A directional or single crystal casting pouring cup induction melting structure and method

Abstract

The present invention discloses an induction melting structure and method for a pouring cup for directional or single crystal castings, designed to effectively prevent slag from flowing into the casting cavity and reduce inclusions in the casting. To this end, the present invention provides an induction melting structure for a pouring cup for directional or single crystal castings, comprising a directional solidification furnace and a ceramic mold. The ceramic mold is placed in the hot chamber of the directional solidification furnace. The top of the hot chamber is provided with a furnace top heater capable of melting the alloy material in the pouring cup at the top of the ceramic mold. The side walls of the hot chamber are provided with furnace side heaters. The pouring port at the bottom of the pouring cup is provided with an alloy plug capable of being melted by the alloy liquid.

Description

Technical Field

[0001] The invention belongs to the technical field of investment casting, and in particular relates to an induction melting structure and method for a pouring cup of a directional or single crystal casting. Background Art

[0002] The existing manufacturing process for directional or single crystal castings generally includes the following steps: pressing a wax mold → assembling the wax mold → preparing a mold shell → melting and pouring to obtain a casting. The alloy material is melted in a dedicated crucible and poured by tilting the crucible. The slag on the top of the alloy liquid first enters the mold shell casting cavity, causing inclusion defects in the casting. Summary of the Invention

[0003] The main purpose of the present invention is to provide a directional or single crystal casting pouring cup induction melting structure and method, which aims to effectively prevent slag from flowing into the casting cavity during tilting crucible casting and reduce inclusions in the casting.

[0004] To this end, on the one hand, the present invention provides an induction melting structure for a directional or single crystal casting pouring cup, comprising a directional solidification furnace and a ceramic mold shell, wherein the ceramic mold shell is placed in the hot chamber of the directional solidification furnace and has a melting pouring cup on the top, and the top of the hot chamber is provided with a furnace top heater capable of melting the alloy material in the melting pouring cup, and a furnace side heater is provided on the side wall of the hot chamber, and the pouring port of the melting pouring cup is provided with an alloy plug capable of being melted by the alloy liquid.

[0005] Specifically, the furnace top heater is arranged directly above the chemical pouring cup.

[0006] Specifically, the ceramic mold shell has a pouring channel and a casting cavity, and the pouring port of the chemical pouring cup is connected to the casting cavity through the pouring channel.

[0007] Specifically, the pouring port of the chemical pouring cup is directly aligned with the vertical center column tube connected to the ceramic mold shell, and multiple casting cavities are evenly distributed around the vertical center column tube, and each casting cavity is connected to the upper end side of the vertical center column tube through a pouring channel.

[0008] Specifically, the furnace top heater and the furnace side heater are both graphite induction heaters.

[0009] Specifically, the top of the hot chamber is further provided with a temperature measuring hole aligned with the chemical pouring cup, and an optical thermometer is installed on the temperature measuring hole.

[0010] Specifically, the ceramic mold is placed on a lifting platform of the directional solidification furnace. Driven by the lifting platform, the ceramic mold can be moved from a hot chamber to a cold chamber of the directional solidification furnace to achieve directional solidification.

[0011] Specifically, the ceramic mold shell and the chemical pouring cup are integrally formed.

[0012] Specifically, the material of the alloy plug is the same as or similar to that of the alloy liquid.

[0013] Specifically, a ceramic ring is embedded in the pouring port of the chemical pouring cup, and the alloy plug is installed in the ceramic ring.

[0014] Another aspect of the present invention provides a method for induction melting of a pouring cup for a directional or single crystal casting, comprising the following steps:

[0015] (1) Place the alloy material in the material pouring cup, first use the alloy plug to seal the pouring mouth of the material pouring cup, then use the lifting platform to lift the ceramic mold shell to the hot chamber of the directional solidification furnace, and make the material pouring cup as close to the furnace top heater as possible;

[0016] (2) Start the side heater to preheat the furnace cavity and ceramic mold shell, start the furnace top heater, and gradually heat and melt the alloy material from top to bottom, and the inclusions continue to float up;

[0017] (3) The alloy liquid is kept warm, the alloy plug is melted, and the alloy liquid leaks from the bottom of the material pouring cup into the casting cavity of the ceramic mold shell, and inclusions are retained on the surface of the residual liquid in the material pouring cup;

[0018] (4) The lifting platform drives the ceramic mold shell down to the cold chamber of the directional solidification furnace for directional solidification.

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

[0020] 1. First, put the alloy material into the melting material pouring cup, and place the mold shell in the hot chamber. Start the furnace side heater to preheat the mold shell, and then start the furnace top heater to melt the alloy material gradually from top to bottom. The slag will float up. When the alloy plug at the bottom of the cup is melted, the alloy liquid will leak down and be injected into the casting cavity. The inclusions will remain on the surface of the residual liquid in the melting material pouring cup, thereby achieving the purpose of eliminating foreign inclusions in the casting.

[0021] 2. It eliminates the need for a dedicated melting crucible and tilting pouring system, greatly simplifying equipment and reducing costs.

[0022] 3. The pouring cup originally used to receive the molten liquid is also used as a melting crucible. After melting, the liquid is automatically poured and filled into the mold, and the process is smooth. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. 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 these drawings without creative work.

[0024] Figure 1 Schematic diagram of the induction melting structure of the pouring cup for directional or single crystal castings provided by an embodiment of the present invention;

[0025] Figure 2 Schematic diagram of a ceramic mold shell according to an embodiment of the present invention being placed in a directional solidification furnace for preheating;

[0026] Figure 3 Schematic diagram of ceramic mold casting according to an embodiment of the present invention;

[0027] Figure 4 Schematic diagram of directional solidification during descending ceramic mold according to an embodiment of the present invention;

[0028] Figure 5 This is another structural schematic diagram of a furnace top heater according to an embodiment of the present invention;

[0029] Figure 6 This is a schematic diagram of directional solidification after pouring of another structure of a furnace top heater according to an embodiment of the present invention;

[0030] Among them: 1. Ceramic mold shell; 2. Hot chamber; 3. Material pouring cup; 4. Furnace top heater; 401. Furnace top induction coil; 402. Furnace top induction graphite; 5. Furnace side heater; 501. Furnace side induction graphite; 502. Furnace side induction coil; 6. Alloy plug; 7. Alloy material; 8. Lifting platform; 9. Pouring channel; 10. Casting cavity; 11. Vertical center column tube; 12. Temperature measuring hole; 13. Optical thermometer; 14. Ceramic ring; 15. Cold chamber; 16. Residual plug; 17. Thermal insulation sheet; 18. Inclusions. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0032] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0033] 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 the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0034] See also Figure 1 A directional or single crystal casting pouring cup induction melting structure includes a directional solidification furnace and a ceramic mold 1. The ceramic mold 1 is placed in the directional solidification furnace's hot chamber 2 and has a molten-material pouring cup 3 on top. The top of the hot chamber 2 is provided with a furnace top heater 4 capable of melting alloy material 7 in the molten-material pouring cup 3. The side walls of the hot chamber 2 are provided with furnace side heaters 5. The pouring port of the molten-material pouring cup 3 is provided with an alloy plug 6 capable of being melted by the alloy liquid. As for the other structures of the directional solidification furnace, they are unchanged and are based on existing technology and will not be described in detail here.

[0035] See also Figures 1-4 When using the above-mentioned pouring cup induction melting structure to cast a single crystal high-temperature alloy, first put the alloy material 7 into the material pouring cup 3, then lift the ceramic mold shell 1 together with the material pouring cup 3 into the hot chamber 2 of the directional solidification furnace, and start the side heater to preheat the mold shell, then start the furnace top heater 4, heat and melt the alloy material 7 (from top to bottom), heat and maintain the temperature, and the inclusion 18 floats up. During the insulation process of the alloy liquid, the alloy plug 6 melts, and the alloy liquid leaks into the casting cavity 10 from the bottom. The inclusion 18 remains on the surface of the residual liquid in the material pouring cup 3, and then the ceramic mold shell 1 descends and enters the cold chamber 15 of the directional solidification furnace for directional solidification.

[0036] In this embodiment, an alloy plug seals the bottom of the melt pouring cup. The alloy melts gradually from top to bottom, causing slag to float upwards and achieve static purification. Once the alloy plug melts, the alloy liquid leaks down and enters the casting cavity, leaving inclusions on the surface of the residual liquid in the melt pouring cup, thereby reducing casting inclusions. This also eliminates the need for a dedicated melting crucible and tilting pouring system, significantly simplifying equipment and reducing costs. The pouring cup, which originally receives the molten metal for pouring, doubles as a melting crucible, allowing for automatic pouring and filling after melting, ensuring a smooth process.

[0037] See also Figure 1 and Figure 4 Specifically, the ceramic mold 1 is placed on the lifting platform 8 of the directional solidification furnace. The ceramic mold 1 can be lifted into the hot chamber 2 by the lifting platform 8 to preheat the mold 1 and melt and pour the alloy 7. Then, the poured mold 1 is lowered from the hot chamber 2 into the cold chamber 15 for directional solidification.

[0038] like Figures 1-4 As shown, in this embodiment, when pouring the alloy, the alloy material 7 is loaded into the chemical material pouring cup 3, and the pouring port of the chemical material pouring cup 3 is sealed with the alloy plug 6, and then the ceramic mold shell 1 is raised to the hot chamber 2 of the directional solidification furnace by the lifting platform 8, and the chemical material pouring cup 3 is made as close to the furnace top heater 4 as possible; the furnace side heater 5 is started to preheat the ceramic mold shell 1, and then the furnace top heater 4 is started, so that the alloy material 7 is gradually melted from top to bottom to form an alloy liquid molten pool, in which slag inclusions continuously float up, and when the alloy plug 6 at the bottom of the chemical material pouring cup 3 is melted, the alloy liquid leaks down and is injected into the casting cavity 10, and the inclusions will remain on the surface of the residual liquid in the chemical material pouring cup 3, and then the lifting platform 8 drives the ceramic mold shell 1 down to the cold chamber 15 of the directional solidification furnace, and the alloy liquid in the ceramic mold shell 1 is directional solidified to become a casting.

[0039] It should be explained that, in order to improve the heating efficiency, the furnace top heater 4 is arranged just above the material pouring cup 3 , and the furnace top heater 4 is aligned with the cup mouth of the material pouring cup 3 to heat the alloy material 7 .

[0040] See also Figure 1 and Figure 3 Specifically, the ceramic mold shell 1 has a pouring channel 9 and a casting cavity 10. The pouring port of the chemical pouring cup 3 is connected to the casting cavity 10 through the pouring channel 9. The pouring port of the chemical pouring cup 3 is directly aligned with the vertical center column tube 11 connected to the ceramic mold shell 1. Multiple casting cavities 10 are evenly distributed around the vertical center column tube 11. Each casting cavity 10 is connected to the upper end side of the vertical center column tube 11 through a pouring channel 9. This design allows the residual plug 16 that is not completely melted to directly enter the vertical center column tube 11 instead of entering the casting cavity 10, thereby causing other casting defects.

[0041] It is understood that in order to effectively prevent the alloy plug 6 from affecting the alloy liquid composition, the material of the alloy plug 6 is the same as the cast alloy liquid. Of course, the material of the alloy plug 6 can also be a pure metal with the same composition as the casting matrix, such as pure nickel for nickel-based high-temperature alloys.

[0042] See also Figure 1 Specifically, in the actual design, both the furnace top heater 4 and the furnace side heater 5 adopt graphite induction heaters, which are inductively heated by energized induction coils arranged outside the hot chamber. This design allows the energized elements (induction coils) to be arranged outside the hot chamber, effectively avoiding the impact of high temperature on the service life of the energized elements.

[0043] See also Figure 1 and Figure 4 The furnace side induction graphite 501 of the furnace side heater 5 is arranged inside the hot chamber 2 and surrounds the ceramic mold shell 1. The furnace side induction coil 502 surrounds the outside of the hot chamber 2. The furnace top induction coil 401 of the furnace top heater 4 is arranged outside the top of the hot chamber 2. There are two arrangements of the furnace top induction graphite 402:

[0044] See also Figure 2 and Figure 4 One of the arrangements is that the induction graphite 402 is arranged in the cup mouth of the material pouring cup 3, and can move up and down synchronously with the material pouring cup 3. When the mold shell is installed, the alloy material 7 is placed in the pouring cup, and the induction graphite 402 is placed on the top of the cup. The induction graphite 402 maintains a certain distance from the alloy material 7. The mold shell rises to the highest point, so that the induction graphite 402 on the top of the cup is close to the furnace top, and then the induction coil on the top of the hot chamber 2 is used to realize induction heating of the induction graphite 402. As the mold shell continues to descend, the distance between the induction coil and the induction graphite 402 continues to increase, and the induction graphite 402 is out of the induction range and will automatically stop heating, that is, full heating cannot be achieved; in order to prevent the heat of the induction graphite 402 from being lost from the upper surface, an insulation sheet 17 is also covered on the cup mouth of the material pouring cup 3 above the induction graphite 402, and the insulation sheet 17 can be made of thermal insulation felt.

[0045] See also Figure 5 and Figure 6 Another arrangement is that the induction graphite 402 is directly fixed in the top of the hot chamber 2 and does not move up and down with the material pouring cup 3. The advantage of this arrangement is that the induction coil 401 and the induction graphite 402 are closer, the heating efficiency is higher, and the positions of the two remain unchanged. The induction graphite 402 is induced throughout the whole process, which can achieve full heating and maintain the melt temperature and temperature gradient.

[0046] See also Figure 1It can be understood that, in order to facilitate the temperature measurement of the alloy liquid in the crucible, a temperature measuring hole 12 is provided on the top of the hot chamber 2, which is aligned with the pouring cup 3. An optical thermometer 13 is installed on the temperature measuring hole 12. The optical thermometer 13 is used to measure the temperature of the alloy material 7 in the crucible, and the heating power is adjusted to control the heating rate and the final liquid temperature (filling temperature).

[0047] In some embodiments, in order to reduce production costs, the ceramic mold shell 1 and the chemical pouring cup 3 are integrally formed, that is, by preparing a pouring channel wax mold, a casting cavity wax mold and a pouring cup wax mold, and assembling the molds, the ceramic mold shell 1 is obtained by shell making, and the chemical pouring cup 3 is used as an intermediate package and is made with the shell. It is disposable and will not introduce impurities due to repeated use.

[0048] See also Figure 1 It can be understood that in order to prevent the heat from being quickly transferred to the alloy plug 6 of the pouring gate during the preheating process of the mold shell, causing the alloy plug 6 to melt prematurely, a ceramic ring 14 with relatively poor heat transfer performance is embedded in the pouring gate, and the alloy plug 6 is directly installed in the ceramic ring 14.

[0049] Specifically, the pouring gate can be designed to be conical, the ceramic ring 14 is matched and installed in the conical pouring gate, and the alloy plug 6 is matched and installed in the conical inner cavity of the ceramic ring 14. With this design, the alloy plug 6 and the ceramic ring 14 are easy to install and the plugging is tight.

[0050] Unless otherwise stated, for any of the technical solutions disclosed in the present invention, if a numerical range is disclosed, the disclosed numerical range is a preferred numerical range. Any person skilled in the art should understand that the preferred numerical range is merely a numerical range that is representative or has a more obvious technical effect among many feasible numerical values. Due to the large number of numerical values, it is impossible to enumerate them exhaustively. Therefore, the present invention discloses some numerical values ​​to illustrate the technical solutions of the present invention. Moreover, the numerical values ​​listed above should not be construed as limiting the scope of protection of the present invention.

[0051] At the same time, if the above-mentioned invention discloses or involves components or structural parts that are fixedly connected to each other, then, unless otherwise stated, the fixed connection can be understood as: a detachable fixed connection (for example, using bolts or screws to connect), and can also be understood as: a non-detachable fixed connection (for example, riveting, welding). Of course, the mutual fixed connection can also be replaced by an integrated structure (for example, manufactured by a casting process) (except where it is obviously impossible to use an integrated forming process).

[0052] In addition, unless otherwise stated, terms used in any of the technical solutions disclosed herein to represent positional relationships or shapes include states or shapes that are similar, analogous, or approximate. Any component provided by the present invention may be assembled from multiple separate components or may be a single component manufactured using an integral molding process.

[0053] The above embodiments are merely examples to clearly illustrate the present invention and are not intended to limit its implementation. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to provide an exhaustive list of all embodiments. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. An induction melting structure for a pouring cup of a directional or single crystal casting, comprising a directional solidification furnace and a ceramic mold shell (1), characterized in that: The ceramic mold shell (1) is placed in the hot chamber (2) of the directional solidification furnace and is provided with a material pouring cup (3) on the top. The top of the hot chamber (2) is provided with a furnace top heater (4) capable of melting the alloy material (7) in the material pouring cup (3). The side wall of the hot chamber (2) is provided with a furnace side heater (5). The pouring port of the material pouring cup (3) is provided with an alloy plug (6) capable of being melted by the alloy liquid. The ceramic mold shell (1) has a pouring channel (9) and a casting cavity (10), and the pouring port of the chemical pouring cup (3) is connected to the casting cavity (10) through the pouring channel (9); The pouring port of the chemical pouring cup (3) is directly aligned with the vertical center column tube (11) connected to the ceramic mold shell (1), and a plurality of the casting cavities (10) are evenly distributed around the vertical center column tube (11), and each of the casting cavities (10) is connected to the upper end side of the vertical center column tube (11) through one of the pouring channels (9); A ceramic ring (14) is embedded in the pouring port of the chemical pouring cup (3), and the alloy plug (6) is installed in the ceramic ring (14).

2. The directional or single crystal casting pouring cup induction melting structure according to claim 1, characterized in that: The furnace top heater (4) is arranged directly above the chemical pouring cup (3).

3. The directional or single crystal casting pouring cup induction melting structure according to claim 1, characterized in that: The furnace top heater (4) and the furnace side heater (5) are both graphite induction heaters.

4. The directional or single crystal casting pouring cup induction melting structure according to claim 1, characterized in that: The top of the hot chamber (2) is also provided with a temperature measuring hole (12) aligned with the chemical pouring cup (3), and an optical thermometer (13) is installed on the temperature measuring hole (12).

5. The directional or single crystal casting pouring cup induction melting structure according to claim 1, characterized in that: The material of the alloy plug (6) is the same as or similar to that of the alloy liquid.

6. The directional or single crystal casting pouring cup induction pouring structure according to any one of claims 1 to 5, characterized in that: The ceramic mold shell (1) is placed on the lifting platform (8) of the directional solidification furnace, and the ceramic mold shell (1) can be lowered from the hot chamber (2) of the directional solidification furnace to the cold chamber (15) driven by the lifting platform (8).

7. A method for induction melting of a pouring cup for a directional or single crystal casting, using the induction melting structure for a pouring cup for a directional or single crystal casting according to any one of claims 1 to 6, characterized in that: The steps include: (1) placing alloy material (7) in the material pouring cup (3), and sealing the pouring port of the material pouring cup (3) with an alloy plug (6), and then using a lifting platform (8) to lift the ceramic mold shell (1) into the hot chamber (2) of the directional solidification furnace, and making the material pouring cup (3) as close as possible to the furnace top heater (4); (2) Start the side heater to preheat the ceramic mold shell (1), start the furnace top heater (4) to heat the alloy material (7), and the alloy material (7) is gradually heated and melted from top to bottom, and inclusions continuously float up; (3) The alloy liquid is kept warm, the alloy plug (6) melts, and the alloy liquid leaks from the bottom of the material pouring cup (3) into the casting cavity (10) of the ceramic mold shell (1), and inclusions are retained on the upper surface of the residual liquid in the material pouring cup (3); (4) The lifting platform (8) drives the ceramic mold shell (1) down to the cold chamber (15) of the directional solidification furnace for directional solidification.

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