Single-crystal large-size blade wax mold tree position control process and application

Abstract

The invention relates to the field of investment casting, and particularly discloses a single-crystal large-size blade wax mold assembly position control process and application, and the assembly position control process comprises the following steps: preassembling a spiral crystal selector, preparing a wax mold welding environment, setting an alloy structure assembly system, and bonding a seeding section and a seeding rod. According to the method, the tree assembling system with enough rigidity strength is adopted, the position of the blade is accurately determined by means of the limiting tool, the accuracy of the tree assembling position is improved, the consistency of the tree assembling height is guaranteed, and the tree assembling efficiency is improved. The problem that the tree assembling position is changed due to uneven stress in the shell manufacturing process is solved, the stress uniformity and the tree assembling stability in the shell manufacturing process are improved, it is ensured that the temperature gradient of a casting is uniform, the problems that a pasty area is unstable and the casting deforms or cracks due to inconsistent temperature fields are solved, and the quality stability of the casting is improved.

Description

Technical Field

[0001] This invention relates to the field of investment casting, specifically to a process and application for controlling the position of a single-crystal large-size blade wax model assembly. Background Technology

[0002] In aerospace and energy fields, the demand for high-performance engines continues to drive innovation in the manufacturing technology of key components. As a core component of the engine's hot end, the manufacturing precision and quality of single-crystal large-size blades are directly related to the engine's performance, reliability and service life. Investment casting has become the mainstream method for preparing single-crystal large-size blades due to its advantage of being able to manufacture complex-shaped and high-precision parts. The wax pattern assembly process occupies a fundamental and extremely critical position in the entire investment casting process.

[0003] From the perspective of aero-engine operation requirements, it must stably output powerful thrust under stringent quality and volume constraints, while ensuring reliable operation over long periods and achieving flexible and precise performance control. This places extremely high demands on engine design and manufacturing processes. In the field of ground-based gas turbines, to adapt to extreme service environments, the core high-temperature component, turbine blades, has gradually upgraded from equiaxed crystals to hollow oriented columnar crystals and even single-crystal blades. Taking heavy-duty gas turbines as an example, their large-sized blades typically have characteristics such as no margin in the blade body, a length greater than 300mm, a weight exceeding 10kg, and complex internal cavity structures, significantly increasing the difficulty of manufacturing processes. Against this backdrop, in the process of manufacturing aero-engine blades using investment casting, the large-module directional solidification preparation technology has emerged. This technology uses a single module, a single shell, and a single crucible to cast the blade in one go. This not only achieves the same process for manufacturing the entire batch of blades, ensuring the consistency of quality within the same batch, but also significantly improves the product yield. However, with the increase in blade size and the increasing complexity of module structures, the challenge of controlling the position of the wax model assembly tree has become increasingly prominent.

[0004] Currently, in the process of building wax modules for large-size monocrystalline blades, there are many problems that affect blade quality and production efficiency: 1. High reliance on manual labor, resulting in low consistency and efficiency: Traditional tree assembly methods heavily rely on manual operation, which is not only inefficient but also makes it difficult to guarantee process consistency. Manual placement of wax molds can easily lead to deformation, and the position and angle during welding depend entirely on experience. Differences in the skill levels of different operators directly cause fluctuations in module quality, significantly increasing the uncertainty of subsequent processes. 2. Insufficient positional accuracy control leads to a chain of quality problems: During the assembly of the blades, it is difficult to accurately control the vertical position, relative angle, uniformity of distribution on the water-cooling plate, and perpendicularity. This can lead to asymmetrical shell shape, affect the uniformity of temperature field during casting, reduce the casting yield, and cause non-parallel connection between the crystal selector and seed crystal, resulting in a decrease in the casting grain orientation qualification rate. Furthermore, when welding the blades to the base plate, it is difficult to accurately control their perpendicularity, which further reduces the casting grain orientation qualification rate and seriously lowers the overall yield. 3. Poor adaptability and difficulty in meeting complex process requirements: As blade size increases and module structure becomes more complex, the positioning accuracy and stability of existing tree assembly schemes further decrease when dealing with large-sized, heavy, and complex internal cavity structure blades, making them unable to meet the stringent requirements of large module directional solidification preparation technology for tree assembly position control.

[0005] To address these issues, this application proposes a single-crystal large-size blade wax model tree position control process and its application. Summary of the Invention

[0006] To address the existing problems, this invention provides a process and application for controlling the position of a single-crystal large-size blade wax model tree, which can effectively solve the problems mentioned in the background art.

[0007] To solve the above problems, the present invention adopts the following technical solution: A process for controlling the position of a single-crystal large-size blade wax module tree includes the following steps: 1) Pre-assembled spiral crystal selector: Select a suitable spiral crystal selector according to the grain orientation requirements of the single crystal blade, and weld it using wax seed crystals or alloy seed crystals according to the reserved spiral crystal selector; 2) Prepare the wax model welding environment: The temperature of the wax model welding room should be 20-25℃, the humidity should be 40-60%, and the adhesive wax should be prepared at a temperature of 130-150℃. 3) Setting up the tree system: The tree system consists of three parts, from bottom to top: a waxed base plate, a waxed hard alloy central column, and a waxed pouring cup; 4) Bonding the pilot section and pilot rod: According to the process requirements, bond the pilot section to the front end of the blade body, and then bond the pilot rod from the pilot section to the blade edge plate. 5) Welding Tree System: Attach the blades with the attached accessories between the base plate and the wax pouring cup, and use a limiting fixture to position the blades. Allow the blades to cool naturally for more than 8 hours after welding. 6) Cleaning and inspecting wax trees: After the trees are assembled, clean the wax trees three times. The first time, use the prepared cleaning solution to degrease them. The second and third times, use tap water to clean them.

[0008] Preferably, in step 1), the height of the spiral crystal selector is 45mm, the angle of one turn of the selection spiral is 45°, the diameter is 5mm, and the diameter of the seed crystal is 10mm and the height is 30mm.

[0009] Preferably, in step 3), the alloy rod is fixedly connected to the center of the metal disc to form a metal assembly. The metal assembly is placed in a wax mold and wax liquid is poured in one piece. The outer surfaces of the metal disc and the alloy rod are covered with a wax layer. After demolding, a wax-coated base plate, a wax-coated hard alloy column, and a wax pouring cup are formed as an integral structure.

[0010] Preferably, in step 5), the limiting fixture is made of foam integrally processed. The limiting fixture includes a limiting plate, the limiting plate is provided with a slot for limiting the blade, the lower end of the limiting plate is provided with a semi-cylinder, the semi-cylinder and the limiting plate are provided with a limiting groove that fits with the central column along their axial direction, and the edge of the limiting plate is provided with a support column.

[0011] Preferably, the limiting plate is semi-circular, and the semi-cylinder is coaxially arranged with the limiting plate. The slot is located at the edge of the limiting plate passing through the center, forming a lateral opening slot.

[0012] Preferably, the slot on the limiting plate is located at the blade edge plate position and the inner wall contour of the slot is consistent with the contour of the blade edge plate.

[0013] Preferably, in step 5), a gating channel is connected between the pouring cup and the spiral crystal selector, and a filter is provided on the gating channel.

[0014] An application of a single-crystal large-size blade wax model tree position control process, which is used to prepare heavy-duty gas large-size hollow single-crystal blade shells.

[0015] Compared with existing technologies, the beneficial effects of this invention are as follows: By using a sufficiently rigid and strong assembly system and utilizing blade-limiting tooling to determine the precise position of the blades, the invention improves the accuracy of blade assembly, avoids displacement of the blades during assembly that affects accuracy, and utilizes highly consistent assembly to improve the uniformity of stress during shell making, ensuring stable assembly without positional changes due to uneven stress. This results in a more uniform temperature gradient in the casting, eliminating the problem of inconsistent temperature fields, preventing deformation or cracking of the casting, and solving the problem of instability in the mushy region caused by inconsistent temperature fields. It overcomes the limitations of manual operation, achieving precise and stable control of the assembly position, improving the manufacturing quality and production efficiency of high-end blades, and ensuring the accuracy and uniformity of blade angle consistency, perpendicularity, and distribution uniformity on the water-cooling plate. The final shell produced is symmetrical with a uniform temperature field distribution, greatly improving the product qualification rate, significantly reducing product manufacturing costs, optimizing the large-scale assembly production process system for heavy-duty gas turbine blades, and achieving international advanced levels in terms of comprehensive shell performance, geometric dimensions, and overall quality, enabling mass production and application. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the tree structure in a single-crystal large-size blade wax model tree positioning control process.

[0017] In the diagram: 1. Base plate; 2. Central column; 3. Sprue cup; 4. Spiral crystal selector; 5. Limiting plate; 6. Slot; 7. Semi-cylinder; 8. Support column; 9. Crystal guide section; 10. Sprue; 11. Filter; 12. Single crystal blade. Detailed Implementation

[0018] 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. Example

[0019] Combination Figure 1 This embodiment describes a process for controlling the position of a single-crystal large-size blade wax module tree, which includes the following steps: 1) Pre-assembled spiral crystal selector 4: According to the requirements of the orientation of the single crystal blade 12 grains, select a suitable spiral crystal selector 4, and weld it with wax seed crystal or alloy seed crystal according to the reserved spiral crystal selector 4. In this example, the height of the spiral crystal selector 4 is 45mm, the angle of one turn of the crystal selection spiral is 45°, the diameter is 5mm, the diameter of the seed crystal is 10mm and the height is 30mm. 2) Prepare the wax model welding environment: The temperature of the wax model welding room should be 20-25℃, the humidity should be 40-60%, and the adhesive wax should be prepared at a temperature of 130-150℃. 3) Setting up the tree system: The tree system consists of three parts, from bottom to top: a wax-coated base plate 1, a wax-coated carbide central column 2, and a wax pouring cup 3. The preparation process is as follows: the alloy rod is fixedly connected to the center of the metal disc to form a metal assembly. The metal assembly is placed in the wax mold and wax liquid is poured in as a whole. The outer surfaces of the metal disc and the alloy rod are covered with a wax layer. After demolding, a wax-coated base plate 1, a wax-coated carbide central column 2, and a wax pouring cup 3 are formed as an integral structure. The metal disc is an aluminum disc with a diameter of 600mm. The center of the aluminum disc has a 40mm threaded hole. The alloy rod is a carbide threaded rod. The alloy rod is threaded and fixed to the threaded hole of the aluminum disc. The wax coating thickness of the alloy rod is 6mm and the wax coating height is 600mm. The pouring cup 3 is a conical pouring cup with a bottom diameter of 150mm, a cup mouth diameter of 200mm, and a height of 200mm. 4) Bonding the crystal-leading section 9 and the crystal-leading rod: According to the process requirements, bond the crystal-leading section 9 to the front end of the blade body, and then bond the crystal-leading rod from the crystal-leading section 9 to the blade edge plate. Sharp corners that appear during the wax model welding process need to be rounded off, and the joints need to be trimmed and leveled to avoid misalignment of the wax parts. 5) Welding tree assembly system: The blades with the attached accessories are bonded between the base plate 1 and the wax pouring cup 3, and the blades are positioned using a limiting fixture. After welding, the blades are allowed to cool naturally for more than 8 hours. A gating channel 10 is connected between the pouring cup 3 and the spiral crystal selector 4, and a filter 11 is provided on the gating channel 10. 6) Cleaning and inspecting wax trees: After the wax trees are assembled, clean them three times. The first time, use the prepared cleaning solution to degrease them. The second and third times, use tap water to clean them. Specifically, when the robotic arm lifts and rotates the wax trees, it should be done at a uniform and slow speed. After the wax trees are immersed in the cleaning solution, fill them with low-pressure gas boiling solution to ensure that the oil stains on the surface of the wax trees are thoroughly cleaned.

[0020] Specifically, in step 5), the limiting fixture is integrally molded from foam. The limiting fixture includes a limiting plate 5, which has a slot 6 for positioning the blades. A semi-cylinder 7 is located at the lower end of the limiting plate 5. A limiting groove, which is semi-circular and coaxial with the central column 2, is located on the axial side of the semi-cylinder 7 and the limiting plate 5. A support column 8 is located on the edge of the limiting plate 5. The limiting plate 5 is semi-circular, and the semi-cylinder 7 is coaxial with the limiting plate 5. The slot 6 is located at the edge of the limiting plate 5 passing through the center, forming a lateral opening. After the tree assembly system is prepared, the limiting groove of the limiting fixture is fitted and fixed to the central column 2, and the supporting column 8 is used to balance and support the limiting plate 5, thereby determining the position of the slot 6. The slot 6 is used to position the blades. Specifically, the slot 6 on the limiting plate 5 is located at the blade edge plate position, and the inner wall contour of the slot 6 is consistent with the blade edge plate contour, ensuring the accuracy of blade installation. Example

[0021] The single-crystal large-size blade wax mold tree position control process in Example 1 was used to prepare the shell of large-size hollow single-crystal blade for heavy-duty gas turbines. This effectively optimized the process system for the large-scale tree production of heavy-duty gas turbine blades, enabling the shell to reach the international advanced level in terms of comprehensive performance, geometric dimensions and overall quality, and successfully realizing mass production and application.

[0022] The working principle of this invention is as follows: By employing a tree-assembly system with sufficient rigidity and strength, and using blade-limiting tooling to accurately determine the blade position, this invention solves the problems of displacement and insufficient positioning accuracy during blade tree assembly, thus improving the accuracy of the tree-assembly position. By ensuring the height consistency of the tree assembly, it solves the problem of tree position variation caused by uneven force during shell fabrication, thus improving the uniformity of force and the stability of the tree assembly during shell fabrication. By ensuring a uniform temperature gradient in the casting, it solves the problems of instability in the mushy region, casting deformation, or cracking caused by inconsistent temperature fields, thus improving the stability of casting quality. By overcoming the limitations of manual operation to achieve precise and stable control of the tree assembly position, this invention solves the inherent defects of existing large-size single-crystal tree assembly technology, thus improving the manufacturing quality and production efficiency of high-end blades.

[0023] The heavy-duty gas turbine blade shells prepared by this wax mold assembly and control process have significantly improved the relative accuracy of blade position. The blades achieve precise uniformity in angle consistency, perpendicularity, and distribution on the water-cooling plate. This results in a symmetrical shell structure and a more uniform temperature field distribution during casting. This not only greatly improves the product qualification rate but also significantly reduces manufacturing costs. At the same time, this process effectively optimizes the process system for the large-scale assembly and manufacturing of heavy-duty gas turbine blades, enabling the shells to reach international advanced levels in terms of comprehensive performance, geometric dimensions, and overall quality, and successfully achieving mass production and application.

[0024] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0025] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A single crystal large size blade wax pattern group tree position control process, characterized in that, It comprises the following steps: (1) pre-assembled spiral selector: according to the single crystal blade grain orientation requirements, select the appropriate spiral selector, and according to the reserved spiral selector using wax seed or alloy seed welding; (2) prepare the wax mold welding environment: the wax mold welding chamber temperature is 20-25℃, the humidity is 40-60%, and the adhesive wax is configured, the temperature is 130-150℃; (3) set the tree system: the tree system is divided into three parts, from bottom to top, the wax bottom plate, the wax coated hard alloy middle column and the wax pouring cup; (4) bonding of the crystal growth section and the crystal growth rod: according to the process requirements, the crystal growth section is bonded at the front end of the blade body, and then the crystal growth rod is bonded from the crystal growth section to the blade rim plate position; (5) welding the tree system: the blade with attached accessories is bonded between the bottom plate and the wax pouring cup, and the blade is positioned using a limiting tool, and after welding, it is naturally cooled for more than 8h; (6) cleaning and inspecting the wax tree: after the tree is set, the wax tree is cleaned three times, the first time using the prepared cleaning solution to degrease, the second and third times using tap water to clean.

2. A process for controlling the position of a large size single crystal blade wax pattern group tree as claimed in claim 1, wherein, In step 1), the height of the spiral selector is 45mm, the angle of the spiral selector is 45°, the diameter is 5mm, and the diameter of the seed crystal is 10mm and the height is 30mm.

3. A process for controlling the position of a large size single crystal wax pattern group tree according to claim 1, characterized in that, In step 3), the alloy rod and the metal disc are fixedly connected at the center to form a metal assembly, the metal assembly is placed in the wax mold to integrally pour the wax liquid, the outer sides of the metal disc and the alloy rod are wrapped with wax layers, and after demolding, an integrated structure of the wax bottom plate, the wax coated hard alloy middle column and the wax pouring cup is formed.

4. A process for controlling the position of a large size single crystal wax pattern group tree according to claim 1, characterized in that, In step 5), the limiting tool is integrally formed by foam, and the limiting tool comprises a limiting plate, the limiting plate is provided with a clamping groove for limiting the blade, the lower end of the limiting plate is provided with a semicircular column, the semicircular column and the limiting plate are coaxially provided with a limiting groove which is in contact with the middle column, and the edge of the limiting plate is provided with a supporting column.

5. A process for controlling the position of a large size single crystal wax blade mold set as claimed in claim 4, wherein, The limiting plate is semicircular, and the semicircular column is coaxially arranged with the limiting plate, the clamping groove is arranged at the edge of the limiting plate passing through the center, forming a lateral opening slot.

6. A process for controlling the position of a large size single crystal blade wax pattern group tree as claimed in claim 5, wherein, The clamping groove on the limiting plate is arranged at the blade rim plate position, and the inner wall contour of the clamping groove is consistent with the contour of the blade rim plate.

7. The single crystal large size blade wax mold tree position control process of claim 1, wherein a sprue is connected between the pouring cup and the spiral selector in step 5), and a filter is arranged on the sprue.

8. Use of a process for the control of the position of a group of wax models of large size blades of single crystals according to any one of claims 1 to 7, characterized in that, It is used for preparing a heavy gas large size hollow single crystal blade shell.

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