A method of integrally forming a process for a reactive metal melt impeller

Abstract

The application relates to a one-piece processing method of a reactive metal melt stirring paddle, which comprises the following steps: constructing a basic three-dimensional model of a refractory metal stirring paddle; adding a bottom support structure to obtain a forming three-dimensional model, wherein the bottom support structure comprises a mutually nested entity support structure and a grid support structure; carrying out slice processing on the forming three-dimensional model to obtain slice data, and carrying out scanning path planning on the slice data to obtain scanning path data; adopting a laser beam to selectively melt and scan print refractory metal powder, and processing and forming a metal stirring paddle rough product through layer-by-layer stacking; and carrying out post-processing and sand blasting treatment to obtain a reactive metal melt stirring paddle finished product. Compared with the prior art, the application selectively melts metal powder according to a workpiece model, and a three-dimensional entity part is manufactured in a way of layer-by-layer powder laying and layer-by-layer melting and solidification accumulation, the impeller and the stirring shaft can be integrally formed, the whole part has good high-temperature corrosion resistance, and the service life is prolonged.

Description

Technical Field

[0001] This invention relates to the field of nuclear metallurgy, and in particular to a method for integral forming of a stirring paddle for molten active metal. Background Technology

[0002] In the field of nuclear metallurgy, the agitator materials used in the smelting of reactive metals and alloys are made of refractory metals such as tantalum (Ta), tungsten, or molybdenum, due to their excellent high-temperature strength and good corrosion resistance to reactive metals, molten alkali metals, and vapors. The agitator consists of an impeller and an agitator shaft, and the connection between the impeller and the agitator shaft should be reliable and stable. Currently, for simplicity, small impellers are often welded to a hub to form a single unit, and then the hub is connected to the agitator shaft using keys and locking screws, or the impeller is directly welded to the agitator shaft. Under high-temperature conditions and during long-term contact with molten metal, the welded joints of the agitator are prone to severe corrosion, contaminating the molten metal. Therefore, if a high-temperature corrosion-resistant material could be integrally molded into an agitator, corrosion failure at the welded joints could be avoided, preventing contamination of the molten metal.

[0003] Chinese invention patent CN201610877949.9 describes a stirring paddle structure for stirring metal powders where the blades are fixed to or welded to a rotating shaft using screws. Powder tends to accumulate at the screw fixing points, and the welded points experience prolonged friction and heating with the powder during stirring, affecting performance. Chinese patent CN202020738844.7 designs an aluminum alloy melt stirring paddle with blades welded to a stirring shaft. Chinese patent CN201520143662.4 designs a stirring paddle suitable for iron powder reduction, where the blades are clamped to or welded to a rotating shaft. Since this patent targets reactive metal melts, the stirring paddle material must possess good corrosion resistance at temperatures above 600℃. Refractory metals such as tantalum, tungsten, and molybdenum show significant advantages, but due to their poor machinability, it is necessary to research methods for integral molding to obtain a fully corrosion-resistant high-temperature component and extend its service life. Summary of the Invention

[0004] This invention addresses the problem that the welded joints of agitators are prone to severe corrosion during long-term contact with molten metal at high temperatures, causing contamination of the molten metal solution. It provides a processing method for integrally forming a high-temperature corrosion-resistant metal material. This invention utilizes laser selective melting to selectively melt metal powder according to the workpiece model. Through layer-by-layer powder spreading and melting / solidification, a three-dimensional solid part is manufactured. This method allows for the integral forming of the impeller and agitator shaft, achieving excellent high-temperature corrosion resistance and extending the service life of the entire part.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] This invention provides a method for integrally forming a stirring paddle for molten active metal, comprising the following steps:

[0007] S1: Construct the basic three-dimensional model of the refractory metal stirring paddle;

[0008] S2: Based on the basic three-dimensional model, a bottom support structure is added to it to obtain a shaped three-dimensional model. The bottom support structure includes nested solid support structures and mesh support structures.

[0009] S3: Slice the formed three-dimensional model to obtain slice data, and perform scan path planning on the slice data to obtain scan path data;

[0010] S4: Based on the scanning path data, a laser beam is used to perform selective melting scanning printing on refractory metal powder, and the powder is processed by stacking layers to obtain a rough metal stirring paddle.

[0011] S5: The obtained crude metal agitator is post-processed by sandblasting to obtain the finished active metal melt agitator.

[0012] Furthermore, in S1, a basic three-dimensional model of a refractory metal stirring impeller is constructed using Solidworks software. The modeling dimensions are as follows: stirring impeller height 50-100mm, stirring impeller height to blade diameter ratio 4-6, circumferential speed 20-30cm / s, and blades with opposite turns of 35°-45°.

[0013] Furthermore, in S2, Materialise Magics software is used to add a support structure to the bottom of the basic three-dimensional model of the refractory metal stirring paddle.

[0014] Furthermore, in S3, the Build Planner software is used to slice the formed 3D model to obtain slice data, and scan path planning is performed on the slice data to form scan path data.

[0015] Furthermore, in S4, the refractory metal powder used is selected from one or more of tantalum powder, tungsten powder, and molybdenum powder.

[0016] Furthermore, in S4, the refractory metal powder is prepared by a plasma rotating electrode atomization process, with a powder particle size of 10-53 μm and an oxygen content of less than 200 ppm.

[0017] Furthermore, in S4, before selective melting scanning printing, argon gas with a purity of 99.999% is introduced into the forming chamber at a flow rate of 4-5 L / min, and the oxygen concentration in the forming chamber is controlled to be no higher than 10 ppm.

[0018] Furthermore, in S4, the selected area melting scan printing process specifically includes:

[0019] The refractory metal powder is loaded into the forming chamber of the laser selective melting equipment;

[0020] Refractory metal powder is evenly spread on the titanium alloy substrate of the forming chamber;

[0021] Based on the imported scanning path data, a laser beam is used to perform selective melting scanning printing on refractory metal powder;

[0022] The parameters for the melting scan printing include:

[0023] The powder thickness is 20-60μm, the scanning method is strip mode, the scanning interval is 0.04-0.11mm, the spot diameter is 100μm, the laser power is 150-250W, and the scanning rate is 200-800mm / s.

[0024] Further, in S4, the post-processing includes: placing the crude molybdenum agitator into a vacuum heat treatment furnace and holding it at 1350°C for 120 minutes with a vacuum degree of 5×10⁻⁶. -3 Pa, through heat treatment to eliminate internal residual stress and prevent cracking and deformation, the heat-treated molybdenum agitator is then cut off from the substrate.

[0025] Further, in S5, the process parameters for the sandblasting treatment include: the sandblasting particles are Al2O3 with a diameter of 0.3-0.85 mm, the sandblasting speed is 0.8-1 m / min, the air pressure is 0.2-0.4 MPa, and the sandblasting time is 0.01-0.03 m. 2 / min.

[0026] Compared with the prior art, the present invention has the following technical advantages:

[0027] (1) The present invention adopts an integral molding processing method, which uses 3D printing technology to stack metal stirring paddles layer by layer to form the shape. Compared with traditional processing methods, it can reduce material waste and processing steps and improve production efficiency. By using laser selective melting method, the stirring paddle does not require molds in the entire manufacturing process, which reduces manufacturing steps, shortens the manufacturing cycle of parts, and reduces costs.

[0028] (2) The present invention adds a bottom support structure to the basic three-dimensional model of the stirring paddle, including a solid support structure and a grid support structure, which can provide stable support and fixation, and ensure the shape and structural integrity of the stirring paddle during the printing process.

[0029] (3) The present invention uses spherical powder forming and layer-by-layer stacking to obtain a dense microstructure of refractory metal stirring paddle. Since the stirring paddle is formed in one piece, the entire part can have good high temperature corrosion resistance and extend service life.

[0030] (4) This invention uses refractory metal powder for selective melting scanning printing, which improves the high temperature resistance and corrosion resistance of the stirring paddle. The refractory metal powder is prepared by plasma rotating electrode atomization process, which has a small particle size and low oxygen content, thus improving the printing quality and material properties.

[0031] (5) The present invention performs post-processing on the rough agitator obtained by printing, including vacuum heat treatment and sandblasting. Vacuum heat treatment can eliminate internal residual stress, prevent cracking and deformation, and improve the strength and stability of the agitator. Sandblasting can improve the surface smoothness and roughness of the agitator, and improve its service life and performance. Attached Figure Description

[0032] Figure 1 This is a flowchart of the metal stirring paddle preparation method in this invention;

[0033] Figure 2 This is a model diagram of the preparation of the stirring paddle using laser selective melting in this invention;

[0034] Figure 3 This is a physical image of the stirring paddle prepared by selective laser melting in this invention;

[0035] Figure 4 This is a microstructure diagram of the stirring impeller prepared by selective laser melting in this invention. Detailed Implementation

[0036] The invention uses high-purity tantalum, high-purity tungsten, and high-purity molybdenum metal powders as raw materials and employs a laser selective melting device with a stirring paddle. The process flow of this invention is as follows (e.g.) Figure 1 The process (as shown) involves: constructing a 3D model → constructing a support structure → slicing → data import → powder preparation → argon purging → powder spreading → selective laser melting → heat treatment → wire cutting → surface treatment (sandblasting). Specifically, it includes the following steps:

[0037] (1) A three-dimensional model of the impeller to be machined was created using Solidworks software. The model dimensions were: impeller height 50-100mm, height-to-blade diameter ratio 4-6, circumferential speed 20-30cm / s, and blades with opposite turns of 35°-45°. The model diagram is shown below. Figure 2 As shown;

[0038] (2) To prevent the agitator from cracking, a support structure is added to the bottom of the three-dimensional model of the refractory metal agitator constructed in step (1) using Materialise Magics software. The support structure includes solid support and mesh support, which are nested together.

[0039] (3) Use Build Planner software to slice the three-dimensional model and support structure constructed in steps (1) and (2) to obtain slice data, and perform scan path planning on the slice data to form scan path data;

[0040] (4) Import the scan path data planned in step (3) into the laser selective melting equipment;

[0041] (5) Load 12 kg of spherical refractory metal powder into the laser selective melting equipment;

[0042] (6) Inert gas argon (purity 99.999%) is introduced into the forming chamber at a flow rate of 4-5 L / min, and the oxygen concentration in the forming chamber is controlled to be no higher than 10 ppm.

[0043] (7) Spread spherical refractory metal powder with an area of ​​105mm×105mm evenly on the titanium alloy substrate of the forming chamber.

[0044] (8) Based on the scanning path data imported in step (4), a laser beam is used to perform selective melting scanning printing on refractory metal powder. The printing process is carried out in the order of support, lower surface, main body and upper surface. The scanning mode, laser power, scanning rate and scanning spacing process parameters are adjusted. The powder thickness is 20-60μm, the scanning mode is strip mode, the scanning spacing is 0.04-0.11mm, the spot diameter is 100μm, the laser power is 150-250W, and the scanning rate is 200-800mm / s. The metal stirring paddle is formed by stacking layers.

[0045] (9) Place the metal stirring paddle obtained in step (8) into a vacuum heat treatment furnace and hold it at 900-1500℃ for 60-150 min with a vacuum degree of 2×10⁻⁶. -3 -6×10 -3 Pa, through heat treatment to eliminate its internal residual stress and prevent cracking and deformation;

[0046] (10) Cut the heat-treated metal agitator from the substrate in step (9).

[0047] (11) The agitator printed in step (10) is subjected to sandblasting. The sandblasting process conditions are as follows: the sand particles are Al2O3 with a diameter of 0.3-0.85 mm, the sandblasting speed is 0.8-1 m / min, the air pressure is 0.2-0.4 MPa, and the sandblasting time is 0.01-0.03 m.2 / min, to obtain a metal agitator that ultimately meets the requirements of industrial applications.

[0048] This process allows for the rapid heating and cooling of spherical refractory metal powder by adjusting the scanning method, laser power, scanning rate, and scanning spacing, and then stacking the powder layer by layer to form a three-dimensional solid.

[0049] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Any structural / module names, control modes, algorithms, processes, or composition ratios not explicitly described in this technical solution are considered common technical features disclosed in the prior art.

[0050] Example 1

[0051] Raw materials and requirements: High-purity tantalum metal powder (tantalum content greater than 99.95 wt.%)

[0052] (1) Use Solidworks software to construct a three-dimensional model of the tantalum stirring impeller to be processed. The model size is 100mm in height, the ratio of blade diameter to height is 4, the circumferential speed is 20cm / s, and the blades are turned in opposite directions at 45°.

[0053] (2) To prevent cracking at the connection between the impeller and the substrate, a support structure was added to the bottom of the 3D model of the tantalum impeller constructed in step (1) using Materialise Magics software. This support structure includes solid supports and mesh supports, which are nested together. See [link to relevant documentation]. Figure 2 ;

[0054] (3) Use Build Planner software to transform the 3D model into a printable model that can contain printing information, slice and layer it to obtain slice data, and perform scan path planning on the slice data to form scan path data.

[0055] (4) Import the scan path data planned in step (3) into the laser selective melting equipment;

[0056] (5) Load 12 kg of spherical tantalum powder into the forming chamber of the laser selective melting equipment;

[0057] (6) Inert gas high-purity argon (purity 99.99%) is introduced into the forming chamber. The argon flow rate is 4-5 L / min, and the oxygen concentration in the forming chamber is controlled to be no higher than 10 ppm.

[0058] (7) Spread spherical tantalum powder with an area of ​​105mm×105mm evenly on the titanium alloy substrate of the forming chamber.

[0059] (8) Based on the scanning path data imported in step (4), a laser beam is used to perform selective melting scanning printing on refractory metal powder. The printing process is carried out in the order of support, lower surface, main body and upper surface. The scanning mode, laser power, scanning rate and scanning spacing process parameters are adjusted. The powder thickness is 20μm, the scanning mode is strip mode, the scanning spacing is 0.04mm, the spot diameter is 100μm, the laser power is 200W and the scanning rate is 300mm / s. The tantalum stirring paddle is obtained by stacking layers.

[0060] (9) Place the metal stirring paddle obtained in step (8) into a vacuum heat treatment furnace and hold it at 900℃ for 60 min with a vacuum degree of 5×10⁻⁶. -3 Pa, through heat treatment to eliminate its internal residual stress and prevent cracking and deformation;

[0061] (10) Cut the heat-treated metal agitator from the substrate in step (9).

[0062] (11) The agitator printed in step (10) is subjected to sandblasting. The sandblasting process conditions are as follows: the sand particles are Al2O3 with a diameter of 0.3-0.85 mm, the sandblasting speed is 0.8-1 m / min, the air pressure is 0.2-0.4 MPa, and the sandblasting time is 0.01-0.03 m. 2 / min, to obtain the final metal agitator that meets industrial application requirements, see [link / min]. Figure 3 .

[0063] For the microstructure of the stirred impeller prepared by selective laser melting, see [link to documentation]. Figure 4 ,Depend on Figure 4 It is evident that the microstructure of tantalum exhibits typical equiaxed crystal characteristics, with good uniformity in grain size (average of approximately 50 micrometers), and the absence of pores and inclusions, indicating that the laser selective melting process produces high-quality results.

[0064] Example 2

[0065] Raw materials and requirements: High-purity tantalum metal powder (tantalum content greater than 99.95 wt.%)

[0066] (1) Use Solidworks software to construct a three-dimensional model of the tantalum stirring impeller to be processed. The model size is 100mm in height, the ratio of blade diameter to height is 5, the circumferential speed is 25cm / s, and the blades are turned in opposite directions at 45°.

[0067] (2) To prevent cracking at the connection between the stirring paddle and the substrate, a support structure is added to the bottom of the three-dimensional model of the tantalum stirring paddle constructed in step (1) using Materialise Magics software. The support structure includes solid support and mesh support, which are nested together.

[0068] (3) Use Build Planner software to transform the 3D model into a printable model that can contain printing information, slice and layer it to obtain slice data, and perform scan path planning on the slice data to form scan path data.

[0069] (4) Import the scan path data planned in step (3) into the laser selective melting equipment;

[0070] (5) Load 12 kg of spherical tantalum powder into the forming chamber of the laser selective melting equipment;

[0071] (6) Inert gas high-purity argon (purity 99.99%) is introduced into the forming chamber. The argon flow rate is 4-5 L / min, and the oxygen concentration in the forming chamber is controlled to be no higher than 10 ppm.

[0072] (7) Spread spherical tantalum powder with an area of ​​105mm×105mm evenly on the titanium alloy substrate of the forming chamber.

[0073] (8) Based on the scanning path data imported in step (4), a laser beam is used to perform selective melting scanning printing on refractory metal powder. The printing process is carried out in the order of support, lower surface, main body and upper surface. The scanning mode, laser power, scanning rate and scanning spacing process parameters are adjusted. The powder thickness is 30μm, the scanning mode is strip mode, the scanning spacing is 0.04mm, the spot diameter is 100μm, the laser power is 200W and the scanning rate is 300mm / s. The tantalum stirring paddle is obtained by stacking layers.

[0074] (9) Place the metal stirring paddle obtained in step (8) into a vacuum heat treatment furnace and hold it at 900℃ for 120 min with a vacuum degree of 5×10⁻⁶. -3 Pa, through heat treatment to eliminate its internal residual stress and prevent cracking and deformation;

[0075] (10) Cut the heat-treated metal agitator from the substrate in step (9);

[0076] (11) The agitator printed in step (10) is subjected to sandblasting. The sandblasting process conditions are as follows: the sand particles are Al2O3 with a diameter of 0.3-0.85 mm, the sandblasting speed is 0.8-1 m / min, the air pressure is 0.2-0.4 MPa, and the sandblasting time is 0.01-0.03 m. 2 / min, to obtain a metal agitator that ultimately meets the requirements of industrial applications.

[0077] Example 3

[0078] Raw materials and requirements: High-purity tantalum metal powder (tantalum content greater than 99.95 wt.%)

[0079] (1) Use Solidworks software to construct a three-dimensional model of the tantalum stirring impeller to be processed. The model size is 100mm in height, the ratio of blade diameter to height is 6, the circumferential speed is 30cm / s, and the blades are turned in opposite directions at 45°.

[0080] (2) To prevent cracking at the connection between the stirring paddle and the substrate, a support structure is added to the bottom of the three-dimensional model of the tantalum stirring paddle constructed in step (1) using Materialise Magics software. The support structure includes solid support and mesh support, which are nested together.

[0081] (3) Use Build Planner software to transform the 3D model into a printable model that can contain printing information, slice and layer it to obtain slice data, and perform scan path planning on the slice data to form scan path data.

[0082] (4) Import the scan path data planned in step (3) into the laser selective melting equipment;

[0083] (5) Load 12 kg of spherical tantalum powder into the forming chamber of the laser selective melting equipment;

[0084] (6) Inert gas high-purity argon (purity 99.99%) is introduced into the forming chamber. The argon flow rate is 4-5 L / min, and the oxygen concentration in the forming chamber is controlled to be no higher than 10 ppm.

[0085] (7) Spread spherical tantalum powder with an area of ​​105mm×105mm evenly on the titanium alloy substrate of the forming chamber.

[0086] (8) Based on the scanning path data imported in step (4), a laser beam is used to perform selective melting scanning printing on refractory metal powder. The printing process is carried out in the order of support, lower surface, main body and upper surface. The scanning mode, laser power, scanning rate and scanning spacing process parameters are adjusted. The powder thickness is 30μm, the scanning mode is strip mode, the scanning spacing is 0.04mm, the spot diameter is 100μm, the laser power is 220W and the scanning rate is 300mm / s. The tantalum stirring paddle is obtained by stacking layers.

[0087] (9) Place the tantalum stirring paddle obtained in step (8) into a vacuum heat treatment furnace and hold it at 900℃ for 120 min with a vacuum degree of 5×10⁻⁶. -3 Pa, through heat treatment to eliminate its internal residual stress and prevent cracking and deformation;

[0088] (10) Cut the tantalum stirring paddle after heat treatment in step (9) off the substrate.

[0089] (11) The agitator printed in step (10) is subjected to sandblasting. The sandblasting process conditions are as follows: the sand particles are Al2O3 with a diameter of 0.3-0.85 mm, the sandblasting speed is 0.8-1 m / min, the air pressure is 0.2-0.4 MPa, and the sandblasting time is 0.01-0.03 m. 2 / min, to obtain a tantalum metal agitator that ultimately meets the requirements of industrial applications.

[0090] Example 4

[0091] Raw materials and requirements: High-purity tungsten (tungsten content greater than 99.95 wt.%)

[0092] (1) Use Solidworks software to construct a three-dimensional model of the tungsten stirring impeller to be processed. The model size is 100mm in height, the ratio of blade diameter to height is 6, the circumferential speed is 30cm / s, and the blades are turned in opposite directions at 45°.

[0093] (2) To prevent cracking at the connection between the impeller and the substrate, a support structure is added to the bottom of the three-dimensional model of the tungsten impeller constructed in step (1) using Materialise Magics software. The support structure includes solid support and mesh support, which are nested together.

[0094] (3) Use Build Planner software to transform the 3D model into a printable model that can contain printing information, slice and layer it to obtain slice data, and perform scan path planning on the slice data to form scan path data.

[0095] (4) Import the scan path data planned in step (3) into the laser selective melting equipment;

[0096] (5) Load 12 kg of spherical tungsten powder into the forming chamber of the laser selective melting equipment;

[0097] (6) Inert gas high-purity argon (purity 99.99%) is introduced into the forming chamber. The argon flow rate is 4-5 L / min, and the oxygen concentration in the forming chamber is controlled to be no higher than 10 ppm.

[0098] (7) Spread spherical tungsten powder with an area of ​​105mm×105mm evenly on the titanium alloy substrate of the forming chamber.

[0099] (8) Based on the scanning path data imported in step (4), a laser beam is used to perform selective melting scanning printing on refractory metal powder. The printing process is carried out in the order of support, lower surface, main body and upper surface. The scanning mode, laser power, scanning rate and scanning spacing process parameters are adjusted. The powder thickness is 30μm, the scanning mode is strip mode, the scanning spacing is 0.05mm, the spot diameter is 100μm, the laser power is 180W and the scanning rate is 500mm / s. The metal tungsten stirring paddle is obtained by stacking layers.

[0100] (9) Place the tungsten stirring paddle obtained in step (8) into a vacuum heat treatment furnace and hold it at 1500℃ for 120 min with a vacuum degree of 5×10⁻⁶. -3 Pa, through heat treatment to eliminate its internal residual stress and prevent cracking and deformation;

[0101] (10) Cut the tungsten stirring paddle after heat treatment in step (9) off the substrate;

[0102] (11) The agitator printed in step (10) is subjected to sandblasting. The sandblasting process conditions are as follows: the sand particles are Al2O3 with a diameter of 0.3-0.85 mm, the sandblasting speed is 0.8-1 m / min, the air pressure is 0.2-0.4 MPa, and the sandblasting time is 0.01-0.03 m. 2 / min, to obtain a tungsten metal agitator that ultimately meets the requirements of industrial applications.

[0103] Example 5

[0104] Raw materials and requirements: High-purity molybdenum (molybdenum content greater than 99.95 wt.%)

[0105] (1) Use Solidworks software to construct a three-dimensional model of the molybdenum stirring impeller to be processed. The model size is 100mm in height, the ratio of blade diameter to height is 6, the circumferential speed is 30cm / s, and the blades are turned in opposite directions at 45°.

[0106] (2) To prevent cracking at the connection between the agitator and the substrate, a support structure is added to the bottom of the three-dimensional model of the molybdenum agitator constructed in step (1) using Materialise Magics software. The support structure includes solid support and mesh support, which are nested together.

[0107] (3) Use Build Planner software to transform the 3D model into a printable model that can contain printing information, slice and layer it to obtain slice data, and perform scan path planning on the slice data to form scan path data.

[0108] (4) Import the scan path data planned in step (3) into the laser selective melting equipment;

[0109] (5) Load 12 kg of spherical molybdenum powder into the forming chamber of the laser selective melting equipment;

[0110] (6) Inert gas high-purity argon (purity 99.99%) is introduced into the forming chamber. The argon flow rate is 4-5 L / min, and the oxygen concentration in the forming chamber is controlled to be no higher than 10 ppm.

[0111] (7) Spread spherical molybdenum powder with an area of ​​105mm×105mm evenly on the titanium alloy substrate of the forming chamber.

[0112] (8) Based on the scanning path data imported in step (4), a laser beam is used to perform selective melting scanning printing on refractory metal powder. The printing process is carried out in the order of support, lower surface, main body and upper surface. The scanning mode, laser power, scanning rate and scanning spacing process parameters are adjusted. The powder thickness is 30μm, the scanning mode is strip mode, the scanning spacing is 0.05mm, the spot diameter is 100μm, the laser power is 200W and the scanning rate is 400mm / s. The molybdenum stirring paddle is obtained by stacking layers.

[0113] (9) Place the molybdenum stirring paddle obtained in step (8) into a vacuum heat treatment furnace and hold it at 1350℃ for 120 min with a vacuum degree of 5×10⁻⁶. -3 Pa, through heat treatment to eliminate its internal residual stress and prevent cracking and deformation;

[0114] (10) Cut the heat-treated molybdenum stirring paddle from the substrate after step (9).

[0115] (11) The printed molybdenum agitator from step (10) is subjected to sandblasting. The sandblasting process conditions are as follows: the sand particles are Al2O3 with a diameter of 0.3-0.85 mm, the sandblasting speed is 0.8-1 m / min, the air pressure is 0.2-0.4 MPa, and the sandblasting time is 0.01-0.03 m. 2 / min, to obtain a molybdenum metal agitator that ultimately meets the requirements of industrial applications.

[0116] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for integrally forming a stirring paddle for molten active metal, characterized in that, Includes the following steps: S1: Construct the basic three-dimensional model of the refractory metal stirring paddle; S2: Based on the basic three-dimensional model, a bottom support structure is added to it to obtain a shaped three-dimensional model. The bottom support structure includes nested solid support structures and mesh support structures. S3: Slice the formed three-dimensional model to obtain slice data, and perform scan path planning on the slice data to obtain scan path data; S4: Based on the scanning path data, a laser beam is used to selectively melt and scan the refractory metal powder, and the powder is then stacked layer by layer to form a rough metal stirring paddle. S5: The obtained rough metal agitator is post-processed by sandblasting to obtain the finished active metal melt agitator. In S1, a basic three-dimensional model of a refractory metal stirring impeller is constructed using Solidworks software. The modeling dimensions are as follows: stirring impeller height 50-100 mm, stirring impeller height to blade diameter ratio 4-6, circumferential speed 20-30 cm / s, and blades with opposite turns of 35°-45°. In S2, Materialise Magics software was used to add a support structure to the bottom of the basic three-dimensional model of the refractory metal stirring paddle; In S3, the Build Planner software is used to slice the formed 3D model to obtain slice data, and scan path planning is performed on the slice data to form scan path data.

2. The integral forming method for a stirring paddle for molten active metal according to claim 1, characterized in that, In S4, the refractory metal powder used is selected from one or more of tantalum powder, tungsten powder, and molybdenum powder.

3. The integral forming method for a stirring impeller for molten active metal according to claim 2, characterized in that, In S4, the refractory metal powder is prepared by plasma rotating electrode atomization process, with a powder particle size of 10-53 μm and an oxygen content of less than 200 ppm.

4. The integral forming method for a stirring paddle for molten active metal according to claim 2, characterized in that, In S4, before selective melting scanning printing, argon gas with a purity of 99.999% is introduced into the forming chamber at a flow rate of 4-5 L / min, and the oxygen concentration in the forming chamber is controlled to be no higher than 10 ppm.

5. The integral forming method for a stirring impeller for molten active metal according to claim 1, characterized in that, In S4, the selected area melting scan printing process specifically includes: The refractory metal powder is loaded into the forming chamber of the laser selective melting equipment; Refractory metal powder is evenly spread on the titanium alloy substrate of the forming chamber; Based on the imported scanning path data, a laser beam is used to perform selective melting scanning printing on refractory metal powder; The parameters for the melting scan printing include: The powder thickness is 20-60 μm, the scanning method is strip mode, the scanning interval is 0.04-0.11 mm, the spot diameter is 100 μm, the laser power is 150-250 W, and the scanning rate is 200-800 mm / s.

6. The integral forming method for a stirring paddle for molten active metal according to claim 1, characterized in that, In S5, the post-processing includes: placing the crude molybdenum agitator into a vacuum heat treatment furnace and holding it at 1350 °C for 120 min under a vacuum of 5 × 10⁻⁶. -3 Pa, through heat treatment to eliminate internal residual stress and prevent cracking and deformation, and then the heat-treated molybdenum agitator is cut off from the substrate.

7. The integral forming method for a stirring paddle for molten active metal according to claim 1, characterized in that, In S5, the process parameters for the sandblasting treatment include: the sandblasting particles are Al2O3 with a diameter of 0.3-0.85 mm, and the air pressure is 0.2-0.4 MPa.

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