Method for preparing high-purity GH4169 alloy by adding return scrap

Abstract

The invention discloses a method for preparing a high-purity GH4169 alloy by adding return scraps, and belongs to the technical field of alloy smelting, the method comprises the following steps: step S1, placing a B2O3-containing composite purifying agent, the GH4169 return scraps and a rare earth alloy hydride in a high-vacuum or high-purity argon protection heat treatment furnace; the composite purifying agent containing B2O3 is composed of a B2O3 inner core and a CaF2-AlF3 shell, s2, heating to 1000-1150 DEG C, preserving heat for 1-15 hours, then heating to 1400 DEG C, and preserving heat for 5-10 minutes; and S3, after finishing, cooling along with the furnace to obtain the treated GH4169 return scrap. S4, the treated GH4169 return scrap and the treated GH4169 alloy are remelted, and the high-purity GH4169 alloy is obtained; according to the method, the removal effect of nitrogen and oxygen in the GH4169 alloy return scrap is improved by adding the rare earth alloy hydride.

Description

Technical Field

[0001] This invention belongs to the field of alloy smelting technology, specifically relating to a method for preparing high-purity GH4169 alloy by adding recycled materials. Background Technology

[0002] GH4169 alloy is a precipitation-strengthened nickel-based superalloy with γ" and γ' phases as the main strengthening phases. It exhibits excellent yield strength, tensile strength, fatigue resistance, oxidation resistance, and corrosion resistance within a temperature range of -253 to 650℃, as well as good machinability and weldability. It is widely used in the manufacture of key load-bearing components in aero-engines, spacecraft, nuclear power equipment, and petrochemical industries. With the continuous development of the high-end equipment manufacturing industry, the market demand for GH4169 alloy continues to grow. The efficient recycling and reuse of the large amount of recycled materials (including chips, waste castings, and scrapped parts) generated during its production, processing, and service is of significant economic and social value for reducing raw material consumption, controlling production costs, and achieving resource recycling.

[0003] However, the high-value recycling of recycled materials is limited by the deterioration of their metallurgical purity. Compared with virgin materials, GH4169 recycled materials mainly have the following technical problems during multiple recycling processes: Enrichment of gaseous elements and inclusions: During the initial melting of the alloy, carbon can react with gaseous elements such as oxygen and nitrogen to generate gaseous products that escape, achieving self-purification of the melt. Returned material is usually difficult to repeat this deep degassing process during remelting, leading to the accumulation of gaseous elements such as oxygen and nitrogen. Supersaturated gaseous elements precipitate during the solidification stage, forming brittle non-metallic inclusions such as high-melting-point oxides (e.g., Al2O3) and nitrides (e.g., TiN), as well as solidification defects such as shrinkage cavities and microporous structures.

[0004] Microstructural degradation and performance decline: The aforementioned non-metallic inclusions and solidification defects act as stress concentration sources, disrupting the continuity of the alloy microstructure. With the increase in the proportion of recycled materials, the number of oxide inclusions in the alloy increases, and the low-melting-point Laves phase is enriched and coarsened at grain boundaries and between dendrites, significantly reducing the room temperature and high temperature mechanical properties of the alloy, especially plasticity and fatigue life.

[0005] Limitations of existing purification technologies: Currently, the main industrial method for processing recycled materials is to mix them with virgin materials at a low proportion (usually less than 30%) and then remelt them (e.g., vacuum induction melting, electroslag remelting). While traditional processes can achieve partial purification, their efficiency in removing micron- and submicron-sized stable inclusions already present in the recycled materials is limited, especially in effectively removing chemically stable nitrides (such as TiN). This necessitates strict control over the proportion of recycled materials added during production, restricting the utilization rate of recycled materials and making it difficult to guarantee the performance stability of alloys with a high proportion of recycled materials.

[0006] Therefore, there is an urgent need to develop a purification technology that can remove dissolved and combined oxygen and nitrogen impurities from GH4169 recycled material. This technology should be characterized by not introducing secondary pollution and not damaging the composition of the base alloy. It should be able to act directly on the recycled material under solid or semi-solid conditions to avoid component loss and energy consumption caused by remelting. At the same time, it should achieve highly selective deep purification of oxygen and nitrogen elements, and the purified products should be stable and easy to separate. Summary of the Invention

[0007] The purpose of this invention is to provide a method for preparing high-purity GH4169 alloy by adding recycled materials, so as to solve the problem of low purification effect of oxygen and nitrogen elements in GH4169 alloy recycled materials.

[0008] The objective of this invention can be achieved through the following technical solutions: This invention provides a method for preparing high-purity GH4169 alloy by adding recycled materials, comprising the following steps: Step S1: Place the B2O3-containing composite purifying agent, GH4169 recycled material and rare earth alloy hydride in a heat treatment furnace protected by high vacuum or high-purity argon; the B2O3-containing composite purifying agent consists of a B2O3 core and a CaF2-AlF3 shell. Step S2: Heat to 1000-1150℃ and hold for 1-15 hours; this is lower than the initial melting temperature of GH4169, but sufficient to ensure rapid diffusion of hydrogen and impurity elements. The hydrogen in the getter is activated and diffuses into the interior of GH4169, combining with oxygen and nitrogen atoms at the lattice or grain boundaries and capturing them to form stable rare earth metal oxides, nitrides, etc.; then heat to 1400℃ and hold for 5-10 minutes. Step S3: After completion, the material is cooled in the furnace to obtain the processed GH4169 return material; Step S4: Remelt the processed GH4169 return material and GH4169 alloy to obtain high-purity GH4169 alloy.

[0009] Furthermore, the mass percentage of treated GH4169 recycled material in the high-purity GH4169 alloy is 0.01%–100%.

[0010] Furthermore, the high-purity GH4169 alloy contains 65% recycled GH4169 by mass. For GH4169 alloys containing 20%, 40%, 60%, 80%, and 100% recycled material, the yield strength was tested and found to be below 65%; the preferred GH4169 alloy composition is 65% recycled material. The purified recycled material, due to its improved purity and microstructure, can be reused at a rate of up to 65% or even higher during remelting without compromising the mechanical properties and reliability of the final high-purity GH4169 alloy.

[0011] Furthermore, the amount of the B2O3-containing composite purifying agent added is 8%–12% of the mass of the GH4169 recycled material; The amount of rare earth alloy hydride added is 3%–8% of the mass of GH4169 recycled material.

[0012] Furthermore, the rare earth alloy hydride is prepared by the following steps: Rare earth metals and alloy metals are smelted and mechanically crushed to a particle size of 50-500 μm under nitrogen conditions. After pulverization, they undergo hydrogenation treatment. Following hydrogenation, they are mechanically crushed to 50-200 μm under vacuum in a hydrogenation furnace to utilize hydrogen embrittlement. Then, they are ball-milled to 1-10 μm under nitrogen protection. Ball milling can be selected as the mechanical crushing method.

[0013] Furthermore, the rare earth metal is cerium; the alloy metal is at least one of nickel and calcium.

[0014] Furthermore, the conditions for the hydrogenation treatment include: 300–500°C and 1–5 MPa hydrogen pressure.

[0015] Different alloy metals can have their preparation process parameters adjusted according to their physicochemical properties, such as hydrogenation temperature, pressure, raw material ratio, etc.

[0016] The Ce-Ni melting temperature is 1480~1520℃, and the hydrogenation conditions are: temperature 300-350℃, hydrogen pressure 2-3MPa. The Ce-Ca melting temperature is 850-900℃, and the hydrogenation conditions are: temperature 400-500℃ and hydrogen pressure 3-5MPa. The Ce-Ni-Ca smelting temperature is 1480~1520℃. Ce-Ni is melted first, and then Ca is added. Hydrogenation conditions: temperature 250-350℃, hydrogen pressure 1-3MPa.

[0017] Furthermore, when the alloy metal is nickel, the molar ratio of Ce to Ni is 1:5; When the alloy metal is calcium, the molar ratio of Ce to Ca is 1:2; When the alloy metal is nickel and calcium, the molar ratio of Ce, Ni and Ca is 2:7:0.5-2.

[0018] Furthermore, the oxygen content in the GH4169 recycled material is 0.025–0.035 wt%; the nitrogen content in the GH4169 recycled material is 0.010–0.020 wt%. The oxygen and nitrogen contents in the GH4169 recycled material are 3–5 times those in the virgin alloy. After treatment with the purification agent described in this invention, the oxygen and nitrogen contents in the recycled material are reduced, achieving a purity level comparable to that of the virgin material.

[0019] Furthermore, the mass ratio of the outer shell to the core is 20-30:1.

[0020] Furthermore, the B2O3-containing composite purifying agent is prepared through the following steps: Under inert atmosphere, B2O3 powder, CaF2 powder and AlF3 powder are mixed and ball-milled for 2-4 hours. Then, they are pressed into blocks or sheets at a temperature of 150-250℃ and pressure of 10-20MPa. After that, they are kept at 250-300℃ for 1-2 hours. After the heat preservation is completed, they are crushed and sieved to obtain B2O3 composite purifying agent.

[0021] In the preparation of the B2O3 composite purifying agent, the cold welding effect of ball milling is first utilized to achieve mechanical composite of B2O3 powder with CaF2 powder and AlF3 powder, forming an embedded coating structure. The principle of mechanical composite is that B2O3 powder is softer than CaF2 powder and AlF3 powder. After low-temperature solidification, the viscous rheology of B2O3 is used to achieve interparticle bonding without melting, thus obtaining the B2O3 composite purifying agent. The B2O3 core has a strong adsorption and dissolution capacity for oxide inclusions such as Al2O3 and SiO2, which can effectively remove primary and secondary oxides generated during the smelting of recycled materials. The CaF2-AlF3 shell not only lowers the melting point and viscosity in the melt, promoting the collision, growth and floating of inclusions, but its lower density also makes it easier to form a covering layer on the surface of the alloy liquid, which has the effect of heat preservation and preventing oxidation. Moreover, the slag shell formed after solidification is easy to remove, preventing the purifying agent itself from becoming a source of inclusions.

[0022] The beneficial effects of this invention are: This invention provides a method for preparing high-purity GH4169 alloy by adding recycled materials. This method improves the removal efficiency of nitrogen and oxygen in the recycled GH4169 alloy by adding rare earth alloy hydrides. The rare earth alloy hydrides are prepared by hydrogenation of rare earth metals and alloy metals; the B2O3-containing composite purifier consists of a B2O3 core and a CaF2-AlF3 shell.

[0023] In this invention, rare earth alloy hydrides and B2O3-containing composite purifiers synergistically enhance the purification effect. When heated in a vacuum or inert atmosphere, the rare earth alloy hydrides release active hydrogen atoms, which diffuse into the GH4169 return material and react with oxygen and nitrogen atoms dissolved in the crystal lattice or segregated at grain boundaries to form stable compounds, achieving deep purification from the inside out. Subsequently, during the remelting stage, the B2O3-containing composite purifier plays a role in melt purification. Its B2O3 core effectively adsorbs and dissolves oxides, while the CaF2-AlF3 outer shell regulates the physicochemical properties of the melt. Together, they further remove non-metallic inclusions from the melt, forming a complete and efficient purification closed loop. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] Obviously, the following description is merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios without any inventive effort. Furthermore, it is understood that although the effort involved in such development may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, any changes to design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as insufficient disclosure of the content of this application.

[0026] However, there may be instances where unnecessary detailed descriptions are omitted. For example, detailed descriptions of well-known matters or repetitive descriptions of essentially the same structure may be omitted. This is to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art. Furthermore, the following description is provided to enable those skilled in the art to fully understand this application and is not intended to limit the subject matter of the claims.

[0027] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions, and all technical features and optional technical features of this application can be combined to form new technical solutions.

[0028] The following is a detailed description of a method for preparing high-purity GH4169 alloy by adding recycled materials according to an embodiment of this application.

[0029] The following is a detailed description with reference to specific examples.

[0030] The main alloying element contents in the GH4169 recycled material are as follows: Ni 53.31wt%, Cr 19.27wt%, Fe 17.02wt%, Nb 4.21wt%, Mo 2.74wt%, Ti 0.81wt%, Al 0.52wt%, others. In the following examples and comparative examples, the oxygen content in the GH4169 recycled material is 0.035wt%; the nitrogen content in the GH4169 recycled material is 0.020wt%.

[0031] Example 1

[0032] This embodiment provides a method for preparing high-purity GH4169 alloy by adding recycled materials, including the following steps: Step S1: Place the B2O3-containing composite purifying agent, GH4169 recycled material, and rare earth alloy hydride in an argon-protected heat treatment furnace; the amount of B2O3-containing composite purifying agent added is 10% of the mass of GH4169 recycled material; the amount of rare earth alloy hydride added is 5% of the mass of GH4169 recycled material.

[0033] Step S2: Heat to 1000℃ and hold for 10 hours, then raise the temperature to 1400℃ and hold for 5 minutes; Step S3: After completion, the material is cooled in the furnace to obtain the processed GH4169 return material; Step S4: Remelt the processed GH4169 recycled material and GH4169 alloy to obtain high-purity GH4169 alloy; the mass ratio of processed GH4169 recycled material in the high-purity GH4169 alloy is 65%.

[0034] Rare earth alloy hydrides are prepared through the following steps: Rare earth metals and alloy metals are smelted and ball-milled under nitrogen to a particle size of 50-500 μm. After pulverization, they are hydrogenated. After hydrogenation, a vacuum is drawn in the hydrogenation furnace, and the particles are mechanically crushed to 50-200 μm using hydrogen embrittlement. Then, they are ball-milled to 1-10 μm under nitrogen protection. The rare earth metal is cerium, and the alloy metal is calcium. The Ce-Ca smelting temperature is 850-900℃, the hydrogenation temperature is set at 450℃, and the hydrogen pressure is 4 MPa. The molar ratio of Ce to Ca is 1:2. A B2O3-containing composite purifier consists of a B2O3 core and a CaF2-AlF3 shell; the mass ratio of shell to core is 25:1, and the mass ratio of CaF2 to AlF3 is 1:1; the B2O3-containing composite purifier is prepared through the following steps: Under inert atmosphere, B2O3 powder, CaF2 powder and AlF3 powder are mixed and ball-milled for 3 hours. Then, they are pressed into blocks or sheets at 200℃ and pressure of 15MPa. After that, they are kept at 300℃ for 1 hour. After the heat preservation is completed, they are crushed and sieved to obtain B2O3 composite purifying agent with a particle size of 100-200 μm.

[0035] Example 2

[0036] This embodiment provides a method for preparing high-purity GH4169 alloy by adding recycled materials, including the following steps: Step S1: Place the B2O3-containing composite purifying agent, GH4169 recycled material, and rare earth alloy hydride in an argon-protected heat treatment furnace; the amount of B2O3-containing composite purifying agent added is 8% of the mass of GH4169 recycled material; the amount of rare earth alloy hydride added is 3% of the mass of GH4169 recycled material.

[0037] Step S2: Heat to 1000℃ and hold for 10 hours, then raise the temperature to 1400℃ and hold for 5 minutes; Step S3: After completion, the material is cooled in the furnace to obtain the processed GH4169 return material; Step S4: Remelt the processed GH4169 recycled material and GH4169 alloy to obtain high-purity GH4169 alloy; the mass ratio of processed GH4169 recycled material in the high-purity GH4169 alloy is 65%.

[0038] The rare earth alloy hydride is the same as in Example 1; The B2O3-containing composite purifying agent is the same as in Example 1.

[0039] Example 3

[0040] This embodiment provides a method for preparing high-purity GH4169 alloy by adding recycled materials, including the following steps: Step S1: Place the B2O3-containing composite purifying agent, GH4169 recycled material, and rare earth alloy hydride in an argon-protected heat treatment furnace; the amount of B2O3-containing composite purifying agent added is 12% of the mass of GH4169 recycled material; the amount of rare earth alloy hydride added is 8% of the mass of GH4169 recycled material.

[0041] Step S2: Heat to 1000℃ and hold for 10 hours, then raise the temperature to 1400℃ and hold for 5 minutes; Step S3: After completion, the material is cooled in the furnace to obtain the processed GH4169 return material; Step S4: Remelt the processed GH4169 recycled material and GH4169 alloy to obtain high-purity GH4169 alloy; the mass ratio of processed GH4169 recycled material in the high-purity GH4169 alloy is 65%.

[0042] The rare earth alloy hydride is the same as in Example 1; The B2O3-containing composite purifying agent is the same as in Example 1.

[0043] Example 4

[0044] The difference between this embodiment and Embodiment 1 is that the B2O3 composite purifying agent is different: A B2O3-containing composite purifier consists of a B2O3 core and a CaF2-AlF3 shell; the mass ratio of shell to core is 30:1, and the mass ratio of CaF2 to AlF3 is 1:1; the B2O3-containing composite purifier is prepared through the following steps: Under inert atmosphere, B2O3 powder, CaF2 powder and AlF3 powder are mixed and ball-milled for 3 hours. Then, they are pressed into blocks or sheets at 200℃ and pressure of 15MPa. After that, they are kept at 300℃ for 1 hour. After the heat preservation is completed, they are crushed and sieved to obtain B2O3 composite purifying agent with a particle size of 100-200 μm.

[0045] The remaining raw materials and preparation process are the same as in Example 1.

[0046] Example 5

[0047] The difference between this embodiment and Embodiment 1 is that the B2O3 composite purifying agent is different: A B2O3-containing composite purifier consists of a B2O3 core and a CaF2-AlF3 shell; the mass ratio of shell to core is 20:1, and the mass ratio of CaF2 to AlF3 is 1:1; the B2O3-containing composite purifier is prepared through the following steps: Under inert atmosphere, B2O3 powder, CaF2 powder and AlF3 powder are mixed and ball-milled for 3 hours. Then, they are pressed into blocks or sheets at 200℃ and pressure of 15MPa. After that, they are kept at 300℃ for 1 hour. After the heat preservation is completed, they are crushed and sieved to obtain B2O3 composite purifying agent with a particle size of 100-200 μm.

[0048] The remaining raw materials and preparation process are the same as in Example 1.

[0049] Example 6

[0050] The difference between this embodiment and Embodiment 1 lies in the rare earth alloy hydride. Specifically, the rare earth alloy hydride is prepared through the following steps: Rare earth metals and alloy metals are smelted and ball-milled under nitrogen to a particle size of 50-500 μm. After pulverization, they are hydrogenated. After hydrogenation, a vacuum is drawn in the hydrogenation furnace, and the particles are mechanically crushed to 50-200 μm using hydrogen embrittlement. Then, they are ball-milled to 1-10 μm under nitrogen protection. The rare earth metal is cerium, and the alloy metal is nickel. The Ce-Ni smelting temperature is 1480-1520℃, and the hydrogenation conditions are: temperature set at 300℃, hydrogen pressure at 2 MPa, and the molar ratio of Ce to Ni is 1:5.

[0051] The remaining raw materials and preparation process are the same as in Example 1.

[0052] Example 7

[0053] The difference between this embodiment and Embodiment 1 lies in the rare earth alloy hydride. Specifically, the rare earth alloy hydride is prepared through the following steps: Rare earth metals and alloy metals are smelted and ball-milled under nitrogen to a particle size of 50-500 μm. After pulverization, they are hydrogenated. After hydrogenation, a vacuum is drawn in the hydrogenation furnace, and the particles are mechanically crushed to 50-200 μm using hydrogen embrittlement. Then, they are ball-milled to 1-10 μm under nitrogen protection. The rare earth metal is cerium, and the alloy metals are nickel and calcium. The Ce-Ni-Ca smelting temperature is 1480-1520℃. Ce-Ni is melted first, and then Ca is added. The hydrogenation conditions are set at a temperature of 300℃ and a hydrogen pressure of 2 MPa. The molar ratio of Ce, Ni, and Ca is 2:7:1.

[0054] The remaining raw materials and preparation process are the same as in Example 1.

[0055] Example 8

[0056] The difference between this embodiment and Embodiment 1 lies in the rare earth alloy hydride. Specifically, the rare earth alloy hydride is prepared through the following steps: Rare earth metals and alloy metals are smelted and ball-milled under nitrogen to a particle size of 50-500 μm. After pulverization, they are hydrogenated. After hydrogenation, a vacuum is drawn in the hydrogenation furnace, and the particles are mechanically crushed to 50-200 μm using hydrogen embrittlement. Then, they are ball-milled to 1-10 μm under nitrogen protection. The rare earth metal is cerium, and the alloy metals are nickel and calcium. The Ce-Ni-Ca smelting temperature is 1480-1520℃. Ce-Ni is melted first, and then Ca is added. The hydrogenation conditions are set at a temperature of 300℃ and a hydrogen pressure of 2 MPa. The molar ratio of Ce, Ni, and Ca is 2:7:2.

[0057] The remaining raw materials and preparation process are the same as in Example 1.

[0058] Comparative Example 1

[0059] The difference between this comparative example and Example 1 is that the B2O3-containing composite purifier is replaced with a mixture of CaF2 and AlF3 in a mass ratio of 25:25:2.

[0060] The remaining raw materials and preparation process are the same as in Example 1.

[0061] Comparative Example 2

[0062] The difference between this comparative example and Example 1 is that the rare earth alloy hydride in Example 1 is replaced with a rare earth alloy, i.e., no hydrogenation treatment is performed. The preparation steps are as follows:

[0063] Rare earth metals and alloy metals are smelted and ball-milled under nitrogen to a particle size of 1-10 μm. After pulverization, they are hydrogenated. After hydrogenation, a vacuum is drawn in the hydrogenation furnace, and the particles are mechanically crushed to 50-200 μm using hydrogen embrittlement. Then, they are ball-milled to 1-10 μm under nitrogen protection. The rare earth metal is cerium, and the alloy metal is calcium. The Ce-Ca smelting temperature is 850-900℃, the hydrogenation temperature is set at 450℃, and the hydrogen pressure is 4 MPa. The molar ratio of Ce to Ca is 1:2.

[0064] The remaining raw materials and preparation process are the same as in Example 1.

[0065] Comparative Example 3

[0066] This comparative example is based on Comparative Example 2, except that the B2O3-containing composite purifying agent is replaced with a mixture of CaF2, AlF3 and B2O3 in a mass ratio of 25:25:2. The remaining raw materials and preparation process are the same as those in Comparative Example 2.

[0067] The treated recycled materials from Examples 1-8 and Comparative Examples 1-3 were tested using glow discharge mass spectrometry and an oxygen and nitrogen analyzer to determine macroscopic elemental composition and oxygen and nitrogen content. The results are shown in Table 1 below: Table 1

[0068] According to Table 1 and Examples 1-8 and Comparative Examples 1-3, the present invention improves the removal efficiency of nitrogen and oxygen in GH4169 alloy recycled material by adding rare earth alloy hydrides. The rare earth alloy hydrides consume oxygen and nitrogen atoms dissolved in the crystal lattice or segregated at grain boundaries in the GH4169 recycled material. The B2O3-containing composite purifier effectively adsorbs and removes oxides and nitrides from the alloy melt, thereby reducing the oxygen and nitrogen content of the recycled alloy. The core-shell structure ensures that the B2O3 core does not melt and leak prematurely at the purifier's operating temperature, thus extending the effective action time of the purifier and improving the purification efficiency. The oxygen and nitrogen content in the GH4169 recycled material can be significantly reduced to levels comparable to virgin alloys, with oxygen content decreasing from 0.025-0.035 wt% to below 0.005 wt% and nitrogen content decreasing from 0.010-0.020 wt% to below 0.003 wt%.

[0069] Test case

[0070] The alloy samples prepared in Example 1 and Comparative Examples 1-3 were subjected to performance tests. The test samples were Φ6mm×9mm in size, and the room temperature mechanical properties were tested on a universal testing machine.

[0071] The results are shown in Table 2: Table 2

[0072] As shown in Table 2, the rare earth alloy hydrides added in this invention not only remove nitrogen and oxygen, but the residual rare earth metals also improve the mechanical properties of the high-purity GH4169 alloy. Compared to Comparative Examples 1-3, the embodiments of this invention utilize rare earth hydrides to achieve deep removal of interstitial atoms in the solid-state stage, preparing a clean matrix for subsequent melting. In Comparative Example 2, the raw materials used were not hydrogenated, resulting in a relatively high oxygen content, which is not conducive to improving mechanical properties. In the early purification stage, the core-shell composite purifier plays an important role in specifically removing native inclusions generated in the melt and inclusions that have not been completely decomposed. In Comparative Examples 1 and 3, the uncoated mixtures have different densities and melting sequences, which easily cause local non-uniformity in melt composition and temperature, and the high viscosity B2O3 slag easily leads to inclusions. The core-shell structure, as a relatively homogeneous reaction unit, enhances its dispersion stability in the melt. The shell composition (CaF2-AlF3) itself helps regulate slag fluidity and interfacial tension, promoting the flotation of purified products and slag-metal separation, significantly reducing the risk of residual purifying agent. The probability of harmful side reactions between excessive residual rare earth elements and flux is greatly reduced. Trace amounts of residual rare earth elements, such as cerium, can uniformly dissolve in the alloy matrix, refining grains, purifying grain boundaries, and strengthening through microalloying. This directly improves the room-temperature plasticity, creep strength, and fatigue resistance of the final alloy while simultaneously purifying impurities.

[0073] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0074] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing high-purity GH4169 alloy by adding recycled materials, characterized in that, Includes the following steps: Step S1: Place the B2O3-containing composite purifying agent, GH4169 recycled material and rare earth alloy hydride in a heat treatment furnace protected by high vacuum or high-purity argon; the B2O3-containing composite purifying agent consists of a B2O3 core and a CaF2-AlF3 shell. Step S2: Heat to 1000-1150℃ and hold for 1-15 hours, then raise the temperature to 1400℃ and hold for 5-10 minutes; Step S3: After completion, the material is cooled in the furnace to obtain the processed GH4169 return material; Step S4: Remelt the processed GH4169 return material and GH4169 alloy to obtain high-purity GH4169 alloy.

2. The method for preparing high-purity GH4169 alloy by adding recycled materials according to claim 1, characterized in that, The high-purity GH4169 alloy contains 0.01%–100% recycled GH4169 material after processing.

3. The method for preparing high-purity GH4169 alloy by adding recycled materials according to claim 1, characterized in that, The high-purity GH4169 alloy contains 65% recycled GH4169 material after processing.

4. The method for preparing high-purity GH4169 alloy by adding recycled materials according to claim 1, characterized in that, The amount of the B2O3-containing composite purifying agent added is 8%-12% of the mass of the GH4169 recycled material; The amount of rare earth alloy hydride added is 3%–8% of the mass of GH4169 recycled material.

5. The method for preparing high-purity GH4169 alloy by adding recycled material according to claim 1, characterized in that, The rare earth alloy hydride is prepared by the following steps: Rare earth metals and alloy metals are smelted and mechanically crushed to a particle size of 50-500μm under nitrogen conditions. After crushing, they are hydrogenated. After hydrogenation, a vacuum is drawn in the hydrogenation furnace, and the particles are crushed to 1-10μm.

6. The method for preparing high-purity GH4169 alloy by adding recycled material according to claim 1, characterized in that, The rare earth metal is cerium; the alloy metal is at least one of nickel and calcium.

7. The method for preparing high-purity GH4169 alloy by adding recycled material according to claim 1, characterized in that, The conditions for hydrogenation treatment include: 300–500°C and 1–5 MPa hydrogen pressure.

8. The method for preparing high-purity GH4169 alloy by adding recycled material according to claim 1, characterized in that, The oxygen content in the GH4169 recycled material is 0.025–0.035 wt%; the nitrogen content in the GH4169 recycled material is 0.010–0.020 wt%.

9. The method for preparing high-purity GH4169 alloy by adding recycled materials according to claim 1, characterized in that, The mass ratio of the outer shell to the core is 20-30:

1.

10. The method for preparing high-purity GH4169 alloy by adding recycled material according to claim 1, characterized in that, The B2O3-containing composite purifying agent is prepared through the following steps: Under inert atmosphere, B2O3 powder, CaF2 powder and AlF3 powder are mixed and ball-milled for 2-4 hours. Then, they are pressed into blocks or sheets at a temperature of 150-250℃ and pressure of 10-20MPa. After that, they are kept at 250-300℃ for 1-2 hours. After the heat preservation is completed, they are crushed and sieved to obtain B2O3 composite purifying agent.

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