Manufacturing method of controllable heterogeneous and reverse deformation hollow turbine blade

Abstract

The application belongs to the technical field of additive manufacturing, and discloses a manufacturing method of a controllable heterogeneous crystal and reverse deformation hollow turbine blade, which comprises the following steps: obtaining a three-dimensional model of a blade after reverse deformation based on an original design model of a hollow turbine blade and deformation rules thereof; obtaining a three-dimensional model of a core-shell integrated casting mold based on the three-dimensional model of the blade after reverse deformation; obtaining a core-shell integrated casting mold master mold by means of a light-curing laser forming technology based on the three-dimensional model of the core-shell integrated casting mold; obtaining a core-shell integrated casting mold based on the core-shell integrated casting mold master mold; and obtaining a hollow turbine blade by means of a directional solidification technology based on the core-shell integrated casting mold. The manufacturing method can be used to prepare a single-crystal hollow turbine blade with high profile precision, and can solve technical problems such as eccentric core perforation and rim plate heterogeneous crystal.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing technology, and specifically relates to a method for manufacturing hollow turbine blades with controllable heterogeneous crystals and reverse deformation. Background Technology

[0002] Turbine blades are one of the key components of aero engines and gas turbines. They generally operate in harsh environments such as high-temperature and hot-corrosion environments or complex stress environments. Explanation: The aforementioned harsh operating environments place high demands on the performance level of turbine blades.

[0003] Currently, single-crystal hollow turbine blades are typically formed using investment casting. However, in actual production, investment-cast blades suffer from low profile accuracy, large wall thickness deviations, and a tendency to generate impurities at the rim, resulting in a high scrap rate. Therefore, controlling the profile accuracy and impurity control of single-crystal hollow turbine blades has become one of the major technical challenges in the development of new aero-engines. Summary of the Invention

[0004] The purpose of this invention is to provide a method for manufacturing hollow turbine blades with controllable heterogeneous grains and reverse deformation, thereby solving one or more of the aforementioned technical problems. The hollow turbine blade manufacturing method provided by this invention produces single-crystal hollow turbine blades with high profile accuracy and can solve technical problems such as eccentric perforation and heterogeneous grains in the rim plate.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention provides a method for manufacturing hollow turbine blades with controllable heterogeneous crystals and reverse deformation, comprising the following steps:

[0007] Step 1: Based on the original design model of the hollow turbine blade and its deformation law, obtain the three-dimensional model of the blade after inverse deformation;

[0008] Step 2: Based on the three-dimensional model of the blade after the reverse deformation, obtain a three-dimensional model of the integrated core and shell casting mold; wherein, the integrated core and shell casting mold three-dimensional model includes a core and a shell; the core and the shell are connected by a film gas column, and a part of the shell is a variable porosity shell;

[0009] Step 3: Based on the integrated core and shell casting three-dimensional model, the integrated core and shell casting master mold is prepared by photopolymerization laser forming technology;

[0010] Step 4: Inject ceramic slurry into the cavity of the integrated core and shell casting master mold to form an integrated core and shell casting green blank; after the ceramic slurry crosslinks and solidifies, freeze-dry, degrease, and sinter the integrated core and shell casting green blank to obtain an integrated core and shell casting mold.

[0011] Step 5: Based on the integrated core and shell mold, hollow turbine blades are prepared by directional solidification technology.

[0012] A further improvement of the present invention is that, in step 1, the step of obtaining the deformation law includes:

[0013] Based on the original design model of the hollow turbine blade, turbine blade samples were prepared using a directional solidification process.

[0014] The turbine blade sample was scanned using a 3D scanning device to obtain sample blade data;

[0015] The deformation pattern was obtained by comparing the sample blade data with the original design model data of the hollow turbine blade.

[0016] A further improvement of the present invention is that, in step 1, the step of obtaining the three-dimensional model of the blade after inverse deformation specifically includes:

[0017] Based on the deformation law, the displacement field deviation is obtained;

[0018] The blade's three-dimensional model after inverse deformation is obtained by inverse solution based on displacement field deviation.

[0019] A further improvement of the present invention is that, in step 2, the step of obtaining the three-dimensional model of the integrated core and shell casting mold based on the three-dimensional model of the blade after the reverse deformation specifically includes:

[0020] Based on the three-dimensional model of the blade after reverse deformation, a resin master mold and a gating system are obtained. The resin master mold includes a blade resin model and a resin shell. The blade resin model is obtained based on the three-dimensional model of the blade after reverse deformation. The resin shell is a conformal structure to the three-dimensional model of the blade after reverse deformation. The blade resin model is disposed within the resin shell, and the blade resin model and the resin shell form a shell cavity. The interior of the blade resin model forms a core cavity. The inner wall of the resin shell is provided with multiple honeycomb structural units of different diameters and thicknesses for burn-off to form a variable porosity shell. Air film pores are formed on the blade resin model.

[0021] Based on the resin master mold and gating system, a three-dimensional model of the integrated core and shell mold is obtained.

[0022] A further improvement of the present invention is that,

[0023] The diameter of the air film pore is greater than or equal to 0.4 mm.

[0024] A further improvement of the present invention is that,

[0025] The diameter of a single honeycomb structural unit varies from 0.1 mm to 0.5 mm.

[0026] A further improvement of the present invention is that,

[0027] The thickness of the honeycomb structure unit varies from 0 mm to 3 mm.

[0028] A further improvement of the present invention is that,

[0029] The shell thickness of the integrated core and shell mold is 2mm to 8mm.

[0030] A further improvement of the present invention is that,

[0031] The ceramic slurry contains a sintering expansion agent.

[0032] A further improvement of the present invention is that,

[0033] The matrix material of the ceramic slurry is alumina, silicon oxide, or silicon carbide;

[0034] The sintering expansion agent is aluminum silicon, aluminum powder, yttrium oxide, or silicon powder.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The hollow turbine blade manufacturing method provided by this invention utilizes the speed of photopolymerization laser forming, enabling multiple reverse deformation iterations in a short time to achieve the optimal surface accuracy requirements for hollow turbine blade casting. By designing the honeycomb structure of the master mold resin shell and the cavity gap, the shell wall thickness can be precisely controlled and the preparation of a shell with variable porosity can be achieved. This allows for accurate control of the temperature field during turbine blade casting, eliminating the generation of impurities. Through photopolymerization laser rapid forming, film pores can be directly formed on the blade. With debinding and sintering, the core and shell will be connected by film pore columns, allowing film pores to be directly formed during metal casting. This also prevents the core from creeping in the molten metal, which could lead to turbine blade decentering, thus achieving precise manufacturing of hollow turbine blades. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art are briefly introduced below; obviously, the drawings described below are some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram comparing the cross-sections of the hollow turbine blade prototype, after deformation, and after reverse deformation according to the deformation in this embodiment of the invention.

[0039] Figure 2 This is a schematic diagram of the structure of the resin master mold in an embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram of the honeycomb structure on the resin master mold in an embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram of the structure of the core, shell, and air film perforation column in an embodiment of the present invention;

[0042] Explanation of the reference numerals in the diagram:

[0043] 1. Blade resin model; 2. Resin shell; 3. Shell cavity; 4. Core cavity; 5. Film cooling pores; 6. Core; 7. Shell; 8. Film cooling pore column; 9. Variable porosity shell. Detailed Implementation

[0044] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. 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 should fall within the scope of protection of the present invention.

[0045] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0046] The present invention will now be described in further detail with reference to the accompanying drawings:

[0047] Please see Figure 1 and Figure 4 The present invention provides a method for the precise manufacturing of hollow turbine blades with controllable heterogeneous crystals and reverse deformation, comprising the following steps:

[0048] Step 1: Based on the original design model and deformation law of the hollow turbine blade, obtain the three-dimensional model of the blade after inverse deformation. Explainingly, the steps for obtaining the deformation law include: preparing turbine blade samples using a directional solidification process based on the original design model of the hollow turbine blade; scanning the turbine blade samples using a three-dimensional scanning device to obtain sample blade data; comparing the sample blade data with the data from the original design model of the turbine blade to derive the deformation law. Further explaining, the steps for obtaining the three-dimensional model of the blade after inverse deformation include: obtaining the displacement field deviation based on the deformation law; performing inverse solving based on the displacement field deviation to obtain the three-dimensional model of the blade after inverse deformation. An example is... Figure 1 As shown; specifically, the above-mentioned three-dimensional model of the blade after reverse deformation can be designed using three-dimensional modeling software such as UG, ProE or SolidWorks;

[0049] Step 2: Based on the three-dimensional model of the blade after reverse deformation, obtain a three-dimensional model of the integrated core and shell casting mold; wherein, the integrated core and shell casting mold three-dimensional model includes: core 6 and shell 7; core 6 and shell 7 are connected by air film pore columns 8, and a predetermined area of ​​shell 7 is a variable porosity shell 9, for example as follows: Figure 4 As shown; for illustrative purposes, the aforementioned pre-defined regions are determined based on temperature field simulations during the directional solidification process of hollow turbine blades;

[0050] Step 3: Based on the three-dimensional model of the integrated core and shell casting mold, the integrated core and shell casting master mold is prepared by photopolymerization laser forming technology;

[0051] Step 4: The prepared ceramic slurry is injected into the cavity of the integrated core and shell casting mold to form an integrated core and shell casting green body; after the ceramic slurry crosslinks and solidifies, the integrated core and shell casting green body is freeze-dried, degreased, and sintered to obtain an integrated core and shell casting mold; specifically, the shell thickness of the integrated core and shell casting mold is 2mm to 8mm; more preferably, a sintering expansion agent is added to the ceramic slurry; the matrix material of the ceramic slurry is alumina, silicon oxide, silicon carbide, etc., and the sintering expansion agent is aluminum silicon, aluminum powder, yttrium oxide, or silicon powder;

[0052] Step 5: Based on the integrated core and shell mold, hollow turbine blades are prepared by directional solidification technology. Specifically, the manufactured integrated core and shell mold is placed in a directional solidification furnace, and a high-temperature alloy is poured into the integrated core and shell mold by directional solidification technology. After drawing, single crystal or directional crystal blades are obtained. Finally, the desired hollow turbine blades are obtained by post-processing methods such as machining, grinding, and polishing.

[0053] In step 2 of a further preferred embodiment of the present invention, the step of obtaining a three-dimensional model of the integrated core and shell mold based on the three-dimensional model of the blade after reverse deformation specifically includes:

[0054] Based on the three-dimensional model of the blade after inverse deformation, the resin master mold and its gating system are obtained; for example, such as Figure 2 As shown, the resin master mold includes a blade resin model 1 and a resin shell 2; the blade resin model 1 is obtained based on the three-dimensional model of the blade after reverse deformation and can be obtained using photopolymerization laser molding technology; the blade resin model 1 is set inside the resin shell 2, and the blade resin model 1 and the resin shell 2 form a shell cavity 3, and the interior of the blade resin model 1 forms a core cavity 4; as a further example, such as Figure 3 As shown, the inner wall of the resin shell 2 is provided with multiple honeycomb structural units of different diameters and thicknesses, occupying a part of the shell cavity 3; illustratively, the multiple honeycomb structural units are used to burn off and form a variable porosity shell 9; more preferably, the blade resin model 1 can be formed with air film holes 5 for improving cooling efficiency; specifically exemplarily, the diameter of the air film holes 5 is in the range of 0.4 mm or more.

[0055] In this embodiment of the invention, the resin shell 2 is a conformal structure to the three-dimensional model of the blade after reverse deformation; wherein, the inner wall of the resin shell 2 contains a special honeycomb structural unit. Specifically, the diameter of a single honeycomb structural unit varies from 0.1 mm to 0.5 mm, and the thickness varies from 0 mm to 3 mm. This design can form honeycomb structures with different gradients, enabling subsequent shell porosity gradient changes. Further, the honeycomb structure can be burned off during the debinding and sintering process, leaving a ceramic shell with variable porosity.

[0056] The technical solution described above in this invention discloses a precise manufacturing method for hollow turbine blades with controllable impurities and anti-deformation. It involves anti-deformation modeling of the hollow turbine blade to be manufactured, achieving optimal surface accuracy requirements for casting. By designing a honeycomb structure for the resin shell of the master mold, the shell wall thickness can be precisely controlled, and the preparation of a shell with variable porosity can be achieved. This allows for accurate control of the temperature field during turbine blade casting, eliminating the generation of impurities. Rapid laser prototyping via photopolymerization allows for the direct formation of film pores on the blade. With debinding and sintering, the core and shell are connected by film pore columns, allowing for direct formation of film pores during metal casting. Simultaneously, it prevents creep of the core in the molten metal, which could lead to turbine blade eccentricity, thus achieving precise manufacturing of hollow turbine blades.

[0057] In a further preferred embodiment of the present invention, in the step of obtaining the three-dimensional model of the blade after inverse deformation by performing inverse solution based on displacement field deviation, the three-dimensional model of the blade after inverse deformation is obtained by performing multiple iterative calculations; wherein, the accuracy deviation between the hollow turbine blade and the original design model of the hollow turbine blade is less than a preset threshold.

[0058] The method for precisely manufacturing hollow turbine blades with controllable heteromorphic crystals and reverse deformation provided in this invention can be used to prepare hollow turbine blades suitable for aero engines or gas turbines.

[0059] Explanation of the innovative principles of this invention:

[0060] 1) In the existing technology, the current process flow of investment casting mainly includes: design and manufacturing of core mold, pressing core, design and manufacturing of wax mold, assembly and wax injection, slurry coating and shell making, drying shell, dewaxing, sintering, pouring metal, core removal, laser drilling and other steps; the above process has the following problems: the core and shell are assembled separately, which can easily lead to positioning errors and core deviation and perforation; the thickness of the slurry coating and shell making is difficult to control, which can easily lead to uneven temperature field and the generation of impurities on the edge plate.

[0061] 2) The technical solution provided in this embodiment of the invention, based on photopolymerization laser forming technology and gel casting technology, discloses a precise manufacturing method for hollow turbine blades with controllable impurities and anti-deformation. Compared with traditional investment casting, this invention utilizes the speed of photopolymerization laser forming to perform multiple anti-deformation iterations in a short time to achieve the optimal surface accuracy requirements for hollow turbine blade casting. Furthermore, addressing the issue that the shell formation in traditional investment casting is uncontrollable and easily leads to poor surface accuracy of the formed turbine blade, this embodiment of the invention designs a honeycomb structure for the resin shell of the master mold. This allows for precise control of the shell wall thickness and the preparation of shells with variable porosity, enabling accurate control of the temperature field during turbine blade casting and eliminating the generation of impurities. Moreover, this embodiment of the invention allows for the direct formation of film pores on the blade through photopolymerization laser rapid forming. With debinding and sintering, the core and shell are connected by film pore columns, allowing for direct formation of film pores during metal casting. Simultaneously, it prevents creep of the core in the molten metal, which could lead to turbine blade misalignment.

[0062] This invention provides a specific and exemplary method for precisely manufacturing hollow turbine blades with controllable heterogeneous grains and reverse deformation, comprising the following steps:

[0063] 1) Scan the prepared turbine blades using a 3D scanning device, compare the scanned blade data with the original blade model to obtain the blade deformation law, analyze the blade deformation deviation, design the 3D model of the blade after reverse deformation and the 3D model of the core-shell integrated casting mold, with a shell thickness of 2mm to 8mm.

[0064] 2) Based on the location where impurities are likely to form and thermodynamic simulation analysis, a resin master mold capable of realizing the honeycomb structure and blades of the variable porosity shell 7 was designed.

[0065] 3) The resin master mold is printed using a photopolymerization laser molding method;

[0066] 4) Prepare ceramic slurry. The matrix components of the ceramic slurry are alumina, silicon dioxide, silicon carbide, etc.; the mineralizers are yttrium oxide, aluminum silicon, zirconium oxide, etc. The ceramic matrix powder with a particle size of 2-100 μm is selected, and the powder ratio is calculated by particle size distribution method. In this embodiment of the invention, 25 wt% of 100 μm alumina, 20 wt% of 40 μm alumina, 15 wt% of 5 μm alumina, 30 wt% of 2 μm alumina, 5% of 40 μm zirconium oxide, and 5% of 40 μm aluminum silicon are used. Zirconium oxide and aluminum silicon are mineralizers. A certain proportion of premixed liquid is added to the ceramic powder, placed in a ball mill jar, and ball milled to obtain a uniformly dispersed ceramic slurry with a flowability of less than 1 Pa·s.

[0067] 5) Add the catalyst and initiator to the prepared ceramic slurry respectively, and inject it into the resin master mold under a vacuum environment with a vacuum degree of -0.08Mpa. After standing for 30 minutes, the ceramic slurry solidifies to obtain a core-shell integrated casting green mold.

[0068] 6) The obtained ceramic green body is freeze-dried, degreased, impregnated and finally fired, and then cast into an integrated core and shell mold;

[0069] 7) The core-shell integrated mold is placed in a directional solidification furnace. High-temperature alloy is poured into the core-shell integrated mold using directional solidification technology at a pouring temperature of 1550℃. After being pulled at 5.5mm / min, a metal casting is obtained. Finally, the desired single-crystal hollow turbine blade is obtained through post-processing methods such as machining, grinding, and polishing.

[0070] In summary, the technical solution provided by this invention, based on photopolymerization laser forming technology and gel casting technology, performs multiple reverse deformation iterations on the hollow turbine blades to be manufactured, in order to achieve the optimal surface accuracy requirements for hollow turbine blade casting. Addressing the issue that traditional investment casting's slurry shell preparation is uncontrollable and easily leads to poor surface accuracy of the formed turbine blades, this invention, by designing a honeycomb structure for the resin shell of the master mold and the cavity gaps, can precisely control the shell wall thickness and achieve the preparation of shells with variable porosity. It can accurately control the temperature field during turbine blade casting, eliminating the generation of impurities. Photopolymerization laser rapid forming allows for the direct formation of film pores on the blade. With debinding and sintering, the core and shell are connected by film pore columns, allowing for direct formation of film pores during metal casting. Simultaneously, it prevents core creep in the molten metal from causing turbine blade eccentricity, thus achieving precise manufacturing of hollow turbine blades.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for manufacturing hollow turbine blades with controllable heterogeneous crystals and reverse deformation, characterized in that, Includes the following steps: Step 1: Based on the original design model of the hollow turbine blade and its deformation law, obtain the three-dimensional model of the blade after inverse deformation; Step 2: Based on the three-dimensional model of the blade after the reverse deformation, obtain the three-dimensional model of the core and shell integrated casting mold; wherein, the three-dimensional model of the core and shell integrated casting mold includes a core (6) and a shell (7); the core (6) and the shell (7) are connected by a gas film pore column (8), and a part of the shell (7) is a variable porosity shell (9). Step 3: Based on the integrated core and shell casting three-dimensional model, the integrated core and shell casting master mold is prepared by photopolymerization laser forming technology; Step 4: Inject ceramic slurry into the cavity of the integrated core and shell casting master mold to form an integrated core and shell casting green blank; after the ceramic slurry crosslinks and solidifies, freeze-dry, degrease, and sinter the integrated core and shell casting green blank to obtain an integrated core and shell casting mold. Step 5: Based on the integrated core and shell mold, hollow turbine blades are prepared by directional solidification technology; In step 2, the step of obtaining the three-dimensional model of the core-shell integrated casting mold based on the three-dimensional model of the blade after the reverse deformation specifically includes: obtaining the resin master mold and gating system based on the three-dimensional model of the blade after the reverse deformation; wherein, the resin master mold includes a blade resin model (1) and a resin shell (2); the blade resin model (1) is obtained according to the three-dimensional model of the blade after the reverse deformation, the resin shell (2) is a conformal structure of the three-dimensional model of the blade after the reverse deformation, the blade resin model (1) is set inside the resin shell (2), the blade resin model (1) and the resin shell (2) form a shell cavity (3), and the interior of the blade resin model (1) forms a core cavity (4); the inner wall of the resin shell (2) is provided with multiple honeycomb structure units of different diameters and thicknesses for burning to form a variable porosity shell; the blade resin model (1) is formed with air film holes (5); and the three-dimensional model of the core-shell integrated casting mold is obtained based on the resin master mold and the gating system.

2. The method for manufacturing a hollow turbine blade with controllable heterogeneous crystals and reverse deformation according to claim 1, characterized in that, Step 1, the steps for obtaining the deformation pattern include: Based on the original design model of the hollow turbine blade, turbine blade samples were prepared using a directional solidification process. The turbine blade sample was scanned using a 3D scanning device to obtain sample blade data; The deformation pattern was obtained by comparing the sample blade data with the original design model data of the hollow turbine blade.

3. The method for manufacturing a hollow turbine blade with controllable heterogeneous crystals and reverse deformation according to claim 1, characterized in that, Step 1, specifically the steps for obtaining the 3D model of the blade after inverse deformation, include: Based on the deformation law, the displacement field deviation is obtained; The blade's three-dimensional model after inverse deformation is obtained by inverse solution based on displacement field deviation.

4. The method for manufacturing a hollow turbine blade with controllable heterogeneous crystals and reverse deformation according to claim 1, characterized in that, The diameter of the air film pore (5) is greater than or equal to 0.4 mm.

5. The method for manufacturing a hollow turbine blade with controllable heterogeneous crystals and reverse deformation according to claim 1, characterized in that, The diameter of a single honeycomb structural unit varies from 0.1 mm to 0.5 mm.

6. The method for manufacturing a hollow turbine blade with controllable heterogeneous crystals and reverse deformation according to claim 1, characterized in that, The thickness of the honeycomb structure unit varies within a range of less than or equal to 3 mm.

7. The method for manufacturing a hollow turbine blade with controllable heterogeneous crystals and reverse deformation according to claim 1, characterized in that, The shell thickness of the integrated core and shell mold is 2mm to 8mm.

8. The method for manufacturing a hollow turbine blade with controllable heterogeneous crystals and reverse deformation according to claim 1, characterized in that, The ceramic slurry contains a sintering expansion agent.

9. The method for manufacturing a hollow turbine blade with controllable heterogeneous crystals and reverse deformation according to claim 8, characterized in that, The matrix material of the ceramic slurry is alumina, silicon oxide, or silicon carbide; The sintering expansion agent is aluminum silicon, aluminum powder, yttrium oxide, or silicon powder.

Images