Core removing method for ceramic core in semi-closed impact cavity of blade

Abstract

The invention belongs to the field of blade casting, and particularly relates to a depoling method for a ceramic core in a semi-closed impact cavity of a blade. According to the technical scheme, the core removing method for the ceramic core in the blade semi-closed impact cavity comprises the steps that firstly, a core removing channel is formed in the closed end of the blade semi-closed impact cavity; secondly, a NaOH solution is adopted for depoling; finally, a KOH solution is adopted for depoling. According to the method for removing the ceramic core in the semi-closed impact cavity of the blade, the ceramic core in the semi-closed impact cavity of the blade can be effectively removed.

Description

Technical Field

[0001] The invention belongs to the field of blade casting, and in particular relates to a method for removing a ceramic core in a semi-enclosed impact cavity of a blade. Background Art

[0002] Some blades of aircraft engines have semi-enclosed impact cavities. When casting the blades, a ceramic core is set in the inner cavity for molding, and the core needs to be removed after casting. Conventional core removal methods cannot remove the ceramic core in the semi-enclosed impact cavity of such blades. Summary of the invention

[0003] The invention provides a method for removing a ceramic core in a semi-enclosed impact cavity of a blade, which can effectively remove the ceramic core in the semi-enclosed impact cavity of the blade.

[0004] The technical solution of the present invention is as follows:

[0005] A method for removing the core of a ceramic core in a semi-enclosed impact cavity of a blade comprises the following steps: firstly, a core removal channel is opened at a closed end of the semi-enclosed impact cavity of the blade; secondly, a NaOH solution is used for core removal; and finally, a KOH solution is used for core removal.

[0006] Furthermore, the method for removing the core of the ceramic core in the semi-closed impact cavity of the blade opens a core removal channel at the closed end of the semi-closed impact cavity of the blade, specifically comprising: using electric spark equipment and a Φ0.9 through-hole electrode to open a Φ1 hole from the outside to the inside at the closed end of the semi-closed impact cavity of the blade, the front end face of the through-hole electrode is perpendicular to its own axis, the bottom of the hole is also perpendicular to its own axis, and a metal partition with a triangular cross-section is formed between the hole and the ceramic core; then, using a Φ0.9 forming electrode to remove the metal partition, and to connect the hole and the ceramic core to form a core removal channel, so that the semi-closed impact cavity of the blade becomes a non-closed state.

[0007] Furthermore, the core-removing method of the ceramic core in the semi-closed impact cavity of the blade adopts NaOH solution for core-removing, which specifically includes: the core-removing machine adopts 20% to 25% concentration of NaOH solution, and de-cores the ceramic core in the semi-closed impact cavity of the blade once every 8h to 10h at a temperature of 155℃ to 165℃ and a pressure of 0.5Mpa to 0.65Mpa, and de-cores 4 times in succession.

[0008] Furthermore, the core-removing method of the ceramic core in the semi-closed impact cavity of the blade adopts KOH solution core-removing, which specifically includes: the core-removing machine adopts 60% to 65% concentration of KOH solution, and the residual ceramic core in the semi-closed impact cavity of the blade is cored once every 4h to 6h at a temperature of 175°C to 180°C and a pressure of 0.5Mpa to 0.6Mpa, and the core-removing is performed twice in a row.

[0009] The beneficial effects of the present invention are as follows: the present invention opens a channel on the end face of the closed end of the semi-closed impact cavity of the blade, so that the semi-closed impact cavity of the blade becomes a non-closed impact cavity, forming a core removal circulation channel, which can effectively remove the ceramic core in the semi-closed impact cavity of the blade. Using a 20% to 25% concentration NaOH solution for continuous removal for 4 times can remove most of the core of the blade, reduce the degree of corrosion of the blade part body by the NaOH solution, and protect the physical state of the surface of the blade part intact. Using a 60% to 65% concentration KOH solution for continuous removal for 2 times can remove the residual core near the core removal channel in the semi-closed impact cavity of the blade part; finally, the core removal of the blade with a semi-closed impact cavity can be completed quickly and efficiently without causing excessive corrosion of the blade. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 A schematic diagram of a core stripping channel provided at a closed end of a semi-enclosed impact cavity of a blade;

[0011] Figure 2 for Figure 1 Enlarged view of point A in the middle; point B is the area where holes can be opened on the blade. DETAILED DESCRIPTION

[0012] A method for removing a ceramic core from a semi-enclosed impact cavity of a blade comprises the following steps:

[0013] First, a core removal channel 2 is opened at the closed end of the semi-enclosed impact cavity of the blade, such as Figure 1 , 2 As shown; using an electric spark device and a Φ0.9 through-hole electrode, a Φ1 hole 3 is opened from the outside to the inside at the closed end of the semi-enclosed impact cavity of the blade. Because the structural characteristics of the blade result in only a small area for opening a hole, an inclined hole can only be opened from the end face of the blade to the semi-enclosed impact cavity; the front end face of the through-hole electrode is perpendicular to its own axis, and the bottom of the hole 3 is also perpendicular to its own axis. Since the through-hole electrode cannot move forward after contacting the ceramic core 1, a metal barrier 4 with a triangular cross-section is formed between the hole 3 and the ceramic core 1; then, a Φ0.9 forming electrode is used to remove the metal barrier 4, and the hole 3 and the ceramic core 1 are connected to form a core removal channel 2, so that the semi-enclosed impact cavity of the blade becomes a non-enclosed state. First, opening a hole with a through-hole electrode and then removing the metal barrier 4 with a forming electrode can prevent the forming electrode from being quickly burned and deformed and unable to work, because the front end of the forming electrode is consistent with the structure of the metal barrier, which is difficult to manufacture and has high cost.

[0014] Secondly, NaOH solution is used for core removal; the core removal machine uses 25% NaOH solution, at a temperature of 160°C and a pressure of 0.6Mpa, to remove the ceramic core 1 in the semi-enclosed impact cavity of the blade once every 9 hours, and the core removal is repeated 4 times.

[0015] Finally, KOH solution is used for core removal; specifically, the core removal machine uses 60% KOH solution to remove the residual ceramic core 1 in the semi-closed impact cavity of the blade once every 4 hours at a temperature of 175°C and a pressure of 0.5Mpa, and the core removal is repeated twice in succession.

Claims

1. A method for removing a ceramic core from a semi-enclosed impact cavity of a blade, characterized in that: Firstly, a core removal channel is opened at the closed end of the semi-closed impact cavity of the blade; secondly, NaOH solution is used for core removal; finally, KOH solution is used for core removal.

2. The method for removing the ceramic core from the semi-enclosed impact cavity of a blade according to claim 1, characterized in that: A core-removing channel is opened at a closed end of a semi-closed impact cavity of a blade, specifically comprising: using an electric spark device and a Φ0.9 through-hole electrode to open a Φ1 hole from outside to inside at a closed end of the semi-closed impact cavity of the blade, wherein the front end surface of the through-hole electrode is perpendicular to its own axis, and the bottom of the hole is also perpendicular to its own axis, and a metal partition with a triangular cross-section is formed between the hole and the ceramic core; then, a Φ0.9 forming electrode is used to remove the metal partition, and the core-removing channel is formed by connecting the hole and the ceramic core, so that the semi-closed impact cavity of the blade becomes a non-closed state.

3. The method for removing the ceramic core from the semi-enclosed impact cavity of a blade according to claim 1, characterized in that: The core removal is carried out by using NaOH solution, specifically including: a core removal machine uses 20% to 25% NaOH solution to remove the ceramic core in the semi-enclosed impact cavity of the blade once every 8 hours to 10 hours at a temperature of 155° C. to 165° C. and a pressure of 0.5 MPa to 0.65 MPa, and the core removal is carried out four times in a row.

4. The method for removing the ceramic core from the semi-enclosed impact cavity of a blade according to claim 1, characterized in that: The core removal is carried out by using KOH solution, specifically including: a core removal machine uses a 60% to 65% concentration of KOH solution, and at a temperature of 175°C to 180°C and a pressure of 0.5Mpa to 0.6Mpa, the residual ceramic core in the semi-closed impact cavity of the blade is removed once every 4h to 6h, and the removal is repeated twice in succession.

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