A method for removing a ceramic core of a composite core blade of an aeroengine

Abstract

The present application relates to a kind of ceramic core removal methods of aero-engine composite core blade, comprising the following steps: S1, the ceramic core removal of aero-engine composite core blade is carried out;S2, the aero-engine composite core blade treated after S1 is neutralized and cleaned;S3, the further ceramic core removal of aero-engine composite core blade is carried out;S4, the aero-engine composite core blade treated after S3 is cleaned and dried.The method can ensure that composite core is completely removed, no residual core, while ensuring the removal efficiency of composite core and reducing the corrosion to blade, effectively solve the problem of aluminum-based core and composite core, to meet the requirements of aero-engine development to blade core material.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ceramic core removal of core blades, and relates to a ceramic core removal method for a composite core blade of an aero-engine. BACKGROUND

[0002] With the improvement of the performance of the aero-engine, the thrust-to-weight ratio, the turbine inlet gas temperature and the compressor pressure ratio are continuously improved, and the temperature resistance of the hollow blade for the aero-engine also needs to be further improved. The development of single crystal and eutectic blades greatly improves the service life and service temperature of the blades, but also increases the casting temperature of the blades. The silicon-based core with weak core strength cannot meet the casting conditions of the advanced single crystal and eutectic blades. The aluminum-based core has high chemical stability and good creep resistance, which makes up for the shortcomings of the silicon-based ceramic core. The aluminum-based ceramic core takes Al2O3 as the main raw material, and the reaction rate of Al2O3 with fluoride melt or hydrofluoric acid solution is extremely slow at low temperature and low pressure. Al2O3 after secondary sintering hardly reacts with potassium hydroxide due to low porosity. The traditional removal method of the aluminum-based ceramic core is to use fluoride melt or hydrofluoric acid solution for core removal. Such method has low core removal efficiency, and long-time core removal will further aggravate the corrosion of the blade and cause great harm to the human body and the environment.

[0003] Single ceramic material cannot meet the requirements of core preparation process and use performance, and cannot meet the requirements of high-temperature structural stability, chemical compatibility and dissolution at the same time. The composite core has become a trend of development of the blade of the aero-engine. At present, the silicon-based and aluminum-based composite core is the most commonly used composite core. The current blade core removal method of the composite core is to use low-concentration potassium hydroxide solution for core removal at low temperature and low pressure, and the core removal time is as long as hundreds of hours, the qualified rate is low, the blade is greatly corroded and damaged, and the method cannot meet the needs of industrial production. SUMMARY

[0004] The purpose of the application is to overcome the shortcomings of the prior art, and to provide a ceramic core removal method for a composite core blade of an aero-engine, which can ensure complete removal of the composite core without residual core, can ensure the removal efficiency of the composite core and reduce the corrosion of the blade, effectively solves the core removal problem of the aluminum-based core and the composite core, and meets the requirements of the development of the aero-engine for the core material of the blade.

[0005] In order to achieve the above purpose, the application adopts the following technical scheme:

[0006] A ceramic core removal method for a composite core blade of an aero-engine, characterized in that it comprises the following steps:

[0007] S1, removing the ceramic core of the composite core blade of the aero-engine;

[0008] S2, neutralizing and cleaning the aero-engine composite core blade treated in S1;

[0009] S3, further removing the ceramic core of the aero-engine composite core blade;

[0010] S4, cleaning and drying the aero-engine composite core blade treated in S3.

[0011] Further, the S1 specifically comprises the following steps:

[0012] S11, placing the blade in the kettle body of the reaction kettle containing 30%-40% potassium hydroxide solution, turning on the heating disc to 150-170°C, opening the stop valve, and spraying 0.1-0.7 MPa high-pressure inert gas through the one-way valve nozzle of the gas pipeline, opening the exhaust valve to discharge the high-pressure gas after 6 minutes, and repeating the cycle for 12 hours.

[0013] S12, turning the blade position by 180° and performing the same treatment as S11.

[0014] Further, the placing of the blade in the reaction kettle in S11 is specifically as follows: placing the blade in the hopper after spirally arranging it, buckling the hopper cover, then immersing the hopper in the kettle body, placing the sealing ring and buckling the upper plug of the kettle body.

[0015] Further, S12 is specifically as follows: removing the sealing ring and the upper plug, taking out the hopper, turning the blade by 180° and placing it in the hopper again, and buckling the hopper cover.

[0016] Further, S2 is specifically as follows: removing the sealing ring and the upper plug, taking out the hopper, placing the blade in the citric acid with air stirring for 30 minutes, and then placing it in the clean water with air stirring for 10 minutes.

[0017] Further, S3 is specifically as follows: placing the blade obtained in S2 in the hopper again, buckling the hopper cover, immersing the hopper and the hopper cover in the kettle body containing 40%-60% potassium hydroxide solution, placing the sealing ring and buckling the upper plug, turning on the heating disc to 400-500°C, opening the stop valve, and spraying 20-30 MPa high-pressure inert gas through the gas pipeline and the one-way valve nozzle, opening the exhaust valve to discharge the high-pressure gas after 6 minutes, and repeating the cycle for 2 hours.

[0018] Further, S4 is specifically as follows: using high-pressure water to flush the inner cavity channel of the blade obtained in S3 for 5 minutes, and then placing the blade in the drying box at a temperature of 120°C for drying for 30 minutes.

[0019] Further, when the blade is spirally arranged, the tenon is downward.

[0020] Further, the S11 is used for removing silicon-based ceramic cores in the tenon and the tip of the composite core blade and softening the silicon-based ceramic cores in the blade body composite core; the S12 is used for removing the silicon-based ceramic cores in the blade body composite core and softening the aluminum-based ceramic cores in the tenon and the tip; and the S3 is supercritical removal, which is used for removing the remaining aluminum-based ceramic cores of the composite core blade.

[0021] Compared with the prior art, the method has the following beneficial effects:

[0022] The application provides a ceramic core removal method for a composite core blade of an aero-engine, which comprises pre-removal and secondary supercritical fluid removal, wherein the pre-removal can remove most of the cores and soften the residual cores, and the secondary supercritical fluid core removal process makes a potassium hydroxide solution as a core removal medium in a supercritical fluid state; the potassium hydroxide solution in the supercritical fluid state has extremely low surface tension and can quickly and completely wet the contact surface of the softened ceramic cores, so that the core removal reaction rate is accelerated; the application can guarantee the core removal efficiency and effect and has no corrosion on the blade, and provides a new direction for the ceramic core removal of the composite core blade.

[0023] Other features and advantages of the application will become apparent from the following detailed description of exemplary embodiments thereof, with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0024] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description, serve to explain the principles of the application.

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, for those skilled in the field, other drawings can also be obtained from these drawings without any creative work.

[0026] Figure 1 The structure diagram of the reaction kettle used in the ceramic core removal method of the application;

[0027] Figure 2 The metallographic diagram of the blade after the composite core removal of the application.

[0028] 1, kettle body; 2, upper plug; 3, sealing ring; 4, barrel cover; 5, barrel; 6, one-way valve nozzle; 7, gas pipeline; 8, stop valve; 9, heating disc; 10, air release valve. DETAILED DESCRIPTION

[0029] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatuses consistent with some aspects of the invention as detailed in the appended claims.

[0030] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0031] Example

[0032] A method for removing the ceramic core of a composite core blade for an aero-engine includes the following steps:

[0033] Step 1: Remove the ceramic core from the composite core blade of the aero-engine:

[0034] like Figure 1 As shown, the blades are spirally arranged and placed into the material bucket 5. The material bucket cover 4 is then closed, and the material bucket 5 is immersed in the reactor body 1. The sealing ring 3 is placed in the container and the upper plug 2 of the reactor body is fastened. When the blades are spirally arranged, the tenon is facing down. The reactor contains a potassium hydroxide solution with a concentration of 30% to 40%. The heating plate 9 is turned on to raise the temperature to 150°C to 170°C. The shut-off valve 8 is opened, and high-pressure inert gas of 0.1 MPa to 0.7 MPa is sprayed into the gas pipeline 7 through the one-way valve nozzle 6. After 6 minutes, the vent valve 10 is opened to release the high-pressure gas. This cycle is repeated for 12 hours. This step is used to remove the tenon and the silicon-based ceramic core in the composite core of the composite core blade and soften the silicon-based ceramic core in the composite core of the blade body.

[0035] Remove sealing ring 3 and upper plug 2, take out material bucket 5, rotate the blade position 180° and put it back into material bucket 5, put on material bucket cover 4, and perform the same process as above. This step is used to remove the silicon-based ceramic core in the blade composite core and soften the tenon and the aluminum-based ceramic core at the blade tip.

[0036] Step 2: Neutralize and clean the composite core blades of the aero-engine:

[0037] Remove sealing ring 3 and upper plug 2, take out material bucket 5, place the blade in citric acid with air stirring for 30 minutes to neutralize, and then place it in clean water with air stirring for 10 minutes to wash.

[0038] Step 3: Further remove the ceramic core from the composite core blades of the aero-engine;

[0039] Place the blade back into the material bucket 5, cover the material bucket with 4, immerse the material bucket and the lid into the vessel body 1 containing a 40%-60% potassium hydroxide solution, place the sealing ring 3 and tighten the upper plug 2, turn on the heating plate 9 to raise the temperature to 400℃~500℃, open the shut-off valve 8, and spray 20MPa~30MPa high-pressure inert gas through the gas pipeline 7 and the one-way valve nozzle 6. After 6 minutes, open the vent valve 10 to discharge the high-pressure gas. Repeat this cycle for 2 hours. This step is supercritical removal, used to remove the remaining aluminum-based ceramic core of the composite core blade.

[0040] Step 4: Clean and dry the composite core blades of the aero-engine.

[0041] The blades were flushed with high-pressure water for 5 minutes, and then placed in a drying oven at 120°C for 30 minutes.

[0042] Figure 2 The image shows the metallographic image of the blade after the composite core of the present invention has been removed. Figure 2 It can be seen that after removing the ceramic core of the composite core blade of the aero-engine using this method, there is no inter-corrosion. Therefore, the use of this invention can ensure both the efficiency and effectiveness of core removal, and also prevent corrosion of the blade.

[0043] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.

[0044] It should be understood that the present invention is not limited to the content already described above, and various modifications and changes can be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for removing the ceramic core of a composite core blade for an aero-engine, characterized in that, Includes the following steps: S1. Remove the ceramic core from the composite core blade of the aero-engine; S11. Place the blade in the reactor body (1). The reactor contains a 30%~40% potassium hydroxide solution. Turn on the heating plate (9) to raise the temperature to 150℃~170℃. Open the shut-off valve (8) and inject 0.1Mpa~0.7Mpa high-pressure inert gas through the gas pipeline (7) and the one-way valve nozzle (6). After 6 minutes, open the vent valve (10) to release the high-pressure gas. Repeat this cycle for 12 hours. S12. Flip the blade position obtained in S11 by 180° and perform the same process as in S11. S2. Neutralize and clean the composite core blades of the aero-engine that have been treated by S1. S3. Further removal of the ceramic core from the composite core blades of the aero-engine; Specifically: the blades obtained in S2 are placed back into the material bucket (5), the material bucket cover (4) is put on, the material bucket and the material bucket cover are immersed in the vessel body (1) containing a 40%-60% concentration of potassium hydroxide solution, the sealing ring (3) is put in and the upper plug (2) is fastened, the heating plate (9) is turned on to raise the temperature to 400℃~500℃, the shut-off valve (8) is opened, and high-pressure inert gas of 20MPa~30MPa is sprayed in through the gas pipeline (7) and the one-way valve nozzle (6). After 6 minutes, the vent valve (10) is opened to discharge the high-pressure gas. This cycle is repeated for 2 hours. S4. The composite core blades of the aero-engine that have been treated in S3 are cleaned and dried.

2. The method for removing the ceramic core of a composite core blade for an aero-engine according to claim 1, characterized in that, The process of placing the blades in the reactor in S11 is as follows: the blades are spirally arranged and placed into the material bucket (5), the material bucket cover (4) is closed, the material bucket (5) is then immersed in the reactor body (1), the sealing ring (3) is placed in and the upper plug (2) of the reactor body is fastened.

3. The method for removing the ceramic core of a composite core blade for an aero-engine according to claim 1, characterized in that, S12 specifically involves: removing the sealing ring (3) and the upper plug (2), taking out the material bucket (5), turning the blade 180° and putting it back into the material bucket (5), and putting the material bucket cover (4) on.

4. The method for removing the ceramic core of a composite core blade for an aero-engine according to claim 1, characterized in that, S2 specifically involves: removing the sealing ring (3) and the upper plug (2), taking out the material bucket (5), placing the blade in citric acid with air stirring to neutralize for 30 minutes, and then placing it in clean water with air stirring to wash for 10 minutes.

5. The method for removing the ceramic core of a composite core blade for an aero-engine according to claim 1, characterized in that, Specifically, S4 involves rinsing the inner cavity channel of the blade obtained in S3 with high-pressure water for 5 minutes, and then placing the blade in a drying oven at 120°C for 30 minutes.

6. The method for removing the ceramic core of a composite core blade for an aero-engine according to claim 2, characterized in that, When placing the blades in a spiral, the tenon should face downwards.

7. The method for removing the ceramic core of a composite core blade for an aero-engine according to claim 1, characterized in that, S11 is used to remove the silicon-based ceramic core in the composite core at the tenon and blade tip of the composite core blade and soften the silicon-based ceramic core in the composite core of the blade body; S12 is used to remove the silicon-based ceramic core in the composite core of the blade body and soften the aluminum-based ceramic core at the tenon and blade tip; S3 is supercritical removal, used to remove the remaining aluminum-based ceramic core of the composite core blade.

Images