A preparation process of a high-uniformity TC25G high-temperature titanium alloy large-size fine-grain blisk

Abstract

The application discloses a preparation process of a high-uniformity TC25G high-temperature titanium alloy large-size fine-grain integral blade disc, which comprises the following steps: performing open forging of an alloy ingot at 1100 DEG C to 1200 DEG C, then performing 1-time upsetting and drawing deformation of the obtained blank at 10 DEG C to 30 DEG C above a beta phase transformation point, water cooling after forging, heating the blank to 800 DEG C to 840 DEG C, keeping for 6 h to 10 h, then heating to 920 DEG C to 960 DEG C with a furnace, and then performing forging, then performing 6 to 8-time upsetting and drawing deformation of the blank at 80 DEG C to 20 DEG C below the beta phase transformation point, then performing forming of the blank at 60 DEG C to 40 DEG C below the beta phase transformation point, and obtaining a forged blank; finally, performing solid solution and aging heat treatment on the obtained forged blank, and finally obtaining an integral blade disc forging blank. The process is suitable for preparing integral blade disc forgings with a size of 600 mm to 1300 mm and a height of 60 mm to 120 mm, and the structure uniformity and performance of the forgings are superior to those of traditional processes.

Description

Technical Field

[0001] This invention belongs to the field of new material processing, specifically involving a preparation process for a large-size fine-grained integral bladed disk of high-uniformity TC25G high-temperature titanium alloy. Background Technology

[0002] TC25G titanium alloy is an α+β two-phase titanium alloy possessing the "three highs" characteristics of high temperature resistance, high strength, and high toughness, with a long-term operating temperature reaching 550℃. Compared with traditional two-phase titanium alloys (such as TA15, TC4, TC11, and TA12A), TC25G alloy forgings, rings, and castings exhibit significant advantages in overall performance; and these performance advantages become increasingly pronounced with rising temperatures. TC25G alloy has been successfully applied in Russian engines, with well-established technical standards and process specifications. Its service life can exceed 6000 hours below 500℃ and over 3000 hours at 550℃. It is primarily used in the rotor discs (disc-drum electron beam welded structure) and blades of the PД33 compressor, and is also widely used in other Russian engines, in addition to rotating parts, for mounting edges and stator components such as casings. TC25G is an essential material for the 450–550℃ high-pressure compressors of advanced Russian aero engines.

[0003] Improving the dimensions of titanium alloy bars and forgings through optimized hot working processes while ensuring stability and performance consistency is a goal that materials researchers are constantly pursuing, and it is also one of the technical challenges that the forging field has been eager to solve. Summary of the Invention

[0004] The purpose of this invention is to provide a manufacturing process for large-size, fine-grained integral bladed disks made of highly uniform TC25G high-temperature titanium alloy. Compared to traditional processes, this process is suitable for manufacturing large-size integral bladed disk forgings, and the microstructure uniformity and metallurgical quality stability of the forgings are significantly improved. This invention is simple to operate, has a short process, and high stability, making it suitable for industrial production.

[0005] This invention provides a process for manufacturing a large-size, fine-grained integral bladed disk of high-uniformity TC25G high-temperature titanium alloy, the specific steps of which are as follows:

[0006] Step 1) First, heat the alloy ingot to 1100℃~1200℃, hold it at that temperature for 15h~35h, then remove it from the furnace for forging, completing one upsetting and drawing deformation; then return it to the furnace for holding for 1h~2h, and complete another upsetting and drawing deformation, with each upsetting deformation rate being 0.2s. -1 ~0.08s -1 The deformation amount in a single upsetting process shall not be less than 50%, and the billet shall be air-cooled after forging to obtain the billet.

[0007] Step 2) The billet obtained in Step 1) is subjected to a single upsetting and drawing deformation at a temperature 10°C to 30°C above the β phase transformation point, with the upsetting compression deformation rate at 0.2 s. -1 ~0.08s -1 Between these conditions, the upsetting deformation is ≥50%, and the material is water-cooled after forging;

[0008] Step 3) Heat the billet to 800℃~840℃ and hold for 6h~10h. Then, raise the furnace temperature to 920℃~960℃ to complete one round of upsetting and drawing deformation. Then, return the billet to the furnace and hold for 1h~2h before completing another round of upsetting and drawing deformation. The upsetting pressing rate is 0.05s. -1 ~0.04s -1 Between these values, the upsetting deformation is between 35% and 45%.

[0009] Step 4) Heat the billet to 80℃~20℃ below the phase transformation point and perform upsetting and drawing deformation 6~8 times, requiring an upsetting rate of 0.05s per heat. -1 ~0.04s -1 The deformation is between 30% and 50%, and the cumulative forging ratio is ≥3.3. The final forging temperature is ≥910℃.

[0010] Step 5) Heat the billet to 40-60°C below the β phase transformation point for forming, requiring a deformation rate of 0.005°C per heat cycle. -1 ~0.05 -1 Between 30% and 40%, a forging blank is obtained;

[0011] Step 6) Perform solution treatment and aging heat treatment on the forged billet obtained in Step 5), wherein the solution heat treatment regime is: T β The temperature is between 50℃ and 20℃, held for 1 to 3 hours, and then air-cooled or air-cooled after being taken out of the furnace; the aging heat treatment is: held at 530℃ to 560℃ for 2 to 8 hours and then air-cooled.

[0012] The preferred embodiment of the preparation process of a large-size fine-grained integral bladed disk of high-uniformity TC25G high-temperature titanium alloy is as follows: in step 3), after the billet is upset, it is returned to the furnace for reheating for 1 to 3 hours, and then the drawing process is continued.

[0013] The preferred embodiment of the manufacturing process for a large-size fine-grained integral bladed disk of high-uniformity TC25G high-temperature titanium alloy is as follows: the forming method used in step 4) is an isothermal or near-isothermal forming process; when using an isothermal or near-isothermal die forging process, the die is heated to 0℃~60℃ below the billet heating temperature, and the deformation rate is 0.005s. -1 ~0.05s -1 .

[0014] The beneficial effects of this invention are:

[0015] 1) The integral bladed disk forging prepared by this invention has a diameter between 600mm and 1300mm and a height between 60mm and 120mm. The microstructure of each part of the forging is uniform and the performance is stable.

[0016] 2) The room temperature tensile strength of any part of the forging described in this invention is not less than 1100 MPa, yield strength is not less than 950 MPa, elongation is not less than 15%, and shrinkage is not less than 25%; after the sample is exposed to heat at 550℃ for 100 hours, the elongation is not less than 10% and the shrinkage is not less than 20%; the tensile strength at 500℃ is not less than 850 MPa; the yield strength is not less than 650 MPa; the elongation is not less than 20% and the shrinkage is not less than 40%; the tensile strength at 550℃ is not less than 750 MPa, yield strength is not less than 600 MPa, elongation is not less than 25.0%, and shrinkage is not less than 50%.

[0017] The forging process of this invention can increase the size of the forging without increasing the process flow, while improving the uniformity of the forging structure and its properties. Attached Figure Description

[0018] Figure 1 Here is a high-magnification image of the microstructure near the surface of the forging blank prepared in Example 1;

[0019] Figure 2 A high-magnification microstructure photograph of the center of the forging billet prepared in Example 1;

[0020] Figure 3 A high-magnification microstructure near the surface of the forged billet prepared in Example 2;

[0021] Figure 4 A high-magnification micrograph of the center of the forging billet prepared in Example 2;

[0022] Figure 5 Schematic diagrams of the forgings prepared in Examples 3 and 4;

[0023] Figure 6 Here is a high-magnification image of the microstructure of the forged wheel rim prepared in Example 3;

[0024] Figure 7 Here is a high-magnification microstructure image of the forged spokes prepared in Example 3;

[0025] Figure 8 Here is a high-magnification microstructure image of the forged wheel hub prepared in Example 3;

[0026] Figure 9 Here is a high-magnification image of the microstructure of the forged wheel rim prepared in Example 3;

[0027] Figure 10 Here is a high-magnification microstructure image of the forged spokes prepared in Example 3;

[0028] Figure 11 This is a high-magnification microstructure image of the forged wheel hub prepared in Example 3. Detailed Implementation

[0029] Example 1:

[0030] The TC25G ingot used in the example has a diameter of 600 mm and a length of 1300 mm. Its chemical composition is: Al: 6.51%, Sn: 1.93%, Zr: 3.58%, Mo: 3.91%, Si: 0.21%, W: 0.96%, and its β transformation temperature is 985℃.

[0031] Step 1) Heat the alloy ingot to 1150℃, hold for 20 hours, then remove from the furnace and forge, completing one upsetting and drawing deformation; then return to the furnace and hold for 2 hours to complete another upsetting and drawing deformation, obtaining the billet; the deformation rate of each upsetting is 0.1s. -1 The deformation amount in a single upsetting process shall not be less than 50%, and the billet shall be air-cooled after forging to obtain the billet.

[0032] Step 2) Heat the billet obtained in Step 1) to 1005℃ and perform one upsetting and drawing deformation. The upsetting deformation is 52% and the deformation rate is 0.1s. -1 The forging ratio is 3.6, and the material is water-cooled after forging.

[0033] Step 3) Heat the billet to 840℃ and hold for 10 hours, then raise the furnace temperature to 960℃ for one upsetting and drawing deformation. Then return it to the furnace and hold for 2 hours before performing another upsetting and drawing deformation. The upsetting pressure is 40% and the deformation rate is 0.04s. -1 After forging, air cool;

[0034] Step 4) Heat the billet to 955℃ and perform upsetting and drawing deformation forging 8 times. The upsetting deformation amount in each time is between 37% and 40%, and the cumulative forging ratio is between 3.3 and 3.5. After forging, air cool.

[0035] Step 5) According to the design dimensions of the final forging, the billet is cut using a saw and formed at 950℃ with a forming deformation of 40% and a deformation rate of 0.01s. -1 A forged billet is obtained;

[0036] Step 6) Perform solution treatment and aging heat treatment on the forging billet. The solution treatment process is as follows: 950 ℃, hold for 3 hours, and air cool after removal from the furnace. The aging heat treatment process is as follows: 540 ℃, hold for 6 hours, and then air cool. Finally, the surface is machined to obtain a forging with a diameter of 1000 mm and a height of 120 mm.

[0037] Example 2:

[0038] This embodiment is a comparative example of Example 1, and the selected ingot size, chemical composition, and β transformation temperature are exactly the same as those in Example 1.

[0039] In this embodiment, the forging billet is directly heated to 960°C in step 3 for upsetting and drawing deformation. The other steps are exactly the same as in embodiment 1, and finally a forging with a diameter of 1000mm and a height of 120mm is obtained.

[0040] The microstructure and mechanical properties of the forgings from Examples 1 and 2 were compared and analyzed. The high-magnification microstructure of the forging from Example 1 was a bimodal microstructure, with a primary α content of approximately 20%. The original β grains were fine and uniform in size, and the primary α was evenly distributed without obvious aggregation. There were no significant differences in the microstructure at different locations. Figure 1 , Figure 2 The forgings exhibit room temperature tensile strength exceeding 1100 MPa, 500℃ tensile strength exceeding 850 MPa, and 550℃ tensile strength exceeding 780 MPa. The forgings demonstrate good plasticity; after 550℃ / 100h heat exposure, the room temperature tensile properties of the forgings do not significantly decrease, indicating good thermal stability. Example 2 shows a bimodal microstructure in the forging, with a primary α content of approximately 21% and uneven distribution. The initial β grains are relatively coarse and of uneven size. Figure 3 , Figure 4 The tensile test results showed that the tensile strength varied greatly at different locations of the forging, and the overall strength was relatively low.

[0041] Table 1 Tensile properties of forgings in Example 1

[0042]

[0043]

[0044] Table 2 Thermal stability in Example 1

[0045]

[0046] Table 3 Tensile properties of forgings in Example 2

[0047]

[0048] Table 4 Thermal stability in Example 2

[0049]

[0050] Example 3:

[0051] The TC25G ingot used in the example has a diameter of 600 mm and a length of 1300 mm. Its chemical composition is: Al: 6.55%, Sn: 2.01%, Zr: 3.51%, Mo: 3.89%, Si: 0.19%, W: 0.96%, and its β transformation temperature is 987℃.

[0052] Step 1) Heat the alloy ingot to 1150℃, hold for 20 hours, then remove from the furnace and forge, completing one upsetting and drawing deformation; then return to the furnace and hold for 2 hours to complete another upsetting and drawing deformation, obtaining the billet. The deformation rate of each upsetting is 0.1s. -1 The deformation amount in a single upsetting process shall not be less than 50%, and the billet shall be air-cooled after forging to obtain the billet.

[0053] Step 2) The billet obtained in Step 1) is subjected to upsetting and drawing deformation once at 1010℃. The upsetting deformation is 52% and the deformation rate is 0.1s. -1 The forging ratio is 3.5, and the material is water-cooled after forging.

[0054] Step 3) Heat the billet to 840℃ and hold for 8 hours. Then, raise the temperature to 950℃ in the furnace and perform upsetting and drawing deformation in one pass. Then, return the billet to the furnace and hold for 2 hours. After that, perform upsetting and drawing deformation again. The upsetting deformation amount is 40% and the deformation rate is 0.05s-1. After forging, air cool.

[0055] Step 4) Heat the billet to 947℃ and perform upsetting and drawing deformation forging 7 times. The roughing deformation amount in each heat is 40%, the deformation rate is 0.05s-1, and the cumulative forging ratio is between 3.5 and 3.8. After forging, air cool.

[0056] Step 5) According to the forging design, the blank is cut using a saw, and a near-isothermal die forging process is adopted. The die is heated to 900°C, the forging blank is heated to 950°C, and the deformation rate is 0.01s. -1 The deformation amount is 40%, and after forging, it is air-cooled to obtain a die forging blank;

[0057] Step 6) Finally, the forging billet undergoes solution treatment and aging heat treatment. The solution heat treatment regime is: 955 ℃, held for 2 hours, and then air-cooled after removal from the furnace; the aging heat treatment regime is: 540 ℃, held for 6 hours, and then air-cooled. Finally, the surface is machined to obtain a forging billet with a diameter of 1300 mm and a height of 100 mm.

[0058] Example 4:

[0059] This embodiment is a comparative example of Example 3, and the selected ingot size, chemical composition, and β transformation temperature are exactly the same as those in Example 3.

[0060] In this embodiment, the forging billet is directly heated to 960°C in step 3 for upsetting and drawing deformation. The other steps are exactly the same as in embodiment 3, and finally a forging with a diameter of 1300mm and a height of 100mm is obtained.

[0061] Figure 5 Schematic diagrams of the forgings from Examples 3 and 4 are shown. A comparative analysis of the microstructure and mechanical properties of the forgings from Examples 3 and 4 is performed. The high-magnification microstructure of the forging from Example 3 is a typical bimodal microstructure, with a primary α content of approximately 25%. Figures 6-8 The forgings exhibit room temperature tensile strength exceeding 1100 MPa, 500℃ tensile strength exceeding 850 MPa, and 550℃ tensile strength exceeding 770 MPa. The forgings demonstrate good plasticity, with minimal differences in tensile properties across different locations. After 550℃ / 100h heat exposure, the room temperature tensile properties of the forgings did not significantly decrease, indicating good thermal stability. Example 4 shows a high-magnification microstructure of the forging, which is also a bimodal microstructure with approximately 25% primary α content, uneven distribution, coarse primary β grains, and significant differences in microstructure across different locations. Figure 9 (See Figure 10). The differences in microstructure resulted in poor consistency of mechanical properties at different locations of the forging. In addition, compared with Example 3, the overall tensile strength of the forging was lower.

[0062] Table 5 Tensile properties of forgings in Example 3

[0063]

[0064]

[0065] Table 6 Thermal stability in Example 3

[0066]

[0067] Table 7 Tensile properties of forgings in Example 4

[0068]

[0069] Table 8 Thermal stability in Example 3

[0070]

[0071] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A manufacturing process for a large-size, fine-grained integral bladed disk of high-uniformity TC25G high-temperature titanium alloy, characterized in that, The specific steps are as follows: Step 1) First, heat the alloy ingot to 1100℃~1200℃, hold it at that temperature for 15h~35h, then remove it from the furnace for forging, completing one upsetting and drawing deformation; then return it to the furnace for holding for 1h~2h, and complete another upsetting and drawing deformation to obtain the billet. The deformation rate of each upsetting is 0.2s. -1 ~0.08s -1 The deformation amount in a single upsetting process shall not be less than 50%, and the billet shall be air-cooled after forging to obtain the billet. Step 2) The billet obtained in Step 1) is subjected to a single upsetting and drawing deformation at a temperature 10°C to 30°C above the β phase transformation point, with the upsetting compression deformation rate at 0.2 s. -1 ~0.08s -1 Between these conditions, the upsetting deformation is ≥50%, and the material is water-cooled after forging; Step 3) Heat the billet to 800℃~840℃ and hold for 6h~10h. Then, raise the furnace temperature to 920℃~960℃ to complete one round of upsetting and drawing deformation. Then, return the billet to the furnace and hold for 1h~2h before completing another round of upsetting and drawing deformation. The upsetting pressing rate is 0.05s. -1 ~0.04s -1 Between these values, the upsetting deformation is between 35% and 45%. Step 4) Heat the billet to 80℃~20℃ below the phase transformation point and perform upsetting and drawing deformation 6~8 times, requiring an upsetting rate of 0.05s per heat. -1 ~0.04s -1 Between 30% and 50%, the cumulative forging ratio is ≥3.3, and the final forging temperature is ≥910℃; Step 5) Heat the billet to 40°C below the β phase transformation point (60°C to 60°C) for forming, requiring a deformation rate of 0.005 s per heat. -1 ~0.05s -1 Between 30% and 40%, a forging blank is obtained; Step 6) Perform solution treatment and aging heat treatment on the forged billet obtained in Step 5), wherein the solution heat treatment regime is: T β The following conditions apply: heat treatment at 50℃ to 20℃ for 1 to 3 hours, followed by air cooling or air cooling after removal from the furnace; aging heat treatment is: heat treatment at 530℃ to 560℃ for 2 to 8 hours, followed by air cooling. This process can be used to prepare integral bladed disk forgings with diameters ranging from 600 mm to 1300 mm and heights ranging from 60 mm to 120 mm. In step 3), after the billet is upset, it is returned to the furnace for reheating for 1 to 3 hours, and then the drawing process is continued.

2. The manufacturing process of a large-size fine-grained integral bladed disk of high-uniformity TC25G high-temperature titanium alloy according to claim 1, characterized in that: The forming method used in step 4) is an isothermal or near-isothermal forming process; when using an isothermal or near-isothermal die forging process, the die is heated to 0℃~60℃ below the billet heating temperature, and the deformation rate is 0.005s. -1 ~0.05s -1 .

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