Pressurized package powder filling device for hot isostatic pressing and powder filling method

Abstract

The invention belongs to the technical field of powder metallurgy, and relates to a supercharged package powder filling device for hot isostatic pressing and a powder filling method. The powder filling method comprises the following steps: firstly, vacuumizing the sheath and the powder tank by using a vacuum pump, and carrying out argon replacement on the interiors of the sheath and the powder tank by using argon; the powder tank is independently filled with inert gas, and the sheath is independently vacuumized, so that a certain pressure difference exists between the powder tank and the sheath, and powder filling in the later period is facilitated; then, according to a cavity model in the computer modeling sheath, setting a motion path of a powder feeding shaft; then, the powder is filled into the sheath through the powder feeding shaft under the action of the pressure difference; and finally, the sheath gradually descends through the lifting platform until the inner cavity of the sheath is fully filled. According to the powder filling method, the powder in the sheath is compactly filled and is not limited by the shape of the sheath, and the phenomena that the welding seam of the sheath is influenced by long-time vibration of the large-size sheath and the particle size distribution of the powder at different positions is not uniform are effectively avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of powder metallurgy, and relates to a pressurized bag powder filling device and a powder filling method for hot isostatic pressing. Background Art

[0002] Powder metallurgy hot isostatic pressing technology is a technology that uses argon as a medium to consolidate powders under the action of high temperature and high pressure. Compared with powder metallurgy sintering technology, powder metallurgy hot isostatic pressing technology can obtain higher density. Compared with 3D printing technology, the mechanical properties of the processed parts by powder metallurgy hot isostatic pressing are uniform in all directions without obvious anisotropy.

[0003] The implementation method of powder metallurgy hot isostatic pressing technology is as follows: First, the shape and size of the final finished part are inversely deduced to design a suitable-shaped and sized bag, then the powder is filled into the bag and the excess gas in the bag is removed, and then hot isostatic pressing is carried out. As the front-end process of powder metallurgy hot isostatic pressing, powder filling is crucial for the shape and performance of the final parts after hot isostatic pressing. To ensure the normal production of the parts after hot isostatic pressing: First, it is necessary to ensure that the bag is filled densely during powder filling in the early stage. If the powder is not filled densely, it will cause serious shrinkage of the parts after hot isostatic pressing and the size and shape of the final parts cannot be processed. Seriously, it may cause the bag weld to crack due to excessive deformation. Moreover, it is necessary to ensure that the powder particle size is uniform at each position in the bag, otherwise the shrinkage of each position of the parts after hot isostatic pressing will be uneven, resulting in the inability to process the shape of the finished parts that meet the requirements.

[0004] Currently, for powder filling before hot isostatic pressing, the welded bag is often fixed on a vibrating platform through a tooling fixture. During the powder feeding process, the vibration of the platform driven by the motor drives the bag to vibrate together, so as to achieve dense filling of the powder in the bag. However, during the powder filling process, continuous vibration will cause the bag weld to bear alternating stress for a long time, which is extremely likely to cause the weld to crack and lead to bag air leakage. In addition, for complex-shaped powder filling bags, the complexity of their structure will inevitably make it difficult to fix the bag on the vibrating platform, and it is difficult to achieve dense filling of the powder at the corner positions of the special-shaped bag by vibrating powder filling.

[0005] In view of this, the present invention is specifically proposed. Summary of the Invention

[0006] The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art, and provide a pressurized bag powder filling device and a powder filling method for hot isostatic pressing, which reduce the risk of powder oxidation during the powder filling process through argon replacement, and use a multi-degree-of-freedom powder feeding shaft and a lifting platform to ensure that the powder in each corner of the bag can be filled without continuous vibration.

[0007] To achieve the above purpose, the present invention provides the following technical solutions:

[0008] The pressurized powder-packing device for hot isostatic pressing provided by the present invention includes a lifting platform, on which a powder bag is fixed, and metal powder is contained in the powder bag; a powder feeding shaft with multi-degree-of-freedom movement is arranged at the top of the powder bag, and the powder feeding shaft is communicated with a powder tank located above it; a vacuum extraction port and an inert gas replacement port are respectively arranged at the top of the powder tank, the vacuum extraction port is connected with a vacuum pump through a vacuum pipeline, the inert gas replacement port is connected with an inert gas replacement device through an inert gas replacement pipeline, and both the vacuum pipeline and the inert gas replacement pipeline are communicated with the powder feeding shaft.

[0009] Specifically, the lifting platform includes a platform located above and telescopic supports located below the platform, and the telescopic supports realize the lifting of the platform under the drive of a cylinder.

[0010] Specifically, the powder feeding shaft with multi-degree-of-freedom movement includes an outer layer and an inner layer: the outer layer is a stainless steel multi-joint flexible shaft, and the movement track of the stainless steel multi-joint flexible shaft is controlled by a PLC controller; the inner layer is integrated with a wear-resistant plastic hose for the directional transportation of metal powder.

[0011] Specifically, the vacuum pipeline includes a first pipeline connected with a vacuum pump, the first pipeline is communicated with the powder feeding shaft through a first valve, a first branch pipeline is arranged on the first pipeline, and the first branch pipeline is communicated with the vacuum extraction port through a second valve. In addition, a vacuum gauge for monitoring the vacuum degree is also arranged on the first pipeline.

[0012] Specifically, the inert gas replacement pipeline includes a second pipeline connected with an inert gas replacement device, the second pipeline is communicated with the powder feeding shaft through a third valve, a second branch pipeline is arranged on the second pipeline, and the second branch pipeline is communicated with the inert gas replacement port through a fourth valve.

[0013] Specifically, the inert gas replacement device includes a supercharger, the supercharger is connected with an inert gas station through a third pipeline, and the supercharger is connected with the powder feeding shaft through the second pipeline and a third valve.

[0014] Specifically, a powder outlet is arranged at the bottom of the powder tank, the powder outlet is communicated with the powder feeding shaft through a fourth pipeline, and a fifth valve is arranged on the fourth pipeline.

[0015] Specifically, a pressure gauge is arranged at the top of the powder tank.

[0016] In addition, the present invention also provides a powder-packing method for the pressurized powder-packing device for hot isostatic pressing as described in part or all of the above, which specifically includes the following steps:

[0017] Step 1: Fix and install the powder bag on the lifting platform;

[0018] Step 2. Evacuate the shroud and the powder tank: Close the inert gas replacement pipeline, open the vacuum pipeline, and use a vacuum pump to evacuate the inside of the shroud and the powder tank until the vacuum degree meets the requirements, then close the vacuum pipeline.

[0019] Step 3. Fill the shroud and the powder tank with inert gas: Open the inert gas replacement pipeline, and use an inert gas replacement device to inject inert gas into the inside of the shroud and the powder tank through the inert gas replacement pipeline.

[0020] Step 4. Repeat Step 2 and Step 3 multiple times to reduce the oxygen content in the powder tank and the shroud by multiple evacuations and inert gas fillings, and then fill the powder tank with inert gas alone: Keep the vacuum pipeline closed, and use an inert gas replacement device to inject inert gas into the powder tank only through the inert gas replacement pipeline until the pressure in the powder tank is in the range of 0.10 - 0.15 MPa.

[0021] Step 5. Evacuate the shroud alone: Close the inert gas replacement pipeline, and use a vacuum pump to evacuate the inside of the shroud alone until the vacuum degree < 1.0×10 -3 Pa, then stop evacuating.

[0022] Step 6. Perform three-dimensional modeling and three-dimensional slicing on the cavity structure inside the shroud.

[0023] Step 7. Set the movement path of each slice layer of the powder feeding shaft according to the shape of each slice in the three-dimensional modeling.

[0024] Step 8. Start the rotating blade in the powder tank and set the rotation speed at 45 - 55 r / min.

[0025] Step 9. Open the fifth valve, use the pressure difference to load the powder into the shroud, and at the same time, the powder feeding shaft moves according to the set movement path of each slice layer.

[0026] Step 10. After filling one layer of powder, close the powder outlet, the lifting platform drives the shroud to descend a specified distance, then open the powder outlet to fill the next layer of powder until the inside of the entire shroud is filled with powder.

[0027] Among them, the inert gas is argon, and the purity of the argon ≥ 99.999%, and the gas impurity content meets the following requirements: H2 < 0.5 ppm, O2 < 1.5 ppm, H2O < 3 ppm.

[0028] Further, in step 9, during the entire powder charging process under pressure, if the pressure in the powder tank is < 0.10 MPa, first close the fifth valve, and at the same time open the corresponding valve in the vacuum pipeline. Use a vacuum pump to evacuate the inside of the jacket until the vacuum degree inside the jacket is < 5 Pa, then close the corresponding valve in the vacuum pipeline and stop evacuating. Then, replenish inert gas into the powder tank to keep the pressure in the powder tank at 0.10 - 0.15 MPa, and then open the powder feeding port to continue powder charging.

[0029] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0030] 1) Before powder charging, the present invention evacuates the powder tank and the jacket (step 2) and fills them with inert gas (step 3) and conducts multiple replacements, which can reduce the risk of powder oxidation during powder charging and ensure the product quality of the final product. At the same time, through the operations in steps 4 and 5, a certain pressure difference is created between the powder tank and the jacket, facilitating subsequent powder charging.

[0031] 2) The rotating blades provided inside the powder tank keep rotating during powder charging, which can effectively alleviate the uneven particle size of the powder flowing out of the powder tank during powder charging, thus avoiding the phenomenon of uneven particle size of the powder inside the jacket. Using the pressure difference between the powder tank and the jacket for pressure - assisted powder charging can quickly fill the powder into the jacket.

[0032] 3) The powder feeding shaft can move freely in multiple directions (such as three directions of X, Y, and Z), enabling dense powder filling in any corner of the special - shaped jacket. Compared with the existing vibration powder - charging technology, powder filling achieved through the lifting platform and the powder feeding shaft can effectively avoid the impact on the jacket weld caused by long - term vibration, and powder can be filled at any position through the powder feeding shaft, thus effectively solving the problem that the corners of the special - shaped jacket cannot be effectively filled with powder during vibration powder charging. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings here are incorporated into the specification and form a part of this specification, and are used together with the specification to explain the principle of the present invention.

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for describing the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0035] Figure 1 It is a structural diagram of the pressure - assisted jacket powder - charging device for hot isostatic pressing provided by the present invention;

[0036] Figure 2 It is a flowchart of the powder - charging method provided by the present invention;

[0037] Figure 3 The physical drawing of the workpiece obtained by the powder loading method based on the powder loading device provided for Example 1 after hot isostatic pressing;

[0038] Figure 4 The physical drawing of the workpiece obtained by the powder loading method based on the powder loading device provided for Comparative Example 1 after hot isostatic pressing;

[0039] Figure 5 The metallographic structure diagram of the workpiece obtained for Example 1;

[0040] Figure 6 The metallographic structure diagram of the workpiece obtained for Comparative Example 1;

[0041] Figure 7 The metallographic structure diagram of the workpiece obtained for Example 2;

[0042] Figure 8 The metallographic structure diagram of the workpiece obtained for Example 3.

[0043] Wherein: 1. Cladding; 2. Fixture; 3. Lifting platform; 4. Telescopic strut; 5. Powder feeding shaft; 6. Fifth valve; 7. Third valve; 8. First valve; 9. Second pipeline; 10. First pipeline; 11. Fourth valve; 12. Powder tank; 13. Rotating blade; 14. Second valve; 15. Second branch pipeline; 16. Pressure gauge; 17. First branch pipeline; 18. Vacuum gauge; 19. Vacuum pump; 20. Inert gas replacement device; 21. Third pipeline; 22. Booster; 23. Inert gas station. Detailed implementation manners

[0044] Here, the exemplary embodiments will be described in detail. The implementation manners described in the following exemplary embodiments do not represent all implementation manners consistent with the present invention. On the contrary, they are merely examples consistent with some aspects of the present invention detailed in the appended claims.

[0045] Combined with Figure 1 As shown, the present invention provides a pressurized cladding powder loading device for hot isostatic pressing. The powder to be loaded is GH4169 alloy powder with a particle size of 15 - 150 μm, including a lifting platform 3. A cladding 1 is fixed on the lifting platform 3, and metal powder is contained in the cladding 1. A powder feeding shaft 5 with multi-degree-of-freedom movement is arranged at the top of the cladding 1, and the powder feeding shaft 5 is communicated with a powder tank 12 located above it. A vacuum port and an inert gas replacement port are respectively arranged at the top of the powder tank 12. The vacuum port is connected to a vacuum pump 19 through a vacuum pipeline, and the inert gas replacement port is connected to an inert gas replacement device 20 through an inert gas replacement pipeline. Both the vacuum pipeline and the inert gas replacement pipeline are communicated with the powder feeding shaft 5.

[0046] Furthermore, the lifting platform 3 includes a platform located above and a telescopic support 4 located below the platform, and the telescopic support 4 is driven by a cylinder to realize the lifting and lowering of the platform.

[0047] The package sleeve 1 is fixedly mounted on the lifting platform 3 by means of a clamp 2 .

[0048] Furthermore, the multi-degree-of-freedom movable powder feeding shaft 5 includes an outer layer and an inner layer: the outer layer is a stainless steel multi-joint flexible shaft, and the movement trajectory of the stainless steel multi-joint flexible shaft is controlled by a PLC controller; the inner layer is integrated with a wear-resistant plastic hose for directional conveying of metal powder.

[0049] Specifically, the PLC controller can drive the stainless steel multi-joint flexible shaft through the servo motor, support the swing of ±15° on the XYZ axis and the variable speed movement of 0-50mm / s, and the repeat positioning accuracy is ±0.1mm. The wear-resistant plastic hose is made of PTFE material with a temperature range of -50-200℃. It can achieve 15-25g / s powder flow control in conjunction with the vacuum pipeline and the inert gas replacement pipeline.

[0050] Furthermore, the vacuum pipeline includes a first pipeline 10 connected to a vacuum pump 19, the first pipeline 10 is connected to the powder feeding shaft 5 via a first valve 8, a first branch pipeline 17 is provided on the first pipeline 10, and the first branch pipeline 17 is connected to the vacuum port via a second valve 14. Preferably, a vacuum gauge 18 is also provided on the first pipeline 10 to monitor vacuum information in real time.

[0051] Furthermore, the inert gas replacement pipeline includes a second pipeline 9 connected to the inert gas replacement device 20, the second pipeline 9 is connected to the powder feeding shaft 5 via the third valve 7, and a second branch pipeline 15 is provided on the second pipeline 9, and the second branch pipeline 15 is connected to the inert gas replacement port via the fourth valve 11.

[0052] Furthermore, the inert gas replacement device 20 includes a pressure booster 22 , which is connected to the inert gas station 23 via a third pipeline 21 , and the pressure booster 22 is connected to the powder feeding shaft 5 via a second pipeline 9 and a third valve 7 .

[0053] Furthermore, a powder outlet is provided at the bottom of the powder tank 12 , and the powder outlet is connected to the powder feeding shaft 5 through a fourth pipeline, and a fifth valve 6 is provided on the fourth pipeline.

[0054] Furthermore, a pressure gauge 16 is provided on the top of the powder tank 12 to facilitate real-time monitoring of the pressure in the powder tank 12 .

[0055] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0056] Example 1

[0057] In this example, the powder loading device described above is used to load the GH4169 alloy powder with a particle size of 53 - 150 μm. Among them, the inert gas is argon, and the purity of argon is ≥99.999%. The content of gas impurities meets the following requirements: H2 < 0.5 ppm, O2 < 1.5 ppm, H2O < 3 ppm. Combining Figure 2 As shown, the powder loading process is as follows:

[0058] Step 1: Fix and install the jacket 1 on the lifting platform 3;

[0059] Step 2: Evacuate the jacket 1 and the powder tank 12: Close the inert gas replacement pipeline (close the third valve 7 and the fourth valve 11), open the vacuum pipeline (open the first valve 8 and the second valve 9), and use the vacuum pump 19 to evacuate the inside of the jacket 1 and the powder tank 12. When the vacuum gauge shows a vacuum degree < 1.0×10 -2 Pa, then close the first valve 8 and the second valve 14;

[0060] Step 3: Fill the jacket 1 and the powder tank 12 with inert gas: Open the inert gas replacement pipeline (open the third valve 7 and the fourth valve 11), and use the inert gas replacement device 20 to inject inert gas into the inside of the jacket 1 and the powder tank 12 through the inert gas replacement pipeline;

[0061] Step 4: First repeat Step 2 and Step 3 to reduce the oxygen content in the powder tank 12 and the jacket 1 by evacuating and filling with inert gas multiple times. Repeat twice in total, and then fill the powder tank 12 with inert gas alone: Keep the vacuum pipeline closed, and use the inert gas replacement device 20 to inject inert gas into the powder tank 12 through the inert gas replacement pipeline (open the fourth valve 11 and close the third valve 7) until the pressure in the powder tank 12 is 0.10 MPa;

[0062] Step 5: Evacuate the jacket 1 alone: Close the inert gas replacement pipeline (close the third valve 7 and the fourth valve 11), and use the vacuum pump 19 to evacuate the inside of the jacket 1 alone (open the first valve 8 and close the second valve 14) until the vacuum degree shown by the vacuum gauge 18 < 1.0×10 -3 Pa, then stop evacuating (close the first valve 8);

[0063] Step 6: Use a computer to perform three-dimensional modeling and three-dimensional slicing on the cavity structure inside the jacket 1;

[0064] Step 7: Set the movement path of the powder feeding shaft 5 for each slice layer according to the shape of each slice in the three-dimensional modeling.

[0065] Step 8: Start the rotating blade 13 in the powder tank 12 and set the rotation speed at 45 r / min.

[0066] Step 9: Open the fifth valve 6, and use the pressure difference to load the powder into the sheath 1. At the same time, the powder feeding shaft 5 moves according to the set movement path of each slice layer. During the powder feeding process, if the pressure in the powder tank 12 < 0.10 MPa, first close the fifth valve 6, and at the same time open the corresponding valve of the vacuum pipeline (the first valve 8), and use the vacuum pump 19 to evacuate the inside of the sheath until the vacuum degree in the sheath 1 < 5 Pa, then close the first valve 8 and stop evacuating. Then, replenish inert gas into the inside of the powder tank 12 to keep the pressure of the powder tank 12 at 0.10 MPa, and then open the powder feeding port to continue powder loading.

[0067] Step 10: After filling one layer of powder, close the powder outlet, the lifting platform 3 drives the sheath 1 to descend a specified distance, and then open the powder outlet to fill the next layer of powder until the entire inside of the sheath 1 is filled with powder.

[0068] After powder loading is completed, degassing is carried out at 450 °C. After the vacuum degree < 3.5×10 -4 Pa, the sheath 1 is sealed by welding. After degassing is completed, hot isostatic pressing is carried out. The temperature of hot isostatic pressing is 1200 °C, the pressure is 150 MPa, the holding time of temperature and pressure is 3 h, and it is cooled with the furnace to obtain the hot isostatically pressed part (one), see Figure 3 .

[0069] Comparative Example 1

[0070] As a comparative example of Example 1, in this comparative example, an annular sheath is used to load the GH4169 alloy powder with a particle size of 53 - 150 μm. The powder loading process is as follows: Fix the annular sheath on the vibrating platform, the lower powder tank is connected to the powder loading port of the sheath through a lower powder hose, the vibration frequency is 35 - 45 Hz, and continuous vibration during powder feeding ensures that the amplitude is between 2 - 3 mm. The degassing process and the hot isostatic pressing process are the same as those in Example 1.

[0071] Through Figure 3 It can be seen that by adopting the powder loading scheme of Example 1, after hot isostatic pressing, the dimensions of the parts in the direction perpendicular to the sheath nozzle and parallel to the sheath nozzle are similar (that is to say, after powder loading based on the powder loading device of the present invention and then hot isostatic pressing, due to the uniform filling of the powder, the shrinkage in all directions between the rings after hot isostatic pressing is uniform), the overall still maintains an annular shape, the shape control is good, and the grain size in the metallographic structure is uniform (see Figure 5 ). On the contrary, Figure 4, for the powder loading scheme adopted in Comparative Example 1, after hot isostatic pressing, the dimensions of the workpiece have a large difference in diameter in the direction perpendicular to the sleeve nozzle and parallel to the sleeve nozzle, presenting an overall flat-round shape, with poor shape control, and the grain size in the metallographic structure is uneven (see Figure 6 ).

[0072] Example 2

[0073] In this example, the above powder loading device is used to load the FGH4096 alloy powder with a particle size of 15 - 53 μm. Among them, argon is used as the inert gas, and the purity of argon is ≥99.999%. The gas impurity content meets the following requirements: H2 < 0.5 ppm, O2 < 1.5 ppm, H2O < 3 ppm. Combining Figure 2 as shown, the powder loading process is as follows:

[0074] Step 1: Fix and install the sleeve 1 on the lifting platform 3;

[0075] Step 2: Evacuate the sleeve 1 and the powder hopper 12: Close the inert gas replacement pipeline (close the third valve 7 and the fourth valve 11), open the vacuum pipeline (open the first valve 8 and the second valve 9), and use the vacuum pump 19 to evacuate the inside of the sleeve 1 and the powder hopper 12. When the vacuum gauge shows that the vacuum degree < 1.0×10 -2 Pa, then close the first valve 8 and the second valve 14;

[0076] Step 3: Fill the sleeve 1 and the powder hopper 12 with inert gas: Open the inert gas replacement pipeline (open the third valve 7 and the fourth valve 11), and use the inert gas replacement device 20 to inject inert gas into the inside of the sleeve 1 and the powder hopper 12 through the inert gas replacement pipeline;

[0077] Step 4: First, repeat Step 2 and Step 3 to reduce the oxygen content in the powder hopper 12 and the sleeve 1 by multiple evacuations and inert gas fillings. Repeat three times in total. Then, fill the powder hopper 12 with inert gas alone: Keep the vacuum pipeline closed, and use the inert gas replacement device 20 to inject inert gas into the powder hopper 12 through the inert gas replacement pipeline (open the fourth valve 11 and close the third valve 7) until the pressure in the powder hopper 12 is 0.15 MPa;

[0078] Step 5: Evacuate the sleeve 1 alone: Close the inert gas replacement pipeline (close the third valve 7 and the fourth valve 11), and use the vacuum pump 19 to evacuate the inside of the sleeve 1 alone (open the first valve 8 and close the second valve 14) until the vacuum degree shown by the vacuum gauge 18 < 1.0×10 -3 Pa, then stop evacuating (close the first valve 8);

[0079] Step 6: Use a computer to perform 3D modeling on the cavity structure inside the sheath 1 and conduct 3D slicing;

[0080] Step 7: Set the movement path of the powder feeding shaft 5 for each slice layer according to the shape of each slice in the 3D modeling;

[0081] Step 8: Start the rotating blade 13 inside the powder tank 12 and set the rotation speed at 55 r / min;

[0082] Step 9: Open the fifth valve 6, use the pressure difference to load the powder into the sheath 1, and at the same time, the powder feeding shaft 5 moves according to the set movement path of each slice layer; during the powder feeding process, if the pressure inside the powder tank 12 < 0.15 MPa, first close the fifth valve 6, and at the same time open the corresponding valve of the vacuum pipeline (the first valve 8), use the vacuum pump 19 to evacuate the inside of the sheath until the vacuum degree inside the sheath 1 < 5 Pa, then close the first valve 8 and stop the evacuation; then, replenish inert gas into the inside of the powder tank 12 to keep the pressure of the powder tank 12 at 0.15 MPa, and then open the powder feeding port to continue powder loading;

[0083] Step 10: After filling one layer of powder, close the powder outlet, the lifting platform 3 drives the sheath 1 to descend a specified distance, and then open the powder outlet to fill the next layer of powder until the inside of the entire sheath 1 is filled with powder.

[0084] When the powder loading is completed, degassing is carried out at 450 °C, and after the vacuum degree < 3.5×10 -4 Pa, the sheath is sealed by welding; after degassing, hot isostatic pressing is carried out. The hot isostatic pressing temperature is 1180 °C, the pressure is 120 MPa, the heat preservation and pressure holding time is 4 h, and it is cooled with the furnace to obtain the hot isostatically pressed part (II), and its metallographic structure diagram is shown in Figure 7 , and the grain size is uniform.

[0085] Example 3

[0086] In this example, the above-mentioned powder loading device is used to load the GH4099 alloy powder with a particle size of 15 - 75 μm. In principle, other inert gases except argon, such as helium, etc., can also be used as the inert gas. The specific process is as follows:

[0087] Step 1: Fix and install the sheath 1 on the lifting platform 3;

[0088] Step 2: Evacuate the sheath 1 and the powder tank 12: Close the inert gas replacement pipeline (close the third valve 7 and the fourth valve 11), open the vacuum pipeline (open the first valve 8 and the second valve 9), use the vacuum pump 19 to evacuate the inside of the sheath 1 and the powder tank 12, and when the vacuum gauge shows that the vacuum degree < 1.0×10 -2After reaching [[Pa]], close the first valve 8 and the second valve 14;

[0089] Step 3: Fill the jacket 1 and the powder tank 12 with inert gas: Open the inert gas replacement pipeline (open the third valve 7 and the fourth valve 11), and use the inert gas replacement device 20 to inject inert gas into the interior of the jacket 1 and the powder tank 12 through the inert gas replacement pipeline;

[0090] Step 4: First, repeat Step 2 and Step 3 to reduce the oxygen content in the powder tank 12 and the jacket 1 through multiple vacuum pumping and inert gas filling. Repeat three times in total, and then fill the powder tank 12 with inert gas alone: Keep the vacuum pipeline closed, and use the inert gas replacement device 20 to inject inert gas into the powder tank 12 through the inert gas replacement pipeline (open the fourth valve 11 and close the third valve 7) until the pressure in the powder tank 12 is 0.12 MPa;

[0091] Step 5: Close the inert gas replacement pipeline (close the third valve 7 and the fourth valve 11), and use the vacuum pump 19 to evacuate the interior of the jacket 1 alone (open the first valve 8 and close the second valve 14) until the vacuum degree shown by the vacuum gauge 18 < 1.0×10 -3 [[Pa]], then stop vacuum pumping (close the first valve 8);

[0092] Step 6: Use a computer to perform 3D modeling and 3D slicing on the cavity structure inside the jacket 1;

[0093] Step 7: According to the shape of each slice in the 3D modeling, set the movement path of the powder feeding shaft 5 for each slice layer;

[0094] Step 8: Start the rotating blade 13 inside the powder tank 12 and set the rotation speed at 50 r / min;

[0095] Step 9: Open the fifth valve 6, and use the pressure difference to load the powder into the jacket 1. At the same time, the powder feeding shaft 5 moves according to the set movement path for each slice layer; During the powder feeding process, if the pressure in the powder tank 12 < 0.12 MPa, first close the fifth valve 6, and at the same time open the corresponding valve of the vacuum pipeline (the first valve 8), use the vacuum pump 19 to evacuate the inside of the jacket until the vacuum degree in the jacket 1 < 5 [[Pa]], then close the first valve 8 and stop vacuum pumping; Then, replenish inert gas into the powder tank 12 to keep the pressure of the powder tank 12 at 0.12 MPa, and then open the powder feeding port to continue powder loading;

[0096] Step 10: After filling one layer of powder, close the powder outlet. The lifting platform 3 drives the jacket 1 to descend a specified distance and then open the powder outlet to fill the next layer of powder until the entire interior of the jacket 1 is filled with powder.

[0097] After powder filling, degassing is carried out at 450 °C. After the vacuum degree is < 3.5×10 -4 Pa, the sheath 1 is sealed by welding; after degassing, hot isostatic pressing is carried out. The temperature of hot isostatic pressing is 1200 °C, the pressure is 150 MPa, and the holding time for heat and pressure is 3 h. It is cooled with the furnace to obtain the hot isostatic pressed part (III), and the metallographic structure diagram thereof is shown in Figure 8 , and the grain size is uniform.

[0098] The above are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention.

[0099] It should be understood that the present invention is not limited to the content already described above, and various modifications and changes can be made without departing from its scope. The scope of the present invention is only limited by the appended claims.

Claims

1. A pressurized bag powder filling device for hot isostatic pressing, characterized in that, It includes a lifting platform (3), on which a sheath (1) is fixed, and metal powder is contained in the sheath (1); a powder feeding shaft (5) with multi-degree-of-freedom movement is arranged at the top of the sheath (1), and the powder feeding shaft (5) is communicated with a powder tank (12) located above it; a vacuum extraction port and an inert gas replacement port are respectively arranged at the top of the powder tank (12), the vacuum extraction port is connected with a vacuum pump (19) through a vacuum pipeline, the inert gas replacement port is connected with an inert gas replacement device (20) through an inert gas replacement pipeline, and the vacuum pipeline and the inert gas replacement pipeline are both communicated with the powder feeding shaft (5).

2. The pressurized bag powder filling device for hot isostatic pressing according to claim 1, characterized in that The powder feeding shaft (5) includes an outer layer and an inner layer: the outer layer is a stainless steel multi-joint flexible shaft, and the movement track of the stainless steel multi-joint flexible shaft is controlled by a PLC controller; the inner layer is integrated with a wear-resistant plastic hose for the directional transportation of metal powder.

3. The pressurized bag powder filling device for hot isostatic pressing according to claim 1, characterized in that, The vacuum pipeline includes a first pipeline (10) connected with the vacuum pump (19), the first pipeline (10) is communicated with the powder feeding shaft (5) through a first valve (8), a first branch pipeline (17) is arranged on the first pipeline (10), and the first branch pipeline (17) is communicated with the vacuum extraction port through a second valve (14).

4. The pressurized bag powder filling device for hot isostatic pressing according to claim 1, wherein, The inert gas replacement pipeline includes a second pipeline (9) connected with the inert gas replacement device (20), the second pipeline (9) is communicated with the powder feeding shaft (5) through a third valve (7), a second branch pipeline (15) is arranged on the second pipeline (9), and the second branch pipeline (15) is connected with the inert gas replacement port through a fourth valve (11).

5. The pressurized bag powder filling device for hot isostatic pressing according to claim 4, characterized in that, The inert gas replacement device (20) includes a supercharger (22), the supercharger (22) is connected with an inert gas station (23) through a third pipeline (21), and the supercharger (22) is connected with the powder feeding shaft (5) through the second pipeline (9) and the third valve (7).

6. The pressurized bag powder filling device for hot isostatic pressing according to claim 1, characterized in that, An outlet powder port is arranged at the bottom of the powder tank (12), the outlet powder port is communicated with the powder feeding shaft (5) through a fourth pipeline, and a fifth valve (6) is arranged on the fourth pipeline.

7. The pressurized package powder loading device for hot isostatic pressing according to claim 6, characterized in that, A pressure gauge (16) is arranged at the top of the powder tank (12).

8. A powder loading method for a pressurized bag powder loading device for hot isostatic pressing according to any one of claims 1 to 7 above, characterized in that, Specifically, it includes the following steps: Step 1: Fix and install the sheath (1) on the lifting platform (3); Step 2: Evacuate the sheath (1) and the powder tank (12): Close the inert gas replacement pipeline, open the vacuum pipeline, and use the vacuum pump (19) to evacuate the inside of the sheath (1) and the powder tank (12) until the vacuum degree meets the requirements, and then close the vacuum pipeline; Step 3: Fill the sheath (1) and the powder tank (12) with inert gas: Open the inert gas replacement pipeline, and use the inert gas replacement device (20) to inject inert gas into the inside of the sheath (1) and the powder tank (12) through the inert gas replacement pipeline. Step 4: Repeat Step 2 and Step 3 multiple times to reduce the oxygen content in the powder hopper (12) and the jacket (1) by multiple vacuum pumping and inert gas filling. Then, fill the powder hopper (12) with inert gas alone: keep the vacuum pipeline closed, and use the inert gas replacement device (20) to inject inert gas into the powder hopper (12) through the inert gas replacement pipeline until the pressure in the powder hopper (12) is within the range of 0.10 - 0.15 MPa. Step 5. Separately evacuating the jacket (1): Close the inert gas replacement pipeline, and use a vacuum pump (19) to separately evacuate the inside of the jacket (1) until the vacuum degree is < 1.0×10 -3 Pa, and then stop evacuating; Step 6: Perform 3D modeling and 3D slicing on the cavity structure inside the jacket (1). Step 7: Set the movement path of each slice layer of the powder feeding shaft (5) according to the shape of each slice in the 3D modeling. Step 8: Start the rotating blade (13) inside the powder hopper (12) and set the rotation speed at 45 - 55 r / min. Step 9: Open the fifth valve (6), and use the pressure difference to load the powder into the jacket (1). At the same time, the powder feeding shaft (5) moves according to the set movement path of each slice layer. Step 10: After filling one layer of powder, close the powder outlet. The lifting platform (3) drives the jacket (1) to descend a specified distance and then opens the powder outlet to fill the next layer of powder until the entire inside of the jacket (1) is filled with powder.

9. The powder loading method according to claim 8, characterized in that, The inert gas is argon, and the purity of the argon is ≥99.999%. The gas impurity content meets the following requirements: H2 < 0.5 ppm, O2 < 1.5 ppm, H2O < 3 ppm.

10. The powder filling method according to claim 8, characterized in that, In Step 9, during the entire pressurized powder loading process, if the pressure in the powder hopper (12) < 0.10 MPa, first close the fifth valve (6), and at the same time open the corresponding valve of the vacuum pipeline. Use the vacuum pump (19) to evacuate the inside of the jacket (1) until the vacuum degree inside the jacket (1) < 5 Pa, then close the corresponding valve of the vacuum pipeline and stop the vacuum pumping. Then, replenish inert gas into the powder hopper (12) to keep the pressure in the powder hopper (12) at 0.10 - 0.15 MPa, and then open the powder outlet to continue the powder loading.

Images