Casting process of multi-cascade high-temperature alloy turbine guide vane for aero-engine

Abstract

The application relates to the technical field of precision casting and discloses a casting process for a multiple-assembly high-temperature alloy turbine guide vane for an aero-engine, which comprises the following steps: S1, preparing a vane mold according to the structure of the multiple-assembly high-temperature alloy turbine guide vane; S2, pressing a multiple-assembly high-temperature alloy turbine guide vane wax mold: using the vane mold in step S1 and selecting wax material, a vane wax mold 8 is pressed by adopting an injection molding mode; S3, bonding a mold group: bonding two vane wax molds 8 prepared in step S2 and a pouring system together to form a mold group; S4, preparing an oxide ceramic mold shell, after the mold shell is air-dried, a dewaxing treatment is carried out; S5, pre-burning the oxide ceramic mold shell; and S6, pouring alloy liquid. The multiple-assembly turbine guide vane casting produced through the improvement of the vane wax mold preparation bonding scheme, the oxide ceramic mold preparation process and the pouring process meets the index requirements in terms of grain size, metallurgy and size control, and the production is stable.

Description

Technical Field

[0001] This invention relates to the field of precision casting technology, specifically to the casting process of multi-unit high-temperature alloy turbine guide vanes for aero-engines. Background Technology

[0002] The function of the turbine guide vane of an aero-engine is to convert part of the thermal energy of the airflow into kinetic energy and to flow out in a certain direction to drive the turbine to do work. The working conditions of the guide vane are extremely harsh. In addition to being subjected to large aerodynamic forces and unstable pulsating loads, it is also surrounded by high-temperature combustion gases. The temperature is high, the temperature changes are large, and the internal temperature gradient of the blade is large, which makes it easy for thermal fatigue cracks to occur.

[0003] To improve the heat resistance of power turbine guide vanes and facilitate assembly and replacement, reduce the load on individual vanes, and decrease the risk of cracks caused by vibration, guide vanes are usually designed as complex multi-unit high-temperature alloy vanes with large differences in wall thickness and many hot spots. This leads to turbulent flow of molten metal during casting, difficulty in controlling the cooling sequence, and inconsistent shrinkage of various structures. As a result, the metallurgical quality and dimensions of the castings fail to meet the technical requirements, resulting in a low pass rate.

[0004] In the existing technology, multiple modules set on the base plate and the top cover are spliced ​​together to form the blade wax mold cavity; then, the blade wax mold is bonded to the gating system to form a module; after the oxide ceramic shell is made based on the module, it is air-dried and dewaxed; finally, the triple turbine guide blade casting is obtained by side casting.

[0005] The problems include:

[0006] Low mold alignment accuracy leads to low forming accuracy of blade wax molds, which in turn affects the forming accuracy of oxide ceramic shells and ultimately the forming accuracy of turbine guide blade castings.

[0007] The large micro-deformation caused by the concentration of thermal stress in the mold can also lead to low forming accuracy of the blade wax mold, which affects the forming accuracy of the oxide ceramic shell and ultimately the forming accuracy of the turbine guide blade casting.

[0008] Oxide ceramic shells have poor overall performance, with problems such as poor high-temperature strength and high surface roughness. They are prone to cracking or slag inclusions during casting, which affects the metallurgical quality of the castings.

[0009] Therefore, in order to solve the above problems, a casting process for multi-unit high-temperature alloy turbine guide vanes for aero-engines is proposed. Summary of the Invention

[0010] The purpose of this invention is to provide a casting process for multi-unit high-temperature alloy turbine guide vanes for aero-engines. By improving the process, molds, oxide ceramic shells and other structures, turbine guide vane castings with higher precision can be obtained, thereby solving the above-mentioned problems.

[0011] To achieve the above objectives, the present invention provides the following technical solution:

[0012] The casting process of multi-unit high-temperature alloy turbine guide vanes for aero-engines, including...

[0013] The following steps are required:

[0014] S1: Fabricate blade molds based on the structure of multi-unit high-temperature alloy turbine guide vanes;

[0015] The blade mold includes a base plate and a top cover. An outer arc blade mold block is installed at the front end of the upper side of the base plate via a linear sliding assembly. An inner arc blade mold block is installed at the rear end of the upper side of the base plate via a linear sliding assembly. Side mold sliders are installed at both ends of the upper side of the base plate via arc sliding assemblies. Several adjacent bottom blade mold blocks are fixedly installed at the center of the upper side of the base plate. Several adjacent top blade mold blocks are fixedly installed on the lower side of the top cover. When the base plate and the top cover are fastened together, a blade wax mold cavity is formed between the outer arc blade mold block, the inner arc blade mold block, the bottom blade mold block, and the top blade mold block. A wax injection nozzle is connected to the front side of the blade wax mold cavity.

[0016] S2: Pressing wax mold of multi-unit high temperature alloy turbine guide vane: Using the blade mold in step S1 and selecting wax material, press out the blade wax mold by injection molding.

[0017] S3: Adhesive module: The two blade wax molds prepared in step S2 are bonded together with the gating system to form a module;

[0018] S4: Making oxide ceramic shell: After immersing the module in the slurry, take it out, sprinkle oxide ceramic sand on the surface of the module and dry it to form a layer structure. Repeat this operation until an oxide ceramic shell with a seven-layer structure is formed on the surface of the module. After the shell is air-dried, dewaxing is performed.

[0019] In the seven-layer oxide ceramic shell, the slurry used for the first layer is a mixture of cobalt aluminate powder, zirconium oxide powder, and silica molten metal in a weight ratio of ::1; the slurry used for the second layer is a mixture of corundum powder and silica molten metal in a weight ratio of ::1, and the sand used is corundum sand #60; the slurry used for the third to seventh layers is a mixture of bauxite powder and silica molten metal in a weight ratio of ::1, the sand used for the third layer is coal gangue sand #36, the sand used for the fourth to sixth layers is coal gangue sand #24, and the seventh layer is not coated with sand;

[0020] S5: Pre-firing of oxide ceramic shell: After wrapping the oxide ceramic shell with insulation cotton, place it in a sand box and then fire it. The firing temperature is 1010℃~1030℃. After the oxide ceramic shell enters the furnace and reaches the firing temperature, the holding time shall not be less than 6 hours.

[0021] S6: Alloy liquid casting: Select nickel-based high-temperature alloy liquid for casting. Pour the alloy liquid into the pre-fired oxide ceramic mold shell. The casting temperature is 1520℃~1530℃ and the casting time is 2 seconds~3 seconds. After casting, the multi-unit high-temperature alloy turbine guide vane casting for aero-engine is obtained.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] Significantly improved molding precision: The mold is precisely positioned through straight / arc sliding components, and the interlocking design of multi-directional docking blocks and docking grooves can reduce splicing errors and ensure the casting requirements of complex curved surfaces; the split top blade shape block design has advantages such as thermal expansion compensation capability, reduced deformation caused by thermal stress, smaller deformation of blade wax mold, higher production efficiency, and lower cost.

[0024] Oxide ceramic shell performance optimization: The structure of seven layers of different materials gives the oxide better high-temperature strength, high-temperature oxidation resistance, and excellent chemical stability.

[0025] This invention improves the blade wax mold preparation and bonding scheme, oxide ceramic mold preparation process, and casting process, enabling the produced multi-unit turbine guide vane castings to meet the requirements in terms of grain size, metallurgy, and dimensional control, and ensuring stable production. Attached Figure Description

[0026] Figure 1 This is a perspective view of the blade wax model in this invention;

[0027] Figure 2 This is a perspective view of the blade mold being engaged in this invention.

[0028] Figure 3 This is a perspective view of the upper side structure of the base plate in this invention;

[0029] Figure 4 This is a perspective view of the lower side structure of the upper cover in this invention;

[0030] Figure 5 This is a perspective view of the top blade symbol block and the bottom blade symbol block in contact in this invention;

[0031] Figure 6 This is a perspective view of the bottom docking block and the bottom docking groove when they are separated in this invention;

[0032] Figure 7 This is a front view of the module in this invention.

[0033] In the diagram: 1. Base plate, 2. Locking ring, 3. Wax injection nozzle, 4. Linear sliding assembly, 5. Top cover, 6. Arc sliding assembly, 7. Side mold slider, 8. Blade wax mold, 81. Outer arc slab mold, 82. Blade mold, 83. Inner arc slab mold, 9. Inner arc slab mold symbol block, 10. Bottom blade symbol block, 11. End joint groove, 12. End joint block, 13. Top blade symbol block, 14. Bottom joint block, 15. Bottom joint groove, 16. Sprue cup, 17. Angled sprue, 18. Horizontal sprue, 19. Vertical sprue, 20. Outer arc slab mold symbol block, 21. Side joint groove, 22. Side joint block. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Please see Figure 1 , Figure 2 and Figure 7 This invention provides a casting process for multi-unit high-temperature alloy turbine guide vanes for aero-engines, comprising the following steps:

[0036] S1: Fabricate blade molds based on the structure of multi-unit high-temperature alloy turbine guide vanes;

[0037] S2: Pressing multi-unit high-temperature alloy turbine guide vane wax mold: Using the blade mold in step S1 and selecting wax material, press the blade wax mold 8 by injection molding.

[0038] S3: Adhesive module: The two blade wax molds 8 prepared in step S2 are bonded together with the gating system to form a module;

[0039] S4: Making oxide ceramic shell: After immersing the module in the slurry, take it out, sprinkle oxide ceramic sand on the surface of the module and dry it to form a layer structure. Repeat this operation until an oxide ceramic shell with a seven-layer structure is formed on the surface of the module. After the shell is air-dried, dewaxing is performed.

[0040] S5: Pre-firing of oxide ceramic shell: After wrapping the oxide ceramic shell with insulation cotton, place it in a sand box and then fire it. The firing temperature is 1010℃~1030℃. After the oxide ceramic shell enters the furnace and reaches the firing temperature, the holding time shall not be less than 6 hours.

[0041] S6: Alloy liquid casting: Select nickel-based high-temperature alloy liquid for casting. Pour the alloy liquid into the pre-fired oxide ceramic mold shell. The casting temperature is 1520℃~1530℃ and the casting time is 2 seconds~3 seconds. After casting, the multi-unit high-temperature alloy turbine guide vane casting for aero-engine is obtained.

[0042] Please see Figure 1 In S2, the form of the blade wax model 8 is as follows:

[0043] The blade wax mold 8 includes an outer arc sill mold 81, a blade mold 82, and an inner arc sill mold 83. The outer arc sill mold 81 and the inner arc sill mold 83 are arranged concentrically. The blade mold 82 is integrally formed between the outer arc sill mold 81 and the inner arc sill mold 83. There are 3 to 7 blade molds evenly distributed along the outer arc sill mold 81.

[0044] Depending on the type of multi-unit high-temperature alloy turbine guide vane casting, the corresponding blade mold can be selected to produce multi-unit high-temperature alloy turbine guide vane castings with the corresponding number of blades. The shape of blade wax mold 8 is the shape of the multi-unit high-temperature alloy turbine guide vane casting.

[0045] Please see Figure 3 and Figure 4 In S1, the specific structure of the blade mold is as follows:

[0046] The blade mold includes a base plate 1 and a top cover 5. An outer arc rafter mold block 20 is installed on the front end of the upper side of the base plate 1 via a linear sliding component 4. The linear sliding component 4 at the front end allows the outer arc rafter mold block 20 to move in the front-back direction.

[0047] An inner arc rafter template block 9 is installed at the rear end of the upper side of the base plate 1 via a linear sliding component 4; the setting of the rear linear sliding component 4 allows the inner arc rafter template block 9 to also move in the front-back direction.

[0048] The left and right ends of the upper side of the base plate 1 are equipped with side mold sliders 7 via arc sliding components 6; the setting of the arc sliding components 6 at both ends allows the left and right side mold sliders 7 to swing closer to each other or further away from each other along the arc.

[0049] Several adjacent bottom blade-shaped blocks 10 are fixedly installed at the center of the upper side of the base plate 1, and several adjacent top blade-shaped blocks 13 are fixedly installed on the lower side of the upper cover 5. When the base plate 1 and the upper cover 5 are fastened together by bolts, a blade wax mold cavity is formed between the outer arc rafter mold block 20, the inner arc rafter mold block 9, the bottom blade-shaped blocks 10, and the top blade-shaped blocks 13. A wax injection nozzle 3 is installed on the front side of the blade wax mold cavity; specifically, the side mold slider 7 A cavity conforming to the shape of the blade mold 82 is formed between the top blade symbol block 13 and the bottom blade symbol block 10. A cavity conforming to the shape of the outer arc rafter mold 81 is formed between the front ends of the top blade symbol block 13 and the bottom blade symbol block 10 and the outer arc rafter mold symbol block 20. A cavity conforming to the shape of the inner arc rafter mold 83 is formed between the rear ends of the top blade symbol block 13 and the bottom blade symbol block 10 and the inner arc rafter mold symbol block 9. The three cavities are interconnected to form a complete blade wax mold cavity.

[0050] The linear sliding assembly 4 includes a linear slide groove 41 and a linear slide rail 42. Linear slide grooves 41 are provided on both the front and rear sides of the upper side of the base plate 1. The linear slide grooves 41 are all arranged along the front-rear direction, and their cross-sections are cross-shaped. The cross-sections of the linear slide rails 42 are inverted T-shaped. Linear slide rails 42 are slidably installed within each linear slide groove 41. The upper side of the front linear slide rail 42 is fixedly assembled with the outer arc rafter mold block 20, and the upper side of the rear linear slide rail 42 is fixedly assembled with the inner arc rafter mold block. 9. Fixed assembly; Further, a first handle can also be fixedly installed on the upper side of the linear slide rail 42. Holding the first handle, the linear slide rail 42 is driven to move along the linear slide groove 41 to adjust the position of the outer arc slab mold block 20 and the inner arc slab mold block 9. When the outer arc slab mold block 20 and the inner arc slab mold block 9 are close to each other and abut against the side mold slider 7, they are in the working position. When the outer arc slab mold block 20 and the inner arc slab mold block 9 are far apart from each other, they are in the demolding position.

[0051] The arc sliding assembly 6 includes an arc-shaped slide rail 61 and an arc-shaped slide groove 62. Arc-shaped slide grooves 62 are provided on the left and right sides of the upper side of the base plate 1. The two arc-shaped slide rails 61 are symmetrically arranged, and the cross-section of the arc-shaped slide groove 62 is cross-shaped, while the cross-section of the arc-shaped slide rail 61 is inverted T-shaped. Arc-shaped slide rails 61 are slidably installed in the arc-shaped slide grooves 62. Side mold sliders 7 are fixedly installed on the upper side of the arc-shaped slide rails 61. Furthermore, a second handle can also be fixedly installed on the upper side of the arc-shaped slide rail 61. Holding the second handle drives the arc-shaped slide rail 61 to swing along the arc-shaped slide groove 62 along the arc. When the two side mold sliders 7 are close to each other and abut against the bottom blade-shaped block 10, they are in the working position. When the two side mold sliders 7 are far apart, they are in the demolding position.

[0052] Please see Figure 3 , Figure 4 , Figure 5 and Figure 6To improve the molding quality of the blade wax mold 8:

[0053] The bottom of the top blade symbol block 13 is provided with a bottom docking block 14, and the bottom blade symbol block 10 is provided with a bottom docking groove 15 for inserting the bottom docking block 14; the front and rear ends of the top blade symbol block 13 are both fixedly installed with end docking blocks 12, and the top of the outer arc rafter mold symbol block 20 and the inner arc rafter mold symbol block 9 are both provided with end docking grooves 11 for inserting the end docking blocks 12; the left side of the leftmost top blade symbol block 13 and the left side of the bottom blade symbol block 10, and the right side of the rightmost top blade symbol block 13 and the bottom blade symbol block 10 are both fixedly installed with side docking blocks 22, and the side mold slider 7 is provided with a side docking groove 21 for inserting the side docking blocks 22.

[0054] By inserting the side docking block 22 into the side docking groove 21, the side mold slider 7 and the blade shape block can be accurately positioned laterally, preventing wax pattern displacement during casting. The cooperation between the bottom docking block 14 and the bottom docking groove 15 ensures seamless vertical fitting between the top blade shape block 13 and the bottom blade shape block 10, avoiding layering misalignment. The insertion of the end docking block 12 into the end docking groove 11 ensures the positional accuracy of the outer arc rafter mold shape block 20 and the inner arc rafter mold shape block 9. The coordinated positioning effect in multiple locations and directions can control the module splicing error within 0.02mm, ultimately ensuring that the accuracy of the blade wax pattern cavity can meet the casting requirements of the complex curved surface of the high-temperature alloy turbine guide blade.

[0055] Please see Figure 6 The specific structure of the top leaf-shaped block 13:

[0056] Each top leaf symbol block 13 is composed of four symbol pieces, with the mating surfaces of the two front symbol pieces and the two rear symbol pieces being staggered.

[0057] Compared to the traditional integral top blade shape block, the split top blade shape block 13 can decompose thermal stress in multiple dimensions during wax injection, avoiding stress concentration. The overall surface deformation is minimal, thus ensuring the shape accuracy and surface quality of the blade mold 82.

[0058] In addition, the shaped pieces can be easily processed and disassembled for replacement, which improves production efficiency and reduces maintenance costs.

[0059] Please see Figure 4 Setting of locking ring 2:

[0060] A locking ring 2 is fixedly installed on the lower side of the upper cover 5, and the top blade symbol block 13 is located inside the locking ring 2. When the bottom plate 1 and the upper cover 5 are fastened together, the locking ring 2 abuts against the outer arc rafter mold symbol block 20, the side mold slider 7, and the inner arc rafter mold symbol block 9. Furthermore, the outer arc rafter mold symbol block 20, the side mold slider 7, and the inner arc rafter mold symbol block 9 all have a downward slope (inclined from bottom to top and inward) on their sidewalls away from the bottom blade symbol block 10, and the inner side of the locking ring 2 has an upward slope that matches the downward slope.

[0061] As the base plate 1 and the top cover 5 are gradually fastened together, the upper and lower slopes are gradually pressed together. The outer arc slab mold block 20, the side mold slider 7, and the inner arc slab mold block 9 are locked in place by the surrounding enclosure and tightness of the locking ring 2. This can withstand the injection pressure during wax injection and prevent gaps from forming between the outer arc slab mold block 20, the side mold slider 7, and the inner arc slab mold block 9.

[0062] The outer arc slab mold block 20 has a countersunk hole on the side away from the inner arc slab mold block 9, and the locking ring 2 has a through hole on the side away from the inner arc slab mold block 9. The same wax injection nozzle 3 is inserted into the countersunk hole and the through hole. After the bottom plate 1 and the top cover 5 are fastened together, the through hole and the countersunk hole are aligned coaxially, which facilitates the installation of the wax injection nozzle 3 and allows the wax injection nozzle 3 to be connected to the blade wax mold cavity.

[0063] The specific form of the seven-layer oxide ceramic shell:

[0064] In the seven-layer oxide ceramic shell, the slurry used for the first layer is a mixture of cobalt aluminate powder, zirconium oxide powder and silicon molten adhesive in a weight ratio of (0.8~1.0):(3.0~3.5):1; it is used to form a dense microcrystalline structure and improve the surface finish.

[0065] The slurry used in the second layer structure is a mixture of corundum powder and silica molten material in a weight ratio of (1.0~2.5):1, and the sand used is corundum sand #60; it is used to enhance the erosion resistance.

[0066] The slurry used for the third to seventh layers is a mixture of bauxite powder and silica molten adhesive in a weight ratio of (1.0 to 3.0): 1. The third layer is sprinkled with coal gangue sand #36, the fourth to sixth layers are sprinkled with coal gangue sand #24, and the seventh layer is not sprinkled with sand. The decreasing sand particle size can achieve a gradient transition in strength, and the absence of sand in the seventh layer can form a smooth casting surface.

[0067] This gives the oxide ceramic shell better high-temperature strength, high-temperature oxidation resistance and excellent chemical stability, ensuring the precision of the complex curved surface forming of turbine blades.

[0068] Please see Figure 7 The specific structure of the gating system:

[0069] The gating system includes a gating cup 16, a horizontal runner 18, a vertical runner 19, a sprue 17, and several feeding risers. The horizontal runner 18 is bonded to the lower side of the gating cup 16 through the vertical runner 19. Sprue 17s are bonded to both sides of the gating cup 16. An oxide ceramic shell is bonded between the sprue 17 and the horizontal runner 18 on the same side. An inner gate is provided at the bonding point between the oxide ceramic shell and the sprue 17 and the horizontal runner 18. The oxide ceramic shell is also provided with feeding risers and vents.

[0070] Feeding risers are placed in the thick-walled or hot-spot areas of castings according to casting requirements. They utilize the final solidification characteristics of the molten metal in the feeding riser to compensate for shrinkage and prevent shrinkage defects.

[0071] In addition, the gating system adopts a bottom-pouring method; the alloy liquid rises from the bottom of the oxide ceramic shell to fill it, which can reduce the direct impact of the liquid flow on the oxide ceramic shell and reduce the risk of oxide inclusions and porosity defects.

[0072] The risers and ingates of the oxide ceramic mold are wrapped with a layer of insulation cotton, and then the oxide ceramic mold is wrapped with insulation cotton as a whole.

[0073] Insulating cotton at the feeding riser can delay local cooling, extend the feeding time of the molten metal at the feeding riser, and reduce shrinkage defects; wrapping at the ingate can reduce heat loss of the alloy liquid, maintain the flow filling capacity, and avoid incomplete filling problems; wrapping the entire mold with insulating cotton can evenly dissipate heat from the mold shell, reduce temperature gradient, and reduce the risk of thermal stress cracking.

[0074] In step S6, the nickel-based superalloy liquid is obtained by heating and melting K477 nickel-based superalloy and refining it. The refining temperature is 1550℃~1580℃ and the refining time is not less than 10 minutes.

[0075] The chemical composition of K477 nickel-based superalloy is (wt.%):

[0076] C: 0.05~0.09%; Cr: 14.00~15.25%; Mo: 3.90~4.50%; Co: 14.0~16.0%; Al: 4.0~4.6%; Ti: 3.0~3.7%; Fe: ≤1.00%; Si: ≤0.015%; S≤0.010%; B: 0.012~0.020%; Zr: ≤0.040%; Ce: ≤0.100%; balance Ni.

[0077] In step S6, the interval between the end of pouring and the time when the casting is removed from the furnace shall not exceed 5 minutes, and the time for the casting to be left to stand after pouring shall not be less than 4 hours.

[0078] The following is an example:

[0079]

[0080] The multi-unit power turbine guide vane castings for aero-engines prepared through the above embodiments produce blades with excellent performance in terms of grain size, metallurgy, and dimensional control; the blade surface has fine and uniform grain size, with an average grain size ≤1.41mm, and no columnar crystals perpendicular to the intake and exhaust edges; X-ray and fluorescence penetrant testing shows that the blade body area is free of porosity, and the blade body has point defects ≤1.0mm; the blade profile dimensions measured by coordinate measuring machine (CMM) deviate from the theoretical value by ≤0.1mm.

[0081] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0082] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A casting process for multi-unit high-temperature alloy turbine guide vanes for aero-engines, characterized by: Includes the following steps: S1: Fabricate blade molds based on the structure of multi-unit high-temperature alloy turbine guide vanes; The blade mold includes a base plate (1) and a top cover (5). An outer arc slab mold block (20) is installed on the front end of the upper side of the base plate (1) through a linear sliding component (4). An inner arc slab mold block (9) is installed on the rear end of the upper side of the base plate (1) through a linear sliding component (4). Side mold sliders (7) are installed on both the left and right ends of the upper side of the base plate (1) through an arc sliding component (6). Several adjacent bottom blade mold blocks (10) are fixedly installed at the center of the upper side of the base plate (1). Several adjacent top blade mold blocks (13) are fixedly installed on the lower side of the top cover (5). When the base plate (1) and the top cover (5) are fastened together, a blade wax mold cavity is formed between the outer arc slab mold block (20), the inner arc slab mold block (9), the bottom blade mold block (10), and the top blade mold block (13). A wax injection nozzle (3) is connected to the front side of the blade wax mold cavity. The bottom of the top blade symbol block (13) is provided with a bottom docking block (14), and the bottom blade symbol block (10) is provided with a bottom docking groove (15) for inserting the bottom docking block (14). Both ends of the top blade shaped block (13) are fixedly installed with end docking blocks (12), and the top of the outer arc rafter mold shaped block (20) and the inner arc rafter mold shaped block (9) are provided with end docking grooves (11) for inserting the end docking blocks (12). Side mating blocks (22) are fixedly installed on the left side of the top blade symbol block (13) and the bottom blade symbol block (10) at the far left end, and on the right side of the top blade symbol block (13) and the bottom blade symbol block (10) at the far right end. The side mold slider (7) has a side mating groove (21) for inserting the side mating block (22). Each of the top blade symbol blocks (13) is composed of four symbol pieces, with the mating surfaces of the two front symbol pieces and the mating surfaces of the two rear symbol pieces being staggered. S2: Pressing multi-unit high-temperature alloy turbine guide vane wax mold: Using the blade mold in step S1 and selecting wax material, the blade wax mold is pressed out by injection molding (8). S3: Adhesive module: Two blade wax molds (8) prepared in step S2 are bonded together with the gating system to form a module; S4: Making oxide ceramic shell: After immersing the module in the slurry, take it out, sprinkle oxide ceramic sand on the surface of the module and dry it to form a layer structure. Repeat this operation until an oxide ceramic shell with a seven-layer structure is formed on the surface of the module. After the shell is air-dried, dewaxing is performed. In the seven-layer oxide ceramic shell, the slurry used for the first layer is a mixture of cobalt aluminate powder, zirconium oxide powder, and silica molten metal in a weight ratio of (0.8-1.0):(3.0-3.5):1; the slurry used for the second layer is a mixture of corundum powder and silica molten metal in a weight ratio of (1.0-2.5):1, and the sand used is corundum sand #60; the slurry used for the third to seventh layers is a mixture of bauxite powder and silica molten metal in a weight ratio of (1.0-3.0):1, the sand used for the third layer is coal gangue sand #36, the sand used for the fourth to sixth layers is coal gangue sand #24, and the seventh layer is not coated with sand; S5: Pre-firing of oxide ceramic shell: After wrapping the oxide ceramic shell with insulation cotton, place it in a sand box and then fire it. The firing temperature is 1010℃~1030℃. After the oxide ceramic shell enters the furnace and reaches the firing temperature, the holding time shall not be less than 6 hours. S6: Alloy liquid casting: Select nickel-based high-temperature alloy liquid for casting. Pour the alloy liquid into the pre-fired oxide ceramic mold shell. The casting temperature is 1520℃~1530℃ and the casting time is 2 seconds~3 seconds. After casting, the multi-unit high-temperature alloy turbine guide vane casting for aero-engine is obtained.

2. The casting process for multi-unit high-temperature alloy turbine guide vanes for aero-engines according to claim 1, characterized in that: The blade wax mold (8) includes an outer arc slab mold (81), a blade mold (82), and an inner arc slab mold (83). The outer arc slab mold (81) and the inner arc slab mold (83) are arranged concentrically. The blade mold (82) is integrally formed between the outer arc slab mold (81) and the inner arc slab mold (83). The blade mold (82) consists of 3 to 7 blades evenly distributed along the outer arc slab mold (81).

3. The casting process for multi-unit high-temperature alloy turbine guide vanes for aero-engines according to claim 1, characterized in that: A locking ring (2) is fixedly installed on the lower side of the upper cover (5), and the top blade shaped block (13) is located inside the locking ring (2). When the bottom plate (1) and the upper cover (5) are fastened together, the locking ring (2) abuts against the outer arc rafter mold shaped block (20), the side mold slider (7), and the inner arc rafter mold shaped block (9). The outer arc slab mold block (20) has a countersunk hole on the side away from the inner arc slab mold block (9), and the locking ring (2) has a through hole on the side away from the inner arc slab mold block (9). The same wax injection nozzle (3) is inserted into the countersunk hole and the through hole, so that the wax injection nozzle (3) can communicate with the blade wax mold cavity.

4. The casting process for multi-unit high-temperature alloy turbine guide vanes for aero-engines according to claim 1, characterized in that: The gating system includes a gating cup (16), a horizontal gating (18), a vertical gating (19), a sloping gating (17), and several feeding risers. The lower side of the gating cup (16) is connected to the horizontal gating (18) through the vertical gating (19). Both sides of the gating cup (16) are connected to the sloping gating (17). An oxide ceramic shell is connected between the sloping gating (17) and the horizontal gating (18) on the same side. An inner gate is provided at the bonding point between the oxide ceramic shell and the sloping gating (17) and the horizontal gating (18). The oxide ceramic shell is also provided with feeding risers and vents. The gating system adopts a bottom-pouring method.

5. The casting process for multi-unit high-temperature alloy turbine guide vanes for aero-engines according to claim 4, characterized in that: The feeding riser and ingate of the oxide ceramic shell are wrapped with a layer of insulation cotton, and then the oxide ceramic shell is completely wrapped with insulation cotton.

6. The casting process for multi-unit high-temperature alloy turbine guide vanes for aero-engines according to claim 1, characterized in that: In step S6, the nickel-based superalloy liquid is obtained by heating and melting K477 nickel-based superalloy and refining it. The refining temperature is 1550℃~1580℃ and the refining time is not less than 10 minutes.

7. The casting process for multi-unit high-temperature alloy turbine guide vanes for aero-engines according to claim 1, characterized in that: In step S6, the interval between the end of pouring and the time when the casting is removed from the furnace shall not exceed 5 minutes, and the time for the casting to be left to stand after pouring shall not be less than 4 hours.

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