Method for controlling deformation of thin-wall blade

Abstract

The invention relates to the technical field of precision casting and material preparation, in particular to a control method for deformation of a thin-wall blade. The blade preparation process comprises the steps of wax pattern preparation, shell preparation, pouring cleaning and size inspection, a thin-wall blade wax pattern is obtained by adopting a prefabrication shaping method, wax pattern deformation control technical parameters are determined, the surface layer manufacturing and roasting process is emphatically controlled, the shell stability is guaranteed, the pouring process parameters are optimized, and pouring forming is carried out. And the casting is cleaned, and the size and metallurgical defects are detected. According to the method, the casting problem of size deviation caused by ultrathin blades due to light weight of an advanced engine is solved, the problems of low casting qualification rate, long production period, cost increase and the like caused by deformation of some ultrathin structural parts at present can be practically and effectively solved, and the method has relatively high economic benefits and long-term application prospects.

Description

Technical field:

[0001] The invention relates to the technical field of precision casting and material preparation, and in particular to a method for controlling deformation of thin-walled blades. Background technology:

[0002] Thin-walled blades are key parts for future large-scale gas turbine power turbines and compressors, as well as major structural parts for nuclear power generation devices. Blades are lightweight and ultra-thin. Due to their thin-walled structure, blade size and profile are prone to serious deformation during the casting process. Therefore, deformation control is one of the difficult problems in the casting process.

[0003] Impeller castings are mostly used in supercharger turbines, water jet propulsion rotors, gas turbine turbine discs and other key flow-through components and stress-bearing components for propulsion and supercharging. The structure of impeller castings is a thick hub in the center, surrounded by thin-walled blades distributed around the hub. The blades of this type of parts are open and evenly distributed. Due to the influence of propulsion efficiency or supercharging efficiency, high dimensional accuracy of the blades is required. Therefore, impeller castings are generally formed by precision casting to ensure the dimensional accuracy of the blades. However, due to the large change in solidification rate, the shrinkage of the hub generally causes deformation of the blades, and the shrinkage is difficult to control. During the investment casting process, the blades are often scrapped due to deformation.

[0004] The traditional method generally adopts the anti-deformation design to ensure the dimensional accuracy of the impeller blades, but in the precision casting process, the shell thickness of the blade is generally only 3 to 8 mm (the thinnest part is only 0.5 mm), causing the blade to be suspended. Due to the large thickness variation from the blade root to the blade tip and the distortion of the profile, it is generally difficult to achieve the required dimensional accuracy after multiple anti-deformation compensations. Another method is to add tie rods to the blade tip to fix the blade deformation to ensure the dimensional accuracy of the blade, but this method generally causes inconsistent deformation in the width direction of the blade tip due to the thin blade tip, and due to the arrangement of tie rods, the difficulty of shell making is greatly increased, and the precision casting mold shell is prone to cracking during the production process.

[0005] The Chinese invention patent with publication number CN113857430A proposes a blade deformation control method and application. The blade deformation control method includes the following steps: (1) designing a wax mold to ensure the accuracy of the wax parts; (2) preparing the wax parts and placing them in the mold; (3) assembling the mold group to fix the wax parts to prevent secondary deformation; (4) manufacturing the mold shell, drying and baking it, and measuring the size; (5) pouring the mold shell, cooling, cleaning, preparing the casting, and measuring the casting size; (6) correcting the casting at room temperature; (7) annealing to fix the shape, and performing three-coordinate detection after cooling. Its disadvantage is that this method is not suitable for thin-walled blades. The wax parts of thin-walled blades cool quickly and solidify instantly, and the wax parts have no correction effect. Summary of the invention

[0006] The purpose of the present invention is to provide a method for controlling the deformation of thin-walled blades, which not only solves the casting problem of dimensional deviation caused by ultra-thin blades due to lightweighting of advanced engines, but also can effectively solve the problems of low casting qualification rate, long production cycle and increased cost caused by deformation of some ultra-thin structural parts.

[0007] The technical solution of the present invention is:

[0008] A method for controlling deformation of thin-walled blades. The blade preparation process includes wax pattern preparation, shell preparation, pouring and cleaning, and size inspection processes. A pre-molding method is used to obtain a thin-walled blade wax pattern, and the wax pattern deformation control technical parameters are determined. By focusing on controlling the surface layer manufacturing process and the roasting process, the stability of the shell is ensured, the optimal pouring process parameters are designed, pouring is performed, and the casting is cleaned and the size and metallurgical defects are inspected.

[0009] In the control method for thin-wall blade deformation, the blade wax mold adopts a pre-setting method, the material of the setting mold is cast iron, and the size shrinkage rate is 0.5-1.0%.

[0010] The thin-wall blade deformation control method described above requires that the blade wax pattern preparation process parameters must match the size shrinkage rate of the molded tire. The process parameters are: wax material temperature 70-80°C, holding time 10-30s, injection pressure 2.0-5.0MPa, and the wax material is injected into the molded tire according to the process parameters.

[0011] The thin-walled blade deformation control method is as follows: take out the blade wax model, place the leaf pot downward on the shaping tire for 2 to 5 hours, form a module under the condition of an ambient temperature of 16 to 20°C, and immediately put it into cold water at 0 to 5°C.

[0012] The thin-wall blade deformation control method manufactures the shell surface layer under the conditions of an ambient temperature of 16-30° C. and a humidity of 30-50%.

[0013] In the method for controlling the deformation of thin-walled blades, zircon sand and silica sol are used during the surface layer manufacturing process, and the weight ratio between the two is controlled between 1:2 and 5.

[0014] In the control method for thin-wall blade deformation, the surface layer strength is between 3 and 10 MPa, and the surface layer thickness is between 3 and 5 mm.

[0015] In the method for controlling the deformation of thin-walled blades, during the baking process, the baking temperature of the shell is controlled between 800 and 1000°C.

[0016] The thin-wall blade deformation control method is as follows: after the shell is baked, casting is performed at a temperature within the range of 1500-1600°C; after casting, the casting is cleaned, the casting size is measured, and metallurgical defects are inspected.

[0017] The method for controlling the deformation of thin-walled blades is applicable to the casting process of all metal materials, and is particularly applicable to the precision casting process of ultra-thin structural parts in the field of nuclear power or ships.

[0018] The design idea of ​​the present invention is:

[0019] The present invention adopts a pre-formed method to obtain a thin-walled blade wax mold and determine the technical parameters for controlling the deformation of the wax mold. By focusing on controlling the surface layer manufacturing process and the roasting process, the stability of the shell casting process is ensured, and the entire casting process is comprehensively controlled and considered as a whole, the optimal process parameters are designed, casting is performed, and the casting is cleaned, and the size and metallurgical defects are detected to solve the problem of unqualified size caused by the deformation of solid thin and long blades, and realize the scientific understanding and effective management of the deformation problem in the casting process of thin-walled blades.

[0020] In addition, the blade wax pattern of the present invention adopts a pre-forming method, and the relationship and function between the forming tire and the blade wax pattern are: the size of the forming tire extends to 1.0-2.0% of the size of the wax pattern. Therefore, the material of the forming tire of the present invention is cast iron, and the size shrinkage rate is 0.5-1.0%. The pre-forming method supplements the shrinkage of the thin wall through reverse deformation, so that the size is controlled within the technical requirements.

[0021] The advantages and beneficial effects of the present invention are:

[0022] 1. The present invention is used for the preparation and production of thin-walled blades, and mainly solves the deformation problem of thin-walled blades.

[0023] 2. The present invention can be directly applied to actual production, has great practicality and controllability, and is beneficial to improving the quality and performance of parts. Description of the drawings:

[0024] Figure 1 This is the mold assembly morphology after the thin-walled blade wax mold is assembled in Example 1.

[0025] Figure 2 This is the shape of the thin-walled blade mold shell cast in Example 1.

[0026] Figure 3 This is the blade profile of the casting. Specific implementation method:

[0027] In the specific implementation process, the present invention provides a method for controlling the deformation of thin-walled blades, and the specific implementation process is as follows:

[0028] Firstly, the wax pattern of thin-walled blades was obtained by pre-forming method, and the technical parameters for controlling the deformation of the wax pattern were determined.

[0029] Then, the focus is on controlling the surface layer manufacturing process and the baking process, and proposing technical measures to ensure the stability of the shell;

[0030] After that, the casting is poured, cleaned and cut;

[0031] Finally, the castings are measured and inspected for metallurgical defects.

[0032] Among them, the blade has an ultra-thin structure, with the thinnest part being 0.5mm. Prepare the mold of the ultra-thin blade wax mold, and determine the wax mold preparation process parameters according to the deformation law of the wax mold: wax material temperature 70-80℃, holding time 10-30s, injection pressure 2.0-5.0MPa, inject the wax into the mold according to the process parameters, take it out at an ambient temperature of 16-20℃ after cooling, combine it into a module, and then immediately put it into cold water at 0-5℃. When coating the shell, take out the module, apply the surface layer, the surface layer uses zircon sand and silica sol, and the weight ratio between the two is controlled between 1:2-5; apply a certain thickness and bake it, and the temperature is controlled between 800-1000℃. After the shell is made, pouring is carried out, the temperature is in the range of 1500-1600℃, the casting is cleaned after pouring, and the casting size is measured and metallurgical defects are inspected.

[0033] The present invention is further described in detail below through examples and drawings.

[0034] Example 1

[0035] In this embodiment, a method for controlling the deformation of thin-walled blades is specifically implemented as follows:

[0036] The first batch of blades were remelted at 75°C, and the wax was injected into the press at a pressure of 3.2MPa. The pressure was maintained for 20s, and the wax was injected into the mold to form a blade wax mold. The blade wax mold was taken out, and the blade basin was placed down on the cast iron mold for 4 hours. The wax mold module was assembled at an ambient temperature of 20°C, and immediately placed in cold water at 0-3°C. When making the shell, the wax mold module was removed from the water and blown dry. Zircon sand was used to make the mold shell at an ambient temperature of 19°C and a humidity of 30-50%, and the weight ratio of silica sol: zircon sand was 2.5. After the mold shell was dried, it was baked at 950°C for 2h, with a surface layer thickness of 3.5mm and a surface layer hardness of 4MPa. After the baked mold shell was made, it was poured at 1590°C. After the casting was cooled, it was cleaned, the casting size was measured, and the metallurgical defects of the casting were inspected.

[0037] like Figure 1-Figure 2 As shown, the mold assembly morphology and the thin-walled blade mold shell morphology after the thin-walled blade wax mold cast in Example 1 are assembled. The degree of deformation of the wax mold is relatively small and within the dimensional tolerance.

[0038] like Figure 3 As shown, after inspection, the surface quality and size of the casting are qualified, and the blade profile is within the required range.

[0039] Example 2

[0040] In this embodiment, a method for controlling the deformation of thin-walled blades is specifically implemented as follows:

[0041] The first batch of blades were remelted at 80℃, and the wax was injected into the press at a pressure of 4.2MPa. The pressure was maintained for 28s, and the wax was injected into the molded tire to form a blade wax mold. The blade wax mold was taken out, and the blade basin was placed down on the cast iron molded tire for 2 hours. The wax mold module was assembled at an ambient temperature of 19℃, and immediately placed in 0-1℃ cold water after assembly. When making the shell, the wax mold module was removed from the water and blown dry. Zircon sand was used to make the mold shell under the conditions of ambient temperature of 20℃ and humidity of 40-50%, and the weight ratio of silica sol: zircon sand was 4. After the mold shell was dried, it was baked at 1000℃ for 2h, with a surface layer thickness of 4.5mm and a surface layer hardness of 3.9MPa. After the baked mold shell was made, it was poured at 1550℃. After the casting was cooled, it was cleaned, and the casting size was measured. At the same time, the metallurgical defects of the casting were inspected. The surface quality and size of the casting were qualified after inspection.

[0042] The results of the embodiments show that the method for controlling the deformation of thin-walled blades of the present invention is applied to the precision casting industry, is suitable for the manufacturing process of thin-walled blades, can also be extended to the casting process of all metal materials, and can effectively solve the problems of low casting qualification rate, long production cycle and increased cost caused by deformation of ultra-thin structural parts currently used in some other fields. It has high economic benefits and long-term application prospects.

Claims

1. A method for controlling deformation of thin-walled blades, characterized in that: The blade preparation process includes wax pattern preparation, shell preparation, pouring and cleaning, and size inspection. The pre-forming method is adopted to obtain the thin-walled blade wax pattern, and determine the technical parameters for controlling the deformation of the wax pattern. By focusing on controlling the surface layer manufacturing process and the roasting process, the stability of the shell is ensured, the optimal pouring process parameters are designed, the casting is performed, and the casting is cleaned, and the size and metallurgical defects are inspected.

2. The method for controlling deformation of thin-walled blades according to claim 1, characterized in that: The blade wax mold is made by a pre-molding method, the material of the mold is cast iron, and the size shrinkage rate is 0.5-1.0%.

3. The method for controlling deformation of thin-walled blades according to claim 2, characterized in that: The process parameters for preparing the blade wax pattern must match the size shrinkage rate of the molded tire. The process parameters are: wax temperature 70-80°C, holding time 10-30s, injection pressure 2.0-5.0MPa. The wax is injected into the molded tire according to the process parameters.

4. The method for controlling deformation of thin-walled blades according to claim 3, characterized in that: Take out the leaf wax model, lay the leaf pot face down on the shaping tire for 2 to 5 hours, form a module at an ambient temperature of 16 to 20°C, and immediately put it in cold water at 0 to 5°C.

5. The method for controlling deformation of thin-walled blades according to claim 1, characterized in that: The mold shell surface layer is manufactured under the conditions of an ambient temperature of 16 to 30° C. and a humidity of 30 to 50%.

6. The method for controlling deformation of thin-walled blades according to any one of claims 1 to 5, characterized in that: During the manufacturing process of the surface layer, zircon sand and silica sol are used, and the weight ratio between the two is controlled between 1:2 and 5.

7. The method for controlling deformation of thin-walled blades according to claim 6, characterized in that: The surface layer strength is between 3 and 10 MPa, and the surface layer thickness is between 3 and 5 mm.

8. The method for controlling deformation of thin-walled blades according to claim 6, characterized in that: During the firing process, the firing temperature of the shell is controlled between 800 and 1000°C.

9. The method for controlling deformation of thin-walled blades according to claim 8, characterized in that: After the shell is calcined, pouring is carried out at a temperature within the range of 1500-1600°C. After pouring, the casting is cleaned, the casting size is measured, and metallurgical defects are inspected.

10. The method for controlling deformation of thin-walled blades according to claim 1, characterized in that: This method is applicable to the casting process of all metal materials, and is particularly applicable to the precision casting process of ultra-thin structural parts in the nuclear power or shipbuilding fields.

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