw 1-2 and lower screw 2-2 as the axis. After rotating for 2 minutes, turn off the rotary table to obtain the rotating loading mold.

[0126] Step 6: After the rotating loading mold obtained in Step 5 has cooled naturally to room temperature, open it to obtain a porous hollow metal sphere green blank.

[0127] Step 7: Heat the porous hollow metal sphere green blank obtained in Step 6 to 0.9T. m After heat preservation for 2 hours, the Tm The melting point of the metal powder is used to obtain porous hollow metal spheres.

[0128] Testing revealed that the porous hollow metal spheres prepared in this embodiment have a sphericity of 0.95 or higher, a wall thickness of 0.2 mm, and a density of 2.41 g / cm³. 3 .

[0129] Example 9

[0130] This embodiment includes the following steps:

[0131] Step 1: Mix metal powder and polyoxymethylene to obtain metal powder feed;

[0132] Step 2: Place the metal powder obtained in Step 1 into the concave hemisphere 2-1 of the lower die punch 2 to obtain the loading lower die punch;

[0133] Step 3: Combine the lower die punch and upper die punch 1 obtained in Step 2 and fix them with bolts to obtain the loading mold;

[0134] Step 4: Heat the loading mold obtained in Step 3 to 65℃~130℃ and keep it at that temperature for 5 minutes to obtain the heated loading mold;

[0135] Step 5: Fix the upper screw 1-2 and lower screw 2-2 of the heating and loading mold obtained in Step 4 to the rotary table. Then start the rotary table to make the heating and loading mold rotate at a speed of 400 rpm with the upper screw 1-2 and lower screw 2-2 as the axis. After rotating for 3 minutes, turn off the rotary table to obtain the rotated loading mold.

[0136] Step 6: After the rotating loading mold obtained in Step 5 has cooled naturally to room temperature, open it to obtain a porous hollow metal sphere green blank.

[0137] Step 7: Heat the porous hollow metal sphere green billet obtained in Step 6 to 0.85T. m After heat preservation for 2 hours, the T m The melting point of the metal powder is used to obtain porous hollow metal spheres.

[0138] Testing revealed that the porous hollow metal spheres prepared in this embodiment have a sphericity of 0.95 or higher, a wall thickness of 0.2 mm, and a density of 1.77 g / cm³. 3 .

[0139] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing a porous hollow metal sphere, characterized in that, The mold used in this method includes an upper die punch (1) and a lower die punch (2). The lower surface of the upper die punch (1) is provided with a plurality of evenly distributed upper concave hemispheres (1-1). The upper surface of the lower die punch (2) is provided with a plurality of lower concave hemispheres (2-1) corresponding to the upper concave hemispheres (1-1). The sides of the upper die punch (1) and the lower die punch (2) are respectively provided with upper half screws (1-2) and lower half screws (2-2). Bolt holes (3) are provided on both the upper die punch (1) and the lower die punch (2). The diameter of the lower concave hemispheres (2-1) is 0. The concave hemisphere (2-1) has a circular annular boss (2-3) on its outer edge, with a height of 1.0mm to 1.5mm and a width of 1.5mm to 2.0mm. The upper concave hemisphere (1-1) has a circular annular recess (1-3) on its outer edge corresponding to the circular annular boss (2-3). The distance between adjacent upper concave hemispheres (1-1) on the upper die punch (1) is 3mm to 4mm. The surface roughness of the upper die punch (1) and the lower die punch (2) does not exceed 1.6μm. The method includes the following steps: Step 1: Mix the metal powder and binder to obtain the metal powder feed; Step 2: Place the metal powder obtained in Step 1 into the concave hemisphere (2-1) of the lower die punch (2) to obtain the loading lower die punch; Step 3: Combine the lower and upper punches (1) obtained in Step 2 and fix them with bolts to obtain the loading mold; Step 4: Heat the loading mold obtained in Step 3 to obtain a heated loading mold; Step 5: Fix the upper screw (1-2) and lower screw (2-2) of the heating and loading mold obtained in Step 4 to the rotary table. Then start the rotary table to make the heating and loading mold rotate with the upper screw (1-2) and lower screw (2-2) as the axis. After rotating for 2 to 3 minutes, turn off the rotary table to obtain the rotating loading mold. Step 6: After the rotating loading mold obtained in Step 5 has cooled naturally to room temperature, open it to obtain a porous hollow metal sphere green blank. Step 7: Perform high-temperature heat treatment on the porous hollow metal sphere green blank obtained in Step 6 to obtain porous hollow metal spheres.

2. The method for preparing a porous hollow metal sphere according to claim 1, characterized in that, The metal powder mentioned in step one is titanium alloy powder, aluminum alloy powder, copper alloy powder, stainless steel powder, nickel-based alloy powder, or high-entropy alloy powder; the volume content of the metal powder in the metal powder feed is 50%~70%, and the binder is high-density polyethylene, polyoxymethylene, or paraffin wax.

3. The method for preparing a porous hollow metal sphere according to claim 1, characterized in that, The mass of the metal powder feed in step two M satisfy: ,in, M The quality of the metal powder feed. R The outer radius of the porous hollow metal sphere r Let be the inner radius of the porous hollow metal sphere. ρ 1 and ρ 2 represents the density of the metal powder and the binder, respectively. V 1 and V 2 represents the volume content of the metal powder and the binder, respectively.

4. The method for preparing a porous hollow metal sphere according to claim 1, characterized in that, The heating process described in step four is as follows: heat to 65℃~130℃ and then keep warm for 3min~5min.

5. The method for preparing a porous hollow metal sphere according to claim 1, characterized in that, The rotational speed of the rotary table in step five is 400 rpm to 600 rpm.

6. The method for preparing a porous hollow metal sphere according to claim 1, characterized in that, The high-temperature heat treatment process described in step seven is as follows: heating to 0.7T m ~0.9T m After heat preservation for 1-2 hours, the T m This is the melting point of the metal powder.

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