A connecting structure of a heat-insulating riser and a cast body and a manufacturing method thereof
By using insulating risers made of insulating materials such as aluminum silicate and a multi-layer coating process, the problems of insufficient insulation and dimensional waste in titanium and zirconium alloy castings have been solved. This has enabled efficient feeding and stable connection, reduced costs and processing complexity, and improved casting quality.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XIAN PUMP & VALVE GENERAL FACTORY CO LTD
- Filing Date
- 2026-04-30
- Publication Date
- 2026-06-05
AI Technical Summary
In the casting process of titanium and zirconium alloys, the traditional riser has insufficient heat preservation performance, resulting in excessively fast cooling of the molten metal, poor feeding effect, and excessively large size design, which leads to waste of metal materials and high processing complexity, affecting the quality and cost of castings.
Insulation materials such as aluminum silicate and zirconia hollow microspheres are used, combined with a multi-layer coating process to form a composite structure of insulation risers. Through calcination and vacuum degassing, reliable connection with the main casting body is ensured, and stability is maintained at high temperatures.
It improves thermal insulation performance, reduces riser size and metal waste, increases process yield, simplifies processing steps, reduces manufacturing costs, and improves the internal quality and connection stability of castings.
Smart Images
Figure CN122142243A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of titanium and zirconium alloy casting technology, and in particular to a connection structure between an insulating riser and the main body of a casting and its manufacturing method. Background Technology
[0002] Titanium and zirconium alloys, with their outstanding characteristics such as high specific strength, excellent corrosion resistance, and superior high-temperature mechanical properties, are increasingly widely used in high-end manufacturing fields such as aerospace, shipbuilding, chemical equipment, and medical devices, becoming indispensable key structural materials in these fields. However, titanium and zirconium alloys inherently possess high melting points and strong chemical reactivity. During the casting process, they are highly susceptible to internal defects such as shrinkage cavities and porosity due to uneven solidification, severely affecting the structural integrity and reliability of the castings. As the core structural unit in the casting process that enables sequential solidification and provides feeding molten metal to the casting, the riser's design rationality and performance directly determine the internal quality and production yield of the casting, making it a crucial link in solving casting defects in titanium and zirconium alloys.
[0003] Currently, traditional titanium and zirconium alloy casting risers mostly use graphite materials, or are made from the same material as the mold. However, this approach has significant drawbacks: because the materials used in the risers typically have high thermal conductivity, their heat retention is poor. During the casting process, the molten metal inside the riser cools too quickly, failing to fully utilize its feeding function and significantly reducing its effectiveness.
[0004] To ensure sufficient feeding distance and pressure in castings and compensate for insufficient insulation performance, a conservative design approach of "large size and large allowance" is often adopted in actual design, resulting in riser diameters and heights that typically far exceed theoretical calculations. This unreasonable design directly leads to two serious problems: First, the riser occupies a very high proportion of the molten titanium and zirconium alloy, and since titanium and zirconium alloys are expensive, this results in significant material waste, leading to a generally low yield rate (the ratio of casting weight to total gating weight), significantly increasing manufacturing costs. Second, after solidification, excessively large risers require considerable time for cutting, grinding, and other removal operations, resulting in large machining allowances, increased complexity of machining processes, further extended production cycles, and further increased overall manufacturing costs.
[0005] In summary, in the field of titanium and zirconium alloy casting, how to reduce riser size, improve process yield, simplify subsequent processing steps, and achieve reliable connection with molds of different materials while ensuring excellent heat preservation and feeding performance are the technical challenges that urgently need to be solved in the current field of titanium and zirconium alloy casting technology. Summary of the Invention
[0006] This invention provides a method for manufacturing a connection structure between an insulating riser and the main body of a casting, in order to solve the problem of how to reduce the riser size, improve the process yield, simplify subsequent processing steps, and achieve a reliable connection with molds of different materials while ensuring excellent insulation and feeding performance. This is a technical problem that urgently needs to be solved in the current field of titanium and zirconium alloy casting technology.
[0007] This invention discloses a method for manufacturing a connection structure between an insulating riser and the main body of a casting, the method comprising the following steps:
[0008] The structure and dimensions of the insulating riser are determined based on the main body of the casting. The first riser substrate is made of aluminum silicate, zirconia hollow microspheres, alumina hollow microspheres, or pure zirconia insulation cotton. A layer of silica sol is coated on the outer surface of the first riser substrate and dried to obtain the second riser substrate; At least one layer of top dressing slurry is applied to the inner cavity of the second riser substrate. After each layer of the top dressing slurry is applied, yttrium oxide sand is sprinkled on it. After each application, the substrate is dried to obtain the third riser substrate. At least one layer of the surface slurry is coated on the inner cavity of the third riser substrate without sprinkling sand, and the fourth riser substrate is obtained by drying after each coating. At least one layer of backing slurry is applied to the outer surface of the fourth riser substrate. After each layer of backing slurry is applied, backing sand is sprinkled on it. After each application, the substrate is dried to obtain the fifth riser substrate. A layer of the backing slurry is coated onto the outer surface of the fifth riser substrate, sealed, and dried to obtain the sixth riser substrate. The insulation riser is obtained by calcining the sixth riser substrate at 1050℃ or vacuum degassing at 900℃. The heat-insulating riser is fixedly connected to the main body of the casting; The connected insulating riser and the main body of the casting are placed in an electric resistance furnace and preheated at 300-350℃ for 1.5-2 hours; The connection structure between the insulating riser and the main body of the casting is obtained by casting.
[0009] Optionally, the cross-section of the insulating riser is cylindrical or trapezoidal.
[0010] Optionally, the surface layer slurry is a mixture of a surface layer adhesive and yttrium oxide powder.
[0011] Optionally, the backing slurry is a mixture of silica sol, bauxite powder, and mullite powder.
[0012] Optionally, the main body of the casting is a pump body investment casting mold shell or an impeller graphite mold.
[0013] Optionally, when the main body of the casting is a pump body investment casting mold shell, before fixing the insulating riser to the main body of the casting, a layer of surface slurry is brushed onto the area to be connected between the two. After the coating dries, the insulating riser is fixedly connected to the main body of the casting by iron wire.
[0014] Optionally, when the main body of the casting is a graphite impeller, before fixing the insulating riser to the main body of the casting, a special graphite casting coating slurry is sprayed onto the area to be connected. After the coating dries, the insulating riser is fixedly connected to the main body of the casting by wire.
[0015] Optionally, the graphite casting-specific coating slurry is a mixture of zirconium diacetate and yttrium oxide powder.
[0016] The present invention also discloses a connection structure between an insulating riser and the main body of a casting, which is manufactured using the above-described method for manufacturing the connection structure between the insulating riser and the main body of the casting.
[0017] The beneficial effects of the insulation riser and casting body connection structure and its manufacturing method provided by this invention are as follows: The insulation riser and casting body connection structure obtained by the manufacturing method of this invention has significantly improved insulation performance. The riser matrix is made of insulation materials such as aluminum silicate and zirconia hollow microspheres, combined with a multi-layer coating process to form a composite structure, which effectively reduces the thermal conductivity, slows down the cooling rate of the molten metal in the insulation riser, and ensures that the molten metal maintains sufficient fluidity and feeding capacity. This completely solves the problems of insufficient insulation and poor feeding effect of traditional graphite risers. At the same time, the size of the insulation riser is greatly reduced. Due to the improved insulation performance, there is no need to adopt a conservative design of "large size and large allowance". The diameter and height of the insulation riser can be close to the theoretical calculation value, reducing the waste of titanium and zirconium alloy molten metal, significantly improving the process yield, and reducing material costs. Furthermore, it simplifies the subsequent processing steps. After the miniaturized insulation riser solidifies, the cutting and grinding time is greatly reduced, reducing machining allowance and process complexity, shortening the production cycle, and further controlling manufacturing costs. In addition, the entire process of coating, drying, baking / vacuum degassing treatment ensures the stability of the insulation riser structure, improves the reliability of the connection with the main body of the casting, adapts to the working conditions of high-temperature casting of titanium and zirconium alloys, ensures the internal quality of the casting, and reduces defects such as shrinkage cavities and porosity. Attached Figure Description
[0018] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Figure 1 This is a schematic diagram of the physical structure of the heat-insulating riser provided in an embodiment of the present invention; Figure 2 This is a comparison diagram of the defects of the insulating riser provided in the embodiment of the present invention and the riser of the existing process; Figure 3This is one of the schematic diagrams of the connection structure between the heat-insulating riser and the main body of the casting in an embodiment of the present invention; Figure 4 This is the second schematic diagram of the connection structure between the heat-insulating riser and the main body of the casting in an embodiment of the present invention; Figure 5 This is the third schematic diagram of the connection structure between the heat-insulating riser and the main body of the casting in this embodiment of the invention.
[0019] The labels for the attached figures are as follows: 10. Insulating riser; 20. Casting body. Detailed Implementation
[0020] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
[0021] This invention provides a method for manufacturing a connection structure between an insulating riser and the main body of a casting, the method comprising the following steps: S1. Determine the structure and dimensions of the insulation riser 10 based on the main body 20 of the casting.
[0022] S2. The first riser substrate is made of aluminum silicate, zirconia hollow microspheres, alumina hollow microspheres or pure zirconia insulation cotton material.
[0023] S3. A layer of silica sol is coated on the outer surface of the first riser substrate and dried to obtain the second riser substrate.
[0024] S4. Two layers of slurry are applied sequentially to the inner cavity of the second riser substrate. After each layer of slurry is applied, yttrium oxide sand is sprinkled on top. After each application, the substrate is dried to obtain the third riser substrate.
[0025] S5. Two layers of slurry are applied to the cavity of the third riser matrix without sprinkling sand. After each application, the matrix is dried to obtain the fourth riser matrix.
[0026] S6. Two layers of backing slurry are applied to the outer surface of the fourth riser substrate. After each layer of backing slurry is applied, backing sand is sprinkled on it. After each application, the substrate is dried to obtain the fifth riser substrate.
[0027] S7. A layer of backing slurry is coated on the outer surface of the fifth riser substrate, sealed and dried to obtain the sixth riser substrate.
[0028] S8. The sixth riser substrate is calcined at 1050℃ or vacuum degassed at 900℃ to obtain the heat-insulating riser 10.
[0029] S9. Securely connect the insulation riser to the main body of the casting.
[0030] S10. Place the connected insulation riser and the casting body into the resistance furnace and preheat at 300-350℃ for 1.5-2 hours.
[0031] S11. The connection structure between the heat-insulating riser and the main body of the casting is obtained by casting.
[0032] In S10, the temperature inside the resistance furnace can be 300℃, 310℃, 320℃, 330℃, 340℃, or 350℃. The preheating time can be 1.5h, 1.6h, 1.7h, 1.8h, 1.9h, or 2.0h.
[0033] Furthermore, the cross-section of the insulating riser 10 is cylindrical or trapezoidal.
[0034] Among them, the cylindrical or trapezoidal cross-sectional structure of the insulating riser 10 can improve the compatibility between the insulating riser and the main body of the casting and the feeding efficiency, avoiding feeding dead zones caused by unreasonable structure of the insulating riser 10. Specifically, the cylindrical cross-section is easy to process and prepare, reducing the manufacturing cost of the insulating riser 10, while ensuring uniform flow of molten metal; the trapezoidal cross-section can optimize the feeding pressure distribution, ensuring that the feeding molten metal flows accurately to the defect-prone areas of the main body of the casting 20, further improving the feeding effect and reducing internal defects of the main body of the casting 20. At the same time, the two structures can be flexibly adapted to titanium and zirconium alloy castings of different sizes and structures, expanding the applicability of this manufacturing method.
[0035] Furthermore, the surface layer slurry is a mixture of a special surface layer adhesive and yttrium oxide powder.
[0036] The restriction of the surface layer slurry is used to ensure the high-temperature resistance and chemical stability of the insulating riser 10, prevent the insulating riser 10 from reacting with the molten metal and contaminating the casting, and improve the structural stability of the insulating riser 10. Specifically, the addition of yttrium oxide powder can effectively resist the high temperature during the casting process of titanium and zirconium alloys, prevent the inner wall of the insulating riser 10 from melting and falling off, and prevent impurities from entering the molten metal and affecting the purity of the casting. The combination of the surface layer special adhesive and yttrium oxide powder ensures that the surface layer slurry is firmly bonded and not easy to fall off, ensuring the integrity of the inner cavity structure of the insulating riser 10, further optimizing the insulation effect, providing stable structural support for feeding, and preventing the feeding channel from being blocked due to the falling off of the surface layer slurry, ensuring a smooth feeding process.
[0037] Furthermore, the backing slurry is a mixture of silica sol, bauxite powder, and mullite powder.
[0038] The limitation on the backing slurry is used to enhance the structural strength and high-temperature resistance of the insulating riser 10, ensuring that the insulating riser 10 does not deform or break under the high-temperature environment of casting. Specifically, the high-temperature resistance of bauxite powder and mullite powder can further improve the overall insulation performance of the insulating riser 10 and reduce heat loss. The bonding effect of silica sol ensures that the backing sand can be firmly attached to the outer surface of the insulating riser 10, forming a stable outer protective structure, preventing the insulating riser 10 from cracking or falling off during baking, preheating and casting, ensuring the integrity of the insulating riser 10 and the normal function of feeding, while extending the service life of the insulating riser 10 and reducing the scrap rate in the preparation process of the insulating riser 10.
[0039] Furthermore, the main body of the casting 20 is either a pump body investment casting mold shell or an impeller graphite mold.
[0040] Among them, the pump body investment casting mold shell and the impeller graphite mold are key components in the high-end manufacturing of titanium and zirconium alloys. Their structures are complex and their performance requirements are high. Traditional risers cannot meet their feeding needs. The insulating riser 10 produced by this method can precisely adapt to the structural characteristics of these two castings, effectively solving the problem of internal defects during the casting process, improving the structural integrity and reliability of the pump body and impeller, and expanding the application of this technical solution in the high-end manufacturing field, enhancing the practicality and market value of the technology. Of course, this embodiment only provides an example of the casting body 20 being a pump body investment casting mold shell or an impeller graphite mold. The casting body 20 can also be any structure with a horizontal plane contact surface; no specific limitation is made here.
[0041] Furthermore, when the main body 20 of the casting is a pump body investment casting mold shell, before fixing the insulation riser to the main body of the casting, a layer of surface slurry is brushed onto the area to be connected between the two. After the coating dries, the insulation riser and the main body of the casting are fixedly connected by iron wire.
[0042] The surface slurry layer allows the insulating riser to form a strong adhesive layer on the connection surface with the main body of the casting, preventing the molten metal from reacting. It also fills the connection gap and enhances the high-temperature resistance of the connection area, preventing the high-temperature molten metal from overflowing from the connection gap. The wire fixing further strengthens the connection stability, ensuring that the insulating riser 10 remains in a fixed position during preheating and casting, ensuring smooth feeding channels, avoiding feeding failure due to loose connection, thereby reducing internal defects in the casting, improving casting quality, simplifying the connection process, and reducing connection costs.
[0043] Furthermore, when the main body 20 of the casting is a graphite impeller, before fixing the insulation riser to the main body of the casting, a special coating slurry for graphite casting is sprayed onto the area to be connected. After the coating dries, the insulation riser and the main body of the casting are fixedly connected by iron wire.
[0044] Among them, the impeller graphite mold is made of special material, and traditional connection methods are prone to problems such as weak adhesion and detachment at high temperatures. The special coating slurry for graphite casting can be adapted to the surface characteristics of graphite material to form a strong adhesive layer, improve the sealing and stability of the connection area, and at the same time avoid chemical reaction between the impeller graphite mold and the insulation riser 10. The iron wire fixing further ensures the reliability of the connection, prevents the insulation riser 10 from shifting during the casting process, ensures the feeding effect, and adapts to the processing characteristics of the impeller graphite mold, simplifies the connection process, improves production efficiency, and reduces the scrap rate in the connection process.
[0045] Furthermore, the special coating slurry for graphite casting is a mixture of zirconium diacetate and yttrium oxide powder.
[0046] The bonding effect of zirconium diacetate ensures that the coating adheres firmly to the joint surface, fills the joint gap, enhances the sealing performance, and prevents molten metal from overflowing. The high temperature resistance and chemical stability of yttrium oxide powder can resist the high temperature of casting, prevent the coating from deteriorating or falling off during preheating and casting, and prevent the graphite mold from reacting chemically with the riser, ensuring the purity of the casting and the normal function of the riser feeding function. The combination of the two further improves the connection quality between the heat-insulating riser and the main body of the casting, and reduces the scrap rate caused by connection problems.
[0047] This application also discloses a connection structure between an insulating riser and the main body of a casting, which is manufactured using the above-mentioned method for manufacturing the connection structure between the insulating riser and the main body of the casting.
[0048] The insulating riser 10 prepared in this embodiment exhibits excellent thermal insulation performance and good feeding effect, effectively reducing defects such as shrinkage cavities and porosity inside the casting. The insulating riser 10 has reasonable dimensions, minimizes metal waste, achieves high process yield, and has low manufacturing costs. The insulating riser is firmly connected to the casting body and has good compatibility, adapting to casting bodies 20 made of different materials. Subsequent processing steps are simple, and the production cycle is short. Furthermore, the connection structure between the insulating riser and the casting body is structurally stable, high-temperature resistant, and corrosion-resistant, meeting the application requirements of high-end titanium and zirconium alloy manufacturing. It can be widely used in aerospace, shipbuilding, chemical equipment, and medical device fields, possessing high practical value and market prospects.
[0049] Example 1: This embodiment provides a method for manufacturing a titanium alloy pump body casting (the main body 20 of the casting is a pump body investment casting mold shell): The specific steps are as follows: S1. Structural Design: Based on the structural dimensions of the inlet flange of the titanium alloy pump body, a cylindrical insulating riser 10 is selected. The inner diameter of the insulating riser 10 is φ40, and its height is 2.5 times the flange thickness.
[0050] S2. Matrix preparation: A cylindrical first riser matrix is formed by processing aluminum silicate fiber.
[0051] S3. Pre-curing of outer surface: A layer of silica sol is uniformly coated on the outer surface of the aluminum silicate riser (first riser substrate), placed in a drying oven, and dried at 50°C for 12 hours, which is equivalent to drying at room temperature for one day, to obtain the second riser substrate.
[0052] S4. Inner cavity surface sand coating: The first layer of surface slurry is coated on the inner cavity of the obtained second riser substrate, and 80-mesh yttrium oxide sand is evenly sprinkled on it. It is then dried at room temperature for 24 hours; the second layer of surface slurry is then coated on, and 120-mesh yttrium oxide sand is evenly sprinkled on it. It is then dried at room temperature for 24 hours to obtain the third riser substrate.
[0053] S5. Inner cavity surface grouting: Apply a layer of surface grout to the inner cavity of the third riser substrate without sprinkling sand, and dry at room temperature for 24 hours; then apply another layer of surface grout without sprinkling sand, and dry at room temperature for 24 hours to obtain the fourth riser substrate.
[0054] S6. Backing coating on the outer surface: Apply a layer of backing slurry to the outer surface of the fourth riser substrate, sprinkle with 80-mesh fine mullite sand, and dry at room temperature for 24 hours; repeat the above operation once and dry at room temperature for 24 hours to obtain the fifth riser.
[0055] S7. External surface sealing: A layer of backing grout is applied to the outer surface of the fifth riser substrate for sealing. After drying at room temperature for 24 hours, the sixth riser substrate is obtained.
[0056] S8. Vacuum degassing treatment: The obtained sixth riser substrate is placed in a calcining furnace and calcined at 1050℃ for 2 hours. It is then cooled to room temperature with the furnace to obtain the heat-insulating riser 10 for later use.
[0057] S9. Mold Treatment and Connection: Before the dewaxing and baking process, the area connecting the inlet flange and the insulating riser 10 of the pump body investment casting shell mold is opened and ground. After dewaxing the pump body investment casting shell mold, a layer of slurry is evenly applied around the opening with a brush. After drying, the pump body investment casting shell mold is baked. The end face of the insulating riser 10 is tightly attached to the coated area of the pump body investment casting shell mold, sealed and fixed with special refractory putty, and then bound with wire.
[0058] S10. Preheating: Place the connected insulating riser 10 and the pump body investment casting shell into an electric resistance furnace and heat at 350℃ for 2 hours.
[0059] S11. Casting: Place the preheated insulating riser 10 and the pump body investment casting shell mold as a whole in the casting station, and pour in molten titanium alloy. The pouring temperature is controlled at 1720-1750℃. After the casting cools, demold and remove the riser to obtain a dense titanium alloy pump body casting (i.e., the insulating riser and the main casting structure) without shrinkage defects. Refer to... Figure 3 and Figure 4 .
[0060] Reference Figure 1 This is a schematic diagram of the structure of the heat-insulating riser 10 obtained in Example 1. Figure 2 The image shows a comparison of the defects of the insulating riser 10 obtained in Example 1 and the riser of the existing process. It can be clearly seen from the image that the conventional riser of the existing process (left side) has a linear defect that can extend into the casting body and affect the connection between the two.
[0061] Example 2: The manufacturing method of the graphite-molded zirconium alloy impeller (the main body 20 of the casting is graphite-molded) in this embodiment is as follows: S1. Structural Design: Based on the impeller structure, a trapezoidal cross-section insulated riser 10 is selected. The small end face dimension of the insulated riser 10 matches the impeller inlet end dimension, and its height is 0.5 times the impeller height.
[0062] S2. Matrix preparation: The trapezoidal first riser matrix is formed by pressing and sintering zirconia hollow microspheres.
[0063] S3. Pre-curing of outer surface: A layer of silica sol is uniformly coated on the outer surface of the first riser substrate and dried at room temperature (25±5℃) for 24 hours with humidity controlled at 40%-60% to obtain the second riser substrate.
[0064] S4. Coating the inner cavity surface layer with sand: Coating the first layer layer slurry with the inner cavity of the second riser substrate, and evenly sprinkling 80-mesh yttrium oxide sand, drying at room temperature for 24 hours; then coating the second layer layer slurry, and evenly sprinkling 120-mesh yttrium oxide sand, drying at room temperature for 24 hours to obtain the third riser substrate.
[0065] S5. Inner cavity surface grouting: Apply a layer of surface grout to the inner cavity of the third riser substrate without sprinkling sand, and dry at room temperature for 24 hours; then apply another layer of surface grout without sprinkling sand, and dry at room temperature for 24 hours to obtain the fourth riser substrate.
[0066] S6. Backing coating on the outer surface: Apply a layer of backing slurry to the outer surface of the fourth riser substrate, sprinkle with 80-mesh fine mullite sand, and dry at room temperature for 24 hours; repeat the above operation once and dry at room temperature for 24 hours to obtain the fifth riser substrate.
[0067] S7. External surface sealing: Apply a layer of backing grout to the outer surface of the fifth riser substrate for sealing, and dry at room temperature for 24 hours, then seal the sixth riser substrate.
[0068] S8. Calcination: The obtained sixth riser matrix is placed in a vacuum degassing furnace and kept at 900℃ and vacuum degree ≤10Pa for 1.5 hours. It is then cooled to room temperature with the furnace to obtain the heat-insulating riser 10 for use.
[0069] S9. Mold Treatment and Connection: Prepare a pre-made graphite mold for the zirconium alloy impeller, reserving a connection groove for the insulating riser 10, with a size equal to the riser cross-sectional size + 10mm. Before connection, uniformly spray a layer of graphite casting-specific coating slurry (mainly composed of zirconium diacetate and yttrium oxide powder) onto the area where the graphite mold of the zirconium alloy impeller connects to the insulating riser 10. After the coating dries, attach the bottom surface of the riser to the connection groove of the graphite mold of the zirconium alloy impeller, seal and fix it with special refractory putty, and then bind it with wire.
[0070] S10. Preheating: Place the connected insulating riser 10 and the zirconium alloy impeller graphite type into a resistance furnace and heat at 300℃ for 2 hours.
[0071] S11. Casting: Place the preheated insulating riser 10 and the zirconium alloy impeller graphite mold as a whole in the casting station, and pour in molten metal at a temperature controlled at 1920℃. After the casting cools, clean the shell mold and remove the riser to obtain a dense, shrinkage-free graphite mold-cast zirconium alloy impeller casting (i.e., the insulating riser and the main casting structure), refer to... Figure 5 .
[0072] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Those skilled in the art can modify the technical solutions described in the above embodiments, or make equivalent substitutions for some of the technical features; and all such modifications and substitutions should fall within the protection scope of the appended claims of the present invention.
Claims
1. A method for manufacturing a connection structure between an insulating riser and the main body of a casting, characterized in that, This production method Includes the following steps: The structure and dimensions of the insulating riser are determined based on the main body of the casting. The first riser substrate is made of aluminum silicate, zirconia hollow microspheres, alumina hollow microspheres, or pure zirconia insulation cotton. A layer of silica sol is coated on the outer surface of the first riser substrate and dried to obtain the second riser substrate; At least one layer of top dressing slurry is applied to the inner cavity of the second riser substrate. After each layer of the top dressing slurry is applied, yttrium oxide sand is sprinkled on it. After each application, the substrate is dried to obtain the third riser substrate. At least one layer of the surface slurry is coated on the inner cavity of the third riser substrate without sprinkling sand, and the fourth riser substrate is obtained by drying after each coating. At least one layer of backing slurry is applied to the outer surface of the fourth riser substrate. After each layer of backing slurry is applied, backing sand is sprinkled on it. After each application, the substrate is dried to obtain the fifth riser substrate. A layer of the backing slurry is coated onto the outer surface of the fifth riser substrate, sealed, and dried to obtain the sixth riser substrate. The insulation riser is obtained by calcining the sixth riser substrate at 1050℃ or vacuum degassing at 900℃. The heat-insulating riser is fixedly connected to the main body of the casting; The connected insulating riser and the main body of the casting are placed in an electric resistance furnace and preheated at 300-350℃ for 1.5-2 hours; The connection structure between the insulating riser and the main body of the casting is obtained by casting.
2. The method for manufacturing the connection structure between the heat-insulating riser and the casting body according to claim 1, characterized in that, The cross-section of the insulating riser is cylindrical or trapezoidal.
3. The method for manufacturing the connection structure between the heat-insulating riser and the casting body according to claim 1, characterized in that, The surface layer slurry is a mixture of surface layer special adhesive and yttrium oxide powder.
4. The method for manufacturing the connection structure between the heat-insulating riser and the casting body according to claim 1, characterized in that, The backing slurry is a mixture of silica sol, bauxite powder and mullite powder.
5. The method for manufacturing the connection structure between the heat-insulating riser and the casting body according to claim 4, characterized in that, The main body of the casting is either a pump body investment casting mold shell or an impeller graphite mold.
6. The method for manufacturing the connection structure between the heat-insulating riser and the casting body according to claim 5, characterized in that, When the main body of the casting is a pump body investment casting mold shell, before fixing the insulating riser to the main body of the casting, a layer of top dressing slurry is brushed onto the area to be connected. After the coating dries, the insulating riser is fixedly connected to the main body of the casting by iron wire.
7. The method for manufacturing the connection structure between the heat-insulating riser and the main body of the casting according to claim 5, characterized in that, When the main body of the casting is a graphite impeller, before fixing the insulating riser to the main body of the casting, a special coating slurry for graphite casting is sprayed onto the area to be connected. After the coating dries, the insulating riser is fixedly connected to the main body of the casting with iron wire.
8. The method for manufacturing the connection structure between the heat-insulating riser and the casting body according to claim 7, characterized in that, The special coating slurry for graphite casting is a mixture of zirconium diacetate and yttrium oxide powder.
9. A connection structure between an insulating riser and the main body of a casting, characterized in that, It is manufactured using the method for manufacturing the connection structure between the heat-insulating riser and the main body of the casting as described in any one of claims 1 to 8.