Shell making method of cartridge receiver investment precision casting cavity

Abstract

The invention relates to the technical field of investment casting, in particular to a shell making method of a cartridge receiver investment precision casting cavity, which comprises the following steps: S1, pressing a wax mold of a cartridge receiver; s2, forming a process hole in the side wall of the cavity of the wax mold; s3, performing shell making on the cavity; s4, the interior of the cavity is filled with mullite sand; s5, plugging the opening part of the cavity; and S6, overall back layer shell making is conducted on the cartridge receiver. Compared with a ceramic core, the shell making method provided by the invention is more flexible in pipeline forming, and the casting manufacturability difficulty is reduced; the defects that cleaning is difficult and use is limited are overcome, the surface quality of castings is guaranteed, the production period is shortened, and the production cost of the castings is saved; the shell manufacturing method provided by the invention is suitable for manufacturing a narrow long cavity in a large titanium alloy casing investment casting, the quality of the shell in the narrow long cavity is ensured, the strength meets the later smelting and pouring requirements, and the narrow long cavity forming rate is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of investment casting, and in particular to a shell making method for a casing investment precision casting cavity. Background Art

[0002] Figure 1 The structure of the casing cavity is shown in the figure. The casing cavity is a narrow and long cavity structure of a titanium alloy casting. In the alloy investment casting production technology, the traditional narrow and long cavity of titanium alloy castings is mainly formed by ceramic core molding. The ceramic core molding process will have the following problems in the actual operation process:

[0003] (1) The ceramic core that forms the inner cavity is difficult to remove due to its high strength, and the inner wall of the narrow and long cavity is easily damaged during the cleaning process;

[0004] (2) The ceramic core is easily broken and deviated under the violent impact of titanium liquid, resulting in uneven wall thickness, undercasting and spark leakage in narrow and long cavities of castings;

[0005] (3) The ceramic core is difficult to position in the mold and is prone to eccentricity or breakage;

[0006] (4) The ceramic core and shell are made of different materials. During the later firing of the shell, due to the different thermal expansion coefficients, the ceramic core breaks after being stressed.

[0007] (5) The ceramic core material is easy to react with titanium alloy, and after casting, there are many reactive pores in the narrow and long cavity. Summary of the invention

[0008] The main purpose of the present invention is to propose a shell making method for a casing investment casting cavity, so as to reduce the problems of spark leakage and under-casting caused by insufficient shell strength inside the cavity during the pouring process, and to improve the shell strength to meet the later smelting and pouring requirements.

[0009] To achieve the above object, the present invention provides a shell making method for a casing investment casting cavity, the steps comprising:

[0010] S1, wax mold of the receiver;

[0011] S2, opening a process hole on the side wall of the wax mold cavity;

[0012] S3, shelling the cavity;

[0013] S4, filling the cavity with mullite sand;

[0014] S5, sealing the mouth of the cavity;

[0015] S6. Make the overall back shell of the receiver.

[0016] Preferably, in step S3, when shell making is performed, shell making of the surface layer, shell making of the transition layer and shell making of the entire casing are performed simultaneously.

[0017] Preferably, in step S4, the filling is performed after the transition layer shell is made and the inside of the cavity is completely dried.

[0018] Preferably, in step S4, 70-mesh mullite sand is used for filling.

[0019] Preferably, in step S5, the cavity mouth is sealed by mixing mullite sand, bauxite powder and adhesive.

[0020] Preferably, the binder is silica sol.

[0021] Preferably, the number of process holes on each side wall is at least two.

[0022] Preferably, the number of process holes on each side wall is two, and the two process holes are respectively arranged at diagonal positions of the side wall.

[0023] Preferably, in step S1, after the wax mold is pressed, the surface of the wax mold is cleaned to remove burrs.

[0024] Preferably, the method further comprises step S7 of heating and dewaxing the integral shell prepared in step S6.

[0025] Due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows:

[0026] (1) The shell making method provided by the present invention is more flexible than the ceramic core in forming the pipeline, and reduces the difficulty of the casting process.

[0027] (2) The shell making method provided by the present invention overcomes the disadvantages of difficult cleaning and limited use, ensures the surface quality of the casting, shortens the production cycle, and saves the production cost of the casting.

[0028] (3) The shell making method provided by the present invention is suitable for forming a narrow long cavity in a titanium alloy large casing investment casting. The quality of the shell inside the narrow long cavity is guaranteed, the strength meets the requirements of later smelting and pouring, and the forming rate of the narrow long cavity is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0030] Figure 1 It is a schematic diagram of the cavity structure of the casing;

[0031] Figure 2 It is a schematic diagram of opening a process hole on the side wall of the cavity of the wax mold in the present invention;

[0032] Figure 3 It is a structural schematic diagram of shell making of the cavity in the present invention;

[0033] Figure 4 is a schematic diagram of filling the cavity in the present invention;

[0034] Figure 5 It is a schematic diagram of sealing the cavity mouth in the present invention. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0037] Combination Figures 1 to 5 As shown, a shell making method for a casing investment casting cavity comprises the following steps:

[0038] S1. Press the wax mold of the receiver. After the wax mold is pressed, clean the surface of the wax mold to remove burrs.

[0039] S2. Open process holes on the side wall of the wax mold cavity. The diameter of the process holes can be adjusted according to the actual situation of the casing. The purpose of opening the process holes is to improve the strength of the later cavity shell. In this embodiment, the number of process holes on each side wall is two, and the two process holes are respectively arranged at diagonal positions of the side wall.

[0040] S3. Shelling the cavity. When shelling, shelling of the surface layer, shelling of the transition layer and shelling of the entire casing are carried out simultaneously.

[0041] S4, filling the cavity with mullite sand, after the transition layer shell is completed and the cavity is completely dried, the filling is performed. Specifically, 70 mesh mullite sand is used for filling.

[0042] S5. The mouth of the cavity is blocked to prevent the internal sand from falling out during the rotation process and the later pouring. Specifically, mullite sand, bauxite powder and adhesive are mixed to block the mouth of the cavity. In this embodiment, the adhesive is silica sol. Silica sol can increase the shell strength, improve the casting finish, shorten the drying time, and enhance the high temperature strength and thermal shock stability.

[0043] S6. Make the overall back shell of the receiver.

[0044] S7, heating and dewaxing the integral shell prepared in step S6.

[0045] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for making a casing of a casing investment casting cavity, characterized in that the steps include: S1, wax mold of the pressing receiver; S2, opening a process hole on the side wall of the wax mold cavity; S3, shelling the cavity; S4, filling the cavity with mullite sand; S5, sealing the mouth of the cavity; S6. Make the overall back shell of the receiver.

2. A shell making method for a casing investment casting cavity as claimed in claim 1, characterized in that: In step S3, when shell making is performed, the surface layer shell making, the transition layer shell making and the overall casing shell making are performed simultaneously.

3. A shell making method for a casing investment casting cavity as claimed in claim 2, characterized in that: In step S4, filling is performed after the transition layer shell is made and the inside of the cavity is completely dried.

4. The method for making a shell of a casing investment casting cavity according to claim 1, characterized in that: In the step S4, 70-mesh mullite sand is used for filling.

5. The method for making a shell of a casing investment casting cavity according to claim 1, characterized in that: In the step S5, the mouth of the cavity is sealed by mixing mullite sand, bauxite powder and adhesive.

6. The method for making a shell of a casing investment casting cavity according to claim 1, characterized in that: The binder is silica sol.

7. The method for making a casing of a casing investment casting cavity according to claim 1, characterized in that: The number of process holes on each side wall is at least two.

8. The method for making a shell of a casing investment casting cavity according to claim 1, characterized in that: The number of process holes on each side wall is two, and the two process holes are respectively arranged at diagonal positions of the side wall.

9. The method for making a shell of a casing investment casting cavity according to claim 1, characterized in that: In step S1, after the wax mold is pressed, the surface of the wax mold is cleaned to remove burrs.

10. The method for making a shell of a casing investment casting cavity according to claim 1, characterized in that: The method further comprises step S7 of heating and dewaxing the integral shell prepared in step S6.

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