A nickel-based cast high-temperature alloy with improved creep resistance and lifetime, a preparation method, a device and a hot end component

Abstract

A nickel-based cast high-temperature alloy with improved creep resistance and service life, a preparation method and device, and a hot end component, the alloy comprising: C 0.14-0.20%, Cr 8.0-9.0%, Co 9.0-11.0%, Al 5.3-5.7%, Ti 0.5-1.5%, Ta 2.8-3.3%, W 9.5-10.5%, Mo 0.4-0.8%, Hf 1.2-1.6%, B 0.01-0.02%, Zr 0.02-0.08%, Sc 0.001-0.2%, and satisfying 6.2%≤Al+Ti+Mo≤8.0% and 5.0%≤Al+Sc+Ti≤7.5%, wherein the percentages represent the mass percentage of the corresponding elements. The preparation method comprises the following steps: vacuum induction melting and refining to obtain an alloy melt; adding Sc after refining and before pouring the alloy melt; precision casting the alloy melt after adding Sc, and solid solution and aging treatment of the castings to obtain the nickel-based cast high-temperature alloy. The preparation device comprises a vacuum feeding device. Sc is rapidly and uniformly fed under inert atmosphere protection, and the addition of Sc is beneficial to improving the microstructure stability of the alloy under high-temperature long-term service conditions, thereby improving the creep resistance and service life of the alloy.

Description

Technical Field

[0001] This invention relates to the field of nickel-based casting alloy technology, specifically to a nickel-based casting high-temperature alloy with improved creep resistance and lifespan, its preparation method, apparatus, and hot-end components. Background Technology

[0002] Nickel-based cast superalloys are commonly used in hot-end components of equipment such as aero engines and gas turbines. These components are subjected to high temperatures and stresses for extended periods during service, thus requiring materials with good creep resistance, long service life, and structural stability.

[0003] Nickel-based cast superalloys, represented by M247, are a typical class of precipitation-strengthened nickel-based cast superalloys. They typically achieve high-temperature strength through microstructures such as the γ matrix, γ' strengthening phases, and grain boundary carbides. These alloys possess good casting properties and certain high-temperature mechanical properties, making them suitable for manufacturing precision-cast hot-end components such as turbine blades and guide vanes.

[0004] However, under long-term service conditions above 950℃ or high stress, existing nickel-based cast superalloys still suffer from insufficient creep resistance and servicing life. This is due to two main reasons: firstly, carbides at grain boundaries tend to coarsen under prolonged high temperatures, exhibiting a continuous chain or lamellar distribution, leading to a decrease in the plastic deformation capacity of grain boundaries; secondly, impurities such as O, S, and P tend to segregate at grain boundaries, reducing grain boundary bonding strength. Under the synergistic effect of these factors, creep voids easily nucleate and propagate at grain boundaries during high-temperature stress service, ultimately inducing intergranular cracking in the alloy.

[0005] To further improve the heat resistance of hot-end component materials, existing technologies mainly employ directionally solidified superalloys or single-crystal superalloys. While directionally solidified superalloys can effectively reduce transverse grain boundaries, longitudinal grain boundaries remain difficult to eliminate, and the preparation process requires high precision. Single-crystal superalloys can completely eliminate grain boundaries, but their preparation process is complex, yield is low, and some alloys require the addition of precious metals such as Re, which not only increases material costs but also restricts large-scale mass production. Furthermore, the vacuum melting feeding devices in existing technologies are all conventional feeding structures, which cannot effectively protect active rare earth elements, especially active rare earth elements such as Sc, which are easily burned off and volatilized under high-temperature vacuum, thus affecting the performance of the finished alloy.

[0006] Therefore, there is a need to provide a nickel-based cast superalloy, a preparation method, an apparatus, and a hot-end component, so that it can obtain good creep resistance and service life under conventional precision casting process conditions, while taking into account material cost and engineering feasibility. Summary of the Invention

[0007] To address the aforementioned problems, this invention provides a nickel-based cast superalloy with improved creep resistance and lifespan, its preparation method, and a hot-end component.

[0008] The technical solution adopted by this invention to solve the above problems is as follows: a nickel-based cast superalloy for improving creep resistance and service life, wherein the composition of the nickel-based cast superalloy, by mass percentage, includes: C 0.14-0.20%, Cr 8.0-9.0%, Co 9.0-11.0%, Al 5.3-5.7%, Ti 0.5-1.5%, Ta 2.8-3.3%, W 9.5-10.5%, Mo 0.4-0.8%, H The content of f is 1.2-1.6%, B is 0.01-0.02%, Zr is 0.02-0.08%, Sc is 0.001-0.2%, and the balance is Ni and impurities; the nickel-based cast high-temperature alloy forms an Al and Ti composite precipitate strengthening phase containing Sc, and satisfies 6.2%≤Al+Ti+Mo≤8.0% and 5.0%≤Al+Sc+Ti≤7.5%, where Al, Ti, Mo and Sc represent the mass percentage content of the corresponding elements.

[0009] As an optimization, the nickel-based cast superalloy satisfies 6.15%≤Al+Sc+Ti≤7.15%.

[0010] As an optimization, the mass percentage of the impurities is not higher than 0.015% for S, 0.15% for Si, 0.15% for Mn, and 0.35% for Fe.

[0011] As an optimization, the nickel-based cast superalloy has a creep rupture life of not less than 225 hours under 870℃ / 390MPa conditions, and / or a creep rupture life of not less than 77 hours under 980℃ / 220MPa conditions.

[0012] As an optimization, the nickel-based cast superalloy is an M247 type nickel-based cast superalloy, or an alloy obtained by microalloying any one of the nickel-based cast superalloys IN738, IN792, Rene80, K417, IN716, IN706, IN713C, and K418 using Sc.

[0013] A method for preparing a nickel-based cast superalloy, including the aforementioned nickel-based cast superalloy with improved creep resistance and lifespan, specifically includes the following steps: First, vacuum induction melting and refining are performed according to the target composition to obtain an alloy melt; then, Sc is added to the alloy melt after refining and before casting; finally, the alloy melt with added Sc is precision cast, and the casting is subjected to solution treatment and aging treatment to obtain the nickel-based cast superalloy.

[0014] As an optimization, Sc is added in the form of pure Sc, Ni-Sc master alloy or Sc-containing alloy additive; Sc is added 5 to 10 minutes before casting, and the alloy melt temperature is not higher than 1480℃ when Sc is added; in addition, the mixture is stirred for 2 to 3 minutes after adding Sc.

[0015] As an optimization, the vacuum degree of the vacuum induction melting is not higher than 0.1 Pa, and the melting temperature is 1520-1550℃; the refining is carried out under a vacuum degree of 0.1-0.5 Pa for 30-40 minutes; the precision casting is to pour the alloy melt into a ceramic mold shell with a preheating temperature of 850-1000℃.

[0016] As an optimization, the solution and aging treatment includes: first, holding at 1210℃±10℃ for 2 hours and then air cooling to achieve solution of alloying elements; then, holding at 870℃±10℃ for 16 hours and then air cooling to achieve initial aging precipitation; finally, holding at 760℃±10℃ for 16 hours and then air cooling to complete secondary aging precipitation.

[0017] A preparation apparatus for manufacturing the nickel-based casting high-temperature alloy described in any one of the above, comprising a vacuum melting furnace, wherein the vacuum melting furnace is equipped with a vacuum feeding device, the vacuum feeding device comprising a vacuum feeding barrel, wherein a feeding pipe is connected to the waist of the vacuum feeding barrel, and a gas connection port is provided at the top of the vacuum feeding barrel, wherein a vacuum pump and a vent pipe are connected to the gas connection port, the vent pipe being connected to an argon gas source, wherein a feeding assembly is provided inside the vacuum feeding barrel, the feeding assembly comprising a drive motor and a feeding plug, wherein a retractable drive rod is connected between the output shaft of the drive motor and the feeding plug, wherein after Sc is fed, it falls onto the feeding plug, and the drive motor drives the feeding plug to rotate, so that Sc is evenly distributed on the outer edge of the upper surface of the feeding plug; The vacuum feeding barrel is equipped with an auxiliary plate inside. The auxiliary plate moves along the axis of the vacuum feeding barrel under the action of air pressure, forming a pressurization zone on the upper side of the feed plug. The drive rod extends, the feed plug enters the vacuum melting furnace, and the argon gas in the pressurization zone blows the Sc powder into the vacuum melting furnace rapidly.

[0018] A hot-end component comprising the nickel-based cast superalloy described in any one of the preceding claims, wherein the nickel-based cast superalloy is prepared by the preparation method described in any one of the preceding claims.

[0019] The beneficial effects of this plan are as follows: This invention adds Sc to a nickel-based cast superalloy and controls the content relationship of elements such as Sc, Al, Ti and Mo to form an Al and Ti composite precipitate strengthening phase containing Sc in the alloy. This is beneficial to improving the thermal stability of the precipitate phase, thereby improving the microstructure stability of the alloy under long-term high-temperature service conditions, and thus improving its creep resistance and service life.

[0020] This invention limits the content of Al, Ti, Mo and Sc to 6.2% ≤ Al + Ti + Mo ≤ 8.0% and 5.0% ≤ Al + Sc + Ti ≤ 7.5%, so that the contents of Al, Ti, Mo and Sc are kept within an appropriate range, which is beneficial to obtaining a more stable precipitated strengthening phase and reducing the risk of decreased tissue stability due to improper content of strengthening elements.

[0021] In this invention, the addition of Sc can purify the alloy melt, reduce the unfavorable segregation of impurity elements such as O, S, and P at the grain boundaries, and help improve the grain boundary state of the as-cast structure, thereby strengthening the grain boundaries. On the other hand, it can improve the distribution state of grain boundary carbides, achieve their fine and dispersed distribution, and thus suppress the tendency of grain boundary slip and creep void nucleation during high-temperature creep.

[0022] The preparation apparatus of this application enables a low-oxygen, short-time, and dispersed injection feeding method, which can reduce the probability of Sc oxidation and burn-off or local enrichment near the feeding port, and reduce the risk of introducing impurities such as O, S, and P due to disruption of the furnace vacuum.

[0023] The nickel-based casting high-temperature alloy of the present invention can be prepared by vacuum induction melting, precision casting, solution treatment and aging treatment. The process route is compatible with the conventional nickel-based casting high-temperature alloy preparation process, which is beneficial to the preparation of hot-end component castings. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the vacuum feeding device of the present invention from the side.

[0025] Figure 2 This is a front view schematic diagram of the vacuum feeding device of the present invention.

[0026] Figure 3 For the present invention Figure 2 A schematic diagram of the AA cross-section structure.

[0027] Figure 4 For the present invention Figure 3 A schematic diagram of the BB cross-section structure.

[0028] Among them, 1. Vacuum feeding barrel, 2. Feed pipe, 3. Gas connection port, 4. Drive motor, 5. Feed plug, 6. Drive rod, 7. Auxiliary plate, 8. Telescopic rod, 9. Auxiliary electromagnet, 10. Slot, 11. Guide rail, 12. Drive electromagnet. Detailed Implementation

[0029] A nickel-based cast superalloy for improving creep resistance and lifespan, wherein the nickel-based cast superalloy composition by mass percentage comprises: C 0.14-0.20%, Cr 8.0-9.0%, Co 9.0-11.0%, Al 5.3-5.7%, Ti 0.5-1.5%, Ta 2.8-3.3%, W 9.5-10.5%, Mo 0.4-0.8%, Hf 1.2-1.6%, B 0.01-0.02%, Zr 0.02-0.08%, Sc 0.001-0.2%, with the balance being Ni and impurities; the nickel-based cast superalloy forms an Al-Ti composite precipitate strengthening phase containing Sc, and satisfies 6.2%≤Al+Ti+Mo≤8.0% and 5.0%≤Al+Sc+Ti≤7.5%, wherein Al, Ti, Mo and Sc represent the mass percentage content of the corresponding elements.

[0030] The nickel-based cast superalloy satisfies 6.15%≤Al+Sc+Ti≤7.15%.

[0031] The impurities include S≤0.015%, Si≤0.15%, Mn≤0.15%, and Fe≤0.35%.

[0032] The nickel-based cast superalloy has a creep rupture life of not less than 225 hours under 870℃ / 390MPa conditions, and / or a creep rupture life of not less than 77 hours under 980℃ / 220MPa conditions.

[0033] The nickel-based cast superalloy is an M247 type nickel-based cast superalloy, or an alloy obtained by microalloying any one of the nickel-based cast superalloys IN738, IN792, Rene80, K417, IN716, IN706, IN713C, and K418 using Sc.

[0034] A method for preparing a nickel-based cast high-temperature alloy, including the aforementioned nickel-based cast high-temperature alloy with improved creep resistance and lifespan, specifically includes the following steps: First, vacuum induction melting and refining are performed according to the target composition to obtain an alloy melt; then, Sc is added to the alloy melt after refining and before casting; finally, the alloy melt with added Sc is precision cast, and the casting is subjected to solution treatment and aging treatment to obtain the nickel-based cast high-temperature alloy.

[0035] The target components, by mass percentage, include: C 0.14-0.20%, Cr 8.0-9.0%, Co 9.0-11.0%, Al 5.3-5.7%, Ti 0.5-1.5%, Ta 2.8-3.3%, W 9.5-10.5%, Mo 0.4-0.8%, Hf 1.2-1.6%, B 0.01-0.02%, Zr 0.02-0.08%, with the balance being Ni and impurities; Sc 0.001-0.2%. The Sc is added in the form of pure Sc, Ni-Sc master alloy or Sc-containing alloy additive; the Sc is added 5 to 10 minutes before casting, the temperature of the alloy melt is not higher than 1480℃ when Sc is added, and the mixture is stirred for 2 to 3 minutes after adding Sc.

[0036] The vacuum induction melting is performed with a vacuum degree not exceeding 0.1 Pa and a melting temperature of 1520–1550 °C; the refining is performed under a vacuum degree of 0.1–0.5 Pa for 30–40 minutes; the precision casting is performed by pouring the alloy melt into a ceramic mold shell with a preheating temperature of 850–1000 °C.

[0037] The solution treatment and aging process includes: first, holding at 1210℃±10℃ for 2 hours and then air cooling; then holding at 870℃±10℃ for 16 hours and then air cooling; and finally holding at 760℃±10℃ for 16 hours and then air cooling.

[0038] Based on the above, Examples 1-3 and Comparative Examples 1-3 were set up, and the above examples and comparative examples were manufactured according to the nickel-based casting high-temperature alloy preparation method of this application. The final composition of each example and comparative example is shown in the table below: Table 1: Composition of Examples 1-3 and Comparative Examples 1-3, in wt.%.

[0039] The performance of the nickel-based cast superalloys obtained in Examples 1-3 and Comparative Examples 1-3 was tested, and the test results are as follows: Table 2: Performance Test Tables of Examples 1-3 and Comparative Examples 1-3 (Exemplary Data): As can be seen from the comparison of Tables 1 and 2, after introducing Sc into the nickel-based cast superalloy and controlling the composition ratio of Al+Ti+Mo and Al+Sc+Ti, the example is superior to the comparative example in terms of creep life, creep rate and plasticity index, indicating that the present invention can effectively improve the creep resistance and service life of the alloy.

[0040] like Figures 1-4As shown, the preparation apparatus is used to manufacture the nickel-based casting high-temperature alloy described in any of the above-mentioned embodiments. It includes a vacuum melting furnace, which is equipped with a vacuum feeding device. The vacuum feeding device includes a vacuum feeding barrel 1. A feeding pipe 2 is connected to the waist of the vacuum feeding barrel 1. A gas connection port 3 is provided at the top of the vacuum feeding barrel 1. The gas connection port 3 is connected to a vacuum pump and a vent pipe. The vent pipe is connected to an argon gas source. A feeding assembly is provided inside the vacuum feeding barrel 1. The feeding assembly includes a drive motor 4 and a feeding plug 5. A retractable drive rod 6 is connected between the output shaft of the drive motor 4 and the feeding plug 5. After the Sc is fed, it falls onto the feeding plug 5. The drive motor 4 drives the feeding plug 5 to rotate, so that the Sc is evenly distributed on the outer edge of the upper surface of the feeding plug 5. The vacuum feeding barrel 1 is equipped with an auxiliary plate 7 inside. The auxiliary plate 7 moves along the axis of the vacuum feeding barrel 1 under the action of air pressure, forming a pressurization zone on the upper side of the feed plug 5. The drive rod 6 extends, the feed plug 5 enters the vacuum melting furnace, and the argon gas in the pressurization zone blows the Sc powder into the vacuum melting furnace quickly.

[0041] The feed pipe 2 is equipped with a feed valve to control the feeding of Sc powder. The connection between the feed pipe 2 and the vacuum feeding tank 1 is inclined downwards for easy feeding. The bottom of the vacuum feeding tank 1 is directly connected to the upper part of the vacuum melting furnace.

[0042] The upper part of the vacuum feeding tank 1 is equipped with a fixed platform, which is used to fix the drive motor 4. The drive motor 4 is used to drive the drive rod 6 and the feed plug 5 to rotate. The upper surface of the feed plug 5 is a downward conical surface, and the side of the feed plug 5 is in contact with and sealed to the inner wall of the vacuum feeding tank 1.

[0043] The outer periphery of the auxiliary plate 7 is in contact with and sealed to the inner wall of the vacuum feeding tank 1. The auxiliary plate 7, drive rod 6, feed plug 5, and vacuum feeding tank 1 are all coaxially arranged. The auxiliary plate 7 is located on the lower side of the fixed platform.

[0044] The connection between the feed pipe 2 and the vacuum feeding tank 1 is located on the lower side of the fixed platform. The fixed platform is also fixed with a telescopic rod 8 for driving the auxiliary plate 7 to move. The auxiliary plate 7 can move up to the lower side of the extended end of the telescopic rod 8. An auxiliary electromagnet 9 is provided at the extended end of the telescopic rod 8. The auxiliary electromagnet 9 is used to establish a connection between the telescopic rod 8 and the auxiliary plate 7.

[0045] The outer periphery of the auxiliary plate 7 is recessed to form several slots 10. Several guide rails 11 are arranged on the lower inner side of the vacuum feeding barrel 1. The guide rails 11 and the slots 10 are arranged opposite to each other. When the auxiliary plate 7 is engaged with the guide rails 11, the auxiliary plate 7 divides the interior of the vacuum feeding barrel 1 into an upper cavity and a lower cavity. The upper cavity is directly connected to the argon gas source, while the lower cavity contains Sc.

[0046] A limit block is provided at the lower end of the guide rail 11 to prevent the auxiliary plate 7 from coming off the lower end of the guide rail 11.

[0047] The drive rod 6 includes a fixed section and a moving section. The fixed section is connected to the drive motor 4, and the moving section is connected to the feed plug 5. The fixed section is equipped with a drive electromagnet 12, and the upper end of the moving section is equipped with a connecting magnet. The moving section is slidably connected to the fixed section. When the drive electromagnet 12 is energized, it can push the fixed section to move along the axis of the drive rod 6, so that the feed plug 5 moves into or out of the vacuum feeding barrel 1.

[0048] In this embodiment, the vacuum melting furnace can be a 25kg, 50kg, 100kg, or 200kg class vacuum induction melting furnace. Alternatively, a VIM-25, VIM-50, VIM-100, or equivalent vacuum induction melting device can be selected based on the weight of the hot-end components. The furnace body feeding port of the vacuum melting furnace is connected to the vacuum feeding tank 1 via a water-cooled flange, metal gasket, or graphite gasket, allowing the vacuum feeding tank 1 to add Sc material without disrupting the vacuum environment inside the furnace.

[0049] The vacuum feeding tank 1 is a cylindrical, sealed stainless steel chamber made of 316L or 304 stainless steel. The inner surface roughness Ra is no greater than 1.6 μm. The inner diameter of the tank is 80–300 mm, the height is 200–800 mm, and the wall thickness is 2–8 mm. A water-cooled jacket or heat insulation jacket can be installed near the lower part of the vacuum melting furnace. The cooling water flow rate in the water-cooled jacket is 1–5 L / min to reduce heat radiation to the seals and electromagnetic components.

[0050] Feed pipe 2 is used to connect to an external quantitative feeder, weighing hopper, or manual feeding bin. The connection between feed pipe 2 and vacuum feeding tank 1 is inclined downwards at 30° to 60°, allowing the Sc material to enter the vacuum feeding tank 1 by its own weight. The feed valve on feed pipe 2 can be a KF vacuum ball valve, vacuum slide gate valve, or needle valve, with a nominal diameter of DN10 to DN40. Feed pipe 2 can also be connected to an argon bypass with a flow rate of 0.5 to 5 L / min, used to purge feed pipe 2 before and after feeding.

[0051] Gas connection port 3 connects to the vacuum pump, vent pipe, and argon source. The vacuum pump can be a 2XZ series rotary vane vacuum pump, or a vacuum pump unit consisting of a ZJ series Roots pump and a rotary vane pump; for higher cleanliness requirements, a molecular pump unit can also be used. After evacuating the vacuum feeding tank 1 to a vacuum level not exceeding 0.1 Pa, argon gas with a purity of not less than 99.99%, preferably not less than 99.999%, is introduced for replacement. The replacement is performed 1 to 3 times, ultimately ensuring that the oxygen content inside the tank does not exceed 100 ppm.

[0052] The drive motor 4 is a servo motor, stepper motor, or frequency converter motor, preferably an external servo motor with a vacuum isolation structure. The rated power of the motor is 0.05 to 0.75 kW, and the output speed is 30 to 600 r / min. The drive motor 4 is connected to the drive rod 6 via a magnetohydrodynamic sealed transmission component, a mechanical seal component, or a coupling located outside the vacuum feeding tank 1 to ensure that the vacuum feeding tank 1 remains sealed when the drive rod 6 rotates.

[0053] The feed plug 5 is a frustum-shaped or conical plug body coaxially arranged with the vacuum feeding tank 1, and its upper surface tapers downward to form a conical surface of 15° to 60°. The outer periphery of the feed plug 5 mates with the inner wall of the vacuum feeding tank 1 to form a temporary sealing surface, with a sealing gap of 0.02 to 0.50 mm. The feed plug 5 can be made of molybdenum alloy, tungsten alloy, high-purity graphite, alumina ceramic, or heat-resistant metal with a surface coated with zirconia ceramic. A graphite sealing ring or a metal elastic sealing ring is provided on the side of the feed plug 5.

[0054] The extension stroke of the drive rod 6 is 50-300mm, the extension speed is 50-500mm / s, and the retraction speed is 20-300mm / s; the working voltage of the drive electromagnet 12 is 24V or 48V, and the attraction force or thrust is 50-300N, so that the feed plug 5 can move from the sealed position to the feeding position in a short time.

[0055] The auxiliary plate 7 is a disc-shaped piston structure, with a sealing element on its outer periphery that mates with the inner wall of the vacuum feeding tank 1. The sealing element can be a graphite sealing ring, a metal C-shaped sealing ring, or a high-temperature resistant fluororubber sealing ring. The main body of the auxiliary plate 7 is made of 316L stainless steel, nickel-based alloy, or ceramic composite material, with a thickness of 5–30 mm. After the auxiliary plate 7 is arranged coaxially with the vacuum feeding tank 1, a pressurization zone that can accommodate Sc material and argon gas can be formed on its lower side.

[0056] The telescopic rod 8 can be a cylinder, an electric push rod, or a linear module, with a stroke of 50–300 mm and a thrust of 50–500 N. An auxiliary electromagnet 9 is located at the lower end of the telescopic rod 8, operating at 24V or 48V, with a pull-in force of 20–200 N. It is used to temporarily connect with the auxiliary plate 7 when it is reset, and to disconnect after the auxiliary plate 7 enters the guide rail 11.

[0057] The slot 10 is located on the outer periphery of the auxiliary plate 7, and the guide rail 11 is located on the lower inner wall of the vacuum feeding barrel 1. The slot 10 and the guide rail 11 correspond one-to-one. The guide rail 11 can be made of 316L stainless steel or nickel-based alloy strips, with a quantity of 2 to 6, a width of 3 to 15 mm, and a height of 20 to 120 mm. It is used to restrict the circumferential rotation of the auxiliary plate 7 and guide the auxiliary plate 7 to move axially.

[0058] In practical use, the device first uses a vacuum pump to evacuate the vacuum feeding tank 1 to make the inside of the vacuum feeding tank 1 a near-vacuum state, and then turns on the argon source to input argon into the vacuum feeding tank 1. The material is fed into the vacuum feeding tank 1 through the feed pipe 2, and the feeding amount is adjusted according to the actual usage requirements. After Sc is added into the vacuum feeding tank 1, it falls directly onto the upper surface of the feed plug 5. To improve the feeding effect and prevent Sc from being oxidized, the feed pipe 2 can also be connected to an argon source. At this time, the auxiliary plate 7 is located on the upper side of the connection between the feed pipe 2 and the vacuum feeding barrel 1. The upper and lower spaces of the auxiliary plate 7 are connected, that is, the air pressure on the upper side and the air pressure on the lower side of the auxiliary plate 7 are equal. The drive motor 4 drives the drive rod 6 and the feed plug 5 to rotate, so that the Sc powder is evenly dispersed on the outer edge of the upper surface of the feed plug 5 under the action of centrifugal force. The auxiliary plate 7 is pushed downward by the telescopic rod 8 until the guide rail 11 is inserted into the slot 10. A limiting guide is formed between the auxiliary plate 7 and the inner wall of the vacuum feeding barrel 1. At this time, the argon gas is introduced, so that the auxiliary plate 7 moves downward under the action of gas pressure. The auxiliary plate 7 compresses the argon gas on the lower side under the action of gas pressure until the auxiliary plate 7 stops moving and a high pressure argon gas is formed in the pressurization zone. When the driving electromagnet 12 is energized, the feed plug 5 is pushed down rapidly by magnetic force. The outer edge of the upper surface of the feed plug 5 is exposed to the inside of the vacuum melting furnace, and the Sc powder is blown out rapidly under the action of argon gas, thus completing the feeding. Argon gas is stopped flowing into the vacuum feeding tank 1. At the same time, the vacuum pump operates to evacuate the inside of the vacuum feeding tank 1, causing the auxiliary plate 7 to reset under negative pressure until the auxiliary plate 7 separates from the guide rail 11. The auxiliary electromagnet 9 is energized, causing the telescopic rod 8 to re-establish a connection with the auxiliary plate 7. The telescopic rod 8 drives the auxiliary plate 7 to move upward, so that the feed pipe 2 is connected to the lower part of the vacuum feeding tank 1. The electromagnet 12 is driven to reverse the current to magnetically attract the moving section, causing the feed plug 5 to reset and wait for the next feeding.

[0059] During the above operation, when the drive motor 4 drives the feed plug 5 to rotate, the Sc material migrates to the outer edge of the feed plug 5 under the combined action of centrifugal force and the conical surface, avoiding the accumulation of Sc material in the center position. When the feed plug 5 moves down, the Sc material at the outer edge is preferentially exposed to the inside of the vacuum melting furnace. The argon gas in the pressurization zone is ejected along the annular channel formed between the outer edge of the feed plug 5 and the inner wall of the barrel, thereby carrying the Sc material in a dispersed state above the alloy melt.

[0060] Before adding Sc material, the temperature of the alloy melt is controlled at 1400-1480℃, and the vacuum degree in the vacuum melting furnace is maintained at 0.1-0.5Pa or under an argon protective atmosphere; the feeding plug 5 rotates for 1-3 seconds, and the rotation speed is 60-300 r / min; after the auxiliary plate 7 moves down to increase the pressure, the gauge pressure in the pressure-increasing zone is 0.01-0.15MPa, the blowing time is 0.2-2.0s, and the volume of argon gas injected in a single injection is 0.02-2L.

[0061] After the Sc material is added, electromagnetic or mechanical stirring in the vacuum melting furnace continues for 2-3 minutes to ensure uniform diffusion of Sc in the alloy melt; then casting is carried out within 5-10 minutes. By using the above-mentioned low-oxygen, short-duration, and dispersed blowing feeding method, the probability of Sc oxidation and burning or local enrichment near the feeding port can be reduced, and the risk of introducing impurities such as O, S, and P due to disruption of the furnace vacuum can be reduced.

[0062] The preparation apparatus of this application forms an inert gas protection feed during the Sc feeding process, providing inert gas protection throughout the process and significantly reducing the probability of Sc reacting with residual oxygen to form Sc2O3.

[0063] Meanwhile, the feed is delivered through the retractable and rotatable feed plug 5, which makes the Sc feed in a circular distribution, forming a multi-point and uniform material distribution, greatly shortening the homogenization time of Sc, reducing the chance of Sc contacting the inner wall of the vacuum melting furnace, and further reducing burn-off.

[0064] The models and parameters in this embodiment are preferred ranges. Under the conditions of vacuum sealing, inert gas protection, quantitative dispersion of Sc addition, and connection with the vacuum induction melting furnace, equivalent substitutions can be made according to the alloy melting amount, Sc addition amount, and vacuum melting furnace specifications.

[0065] The above-described specific embodiments are merely specific examples of the present invention. The patent protection scope of the present invention includes, but is not limited to, the product forms and styles of the above-described specific embodiments. Any nickel-based cast high-temperature alloy, preparation method and hot end component that improves creep resistance and lifespan according to the claims of the present invention, and any appropriate changes or modifications made thereto by those skilled in the art, shall fall within the patent protection scope of the present invention.

Claims

1. A nickel-based cast superalloy for improving creep resistance and lifespan, characterized in that, The nickel-based casting superalloy is obtained by microalloying M247 type nickel-based casting superalloy with Sc, and includes the following components by mass percentage: C 0.14-0.20%, Cr 8.0-9.0%, Co 9.0-11.0%, Al 5.3-5.7%, Ti 0.5-1.5%, Ta 2.8-3.3%, W 9.5-10.5%, Mo 0.4-0.8%, Hf 1.2-1.6%, B 0.01-0.02%, Zr 0.02-0.08%, Sc 0.001-0.2%, with the balance being Ni and impurities. The nickel-based casting superalloy forms an Al-Ti composite precipitate strengthening phase containing Sc, and satisfies 6.55 ≤ Al + Ti + Mo ≤ 7.75 and 6.15% ≤ Al + Sc + Ti ≤ 7.15%, where Al, Ti, Mo and Sc represent the mass percentage content of the corresponding elements.

2. The nickel-based cast superalloy for improving creep resistance and service life according to claim 1, characterized in that, The mass percentage of the impurities is not higher than 0.015% for S, 0.15% for Si, 0.15% for Mn, and 0.35% for Fe.

3. The nickel-based cast superalloy for improving creep resistance and service life according to claim 1, characterized in that, The nickel-based cast superalloy has a creep rupture life of not less than 225 hours under 870℃ / 390MPa conditions, and / or a creep rupture life of not less than 77 hours under 980℃ / 220MPa conditions.

4. The method for preparing a nickel-based cast superalloy with improved creep resistance and lifespan according to claim 1, characterized in that, Specifically, the process includes the following steps: vacuum induction melting and refining according to the target composition to obtain an alloy melt; adding Sc to the alloy melt after refining and before casting; precision casting the alloy melt after adding Sc, and performing solution treatment and aging treatment on the casting to obtain the nickel-based casting high-temperature alloy.

5. The method for preparing nickel-based cast superalloys according to claim 4, characterized in that, The Sc is added in the form of pure Sc, Ni-Sc master alloy or Sc-containing alloy additive; the Sc is added 5 to 10 minutes before casting, the temperature of the alloy melt is not higher than 1480℃ when Sc is added, and the mixture is stirred for 2 to 3 minutes after adding Sc.

6. The method for preparing nickel-based cast superalloys according to claim 4, characterized in that, The vacuum induction melting is performed with a vacuum degree not exceeding 0.1 Pa and a melting temperature of 1520–1550 °C; the refining is performed under a vacuum degree of 0.1–0.5 Pa for 30–40 minutes; the precision casting is performed by pouring the alloy melt into a ceramic mold shell with a preheating temperature of 850–1000 °C.

7. The method for preparing nickel-based cast superalloys according to claim 4, characterized in that, The solution treatment and aging treatment include the following steps performed sequentially: solution treatment at 1210℃±10℃ for 2 hours followed by air cooling to room temperature; first-level aging treatment at 870℃±10℃ for 16 hours followed by air cooling to room temperature; and second-level aging treatment at 760℃±10℃ for 16 hours followed by air cooling to room temperature.

8. A hot-end component, characterized in that, The hot-end component comprises the nickel-based cast high-temperature alloy according to any one of claims 1 to 3, wherein the nickel-based cast high-temperature alloy is prepared by the preparation method according to any one of claims 4 to 7.

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