A method for producing a TiAl alloy casting containing return material

Abstract

The application discloses a preparation method of TiAl alloy castings containing return materials, and the TiAl alloy return materials used by the application are castings pouring gates, subsidies and condensate cut off in subsequent processing, and the specific implementation steps are as follows: the return materials are subjected to ultrasonic cleaning and surface treatment to remove the surface oxide layer, new materials with a target weight of 50% are used to smelt a primary ingot in primary smelting, the return materials are placed under the primary ingot after turning over before secondary smelting, and then smelting and pouring are carried out to preheated molds to form castings, the application realizes recycling of TiAl alloy raw materials, reduces 50% of raw material cost and 33% of preparation cost, reduces power consumption and equipment loss, and thus the purpose of energy saving and emission reduction is achieved. The impurity element of the cast ingot produced by the method is controlled to be equivalent to that of the alloy produced by conventional raw material production, and compared with a direct raw material preparation process, the method is convenient and fast. The castings poured out are uniform in composition, compact in structure and high in purity.

Description

Technical Field

[0001] This invention belongs to the field of titanium-aluminum alloy casting, and specifically relates to a method for preparing TiAl alloy castings containing recycled materials. Background Technology

[0002] TiAl alloys are considered ideal high-temperature structural materials for aerospace applications, possessing low density, high strength, good oxidation resistance, creep resistance, and excellent fatigue performance. They have significant potential for engineering applications, particularly suitable for critical components such as turbine blades and compressor blades that require materials to withstand extremely high stress and temperature. While meeting strength requirements, they can significantly reduce component weight and improve fuel efficiency. However, the production cost of TiAl alloys is much higher than that of ordinary steel and aluminum alloys, making their widespread adoption in cost-sensitive applications difficult. The high cost of TiAl alloys mainly stems from complex refining processes and low metal yield. Due to the high content of reactive elements in TiAl alloys, the preparation process is complex, time-consuming, and energy-intensive. Furthermore, the poor fluidity of this intermetallic compound makes it prone to defects such as shrinkage cavities, porosity, and gas pores. Solving these problems in the casting process mainly relies on setting gates and padding, resulting in significant raw material waste and a reduced metal yield. In severe cases, the weight of the casting may only be one-tenth of the melted weight, further increasing the difficulty of producing TiAl alloy castings.

[0003] The machining of castings leaves behind a large amount of recycled material, mainly including gates and patches, which account for more than 70% of the total weight of the casting. Recycling this recycled material is much cheaper than directly using raw materials such as sponge Ti and Nb-Al master alloys. Moreover, if this recycled material is not recycled, it must be scrapped, resulting in significant resource waste. However, due to the difficulty of cold working titanium-aluminum alloys and the susceptibility to oxidation and surface contamination during hot working, recycling recycled material is challenging. Domestic research in this area mainly focuses on the purification of recycled material, as seen in patents CN119500677A and CN119804524A, with no reports on its specific application in semi-suspended vacuum induction casting.

[0004] The method for preparing high-temperature alloys using recycled materials in patent CN201810810949.6 involves a complex pickling + alkali washing + shot peening process. It uses strong acids and alkalis, which poses certain operational risks and has a long operation cycle. It is not suitable for titanium-aluminum alloys, is easily contaminated by elements such as O, N and H, and cannot minimize the risk of impurities. Summary of the Invention

[0005] To address the issue of high manufacturing costs for titanium-aluminum alloy castings, the present invention aims to provide a method for preparing TiAl alloy castings containing recycled materials.

[0006] The specific technical solution adopted in this invention is as follows: a method for preparing TiAl alloy castings containing recycled material. During the preparation process, the raw materials include virgin material and recycled TiAl alloy material, specifically including the following steps:

[0007] Step 1: Prepare new material according to the TiAl alloy composition, with the new material accounting for 50% of the target weight of the raw materials;

[0008] Step 2: Under a protective atmosphere, slowly increase the power to the maximum power and perform vacuum induction melting on the new material placed in the water-cooled copper crucible. After the new material in the crucible has completely melted, keep it at the temperature for 15 minutes. Then, reduce the power at a rate of 120kW / min to allow the ingot to cool down with the water-cooled copper crucible. After the power is reduced to the minimum, turn off the heating power. After the ingot has cooled down, take it out to obtain a first ingot.

[0009] Step 3: The ultrasonically cleaned return material is surface treated and placed at the bottom of the water-cooled copper crucible, and the original ingot is flipped and placed on top of the return material;

[0010] Step 4: Remelt the alloy again. The process is as follows: Under a protective atmosphere, slowly increase the power to the maximum power. After the alloy in the crucible is completely melted, hold it at the temperature for 15 minutes. Then pour it into a preheated stainless steel mold. After the casting cools, take it out to obtain a TiAl alloy casting with the required dimensions.

[0011] Furthermore, the TiAl alloy return material is used for the TiAl alloy casting gates, patches, and solidified shells cut off during subsequent processing.

[0012] Furthermore, the TiAl alloy is Ti(43-48)Al(1-13)Nb.

[0013] Furthermore, the TiAl alloy is Ti45Al8Nb.

[0014] Furthermore, new materials were prepared according to the composition of the TiAl alloy, using sponge Ti, high-purity Al blocks, and Nb-Al intermediate alloy particles as metal raw materials.

[0015] Furthermore, in steps 2 and 4, the protective atmosphere is high-purity argon, and the vacuum degree is maintained at 0.05 MPa.

[0016] Furthermore, ultrasonic cleaning uses a mixture of rosin and alcohol in a 1:5 mass ratio.

[0017] Furthermore, surface treatment refers to the sequential sandblasting and polishing to remove the surface oxide layer.

[0018] Furthermore, the preheated stainless steel mold is heated to 600℃.

[0019] Compared with existing technologies, this invention provides a method for preparing TiAl alloy castings containing recycled material. In the first melting process, only 50% of the target weight of new material is placed. Due to the low total heat of the melt and the slow heating rate of the cooling water, electromagnetic stirring is performed at the highest power for 15 minutes. Subsequently, the power is rapidly reduced to 120 kW / min to obtain a smooth primary ingot. In the second melting process, 50% of the target weight of recycled material is placed at the bottom of the crucible, and the primary ingot is placed on top of the recycled material. Here, the electromagnetic force is more concentrated, resulting in better electromagnetic stirring. The number of melting passes required to prepare castings of the same quality is reduced from three to two. This method combines a semi-suspended melting process with a gravity casting process, using recycled material to replace the raw material for the casting's solidification shell, gating, and patching parts. While reducing raw material costs by 50% and preparation costs by 33%, this method yields high-quality TiAl alloy castings with uniform composition, a difference of less than ±0.2 wt% between ingots of major elements, oxygen and iron content controlled below 350 ppm, and carbon, hydrogen, and nitrogen content controlled below 100 ppm. Attached Figure Description

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0021] Figure 1 This is a physical image of the return material and primary ingot placement described in step 6 of Example 1.

[0022] Figure 2 This is a schematic diagram of TiAl alloy casting.

[0023] Figure 3 (a) is a macroscopic morphology view of the side of the Ti45Al8Nb alloy primary ingot prepared in Example 1. (b) is a macroscopic morphology view of the bottom of the Ti45Al8Nb alloy primary ingot prepared in Example 2.

[0024] (c) is a macroscopic morphology of the top of the Ti45Al8Nb alloy primary ingot prepared in Example 3. (d) is a macroscopic morphology of the bottom of the Ti45Al8Nb alloy primary ingot prepared in Example 4.

[0025] Figure 4 (a) is a macroscopic morphological image of the Ti45Al8Nb alloy casting produced in Example 1. (b) is a macroscopic morphological image of the Ti45Al8Nb alloy casting produced in Example 4.

[0026] Figure 5 (a) is a microscopic image of the Ti45Al8Nb alloy casting produced in Example 1. (b) is a microscopic image of the Ti45Al8Nb alloy casting produced in Example 4.

[0027] Figure 6(a) shows the macroscopic morphology of the return material before cleaning, and (b) shows the macroscopic morphology of the return material after cleaning. Detailed Implementation

[0028] The present application will be further described below with reference to specific embodiments.

[0029] It should be noted that terms such as "upper", "lower", "left", "right", and "middle" used in this specification are only for clarity of description and are not intended to limit the scope of implementation. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered as within the scope of this application.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the term “and / or” as used herein includes any and all combinations of one or more of the associated listed items.

[0031] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0032] As used herein, the term “about” is used to provide for the flexibility and imprecision associated with a given term, measure, or value. Those skilled in the art can readily determine the degree of flexibility for a particular variable.

[0033] As used herein, the term “at least one of…” is intended to be synonymous with “one or more of…”. For example, “at least one of A, B, and C” explicitly includes only A, only B, only C, and combinations thereof.

[0034] Machining titanium-aluminum alloys is technically challenging. During cutting, the high strength and low thermal conductivity of titanium-aluminum alloys lead to rapid tool wear, high cutting forces, and easy overheating and hardening of the machined surface, ultimately affecting the dimensional accuracy and surface quality of the workpiece. Traditional cutting tools and methods struggle to address these issues, often requiring tools made of special materials (such as cemented carbide or ceramic tools) and sophisticated cooling and lubrication systems. Often, the cut scraps retain significant amounts of water-soluble wire cutting fluid and black machine oil. Ultrasonic cleaning with a rosin-containing cleaning solution is based on the principle of "like dissolves like." The organic solvents (such as aliphatic hydrocarbons and aromatic compounds) in the rosin can dissolve the hydrocarbons in the oil, effectively removing the contaminants.

[0035] During vacuum induction melting, the magnetic field penetrating through the gaps in the water-cooled copper crucible suspends the melt, causing most of the melt to float under electromagnetic confinement. However, when the melt mass is large and there are no magnetically permeable gaps at the bottom of the crucible, a portion of the melt will deposit at the bottom. Upon contact with the water-cooled crucible base, it forms a solidified shell. This shell protects the melt from reacting with the crucible but also reduces metal utilization. Utilizing this characteristic, this invention designs a process where only 50% of the target weight of new material is placed during a single melting cycle, resulting in a low total heat of the melt and improved protection of the magnetic field. The cooling water in the crucible heats up more slowly, allowing for safe heat preservation for 15 minutes at maximum power before gradually reducing the power to 120kW. This avoids the hump phenomenon, resulting in a smooth primary ingot surface, facilitating the placement of subsequent ingots. During the secondary melting and casting process, 50% of the target weight of return material is placed at the bottom. This combines the suspension melting process with gravity casting. Due to the sequential pouring of gravity casting (bottom-up filling), the return material at the bottom of the crucible replaces the raw material as a solidified shell, casting gate, and fills the upper part of these castings, significantly reducing the raw material cost of casting (see...). Figure 2 Furthermore, since the primary smelting ingot is placed on top of the return material, the electromagnetic force is more concentrated here, resulting in better electromagnetic stirring and significantly improving smelting efficiency. Compared to low-density raw materials such as sponge titanium and aluminum blocks, the return material is also easier to melt under electromagnetic induction. When the cooling water reaches the same temperature, the faster the raw material melts, the longer the electromagnetic stirring time can be provided for the melt. Under the same time, the temperature of the equipment cooling water is lower, which can effectively reduce the risk of equipment overheating, reduce equipment wear, and lower production costs.

[0036] Example 1

[0037] The method for preparing a TiAl alloy casting containing recycled material as described in this embodiment includes the following steps:

[0038] (1) According to the atomic ratio of Ti:0.47, Al:0.45, Nb:0.08, 4279g of high-purity sponge Ti, 1845g of high-purity Al block and 1876g of Nb-Al intermediate alloy particles were accurately weighed, with a total mass of 8000g of metal raw materials.

[0039] (2) Select 8000g of returned material and place them in an ultrasonic cleaner. Add the prepared cleaning solution (rosin / alcohol = 1 / 5) to the ultrasonic cleaner to thoroughly clean the material. After cleaning and drying, sandblast the surface and polish it with an angle grinder.

[0040] (3) Before smelting, the inside of the copper crucible must be cleaned with alcohol to ensure that it is free of impurities. The materials should be stacked according to specific requirements. Based on the temperature field and magnetic field analysis of the solidification furnace, the low melting point elements should be placed at the bottom of the crucible during the first smelting, and the high melting point elements should be placed at the top to maximize the utilization of heating power.

[0041] (4) Turn on the low-pressure cooling water, dryer, mechanical pump and argon cylinder switches in sequence; close the hatch and lock the latch; turn on the mechanical pump and large and small Roots pumps to evacuate the vacuum, then turn on the diffusion pump, preheat to 280°C, and evacuate to a vacuum level of 5. 10 -3 Pa; turn off the diffusion pump, open the gas filling valve, and fill with argon gas to maintain the vacuum degree of the melting chamber at 0.05 MPa.

[0042] (5) Turn on the cooling water system and the heating power, and slowly increase the power to heat the metal raw material placed in the water-cooled copper crucible. After the raw material in the crucible has completely melted, keep it at that temperature for 15 minutes. Then, reduce the power at a rate of 120 kW / min to allow the ingot to cool down with the water-cooled copper crucible. After the power is reduced to the minimum, turn off the heating power. After the ingot has cooled down, take it out to obtain a first ingot. At this time, preheat the casting mold to 600°C.

[0043] (6) The returned material (its macroscopic morphology is shown in the figure) Figure 6 (a) After ultrasonic cleaning and surface treatment with the prepared cleaning solution (rosin / alcohol = 1 / 5), its macroscopic morphology is shown in (see [reference]). Figure 6 (b) of the above-mentioned ingot is placed at the bottom of the crucible and then placed on top of the return material after the ingot is flipped over (see [reference]). Figure 1 Place the preheated 600℃ mold in the pouring position and fix it in place. Turn on the low-pressure cooling water, dryer, mechanical pump, and argon cylinder switches in sequence. Close the hatch and lock the latch. Turn on the mechanical pump and the large and small Louvius pumps to evacuate the vacuum. Then turn on the diffusion pump, preheat to 280℃, and evacuate to a vacuum level of 5. 10 -3 Pa; turn off the diffusion pump, open the gas filling valve, and fill with argon gas to maintain the vacuum degree of the melting chamber at 0.05 MPa; turn on the cooling water system, turn on the heating power supply, slowly increase the power to the maximum power, and after the metal is completely melted, keep it at the temperature for 15 minutes, and then pour it into the preheated stainless steel mold. After the casting cools down, take it out to obtain a TiAl alloy casting with the required dimensions.

[0044] Among them, macroscopic morphology photos of a single casting ingot are as follows: Figure 3 As shown in (a) above, the macroscopic morphology of the final cast TiAl alloy part is as follows. Figure 4As shown in (a) above, the composition test results of the alloy casting are shown in Table 1. The target composition design values ​​are Al: 28.86 wt.%; Nb: 17.66 wt.%. The oxygen and iron contents can be controlled below 350 ppm, and the carbon, hydrogen, and nitrogen contents can be controlled below 100 ppm.

[0045] Table 1 Chemical composition of Ti45Al8Nb alloy bars (wt.%)

[0046]

[0047] Example 2

[0048] The method for preparing a TiAl alloy casting containing recycled material as described in this embodiment includes the following steps:

[0049] (1) According to the atomic ratio of Ti:0.47, Al:0.45, Nb:0.08, accurately weigh 4279g of high-purity sponge Ti, 1845g of high-purity Al block and 1876g of Nb-Al intermediate alloy particles, and the total mass of metal raw material 1 is 8000g.

[0050] (2) According to the atomic ratio of Ti:0.47, Al:0.45, Nb:0.08, accurately weigh 4279g of high-purity sponge Ti, 1845g of high-purity Al block and 1876g of Nb-Al intermediate alloy particles, and the total mass of metal raw material 2 is 8000g.

[0051] (3) Before smelting, the inside of the copper crucible must be cleaned with alcohol to ensure that it is free of impurities. The materials should be stacked according to specific requirements. Based on the temperature field and magnetic field analysis of the solidification furnace, the low melting point elements should be placed at the bottom of the crucible during the first smelting, and the high melting point elements should be placed at the top to maximize the utilization of heating power.

[0052] (4) Turn on the low-pressure cooling water, dryer, mechanical pump and argon cylinder switches in sequence; close the hatch and lock the latch; turn on the mechanical pump and large and small Roots pumps to evacuate the vacuum, then turn on the diffusion pump, preheat to 280°C, and evacuate to a vacuum level of 5. 10 -3 Pa; turn off the diffusion pump, open the gas filling valve, and fill with argon gas to maintain the vacuum degree of the melting chamber at 0.05 MPa.

[0053] (5) Turn on the cooling water system and the heating power, and slowly increase the power to heat the metal raw material 1 placed in the water-cooled copper crucible. After the raw material in the crucible has completely melted, keep it at that temperature for 15 minutes. Then, reduce the power at a rate of 120 kW / min to allow the ingot to cool down with the water-cooled copper crucible. After the power is reduced to the minimum, turn off the heating power. After the ingot has cooled down, take it out to obtain a first ingot. At this time, preheat the casting mold to 600°C.

[0054] (6) Place the metal raw material 2 at the bottom of the crucible, and place the ingot, which was flipped over once, on top of the metal raw material 2. Place the preheated 600°C mold at the pouring position and fix it. Turn on the low-pressure cooling water, dryer, mechanical pump and argon cylinder switches in sequence; close the hatch and lock the latch; turn on the mechanical pump and large and small Roots pumps to evacuate the vacuum, then turn on the diffusion pump, preheat to 280°C, and evacuate to a vacuum degree of 5. 10 -3 Pa; turn off the diffusion pump, open the gas filling valve, and fill with argon gas to maintain the vacuum degree of the melting chamber at 0.05 MPa; turn on the cooling water system, turn on the heating power supply, slowly increase the power to the maximum power, and after the metal is completely melted, keep it at the temperature for 15 minutes, and then pour it into the preheated stainless steel mold. After the casting cools down, take it out to obtain a TiAl alloy casting with the required dimensions.

[0055] Its primary ingot macroscopic morphology photographs are as follows Figure 3 As shown in (b) above, the final macroscopic morphology photograph of the casting is as follows. Figure 4 As shown in (b) above, the component detection results are shown in Table 2.

[0056] Table 2 Chemical composition of Ti45Al8Nb alloy bars (wt.%)

[0057]

[0058] Example 3

[0059] The method for preparing a TiAl alloy casting containing recycled material as described in this embodiment includes the following steps:

[0060] (1) According to the atomic ratio of Ti:0.47, Al:0.45, Nb:0.08, 4279g of high-purity sponge Ti, 1845g of high-purity Al block and 1876g of Nb-Al intermediate alloy particles were accurately weighed, with a total mass of 8000g of metal raw materials.

[0061] (2) Select 8000g of returned material and place them in an ultrasonic cleaner. Add the prepared cleaning solution (rosin / alcohol = 1 / 5) to the ultrasonic cleaner to thoroughly clean the material. After cleaning and drying, sandblast the surface and polish it with an angle grinder.

[0062] (3) Before smelting, the inside of the copper crucible must be cleaned with alcohol to ensure that it is free of impurities. Place 8000g of return material into the crucible.

[0063] (4) Turn on the low-pressure cooling water, dryer, mechanical pump and argon cylinder switches in sequence; close the hatch and lock the latch; turn on the mechanical pump and large and small Roots pumps to evacuate the vacuum, then turn on the diffusion pump, preheat to 280°C, and evacuate to a vacuum level of 5. 10 -3 Pa; turn off the diffusion pump, open the gas filling valve, and fill with argon gas to maintain the vacuum degree of the melting chamber at 0.05 MPa.

[0064] (5) Turn on the cooling water system and the heating power supply, and slowly increase the power to heat the return material placed in the water-cooled copper crucible. After the return material in the crucible has completely melted, keep it at that temperature for 15 minutes. Then, reduce the power supply at a rate of 120 kW / min to allow the melt to cool down with the water-cooled copper crucible. After the power is reduced to the minimum, turn off the heating power supply. After the ingot has cooled down, take it out to obtain a primary ingot. At this time, preheat the casting mold to 600°C.

[0065] (6) Place 8000g of new material at the bottom of the crucible, and place the ingot, which was flipped over, on top of the new material. Place the preheated 600℃ mold at the pouring position and fix it. Turn on the low-pressure cooling water, dryer, mechanical pump and argon cylinder switches in sequence; close the hatch and lock the latch; turn on the mechanical pump and large and small Roots pumps to evacuate the vacuum, then turn on the diffusion pump, preheat to 280℃, and evacuate to a vacuum degree of 5. 10 -3 Pa; turn off the diffusion pump, open the gas filling valve, and fill with argon gas to maintain the vacuum degree of the melting chamber at 0.05 MPa; turn on the cooling water system, turn on the heating power supply, slowly increase the power to the maximum power, and after the metal is completely melted, keep it at the temperature for 15 minutes, and then pour it into the preheated stainless steel mold. After the casting cools down, take it out to obtain a TiAl alloy casting with the required dimensions.

[0066] The results of component detection at multiple locations are shown in Table 3.

[0067] Table 3 Chemical composition of Ti45Al8Nb alloy bars (wt.%)

[0068]

[0069] Example 4

[0070] The method for preparing a TiAl alloy casting containing recycled material as described in this embodiment includes the following steps:

[0071] (1) Select 8000g of recycled material and place them in an ultrasonic cleaner. Add the prepared cleaning solution (rosin / alcohol = 1 / 5) to the ultrasonic cleaner to thoroughly clean the material. After cleaning and drying, sandblast the surface and polish it with an angle grinder to obtain recycled material 1.

[0072] (2) Select 8000g of recycled material and place them in an ultrasonic cleaner. Add the prepared cleaning solution (rosin / alcohol = 1 / 5) to the ultrasonic cleaner to thoroughly clean the material. After cleaning and drying, sandblast the surface and polish it with an angle grinder to obtain recycled material 2.

[0073] (3) Before smelting, the inside of the copper crucible must be cleaned with alcohol to ensure that it is free of impurities. Place 8000g of return material 1 into the crucible.

[0074] (4) Turn on the low-pressure cooling water, dryer, mechanical pump and argon cylinder switch in sequence; close the hatch and lock the latch; turn on the mechanical pump and large and small Roots pump to evacuate, then turn on the diffusion pump, preheat to 280°C, and evacuate to a vacuum of 5×10-3 Pa; turn off the diffusion pump, open the charging valve, and charge argon to keep the vacuum of the melting chamber at 0.05 MPa.

[0075] (5) Turn on the cooling water system and the heating power, and slowly increase the power to heat the return material 1 placed in the water-cooled copper crucible. After the raw material in the crucible has completely melted, keep it at the temperature for 15 minutes, and then reduce the power at a rate of 120 kW / min to allow the ingot to cool down with the water-cooled copper crucible. After the power is reduced to the minimum, turn off the heating power. After the ingot has cooled down, take it out to obtain a primary ingot. At this time, preheat the casting mold to 600°C.

[0076] (6) Place the return material 2 at the bottom of the crucible, and place the ingot after the first casting is flipped on top of the return material 2. Place the preheated 600℃ mold at the pouring position and fix it. Turn on the low-pressure cooling water, dryer, mechanical pump and argon cylinder switch in sequence; close the hatch and lock the latch; turn on the mechanical pump and large and small Roots pump to evacuate the vacuum, then turn on the diffusion pump, preheat to 280℃, and evacuate to a vacuum degree of 5×10-3 Pa; turn off the diffusion pump, open the charging valve, and charge argon to keep the vacuum degree of the melting chamber at 0.05Mpa; turn on the cooling water system, heat the power supply, and slowly increase the power to the maximum power. After the metal is completely melted, keep it at the temperature for 15 minutes, and then pour it into the preheated stainless steel mold. After the casting cools, take it out to obtain a TiAl alloy casting with the required dimensions. The composition test results at multiple locations are shown in Table 4.

[0077] Table 4 Chemical composition of Ti45Al8Nb alloy bars (wt.%)

[0078]

[0079] This invention enables the recycling and reuse of TiAl alloys, reducing production costs and achieving energy conservation and emission reduction. The impurity element control in ingots produced using this method is comparable to that of alloys produced using conventional raw materials, and the process is more convenient and faster than directly using raw materials. It saves production costs and improves smelting efficiency. This invention allows for the more convenient and faster production of alloy castings with high purity and low impurity content.

[0080] The above embodiments are merely preferred embodiments of the present invention, but the implementation of the present invention is not limited to the above embodiments. Any changes, modifications, substitutions, or combinations made without departing from the spirit and principle of the present invention, such as various combinations of solutions in the embodiments, should be considered equivalent replacements and are all within the protection scope of the present invention.

Claims

1. A method for producing a TiAl alloy casting containing return material, characterized in that, In the preparation process, the raw materials include new materials and TiAl alloy return materials, and the preparation process specifically includes the following steps. Step 1: The new materials are prepared according to the TiAl alloy composition, and the new materials account for 50% of the target weight of the raw materials; Step 2: Under a protective atmosphere, the power is slowly increased to the highest power, and the new materials placed in the water-cooled copper crucible are subjected to vacuum induction melting. After the new materials in the crucible are completely melted, the power is maintained for 15 minutes, and the power is reduced at a rate of 120 kW / min, and the ingot is cooled with the water-cooled copper crucible. After the power is reduced to the lowest, the heating power is turned off, and after the ingot is cooled, it is taken out, and a primary ingot is obtained; Step 3: The return materials after ultrasonic cleaning are subjected to surface treatment and placed at the bottom of the water-cooled copper crucible, and the primary ingot is placed at the top of the return materials after being turned over; Step 4: The melting process is performed again, which is: under a protective atmosphere, the power is slowly increased to the highest power, and after the alloy in the crucible is completely melted, the power is maintained for 15 minutes, and then poured into a preheated stainless steel mold. After the casting is cooled, it is taken out, and a TiAl alloy casting with a size meeting the requirements is obtained.

2. The method of claim 1, wherein, The TiAl alloy return material is a sprue, a subsidy and a skull cut off during subsequent processing of the TiAl alloy casting.

3. The method of claim 1, wherein, The TiAl alloy is Ti(43-48)Al(1-13)Nb.

4. The method of claim 1, wherein, The TiAl alloy is Ti45Al8Nb.

5. The method of claim 1, wherein, The new materials are prepared according to the TiAl alloy composition, and the new materials use sponge Ti, high-purity Al blocks and Nb-Al intermediate alloy particles as metal raw materials.

6. The method of claim 1, wherein, In steps 2 and 4, the protective atmosphere is high-purity argon, and the vacuum degree is maintained at 0.05 Mpa.

7. The method of claim 1, wherein, The ultrasonic cleaning uses a mixture of rosin water and alcohol with a mass ratio of 1 / 5.

8. The method of claim 1, wherein, The temperature of the preheated stainless steel mold is 600°C.

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