A single crystal blade without striation crystal defects and a preparation method and application thereof
Single-crystal blades without stripe crystal defects were prepared by 3D printing and an improved sandblasting process, which solved the problem of stripe crystal defects, improved the yield rate and reduced costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SUZHOU GAOJING NEW MATERIAL TECH CO LTD
- Filing Date
- 2023-12-27
- Publication Date
- 2026-07-31
AI Technical Summary
Existing technologies are insufficient to effectively suppress striation defects in single-crystal blades, resulting in low yield and high production costs.
A resin model was prepared by 3D printing. Combined with paraffin coating and an improved sandblasting process, white corundum sand of different particle sizes was used for sandblasting to prepare single-crystal blades without striation defects.
It improved the production qualification rate of single crystal blades, reduced production costs, enhanced the strength of wax molds, and avoided surface defects caused by sand and gravel intrusion.
Smart Images
Figure CN117773004B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of single-crystal blade manufacturing technology, and in particular to a single-crystal blade without striation defects, its preparation method, and its application. Background Technology
[0002] Single-crystal high-temperature alloy blades are key components of aero-engines and ground-based heavy-duty gas turbines. With the continuous development of aerospace and gas turbine technologies, blade structures are becoming increasingly complex, blade sizes are increasing, and the number of alloying elements in blades is also increasing. This leads to a more complex growth environment for dendrites during the directional solidification process of blades, resulting in a continuous increase in the tendency of metallurgical defects to form in single-crystal blades. Consequently, the yield rate of single-crystal blades has been greatly reduced, and the difficulty and cost of production and manufacturing have increased dramatically.
[0003] Currently, there are few measures to control the formation of defects in single-crystal blades, especially the striation crystals on the blade body, for which there is still no good solution. Therefore, how to effectively suppress the formation of striation crystals and improve the yield of single-crystal blades has become a technical problem that urgently needs to be solved in this field. Summary of the Invention
[0004] The purpose of this invention is to provide a single-crystal blade without stripe crystal defects, its preparation method, and its application. The preparation method provided by this invention can eliminate stripe crystal defects in single-crystal blades, improve the production qualification rate of single-crystal blades, and reduce production costs.
[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:
[0006] This invention provides a method for preparing a single-crystal blade without striation defects, comprising the following steps:
[0007] (1) Import the model into a 3D printer for 3D printing to obtain a resin model;
[0008] (2) Coat the resin model obtained in step (1) with paraffin wax to obtain a wax model;
[0009] (3) The wax model obtained in step (2) is used to make a shell to obtain a blade mold shell;
[0010] (4) Cast and directional solidify the blade mold shell obtained in step (3) to obtain a single crystal blade without stripe crystal defects;
[0011] The shell-making process in step (3) includes 9 coats of slurry and 8 sand rinsings; the coats of slurry and sand rinsings are performed alternately; the first sand rinsing includes a first-stage sand rinsing and a second-stage sand rinsing performed sequentially; the sand used for the first-stage sand rinsing is 200-400 mesh white corundum sand, and the sand used for the second-stage sand rinsing is 50-80 mesh white corundum sand.
[0012] Preferably, the parameters for 3D printing in step (1) include: a printing layer thickness of 0.10 to 0.25 mm, a laser power of 27 to 45 W, and an ambient temperature of 17 ± 1 °C during printing.
[0013] Preferably, the resin model in step (1) is a polystyrene resin model.
[0014] Preferably, the thickness of the paraffin coating in step (2) is 0.2 to 1.2 mm.
[0015] Preferably, the temperature of the paraffin wax during the application of the paraffin wax in step (2) is 68±2℃.
[0016] Preferably, step (2) further includes repairing, polishing, cleaning and drying the paraffin-coated product in sequence after applying the paraffin wax.
[0017] Preferably, the slurry used for coating comprises silica sol and corundum powder.
[0018] Preferably, the casting temperature in step (4) is 1500-1550℃.
[0019] The present invention provides a single crystal blade without striation defects prepared by the preparation method described in the above technical solution.
[0020] This invention provides the application of single-crystal blades without striation defects prepared by the preparation method described above, or the application of single-crystal blades without striation defects described above in aerospace engines and ground gas turbines.
[0021] This invention provides a method for preparing a single-crystal blade without striation defects, comprising the following steps:
[0022] (1) Import the model into a 3D printer for 3D printing to obtain a resin model; (2) Coat the resin model obtained in step (1) with paraffin wax to obtain a wax model; (3) Make a shell from the wax model obtained in step (2) to obtain a blade shell; (4) Cast the blade shell obtained in step (3) to obtain a single crystal blade without stripe crystal defects; the shell making in step (3) includes 9 coats of slurry and 8 sand rinsings; the coats of slurry and sand rinsings are performed alternately; the first sand rinsing in the sand rinsings includes a first-stage sand rinsing and a second-stage sand rinsing; the sand used in the first-stage sand rinsings is 200-400 mesh white corundum sand, and the sand used in the second-stage sand rinsings is 50-80 mesh white corundum sand. This invention utilizes 3D printing to prepare resin models, followed by wax molds. Compared to wax molds produced by injection molding using wax presses in industrial production, this method significantly increases the strength of the wax mold, effectively preventing fine micron-sized grit from infiltrating the mold and causing surface defects on the blade. Furthermore, by improving the sand-laden process, two different particle sizes of white corundum sand are used for the first sand-laden process. Using very fine 200-400 mesh white corundum sand for the first sand-laden process not only prevents grit from infiltrating the wax mold but also increases its strength. This reduces the problem of grit expanding towards the wax mold during sintering and causing surface defects, as seen in traditional methods using 80 mesh sand. The results of the embodiments show that the single-crystal blades prepared by the method provided by this invention have no striation crystal defects on their surface. Attached Figure Description
[0023] Figure 1 This is a photograph of the wax model prepared in Example 1 of the present invention.
[0024] Figure 2 These are physical images of the single-crystal blades without stripe crystal defects prepared in Examples 1-3 of the present invention;
[0025] Figure 3 The images show the physical specimens of the single-crystal blades prepared in Comparative Examples 1-4.
[0026] Figure 4 This is a back view of the single-crystal blade prepared in Comparative Example 1.
[0027] Figure 5 This is a back view of the single-crystal blade prepared in Comparative Example 3. Detailed Implementation
[0028] This invention provides a method for preparing a single-crystal blade without striation defects, comprising the following steps:
[0029] (1) Import the model into a 3D printer for 3D printing to obtain a resin model;
[0030] (2) Coat the resin model obtained in step (1) with paraffin wax to obtain a wax model;
[0031] (3) The wax model obtained in step (2) is used to make a shell to obtain a blade mold shell;
[0032] (4) Cast and directional solidify the blade mold shell obtained in step (3) to obtain a single crystal blade without stripe crystal defects;
[0033] The shell-making process in step (3) includes 9 coats of slurry and 8 sand rinsings; the coats of slurry and sand rinsings are performed alternately; the first sand rinsing includes a first-stage sand rinsing and a second-stage sand rinsing performed sequentially; the sand used for the first-stage sand rinsing is 200-400 mesh white corundum sand, and the sand used for the second-stage sand rinsing is 50-80 mesh white corundum sand.
[0034] Unless otherwise specified, all raw materials used in this invention are commercially available products well known to those skilled in the art.
[0035] This invention imports the model into a 3D printer for 3D printing to obtain a resin model.
[0036] This invention does not specify a particular model of 3D printer; any commercially available 3D printer well-known to those skilled in the art can be used. Similarly, this invention does not specify a particular shape or size of the model; it can be determined based on the required shape and size of the single-crystal blade.
[0037] In this invention, the parameters for 3D printing preferably include: a printing layer thickness of 0.10–0.25 mm, a laser power of 27–45 W, and an ambient temperature of 17 ± 1 °C during printing; more preferably: a printing layer thickness of 0.15–0.20 mm, a laser power of 30–40 W, and an ambient temperature of 17 ± 1 °C during printing; and even more preferably: a printing layer thickness of 0.15 mm, a laser power of 35 W, and an ambient temperature of 17 ± 1 °C during printing.
[0038] In this invention, the raw material used for 3D printing is preferably resin, and more preferably polystyrene resin.
[0039] In this invention, the resin model is preferably a polystyrene resin model.
[0040] This invention uses 3D printing to prepare resin models, and then prepares wax models. Compared with wax models produced by injection molding using wax presses, which are widely used in industrial production, the wax model strength can be increased several times. This effectively avoids the intrusion of fine micron-sized sand particles into the wax model during the shell-making process, which could lead to defects on the blade surface.
[0041] After obtaining the resin model, the present invention coats the resin model with paraffin wax to obtain a wax model.
[0042] In this invention, the thickness of the paraffin coating is preferably 0.2 to 1.2 mm, more preferably 0.4 to 1.0 mm, and even more preferably 0.5 to 0.8 mm.
[0043] In this invention, the temperature of the paraffin wax during application is preferably 68±2℃. By controlling the temperature of the paraffin wax application, this invention enables the paraffin wax to have good fluidity, thereby facilitating the control of the coating thickness.
[0044] In this invention, the preferred ambient temperature during paraffin wax application is 20±1℃; the preferred ambient humidity during paraffin wax application is 50%RH. By controlling the environmental parameters during paraffin wax application, this invention facilitates paraffin wax cooling and application, thereby controlling the coating thickness.
[0045] In this invention, the process of applying the paraffin wax preferably includes repairing, polishing, cleaning, and drying the paraffin wax-coated product in sequence.
[0046] The present invention does not impose any special limitation on the specific method of repair. Repair can be carried out in a manner known to those skilled in the art, as long as the thickness of the paraffin meets the requirements.
[0047] In this invention, the preferred polishing method is to use 3000-grit sandpaper. This invention improves the surface smoothness of the wax model by polishing it.
[0048] In this invention, the cleaning process preferably uses distilled water. This invention removes residual paraffin powder after polishing through cleaning.
[0049] In this invention, the drying method is preferably air drying.
[0050] After obtaining the wax model, the present invention will process the wax model into a shell to obtain the blade mold shell.
[0051] In this invention, the shell-making process includes nine coats of slurry and eight sand applications; the coats of slurry and sand applications are performed alternately. Preferably, the coats of slurry are performed first during the shell-making process.
[0052] In this invention, the composition of the slurry used for coating preferably includes silica sol and corundum powder; the mass percentage of Al2O3 in the corundum powder is preferably ≥99.8%.
[0053] In this invention, the slurry application is preferably performed with three surface layer slurry applications, two transition layer slurry applications, and four back layer slurry applications.
[0054] In this invention, the mass ratio of silica sol to corundum powder in the surface slurry used for the surface coating is preferably 1:(2.3-3), more preferably 1:2.3; the mass ratio of silica sol to corundum powder in the transition layer slurry used for the transition layer coating is preferably 1:2.2; and the mass ratio of silica sol to corundum powder in the back layer slurry used for the back layer coating is preferably 1:2.1.
[0055] The present invention does not impose any special limitations on the thickness and specific operation of the surface slurry, transition slurry and back slurry in the slurry coating process, which can be determined based on the technical common sense of those skilled in the art.
[0056] In this invention, the first sand rinsing process includes a primary sand rinsing and a secondary sand rinsing performed sequentially. The sand used in the primary sand rinsing is 200-400 mesh white corundum sand, preferably 325 mesh white corundum sand; the sand used in the secondary sand rinsing is 50-80 mesh white corundum sand, preferably 60 mesh white corundum sand. This invention improves the sand rinsing process by using two different particle sizes of white corundum sand for the first sand rinsing. Using very small particles of 200-400 mesh white corundum sand for the first rinsing makes it less likely to penetrate the wax mold, while also increasing the strength of the wax mold. This reduces the problem of surface defects caused by the expansion of gravel into the wax mold during sintering, which occurs in the traditional process when using 80 mesh sand for rinsing.
[0057] In this invention, the sand used in the second and third leaching processes is preferably 60-mesh white corundum sand; the sand used in the fourth and fifth leaching processes is preferably 40-mesh white corundum sand; and the sand used in the sixth, seventh, and eighth leaching processes is preferably 20-mesh white corundum sand. In this invention, the first, second, and third leaching processes are surface layer sand, the fourth and fifth leaching processes are transition layer sand, and the sixth, seventh, and eighth leaching processes are back layer sand.
[0058] After obtaining the blade mold shell, the present invention casts the blade mold shell to obtain a single crystal blade without stripe crystal defects.
[0059] The present invention preferably involves heat preservation treatment of the blade mold shell before casting; the heat preservation temperature is preferably 1500-1600℃, more preferably 1550℃. The present invention does not have a specific limitation on the heat preservation time; based on the technical knowledge of those skilled in the art, it is sufficient to ensure that the temperature of the blade mold shell reaches 1500-1600℃. By heat preservation treatment of the blade mold shell, the present invention can make the temperature of the blade mold shell similar to that of the molten metal, thereby avoiding performance degradation caused by rapid cooling of the molten metal during casting.
[0060] In this invention, the casting temperature is preferably 1500–1550°C, more preferably 1500°C. In this invention, the pulling rate for directional solidification is preferably 3–7 mm / min, more preferably 4–6 mm / min, and even more preferably 5 mm / min.
[0061] After directional solidification, the present invention preferably performs shell removal and acid leaching on the directional solidification product in sequence to obtain a single-crystal blade without striation defects. The present invention does not have specific limitations on the specific operations of shell removal and acid leaching; operations well known to those skilled in the art can be used to remove the blade mold shell from the surface of the single-crystal blade.
[0062] This invention uses 3D printing to prepare resin models, which are then used to prepare wax models. Compared to wax models produced by injection molding using wax presses, which are widely used in industrial production, this method can increase the strength of the wax model several times. It effectively prevents fine micron-sized sand particles from infiltrating the wax model during the shell-making process, thus avoiding defects on the blade surface. By improving the sand-laden process, two different particle sizes of white corundum sand are used for the first sand-laden process. Using very fine 200-400 mesh white corundum sand for the first sand-laden process makes it less likely for sand particles to infiltrate the wax model, while also increasing the strength of the wax model. This reduces the problem of sand particles expanding towards the wax model during the sintering process and infiltrating the wax model, causing surface defects, which is a common issue in traditional processes using 80 mesh sand for the first sand-laden process.
[0063] The preparation method provided by this invention is simple, requires little equipment, and can improve the product qualification rate of single crystal blades while reducing production costs.
[0064] The present invention provides a single crystal blade without striation defects prepared by the preparation method described in the above technical solution.
[0065] The present invention also provides the application of the single crystal blade without striation defects prepared by the preparation method described above, or the single crystal blade without striation defects described above, in aerospace engines and ground gas turbines.
[0066] The present invention does not impose any special limitations on the specific application method, which can be determined based on the technical common sense of those skilled in the art.
[0067] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.
[0068] Example 1
[0069] A method for preparing a single-crystal blade without striation defects comprises the following steps:
[0070] (1) Import the model into a 3D printer for 3D printing to obtain a polystyrene resin model; the parameters for 3D printing are: the printing layer thickness is 0.15mm, the laser power is 35W, and the ambient temperature during printing is 17±1℃.
[0071] (2) The resin model obtained in step (1) is coated with paraffin wax, and then repaired, polished with 3000-grit sandpaper, washed with distilled water and dried to obtain a wax model; the thickness of the paraffin wax coating is 0.8 mm; the temperature of the paraffin wax coating is 68±2℃; the ambient temperature during the paraffin wax coating is 20±1℃ and the humidity is 50%RH.
[0072] (3) The wax model obtained in step (2) is used to make a shell to obtain a blade shell; the shell making is performed by 9 times of slurry application and 8 times of sand application, the slurry application and sand application are performed alternately and the slurry application is performed first; the first sand application is performed sequentially by first-level sand application and second-level sand application; the sand used for the first-level sand application is 325-mesh white corundum sand, the sand used for the second-level sand application is 60-mesh white corundum sand; the sand used for the second and third sand applications is 60-mesh white corundum sand, the sand used for the fourth and fifth sand applications is 40-mesh white corundum sand, and the sand used for the sixth, seventh and eighth sand applications is 20-mesh white corundum sand; The first, second, and third sand leaching processes are surface layer sand, the fourth and fifth sand leaching processes are transition layer sand, and the sixth, seventh, and eighth sand leaching processes are back layer sand; the slurry application consists of three surface layer slurries, two transition layer slurries, and four back layer slurries; the mass ratio of silica sol to corundum powder in the surface layer slurry used for surface layer slurry application is 1:2.3; the mass ratio of silica sol to corundum powder in the transition layer slurry used for transition layer slurry application is 1:2.2; the mass ratio of silica sol to corundum powder in the back layer slurry used for back layer slurry application is 1:2.1; the Al2O3 mass percentage content in the corundum powder is ≥99.8%;
[0073] (4) The blade mold shell obtained in step (3) is kept at 1550℃ and then cast at 1500℃. Then, directional solidification is carried out at a pulling rate of 5mm / min. Finally, the blade mold shell and acid washing are removed in sequence to obtain a single crystal blade without stripe crystal defects.
[0074] The actual image of the wax model prepared in Example 1 is shown below. Figure 1 As shown. By Figure 1 It can be seen that the wax mold obtained by the preparation method of the present invention has no surface defects, and after testing, the tensile strength of the wax mold is about 50 MPa, which is higher.
[0075] Example 2
[0076] A method for preparing a single-crystal blade without striation defects comprises the following steps:
[0077] (1) Import the model into a 3D printer for 3D printing to obtain a polystyrene resin model; the parameters for 3D printing are: the printing layer thickness is 0.15mm, the laser power is 30W, and the ambient temperature during printing is 17±1℃.
[0078] (2) The resin model obtained in step (1) is coated with paraffin wax, and then repaired, polished with 3000-grit sandpaper, washed with distilled water and dried to obtain a wax model; the thickness of the paraffin wax coating is 0.8 mm; the temperature of the paraffin wax coating is 68±2℃; the ambient temperature during the paraffin wax coating is 20±1℃ and the humidity is 50%RH.
[0079] (3) The wax model obtained in step (2) is used to make a shell to obtain a blade shell; the shell making is performed by 9 times of slurry application and 8 times of sand application, the slurry application and sand application are performed alternately and the slurry application is performed first; the first sand application is performed sequentially by first-level sand application and second-level sand application; the sand used for the first-level sand application is 300-mesh white corundum sand, the sand used for the second-level sand application is 60-mesh white corundum sand; the sand used for the second and third sand applications is 60-mesh white corundum sand, the sand used for the fourth and fifth sand applications is 40-mesh white corundum sand, and the sand used for the sixth, seventh and eighth sand applications is 20-mesh white corundum sand; The first, second, and third sand leaching processes are surface layer sand, the fourth and fifth sand leaching processes are transition layer sand, and the sixth, seventh, and eighth sand leaching processes are back layer sand; the slurry application consists of three surface layer slurries, two transition layer slurries, and four back layer slurries; the mass ratio of silica sol to corundum powder in the surface layer slurry used for surface layer slurry application is 1:2.3; the mass ratio of silica sol to corundum powder in the transition layer slurry used for transition layer slurry application is 1:2.2; the mass ratio of silica sol to corundum powder in the back layer slurry used for back layer slurry application is 1:2.1; the Al2O3 mass percentage content in the corundum powder is ≥99.8%;
[0080] (4) The blade mold shell obtained in step (3) is kept at 1550℃ and then cast at 1500℃. Then, directional solidification is carried out at a pulling rate of 5mm / min. Finally, the blade mold shell and acid washing are removed in sequence to obtain a single crystal blade without stripe crystal defects.
[0081] Example 3
[0082] A method for preparing a single-crystal blade without striation defects comprises the following steps:
[0083] (1) Import the model into a 3D printer for 3D printing to obtain a polystyrene resin model; the parameters for 3D printing are: the printing layer thickness is 0.15mm, the laser power is 40W, and the ambient temperature during printing is 17±1℃.
[0084] (2) The resin model obtained in step (1) is coated with paraffin wax, and then repaired, polished with 3000-grit sandpaper, washed with distilled water and dried to obtain a wax model; the thickness of the paraffin wax coating is 0.8 mm; the temperature of the paraffin wax coating is 68±2℃; the ambient temperature during the paraffin wax coating is 20±1℃ and the humidity is 50%RH.
[0085] (3) The wax model obtained in step (2) is used to make a shell to obtain a blade shell; the shell making is performed by 9 times of slurry application and 8 times of sand application, the slurry application and sand application are performed alternately and the slurry application is performed first; the first sand application is performed sequentially by first-level sand application and second-level sand application; the sand used for the first-level sand application is 350-mesh white corundum sand, the sand used for the second-level sand application is 60-mesh white corundum sand; the sand used for the second and third sand applications is 60-mesh white corundum sand, the sand used for the fourth and fifth sand applications is 40-mesh white corundum sand, and the sand used for the sixth, seventh and eighth sand applications is 20-mesh white corundum sand; The first, second, and third sand leaching processes are surface layer sand, the fourth and fifth sand leaching processes are transition layer sand, and the sixth, seventh, and eighth sand leaching processes are back layer sand; the slurry application consists of three surface layer slurries, two transition layer slurries, and four back layer slurries; the mass ratio of silica sol to corundum powder in the surface layer slurry used for surface layer slurry application is 1:2.3; the mass ratio of silica sol to corundum powder in the transition layer slurry used for transition layer slurry application is 1:2.2; the mass ratio of silica sol to corundum powder in the back layer slurry used for back layer slurry application is 1:2.1; the Al2O3 mass percentage content in the corundum powder is ≥99.8%;
[0086] (4) The blade mold shell obtained in step (3) is kept at 1550℃ and then cast at 1500℃. Then, directional solidification is carried out at a pulling rate of 5mm / min. Finally, the blade mold shell and acid washing are removed in sequence to obtain a single crystal blade without stripe crystal defects.
[0087] Comparative Example 1
[0088] A method for preparing a single-crystal blade comprises the following steps:
[0089] (1) A wax mold is obtained by injection molding using a wax press;
[0090] (2) The wax model obtained in step (1) is used to make a shell to obtain a blade shell; the shell making is performed by 9 coats of slurry and 8 coats of sand, with the coats of slurry and sand being performed alternately and the coats of slurry being performed first; the sand is made with 80-mesh white corundum sand; the sand used for the second and third sanding is 60-mesh white corundum sand, the sand used for the fourth and fifth sanding is 40-mesh white corundum sand, and the sand used for the sixth, seventh and eighth sanding is 20-mesh white corundum sand; the first, second and third sanding are the surface layer. The sand used in the fourth and fifth leaching processes forms the transition layer sand, while the sixth, seventh, and eighth leaching processes form the back layer sand. The slurry application consists of three surface layer slurries, two transition layer slurries, and four back layer slurries. The mass ratio of silica sol to corundum powder in the surface layer slurry used for the surface layer slurry is 1:2.3. The mass ratio of silica sol to corundum powder in the transition layer slurry used for the transition layer slurry is 1:2.2. The mass ratio of silica sol to corundum powder in the back layer slurry used for the back layer slurry is 1:2.1. The corundum powder contains ≥99.8% Al2O3 by mass.
[0091] (3) The blade mold shell obtained in step (2) is kept at 1550℃ and then cast at 1500℃. Then, directional solidification is carried out at a pulling rate of 5mm / min. Finally, the blade mold shell and acid washing are removed in sequence to obtain a single crystal blade.
[0092] Comparative Example 2
[0093] A method for preparing a single-crystal blade comprises the following steps:
[0094] (1) A wax mold is obtained by injection molding using a wax press;
[0095] (2) The wax model obtained in step (1) is used to make a shell to obtain a blade shell; the shell making is performed by 9 coats of slurry and 8 coats of sand, with the coats of slurry and sand being performed alternately and the coats of slurry being performed first; the sand is made with 100-mesh white corundum sand; the sand used for the second and third sanding is 60-mesh white corundum sand, the sand used for the fourth and fifth sanding is 40-mesh white corundum sand, and the sand used for the sixth, seventh and eighth sanding is 20-mesh white corundum sand; the first, second and third sanding are the surface layer. The sand used in the fourth and fifth leaching processes forms the transition layer sand, while the sixth, seventh, and eighth leaching processes form the back layer sand. The slurry application consists of three surface layer slurries, two transition layer slurries, and four back layer slurries. The mass ratio of silica sol to corundum powder in the surface layer slurry used for the surface layer slurry is 1:2.3. The mass ratio of silica sol to corundum powder in the transition layer slurry used for the transition layer slurry is 1:2.2. The mass ratio of silica sol to corundum powder in the back layer slurry used for the back layer slurry is 1:2.1. The corundum powder contains ≥99.8% Al2O3 by mass.
[0096] (3) The blade mold shell obtained in step (2) is kept at 1550℃ and then cast at 1500℃. Then, directional solidification is carried out at a pulling rate of 5mm / min. Finally, the blade mold shell and acid washing are removed in sequence to obtain a single crystal blade.
[0097] Comparative Example 3
[0098] A method for preparing a single-crystal blade comprises the following steps:
[0099] (1) A wax mold is obtained by injection molding using a wax press;
[0100] (2) The wax model obtained in step (1) is used to make a shell to obtain a blade shell; the shell making is performed by 9 coats of slurry and 8 coats of sand, with the coats of slurry and sand being performed alternately and the coats of slurry being performed first; the sand is made with 120-mesh white corundum sand; the sand used for the second and third sands is 60-mesh white corundum sand, the sand used for the fourth and fifth sands is 40-mesh white corundum sand, and the sand used for the sixth, seventh and eighth sands is 20-mesh white corundum sand; the first, second and third sands are the surface layer. The sand used in the fourth and fifth leaching processes forms the transition layer sand, while the sixth, seventh, and eighth leaching processes form the back layer sand. The slurry application consists of three surface layer slurries, two transition layer slurries, and four back layer slurries. The mass ratio of silica sol to corundum powder in the surface layer slurry used for the surface layer slurry is 1:2.3. The mass ratio of silica sol to corundum powder in the transition layer slurry used for the transition layer slurry is 1:2.2. The mass ratio of silica sol to corundum powder in the back layer slurry used for the back layer slurry is 1:2.1. The corundum powder contains ≥99.8% Al2O3 by mass.
[0101] (3) The blade mold shell obtained in step (2) is kept at 1550℃ and then cast at 1500℃. Then, directional solidification is carried out at a pulling rate of 5mm / min. Finally, the blade mold shell and acid washing are removed in sequence to obtain a single crystal blade.
[0102] Comparative Example 4
[0103] A method for preparing a single-crystal blade comprises the following steps:
[0104] (1) A wax mold is obtained by injection molding using a wax press;
[0105] (2) The wax model obtained in step (1) is used to make a shell to obtain a blade shell; the shell making is performed by 9 coats of slurry and 8 coats of sand, with the coats of slurry and sand being performed alternately and the coats of slurry being performed first; the sand is made with 150-mesh white corundum sand; the sand used for the second and third sanding is 60-mesh white corundum sand, the sand used for the fourth and fifth sanding is 40-mesh white corundum sand, and the sand used for the sixth, seventh and eighth sanding is 20-mesh white corundum sand; the first, second and third sanding are the surface layer. The sand used in the fourth and fifth leaching processes forms the transition layer sand, while the sixth, seventh, and eighth leaching processes form the back layer sand. The slurry application consists of three surface layer slurries, two transition layer slurries, and four back layer slurries. The mass ratio of silica sol to corundum powder in the surface layer slurry used for the surface layer slurry is 1:2.3. The mass ratio of silica sol to corundum powder in the transition layer slurry used for the transition layer slurry is 1:2.2. The mass ratio of silica sol to corundum powder in the back layer slurry used for the back layer slurry is 1:2.1. The corundum powder contains ≥99.8% Al2O3 by mass.
[0106] (3) The blade mold shell obtained in step (2) is kept at 1550℃ and then cast at 1500℃. Then, directional solidification is carried out at a pulling rate of 5mm / min. Finally, the blade mold shell and acid washing are removed in sequence to obtain a single crystal blade.
[0107] Figure 2 The images show physical photos of the single-crystal blades without striation defects prepared in Examples 1-3. Figure 2 From top to bottom, the images show single-crystal blades without striation defects prepared in Examples 1-3.
[0108] Figure 3 The images show the physical specimens of the single-crystal blades prepared in Comparative Examples 1 to 4. Figure 3 From top to bottom, the images show the single-crystal blades prepared in Comparative Examples 1 to 4. Figure 4 for Figure 3 A photograph of the back side of the single-crystal blade prepared in Comparative Example 1. Figure 5 for Figure 3 A back view of the single-crystal blade prepared in Comparative Example 3. Figures 3-5 It can be seen that the single crystal blades prepared in Comparative Examples 1 to 4 have obvious striped crystal defects.
[0109] Depend on Figures 2-5 The comparison shows that the preparation method provided by the present invention can eliminate stripe crystal defects and improve the yield of single crystal blades.
[0110] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for preparing a single-crystal blade without striation defects, comprising the following steps: (1) Import the model into a 3D printer for 3D printing to obtain a resin model; (2) Coat the resin model obtained in step (1) with paraffin wax to obtain a wax model; (3) The wax model obtained in step (2) is used to make a shell to obtain a blade mold shell; (4) Cast and directional solidify the blade mold shell obtained in step (3) to obtain a single crystal blade without stripe crystal defects; The shell-making process in step (3) includes 9 coats of slurry and 8 sand rinsings; the coats of slurry and sand rinsings are performed alternately; the first sand rinsing includes a first-stage sand rinsing and a second-stage sand rinsing performed sequentially; the sand used for the first-stage sand rinsing is 200-400 mesh white corundum sand, and the sand used for the second-stage sand rinsing is 50-80 mesh white corundum sand.
2. The preparation method according to claim 1, characterized in that, The parameters for 3D printing in step (1) include: a printing layer thickness of 0.10 to 0.25 mm, a laser power of 27 to 45 W, and an ambient temperature of 17 ± 1 °C during printing.
3. The preparation method according to claim 1, characterized in that, The resin model in step (1) is a polystyrene resin model.
4. The method of claim 1, wherein, In step (2), the thickness of the paraffin coating is 0.2 to 1.2 mm.
5. The preparation method according to claim 1, characterized in that, In step (2), the temperature of the paraffin wax during application is 68±2℃.
6. The method of claim 1, wherein, Step (2) after applying the paraffin wax also includes repairing, polishing, cleaning and drying the paraffin wax coated product in sequence.
7. The preparation method according to claim 1, characterized in that, The slurry used for coating includes silica sol and corundum powder.
8. The method of claim 1, wherein, The casting temperature in step (4) is 1500-1550℃.
9. A single-crystal blade without striation defects prepared by the preparation method according to any one of claims 1 to 8.
10. The application of the single-crystal blade without striation defects prepared by the preparation method according to any one of claims 1 to 8 or the single-crystal blade without striation defects according to claim 9 in aerospace engines and ground gas turbines.