A device for separating non-metallic inclusions in high-temperature alloy powder by water elutriation

Abstract

The utility model relates to the field of inclusion analysis of high-temperature alloy powder, in particular to a device for separating nonmetallic inclusions in high-temperature alloy powder by water washing method. The utility model takes stokes sedimentation formula as principle, designs a device for separating nonmetallic inclusions in high-temperature alloy powder by water washing method. By designing the water inlet and outlet pipes with different diameters, the fluid flow rate in the screening pipe is different, thereby realizing the separation of nonmetallic inclusions with different densities and sizes in high-temperature alloy powder.

Description

Technical Field

[0001] This utility model relates to the field of inclusion analysis in high-temperature alloy powders, specifically to a device for separating non-metallic inclusions in high-temperature alloy powders by water washing. Background Technology

[0002] High-temperature alloy powders have been increasingly widely used in recent years, primarily as raw materials for various additive manufacturing devices. During the preparation of high-temperature alloy powders, non-metallic inclusions may be introduced due to the raw materials or the preparation process. These inclusions directly affect the properties of the high-temperature alloy powder, thereby influencing the microstructure, performance, and other indicators of the additive manufacturing devices. Therefore, analyzing inclusions in high-temperature alloy powders is particularly important.

[0003] Conventional methods for separating inclusions in high-temperature alloy powders include electrostatic separation, water washing, and stepwise acid separation. Electrostatic separation involves complex equipment and parameter settings, and its effectiveness is limited for inclusions with similar potentials to the substrate. While existing water washing equipment can separate metal powder from non-metallic inclusions, its separation efficiency is low and incomplete for small, irregularly shaped inclusions. Stepwise acid separation involves preparing solutions of varying pH and density to dissolve the metal powder and float the non-metallic inclusions. This method is environmentally unfriendly, requires different solutions for different alloy powder compositions, and is complex and has poor repeatability. Summary of the Invention

[0004] To address the problems in the existing technology, this utility model designs a device for separating non-metallic inclusions in high-temperature alloy powder by water washing, thereby improving the efficiency and accuracy of inclusion separation in high-temperature alloy powder.

[0005] This invention is based on the concept of gravity separation and uses Stokes' particle settling equation as the principle for device design. Stokes' particle settling equation is a classic formula describing the relationship between the settling velocity and the properties of the particles and the fluid when small particles undergo uniform settling motion in a viscous fluid. When particles settle in a viscous fluid under the action of gravity or centrifugal force and eventually reach uniform motion, i.e., gravity, buoyancy, and viscous resistance are in balance, their settling velocity v can be expressed as:

[0006] The physical meaning of each parameter is as follows: r: Particle radius (unit: m); ρ p Particle density is measured in kg / m³. ρ f Fluid density unit: kg / m³; g: Gravitational acceleration is approximately 9.8 m / s²; η: Dynamic viscosity of fluid, unit: Pa·s or kg / (m·s).

[0007] According to Stokes' theorem, the settling velocity of particulate matter is positively correlated with its density and radius, and the density of high-temperature alloys is generally 8~9.5 g / cm³. 3 The density of inclusions, represented by alumina-based non-metallic inclusions, is generally around 4 g / cm³, showing a significant difference between the two. Therefore, theoretically, the substrate and inclusions can be separated by controlling the flow rate of the fluid medium. When the particle size is the same, its density will be used as a condition for sieving different types of particles; when the particle density is the same, its size will be used as a sieving condition.

[0008] When the flow velocity of the fluid medium is greater than the settling velocity of the particles being screened, the particles will move upward and leave the screening component. When the flow velocity of the fluid medium is less than the settling velocity of the particles being screened, the particles will move downward and remain in the screening component.

[0009] Based on the above analysis, a tiered screening tube is designed. The screening tubes have the same size and volume, but the diameter of the discharge pipe increases progressively. This allows the discharge pipe velocity of the fluid in each screening tube to decrease progressively while the overall influent flow rate of the system remains stable, thereby completing the screening and separation of particles of different sizes and densities.

[0010] To ensure that the fluid medium does not react with the particles being screened and that there are no other particles in the medium interfering with the screening system, distilled water or deionized water is selected as the fluid medium in this system.

[0011] To ensure the screening effect, the powder sample to be tested should be prepared into a mixture, and the solid-liquid ratio of the mixture should be set according to the screening effect.

[0012] The technical solution of this utility model is as follows: This utility model discloses a device for separating non-metallic inclusions in high-temperature alloy powder by water washing, comprising a water pump, a mixing tank, multiple graded sieve tubes and a collection tank, and a water pipe system connecting these components; the water pipe system includes a system water supply pipe, a system lower water inlet pipe, and water inlet pipes and outlet pipes connecting the graded sieve tubes; wherein, the multiple graded sieve tubes are connected in series, including a primary sieve tube, a secondary sieve tube and a tertiary sieve tube; the mixing tank is provided with a sample inlet for injecting a mixture of the high-temperature alloy powder to be tested and distilled water; a grid screen is provided at the bottom to prevent backflow of particles, the mesh size of the grid screen is set according to the particle size of the powder to be tested, and it is removable and replaceable; the collection tank is provided with a primary sieve and a secondary sieve for collecting and sieving particles, the mesh size of the sieve is set according to the size of the particles to be separated, and it is a detachable structure for easy replacement and cleaning.

[0013] Furthermore, in the aforementioned device for separating non-metallic inclusions in high-temperature alloy powder by water washing, the volume and size of each stage of the screening tubes are the same, and the diameter of the water discharge tubes of the screening tubes increases progressively from upstream to downstream. Specifically, the diameters of the first-stage, second-stage, and third-stage water discharge tubes increase sequentially, so that when the water pump provides a constant flow rate, the flow velocity of the fluid in each stage of the screening tubes decreases progressively, thereby achieving the separation of non-metallic inclusions of different densities and sizes based on Stokes' sedimentation formula.

[0014] Furthermore, in the aforementioned device for separating non-metallic inclusions in high-temperature alloy powder by water washing, the top of the mixing tank is connected to a primary water inlet pipe, the primary water outlet pipe also serves as a secondary water inlet pipe, the secondary water outlet pipe also serves as a triode water inlet pipe, and the tertiary water outlet pipe is connected to the collection tank by a tertiary sieve pipe.

[0015] Furthermore, the aforementioned device for separating non-metallic inclusions in high-temperature alloy powder by water washing also includes a flow meter installed in the tertiary water outlet pipe for real-time monitoring and adjustment of water flow rate to ensure stable fluid medium velocity within the system. The fluid medium is distilled water or deionized water to avoid reaction with particulate matter and to ensure no impurities interfere with the system. The water pump is an adjustable flow pump, which achieves closed-loop control through flow meter feedback to ensure constant water flow velocity during system operation.

[0016] This invention also utilizes the above-mentioned device to separate high-temperature alloy powder, specifically including the following steps: Step 1: Turn on the device's water pump and adjust it to a suitable fixed flow rate to ensure a stable water flow throughout the system and prevent small air bubbles from remaining in the system pipes. Step 2: Add the metal powder sample solution to be tested, which is mixed with distilled water, into the mixing tank through the sample inlet; Step 3: After the device has been running stably for a period of time, observe that there are no suspended or settled particles in the mixing tank, and then observe the particle movement in each stage tube. Stop the water pump when no more particles flow out of the collection tank. Step 4: Let the residual liquid in each grader tube and collection tank stand. When no suspended particles are observed in the liquid in the tubes and tanks, remove the residual liquid and dry the remaining particles in each grader tube and tank. Step 5: Observe, count, and characterize the sieved particulate matter.

[0017] The advantages and beneficial effects of this utility model are: Based on Stokes' sedimentation formula, a series-connected, progressively increasing diameter sieve tube design achieves a decreasing flow velocity within each sieve tube at a constant system flow rate. This allows for the precise separation of high-temperature alloy powders of the same density but different sizes, and vice versa, from non-metallic inclusions. This overcomes the limitations of traditional water washing devices, which only offer limited screening capabilities. Furthermore, it efficiently removes small, irregularly shaped inclusions, resulting in more thorough separation. Using distilled / deionized water as the medium, along with removable and replaceable grid screens and collection tank screens, it adapts to the separation needs of different specifications of high-temperature alloy powders. The system is easy to operate and environmentally friendly, avoiding the problems of complex parameters in electrostatic separation and the high pollution and poor repeatability of stepwise acid separation. A closed-loop control system using a flow meter and an adjustable water pump ensures stable flow rate, precise and repeatable separation, and low material loss, providing reliable support for subsequent observation, statistics, and characterization of inclusions in high-temperature alloy powders. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the device of this utility model. In the diagram, 100-water pump; 101-system water supply pipe; 102-system lower inlet pipe; 200-mixing tank; 201-grid screen; 202-sampling port; 203-primary pipe inlet pipe; 300-primary sieving pipe; 301-primary pipe dewatering pipe; 400-secondary sieving pipe; 401-secondary pipe dewatering pipe; 500-tertiary sieving pipe; 501-tertiary pipe dewatering pipe; 502-flow meter; 600-collecting tank; 601-primary screen; 602-secondary screen. Detailed Implementation

[0019] The specific embodiments of this utility model will now be described in further detail with reference to the accompanying drawings and examples.

[0020] Example This embodiment discloses an apparatus for separating non-metallic inclusions in high-temperature alloy powder by water washing, comprising a water pump 100, a mixing tank 200, multiple grading sieves and a collection tank 600, and a water pipe system connecting these components; the water pipe system includes a system water supply pipe 101, a system lower water inlet pipe 102, and water inlet pipes and outlet pipes connecting the grading sieves at each level.

[0021] The multiple grading sieve tubes are connected in series, including a primary sieve tube 300, a secondary sieve tube 400, and a tertiary sieve tube 500. Each sieve tube has the same volume and size, and the diameter of the water discharge tube increases progressively from upstream to downstream, specifically the diameters of the primary water discharge tube 301, secondary water discharge tube 401, and tertiary water discharge tube 501. The top of the mixing tank 200 is connected to the primary inlet pipe 203. The primary water discharge tube 301 also serves as the secondary inlet pipe, and the secondary water discharge tube 401 also serves as the triode inlet pipe. A flow meter 502 is installed at the tertiary water discharge tube 501, which is connected to the collection tank 600 via the tertiary sieve tube 500. The mixing tank 200 has a sample inlet 202 and a grid screen 201 at the bottom. The collection tank 600 contains a primary screen 601 and a secondary screen 602, which are detachable.

[0022] A method for separating high-temperature alloy powder using this equipment includes the following steps: Step 1: Calculate and set a reasonable water pump flow rate according to different samples to be tested: Taking the mixed alumina particles in IN718 high-temperature alloy powder as an example, when the minimum size of the particles to be screened is 10 micrometers, the water pump flow rate should be controlled at 12~18L / h. Step 2: Open the system water supply pipe 101, turn on the water pump 100, set the water pump 100 according to the calculated flow rate, and adjust the flow rate of the water pump 100 by measuring the actual flow rate with the flow meter 502. The water flows into the system through the lower water inlet pipe 102, so that the entire system is gradually filled with distilled water. Run stably for half an hour until the fluid inside each screening pipe flows at a uniform speed and there are no small air bubbles. Step 3: Prepare the mixture to be tested, and inject the prepared mixture into the mixing tank 200 through the sampling port 202. During this process, the water pump 100 does not stop, and the fluid medium in the system flows normally. In order to prevent the particles in the mixture from falling back into the water pump, a grid screen 201 is set at the bottom of the mixing tank 200. Step 4: The mixed liquid enters the primary screening pipe 300 through the primary inlet pipe 203. After the screening system has been running stably for ten minutes until there are no obvious particles outside the pipe in the primary screening pipe 300, secondary screening pipe 400 and tertiary screening pipe 500, the 100 water pump is stopped to allow the remaining particles in each screening section of the screening system to settle naturally. Step 5: Sieve and dry the liquid and particulate matter in the sieve tubes and collection tank 600. The primary sieve 601 and the secondary sieve 602 are set according to the size of the particulate matter to be tested and are detachable and replaceable. If the smallest particle size in the sample being sieved is 10 micrometers, the mesh count of the secondary sieve 602 shall not be less than 1400 mesh and the mesh count of the primary sieve 602 shall not be less than 800 mesh.

[0023] Step 6: Observe the particulate matter in each sieve tube and the collection tank after drying, and perform statistical analysis.

Claims

1. A device for separating non-metallic inclusions in high-temperature alloy powder by water washing, characterized in that, The system includes a water pump (100), a mixing tank (200), multiple grading sieves and a collection tank (600), and a water pipe system connecting these components. The water pipe system includes a system water supply pipe (101), a system lower water inlet pipe (102), and inlet and outlet pipes connecting the grading sieves at each level. The multiple grading sieves are connected in series, including a primary sieve (300), a secondary sieve (400), and a tertiary sieve (500). The mixing tank (200) is provided with a sample inlet (202) and a grid screen (201) at the bottom. The collection tank (600) is provided with a primary screen (601) and a secondary screen (602). The aperture of the screen is set according to the size of the particles to be separated and is a detachable structure.

2. The apparatus for separating non-metallic inclusions in high-temperature alloy powder by water washing according to claim 1, characterized in that, The volume and size of each screening tube are the same. The diameter of the water discharge tube of the screening tube increases from upstream to downstream. Specifically, the diameters of the water discharge tubes of the first-stage tube (301), the second-stage tube (401), and the third-stage tube (501) increase in sequence.

3. The apparatus for separating non-metallic inclusions in high-temperature alloy powder by water washing according to claim 1, characterized in that, The top of the mixing tank (200) is connected to the primary tube inlet pipe (203), the primary tube outlet pipe (301) also serves as the secondary tube inlet pipe, the secondary tube outlet pipe (401) also serves as the triode inlet pipe, and the triode outlet pipe (501) is connected to the collection tank (600) by the triode sieve pipe (500).

4. The apparatus for separating non-metallic inclusions in high-temperature alloy powder by water washing according to claim 1, characterized in that, It also includes a flow meter (502), which is installed in the tertiary pipe off-pipe (501).

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