Method for preparing GH4079 nickel-based superalloy rod based on cold combined fast forging and radial forging

Abstract

The application discloses a method for preparing GH4079 nickel-based high-temperature alloy rods based on combined fast forging and radial forging cooling, adopts a combined fast forging and radial forging cooling mode, breaks coarse as-cast structures through fast forging and obtains fast-forged blank with uniform size, utilizes the multi-directional high-frequency forging characteristics of a radial forging machine, avoids cracking of the GH4079 alloy in the hot working process, and obtains GH4079 nickel-based high-temperature alloy rods with uniform grain structures. The application realizes high-quality forging of the GH4079 nickel-based high-temperature alloy, solves the problem of uneven edge structures of the alloy, improves the product yield, and meets the harsh requirements of an aero-engine on high-performance turbine discs and other key components.

Description

Technical Field

[0001] This invention relates to the field of hot working technology for difficult-to-deform nickel-based superalloys, and more specifically, to a method for preparing GH4079 nickel-based superalloy bars based on a combination of fast forging and radial forging. Background Technology

[0002] With the development of the aviation industry, the thrust-to-weight ratio of engines is constantly increasing, and the operating temperature of engine components is also constantly rising. Materials play a crucial role in their research and development. Nickel-based superalloys are the main materials for turbine disks in current aero-engines. To adapt to higher operating temperatures, the γ′ phase content of these materials is constantly increasing. However, a γ′ content exceeding 40% is considered a difficult-to-deform superalloy. Although this can bring high performance to the superalloy, it also increases the difficulty of alloy processing and preparation.

[0003] GH4079 alloy is a typical high-temperature alloy that is difficult to deform and is widely used in turbine disks and compressor disks of aero engines. The total content (wt.%) of Al, Ti, and Nb in the alloy is as high as 8.5%, the total content (wt.%) of W and Mo is 7%, and the upper limit of C content (wt.%) reaches 0.08%, resulting in a volume fraction of γ′ precipitation strengthening phase as high as 45%. Due to the high degree of alloying, segregation is prone to occur in the ingot, leading to uneven distribution of the γ′ phase between dendrites and dendrite trunks and the aggregation of MC carbides. This results in the forging temperature window of GH4079 alloy being only about 80℃, making it extremely prone to cracking during the forging process. In severe cases, it can lead to the scrapping of the entire part, resulting in low yield and high production cost. Therefore, the forging process of GH4079 alloy is a key bottleneck restricting the subsequent development of disk forgings.

[0004] The forging process, as a crucial step in the modal transformation of alloys from the cast to the forged state, is vital for difficult-to-deform high-temperature alloys like GH4079. Currently, for GH4079 alloy, the main domestic method used is a multi-stage upsetting and drawing process using a high-speed forging machine. Chinese Patent Publication No. CN120290998 A proposes a method to improve forging cracking in GH4079 alloy. This method utilizes high-speed forging equipment for multi-stage axial upsetting and drawing, mainly by controlling parameters such as heating, holding, forging deformation, and cooling methods in each stage of forging to achieve forging blanking of the ingot and significantly reduce the cracking problem of GH4079 alloy during hot working. However, this technology focuses on reducing the occurrence of forging cracks and solving the problem of "forgeability" of GH4079 alloy, and does not meet the higher requirements for microstructure and property control and improved yield of key components such as engine turbine disks and compressor disks.

[0005] In view of the above, there is an urgent need to study a new technology that can achieve a breakthrough from "forgeable" to "well-forged" GH4079 nickel-based alloy, improving the uniformity of the microstructure and increasing the product yield while ensuring formability. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide a method for preparing GH4079 nickel-based high-temperature alloy bars based on a combination of fast forging and radial forging. This method achieves high-quality forging of GH4079 alloy by combining fast forging and radial forging, solves the problem of uneven microstructure at the alloy edges, and improves the product yield, thus meeting the stringent requirements of aero-engines for key components such as high-performance turbine disks.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] This invention provides a method for preparing GH4079 nickel-based superalloy bars based on a combination of rapid forging and radial forging, comprising the following steps:

[0009] S1, fast forging, is the process of forging GH4079 alloy ingots into fast forging billets through multiple heat treatments.

[0010] S11, GH4079 alloy ingot is held at 1140℃~1180℃ for 240min~300min, and then forged by axial upsetting in multiple cycles, controlling the total deformation of a single cycle to be 20%~40%, to obtain octagonal cross-section billet A;

[0011] S12, the billet A is held at 1120℃~1160℃ for 180min~240min, and axial upsetting and drawing forging is carried out in one cycle, with the total deformation controlled at 25%~35%, to obtain octagonal cross-section billet B;

[0012] S13, the billet B is held at 1120℃~1160℃ for 180min~240min, and axial elongation is carried out in one cycle, with the total deformation controlled at 20%~30%, to obtain the fast forging billet;

[0013] S2, after the fast forging billet is air-cooled to room temperature, it is subjected to full peeling and grinding to obtain the intermediate billet;

[0014] S3, radial forging: The intermediate billet is fed into the furnace at 550℃~600℃, heated to 880℃~920℃ and held for 420min~480min, then heated to 1120℃~1160℃ and held for 300min~360min, followed by multiple passes of radial forging, controlling the total deformation to ≥50%, and air-cooled to obtain GH4079 nickel-based high-temperature alloy bars with an edge grain size difference of <3 levels.

[0015] Preferably, in step S11, the GH4079 alloy ingot is prepared by a dual process of vacuum induction melting and vacuum arc remelting.

[0016] Preferably, in step S11, the chemical composition of the GH4079 alloy ingot, by mass percentage, is as follows: carbon: 0.04%~0.08%, cobalt: 12.5%~16.0%, chromium: 10%~12%, titanium: 2.4%~3.0%, aluminum: 2.8%~3.3%, tungsten: 2.0%~3.0%, molybdenum: 4.0%~5.0%, niobium: 2.5%~3.0%, vanadium: 0. 4%~0.8%, silicon ≤0.4%, iron ≤1.0%, manganese ≤0.4%, phosphorus ≤0.015%, sulfur ≤0.010%, cerium ≤0.01%, boron ≤0.01%, lanthanum ≤0.05%, neodymium ≤0.05%, magnesium ≤0.05%, lead ≤0.001%, tin ≤0.0012%, arsenic ≤0.0025%, antimony ≤0.0025%, bismuth ≤0.0001%, and the remainder is nickel.

[0017] Preferably, in step S11: the forging process employs at least two cycles of axial upsetting.

[0018] Preferably, during the rapid forging in step S1 and the radial forging in step S3, the surface of the billet is covered with insulating cotton during each forging pass.

[0019] Preferably, in step S3, during the radial forging, the deformation amount per pass is controlled to be 10%~20%, and the total number of passes is 3~5.

[0020] Preferably, in step S3, the specifications of the GH4079 nickel-based high-temperature alloy bar are Φ210mm~Φ240mm.

[0021] Preferably, in step S3, the GH4079 nickel-based high-temperature alloy bar has a room temperature tensile strength ≥1400MPa, a room temperature yield strength ≥960MPa, a room temperature impact energy ≥44J, a hardness ≥380HB, a grain size of 3.0±1 at the center and R / 2 position, and a grain size of 4.5 to 7.0 at the edge.

[0022] The method for preparing GH4079 nickel-based superalloy bars based on a combination of rapid forging and radial forging provided by this invention has the following beneficial effects:

[0023] 1. Due to the temperature sensitivity of the original fast forging process, the microstructure of the forged bar is uneven, especially at the edges (grain size difference greater than 4 levels). This invention effectively improves the microstructure uniformity of the forged bar (edge ​​grain size difference less than 3 levels) through a combination of fast forging and radial forging cold processing. At the same time, it can significantly improve the product yield, thereby meeting the stringent requirements of aero-engines for key components such as high-performance turbine disks. It also provides a feasible solution for the microstructure and performance control and efficient preparation of difficult-to-deform high-temperature alloys, laying a solid technical foundation for promoting the application research of related materials.

[0024] 2. This invention breaks down the coarse as-cast structure through rapid forging to obtain a billet with a uniform structure and appropriate size. Then, it uses radial forging with a total deformation of more than 50% to prepare a forged bar. By utilizing the multi-directional high-frequency forging characteristics of the radial forging machine, it avoids cracking during the hot working process of GH4079 nickel-based high-temperature alloy while obtaining a uniform grain structure.

[0025] 3. Compared with the traditional fast forging process, this invention effectively suppresses the initiation and propagation of surface cracks in GH4079 nickel-based superalloy bars during forging, significantly reduces the machining loss of black-skinned bars, effectively improves the yield of products, improves the microstructure uniformity of GH4079 nickel-based superalloy bars, and enhances the comprehensive mechanical properties of GH4079 nickel-based superalloy bars.

[0026] 4. This invention achieves effective control over the microstructure evolution during the forging of difficult-to-deform high-temperature alloys by adjusting key process parameters such as heating temperature, holding time, deformation per heat stroke, and cooling method during hot working. Simultaneously, the use of a combined fast forging and radial forging cold forging method, with multiple hammers synchronously and symmetrically striking the billet radially, places the billet under multi-directional compressive stress, which can suppress crack initiation and propagation. Furthermore, the radial forging mill, with its higher striking frequency and high-speed deformation, reduces the critical deformation for dynamic recrystallization, making it easier to trigger recrystallization nucleation. Thus, building upon the initial improvement in microstructure uniformity achieved by fast forging, radial forging further obtains a more uniform fine-grained microstructure across the entire bar cross-section. This invention effectively improves the yield of the product while ensuring excellent microstructure uniformity and comprehensive mechanical properties of the forged bar, contributing to the application of GH4079 nickel-based high-temperature alloys. Attached Figure Description

[0027] Figure 1 This is a process flow diagram of the method for preparing GH4079 nickel-based high-temperature alloy bars based on the cold combined forging and radial forging of the present invention;

[0028] Figure 2 In the figure, (a) is the cross-section of GH4079 nickel-based superalloy black bar prepared by fast forging process in the comparative example, and (b) is the cross-section of GH4079 nickel-based superalloy black bar prepared by cold combination of fast forging and radial forging in the embodiment of the present invention.

[0029] Figure 3 In the figures, (a) is the cross-section of a GH4079 nickel-based superalloy smooth bar prepared by fast forging process in the comparative example, and (b) is the cross-section of a GH4079 nickel-based superalloy smooth bar prepared by fast forging and radial forging in the embodiment of the present invention. Detailed Implementation

[0030] To better understand the above-mentioned technical solutions of the present invention, the technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0031] To address the characteristics of GH4079 nickel-based superalloy, such as a narrow hot working window and poor high-temperature plasticity, this invention employs a combined forging method of fast forging and radial forging. Fast forging breaks down the coarse as-cast structure and yields a billet with a uniform structure and appropriate size. Then, radial forging with a total deformation of ≥50% is used to prepare a forged bar. By utilizing the multi-directional high-frequency forging characteristics of the radial forging machine, cracking during the hot working process of GH4079 nickel-based superalloy is avoided while obtaining a uniform grain structure.

[0032] Combination Figure 1 As shown, this invention provides a method for preparing GH4079 nickel-based superalloy bars based on a combination of rapid forging and radial forging, comprising the following steps:

[0033] S1, fast forging, is the process of forging GH4079 alloy ingots into fast forging billets through multiple heat treatments.

[0034] This step is a rapid forging process, which uses a rapid forging machine to forge and break up the coarse as-cast structure, thereby obtaining a rapid forging billet with a uniform structure.

[0035] S11, GH4079 alloy ingot is held at 1140℃~1180℃ for 240min~300min, and then forged by axial upsetting in multiple cycles, controlling the total deformation of a single cycle to be 20%~40%, to obtain octagonal cross-section billet A;

[0036] In this step, the GH4079 alloy ingot is produced using a dual process of vacuum induction melting and vacuum arc remelting. Its chemical composition, by mass percentage, is as follows: carbon: 0.04%~0.08%, cobalt: 12.5%~16.0%, chromium: 10%~12%, titanium: 2.4%~3.0%, aluminum: 2.8%~3.3%, tungsten: 2.0%~3.0%, molybdenum: 4.0%~5.0%, niobium: 2.5%~3%. 0%, Vanadium: 0.4%~0.8%, Silicon ≤0.4%, Iron ≤1.0%, Manganese ≤0.4%, Phosphorus ≤0.015%, Sulfur ≤0.010%, Cerium ≤0.01%, Boron ≤0.01%, Lanthanum ≤0.05%, Neodymium ≤0.05%, Magnesium ≤0.05%, Lead ≤0.001%, Tin ≤0.0012%, Arsenic ≤0.0025%, Antimony ≤0.0025%, Bismuth ≤0.0001%, and the remainder is Nickel.

[0037] GH4079 alloy ingots are held at 1140℃~1180℃ for 240min~300min to allow the precipitated phases in the ingot microstructure to remelt and transform into a single-phase microstructure, improving its hot workability. Then, multiple cycles of axial upsetting and drawing are used for forging to break down the coarse as-cast microstructure. The total deformation per cycle is 20%~40%, yielding an octagonal cross-section billet A. One cycle of axial upsetting and drawing refers to a process where the ingot is initially heated and held at the original temperature, then upset along the ingot's axial direction, followed by reheating and holding in the furnace before axial elongation. In this specific implementation, the forging process in this step uses two cycles of axial upsetting and drawing.

[0038] S12, the billet A is held at 1120℃~1160℃ for 180min~240min, and axial upsetting and drawing forging is carried out in one cycle, with the total deformation controlled at 25%~35%, to obtain octagonal cross-section billet B;

[0039] In this step, the billet A is subjected to one cycle of axial upsetting forging at a temperature lower than the forging temperature in step S11, in order to refine the grain structure.

[0040] S13, the billet B is held at 1120℃~1160℃ for 180min~240min, and axial elongation is carried out in one cycle, with the total deformation controlled at 20%~30%, to obtain the fast forging billet;

[0041] In this step, axial elongation is performed in one cycle at 1120℃~1160℃, and the total deformation is strictly controlled to be 20%~30%. The purpose is to obtain a fast forging billet that meets the requirements of radial forging deformation.

[0042] During the forging process in steps S11 to S13 above, insulation cotton is wrapped around the surface of the billet during each forging to reduce the temperature drop of the billet surface.

[0043] S2, after the fast forging billet is air-cooled to room temperature, it is subjected to full peeling and grinding to obtain the intermediate billet;

[0044] The purpose of this step, which involves full peeling and grinding, is to ensure the removal of surface defects from the blank.

[0045] S3, radial forging: The intermediate billet is fed into the furnace at 550℃~600℃, heated to 880℃~920℃ and held for 420min~480min, then heated to 1120℃~1160℃ and held for 300min~360min, followed by multiple passes of radial forging, controlling the total deformation amount of the passes to ≥50%, and air-cooled to obtain GH4079 nickel-based high-temperature alloy bars with an edge grain size difference of <3 levels.

[0046] In this radial forging step, the deformation per pass is controlled at 10%~20%, and the total number of passes is 4. During each forging pass, insulating cotton is wrapped around the surface of the billet to reduce the surface temperature drop.

[0047] The GH4079 nickel-based superalloy rods prepared above have a specification of Φ210mm~Φ240mm and their properties are as follows: room temperature tensile strength ≥1400MPa, room temperature yield strength ≥960MPa, room temperature impact energy ≥44J, hardness ≥380HB, grain size at the center and R / 2 position is 3.0±1 grade, and grain size at the edge is 4.5 grade~7.0 grade.

[0048] This invention targets difficult-to-deform high-temperature alloys such as GH4079 nickel-based superalloys, and constructs a forging process combining rapid forging and radial forging: Using rapid forging, the ingot is first held at a relatively high temperature of 1140℃~1180℃ to allow the precipitated phases in the ingot to remelt and transform into a single-phase structure, thereby improving its hot workability. Then, multiple cycles of axial upsetting are performed to break down the coarse as-cast structure. Next, one cycle of axial upsetting is performed at a forging temperature lower than the previous temperature (1140℃~1180℃) of 1120℃~1160℃ to further refine the grain structure. Finally, a single axial drawing is performed at 1120℃~1160℃ to obtain a rapidly forged billet with the required dimensions for radial forging deformation. To ensure that the surface of the rapidly forged billet is free of defects such as cracks, the billet is peeled and ground. During radial forging, a gradual heating method is adopted (550℃~600℃→880℃~920℃, 420min~480min→1120℃~1160℃, 300min~360min) to avoid the large internal and external temperature difference caused by direct high-temperature furnace entry, thus achieving temperature homogenization from the surface to the core of the billet and suppressing defects such as microcracks. In radial forging, the forging mill uses multiple hammers to synchronously and symmetrically strike the billet radially, placing it under multi-directional compressive stress, which can suppress the generation and propagation of cracks. Furthermore, the higher striking frequency and high-speed deformation of the forging mill reduce the critical deformation amount for dynamic recrystallization, making it easier to trigger recrystallization nucleation. Therefore, based on the initial improvement in microstructure uniformity achieved by rapid forging, radial forging can further obtain a more uniform fine-grained microstructure across the entire bar cross-section, resulting in an edge grain size difference of less than 3 levels for the prepared GH4079 nickel-based superalloy bar.

[0049] Example

[0050] The method for preparing GH4079 nickel-based high-temperature alloy bars based on a combination of rapid forging and radial forging in this embodiment is as follows:

[0051] (1) The chemical composition of the GH4079 alloy ingot prepared by the dual melting process of vacuum induction melting and vacuum consumable melting is shown in Table 1.

[0052] A GH4079 alloy ingot weighing 1.608t was held at 1170℃ for 240min and then forged using a high-speed forging machine. Axial upsetting was performed in two cycles, with a total deformation of 25% per cycle, to obtain an octagonal cross-section billet A.

[0053] The billet A was held at 1150℃ for 180 minutes and then subjected to one cycle of axial upsetting, with a total deformation of 30%, to obtain the octagonal cross-section billet B.

[0054] The billet B was held at 1150℃ for 180 minutes and then subjected to axial drawing in one heat, with a total deformation of 25%, to obtain the fast forging billet C.

[0055] (2) Air-cool the fast forging billet C to room temperature and perform full peeling and grinding to ensure the removal of surface defects and obtain intermediate billet D;

[0056] (3) Radial forging: The intermediate billet D is heated to 900℃ in a furnace at 600℃ and held for 420 min. Then it is heated to 1150℃ and held for 300 min. Radial forging is carried out in 4 passes using a radial forging machine. The deformation amount of the first pass is 10%, and the deformation amount of the second, third and fourth passes is 20%. Then it is air cooled to obtain GH4079 high temperature alloy bar with a diameter of 220 mm. Its edge grain size difference is <3 grade. The specific mechanical properties are shown in Table 2, and the black skin wear properties are shown in Table 3.

[0057] Comparative Example

[0058] This comparative example uses a rapid forging method for the following forging:

[0059] The GH4079 alloy ingot with a weight of 1.344t and composition as shown in Table 1 was held at 1170℃ for 240min and then forged using a high-speed forging machine. Axial upsetting was carried out in two cycles, with a total deformation of 25% per cycle, to obtain octagonal cross-section billet A.

[0060] The billet A was held at 1150℃ for 180 minutes and then axially drawn once, with a deformation of 35%, to obtain the octagonal cross-section billet B.

[0061] The billet B was held at 1150℃ for 180 min and then subjected to axial drawing in one heat treatment, with a deformation of 40%, to obtain GH4079 high-temperature alloy. The specific mechanical properties are shown in Table 2.

[0062] Table 1 Chemical composition (wt%) of GH4079 alloy ingot

[0063]

[0064] Table 2 Mechanical properties of GH4079 nickel-based superalloys prepared in the examples and comparative examples

[0065]

[0066] As shown in Table 2, the room temperature creep performance of GH4079 nickel-based superalloy bars prepared by the fast forging + radial forging cold combined method of the present invention is comparable to that of traditional fast forging process, but the room temperature tensile strength, room temperature impact and hardness are improved. Moreover, comparing the grain size of the center, 1 / 2R and edge of the two, it can be seen that the fast forging + radial forging cold combined method of the present invention effectively improves the microstructure uniformity of GH4079 nickel-based superalloy bars.

[0067] Figure 2(a) and (b) show the cross-sections of the black bar after forging in the comparative example and the embodiment, respectively. Due to its poor hot working properties, the GH4079 high-temperature alloy forged in the comparative example requires strict control of forging time to avoid cracking. During the load-bearing process, only an octagonal shape can be produced; rolling or slamming operations are not possible. This results in a shape and size consistent with the finished bar (see [reference]). Figure 2 (a) The red dotted line portion shows a significant difference. The GH4079 nickel-based high-temperature alloy bar produced by the combined fast forging and radial forging cold forging embodiments of the present invention, due to the simultaneous and symmetrical radial impact of multiple hammers from a radial forging mill after fast forging, places the billet in a multi-directional compressive stress state, which can suppress the generation and propagation of cracks. Furthermore, through the synchronous rotation of the billet, a shape and size closer to the finished bar can be obtained (see...). Figure 2 (b) The red dashed line portion).

[0068] Figure 3 (a) and (b) are cross-sectional views of the machined bright bar of GH4079 nickel-based superalloy obtained by forging in the comparative example and the embodiment, respectively. The machined bright bar of GH4079 nickel-based superalloy forged by fast forging in the comparative example, due to the sensitivity of its microstructure to deformation and temperature, is prone to uneven recrystallization at the bar edge during fast forging as the temperature decreases and the deformation becomes uneven. Figure 3 In (a), the edges show obvious banding; the GH4079 nickel-based high-temperature alloy smooth bar produced by combined fast forging and radial forging in this embodiment of the invention, due to the radial forging machine using a higher striking frequency after fast forging, the high-speed deformation reduces the critical deformation amount for dynamic recrystallization, making it easier to trigger recrystallization nucleation, effectively avoiding uneven microstructure at the edge of the bar, such as... Figure 3 (b) shows the stripless tissue at the middle edge.

[0069] Table 3. Black skin wear rate of GH4079 nickel-based superalloy bars prepared in the examples and comparative examples.

[0070]

[0071] Will Figure 2 The GH4079 nickel-based superalloy obtained by forging in the comparative example and the embodiment was machined to obtain the following results: Figure 3 The black skin wear rate of the corresponding machined bar is shown in Table 3. The GH4079 nickel-based high-temperature alloy bar produced by fast forging and radial forging combined cold forging of the present invention can significantly reduce the amount of black skin wear on the machined bar while ensuring that the uniformity of the microstructure and the comprehensive performance are not lost, thus effectively improving the yield of the product.

[0072] Those skilled in the art should recognize that the above embodiments are merely illustrative of the present invention and are not intended to limit the present invention. Any variations or modifications to the above embodiments that are within the spirit and essence of the present invention will fall within the scope of the claims of the present invention.

Claims

1. A method for preparing GH4079 nickel-based superalloy bars based on a combination of rapid forging and radial forging, characterized in that: Includes the following steps: S1, fast forging, is the process of forging GH4079 alloy ingots into fast forging billets through multiple heat treatments. S11, GH4079 alloy ingot is held at 1140℃~1180℃ for 240min~300min, and then forged by axial upsetting in multiple cycles, controlling the total deformation of a single cycle to be 20%~40%, to obtain octagonal cross-section billet A; S12, the billet A is held at 1120℃~1160℃ for 180min~240min, and axial upsetting and drawing forging is carried out in one cycle, with the total deformation controlled at 25%~35%, to obtain octagonal cross-section billet B; S13, the billet B is held at 1120℃~1160℃ for 180min~240min, and axial elongation is carried out in one cycle, with the total deformation controlled at 20%~30%, to obtain the fast forging billet; S2, after the fast forging billet is air-cooled to room temperature, it is subjected to full peeling and grinding to obtain the intermediate billet; S3, radial forging: The intermediate billet is fed into the furnace at 550℃~600℃, heated to 880℃~920℃ and held for 420min~480min, then heated to 1120℃~1160℃ and held for 300min~360min, followed by multiple passes of radial forging, controlling the total deformation to ≥50%, and air-cooled to obtain GH4079 nickel-based high-temperature alloy bars with an edge grain size difference of <3 levels.

2. The method for preparing GH4079 nickel-based high-temperature alloy bars based on the combined cold forging and radial forging according to claim 1, characterized in that: In step S11, the GH4079 alloy ingot is prepared by a dual process of vacuum induction melting and vacuum arc remelting.

3. The method for preparing GH4079 nickel-based high-temperature alloy bars based on the combined cold forging and radial forging according to claim 1, characterized in that: In step S11, the chemical composition of the GH4079 alloy ingot, by mass percentage, is as follows: carbon: 0.04%~0.08%, cobalt: 12.5%~16.0%, chromium: 10%~12%, titanium: 2.4%~3.0%, aluminum: 2.8%~3.3%, tungsten: 2.0%~3.0%, molybdenum: 4.0%~5.0%, niobium: 2.5%~3.0%, vanadium: 0.4%~0.8%, silicon ≤0.4%, iron ≤1.0%, manganese ≤0.4%, phosphorus ≤0.015%, sulfur ≤0.010%, cerium ≤0.01%, boron ≤0.01%, lanthanum ≤0.05%, neodymium ≤0.05%, magnesium ≤0.05%, lead ≤0.001%, tin ≤0.0012%, arsenic ≤0.0025%, antimony ≤0.0025%, bismuth ≤0.0001%, with the remainder being nickel.

4. The method for preparing GH4079 nickel-based high-temperature alloy bars based on the combined cold forging and radial forging according to claim 1, characterized in that: In step S11: the forging process employs at least two cycles of axial upsetting.

5. The method for preparing GH4079 nickel-based high-temperature alloy bars based on the combined cold forging and radial forging according to claim 1, characterized in that: During the rapid forging process in step S1 and the radial forging process in step S3, the surface of the billet is covered with insulating cotton during each forging.

6. The method for preparing GH4079 nickel-based high-temperature alloy bars based on the combined cold forging and radial forging according to claim 1, characterized in that: In step S3, during the radial forging, the deformation amount per pass is controlled to be 10%~20%, and the total number of passes is 3~5.

7. The method for preparing GH4079 nickel-based high-temperature alloy bars based on the combined cold forging and radial forging according to claim 1, characterized in that: In step S3, the specifications of the GH4079 nickel-based high-temperature alloy bar are Φ210mm~Φ240mm.

8. The method for preparing GH4079 nickel-based high-temperature alloy bars based on the combined cold forging and radial forging according to claim 1, characterized in that: In step S3, the GH4079 nickel-based high-temperature alloy bar has a room temperature tensile strength ≥1400MPa, a room temperature yield strength ≥960MPa, a room temperature impact energy ≥44J, a hardness ≥380HB, a grain size of 3.0±1 at the center and R / 2 position, and a grain size of 4.5 to 7.0 at the edge.

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