Forging method for improving edge structure of difficult-to-deform nickel-based superalloy bar

Abstract

The invention belongs to the technical field of high-temperature alloy hot working, and particularly discloses a forging method for improving the edge structure of a difficult-to-deform nickel-based high-temperature alloy bar, which comprises the following steps: heating and preserving heat of a difficult-to-deform nickel-based high-temperature alloy ingot, and then carrying out at least three heating times of axial upsetting and octagonal drawing to obtain a first intermediate blank; heating and heat preservation are sequentially carried out on the blank, and square drawing, diagonal drawing, secondary diagonal drawing and octagonal drawing are carried out to obtain a second intermediate blank; and finally, a target bar is obtained through heating, heat preservation, chamfering, rounding and air cooling. Wherein in the whole forging process, hot materials need to be returned to a furnace, and parameters such as temperature and deformation are strictly controlled. According to the forging method, the problem that the edge structure of the difficult-to-deform nickel-based superalloy bar is not uniform is effectively solved, the uniformity of the edge structure of the bar forged through the method is remarkably improved, then the overall performance of a forged piece is improved, and the forging method has important significance in promoting application of superalloy in the field of high-end manufacturing.

Description

Technical Field

[0001] The invention belongs to the technical field of hot processing of high-temperature alloys, and in particular relates to a forging method for improving the edge structure of a difficult-to-deform nickel-based high-temperature alloy bar. Background Art

[0002] In modern aerospace, energy and power and other high-end manufacturing fields, hard-to-deform nickel-based superalloys have become the core materials for manufacturing key hot-end components due to their excellent high-temperature strength, oxidation resistance, thermal corrosion resistance and other excellent properties. For example, the turbine blades and turbine disks of aircraft engines work under high temperature, high pressure and complex stress environments, and the performance requirements of materials are extremely stringent. Hard-to-deform nickel-based superalloys can meet the use requirements of these extreme working conditions and ensure the efficient and stable operation of the equipment.

[0003] However, when forging hard-to-deform nickel-based high-temperature alloys, the uniformity of the edge structure has always been a bottleneck restricting the development of the industry. This alloy usually contains a large amount of γ' strengthening phase and relies on MC, M6C and M 23 The synergistic strengthening of carbides such as C6 gives the alloy good strength-toughness matching characteristics, and it is mainly used in the manufacture of rotating parts of aircraft engines and gas turbines. But also because of this, the deformation resistance of difficult-to-deform nickel-based high-temperature alloys is extremely large, and its structure is extremely sensitive to hot working temperature and deformation uniformity. In actual production, the phenomenon of uneven edge structure frequently occurs. As for the free forging of difficult-to-deform nickel-based high-temperature alloys, the conventional forging method uses eight-way pulling eight-way deformation process in the forming fire. There are many factors that lead to uneven edge structure. For example, because the temperature of the hammer and anvil is much lower than the material temperature, a contact temperature drop quenching zone will be formed on the surface of the material, and the contact area between the hammer and anvil and the surface of the material is large, and the large friction will hinder the metal flow deformation in the edge area of ​​the material. This series of factors leads to the temperature and equivalent strain of the edge area of ​​the material being lower than the interior of the material when the edge area is stretched and deformed, which makes it very easy for the edge of the material to have an incompletely recrystallized mixed crystal structure. This uneven edge structure not only causes significant differences in the performance of various parts of the forging, but also during the subsequent service period, the stress concentration caused by the uneven edge structure will greatly reduce the fatigue life of the components. In severe cases, it may even cause the components to fail prematurely, posing a great threat to the safety and reliability of the equipment.

[0004] At present, it is difficult to fundamentally solve this problem with conventional forging processes. Although some processes attempt to improve the uniformity of edge structure by adjusting parameters such as heating temperature and deformation rate, these methods often fail to achieve ideal results due to the high sensitivity of difficult-to-deform nickel-based high-temperature alloys to processing technology. In addition, although some existing improved technologies can alleviate the problem of uneven edge structure to a certain extent, they are often accompanied by disadvantages such as reduced production efficiency and significantly increased costs, which makes it difficult to meet the actual needs of industrial large-scale production. Therefore, it is urgent to develop a forging method that can effectively improve the uniformity of edge structure of difficult-to-deform nickel-based high-temperature alloys while having the advantages of high efficiency and low cost.

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

[0006] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a forging method for improving the edge structure of difficult-to-deform nickel-based high-temperature alloy bars. It is mainly used to solve the problem that the traditional process for preparing difficult-to-deform nickel-based high-temperature alloy bars is prone to incomplete recrystallization of mixed crystal structures, thereby achieving the purpose of improving the uniformity of the edge structure, thereby improving the overall performance of the forging and meeting the needs of industrial large-scale production.

[0007] The purpose of the present invention is to be solved by the following technical solutions:

[0008] A forging method for improving the edge structure of a difficult-to-deform nickel-based high-temperature alloy bar, the forging method comprising the following steps:

[0009] Step 1, heating a hard-to-deform nickel-based high-temperature alloy ingot to a set temperature and then keeping the temperature, and after the ingot is heated through, performing at least three times of axial upsetting and octagonal stretching operations on the hard-to-deform nickel-based high-temperature alloy ingot to obtain a first intermediate billet with an octagonal cross section;

[0010] Step 2, heating the first intermediate blank to a set temperature and then keeping the temperature, and after the temperature is completely heated, performing a heat treatment on the first intermediate blank to obtain a first square blank;

[0011] Step 3, heating the first square blank to a set temperature and then keeping the temperature, and after the temperature is completely heated, performing a diagonal stretching on the first square blank to obtain a second square blank;

[0012] Step 4, after heating the second square blank to a set temperature and keeping it warm for a set time, the second square blank is subjected to a first-time diagonal stretching and octagonal stretching to obtain a second intermediate blank with an octagonal cross section;

[0013] Step 5, heating the second intermediate billet to a set temperature and then keeping it warm, performing a rounding process on the second intermediate billet with the same specifications after it is heated through, and air cooling it to room temperature to obtain the target difficult-to-deform nickel-based high-temperature alloy rod.

[0014] Furthermore, in step 1, the difficult-to-deform nickel-based high-temperature alloy ingot is obtained by a double melting process of vacuum induction melting + vacuum consumable melting, or by a triple melting process of vacuum induction melting + electroslag remelting + vacuum consumable melting.

[0015] Furthermore, in step 1, the Al+Ti element content in the difficult-to-deform nickel-based high-temperature alloy ingot is 4.0% to 5.5%, the Co element content is 12.0% to 16.0%, and the Mo element content is 3.0% to 6.0%.

[0016] Furthermore, in step 1, the difficult-to-deform nickel-based high-temperature alloy ingot is heated to 80°C to 120°C above the dissolution temperature of the γ' strengthening phase, and the deformation amount of each fire during the axial upsetting and octagonal drawing is 15% to 30%. Preferably, the deformation amount of each fire during the axial upsetting and octagonal drawing is 17% to 28%, and the surface of the material needs to be coated with thermal insulation asbestos before each deformation.

[0017] Furthermore, in step 2, the first intermediate blank is heated to 40°C to 80°C above the dissolution temperature of the γ' strengthening phase, the deformation during the four-way drawing is 25% to 40%, preferably, the deformation during the four-way drawing is 26% to 38%, and the surface of the material needs to be coated with thermal insulation asbestos before each deformation.

[0018] Furthermore, in step 3, the first square blank is heated to 10°C to 40°C above the dissolution temperature of the γ' strengthening phase, and the deformation during the diagonal drawing is 35% to 50%. Preferably, the deformation during the diagonal drawing is 35% to 47%, and the surface of the material needs to be coated with thermal insulation asbestos before each deformation.

[0019] Further, in step 4, the second square billet is heated to 10°C to 40°C above the dissolution temperature of the γ' strengthening phase and then kept warm, and the holding time is set to (0.1 to 0.2) Dmin, and the deformation during the diagonal stretching + eight-way stretching is 35% to 50%, preferably, the deformation during the diagonal stretching + eight-way stretching is 36% to 47%, and the surface of the material needs to be coated with thermal insulation asbestos before each deformation;

[0020] Wherein, D is the side length of the second square blank, in mm.

[0021] Furthermore, in step 5, the second intermediate blank is heated to a temperature 10° C. to 40° C. below the dissolution temperature of the γ' strengthening phase.

[0022] Furthermore, the first intermediate blank, the first square blank, the second square blank and the second intermediate blank all need to be hot-melted.

[0023] Furthermore, the forging method is used to produce hard-to-deform nickel-based high-temperature alloy rods with a specification of Φ150mm to Φ300mm, and the edge structure of the hard-to-deform nickel-based high-temperature alloy rods is uniform.

[0024] Preferably, the forging method is used to produce difficult-to-deform nickel-based high-temperature alloy bars with a specification of Φ180mm to Φ280mm.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The forging method provided by the present invention greatly reduces the contact area between the material surface and the hammer anvil by using the square billet edge and the hammer anvil for deformation, which not only reduces the contact temperature drop between the edge and the hammer anvil to increase the edge drawing deformation temperature, but also reduces the friction force, effectively increases the metal flow deformation in the edge area, thereby significantly improving the temperature and equivalent strain of the edge area of ​​the material during the drawing deformation. At the same time, the short-term heat preservation between the two diagonal drawing fires avoids the excessive coarsening of the recrystallized structure refined after the first fire diagonal drawing during reheating, and provides a uniform and refined billet structure for the subsequent forming diagonal drawing fire. These unique designs make this forging method effective in improving the uniformity of the edge structure of difficult-to-deform nickel-based high-temperature alloy bars, effectively avoiding incomplete recrystallization of mixed crystal structures, and improving the overall performance of forgings. In addition, the forging method has a clear operating process and clear process parameters. While ensuring high efficiency, it controls costs and meets the needs of industrial large-scale production. It is particularly suitable for the production of difficult-to-deform nickel-based high-temperature alloy bars with specifications of Φ150mm~Φ300mm, especially Φ180mm~Φ280mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings are incorporated in and constitute a part of this specification and, together with the description, serve to explain the principles of the present invention.

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0029] Figure 1 This is a flow chart of the forging method for improving the edge structure of a difficult-to-deform nickel-based high-temperature alloy bar of the present invention;

[0030] Figure 2 This is the microstructure diagram of the Φ280mm bar at 0mm from the edge prepared by conventional forging method;

[0031] Figure 3 This is the microstructure diagram of the Φ280mm bar 5mm away from the edge prepared by conventional forging method;

[0032] Figure 4 The microstructure diagram of the Φ280mm bar at 0mm from the edge prepared by the forging method of the present invention;

[0033] Figure 5 The microstructure diagram of a Φ280 mm bar at a distance of 5 mm from the edge is prepared by the forging method of the present invention. DETAILED DESCRIPTION

[0034] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are merely examples of devices consistent with some aspects of the present invention as detailed in the appended claims.

[0035] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0036] See also Figure 1 , the present invention provides a forging method for improving the edge structure of a difficult-to-deform nickel-based high-temperature alloy bar, which specifically includes the following steps;

[0037] Step 1, heating a hard-to-deform nickel-based high-temperature alloy ingot to a temperature 80°C to 120°C above the γ' strengthening phase re-dissolution temperature and then keeping the temperature, and after the ingot is heated through, performing at least three times of axial upsetting and octagonal drawing operations on the hard-to-deform nickel-based high-temperature alloy ingot, and the deformation amount of each time is 15% to 30%, to obtain a first intermediate billet with an octagonal cross-section, and returning the hot material to the furnace after forging;

[0038] Step 2, heating the first intermediate billet to 40°C to 80°C above the dissolution temperature of the γ' strengthening phase and then keeping the temperature, and after the first intermediate billet is heated through, performing a first-fire square drawing to control the deformation amount to 25% to 40% to obtain a first square billet, and then slightly chamfering the edges of the first square billet, and returning the hot material after forging to the furnace;

[0039] Step 3, heating the first square billet to 10°C to 40°C above the γ' strengthening phase re-dissolution temperature and then keeping the temperature, and after the first square billet is heated through, performing a diagonal stretching on the first square billet (i.e., only pressing and deforming the edges of the first square billet to obtain a second square billet that is approximately rotated 45° compared to the square billet 1), controlling the deformation amount to 35% to 50%, and obtaining a second square billet, and then slightly chamfering the edges of the second square billet, and returning the hot material to the furnace after forging;

[0040] Step 4, heating the second square billet to 10°C to 40°C above the γ' strengthening phase re-dissolution temperature and then keeping the temperature, and setting the holding time to (0.1 to 0.2)D (D is the side length of the second square billet) min, and then performing a fire diagonal stretching + octagonal stretching on the second square billet (i.e., firstly pressing down and deforming the edges of the second square billet to form an approximate third square billet rotated 45° compared with the second square billet, and then continuing to press down and deform the edges of the third square billet, i.e., the original plane of the original second square billet), controlling the deformation amount to 35% to 50%, and obtaining a second intermediate billet with an octagonal cross section, and returning the hot material to the furnace after forging;

[0041] Step 5, heating the second intermediate billet to 10°C to 40°C below the γ' strengthening phase re-dissolution temperature and then keeping the temperature, performing a rounding operation on the second intermediate billet with the same specifications after the billet is heated through, and air cooling the billet to room temperature to obtain the target difficult-to-deform nickel-based high-temperature alloy rod.

[0042] Among them, in step 1, the difficult-to-deform nickel-based high-temperature alloy ingot is obtained by a double melting process of vacuum induction melting + vacuum consumable melting, or by a triple melting process of vacuum induction melting + electroslag remelting + vacuum consumable melting, and the Al+Ti element content of the difficult-to-deform nickel-based high-temperature alloy ingot is 4.0% to 5.5%, the Co element content is 12.0% to 16.0%, and the Mo element content is 3.0% to 6.0%. At the same time, in steps 1 to 4, the surface of the material needs to be coated with thermal insulation asbestos before each fire deformation.

[0043] In order to further verify the efficacy of the forging method of the present invention, the inventors conducted the following specific examples (Note: the γ' strengthening phase resolubility temperature of the hard-to-deform nickel-based high-temperature alloy ingot in the embodiment of the present invention is about 1050°C):

[0044] Example 1 (Preparation of Φ280 mm difficult-to-deform nickel-based high-temperature alloy rod)

[0045] This embodiment is used to prepare a hard-to-deform nickel-based high-temperature alloy bar with a specification of Φ280 mm, and the forging process is as follows:

[0046] 1) The hard-to-deform nickel-based high-temperature alloy ingot was heated to 1170°C and kept warm for 5 hours, and then the hard-to-deform nickel-based high-temperature alloy ingot was subjected to five times of axial upsetting and octagonal drawing operations, and the deformation amount of each fire was 28%, to obtain a first intermediate billet with an octagonal cross-section (side length of 670 mm), and the hot material was returned to the furnace after forging.

[0047] 2) The first intermediate blank obtained in step 1) is heated to 1130° C. and then kept warm for 3 hours, and then the first intermediate blank is subjected to a first heat and square drawing, and the deformation amount is controlled to be 38% to obtain a first square blank with a side length of 480 mm, and then the edges of the first square blank are slightly chamfered, and the hot material after forging is returned to the furnace;

[0048] 3) The first square blank obtained in step 2) is heated to 1090°C and then kept warm for 2.5 hours, and then the first square blank is subjected to a first-time diagonal stretching, that is, only the edges of the first square blank are pressed down and deformed to obtain a second square blank that is approximately rotated 45° compared to the first square blank, and the deformation amount is controlled to be 47% to obtain a second square blank with a side length of 350 mm, and then the edges of the second square blank are slightly chamfered, and the hot material is returned to the furnace after forging;

[0049] 4) After heating the second square billet obtained in step 3) to 1090°C and keeping it warm for 60 minutes, the second square billet is subjected to a first-time diagonal stretching + octagonal stretching, that is, the edge of the second square billet with a side length of 350 mm is first pressed down to form an approximate third square billet (with a side length of 270 mm) rotated 45° compared with the second square billet, and then the edge of the third square billet, that is, the original plane of the original second square billet, is pressed down to deform, and the deformation amount is controlled to be 47% to obtain a second intermediate billet with an octagonal cross section (with a side length of 280 mm), and the hot material is returned to the furnace after forging;

[0050] 5) The second intermediate billet obtained in step 4) is heated to 1040° C. and then kept at this temperature for 2 hours. The second intermediate billet is then subjected to a rounding process with the same specifications and air-cooled to room temperature to obtain a target difficult-to-deform nickel-based high-temperature alloy bar with a specification of Φ280 mm.

[0051] The microstructure of the Φ280mm hard-to-deform nickel-based high-temperature alloy rod at 0mm from the edge prepared in the embodiment of the present invention is as follows Figure 4 As shown, the structure 5 mm away from the edge is as follows Figure 5 At the same time, the inventors used conventional forging methods to prepare the same specification of Φ280mm hard-to-deform nickel-based high-temperature alloy bars as a comparative example. It can be clearly seen that the existing forging process has a poor recrystallization degree at 0mm from the edge. The stretched necklace structure (such as Figure 2 As shown in the figure), there are still some large grains that are not completely recrystallized 5mm away from the edge (as shown in the figure). Figure 3As shown in the figure). However, in the forging process of the present invention, some large grains that are not completely recrystallized remain at 0 mm from the edge, and a uniform structure of complete recrystallization can be obtained at 5 mm from the edge. Compared with the existing forging process, the uniformity of the edge structure can be greatly improved.

[0052] Example 2 (Preparation of Φ240 mm difficult-to-deform nickel-based high-temperature alloy rod)

[0053] This embodiment is used to prepare a hard-to-deform nickel-based high-temperature alloy bar with a specification of Φ240 mm, and the forging process is as follows:

[0054] 1) The hard-to-deform nickel-based high-temperature alloy ingot was heated to 1150° C. and kept warm for 5 hours. The hard-to-deform nickel-based high-temperature alloy ingot was then subjected to five rounds of axial upsetting and octagonal drawing operations, and the deformation amount of each round was 23%, to obtain a first intermediate billet with an octagonal cross-section (side length of 520 mm), and the hot material was returned to the furnace after forging.

[0055] 2) The first intermediate blank obtained in step 1) is heated to 1110° C. and then kept warm for 2.5 hours, and then the first intermediate blank is subjected to a first heat and square drawing, and the deformation amount is controlled to be 34%, so as to obtain a first square blank with a side length of 385 mm, and then the edges of the first square blank are slightly chamfered, and the hot material after forging is returned to the furnace;

[0056] 3) The first square blank obtained in step 2) is heated to 1080°C and then kept warm for 2h, and then the first square blank is subjected to a diagonal stretching, that is, only the edges of the first square blank are pressed down to obtain a second square blank that is approximately rotated 45° compared to the first square blank, and the deformation amount is controlled to be 43% to obtain a second square blank with a side length of 290mm, and then the edges of the second square blank are slightly chamfered, and the hot material is returned to the furnace after forging;

[0057] 4) The second square billet obtained in step 3) is heated to 1080°C and then kept warm for 50 minutes, and then the second square billet is subjected to a first-time diagonal stretching + octagonal stretching, that is, the edge of the second square billet with a side length of 290 mm is first pressed down to form an approximate third square billet (with a side length of 230 mm) rotated 45° compared with the second square billet, and then the edge of the third square billet, that is, the original plane of the original second square billet, is pressed down to deform, and the deformation amount is controlled to be 43% to obtain a second intermediate billet with an octagonal (side length of 240 mm) cross section, and the hot material is returned to the furnace after forging;

[0058] 5) The second intermediate billet obtained in step 4) is heated to 1030° C. and then kept warm for 1.5 hours. The second intermediate billet is then subjected to a rounding process with the same specifications and air-cooled to room temperature to obtain a target difficult-to-deform nickel-based high-temperature alloy bar with a specification of Φ240 mm.

[0059] Example 3 (Preparation of Φ180 mm difficult-to-deform nickel-based high-temperature alloy rod)

[0060] This embodiment is used to prepare a hard-to-deform nickel-based high-temperature alloy bar with a specification of Φ180 mm, and the forging process is as follows:

[0061] 1) The hard-to-deform nickel-based high-temperature alloy ingot was heated to 1130°C and kept warm for 5 hours, and then the hard-to-deform nickel-based high-temperature alloy ingot was subjected to five times of axial upsetting and octagonal drawing operations, and the deformation amount of each fire was 17%, to obtain a first intermediate billet with an octagonal cross-section (side length of 325 mm), and the hot material was returned to the furnace after forging.

[0062] 2) The first intermediate blank obtained in step 1) is heated to 1090° C. and then kept at this temperature for 2 hours, and then the first intermediate blank is subjected to a first heat and square drawing, and the deformation amount is controlled to be 26%, so as to obtain a first square blank with a side length of 255 mm, and then the edges of the first square blank are slightly chamfered, and the hot material after forging is returned to the furnace;

[0063] 3) The first square blank obtained in step 2) is heated to 1060°C and then kept warm for 1.5 hours, and then the first square blank is subjected to a first-time diagonal stretching, that is, only the edges of the first square blank are pressed down and deformed to obtain a second square blank that is approximately rotated 45° compared to the first square blank, and the deformation amount is controlled to be 35% to obtain a second square blank with a side length of 205 mm, and then the edges of the second square blank are slightly chamfered, and the hot material is returned to the furnace after forging;

[0064] 4) The second square billet obtained in step 3) is heated to 1060°C and then kept warm for 30 minutes, and then the second square billet is subjected to a first-time diagonal stretching + octagonal stretching, that is, the edge of the second square billet with a side length of 205 mm is first pressed down to form an approximate third square billet (with a side length of 170 mm) rotated 45° compared with the second square billet, and then the edge of the third square billet, that is, the original plane of the original second square billet, is pressed down to deform, and the deformation amount is controlled to be 36%, to obtain a second intermediate billet with an octagonal cross section (with a side length of 180 mm), and the hot material is returned to the furnace after forging;

[0065] 5) The second intermediate billet obtained in step 4) is heated to 1010° C. and then kept warm for 1 hour. The second intermediate billet is then subjected to a rounding process with the same specifications and air-cooled to room temperature to obtain a target difficult-to-deform nickel-based high-temperature alloy bar with a specification of Φ180 mm.

[0066] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention.

[0067] It should be understood that the present invention is not limited to what has been described above and that various modifications and changes may be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A forging method for improving the edge structure of a difficult-to-deform nickel-based high-temperature alloy bar, characterized in that: The forging method The steps include: Step 1, heating a hard-to-deform nickel-based high-temperature alloy ingot to a set temperature and then keeping the temperature, and after the ingot is heated through, performing at least three times of axial upsetting and octagonal stretching operations on the hard-to-deform nickel-based high-temperature alloy ingot to obtain a first intermediate billet with an octagonal cross section; Step 2, heating the first intermediate blank to a set temperature and then keeping the temperature, and after the temperature is completely heated, performing a heat treatment on the first intermediate blank to obtain a first square blank; Step 3, heating the first square blank to a set temperature and then keeping the temperature, and after the temperature is completely heated, performing a diagonal stretching on the first square blank to obtain a second square blank; Step 4, after heating the second square blank to a set temperature and keeping it warm for a set time, the second square blank is subjected to a first-time diagonal stretching and octagonal stretching to obtain a second intermediate blank with an octagonal cross section; Step 5, heating the second intermediate billet to a set temperature and then keeping it warm, performing a rounding process on the second intermediate billet with the same specifications after it is heated through, and air cooling it to room temperature to obtain the target difficult-to-deform nickel-based high-temperature alloy rod.

2. The forging method for improving the edge structure of a difficult-to-deform nickel-based high-temperature alloy bar according to claim 1, characterized in that: In step 1, the hard-to-deform nickel-based high-temperature alloy ingot is obtained by a double melting process of vacuum induction melting + vacuum consumable melting, or by a triple melting process of vacuum induction melting + electroslag remelting + vacuum consumable melting.

3. The forging method for improving the edge structure of a difficult-to-deform nickel-based high-temperature alloy bar according to claim 1, characterized in that: In step 1, the Al+Ti element content in the hard-to-deform nickel-based high-temperature alloy ingot is 4.0% to 5.5%, the Co element content is 12.0% to 16.0%, and the Mo element content is 3.0% to 6.0%.

4. The forging method for improving the edge structure of a difficult-to-deform nickel-based high-temperature alloy bar according to claim 1, characterized in that: In step 1, the hard-to-deform nickel-based high-temperature alloy ingot is heated to 80°C to 120°C above the dissolution temperature of the γ' strengthening phase, the deformation amount of each fire during the axial upsetting and 8-way drawing is 15% to 30%, and the surface of the material needs to be coated with thermal insulation asbestos before each fire deformation.

5. The forging method for improving the edge structure of a difficult-to-deform nickel-based high-temperature alloy bar according to claim 1, characterized in that: In step 2, the first intermediate blank is heated to 40°C to 80°C above the dissolution temperature of the γ' strengthening phase, the deformation amount during the four-way drawing is 25% to 40%, and the surface of the material needs to be coated with thermal insulation asbestos before each deformation.

6. The forging method for improving the edge structure of a difficult-to-deform nickel-based high-temperature alloy bar according to claim 1, characterized in that: In step 3, the first square blank is heated to 10°C to 40°C above the dissolution temperature of the γ' strengthening phase, the deformation during the diagonal stretching is 35% to 50%, and the surface of the material needs to be coated with thermal insulation asbestos before each deformation.

7. The forging method for improving the edge structure of a difficult-to-deform nickel-based high-temperature alloy bar according to claim 1, characterized in that: In step 4, the second square blank is heated to 10°C to 40°C above the re-dissolution temperature of the γ' strengthening phase and then kept warm, and the holding time is set to (0.1 to 0.2) Dmin, the deformation amount during the diagonal stretching + octagonal stretching is 35% to 50%, and the surface of the material needs to be coated with thermal insulation asbestos before each deformation; Wherein, D is the side length of the second square blank, in mm.

8. The forging method for improving the edge structure of a difficult-to-deform nickel-based high-temperature alloy bar according to claim 1, characterized in that: In step 5, the second intermediate blank is heated to 10° C. to 40° C. below the dissolution temperature of the γ' strengthening phase.

9. The forging method for improving the edge structure of a difficult-to-deform nickel-based high-temperature alloy bar according to claim 1, characterized in that: The first intermediate blank, the first square blank, the second square blank and the second intermediate blank all need to be returned to the furnace as hot materials.

10. The forging method for improving the edge structure of a difficult-to-deform nickel-based high-temperature alloy bar according to any one of claims 1 to 9, characterized in that: The forging method is used to produce hard-to-deform nickel-based high-temperature alloy bars with a specification of Φ150mm to Φ300mm, and the edge structure of the hard-to-deform nickel-based high-temperature alloy bars is uniform.

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