High-energy high-speed plasma atomization multi-wire processing method

Abstract

The invention discloses a high-energy high-speed plasma atomization multi-wire processing method which comprises the following steps: S1, synchronously conveying three or more groups of low-melting-point alloy wires at the same speed through a feeding mechanism, so that a plurality of groups of wires are intersected at the same intersection point; s2, an outlet of a single plasma torch is positioned above the wire intersection, ignition ports of the plasma torches and the wire intersection are overlapped in the vertical direction, the plasma torches are started, and molten metal columns are formed through smelting; s3, enabling the metal liquid column to freely fall to an inclined plate integrated ultrasonic rotating disc under the metal liquid column; s4, primary vacuum breaking is conducted when the metal liquid column is away from the rotating disc by a set distance, then the rotating disc is started to rotate at a high speed, an ultrasonic vibrator at the bottom of the rotating disc is started, secondary breaking is conducted through high-speed centrifugal force after the metal liquid column makes contact with the rotating disc, and meanwhile refining is completed under the ultrasonic vibration effect; plasma atomization of low-melting-point metal is achieved, the high quality of powder is guaranteed, meanwhile, the production efficiency is improved, and the production cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal powder preparation, and particularly relates to a high-energy high-speed plasma atomization multi-wire processing method. BACKGROUND

[0002] The plasma atomization technology has been widely concerned in the field of atomization powder preparation due to its high instantaneous temperature and high instantaneous speed. Generally, the plasma atomization equipment integrates three plasma torches for atomizing high-melting-point metal wires with a diameter of 3-8 mm, such as titanium alloy, tungsten, molybdenum, tantalum, niobium and other high-melting-point alloys. The powder prepared by the technology has the advantages of high sphericity, high purity, high flowability and concentrated powder particle size distribution, and is favored in the field of powder preparation.

[0003] However, the plasma atomization technology is not suitable for atomization powder preparation of low-melting-point metal alloys such as aluminum alloy, tin alloy and copper alloy due to its excessively high instantaneous temperature. The excessively high temperature can cause the low-melting-point metal to directly gasify and overflow in the melting process. Therefore, when atomizing the low-melting-point metal, only a lower power and a faster wire feeding speed can be used, which not only makes the production process difficult to control, but also makes the powder composition easy to be burned and difficult to ensure the stability of the composition and control the fine powder rate. Meanwhile, this production method has low efficiency and high cost compared with the traditional VIGA equipment, which is difficult for production enterprises to accept. SUMMARY

[0004] The purpose of the present application is to provide a high-energy high-speed plasma atomization multi-wire processing method to realize the plasma atomization of low-melting-point metal, ensure the high quality of the powder, improve the production efficiency and reduce the production cost.

[0005] To solve the above technical problems, the technical scheme adopted by the present application is as follows:

[0006] A high-energy high-speed plasma atomization multi-wire processing method for atomization powder preparation of low-melting-point alloy includes the following steps:

[0007] S1, synchronously and at the same speed, feeding 3 groups or more of low-melting-point alloy wires with a diameter of 3-6 mm through a feeding mechanism to make the multiple groups of wires intersect at the same intersection point;

[0008] S2, positioning the outlet of a single plasma torch at 2-5 mm above the wire intersection point, and overlapping the plasma torch ignition port and the wire intersection point in the vertical direction, starting the plasma torch, and using a high-energy dense plasma beam to melt the multiple groups of wires at the intersection point into a metal liquid column;

[0009] S3, making the metal liquid column freely fall onto a slant plate integrated ultrasonic rotating disc below, and setting the inclination angle of the rotating disc within a specified range;

[0010] S4, when the metal liquid column is at a set distance from the rotating disc, the first breaking of the vacuum is performed, then the high-speed rotation of the rotating disc is started and the ultrasonic vibrator at the bottom of the rotating disc is started, the ultrasonic vibrator transmits ultrasonic waves through a stainless steel conduit, the metal liquid column is broken for the second time by high-speed centrifugal force after contacting the rotating disc, and is refined under the action of ultrasonic vibration.

[0011] Preferably, in step S1, the low-melting-point alloy is an aluminum alloy, a magnesium alloy, a manganese alloy, a tin alloy or a copper alloy.

[0012] Preferably, in step S1, the number of groups of the wire material is 3-5 groups.

[0013] Preferably, in step S1, the synchronous and constant-speed feeding of the wire material is achieved by a feeding mechanism driven by a servo motor, and the feeding speed is matched with the power of the plasma torch.

[0014] Preferably, in step S2, the plasma beam generated by the plasma torch is a high-energy density plasma beam, which is used for rapidly melting multiple groups of wire materials.

[0015] Preferably, in step S3, the inclination angle of the inclined plate integrated ultrasonic rotating disc is specifically 3°, 4° or 5°.

[0016] Preferably, in step S4, the high-speed rotation of the rotating disc is synchronized with the start of the ultrasonic vibrator.

[0017] Preferably, in step S4, the set distance between the metal liquid column and the rotating disc is controlled to be 0.1-0.2mm, so as to ensure the effect of the first breaking of the vacuum.

[0018] Preferably, in step S4, the three-time breaking of the metal liquid is achieved by the first breaking of the vacuum, the second breaking and the ultrasonic vibration refinement.

[0019] Preferably, the method is performed in an equipment cavity in the shape of an extraction bottle, so as to provide sufficient rotating centrifugal distance.

[0020] Thanks to the use of the above technical solutions, the present application has the following beneficial effects compared with the prior art:

[0021] The application provides a high-energy high-speed plasma atomization multi-wire processing method, realizes plasma atomization of low-melting-point alloys, avoids the problem of gasification overflow of low-melting-point metals caused by excessively high temperature by reasonably setting the position of the intersection point of the plasma torch and the wire, and adopts a single-torch multi-wire mode, ensures the stability of the powder composition, and no macroscopic burning loss phenomenon occurs; the technical route of plasma atomization plus a rotating disc plus ultrasonic vibration is adopted to break the metal liquid column multiple times, improves the fine powder rate of the powder, and improves the cooling effect of the metal liquid drops, so that the sphericity of the powder is better and the hollow rate is lower; a single plasma torch simultaneously processes multiple groups of wires, improves the production efficiency under the premise of ensuring the atomization effect, reduces the production cost, and makes the technology more practical and economical in the field of low-melting-point alloy powder production; effectively solves the problem of existing plasma atomization technology in low-melting-point alloy processing, and has important popularization and application value. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the specific embodiments or the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0023] Figure 1 The flowchart of the high-energy high-speed plasma atomization multi-wire processing method of the present application. DETAILED DESCRIPTION

[0024] In order to make the person skilled in the art better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should be within the scope of protection of the present application.

[0025] It should be noted that the terms "first", "second" and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily limit to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0026] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "transverse", "longitudinal" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not intended to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0027] In addition, in addition to indicating the orientation or positional relationship, the above-mentioned partial terms can also be used to indicate other meanings, for example, the term "upper" can also be used to indicate a certain dependent relationship or connection relationship in some cases. For those skilled in the art, the specific meaning of these terms in the present application can be understood according to the specific situation.

[0028] In addition, the terms "mounting", "setting", "provided with", "connected", "connected", "sleeved" should be broadly understood. For example, it can be fixedly connected, detachably connected, or integrally constructed; it can be mechanically connected, or electrically connected; it can be directly connected, or indirectly connected through an intermediate medium, or internal communication between two devices, elements or components. For those skilled in the art, the specific meaning of the above-mentioned terms in the present application can be understood according to the specific situation.

[0029] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0030] Embodiment one

[0031] Please refer to Figure 1 The present application provides a high-energy high-speed plasma atomization multi-wire processing method for atomization powder of low melting point alloy, comprising the following steps:

[0032] S1, synchronously and at the same speed, 3 groups or more of low melting point alloy wire materials with a diameter of 3-6 mm are transported by a feeding mechanism, so that the multiple groups of wire materials intersect at the same intersection point;

[0033] The low melting point alloy is preferably aluminum alloy, magnesium alloy, manganese alloy, tin alloy or copper alloy; the number of groups of wire materials is further preferably 3-5 groups, so as to maximize the production efficiency on the premise of ensuring the atomization effect; the synchronous and same speed feeding of the wire materials is preferably realized by a feeding mechanism driven by a servo motor, and the feeding speed is matched and adjusted according to the power of the plasma torch, so as to ensure that the wire materials can be fully and stably melted when reaching the intersection point.

[0034] S2, positioning the outlet of the single plasma torch 2-5 mm above the wire intersection point, and the plasma torch ignition port overlaps the wire intersection point in the vertical direction, starting the plasma torch, and using the high-energy dense plasma beam generated thereby to melt the multiple groups of wires at the intersection point into a metal liquid column;

[0035] The single plasma torch is used to replace the traditional multi-torch design, and combined with the multi-wire convergence, the energy can be concentrated to efficiently melt the wires, while avoiding the problem of local temperature being too high caused by the energy superposition of the multi-torch; the characteristics of the high-energy dense plasma beam ensure the rapid and uniform melting of the multiple groups of wires.

[0036] S3, allowing the metal liquid column to freely fall to the inclined plate integrated ultrasonic rotating disc below, and the rotating disc is set to have an inclination angle within a specified range;

[0037] The inclination angle of the inclined plate integrated ultrasonic rotating disc is preferably 3°, 4° or 5°, and this angle range can effectively prevent powder particles from accumulating on the rotating disc, ensure the smooth falling of the powder, and avoid the problem of difficult powder taking.

[0038] S4, breaking the vacuum once when the metal liquid column is at a set distance from the rotating disc, and then starting the high-speed rotation of the rotating disc and the ultrasonic vibrator at the bottom of the rotating disc, the ultrasonic vibrator transmits ultrasonic waves through a stainless steel conduit, and the metal liquid column is broken again by the high-speed centrifugal force after contacting the rotating disc, and is refined under the action of ultrasonic vibration;

[0039] The set distance between the metal liquid column and the rotating disc is strictly controlled to be 0.1-0.2 mm, and this distance setting is the key to ensuring the effect of the first breaking of the vacuum, and can preliminarily break the metal liquid column; the high-speed rotation of the rotating disc and the starting of the ultrasonic vibrator are preferably synchronized to realize the synergistic effect of the breaking energy; through the above-mentioned first breaking of the vacuum, second breaking and ultrasonic vibration refining, the metal liquid is finally broken three times to ensure that the powder is sufficiently refined.

[0040] Further, the method is carried out in an extraction bottle-shaped device cavity, and the shape design provides sufficient space and distance for the breaking, cooling and centrifugal movement of the metal liquid droplets, which is beneficial to improve the sphericity and cooling effect of the powder.

[0041] Example Two

[0042] Preparation of aluminum alloy powder, the aluminum alloy powder is prepared by using the high-energy high-speed plasma atomization multi-wire processing method according to the present application, and the steps are as follows:

[0043] S1, select 4 groups of aluminum alloy wires (such as 6061 aluminum alloy) with a diameter of 5 mm, and synchronously and uniformly feed the wires through 4 sets of roller type feeding mechanisms driven by servo motors (the feeding speed is set to 25㎜ / s), and adjust the wire guide to make the 4 groups of wires meet at the same intersection point at the predetermined position.

[0044] S2, position the outlet of a single plasma torch (the model is selected as a non-transferred arc plasma torch with adjustable plasma arc power) 3 mm above the intersection point of the wires, ensure that the center of the ignition port of the plasma torch completely overlaps the intersection point of the wires in the vertical direction, start the plasma torch, and set the plasma power to 80 kW to generate a high-energy density plasma beam that precisely acts on the 4 groups of aluminum alloy wires at the intersection point to rapidly melt them into a continuous aluminum alloy liquid column.

[0045] S3, the aluminum alloy liquid column freely falls under the action of gravity to the inclined plate integrated ultrasonic rotating disc below, and the inclination angle of the rotating disc is set to 4°.

[0046] S4, when the aluminum alloy liquid column falls to a distance of 0.15 mm from the upper surface of the rotating disc, it is disturbed by the high-speed airflow around the rotating disc and its own gravity to break the space for the first time, and is initially broken into smaller droplets. Subsequently, the rotating disc is started to rotate at a high speed of 40000 r / min, and the ultrasonic vibrator at the bottom thereof is started (the vibration frequency is set to 30 kHz). The ultrasonic vibration is transmitted to the rotating disc through the stainless steel conduit. After the droplets broken by the first time contact the rotating disc, they are broken for the second time under the action of high-speed centrifugal force, and are further refined into micro-droplets under the high-frequency impact of ultrasonic vibration. These micro-droplets fly in the cavity shaped like an extraction bottle, rapidly cool and spheroidize, and finally form aluminum alloy powder which slides along the inclined rotating disc and enters the collection device below.

[0047] It is detected that the 6061 aluminum alloy powder prepared by the method of the embodiment has a sphericity of >96%, a fine powder rate (D50<30μm) of >80%, a hollow rate of <0.1%, and an oxygen content of <300ppm, all of which are better than those of the same type of powder prepared by the traditional VIGA method, and the production efficiency is 4 times that of the traditional plasma single-torch single-wire method, and the unit cost is reduced by about 40%.

[0048] Example Three

[0049] The tin alloy powder is prepared by a method similar to that of Example Two, and the main parameters are adjusted as follows:

[0050] Wires: 3 groups of Sn-5Sb alloy wires with a diameter of 4 mm;

[0051] Feeding speed: 30㎜ / s;

[0052] Plasma torch power: 60 kW, outlet distance from intersection point: 2 mm above

[0053] Rotating disc inclination angle: 3°, rotation speed 35000r / min;

[0054] Ultrasonic vibration frequency: 25kHz;

[0055] First broken distance: 0.1mm.

[0056] The tin alloy powder obtained finally has a sphericity of >96%, a fine powder rate of >80%, and meets the requirements of the electronic packaging field for high-performance tin-based welding powder, and the production efficiency is 3 times higher than that of the traditional method.

[0057] Compared with the prior art, the present application has the following beneficial effects:

[0058] Stable plasma atomization of low-melting-point alloy: the present application realizes the concentration and efficient use of plasma energy by adopting a single plasma torch with multiple groups of thin wires (3-6mm) for synchronous feeding, and optimizing the relative position of the plasma torch and the intersection point of the wires (2-5mm above the outlet, vertical overlap); compared with the traditional multi-torch high-power mode, the present application can realize sufficient melting of multiple groups of low-melting-point wires at a lower power, avoid metal gasification overflow and component burning loss caused by excessively high temperature, and ensure the stability of the powder composition.

[0059] Significant improvement of powder quality:

[0060] High fine powder rate and low hollow rate: through the three-breaking mechanism of "first breaking (at a distance of 0.1-0.2mm from the rotating disc) + secondary centrifugal breaking + ultrasonic vibration refinement", the metal liquid column is fully broken into small droplets, greatly improving the fine powder rate; at the same time, multiple breaking and rapid cooling reduce the gas wrapping inside the droplets, reducing the hollow rate of the powder.

[0061] High sphericity: the cavity in the shape of an extraction bottle provides sufficient cooling space, and the extraction bottle shape is conducive to avoiding powder adhesion on the tank, facilitating subsequent cleaning, combined with the centrifugal force of the high-speed rotating disc, the metal droplets rapidly spheroidize during flight due to surface tension, obtaining high-sphericity powder with excellent flowability.

[0062] Greatly improve production efficiency and reduce cost:

[0063] Three or more groups (preferably 3-5 groups) of wires are fed synchronously, and are melted simultaneously under the action of a single plasma torch; compared with the traditional single-torch single-wire mode, the metal processing amount per unit time is significantly increased, and the production efficiency is increased by more than 3 times.

[0064] The use of a single plasma torch reduces the energy consumption and maintenance cost of the equipment, and cooperates with efficient powder output, so that the production cost of unit powder is greatly reduced, and has the potential to compete with traditional VIGA equipment.

[0065] High process stability and controllability:

[0066] The feeding mechanism driven by servo motor ensures the synchronous feeding of multiple groups of wires at the same speed, ensuring the stability of the melting process.

[0067] The 3-5° inclination design of the rotating disc effectively solves the problem of powder accumulation, and in combination with the auxiliary unloading of ultrasonic vibration, ensures the continuous and stable progress of the production process.

[0068] Each process parameter (such as wire diameter, feeding speed, plasma torch power, rotating disc speed, ultrasonic frequency, distance parameter, etc.) can be accurately controlled according to the characteristics of different low-melting-point alloys, and has strong adaptability.

[0069] Finally, it should be noted that the above is only the preferred embodiment of the present application and is not intended to limit the present application, although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments or make equivalent replacements for some of the technical features, and any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included within the protection scope of the present application.

Claims

1. A high-energy, high-speed plasma atomization multi-wire processing method for atomizing and powdering low-melting-point alloys, characterized in that, Includes the following steps: S1, three or more sets of low melting point alloy wires with a diameter of 3-6mm are fed synchronously and at the same speed through the feeding mechanism, so that multiple sets of wires converge at the same intersection point; S2, Position the outlet of a single plasma torch 2-5mm above the junction of the wires, and make the ignition port of the plasma torch overlap with the junction of the wires in the vertical direction. Start the plasma torch and use a high-energy-density plasma beam to melt multiple sets of wires at the junction into a liquid metal column. S3, allowing the metal liquid column to fall freely onto the inclined plate integrated ultrasonic rotating disk directly below, the tilt angle of the rotating disk being set within a specified range; S4. When the metal liquid column is at a set distance from the rotating disk, it is broken once. Then, the rotating disk is started to rotate at high speed and the ultrasonic vibrator at its bottom is started. The ultrasonic vibrator transmits ultrasonic waves through a stainless steel conduit. After the metal liquid column comes into contact with the rotating disk, it is broken up again by high-speed centrifugal force. At the same time, it is refined under the action of ultrasonic vibration.

2. The high-energy, high-speed plasma atomization multi-filament processing method according to claim 1, characterized in that, In step S1, the low-melting-point alloy is an aluminum alloy, magnesium alloy, manganese alloy, tin alloy, or copper alloy.

3. The high-energy, high-speed plasma atomization multi-filament processing method according to claim 1, characterized in that, In step S1, the number of groups of filaments is 3-5.

4. The high-energy, high-speed plasma atomization multi-filament processing method according to claim 1, characterized in that, In step S1, the synchronous and same-speed feeding of the filament is achieved by a feeding mechanism driven by a servo motor, and the feeding speed is matched with the power of the plasma torch.

5. The high-energy, high-speed plasma atomization multi-filament processing method according to claim 1, characterized in that, In step S2, the plasma beam generated by the plasma torch is a high-energy-density plasma beam, which is used to rapidly melt multiple sets of wires.

6. The high-energy, high-speed plasma atomization multi-filament processing method according to claim 1, characterized in that, In step S3, the tilt angle of the inclined plate integrated ultrasonic rotary disk is specifically 3°, 4° or 5°.

7. The high-energy, high-speed plasma atomization multi-filament processing method according to claim 1, characterized in that, In step S4, the high-speed rotation of the rotating disk is synchronized with the start-up of the ultrasonic vibrator.

8. The high-energy, high-speed plasma atomization multi-filament processing method according to claim 1, characterized in that, In step S4, the set distance between the liquid metal column and the rotating disk is controlled at 0.1-0.2 mm to ensure a single air-breaking effect.

9. The high-energy, high-speed plasma atomization multi-filament processing method according to claim 1, characterized in that, In step S4, the molten metal is broken up in three stages through primary cavitation, secondary crushing, and ultrasonic vibration refinement.

10. The high-energy, high-speed plasma atomization multi-filament processing method according to claim 1, characterized in that, The method is carried out in an extraction bottle-shaped device cavity to provide sufficient rotational centrifugation distance.

Images