A turbine hollow blade investment casting device

Abstract

This invention discloses a lost-wax casting device for hollow turbine blades, comprising a sand box, a sand mold fixedly connected to the inner wall of the sand box, and protective frames connected to opposite sides of two sand boxes. An insert plate is fixedly connected to the bottom surface of the upper protective frame, and a fixed frame is fixedly connected to the top surface of the lower protective frame. The insert plate is inserted into the interior of the fixed frame. The upper protective frame is divided into two half-frames from the middle, and an adjustment component is connected between the two half-frames. A protective cover is fixedly connected to the top surface of the left half-frame. A protective plate is connected between the sand mold and the adjustment component, and side plates are fixedly connected between adjacent fixed frames. The protective plate limits the movement of the sand mold, preventing protrusions and ensuring a uniform wall thickness after casting, preventing unevenness. The top-mounted protective frame, divided into two half-frames, facilitates disassembly.

Description

Technical Field

[0001] This invention relates to the field of casting technology, and in particular to a casting apparatus for hollow turbine blades. Background Technology

[0002] Background Technology: Hollow turbine blades are core load-bearing components of gas turbines and steam turbines. The parts have complex shapes and internal cooling cavities, and the requirements for dimensional accuracy and surface quality are stringent. The mainstream method is to use investment casting for forming. Investment casting uses a wax model as a prototype, and a multi-layer refractory slurry is coated to prepare an integral ceramic shell. After dewaxing and firing, high-temperature alloy liquid is poured into the inner cavity of the shell. After cooling, the shell is broken to obtain the blade blank.

[0003] In the module assembly, shell firing, and alloy casting processes, when the rigidity of the inner cavity support structure of the hollow blade wax mold is insufficient and the shell lacks lateral positioning constraints, the wax mold is prone to deformation, and the ceramic shell is displaced and locally cracked due to the impact of high-temperature alloy liquid. The infiltration of high-temperature alloy liquid into the cracks will cause the blade's inner cavity dimensions to be out of tolerance, the wall thickness to be uneven, and the surface sand adhesion defects, which will significantly increase the cost of subsequent grinding and CNC machining, and in severe cases, directly lead to the scrapping of the blade. Existing conventional investment casting tooling lacks a lateral limiting and shaping structure for slender hollow blades, which cannot stably constrain the module and the shell, resulting in a low yield rate of molded products. Summary of the Invention

[0004] The purpose of this invention is to provide a casting wall thickness uniformity control device and control process, which can solve the problem that due to the lack of a limiting structure and the resulting insufficient or uneven overall compaction of the sand box, the parts with insufficient surface strength of the molding sand are prone to local expansion or damage under the action of static and dynamic pressure of molten metal.

[0005] According to the technical solution provided by the present invention: a steam turbine hollow blade investment casting device includes a sand box, a sand mold fixedly connected to the inner wall of the sand box, and protective frames connected to opposite sides of the two sand boxes. An insert plate is fixedly connected to the bottom surface of the upper protective frame, and a fixed frame is fixedly connected to the top surface of the lower protective frame. The insert plate is inserted into the interior of the fixed frame. The upper protective frame is divided into two half-frames from the middle. An adjustment component is connected between the two upper half-frames. A protective cover is fixedly connected to the top surface of the left half-frame. A protective plate is connected between the sand mold and the adjustment component. Side plates are fixedly connected between adjacent fixed frames.

[0006] Preferably, the adjustment component includes a first limiting plate, which is fixedly connected to the inner wall of the left half-frame. The bottom surface of the right half-frame has a slot that matches the first limiting plate. A threaded rod is slidably connected to the inner wall of the first limiting plate. A contact plate is fixedly connected to the bottom surface of the threaded rod. A pressing plate is slidably connected to the top surface of the contact plate. An adjustment disc is threadedly connected to the outer wall of the threaded rod.

[0007] Preferably, an isolation plate is fixedly connected to the bottom surface of the sand box, and the isolation plate is slidably connected to the contact plate.

[0008] Preferably, a plurality of pull plates are connected between the protective frame and the sand mold, the pull plates are fixedly connected to the corner of the sand mold, and the inner wall of the protective frame is provided with a groove that matches the pull plates.

[0009] Preferably, a fixing unit is connected inside the side plate. The fixing unit includes a rotating shaft that rotates the inner wall of the side plate. A gear is fixedly connected to the outer wall of the fixing unit. A second limiting plate is slidably connected to the outer wall of the rotating shaft through a tooth groove. A tooth groove matching the gear is opened on the outer wall of the insert plate.

[0010] Preferably, the outer wall of the insert plate is provided with a slot that matches the second limiting plate, and a slanted slot is provided on one side between the slot and the insert plate.

[0011] The investment casting apparatus for hollow turbine blades provided in this invention has the following advantages:

[0012] 1. The protective plate limits the movement of the sand mold, preventing bulges and ensuring uniform wall thickness after casting, preventing uneven shapes. The top protective frame is divided into two halves for easy disassembly. If the protective plate needs replacement due to excessive metal residue affecting subsequent pouring, it can be easily replaced by disassembling the two halves. The operation is simple, and the two halves make disassembly easy.

[0013] 2. When the surface of the sand mold deforms after prolonged use, or when different sand boxes are used, resulting in inconsistent thickness of the sand mold, the position of the protective plate needs to be adjusted.

[0014] 3. The rotating shaft inserts the second limiting plate into the interior of the insert plate, thereby fixing the position between the fixed frame and the insert plate, providing space for the movement of the second limiting plate, and fixing and limiting the position between the second limiting plate and the insert plate. Attached Figure Description

[0015] Figure 1 This is a three-dimensional structural diagram of the present invention.

[0016] Figure 2 This is a schematic diagram of the three-dimensional structure of the fixed unit of the present invention.

[0017] Figure 3 This is a schematic diagram of the cross-sectional structure of the present invention (right view).

[0018] Figure 4 for Figure 3 Enlarged structural diagram at point A in the middle.

[0019] Figure 5 This is a front view sectional structural diagram of the present invention.

[0020] Figure 6 This is a cross-sectional view of the fixed unit structure of the present invention.

[0021] Figure descriptions: 1. Sand box; 2. Protective frame; 21. Half frame; 3. Fixing frame; 4. Insert plate; 5. Protective cover; 6. Adjusting assembly; 61. First limiting plate; 62. Threaded rod; 63. Adjusting disc; 64. Extrusion plate; 65. Contact plate; 66. Isolation plate; 7. Side plate; 8. Protective plate; 9. Sand mold; 10. Pull plate; 11. Fixing unit; 111. Rotating shaft; 112. Gear; 113. Second limiting plate; 114. Slot. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0023] like Figures 1-6 As shown, the present invention is a steam turbine hollow blade investment casting device, including a sand box 1, a sand mold 9 fixedly connected to the inner wall of the sand box 1, protective frames 2 connected to opposite sides of the two sand boxes 1, an insert plate 4 fixedly connected to the bottom surface of the upper protective frame 2, a fixed frame 3 fixedly connected to the top surface of the lower protective frame 2, the insert plate 4 being inserted into the interior of the fixed frame 3, the upper protective frame 2 being divided into two half-frames 21 from the middle, an adjustment component 6 being connected between the two upper half-frames 21, a protective cover 5 fixedly connected to the top surface of the left half-frame 21, a protective plate 8 being connected between the sand mold 9 and the adjustment component 6, and side plates 7 being fixedly connected between adjacent fixed frames 3;

[0024] Specifically, when using this device, it is necessary to place the device in the processing position, place the overall protective frame 2 at the bottom, place the protective plate 8 on the top surface of the protective frame 2, and then arrange the combination structure of sand box 1 and sand mold 9. Next, place the upper protective plate 8 on the top of the sand mold 9, then insert the right protective frame 2 with the fixing frame 3 into the inside of the fixing frame 3, and then insert the right protective frame 2 with the insert plate 4 into the inside of the fixing frame 3. By setting the structure of the protective plate 8, the top surface position of the sand mold 9 is restricted, so that when the high temperature solution enters the inside of the sand mold 9 through the feed port for pouring;

[0025] The protective plate 8 is used to limit the movement and prevent the sand mold 9 from protruding, thus ensuring that the wall thickness remains uniform after casting and that there are no uneven shapes. The protective frame 2 at the top is divided into two half-frames 21, which are easy to disassemble. When a lot of metal material adheres to the surface of the protective plate 8 during long-term casting and affects subsequent casting, and it needs to be replaced, the protective plate 8 can be replaced by disassembling the two half-frames 21 one after the other. The operation is simple and the combination of the two half-frames 21 makes it easy to disassemble.

[0026] Preferably, the adjusting component 6 includes a first limiting plate 61, which is fixedly connected to the inner wall of the left half-frame 21. The bottom surface of the right half-frame 21 is provided with a slot that matches the first limiting plate 61. A threaded rod 62 is slidably connected to the inner wall of the first limiting plate 61. A contact plate 65 is fixedly connected to the bottom surface of the threaded rod 62. A pressing plate 64 is slidably connected to the top surface of the contact plate 65. An adjusting disc 63 is threadedly connected to the outer wall of the threaded rod 62. An isolation plate 66 is fixedly connected to the bottom surface of the sand box 1. The isolation plate 66 is slidably connected to the contact plate 65.

[0027] Specifically, by setting the structure of the adjustment component 6, when the surface of the sand mold 9 deforms after long-term use, or when different sand boxes are used and the thickness of the sand mold 9 becomes inconsistent, it is necessary to adjust the position of the protective plate 8. This can be achieved by turning the structure of the adjustment disc 63, which rotates the adjustment disc 63. The rotation of the adjustment disc 63, in conjunction with the threaded engagement, moves the threaded rod 62 downward. The threaded rod 62 drives the contact plate 65 downward, squeezing the protective plate 8, thereby squeezing the protruding parts and ensuring that the wall thickness of the casting remains uniform during the pouring process. The position of the protective plate 8 can be adjusted by replacing the structure of the extrusion plate 64. The isolation plate 66 structure prevents the adhesion of molten metal from making the adjustment component 6 difficult to adjust, thus ensuring the integrity of the structure during use.

[0028] Preferably, multiple pull plates 10 are connected between the protective frame 2 and the sand mold 9. The pull plates 10 are fixedly connected to the corner of the sand mold 9, and the inner wall of the protective frame 2 is provided with a slot that matches the pull plates 10.

[0029] Specifically, by setting the structure of the pull plate 10, the connection between the protective plate 8 and the protective frame 2 is increased, so that after the structure of the protective frame 2 is assembled, the corner of the protective plate 8 is pulled and fixed by the pull plate 10, maintaining the pressure of the protective plate 8 on the sand mold 9, thereby ensuring that the wall thickness of the casting formed by the pressure of the protective plate 8 is uniform.

[0030] Preferably, a fixing unit 11 is connected inside the side plate 7. The fixing unit 11 includes a rotating shaft 111. The rotating shaft 111 rotates the inner wall of the side plate 7. A gear 112 is fixedly connected to the outer wall of the fixing unit 11. A second limiting plate 113 is slidably connected to the outer wall of the rotating shaft 111 through a tooth groove. A tooth groove matching the gear 112 is opened on the outer wall of the insert plate 4. A slot 114 matching the second limiting plate 113 is opened on the outer wall of the insert plate 4. An oblique slot is provided on one side between the slot 114 and the insert plate 4.

[0031] Specifically, by setting the structure of the fixing unit 11, when the left protective frame 2 drives the insert plate 4 to be inserted into the interior of the fixing frame 3, the gear 112 is driven to rotate through the tooth groove on the surface of the insert plate 4. The rotation of the gear 112 drives the rotating shaft 111 to rotate. During the rotation, the rotating shaft 111 inserts the second limiting plate 113 into the interior of the insert plate 4 through the cooperation of the gear and tooth groove between the rotating shaft 111 and the second limiting plate 113, so that the position between the fixing frame 3 and the insert plate 4 is fixed. By opening the slot 114 on the surface of the insert plate 4, space is provided for the movement of the second limiting plate 113, and the second limiting plate 113 and the insert plate 4 are fixed and limited.

[0032] The work process is as follows:

[0033] In use, first place the overall protective frame 2 in the processing position, place the combined structure of sand box 1 and sand mold 9 inside the protective frame 2, and place the protective plate 8 on top of the sand mold 9. Then, insert the insert plate 4 of the right protective frame 2 into the left fixed frame 3 to achieve the initial connection of the upper and lower protective frames 2. During the insertion of the insert plate 4, the tooth groove on its outer wall drives the gear 112 to rotate, which in turn drives the rotating shaft 111 to rotate. Through the meshing of the gears, the second limiting plate 113 is inserted into the slot 114 of the insert plate 4 to achieve automatic locking of the fixed frame 3 and the insert plate 4, ensuring a stable connection.

[0034] The protective plate 8 is located on top of the sand mold 9 and is used to restrict the flow of molten metal during pouring, prevent local bulging of the sand mold 9, and ensure uniform wall thickness of the casting. When the sand mold 9 is deformed due to long-term use or when a sand mold of different thickness is replaced, it can be compensated and adjusted by adjusting component 6. Turning the adjusting plate 63 will drive the threaded rod 62 to move down, pushing the contact plate 65 and the extrusion plate 64 to apply pressure to the protective plate 8 to achieve the limit. The isolation plate 66 prevents molten metal from adhering and affecting the operation of the adjusting component 6.

[0035] The pull plate 10 enhances the connection strength between the protective plate 8 and the protective frame 2, ensuring uniform pressure transmission. The upper protective frame 2 adopts a double half-frame 21 structure, which facilitates the disassembly and replacement of the protective plate 8 with attached metal objects. The overall structure is easy to operate and effectively improves the casting quality and equipment maintenance efficiency.

[0036] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, and the present invention is not limited thereto; for those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A device for investment casting of hollow turbine blades, characterized in that, The system includes a sand box (1), a sand mold (9) is fixedly connected to the inner wall of the sand box (1), and protective frames (2) are connected to opposite sides of the two sand boxes (1). A plate (4) is fixedly connected to the bottom surface of the upper protective frame (2), and a fixed frame (3) is fixedly connected to the top surface of the lower protective frame (2). The plate (4) is inserted into the interior of the fixed frame (3). The upper protective frame (2) is divided into two half-frames (21) from the middle. An adjustment component (6) is connected between the two upper half-frames (21). A protective cover (5) is fixedly connected to the top surface of the left half-frame (21). A protective plate (8) is connected between the sand mold (9) and the adjustment component (6). A side plate (7) is fixedly connected between adjacent fixed frames (3).

2. The investment casting apparatus for hollow turbine blades as described in claim 1, characterized in that: The adjustment component (6) includes a first limiting plate (61), which is fixedly connected to the inner wall of the left half-frame (21). The bottom surface of the right half-frame (21) is provided with a slot that matches the first limiting plate (61). A threaded rod (62) is slidably connected to the inner wall of the first limiting plate (61). A contact plate (65) is fixedly connected to the bottom surface of the threaded rod (62). A pressing plate (64) is slidably connected to the top surface of the contact plate (65). An adjustment disc (63) is threadedly connected to the outer wall of the threaded rod (62).

3. The investment casting apparatus for hollow turbine blades as described in claim 2, characterized in that, The bottom surface of the sand box (1) is fixedly connected to an isolation plate (66), and the isolation plate (66) is slidably connected to the contact plate (65).

4. The investment casting apparatus for hollow turbine blades as described in claim 1, characterized in that: Multiple pull plates (10) are connected between the protective frame (2) and the sand mold (9). The pull plates (10) are fixedly connected to the corner of the sand mold (9). The inner wall of the protective frame (2) is provided with a slot that matches the pull plates (10).

5. The investment casting apparatus for hollow turbine blades as described in claim 1, characterized in that: The side plate (7) is internally connected to a fixing unit (11), which includes a rotating shaft (111). The rotating shaft (111) rotates the inner wall of the side plate (7). A gear (112) is fixedly connected to the outer wall of the fixing unit (11). A second limiting plate (113) is slidably connected to the outer wall of the rotating shaft (111) through a tooth groove. The outer wall of the insert plate (4) is provided with a tooth groove that matches the gear (112).

6. The investment casting apparatus for hollow turbine blades as described in claim 5, characterized in that: The outer wall of the insert plate (4) is provided with a slot (114) that matches the second limiting plate (113), and a slanted slot is provided on one side between the slot (114) and the insert plate (4).

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