Single crystal or directionally solidified casting slag-free pouring structure and method

Abstract

The application discloses a single crystal or directional solidification casting non-dross pouring structure and method, which aims to effectively prevent dross from flowing into a casting cavity and reduce inclusions in the casting. To this end, the single crystal or directional solidification casting non-dross pouring structure comprises a directional solidification furnace and a ceramic mold shell, the ceramic mold shell is placed on a lifting platform of the directional solidification furnace, the directional solidification furnace has a hot chamber and a cold chamber, the top of the ceramic mold shell is provided with a pouring cup, an intermediate ladle is arranged on the top of the hot chamber and located directly above the pouring cup, a plug is arranged in the funnel mouth of the intermediate ladle, a top block is arranged on the ceramic mold shell and aligned with the plug, and the top block can push the plug away during the lifting of the ceramic mold shell on the hot chamber, so that the purified alloy liquid in the intermediate ladle flows into the pouring cup through the funnel mouth.

Description

Technical Field

[0001] This invention belongs to the field of investment casting technology, and particularly relates to a slag-free casting structure and method for single-crystal or directional solidification castings. Background Technology

[0002] The existing manufacturing process for single-crystal or directional castings typically includes the following steps: pressing wax patterns → assembling wax patterns → preparing the mold shell → melting and casting to obtain single-crystal or directional castings. During the alloy melting and casting process, casting is achieved by tilting the crucible, and the slag floating on the alloy liquid is first poured into the mold shell casting cavity. Since even with a filter screen, these liquid inclusions cannot be prevented, inclusion defects are inevitable in the casting. Summary of the Invention

[0003] The main objective of this invention is to provide a slag-free casting structure and method for single-crystal or directional solidification castings, which aims to effectively prevent slag from flowing into the casting cavity and reduce inclusion defects in the casting.

[0004] To address this, the present invention provides a slag-free casting structure for single-crystal or directionally solidified castings, comprising a directionally solidified furnace and a ceramic mold shell. The ceramic mold shell is placed on a lifting platform of the directionally solidified furnace, which has a hot chamber and a cold chamber. The top of the ceramic mold shell is equipped with a pouring cup. An tundish funnel is installed on the top of the hot chamber, directly above the pouring cup. A plug is provided in the spout of the tundish funnel. A top block aligned with the plug is installed on the ceramic mold shell. When the lifting platform moves the ceramic mold shell upward within the hot chamber, the top block can push open the plug, allowing the molten alloy in the tundish funnel to flow into the pouring cup through the spout.

[0005] Specifically, a stopper rod is formed below the plug, extending out of the funnel and cooperating with the top block. The plug on the upper part of the stopper rod and the funnel are in conical contact, forming a leakage gap when they separate.

[0006] Specifically, the top block is fixedly installed in the pouring cup.

[0007] Specifically, when the lifting platform moves the ceramic mold shell downward in the hot chamber, the blockage can automatically reset and reseal the funnel nozzle.

[0008] Specifically, the plug is a conical ceramic plug, and the top block is a long strip-shaped ceramic block, which does not obstruct the flow of the alloy liquid.

[0009] Specifically, the ceramic mold shell has a pouring channel and a casting cavity, and the pouring port of the pouring cup is connected to the casting cavity through the pouring channel.

[0010] Specifically, the pouring port of the pouring cup is directly aligned with the vertical central column tube that connects to the ceramic mold shell, and multiple casting cavities are evenly distributed around the vertical central column tube. Each casting cavity is connected to the upper side of the vertical central column tube through a pouring channel.

[0011] Specifically, the top of the hot chamber is provided with a furnace cover that can be opened and closed and can cover the intermediate ladle funnel.

[0012] Specifically, the ceramic mold shell and the pouring cup are integrally formed.

[0013] In another aspect, the present invention provides a slag-free casting method for single-crystal or directionally solidified castings, employing the above-mentioned slag-free casting structure, comprising the following steps:

[0014] (1) The ceramic mold shell is raised into the first position of the hot chamber using a lifting platform for preheating, and the alloy material is melted using a crucible;

[0015] (2) Pour the molten alloy into the tundish funnel and let it stand for a certain period of time to allow the inclusions to float to the surface of the molten pool.

[0016] (3) The ceramic mold shell is raised to the second position of the hot chamber by using the lifting platform. During this process, the top block will push the block upward to open the funnel nozzle of the intermediate package funnel.

[0017] (4) The molten alloy flows into the ceramic mold through the funnel nozzle to fill the mold. The inclusions floating on the surface of the molten pool eventually flow down and float on the surface of the liquid in the pouring cup, without entering the casting cavity.

[0018] (5) Then the ceramic mold shell is lowered from the hot chamber to the cold chamber, and the molten metal in the mold shell completes directional solidification.

[0019] Compared with the prior art, at least one embodiment of the present invention has the following beneficial effects:

[0020] 1. Prevent slag from flowing into the mold cavity and reduce inclusions in the casting;

[0021] 2. Reduce the pouring drop to prevent molten metal from splashing and ensure smooth filling, thus protecting the core;

[0022] 3. It can precisely control the purification time of the molten metal in the tundish, so that the inclusions can float to the surface. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the ceramic mold shell being preheated in a directional solidification furnace according to an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of the crucible pouring molten alloy into the tundish funnel provided in an embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the ceramic mold shell driving the top block to move upward, provided in an embodiment of the present invention;

[0027] Figure 4 This is a schematic diagram of how the ceramic mold shell drives the top block to move upward, opening the blockage and punching the shape, provided in an embodiment of the present invention;

[0028] Figure 5 This is a schematic diagram of the directional solidification of a ceramic mold during descent, provided in an embodiment of the present invention;

[0029] The components are: 1. Ceramic mold shell; 2. Lifting platform; 3. Hot chamber; 4. Cold chamber; 5. Pour cup; 6. Tundish funnel; 7. Block; 8. Top block; 9. Plug rod; 10. Furnace cover; 11. Pour channel; 12. Casting cavity; 13. Vertical central column tube; 14. Inclusions; 15. Alloy liquid; 16. Crucible. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 are within the scope of protection of the present invention.

[0031] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0033] See Figure 1 A slag-free casting structure for single-crystal or directionally solidified castings includes a directionally solidified furnace and a ceramic mold shell 1. The ceramic mold shell 1 is placed on a lifting platform 2 of the directionally solidified furnace. The directionally solidified furnace has a hot chamber 3 and a cold chamber 4. The top of the ceramic mold shell 1 is equipped with a pouring cup 5. A tundish funnel 6 is installed on the top of the hot chamber 3, directly above the pouring cup 5. A plug 7 is provided in the spout of the tundish funnel 6. A top block 8 is installed on the ceramic mold shell 1, aligned with the plug 7. When the lifting platform 2 moves the ceramic mold shell 1 up in the hot chamber 3, the top block 8 can push open the plug 7, allowing the alloy liquid 15 in the tundish funnel 6 to flow into the pouring cup 5 through the spout. The directionally solidified furnace is a vacuum furnace. The specific structure of the directionally solidified furnace is existing technology and will not be described in detail here.

[0034] See Figures 1-5 When casting single-crystal high-temperature alloys using the above-mentioned slag-free casting structure, the ceramic mold shell 1 is first placed on the water-cooled plate of the lifting platform 2. The lifting platform 2 is used to raise the ceramic mold shell 1 to the first position of the hot chamber 3 for preheating, and the alloy material is melted using the crucible 16. Then, the alloy liquid is poured into the tundish funnel 6 and left to stand for a set time to allow inclusions 14 (slag) to float to the surface, thus achieving the purification of the alloy liquid (purification process, about 1-3 minutes). After purification, the lifting platform 2 is used to drive the ceramic mold shell 1 to continue rising to the second position of the hot chamber 3. During this process, the top block 8 pushes the plug 7 to open the funnel nozzle of the tundish funnel 6. After the funnel nozzle is opened, the alloy liquid will flow into the pouring cup 5 along the funnel nozzle, and finally complete the mold shell filling. The inclusions will flow down last and float on the surface of the liquid in the pouring cup 5, without entering the casting cavity 12. Finally, the ceramic mold shell 1 is lowered from the hot chamber 3 to the cold chamber 4 to complete directional solidification.

[0035] This embodiment has the following advantages: 1) It prevents slag from flowing into the mold cavity and reduces inclusions in the casting; 2) It reduces the pouring drop, prevents molten liquid from splashing, ensures stable filling, and protects the core; 3) It can precisely control the purification time of the molten metal in the tundish.

[0036] Understandably, in practical applications, when the lifting platform 2 drives the ceramic mold shell 1 to move downward in the hot chamber 3, the blockage 7 can automatically reset and re-seal the funnel nozzle. This design allows the furnace cover 10 to be opened directly and the alloy liquid poured into the intermediate ladle funnel 6 during the next pouring, so that the alloy liquid can be allowed to stand and be purified without the need to replace the new blockage 7, resulting in high work efficiency.

[0037] Specifically, in order to effectively ensure the sealing performance of the plug 7, a stopper rod 9 is formed below the plug 7, extending outwards from the funnel and cooperating with the top block 8. The plug 7 and the funnel are in conical contact, forming a leakage gap when separated. When the lifting platform 2 drives the ceramic mold shell 1 to rise to the second position, the top block 8 pushes the stopper rod 9, opening the plug 7, and the alloy liquid leaks out from the leakage gap between the stopper rod 9 and the funnel.

[0038] In this embodiment, the stopper rod 9 is suspended below the plug 7. The suspension force provided by the stopper rod 9 secures the plug 7 to the funnel nozzle, ensuring the reliability of the seal and effectively preventing the molten alloy from washing away the plug during pouring, thus preventing seal failure. Simultaneously, the plug 7 and the funnel nozzle have a conical contact surface. When the lifting platform 2 moves the ceramic mold shell 1 downwards, causing the top block 8 to detach from the plug 7, the plug 7 can automatically reattach itself to the funnel nozzle under the suspension force provided by the stopper rod 9. Of course, the plug 7 can also automatically reset itself due to its own gravity.

[0039] Specifically, the top block 8 can be fixedly and horizontally installed in the pouring cup 5. The plug 7 and the stopper rod 9 can be manufactured as a single piece. The material of the top block 8 and the stopper rod 9 can be the same as that of the casting ceramic core, such as alumina ceramic. Of course, the plug 7 and the stopper rod 9 can also be manufactured separately and then fixedly connected. In this case, the plug can be designed as a cone shape, and the top block can be designed as a long strip shape so as not to obstruct the flow of the alloy liquid.

[0040] It should be explained that, in the actual design, a furnace cover 10, which can be opened and closed and can cover the tundish funnel 6, can be added to the top of the hot chamber 3. The furnace cover 10 has an insulation layer on the inside. During the purification process of the alloy liquid, the furnace cover 10 covers the top of the tundish funnel 6 to prevent heat loss. In addition, in order to reduce the manufacturing cost, the ceramic mold shell 1 and the pouring cup 5 are integrally molded. That is, the ceramic mold shell 1 is obtained by preparing the wax model of the pouring channel, the wax model of the casting cavity, and the wax model of the pouring cup, assembling the mold, and then making the shell.

[0041] See Figure 1In some embodiments, the ceramic mold shell 1 has a pouring channel 11 and a casting cavity 12. The pouring port of the pouring cup 5 is connected to the casting cavity 12 through the pouring channel 11. The pouring port of the pouring cup 5 is directly aligned with the vertical central column tube 13 connected to the ceramic mold shell 1. Multiple casting cavities 12 are evenly distributed around the vertical central column tube 13, and each casting cavity 12 is connected to the upper side of the vertical central column tube 13 through a pouring channel 11. This design allows multiple castings to be obtained from a single furnace pour, resulting in high production efficiency.

[0042] See Figures 1-5 A slag-free casting method for single-crystal or directionally solidified castings includes the following steps:

[0043] (1) The ceramic mold shell 1 is raised into the first position of the hot chamber 3 by the lifting platform 2 for preheating, and the alloy material is melted by the crucible 16;

[0044] (2) Pour the alloy liquid into the intermediate ladle funnel 6 and let it stand for a set time to allow the inclusions to float to the surface;

[0045] (3) Using the lifting platform 2, the ceramic mold shell 1 continues to rise to the second position of the hot chamber 3. During this process, the top block 8 will push the plug 7 through the plug rod to open the funnel nozzle of the intermediate package funnel 6.

[0046] (4) The alloy liquid flows into the ceramic mold shell 1 through the funnel nozzle to fill the mold. The inclusions floating on the alloy liquid eventually flow down and remain on the liquid surface of the pouring cup 5, without entering the casting cavity 12.

[0047] (5) Then the ceramic mold shell 1 is lowered from the hot chamber 3 to the cold chamber 4 to complete the directional solidification of the alloy liquid.

[0048] Unless otherwise stated, if any of the technical solutions disclosed in this invention specify a numerical range, then the disclosed numerical range is a preferred numerical range. Anyone skilled in the art should understand that the preferred numerical range is merely one among many feasible numerical values ​​that has a more obvious or representative technical effect. Because there are many numerical values, it is impossible to list them all. Therefore, this invention discloses only some numerical values ​​to illustrate the technical solutions of this invention. Furthermore, the numerical values ​​listed above should not constitute a limitation on the scope of protection of this invention.

[0049] Furthermore, if the present invention discloses or relates to mutually fixedly connected components or structural parts, then unless otherwise stated, a fixed connection can be understood as: a detachable fixed connection (e.g., using bolts or screws), or a non-detachable fixed connection (e.g., riveting, welding). Of course, mutually fixed connections can also be replaced by an integral structure (e.g., manufactured using a casting process) (except where it is obviously impossible to use an integral molding process).

[0050] Furthermore, unless otherwise stated, the terms used to indicate positional relationships or shapes in any of the technical solutions disclosed in this invention include states or shapes that are similar to, analogous to, or close to those states or shapes. Any component provided by this invention can be assembled from multiple individual components or can be a single component manufactured using a one-piece molding process.

[0051] The above embodiments are merely illustrative examples to clearly illustrate the present invention and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all embodiments here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A slag-free casting structure for single-crystal or directional solidification castings, comprising a directional solidification furnace and a ceramic mold shell (1), wherein the ceramic mold shell (1) is placed on a lifting platform (2) of the directional solidification furnace, and the directional solidification furnace has a hot chamber (3) and a cold chamber (4), characterized in that: The top of the ceramic mold shell (1) is equipped with a pouring cup (5). The top of the hot chamber (3) is directly above the pouring cup (5) and an intermediate ladle funnel (6) is installed. The funnel nozzle of the intermediate ladle funnel (6) is provided with a plug (7). The ceramic mold shell (1) is equipped with a top block (8) aligned with the plug (7). When the lifting platform (2) drives the ceramic mold shell (1) to rise in the hot chamber (3), the top block (8) can push open the plug (7) so that the alloy liquid in the intermediate ladle funnel (6) flows into the pouring cup (5) through the funnel nozzle. When the lifting platform (2) drives the ceramic mold shell (1) to move downward in the hot chamber (3), the plug (7) can automatically reset to seal the funnel nozzle; Below the plug (7), a plug rod (9) is formed that extends out of the funnel and cooperates with the top block (8). The plug (7) and the funnel are in conical contact, and a leakage gap is formed when they separate. The top block (8) is fixedly installed in the pouring cup (5); The plug (7) is a conical ceramic plug, and the top block (8) is a strip-shaped ceramic block.

2. The slag-free casting structure for single-crystal or directionally solidified castings according to claim 1, characterized in that: The top of the hot chamber (3) is provided with a furnace cover (10) that can be opened and closed and can cover the intermediate ladle funnel (6).

3. The slag-free casting structure for single-crystal or directionally solidified castings according to claim 1, characterized in that: The ceramic mold shell (1) and the pouring cup (5) are integrally formed.

4. The slag-free casting structure for single-crystal or directionally solidified castings according to any one of claims 1-3, characterized in that: The ceramic mold shell (1) has a pouring channel (11) and a casting cavity (12), and the pouring port of the pouring cup (5) is connected to the casting cavity (12) through the pouring channel (11).

5. The slag-free casting structure for single-crystal or directionally solidified castings according to claim 4, characterized in that: The pouring port of the pouring cup (5) is directly aligned with the vertical central column tube (13) that connects to the ceramic mold shell (1). Multiple casting cavities (12) are evenly distributed around the vertical central column tube (13). Each casting cavity (12) is connected to the upper side of the vertical central column tube (13) through a pouring channel (11).

6. A slag-free casting method for single-crystal or directionally solidified castings, employing the slag-free casting structure for single-crystal or directionally solidified castings as described in any one of claims 1-5, characterized in that, Includes the following steps: (1) The ceramic mold shell (1) is raised into the first position of the hot chamber (3) using the lifting platform (2) for preheating, and the alloy material is melted using the crucible; (2) Pour the alloy liquid into the intermediate ladle funnel (6) and let it stand for a set time to allow the inclusions to float to the surface; (3) Using the lifting platform (2) to drive the ceramic mold shell (1) to continue to rise to the second position of the hot chamber (3), during this process, the top block (8) will push the block (7) to open the funnel nozzle of the intermediate package funnel (6); (4) The molten alloy flows into the ceramic mold shell (1) through the funnel nozzle to fill the mold. The inclusions floating on the molten alloy eventually flow down and remain on the liquid surface of the pouring cup (5), without entering the casting cavity (12). (5) Then the ceramic mold shell (1) is lowered from the hot chamber (3) to the cold chamber (4) to complete the directional solidification of the alloy liquid.

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