A method of cncasting a housing

Abstract

The application relates to the technical field of casting, in particular to a machine case casting method. The machine case casting method comprises the following steps: S10, a mold shell assembly is manufactured according to machine case assembly size parameters and runner assembly size parameters; S20, the mold shell assembly is placed in a sand box in a preset posture; S30, a heat preservation assembly is wrapped around the mold shell assembly, so that a closed heat insulation chamber is formed between an inner cylinder mold shell and an outer cylinder mold shell, and a support plate mold shell is suspended in the heat insulation chamber at a position corresponding to a second side; and S40, metal liquid is poured into a product mold shell through a runner mold shell. Thus, the problems of differential solidification and forming defects of the machine case are solved.

Description

Technical Field

[0001] This application relates to the field of casting technology, and more specifically, to a method for casting a casing. Background Technology

[0002] In high-end equipment fields such as aero-engines, casing castings typically feature thin walls, irregular shapes, and complex internal cavities, making them difficult to form in a single step using ordinary sand casting. Therefore, investment casting is commonly used for their preparation. Existing investment casting methods for casings generally include the following steps: First, a mold is manufactured based on the three-dimensional model of the casing. A corresponding wax model is then pressed from the mold. Next, a gating system is assembled on the wax model, and layers of wax are deposited to form the mold shell. After the shell is deposited, dewaxing is performed to obtain the mold shell. The mold shell is then filled into a sand box, and insulation measures are taken around the shell to control the solidification process. Afterward, the molded shell is placed in a preheating furnace and heated to a predetermined temperature. Once the molten metal melts and reaches the pourable temperature, the mold shell is removed from the preheating furnace, and molten metal is poured into the shell through the gating system. After the molten metal cools and solidifies, the mold shell is removed to obtain the casing casting. In this process, the mold shell must be maintained at a sufficiently high temperature before pouring to ensure the molten metal fills the mold.

[0003] However, existing investment casting processes encounter problems with solidification and forming defects in irregularly shaped, thin-walled casing castings due to the differentiated solidification characteristics of the workpiece. From a heat dissipation perspective, thin-walled areas of the casting have a larger surface area, resulting in a higher contact ratio between the molten metal and the mold shell, and a much faster heat dissipation rate compared to thicker areas. Conversely, thicker areas have a smaller heat dissipation area per unit volume, leading to a slower heat dissipation rate. Regarding molten metal flow and solidification characteristics, thicker areas of the casting exhibit lower flow resistance and better fluidity, while thin-walled areas are significantly constrained by structural morphology, resulting in significantly impaired molten metal flow. Furthermore, based on the nucleation point effect, thin-walled areas have a wider contact area with the mold shell, allowing for a greater number of nucleation points and a significantly faster nucleation and solidification rate. In summary, the core problem with existing technologies is the significant differences in heat dissipation, fluidity, and solidification rate among different structural regions of the casing casting, which easily leads to uneven casting formation. Summary of the Invention

[0004] To address the issues of differential solidification and forming defects in the casing, this application provides a casing casting method, comprising:

[0005] The shell assembly is manufactured according to the size parameters of the casing assembly and the runner assembly; wherein, the casing assembly includes an outer cylinder unit, an inner cylinder unit, and a support plate unit; the outer cylinder unit is coaxial with the inner cylinder unit; the inner cylinder unit is located inside the outer cylinder unit; multiple support plate units are spaced apart around the circumference of the inner cylinder unit; the support plate units are connected between the inner cylinder unit and the outer cylinder unit; the outer cylinder unit has a first end and a second end in the axial direction; the side of the support plate unit closer to the first end is the first side; the side of the support plate unit closer to the second end is the second side; the thickness of the first side is greater than the thickness of the second side; the shell assembly includes a product shell and a runner shell; the product shell includes an outer cylinder shell, an inner cylinder shell, and a support plate shell; the inner cavities of the outer cylinder shell, the inner cylinder shell, and the support plate shell are, in sequence, the molding chambers of the outer cylinder unit, the inner cylinder unit, and the support plate unit; the inner cavity of the runner shell is the molding chamber of the runner assembly;

[0006] The shell assembly is placed in a sand box in a preset posture; wherein, in the preset posture, the outer cylindrical shell and the inner cylindrical shell are both vertically arranged, the support plate shell faces upwards corresponding to the first side, and the support plate shell faces downwards corresponding to the second side.

[0007] The heat insulation component is wrapped around the shell assembly to form a sealed heat insulation chamber between the inner shell and the outer shell, and the support plate shell is suspended in the heat insulation chamber at the position corresponding to the second side;

[0008] Molten metal is poured into the product shell through the gating shell.

[0009] Optionally, the insulation component includes a first sand layer and an insulation cotton layer;

[0010] The step of enclosing the thermal insulation component around the shell component includes:

[0011] The first layer of sand is laid under the shell assembly;

[0012] The insulation layer is laid on top of the product shell.

[0013] Optionally, the insulation component further includes a second sand layer and a third sand layer;

[0014] The method of enclosing the heat insulation component around the shell component further includes:

[0015] The second sand layer is laid on the outer circumference of the outer cylindrical shell;

[0016] The third sand layer is laid on the inner circumference of the inner cylindrical shell.

[0017] Optionally, the insulation component further includes a fourth sand layer;

[0018] The method of enclosing the heat insulation component around the shell component further includes:

[0019] The fourth sand layer is laid on top of the insulation cotton layer.

[0020] Optionally, the fourth sand layer includes a first sand pile and a second sand pile; the particle size of the first sand pile is smaller than that of the second sand pile.

[0021] When the insulation layer is laid, the area where the insulation layer is laid has a first insulation area and a second insulation area. The first insulation area covers the top of the support plate shell, and the second insulation area is located above the cavity between adjacent support plate shells.

[0022] The step of laying the fourth sand layer on top of the insulation layer includes:

[0023] The first sand pile is laid on top of the first insulation area;

[0024] The second sand pile is laid on top of the second insulation area.

[0025] Optionally, the axial dimension of the inner cylindrical shell is smaller than the axial dimension of the outer cylindrical shell; in the preset posture, the top end of the inner cylindrical shell is lower than the top end of the outer cylindrical shell.

[0026] The insulation layer includes a plurality of first insulation sheets and a plurality of second insulation sheets; when the insulation sheets are laid, the first insulation sheets are laid on the top and inner peripheral wall of the outer cylindrical shell, and the first insulation sheets are located above the support plate shell, and the second insulation sheets are laid above the support plate shell and on the top of the inner cylindrical shell.

[0027] Optionally, when the insulation layer is laid, the bottom end of the first insulation sheet extends to the upper surface of the second insulation sheet.

[0028] Optionally, in the preset posture, the end faces of both ends of the outer cylindrical shell are connected to the runner shell, the upper part of the inner peripheral wall of the inner cylindrical shell is connected to the runner shell, and the end face of the bottom of the inner cylindrical shell is connected to the runner shell.

[0029] Optionally, when the insulation layer is laid, the splicing position of two adjacent second insulation sheets is located between two adjacent support shells.

[0030] Optionally, the thickness ratio of the first side to the second side is 1.5 to 2.5.

[0031] To address the issues of differential solidification and molding defects in the casing, this application offers the following advantages:

[0032] By placing the shell assembly in a pre-set orientation within the sand box, with the outer and inner shells vertically aligned axially, and the support plate shell facing upwards on the first side and downwards on the second side, and then surrounding the shell assembly with an insulation component, a sealed, insulated chamber is formed between the inner and outer shells. The support plate shell, corresponding to the second side, is suspended within this chamber, thus blocking convective heat transfer between the chamber and the outside air. This reduces heat loss on the thinner second side of the support plate unit, slowing the rate of heat loss in this thin-walled region and preventing premature cooling of the molten metal before the second side is fully filled. The combined effect of the pre-set orientation and the sealed, insulated chamber ensures sufficient fluidity of the molten metal throughout the filling process, guaranteeing full filling of the shell's interior. This solves the problem of insufficient filling in thin-walled areas, preventing localized defects and weld line cracks in the casting, ultimately improving the reliability of the casing casting. Attached Figure Description

[0033] Figure 1 A schematic diagram of a casing casting method according to one embodiment is shown;

[0034] Figure 2 A front view of a housing assembly according to one embodiment is shown;

[0035] Figure 3 It shows Figure 2 Top view of the medium-sized shell assembly;

[0036] Figure 4 A schematic diagram of a casing assembly according to one embodiment is shown;

[0037] Figure 5 It shows Figure 4 Top view of the casing assembly;

[0038] Figure 6 It shows Figure 5 A cross-sectional view of the casing assembly along AA.

[0039] Reference numerals: 10, casing assembly; 11, outer cylinder unit; 12, inner cylinder unit; 13, support plate unit; 20, shell assembly; 21, product shell; 211, outer cylinder shell; 212, inner cylinder shell; 213, support plate shell; 22, gating shell. Detailed Implementation

[0040] The present disclosure will now be discussed with reference to several exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and thus implement the present disclosure, and are not intended to imply any limitation on the scope of the disclosure.

[0041] As used herein, the term "comprising" and its variations are to be interpreted as open-ended terms meaning "including but not limited to". The term "based on" is to be interpreted as "at least partially based on". The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment". The term "another embodiment" is to be interpreted as "at least one other embodiment". The terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments and are not intended to limit the indicated devices, elements, or components to having a specific orientation or being constructed and operated in a specific orientation. Furthermore, some of the above terms may be used to indicate other meanings besides orientations or positional relationships; for example, the term "upper" may in some cases indicate a dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application according to the specific circumstances. In addition, the terms "installed", "set up", "equipped with", "connected", and "linked" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, elements, or components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. Furthermore, the terms "first," "second," etc., are mainly used to distinguish different devices, elements, or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.

[0042] In this embodiment, as Figure 1 As shown, the casing casting method includes steps S10 to S40. The casing casting method executes steps S10, S20, S30 and S40 sequentially.

[0043] Step S10: Manufacture the shell assembly 20 according to the dimensional parameters of the casing assembly 10 and the gating assembly. The casing assembly 10 includes an outer cylinder unit 11, an inner cylinder unit 12, and a support plate unit 13. (Example...) Figure 4 , Figure 5 and Figure 6 As shown, the outer cylinder unit 11 and the inner cylinder unit 12 are coaxial, with the inner cylinder unit 12 located inside the outer cylinder unit 11. Multiple support plate units 13 are spaced apart around the circumference of the inner cylinder unit 12, and the support plate units 13 connect the inner cylinder unit 12 and the outer cylinder unit 11. The outer cylinder unit 11 has a first end and a second end in the axial direction. The side of the support plate unit 13 closest to the first end is the first side, and the side closest to the second end is the second side. The thickness of the first side is greater than the thickness of the second side to adapt to product manufacturing requirements. Figure 2 and Figure 3 As shown, the shell assembly 20 includes a product shell 21 and a runner shell 22. The product shell 21 includes an outer cylindrical shell 211, an inner cylindrical shell 212, and a support plate shell 213. The inner cavities of the outer cylindrical shell 211, the inner cylindrical shell 212, and the support plate shell 213 are, in sequence, the molding chambers of the outer cylindrical unit 11, the inner cylindrical unit 12, and the support plate unit 13. The inner cavity of the runner shell 22 is the molding chamber of the runner assembly. This allows the cavity of the shell assembly 20 to accurately reproduce the irregular structure of the casing assembly 10, providing a molding basis for subsequent casting.

[0044] In step S20, the shell assembly 20 is placed in the sand box in a preset posture. In the preset posture, the outer cylindrical shell 211 and the inner cylindrical shell 212 are both vertically oriented. The support plate shell 213 faces upwards on the first side and downwards on the second side, thus placing the relatively thinner second side at the bottom. This helps to slow down the heat loss rate of this thin-walled area before pouring in subsequent steps and prevents the molten metal from solidifying before filling the second side.

[0045] In step S30, the insulation component is wrapped around the shell assembly 20, forming a sealed heat-insulating chamber between the inner shell 212 and the outer shell 211. The support shell 213, corresponding to the second side, is suspended in this heat-insulating chamber. Because this heat-insulating chamber is isolated from the outside air, convective heat transfer between the internal cavity of the shell assembly 20 and the outside air is blocked, thereby significantly reducing heat exchange and stabilizing the temperature of the shell assembly 20. Furthermore, the thin-walled region of the support shell 213 near the second side is suspended in the heat-insulating chamber, thus avoiding direct contact with the external environment and physical contact with the insulation component. This avoids the risk of the insulation component dissipating heat from the second side, significantly reducing heat loss in this thin-walled region and helping to ensure the uniformity of the local temperature field.

[0046] In step S40, molten metal is poured into the product mold shell 21 through the gating shell 22. Under the combined effect of the aforementioned preset posture and the sealed heat-insulating chamber, the molten metal can maintain sufficient fluidity throughout the filling process, thereby ensuring that the cavity is fully filled, avoiding defects such as local missing parts and gaps or cracks at the weld joints in the casting, and improving the reliability of the casting process.

[0047] In this embodiment, by placing the shell assembly 20 in a sand box in a preset posture, the outer cylindrical shell 211 and the inner cylindrical shell 212 are arranged vertically along their axes, the support plate shell 213 faces upwards on the first side and downwards on the second side, and then the heat insulation component is wrapped around the shell assembly 20, a sealed heat insulation chamber is formed between the inner cylindrical shell 212 and the outer cylindrical shell 211, and the support plate shell 213 is suspended in the heat insulation chamber on the second side, thereby blocking the convective heat transfer between the heat insulation chamber and the outside air, reducing the heat loss path on the second side where the support plate unit 13 is thinner, slowing down the heat loss rate in this thin-walled area, and preventing the molten metal from cooling prematurely before the second side is filled. By combining the preset posture with the sealed heat-insulating chamber, the molten metal can maintain sufficient fluidity throughout the filling process, ensuring that the inner cavity of the product shell 21 is fully filled. This solves the problem of insufficient filling in thin-walled areas, avoids local defects in the casting and gaps and cracks at the weld joints, and ultimately improves the reliability of the casing casting.

[0048] Furthermore, the insulation component includes a first sand layer and an insulation cotton layer.

[0049] Step S30 includes steps S31 and S32.

[0050] Step S31: Lay the first sand layer under the shell assembly 20. The first sand layer covers the bottom area of ​​the shell assembly 20, forming a closed barrier through the accumulation of sand, which can effectively ensure the sealing performance of the bottom and prevent the heat insulation chamber from communicating with the outside atmosphere through the bottom, thereby blocking the convective heat exchange generated therefrom.

[0051] Step S32: Lay the insulation cotton layer on top of the product shell 21. Because the insulation cotton layer has a low thermal conductivity, it will not carry away a large amount of heat from the shell at the beginning of its laying, thus preventing the temperature of the molten metal from dropping sharply.

[0052] It should be understood that combining the two methods of sand sealing and cotton insulation can ensure that there are no gaps for convection ventilation in the overall insulation layer, and can also avoid excessive local cooling in thin-walled areas due to direct contact with the sand, thereby significantly improving the overall insulation effect and reliability of the shell component 20.

[0053] Furthermore, the insulation component also includes a second sand layer and a third sand layer.

[0054] Step S30 also includes steps S33 and S34.

[0055] Step S33: Lay the second sand layer on the outer circumference of the outer cylindrical shell 211.

[0056] Step S34: Lay the third sand layer on the inner circumference of the inner cylindrical shell 212.

[0057] It should be understood that the second sand layer covers the outer cylindrical shell 211 from the outside, and the third sand layer covers the inner cylindrical shell 212 from the inside, thereby forming a supplementary heat insulation layer on the circumference of the inner cylindrical shell 212 and the outer cylindrical shell 211, further suppressing the heat loss of the shell in the circumference, and making the thermal field of the shell more uniform and stable.

[0058] Furthermore, the insulation component also includes a fourth sand layer.

[0059] Step S30 also includes step S35.

[0060] Step S35: Lay the fourth sand layer on top of the insulation cotton layer, and use the fourth sand layer to compact and cover the insulation cotton layer, thereby pressing and fixing the insulation cotton layer and further isolating it from the outside air, thus improving the insulation effect and reducing heat loss.

[0061] Furthermore, the fourth sand layer includes a first sand pile and a second sand pile, wherein the particle size of the first sand pile is smaller than that of the second sand pile.

[0062] When the insulation layer is laid, the area where the insulation layer is laid has a first insulation area and a second insulation area. The first insulation area covers the top of the support plate shell 213, and the second insulation area is located above the cavity between adjacent support plate shells 213.

[0063] Step S35 includes steps S351 and S352.

[0064] Step S351: Lay the first sand pile with finer particle size and better heat insulation effect on top of the first heat insulation area.

[0065] Step S352: A second sand pile with coarser particle size and relatively weaker thermal insulation performance is laid on top of the second thermal insulation area.

[0066] It should be understood that through steps S351 and S352, a fine sand layer with superior insulation performance can be laid on top of the support plate shell 213, which has the highest insulation requirements, while a coarse sand layer is used above the cavity between adjacent support plate shells 213. The fine sand layer is dense and can effectively seal the top pores, reducing the infiltration of outside air; although the coarse sand layer is relatively loose, it can also block the direct airflow channel above the cavity after covering. The combined effect of the two significantly weakens the airflow path between two adjacent cavities of the circumferentially distributed support plate units 13, greatly reducing air convection within the cavity, thereby further reducing heat loss. In this way, the material is rationally utilized while ensuring the overall insulation effect, and the insulation uniformity and overall performance of the insulation cavity along the circumference are significantly improved.

[0067] Furthermore, the axial dimension of the inner cylindrical shell 212 is smaller than that of the outer cylindrical shell 211, and in a preset posture, the top of the inner cylindrical shell 212 is lower than the top of the outer cylindrical shell 211.

[0068] The insulation layer comprises several first insulation sheets and several second insulation sheets. When fully laid, the first insulation sheets are laid on the top and inner peripheral wall of the outer cylindrical shell 211 and above the support plate shell 213; the second insulation sheets are laid above the support plate shell 213 and on the top of the inner cylindrical shell 212. By using the first and second insulation sheets to cover different areas, the top and inner peripheral wall of the outer cylindrical shell 211, the area above the support plate shell 213, and the top of the inner cylindrical shell 212 are completely covered, achieving comprehensive coverage of the insulation area. This reduces the rate of heat loss and improves the product molding effect.

[0069] Furthermore, with the insulation layer laid out, the bottom end of the first insulation sheet extends to the upper surface of the second insulation sheet. Since the axial dimension of the inner cylindrical shell 212 is smaller than that of the outer cylindrical shell 211, and the top of the inner cylindrical shell 212 is lower than the top of the outer cylindrical shell 211, the first insulation sheet can overlap the upper surface of the second insulation sheet as it is laid downwards, thus ensuring the relative stability between the first and second insulation sheets and preventing relative displacement after laying. Simultaneously, it fills the insulation gap at the junction of the first and second insulation sheets, achieving complete coverage of the insulation area.

[0070] In other embodiments, the second insulating cotton sheet covers a larger area of ​​the support plate shell 213 than the first insulating cotton sheet, and its placement at the bottom allows for a closer fit with the surface of the support plate shell 213. Due to its larger coverage area and bottom location, the second insulating cotton sheet can more fully wrap the contour of the support plate shell 213, effectively reducing the gap between it and the shell assembly 20, preventing localized exposure, thereby enhancing the insulation and sealing of the support plate area and further reducing the risk of heat loss in that area.

[0071] Furthermore, in the preset posture, the end faces of both ends of the outer cylindrical shell 211 are connected to the runner shell 22, the upper part of the inner peripheral wall of the inner cylindrical shell 212 is connected to the runner shell 22, and the end face of the bottom of the inner cylindrical shell 212 is connected to the runner shell 22.

[0072] The outer cylindrical shell 211 employs a casting arrangement at both end faces, which reduces corners in the casting path, allowing for smoother metal flow and improved casting efficiency. The inner cylindrical shell 212's inner circumferential wall connects to the gating shell 22 at its upper part, adapting to its lower axial height and closer proximity to the support plate shell 213, thus meeting the higher insulation requirements of this area. Sufficient space can also be reserved above the inner cylindrical shell 212 to facilitate the complete laying of the insulation layer, thereby enhancing the overall casting effect of the product.

[0073] Furthermore, with the insulation layer laid out, the joint between two adjacent second insulation sheets is located between two adjacent support shells 213. Positioning the joint in the cavity between adjacent support shells 213 ensures that the joint avoids critical insulation areas such as directly above the support shells 213, reducing convection ventilation gaps at the joint and thus improving insulation performance and slowing heat loss.

[0074] Furthermore, the ratio of the thickness of the first side to the thickness of the second side is 1.5 to 2.5. This thickness ratio creates an appropriate thin-wall gradient on the second side of the support plate unit 13 relative to the first side, ensuring both the structural rigidity and molding feasibility of the support plate unit 13, and adapting to the specific specifications of the product, thereby balancing casting quality and process adaptability.

[0075] In this embodiment of the casing casting method, the shell assembly 20 is first manufactured according to the dimensional parameters of the casing assembly 10 and the gating assembly. Then, the shell assembly 20 is placed in a sand box with the first side facing upwards and the second side facing downwards. Next, a first sand layer, an insulation layer, a second sand layer, a third sand layer, a fourth sand layer, and the first and second sand piles are sequentially laid. During the laying of the insulation layer, first and second insulation sheets are used to wrap key areas. Finally, molten metal is poured into the product shell 21 through the gating shell 22. After the molten metal cools and solidifies, the shell and insulation assembly are removed to obtain the casing casting. The entire pouring process is completed under the combined protection of a sealed, insulated chamber and the preset orientation, which helps to obtain a complete casting without incomplete pouring defects.

[0076] Those skilled in the art will understand that the above embodiments are specific examples of implementing this disclosure, and in practical applications, various changes can be made in form and detail without departing from the scope of this disclosure.

Claims

1. A method for casting a casing, characterized in that, The casing casting method includes: The shell assembly is manufactured according to the size parameters of the casing assembly and the runner assembly; wherein, the casing assembly includes an outer cylinder unit, an inner cylinder unit, and a support plate unit; the outer cylinder unit is coaxial with the inner cylinder unit; the inner cylinder unit is located inside the outer cylinder unit; multiple support plate units are spaced apart around the circumference of the inner cylinder unit; the support plate units are connected between the inner cylinder unit and the outer cylinder unit; the outer cylinder unit has a first end and a second end in the axial direction; the side of the support plate unit closer to the first end is the first side; the side of the support plate unit closer to the second end is the second side; the thickness of the first side is greater than the thickness of the second side; the shell assembly includes a product shell and a runner shell; the product shell includes an outer cylinder shell, an inner cylinder shell, and a support plate shell; the inner cavities of the outer cylinder shell, the inner cylinder shell, and the support plate shell are, in sequence, the molding chambers of the outer cylinder unit, the inner cylinder unit, and the support plate unit; the inner cavity of the runner shell is the molding chamber of the runner assembly; The shell assembly is placed in a sand box in a preset posture; wherein, in the preset posture, the outer cylindrical shell and the inner cylindrical shell are both vertically arranged, the support plate shell faces upwards corresponding to the first side, and the support plate shell faces downwards corresponding to the second side. The heat insulation component is wrapped around the shell assembly to form a sealed heat insulation chamber between the inner shell and the outer shell, and the support plate shell is suspended in the heat insulation chamber at the position corresponding to the second side; Molten metal is poured into the product shell through the gating shell.

2. The casing casting method according to claim 1, characterized in that, The thermal insulation component includes a first sand layer and a thermal insulation cotton layer; The step of enclosing the thermal insulation component around the shell component includes: The first layer of sand is laid under the shell assembly; The insulation layer is laid on top of the product shell.

3. The casing casting method according to claim 2, characterized in that, The insulation component also includes a second sand layer and a third sand layer; The method of enclosing the heat insulation component around the shell component further includes: The second sand layer is laid on the outer circumference of the outer cylindrical shell; The third sand layer is laid on the inner circumference of the inner cylindrical shell.

4. The casing casting method according to claim 2, characterized in that, The thermal insulation component also includes a fourth sand layer; The method of enclosing the heat insulation component around the shell component further includes: The fourth sand layer is laid on top of the insulation cotton layer.

5. A casing casting method according to claim 4, characterized in that, The fourth sand layer includes a first sand pile and a second sand pile; the particle size of the first sand pile is smaller than that of the second sand pile. When the insulation layer is laid, the area where the insulation layer is laid has a first insulation area and a second insulation area. The first insulation area covers the top of the support plate shell, and the second insulation area is located above the cavity between adjacent support plate shells. The step of laying the fourth sand layer on top of the insulation layer includes: The first sand pile is laid on top of the first insulation area; The second sand pile is laid on top of the second insulation area.

6. The casing casting method according to claim 2, characterized in that, The axial dimension of the inner cylindrical shell is smaller than that of the outer cylindrical shell; in the preset posture, the top of the inner cylindrical shell is lower than the top of the outer cylindrical shell. The insulation layer includes a plurality of first insulation sheets and a plurality of second insulation sheets; when the insulation sheets are laid, the first insulation sheets are laid on the top and inner peripheral wall of the outer cylindrical shell, and the first insulation sheets are located above the support plate shell, and the second insulation sheets are laid above the support plate shell and on the top of the inner cylindrical shell.

7. A casing casting method according to claim 6, characterized in that, When the insulation layer is laid, the bottom end of the first insulation sheet extends to the upper surface of the second insulation sheet.

8. A casing casting method according to claim 6, characterized in that, In the preset posture, the end faces of both ends of the outer cylindrical shell are connected to the runner shell, and the upper part of the inner peripheral wall of the inner cylindrical shell is connected to the runner shell; the end face of the bottom of the inner cylindrical shell is connected to the runner shell.

9. A casing casting method according to claim 6, characterized in that, When the insulation cotton layer is laid, the splicing position of two adjacent second insulation cotton sheets is located between two adjacent support shells.

10. A casing casting method according to claim 1, characterized in that, The thickness ratio of the first side to the second side is 1.5 to 2.5.

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