Method for controlling wall thickness of wax mould of complex hollow single crystal turbine blade and wax mould

Abstract

The invention relates to the technical field of precision casting, in particular to a method for controlling the wall thickness of a wax mold of a complex hollow single crystal turbine blade and the wax mold. According to the method, ceramic cores are screened by obtaining the profile size of the sections, corresponding to the wall thickness points of the wax mold, of the ceramic cores; then, positioning bosses are matched with positioning holes, the screened ceramic mold cores are placed in a wax mold for positioning, wax is injected into the wax mold, and a blade wax mold is manufactured; detecting the wall thickness of a blade wax mold and the wall thickness of a corresponding casting, and obtaining a wall thickness change value; and finally, according to the wall thickness change value, the maximum value and the minimum value of the wall thickness of each detection point of the wax mold are obtained, so that the wall thickness of the wax mold produced subsequently is accurately controlled, the casting wall thickness out-of-tolerance caused by improper wax mold wall thickness control requirements is avoided, and the casting wall thickness qualification rate is increased. The problem that in the prior art, due to shrinkage of a ceramic core, the wall thickness of a wax mold of the single-crystal turbine working blade cannot meet the process requirement is solved.

Description

Technical Field

[0001] The invention relates to the technical field of precision casting, and in particular to a method for controlling the wall thickness of a wax mold of a complex hollow single crystal turbine blade and a wax mold. Background Art

[0002] Hollow turbine blades are the core hot end components of aircraft engines, and their performance directly determines the overall efficiency and reliability of the engine. In extreme working environments, blades must not only withstand the impact of high temperature and high pressure airflow, but also maintain sufficient strength and durability to ensure the safe operation of the engine. Therefore, the design and control of blade wall thickness is particularly important, which is directly related to the strength and life of the blade. Among them, whether the blade wall thickness meets the design requirements is an important indicator to ensure the strength of the turbine blade, which is mainly determined by the ceramic core-mold positioning matching. In the manufacturing process of the blade, the ceramic core is a key molding tool, and its size control and positioning accuracy directly affect the wall thickness uniformity and qualified rate of the blade wax mold. However, the ceramic core will produce certain shrinkage deformation during the pressing and sintering process, which is determined by the composition, particle size distribution and structural characteristics of the core material. This shrinkage deformation will cause the positioning deviation of the core in the wax mold, which in turn affects the wall thickness accuracy of the blade wax mold. In order to solve this problem, the industry has proposed a series of technical methods, such as adjusting the core position, reversely adjusting the size of the positioning element, grinding the core head and adhering the core support; adjusting the core position is to control the wall thickness distribution of the wax mold blade by adjusting the position of the core in the outer mold, but this method increases the complexity of the mold design and requires higher precision and quality control during the mold manufacturing process; reversely adjusting the size of the positioning element is to establish a ceramic core positioning error transmission model and a reverse adjustment model to determine the mapping relationship between the ceramic core wall thickness deviation and the positioning element compensation amount, and then use ultrasonic pulse reflection method and other measurement techniques to measure the wall thickness of the wax mold, and reverse adjust the size of the ceramic core positioning element according to the measurement results. This method can effectively calculate the size compensation of the ceramic core positioning element, thereby improving the hollow turbine blade wax mold. The molding efficiency and wall thickness accuracy are improved, but the reverse adjustment of the positioning element size requires the establishment of an accurate error transfer model and a reverse adjustment model, which requires technical personnel to have high mathematical and physical modeling capabilities. At the same time, advanced measurement techniques, such as ultrasonic pulse reflection method, are also required to accurately measure the wall thickness of the wax model, which further increases the complexity of the technology. In addition, slight errors in the operation process may lead to large deviations in the final result. Grinding the core head and adhering the core support is to reduce the gap between the core and the mold by grinding the core head and other parts of the ceramic core to improve the positioning accuracy. This method is usually combined with methods such as adjusting the core position and reverse adjusting the positioning element size to achieve the best wall thickness control effect. However, this method is complicated to operate, inefficient, requires a lot of time and manpower, and has high production costs.

[0003] The Chinese invention with publication number CN115351224A discloses a method for solving the wall thickness of complex hollow single crystal blades, including wax mold pressing: placing a ceramic core into a mold, setting support positioning points in the mold to limit the freedom of the ceramic core, and injecting molten wax liquid into the wax mold mold by a wax press through the injection molding process to obtain a molded wax mold, and then taking the molded wax mold out of the wax mold mold and finalizing it; X-ray detection of wall thickness detection: wall thickness detection of wax molds that pass the X-ray detection; wax mold assembly tree; casting: placing the mold shell into the single crystal chamber for casting. The operation is simple, and the wall thickness of the complex hollow single crystal blade is guaranteed by six-point positioning, and bottom pouring ensures that qualified castings are obtained. There is no need to perform the core head positioning and wax mold core support adjustment process in the traditional method, which can effectively improve the production efficiency of complex hollow single crystal blade castings. However, this method only involves the positioning of the ceramic core surface and does not achieve control over the size of the ceramic core. There is a problem of poor positioning consistency caused by the shrinkage of the ceramic core. In the later stage, the positioning system needs to be further adjusted or the core head needs to be manually polished or waxed for correction. The process is complicated and inefficient.

[0004] Therefore, how to control the size of the ceramic core and combine it with the precise positioning of the ceramic core in the wax mold so that the wall thickness of the wax mold of the single-crystal turbine working blade meets the strict process requirements is still a technical problem that needs to be solved urgently. Summary of the invention

[0005] In view of the problem in the prior art that the wall thickness of the wax mold of a single crystal turbine working blade cannot meet the process requirements due to the shrinkage of the ceramic core, the present invention provides a method for controlling the wall thickness of a wax mold of a complex hollow single crystal turbine blade and a wax mold.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention provides a method for controlling the wall thickness of a wax mold of a complex hollow single crystal turbine blade, comprising: Obtain the surface dimensions of the cross section corresponding to the thickness point of the ceramic core and the wax mold wall; The ceramic core is selected according to the profile size of the cross section corresponding to the thickness point of the ceramic core and the wax mold wall; The screened ceramic core is placed in the wax mold for positioning; wherein, during positioning, a positioning hole is provided at the middle position of the tenon of the ceramic core, and a positioning protrusion is provided at the position of the wax mold corresponding to the positioning hole; After the positioning is completed, wax is injected into the wax mold to obtain a blade wax mold; Detect the wall thickness of the blade wax mold, and use the blade wax mold to cast to obtain a casting, and detect the wall thickness of the casting at the corresponding detection points of the blade wax mold wall thickness; Obtain the wall thickness change value according to the blade wax model wall thickness and casting wall thickness; According to the wall thickness change value, the maximum and minimum values ​​of the wall thickness at each detection point of the wax model are obtained; According to the maximum and minimum wall thickness of each inspection point of the wax model, the wall thickness of the wax model produced subsequently is controlled.

[0007] Optionally, a six-point positioning method is used to obtain the profile dimensions of the cross-sections corresponding to the thickness points of the ceramic core and the wax mold wall.

[0008] Optionally, in the process of obtaining the surface dimensions of the cross-section corresponding to the wall thickness points of the ceramic core and the wax mold using the six-point positioning method, the selected positioning points include a first positioning point and a second positioning point set at the tenon of the ceramic core, a third positioning point set in the back basin direction, a fourth positioning point set in the exhaust direction, a fifth positioning point set in the intake direction, and a sixth positioning point set in the radial direction of the ceramic core.

[0009] Optionally, in the process of placing the screened ceramic core in the wax mold for positioning, the selection of positioning points is consistent with the positioning points in the six-point positioning method.

[0010] Optionally, the method of placing the screened ceramic core in the wax mold for positioning is: Using the positioning needles to respectively position the positions corresponding to the fourth positioning point and the fifth positioning point, fixing the position of the ceramic core in the wax mold pressing mold in the air inlet and outlet directions; Place the positioning protrusion of the wax mold into the positioning hole of the ceramic core to fix the tenon of the ceramic core in the position in the wax mold; Using the positioning pin to position the position corresponding to the sixth positioning point, the position of the ceramic core in the direction of the leaf height in the wax mold is fixed; The positions corresponding to the first positioning point, the second positioning point and the third positioning point are positioned respectively by using positioning needles to fix the position of the ceramic core in the direction of the basin back in the wax mold, thereby completing the positioning of the ceramic core in the wax mold.

[0011] Optionally, the positioning hole is a square hole, and the length and width of the hole are both 5-6 mm.

[0012] Optionally, ultrasonic testing is used to detect the wall thickness of the blade wax mold and the wall thickness of the casting.

[0013] Optionally, the method for obtaining the wall thickness change value according to the blade wax mold wall thickness and the casting wall thickness is:

[0014] in, a is the wall thickness change, a 2 is the wall thickness of the blade casting at a certain detection point, a 1 is the wax mold wall thickness corresponding to the blade casting wall thickness detection point.

[0015] Optionally, the method for obtaining the maximum and minimum values ​​of the wall thickness at each detection point of the wax model according to the wall thickness change value is:

[0016] in, a min is the minimum design requirement for the blade casting wall thickness test point b, a max The maximum value required for the blade casting wall thickness test point b is designed. a 3 is the reserved grinding amount for blade casting wall thickness detection point b; A min is the minimum value of the wall thickness control corresponding to the wall thickness detection point b of the blade wax model, A max is the maximum value of the wall thickness control of the blade wax model corresponding to the wall thickness detection point b, a It is the wall thickness change value from the wax pattern to the corresponding wall thickness detection point b of the casting.

[0017] The invention also provides a wax pattern mold, which adopts the above method to control the wall thickness.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The present invention discloses a method for controlling the wall thickness of a complex hollow single crystal turbine blade wax mold. The method selects the ceramic core by obtaining the profile dimensions of the cross section corresponding to the ceramic core and the wax mold wall thickness point; then, the selected ceramic core is placed in a wax mold for positioning, and wax is injected into the wax mold to obtain a blade wax mold; the wall thickness of the blade wax mold and the corresponding casting wall thickness are detected and the wall thickness change value is obtained; finally, according to the wall thickness change value, the maximum and minimum values ​​of the wall thickness of each detection point of the wax mold are obtained to accurately control the wall thickness of the wax mold produced subsequently, thereby avoiding the excessive wall thickness of the casting caused by improper requirements for the wax mold wall thickness control and improving the qualified rate of the casting wall thickness. When positioning the ceramic core in the wax mold, the method sets a positioning hole at the middle position of the tenon of the ceramic core and sets a positioning convex block at the corresponding position of the wax mold. The positioning hole and the positioning convex block are used to coordinate and position the center surface of the thick part of the ceramic core. The principle of the ceramic core shrinking toward the center is used to avoid the positioning deviation of the ceramic core in the wax mold caused by the unstable shrinkage of the thick part when the ceramic core surface is positioned, so as to minimize the influence of the shrinkage of the ceramic core on the positioning. While positioning the center surface of the ceramic core in the wax mold, the positioning deviation of the ceramic core in the wax mold caused by the shrinkage and deformation of the ceramic core surface is reduced, thereby avoiding the problem of uneven wall thickness of the wax mold and high scrap rate of the wax mold caused by the positioning deviation caused by the shrinkage of the ceramic core. The method reduces the probability of artificially adjusting the positioning of the ceramic core in the mold, such as grinding the core head, sticking wax sheets on the core head, or adjusting the positioning pins of the ceramic core in the outer mold, thereby reducing the factors of human influence in the production process and greatly improving the consistency and production efficiency of the product.

[0019] The six-point positioning method is used to obtain the cross-sectional surface dimensions corresponding to the wall thickness points of the ceramic core and the wax mold. This can greatly improve the measurement accuracy and more quickly obtain the cross-sectional surface dimensions corresponding to the wall thickness points of the ceramic core and the wax mold. This not only shortens the measurement time, but also provides timely data support for subsequent process adjustments, helping to speed up production progress.

[0020] In the process of obtaining the profile dimensions of the cross section corresponding to the wall thickness point of the ceramic core and the wax mold by the six-point positioning method, the selected positioning points include the first positioning point and the second positioning point set on the tenon of the ceramic core, the third positioning point set in the direction of the back basin, the fourth positioning point set in the exhaust direction, the fifth positioning point set in the air intake direction, and the sixth positioning point set in the radial direction of the ceramic core. Among them, the first positioning point and the second positioning point are the tenon positioning points, and the tenon is the key part of the ceramic core, and its shape and size are crucial to the positioning accuracy. By setting two positioning points on the tenon, the stability and accuracy of the ceramic core during the measurement process can be ensured, and these two positioning points can also effectively limit the freedom of the ceramic core in the translation and rotation directions, thereby improving the positioning accuracy. The third positioning point, the fourth positioning point and the fifth positioning point are the back basin, exhaust, and air intake direction positioning points respectively, which can ensure the all-round stability of the ceramic core during the measurement process, and they can also help calibrate the direction of the ceramic core to ensure that the core is in the correct posture during measurement. The sixth positioning point is a radial positioning point, which can further limit the freedom of the ceramic core in the radial direction, thereby improving the accuracy and stability of positioning. At the same time, it also helps to ensure the correct contact and alignment between the ceramic core and the measuring device during the measurement process.

[0021] In the process of placing the selected ceramic core in the wax mold for positioning, the selection of the positioning points is consistent with the positioning points in the six-point positioning method. In the process of detecting the ceramic core and positioning the wax mold, the consistency of the ceramic core wall thickness can be ensured before pressing the wax mold, and the size of the ceramic core that affects the wax mold wall thickness can be accurately controlled to reduce the scrap rate of the blade wax mold and the casting wall thickness, which helps to ensure the reliability of positioning. In the wax mold positioning of the ceramic core, stable support and reliable positioning are the key to ensuring the casting quality. The use of consistent positioning points can avoid casting defects caused by positioning deviations, such as dimensional deviations, shape distortion, etc. At the same time, the use of the same positioning points can simplify the operating process, reduce positioning time, improve production efficiency, and reduce production costs.

[0022] In the process of placing the screened ceramic core in the wax mold for positioning, the positioning pins are used to respectively position the positions corresponding to the fourth positioning point and the fifth positioning point, and the position of the ceramic core in the wax mold pressing mold in the direction of air intake and exhaust can be fixed, which can accurately fix the position of the ceramic core in the wax mold pressing mold in the direction of air intake and exhaust, and help ensure the correct posture of the ceramic core in the mold to avoid deviation or deformation during subsequent processing; the positioning protrusion of the wax mold is placed in the positioning hole of the ceramic core to fix the position of the tenon of the ceramic core in the wax mold, which can firmly fix the tenon of the ceramic core in the wax mold. While ensuring the position of the ceramic core in the mold, it helps to maintain the precise alignment between the ceramic core and the wax mold; using the positioning pin to locate the position corresponding to the sixth positioning point to fix the position of the ceramic core in the wax mold in the leaf height direction, helps to ensure the height of the ceramic core in the mold is consistent and avoid height errors during the machining process; using the positioning pin to locate the positions corresponding to the first positioning point, the second positioning point and the third positioning point respectively, to fix the position of the ceramic core in the wax mold in the basin back direction. This all-round positioning method further improves the stability and positioning accuracy of the ceramic core in the mold.

[0023] The positioning hole is a square hole, and the length and width of the hole are both 5 to 6 mm. The design of the square hole allows the positioning protrusion to be more accurately inserted and fixed in the hole, thereby ensuring the precise alignment between the ceramic core and the wax mold, which helps to reduce the error caused by inaccurate positioning during the processing. The shape of the square hole makes the positioning protrusion more stable in the hole and less likely to shake or deviate.

[0024] The ultrasonic testing method is used to test the wall thickness of the blade wax mold and the wall thickness of the casting, which has higher testing efficiency and more accurate results.

[0025] A wax mold adopts the above method to control the wall thickness. The mold has been used in the production of a certain type of gas turbine single crystal turbine blade and a certain type of aircraft engine single crystal turbine blade. The wax mold wall thickness is uniform, the casting wall thickness qualification rate is high and stable, and a large amount of manpower and material resources are saved for the workshop. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The present invention is a flow chart of a method for controlling the wall thickness of a wax mold of a complex hollow single crystal turbine blade.

[0027] Figure 2 It is a schematic diagram of six-point positioning of a ceramic core detected by a six-point positioning method in an embodiment of the present invention.

[0028] Figure 3 It is a schematic diagram of the positioning method of the ceramic core of the present invention in the wax mold.

[0029] Figure 4The figure is a side view of the positioning method of the ceramic core of the present invention in the wax mold.

[0030] Figure 5 It is an enlarged view of the AA section of the ceramic core tenon of the ceramic core of the present invention.

[0031] Among them, 1-the first positioning point, 2-the second positioning point, 3-the third positioning point, 4-the fourth positioning point, 5-the fifth positioning point, 6-the sixth positioning point, and 7-the positioning hole. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0033] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0034] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0035] See also Figure 1 The present invention discloses a method for controlling the wall thickness of a wax mold of a complex hollow single crystal turbine blade, which is characterized by comprising: S1: Get the surface dimensions of the cross section corresponding to the thickness point of the ceramic core and the wax mold wall, specifically: Optionally, the six-point positioning method is used to obtain the profile dimensions of the cross section corresponding to the thickness points of the ceramic core and the wax mold wall, see Figure 2In the process of obtaining the surface dimensions of the cross section corresponding to the wall thickness points of the ceramic core and the wax mold using the six-point positioning method, the selected positioning points include a first positioning point 1 and a second positioning point 2 set on the tenon of the ceramic core, a third positioning point 3 set in the direction of the back basin, a fourth positioning point 4 set in the exhaust direction, a fifth positioning point 5 set in the intake direction, and a sixth positioning point 6 set in the radial direction of the ceramic core.

[0036] S2: Ceramic cores are screened according to the surface dimensions of the cross-section corresponding to the wall thickness point of the ceramic core and the wax mold; according to the surface dimension tolerance requirements, ceramic cores that meet the surface dimension tolerance requirements are selected as qualified ceramic cores for the next step of positioning in the wax mold.

[0037] S3: placing the selected ceramic core in the wax mold for positioning; wherein, during positioning, a positioning hole 7 is provided in the middle position of the tenon of the ceramic core, and a positioning protrusion is provided at the position corresponding to the positioning hole 7 of the wax mold. During the positioning process, the selection of the positioning point is consistent with the positioning point in the six-point positioning method, preferably: the positioning hole is a square hole, the length and width of the hole are both 5-6mm, the gap between the mold protrusion in the air intake and exhaust direction and the corresponding surface of the ceramic core is about 0.05mm, the distance from the point on the positioning surface of the tenon positioning hole to the center plane of the ceramic core in the width direction is less than or equal to 1.5mm, and the radial gap between the positioning protrusion and the ceramic core positioning hole 7 is 0.20-0.45mm, see Figure 3 and Figure 4 , specifically: Use the positioning needle to position the positions corresponding to the fourth positioning point 4 and the fifth positioning point 5 respectively, and fix the position of the ceramic core in the wax mold compression mold in the air inlet and outlet directions; Place the positioning protrusion of the wax mold into the positioning hole 7 of the ceramic core to fix the position of the tenon of the ceramic core in the wax mold; Use the positioning pin to position the position corresponding to the sixth positioning point 6 to fix the position of the ceramic core in the direction of the leaf height in the wax mold; The first positioning point 1, the second positioning point 2 and the third positioning point 3 are positioned respectively by positioning needles to fix the position of the ceramic core in the wax mold in the direction of the basin back, thereby completing the positioning of the ceramic core in the wax mold.

[0038] S4: After the positioning is completed, wax is injected into the wax mold to obtain a blade wax mold, specifically: The molten wax liquid is injected into the wax mold to obtain a shaped wax mold, and the shaped wax mold is taken out from the wax mold and shaped to obtain a blade wax mold.

[0039] S5: Detect the wall thickness of the blade wax mold, and use the blade wax mold to cast to obtain a casting, and detect the wall thickness of the casting at the corresponding detection points of the blade wax mold wall thickness, specifically: The ultrasonic detection method is used to obtain the wall thickness of each detection point of the blade wax model, and then the wax model is assembled and cast to obtain a casting. The ultrasonic detection method is used to detect the detection points corresponding to the casting and the wax model to obtain the wall thickness of the corresponding detection points of the casting.

[0040] S6: Obtain the wall thickness change value according to the blade wax mold wall thickness and the casting wall thickness, specifically:

[0041] in, a is the wall thickness change, a 2 is the wall thickness of the blade casting at a certain detection point, a 1 is the wax mold wall thickness corresponding to the blade casting wall thickness detection point.

[0042] S7: According to the wall thickness change value, the maximum and minimum values ​​of the wall thickness of each detection point of the wax model are obtained, specifically:

[0043] in, a min is the minimum design requirement for the blade casting wall thickness test point b, a max The maximum value required for the blade casting wall thickness test point b is designed. a 3 is the reserved grinding amount for blade casting wall thickness detection point b; A min is the minimum value of the wall thickness control corresponding to the wall thickness detection point b of the blade wax model, A max is the maximum value of the wall thickness control of the blade wax model corresponding to the wall thickness detection point b, a It is the wall thickness change value from the wax pattern to the casting corresponding to the wall thickness detection point b, where the detection point b is a point on the blade casting.

[0044] S8: According to the maximum and minimum values ​​of the wall thickness at each inspection point of the wax mold, control the wall thickness of the wax mold in subsequent production. Specifically: after obtaining the maximum and minimum values ​​of the wall thickness at each inspection point of the wax mold, the thickness of the wax mold at the corresponding inspection point can be inspected according to the range of the maximum and minimum values. If the thickness is less than the minimum value at this inspection point, it is unqualified. If it is greater than the maximum value at this inspection point, it needs to be polished and adjusted so that its thickness meets the requirements of the maximum and minimum values.

[0045] Example 1 See also Figures 2 to 5 Taking a gas turbine single crystal turbine blade as an example, the casting wall thickness tolerance is ±0.25mm, the width of the ceramic core at the tenon is about 30mm, and the height of the ceramic core is about 130mm.

[0046] First, the six-point positioning method is used to detect the surface dimensions of the sections AA-AA, AB-AB, AC-AC and AD-AD corresponding to the wall thickness points of the ceramic core and the wax mold, and the surface dimension tolerance is ±0.20mm. Among them, the six positioning points in the six-point positioning method are consistent with the subsequent positioning of the ceramic core in the wax mold, namely: the first positioning point 1 and the second positioning point 2 located on the positioning surface of the ceramic core tenon, the third positioning point 3 located in the direction of the basin back, the fourth positioning point 4 and the fifth positioning point 5 located in the exhaust direction and the intake direction respectively, and the sixth positioning point 6 located in the radial direction of the ceramic core.

[0047] After obtaining the above-mentioned mold surface dimensions, the ceramic core with qualified mold surface dimensions is placed in the wax mold to press the wax mold. In the wax mold, the ceramic core is fixed in the wax mold by a six-point positioning method: The ceramic core is positioned in the wax mold die in the direction of air inlet and outlet by using a positioning needle at the fourth positioning point 4 and the fifth positioning point 5 on the side of the tenon positioning hole; the positioning protrusion of the blade wax mold die is placed into the positioning hole 7 at the tenon of the ceramic core to fix the positioning of the tenon of the ceramic core in the wax mold die; the tip of the ceramic core is positioned by the positioning needle at the fourth positioning point 4. The positioning hole 7 on the tenon of the ceramic core is designed as a rectangular hole with a specification of 5*6mm, the gap between the wax mold die protrusion in the direction of air inlet and outlet and the corresponding surface of the ceramic core is 0.05mm, and the distance from the point on the positioning surface of the positioning hole 7 on the tenon to the center plane of the width direction of the ceramic core at that location is less than or equal to 1.5mm.

[0048] The ceramic core is positioned in the blade height direction in the wax mold by placing the positioning pin into the gap of the blade tip of the ceramic core and contacting it with the sixth positioning point 6. The radial gap between the positioning protrusion and the positioning hole 7 is 0.45 mm.

[0049] The positioning of the back of the blade is performed by positioning the first positioning point 1, the second positioning point 2 and the third positioning point 3 on the tenon positioning surface, fixing the ceramic core in the back of the blade in the wax mold. Wax is injected into the blade wax mold to obtain a blade wax mold.

[0050] The ultrasonic detection method is used to obtain the wall thickness of each detection point of the blade wax model, and then the wax model is assembled and cast to obtain a casting. The ultrasonic detection method is used to detect the detection points corresponding to the casting and the wax model to obtain the wall thickness of the corresponding detection points of the casting.

[0051] According to the blade wax model wall thickness and casting wall thickness, obtain the wall thickness change value:

[0052] in, a is the wall thickness change, a 2 is the wall thickness of the blade casting at a certain detection point,a 1 is the wax mold wall thickness corresponding to the blade casting wall thickness detection point.

[0053] According to the wall thickness change value, obtain the maximum and minimum values ​​of the wall thickness at each detection point of the wax model:

[0054] in, a min is the minimum design requirement for the blade casting wall thickness test point b, a max The maximum value required for the design of the blade casting wall thickness detection point b; A min is the minimum value of the wall thickness control corresponding to the wall thickness detection point b of the blade wax model, A max is the maximum value of the wall thickness control of the blade wax model corresponding to the wall thickness detection point b, a It is the wall thickness change value from the wax pattern to the corresponding wall thickness detection point b of the casting.

[0055] After obtaining the maximum and minimum values ​​of the wall thickness at each inspection point of the wax model, the thickness of the wax model mold at the corresponding inspection point can be detected based on the range of the maximum and minimum values. If the thickness is less than the minimum value at this inspection point, it is unqualified. If it is greater than the maximum value at this inspection point, it needs to be polished and adjusted so that its thickness meets the maximum and minimum requirements.

[0056] According to the above requirements, the wax mold wall thickness is detected and controlled to obtain a wax mold of parts with wall thickness that meets the requirements.

[0057] Example 2 See also Figures 2 to 5 Taking a certain aircraft single crystal turbine blade as an example, the wall thickness tolerance is ±0.20mm, the widest width of the ceramic core tenon is about 55mm, and the ceramic core height is about 100mm; The six-point positioning method is used to detect the surface dimensions of the sections AA-AA, AB-AB and AC-AC corresponding to the wall thickness points of the ceramic core and the wax mold, and the surface dimension tolerance is ±0.15mm. Among them, the six positioning points in the six-point positioning method are consistent with the positioning of the ceramic core in the wax mold, namely: the first positioning point 1 and the second positioning point 2 on the positioning surface of the ceramic core tenon, the third positioning point 3 located in the direction of the basin back, the fourth positioning point 4 and the fifth positioning point 5 located in the exhaust direction and the intake direction respectively, and the sixth positioning point 6 located in the radial direction of the ceramic core.

[0058] The ceramic core with qualified size is placed in the wax mold to press the wax mold. In the wax mold, the ceramic core is fixed by six-point positioning: After obtaining the above-mentioned mold surface dimensions, the ceramic core with qualified mold surface dimensions is placed in the wax mold to press the wax mold. In the wax mold, the ceramic core is fixed in the wax mold by a six-point positioning method: The positioning pin is used to fix the ceramic core in the wax mold die at the fourth positioning point 4 and the fifth positioning point 5 on the side of the tenon positioning hole to position the ceramic core in the direction of air inlet and outlet in the wax mold; the positioning protrusion of the blade wax mold die is placed into the positioning hole 7 at the tenon of the ceramic core to fix the positioning of the ceramic core tenon in the wax mold die; the tip of the ceramic core is positioned by the positioning pin at the fourth positioning point 4. Among them, the positioning hole 7 on the tenon of the ceramic core is designed as a rectangular hole with a specification of 5*5mm, the gap between the wax mold die protrusion in the direction of air inlet and outlet and the corresponding surface of the ceramic core is 0.05mm, and the distance from the point on the positioning surface of the positioning hole 7 on the tenon to the center plane of the width direction of the ceramic core at that location is less than or equal to 1.5mm.

[0059] The ceramic core is positioned in the blade height direction in the wax mold by placing the positioning pin into the gap of the blade tip of the ceramic core and contacting it with the sixth positioning point 6. The gap between the positioning protrusion and the positioning hole 7 in the radial direction is 0.2 mm.

[0060] The positioning of the back of the blade is performed by positioning the first positioning point 1, the second positioning point 2 and the third positioning point 3 on the tenon positioning surface, fixing the ceramic core in the back of the blade in the wax mold. (Inject wax into the blade wax mold to obtain a blade wax mold.

[0061] The ultrasonic detection method is used to obtain the wall thickness of each detection point of the blade wax model, and then the wax model is assembled and cast to obtain a casting. The ultrasonic detection method is used to detect the detection points corresponding to the casting and the wax model to obtain the wall thickness of the corresponding detection points of the casting.

[0062] According to the blade wax model wall thickness and casting wall thickness, obtain the wall thickness change value:

[0063] in, a is the wall thickness change, a 2 is the wall thickness of the blade casting at a certain detection point, a 1 is the wax mold wall thickness corresponding to the blade casting wall thickness detection point.

[0064] According to the wall thickness change value, obtain the maximum and minimum values ​​of the wall thickness at each detection point of the wax model:

[0065] in, a min is the minimum design requirement for the blade casting wall thickness test point b, a max The maximum value required for the blade casting wall thickness test point b is designed.a 3 is the reserved grinding amount for blade casting wall thickness detection point b; A min is the minimum value of the wall thickness control corresponding to the wall thickness detection point b of the blade wax model, A max is the maximum value of the wall thickness control of the blade wax model corresponding to the wall thickness detection point b, a It is the wall thickness change value from the wax pattern to the corresponding wall thickness detection point b of the casting.

[0066] After obtaining the maximum and minimum values ​​of the wall thickness at each inspection point of the wax model, the thickness of the wax model mold at the corresponding inspection point can be detected based on the range of the maximum and minimum values. If the thickness is less than the minimum value at this inspection point, it is unqualified. If it is greater than the maximum value at this inspection point, it needs to be polished and adjusted so that its thickness meets the maximum and minimum requirements.

[0067] According to the above requirements, the wax mold wall thickness is detected and controlled to obtain a wax mold of parts with wall thickness that meets the requirements.

[0068] A wax mold adopts the above method to control the wall thickness. The mold has been used in the production of a certain type of gas turbine single crystal turbine blade and a certain type of aircraft engine single crystal turbine blade. The wax mold wall thickness is uniform, the casting wall thickness qualification rate is high and stable, and a large amount of manpower and material resources are saved for the workshop.

[0069] In summary, the present invention provides a method for controlling the wall thickness of a complex hollow single crystal turbine blade wax mold and a wax mold, and proposes a method for positioning the center surface of the thick part of the ceramic core. The principle of the ceramic core shrinking toward the center is used to avoid the ceramic core being positioned in the outer mold due to the unstable shrinkage of the thick part when the ceramic core surface is positioned, thereby avoiding the problem of uneven wall thickness of the wax mold and high scrap of the wax mold wall thickness. The method reduces the probability of manually adjusting the positioning of the ceramic core in the mold, such as grinding the core head, sticking a wax sheet on the core head, or adjusting the positioning pin of the ceramic core in the outer mold, thereby reducing the human influence factors in the production process and greatly improving the consistency and production efficiency of the product. By obtaining the wall thickness change of the corresponding detection points of the casting and the corresponding wax mold, and obtaining the minimum and maximum values ​​for the wax mold wall thickness control, the wall thickness of the blade wax mold can be accurately controlled, avoiding the excessive wall thickness of the casting caused by improper requirements for the wax mold wall thickness control, and improving the qualified rate of the casting wall thickness. This method has been applied in the production of a certain type of gas turbine single-crystal turbine blades and a certain type of aircraft engine single-crystal turbine blades. The wall thickness of the wax mold is uniform, and the qualified rate of the casting wall thickness is high and stable, saving a lot of manpower and material resources for the workshop.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to impose any limitation on the technical solution of the present invention. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solution can also be subjected to several simple modifications and substitutions, and these modifications and substitutions are also within the scope of protection covered by the claims.

Claims

1. A method for controlling the wall thickness of a complex hollow single crystal turbine blade wax mold, characterized in that: include: Obtain the surface dimensions of the cross section corresponding to the thickness point of the ceramic core and the wax mold wall; The ceramic core is selected according to the profile size of the cross section corresponding to the thickness point of the ceramic core and the wax mold wall; The screened ceramic core is placed in the wax mold for positioning; wherein, during positioning, a positioning hole is provided at the middle position of the tenon of the ceramic core, and a positioning protrusion is provided at the position of the wax mold corresponding to the positioning hole; After the positioning is completed, wax is injected into the wax mold to obtain a blade wax mold; Detect the wall thickness of the blade wax mold, and use the blade wax mold to cast to obtain a casting, and detect the wall thickness of the casting at the corresponding detection points of the blade wax mold wall thickness; Obtain the wall thickness change value according to the blade wax model wall thickness and casting wall thickness; According to the wall thickness change value, the maximum and minimum values ​​of the wall thickness at each detection point of the wax model are obtained; According to the maximum and minimum wall thickness of each inspection point of the wax model, the wall thickness of the wax model produced subsequently is controlled.

2. The method for controlling the wall thickness of a complex hollow single crystal turbine blade wax mold according to claim 1, characterized in that: The six-point positioning method is used to obtain the surface dimensions of the cross section corresponding to the thickness points of the ceramic core and the wax mold wall.

3. The method for controlling the wall thickness of a complex hollow single crystal turbine blade wax mold according to claim 2, characterized in that: In the process of obtaining the surface dimensions of the cross-section corresponding to the wall thickness points of the ceramic core and the wax mold using the six-point positioning method, the selected positioning points include a first positioning point and a second positioning point set at the tenon of the ceramic core, a third positioning point set in the back basin direction, a fourth positioning point set in the exhaust direction, a fifth positioning point set in the intake direction, and a sixth positioning point set in the radial direction of the ceramic core.

4. The method for controlling the wall thickness of a complex hollow single crystal turbine blade wax mold according to claim 3, characterized in that: In the process of placing the selected ceramic core in the wax mold for positioning, the selection of the positioning points is consistent with the positioning points in the six-point positioning method.

5. The method for controlling the wall thickness of a complex hollow single crystal turbine blade wax mold according to claim 4, characterized in that: The method for placing the screened ceramic core in the wax mold for positioning is: Using the positioning needles to position the positions corresponding to the fourth positioning point and the fifth positioning point respectively, fixing the position of the ceramic core in the wax mold pressing mold in the air inlet and outlet directions; Place the positioning protrusion of the wax mold into the positioning hole of the ceramic core to fix the tenon of the ceramic core in the position in the wax mold; Using the positioning pin to position the position corresponding to the sixth positioning point, the position of the ceramic core in the direction of the leaf height in the wax mold is fixed; The positions corresponding to the first positioning point, the second positioning point and the third positioning point are positioned respectively by using positioning needles to fix the position of the ceramic core in the direction of the basin back in the wax mold, thereby completing the positioning of the ceramic core in the wax mold.

6. The method for controlling the wall thickness of a complex hollow single crystal turbine blade wax mold according to claim 1, characterized in that: The positioning hole is a square hole, and the length and width of the hole are both 5-6 mm.

7. The method for controlling the wall thickness of a complex hollow single crystal turbine blade wax mold according to claim 1, characterized in that: The ultrasonic testing method is used to detect the wall thickness of the blade wax model and the wall thickness of the casting.

8. The method for controlling the wall thickness of a complex hollow single crystal turbine blade wax mold according to claim 1, characterized in that: The method for obtaining the wall thickness change value according to the blade wax mold wall thickness and the casting wall thickness is: in, a is the wall thickness change, a 2 is the wall thickness of the blade casting at a certain detection point, a 1 is the wax mold wall thickness corresponding to the blade casting wall thickness detection point.

9. The method for controlling the wall thickness of a complex hollow single crystal turbine blade wax mold according to claim 1, characterized in that: The method for obtaining the maximum and minimum values ​​of the wall thickness at each detection point of the wax model according to the wall thickness change value is: in, a min is the minimum design requirement for the blade casting wall thickness test point b, a max The maximum value required for the blade casting wall thickness test point b is designed. a 3 is the reserved grinding amount for blade casting wall thickness detection point b; A min is the minimum value of the wall thickness control corresponding to the wall thickness detection point b of the blade wax model, A max is the maximum value of the wall thickness control of the blade wax model corresponding to the wall thickness detection point b, a It is the wall thickness change value from the wax pattern to the corresponding wall thickness detection point b of the casting.

10. A wax model mold, characterized in that: The wall thickness is controlled by the method described in any one of claims 1 to 9.

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