A vacuum electrode induction melting double-flow gas atomization metal powder device

Abstract

The invention discloses a vacuum electrode induction melting double-flow gas atomization metal powder device, the technical solution of which includes a melting chamber and an atomization chamber, the melting chamber is located above the atomization chamber, and the melting chamber is connected to the atomization chamber, the melting chamber includes an induction coil, an atomization nozzle and a vertically arranged metal rod, the atomization chamber includes a shell, the shell top wall is arranged as a double-layer cavity structure, the upper end of the shell top wall is provided with a high-pressure air inlet, the lower surface of the top wall is provided with a plurality of air outlets, the air outlets are extended from the center of the top wall to the edge so as to be arranged in a long strip shape, and the plurality of air outlets are evenly distributed in an annular shape along the central axis of the shell; the lower end of the atomization chamber is provided with a collection tank and a gas recovery device, and the collection tank and the gas recovery device are both connected to the shell. The device can be used to prepare fine spherical metal powders, and can reduce the "satellite powder" phenomenon, which is conducive to improving the fluidity of metal powders.

Description

Technical Field

[0001] The invention relates to the field of preparation of spherical metal powder materials, and more particularly to a vacuum electrode induction melting double-flow gas atomization metal powder device. Background Art

[0002] Fine spherical metal powder is an important raw material for additive manufacturing (3D printing), metal injection molding, hot isostatic pressing and coating technologies. Gas atomization is one of the main methods for preparing fine spherical metal powder. Its principle is to break the molten metal into tiny droplets through the impact of high-speed gas (atomizing medium). The droplets are spheroidized due to surface tension during their flight in the atomization chamber and quickly condensed into spherical or nearly spherical metal powder particles of different particle sizes, which are finally collected in the powder tank by the grading system.

[0003] However, the metal powder currently prepared by aerosolization has the phenomenon of "satellite powder" where small particles adhere to large particles, reducing the fluidity and bulk density of the powder. Too much satellite powder will reduce the process performance of the powder and the final product quality. For example, in 3D printing, powder with poor fluidity is more likely to link up, causing "bridging", or powder blockage in the printing equipment, affecting the uniform distribution of the powder layer.

[0004] In contrast, fine spherical metal powders with better fluidity are more in line with practical needs. High-fluidity powders usually have a higher bulk density and can be more easily spread into a uniform powder layer. For example, they can be more easily applied to technologies such as additive manufacturing and coating. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a vacuum electrode induction melting double-flow gas atomization metal powder device, which can be used to prepare fine spherical metal powder and can reduce the "satellite powder" phenomenon, which is beneficial to improving the fluidity of the metal powder.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a vacuum electrode induction melting double-flow gas atomization metal powder device, comprising a melting chamber and an atomization chamber, wherein the melting chamber is located above the atomization chamber, and the melting chamber and the atomization chamber are connected at the connection, wherein the melting chamber comprises an induction coil, an atomization nozzle and a vertically arranged metal rod, wherein the induction coil is arranged at the middle and lower end of the metal rod and is used to heat the metal rod, wherein the atomization nozzle is arranged at the connection between the lower end of the melting chamber and the atomization chamber, wherein the atomization nozzle is externally connected to a first high-pressure gas supply device, and wherein the atomization nozzle is used to spray the metal liquid dripping after the metal rod is melted into the atomization chamber;

[0007] The atomization chamber includes a shell, the top wall of the shell is set as a double-layer cavity structure, the upper end of the top wall of the shell is provided with a high-pressure air inlet, one end of the high-pressure air inlet is externally connected to a second high-pressure gas supply device, and the other end is connected to the cavity in the top wall, and a plurality of air outlets are provided on the lower surface of the top wall, the air outlets are connected to the cavity in the top wall, and the air outlets extend from the center of the top wall to the edge so as to be arranged in a long strip shape, and the plurality of air outlets are evenly distributed in a ring shape along the central axis of the shell;

[0008] A collecting tank and a gas recovery device are provided at the lower end of the atomization chamber. Both the collecting tank and the gas recovery device are connected to the shell. The collecting tank is used to collect the prepared metal powder, and the gas recovery device is used to recover the gas sprayed from the atomization nozzle and the gas outlet.

[0009] As a further improvement of the present invention, a lower partition is arranged in the atomization chamber, the lower partition is connected to the inner wall of the shell, a plurality of exhaust ports for metal powder to pass through are arranged on the lower partition, the exhaust ports and the air outlets are arranged one above the other, a suction ball is arranged in the shell, the suction ball is located below the lower partition, the suction ball is hollow, a plurality of suction holes are arranged on the side wall of the suction ball, the gas recovery device is a device for providing negative pressure, and the negative pressure end of the gas recovery device is connected to the interior of the suction ball through a pipe.

[0010] By adopting the above technical scheme, the gas recovery device sucks air into the atomizing chamber through the suction ball, and due to the setting of the lower partition and the exhaust port, the high-pressure gas ejected from the upper outlet can directly pass through the exhaust port through the lower partition and be drawn out of the atomizing chamber through the suction ball after flowing downward. When the sheath gas flow flows from the upper part to the lower partition, under the action of the downward spray force of the gas outlet and the downward suction force of the exhaust port, the sheath gas flow is kept in a state of vertical downward flow, and the suction force of the exhaust port can strengthen the downward flow of the sheath gas flow. Compared with no partition, after the sheath gas flow flows to the lower part, due to the blocking effect of the lower end of the shell, the sheath gas flow will be chaotic, resulting in the sheath gas flow losing its effect near the lower end of the shell. Therefore, the technical scheme can still guide and limit the metal powder being formed near the partition, and can strengthen this effect, thereby further reducing the "satellite powder" phenomenon, which is conducive to improving the fluidity of the metal powder. The setting of the suction ball makes the suction force of each exhaust port more uniform.

[0011] As a further improvement of the present invention, the outer side wall of the suction ball is coated with a filter screen, and the filter screen is used to prevent metal powder from entering the suction ball.

[0012] By adopting the above technical solution, it is prevented that the metal powder enters the suction ball through the suction hole and is sucked away.

[0013] As a further improvement of the present invention, a plurality of recessed portions and raised portions are provided on the upper surface of the lower partition, the recessed portions and raised portions have a smooth transition and are evenly distributed in a ring shape along the central axis of the lower partition, and each of the recessed portions is provided with the exhaust port.

[0014] By adopting the above technical solution, the metal powder can more easily pass through the exhaust port under the guidance of the transition surface between the recessed portion and the raised portion, thereby entering the collection tank below.

[0015] As a further improvement of the present invention, the upper surface of the lower partition plate is upwardly protruded opposite to the metal rod to form a guide cone, and the lower end of the guide cone extends outwardly to each of the recessed portions.

[0016] By adopting the above technical solution, the metal powder in the middle of the partition is the largest, and the guide cone guides the metal powder falling in the middle of the partition, so that the metal powder in the middle of the partition will not accumulate, and the metal powder can enter each exhaust port under the guidance of the guide cone, and then enter the collection tank below through the exhaust port.

[0017] As a further improvement of the present invention, a cooling channel is provided between the inner and outer walls of the shell, the cooling channel is provided with an outlet and an inlet, the outlet is located above the inlet, a cooling medium flows in the cooling channel, and the outlet is externally connected to a cooling medium supply device.

[0018] By adopting the above technical solution, the shell is cooled to avoid overheating of the shell, and the temperature of the atomization chamber can be reduced to accelerate the condensation of metal droplets.

[0019] As a further improvement of the present invention, the gases sprayed out from the atomizing nozzle and the gas outlet are both inert gases.

[0020] By adopting the above technical solution, the inert gas is stable and will not react with the high-temperature metal droplets, so the purity of the obtained metal powder can be maintained.

[0021] As a further improvement of the present invention, the gas sprayed from the atomizing nozzle is heated gas, and the gas temperature is 100°C-300°C.

[0022] By adopting the above technical solution, the kinetic energy of the gas at this temperature is high, which is beneficial to increasing the kinetic energy of the metal droplets.

[0023] As a further improvement of the present invention, the output end of the gas recovery device is connected to the input end of the first high-pressure gas supply device or the second high-pressure gas supply device.

[0024] By adopting the above technical solution, the gas can be recovered and recycled, which is helpful to reduce costs.

[0025] As a further improvement of the present invention, a plurality of high-pressure air inlets are provided, and the plurality of high-pressure air inlets are evenly distributed in a ring shape along the central axis of the top wall of the shell.

[0026] By adopting the above technical solution, the air pressure at each location of the cavity in the top wall is made closer, and the intensity of the sheath airflow ejected from each air outlet is made closer, which is more beneficial to reducing the "satellite powder" phenomenon.

[0027] Beneficial effects of the present invention: the induction coil heats the metal rod, so that the metal rod melts to form metal liquid and is impacted by the gas sprayed from the atomizing nozzle, the metal liquid breaks into tiny droplets, and after the droplets enter the atomizing chamber, they condense into metal powder particles and fall into the collection tank, so the device can be used to prepare fine spherical metal powder. In the atomizing chamber, high-pressure gas flows out from the long strip-shaped gas outlet, and forms a sheath gas flow flowing from top to bottom in the atomizing chamber. After the droplets enter the atomizing chamber, under the action of the sheath gas flow, the collision and adhesion between the droplets are reduced, thereby reducing the "satellite powder" phenomenon, which is beneficial to improving the fluidity of the metal powder. Each gas outlet extends from the center of the top wall to the edge and is arranged in a long strip shape. The shape and position of the gas outlet increase the distribution range of the sheath gas flow and the stability of the continuous spraying of the sheath gas flow, thereby improving the guiding and limiting effect of the sheath gas flow on the metal powder and reducing the "satellite powder" phenomenon. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic diagram of the three-dimensional structure of Example 1;

[0029] Figure 2 It is a schematic diagram of the three-dimensional structure of the connection between the melting chamber and the atomizing chamber;

[0030] Figure 3 is a cross-sectional view of Example 1;

[0031] Figure 4 is a schematic diagram of the three-dimensional structure of Example 2;

[0032] Figure 5 is a cross-sectional view of Example 2;

[0033] Figure 6 for Figure 5 The enlarged view of point A in the middle;

[0034] Figure 7 It is a schematic diagram of the three-dimensional structure of the lower partition and the suction ball.

[0035] Figure numerals: 1. melting chamber; 11. induction coil; 12. atomizing nozzle; 13. metal rod; 2. atomizing chamber; 21. shell; 22. high-pressure air inlet; 23. air outlet; 24. cooling channel; 3. collecting tank; 4. gas recovery device; 5. lower partition; 51. exhaust port; 52. recessed portion; 53. raised portion; 54. guide cone; 6. suction ball; 61. suction hole; 62. filter. DETAILED DESCRIPTION

[0036] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. The same parts are represented by the same reference numerals. It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to directions in the accompanying drawings, and the words "bottom surface" and "top surface", "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0037] Embodiment 1:

[0038] Reference Figure 1 , Figure 2 , Figure 3 As shown, a vacuum electrode induction melting double-flow gas atomization metal powder device of this embodiment includes a melting chamber 1 and an atomization chamber 2. The melting chamber 1 is located above the atomization chamber 2, and the melting chamber 1 and the atomization chamber 2 are connected. The melting chamber 1 includes an induction coil 11, an atomization nozzle 12 and a vertically arranged metal rod 13. The induction coil 11 is arranged at the lower end of the metal rod 13 and is used to heat the metal rod 13. The metal rod 13 is cylindrical, and a rotating mechanism can be set to drive the metal rod 13 to rotate around the central axis, so that the metal rod 13 is heated more evenly. The atomization nozzle 12 is arranged at the connection between the lower end of the melting chamber 1 and the atomization chamber 2. The atomization nozzle 12 is externally connected to a first high-pressure gas supply device. The atomization nozzle 12 is used to spray the metal liquid dripping after the metal rod 13 is melted into the atomization chamber 2. The gas sprayed by the atomization nozzle 12 is a heated inert gas, and the temperature of the inert gas is 100℃-300℃. The first high-pressure gas supply device is a device capable of increasing high-pressure gas, such as an air pump.

[0039] Reference Figure 2 , Figure 3As shown, the atomizing chamber 2 includes a housing 21, the top wall of the housing 21 is arranged as a double-layer cavity structure, and a high-pressure air inlet 22 is arranged at the upper end of the top wall of the housing 21, and a plurality of high-pressure air inlets 22 are arranged, and the plurality of high-pressure air inlets 22 are evenly distributed in a ring shape along the central axis of the top wall of the housing 21. One end of the high-pressure air inlet 22 is externally connected to a second high-pressure gas supply device, and the other end is connected to the cavity in the top wall. The second high-pressure gas supply device is a device capable of increasing high-pressure gas, such as an air pump. And the first high-pressure gas supply device and the second high-pressure gas supply device can be the same device. A plurality of air outlets 23 are arranged on the lower surface of the top wall, and the air outlets 23 are connected to the cavity in the top wall. The air outlets 23 extend from the center of the top wall to the edge so as to be arranged in a long strip shape, and the plurality of air outlets 23 are evenly distributed in a ring shape along the central axis of the housing 21. The gas ejected from the air outlet 23 is an inert gas.

[0040] Reference Figure 1 , Figure 3 As shown, a collection tank 3 and a gas recovery device 4 are provided at the lower end of the atomizing chamber 2, and both the collection tank 3 and the gas recovery device 4 are connected to the shell 21. The collection tank 3 is used to collect the prepared metal powder, and the gas recovery device 4 is used to recover the gas sprayed from the atomizing nozzle 12 and the gas outlet 23. The output end of the gas recovery device 4 is connected to the input end of the first high-pressure gas supply device or the second high-pressure gas supply device. The lower end of the shell 21 is in an inverted cone shape, and the tank body is located in the middle of the lower end of the shell 21, so that the metal powder enters the tank body under the guidance of the cone surface.

[0041] Reference Figure 3 As shown, a cooling channel 24 is provided between the inner and outer walls of the shell 21. The cooling channel 24 is provided with an outlet and an inlet. The outlet is located above the inlet. A cooling medium flows in the cooling channel 24. The cooling medium can be a gas or liquid that can absorb heat. The outlet is externally connected to a cooling medium supply device, which can be an air pump or a liquid pump.

[0042] In this embodiment, the metal rod 13 is a Ti6Al4V titanium alloy rod with a diameter of 50 mm, and the gas sprayed by the atomizing nozzle 12 is argon. When the size of the gas outlet 23 is set to 10 mm in width, 1200 mm in length, the number is set to 36, the argon pressure is 4 MPa, and the background sheath gas flow rate is 1200 Nm3 / h, the average particle size of the obtained Ti6Al4V titanium alloy powder is 58 μm, and the Hall flow rate of the 15-45 μm particle size powder measured according to the ASTMB213 standard is 29 s / 50 g, the stacking angle is 21.5°, and the sphericity is 0.926.

[0043] When the size of the gas outlet 23 is set to 15 mm in width, 1800 mm in length, the number is set to 36, the argon pressure is 4 MPa, and the background sheath gas flow rate is 800 Nm3 / h, the average particle size of the obtained Ti6Al4V titanium alloy powder is 58 μm. According to the ASTM B213 standard, the Hall flow rate of the powder with a particle size of 15-45 μm is 33 s / 50 g, the stacking angle is 26.9°, and the sphericity is 0.923.

[0044] Working principle:

[0045] The rotating cylindrical metal rod 13 is heated and melted by the induction coil 11, and the molten metal liquid flows continuously into the atomizing chamber 2 from the tip of the rod, and is impacted and broken by the supersonic inert gas ejected by the atomizing nozzle 12 in the atomizing zone, forming countless tiny droplets. In this process, the top wall cavity of the atomizing chamber 2 is continuously injected with high-pressure inert gas, which flows out from the long strip gas outlet 23 arranged in an annular shape and uniformly spaced, forming a sheath gas flow flowing from top to bottom in the atomizing chamber 2. Under the action of the sheath gas flow, the mutual collision and adhesion between the atomized droplets are reduced, thereby reducing the formation of satellite powder. After the atomized droplets are cooled in the atomizing chamber 2, they enter the collecting tank 3.

[0046] Embodiment 2:

[0047] Reference Figure 4 , Figure 5 , Figure 6 , Figure 7 As shown, the difference between this embodiment and embodiment 1 is that: a lower partition 5 is provided in the atomizing chamber 2, the lower partition 5 is connected to the inner wall of the shell 21, a plurality of exhaust ports 51 for metal powder to pass through are provided on the lower partition 5, the exhaust ports 51 are arranged one above the other and opposite to the gas outlet 23, a suction ball 6 is provided in the shell 21, the suction ball 6 is located below the lower partition 5, the suction ball 6 is hollow, a plurality of suction holes 61 are provided on the side wall of the suction ball 6, and a filter screen 62 is coated on the outer wall of the suction ball 6, and the filter screen 62 is used to prevent metal powder from entering the suction ball 6. The gas recovery device 4 is a device for providing negative pressure, and the negative pressure end of the gas recovery device 4 is connected to the inside of the suction ball 6 through a pipeline.

[0048] Reference Figure 5 , Figure 7 As shown, the upper surface of the lower partition 5 is provided with a plurality of recessed portions 52 and raised portions 53, which are smoothly transitioned and evenly spaced in a ring shape along the central axis of the lower partition 5, and each recessed portion 52 is provided with an exhaust port 51. The upper surface of the lower partition 5 is upwardly convexed opposite to the metal rod 13 to form a guide cone 54, and the lower end of the guide cone 54 extends outward to each recessed portion 52.

[0049] The above are only preferred embodiments of the present invention. The protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A vacuum electrode induction melting double-flow gas atomization metal powder device, comprising a melting chamber (1) and an atomization chamber (2), characterized in that: The melting chamber (1) is located above the atomizing chamber (2), and the melting chamber (1) and the atomizing chamber (2) are connected at a connection point. The melting chamber (1) includes an induction coil (11), an atomizing nozzle (12), and a vertically arranged metal rod (13). The induction coil (11) is arranged at the lower end of the metal rod (13) and is used to heat the metal rod (13). The atomizing nozzle (12) is arranged at a connection point between the lower end of the melting chamber (1) and the atomizing chamber (2). The atomizing nozzle (12) is externally connected to a first high-pressure gas supply device. The atomizing nozzle (12) is used to spray the metal liquid dripping after the metal rod (13) is melted into the atomizing chamber (2); The atomization chamber (2) comprises a shell (21), the top wall of the shell (21) is arranged as a double-layer cavity structure, the upper end of the top wall of the shell (21) is arranged with a high-pressure air inlet (22), one end of the high-pressure air inlet (22) is externally connected to a second high-pressure gas supply device, and the other end is communicated with the cavity in the top wall, a plurality of air outlets (23) are arranged on the lower surface of the top wall, the air outlets (23) are communicated with the cavity in the top wall, the air outlets (23) are all extended from the center of the top wall to the edge, and are arranged in a long strip shape, and the plurality of air outlets (23) are evenly distributed in a ring shape along the central axis of the shell (21); A collecting tank (3) and a gas recovery device (4) are provided at the lower end of the atomizing chamber (2); the collecting tank (3) and the gas recovery device (4) are both connected to the housing (21); the collecting tank (3) is used to collect the produced metal powder, and the gas recovery device (4) is used to recover the gas sprayed from the atomizing nozzle (12) and the gas outlet (23); A lower partition (5) is arranged in the atomizing chamber (2), the lower partition (5) is connected to the inner wall of the shell (21), a plurality of exhaust ports (51) for metal powder to pass through are arranged on the lower partition (5), the exhaust ports (51) and the gas outlet (23) are arranged one above the other, a suction ball (6) is arranged in the shell (21), the suction ball (6) is located below the lower partition (5), the suction ball (6) is hollow, and a plurality of suction holes (61) are arranged on the side wall of the suction ball (6), the gas recovery device (4) is a device for providing negative pressure, and the negative pressure end of the gas recovery device (4) is connected to the inside of the suction ball (6) through a pipeline; The outer wall of the suction ball (6) is coated with a filter screen (62), and the filter screen (62) is used to prevent metal powder from entering the suction ball (6); The upper surface of the lower baffle (5) is provided with a plurality of recessed portions (52) and raised portions (53), the recessed portions (52) and raised portions (53) are smoothly transitioned and are evenly spaced and distributed in a ring shape along the central axis of the lower baffle (5), and each recessed portion (52) is provided with the exhaust port (51); The upper surface of the lower partition (5) is convex upwardly facing the metal rod (13) to form a guide cone (54), and the lower end of the guide cone (54) extends outwardly to each of the recessed portions (52).

2. The vacuum electrode induction melting dual-flow gas atomization metal powder device according to claim 1, characterized in that: A cooling channel (24) is provided between the inner and outer walls of the shell (21), the cooling channel (24) is provided with an outlet and an inlet, the outlet is located above the inlet, a cooling medium flows in the cooling channel (24), and the outlet is externally connected to a cooling medium supply device.

3. The vacuum electrode induction melting dual-flow gas atomization metal powder device according to claim 1, characterized in that: The gases sprayed from the atomizing nozzle (12) and the gas outlet (23) are both inert gases.

4. The vacuum electrode induction melting dual-flow gas atomization metal powder device according to claim 3, characterized in that: The gas sprayed from the atomizing nozzle (12) is heated gas, and the gas temperature is 100°C-300°C.

5. The vacuum electrode induction melting dual-flow gas atomization metal powder device according to claim 3, characterized in that: The output end of the gas recovery device (4) is connected to the input end of the first high-pressure gas supply device or the second high-pressure gas supply device.

6. The vacuum electrode induction melting dual-flow gas atomization metal powder device according to claim 1, characterized in that: A plurality of high-pressure air inlets (22) are provided, and the plurality of high-pressure air inlets (22) are evenly distributed in a ring shape along the central axis of the top wall of the shell (21).

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