Nickel-based alloy dual-performance hollow turbine disc, preparation method thereof and hollow turbine disc forging die

Abstract

The invention relates to the field of plastic forming hot working, in particular to a nickel-based alloy dual-performance hollow turbine disc, a preparation method thereof and a hollow turbine disc forging die. According to the preparation method provided by the invention, the forming controllability of the dual-performance turbine disc is realized by adopting a set of tool mold with a cooling system, and in the forging forming process, local deformation and pressure maintaining of a disc hub of the turbine disc are ingeniously combined with a gradual change controlled cooling solid solution heat treatment technology for different parts; and a disc hub fine grain structure and a fine spherical gamma'precipitated phase, a disc edge coarse grain structure and a large-size blocky gamma 'precipitated phase, and a medium-size grain structure and a gamma' precipitated phase in a center plate transition area are obtained. In the process of the forming method, through reasonable matching of deformation of different areas of the disc hub and the disc edge and gradient cooling, gradient heat treatment does not need to be conducted in a special heat treatment tool after the turbine disc is formed, the production efficiency is improved, the production cost is reduced, and good economic benefits are achieved.

Description

Technical Field

[0001] The invention relates to the field of plastic forming hot processing, in particular to a nickel-based alloy dual-performance hollow turbine disc and a preparation method thereof and a hollow turbine disc forging die. Background Art

[0002] The turbine disk is a key hot end component of an aircraft engine. Under working conditions, the operating temperature of the entire disk gradually decreases from the disk edge to the disk hub along the diameter direction. The working conditions put forward tailoring performance requirements for the disk: the disk edge is connected to the blade, and the operating temperature is high due to the friction of the airflow, but the stress is small, so the material is required to have high creep performance and fracture toughness; the disk hub is connected to the shaft, and the operating temperature is relatively low, but it is subjected to the large centrifugal force brought by the rotation of the disk, so the material is required to have high strength, plasticity and low-cycle fatigue strength.

[0003] Early dual-performance discs were made of dissimilar alloy materials, that is, a high-strength alloy was used for the disc hub, and another creep-resistant alloy was used for the disc rim. The two alloys were combined by a connection method (such as welding, hot isostatic pressing, etc.). This connection method has problems such as poor material weldability, difficult to control joint defects, and unsatisfactory microstructure. The connection interface of the disc is the weakest link in the disc body, which seriously restricts the development and application of the disc. At present, the use of an alloy to prepare a dual-structure / dual-performance disc with different microstructures in the disc hub and disc rim has become a hot topic of concern. That is, a fine-grained structure is obtained in the disc hub to ensure high strength, and a coarse-grained structure is obtained in the disc rim to ensure good durability and creep performance. The transition area (width plate position) between the disc hub and the disc rim requires a smooth transition of the grain structure. This disc avoids the potential safety hazards caused by the connection between dissimilar metals, fully meets the working conditions of high thrust-to-weight ratio engines, and significantly improves the safety factor of the entire disc.

[0004] For dual-performance high-temperature alloy turbine disks, obtaining dual-performance disks with a single alloy structure mainly includes two processes: ultrafine-grained high-strength billet preparation and gradient heat treatment. First, ultrafine-grained billets are used to prepare forging blanks, and then the forging blanks are subjected to gradient heat treatment. That is, the fine-grained billet is subjected to gradient heat treatment to make the grains of the disk edge grow and obtain a coarse-grained structure to meet the durability, creep and crack growth resistance. Studies have shown that in terms of microstructure, the dual-performance disks of nickel-based high-temperature alloys are not only reflected in the difference in grain size, but also in the size and morphology of the γ' phase. That is, the mechanical properties of the dual-performance disk are not only related to the grain size, but also have an important relationship with the size and morphology of the γ' phase. To meet the dual-performance requirements of the disk hub and the disk edge at the same time, this is a big challenge for hot processing technology. Summary of the invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a nickel-based alloy dual-performance hollow turbine disk, a preparation method thereof and a hollow turbine disk forging die. The preparation method provided by the present invention can prepare a dual-performance hollow turbine disk that meets both the disk hub and the disk rim. It not only has high mechanical properties, but can also be prepared in a set of tooling dies. After forming, there is no need for gradient heat treatment in special heat treatment tooling, which improves production efficiency, reduces production costs, and has good economic benefits.

[0006] The present invention provides a method for preparing a nickel-based alloy dual-performance hollow turbine disk, comprising the following steps:

[0007] S1) performing large deformation closed final forging in a die on a turbine disk blank whose disk hub thickness is greater than the disk rim thickness to obtain a turbine disk forging blank; the deformation amount of the large deformation closed final forging is the difference between the disk hub thickness and the disk rim thickness of the turbine disk blank;

[0008] S2) The turbine disk forging blank obtained in step S1) is cooled with decreasing cooling effect from the disk hub to the disk edge, and then heat treated to obtain a nickel-based alloy dual-performance hollow turbine disk.

[0009] The preparation method of the nickel-based alloy dual-performance hollow turbine disk provided by the present invention is suitable for turbine disks whose blanks are made of nickel-based alloys, and is specifically suitable for sub-solution heat-treated nickel-based alloys whose solid solution heat treatment temperature is lower than the temperature at which the strengthening phase is completely dissolved back, so as to prevent the internal structure of the turbine disk, especially the grain structure of the hub part, from being seriously coarsened. In some embodiments of the present invention, the nickel-based alloy is GH4151 nickel-based alloy, and its element composition includes: C, Co, Cr, W, Mo, Al, Ti, Nb and Ni, etc.

[0010] The inventors of the present application creatively discovered that during the forging process of a dual-performance hollow turbine disk, by reasonably matching the deformation amounts of different areas of the disk hub and the disk rim and gradient cooling, a dual-performance hollow turbine disk that meets the requirements of both the disk hub and the disk rim can be prepared, has high mechanical properties, and does not require subsequent gradient heat treatment.

[0011] The present invention first performs a large deformation closed final forging in a mold on a turbine disk blank whose hub thickness is greater than the disk rim thickness to obtain a turbine disk forging blank. The turbine disk blank described in the present invention is a "gyro-shaped" turbine disk prefabricated blank, whose hub thickness is greater than the disk rim thickness, and presents a shape that is thick in the middle and thin at the edge. The turbine disk blank whose hub thickness is greater than the disk rim thickness described in the present invention is also provided with a center hole at the hub position. The difference between the hub thickness and the disk rim thickness of the turbine disk blank described in the present invention is 50-80% of the hub thickness of the turbine disk blank. In certain embodiments of the present invention, the hub thickness of the turbine disk blank whose hub thickness is greater than the disk rim thickness is 140-160 mm, and the disk rim thickness is 30-50 mm.

[0012] In certain embodiments of the present invention, the turbine disk blank with a hub thickness greater than the disk rim thickness is prepared by the following method: high-temperature alloy rods are cut according to the shape and volume of the turbine disk forging to be prepared, a cylindrical turbine disk preform is prepared by an isothermal forging method, and then the cylindrical turbine disk preform is further processed into a turbine disk blank with a hub thickness greater than the disk rim thickness; wherein the average grain size of the selected high-temperature alloy rod structure is level 6~7.

[0013] Before the turbine disk blank is subjected to large deformation closed final forging, the present invention includes heating the turbine disk blank, and the heating temperature is consistent with the solution heat treatment temperature of the same grade of alloy. In the present invention, the turbine disk blank is heated to 750-850°C for insulation, heated to 900-1000°C for insulation, and heated to the final forging heating temperature for insulation. The final forging heating temperature is 30°C-80°C below the complete dissolution temperature of the γ' strengthening phase of the nickel-based alloy. The final forging heating temperature in the present invention is 1100-1150°C; the heating rate is 50-200°C / h; the insulation time is 1-2 min / mm based on the hub thickness of the turbine disk blank.

[0014] When the present invention performs the large deformation closed final forging on the turbine disc blank, the deformation of the large deformation closed final forging is the difference between the hub thickness and the rim thickness of the turbine disc blank. The present invention performs large deformation closed final forging on the turbine disc blank in a mold, and the mold includes an upper mold insert and a lower mold insert. In certain embodiments of the present invention, the turbine disc blank is placed in the lower mold insert of the mold to ensure that the turbine disc blank and the lower mold insert of the mold are coaxial, and then the turbine disc blank is subjected to large deformation closed final forging in the axial direction. The pressing speed of the large deformation closed final forging of the present invention is 0.01~10 mm / s. The method of the present invention obtains a fine-grained structure by deforming the hub part with a large deformation, so it is not necessary to use multiple fires with large deformation to prepare ultrafine-grained rods, thereby reducing the number of forming fires.

[0015] When the present invention performs large deformation closed final forging on the turbine disk blank, the forging method adopted is isothermal forging, that is, the mold temperature is consistent with the forging heating temperature of the turbine disk blank. When the present invention performs large deformation closed final forging on the turbine disk blank, it is also necessary to spray lubricant, and the sprayed lubricant is a graphite lubricant with good thermal conductivity to prevent affecting the heat transfer of the upper and lower die cooling systems to the turbine disk forging after the final forging is completed, thereby affecting the cooling effect.

[0016] After the turbine disk blank is subjected to large deformation closed final forging, the present invention further includes holding pressure for 5 to 30 minutes. During the holding pressure process, the temperature of the isothermal forging die remains unchanged, which promotes sufficient static recrystallization of the alloy, facilitates more strengthening phases to dissolve back into the matrix, and facilitates the precipitation of strengthening phases of different sizes and morphologies during the subsequent cooling process.

[0017] After the present invention performs large deformation closed final forging on the turbine disk blank to obtain the turbine disk forging blank, the obtained turbine disk forging blank is cooled with a decreasing cooling effect from the disk hub to the disk edge. Specifically, the obtained turbine disk forging blank is cooled with a decreasing cooling effect from the disk hub to the web plate and then to the disk edge. More specifically, the obtained turbine disk forging blank is cooled with a decreasing cooling effect from the disk hub to the web plate and then to the disk edge. When cooling the obtained turbine disk forging blank, the cooling effect on the disk hub is greater than the cooling effect on the web plate, and the cooling effect on the web plate is greater than the cooling effect on the disk edge. In certain embodiments of the present invention, a spiral cooling pipe is used to cool the turbine disk forging blank with a decreasing cooling effect from the disk hub to the disk edge through a cooling medium; the number of turns of the spiral cooling pipe is more than 3, and the pipe thickness of the spiral cooling pipe increases by 5 to 15 mm per turn from the center to the edge. In certain embodiments of the present invention, the number of turns of the vortex-shaped cooling pipe is 3 turns, and the pipe thickness of the vortex-shaped cooling pipe is 25~35 mm, 35~45 mm and 45~55 mm from the core to the edge. The cooling medium of the present invention is water, and the cooling effect is controlled by the water flow rate, and the water flow rate V=1 mm / s~15 mm / s. In the present invention, the pipe thickness distribution of each turn of the vortex-shaped cooling pipe gradually increases from the core to the outer edge, so the cooling pipes are arranged more closely in the core than at the edge, and the heat taken away per unit area of ​​the more closely arranged core is more, and the cooling rate is faster than that of the outer edge area, so as to achieve the effect of gradient cooling of the turbine disc forging blank with decreasing cooling effect from the core to the edge. In the present invention, the gradient cooling can be stopped after the edge portion of the turbine disc forging blank is cooled to below 800°C.

[0018] The present invention cools the obtained turbine disk forging blank with a cooling effect decreasing from the disk hub to the disk edge, and then performs heat treatment to obtain a nickel-based alloy dual-performance hollow turbine disk. The present invention does not need to perform a gradient heat treatment from the disk hub to the disk edge of the turbine disk forging blank, and only needs to perform conventional stabilization or aging heat treatment of such alloy forgings to obtain a nickel-based alloy dual-performance hollow turbine disk.

[0019] The present invention provides a nickel-based alloy dual-performance hollow turbine disk obtained by applying any of the above-mentioned preparation methods. The nickel-based alloy dual-performance hollow turbine disk provided by the present invention has a fine-grained structure and fine spherical γ' precipitation phase at the hub, a coarse-grained structure and large-sized blocky γ' precipitation phase at the rim, and a medium-sized grain structure and γ' precipitation phase in the web-plate transition region. It is a dual-performance turbine disk that satisfies both the hub and the rim, and has high mechanical properties.

[0020] The present invention also provides a hollow turbine disk forging die, comprising: an upper die and a lower die; both the upper die and the lower die are provided with a vortex-shaped cooling channel vortexing from the core to the edge of the hollow turbine disk forging die.

[0021] The number of turns of the vortex cooling pipe of the present invention is more than 3 turns, and the pipe thickness of the vortex cooling pipe increases by 5 to 15 mm per turn from the core to the edge. In certain embodiments of the present invention, the number of turns of the vortex cooling pipe is 3 turns, and the pipe thickness of the vortex cooling pipe is 25 to 35 mm, 35 to 45 mm and 45 to 55 mm per turn from the core to the edge. The present invention limits the pipe thickness of the vortex cooling pipe to increase from the core to the edge per turn, so that the cooling pipes arranged in the hollow turbine disc forging die are arranged more closely in the core than at the edge, and the heat taken away per unit area of ​​the more closely arranged core is more, and the cooling rate is faster than that of the outer edge area, so as to achieve the effect of gradient cooling of the turbine disc forging blank with decreasing cooling effect from the core to the edge. The distribution form of the vortex cooling pipes arranged in the upper die and the lower die of the hollow turbine disc forging die of the present invention is consistent, and is distributed circumferentially in a counterclockwise or clockwise direction, which helps the hollow turbine disc forging blank to obtain a uniform cooling effect.

[0022] The core of the spiral cooling pipe of the present invention is provided with a cooling medium inlet, and the edge of the pipe is provided with a cooling medium outlet, so that the cooling medium can sequentially cool the core and edge of the hollow turbine disk forging die. The inlets of the upper die cooling pipe and the lower die cooling pipe of the hollow turbine disk forging die of the present invention are both provided at the core of the die, and the outlets are both provided at the outer edge of the die. Therefore, after flowing through the heated die, the temperature of the cooling medium at the outlet is higher than the temperature of the cooling medium at the inlet, which is beneficial for the core of the turbine disk to obtain a faster cooling effect than the outer edge area, thereby constructing a cooling system in which the cooling effect gradually decreases from the core of the hub to the edge of the disk.

[0023] The core position of the lower die of the hollow turbine disk forging die described in the present invention is also provided with an axial cooling duct that specifically passes through the center hole of the hollow turbine disk forging blank, thereby ensuring that the hub of the turbine disk obtains a faster cooling effect during the solution heat treatment process after the final forging is completed, and establishing a cooling gradient in which the cooling speed decreases successively from the hub to the edge of the disk, thereby ensuring that strengthening phases of different morphologies and sizes are precipitated in different areas of the disk.

[0024] The present invention provides a nickel-based alloy dual-performance hollow turbine disk and a preparation method thereof and a hollow turbine disk forging die. The preparation method provided by the present invention realizes the controllability of the dual-performance turbine disk forming by adopting a set of tooling dies with a cooling system. In the forging forming process, the local deformation of the turbine disk hub, pressure maintenance and gradient controlled cooling solid solution heat treatment technology for different parts are cleverly combined to obtain a fine-grained structure with an average grain size of 10 to 12 and fine spherical γ' precipitation phases at the hub, a coarse-grained structure with an average grain size of 6 to 7 and large-sized blocky γ' precipitation phases at the rim, and a medium-sized grain structure and γ' precipitation phases in the transition area of ​​the web. In the forming method of the present invention, by reasonably matching the deformation amount and gradient cooling of different areas of the hub and rim, the turbine disk does not need to be subjected to gradient heat treatment in a special heat treatment tooling after forming, thereby improving production efficiency, reducing production costs, and having good economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the structure of the hollow turbine disk prefabricated cake blank in Example 1 of the method of the present invention;

[0026] Figure 2 It is a schematic diagram of the structure of the upper mold cooling pipeline distribution in Example 1 of the method of the present invention;

[0027] Figure 3 This is a schematic diagram of the structure of the lower mold cooling pipeline distribution in Example 1 of the method of the present invention;

[0028] Figure 4 Schematic diagram of the initial state of final forging deformation in Example 1 of the method of the present invention;

[0029] Figure 5 Schematic diagram of the final state of final forging deformation in Example 1 of the method of the present invention;

[0030] Figure 6 This is a grain microstructure diagram of a GH4151 alloy turbine disk forging blank hub according to Example 1 of the present invention;

[0031] Figure 7 This is a grain microstructure diagram of the web-to-plate transition zone of the GH4151 alloy turbine disk forging blank according to Example 1 of the present invention;

[0032] Figure 8 This is a grain microstructure diagram of the disk edge of the GH4151 alloy turbine disk forging blank of Example 1 of the present invention;

[0033] Fig. 9 This is a microstructure diagram of the precipitation phase morphology of the hub of the GH4151 alloy turbine disk forging blank of Example 1 of the present invention;

[0034] Fig.10 This is a microstructure diagram of the precipitation phase morphology in the transition zone between the blank and the plate of the GH4151 alloy turbine disk forging according to Example 1 of the present invention;

[0035] Fig.11 This is a microstructure diagram of the precipitation phase morphology of the disk edge of the GH4151 alloy turbine disk forging blank of Example 1 of the present invention. DETAILED DESCRIPTION

[0036] The present invention discloses a nickel-based alloy dual-performance hollow turbine disk, a preparation method thereof, and a hollow turbine disk forging die. Those skilled in the art can refer to the content of this article and appropriately improve the process parameters to achieve it. It is particularly important to point out that all similar substitutions and modifications are obvious to those skilled in the art, and they are all deemed to be included in the present invention. The method and application of the present invention have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the method and application of this article without departing from the content, spirit and scope of the present invention to realize and apply the technology of the present invention.

[0037] The present invention will be further described below in conjunction with embodiments:

[0038] Example 1

[0039] Step 1: Forging prefabricated cake (1)

[0040] According to the shape and volume of the hollow turbine disk forging blank to be prepared, the GH4151 high-temperature alloy bar is cut into pieces. The blank size is Φ120 mm×300 mm. The average grain size of the initial structure of the bar blank is grade 6. The heating temperature of the blank and the mold is 1110°C. The turbine disk prefabricated cake (1) is prepared by the isothermal forging method. Figure 1 As shown, Figure 1 This is a schematic diagram of the structure of the hollow turbine disk prefabricated cake in Example 1 of the method of the present invention.

[0041] Step 2: Processing hollow prefabricated blank (26)

[0042] Combined with the final forging process, the prefabricated cake blank is processed into a "gyro shape" with a hub thickness G1 of 150 mm and a rim thickness G2 of 40 mm, and a center hole is processed at the hub position to obtain a hollow prefabricated blank (26);

[0043] Step 3: Prepare forging die

[0044] The cooling system of the final forging die is formed by machining an upper die cooling channel (23) and a lower die cooling channel (27) between the upper die (21) and the upper die insert (22), and between the lower die (28) and the lower die insert (29), respectively. The cooling channel spacings are D1=30 mm, D2=40 mm, and D3=50 mm, and the cooling channels are distributed in a clockwise direction; Figure 2~Figure 3 As shown, Figure 2 Schematic diagram of the structure of the upper mold cooling pipeline distribution in Example 1 of the method of the present invention, Figure 3 This is a schematic diagram of the structure of the lower mold cooling pipeline distribution in Example 1 of the method of the present invention.

[0045] Step 4: Heating the hollow prefabricated blank (26)

[0046] The hollow prefabricated blank (26) is placed in a heating furnace with a furnace temperature lower than 300°C for step heating. The step heating method is firstly to increase the temperature to 800°C at a heating rate of 100°C / h and keep the temperature for 3 hours. After the heat preservation, the temperature is increased to 950°C at a heating rate of 100°C / h and kept the temperature for 3 hours. After the heat preservation, the temperature is increased to a final forging temperature of 1120°C at a heating rate of 60°C / h for heating and heat preservation. The heat preservation time of each stage is calculated according to Formula 1.

[0047] T=150 mm×1.2 min / mm=180 min Formula 1;

[0048] Wherein, T is the heat preservation time of the hollow turbine disk preform blank (26); G2 is the initial thickness of the hub of the hollow turbine disk preform blank (26).

[0049] Step 5: Perform large deformation closed final forging on the hollow prefabricated blank (26)

[0050] The heated hollow preformed blank (26) is sprayed with graphite lubricant and then quickly transferred to the lower die (28) to ensure that the hollow preformed blank (26) and the lower die (28) are coaxial, and the hollow preformed blank (26) is final forged along the axial direction, with a pressing deformation of 110 mm and a pressing speed of 0.5 mm / s. A turbine disk forging blank (30) is obtained; Figure 4~Figure 5 As shown, Figure 4 Schematic diagram of the initial state of final forging deformation in Example 1 of the method of the present invention, Figure 4 Among them, 21-upper die insert, 22-upper die, 23-upper die cooling pipe, 24 thermal insulation gasket, 25-upper die sleeve, 26-prefabricated blank, 27-lower die cooling pipe, 28-lower die, 29-lower die insert, 210-lower die sleeve; Figure 5 Schematic diagram of the final state of final forging deformation in Example 1 of the method of the present invention, Figure 5 In the middle, 30-double performance turbine disc blank, made of Figure 4The 26-prefabricated blank is obtained after large deformation closed final forging.

[0051] Step 6: Maintaining the pressure of the hollow turbine disk forging blank (30)

[0052] After the final forging is completed, the turbine disk forging blank (30) is pressure-maintained by the upper die (21) and the upper die insert (22), the lower die (28) and the lower die insert (29), and the pressure-maintaining time is 10 minutes;

[0053] Step 7: Gradient cooling of the hollow turbine disk forging blank (30)

[0054] After the pressure holding is completed, the upper die (21) and the upper die insert (22), the lower die (28) and the lower die insert (29) and the hollow turbine disk forging blank (30) are quickly taken out from the die heating furnace, and the upper die cooling channel (23) and the lower die cooling channel (27) are connected to cooling water, and the cooling water flow rate V=5 mm / s, and the disk hub, the web and the disk edge of the hollow turbine disk forging blank (30) are gradient cooled. After the disk edge of the hollow turbine disk forging blank (30) is cooled to below 800°C, it is taken out from the die and air-cooled;

[0055] Step 8: Heat treatment of the hollow turbine disk forging blank (30)

[0056] The cooled GH4151 high-temperature alloy hollow turbine disk forging blank was subjected to 850°C insulation for 8 hours / air cooling+760°C insulation for 16 hours / air cooling treatment.

[0057] Comparative Example 1

[0058] The hollow preformed blank (26) prepared by the same method as in Example 1 is subjected to small deformation final forging in step five, that is, the hot hollow preformed blank (26) is sprayed with graphite lubricant and quickly transferred to the lower die (28), ensuring that the hollow preformed blank (26) and the lower die (28) are coaxial, and the hollow preformed blank (26) is final forged along the axial direction, with a downward deformation of 30 mm (deformation 20%) and a downward speed of 0.5 mm / s, to obtain a turbine disk forging blank (30). The subsequent treatment of the turbine disk forging blank is consistent with steps 6 to 8 in the embodiment.

[0059] Comparative Example 2

[0060] The hollow turbine disk forging blank (30) prepared by the same method as in Example 1 is uniformly cooled in step seven, that is, the gradient cooling system innovatively designed in the method of the present invention is not used, but the hollow turbine disk forging blank (30) is uniformly cooled by using cooling pipes uniformly arranged in the mold structure, and after the temperature of the disk edge portion of the hollow turbine disk forging blank (30) drops below 800° C., it is taken out of the mold and air-cooled. The subsequent treatment of the turbine disk forging blank is consistent with step eight in the embodiment.

[0061] Through the tests in the above-mentioned Example 1 and Comparative Examples 1 and 2, the room temperature tensile mechanical properties of the nickel-based deformed high-temperature alloy turbine disk obtained are shown in Table 1:

[0062] Table 1

[0063]

[0064] As can be seen from Table 1, compared with the small deformation final forging used in Comparative Example 1 and the traditional uniform cooling system used in Comparative Example 2, the nickel-based high-temperature alloy using Example 1 of the method of the present invention simultaneously obtains better room temperature tensile strength and high temperature endurance life, which are significantly better than the comparative examples. Figure 6~Figure 8 The grain microstructure diagram of the GH4151 alloy turbine disk forging blank of Example 1 of the present invention is shown, wherein Figure 6 This is a grain microstructure diagram of the hub of the GH4151 alloy turbine disk forging blank of Example 1 of the present invention. Figure 7 This is a grain microstructure diagram of the transition zone between the blank and the plate of the GH4151 alloy turbine disk forging according to Example 1 of the present invention. Figure 8 This is a grain microstructure diagram of the disk rim of the GH4151 alloy turbine disk forging blank of Example 1 of the present invention. Figure 9~Figure 11 The microstructure diagram of the precipitation phase morphology of the GH4151 alloy turbine disk forging blank of Example 1 of the present invention is shown, wherein Fig. 9 This is a microstructure diagram of the precipitation phase morphology of the hub of the GH4151 alloy turbine disk forging blank of Example 1 of the present invention. Fig.10 This is a microstructure diagram of the precipitation phase morphology in the transition zone between the blank and the plate of the GH4151 alloy turbine disk forging according to Example 1 of the present invention. Fig.11 This is a microstructure diagram of the precipitated phase morphology of the GH4151 alloy turbine disk forging blank disk edge of Example 1 of the present invention. Figure 6~Figure 8 It can be seen that the grain size of the turbine disk prepared by the method of the present invention gradually increases from the disk hub to the disk edge area, wherein the grain size of the disk hub area is ASTM 8-10, and the grain size of the disk edge area is ASTM 7-8. Figure 9~Figure 11It can be seen that the size of the secondary γ' strengthening phase precipitated from the turbine disk prepared by the method of the present invention gradually decreases from the disk hub to the disk edge area. The cooling rate in the disk edge area is slow, and the secondary γ' strengthening phase morphology is mainly block-shaped, with an average size of about 240 μm; the cooling rate in the disk hub area is fast, and the secondary γ' strengthening phase morphology is spherical and dispersed, with an average size of about 130 μm; the finer γ' strengthening phase further improves the service strength of the nickel-based alloy disk hub area. After the turbine disk is formed by the method of the present invention, there is no need to perform gradient heat treatment in a special heat treatment tooling, which improves production efficiency, reduces production costs, and has good economic benefits.

[0065] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing a nickel-based alloy dual-performance hollow turbine disk, characterized in that: The following steps are involved: S1) performing large deformation closed final forging in a die on a turbine disk blank whose disk hub thickness is greater than the disk rim thickness to obtain a turbine disk forging blank; the deformation amount of the large deformation closed final forging is the difference between the disk hub thickness and the disk rim thickness of the turbine disk blank; S2) The turbine disk forging blank obtained in step S1) is cooled with a decreasing cooling effect from the disk hub to the disk edge, and then heat treated to obtain a nickel-based alloy dual-performance hollow turbine disk.

2. The preparation method according to claim 1, characterized in that: In step S1), the difference between the hub thickness and the rim thickness of the turbine disk cake blank is 60-80% of the hub thickness of the turbine disk cake blank.

3. The preparation method according to claim 1, characterized in that: In step S1), the hub thickness of the turbine disk cake blank is 140-160 mm, and the disk rim thickness is 30-50 mm.

4. The preparation method according to claim 1, characterized in that: In step S1), the pressing speed of the large deformation closed final forging is 0.01-10 mm / s.

5. The preparation method according to claim 1, characterized in that: In step S1), before the turbine disk blank is subjected to large deformation closed final forging, the step further includes heating the turbine disk blank to 750-850°C for heat preservation, heating the blank to 900-1000°C for heat preservation, and heating the blank to 1100-1150°C for heat preservation; The heating rate is 50-200° C. / h; the insulation time is 1-2 min / mm based on the thickness of the hub of the turbine disk cake.

6. The preparation method according to claim 1, characterized in that: In step S1), after the turbine disk blank is subjected to large deformation closed final forging, the process further includes holding the pressure for 5 to 30 minutes.

7. The preparation method according to claim 1, characterized in that: In step S2), the turbine disk forging blank obtained in step S1) is cooled by using a vortex cooling pipe through a cooling medium to cool the turbine disk forging blank with a decreasing cooling effect from the disk hub to the disk edge; The number of turns of the vortex-shaped cooling pipe is more than 3 turns, and the pipe diameter of the vortex-shaped cooling pipe increases by 5 to 15 mm per turn from the center to the edge.

8. The preparation method according to claim 7, characterized in that: The number of turns of the vortex-shaped cooling pipe is 3 turns, and the pipe diameter of the vortex-shaped cooling pipe is 25-35 mm, 35-45 mm and 45-55 mm from the center to the edge of each turn.

9. A nickel-based alloy dual-performance hollow turbine disk obtained by the preparation method described in any one of claims 1 to 9.

10. A hollow turbine disc forging die, characterized in that: include: An upper die and a lower die; both the upper die and the lower die are provided with a vortex cooling channel vortexing from the core to the edge of the hollow turbine disc forging die; The central portion of the spiral cooling pipeline is provided with a cooling medium inlet, and the edge portion of the pipeline is provided with a cooling medium outlet; The number of turns of the vortex-shaped cooling pipe is more than 3 turns, and the pipe thickness of the vortex-shaped cooling pipe increases by 5 to 15 mm per turn from the center to the edge.

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