A method for die forging aerofoil blade

Abstract

The application discloses an aviation aircraft blade die forging forming method and belongs to the technical field of aircraft part processing. The method comprises the following steps: S1, blanking; S2, first spraying; S3, top forging; S4, second spraying; S5, top forging material heating; S6, pre-forging piece processing; S7, pre-forging piece heating and finish forging; and S8, post-processing of the finish forging piece. The forging method can make detailed division of the temperature of each heating time in the blade production process, can control the temperature below the phase change point according to the forging structure and the material phase change temperature, can make the forging maintain a low deformation resistance, can determine the heat treatment time and temperature in a targeted manner, can set the striking energy of the screw press in the forging process, can make the obtained finish forging piece have a uniform organizational state and good mechanical properties, can meet the use requirements, and has a high product yield.

Description

Technical Field

[0001] This invention relates to the field of aircraft component processing technology, and specifically to a method for die forging aircraft blades. Background Technology

[0002] As the performance and usage requirements of aero-engines continue to increase, the demands on the performance and blade profile of materials used in manufacturing aero-engine blades are also becoming increasingly stringent. Titanium alloys possess excellent comprehensive properties, including low density, high specific strength, and good toughness and weldability. Titanium's specific strength is higher than that of aluminum alloys and steel, and its toughness is comparable to that of steel, leading to its widespread application in aerospace, petrochemical, and shipbuilding industries. In aero-engines, titanium alloys are primarily used to manufacture fan and compressor discs, blades, casings, and various types of fasteners. Their usage exceeds 70% in the aerospace industry, and replacing structural steel with titanium alloys can reduce the weight of parts by approximately 30%. Compressor blades, as one of the key components of an aero-engine, are complex in structure, require high precision, involve complex processing techniques, and are numerous. Generally, blade machining accounts for 30-40% of the total machining workload of the entire engine. Compressor blades must possess excellent metallurgical properties, precise dimensions, and excellent surface integrity; therefore, compressor blade manufacturing technology is one of the most complex technologies in the manufacturing industry.

[0003] Existing processes uniformly define the heat treatment temperatures for each heat treatment stage in the forging process, without segmented treatment. Furthermore, with only one heat treatment, the transfer time for titanium alloy forgings is relatively long. This excessive transfer time results in an excessively low outer layer temperature of the titanium alloy billet. Upon contact with the lower-temperature mold cavity, the local temperature of the forging drops even faster, causing cracking and damage in areas of lower temperature during deformation, thus reducing the forging yield. Moreover, the use of glass lubricant only once in three forging stages reduces the heat preservation effect during the subsequent two die forging stages and also creates difficulties in demolding after forging. This further prolongs the forging transfer time, lowers the forging temperature, increases the forging's deformation resistance, and makes the material prone to cracking during forging.

[0004] The main forging characteristic of titanium alloys is their reactive chemical properties, making them highly susceptible to hydrogen and oxygen absorption, which leads to the formation of a brittle surface layer and reduced plasticity. Furthermore, the metal surface generated during forging adheres firmly to the die surface, causing both the forging and the die to be scrapped. Therefore, forging requires coating with a glass-based protective lubricant to separate the forging from the die. After coating with this lubricant, the coefficient of friction between the billet and the die is significantly reduced, lowering the forging pressure and mitigating the adverse effect of high deformation resistance in titanium alloys. In addition, coating the billet with this lubricant reduces the temperature drop of the billet and prevents or reduces the formation of a brittle surface layer on the forging, thus reducing its performance. Summary of the Invention

[0005] To address the problems existing in the background art, the present invention provides a method for die forging aircraft blades, comprising the following steps:

[0006] S1. Blank cutting:

[0007] Chamfer both ends of the billet and then place it in an electric furnace at a temperature of 150~180℃ and hold for 30~60 minutes.

[0008] S2, One-time spraying:

[0009] After heat preservation, the material is removed and a glass lubricant is evenly sprayed onto the surface of the blank. The thickness of the glass lubricant coating is 0.03~0.05mm. After spraying, the glass lubricant is allowed to dry and cure naturally to obtain the treated material.

[0010] S3, upsetting;

[0011] Preheat the charging furnace to T. β The material is heated to -40℃, then placed in a preheated furnace and held for 28-32 minutes. It is then placed in a preheated mold for upsetting to obtain the upset part; wherein, the T... β The phase transformation point temperature of the billet;

[0012] S4, Second coat:

[0013] The upsetting part is then sprayed with a second coating. The upsetting part is placed in an electric furnace at a temperature of 150~180℃ and held for 30~60 minutes. After being removed, a glass lubricant is sprayed onto the surface of the upsetting part. The coating thickness of the glass lubricant is 0.03~0.05mm. After the spraying is completed, the glass lubricant is allowed to dry and cure naturally to obtain the upsetting material.

[0014] S5. Heating of the forging material:

[0015] Preheat the charging furnace to T. β -40℃, then put in the forging material and hold for 35~40min; put the forging material into the preheated mold for pre-forging to obtain the pre-forged part. The operation time from the forging material leaving the furnace to the completion of forging is less than or equal to 15s.

[0016] S6. Pre-forging treatment:

[0017] Polish and grind the pre-forged parts, then perform dimensional etching with a single-sided etching amount of 0.07~0.1mm; then spray the pre-forged parts three times, place them in an electric furnace at a temperature of 150~180℃ and hold for 30~60 minutes, remove them and spray glass lubricant on the surface of the pre-forged parts, with a coating thickness of 0.03~0.05mm, and allow the glass lubricant to dry and cure naturally after spraying.

[0018] S7. Heating and final forging of pre-forged parts:

[0019] Based on the phase change temperature T of the raw material β Determine the heating temperature of the pre-forged part after step S6, and heat it at a constant temperature for 16~22 minutes. Then, place it in a preheated mold for final forging to obtain the final forging part. The operation time from the final forging part being taken out of the furnace to the completion of forging should not exceed 10 seconds.

[0020] Explanation: This forging method meticulously divides the temperature of each heat treatment during blade production, allowing for the determination of heat treatment coefficients based on the forging structure and material phase transformation temperature. By controlling the temperature below the phase transformation point, the forging maintains low deformation resistance, and the heat treatment time and temperature are specifically determined. Furthermore, the impact energy of the screw press during forging is set according to the amount of deformation. This results in a final forging with a uniform microstructure and good mechanical properties, meeting application requirements and achieving a high yield.

[0021] Furthermore, the method for determining the heating temperature of the pre-forging after step S6 is as follows: when T β When the temperature is ≤980℃, the heating temperature of the pre-forged part is T. β -40℃; when 980℃ <T β When the temperature is ≤990℃, the heating temperature of the pre-forged part is 940℃; when T β When the temperature is >990℃, the heating temperature of the pre-forged part is 950℃.

[0022] Explanation: By using the phase transformation point temperature of the material to set the heating temperature, the temperature is controlled below the phase transformation point. This maintains a lower deformation resistance in the forging, improving the yield strength, high-temperature creep performance, low-cycle fatigue life, fracture toughness, and crack propagation resistance of the material without reducing its plasticity and thermal stability. It also increases the service temperature, which is more conducive to the quality control of forged products. This avoids defects such as internal unevenness and folding that may occur during forging due to improper temperature and time settings, thus improving the overall performance of the finished forging.

[0023] Furthermore, it also includes: step S8, post-processing of the final forging:

[0024] S8-1. Trim the final forging in the mold using residual heat, and complete the trimming within 15 seconds after forging. Then, shot blast, grind, and shot blast again on the trimmed final forging until there are no defects or dirt on the surface to obtain the trimmed part.

[0025] S8-2. Place the cut-edge part into a warm-loading furnace for heating. The temperature inside the warm-loading furnace is 830~870℃, and the temperature is maintained for 10~15 minutes.

[0026] S8-3. Remove the cut edge part, use a mold for correction, and the operation time from the forging to the completion of forging is less than or equal to 10 seconds; then use shot blasting for surface treatment to obtain the aircraft blade.

[0027] Note: By further processing the final forging as described above, the surface properties of the resulting aircraft blades can be improved, avoiding defects such as scratches and cracks on the surface, and increasing the product qualification rate.

[0028] Furthermore, the shot blasting process conditions in step S8-1 are: shot blasting rate 200 kg / min, shot blasting time 15 min.

[0029] Note: By setting the shot blasting parameters as described above, it is possible to remove oxide scale and sand adhering to the surface of castings, and to ensure the reliability of the flaw detection results, thereby ensuring the quality of the finished product surface.

[0030] Furthermore, during the final forging process in step S7, the impact energy F1 is obtained using the Deform software simulation, and the impact energy F2 is calculated according to the following formula:

[0031] F2=KS / Q

[0032] In the formula, F is the nominal tonnage of the screw press, in tons; K is the forging coefficient, with a value of 5 tons / cm². 2 S represents the horizontal projected area of ​​the forging, in cm². 2 Q is the deformation coefficient, with a value of 1.1.

[0033] Then, the sum of 0.2*F1 and 0.8*F2 is calculated to obtain the strike energy budget value F. Then, through on-site forming experiments, k*F is obtained; the value of k ranges from 0.6 to 1.

[0034] Note: By using the above calculation and design methods for the impact energy of the final forging, the final forging can achieve a uniform microstructure and good mechanical properties. At the same time, compared with conventional impact energy, it can achieve the effect of saving energy consumption.

[0035] Furthermore, in the upsetting process of step S3, a flat forging machine is used with an impact energy of 630T; in the pre-forging process of step S5, a screw press is used with an impact energy of 625T; and in the final forging process of step S7, a screw press is used with an impact energy of 1000T.

[0036] Explanation: By setting the above multiple impact energies separately, a more optimal impact energy value can be set based on the temperature, the characteristics of forging itself, and the suitable deformation amount. This ensures a reasonable combination of deformation temperature and deformation amount, effectively preventing the formation of coarse and mixed grains in the material during forging, and obtaining high-quality forgings with uniform grains whose metallographic structure meets the design requirements.

[0037] Furthermore, the raw materials of the glass lubricant, by weight, include 20-25 parts of silicate glass powder, 18-25 parts of silicon dioxide, 8-16 parts of molybdenum trioxide, 6-15 parts of boromagnesia, 7-10 parts of vinyltrimethoxysilane, and 4-6 parts of aluminum dihydrogen phosphate.

[0038] Explanation: By setting the raw material components of the above-mentioned glass lubricant, a mixture of crystalline and amorphous glass powder is prepared by melting and mixing silicate glass powder, silicon dioxide, molybdenum trioxide, boromagnesia, vinyltrimethoxysilane and aluminum dihydrogen phosphate at high temperature. Compared with a single amorphous morphology, the presence of crystals reduces the adhesion of the glass lubricant, which is conducive to the molten coating peeling off from the titanium alloy profile substrate and facilitates the cleaning of the substrate surface after extrusion processing.

[0039] Furthermore, the method for preparing the glass lubricant includes the following steps:

[0040] S1-1. Silicate glass powder, silicon dioxide, molybdenum trioxide, and boromagnesia are mixed and ground into a mixed powder of 10~80μm. Then, vinyltrimethoxysilane and aluminum dihydrogen phosphate are added to the mixed powder and stirred evenly to obtain a mixture.

[0041] S1-2. The mixture obtained in step S1-1 is put into a high-temperature furnace and melted into molten glass; then cooled to room temperature to obtain a pre-finished product.

[0042] S1-3. Grind the pre-processed material obtained in step S1-2 to 0.5~10μm to obtain glass lubricant;

[0043] Note: The glass lubricant prepared by the above method has excellent chemical stability, lubricity and high temperature resistance. By mixing it in the form of mixed powder, the formation of each raw material component of the glass lubricant is more uniform, which can effectively reduce the generation of defects such as grooves and cracks on the surface of forgings and improve the surface quality of alloy extruded profiles.

[0044] Further, add 6% by mass of alcohol ester twelve and 30% by mass of deionized water to the glass lubricant obtained in steps S1-3, and perform ultrasonication in a water bath for 50-80 minutes. Then add 5% by mass of lithium titanate to the glass lubricant and stir for 1 hour to form a modified glass lubricant.

[0045] Explanation: Through further modification, the glass lubricant has good adhesion and dispersibility. The addition of 1,4-diol ester can enhance the film-forming effect, while its outstanding solvent effect and strong agglomeration ability, along with the strong fluxing properties of lithium titanate, allow it to simultaneously possess both adhesive and easy high-temperature detachment properties.

[0046] Furthermore, the spraying in step S2 uses the glass lubricant obtained in steps S1-3; the spraying in step S4 uses a mixed glass lubricant obtained in steps S1-3 and a modified glass lubricant mixed at a mass ratio of 1:3; and the spraying in step S6 uses a modified glass lubricant.

[0047] Note: The above-mentioned application of glass lubricant to multiple forging processes allows for differentiated processing using modified glass lubricant and regular glass lubricant, taking into account differences in material structure and heating temperature. This prevents oxidation and other chemical reactions on the alloy surface during processing, reduces material loss, provides good lubrication performance during forging, and ensures product precision and surface quality.

[0048] Furthermore, the billet is a TC4 alloy.

[0049] Note: TC4 alloy is a medium-strength α-β type two-phase titanium alloy containing 6% α-stabilizing element Al and 4% β-stabilizing element V; it has excellent comprehensive properties and has been widely used in the aerospace industry.

[0050] The beneficial effects of this invention are:

[0051] (1) By forging a blade, the present invention makes detailed divisions of the temperature of each heat treatment during the blade production process. It can determine the heat treatment coefficient according to the structure of the forging and the phase transformation temperature of the material, control the temperature below the phase transformation point, keep the forging with low deformation resistance, and determine the heat treatment time and temperature in a targeted manner. The impact energy of the screw press during the forging process is set according to the deformation amount. As a result, the final forging has a uniform microstructure and good mechanical properties, which can meet the requirements of use and the yield of the product is high.

[0052] (2) By using the phase transformation point temperature of the material to set the heating temperature, the present invention controls the temperature below the phase transformation point, and the forging maintains a low deformation resistance. The resulting structure improves the yield strength, high-temperature creep performance, low-cycle fatigue life, fracture toughness and crack propagation resistance of the material without reducing plasticity and thermal stability. It can also increase the service temperature, which is more conducive to the quality control of forging products. This avoids defects such as internal unevenness and folding caused by unreasonable temperature and time settings during the forging process, and improves the comprehensive performance of the finished forging. The present invention, by setting multiple impact energies separately, can set a more optimal impact energy value based on the temperature and the characteristics of forging itself and its suitable deformation, ensuring a reasonable combination of deformation temperature and deformation amount. It can effectively prevent the formation of coarse grains and mixed grains in the material during the forging process, and obtain high-quality forgings with uniform grains. The metallographic structure meets the design requirements.

[0053] (3) This invention, through the setting of raw material components of the glass lubricant, prepares a mixture of crystalline and amorphous glass powder by high-temperature melting and mixing silicate glass powder, silicon dioxide, molybdenum trioxide, borosilicate, alkenyltrimethoxysilane, and aluminum dihydrogen phosphate. Compared with a single amorphous morphology, the presence of crystals reduces the adhesion of the glass lubricant, which is conducive to the peeling of the molten coating off the titanium alloy profile substrate and facilitates the cleaning of the substrate surface after extrusion processing. The glass lubricant obtained by the above preparation method has excellent chemical stability, lubricity, and high temperature resistance. By mixing in the form of mixed powder, the formation between the raw material components of the glass lubricant is more uniform, which can effectively reduce the generation of defects such as grooves and cracks on the surface of forgings and improve the surface quality of alloy extruded profiles. Through further modification treatment, the glass lubricant has good adhesion and dispersibility. The addition of 1,4-diol ester can increase the film-forming effect. At the same time, its outstanding solvent effect and strong agglomeration ability, and lithium titanate have strong fluxing properties, can simultaneously possess both adhesion and easy high-temperature peeling properties. By spraying glass lubricant separately for multiple forging processes, differentiated processing can be achieved using modified glass lubricant and regular glass lubricant, taking into account differences in material structure and heating temperature. This prevents chemical reactions such as oxidation from occurring on the alloy surface during processing, reduces material loss, provides better lubrication performance during forging, and ensures product precision and surface quality. Attached Figure Description

[0054] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0055] The present invention will now be described in more detail with reference to specific embodiments, so as to better demonstrate the advantages of the present invention.

[0056] Three TC4 titanium alloy samples were taken from different furnaces. Due to the differences between the different furnaces, the phase transformation points of the TC4 titanium alloys obtained also differed. The phase transformation points were determined by metallographic method. The T values ​​were obtained for each sample. β TC4 titanium alloy billet with three transformation points: 975℃, 985℃, and 995℃.

[0057] Example 1:

[0058] A method for die forging aircraft blades includes the following steps:

[0059] S1. Blank cutting:

[0060] Take T β The TC4 titanium alloy billet, heated to 985℃, has its two ends beveled and then placed in an electric furnace at 165℃ for 45 minutes.

[0061] S2, One-time spraying:

[0062] After heat preservation, the material is removed and a glass lubricant is evenly sprayed onto the surface of the blank. The thickness of the glass lubricant coating is 0.04 mm. After spraying, the glass lubricant is allowed to dry and cure naturally to obtain the treated material. The glass lubricant used is commercially available.

[0063] S3, upsetting;

[0064] The charging furnace is preheated to 945°C, then the processed material is placed into the charging furnace and held at that temperature for 30 minutes. It is then placed into a preheated mold for upsetting to obtain the upset part; wherein, the T... β The phase transformation point temperature of the billet was determined using a flat forging machine with a striking energy of 630T.

[0065] S4, Second coat:

[0066] The upsetting part is subjected to secondary spraying. The upsetting part is placed in an electric furnace at a temperature of 165℃ and held for 40 minutes. After being removed, glass lubricant is sprayed on the surface of the upsetting part. The coating thickness of the glass lubricant is 0.04mm. After the spraying is completed, the glass lubricant is allowed to dry and cure naturally to obtain the upsetting material.

[0067] S5. Heating of the forging material:

[0068] The charging furnace is preheated to 945℃, and then the forging material is placed in and held for 38 minutes. The forging material is then placed in a preheated mold for pre-forging to obtain a pre-forged part. The operation time from the forging material leaving the furnace to the completion of forging is 15 seconds. The pre-forging is performed using a screw press with an impact energy of 625T.

[0069] S6. Pre-forging treatment:

[0070] The pre-forged parts were polished and ground, and dimensional etching was performed, with a single-sided etching amount of 0.09 mm. Then, the pre-forged parts were sprayed three times. The pre-forged parts were placed in an electric furnace at a furnace temperature of 165℃ and kept at that temperature for 45 minutes. After being removed, glass lubricant was sprayed on the surface of the pre-forged parts. The coating thickness of the glass lubricant was 0.04 mm. After the spraying was completed, the glass lubricant was allowed to dry and cure naturally.

[0071] S7. Heating and final forging of pre-forged parts:

[0072] Because of T β The temperature is 985℃, based on the phase transition temperature T of the raw material. β The heating temperature of the pre-forged part after step S6 is determined to be 980℃. <T β ≤990℃, that is, the heating temperature of the pre-forging is determined to be 940℃; constant temperature heating for 20 minutes, then put into the preheated mold for final forging to obtain the final forging. The operation time from the final forging to the completion of forging is 9 seconds.

[0073] The final forging impact energy was determined as follows: using the Deform software for simulation, the impact energy F1 was found to be 1946T; simultaneously, the impact energy F2 was calculated to be 1583T according to the following formula.

[0074] F2=KS / Q

[0075] In the formula, F is the nominal tonnage of the screw press, in tons; K is the forging coefficient, with a value of 5 tons / cm². 2 S represents the horizontal projected area of ​​the forging, in cm². 2 Q is the deformation coefficient, with a value of 1.1.

[0076] Then, the sum of 0.2*F1 and 0.8*F2 is calculated to obtain the impact energy budget value F as 1655T. Through on-site forming experiments, the value of k*F is obtained as 1000T, and the value of k is taken as 0.604. Therefore, the impact energy of the screw press used in the final forging process is 1000T.

[0077] S8. Perform post-processing on the final forging:

[0078] S8-1. Trim the final forging in the mold using residual heat, completing the trimming 12 seconds after forging. Then, shot blast the trimmed final forging, grind, and shot blast again until the surface is free of defects and dirt to obtain the trimmed part.

[0079] S8-2. Place the cut-edge part into a preheating furnace for heating. The temperature inside the preheating furnace is 850℃ and the temperature is held for 12 minutes.

[0080] S8-3. Remove the cut edge part and use a mold for correction. The operation time from the forging exits the furnace to the completion of forging is 9 seconds. Then, after surface treatment by shot blasting, the aircraft blade is obtained. The shot blasting process conditions are: shot blasting amount 200 kg / min, shot blasting time 15 min.

[0081] Example 2

[0082] The difference between this embodiment and Embodiment 1 is that the temperature parameters are different. In step S1, the billet is placed in an electric furnace with a furnace temperature of 150°C during blanking. In step S4, the forging is placed in an electric furnace with a furnace temperature of 180°C during secondary spraying. In step S6, the pre-forging is placed in an electric furnace with a furnace temperature of 150°C for heat preservation. In step S8-2, the temperature of the charging furnace is 870°C.

[0083] Example 3

[0084] The difference between this embodiment and Embodiment 1 is that the temperature parameters are different. In step S1, the billet is placed in an electric furnace with a furnace temperature of 180°C during blanking. In step S4, the forging is placed in an electric furnace with a furnace temperature of 150°C during secondary spraying. In step S6, the pre-forging is placed in an electric furnace with a furnace temperature of 180°C for heat preservation. In step S8-2, the temperature of the charging furnace is 830°C.

[0085] Example 4

[0086] The difference between this embodiment and Embodiment 1 is that the time parameters are different: Step S1 is kept warm for 60 minutes; Step S3 is kept warm for 28 minutes; Step S4 is kept warm for 60 minutes; Step S5 is kept warm for 35 minutes; Step S6 is kept warm for 60 minutes; Step S7 is kept warm at a constant temperature for 22 minutes; Step S8-2 is kept warm for 15 minutes.

[0087] Example 5

[0088] The difference between this embodiment and Embodiment 1 is that the time parameters are different: Step S1 is kept warm for 30 minutes; Step S3 is kept warm for 2 minutes; Step S4 is kept warm for 30 minutes; Step S5 is kept warm for 40 minutes; Step S6 is kept warm for 30 minutes; Step S7 is kept warm at a constant temperature for 16 minutes; Step S8-2 is kept warm for 10 minutes.

[0089] Example 6

[0090] The difference between this embodiment and Embodiment 1 is that the raw materials of the glass lubricant, by mass parts, include 22 parts of silicate glass powder, 20 parts of silicon dioxide, 12 parts of molybdenum trioxide, 10 parts of boromagnesia, 8 parts of vinyltrimethoxysilane, and 5 parts of aluminum dihydrogen phosphate.

[0091] The preparation method of glass lubricant includes the following steps:

[0092] S1-1. Silicate glass powder, silicon dioxide, molybdenum trioxide, and boromagnesia are mixed and ground into a mixed powder of 10~80μm. Then, vinyltrimethoxysilane and aluminum dihydrogen phosphate are added to the mixed powder and stirred evenly to obtain a mixture.

[0093] S1-2. The mixture obtained in step S1-1 is put into a high-temperature furnace and melted into molten glass; then cooled to room temperature to obtain a pre-finished product.

[0094] S1-3. Grind the pre-processed material obtained in step S1-2 to 0.5~10μm to obtain glass lubricant.

[0095] Example 7

[0096] The difference between this embodiment and embodiment 6 is that the raw material composition is different: 20 parts silicate glass powder, 25 parts silicon dioxide, 16 parts molybdenum trioxide, 6 parts borosilicate, 7 parts vinyltrimethoxysilane, and 6 parts aluminum dihydrogen phosphate. The coating thickness of the glass lubricant in steps S2, S4 and S6 is 0.03 mm.

[0097] Example 8

[0098] The difference between this embodiment and embodiment 6 is that the raw material composition is different: 25 parts silicate glass powder, 18 parts silicon dioxide, 8 parts molybdenum trioxide, 15 parts boromagnesia, 10 parts vinyltrimethoxysilane, and 4 parts aluminum dihydrogen phosphate. The coating thickness of the glass lubricant in steps S2, S4 and S6 is 0.05 mm.

[0099] Example 9

[0100] The difference between this embodiment and embodiment 6 is that 6% by mass of alcohol ester twelve and 30% by mass of deionized water are added to the glass lubricant obtained in steps S1-3, and the mixture is subjected to water bath sonication for 60 minutes. Then, 5% by mass of lithium titanate is added to the glass lubricant, and the mixture is stirred for 1 hour to form a modified glass lubricant. The modified glass lubricant is used as the glass lubricant in each step.

[0101] Example 10

[0102] The difference between this embodiment and embodiment 9 is that the water bath ultrasonic time is 50 minutes and the single-sided corrosion amount in step S6 is 0.07 mm.

[0103] Example 11

[0104] The difference between this embodiment and embodiment 9 is that the water bath ultrasonic time is 80 minutes and the single-sided corrosion amount in step S6 is 0.1 mm.

[0105] Example 12

[0106] The difference between this embodiment and embodiment 9 is that the spraying in step S2 uses the glass lubricant obtained in steps S1-3; the spraying in step S4 uses a mixed glass lubricant obtained in steps S1-3 and a modified glass lubricant mixed at a mass ratio of 1:3; and the spraying in step S6 uses a modified glass lubricant.

[0107] Example 13

[0108] The difference between this embodiment and embodiment 12 is that the glass lubricant obtained in steps S1-3 is used for spraying in steps S2 and S4; and a modified glass lubricant is used for spraying in step S6.

[0109] Example 14

[0110] The difference between this embodiment and embodiment 12 is that the glass lubricant obtained in steps S1-3 is used in step S2; and the modified glass lubricant is used in steps S6 and S4.

[0111] Example 15

[0112] The difference between this embodiment and Embodiment 1 is that the billet selected is T. β The TC4 titanium alloy material is heated to 975℃, and the heating temperature in steps S3, S5 and S7 is 935℃.

[0113] Example 16

[0114] The difference between this embodiment and Embodiment 1 is that the billet selected is T. β The material is TC4 titanium alloy with a temperature of 995℃. The temperature in step S3 is 955℃, the temperature in step S5 is 955℃, and the heating temperature in step S7 is 950℃.

[0115] Experimental Example

[0116] I. The appearance and mechanical properties of the aircraft blades obtained in Examples 1-16 were tested respectively, and the test results are as follows:

[0117] The blade forgings produced in Examples 1-16 were subjected to 100% visual inspection. The blade forgings in Examples 6-12 all had good surface quality and were free of defects such as cracks and folds. The blade forgings in Examples 1-5 and Examples 15-16 had slight cracks on their surfaces, and their surface quality was not as good as that of Examples 6-12. This indicates that the method used in Examples 6-12 is superior. Metallographic observation of the aerospace blades obtained in Examples 1-16 showed that the grain size was 10 or smaller and the distribution was uniform.

[0118] 1. Investigate the effects of different parameters on the mechanical properties of the blade;

[0119] Comparative Example 1: In step S7, the strike energy is taken as the simulated value F1, and the rest of the processing is the same as in Example 1;

[0120] Comparative Example 2: In the upsetting process of step S3, the pre-forging process of step S5, and the final forging process of step S7, the impact energy used was 25% 2500T screw press.

[0121] Examples 1-5, Examples 15-16, and Comparative Example 1 were compared, as shown in Table 1.

[0122]

[0123] As can be seen from Table 1, all embodiments have excellent mechanical properties, and the strength and elongation after fracture of the obtained aircraft blades meet the relevant standard requirements. Among them, Embodiment 1 has better strength performance. Comparing Embodiment 1, Embodiment 2 and Embodiment 3, it can be found that the temperature parameter in Embodiment 1 is better. Comparing Embodiment 1, Embodiment 4 and Embodiment 5, it can be found that the time parameter in Embodiment 1 is better.

[0124] Comparing Example 1 and Comparative Example 1, it can be found that the strength of the aircraft blade obtained in Comparative Example 1 is not much different from that in Example 1, and the method of Example 1 can save energy; at the same time, when using the impact energy parameters of Comparative Example 2, the aircraft blade is not formed, and its strength and other parameters do not meet the requirements.

[0125] Comparing Examples 1, 15, and 16, it can be found that the heating temperature of multiple billets at different phase transformation points is determined by corresponding methods, and the resulting products all have good properties and meet the usage standards. Among them, the high-temperature performance of Example 16 is more preferred.

[0126] 2. Investigate the effects of different glass lubricants on the mechanical properties of aircraft blades;

[0127] Examples 1 and 6-12 were compared, as shown in Table 2;

[0128]

[0129] As can be seen from Table 2, comparing Example 1 and Example 6, the glass lubricant of Example 6 is more preferred than that of Example 1. Comparing Example 6 and Example 9, the modified glass lubricant of Example 9 is more preferred. Comparing Example 9 and Example 12, the spraying method of the glass lubricant in Example 12 is more preferred. Comparing Examples 6-8, the raw material composition of the glass lubricant in Example 6 is more preferred. Comparing Examples 9-11, the water bath ultrasonic time of Example 9 is more preferred. Comparing Examples 12-14, the spraying method of Example 12 is more preferred.

Claims

1. A method for die forging aircraft blades, characterized in that, Includes the following steps: S1. Blank cutting: Chamfer both ends of the billet and then place it in an electric furnace at a temperature of 150~180℃ and hold for 30~60 minutes. S2, One-time spraying: After heat preservation, the material is removed and a glass lubricant is evenly sprayed onto the surface of the blank. The thickness of the glass lubricant coating is 0.03~0.05mm. After spraying, the glass lubricant is allowed to dry and cure naturally to obtain the treated material. S3, upsetting; Preheat the charging furnace to T. β The material is heated to -40℃, then placed in a preheated furnace and held for 28-32 minutes. It is then placed in a preheated mold for upsetting to obtain the upset part; wherein, the T... β The phase transformation point temperature of the billet; S4, Second coat: The upsetting part is then sprayed with a second coating. The upsetting part is placed in an electric furnace at a temperature of 150~180℃ and held for 30~60 minutes. After being removed, a glass lubricant is sprayed onto the surface of the upsetting part. The coating thickness of the glass lubricant is 0.03~0.05mm. After the spraying is completed, the glass lubricant is allowed to dry and cure naturally to obtain the upsetting material. S5. Heating of the forging material: Preheat the charging furnace to T. β -40℃, then put in the forging material and hold for 35~40min; put the forging material into the preheated mold for pre-forging to obtain the pre-forged part. The operation time from the forging material leaving the furnace to the completion of forging is less than or equal to 15s. S6. Pre-forging treatment: Polish and grind the pre-forged parts, then perform dimensional etching with a single-sided etching amount of 0.07~0.1mm; then spray the pre-forged parts three times, place them in an electric furnace at a temperature of 150~180℃ and hold for 30~60 minutes, remove them and spray glass lubricant on the surface of the pre-forged parts, with a coating thickness of 0.03~0.05mm, and allow the glass lubricant to dry and cure naturally after spraying. S7. Heating and final forging of pre-forged parts: Based on the phase change temperature T of the raw material β Determine the heating temperature of the pre-forged part after step S6, and heat it at a constant temperature for 16~22 minutes. Then place it in the preheated mold for final forging to obtain the final forging part. The operation time from the final forging part being taken out of the furnace to the completion of forging should not exceed 10 seconds. The method for determining the heating temperature of the pre-forging after step S6 is as follows: when T β When the temperature is ≤980℃, the heating temperature of the pre-forged part is T. β -40℃; when 980℃ <T β When the temperature is ≤990℃, the heating temperature of the pre-forged part is 940℃; when T β When the temperature is >990℃, the heating temperature of the pre-forging is 950℃; The raw materials of the glass lubricant, by weight, include 20-25 parts silicate glass powder, 18-25 parts silicon dioxide, 8-16 parts molybdenum trioxide, 6-15 parts boromagnesium stone, 7-10 parts vinyltrimethoxysilane, and 4-6 parts aluminum dihydrogen phosphate. The preparation method of the glass lubricant includes the following steps: S1-1. Silicate glass powder, silicon dioxide, molybdenum trioxide, and boromagnesia are mixed and ground into a mixed powder of 10~80μm. Then, vinyltrimethoxysilane and aluminum dihydrogen phosphate are added to the mixed powder and stirred evenly to obtain a mixture. S1-2. The mixture obtained in step S1-1 is put into a high-temperature furnace and melted into molten glass; then cooled to room temperature to obtain a pre-finished product. S1-3. Grind the pre-processed material obtained in step S1-2 to 0.5~10μm to obtain glass lubricant; Add 6% by mass of alcohol ester dodecyl and 30% by mass of deionized water to the glass lubricant obtained in steps S1-3, and perform ultrasonication in a water bath for 50-80 minutes. Then add 5% by mass of lithium titanate to the glass lubricant and stir for 1 hour to form a modified glass lubricant. The spraying in step S2 uses the glass lubricant obtained in steps S1-3; the spraying in step S4 uses a mixed glass lubricant obtained in steps S1-3 and a modified glass lubricant mixed at a mass ratio of 1:3; the spraying in step S6 uses a modified glass lubricant, and the blank is TC4 alloy.

2. The method for die forging aircraft blades as described in claim 1, characterized in that, It also includes: Step S8, post-processing of the final forging: S8-1. Trim the final forging in the mold using residual heat, and complete the trimming within 15 seconds after forging. Then, shot blast, grind, and shot blast again on the trimmed final forging until there are no defects or dirt on the surface to obtain the trimmed part. S8-2. Place the cut-edge part into a warm-loading furnace for heating. The temperature inside the warm-loading furnace is 830~870℃, and the temperature is maintained for 10~15 minutes. S8-3. Remove the cut edge part, use a mold for correction, and the operation time from the forging to the completion of forging is less than or equal to 10 seconds; then use shot blasting for surface treatment to obtain the aircraft blade.

3. The method for die forging aircraft blades as described in claim 2, characterized in that, The shot blasting process conditions in step S8-1 are: shot blasting rate 200 kg / min, shot blasting time 15 min.

4. The method for die forging aircraft blades as described in claim 1, characterized in that, In the upsetting process of step S3, a flat forging machine is used with an impact energy of 630T; in the pre-forging process of step S5, a screw press is used with an impact energy of 625T; in the final forging process of step S7, a screw press is used with an impact energy of 1000T.

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