High-strength high-temperature alloy and preparation method thereof

Abstract

The invention discloses a high-strength high-temperature alloy and a preparation method thereof. The high-strength high-temperature alloy comprises a high-temperature alloy matrix and rare earth oxides dispersed and distributed in the high-temperature alloy matrix. The high-temperature alloy matrix is GH4169, and the high-temperature alloy matrix is made of The rare earth oxide is one or two of La2O3 and Ce2O3, the particle size of the rare earth oxide is 50-500nm, and the total adding amount of the rare earth oxide is 0.02-0.03% of the mass of the alloy; the preparation method of the high-strength high-temperature alloy comprises the following steps: (1) preparing rare earth oxide particles; (2) charging and smelting rare earth oxide particles and alloy raw materials in a vacuum induction furnace, and casting into ingots after the components are qualified; (3) electroslag remelting: adding analytically pure rare earth oxide into a slag system; and (4) the electroslag ingot is subjected to homogenization, forging and solid solution aging treatment, and then the alloy is obtained. According to the method, the strength and plasticity of the high-temperature alloy are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal materials, and in particular relates to a high-strength high-temperature alloy and a preparation method thereof. Background Art

[0002] High-temperature alloy refers to a type of metal material with nickel, iron, and cobalt as the matrix, with the addition of one or more alloying elements such as chromium, molybdenum, niobium, tungsten, aluminum, and titanium. It can serve for a long time under high temperatures above 600°C and specific stress conditions. It has excellent high-temperature strength, good oxidation resistance and thermal corrosion resistance, good fatigue and durability, and is widely used in aerospace, nuclear power, chemical industry, energy and other fields.

[0003] Among all high-temperature alloy categories, GH4169 is the most widely used. It has excellent comprehensive properties at -253℃ to 650℃ and is used to manufacture aircraft engine blades, turbine disks, compressor blades, valves, pipes, connectors in oil wells, natural gas wells and petrochemical equipment, as well as structural parts and containers in nuclear reactors.

[0004] Currently, the GH4169 smelting process typically involves a dual vacuum induction melting and electroslag remelting process. The quality of the ingot directly impacts its subsequent performance. Laves phase often appears in GH4169 ingots produced using traditional processes, significantly detrimental to strength and toughness. The primary cause of Laves phase is Nb segregation. During alloy solidification, the chemical differences between Nb and the Ni matrix result in the formation of a Nb-rich γ+Laves eutectic structure between the dendrites. Generally, the coarser the dendrites, the more severe the Laves phase precipitation. Therefore, the most effective way to reduce or resolve Laves phase during smelting is to control the solidification process to achieve a uniform, fine solidification structure.

[0005] Studies have shown that adding fine, high-melting-point oxides or nitrides to steel can effectively inhibit grain growth, achieve uniform solidification, and increase material strength. Oxide metallurgy, invented in Japan in the 1970s, involves adding fine particles such as TiN and Ti2O3 to steel to improve the material structure and enhance HAZ toughness. This technology is currently widely used in industry.

[0006] However, there are no reports on the addition of fine particles to high-temperature alloys. The matrix elements of high-temperature alloys, Ni, Co, and Fe, are all Group VIII elements with very similar properties and are infinitely miscible. In theory, the addition of fine particles to high-temperature alloys can also play a positive role. Summary of the Invention

[0007] The present invention aims to provide a high-strength high-temperature alloy and a preparation method thereof. During vacuum induction melting of GH4169, prepared rare earth oxide particles are added to the furnace. By controlling the distribution and melting system, the rare earth oxides are evenly dispersed into the alloy matrix. Then, through electroslag remelting using a rare earth oxide-containing slag system, the fine and dispersed rare earth oxide particles become the crystallization cores of the matrix phase, thereby increasing the phase deformation nucleation rate, refining and uniformizing the solidification structure, reducing the precipitation of brittle Laves phase, and improving the strength and plasticity of GH4169.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is:

[0009] A high-strength high-temperature alloy comprises a high-temperature alloy matrix and rare earth oxides dispersed in the high-temperature alloy matrix; the high-temperature alloy matrix is ​​GH4169; the rare earth oxides are one or both of La2O3 and Ce2O3, with a particle size of 50 to 500 nm and a total amount of 0.02 to 0.03% of the alloy mass.

[0010] The preparation method of the high-strength high-temperature alloy of the present invention is as follows:

[0011] (1) preparing rare earth oxide particles;

[0012] (2) Vacuum induction melting: 30% to 40% of the total amount of rare earth oxide particles are evenly spread on the bottom of the crucible, and then alloy material is spread on it to 1 / 3 to 1 / 2 of the height of the crucible, and then 30% to 40% of the total amount of rare earth oxide particles are evenly sprinkled in, and then alloy material is spread to 2 / 3 to 3 / 4 of the height of the crucible, and the remaining amount of rare earth oxide particles are evenly sprinkled in, and finally alloy material is spread to the furnace mouth; after the materials are laid, the furnace is closed, vacuum melting is carried out, and after the composition is qualified, it is cast into a consumable electrode;

[0013] (3) electroslag remelting: The electroslag smelting process is protected by argon gas throughout, and 0.5-1.5% of the analytically pure rare earth oxide in the rare earth oxide particles in step (1) is added to the slag system to obtain an electroslag ingot;

[0014] (4) The electroslag ingot is subjected to homogenization, forging, and solid solution aging treatment in sequence to obtain the finished product.

[0015] Furthermore, in the method for preparing the high-strength high-temperature alloy of the present invention, the method for preparing the rare earth oxide particles in step (1) is as follows:

[0016] Analytical pure rare earth oxides La2O3, Ce2O3 and nickel powder were mechanically ground to 50-500 nm respectively;

[0017] Mix the rare earth oxide and nickel powder in a mass ratio of (0.2-0.3):1;

[0018] The mixed material is isostatically sintered at 1260-1300°C, a pressure of 150-180 MPa, and a sintering time of 5-5.5 h;

[0019] The sintered block material is crushed into particles of 3 to 5 mm in size.

[0020] Furthermore, the analytically pure rare earth oxides La2O3, Ce2O3 and nickel powder of the present invention are ground to 50-500 nm using a ball mill. During the grinding process, the ball-to-material ratio is (8-9):1, the rotation speed is 450-500 r / min, argon protection is used, and the ball milling time is 3-3.5 h.

[0021] Furthermore, the rare earth oxide and nickel powder of the present invention are uniformly mixed in a ball mill with a ball-to-material ratio of (8-9):1, a rotation speed of 200-250 r / min, argon protection, and a mixing time of 1.5-2 h.

[0022] The beneficial effects of adopting the above technical solution are:

[0023] (1) More comprehensive considerations are given to process design. Rare earth oxides have a high density, close to the density of nickel liquid. Due to their high melting point, they always remain solid particles in nickel liquid. In addition, their small particle size allows them to perform Brownian motion in nickel liquid and will not float up. Instead, they will be evenly distributed in the nickel liquid. The densities of La2O3 and Ce2O3 used in the present invention are 6.51 g / cm 3 and 6.2g / cm 3 , close to the density of liquid nickel 7.2g / cm 3 The melting points of La2O3 and Ce2O3 are 2315℃ and 2210℃, which are much higher than the smelting temperature of 1550℃~1650℃. Therefore, La2O3 and Ce2O3 can maintain solid phase in nickel liquid. -7 ~10 -5 m, the rare earth oxide particles used in the present invention are 50 to 500 nm, i.e. (0.5 to 5)*10 -7 m, is in the Brownian motion size range. Therefore, the process of the present invention can achieve the dispersion and distribution of rare earth oxides in nickel liquid.

[0024] (2) During solidification, rare earth oxides can serve as heterogeneous nucleation sites for the γ phase of the GH4169 matrix. Both La2O3 and Ce2O3 belong to the hexagonal system, with space groups of The lattice constants of La2O3 are a=0.3846nm、c=0.6216nm, and the lattice constants of Ce2O3 are a=0.3891nm、c=0.6059nm. The γ phase belongs to the cubic system, and the space group is The lattice constant a = 0.3517nm. The low-index planes of La2O3 (Ce2O3) and the γ phase are the (0001) and (100) planes, respectively. From this, the two-dimensional mismatches of La2O3 and Ce2O3 with the γ phase can be calculated to be 5.67% and 5.34%, respectively. According to Bramfitt's two-dimensional mismatch theory, during heterogeneous nucleation, a mismatch of less than 6% indicates strong nucleation. Therefore, the rare earth oxides La2O3 and Ce2O3 can serve as strong and effective heterogeneous nucleation sites for the γ phase, significantly increasing the deformation nucleation rate of the GH4169 phase, refining the grains, and achieving a uniform solidification structure.

[0025] (3) Rare earth oxides can reduce Laves phase precipitation. In GH4169, Laves phase precipitates between dendrites. The coarser the grains, the more severe the interdendritic segregation, and the more Laves phase precipitation occurs. Because La2O3 and Ce2O3 can refine the GH4169 grains, interdendritic segregation will be significantly reduced, and the precipitation of the brittle Laves phase will also be significantly reduced. Therefore, the strength and plasticity of GH4169 will be greatly enhanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a microstructure photograph of the GH4169 ingot prepared in Comparative Example 1.

[0027] Figure 2 This is a microstructure photograph of the GH4169 ingot prepared in Example 1.

[0028] Figure 3 This is a microstructure photograph of the GH4169 ingot prepared in Example 2.

[0029] Figure 4 This is a microstructure photograph of the GH4169 ingot prepared in Example 3. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0031] Example 1

[0032] GH4169 containing rare earth oxides is produced using a 1t vacuum induction furnace, a 1t protective atmosphere electroslag furnace, a 1000t air rapid forging machine and other equipment. The production process is as follows:

[0033] (1) Preparation of rare earth oxide particles

[0034] Analytical pure rare earth oxide La2O3 and nickel powder were ground into 50-500 nm using a ball mill, respectively, with a ball-to-material ratio of 8:1, a rotation speed of 450 r / min, argon protection, and a ball milling time of 3 h.

[0035] The ground La2O3 and nickel powder were mixed evenly in a ball mill at a mass ratio of 0.2:1, a ball-to-material ratio of 8:1, a rotation speed of 200 r / min, argon protection, and a mixing time of 1.5 h;

[0036] The mixture was isostatically sintered at 1260°C, a pressure of 150 MPa, and a sintering time of 5 h;

[0037] The sintered blocks are crushed into particles of 3 to 5 mm in size.

[0038] (2) Vacuum induction furnace smelting

[0039] Charging the furnace: 400 g of the rare earth oxide particles prepared in step (1) are evenly spread on the bottom of the crucible, and 100 kg of nickel plate, 50 kg of metallic chromium, and 50 kg of pure iron are placed on top in sequence; then 400 g of the rare earth oxide particles prepared in step (1) are evenly spread, and then 150 kg of nickel plate, 50 kg of metallic chromium, 50 kg of pure iron, 30 kg of molybdenum bars, and 55 kg of niobium bars are placed; then 400 g of the rare earth oxide particles prepared in step (1) are evenly spread, and then 280 kg of nickel plate, 70 kg of metallic chromium, and 80 kg of pure iron are placed.

[0040] Melting and alloying: Combine the furnaces, evacuate to 3 Pa, power on for melting, control the power, and melt thoroughly after 3 hours; refine for 40 minutes; stop the vacuum and fill with argon to 10,000 Pa; add 5 kg aluminum, 11 kg titanium, and 400 g carbon powder; take samples for testing and adjust the composition; raise the temperature to 1520°C after the composition is qualified;

[0041] Casting: Cast into Ф300*1800mm electrode.

[0042] (3) Electroslag remelting

[0043] Preparation: Grind and weld the electrode surface; weigh 50 kg of pre-melted slag and bake it in a 600°C furnace for 8 hours. The slag composition is: 50% CaF2, 20% CaO, 20% Al2O3, 3% TiO2, 6.5% MgO, and 0.5% La2O3;

[0044] Melting: Using Ф380*1500mm crystallizer for melting; argon protection throughout the process;

[0045] Demolding: Demolding 60 minutes after smelting.

[0046] (4) Homogenization

[0047] The electroslag ingot was placed in a heating furnace, heated to 1160°C over 6.5 hours, kept at this temperature for 30 hours, then heated to 1190°C, kept at this temperature for 40 hours, and then removed from the furnace and air-cooled.

[0048] (5) Forging

[0049] GH4169 ingots are forged at 960-1160℃ to form Ø80mm round bars and air-cooled after forging.

[0050] (6) Solid solution and aging

[0051] Place the forging in a heating furnace, keep it at 960℃ for 1 hour, and air cool it; then keep it in a furnace at 720℃ for 8 hours, cool it to 620℃ with the furnace at a rate of ≤50℃ / h, keep it for 8 hours, and air cool it to room temperature.

[0052] Comparative Example 1

[0053] (1) Vacuum induction furnace smelting

[0054] Charging the furnace: Place 100kg nickel plate, 50kg metallic chromium, and 50kg pure iron at the bottom of the crucible in sequence; place 150kg nickel plate, 50kg metallic chromium, 50kg pure iron, 30kg molybdenum bar, and 55kg niobium bar in the middle of the crucible; place 280kg nickel plate, 70kg metallic chromium, and 80kg pure iron on the upper part of the crucible.

[0055] Melting and alloying: Combine the furnaces, evacuate to 3 Pa, power on for melting, control the power, and melt thoroughly after 3 hours; refine for 40 minutes; stop the vacuum and fill with argon to 10,000 Pa; add 5 kg aluminum, 11 kg titanium, and 400 g carbon powder; take samples for testing and adjust the composition; raise the temperature to 1520°C after the composition is qualified;

[0056] Casting: Cast into Ф300*1800mm electrode.

[0057] (2) Electroslag remelting

[0058] Preparation: Grind and weld the electrode surface; weigh 50 kg of pre-melted slag and bake it in a 600°C furnace for 8 hours. The slag composition is: 50% CaF2, 20% CaO, 20% Al2O3, 3.5% TiO2, 6.5% MgO;

[0059] Melting: Using Ф380*1500mm crystallizer for melting; argon protection throughout the process;

[0060] Demolding: Demolding 60 minutes after smelting.

[0061] (3) Homogenization

[0062] The electroslag ingot was placed in a heating furnace, heated to 1160°C over 6.5 hours, kept at this temperature for 30 hours, then heated to 1190°C, kept at this temperature for 40 hours, and then removed from the furnace and air-cooled.

[0063] (4) Forging

[0064] The ingot is forged at 960-1160℃ to form Ø80mm round bars and air-cooled after forging.

[0065] (5) Solid solution and aging

[0066] Place the forging in a heating furnace, keep it at 960℃ for 1 hour, and air cool it; then keep it in a furnace at 720℃ for 8 hours, cool it to 620℃ with the furnace at a rate of ≤50℃ / h, keep it for 8 hours, and air cool it to room temperature.

[0067] Example 2

[0068] GH4169 containing rare earth oxide particles is produced using a 2t vacuum induction furnace, a 2t protective atmosphere electroslag furnace, a 1000t air rapid forging machine and other equipment. The production process is as follows:

[0069] (1) Preparation of rare earth oxide particles

[0070] Analytical pure Ce2O3 and nickel powder were ground into 50-500 nm respectively using a ball mill with a ball-to-material ratio of 8:1, a rotation speed of 500 r / min, argon protection, and a ball milling time of 3.5 h.

[0071] The ground Ce2O3 and nickel powder were mixed evenly in a ball mill at a mass ratio of 0.3:1, a ball-to-material ratio of 9:1, a rotation speed of 250 r / min, argon protection, and a mixing time of 2 h;

[0072] The mixture was isostatically sintered at 1300°C, a pressure of 180 MPa, and a sintering time of 5.5 h.

[0073] The sintered blocks are crushed into particles of 3 to 5 mm in size.

[0074] (2) Vacuum induction furnace smelting

[0075] Charging the furnace: evenly spread 1000 g of the rare earth oxide particles prepared in step (1) on the bottom of the crucible, and then place 200 kg of nickel plate, 100 kg of metallic chromium, and 100 kg of pure iron on top in sequence; then evenly sprinkle 1000 g of the rare earth oxide particles prepared in step (1), and then place 300 kg of nickel plate, 100 kg of metallic chromium, 100 kg of pure iron, 60 kg of molybdenum bars, and 110 kg of niobium bars; then evenly sprinkle 600 g of the rare earth oxide particles prepared in step (1), and then place 560 kg of nickel plate, 140 kg of metallic chromium, and 160 kg of pure iron.

[0076] Melting and alloying: Combine the furnaces, evacuate to 1Pa, power on for melting, control the power, and melt thoroughly after 5 hours; refine for 60 minutes; stop the vacuum and fill with argon to 20,000Pa; add 10kg aluminum, 22kg titanium, and 800g carbon powder; take samples for testing and adjust the composition; raise the temperature to 1540°C after the composition is qualified;

[0077] Casting: Cast into Ф400*2200mm electrode.

[0078] (3) Electroslag remelting

[0079] Preparation: Grind and weld the electrode surface; weigh 100 kg of pre-melted slag and bake it in an 800°C furnace for 8 hours. The slag composition is: 50% CaF2, 20% CaO, 20% Al2O3, 3% TiO2, 5.5% MgO, 1.5% Ce2O3;

[0080] Melting: Using Ф530*1500mm crystallizer for melting; argon protection throughout the process;

[0081] Demolding: demoulding 120 minutes after smelting.

[0082] (4) Homogenization

[0083] Place the electroslag ingot in a heating furnace, heat it to 1160°C over 8 hours, keep it at that temperature for 30 hours, then heat it to 1190°C and keep it at that temperature for 40 hours. Then take it out of the furnace and air cool it.

[0084] (5) Forging

[0085] GH4169 ingots are forged at 960-1160℃ into 100mm Ø round bars and air-cooled after forging.

[0086] (6) Solid solution and aging

[0087] Place the forging in a heating furnace, keep it at 960℃ for 1 hour, and air cool it; then keep it in a furnace at 720℃ for 8 hours, cool it to 620℃ with the furnace at a rate of ≤50℃ / h, keep it for 8 hours, and air cool it to room temperature.

[0088] Comparative Example 2

[0089] (1) Vacuum induction furnace smelting

[0090] Charging the furnace: Evenly place 200kg nickel plates, 100kg metallic chromium, and 100kg pure iron on the bottom of the crucible; place 300kg nickel plates, 100kg metallic chromium, 100kg pure iron, 60kg molybdenum bars, and 110kg niobium bars in the middle; and evenly place 560kg nickel plates, 140kg metallic chromium, and 160kg pure iron on the top.

[0091] Melting and alloying: Combine the furnaces, evacuate to ≤1Pa, power on and melt, control the power, and melt thoroughly after 5 hours; refine for 60 minutes; stop the vacuum and fill with argon to 20,000Pa; add 10kg aluminum, 22kg titanium, and 800g carbon powder; take samples for testing and adjust the composition; raise the temperature to 1540°C after the composition is qualified;

[0092] Casting: Cast into Ф400*2200mm electrode.

[0093] (2) Electroslag remelting

[0094] Preparation: Grind and weld the electrode surface; weigh 100 kg of pre-melted slag and bake it in an 800°C furnace for 8 hours. The slag composition is: 50% CaF2, 20% CaO, 20% Al2O3, 3% TiO2, 5.5% MgO, 1.5% Ce2O3;

[0095] Melting: Using Ф530*1500mm crystallizer for melting; argon protection throughout the process;

[0096] Demolding: demoulding 120 minutes after smelting.

[0097] (3) Homogenization

[0098] Place the electroslag ingot in a heating furnace, heat it to 1160°C over 8 hours, keep it at that temperature for 30 hours, then heat it to 1190°C and keep it at that temperature for 40 hours. Then take it out of the furnace and air cool it.

[0099] (4) Forging

[0100] The ingot is forged at 960-1160℃ to form 100mm Ø round bars and air-cooled after forging.

[0101] (5) Solid solution and aging

[0102] Place the forging in a heating furnace, keep it at 960℃ for 1 hour, and air cool it; then keep it in a furnace at 720℃ for 8 hours, cool it to 620℃ with the furnace at a rate of ≤50℃ / h, keep it for 8 hours, and air cool it to room temperature.

[0103] Example 3

[0104] GH4169 containing rare earth oxide particles is produced using a 1t vacuum induction furnace, a 1t protective atmosphere electroslag furnace, a 1000t air rapid forging machine and other equipment. The production process is as follows:

[0105] (1) Preparation of rare earth oxide particles

[0106] Analytical pure La2O3, Ce2O3 and nickel powder were ground into 50-500 nm using a ball mill, with a ball-to-material ratio of 8.5:1, a rotation speed of 480 r / min, argon protection, and a ball milling time of 3.5 h.

[0107] The ground La2O3, Ce2O3 and nickel powder were mixed uniformly in a ball mill at a mass ratio of 0.1:0.1:1, a ball-to-material ratio of 8.5:1, a rotation speed of 250 r / min, argon protection, and a mixing time of 2 h;

[0108] The mixture was isostatically sintered at 1300°C, a pressure of 180 MPa, and a sintering time of 5.5 h.

[0109] The sintered block material is crushed into particles of 3 to 5 mm in size.

[0110] (2) Vacuum induction furnace smelting

[0111] Charging the furnace: 500 g of the rare earth oxide particles prepared in step (1) are evenly spread on the bottom of the crucible, and 100 kg of nickel plate, 50 kg of metallic chromium, and 50 kg of pure iron are placed on top in sequence; then 500 g of the rare earth oxide particles prepared in step (1) are evenly sprinkled, and then 150 kg of nickel plate, 50 kg of metallic chromium, 50 kg of pure iron, 30 kg of molybdenum bars, and 55 kg of niobium bars are placed; then 500 g of the rare earth oxide particles prepared in step (1) are evenly sprinkled, and then 280 kg of nickel plate, 70 kg of metallic chromium, and 80 kg of pure iron are placed.

[0112] Melting and alloying: Combine the furnaces, evacuate to 3 Pa, power on for melting, control the power, and melt thoroughly after 3 hours; refine for 40 minutes; stop the vacuum and fill with argon to 10,000 Pa; add 5 kg aluminum, 11 kg titanium, and 400 g carbon powder; take samples for testing and adjust the composition; raise the temperature to 1520°C after the composition is qualified;

[0113] Casting: Cast into Ф300*1800mm electrode.

[0114] (3) Electroslag remelting

[0115] Preparation: Grind and weld the electrode surface; weigh 50 kg of pre-melted slag and bake it in a 600°C furnace for 8 hours. The slag composition is: 50% CaF2, 20% CaO, 20% Al2O3, 3% TiO2, 6% MgO, 0.5% La2O3, 0.5% Ce2O3;

[0116] Melting: Using Ф380*1500mm crystallizer for melting; argon protection throughout the process;

[0117] Demolding: Demolding 60 minutes after smelting.

[0118] (4) Homogenization

[0119] The electroslag ingot was placed in a heating furnace, heated to 1160°C over 6.5 hours, kept at this temperature for 30 hours, then heated to 1190°C, kept at this temperature for 40 hours, and then removed from the furnace and air-cooled.

[0120] (5) Forging

[0121] GH4169 ingots are forged at 960-1160℃ to form Ø80mm round bars and air-cooled after forging.

[0122] (6) Solid solution and aging

[0123] Place the forging in a heating furnace, keep it at 960℃ for 1 hour, and air cool it; then keep it in a furnace at 720℃ for 8 hours, cool it to 620℃ with the furnace at a rate of ≤50℃ / h, keep it for 8 hours, and air cool it to room temperature.

[0124] Comparative Example 3

[0125] (1) Vacuum induction furnace smelting

[0126] Charging the furnace: Place 100kg nickel plate, 50kg metallic chromium, and 50kg pure iron at the bottom of the crucible in sequence; place 150kg nickel plate, 50kg metallic chromium, 50kg pure iron, 30kg molybdenum bar, and 55kg niobium bar in the middle of the crucible; place 280kg nickel plate, 70kg metallic chromium, and 80kg pure iron on the upper part of the crucible.

[0127] Melting and alloying: Combine the furnaces, evacuate to 3 Pa, power on for melting, control the power, and melt thoroughly after 3 hours; refine for 40 minutes; stop the vacuum and fill with argon to 10,000 Pa; add 5 kg aluminum, 11 kg titanium, and 400 g carbon powder; take samples for testing and adjust the composition; raise the temperature to 1520°C after the composition is qualified;

[0128] Casting: Cast into Ф300*1800mm electrode.

[0129] (2) Electroslag remelting

[0130] Preparation: Grind and weld the electrode surface; weigh 50 kg of pre-melted slag and bake it in a 600°C furnace for 8 hours. The slag composition is: 50% CaF2, 20% CaO, 20% Al2O3, 3.5% TiO2, 6.5% MgO;

[0131] Melting: Using Ф380*1500mm crystallizer for melting; argon protection throughout the process;

[0132] Demolding: Demolding 60 minutes after smelting.

[0133] (3) Homogenization

[0134] The electroslag ingot was placed in a heating furnace, heated to 1160°C over 6.5 hours, kept at this temperature for 30 hours, then heated to 1190°C, kept at this temperature for 40 hours, and then removed from the furnace and air-cooled.

[0135] (4) Forging

[0136] The ingot is forged at 960-1160℃ to form Ø80mm round bars and air-cooled after forging.

[0137] (5) Solid solution and aging

[0138] Place the forging in a heating furnace, keep it at 960℃ for 1 hour, and air cool it; then keep it in a furnace at 720℃ for 8 hours, cool it to 620℃ with the furnace at a rate of ≤50℃ / h, keep it for 8 hours, and air cool it to room temperature.

[0139] The structure of GH4169 electroslag ingot prepared in Comparative Example 1 is as follows: Figure 1 As shown by Figure 1 It can be seen that the electroslag ingots produced by traditional technology have coarse dendrites, and there are more white Laves phases precipitated between the dendrites (black areas), and most of them are continuous and chain-like.

[0140] The GH4169 ingot structure prepared in Example 1-3 is as follows: Figure 2-Figure 4 shown by Figure 2-Figure 4 It can be seen that the electroslag ingot prepared by the method of the present invention has fine dendrites, and the Laves phase precipitated between the dendrites is also small and dispersed.

[0141] The mechanical properties of the finished products prepared in Examples 1-3 and Comparative Examples 1-3 were analyzed, and the results are shown in Table 1.

[0142] Table 1 Mechanical properties of forgings of Examples and Comparative Examples 1-3

[0143]

[0144] As shown in Table 1, the mechanical properties of GH4169 have been greatly improved after the addition of rare earth oxides. At room temperature, the strength, elongation and cross-sectional shrinkage have increased by more than 10%. At 650 ° C, the strength and elongation have also increased by more than 10%, indicating that the strength and plasticity have been greatly improved.

[0145] The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the present invention can still be modified or replaced by equivalents. Any modification or partial replacement that does not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A high-strength high-temperature alloy, characterized in that: The high-strength high-temperature alloy includes a high-temperature alloy matrix and rare earth oxides dispersed in the high-temperature alloy matrix; the high-temperature alloy matrix is ​​GH4169; the rare earth oxides are one or two of La2O3 and Ce2O3, with a particle size of 50 to 500 nm and a total amount added of 0.02 to 0.03% of the alloy mass.

2. The method for preparing the high-strength high-temperature alloy according to claim 1, characterized in that: (1) Preparation of rare earth oxide particles; (2) Vacuum induction melting: 30% to 40% of the total amount of rare earth oxide particles are evenly spread on the bottom of the crucible, and then the alloy material is spread on it to 1 / 3 to 1 / 2 of the crucible height, and then 30% to 40% of the total amount of rare earth oxide particles are evenly sprinkled in, and then the alloy material is spread to 2 / 3 to 3 / 4 of the crucible height, and the remaining amount of rare earth oxide particles are evenly sprinkled in, and finally the alloy material is spread to the furnace mouth; after the materials are spread, the furnace is closed, vacuum melting is carried out, and after the composition is qualified, it is cast into a consumable electrode; (3) Electroslag remelting: argon protection is used throughout the process, and 0.5-1.5% of the analytically pure rare earth oxide in the rare earth oxide particles in step (1) is added to the slag system to obtain an electroslag ingot; (4) The electroslag ingot is subjected to homogenization, forging, and solid solution aging treatment in sequence to obtain the finished product.

3. The method for preparing a high-strength high-temperature alloy according to claim 2, characterized in that: The preparation method of the rare earth oxide particles in step (1) is as follows: Analytical pure rare earth oxides La2O3, Ce2O3 and nickel powder were mechanically ground to 50-500 nm respectively; Mix the rare earth oxide and nickel powder in a mass ratio of (0.2-0.3):1; The mixed material is isostatically sintered at 1260-1300°C, a pressure of 150-180 MPa, and a sintering time of 5-5.5 hours; The sintered block material is crushed into particles of 3 to 5 mm in size.

4. The method for preparing a high-strength high-temperature alloy according to claim 3, characterized in that: The analytically pure rare earth oxide and nickel powder are ground to 50-500 nm using a ball mill. During the grinding process, the ball-to-material ratio is (8-9):1, the rotation speed is 450-500 r / min, argon protection is used, and the ball milling time is 3-3.5 h.

5. The method for preparing a high-strength high-temperature alloy according to claim 3, characterized in that: The rare earth oxide and nickel powder are uniformly mixed in a ball mill with a ball-to-material ratio of (8-9):1, a rotation speed of 200-250 r / min, argon protection, and a mixing time of 1.5-2 hours.

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