A connection structure between a single-crystal high-temperature alloy crystal selector and a casting.

Abstract

This utility model discloses a connection structure between a crystal selector and a casting of a single-crystal high-temperature alloy, including a ceramic mold shell. The crystal selector of the ceramic mold shell and the casting cavity are connected through an intermediate gating system. The key feature is that a ceramic ring is fixedly installed in the intermediate gating system. The ceramic ring has a central through-hole, and a chamfer is provided on the outer side of its lower end, extending to the position of the central through-hole. This utility model can provide a certain degree of deformation during the solidification and cooling stage of the single-crystal high-temperature alloy. This deformation can alleviate stress concentration at the protruding parts of the single-crystal turbine blade, thereby effectively reducing the risk of recrystallization.

Description

Technical Field

[0001] This utility model belongs to the field of high-temperature alloy preparation technology, and in particular relates to a connection structure between a single-crystal high-temperature alloy crystal selector and a casting. Background Technology

[0002] Directional solidification technology is widely used in the preparation of single-crystal superalloys, and high-speed solidification based on directional solidification is a conventional method for preparing single-crystal metals. Its basic principle is to induce epitaxial growth of the metal using temperature differences between different temperature zones. Single-crystal superalloys require the entire casting to maintain a consistent crystallographic orientation, which is usually achieved through a spiral crystal selector or seed crystal method. However, due to the difference in thermal expansion coefficients between the superalloy and the casting mold shell, the shrinkage of the superalloy during the cooling stage is much greater than that of the mold shell, while the size change of the mold shell is relatively small. This results in the casting being subjected to significant vertical tensile stress after cooling. Uneven shrinkage will cause a certain degree of sliding between the casting and the mold shell in the vertical direction; however, the complex structure of the single-crystal turbine blade rim plate, spiral crystal selector, and other structures restricts the shrinkage of the casting. This leads to stress concentration at the rim plate transition, resulting in plastic deformation. Simultaneously, with the increase in the content of refractory elements such as Re and Ru in high-generation new superalloys, the solution heat treatment temperature of single-crystal turbine blades is correspondingly increased, and the holding time is prolonged, which further exacerbates the risk of recrystallization defects. Summary of the Invention

[0003] The main purpose of this invention is to provide a connection structure between a single-crystal high-temperature alloy crystal selector and a casting, which is designed to provide a certain deformation during the solidification and cooling stage of the single-crystal high-temperature alloy. This deformation can alleviate the stress concentration at the protruding part of the single-crystal turbine blade, thereby effectively reducing the risk of recrystallization.

[0004] Therefore, this utility model provides a connection structure between a single-crystal high-temperature alloy crystal selector and a casting, including a ceramic mold shell. The crystal selector of the ceramic mold shell and the casting cavity are connected through an intermediate gating system. A ceramic ring is fixedly installed in the intermediate gating system. The ceramic ring has a central through hole. The lower outer side of the ceramic ring has a chamfer, which extends to the position of the central through hole.

[0005] Specifically, the ceramic ring and the ceramic mold shell are made of the same material.

[0006] Specifically, the diameter of the central through hole is 1 mm to 3 mm.

[0007] Compared with the prior art, the present invention has the following beneficial effects: The crystal selector and the casting cavity are connected through an intermediate gating system. A ceramic ring is installed in the intermediate gating system, and a central through hole is provided on the ceramic ring. The molten casting enters below through this small hole. The small cross-section of this area can generate a large yielding plastic deformation due to vertical tensile stress when the casting cools and shrinks, reducing the deformation generated at the casting edge plate that is in opposition to it. Moreover, this area of ​​the intermediate gating system will be removed in the final processing stage, which can effectively protect the single crystal consistency of the casting.

[0008] The bottom of the ceramic ring is chamfered to form a solute convection zone between the middle runner and the outer wall of the ceramic ring. By setting the solute convection zone, the low-density solute convection generated by dendrite segregation during the directional solidification process below will rise from the solute convection zones at the center and sides of the ceramic ring when it reaches the bottom of the ceramic ring. This design can suppress solute aggregation and thus reduce the formation of impurities and freckle defects. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is a schematic diagram of the intermediate gating system according to an embodiment of the present utility model; Among them: 1. intermediate runner; 2. ceramic ring; 3. central through hole; 4. chamfer; 5. solute convection zone; 6. upper end; 7. lower end. Detailed Implementation

[0011] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0012] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0013] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0014] See Figure 1 A single-crystal high-temperature alloy crystal selector and casting connection structure includes a ceramic mold shell (not shown in the figure). The crystal selector of the ceramic mold shell and the casting cavity are connected through an intermediate gating 1. A ceramic ring 2 is fixedly installed in the intermediate gating 1. The ceramic ring 2 is provided with a central through hole 3. The lower outer side of the ceramic ring 2 is provided with a chamfer 4, which extends to the bottom of the central through hole 3.

[0015] In this embodiment, the upper end 6 of the intermediate gating 1 is connected to the casting cavity, and the lower end 7 is connected to the crystal selector. A ceramic ring 2 is provided inside the intermediate gating 1, and a central through hole 3 is provided on the ceramic ring 2. The molten casting enters below through this small hole. The small cross-section of this area can generate a large yielding plastic deformation due to vertical tensile stress when the casting cools and shrinks, reducing the deformation generated at the casting edge plate that is opposed to it. Moreover, this area of ​​the intermediate gating 1 will be removed in the final processing stage, which can effectively protect the single crystal consistency of the casting. In addition, the bottom of the ceramic ring 2 is beveled, thereby forming a solute convection zone 5 between the intermediate gating 1 and the outer wall of the ceramic ring 2. By setting the solute convection zone, the low-density solute convection generated by dendrite segregation during the directional solidification process below will rise from the solute convection zone 5 at the center and both sides of the ceramic ring 2 when it reaches the bottom of the ceramic ring 2. This design can effectively suppress solute aggregation, thereby reducing the formation of impurities and freckle defects.

[0016] Understandably, the material of ceramic ring 2 depends on the mold shell material used in the casting system and must be consistent with it, including various components such as zirconium oxide and alumina. The purpose is to maintain the same amount of deformation during both hot and cold deformation. This ceramic ring 2 is a refractory material and will not introduce harmful impurities into the casting. The crystal selector can be a spiral crystal selector, or other similar crystal selectors.

[0017] See Figure 1 The ceramic ring 2 has a deformation zone at its center, with an inner diameter typically set between 1 mm and 3 mm. This hole should not be too small to allow the molten casting to pass through the central through-hole 3 and enter the lower part. The specific size depends on the size of the upper casting; when the upper casting is smaller, the inner diameter should be set even smaller. Furthermore, after solidification, the small cross-section of this area can undergo significant plastic deformation due to vertical tensile stress during the casting's cooling and shrinkage. The yielding deformation of the deformation zone reduces deformation at the opposing casting edge plate. Recrystallization defects may also occur in the casting area adjacent to the deformation zone during heat treatment, but this area is usually removed during the final machining stage. This effectively protects the single-crystal consistency of the casting.

[0018] Unless otherwise stated, if any of the technical solutions disclosed in this utility model discloses a numerical range, then the disclosed numerical range is a preferred numerical range. Anyone skilled in the art should understand that the preferred numerical range is merely one among many feasible numerical values ​​that has a more obvious or representative technical effect. Because there are many numerical values, it is impossible to list them all. Therefore, this utility model discloses only some numerical values ​​to illustrate the technical solutions of the invention. Furthermore, the numerical values ​​listed above should not constitute a limitation on the scope of protection of this invention.

[0019] Meanwhile, if the present invention discloses or relates to mutually fixedly connected parts or structural components, then unless otherwise stated, the fixed connection can be understood as: a detachable fixed connection (e.g., using bolts or screws), or a non-detachable fixed connection (e.g., riveting, welding). Of course, mutually fixed connections can also be replaced by an integral structure (e.g., manufactured by casting) (except where it is obviously impossible to use an integral forming process).

[0020] Furthermore, unless otherwise stated, the terms used to indicate positional relationships or shapes in any of the technical solutions disclosed in this utility model include states or shapes that are similar to, analogous to, or close to those states or shapes. Any component provided by this utility model can be assembled from multiple individual components or can be a single component manufactured using a one-piece molding process.

[0021] The above embodiments are merely illustrative examples to clearly illustrate the present invention, and are not intended to limit the implementation. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all embodiments here. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. A single crystal superalloy selector and casting connecting structure, comprising a ceramic mold shell, the selector and casting cavity of the ceramic mold shell are communicated through an intermediate sprue (1), characterized in that: The intermediate runner (1) is fixedly installed with a ceramic ring (2), the ceramic ring (2) is provided with a center through hole (3), the lower end outer side of the ceramic ring (2) is provided with an inverted bevel (4), and the inverted bevel (4) extends to the position of the center through hole (3).

2. The single crystal superalloy selector bar to casting joint of claim 1, wherein: The ceramic ring (2) is of the same material as the ceramic mold shell.

3. The single crystal superalloy selector bar to casting joint of claim 1, wherein: The diameter of the center through hole (3) is 1 mm-3 mm.

4. The single crystal superalloy selector bar to casting joint of claim 1, wherein: The crystal selector is a spiral crystal selector.

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