CN111496182A

CN111496182A - Precision casting method for preventing deformation of single-crystal duplex block-cast turbine guide vane edge plate

Info

Publication number: CN111496182A
Application number: CN202010412376.9A
Authority: CN
Inventors: 张剑; 郭媛媛; 杨振宇; 刘晨光; 郑帅; 骆宇时
Original assignee: AECC Beijing Institute of Aeronautical Materials
Current assignee: AECC Beijing Institute of Aeronautical Materials
Priority date: 2020-05-15
Filing date: 2020-05-15
Publication date: 2020-08-07
Anticipated expiration: 2040-05-15
Also published as: CN111496182B

Abstract

The invention relates to a precision casting method for preventing a guide vane flange plate of a single-crystal duplex block-cast turbine from deforming, which comprises the following steps: pressing a single crystal duplex integral casting turbine guide vane wax mold to be cast, and reshaping an upper edge plate and a lower edge plate of the guide vane wax mold; sticking wax sheets on the edge plates of the wax mould of the single crystal duplex integral casting turbine guide vane after shape correction, wherein the sticking positions of the wax sheets are the edge part of the cantilever of the edge plate on one side of the back of the single crystal duplex integral casting turbine guide vane farthest from the air inlet edge of the blade and the other end of the edge plate on the same side, and the sizes of the wax sheets are designed according to the sizes of the corresponding upper edge plate and the lower edge plate; and preparing the single crystal duplex integral casting turbine guide vane by utilizing the guide vane wax mould which is shaped and provided with the wax sheet. According to the method, the deformation of the blade edge plate is corrected and compensated through correcting and sticking the wax sheet at the wax mould stage, so that the deformation of the single-crystal double-integrated-casting turbine guide vane edge plate is reduced, and the qualified rate of the size of the edge plate of the product is improved.

Description

Precision casting method for preventing deformation of single-crystal duplex block-cast turbine guide vane edge plate

Technical Field

The invention belongs to the technical field of blade precision casting, and particularly relates to a precision casting method for preventing a guide vane edge plate of a single-crystal duplex block-cast turbine from deforming.

Background

The turbine guide vane (guide vane) which is a core component of an aero-engine adopts a duplex integral casting process of investment precision casting, the single crystal duplex integral casting turbine guide vane is in duplex integral casting, the edge plate span length of the vane is 70mm, the whole span of the vane reaches 270mm, the vane has large three-dimensional size and height composite bending and twisting, and the circumferential angle reaches 40 degrees. The single crystal duplex block casting turbine guide vane has high reliability and greatly improved bearing capacity, but brings great challenges to blade casting, and the casting size is more difficult to control. Therefore, in order to ensure that the size of the blade meets the design requirements, the deformation control of the edge plate is required after the wax mold is pressed. The deformation control of the edge plate also becomes the key for the successful development of the blade.

In order to control the deformation of the flange plate, the traditional deformation control method is to weld a wax sheet with the length and width of 8 x 3mm after the wax mold is pressed to prevent the deformation of the flange plate, although the method can solve the partial deformation problem, the batch property is poor, the sizes of the wax mold and the flange plate of a casting are difficult to control consistently, and the sizes of the flange plate cannot be controlled consistently and accurately only by welding a wax rod and the wax sheet, in particular to a novel started single-crystal duplex block casting turbine guide vane.

Disclosure of Invention

In view of the above-mentioned circumstances of the prior art, it is an object of the present invention to provide a precision casting method for preventing deformation of a single crystal twin block turbine vane panel to control deformation of the single crystal twin block turbine vane panel during wax pattern pressing and cast cooling.

The above object of the present invention is achieved by the following technical solutions:

a precision casting method for preventing deformation of a guide vane flange plate of a single-crystal duplex block-cast turbine comprises the following steps:

pressing a single crystal duplex integral casting turbine guide vane wax mold to be cast, and reshaping an upper edge plate and a lower edge plate of the guide vane wax mold; the design size of the orthopedic tool is equal to the design size of the wax mould (1-wax mould shrinkage rate), the orthopedic time of the orthopedic tool is generally 3-10 minutes, and the size of the orthopedic wax mould edge plate is consistent with the design size of the orthopedic tool.

And sticking a wax sheet on the edge plate of the single crystal double-linkage integrally cast turbine guide vane wax mould after the shape is corrected. The wax sheet sticking position is the edge part of the cantilever of the edge plate on one side of the blade back of the single-crystal duplex block-cast turbine guide blade farthest from the air inlet edge of the blade and the other end of the edge plate on the same side; like this, through setting up the wax sheet, the accessible carries out reverse control to blade wax matrix state, and the deformation that the control blade takes place in the pouring process to the deformation of turbine blade flange department has been reduced. Wherein the length of wax chip is for corresponding hookup location department, and the theoretical distance between the lower flange plate of stator blade wax matrix subtracts corresponding blade flange deflection, corresponding deflection is: the actual distance between the upper and lower edge plates of the guide vane casting at the connecting position-the theoretical distance between the guide vane casting at the connecting position) ((1 +), wherein the shrinkage rate of the casting metal material in the wax sheet connecting direction is determined jointly according to the anisotropy of the metal material and the mold assembly angle (namely, the blade placement angle), and the actual distance between the upper and lower edge plates of the guide vane casting at the connecting position is obtained by measuring the blade casting prepared in the earlier stage.

And preparing the single-crystal double-linkage integral casting turbine guide vane by utilizing the guide vane wax mould which is shaped and provided with the wax sheet.

The method further comprises the step of cutting off the metal process ribs formed at the wax sheet position after the casting forming of the single-crystal duplex block-cast turbine guide vane is completed, and the cutting off is carried out in a linear cutting mode.

According to the precision casting method for preventing the deformation of the single-crystal duplex block-cast turbine guide vane edge plate, the wax mould shape-righting tool is adopted in the preparation process of the wax mould of the blade, so that the deformation of the wax mould state is favorably controlled, and the wax sheet is arranged, so that the deformation of the wax mould in the pouring process can be controlled, and the reverse control can be carried out on the wax sheet, therefore, the deformation of the turbine blade edge plate is reduced, and the dimensional qualification rate of the edge plate is greatly improved.

Drawings

FIG. 1 is a schematic diagram illustrating the use of an orthopedic tool to orthopedic a flange plate in the method of the present invention;

FIG. 2 is a schematic cross-sectional view of a wax sheet in the process of the present invention;

FIG. 3 is a schematic view of a blade after wax coating in the process of the present invention.

Detailed Description

For a clearer understanding of the objects, technical solutions and advantages of the present invention, the present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

The invention provides a method for preventing a guide vane flange plate of a single-crystal duplex block-cast turbine from deforming in order to control the deformation of the guide vane flange plate of the single-crystal duplex block-cast turbine in the processes of wax mold pressing, pouring and cooling.

Specifically, in this embodiment, first, according to a drawing of a blank of a twin-block turbine guide vane to be cast, a wax mold for pressing a single-crystal twin-block turbine guide vane to be cast is designed, and upper and lower edge plates of the wax mold for guide vane are reshaped, wherein the reshaping is achieved by reshaping the edge plates by respectively using edge plate reshaping tools on flow passage surfaces of the upper and lower edge plates, as illustrated in fig. 1. In fig. 1, the straightening flaps (i.e., the straightening tools) are illustrated as being provided on both sides of the right blade platform, and the straightening flaps (not shown) are also provided on both sides of the left blade platform. The method has the advantages that the method adopts the orthopedic tool to orthopedic the wax mould, which is the conventional skill of technicians in the field, and the orthopedic steps are not described in detail; wherein: the design size of the orthopedic tool of the wax mould is inconsistent with the design size of the wax mould, namely the design size of the orthopedic tool is equal to the design size of the wax mould (1-wax mould shrinkage rate). The orthopedic time is generally 3 to 10 minutes, in this case 5 minutes. The orthopedic process is carried out in the temperature range of 20 +/-2 ℃ for the wax mould storage.

Step 2: and sticking a wax sheet on the edge plate of the single crystal double-linkage integrally cast turbine guide vane wax mould after the shape is corrected. Wax sheets of two specifications are designed according to the sizes of the upper and lower edge plates, namely a first wax sheet 1 and a second wax sheet 2, so that the edge plates are prevented from deforming. Wherein the first wax sheet 1 is located at the position 3mm away from the edge part of the cantilever of the edge plate farthest from the air inlet edge of the blade on one side of the blade back (as schematically shown in fig. 3), the second wax sheet 2 is located at the position 3mm away from the edge part of the edge plate of the blade on the other end of the edge plate on the same side as the first wax sheet 1 (as schematically shown in fig. 3), and the wax mould stuck with the wax sheets is shown in fig. 3. In the present embodiment, the first wax sheet 1 and the second wax sheet 2 each have a cross-sectional dimension of 8mm by 3mm, see fig. 2. The length of wax sheet is for corresponding hookup location department, and the theoretical distance between the lower flange plate of stator blade wax matrix subtracts corresponding blade flange deformation, corresponding deformation is: the actual distance between the upper and lower edge plates of the guide vane casting at the connection position-the theoretical distance between the guide vane casting at the connection position) × (1+), wherein the shrinkage rate of the metal material of the casting in the wax sheet connection direction is determined by the anisotropy of the metal material and the mold assembly angle (i.e., the blade arrangement angle), which is a routine skill of those skilled in the art and will not be described in detail. The actual distance between the upper and lower edge plates of the guide vane casting at this connection position was obtained by measurement of the previously prepared vane casting, and the amount of deformation in this example was calculated to be 0.26 mm. Like this, through setting up the wax chip, the accessible carries out reverse control to the double block turbine stator of single crystal, the deformation that the control double block turbine stator of single crystal takes place in the pouring process to the deformation of blade flange department has been reduced.

Casting the single-crystal duplex integral-casting turbine guide vane by adopting the guide vane wax mold which is shaped and provided with the wax sheet; in this embodiment, the casting process of the turbine vane is the same as the casting process without the reshaping.

And finally, after the single-crystal duplex block-cast turbine guide vane blank is cast and formed, cutting off the process ribs formed at the positions where the wax molds are arranged along the side surfaces of the upper edge plate and the lower edge plate of the blade in a linear cutting mode.

The method of the invention effectively controls the deformation of the wax mould state by adopting the wax mould for reshaping, and greatly reduces the deformation of the blade edge plate by adopting the anti-deformation process ribs. Through a contrast test, five blades are not corrected, the sizes of 16 measuring points are all out of tolerance, the minimum out-of-tolerance amount is 0.18mm, the maximum out-of-tolerance amount is 0.46mm, after the deformation prevention process is adopted, three blades in the five blades are qualified, two blades are out of tolerance, but the out-of-tolerance amount is obviously reduced, and the maximum out-of-tolerance amount is 0.06 mm.

Claims

1. A precision casting method for preventing deformation of a guide vane flange plate of a single-crystal duplex block-cast turbine comprises the following steps:

pressing a single crystal duplex integral casting turbine guide vane wax mold to be cast, and reshaping an upper edge plate and a lower edge plate of the guide vane wax mold;

sticking wax sheets on the edge plates of the wax mould of the single crystal duplex integral casting turbine guide vane after shape correction, wherein the sticking positions of the wax sheets are the edge part of the cantilever of the edge plate on one side of the back of the single crystal duplex integral casting turbine guide vane farthest from the air inlet edge of the blade and the other end of the edge plate on the same side, and the sizes of the wax sheets are designed according to the sizes of the corresponding upper edge plate and the lower edge plate;

and preparing the single crystal duplex integral casting turbine guide vane by utilizing the guide vane wax mould which is shaped and provided with the wax sheet.

2. The method of claim 1, further comprising cutting off metal technology ribs formed at the location of the wax sheet after completing the cast forming of the single crystal twin block turbine vane.

3. The method of claim 2 wherein the metal process bead is cut by wire cutting.

4. The method according to claim 1, wherein the sizing of the orthopedic tool for orthopedic shaping of the upper and lower edge plates of the guide vane wax mold is the wax mold sizing (1-wax mold shrinkage).

5. A method according to claim 4, wherein the reshaping takes place over a period of 3 to 10 minutes at a temperature within which the wax model is stored.

6. The method of claim 1, wherein the length of the wax sheet is the theoretical distance between the upper and lower flanges of the vane wax pattern at the corresponding connection location minus the corresponding blade flange deflection.

7. The method of claim 6, wherein the corresponding deformation amounts are: the actual spacing of the upper and lower flanges of the vane casting at this junction-the theoretical spacing of the vane casting at this location-is 1+, which is the shrinkage of the casting metal material in the direction of wax sheet junction.

8. The method according to claim 1, wherein the wax sheet has a cross-sectional dimension of 8mm by 3 mm.