A method for preventing the leakage of a high-temperature alloy casting during preparation

Abstract

The application discloses a method for preventing leakage of high-temperature alloy castings in a preparation process, which is characterized by the following steps: a wax mold base is improved, a concave cavity with the same depth is arranged on the upper end face of the wax mold base at the installation position of the crystal growth section of each casting wax mold, the crystal growth section of the casting wax mold is fixed on the flat inner bottom surface of the corresponding concave cavity through wax liquid adhesion, the bottom of the prepared ceramic mold shell is formed with a corresponding boss, the weight of the mold shell is fully pressed on the boss during a ceramic mold shell baking process, the bottom of the boss is less deformed, when the ceramic mold shell is placed on a chilling disc, the contact between the chilling disc and the ceramic mold shell is changed from the original large plane contact to small plane contact, and the two are more closely contacted, so that the molten high-temperature alloy liquid is prevented from flowing out from the gap between the bottom of the ceramic mold shell and the chilling disc.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of investment casting, and particularly relates to a method for preventing leakage of molten high-temperature alloy during preparation of high-temperature alloy castings. BACKGROUND

[0002] During preparation of directional and single-crystal high-temperature alloy castings, the bottom of the ceramic mold shell is a large flat surface, and deformation easily occurs during baking, resulting in unevenness of the bottom of the ceramic mold shell, so that the ceramic mold shell and the chill plate cannot be in close contact, and the molten high-temperature alloy liquid will flow out from the gap between the bottom of the ceramic mold shell and the chill plate, leading to leakage of the molten high-temperature alloy, causing the castings to be scrapped, and causing serious economic losses and damage to the equipment. SUMMARY

[0003] The main purpose of the present application is to provide a method for preventing leakage of molten high-temperature alloy during preparation of high-temperature alloy castings, which improves the wax mold base plate so that the bottom of the prepared ceramic mold shell can be closely attached to the chill plate, and the molten high-temperature alloy liquid will not flow out from the gap between the bottom of the ceramic mold shell and the chill plate.

[0004] To this end, the method for preventing leakage of molten high-temperature alloy during preparation of high-temperature alloy castings provided by the present application improves the wax mold base plate, sets a recess with the same depth at each wax mold crystal nucleation segment installation position on the upper end surface of the wax mold base plate, and fixes the wax mold crystal nucleation segment in the recess by wax bonding, so that the slurry sand on the outer side of the base plate is wiped off during slurry spraying and sanding, and the bottom of the base plate of the prepared ceramic mold shell forms a corresponding boss. During the baking process of the ceramic mold shell, the weight of the mold shell is fully pressed on the boss, the bottom of the boss deforms little, and when the ceramic mold shell is placed on the chill plate, the contact between the chill plate and the ceramic mold shell changes from large plane contact to small plane contact, and the two are more closely attached, thereby achieving the purpose of preventing the molten high-temperature alloy liquid from flowing out from the gap between the bottom of the ceramic mold shell and the chill plate.

[0005] Specifically, an annular retaining ring is further arranged at the edge of the upper end surface of the wax mold base plate, and a corresponding ceramic retaining wall is formed on the upper surface of the base plate of the ceramic mold shell.

[0006] Specifically, the axis of the annular retaining ring coincides with the axis of the wax mold base plate.

[0007] Specifically, the depth of the recess is 1mm-10mm.

[0008] Specifically, the height of the ceramic retaining wall is 10mm-30mm.

[0009] Specifically, the plurality of recesses are arranged in a circumferential array, and the distribution axis coincides with the axis of the wax mold base plate.

[0010] Specifically, a flat inner bottom surface of each of the recessed cavities is provided with a butt joint boss or butt joint pit matching the wax mold crystal segment.

[0011] Specifically, during smelting and pouring, the molten metal enters the inner cavity of the ceramic mold shell through the pouring cup and the cross runner of the ceramic mold shell.

[0012] Specifically, the recessed cavities are cylindrical.

[0013] Specifically, the castings are single crystal castings or directional castings.

[0014] Compared with the prior art, at least one embodiment of the present application has the following beneficial effects: a recessed cavity with the same depth is arranged at each wax mold crystal segment installation position on the upper end surface of the wax mold base, so that the bottom of the prepared ceramic mold shell base forms a corresponding boss, the weight of the mold shell is fully pressed on the boss during the baking process of the ceramic mold shell, the bottom of the boss in contact with the chill plate deforms less, and when the ceramic mold shell is placed on the chill plate, the contact between the chill plate and the ceramic mold shell is changed from the original large plane contact to small plane contact, and the contact between the two is also more closely fitted, thereby achieving the purpose of preventing the molten high-temperature alloy liquid from flowing out from the joint between the bottom of the ceramic mold shell and the chill plate. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative effort.

[0016] Figure 1 is a top view schematic diagram of the wax mold base provided by the embodiments of the present application;

[0017] Figure 2 is Figure 1 is a cross-sectional view schematic diagram of A-A in

[0018] Figure 3 is a schematic diagram of the outer side of the ceramic mold shell base with the slurry not wiped off provided by the embodiments of the present application;

[0019] Figure 4 is a schematic diagram of the baking of the ceramic mold shell provided by the embodiments of the present application;

[0020] Figure 5 is a schematic diagram of the ceramic mold shell placed on the chill plate provided by the embodiments of the present application;

[0021] Figure 6 is another schematic diagram of the structure of the wax mold base provided by the embodiments of the present application;

[0022] Wherein: 1, wax mold base plate; 2, wax mold crystal initiation section of casting; 3, concave cavity; 4, ceramic mold shell; 5, boss; 6, chilling disc; 7, annular retaining ring; 8, ceramic retaining wall; 9, butt boss; 10, support plate; 11, baking furnace. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0024] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0025] In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0026] Referring to Figures 1-3 A method for preventing leakage of high-temperature alloy castings during preparation, by improving the wax mold base plate 1, a concave cavity 3 with the same depth is arranged on the upper end face of the wax mold base plate 1 corresponding to the installation position of each wax mold crystal initiation section 2 of the casting, and the wax mold crystal initiation section 2 of the casting is fixed on the flat inner bottom surface of the corresponding concave cavity 3 by wax bonding, and during the slurry and sand spraying process, the slurry and sand on the outside of the base plate is wiped off, so that the bottom of the prepared ceramic mold shell 4 forms a corresponding boss 5.

[0027] Referring to Figure 4In the present embodiment, the ceramic mold shell 4 prepared by using the wax mold base plate 1 is placed on the supporting plate 10 of the baking furnace 11 during the baking process, and the weight of the ceramic mold shell 4 will be fully pressed on the boss 5, so that the bottom of the boss 5 is less deformed during the baking process, the flatness of the bottom of the boss 5 is guaranteed, and the boss 5 can support the entire ceramic mold shell 4, the ceramic mold shell 4 is suspended in the baking furnace 11 and is heated uniformly, and is not prone to thermal deformation.

[0028] Referring to Figure 5 In addition, when the ceramic mold shell 4 is placed on the chill plate 6, the bottom of the boss 5 can be closely attached to the chill plate 6, and only the boss 5 of the ceramic mold shell 4 is in contact with the chill plate 6, and the rest is suspended, the contact between the chill plate 6 and the ceramic mold shell 4 is changed from the original large plane contact to small plane contact, so that the two are more closely attached, and even if the boss 5 is slightly deformed, the bottom end surface of the boss 5 can be quickly ground flat by mechanical means, so that the purpose of preventing the molten high-temperature alloy liquid from flowing out from the gap between the bottom of the ceramic mold shell 4 and the chill plate 6 can be achieved, that is, the purpose of preventing leakage of molten steel can be achieved.

[0029] Referring to Figure 3 and Figure 5 In other embodiments, an annular retaining ring 7 is additionally provided outside the upper end surface edge of the wax mold base plate 1, and the slurry and sand outside the base plate and the retaining ring are wiped off during the slurry spraying and sand pouring process, so that a corresponding ceramic retaining wall 8 is formed on the corresponding position of the upper surface of the base plate of the ceramic mold shell 4 after the shell preparation is completed. Such a design not only allows the ceramic retaining wall 8 to effectively block the outflow of metal liquid when the ceramic mold shell 4 leaks, thereby effectively protecting the equipment, but also allows the ceramic retaining wall 8 to act as a pressing ring to press the outer edge of the base plate of the ceramic mold shell 4 during baking, so that the base plate of the ceramic mold shell 4 is not prone to deformation during baking, and the ceramic mold shell 4 can be further guaranteed to closely attach to the chill plate 6 of the directional solidification furnace. In specific designs, the height of the ceramic retaining wall can be controlled to be 10mm-30mm.

[0030] Referring to Figure 1 and Figure 2 It can be understood that the annular retaining ring 7 is in the shape of a cylinder, the outer peripheral wall of the annular retaining ring 7 is flush with the outer peripheral wall of the wax mold base plate 1, the plurality of cavities 3 are arranged in a circumferential array, and the distribution axis coincides with the axis of the annular retaining ring 7, and the axis of the annular retaining ring 7 coincides with the axis of the wax mold base plate 1. Such a design can effectively guarantee the consistency of the performance of the prepared castings. In addition, it should be noted that the depth of the cavity 3 is preferably controlled to be 1mm-10mm, and a depth that is too high is not conducive to the connection of the wax mold of the casting, and a depth that is too low will also have some adverse effects.

[0031] Referring to Figure 2 and Figure 4In other embodiments, to facilitate the connection between the wax casting pattern and the chassis wax pattern, a docking boss 9 is provided on the bottom surface of each cavity 3. The docking boss 9 is designed to conform to the shape of the wax casting pattern's crystallization section 2. When connecting the wax casting pattern and the chassis wax pattern, the docking boss 9 and the crystallization section 2 are aligned and then firmly bonded using liquid wax. Of course, the docking boss 9 can be replaced with a docking pit. After wax is applied to the bottom of the wax casting pattern's crystallization section 2, the crystallization section 2 is inserted into the docking pit, quickly connecting the wax casting pattern and the chassis wax pattern.

[0032] Among them, the casting is a single crystal casting or a directional casting. When the casting is a single crystal casting, the casting wax mold crystallization section 2 is the crystallization section of the spiral crystal rotator. When the casting is a directional casting, the casting wax mold crystallization section 2 is a columnar crystal crystallization vertical plate.

[0033] See also Figure 6 In other embodiments, in order to facilitate the removal of the slurry and sand on the outside of the chassis during the slurry and sand sprinkling process, the outer wall of the annular retaining ring 7 can be designed as a circumferential surface with the same diameter as the wax mold chassis 1, and the inner wall of the annular retaining ring 7 is an inverted cone surface with a larger upper part and a smaller lower part, and the top diameter of the inverted cone surface is equal to the diameter of the wax mold chassis 1.

[0034] The following will take single crystal casting as an example to explain its specific preparation process including:

[0035] 1. Preparation of wax pattern

[0036] Prepare casting wax molds, chassis wax molds, crystal selector wax molds and pouring system wax molds. The pouring system wax mold includes a center column, a cross runner and a pouring cup. Among them, the wax mold can be pressed by a mold, and can also be obtained by 3D printing.

[0037] 2. Wax model tree

[0038] Combine the casting wax model, chassis wax model, crystal selector wax model and pouring system wax model to obtain a wax tree;

[0039] 3. Preparation of mold shell

[0040] The wax tree is coated with refractory coating layer by layer, and after drying and hardening, it is dewaxed and fired to obtain a ceramic shell;

[0041] 4. Melting and pouring

[0042] The melting and pouring equipment is a vacuum directional solidification furnace. During melting and pouring, the ceramic shell is placed on the chill plate. The poured molten metal enters the inner cavity of the shell through the pouring cup and cross runner of the ceramic shell, and contacts the chill plate through the crystal selector. Freely oriented equiaxed crystals are formed on the surface of the chill plate. Then, under the condition of unidirectional heat flow, the equiaxed crystals are transformed into columnar crystals, and crystals with other orientations are eliminated through competitive growth. Finally, a crystal very close to the orientation is obtained and extends to the entire casting.

[0043] Any of the technical solutions of the present application disclosed above, if it discloses numerical ranges, the disclosed numerical ranges are preferred numerical ranges, any person skilled in the art should understand that the preferred numerical ranges are only the values with more obvious technical effects or representative values among the many implementable values. Because there are too many values to enumerate, the present application discloses some values to illustrate the technical solutions of the present application, and the above-mentioned enumerated values should not constitute a limitation on the protection scope of the present application.

[0044] At the same time, if the above-mentioned present application discloses or involves mutually fixed connecting parts or structural parts, except otherwise stated, the fixed connection can be understood as: detachable fixed connection (for example, using bolt or screw connection), and can also be understood as: non-detachable fixed connection (for example, riveting, welding), of course, the mutually fixed connection can also be replaced by an integral structure (for example, using casting process integral forming manufacturing) (obviously, except for integral forming process).

[0045] In addition, the terms used to represent the position relationship or shape in any of the technical solutions of the present application disclosed above, except otherwise stated, its meaning includes the approximate, similar or close state or shape. Any component provided by the present application can be assembled from a plurality of individual components, or can be a single component manufactured by integral forming process.

[0046] The above examples are only examples for clearly illustrating the present application, and are not limited to the embodiments. Based on the above description, other different forms of changes or variations can also be made by those of ordinary skill in the art. Here, it is neither necessary nor possible to enumerate all the examples. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A method for preventing steel leakage during the production of high-temperature alloy castings, characterized by: By improving the wax mold chassis (1), a cavity (3) with the same depth is provided on the upper end surface of the wax mold chassis (1) corresponding to the installation position of each casting wax mold crystallization section (2), and the casting wax mold crystallization section (2) is fixed to the flat inner bottom surface of the corresponding cavity (3) by wax liquid bonding. During the process of dipping and sanding, the slurry sand on the outer side of the chassis is wiped off, so that a corresponding boss (5) is formed at the bottom of the chassis of the prepared ceramic shell (4). During the firing process of the ceramic shell (4), the weight of the shell is fully pressed on the boss (5), and the bottom of the boss (5) in contact with the quenching plate (6) is slightly deformed. Moreover, when the ceramic shell (4) is placed on the quenching plate (6), the contact between the quenching plate (6) and the ceramic shell (4) is changed from the original large-surface contact to the small-surface contact, and the contact between the two is more closely fitted, thereby achieving the purpose of preventing the molten high-temperature alloy liquid from flowing out from the gap between the bottom of the ceramic shell (4) and the quenching plate (6); An annular retaining ring (7) is also provided on the upper end surface edge of the wax mold chassis (1), and a corresponding ceramic retaining wall (8) is formed on the upper surface of the chassis of the ceramic shell (4); The outer side wall of the annular retaining ring (7) is a circumferential surface having a diameter equal to that of the wax mold base (1), and the inner side wall of the annular retaining ring (7) is an inverted conical surface having a larger upper portion and a smaller lower portion, and the top diameter of the inverted conical surface is equal to the diameter of the wax mold base (1).

2. The method according to claim 1, wherein: The axis of the annular retaining ring (7) coincides with the axis of the wax mold chassis (1).

3. The method according to claim 1, wherein: The height of the ceramic retaining wall (8) is 10 mm to 30 mm.

4. The method according to claim 1, wherein: The depth of the cavity (3) is 1 mm to 10 mm.

5. The method according to any one of claims 1 to 4, characterized in that: The plurality of concave cavities (3) are distributed in a circular array, and the distribution axis coincides with the axis of the wax mold chassis (1).

6. The method according to any one of claims 1 to 4, characterized in that: A docking boss (9) or a docking pit matching the crystallization section (2) of the casting wax mold is provided on the flat inner bottom surface of each cavity (3).

7. The method according to any one of claims 1 to 4, characterized in that: The concave cavity (3) is cylindrical.

8. The method according to any one of claims 1 to 4, characterized in that: The casting is a single crystal casting or a directional casting.

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