A method and mold for controlling columnar crystals in aero-engine turbine blade disks

Abstract

This invention discloses a method and mold for controlling columnar crystals in aero-engine turbine bladed disks, comprising: providing a turbine bladed disk wax model, the turbine bladed disk having a disk-shaped structure and blade structures surrounding the disk-shaped structure; performing a shell-making process on the turbine bladed disk wax model; arranging a plurality of flexible graphite chills, such that the middle part of each flexible graphite chill is located in an arc-shaped gap, the side of each flexible graphite chill abuts against the sidewall of the disk-shaped structure of a first intermediate mold shell, and both ends of each flexible graphite chill protrude from the blade structure of the first intermediate mold shell; performing a shell-making process on a second intermediate mold shell; and removing the shell-making material covering the two ends of the flexible graphite chills covering the second intermediate mold shell. This invention provides a method for controlling columnar crystals in aero-engine power turbine bladed disks, which can effectively reduce the size of columnar crystals in the hub and blade transition area of ​​the power turbine bladed disk or even eliminate columnar crystals.

Description

Technical Field

[0001] This invention relates to the field of aero-engine turbine bladed disk manufacturing technology, and more specifically to the field of precision casting of aero-engine turbine bladed disks, and particularly to a method for controlling columnar crystals in aero-engine turbine bladed disks. Background Technology

[0002] Turbine bladed disks are key components in aero engines and are typically mass-produced using precision casting (lost-wax casting). The principle involves creating a wax model using injection molding, casting a ceramic mold shell on the surface of the wax model, melting the wax model to obtain a mold shell with an embedded ceramic core, melting molten metal and pouring it into the ceramic mold shell, and after the molten metal cools, breaking and removing the ceramic mold shell to obtain the turbine bladed disk casting. The finished turbine bladed disk is then manufactured using machining and other methods.

[0003] The structure of an aircraft engine turbine disk consists of a hub and blades, such as... Figure 1 As shown, its structural features include a thick hub in the middle and thin-walled blades around it. Due to the structural characteristics of the power turbine bladed disk, one of the challenges in its precision casting technology is controlling the columnar crystal structure in the transition area between the blades and the hub, such as... Figure 2 As shown, the columnar crystals in this area are due to the thin blades, which dissipate heat quickly and solidify first, while the thick hub cools slowly. This results in a solidification sequence from the blades to the hub, causing the grains that nucleate first on the blades to grow radially towards the hub, forming columnar crystals. Normally, it is required that this area be free of columnar crystals or have columnar crystals smaller than a specified size. In actual production, substandard columnar crystals in this area can easily lead to the scrapping of castings. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a method for controlling columnar crystals in aero-engine turbine blade disks.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for controlling columnar crystals in aero-engine turbine blade disks, comprising:

[0007] S1. Provide a turbine bladed disk wax model, wherein the turbine bladed disk has a disk-shaped structure and a blade structure surrounding the disk-shaped structure;

[0008] S2. Perform a shell-making process on the outside of the turbine blade disk wax mold to obtain the first intermediate mold shell;

[0009] S3. Arrange several flexible graphite chills such that the middle part of each flexible graphite chill is located in the arc-shaped gap between two adjacent blade structures of the first intermediate mold shell, the side of each flexible graphite chill abuts against the side wall of the disc-shaped structure of the first intermediate mold shell, and the two ends of each flexible graphite chill protrude from the blade structure of the first intermediate mold shell to obtain a second intermediate mold shell.

[0010] S4. Perform a shell-making process on the second intermediate mold shell;

[0011] S5. Remove the shell-making material from both ends of the flexible graphite chill covering the second intermediate mold shell;

[0012] S6. Repeat steps S4 to S5 several times to obtain the finished mold shell.

[0013] The aforementioned method for controlling columnar crystals in aero-engine turbine blade disks further includes:

[0014] S7. Remove the wax mold from the finished mold shell to obtain the mold shell, and use the mold shell to carry out the casting process;

[0015] S8. Remove the mold shell after casting and cool it at room temperature.

[0016] The above-mentioned method for controlling columnar crystals in aero-engine turbine disks, wherein in step S2, the shell-making process includes applying a slurry and sandblasting to the surface of the turbine disk wax mold, so that the shell-making material covers the surface of the turbine disk wax mold.

[0017] In the above-mentioned method for controlling columnar crystals in aero-engine turbine blade disks, in step S3, the flexible graphite chill has a first surface, a second surface, and the side surface, such that at least a portion of the middle part of the first surface and / or the second surface of the flexible graphite chill is in contact with the blade structure of the first intermediate mold shell.

[0018] In the above-mentioned method for controlling columnar crystals in aero-engine turbine blade disks, in step S4, the shell-making process includes applying slurry and sandblasting to the surface of the second intermediate mold shell, so that the shell-making material covers the surface of the second intermediate mold shell, and the shell-making material covers the surface of the flexible graphite chill.

[0019] In the above-mentioned method for controlling columnar crystals in aero-engine turbine blade disks, in steps S5 and S6, the middle part of the flexible graphite chill is embedded in the finished mold shell, while ensuring that both ends of the flexible graphite chill are exposed.

[0020] In the aforementioned method for controlling columnar crystals in aero-engine turbine blade disks, steps S5 and S6 ensure that the exposed portions at both ends of the flexible graphite chill do not break.

[0021] In the above-mentioned method for controlling columnar crystals in aero-engine turbine blade disks, in steps S5 and S6, it is ensured that both ends of the flexible graphite chill protrude 5-10 mm beyond the finished mold shell.

[0022] In the aforementioned method for controlling columnar crystals in aero-engine turbine blade disks, the thickness of the flexible graphite chill is 1-2 mm less than the arc-shaped gap.

[0023] In the aforementioned method for controlling columnar crystals in aero-engine turbine blade disks, the width of the flexible graphite chill is equal to the thickness of the flexible graphite chill, or extends to the middle of the radial direction of the blade structure.

[0024] A turbine bladed disk mold for an aircraft engine, comprising:

[0025] A first structure and a plurality of second structures arranged around the first structure, the first structure and the second structures being connected, wherein the first structure has a disc-shaped cavity that matches the disc-shaped structure of the turbine blade disk wax model, the second structure has a blade cavity that matches the blade structure of the turbine blade disk wax model, and the blade cavity and the disc-shaped cavity are connected.

[0026] A flexible graphite chill is embedded between two adjacent second structures, and the middle part of the flexible graphite chill is covered by part of the material of the two adjacent second structures.

[0027] In the aforementioned aircraft engine turbine bladed disk mold, both the first structure and the second structure are provided by shell-making material;

[0028] The two ends of the flexible graphite chill protrude from the second structure;

[0029] The flexible graphite chill has a first surface, a second surface, and a side surface, wherein a layer of the shell-forming material is provided between the side surface of the flexible graphite chill and the disc-shaped cavity, and a layer of the shell-forming material is also provided between the first surface of the flexible graphite chill and the blade cavity, and / or between the second surface of the flexible graphite chill and the blade cavity.

[0030] The present invention, by employing the above-mentioned technology, has the following positive effects compared with the prior art:

[0031] (1) This invention provides a method for controlling columnar crystals in aero-engine power turbine disks, which can effectively reduce the size of columnar crystals in the hub and blade transition area of ​​the power turbine disk and even eliminate columnar crystals. It has a significant effect on improving the precision casting yield of power turbine disks. This method is low in cost and easy to operate.

[0032] (2) The present invention sets a flexible graphite chill with thermal conductivity far superior to that of the mold shell in the area where the blade and hub are connected (the area where columnar crystals appear), thereby accelerating the cooling rate of the area and preventing the grains in the blade area from growing laterally into columnar crystals in the direction of the hub. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the aero-engine power turbine disk of the columnar crystal control method of the aero-engine turbine disk of the present invention.

[0034] Figure 2 This is a schematic diagram of the external structure of the turbine disk of an aero-engine, which is the control method for columnar crystals in aero-engine turbine disks according to the present invention.

[0035] Figure 3 This is a schematic diagram of the columnar crystal control method for aero-engine turbine blade disks according to the present invention.

[0036] Figure 4 This is a schematic diagram of the columnar crystal control method for aero-engine turbine blade disks according to the present invention.

[0037] In the attached diagram: A, columnar crystal; 1, turbine blade disk wax model; 11, disk structure; 12, blade structure; 2, first intermediate mold shell; 21, disk structure; 22, blade structure; 3, flexible graphite chill. Detailed Implementation

[0038] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0039] Unless otherwise defined, the technical or scientific terms used in the claims and description shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0040] The word "comprising" or similar terms used in the specification and claims of this patent application mean that the objects preceding "comprising" include the objects listed after "comprising" or their equivalents, and do not exclude other objects.

[0041] In the description of this invention, it should be understood that the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "inner", "outer", "front", "rear", "lateral", and "vertical" are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, and therefore should not be construed as a limitation of this invention.

[0042] It should be noted that the terms "horizontal" and "vertical" in this invention are used to describe approximate positional relationships, and not strictly "horizontal plane" or "vertical plane".

[0043] Please see Figures 1 to 4 The diagram illustrates a preferred embodiment of a columnar crystal control method for an aero-engine turbine blade disk, comprising:

[0044] S1. Provide a turbine bladed disk wax model 1, the turbine bladed disk having a disk-shaped structure 11 and a blade structure 12 surrounding the disk-shaped structure 11.

[0045] S2. Perform a shell-making process on the outside of the turbine blade disk wax mold 1 to obtain the first intermediate mold shell 2;

[0046] S3. Arrange several flexible graphite chills 3 such that the middle part of each flexible graphite chill 3 is located in the arc-shaped gap between two adjacent blade structures 22 of the first intermediate mold shell 2, the side of each flexible graphite chill 3 abuts against the side wall of the disc-shaped structure 21 of the first intermediate mold shell 2, and the two ends of each flexible graphite chill 3 protrude from the blade structure 22 of the first intermediate mold shell 2 to obtain the second intermediate mold shell.

[0047] S4. Perform shell-making process on the second intermediate mold shell;

[0048] S5. Remove the shell-making material from both ends of the flexible graphite chill covering the second intermediate mold shell.

[0049] S6. Repeat steps S4 to S5 several times to obtain the finished mold shell.

[0050] S7. Remove the wax mold from the finished mold shell to obtain the mold shell, and use the mold shell to carry out the casting process;

[0051] S8. Remove the cast mold shell and allow it to cool at room temperature.

[0052] In this embodiment, the cooling of the area where the blade and the hub are connected is accelerated by arranging flexible graphite chills 3, which prevents columnar crystals from growing in this area. Since the two ends of the flexible graphite chills 3 protrude from the mold shell and are exposed, they are in contact with the room temperature environment and have good thermal conductivity, which can accelerate the cooling rate of the outer edge of the hub, that is, the part that is connected to the blade.

[0053] On the other hand, since the surface of the flexible graphite chill 3 is also close to the blade arrangement, it can make the temperature of the blade and hub transition area uniform, so that the blade root and the outer edge of the hub have similar cooling temperatures.

[0054] Furthermore, as a preferred embodiment, in S1, the disc-shaped structure is a hub structure.

[0055] Furthermore, as a preferred embodiment, in S2, the shell-making process includes applying a slurry and applying sand to the surface of the turbine bladed disk wax mold, so that the shell-making material covers the surface of the turbine bladed disk wax mold 1.

[0056] Furthermore, as a preferred embodiment, in S3, the flexible graphite chill 3 has a first surface, a second surface, and a side surface, such that at least a portion of the middle part of the first surface and / or the second surface of the flexible graphite chill 3 is in contact with the blade structure 22 of the first intermediate mold shell 2.

[0057] Among them, the first and second surfaces of the flexible graphite chill 3 are respectively Figure 4 The left side and the side surface of the flexible graphite chill 3 are... Figure 4 The lower side of the middle.

[0058] For example, the middle of the first surface of the flexible graphite chill 3 is completely attached to a blade structure 22 of the first intermediate mold shell 2.

[0059] For example, the middle of the second surface of the flexible graphite chill 3 is completely fitted with another blade structure 22 of the first intermediate mold shell 2.

[0060] For example, a portion of the middle of the first surface of the flexible graphite chill 3 is attached to one blade structure 22 of the first intermediate mold shell 2, while a portion of the middle of the second surface of the flexible graphite chill 3 is attached to another blade structure 22 of the first intermediate mold shell 2.

[0061] Furthermore, as a preferred embodiment, in S4, the shell-making process includes applying slurry and sandblasting to the surface of the second intermediate mold shell, so that the shell-making material covers the surface of the second intermediate mold shell, and the shell-making material covers the surface of the flexible graphite chill.

[0062] Furthermore, as a preferred embodiment, in S5 and S6, the middle part of the flexible graphite chill 3 is embedded in the finished mold shell, while ensuring that both ends of the flexible graphite chill 3 are exposed by 5-10mm.

[0063] Furthermore, as a preferred embodiment, in S5 and S6, it is ensured that the exposed portions at both ends of the flexible graphite chill 3 do not break.

[0064] Furthermore, as a preferred embodiment, in S5 and S6, the two ends of the flexible graphite chill 3 are ensured to protrude 5-10 mm beyond the finished mold shell.

[0065] That is, the flexible graphite chill 3 is covered by the mold shell except for the two end areas, and is embedded inside the mold shell.

[0066] Furthermore, as a preferred embodiment, the thickness of the flexible graphite chill 3 is less than 1-2 mm than the arc-shaped gap.

[0067] Furthermore, as a preferred embodiment, the width of the flexible graphite chill 3 is equal to the thickness of the flexible graphite chill 3, or extends to the center in the radial direction of the blade structure.

[0068] Preferably, the flexible graphite chill 3 can be made of columnar graphite strips. For cases where columnar crystals are severe or long, the flexible graphite chill 3 can be made of wider graphite sheets to increase the area of ​​influence of the graphite.

[0069] In this embodiment, the thickness of the flexible graphite chill 3 specifically refers to... Figure 4 The thickness in the left-right direction, and the width of the flexible graphite chill 3 specifically refer to... Figure 4 Width in the top and bottom directions.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the implementation and protection scope of the present invention.

[0071] In addition to the above, the present invention also has the following embodiments:

[0072] In a further embodiment of the present invention, an aero-engine turbine disk mold is also provided, comprising: a first structure and a plurality of second structures arranged around the first structure, the first structure and the second structure being connected, wherein the first structure has a disk-shaped cavity that matches the disk-shaped structure of the turbine disk wax mold, the second structure has a blade cavity that matches the blade structure of the turbine disk wax mold, and the blade cavity and the disk-shaped cavity are connected.

[0073] In a further embodiment of the present invention, the turbine disk mold for an aero-engine further includes: a flexible graphite chill, which is embedded between two adjacent second structures, and the middle part of the flexible graphite chill is covered by part of the material of the two adjacent second structures.

[0074] In a further embodiment of the present invention, both the first structure and the second structure are provided by shell-making material.

[0075] In a further embodiment of the present invention, the shell-making materials are slurry and sand.

[0076] In a further embodiment of the present invention, the two ends of the flexible graphite chill protrude from the second structure.

[0077] In a further embodiment of the present invention, the flexible graphite chill has a first surface, a second surface, and a side surface, wherein a shell material is provided between the side surface of the flexible graphite chill and the disc-shaped cavity, and a shell material is also provided between the first surface of the flexible graphite chill and the blade cavity, and / or between the second surface of the flexible graphite chill and the blade cavity.

[0078] The above description is merely a preferred embodiment of the present invention and does not limit the implementation and protection scope of the present invention. Those skilled in the art should realize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for controlling columnar crystals in aero-engine turbine blade disks, characterized in that, include: S1. Provide a turbine bladed disk wax model, wherein the turbine bladed disk has a disk-shaped structure and a blade structure surrounding the disk-shaped structure; S2. Perform a shell-making process on the outside of the turbine blade disk wax mold to obtain the first intermediate mold shell; S3. Arrange several flexible graphite chills such that the middle part of each flexible graphite chill is located in the arc-shaped gap between two adjacent blade structures of the first intermediate mold shell, the side of each flexible graphite chill abuts against the side wall of the disc-shaped structure of the first intermediate mold shell, and the two ends of each flexible graphite chill protrude from the blade structure of the first intermediate mold shell to obtain the second intermediate mold. S4. Perform shell-making process on the second intermediate mold; S5. Remove the shell material from both ends of the flexible graphite chill covering the second intermediate mold; S6. Repeat steps S4 to S5 several times to obtain the finished mold shell; In S3, the flexible graphite chill has a first surface, a second surface, and the side surface, such that at least a portion of the middle part of the first surface and / or the second surface of the flexible graphite chill is in contact with the blade structure of the first intermediate mold shell. In S5 and S6, the middle part of the flexible graphite chill is embedded in the finished mold shell, while ensuring that both ends of the flexible graphite chill are exposed. In steps S5 and S6, ensure that the exposed portions at both ends of the flexible graphite chill do not break. In steps S5 and S6, ensure that both ends of the flexible graphite chill protrude 5-10mm beyond the finished mold shell.

2. The method for controlling columnar crystals in aero-engine turbine blade disks according to claim 1, characterized in that, Also includes: S7. Remove the wax mold from the finished mold shell to obtain the mold shell, and use the mold shell to carry out the casting process; S8. Remove the mold shell after casting and cool it at room temperature.

3. The method for controlling columnar crystals in aero-engine turbine blade disks according to claim 1, characterized in that, In S2, the shell-making process includes applying a slurry and sandblasting to the surface of the turbine bladed disk wax mold, so that the shell-making material covers the surface of the turbine bladed disk wax mold.

4. The method for controlling columnar crystals in aero-engine turbine blade disks according to claim 1, characterized in that, In S4, the shell-making process includes applying a paste and applying sand to the surface of the second intermediate mold, so that the shell-making material covers the surface of the second intermediate mold, and the shell-making material covers the surface of the flexible graphite chill.

5. The method for controlling columnar crystals in aero-engine turbine blade disks according to claim 1, characterized in that, The thickness of the flexible graphite chill is 1-2 mm less than the arc-shaped gap.

6. The method for controlling columnar crystals in aero-engine turbine blade disks according to claim 1, characterized in that, The width of the flexible graphite chill is equal to the thickness of the flexible graphite chill, or extends to the middle of the radial direction of the blade structure.

7. A turbine bladed disk mold for an aero-engine, prepared using the columnar crystal control method for aero-engine turbine bladed disks as described in claim 1, characterized in that... include: A first structure and a plurality of second structures arranged around the first structure, the first structure and the second structures being connected, wherein the first structure has a disc-shaped cavity that matches the disc-shaped structure of the turbine blade disk wax model, the second structure has a blade cavity that matches the blade structure of the turbine blade disk wax model, and the blade cavity and the disc-shaped cavity are connected. A flexible graphite chill is embedded between two adjacent second structures, and the middle part of the flexible graphite chill is covered by part of the material of the two adjacent second structures.

8. The aircraft engine turbine bladed disk mold according to claim 7, characterized in that, Both the first structure and the second structure are provided by shell-making material; The two ends of the flexible graphite chill protrude from the second structure; The flexible graphite chill has a first surface, a second surface, and a side surface, wherein a layer of the shell-forming material is provided between the side surface of the flexible graphite chill and the disc-shaped cavity, and a layer of the shell-forming material is also provided between the first surface of the flexible graphite chill and the blade cavity, and / or between the second surface of the flexible graphite chill and the blade cavity.

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