A method of recycling a titanium alloy coarse-grained powder EIGA atomized

Abstract

The application discloses a method for recycling coarse particle powder of titanium alloy by EIGA atomization, and aims to solve the technical problems of the existing titanium alloy coarse particle powder recycling process, such as complexity, easy contamination of the melt, low conversion rate of fine powder and inability of industrial batch production; the coarse powder of titanium alloy with a particle size greater than 53 microns by-produced in the gas atomization powder production is used as raw material, and the raw material is sequentially subjected to pretreatment, closed controllable powder feeding, sectional induction melting, controllable flow guiding and atomization, spheroidization solidification and grading collection steps; through real-time dynamic matching of the powder feeding rate and the melting rate, combined with the sectional induction heating process of the yttrium oxide sleeve, the coarse powder is directly converted into high-value-added titanium alloy fine powder; the process flow is short, and 24h continuous industrial production can be realized; the oxygen content of the prepared regenerated powder is less than or equal to 800ppm, the total yield of the high-value-added powder is greater than or equal to 65%, and the powder performance is fully suitable for the high-end powder demand of additive manufacturing and metal injection molding.

Description

Technical Field

[0001] This invention relates to the field of titanium alloy powder preparation and recycling technology, specifically to a method for recovering coarse titanium alloy powder through EIGA atomization. Background Technology

[0002] Titanium and titanium alloys, with their high specific strength, excellent corrosion resistance, good biocompatibility, and high-temperature resistance, are widely used in aerospace, biomedicine, and 3C electronics fields. Among these, additive manufacturing (3D printing) and metal injection molding (MIM) are the core application scenarios for titanium alloy powders. Currently, the mainstream process for preparing titanium alloy powders for additive manufacturing is Electrode Induction Gas Atomization (EIGA). This process has advantages such as no crucible contamination, high powder purity, and good sphericity, making it suitable for the performance requirements of high-end additive manufacturing.

[0003] In the industrial production of titanium alloy powder, gas atomization processes such as EIGA have inherent particle size distribution characteristics, inevitably producing a large amount of coarse powder byproducts with a particle size >53μm. Downstream high-end applications exhibit significant particle size-specific demand characteristics: the 0-20μm fine powder segment mainly supplies the metal injection molding market, while the 15-53μm medium-fine powder segment is highly compatible with additive manufacturing technologies such as selective laser melting (SLM). Both types of high-value-added powders have long been in a state of strong demand and tight supply. However, the coarse powder segment >53μm faces the dilemma of overcapacity and a single channel for consumption. The large backlog of coarse powder not only increases the storage and operating costs of powder manufacturing enterprises, but also restricts the overall capacity release of enterprises, and even affects the stable supply and price system of high-value-added fine powder segments, resulting in a serious waste of titanium resources.

[0004] Currently, existing solutions for recycling titanium alloy scrap / powder have many shortcomings:

[0005] 1. Patent CN202511600116.3 discloses a titanium alloy coarse / waste material treatment scheme, which adopts ultrasonic atomization powder making process. However, this process has an unavoidable technical bottleneck: there is a dilemma in the selection of ultrasonic disk material. Materials such as aluminum and titanium with high vibration speed have low melting points and are easily corroded when in contact with high-temperature titanium melt, causing titanium melt pollution and affecting the performance of regenerated powder. On the other hand, high-melting-point inert materials such as tungsten, molybdenum, tantalum, and niobium have high density and cannot achieve efficient crushing of titanium melt, resulting in poor atomization effect, extremely low fine powder yield, and low single furnace capacity of ultrasonic atomization, which cannot meet the needs of industrial mass production.

[0006] 2. Existing titanium alloy waste recycling processes, such as the solutions disclosed in patents CN118106326A and CN119020613A, are mostly for titanium shavings and blocky titanium waste. They require multiple processes such as crushing, alkaline washing, briquetting, and welding into electrode rods, followed by vacuum self-consumable melting or gas atomization powdering. The process is long and costly, and cannot be directly adapted to the recycling of coarse titanium alloy powder. Moreover, multiple processing steps can easily lead to an increase in the oxygen content of the powder, which cannot meet the high purity requirements of powder used in additive manufacturing.

[0007] 3. Existing titanium alloy waste powder recycling technologies, such as the solutions disclosed in patents CN118421931A and CN110666178B, mostly focus on surface deoxygenation and sieving purification of powder. They can only achieve simple reuse of waste powder and cannot convert coarse powder into high-value-added fine powder products, thus failing to solve the structural surplus problem of coarse powder.

[0008] Therefore, developing a recycling powder production method that has a short process flow, no secondary pollution, continuous production capability, and can efficiently convert titanium alloy coarse powder into high-value-added fine powder has become a technical problem that the industry urgently needs to solve. Summary of the Invention

[0009] The purpose of this invention is to provide a method for recovering coarse titanium alloy powder through EIGA atomization, which solves the problems of low utilization rate of existing coarse titanium alloy powder, complex recovery process, easy melt contamination, low production capacity, and inability to convert it into high-value-added fine powder in batches. This method achieves low-cost, high-efficiency, and high-purity recycling of coarse titanium alloy powder, thereby enhancing the utilization value of titanium resources across all particle sizes.

[0010] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0011] A method for recovering EIGA atomized coarse titanium alloy powder includes the following steps:

[0012] S1, Raw material pretreatment: Select titanium alloy coarse particles with a particle size >53μm as raw material from the by-product of gas atomization powder making, and carry out impurity removal and drying treatment under inert gas protection to obtain pretreated titanium alloy coarse powder.

[0013] S2, Closed-loop controllable powder feeding: The pretreated titanium alloy coarse powder is fed into a special powder feeding device with vacuum-argon protection. High-purity argon is used as the conveying medium. The feeding host of the powder feeding device and the powerful pump work together to continuously feed the titanium alloy coarse powder into the yttrium oxide melting sleeve of the EIGA equipment at a stable rate. During the conveying process, the powder feeding rate is dynamically matched with the melting rate of the subsequent melting process in real time.

[0014] S3, Segmented Induction Melting: Medium-frequency induction coils and high-frequency induction coils are arranged vertically on the outside of the yttrium oxide melting sleeve. First, the titanium alloy coarse powder is preheated by the medium-frequency induction coil, so that the powder is heated to 700~1300℃ to achieve pre-sintering and softening. Then, the preheated powder is induction melted by the high-frequency induction coil, so that the titanium alloy coarse powder is completely melted into a uniform molten titanium liquid. The inert gas positive pressure protection is maintained throughout the melting process.

[0015] S4, Controllable flow guidance and atomization: After a stable titanium liquid droplet is observed to emerge from the bottom of the yttrium oxide melting sleeve, the plugging device at the bottom of the sleeve is activated, allowing the molten titanium liquid to form a continuous and stable liquid flow that falls vertically into the atomization zone. High-purity inert gas is used as the atomization medium, and the titanium liquid flow is broken up by supersonic gas atomization through the EIGA atomization nozzle to obtain micron-sized titanium alloy droplets.

[0016] S5, Spheroidization, Solidification and Classification Collection: The broken titanium alloy droplets are rapidly spheroidized by surface tension in an inert gas atmosphere and then rapidly solidified in the atomization tower to form spherical titanium alloy powder. The powder is then collected in a graded manner through the main collection tank, cyclone separator and filter to obtain recycled titanium alloy powder of different particle sizes.

[0017] In a preferred embodiment, in step S1, the titanium alloy coarse powder is any one of the additive manufacturing gas atomization by-product coarse powders from grades TC4, TA15, and TC11, and the oxygen increment of the powder after pretreatment is ≤100ppm and the moisture content is ≤0.05wt%.

[0018] In a preferred embodiment, in step S2, the single loading capacity of the material chamber of the dedicated powder feeding device is ≥100Kg, the feeding host adopts a rotary valve type or Venturi type powder feeder, the powerful pump adopts a screw pump or Venturi pump, the purity of the conveying medium high-purity argon gas is ≥99.999%, and the gas pressure is adjusted to 0.2~0.8MPa and the conveying flow rate is 5~15m³ / h by the controller during the conveying process.

[0019] In a preferred embodiment, in step S2, the dynamic matching range between the powder feeding rate and the melting rate is 5~30Kg / h, and the fluctuation range of the powder feeding rate is ≤±5%. When the temperature of the molten pool exceeds the liquidus temperature of the titanium alloy by 100~150℃, the powder feeding rate is increased; when the temperature of the molten pool is lower than the liquidus temperature of the titanium alloy by 50℃, the powder feeding rate is decreased.

[0020] In a preferred embodiment, in step S3, the yttrium oxide melting sleeve is made of sintered yttrium oxide material, the single storage capacity inside the sleeve is 30~50Kg, the heating frequency of the medium frequency induction coil is 8~15kHz, the heating frequency of the high frequency induction coil is 30~60kHz, and the temperature of the molten pool is controlled at 1680~1750℃ during the melting process.

[0021] In a preferred solution, in step S3, the plug body of the plug removal device is made of any one of tungsten, molybdenum, tantalum, niobium and their alloys. The diameter of the plug body is smaller than the diameter of the through hole at the bottom of the yttrium oxide melting sleeve. During the plug removal operation, it first moves downward along the axial direction of the sleeve by 20 - 50 mm, and then moves horizontally to avoid long-term contact between the plug body and the molten titanium liquid, thus preventing contamination.

[0022] In a preferred solution, in step S4, the atomizing nozzle adopts an annular hole type or a close-coupling type structure. The atomizing medium is argon or helium with a purity ≥ 99.999%, the atomizing pressure is 3 - 8 MPa, and the gas outlet velocity is 2 - 4 Mach.

[0023] In a preferred solution, throughout the whole process from step S2 to S5, the system always maintains a positive pressure of inert gas, with the pressure value being 0.02 - 0.05 MPa. The oxygen content in the system is controlled ≤ 50 ppm through at least 2 vacuum pumping - argon filling cycles, and the oxygen content of the finally prepared recycled titanium alloy powder is ≤ 800 ppm.

[0024] In a preferred solution, in step S2, through the continuous feeding system and the vacuum pumping - gas filling system supporting the special powder feeding device, continuous feeding without stopping the machine is achieved, and the continuous production duration of a single batch is ≥ 24 h.

[0025] In a preferred solution, in step S5, the proportion of powder in the particle size range of 15 - 53 μm obtained after classification and collection is ≥ 45%, the proportion of powder in the particle size range of 0 - 20 μm is ≥ 20%, the sphericity of the powder is ≥ 95%, and the Hall flow rate is ≤ 28 s / 50 g.

[0026] Due to the application of the above technical solutions, the beneficial effects of this application compared with the prior art are as follows:

[0027] 1. Realize the high - value conversion of titanium alloy coarse powder and solve the structural contradictions in the industry. The present invention can directly convert titanium alloy coarse powder with a particle size > 53 μm produced as a by - product of gas atomization into medium - fine powder with a particle size of 15 - 53 μm for additive manufacturing and fine powder with a particle size of 0 - 20 μm for MIM through the EIGA atomization process. The recovery rate of high - value powder is ≥ 65%, completely solving the problems of overcapacity and resource waste of coarse powder, greatly reducing the storage pressure of powder - making enterprises, and improving the utilization efficiency of titanium resources in all particle sizes and the profitability of enterprises.

[0028] 2. The process flow is short, continuous industrial production can be achieved, and the production cost is low. The present invention abandons the complex processes of traditional titanium scrap recycling, such as crushing, briquetting, and welding electrode rods. It directly sends the coarse powder into the melting sleeve through a closed powder feeding system for atomization powder making, without requiring structural modification of the existing EIGA equipment. It can achieve continuous production without stopping the machine for 24 h, and the production efficiency is increased by more than 10 times compared with the ultrasonic atomization process, greatly reducing the recycling cost.

[0029] 3. Effectively avoids melt contamination, resulting in high-purity and high-performance recycled powder. This invention uses a sintered yttrium oxide melting sleeve, which exhibits excellent thermodynamic stability with molten titanium, eliminating the risk of crucible contamination. The entire process is protected by high-purity inert gas, ensuring precise control of the system's oxygen content. The oxygen content of the recycled powder can be stably controlled below 800 ppm, with high-quality products reaching below 500 ppm. Simultaneously, segmented induction melting ensures complete powder melting and uniform composition. The final powder produced has a sphericity ≥95%, and its flowability, bulk density, and other core indicators fully meet the high-end application requirements of additive manufacturing and metal injection molding.

[0030] 4. Strong process stability and wide adaptability. This invention effectively avoids problems such as unmelted raw material accumulation, unstable molten pool, and atomization interruption by real-time dynamic matching of powder feeding rate and melting rate, combined with segmented induction heating process. The atomization process is continuous and stable. It can be adapted to the recycling of mainstream titanium alloy coarse powders such as TC4, TA15, and TC11, and has extremely strong industrial promotion value. Attached Figure Description

[0031] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of a method for recovering coarse titanium alloy powder from EIGA atomization according to the present invention. Detailed Implementation

[0033] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0034] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0035] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing the invention and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0036] Furthermore, in addition to indicating direction or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in certain situations to indicate a dependency or connection. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0037] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linking," and "socketing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0038] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0039] Example 1

[0040] Please see Figure 1 This embodiment provides a method for recovering EIGA atomized TC4 titanium alloy coarse powder, and the specific steps are as follows:

[0041] S1, Raw material pretreatment: TC4 titanium alloy coarse powder with a particle size >53μm, which is a by-product of EIGA gas atomization powdering, is selected as raw material. Under argon protection, large particle agglomerates and impurities are removed by vibrating screen. The powder is then placed in a vacuum drying oven and dried at 150℃ for 4 hours to obtain pretreated titanium alloy coarse powder. Its oxygen increment is 80ppm and its moisture content is 0.03wt%.

[0042] S2, Closed-loop Controlled Powder Feeding: Pretreated titanium alloy coarse powder is fed into a dedicated powder feeding device with vacuum-argon purging protection. The material chamber is loaded with 100 kg at a time. High-purity argon gas with a purity of 99.999% is used as the conveying medium. A rotary valve type feeding host and a screw type high-power pump are used for coordinated conveying. The conveying gas pressure is controlled by the controller to be 0.5 MPa and the conveying flow rate is 10 m³ / h. The titanium alloy coarse powder is continuously conveyed to the yttrium oxide melting sleeve of the EIGA equipment at a stable rate of 15 kg / h. During the conveying process, the temperature of the molten pool is collected in real time, and the powder feeding rate is dynamically matched with the melting rate. The fluctuation range of the powder feeding rate is controlled within ±3%.

[0043] S3, Segmented Induction Melting: The yttrium oxide melting sleeve is made of sintered yttrium oxide material. The sleeve has a single material storage capacity of 40 kg. Medium-frequency induction coils and high-frequency induction coils are arranged vertically on the outside of the sleeve. First, the titanium alloy coarse powder is preheated by the medium-frequency induction coil (heating frequency 10 kHz) to raise the powder temperature to 1000℃ to achieve pre-sintering and softening. Then, the preheated powder is induction melted by the high-frequency induction coil (heating frequency 40 kHz). The temperature of the molten pool is controlled at 1700℃ so that the titanium alloy coarse powder is completely melted into a uniform molten titanium liquid. Argon gas positive pressure protection is maintained throughout the melting process.

[0044] S4, Controllable Flow Guidance and Atomization: After observing stable titanium liquid droplets at the bottom of the yttrium oxide melting sleeve, operate the tungsten plugging device at the bottom of the sleeve, first moving it downwards 30mm along the sleeve axis, and then moving it horizontally to allow the molten titanium liquid to form a continuous and stable liquid flow that falls vertically into the atomization zone; use an annular atomizing nozzle, with high-purity argon gas of 99.999% purity as the atomizing medium, adjust the atomization pressure to 5MPa, and the gas outlet velocity to Mach 3 to perform supersonic gas atomization and breakup of the titanium liquid flow to obtain micron-sized titanium alloy droplets.

[0045] S5, Spheroidization, Solidification and Classification Collection: The broken titanium alloy droplets are rapidly spheroidized by surface tension in an argon atmosphere and then rapidly solidified in the atomization tower to form spherical titanium alloy powder. The powder is then classified and collected through the bottom main collection tank, the rear cyclone separator and the bag filter to obtain regenerated TC4 titanium alloy powder of different particle sizes.

[0046] In this embodiment, the system maintains a positive argon pressure of 0.03 MPa throughout the entire process. By controlling the oxygen content in the system to be ≤30 ppm through three vacuum-argon-filling cycles, the oxygen content of the final regenerated powder is 580 ppm. The proportion of powder for 15~53 μm additive manufacturing is 48%, the proportion of powder for 0~20 μm MIM is 22%, the powder sphericity is 97%, and the Hall flow rate is 25 s / 50 g, which fully meets the requirements for additive manufacturing and metal injection molding.

[0047] Example 2

[0048] This embodiment provides a method for recovering EIGA atomized coarse TA15 titanium alloy powder, and the specific steps are as follows:

[0049] S1, Raw material pretreatment: TA15 titanium alloy coarse powder with a particle size >53μm, which is a by-product of EIGA gas atomization powdering, is selected as raw material. Impurities are removed by vibrating screen under argon protection. The powder is then placed in a vacuum drying oven and dried at 180℃ for 3 hours to obtain pretreated titanium alloy coarse powder. Its oxygen increment is 90ppm and its moisture content is 0.02wt%.

[0050] S2, Closed-loop Controlled Powder Feeding: Pretreated titanium alloy coarse powder is fed into a dedicated powder feeding device with vacuum-argon filling protection. The material chamber is loaded with 120 kg at a time, using high-purity argon gas (99.999%) as the conveying medium. A Venturi-type feeding host and a Venturi-type high-power pump are used for coordinated conveying. The conveying gas pressure is controlled at 0.6 MPa and the conveying flow rate is 12 m³ / h by the controller. The titanium alloy coarse powder is continuously conveyed to the yttrium oxide melting sleeve of the EIGA equipment at a stable rate of 20 kg / h. During the conveying process, the temperature of the molten pool is collected in real time, and the powder feeding rate is dynamically matched with the melting rate. The fluctuation range of the powder feeding rate is controlled within ±4%. Through the matching continuous feeding system and vacuum-filling system, continuous feeding without stopping the machine can be achieved, and the continuous production time of a single batch is 24 hours.

[0051] S3, Segmented Induction Melting: The yttrium oxide melting sleeve is made of sintered yttrium oxide material. The sleeve has a single material storage capacity of 50 kg. Medium-frequency induction coils and high-frequency induction coils are arranged vertically on the outside of the sleeve. First, the titanium alloy coarse powder is preheated by the medium-frequency induction coil (heating frequency 12 kHz) to raise the powder temperature to 1200℃ to achieve pre-sintering and softening. Then, the preheated powder is induction melted by the high-frequency induction coil (heating frequency 50 kHz). The temperature of the molten pool is controlled at 1720℃ so that the titanium alloy coarse powder is completely melted into a uniform molten titanium liquid. Argon gas positive pressure protection is maintained throughout the melting process.

[0052] S4, Controllable Flow Guidance and Atomization: After observing stable titanium liquid droplets at the bottom of the yttrium oxide melting sleeve, operate the molybdenum plugging device at the bottom of the sleeve, first moving it downwards 40mm along the sleeve axis, and then moving it horizontally to allow the molten titanium liquid to form a continuous and stable liquid flow that falls vertically into the atomization zone; use a tightly coupled atomizing nozzle, with high-purity argon gas of 99.999% purity as the atomizing medium, adjust the atomization pressure to 6MPa, and the gas outlet velocity to Mach 3.5, to perform supersonic gas atomization and breakup of the titanium liquid flow to obtain micron-sized titanium alloy droplets.

[0053] S5, Spheroidization, Solidification and Classification Collection: The broken titanium alloy droplets are rapidly spheroidized by surface tension in an argon atmosphere and then rapidly solidified in the atomization tower to form spherical titanium alloy powder. The powder is then classified and collected through the bottom main collection tank, the rear cyclone separator and the bag filter to obtain regenerated TA15 titanium alloy powder of different particle sizes.

[0054] In this embodiment, the system maintains a positive argon pressure of 0.04 MPa throughout the entire process. By controlling the oxygen content in the system to be ≤25 ppm through three vacuum-argon-filling cycles, the oxygen content of the final regenerated powder is 620 ppm. The proportion of 15~53 μm additive manufacturing powder is 46%, the proportion of 0~20 μm MIM powder is 21%, the powder sphericity is 96%, and the Hall flow rate is 26 s / 50 g, which meets the aerospace-grade additive manufacturing powder standard.

[0055] Example 3

[0056] This embodiment provides a method for recovering EIGA atomized TC11 titanium alloy coarse-particle powder, the specific steps of which are as follows:

[0057] S1, Raw material pretreatment: TC11 titanium alloy coarse powder with a particle size >53μm, which is a by-product of EIGA gas atomization powdering, is selected as raw material. It is purified under argon protection and dried in a vacuum drying oven at 160℃ for 3.5h to obtain pretreated titanium alloy coarse powder with an oxygen increase of 75ppm and a moisture content of 0.04wt%.

[0058] S2, Closed-loop controllable powder feeding: Pretreated titanium alloy coarse powder is fed into a special powder feeding device. The material chamber is loaded with 150Kg at a time. 99.999% high-purity argon is used as the conveying medium. The rotary valve feeding host is equipped with a screw pump. The conveying pressure is 0.3MPa, the conveying flow rate is 8m³ / h, the powder feeding rate is 10Kg / h, and the melting rate is matched in real time with a fluctuation range of ≤±5%.

[0059] S3, segmented induction melting: yttrium oxide melting sleeve with a single storage capacity of 30Kg, medium frequency induction coil heating frequency of 8kHz, preheating temperature of 800℃; high frequency induction coil heating frequency of 35kHz, molten pool temperature controlled at 1690℃, with inert gas positive pressure protection throughout the process.

[0060] S4, Controllable flow guidance and atomization: After the droplet has stabilized, operate the tantalum alloy plug removal device, first move it axially downward by 25mm, and then move it horizontally away; use an annular nozzle, the atomizing medium is 99.999% high-purity helium, the atomization pressure is 4MPa, the outlet speed is 2.5Mach, and gas atomization and breakup are performed.

[0061] S5, Spheroidization and Solidification and Classification Collection: After the droplets spheroidize and solidify, they are collected in stages to obtain regenerated TC11 titanium alloy powder.

[0062] In this embodiment, the system maintains a positive argon pressure of 0.025 MPa throughout the entire process, the system oxygen content is ≤40 ppm, the final regenerated powder oxygen content is 550 ppm, the proportion of 15~53 μm powder is 47%, the proportion of 0~20 μm powder is 23%, the sphericity is 96.5%, and the Hall flow rate is 26 s / 50 g.

[0063] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of recycling a titanium alloy coarse-grained powder EIGA atomized, characterized in that, Includes the following steps: S1, Raw material pretreatment: Select titanium alloy coarse particles with a particle size >53μm as raw material from the by-product of gas atomization powder making, and carry out impurity removal and drying treatment under inert gas protection to obtain pretreated titanium alloy coarse powder. S2, Closed-loop Controlled Powder Feeding: Pretreated titanium alloy coarse powder is fed into a dedicated powder feeding device with vacuum-argon protection. High-purity argon is used as the conveying medium. The powder feeding host and powerful pump work together to continuously feed the titanium alloy coarse powder into the yttrium oxide melting sleeve of the EIGA equipment at a stable rate. During the conveying process, the powder feeding rate is dynamically matched with the melting rate of the subsequent melting process in real time. The dynamic matching range between the powder feeding rate and the melting rate is 5~30Kg / h, and the fluctuation range of the powder feeding rate is ≤±5%. When the temperature of the molten pool exceeds the liquidus temperature of the titanium alloy by 100~150℃, the powder feeding rate is increased. When the temperature of the molten pool is lower than the liquidus temperature of the titanium alloy by 50℃, the powder feeding rate is decreased. S3, Segmented Induction Melting: Medium-frequency induction coils and high-frequency induction coils are arranged vertically on the outside of the yttrium oxide melting sleeve. First, the titanium alloy coarse powder is preheated by the medium-frequency induction coil, so that the powder is heated to 700~1300℃ to achieve pre-sintering and softening. Then, the preheated powder is induction melted by the high-frequency induction coil, so that the titanium alloy coarse powder is completely melted into a uniform molten titanium liquid. The inert gas positive pressure protection is maintained throughout the melting process. The heating frequency of the medium-frequency induction coil is 8~15kHz, and the heating frequency of the high-frequency induction coil is 30~60kHz. S4, Controllable flow guidance and atomization: After a stable titanium liquid droplet is observed to emerge from the bottom of the yttrium oxide melting sleeve, the plug removal device at the bottom of the sleeve is activated. The plug removal operation first moves downward 20~50mm along the sleeve axis, and then moves horizontally to allow the molten titanium liquid to form a continuous and stable liquid flow that falls vertically into the atomization zone. High-purity inert gas is used as the atomization medium, and the titanium liquid flow is atomized and broken by supersonic gas atomization through the EIGA atomization nozzle to obtain micron-sized titanium alloy droplets. S5, Spheroidization, Solidification and Classification Collection: The broken titanium alloy droplets are rapidly spheroidized by surface tension in an inert gas atmosphere and then rapidly solidified in the atomization tower to form spherical titanium alloy powder. The powder is then collected in a graded manner through the main collection tank, cyclone separator and filter to obtain recycled titanium alloy powder of different particle sizes.

2. The method for recovering EIGA atomized titanium alloy coarse particle powder according to claim 1, characterized in that, In step S1, the titanium alloy coarse powder is any one of the additive manufacturing gas atomization by-product coarse powders from grades TC4, TA15, and TC11. After pretreatment, the oxygen increment of the powder is ≤100ppm and the moisture content is ≤0.05wt%.

3. The method for recovering EIGA atomized titanium alloy coarse particle powder according to claim 1, characterized in that, In step S2, the single loading capacity of the material chamber of the special powder feeding device is ≥100Kg. The main feeding device adopts a rotary valve type or Venturi type powder feeder. The powerful pump adopts a screw pump or Venturi pump. The purity of the conveying medium, high-purity argon gas, is ≥99.999%. During the conveying process, the gas pressure is adjusted to 0.2~0.8MPa by the controller, and the conveying flow rate is 5~15m³ / h.

4. The method for recovering EIGA atomized titanium alloy coarse particle powder according to claim 1, characterized in that, In step S3, the yttrium oxide melting sleeve is made of sintered yttrium oxide material, and the single storage capacity inside the sleeve is 30~50Kg. During the melting process, the temperature of the molten pool is controlled at 1680~1750℃.

5. The method for recovering coarse titanium alloy powder from EIGA atomization according to claim 1, characterized in that, In step S3, the plug body of the plug removal device is made of any one of tungsten, molybdenum, tantalum, niobium and their alloys, and the diameter of the plug body is smaller than the diameter of the flow hole at the bottom of the yttrium oxide melting sleeve.

6. The method for recovering EIGA atomized titanium alloy coarse particle powder according to claim 1, characterized in that, In step S4, the atomizing nozzle adopts an annular or tightly coupled structure, the atomizing medium is argon or helium with a purity ≥99.999%, the atomizing pressure is 3~8MPa, and the gas outlet velocity is 2~4Mach.

7. The method for recovering coarse titanium alloy powder from EIGA atomization according to claim 1, characterized in that, Throughout steps S2 to S5, the system maintains a positive pressure of inert gas with a pressure value of 0.02~0.05MPa. The oxygen content in the system is controlled to be ≤50ppm through at least two vacuum-argon-filling cycles, and the oxygen content of the finally prepared recycled titanium alloy powder is ≤800ppm.

8. The method for recovering EIGA atomized titanium alloy coarse particle powder according to claim 1, characterized in that, In step S2, continuous feeding without stopping is achieved through the continuous feeding system and vacuum-gas-filling system matched with the dedicated powder feeding device, and the continuous production time of a single batch is ≥24h.

9. The method for recovering coarse titanium alloy powder from EIGA atomization according to claim 1, characterized in that, In step S5, the proportion of powder with a particle size of 15~53μm after graded collection is ≥45%, the proportion of powder with a particle size of 0~20μm is ≥20%, the sphericity of the powder is ≥95%, and the Hall flow rate is ≤28s / 50g.

Images