Shell making method for investment casting part with narrow slit structure
Through a special shell making method, including multiple soaking, sand spreading and drying operations, and the processing of pouring special slurry into the narrow-slit cavity, the problem of insufficient shell strength of investment casting parts in the narrow-slit structure is solved. Achieve high-quality casting parts production.
Patent Information
- Application Number
- CN202411580701.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-07
- Publication Date
- 2025-02-11
AI Technical Summary
In the prior art, the investment casting parts with narrow-slit structures are insufficient in the shell making process, resulting in high waste rate.
A special shell making method is adopted, including injecting raw wax into the mold to make a wax mold, and configuring the surface layer slurry, transition layer slurry, back layer slurry and characteristic slurry, and through multiple soaking and sand sprinkling And drying operation, pour special slurry into the narrow gap cavity, vibrate and tamp it, and finally dewax and roast it.
It effectively increases the strength of the molded shell, avoids cracking and steel leakage, and does not affect local heat dissipation, providing a reliable guarantee for the production of high-quality casting parts.
Smart Images
Figure CN119407100A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of aeroengines, and in particular to a shell making method for a narrow-slot structure investment casting. Background Art
[0002] The investment casting production process mainly includes four processes: wax pattern, shell making, casting and post-processing. Among them, the shell making process is to make the wax pattern after it is completed, through the three processes of slurry hanging, sanding and drying, and then repeated multiple cycles. Shell making is also a relatively important process that is often overlooked. As the product structure of investment castings tends to be complex and the direct processing cost is high, many products with small gaps appear. The gaps are too small, and the slurry and sand cannot be evenly scraped during the shell making process. Even after 2-3 cycles, the sand cannot enter many products, resulting in hollowness. As a result, the shell strength at this position is insufficient, and steel leakage occurs during casting, which greatly increases the scrap rate. Summary of the invention
[0003] 1. Technical issues to be resolved
[0004] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a shell making method for narrow-slot structure investment castings, which solves the technical problem in the prior art that the shell strength of narrow-slot structure castings is insufficient during the shell making process, resulting in a high scrap rate.
[0005] (II) Technical solution
[0006] In order to achieve the above object, the main technical solutions adopted by the present invention include:
[0007] An embodiment of the present invention provides a shell making method for a narrow-slot structure investment casting, the method comprising:
[0008] Step S1: injecting raw wax into a mold to make a wax mold;
[0009] Step S2: respectively preparing the surface layer slurry, the transition layer slurry, the back layer slurry and the special slurry;
[0010] Step S3: immersing the wax model in the surface slurry, sanding the soaked wax model, and drying the sanded wax model to obtain a first wax model;
[0011] Step S4: immersing the first wax mold in the transition layer slurry, sanding the immersed first wax mold, and drying the sanded first wax mold to obtain a second wax mold;
[0012] Step S5: pouring special slurry into the narrow slit of the second wax model, vibrating and compacting it, and leaving it to air dry to obtain a third wax model;
[0013] Step S6: immersing the third wax mold in the back layer slurry, sanding the immersed third wax mold, and drying the sanded third wax mold to obtain a fourth wax mold;
[0014] Step S7: applying a layer of sealing material on the surface of the fourth wax mold, drying the sealed fourth wax mold, and then performing a dewaxing process to obtain a mold shell;
[0015] Step S8: calcining the shell.
[0016] Furthermore, the special slurry includes:
[0017] Silica sol, zirconium powder, wetting agent, defoaming agent and water.
[0018] Further, in step S3: silica sol, wetting agent and zirconium powder are added to the container in sequence and stirred, and a defoaming agent is added after stirring to obtain a special slurry.
[0019] Further, stirring was carried out in the container for more than 12 hours.
[0020] Furthermore, the viscosity of the special slurry is 41-47 Pa·s.
[0021] Further, in step S5: the ambient temperature is 21-25° C., and the humidity is 40-60% RH.
[0022] Furthermore, step S4 is repeated 1 to 3 times.
[0023] Further, in step S3: silica sol: 2-2.2 kg, zirconium powder: 8.5-9 kg, wetting agent: 3-4 ml, defoaming agent: 2-3 ml, pure water: 20-25 ml.
[0024] (III) Beneficial effects
[0025] The beneficial effects of the present invention are as follows: the present application mentions a shell making method for a narrow-slit structure investment casting part, the method comprising: injecting raw wax into a mold to make a wax mold; respectively configuring a surface layer slurry, a transition layer slurry, a back layer slurry and a special slurry; immersing the wax mold in the surface layer slurry, sanding the immersed wax mold, and drying the sanded wax mold to obtain a first wax mold; immersing the first wax mold in the transition layer slurry, sanding the immersed first wax mold, and drying the sanded first wax mold to obtain a second wax mold; pouring special slurry into the narrow slit cavity of the second wax mold, vibrating and tamping it, and letting it air-dry to obtain a third wax mold; immersing the third wax mold in the back layer slurry, sanding the immersed third wax mold, and drying the sanded third wax mold to obtain a fourth wax mold; applying a layer of sealing slurry material on the surface of the fourth wax mold, drying the sealed fourth wax mold, and then dewaxing it to obtain a shell; and firing the shell. This application effectively solves the problem of narrow-slot structure investment casting shell making process through special material configuration and process steps. It not only increases the shell strength, avoids cracking and steel leakage, but also does not affect local heat dissipation, providing a reliable guarantee for the production of high-quality castings. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 It is a schematic flow chart of a shell making method of a narrow-slot structure investment casting part of the present invention;
[0027] Figure 2 A schematic diagram of a narrow slot at an angle in an embodiment of a shell making method for an investment casting part with a narrow slot structure according to the present invention;
[0028] Figure 3 It is a schematic diagram of a narrow slot at another angle in an embodiment of a shell making method of an investment casting part with a narrow slot structure of the present invention. DETAILED DESCRIPTION
[0029] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation modes in conjunction with the accompanying drawings.
[0030] When an amount, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed separately. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including ranges "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described in this article, unless otherwise stated, the range is intended to include its end values and all integers and fractions within the range.
[0031] In these embodiments, unless otherwise specified, the parts and percentages are all measured by mass. "Parts by mass" refers to the basic unit of measurement representing the mass ratio relationship of multiple components. 1 part can represent any unit mass, such as 1g, 3.527g, etc. If we say that the mass parts of component A are a parts and the mass parts of component B are b parts, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it means that the mass of component A is aK and the mass of component B is bK (K is an arbitrary number, indicating a multiple factor). It should not be misunderstood that, unlike the mass parts, the sum of the mass parts of all components is not limited to 100 parts. "And / or" is used to indicate that one or both of the situations described may occur, for example, A and / or B include (A and B) and (A or B).
[0032] In order to better understand the above technical solution, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.
[0033] refer to Figure 1 In this technical solution, the above method includes the following steps:
[0034] Step S1: injecting raw wax into a mold to make a wax mold.
[0035] Specifically, the raw wax is injected into the mold, and the dimensional accuracy and surface quality of the wax mold are ensured through precise mold design and wax injection process. The wax mold produced will serve as the basis for the subsequent shell making process.
[0036] The wax mold is made by injecting the raw wax into the mold, which provides an accurate shape basis for the subsequent shell making process. The wax mold can be made into various complex shapes according to the design requirements to meet the needs of narrow gap structure castings.
[0037] Step S2: respectively prepare the surface layer slurry, transition layer slurry, back layer slurry and special slurry.
[0038] The surface layer slurry, transition layer slurry, back layer slurry and special slurry are configured separately.
[0039] In this technical solution, surface layer slurry, transition layer slurry, back layer slurry and special slurry are configured respectively, providing suitable materials for shell making at different stages. The surface layer slurry has good adhesion and smoothness, which guarantees the surface quality of the shell. The transition layer slurry plays the role of connecting the surface layer and the back layer, ensuring the integrity and strength of the shell. The back layer slurry mainly provides the strength and stability of the shell. The special slurry is specially used for filling narrow gaps and cavities.
[0040] Step S3: immersing the wax model in the surface layer slurry, sanding the soaked wax model, and drying the sanded wax model to obtain a first wax model.
[0041] In step S3: silica sol: 2-2.2 kg, zirconium powder: 8.5-9 kg, wetting agent: 3-4 ml, defoaming agent: 2-3 ml, pure water: 20-25 ml.
[0042] It should be noted that the wax mold is immersed in the surface slurry so that a layer of slurry is evenly attached to the surface of the wax mold. Sand the soaked wax mold to increase the strength and roughness of the shell. The particle size and distribution of the sand should be uniform to ensure the quality of the shell. The sanded wax mold is dried to obtain the first wax mold. Exemplarily, in this step, silica sol (2.2Kg), wetting agent (4ml) and zirconium powder (9kg) are added to the container in sequence and stirred for more than 12 hours to ensure that the various ingredients are fully mixed. After stirring, a defoamer (3ml) is added to obtain a special slurry.
[0043] In this technical solution, the wax model is immersed in the surface slurry to make the slurry evenly adhere to the surface of the wax model, which can provide good surface finish and initial strength for the shell. Sanding the soaked wax model increases the roughness and strength of the shell, which helps the adhesion of subsequent layers of slurry. Drying obtains the first wax model. Controlling the drying conditions can avoid defects such as cracks and ensure the quality of the shell.
[0044] Exemplarily, the special slurry consists of silica sol, zirconium powder, a wetting agent, a defoaming agent and water.
[0045] In this technical solution, during the preparation of the special slurry, silica sol, wetting agent and zirconium powder are added in sequence and stirred for more than 12 hours, so that the various components can be fully mixed and the special slurry has good performance. Silica sol is used as a base material to provide bonding; the wetting agent improves the wettability between the components to ensure that materials such as zirconium powder can be evenly dispersed; the zirconium powder increases the strength and high temperature resistance of the shell; the defoamer eliminates bubbles generated during the stirring process and improves the quality of the shell.
[0046] Step S4: immersing the first wax mold in the transition layer slurry, sanding the immersed first wax mold, and drying the sanded first wax mold to obtain the second wax mold.
[0047] Immerse the first wax model in the transition layer slurry, and also ensure that the slurry is evenly attached. Sand the soaked first wax model. Dry the sanded first wax model to obtain the second wax model. This step can be repeated 1 to 3 times as needed. The transition layer slurry plays a good role in connecting the surface layer and the back layer, making the overall performance of the shell more stable.
[0048] Step S5: Pour the special slurry into the narrow slit cavity of the third wax model, vibrate and tamp it, and let it air-dry to obtain the third wax model.
[0049] refer to Figure 2 and Figure 3 , Figure 2 and Figure 3 All of them show a narrow slit structure in the embodiment of the present application. For example, a special slurry is poured into the narrow slit cavity of the third wax mold, and vibrated and compacted to ensure that the slurry fully fills the narrow slit and avoids the appearance of voids or bubbles. Place it in an ambient temperature of 21-25°C and a humidity of 40-60% RH to air dry. This environmental condition is conducive to the curing and stabilization of the special slurry, ensuring a good filling effect. Step S6: Immerse the third wax mold in the back layer slurry, sand the soaked third wax mold, and dry the sanded third wax mold to obtain the fourth wax mold.
[0050] The third wax mold is immersed in the backing slurry for soaking, sanding and drying. The backing slurry provides the main strength and stability for the shell, ensuring that the shell can withstand the impact of high-temperature molten metal during the casting process.
[0051] Step S7: applying a layer of sealing material on the surface of the fourth wax mold, drying the sealed fourth wax mold, and then performing a dewaxing process to obtain a mold shell.
[0052] A layer of sealing material is applied on the surface of the fourth wax mold to further enhance the sealing and strength of the mold shell and prevent the leakage of molten metal during the casting process. The fourth wax mold after sealing is dried to ensure that the sealing material is fully solidified.
[0053] Step S8: calcining the shell.
[0054] The shell is roasted to remove residual moisture and organic matter, improve the strength and refractoriness of the shell, and prepare for the subsequent casting process. The shell after roasting is stronger and can withstand the high temperature casting process, providing a guarantee for obtaining high-quality castings.
[0055] The present application mentions a shell making method for narrow-slot structure investment castings, which is to make a wax mold by injecting raw wax into a mold; respectively configuring a surface layer slurry, a transition layer slurry, a back layer slurry and a special slurry; and then sequentially performing soaking, sanding and drying operations on the wax mold, and in specific steps also including pouring a special slurry into the narrow slit cavity, applying a sealing slurry material, drying and dewaxing treatment, and finally baking the obtained shell. By configuring a special shell making material, after the shell is prepared for 3 layers and dried, the small gaps are treated with this material separately, which not only increases the shell strength and ensures that the shell will not crack and leak steel, but also does not affect the heat dissipation of the local shell, further making the subsequent shell cleaning simple.
[0056] In the description of the present invention, each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description.
[0057] In the description of the present invention, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically limited. Moreover, the term "includes", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not clearly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements limited by the sentence "comprising one..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements.
[0058] In the present invention, unless otherwise clearly specified and limited, when a first feature is “on” or “below” a second feature, it may be that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, when a first feature is “above”, “above” or “above” a second feature, it may be that the first feature is directly above or obliquely above the second feature, or it may simply mean that the first feature is higher in level than the second feature. When a first feature is “below”, “below” or “below” a second feature, it may be that the first feature is directly below or obliquely below the second feature, or it may simply mean that the first feature is lower in level than the second feature.
[0059] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "embodiment", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.
[0060] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may alter, modify, replace and modify the above embodiments within the scope of the present invention.
Claims
1. A shell making method for narrow-slot investment castings, characterized in that: The method comprises: Step S1: injecting raw wax into a mold to make a wax mold; Step S2: respectively preparing the surface layer slurry, the transition layer slurry, the back layer slurry and the special slurry; Step S3: immersing the wax model in the surface slurry, sanding the wax model after immersion, and drying the sanded wax model to obtain a first wax model; Step S4: immersing the first wax mold in transition layer slurry, sanding the immersed first wax mold, and drying the sanded first wax mold to obtain a second wax mold; Step S5: pouring special slurry into the narrow slit of the second wax model, vibrating and compacting it, and air-drying it to obtain a third wax model; Step S6: immersing the third wax mold in the back layer slurry, sanding the immersed third wax mold, and drying the sanded third wax mold to obtain a fourth wax mold; Step S7: applying a layer of sealing material on the surface of the fourth wax mold, drying the sealed fourth wax mold, and then performing a dewaxing process to obtain a mold shell; Step S8: calcining the shell.
2. The shell making method of a narrow-slot structure investment casting according to claim 1, characterized in that: The special slurry includes: Silica sol, zirconium powder, wetting agent, defoaming agent and water.
3. The shell making method of a narrow-slot structure investment casting according to claim 1, characterized in that: In step S3: silica sol, wetting agent and zirconium powder are added to the container in sequence and stirred, and a defoaming agent is added after stirring to obtain a special slurry.
4. The shell making method of a narrow-slot structure investment casting according to claim 3, characterized in that: Stir in the vessel for more than 12 hours.
5. The shell making method of a narrow-slot structure investment casting according to claim 1, characterized in that: The viscosity of the special slurry is 41-47 Pa·s.
6. The shell making method of a narrow-slot structure investment casting according to claim 1, characterized in that: In step S5: the ambient temperature is 21-25°C, and the humidity is 40-60%RH.
7. The shell making method of a narrow-slot structure investment casting according to claim 1, characterized in that: The step S4 is repeated 1 to 3 times.
8. The shell making method of a narrow-slot structure investment casting according to claim 2, characterized in that: In step S3: silica sol: 2-2.2 kg, zirconium powder: 8.5-9 kg, wetting agent: 3-4 ml, defoaming agent: 2-3 ml, pure water: 20-25 ml.