A nickel-based superalloy with long-term durability life and a preparation method thereof

Abstract

The present application belongs to the field of alloy material forging technology, and particularly relates to a nickel-based high-temperature alloy with long-term durable life and a preparation method thereof. The present application provides a nickel-based high-temperature alloy with long-term durable life; the nickel-based high-temperature alloy has a uniform double-grain size structure; the nickel-based high-temperature alloy is composed of the following components in the following mass percentages: C: 0.050-0.065, Cr: 19.3-20.0, Al: 1.2-1.5, Ti: 2.4-2.6, B: 0.01-0.04, Mg: 0.012-0.020, and the rest is nickel and inevitable impurities. In combination with the preparation method of the nickel-based high-temperature alloy, the nickel-based high-temperature alloy with a uniform double-grain size structure and high long-term durable life can be prepared. The long-term durable life under the condition of 650 DEG C / 300 MPa can reach 11500 h; the long-term durable life under the condition of 600 DEG C / 450 MPa can reach 10700 h. The long-term durable life under the condition of 700 DEG C / 200 MPa can reach 12400-13400 h.

Description

Technical Field

[0001] This invention belongs to the field of alloy material forging technology, specifically relating to a nickel-based superalloy with a long service life and its preparation method. Background Technology

[0002] With the further increase in temperature of advanced ultra-supercritical steam turbine units, existing 9-12Cr ferritic heat-resistant steels and Cr-Ni austenitic heat-resistant steels cannot achieve a minimum stress of 100 MPa over 1×10⁵ hours at temperatures above 700℃. When the temperature is between 700 and 760℃, nickel-based superalloys must be used for the highest-temperature components of ultra-supercritical power plant boilers and turbines. Nickel-based superalloys for ultra-supercritical steam turbine blades withstand high temperatures, complex stresses, and harsh service conditions. In addition to good high-temperature oxidation resistance, corrosion resistance, and mechanical properties, they also need good long-term structural stability and service life. The rapid development of ultra-supercritical units has led to an increasing demand for advanced high-performance alloy materials. Although nickel-based superalloy materials for ultra-supercritical steam turbine blades can be prepared in the laboratory, mass production has revealed uneven microstructure, including disordered grain size distribution and large differences in composition in different regions, ultimately resulting in poor long-term stability.

[0003] Therefore, in order to address the aforementioned technical problems and defects such as poor long-term durability and stability, there is an urgent need to design and develop a nickel-based superalloy with a long-term durability and its preparation method. Summary of the Invention

[0004] To overcome the shortcomings and difficulties of the existing technology, the first objective of this invention is to provide a nickel-based high-temperature alloy with a long service life.

[0005] The second objective of this invention is to provide a method for preparing a nickel-based superalloy with a long service life.

[0006] The first objective of this invention is achieved as follows: the nickel-based superalloy has a uniform dual-grain structure; The nickel-based superalloy is composed of the following mass percentages: C: 0.050~0.065, Cr: 19.3~20.0, Al: 1.2~1.5, Ti: 2.4~2.6, B: 0.01~0.04, Mg: 0.012~0.020, with the remainder being nickel and unavoidable impurities.

[0007] The second objective of this invention is achieved as follows: the method is applied to the nickel-based superalloy; the method includes the steps of: preheating, vacuum induction melting, ingot peeling, forging, and heat treatment; Preheating: Before vacuum induction melting, the steel ingot film is preheated at 300℃ for 12 hours, pure Cr, pure Ni, and pure Ti are held at 110℃ for 6 hours, and the vacuum induction furnace is preheated at 10kW for 3 hours. After preparation, the steel ingot film is transferred to the designated position in the vacuum induction furnace, and the raw materials are placed in the induction crucible. The induction furnace lid is closed and vacuuming is prepared. Vacuum induction melting: Evacuate to 0.1 Pa; slowly increase power to 10 kW, open the gas valve for 10 seconds after 3 minutes; continue increasing power to 20 kW, open the gas valve for 10 seconds after 3 minutes; continue increasing power to 30 kW, open the gas valve for 10 seconds after 10 minutes; slowly increase power to 50 kW, after cleaning the raw materials, slowly decrease power to 10 kW to add NiC, then decrease power to 0 kW and cool for 30 minutes; slowly increase power to 45 kW within 10 minutes, and open the Roots pump for 1 second at 35 kW to remove gas. 0s; after re-cleaning, maintain at 45kW for 1min, then slowly reduce the power to 10kW and add NiB; reduce the power to 0kW and cool for 30min; within 5min, slowly increase the power to 40kW, re-clean, and directly reduce the power to 0kW and add NiMg; after the alloy surface forms a film, gradually increase the power to 50kW and maintain for 2min within 12min, reduce to 30kW and maintain for 1min, reduce to 10kW and maintain for 1min, and then complete the casting within 25s; the ingot diameter is approximately 100~110mm; Ingot peeling: The top and bottom ends of the round ingot are cut off and the surface is machined clean by mechanical processing to remove the defect layer. The diameter of the ingot after peeling is about 80mm. Forging: At a furnace temperature of 500℃, the surface-machined ingots are placed in the furnace for homogenization annealing, with the ingots placed vertically; the furnace temperature is slowly increased to 1100~1140℃ over 4 hours and held for 16 hours; then forging is performed, with an initial forging deformation of 15~20%, followed by holding in the furnace for 1 hour; forging is performed again, with a forging deformation of 35~45%, followed by holding in the furnace for another hour; finally, final forging is performed, with a forging deformation of 85.0~86.5%; the diameter of the hot-forged round bar is approximately 30mm; Heat treatment: The round bars with a diameter of about 30 mm are subjected to the following heat treatment process: 1070℃ for 8 hours, air cooling; 845℃ for 24 hours, air cooling; 700℃ for 16 hours, air cooling.

[0008] This invention provides a nickel-based superalloy with a long creep life. The nickel-based superalloy has a uniform double-grained microstructure. The composition of the nickel-based superalloy is as follows (by mass percentage): C: 0.050~0.065, Cr: 19.3~20.0, Al: 1.2~1.5, Ti: 2.4~2.6, B: 0.01~0.04, Mg: 0.012~0.020, with the remainder being nickel and unavoidable impurities. Combined with the preparation method of the nickel-based superalloy, a nickel-based superalloy with a uniform double-grained microstructure and a long creep life can be obtained. The long-term creep life can reach 11500 h at 650℃ / 300MPa; 10700 h at 600℃ / 450MPa; and 12400-13400 h at 700℃ / 200MPa. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the metallographic microstructure of the nickel-based superalloy with long service life of the present invention. Figure 2 This is a schematic diagram of the preparation method of a nickel-based superalloy with a long service life according to the present invention. Detailed Implementation

[0010] The present invention will be further described below with reference to the accompanying drawings, but this is not intended to limit the present invention in any way. Any modifications or substitutions made based on the teachings of the present invention shall fall within the protection scope of the present invention.

[0011] As attached Figures 1-2 As shown, the present invention provides a nickel-based superalloy with a long service life. The nickel-based superalloy has a uniform double-grained microstructure; the composition of the nickel-based superalloy is as follows by mass percentage: C: 0.050~0.065, Cr: 19.3~20.0, Al: 1.2~1.5, Ti: 2.4~2.6, B: 0.01~0.04, Mg: 0.012~0.020, with the remainder being nickel and unavoidable impurities.

[0012] The nickel-based superalloy is composed of the following components by mass percentage: C: 0.061%; Cr: 19.4%; Al: 1.45%; Ti: 2.49%; B: 0.012%; Mg: 0.012%; P: <0.001%; ​​S: <0.001%; ​​Ni: balance.

[0013] The nickel-based superalloy is composed of the following components by mass percentage: C: 0.063%; Cr: 19.9%; Al: 1.26%; Ti: 2.54%; B: 0.015%; Mg: 0.018%; P: <0.001%; ​​S: <0.001%; ​​Ni: balance.

[0014] The nickel-based superalloy is composed of the following components by mass percentage: C: 0.053%; Cr: 19.5%; Al: 1.39%; Ti: 2.56%; B: 0.021%; Mg: 0.019%; P: <0.001%; ​​S: <0.001%; ​​Ni: balance.

[0015] The nickel-based superalloy is composed of the following components by mass percentage: C: 0.065%; Cr: 19.8%; Al: 1.50%; Ti: 2.55%; B: 0.032%; Mg: 0.016%; P: <0.001%; ​​S: <0.001%; ​​Ni: balance.

[0016] The present invention also provides a method for preparing a nickel-based superalloy with a long service life, the method being applied to the nickel-based superalloy; The method includes the steps of: preheating, vacuum induction melting, ingot peeling, forging, and heat treatment; Preheating: Before vacuum induction melting, the steel ingot film is preheated at 300℃ for 12 hours, pure Cr, pure Ni, and pure Ti are held at 110℃ for 6 hours, and the vacuum induction furnace is preheated at 10kW for 3 hours. After preparation, the steel ingot film is transferred to the designated position in the vacuum induction furnace, and the raw materials are placed in the induction crucible. The induction furnace lid is closed and vacuuming is prepared. Vacuum induction melting: Evacuate to 0.1 Pa; slowly increase power to 10 kW, open the gas valve for 10 seconds after 3 minutes; continue increasing power to 20 kW, open the gas valve for 10 seconds after 3 minutes; continue increasing power to 30 kW, open the gas valve for 10 seconds after 10 minutes; slowly increase power to 50 kW, after cleaning the raw materials, slowly decrease power to 10 kW to add NiC, then decrease power to 0 kW and cool for 30 minutes; slowly increase power to 45 kW within 10 minutes, and open the Roots pump for 1 second at 35 kW to remove gas. 0s; after re-cleaning, maintain at 45kW for 1min, then slowly reduce the power to 10kW and add NiB; reduce the power to 0kW and cool for 30min; within 5min, slowly increase the power to 40kW, re-clean, and directly reduce the power to 0kW and add NiMg; after the alloy surface forms a film, gradually increase the power to 50kW and maintain for 2min within 12min, reduce to 30kW and maintain for 1min, reduce to 10kW and maintain for 1min, and then complete the casting within 25s; the ingot diameter is approximately 100~110mm; Ingot peeling: The top and bottom ends of the round ingot are cut off and the surface is machined clean by mechanical processing to remove the defect layer. The diameter of the ingot after peeling is about 80mm. Forging: At a furnace temperature of 500℃, the surface-machined ingots are placed in the furnace for homogenization annealing, with the ingots placed vertically; the furnace temperature is slowly increased to 1100~1140℃ over 4 hours and held for 16 hours; then forging is performed, with an initial forging deformation of 15~20%, followed by holding in the furnace for 1 hour; forging is performed again, with a forging deformation of 35~45%, followed by holding in the furnace for another hour; finally, final forging is performed, with a forging deformation of 85.0~86.5%; the diameter of the hot-forged round bar is approximately 30mm; Heat treatment: The round bars with a diameter of about 30 mm are subjected to the following heat treatment process: 1070℃ for 8 hours, air cooling; 845℃ for 24 hours, air cooling; 700℃ for 16 hours, air cooling.

[0017] The present invention also provides a method for preparing a nickel-based superalloy with a long service life, the method being applied to the nickel-based superalloy; The method includes the steps of: preheating, vacuum induction melting, ingot peeling, forging, and heat treatment; Preheating: Before vacuum induction melting, the steel ingot film is preheated at 300℃ for 12 hours, pure Cr, pure Ni, and pure Ti are held at 110℃ for 6 hours, and the vacuum induction furnace is preheated at 10kW for 3 hours. After preparation, the steel ingot film is transferred to the designated position in the vacuum induction furnace, and the raw materials are placed in the induction crucible. The induction furnace lid is closed and vacuuming is prepared. Vacuum induction melting: Evacuate to 0.1 Pa; slowly increase power to 10 kW, open the gas valve for 10 seconds after 3 minutes; continue increasing power to 20 kW, open the gas valve for 10 seconds after 3 minutes; continue increasing power to 30 kW, open the gas valve for 10 seconds after 10 minutes; slowly increase power to 50 kW, after cleaning the raw materials, slowly decrease power to 10 kW to add NiC, then decrease power to 0 kW and cool for 30 minutes; slowly increase power to 45 kW within 10 minutes, and open the Roots pump for 1 second at 35 kW to remove gas. 0s; after re-cleaning, maintain at 45kW for 1min, then slowly reduce the power to 10kW and add NiB; reduce the power to 0kW and cool for 30min; within 5min, slowly increase the power to 40kW, re-clean, and directly reduce the power to 0kW and add NiMg; after the alloy surface forms a film, gradually increase the power to 50kW and maintain for 2min within 12min, reduce to 30kW and maintain for 1min, reduce to 10kW and maintain for 1min, and then complete the casting within 25s; the ingot diameter is approximately 100~110mm; Ingot peeling: The top and bottom ends of the round ingot are cut off and the surface is machined clean by mechanical processing to remove the defect layer. The diameter of the ingot after peeling is about 80mm. Forging: At a furnace temperature of 500℃, the surface-machined ingots are placed in the furnace for homogenization annealing, with the ingots placed vertically; the furnace temperature is slowly increased to 1120℃ over 4 hours and held for 16 hours; then forging is performed, with an initial forging deformation of 19%, followed by a furnace return and holding for 1 hour; forging is performed again, with a forging deformation of 43.8%, followed by another furnace return and holding for 1 hour; finally, a final forging is performed, with a forging deformation of 86.1%; the diameter of the hot-forged round bar is approximately 29.8 mm; Heat treatment: The round bars with a diameter of about 29.8 mm are subjected to the following heat treatment process: 1070℃ for 8 hours and air cooling; 845℃ for 24 hours and air cooling; 700℃ for 16 hours and air cooling.

[0018] The present invention also provides a method for preparing a nickel-based superalloy with a long service life, the method being applied to the nickel-based superalloy; The method includes the steps of: preheating, vacuum induction melting, ingot peeling, forging, and heat treatment; Preheating: Before vacuum induction melting, the steel ingot film is preheated at 300℃ for 12 hours, pure Cr, pure Ni, and pure Ti are held at 110℃ for 6 hours, and the vacuum induction furnace is preheated at 10kW for 3 hours. After preparation, the steel ingot film is transferred to the designated position in the vacuum induction furnace, and the raw materials are placed in the induction crucible. The induction furnace lid is closed and vacuuming is prepared. Vacuum induction melting: Evacuate to 0.1 Pa; slowly increase power to 10 kW, open the gas valve for 10 seconds after 3 minutes; continue increasing power to 20 kW, open the gas valve for 10 seconds after 3 minutes; continue increasing power to 30 kW, open the gas valve for 10 seconds after 10 minutes; slowly increase power to 50 kW, after cleaning the raw materials, slowly decrease power to 10 kW to add NiC, then decrease power to 0 kW and cool for 30 minutes; slowly increase power to 45 kW within 10 minutes, and open the Roots pump for 1 second at 35 kW to remove gas. 0s; after re-cleaning, maintain at 45kW for 1min, then slowly reduce the power to 10kW and add NiB; reduce the power to 0kW and cool for 30min; within 5min, slowly increase the power to 40kW, re-clean, and directly reduce the power to 0kW and add NiMg; after the alloy surface forms a film, gradually increase the power to 50kW and maintain for 2min within 12min, reduce to 30kW and maintain for 1min, reduce to 10kW and maintain for 1min, and then complete the casting within 25s; the ingot diameter is approximately 100~110mm; Ingot peeling: The top and bottom ends of the round ingot are cut off and the surface is machined clean by mechanical processing to remove the defect layer. The diameter of the ingot after peeling is about 80mm. Forging: At a furnace temperature of 500℃, the surface-machined ingots are placed in the furnace for homogenization annealing, with the ingots placed vertically; the furnace temperature is slowly increased to 1130℃ over 4 hours and held for 16 hours; then forging is performed, with an initial forging deformation of 16.7%, followed by a furnace return and holding for 1 hour; forging is performed again, with a forging deformation of 38%, followed by another furnace return and holding for 1 hour; finally, a final forging is performed, with a forging deformation of 85.4%; the diameter of the hot-forged round bar is approximately 30.6 mm; Heat treatment: The round bars with a diameter of about 30.6 mm are subjected to the following heat treatment process: 1070℃ for 8 hours and air cooling; 845℃ for 24 hours and air cooling; 700℃ for 16 hours and air cooling.

[0019] The present invention also provides a method for preparing a nickel-based superalloy with a long service life, the method being applied to the nickel-based superalloy; The method includes the steps of: preheating, vacuum induction melting, ingot peeling, forging, and heat treatment; Preheating: Before vacuum induction melting, the steel ingot film is preheated at 300℃ for 12 hours, pure Cr, pure Ni, and pure Ti are held at 110℃ for 6 hours, and the vacuum induction furnace is preheated at 10kW for 3 hours. After preparation, the steel ingot film is transferred to the designated position in the vacuum induction furnace, and the raw materials are placed in the induction crucible. The induction furnace lid is closed and vacuuming is prepared. Vacuum induction melting: Evacuate to 0.1 Pa; slowly increase power to 10 kW, open the gas valve for 10 seconds after 3 minutes; continue increasing power to 20 kW, open the gas valve for 10 seconds after 3 minutes; continue increasing power to 30 kW, open the gas valve for 10 seconds after 10 minutes; slowly increase power to 50 kW, after cleaning the raw materials, slowly decrease power to 10 kW to add NiC, then decrease power to 0 kW and cool for 30 minutes; slowly increase power to 45 kW within 10 minutes, and open the Roots pump for 1 second at 35 kW to remove gas. 0s; after re-cleaning, maintain at 45kW for 1min, then slowly reduce the power to 10kW and add NiB; reduce the power to 0kW and cool for 30min; within 5min, slowly increase the power to 40kW, re-clean, and directly reduce the power to 0kW and add NiMg; after the alloy surface forms a film, gradually increase the power to 50kW and maintain for 2min within 12min, reduce to 30kW and maintain for 1min, reduce to 10kW and maintain for 1min, and then complete the casting within 25s; the ingot diameter is approximately 100~110mm; Ingot peeling: The top and bottom ends of the round ingot are cut off and the surface is machined clean by mechanical processing to remove the defect layer. The diameter of the ingot after peeling is about 80mm. Forging: At a furnace temperature of 500℃, the surface-machined ingots are placed in the furnace for homogenization annealing, with the ingots placed vertically; the furnace temperature is slowly increased to 1120℃ over 4 hours and held for 16 hours; then forging is performed, with an initial forging deformation of 15.4%, followed by holding in the furnace for 1 hour; forging is performed again, with a forging deformation of 41.9%, followed by holding in the furnace for another hour; finally, final forging is performed, with a forging deformation of 85.7%; the diameter of the hot-forged round bar is approximately 30.3 mm; Heat treatment: The round bars with a diameter of about 30.3 mm are subjected to the following heat treatment process: 1070℃ for 8 hours and air cooling; 845℃ for 24 hours and air cooling; 700℃ for 16 hours and air cooling.

[0020] The present invention also provides a method for preparing a nickel-based superalloy with a long service life, the method being applied to the nickel-based superalloy; The method includes the steps of: preheating, vacuum induction melting, ingot peeling, forging, and heat treatment; Preheating: Before vacuum induction melting, the steel ingot film is preheated at 300℃ for 12 hours, pure Cr, pure Ni, and pure Ti are held at 110℃ for 6 hours, and the vacuum induction furnace is preheated at 10kW for 3 hours. After preparation, the steel ingot film is transferred to the designated position in the vacuum induction furnace, and the raw materials are placed in the induction crucible. The induction furnace lid is closed and vacuuming is prepared. Vacuum induction melting: Evacuate to 0.1 Pa; slowly increase power to 10 kW, open the gas valve for 10 seconds after 3 minutes; continue increasing power to 20 kW, open the gas valve for 10 seconds after 3 minutes; continue increasing power to 30 kW, open the gas valve for 10 seconds after 10 minutes; slowly increase power to 50 kW, after cleaning the raw materials, slowly decrease power to 10 kW to add NiC, then decrease power to 0 kW and cool for 30 minutes; slowly increase power to 45 kW within 10 minutes, and open the Roots pump for 1 second at 35 kW to remove gas. 0s; after re-cleaning, maintain at 45kW for 1min, then slowly reduce the power to 10kW and add NiB; reduce the power to 0kW and cool for 30min; within 5min, slowly increase the power to 40kW, re-clean, and directly reduce the power to 0kW and add NiMg; after the alloy surface forms a film, gradually increase the power to 50kW and maintain for 2min within 12min, reduce to 30kW and maintain for 1min, reduce to 10kW and maintain for 1min, and then complete the casting within 25s; the ingot diameter is approximately 100~110mm; Ingot peeling: The top and bottom ends of the round ingot are cut off and the surface is machined clean by mechanical processing to remove the defect layer. The diameter of the ingot after peeling is about 80mm. Forging: At a furnace temperature of 500℃, the surface-machined ingots are placed in the furnace for homogenization annealing, with the ingots placed vertically; the furnace temperature is slowly increased to 1110℃ over 4 hours and held for 16 hours; then forging is performed, with an initial forging deformation of 19.4%, followed by holding in the furnace for 1 hour; forging is performed again, with a forging deformation of 36%, followed by holding in the furnace for another hour; finally, final forging is performed, with a forging deformation of 86.2%; the diameter of the hot-forged round bar is approximately 29.7 mm; Heat treatment: The round bars with a diameter of about 29.7 mm were subjected to the following heat treatment process: 1070℃ for 8 hours and air cooling; 845℃ for 24 hours and air cooling; 700℃ for 16 hours and air cooling.

[0021] Specifically, in a specific embodiment of this solution, a method for preparing nickel-based superalloys for ultra-supercritical turbine blades that significantly improves long-term creep life is provided.

[0022] The nickel-based superalloy described is a nickel-based superalloy with a long service life of tens of thousands of hours. Its main components are composed of the following mass percentages (wt.%): C: 0.050~0.065, Cr: 19.3~20.0, Al: 1.2~1.5, Ti: 2.4~2.6, B: 0.01~0.04, Mg: 0.012~0.020, with the remainder being nickel and unavoidable impurities.

[0023] The preparation method of the aforementioned nickel-based superalloy material with a long service life of tens of thousands of hours includes: preheating → vacuum induction melting → ingot peeling → forging → heat treatment, and the specific process is shown below: Preheating: Before vacuum induction melting, the steel ingot film is preheated at 300℃ for 12 hours, pure Cr, pure Ni, and pure Ti are held at 110℃ for 6 hours, and the vacuum induction furnace is preheated at 10kW for 3 hours. Once ready, the steel ingot film should be immediately transferred to the designated position in the vacuum induction furnace, and the raw materials should be quickly placed into the induction crucible. The induction furnace lid should be closed immediately, and preparation for vacuuming should be made.

[0024] Vacuum induction melting: Evacuate to 0.1 Pa. Slowly increase the power to 10 kW, and after 3 minutes, open the gas valve to degas for 10 seconds. Continue increasing the power to 20 kW, and after 3 minutes, open the gas valve to degas for 10 seconds. Continue increasing the power to 30 kW, and after 10 minutes, open the gas valve to degas for 10 seconds. Slowly increase the power to 50 kW, and after cleaning the raw materials, slowly reduce the power to 10 kW and add NiC, then reduce the power to 0 kW and cool for 30 minutes. Within 10 minutes, slowly increase the power to 45 kW, and at 35 kW, open the Roots pump to degas for 10 seconds. After cleaning again, maintain 45 kW for 1 minute, then slowly reduce the power to 10 kW and add NiB. Reduce the power to 0 kW and cool for 30 minutes. Within 5 minutes, slowly increase the power to 40 kW, clean again, and then directly reduce the power to 0 kW and add NiMg. After the alloy surface has formed a film, the power is gradually increased to 50kW and held for 2 minutes within 12 minutes, then decreased to 30kW and held for 1 minute, then decreased to 10kW and held for 1 minute, and then the casting is completed within 25 seconds. The ingot diameter is approximately 100~110mm.

[0025] Ingot peeling: Through mechanical processing, the top and bottom ends of the round ingot are cut off and the surface is machined clean to remove the defect layer and prevent cracks from being induced in the ingot during subsequent forging. The diameter of the ingot after peeling is approximately 80mm.

[0026] Forging: At a furnace temperature of 500℃, the surface-machined ingot is placed in the furnace for homogenization annealing. To ensure more uniform heating, the ingot should be placed vertically. The furnace temperature is slowly increased to 1100~1140℃ over 4 hours and held for 16 hours. Forging is then performed, with an initial deformation of 15~20%, followed by a 1-hour holding in the furnace. Forging is performed again, with a deformation of 35~45%, followed by another 1-hour holding in the furnace. Finally, a final forging is performed, with a deformation of 85.0~86.5%. The diameter of the hot-forged bar is approximately 30mm.

[0027] Heat treatment: The round bars with a diameter of about 30 mm are subjected to the following heat treatment process: 1070℃ for 8 hours, air cooling; 845℃ for 24 hours, air cooling; 700℃ for 16 hours, air cooling.

[0028] Example 1 In this embodiment, the measured composition and mass percentage of the nickel-based superalloy material for ultra-supercritical turbine blades with a uniform dual-grain size structure are as follows: C: 0.061%; Cr: 19.4%; Al: 1.45%; Ti: 2.49%; B: 0.012%; Mg: 0.012%; P: <0.001%; ​​S: <0.001%; ​​Ni: balance; (1) Vacuum induction melting: Evacuate to 0.1 Pa. Slowly increase the power to 10 kW, and after 3 min, open the gas valve to degas for 10 s. Continue to increase the power to 20 kW, and after 3 min, open the gas valve to degas for 10 s. Continue to increase the power to 30 kW, and after 10 min, open the gas valve to degas for 10 s. Slowly increase the power to 50 kW, and after cleaning the raw materials, slowly reduce the power to 10 kW to add NiC, then reduce the power to 0 kW and cool for 30 min. Slowly increase the power to 45 kW within 10 min, and at 35 kW, open the Roots pump to degas for 10 s. After cleaning again, maintain 45 kW for 1 min, then slowly reduce the power to 10 kW to add NiB. Reduce the power to 0 kW and cool for 30 min. Slowly increase the power to 40 kW within 5 min, clean again, and then directly reduce the power to 0 kW to add NiMg. After the alloy surface has formed a film, the power is gradually increased to 50kW and held for 2 minutes within 12 minutes, then decreased to 30kW and held for 1 minute, then decreased to 10kW and held for 1 minute, and then the casting is completed within 25 seconds. The ingot diameter is approximately 100~110mm.

[0029] (2) Ingot peeling: The top and bottom ends of the round ingot are cut off and the surface is machined clean by mechanical processing to remove the defect layer and prevent the ingot from cracking during subsequent forging. The diameter of the ingot after peeling is about 80mm.

[0030] (3) Forging: At a furnace temperature of 500℃, the surface-machined ingots are placed in the furnace for homogenization annealing. To ensure more uniform heating, the ingots should be placed vertically. The furnace temperature is slowly increased to 1120℃ over 4 hours and held for 16 hours. Forging is then performed, with an initial forging deformation of 19%, followed by a 1-hour holding in the furnace. Forging is performed again, with a forging deformation of 43.8%, followed by another 1-hour holding in the furnace. Finally, a final forging is performed, with a forging deformation of 86.1%. The diameter of the hot-forged round bar is approximately 29.8 mm.

[0031] (4) Heat treatment: The round bar with a diameter of about 29.8 mm was subjected to the following heat treatment process: 1070℃ for 8 hours and air cooling; 845℃ for 24 hours and air cooling; 700℃ for 16 hours and air cooling.

[0032] The long-term tensile test sample prepared according to the above process can achieve a long-term tensile life of 11,500 hours under the conditions of 650℃ / 300MPa.

[0033] Example 2 In this embodiment, the measured composition and mass percentage of the nickel-based superalloy material for ultra-supercritical turbine blades with a uniform dual-grain size structure are as follows: C: 0.063%; Cr: 19.9%; Al: 1.26%; Ti: 2.54%; B: 0.015%; Mg: 0.018%; P: <0.001%; ​​S: <0.001%; ​​Ni: balance; (1) Vacuum induction melting: Evacuate to 0.1 Pa. Slowly increase the power to 10 kW, and after 3 min, open the gas valve to degas for 10 s. Continue to increase the power to 20 kW, and after 3 min, open the gas valve to degas for 10 s. Continue to increase the power to 30 kW, and after 10 min, open the gas valve to degas for 10 s. Slowly increase the power to 50 kW, and after cleaning the raw materials, slowly reduce the power to 10 kW to add NiC, then reduce the power to 0 kW and cool for 30 min. Slowly increase the power to 45 kW within 10 min, and at 35 kW, open the Roots pump to degas for 10 s. After cleaning again, maintain 45 kW for 1 min, then slowly reduce the power to 10 kW to add NiB. Reduce the power to 0 kW and cool for 30 min. Slowly increase the power to 40 kW within 5 min, clean again, and then directly reduce the power to 0 kW to add NiMg. After the alloy surface has formed a film, the power is gradually increased to 50kW and held for 2 minutes within 12 minutes, then decreased to 30kW and held for 1 minute, then decreased to 10kW and held for 1 minute, and then the casting is completed within 25 seconds. The ingot diameter is approximately 100~110mm.

[0034] (2) Ingot peeling: The top and bottom ends of the round ingot are cut off and the surface is machined clean by mechanical processing to remove the defect layer and prevent the ingot from cracking during subsequent forging. The diameter of the ingot after peeling is about 80mm.

[0035] (3) Forging: At a furnace temperature of 500℃, the surface-machined ingots are placed in the furnace for homogenization annealing. To ensure more uniform heating, the ingots should be placed vertically. The furnace temperature is slowly increased to 1130℃ over 4 hours and held for 16 hours. Forging is then performed, with an initial forging deformation of 16.7%, followed by a 1-hour holding in the furnace. Forging is performed again, with a forging deformation of 38.0%, followed by another 1-hour holding in the furnace. Finally, a final forging is performed, with a forging deformation of 85.4%. The diameter of the hot-forged round bar is approximately 30.6 mm.

[0036] (4) Heat treatment: The round bar with a diameter of about 30.6 mm was subjected to the following heat treatment process: 1070℃ for 8 hours and air cooling; 845℃ for 24 hours and air cooling; 700℃ for 16 hours and air cooling.

[0037] The long-term tensile test sample prepared according to the above process can achieve a long-term tensile life of 12400h under the conditions of 700℃ / 200MPa.

[0038] Example 3 In this embodiment, the measured composition and mass percentage of the nickel-based superalloy material for ultra-supercritical turbine blades with a uniform dual-grain size structure are as follows: C: 0.053%; Cr: 19.5%; Al: 1.39%; Ti: 2.56%; B: 0.021%; Mg: 0.019%; P: <0.001%; ​​S: <0.001%; ​​Ni: balance; (1) Vacuum induction melting: Evacuate to 0.1 Pa. Slowly increase the power to 10 kW, and after 3 min, open the gas valve to degas for 10 s. Continue to increase the power to 20 kW, and after 3 min, open the gas valve to degas for 10 s. Continue to increase the power to 30 kW, and after 10 min, open the gas valve to degas for 10 s. Slowly increase the power to 50 kW, and after cleaning the raw materials, slowly reduce the power to 10 kW to add NiC, then reduce the power to 0 kW and cool for 30 min. Slowly increase the power to 45 kW within 10 min, and at 35 kW, open the Roots pump to degas for 10 s. After cleaning again, maintain 45 kW for 1 min, then slowly reduce the power to 10 kW to add NiB. Reduce the power to 0 kW and cool for 30 min. Slowly increase the power to 40 kW within 5 min, clean again, and then directly reduce the power to 0 kW to add NiMg. After the alloy surface has formed a film, the power is gradually increased to 50kW and held for 2 minutes within 12 minutes, then decreased to 30kW and held for 1 minute, then decreased to 10kW and held for 1 minute, and then the casting is completed within 25 seconds. The ingot diameter is approximately 100~110mm.

[0039] (2) Ingot peeling: The top and bottom ends of the round ingot are cut off and the surface is machined clean by mechanical processing to remove the defect layer and prevent the ingot from cracking during subsequent forging. The diameter of the ingot after peeling is about 80mm.

[0040] (3) Forging: At a furnace temperature of 500℃, the surface-machined ingot is placed in the furnace for homogenization annealing. To ensure more uniform heating, the ingot should be placed vertically. The furnace temperature is slowly increased to 1120℃ over 4 hours and held for 16 hours. Forging is then performed, with an initial forging deformation of 15.4%, followed by a 1-hour holding in the furnace. Forging is performed again, with a forging deformation of 41.9%, followed by another 1-hour holding in the furnace. Finally, a final forging is performed, with a forging deformation of 85.7%. The diameter of the hot-forged round bar is approximately 30.3 mm.

[0041] (4) Heat treatment: The round bar with a diameter of about 30.3 mm was subjected to the following heat treatment process: 1070℃ for 8 hours and air cooling; 845℃ for 24 hours and air cooling; 700℃ for 16 hours and air cooling.

[0042] The long-term tensile test sample prepared according to the above process can achieve a long-term tensile life of 10,700 hours under the conditions of 600℃ / 450MPa.

[0043] Example 4 In this embodiment, the measured composition and mass percentage of the nickel-based superalloy material for ultra-supercritical turbine blades with a uniform dual-grain size structure are as follows: C0.065%; Cr: 19.8%; Al: 1.50%; Ti: 2.55%; B: 0.032%; Mg: 0.016%; P: <0.001%; ​​S: <0.001%; ​​Ni: balance; (1) Vacuum induction melting: Evacuate to 0.1 Pa. Slowly increase the power to 10 kW, and after 3 min, open the gas valve to degas for 10 s. Continue to increase the power to 20 kW, and after 3 min, open the gas valve to degas for 10 s. Continue to increase the power to 30 kW, and after 10 min, open the gas valve to degas for 10 s. Slowly increase the power to 50 kW, and after cleaning the raw materials, slowly reduce the power to 10 kW to add NiC, then reduce the power to 0 kW and cool for 30 min. Slowly increase the power to 45 kW within 10 min, and at 35 kW, open the Roots pump to degas for 10 s. After cleaning again, maintain 45 kW for 1 min, then slowly reduce the power to 10 kW to add NiB. Reduce the power to 0 kW and cool for 30 min. Slowly increase the power to 40 kW within 5 min, clean again, and then directly reduce the power to 0 kW to add NiMg. After the alloy surface has formed a film, the power is gradually increased to 50kW and held for 2 minutes within 12 minutes, then decreased to 30kW and held for 1 minute, then decreased to 10kW and held for 1 minute, and then the casting is completed within 25 seconds. The ingot diameter is approximately 100~110mm.

[0044] (2) Ingot peeling: The top and bottom ends of the round ingot are cut off and the surface is machined clean by mechanical processing to remove the defect layer and prevent the ingot from cracking during subsequent forging. The diameter of the ingot after peeling is about 80mm.

[0045] (3) Forging: At a furnace temperature of 500℃, the surface-machined ingots are placed in the furnace for homogenization annealing. To ensure more uniform heating, the ingots should be placed vertically. The furnace temperature is slowly increased to 1110℃ over 4 hours and held for 16 hours. Forging is then performed, with an initial forging deformation of 19.4%, followed by a 1-hour holding in the furnace. Forging is performed again, with a forging deformation of 36%, followed by another 1-hour holding in the furnace. Finally, a final forging is performed, with a forging deformation of 86.2%. The diameter of the hot-forged round bar is approximately 29.7 mm.

[0046] (4) Heat treatment: The round bar with a diameter of about 29.7 mm was subjected to the following heat treatment process: 1070℃ for 8 hours and air cooling; 845℃ for 24 hours and air cooling; 700℃ for 16 hours and air cooling.

[0047] The long-term tensile test sample prepared according to the above process can achieve a long-term tensile life of 13400h under the conditions of 700℃ / 200MPa.

[0048] Comparative Example 1 In this comparative example, the measured composition and mass percentage of the nickel-based superalloy material for ultra-supercritical turbine blades with a non-uniform dual-grain size microstructure are as follows: C: 0.057%; Cr: 19.3%; Al: 1.37%; Ti: 2.51%; B: 0.029%; Mg: 0.016%; P: <0.001%; ​​S: <0.001%; ​​Ni: balance; (1) Vacuum induction melting: Evacuate to 0.1 Pa. Slowly increase the power to 10 kW, and after 3 min, open the gas valve to degas for 10 s. Continue to increase the power to 20 kW, and after 3 min, open the gas valve to degas for 10 s. Continue to increase the power to 30 kW, and after 10 min, open the gas valve to degas for 10 s. Slowly increase the power to 50 kW, and after cleaning the raw materials, slowly reduce the power to 10 kW to add NiC, then reduce the power to 0 kW and cool for 30 min. Slowly increase the power to 45 kW within 10 min, and at 35 kW, open the Roots pump to degas for 10 s. After cleaning again, maintain 45 kW for 1 min, then slowly reduce the power to 10 kW to add NiB. Reduce the power to 0 kW and cool for 30 min. Slowly increase the power to 40 kW within 5 min, clean again, and then directly reduce the power to 0 kW to add NiMg. After the alloy surface has formed a film, the power is gradually increased to 50kW and held for 2 minutes within 12 minutes, then decreased to 30kW and held for 1 minute, then decreased to 10kW and held for 1 minute, and then the casting is completed within 25 seconds. The ingot diameter is approximately 100~110mm.

[0049] (2) Ingot peeling: The top and bottom ends of the round ingot are cut off and the surface is machined clean by mechanical processing to remove the defect layer and prevent the ingot from cracking during subsequent forging. The diameter of the ingot after peeling is about 80mm.

[0050] (3) Forging: At a furnace temperature of 500℃, the surface-machined ingots are placed in the furnace for homogenization annealing. To ensure more uniform heating, the ingots should be placed vertically. The furnace temperature is slowly increased to 1130℃ over 4 hours and held for 16 hours. Forging is then carried out, with a forging deformation of 23.4%. The diameter of the hot-forged round bar is approximately 70mm.

[0051] (4) Heat treatment: The round bar with a diameter of about 70 mm is subjected to the following heat treatment process: 1070℃ for 8 hours and air cooling; 845℃ for 24 hours and air cooling; 700℃ for 16 hours and air cooling.

[0052] The long-term tensile test sample prepared according to the above process has a long-term tensile life of 4500h under the conditions of 600℃ / 450MPa.

[0053] Comparative Example 2 In this comparative example, the measured composition and mass percentage of the nickel-based superalloy material for ultra-supercritical turbine blades with a non-uniform dual-grain size microstructure are as follows: C: 0.064%; Cr: 19.6%; Al: 1.23%; Ti: 2.42%; B: 0.017%; Mg: 0.014%; P: <0.001%; ​​S: <0.001%; ​​N: i balance; (1) Vacuum induction melting: Evacuate to 0.1 Pa. Slowly increase the power to 10 kW, and after 3 min, open the gas valve to degas for 10 s. Continue to increase the power to 20 kW, and after 3 min, open the gas valve to degas for 10 s. Continue to increase the power to 30 kW, and after 10 min, open the gas valve to degas for 10 s. Slowly increase the power to 50 kW, and after cleaning the raw materials, slowly reduce the power to 10 kW to add NiC, then reduce the power to 0 kW and cool for 30 min. Slowly increase the power to 45 kW within 10 min, and at 35 kW, open the Roots pump to degas for 10 s. After cleaning again, maintain 45 kW for 1 min, then slowly reduce the power to 10 kW to add NiB. Reduce the power to 0 kW and cool for 30 min. Slowly increase the power to 40 kW within 5 min, clean again, and then directly reduce the power to 0 kW to add NiMg. After the alloy surface has formed a film, the power is gradually increased to 50kW and held for 2 minutes within 12 minutes, then decreased to 30kW and held for 1 minute, then decreased to 10kW and held for 1 minute, and then the casting is completed within 25 seconds. The ingot diameter is approximately 100~110mm.

[0054] (2) Ingot peeling: The top and bottom ends of the round ingot are cut off and the surface is machined clean by mechanical processing to remove the defect layer and prevent the ingot from cracking during subsequent forging. The diameter of the ingot after peeling is about 80mm.

[0055] (3) Forging: At a furnace temperature of 500℃, the surface-machined ingots are placed in the furnace for homogenization annealing. To ensure more uniform heating, the ingots should be placed vertically. The furnace temperature is slowly increased to 1120℃ over 4 hours and held for 16 hours. Forging is then carried out, with a forging deformation of 49.2%. The diameter of the hot-forged round bar is approximately 57mm.

[0056] (4) Heat treatment: The round bar with a diameter of about 57 mm is subjected to the following heat treatment process: 1070℃ for 8 hours and air cooling; 845℃ for 24 hours and air cooling; 700℃ for 16 hours and air cooling.

[0057] The long-term tensile test sample prepared according to the above process has a long-term tensile life of 5800h under the conditions of 650℃ / 300MPa.

[0058] Comparative Example 3 In this comparative example, the measured composition and mass percentage of the nickel-based superalloy material for ultra-supercritical turbine blades with a non-uniform dual-grain size microstructure are as follows: C: 0.060%; Cr: 19.7%; Al: 1.21%; Ti: 2.47%; B: 0.024%; Mg: 0.017%; P: <0.001%; ​​S: <0.001%; ​​Ni: balance; (1) Vacuum induction melting: Evacuate to 0.1 Pa. Slowly increase the power to 10 kW, and after 3 min, open the gas valve to degas for 10 s. Continue to increase the power to 20 kW, and after 3 min, open the gas valve to degas for 10 s. Continue to increase the power to 30 kW, and after 10 min, open the gas valve to degas for 10 s. Slowly increase the power to 50 kW, and after cleaning the raw materials, slowly reduce the power to 10 kW to add NiC, then reduce the power to 0 kW and cool for 30 min. Slowly increase the power to 45 kW within 10 min, and at 35 kW, open the Roots pump to degas for 10 s. After cleaning again, maintain 45 kW for 1 min, then slowly reduce the power to 10 kW to add NiB. Reduce the power to 0 kW and cool for 30 min. Slowly increase the power to 40 kW within 5 min, clean again, and then directly reduce the power to 0 kW to add NiMg. After the alloy surface has formed a film, the power is gradually increased to 50kW and held for 2 minutes within 12 minutes, then decreased to 30kW and held for 1 minute, then decreased to 10kW and held for 1 minute, and then the casting is completed within 25 seconds. The ingot diameter is approximately 100~110mm.

[0059] (2) Ingot peeling: The top and bottom ends of the round ingot are cut off and the surface is machined clean by mechanical processing to remove the defect layer and prevent the ingot from cracking during subsequent forging. The diameter of the ingot after peeling is about 80mm.

[0060] (3) Forging: At a furnace temperature of 500℃, the surface-machined ingot is placed in the furnace for homogenization annealing. To ensure more uniform heating, the ingot should be placed vertically. The furnace temperature is slowly increased to 1135℃ over 4 hours and held for 16 hours. Forging is then performed, with an initial forging deformation of 27.8%, followed by a 1-hour holding period in the furnace. Forging is performed again, with a forging deformation of 57.8%, resulting in a hot-forged bar diameter of approximately 52 mm.

[0061] (4) Heat treatment: The round bar with a diameter of about 52 mm is subjected to the following heat treatment process: 1070℃ for 8 hours and air cooling; 845℃ for 24 hours and air cooling; 700℃ for 16 hours and air cooling.

[0062] The long-term tensile test sample prepared according to the above process has a long-term tensile life of 6400h under the conditions of 650℃ / 300MPa.

[0063] Comparative Example 4 In this comparative example, the measured composition and mass percentage of the nickel-based superalloy material for ultra-supercritical turbine blades with a non-uniform dual-grain size microstructure are as follows: C: 0.054%; Cr: 19.8%; Al: 1.36%; Ti: 2.52%; B: 0.035%; Mg: 0.017%; P: <0.001%; ​​S: <0.001%; ​​Ni: balance (1) Vacuum induction melting: Evacuate to 0.1 Pa. Slowly increase the power to 10 kW, and after 3 min, open the gas valve to degas for 10 s. Continue to increase the power to 20 kW, and after 3 min, open the gas valve to degas for 10 s. Continue to increase the power to 30 kW, and after 10 min, open the gas valve to degas for 10 s. Slowly increase the power to 50 kW, and after cleaning the raw materials, slowly reduce the power to 10 kW to add NiC, then reduce the power to 0 kW and cool for 30 min. Slowly increase the power to 45 kW within 10 min, and at 35 kW, open the Roots pump to degas for 10 s. After cleaning again, maintain 45 kW for 1 min, then slowly reduce the power to 10 kW to add NiB. Reduce the power to 0 kW and cool for 30 min. Slowly increase the power to 40 kW within 5 min, clean again, and then directly reduce the power to 0 kW to add NiMg. After the alloy surface has formed a film, the power is gradually increased to 50kW and held for 2 minutes within 12 minutes, then decreased to 30kW and held for 1 minute, then decreased to 10kW and held for 1 minute, and then the casting is completed within 25 seconds. The ingot diameter is approximately 100~110mm.

[0064] (2) Ingot peeling: The top and bottom ends of the round ingot are cut off and the surface is machined clean by mechanical processing to remove the defect layer and prevent the ingot from cracking during subsequent forging. The diameter of the ingot after peeling is about 80mm.

[0065] (3) Forging: At a furnace temperature of 500℃, the surface-machined ingots are placed in the furnace for homogenization annealing. To ensure more uniform heating, the ingots should be placed vertically. The furnace temperature is slowly increased to 1115℃ over 4 hours and held for 16 hours. Forging is then performed, with an initial forging deformation of 18.1%, followed by a 1-hour holding in the furnace. Forging is performed again, with a forging deformation of 60.9%, followed by another 1-hour holding in the furnace. Finally, a final forging is performed, with a forging deformation of 81.9%. The diameter of the hot-forged round bar is approximately 34 mm.

[0066] (4) Heat treatment: The round bar with a diameter of about 34 mm is subjected to the following heat treatment process: 1070℃ for 8 hours and air cooling; 845℃ for 24 hours and air cooling; 700℃ for 16 hours and air cooling.

[0067] The long-term tensile test sample prepared according to the above process has a long-term tensile life of 7200h under the conditions of 700℃ / 200MPa.

Claims

1. A method for preparing a nickel-based superalloy with a long service life, characterized in that, The nickel-based superalloy has a uniform bicrystalline structure; by mass percentage, the composition of the nickel-based superalloy is: C 0.050~0.065%, Cr 19.3~20.0%, Al 1.2~1.5%, Ti 2.4~2.6%, B 0.01~0.04%, Mg 0.012~0.020%, with the remainder being nickel and unavoidable impurities; the preparation method includes preheating, vacuum induction melting, ingot peeling, forging, and heat treatment steps. Preheating: Before vacuum induction melting, the steel ingot film is preheated at 300℃ for 12 hours, pure Cr, pure Ni, and pure Ti are held at 110℃ for 6 hours, and the vacuum induction furnace is preheated at 10kW for 3 hours. After preparation, the steel ingot film is transferred to the designated position in the vacuum induction furnace, and the raw materials are placed in the induction crucible. The induction furnace lid is closed and vacuuming is prepared. Vacuum induction melting: Evacuate to 0.1 Pa; slowly increase power to 10 kW, open the gas valve for 10 seconds after 3 minutes; continue increasing power to 20 kW, open the gas valve for 10 seconds after 3 minutes; continue increasing power to 30 kW, open the gas valve for 10 seconds after 10 minutes; slowly increase power to 50 kW, after cleaning the raw materials, slowly decrease power to 10 kW and add NiC, then decrease power to 0 kW and cool for 30 minutes; slowly increase power to 45 kW within 10 minutes, open the Roots pump for 10 seconds at 35 kW; after cleaning again, maintain 45 kW for 1 minute, then slowly decrease power to 10 kW and add NiB; decrease power to 0 kW and cool for 30 minutes; slowly increase power to 40 kW within 5 minutes, clean again, then directly decrease power to 0 kW and add NiMg; After the alloy surface has formed a film, the power is gradually increased to 50kW and held for 2 minutes within 12 minutes, then decreased to 30kW and held for 1 minute, then decreased to 10kW and held for 1 minute, and then the casting is completed within 25 seconds; the ingot diameter is 100~110mm. Ingot peeling: The top and bottom ends of the round ingot are cut off and the surface is machined clean by mechanical processing to remove the defect layer. The diameter of the ingot after peeling is 80mm. Forging: At a furnace temperature of 500℃, the surface-machined ingots are placed in the furnace for homogenization annealing, with the ingots placed vertically; the furnace temperature is slowly increased to 1100~1140℃ over 4 hours and held for 16 hours; then forging is performed, with an initial forging deformation of 15~20%, followed by holding in the furnace for 1 hour; forging is performed again, with a forging deformation of 35~45%, followed by holding in the furnace for another 1 hour; finally, final forging is performed, with a forging deformation of 85.0~86.5%; the diameter of the hot-forged round bar is 30mm; Heat treatment: The 30mm diameter round bar is subjected to the following heat treatment process: 1070℃ for 8 hours, air cooling; 845℃ for 24 hours, air cooling; 700℃ for 16 hours, air cooling.

2. A method for preparing a nickel-based superalloy with a long service life, characterized in that, The nickel-based superalloy has a uniform dual-grain structure; by mass percentage, the composition of the nickel-based superalloy is: C 0.061%, Cr 19.4%, Al 1.45%, Ti 2.49%, B 0.012%, Mg 0.012%, P < 0.001%, S < 0.001%, with the balance being Ni; the preparation method includes preheating, vacuum induction melting, ingot peeling, forging, and heat treatment steps. Preheating: Before vacuum induction melting, the steel ingot film is preheated at 300℃ for 12 hours, pure Cr, pure Ni, and pure Ti are held at 110℃ for 6 hours, and the vacuum induction furnace is preheated at 10kW for 3 hours. After preparation, the steel ingot film is transferred to the designated position in the vacuum induction furnace, and the raw materials are placed in the induction crucible. The induction furnace lid is closed and vacuuming is prepared. Vacuum induction melting: Evacuate to 0.1 Pa; slowly increase power to 10 kW, open the gas valve for 10 seconds after 3 minutes; continue increasing power to 20 kW, open the gas valve for 10 seconds after 3 minutes; continue increasing power to 30 kW, open the gas valve for 10 seconds after 10 minutes; slowly increase power to 50 kW, after cleaning the raw materials, slowly decrease power to 10 kW and add NiC, then decrease power to 0 kW and cool for 30 minutes; slowly increase power to 45 kW within 10 minutes, open the Roots pump for 10 seconds at 35 kW; after cleaning again, maintain 45 kW for 1 minute, then slowly decrease power to 10 kW and add NiB; decrease power to 0 kW and cool for 30 minutes; slowly increase power to 40 kW within 5 minutes, clean again, then directly decrease power to 0 kW and add NiMg; After the alloy surface has formed a film, the power is gradually increased to 50kW and held for 2 minutes within 12 minutes, then decreased to 30kW and held for 1 minute, then decreased to 10kW and held for 1 minute, and then the casting is completed within 25 seconds; the ingot diameter is 100~110mm. Ingot peeling: The top and bottom ends of the round ingot are cut off and the surface is machined clean by mechanical processing to remove the defect layer. The diameter of the ingot after peeling is 80mm. Forging: At a furnace temperature of 500℃, the surface-machined ingots are placed in the furnace for homogenization annealing, with the ingots placed vertically; the furnace temperature is slowly increased to 1120℃ over 4 hours and held for 16 hours; then forging is performed, with an initial forging deformation of 19%, followed by a furnace return and holding for 1 hour; forging is performed again, with a forging deformation of 43.8%, followed by another furnace return and holding for 1 hour; finally, a final forging is performed, with a forging deformation of 86.1%; the diameter of the hot-forged round bar is 29.8 mm; Heat treatment: The round bar with a diameter of 29.8 mm was subjected to the following heat treatment process: 1070℃ for 8 hours and air cooling; 845℃ for 24 hours and air cooling; 700℃ for 16 hours and air cooling.

3. A method for preparing a nickel-based superalloy with a long service life, characterized in that, The nickel-based superalloy has a uniform dual-grain structure; by mass percentage, the composition of the nickel-based superalloy is: C 0.063%, Cr 19.9%, Al 1.26%, Ti 2.54%, B 0.015%, Mg 0.018%, P < 0.001%, S < 0.001%, with the balance being Ni; the preparation method includes preheating, vacuum induction melting, ingot peeling, forging, and heat treatment steps. Preheating: Before vacuum induction melting, the steel ingot film is preheated at 300℃ for 12 hours, pure Cr, pure Ni, and pure Ti are held at 110℃ for 6 hours, and the vacuum induction furnace is preheated at 10kW for 3 hours. After preparation, the steel ingot film is transferred to the designated position in the vacuum induction furnace, and the raw materials are placed in the induction crucible. The induction furnace lid is closed and vacuuming is prepared. Vacuum induction melting: Evacuate to 0.1 Pa; slowly increase power to 10 kW, open the gas valve for 10 seconds after 3 minutes; continue increasing power to 20 kW, open the gas valve for 10 seconds after 3 minutes; continue increasing power to 30 kW, open the gas valve for 10 seconds after 10 minutes; slowly increase power to 50 kW, after cleaning the raw materials, slowly decrease power to 10 kW and add NiC, then decrease power to 0 kW and cool for 30 minutes; slowly increase power to 45 kW within 10 minutes, open the Roots pump for 10 seconds at 35 kW; after cleaning again, maintain 45 kW for 1 minute, then slowly decrease power to 10 kW and add NiB; decrease power to 0 kW and cool for 30 minutes; slowly increase power to 40 kW within 5 minutes, clean again, then directly decrease power to 0 kW and add NiMg; After the alloy surface has formed a film, the power is gradually increased to 50kW and held for 2 minutes within 12 minutes, then decreased to 30kW and held for 1 minute, then decreased to 10kW and held for 1 minute, and then the casting is completed within 25 seconds; the ingot diameter is 100~110mm. Ingot peeling: The top and bottom ends of the round ingot are cut off and the surface is machined clean by mechanical processing to remove the defect layer. The diameter of the ingot after peeling is 80mm. Forging: At a furnace temperature of 500℃, the surface-machined ingots are placed in the furnace for homogenization annealing, with the ingots placed vertically; the furnace temperature is slowly increased to 1130℃ over 4 hours and held for 16 hours; then forging is performed, with an initial forging deformation of 16.7%, followed by holding in the furnace for 1 hour; forging is performed again, with a forging deformation of 38%, followed by holding in the furnace for another hour; finally, final forging is performed, with a forging deformation of 85.4%; the diameter of the hot-forged round bar is 30.6 mm; Heat treatment: The round bars with a diameter of 30.6 mm were subjected to the following heat treatment process: 1070℃ for 8 hours and air cooling; 845℃ for 24 hours and air cooling; 700℃ for 16 hours and air cooling.

4. A method for preparing a nickel-based superalloy with a long service life, characterized in that, The nickel-based superalloy has a uniform dual-grain structure; by mass percentage, the composition of the nickel-based superalloy is: C 0.053%, Cr 19.5%, Al 1.39%, Ti 2.56%, B 0.021%, Mg 0.019%, P < 0.001%, S < 0.001%, with the balance being Ni; the preparation method includes preheating, vacuum induction melting, ingot peeling, forging, and heat treatment steps. Preheating: Before vacuum induction melting, the steel ingot film is preheated at 300℃ for 12 hours, pure Cr, pure Ni, and pure Ti are held at 110℃ for 6 hours, and the vacuum induction furnace is preheated at 10kW for 3 hours. After preparation, the steel ingot film is transferred to the designated position in the vacuum induction furnace, and the raw materials are placed in the induction crucible. The induction furnace lid is closed and vacuuming is prepared. Vacuum induction melting: Evacuate to 0.1 Pa; slowly increase power to 10 kW, open the gas valve for 10 seconds after 3 minutes; continue increasing power to 20 kW, open the gas valve for 10 seconds after 3 minutes; continue increasing power to 30 kW, open the gas valve for 10 seconds after 10 minutes; slowly increase power to 50 kW, after cleaning the raw materials, slowly decrease power to 10 kW and add NiC, then decrease power to 0 kW and cool for 30 minutes; slowly increase power to 45 kW within 10 minutes, open the Roots pump for 10 seconds at 35 kW; after cleaning again, maintain 45 kW for 1 minute, then slowly decrease power to 10 kW and add NiB; decrease power to 0 kW and cool for 30 minutes; slowly increase power to 40 kW within 5 minutes, clean again, then directly decrease power to 0 kW and add NiMg; After the alloy surface has formed a film, the power is gradually increased to 50kW and held for 2 minutes within 12 minutes, then decreased to 30kW and held for 1 minute, then decreased to 10kW and held for 1 minute, and then the casting is completed within 25 seconds; the ingot diameter is 100~110mm. Ingot peeling: The top and bottom ends of the round ingot are cut off and the surface is machined clean by mechanical processing to remove the defect layer. The diameter of the ingot after peeling is 80mm. Forging: At a furnace temperature of 500℃, the surface-machined ingots are placed in the furnace for homogenization annealing, with the ingots placed vertically; the furnace temperature is slowly increased to 1120℃ over 4 hours and held for 16 hours; then forging is performed, with an initial forging deformation of 15.4%, followed by holding in the furnace for 1 hour; forging is performed again, with a forging deformation of 41.9%, followed by holding in the furnace for another hour; finally, final forging is performed, with a forging deformation of 85.7%; the diameter of the hot-forged round bar is 30.3 mm; Heat treatment: The round bar with a diameter of 30.3 mm was subjected to the following heat treatment process: 1070℃ for 8 hours and air cooling; 845℃ for 24 hours and air cooling; 700℃ for 16 hours and air cooling.

5. A method for preparing a nickel-based superalloy with a long service life, characterized in that, The nickel-based superalloy has a uniform dual-grain structure; by mass percentage, the composition of the nickel-based superalloy is: C 0.065%, Cr 19.8%, Al 1.50%, Ti 2.55%, B 0.032%, Mg 0.016%, P < 0.001%, S < 0.001%, with the balance being Ni; the preparation method includes preheating, vacuum induction melting, ingot peeling, forging, and heat treatment steps. Preheating: Before vacuum induction melting, the steel ingot film is preheated at 300℃ for 12 hours, pure Cr, pure Ni, and pure Ti are held at 110℃ for 6 hours, and the vacuum induction furnace is preheated at 10kW for 3 hours. After preparation, the steel ingot film is transferred to the designated position in the vacuum induction furnace, and the raw materials are placed in the induction crucible. The induction furnace lid is closed and vacuuming is prepared. Vacuum induction melting: Evacuate to 0.1 Pa; slowly increase power to 10 kW, open the gas valve for 10 seconds after 3 minutes; continue increasing power to 20 kW, open the gas valve for 10 seconds after 3 minutes; continue increasing power to 30 kW, open the gas valve for 10 seconds after 10 minutes; slowly increase power to 50 kW, after cleaning the raw materials, slowly decrease power to 10 kW and add NiC, then decrease power to 0 kW and cool for 30 minutes; slowly increase power to 45 kW within 10 minutes, open the Roots pump for 10 seconds at 35 kW; after cleaning again, maintain 45 kW for 1 minute, then slowly decrease power to 10 kW and add NiB; decrease power to 0 kW and cool for 30 minutes; slowly increase power to 40 kW within 5 minutes, clean again, then directly decrease power to 0 kW and add NiMg; After the alloy surface has formed a film, the power is gradually increased to 50kW and held for 2 minutes within 12 minutes, then decreased to 30kW and held for 1 minute, then decreased to 10kW and held for 1 minute, and then the casting is completed within 25 seconds; the ingot diameter is 100~110mm. Ingot peeling: The top and bottom ends of the round ingot are cut off and the surface is machined clean by mechanical processing to remove the defect layer. The diameter of the ingot after peeling is 80mm. Forging: At a furnace temperature of 500℃, the surface-machined ingots are placed in the furnace for homogenization annealing, with the ingots placed vertically; the furnace temperature is slowly increased to 1110℃ over 4 hours and held for 16 hours; then forging is performed, with an initial forging deformation of 19.4%, followed by a furnace return and holding for 1 hour; forging is performed again, with a forging deformation of 36%, followed by another furnace return and holding for 1 hour; finally, a final forging is performed, with a forging deformation of 86.2%; the diameter of the hot-forged round bar is 29.7 mm; Heat treatment: The round bar with a diameter of 29.7 mm was subjected to the following heat treatment process: 1070℃ for 8 hours and air cooling; 845℃ for 24 hours and air cooling; 700℃ for 16 hours and air cooling.

6. A nickel-based superalloy with a long service life obtained by any of the preparation methods according to claims 1 to 5.

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