Design method for heat preservation patching of special-shaped complex thin-wall integral precision casting

Abstract

The invention discloses a special-shaped complex thin-wall integral precision casting heat preservation patch design method in the technical field of precision casting, which comprises the following steps of: accurately and orderly controlling a temperature field in a forming process of a high-integration special-shaped complex thin-wall integral precision casting by designing a high-adaptation asbestos heat preservation patch; sequential solidification from the special-shaped complex thin wall to the riser and efficient feeding of the riser to the special-shaped complex thin wall are achieved, the problem of looseness of the special-shaped complex thin wall is effectively solved, an accurate simulation boundary condition database of the special-shaped complex thin wall is established through temperature measurement test and simulation software reverse calculation, traditional experience trial and error and extensive process design are broken through, and the accuracy of the special-shaped complex thin wall is improved. According to the method, the forward and lean process design based on precise simulation is achieved, lean production of high-integration special-shaped complex thin-wall integral precision castings is achieved, the product quality is effectively improved, the development period is greatly shortened, and the production cost is greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of precision casting, and particularly to a design method for heat preservation padding of a special-shaped complex thin-walled integral precision casting. Background Art

[0002] With the continuous development of modern advanced aero-engines towards functional integration and thin-walled lightweight, the forming method of precision structural parts has changed from traditional segmented sheet metal stamping and step-by-step welding processes to integral precision casting. In the precision casting process, high-integration integral precision castings are usually attached with many functional components such as special-shaped pipelines and variable-section positioning small bosses on the thin-walled matrix. The structure is extremely complex and the casting processability is poor. As Figure 1-2 shown, the main process difficulties are as follows:

[0003] 1. High requirements for tissue density. The special-shaped complex thin-walled cavities of aero-engine precision castings need to withstand high pressure and temperature while ensuring the overall structural strength. To meet the requirements of structural strength and airtightness, strict control is exerted over the defects of loose thin-walled tissues.

[0004] 2. Prone to metallurgical porosity defects. The special-shaped thin-walled structure is complex, with irregular wall thickness changes, resulting in a chaotic solidification temperature field and large differences in solidification shrinkage. It is difficult to achieve sequential solidification and feeding, and porosity defects are prone to occur at the heat joints of pipelines, small bosses with wall thickness changes, and thin-walled corners.

[0005] 3. Difficult process design. Most special-shaped complex thin-walled castings are formed by net shape without machining allowance. Not only can't they be formed according to the principle of simultaneous solidification like conventional simple thin-walled castings, but it is also difficult to set risers when forming according to the principle of sequential solidification. In addition, due to the mutual coupling influence of the temperature fields of each characteristic part of the special-shaped complex thin wall, when using the conventional empirical method for process design, the trial-and-error method has high costs and a long cycle, and it is difficult to achieve precise and orderly control of the solidification temperature field, with poor applicability.

[0006] For conventional thin-walled castings with small solidification shrinkage differences, the prior art usually forms them according to the principle of simultaneous solidification, while for complex thin-walled castings, it mainly promotes their sequential solidification through the pressure regulating casting process (Publication No.: CN102699311A, "Precision Casting Method for Superalloy Complex Thin-Walled Castings"), and uses hot isostatic pressing technology to perform hot densification treatment on the castings (Publication No.: US4582681A, "Method and apparatus for hot isostatic pressing"). However, the prior art has the following deficiencies for forming the special-shaped complex thin walls of high-integration integral precision castings:

[0007] 1. Although the precision investment casting process for superalloys can play a good role in promoting the steady filling of molten metal and improving the solidification feeding capacity through precise pressure regulation, it is difficult to precisely and orderly regulate the solidification temperature field, and the effect of promoting the sequential solidification of castings is not good. In addition, since the shell strength requirements of the precision investment casting process for superalloys are much higher than those of gravity vacuum casting, it is necessary to increase the shell thickness to improve the shell strength under the existing mature shell preparation system, which will reduce the solidification rate of molten metal and increase the risk of porosity in castings.

[0008] 2. The hot isostatic pressing technology is difficult to densify the superficial porosity defects formed on the surface of castings, and it is easy to cause dimensional deformation of castings during the hot high-pressure densification process.

[0009] 3. The precision investment casting and hot isostatic pressing technology for superalloys and their manufacturing equipment have been blocked by foreign countries for a long time. At present, there is no mature and perfect engineering application process design database in China. The process equipment is expensive, and the process control is strict, making it difficult to form a greater advantage in the highly competitive market.

[0010] Based on this, the present invention designs a method for designing heat preservation and feeding for special-shaped complex thin-walled integral precision castings to solve the above problems. Summary of the Invention

[0011] To achieve the above object, the present invention provides the following technical solution: A method for designing heat preservation and feeding for special-shaped complex thin-walled integral precision castings, characterized by comprising the following steps:

[0012] S1, Selecting characteristic points: Select characteristic points on the casting, and the characteristic points are the parts that will cause differences in the heat dissipation environment of molten metal during the pouring process;

[0013] S2, Temperature measurement experiment: Conduct a temperature measurement experiment on the casting process to obtain the temperature-time change curves of the characteristic points under the conditions of an empty shell and different thicknesses of heat preservation and feeding, and obtain the actual temperature field distribution during the casting process;

[0014] S3, Establishing a precise simulation boundary condition database: Taking the temperature-time change curve of the characteristic points as the constraint condition, using casting simulation software to carry out simulation inverse calculation of the interfacial heat transfer coefficient under the conditions of an empty shell and different thicknesses of heat preservation and feeding, and continuously iterating according to the comparison results between the actually measured temperature field of the characteristic points and the temperature field simulated and calculated by the casting simulation software to obtain a precise simulation boundary condition database that matches the actually measured temperature field;

[0015] S4, Forward design of heat preservation and feeding: Design the heat preservation and feeding according to the precise simulation boundary condition database and the solidification sequence required during the casting of the casting to obtain high-adaptability heat preservation and feeding process parameters.

[0016] As a further solution of the present invention, the following steps are further included:

[0017] S5, pouring verification: According to the high - adaptability insulation pad process parameters obtained by forward design of the insulation pad, wrap the insulation pad on the surface of the casting shell, and carry out actual pouring. During pouring, also monitor the temperature of the characteristic points to obtain the temperature - time change curve during the casting process and the actual poured casting, and verify the accuracy of the accurate simulation boundary condition database and the reliability of the high - adaptability insulation pad process parameters;

[0018] S6, result comparison and analysis: Compare the temperature field of the characteristic points and the porosity quality of the physical object during the casting process in S5 with the temperature field and porosity results simulated according to the high - adaptability insulation pad to judge whether the actual pouring verification results are consistent with the simulation results;

[0019] If the results are consistent, the design of the insulation pad is completed;

[0020] If the results are not consistent, correct the simulation boundary condition database according to the temperature - time change curve of the characteristic points after wrapping the high - adaptability insulation pad, and optimize the high - adaptability insulation pad process parameters through the corrected simulation boundary condition database.

[0021] As a further solution of the present invention, in step S2, when carrying out the temperature measurement test of the casting process, adopt the actual casting process of the casting, and record the temperature change of the characteristic points during the period from the casting shell being baked out of the furnace to the completion of the solidification of the molten metal.

[0022] As a further solution of the present invention, in step S2, when carrying out the temperature measurement test of the casting process, place the temperature measurement sensor at the corresponding characteristic point position inside the shell during the production process of the casting shell.

[0023] As a further solution of the present invention, in step S3, the accurate simulation boundary condition database includes the boundary heat transfer coefficients of different temperature measurement points under the boundary conditions of insulation pads with different thicknesses.

[0024] As a further solution of the present invention, in step S4, the solidification sequence required during the casting of the casting includes:

[0025] Vertically, achieve the sequential solidification from the bottom end of the casting to the top riser;

[0026] Horizontally, achieve the solidification of the inner and outer walls with the grains growing from the two - side fine - grain zones to the inside.

[0027] As a further solution of the present invention, in step S4, the high - adaptability insulation pad process parameters include the thickness, shape and wrapping position of the insulation pad.

[0028] As a further solution of the present invention, in step S5, when wrapping the heat-insulating pad on the surface of the casting shell, first make a heat-insulating pad with a corresponding thickness and shape according to the high-adaptability heat-insulating pad process parameters obtained in step S4, and the material of the heat-insulating pad is the same as that of the heat-insulating pad used in the temperature measurement test in step S2. Then wrap the casting shell at the wrapping position required by the high-adaptability heat-insulating pad process parameters.

[0029] The present invention has the following beneficial effects:

[0030] 1. By designing a high-adaptability asbestos heat-insulating pad, the temperature field during the forming process of the highly integrated, abnormally shaped, complex, thin-walled integral precision casting is accurately and orderly controlled, realizing the sequential solidification from the abnormally shaped, complex, thin-walled part to the riser and the efficient feeding of the riser to the abnormally shaped, complex, thin-walled part, effectively solving the problem of porosity in the abnormally shaped, complex, thin-walled part.

[0031] 2. By establishing a precise simulation boundary condition database for the abnormally shaped, complex, thin-walled part through temperature measurement tests and inverse calculation using simulation software, breaking through the traditional empirical trial-and-error and extensive process design, realizing the forward and lean process design based on precise simulation, which is conducive to the lean production of the highly integrated, abnormally shaped, complex, thin-walled integral precision casting. While effectively improving the product quality, it greatly shortens the development cycle and reduces the production cost.

[0032] In addition to the purposes, features and advantages described above, the present invention has other purposes, features and advantages. The present invention will be further described in detail below with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0034] Figure 1 It is a schematic structural diagram of a highly integrated, abnormally shaped, complex, thin-walled integral precision casting.

[0035] Figure 2 It is a schematic cross-sectional view of a highly integrated, abnormally shaped, complex, thin-walled integral precision casting.

[0036] Figure 3 It is a schematic diagram of the selection of characteristic points in the present invention.

[0037] Figure 4 It is a schematic diagram of the direction of sequential solidification in the present invention.

[0038] Figure 5 It is a schematic diagram of the shell wrapped with a high-adaptability heat-insulating pad in the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways defined and covered by the following.

[0040] Please refer to Figure 1-5 , the present invention provides a technical solution: a design method for thermal insulation patches of special-shaped complex thin-walled integral precision castings, including the following steps:

[0041] S1, Select characteristic points: Select characteristic points on the casting. The characteristic points are the parts that will cause differences in the heat dissipation environment of the molten metal during the casting process;

[0042] As Figure 3 shown, the characteristic points are selected at the wall thickness difference parts, boss structure parts and groove parts. In the figure, the characteristic points 1, 3, 4 are the wall thickness difference parts, and the characteristic point 2 in the figure is the groove part;

[0043] For the wall thickness difference parts and boss structure parts, different wall thicknesses result in different heat dissipation environments of the molten metal during casting. The thicker wall parts carry more energy of the molten metal during casting, and at the same time, the heat dissipation is radiative heat dissipation from the inside to the outside. Therefore, there are differences in the heat dissipation speed at different wall thickness positions. Thus, it is necessary to select the wall thickness difference parts and boss structure parts as characteristic points.

[0044] For the groove parts, as Figure 5 shown, during the shell-making process of the groove parts, the shells inside the groove parts may be adjacent, which will cause the thickness of the groove parts on the shell to be much larger than that of other parts, resulting in poor heat dissipation effect of the molten metal at the groove parts during casting. Thus, it is necessary to select the groove parts as characteristic points;

[0045] Due to the diversity of the shape or surface characteristics of the casting, in addition to the characteristic point selection parts mentioned above, for other positions that will cause differences in the heat dissipation environment of the molten metal, they can all be selected as characteristic points;

[0046] At the same time, as Figure 3 shown, when selecting characteristic points, the casting can be split into several vertical sections, and the characteristic points should be selected on the same vertical section of the casting as much as possible, so as to more intuitively understand the influence of different characteristic points on the temperature field distribution of the molten metal during the casting process.

[0047] S2, Temperature measurement test: Conduct a temperature measurement test on the casting process to obtain the curves of temperature change with time at the characteristic points under the conditions of an empty shell and different thicknesses of thermal insulation patches, and obtain the actual temperature field distribution during the casting process. By conducting a temperature measurement test on the casting process, the true temperature change curve and temperature field distribution of the characteristic points of the casting during the casting process can be obtained, providing a basis for establishing an accurate simulation boundary condition database in the follow-up;

[0048] S3. Establish a precise simulation boundary condition database: Use the curve of the characteristic point temperature varying with time as the constraint condition, and adopt casting simulation software to carry out the simulation inverse calculation of the interface heat transfer coefficient under the conditions of an empty shell and different thicknesses of thermal insulation patches. According to the comparison results between the actually measured temperature field of the characteristic points and the temperature field simulated and calculated by the casting simulation software, continuously iterate to obtain a precise simulation boundary condition database that matches the actually measured temperature field;

[0049] Specifically, the precise simulation boundary condition database contains the boundary heat transfer coefficients of different temperature measurement points under the boundary conditions of different thicknesses of thermal insulation patches, which is used to provide a basis for the subsequent forward design of thermal insulation patches;

[0050] The casting simulation software can adopt ProCAST, and the software is equipped with a module for the simulation inverse calculation of the heat transfer coefficient, which belongs to the conventional technical means in this field and will not be elaborated here.

[0051] S4. Forward design of thermal insulation patches: Design the thermal insulation patches according to the precise simulation boundary condition database and the solidification sequence required during the casting of the casting to obtain the process parameters of the highly adaptable thermal insulation patches;

[0052] First of all, we need to design the boundary heat transfer coefficients of different characteristic points of the casting according to the required solidification sequence of the casting. Subsequently, through the data in the precise simulation boundary condition database, the thickness of the thermal insulation patches required for different characteristic points can be obtained. Thus, a highly adaptable thermal insulation patch can be designed, and the process parameters of the highly adaptable thermal insulation patch can be obtained.

[0053] This method selects characteristic points on the casting, then conducts a temperature measurement experiment during the casting process to obtain the curve of the temperature varying with time and the temperature field distribution of the characteristic points under the conditions of an empty shell and different thicknesses of thermal insulation patches, which can more intuitively understand the heat dissipation environment of different characteristic points and the differences in the heat dissipation environment between different characteristic points. At the same time, using the curve of the characteristic point temperature varying with time as the constraint condition, adopt casting simulation software to carry out the simulation inverse calculation of the interface heat transfer coefficient of the characteristic points under the conditions of an empty shell and different thicknesses of thermal insulation patches to obtain a precise simulation boundary condition database. Through the precise simulation boundary condition database, the boundary heat transfer coefficients of different characteristic points under the boundary conditions of an empty shell and different thicknesses of wrapped thermal insulation patches can be intuitively understood, breaking through the traditional empirical trial and error and extensive process design, realizing precise forward and lean process design based on simulation, being conducive to realizing the lean production of highly integrated special-shaped complex thin-walled integral precision castings, effectively improving the product quality while significantly shortening the development cycle and reducing the production cost;

[0054] Based on the solidification sequence required during the casting of the casting, the positive design of the insulation feeder can be carried out through the accurate simulation boundary condition database to obtain the process parameters of the highly adaptable insulation feeder, precisely and orderly control the temperature field during the forming process of the highly integrated, irregular, complex, thin-walled integral precision casting, realize the sequential solidification from the irregular, complex, thin-walled part to the riser, and the efficient feeding of the riser to the irregular, complex, thin-walled part, effectively solving the problem of porosity in the irregular, complex, thin-walled part.

[0055] After obtaining the process parameters of the highly adaptable insulation feeder, it is necessary to conduct a pouring verification, and the verification method is as follows:

[0056] S5, Pouring verification: According to the process parameters of the highly adaptable insulation feeder obtained from the positive design of the insulation feeder, wrap the highly adaptable insulation feeder on the surface of the casting shell, and carry out actual pouring. During pouring, also monitor the temperature of the characteristic points to obtain the temperature-time change curve during the casting process and the physical casting, so as to verify the accuracy of the accurate simulation boundary condition database and the reliability of the process parameters of the highly adaptable insulation feeder;

[0057] S6, Result comparison and analysis: Compare the temperature field of the characteristic points and the porosity quality of the physical object during the casting process in S5 with the temperature field and porosity results simulated according to the highly adaptable insulation feeder to judge whether the actual pouring verification result is consistent with the simulation result;

[0058] Wrap the highly adaptable insulation feeder on the surface of the casting shell according to the process parameters of the highly adaptable insulation feeder, and then carry out actual pouring. In this way, the temperature-time change curve of the characteristic points and the temperature field distribution after wrapping the highly adaptable insulation feeder can be obtained, and the physical casting can be obtained. Subsequently, compare the temperature field distribution of the characteristic points and the porosity quality of the physical object during the actual pouring process in S5 with the temperature field and porosity results obtained from the simulation calculation according to the highly adaptable insulation feeder to judge whether the actual pouring verification result is consistent with the simulation result. When the results are consistent, the design of the insulation feeder is completed. When the results are inconsistent, it is necessary to correct the simulation boundary condition database according to the temperature-time change curve of the characteristic points after wrapping the highly adaptable insulation feeder, and optimize the process parameters of the highly adaptable insulation feeder through the corrected simulation boundary condition database. After optimization, repeat steps S5 and S6 until the actual pouring verification result is consistent with the simulation result. Through step S5, it can be verified whether the highly adaptable insulation feeder can achieve the results required when designing the highly adaptable insulation feeder, and when the results are inconsistent, use the temperature-time change curve of the characteristic points after wrapping the highly adaptable insulation feeder obtained in S5 to correct the simulation boundary condition database to ensure the reliability of the highly adaptable insulation feeder.

[0059] Specifically, in step S2, when conducting the temperature measurement test during the casting process, the actual casting process of the casting is adopted, and the temperature changes of the characteristic points are recorded during the period from when the mold shell of the casting is baked and taken out of the furnace to when the molten metal solidifies completely.

[0060] Adopting the actual casting process of the casting can make the finally obtained temperature-time change curve more in line with the actual situation. At the same time, it makes the subsequently established accurate simulation boundary condition database more accurate, makes the highly adaptable thermal insulation allowance designed according to the accurate simulation boundary condition database more reliable. At the same time, by selecting the temperature changes of the characteristic points during the period from when the mold shell of the actual casting process is baked and taken out of the furnace to when the molten metal solidifies completely, the temperature-time change curve is more perfect, including the influence of the mold shell temperature on the solidification sequence of the molten metal.

[0061] Specifically, in step S2, when conducting the temperature measurement test during the casting process, the temperature measurement sensor is placed inside the mold shell at the corresponding characteristic point positions during the production process of the casting mold shell of the casting. When installing the temperature measurement sensor inside the mold shell, temperature measurement sensors need to be set on both the inner and outer sides of the mold shell at the characteristic points. During the temperature measurement test, the complete temperature change curve of the characteristic points needs to be recorded. Therefore, temperature measurement sensors need to be installed at the characteristic points. To ensure the accuracy of the temperature measurement of the temperature measurement sensor and prevent the temperature measurement sensor from moving, the temperature measurement sensor is placed inside the mold shell at the corresponding characteristic point positions during the production of the casting mold shell. The temperature measurement sensor is wrapped by the mold shell, and the position of the temperature measurement sensor is fixed after the mold shell solidifies. In this way, the temperature measurement sensor can be closer to the characteristic point, and at the same time, it is ensured that the position of the temperature measurement sensor will not move after the mold shell solidifies, improving the accuracy of temperature measurement.

[0062] Specifically, in step S4, the required solidification sequence during the casting of the casting includes:

[0063] Vertically, sequential solidification from the bottom end to the top riser of the casting is achieved. As Figure 4 shown, under normal circumstances, the molten metal entering the mold shell from the top riser will solidify sequentially from bottom to top according to the order of entry into the mold shell. However, when there are parts on the casting that affect the heat dissipation environment, such as parts with wall thickness differences, boss structures, and groove parts, it will cause the solidification sequence of the molten metal to be disordered, affecting the quality of the finally formed casting. Therefore, it is necessary to design a highly adaptable thermal insulation allowance based on the interfacial heat transfer coefficient of different characteristic points on the casting in the empty mold shell state in the vertical direction, combined with the interfacial heat transfer coefficient of different characteristic points under different thickness thermal insulation allowance conditions, to obtain the process parameters of the highly adaptable thermal insulation allowance, so that the mold shell wrapped with the highly adaptable thermal insulation allowance can achieve sequential solidification from the bottom end to the top riser of the casting, forming a shrinkage compensation channel expansion angle, enabling the molten metal to efficiently compensate for the special-shaped complex thin walls through the wedge-shaped shrinkage compensation channel, and avoiding the generation of internal porosity.

[0064] Horizontally, the grains of the inner and outer walls grow and solidify from the fine-grained zones on both sides towards the interior. As Figure 4 shown, based on the interfacial heat transfer coefficients of the same characteristic points on both sides of the casting in the horizontal direction under the condition of the empty shell, combined with the interfacial heat transfer coefficients under different thicknesses of thermal insulation pads, a highly adaptable thermal insulation pad is designed to obtain the process parameters of the highly adaptable thermal insulation pad, enabling the liquid metal grains to grow and solidify from the fine-grained zones on both sides towards the interior, weakening the growth trend of the grains from the outer wall with a high heat transfer coefficient to the inner wall with a low heat transfer coefficient, causing the grains growing from the inner and outer walls to intersect inside the casting, and avoiding the occurrence of superficial porosity on the inner wall.

[0065] Specifically, the process parameters of the highly adaptable thermal insulation pad include the thickness, shape, and wrapping position of the thermal insulation pad;

[0066] When designing the highly adaptable thermal insulation pad, it is necessary to wrap thermal insulation pads with different thicknesses at different positions on the surface of the mold shell according to the required solidification sequence of the casting, so as to form thermal insulation pads with different shapes and different regional thicknesses, realizing the high-precision control of the temperature field of the molten metal during pouring and the high-precision control of the solidification sequence, breaking through the traditional empirical trial and error and extensive process design, achieving the accurate forward simulation-based and lean process design, being conducive to the lean production of highly integrated special-shaped complex thin-walled integral precision castings, effectively improving the product quality while significantly shortening the development cycle and reducing the production cost.

[0067] Specifically, in step S5, when wrapping the thermal insulation pad on the surface of the casting mold shell, first, a thermal insulation pad with the corresponding thickness and shape is made according to the process parameters of the highly adaptable thermal insulation pad obtained in step S4, and the material of the thermal insulation pad is the same as that used in the thermal insulation pad for the temperature measurement test in step S2. Subsequently, the casting mold shell is wrapped according to the wrapping position required by the process parameters of the highly adaptable thermal insulation pad.

[0068] Before wrapping the thermal insulation pad, it is necessary to first make a thermal insulation pad with the corresponding thickness and shape according to the process parameters of the highly adaptable thermal insulation pad, and the material of the thermal insulation pad is the same as that used in the thermal insulation pad for the temperature measurement test in step S2, so as to ensure that the made highly adaptable thermal insulation pad conforms to the simulation results.

[0069] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A design method for thermal insulation patch of special-shaped complex thin-walled integral precision casting, characterized in that: The following steps are involved: S1, select feature points: select feature points on the casting, which are the parts that will cause differences in the heat dissipation environment of the molten metal during the pouring process; S2, temperature measurement test: Carry out temperature measurement test during the casting process, obtain the temperature change curve of the characteristic point under the conditions of empty shell and different thickness insulation subsidy over time, and obtain the actual temperature field distribution during the casting process; S3, establish a precise simulation boundary condition database: take the curve of characteristic point temperature changing with time as the constraint condition, use casting simulation software to carry out simulation inverse calculation of interface heat transfer coefficient under the conditions of empty shell and different thickness insulation subsidy, and compare the actual measured characteristic point temperature field with the casting simulation software simulation calculation temperature field, continuously iterate, and obtain a precise simulation boundary condition database matching the actual measured temperature field; S4, forward design of thermal insulation subsidy: design the thermal insulation subsidy according to the precise simulation boundary condition database and the solidification sequence required during casting to obtain highly adaptable thermal insulation subsidy process parameters.

2. The method for designing thermal insulation patch for special-shaped complex thin-walled integral precision casting according to claim 1, characterized in that: The following steps are also included: S5, pouring verification: According to the highly adaptable insulation subsidy process parameters obtained by the forward design of the insulation subsidy, the insulation subsidy is wrapped on the surface of the casting shell, and actual pouring is carried out. During the pouring, the temperature of the characteristic points is also monitored to obtain the temperature change curve over time during the casting process and the actual casting, and verify the accuracy of the precise simulation boundary condition database and the reliability of the highly adaptable insulation subsidy process parameters; S6, result comparison and analysis: compare the temperature field and the actual porosity quality of the characteristic points of the casting process in S5 with the temperature field and porosity results simulated according to the high-adaptation insulation subsidy to determine whether the actual casting verification results are consistent with the simulation results; When the results match, the insulation subsidy design is complete; When the results do not match, the simulation boundary condition database is corrected according to the temperature change curve of the characteristic point after wrapping the high-fit thermal insulation subsidy, and the high-fit thermal insulation subsidy process parameters are optimized through the corrected simulation boundary condition database.

3. The method for designing thermal insulation patch for special-shaped complex thin-walled integral precision casting according to claim 1, characterized in that: In step S2, when conducting a temperature measurement test of the casting process, the actual casting process of the casting is used to record the temperature changes of characteristic points during the period from when the casting shell is baked out of the furnace to when the molten metal solidifies.

4. The method for designing thermal insulation patch for special-shaped complex thin-walled integral precision casting according to claim 1, characterized in that: In step S2, when conducting a temperature measurement test during the casting process, a temperature sensor is placed at a corresponding characteristic point position in the shell during the production process of the casting shell.

5. The method for designing thermal insulation patch for special-shaped complex thin-walled integral precision casting according to claim 1, characterized in that: In step S3, the precise simulation boundary condition database includes boundary heat transfer coefficients of different temperature measurement points under boundary conditions of thermal insulation subsidies of different thicknesses.

6. The method for designing thermal insulation patch for special-shaped complex thin-walled integral precision casting according to claim 1, characterized in that: In step S4, the solidification sequence required for casting includes: In the vertical direction, sequential solidification is achieved from the bottom of the casting to the top riser; In the horizontal direction, the grains on the inner and outer walls grow and solidify from the fine grain areas on both sides to the inside.

7. The method for designing thermal insulation patch for special-shaped complex thin-walled integral precision casting according to claim 1, characterized in that: In step S4, the process parameters of the highly adaptable thermal insulation patch include the thickness, shape and wrapping position of the thermal insulation patch.

8. The method for designing thermal insulation patch for special-shaped complex thin-walled integral precision casting according to claim 2, characterized in that: In step S5, when wrapping the thermal insulation subsidy on the surface of the casting shell, first, the thermal insulation subsidy of corresponding thickness and shape is made according to the high-fit thermal insulation subsidy process parameters obtained in step S4, and the thermal insulation subsidy material is consistent with the thermal insulation subsidy material used in the temperature measurement test in step S2. Then, the casting shell is wrapped according to the wrapping position required by the high-fit thermal insulation subsidy process parameters.

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